Land Resource Regions and

Major Land Resource Areas

of the United States, the

Caribbean, and the Pacific Basin

United States

Department of

Agriculture

Natural Resources

Conservation Service

United States Department of

Agriculture Handbook 296

Land Resource Regions and

Major Land Resource Areas of

the United States, the Caribbean,

and the Pacific Basin

United States Department of Agriculture

Natural Resources Conservation Service

United States Department of Agriculture Handbook 296

Issued 2006
ii

Citation: United States Department of Agriculture, Natural Resources Conservation Service.

2006. Land Resource Regions and Major Land Resource Areas of the United States, the

Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296.

Cover:

Upper left.—An area of Land Resource Region Q (Pacific Basin Region).

Upper right.—Recent volcanic deposits in an area of Land Resource Region W2

(Aleutian Alaska).

Lower left.—Riparian buffer in an area of Land Resource Region M (Central Feed

Grains and Livestock Region).

Lower right.—Rangeland in an area of Land Resource Region B (Northwestern

Wheat and Range Region).

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs

and activities on the basis of race, color, national origin, age, disability, and where applicable,

sex, marital status, familial status, parental status, religion, sexual orientation, genetic

information, political beliefs, reprisal, or because all or a part of an individual’s income is

derived from any public assistance program. (Not all prohibited bases apply to all programs.)

Persons with disabilities who require alternative means for communication of program

information (Braille, large print, audiotape, etc.) should contact USDA’s TARGET Center at

(202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA,

Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-

9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity

provider and employer.
iii

Contents

Preface ...................................................................................vii

Land Resource Regions and Major Land Resource

Areas ................................................................................... 1

Introduction ......................................................................... 1

A—Northwestern Forest, Forage, and Specialty Crop

Region .......................................................................... 9

1—Northern Pacific Coast Range, Foothills, and

Valleys ........................................................................ 11

2—Willamette and Puget Sound Valleys ....................... 12

3—Olympic and Cascade Mountains ........................... 14

4A—Sitka Spruce Belt .................................................. 16

4B—Coastal Redwood Belt .......................................... 19

5—Siskiyou-Trinity Area .............................................. 21

6—Cascade Mountains, Eastern Slope ......................... 23

B—Northwestern Wheat and Range Region .................... 27

7—Columbia Basin ....................................................... 29

8—Columbia Plateau .................................................... 31

9—Palouse and Nez Perce Prairies ................................ 33

10—Central Rocky and Blue Mountain Foothills ....... 35

11—Snake River Plains ................................................. 37

12—Lost River Valleys and Mountains ........................ 38

13—Eastern Idaho Plateaus ........................................... 40

C—California Subtropical Fruit, Truck, and Specialty

Crop Region ............................................................... 43

14—Central California Coastal Valleys ........................ 45

15—Central California Coast Range ............................ 47

16—California Delta ..................................................... 49

17—Sacramento and San Joaquin Valleys .................... 51

18—Sierra Nevada Foothills ......................................... 53

19—Southern California Coastal Plain ......................... 55

20—Southern California Mountains ............................. 57

D—Western Range and Irrigated Region .......................... 61

21—Klamath and Shasta Valleys and Basins ................ 63

22A—Sierra Nevada Mountains ................................... 65

22B—Southern Cascade Mountains ............................. 67

23—Malheur High Plateau ............................................ 69

24—Humboldt Area ....................................................... 71

25—Owyhee High Plateau ............................................ 73

26—Carson Basin and Mountains ................................ 75

27—Fallon-Lovelock Area ............................................ 77

28A—Great Salt Lake Area............................................ 79

28B—Central Nevada Basin and Range ....................... 81

29—Southern Nevada Basin and Range ....................... 83

30—Mojave Desert ........................................................ 85

31—Lower Colorado Desert .......................................... 88

32—Northern Intermountain Desertic Basins ............... 90

34A—Cool Central Desertic Basins and Plateaus ........ 92

34B—Warm Central Desertic Basins and Plateaus ....... 94

35—Colorado Plateau ................................................... 96

36—Southwestern Plateaus, Mesas, and Foothills ........ 99

38—Mogollon Transition ........................................... 101

39—Arizona and New Mexico Mountains ................. 103

40—Sonoran Basin and Range ................................... 105

41—Southeastern Arizona Basin and Range .............. 107

42—Southern Desertic Basins, Plains, and

Mountains ................................................................ 109

E—Rocky Mountain Range and Forest Region ............. 113

43A—Northern Rocky Mountains .............................. 115

43B—Central Rocky Mountains ................................ 116

43C—Blue and Seven Devils Mountains ................... 118

44—Northern Rocky Mountain Valleys ..................... 121

46—Northern Rocky Mountain Foothills .................. 123

47—Wasatch and Uinta Mountains ............................ 125

48A—Southern Rocky Mountains .............................. 128

48B—Southern Rocky Mountain Parks ..................... 130

49—Southern Rocky Mountain Foothills .................. 132

51—High Intermountain Valleys ................................. 134

F—Northern Great Plains Spring Wheat Region ............ 137

52—Brown Glaciated Plain ......................................... 139

53A—Northern Dark Brown Glaciated Plains ............ 140

53B—Central Dark Brown Glaciated Plains ............... 142

53C—Southern Dark Brown Glaciated Plains ............ 144

54—Rolling Soft Shale Plain ...................................... 145

55A—Northern Black Glaciated Plains ...................... 147

55B—Central Black Glaciated Plains ......................... 148

55C—Southern Black Glaciated Plains ...................... 150

56—Red River Valley of the North ............................. 152

G—Western Great Plains Range and Irrigated Region ... 155

58A—Northern Rolling High Plains, Northern Part ... 157

58B—Northern Rolling High Plains, Southern Part ... 159

58C—Northern Rolling High Plains, Northeastern

Part ............................................................................ 161

58D—Northern Rolling High Plains, Eastern Part ...... 162

60A—Pierre Shale Plains ............................................. 164

60B—Pierre Shale Plains, Northern Part ..................... 166

61—Black Hills Foot Slopes ....................................... 168

62—Black Hills ........................................................... 170

63A—Northern Rolling Pierre Shale Plains ................ 172
iv

63B—Southern Rolling Pierre Shale Plains ............... 174

64—Mixed Sandy and Silty Tableland and

Badlands................................................................... 176

65—Nebraska Sand Hills ............................................. 178

66—Dakota-Nebraska Eroded Tableland .................... 180

67A—Central High Plains, Northern Part ................... 181

67B—Central High Plains, Southern Part ................... 183

69—Upper Arkansas Valley Rolling Plains ................. 185

70A—Canadian River Plains and Valleys ................... 187

70B—Upper Pecos River Valley ................................. 189

70C—Central New Mexico Highlands ....................... 191

70D—Southern Desert Foothills ................................. 193

H—Central Great Plains Winter Wheat and Range

Region ...................................................................... 195

71—Central Nebraska Loess Hills .............................. 197

72—Central High Tableland ....................................... 198

73—Rolling Plains and Breaks ................................... 200

74—Central Kansas Sandstone Hills ........................... 202

75—Central Loess Plains ............................................ 204

76—Bluestem Hills ..................................................... 206

77A—Southern High Plains, Northern Part ................. 208

77B—Southern High Plains, Northwestern Part ......... 210

77C—Southern High Plains, Southern Part ................ 211

77D—Southern High Plains, Southwestern Part ......... 214

77E—Southern High Plains, Breaks ........................... 215

78A—Rolling Limestone Prairie ................................. 217

78B—Central Rolling Red Plains, Western Part ......... 219

78C—Central Rolling Red Plains, Eastern Part .......... 221

79—Great Bend Sand Plains ....................................... 223

80A—Central Rolling Red Prairies ............................. 225

80B—Texas North-Central Prairies ............................. 227

I—Southwest Plateaus and Plains Range and Cotton

Region ...................................................................... 229

81A—Edwards Plateau, Western Part .......................... 231

81B—Edwards Plateau, Central Part ........................... 232

81C—Edwards Plateau, Eastern Part ........................... 233

81D—Southern Edwards Plateau ................................ 235

82A—Texas Central Basin .......................................... 236

83A—Northern Rio Grande Plain ............................... 238

83B—Western Rio Grande Plain ................................. 240

83C—Central Rio Grande Plain .................................. 242

83D—Lower Rio Grande Plain .................................... 244

83E—Sandsheet Prairie ............................................... 246

J—Southwestern Prairies Cotton and Forage Region ..... 249

82B—Wichita Mountains ........................................... 251

84A—North Cross Timbers ......................................... 252

84B—West Cross Timbers ........................................... 254

84C—East Cross Timbers ............................................ 256

85—Grand Prairie ........................................................ 258

86A—Texas Blackland Prairie, Northern Part ............. 261

86B—Texas Blackland Prairie, Southern Part ............ 262

87A—Texas Claypan Area, Southern Part ................... 265

87B—Texas Claypan Area, Northern Part ................... 267

K—Northern Lake States Forest and Forage Region ...... 269

57—Northern Minnesota Gray Drift ........................... 271

88—Northern Minnesota Glacial Lake Basins ........... 272

89—Wisconsin Central Sands ..................................... 274

90A—Wisconsin and Minnesota Thin Loess and

Till, Northern Part ..................................................... 276

90B—Wisconsin and Minnesota Thin Loess and

Till, Southern Part .................................................... 279

91A—Central Minnesota Sandy Outwash .................. 281

91B—Wisconsin and Minnesota Sandy Outwash ...... 282

92—Superior Lake Plain ............................................. 285

93A—Superior Stony and Rocky Loamy Plains

and Hills, Western Part ............................................. 287

93B—Superior Stony and Rocky Loamy Plains

and Hills, Eastern Part .............................................. 288

94A—Northern Michigan and Wisconsin Sandy

Drift........................................................................... 290

94B—Michigan Eastern Upper Peninsula Sandy

Drift........................................................................... 292

94C—Michigan Northern Lower Peninsula Sandy

Drift........................................................................... 294

94D—Northern Highland Sandy Drift ........................ 296

95A—Northeastern Wisconsin Drift Plain .................. 298

95B—Southern Wisconsin and Northern Illinois

Drift Plain ................................................................. 300

L—Lake States Fruit, Truck Crop, and Dairy Region ..... 303

96—Western Michigan Fruit Belt ............................... 305

97—Southwestern Michigan Fruit and Truck Crop

Belt ........................................................................... 306

98—Southern Michigan and Northern Indiana

Drift Plain ................................................................. 308

99—Erie-Huron Lake Plain ......................................... 310

101—Ontario-Erie Plain and Finger Lakes

Region ...................................................................... 312

M—Central Feed Grains and Livestock Region ............. 315

102A—Rolling Till Prairie .......................................... 317

102B—Till Plains ........................................................ 318

102C—Loess Uplands ................................................. 320

103—Central Iowa and Minnesota Till Prairies ......... 322

104—Eastern Iowa and Minnesota Till Prairies ......... 324

105—Northern Mississippi Valley Loess Hills ........... 326

106—Nebraska and Kansas Loess-Drift Hills ............. 328

107A—Iowa and Minnesota Loess Hills ..................... 330

107B—Iowa and Missouri Deep Loess Hills .............. 332

108A—Illinois and Iowa Deep Loess and Drift,

Eastern Part ............................................................... 334

108B—Illinois and Iowa Deep Loess and Drift,

East-Central Part ....................................................... 336

108C—Illinois and Iowa Deep Loess and Drift,

West-Central Part ...................................................... 338

108D—Illinois and Iowa Deep Loess and Drift,

Western Part .............................................................. 340

109—Iowa and Missouri Heavy Till Plain .................. 342
v

110—Northern Illinois and Indiana Heavy Till

Plain .......................................................................... 344

111A—Indiana and Ohio Till Plain, Central Part ....... 346

111B—Indiana and Ohio Till Plain, Northeastern

Part ............................................................................ 348

111C—Indiana and Ohio Till Plain, Northwestern

Part ............................................................................ 350

111D—Indiana and Ohio Till Plain, Western Part ...... 352

111E—Indiana and Ohio Till Plain, Eastern Part ....... 353

112—Cherokee Prairies ............................................... 355

113—Central Claypan Areas ....................................... 357

114A—Southern Illinois and Indiana Thin Loess

and Till Plain, Eastern Part ....................................... 359

114B—Southern Illinois and Indiana Thin Loess

and Till Plain, Western Part ...................................... 361

115A—Central Mississippi Valley Wooded Slopes,

Eastern Part ............................................................... 363

115B—Central Mississippi Valley Wooded Slopes,

Western Part .............................................................. 365

115C—Central Mississippi Valley Wooded Slopes,

Northern Part ............................................................ 368

N—East and Central Farming and Forest Region ........... 371

116A—Ozark Highland ............................................... 373

116B—Springfield Plain ............................................. 375

116C—St. Francois Knobs and Basins ........................ 377

117—Boston Mountains ............................................. 379

118A—Arkansas Valley and Ridges, Eastern Part ...... 381

118B—Arkansas Valley and Ridges, Western Part ...... 382

119—Ouachita Mountains .......................................... 384

120A—Kentucky and Indiana Sandstone and

Shale Hills and Valleys, Southern Part ..................... 386

120B—Kentucky and Indiana Sandstone and

Shale Hills and Valleys, Northwestern Part .............. 388

120C—Kentucky and Indiana Sandstone and

Shale Hills and Valleys, Northeastern Part ............... 390

121—Kentucky Bluegrass .......................................... 391

122—Highland Rim and Pennyroyal .......................... 393

123—Nashville Basin ................................................. 395

124—Western Allegheny Plateau ................................ 397

125—Cumberland Plateau and Mountains ................. 399

126—Central Allegheny Plateau ................................. 401

127—Eastern Allegheny Plateau and Mountains ....... 403

128—Southern Appalachian Ridges and Valleys ....... 405

129—Sand Mountain .................................................. 407

130A—Northern Blue Ridge ....................................... 409

130B—Southern Blue Ridge ...................................... 411

O—Mississippi Delta Cotton and Feed Grains

Region ...................................................................... 415

131A—Southern Mississippi River Alluvium ............ 417

131B—Arkansas River Alluvium ................................ 419

131C—Red River Alluvium ........................................ 421

131D—Southern Mississippi River Terraces .............. 424

P—South Atlantic and Gulf Slope Cash Crops, Forest,

and Livestock Region .............................................. 427

133A—Southern Coastal Plain ................................... 429

133B—Western Coastal Plain ..................................... 431

134—Southern Mississippi Valley Loess .................... 433

135A—Alabama and Mississippi Blackland

Prairie ........................................................................ 436

135B—Cretaceous Western Coastal Plain .................. 437

136—Southern Piedmont ............................................ 439

137—Carolina and Georgia Sand Hills ....................... 441

138—North-Central Florida Ridge ............................. 443

Q—Pacific Basin Region ................................................ 445

190—Stratovolcanoes of the Mariana Islands ............ 447

191—High Limestone Plateaus of the Mariana

Islands ....................................................................... 448

192—Volcanic Highlands of the Mariana Islands ...... 450

193—Volcanic Islands of Western Micronesia............ 452

194—Low Limestone Islands of Western

Micronesia ................................................................ 454

195—Volcanic Islands of Central and Eastern

Micronesia ................................................................ 455

196—Coral Atolls of Micronesia ................................ 457

197—Volcanic Islands of American Samoa ................. 458

R—Northeastern Forage and Forest Region ................... 461

139—Lake Erie Glaciated Plateau .............................. 463

140—Glaciated Allegheny Plateau and Catskill

Mountains ................................................................ 464

141—Tughill Plateau .................................................. 466

142—St. Lawrence-Champlain Plain .......................... 468

143—Northeastern Mountains .................................... 470

144A—New England and Eastern New York

Upland, Southern Part .............................................. 473

144B—New England and Eastern New York

Upland, Northern Part ............................................... 475

145—Connecticut Valley ............................................ 478

146—Aroostook Area .................................................. 480

S—Northern Atlantic Slope Diversified Farming

Region ...................................................................... 483

147—Northern Appalachian Ridges and Valleys ........ 485

148—Northern Piedmont ............................................ 487

149A—Northern Coastal Plain .................................... 489

149B—Long Island-Cape Cod Coastal Lowland ....... 491

T—Atlantic and Gulf Coast Lowland Forest and

Crop Region ............................................................. 495

150A—Gulf Coast Prairies .......................................... 497

150B—Gulf Coast Saline Prairies ............................... 498

151—Gulf Coast Marsh ............................................... 500

152A—Eastern Gulf Coast Flatwoods ........................ 502

152B—Western Gulf Coast Flatwoods ........................ 504

153A—Atlantic Coast Flatwoods ............................... 506

153B—Tidewater Area ................................................ 508

153C—Mid-Atlantic Coastal Plain ............................. 510
vi

153D—Northern Tidewater Area ................................. 512

U—Florida Subtropical Fruit, Truck Crop, and

Range Region ........................................................... 517

154—South-Central Florida Ridge ............................. 519

155—Southern Florida Flatwoods .............................. 520

156A—Florida Everglades and Associated

Areas ......................................................................... 522

156B—Southern Florida Lowlands ............................ 524

V—Hawaii Region .......................................................... 527

157—Arid and Semiarid Low Mountain Slopes ......... 529

158—Semiarid and Subhumid Low Mountain

Slopes ....................................................................... 530

159A—Humid and Very Humid Volcanic Ash Soils

on Low and Intermediate Rolling Mountain

Slopes ....................................................................... 532

159B—Subhumid and Humid Low and

Intermediate Mountain Slopes ................................. 533

160—Subhumid and Humid Intermediate and

High Mountain Slopes ............................................. 535

161A—Lava Flows and Rock Outcrops ...................... 536

161B—Semiarid and Subhumid Organic Soils on

Lava Flows ............................................................... 537

162—Humid and Very Humid Organic Soils on

Lava Flows ............................................................... 539

163—Alluvial Fans and Coastal Plains ...................... 540

164—Humid and Very Humid Steep and Very

Steep Mountain Slopes ............................................ 542

165—Subhumid Intermediate Mountain Slopes ........ 543

166—Very Stony Land and Rock Land ...................... 544

167—Humid Oxidic Soils on Low and

Intermediate Rolling Mountain Slopes ................... 546

W1—Southern Alaska ..................................................... 549

220—Alexander Archipelago-Gulf of Alaska

Coast ......................................................................... 551

221—Kodiak Archipelago .......................................... 553

222—Southern Alaska Coastal Mountains ................. 555

223—Cook Inlet Mountains ....................................... 556

224—Cook Inlet Lowlands ......................................... 558

225—Southern Alaska Peninsula Mountains ............. 561

W2—Aleutian Alaska ...................................................... 565

226—Aleutian Islands-Western Alaska Peninsula ...... 567

X1—Interior Alaska ......................................................... 569

227—Copper River Basin ........................................... 571

228—Interior Alaska Mountains ................................. 573

229—Interior Alaska Lowlands ................................... 575

230—Yukon-Kuskokwim Highlands .......................... 577

231—Interior Alaska Highlands .................................. 579

232—Yukon Flats Lowlands ....................................... 582

233—Upper Kobuk and Koyukuk Hills and

Valleys ...................................................................... 584

234—Interior Brooks Range Mountains ..................... 586

X2—Western Alaska ........................................................ 589

235—Northern Alaska Peninsula Mountains .............. 591

236—Bristol Bay-Northern Alaska Peninsula

Lowlands .................................................................. 592

237—Ahklun Mountains ............................................ 595

238—Yukon-Kuskokwim Coastal Plain ..................... 597

239—Northern Bering Sea Islands .............................. 599

240—Nulato Hills-Southern Seward Peninsula

Highlands ................................................................. 600

Y—Northern Alaska ......................................................... 603

241—Seward Peninsula Highlands ............................. 605

242—Northern Seward Peninsula-Selawik

Lowlands .................................................................. 607

243—Western Brooks Range Mountains,

Foothills, and Valleys ............................................... 608

244—Northern Brooks Range Mountains .................. 610

245—Arctic Foothills .................................................. 612

246—Arctic Coastal Plain ........................................... 614

Z—Caribbean Region ..................................................... 617

270—Humid Mountains and Valleys .......................... 619

271—Semiarid Mountains and Valleys ....................... 620

272—Humid Coastal Plains ........................................ 623

273—Semiarid Coastal Plains ..................................... 625

References............................................................................ 629

Glossary ............................................................................... 631

Appendices ........................................................................... 639

Appendix I.—MLRAs, EPA Level III Ecoregions, and

Forest Service Ecological Sections .......................... 639

Appendix II.—Area of LRRs and MLRAs ...................... 655

Appendix III.—Water Use................................................ 663

Appendix IV.—Soil Classification .................................. 668
vii

Preface

Natural vegetation is a result of the combination of geography, soils, and climate. People

learned early in human history that soils that produced grass and trees could also produce

grain, fruits, and vegetables. Early soil scientists recognized this relationship. Some of their

earliest publications included a description of the climate and vegetation (or crop types)

typical for particular soils. “Chestnut soils of the temperate to cool semiarid regions of grain

and cattle grazing” is one example. Different social, economic, and political cultures can be

considered outgrowths of the various types of soils, crops, and climate that occur in different

regions. For example, cattle ranchers in western South Dakota are studies in contrast to potato

farmers in northern Maine.

Early farmers and ranchers realized that the different soils and climates they encountered

required them to grow certain types of crops in order to survive economically. Such terms as

“Corn Belt” and “Cotton Belt” were coined because of the crops typically grown by the early

settlers. These were very early versions of land resource areas. As soil mapping progressed

across the country, soil scientists worked with other natural resource managers to subdivide

land into resource units with similar soils, climate, and vegetation or crop types. This work

allowed a few soil scientists and natural resource planners to provide soil interpretations and

soil conservation recommendations that were useful to many landowners in a region instead

of to a few limited individuals.

 Those pioneer efforts resulted in the publication of the first edition of Agricultural

Handbook 296 in 1965. The United States was subdivided into a number of land resource

regions that were made up of many major land resource areas. The similar climate, soils, and

land use activities in each land resource region helped natural resource planners to target

efforts in education and financial and technical assistance.

Agricultural Handbook 296 was used when decisions about regional and national

agricultural issues were made. It helped to identify the need for research and resource

inventories, and it became the vehicle for extrapolating the results of research across political

boundaries. It also became the basis for organizing and operating natural resource

conservation programs. Today, soil survey offices are organized to serve groups of the major

land resource areas defined in this handbook. The handbook was updated in 1978, and the

second edition was printed in 1981. This 2006 version of the handbook is the third edition.

1

Land Resource Regions and Major Land Resource Areas

Introduction

This handbook is an assemblage of currently available

information about land as a resource for farming, ranching,

forestry, engineering, recreation, and other uses. It is a revision

of United States Department of Agriculture (USDA) Handbook

296, Land Resource Regions and Major Land Resource Areas

of the United States, published in 1981 (USDA, 1981).

Revisions consist of:

1) refined delineations of land resource regions

(LRRs) and major land resource areas (MLRAs),

2) addition of 3 new LRRs (including the Pacific

Basin Region) and 70 new MLRAs,

3) a description of the extent of the major

Hydrologic Unit Areas (identified by four-digit

numbers) within each MLRA,

4) updated climate information (1961-1990),

5) descriptions of the sources and quantities of

freshwater used in the year 1990,

6) classification of the identified soils of each region

and area according to the taxonomic system

described in Soil Taxonomy (Soil Survey Staff,

1999), and

7) land use statistics based on the National

Resources Inventory (NRI) of 1997.

Soil scientists in appropriate States wrote the descriptions of

new MLRAs and MLRAs with changed boundaries. The

National Soil Survey Center staff wrote the descriptions of

MLRAs with no boundary changes since 1981. The

information in this handbook is current as of October 2005. The

handbook includes large-scale maps of the LRRs and MLRAs.

Image and geospatial data (digital) file versions of these maps

are available at www.soils.usda.gov.

The information in this handbook provides a basis for

making decisions about national and regional agricultural

concerns, identifies needs for research and resource inventories,

provides a broad base for extrapolating the results of research

within national boundaries, and serves as a framework for

organizing and operating soil surveys and resource

conservation programs.

Land resource categories historically used at State and

national levels are land resource units, land resource areas, and

land resource regions. Land resource units (LRUs) are the basic

units from which major land resource areas (MLRAs) are

determined. They are also the basic units for State land resource

maps. LRUs are typically coextensive with State general soil

map units, but some general soil map units are subdivided into

LRUs because of significant geographic differences in soils,

climate, water resources, or land use. LRUs generally are several

thousand acres in size. A unit can be one continuous area or

several separate areas that are near each other. In 2005, these

areas were designated as common resource areas (CRAs) within

the Natural Resources Conservation Service (NRCS).

CRAs are created by subdividing MLRAs by topography,

other landscape features, hydrologic units, resource concerns,

resource uses, and human considerations affecting use and soil

and water conservation treatment needs. Common resource

areas, or land resource units, are not described in this handbook

and are not shown on the national map.

Major land resource areas are geographically associated land

resource units. Land resource regions are a group of

geographically associated major land resource areas.

Identification of these large areas is important in statewide

agricultural planning and has value in interstate, regional, and

national planning. In order to make this handbook more useful

to other Federal agencies and private parties using ecological

regions for planning or evaluation of natural resources

programs and policies, Appendix I cross-references MLRAs

with Environmental Protection Agency Level III Ecoregions

(USEPA, 2003; Omernik, 1987) and U.S. Forest Service

ecological sections (Cleland and others, 2005; McNab and

others, 2005).

In this handbook, major land resource areas are generally

designated by Arabic numbers and identified by a descriptive

geographic name. Examples are MLRA 1 (Northern Pacific

Coast Range, Foothills, and Valleys); MLRA 154 (SouthCentral Florida Ridge); and MLRA 230 (Yukon-Kuskokwim

Highlands).

Some MLRAs are designated by an Arabic number and a

letter because previously established MLRAs have been

divided into smaller, more homogeneous areas, for example,

MLRAs 102A, 102B, and 102C. The use of numbers and letters

to identify the newly created MLRAs requires fewer changes in

existing information in records and in databases. A few MLRAs

consist of two or more parts separated for short distances by

other land resource areas. In places one of these parts is widely

separated from the main body of the MLRA and is in an

adjoining LRR. The description of the respective MLRA also

applies to these outlying parts.
2 Major Land Resource Areas

Almost every MLRA has small areas, typically tens of square

miles or less, that may not fit the overall description of that

particular MLRA. Such areas may fit the description of an

adjacent or nearby MLRA. These small areas are not described

or shown on maps in this handbook.

Land resource regions generally are designated by capital

letters and identified by descriptive names. An example is

“A—Northwestern Forest, Forage, and Specialty Crop Region.”

Arabic numbers were added to the LRRs identified by the

letters W and X after all of the letters in the alphabet were used.

The dominant physical characteristics of the 28 land

resource regions are briefly described in separate sections. A

location map for each LRR is provided with each LRR

description. More detailed descriptions of the 278 major land

resource areas follow the LRR descriptions.

A location map for each MLRA within its LRR is provided

with each MLRA description. The introductory paragraph in

this description lists the State or States in which an MLRA

occurs and the areal extent of each MLRA. Appendix II shows

the area and proportionate extent of all LRRs and MLRAs. The

major cities or towns, highways, and Federal or State

installations of significant national interest are indentified in

each introductory paragraph. This paragraph is followed by

headings for physiography, geology, climate, water, soils,

biological resources, and land use for each MLRA.

Physiography.—The physiographic section, province, and

division are listed for each MLRA. This information is based

mainly on a classification system for the original 48 States

within the United States (Fenneman and Johnson, 1946).

Wahrhaftig’s (1965) system was used to describe MLRAs in

Alaska. There is no formal system of physical land divisions for

Hawaii, the Pacific Basin, or Puerto Rico and the Virgin Islands.

The topography and natural features of each area are described.

The height above sea level and the relief, including significant

exceptions, if applicable, are provided for the area as a whole.

Units of elevation and relief are feet and meters. The units are

typically rounded to the nearest 5 or 10 feet or meters. If the

elevation is less than 50 feet or 15 meters, it generally is

expressed in the nearest whole number. The conversion factor is

3.28 feet per meter.

The extent of the major Hydrologic Unit Areas (Seaber and

others, 1984) within each MLRA is given in percent. These

areas are identified by four-digit numbers. Digital coverage of

eight-digit Hydrologic Unit Area boundaries was intersected

with the digital MLRA map, and the eight-digit areas were

aggregated to the four-digit level when these statistics were

generated. The major rivers or streams draining each MLRA

and any National Scenic or National Wild and Scenic River

reaches within an MLRA are identified.

Geology.—The bedrock and surficial geology of each

MLRA is described. This information was derived from a wide

variety of State and Federal maps and reports that are not

included in the list of references. The geologic time scale is

shown in the Glossary.

Climate.— Spatial climate products (digital maps) were

obtained from the NRCS National Water and Climate Center

(NWCC). Parameter-elevation Regressions on Independent

Slopes Model (PRISM) data developed by the Spatial Climate

Analysis Service at Oregon State University, in cooperation

with NWCC, were used to generate mean annual precipitation

(MAP) and mean annual air temperature (MAAT) maps for the

lower 48 States (figs. 1 and 2). PRISM data are based on

National Weather Service climate records accumulated for the

period 1961 through 1990. Only MAP data were available in

digital form for Alaska, Hawaii, and Puerto Rico and the Virgin

Islands (fig. 3) and for the Pacific Basin (fig. 4). Local NRCS

staff provided the MAAT data for the climate narrative

describing these areas. The data were primarily extrapolated

from local weather station statistics within historic or ongoing

soil survey areas.

The digital PRISM maps were intersected with the

appropriate digital MLRA maps to determine the climate

statistics for each MLRA. The climatic data include (1) a range

of the average annual precipitation for the driest to wettest parts

of the MLRA, (2) the seasonal distribution of precipitation, (3)

a range of the average annual temperature, and (4) the shortest,

longest, and average length of the freeze-free period.

The lowest and highest average annual rainfall and

temperature values are reported as calculated from the PRISMMLRA map intersection. Units of rainfall are inches and

millimeters. The inches are not rounded, and the millimeters are

rounded to the nearest 5 or 10 millimeters. The conversion

factor is 25.4001 millimeters per inch. Units of temperature are

in degrees Fahrenheit and centigrade. The degrees in

Fahrenheit are not rounded, and the degrees in centigrade are

rounded to the nearest whole number. Centigrade degrees are

calculated by subtracting 32 degrees from the Fahrenheit

degrees and multiplying by 5

/9 (0.5556).

If any inches of snow are listed, the centimeters also are

provided. Snow amounts are not calculated values and are

derived from a number of references and historical records that

may be outside the period of record for the PRISM data (1961-

1990). The inches of snow are listed as whole numbers and may

or may not be rounded. The centimeters are rounded to the

nearest 5 or 10 centimeters. The conversion factor is 2.54

centimeters per inch.

The average length and the actual length of the shortest and

longest freeze-free periods within each MLRA are calculated by

intersecting the digital PRISM and MLRA maps. The days

listed in the narrative are rounded to the nearest 5 or 10 days.

Water.—The United States Geological Survey (USGS)

publishes reports at approximately 5-year intervals on the

estimated use of fresh and saline, surface and ground water in

each State within the United States and in Puerto Rico and the

Virgin Islands. An NRCS geologist used the report for water use

in 1990 as the basis for estimating freshwater use in each

MLRA (Solley and others, 1993). Water use varies annually in

each State, depending on land use patterns, population, and wet
of the United States 3

and dry periods. For example, during a drought, farmers,

ranchers, and other water suppliers will pump more ground

water since surface water may be in short supply. Appendix III

shows the total water use by States in 1980, 1990, and 2000

(Solley and others, 1983; Hutson and others, 2004). In 1980

and 2000, approximately half the States used less water than in

1990 and half used more water than in 1990. An exception was

the amount of surface water used in 1980, which was much

greater than the amount used in either 1990 or 2000. The year

1990 was selected for this handbook because data for that year

were the most recent data available when work on this revision

of the handbook was done. Also, 1990 was not an abnormally

dry or wet year for most States.

Water use by State was apportioned to the different MLRAs

within that State on the basis of the availability of surface and

ground water resources, water quality, and the presence or

absence of users in each MLRA. USGS reports on surface water

sources, quality, and use by State (Moody and others, 1986)

and ground water aquifers, quality, and use by State (Moody

and others, 1988) were used to help apportion State water use to

MLRAs. These reports also contained summaries on water use

in the Pacific Basin and in Puerto Rico and the Virgin Islands.

The section on water in the MLRA descriptions shows the total

amount of surface and ground water used daily, on average, in

each MLRA and the percent of the total used for public supply,

livestock, irrigation, and other purposes. The “other” category

includes municipal and industrial use, cooling of

thermoelectric power plants, mining, domestic use, and any

other miscellaneous water uses. Only the water actually

withdrawn from a stream or other water body is reported in the

MLRA narratives. No in-stream uses, such as generation of

hydroelectric power, are included. MLRAs that depend on other

areas for water supply and those that furnish water to other areas

generally are identified.

Units for the volume of water used are millions of gallons

per day (MGD). MGD is multiplied by 3.785 to obtain millions

of liters per day. One MGD flowing for 1 year equals about

1,120 acre-feet, or 1.38 million cubic meters, of water.

Soils.— The soils described in this publication are classified

and named in accordance with the USDA system of classifying

soils described in Soil Taxonomy (Soil Survey Staff, 1999).

Appendix IV gives a brief description of the soil classification

system. The section on soils in the MLRA descriptions

generally identifies the dominant soil orders in each MLRA,

the major soil temperature and moisture regimes and particlesize and mineralogy classes of the dominant soils, and, for each

soil order listed, one or more of the dominant great groups.

Each of the great groups is identified with a common parent

material and landscape position within the MLRA. Finally, one

or more soil series considered representative of each great

group is listed in parentheses.

This information was derived primarily from the intersection

of Soil Survey Geographic Database (SSURGO) and MLRA

maps. SSURGO coverage is available for most of the MLRAs.

Historic information and State soil survey staffs were consulted

for missing data.

Biological Resources.—The dominant plant species within

each MLRA are identified by their common names. This

information was derived from a wide variety of NRCS and other

agency reports, and specific references are not listed. NRCS

biologists and soil scientists utilized local knowledge to

develop lists of common fish and wildlife species in each

MLRA. Some scientific names had to be included for plants

and animals in the Pacific Basin because of the variety of

languages and dialects used on various islands and the fact that

common names have not been developed. Also, scientific

names had to be used to identify some of the plants in Hawaii.

Land Use.—The relative extent of various kinds of federally

or privately owned land is indicated in the description of each

MLRA. These data generally were derived from the 1997

National Resources Inventory (USDA, 1997). The land use in

Alaska was determined by the State NRCS staff, which

intersected the MLRA map with a locally generated land use

map based on ecoregions (U.S. Department of the Interior,

1973). Land use statistics for Alaska reflect usage across all

lands, both private and Federal. No NRI statistics are available

for the Pacific Basin, so local NRCS soil scientists developed

the land use statistics from local sources. Similarly, soil

scientists in Hawaii utilized recent National Oceanic and

Atmospheric Agency land cover information when developing

land use statistics.

Categories of land use provided by NRI were combined into

cropland, grassland, forest, urban development, water, and

other. “Grassland” includes the NRI categories of pasture,

range, brush, and tundra. Hayland was grouped with cropland.

“Urban development” includes urban areas, built-up areas, and

areas used for transportation. “Other” includes the NRI category

of miscellaneous and barren. For example, rock outcrop and

glaciers are considered to be “barren.” The percent of each

relevant land use category in each MLRA is listed in the

MLRA descriptions. The NRI statistics provide only a total

figure for Federal land by MLRA. These values were returned to

the appropriate States for State personnel to break down into

the various land use categories.

Also included under the heading “Land Use” is a description

of the dominant farming, ranching, or other land use activities

in the MLRA. The principal crops are identified where cropland

is significant, and tree species are listed where logging is the

dominant land use activity.

NRCS natural resource specialists provided descriptions of

some of the major resource management concerns in each

MLRA. They also provided descriptions of some of the

common soil and water conservation practices used to mitigate

the impacts of the resource concerns in each MLRA.
Figure 1: Mean annual precipitation (MAP) for the conterminous United States based on the period 1961-1990.
Figure 2: Mean annual air temperature (MAAT) for the conterminous United States based on the period 1961-1990.
Figure 3: Mean annual precipitation (MAP) for Alaska, for Hawaii, and for Puerto Rico and the Virgin Islands. Only Alaska and Hawaii data are based o

The data for Puerto Rico and the Virgin Islands are from different local weather stations and from different time periods.
Figure 4: Mean annual precipitation (MAP) for the Pacific Basin based on local weather station data from different time periods

9

A—Northwestern Forest, Forage, and

Specialty Crop Region

This region (shown in fig. A-1) is in Oregon (42 percent),

Washington (39 percent), and California (19 percent). It makes

up 90,165 square miles (233,635 square kilometers).

Steep mountains and narrow to broad, gently sloping valleys

and plains characterize this region (fig. A-2). Two major

mountain systems are in this region. One, the Coast Range,

parallels the coast. It is anchored by the Olympic Mountains on

the north and the Klamath Mountains on the south. It consists

primarily of tilted, folded, and faulted sedimentary and

metamorphic rocks. The Cascade Mountains, the other major

mountain system in the region, consist primarily of volcanic

crystalline rocks. The Willamette Valley separates the Coast

Range from the higher Cascade Mountains inland. It is a rich

agricultural area because of a mild coastal climate, high

rainfall, and deep soils that formed in alluvium and glacial

drift. A triple junction of two oceanic plates and one

continental plate is directly offshore from Puget Sound.

Movement between these plates has resulted in major

earthquakes in this area in the past. Subduction of the oceanic

plates under the westerly and northwesterly moving continental

plate contributes to volcanic activity in the Cascades. The

mountains in the Coast Range grade into gently sloping marine

terraces along the Pacific Ocean coast. These terraces are cut by

the many rivers draining this area.

The average annual precipitation ranges from 45 to 60

inches (1,145 to 1,525 millimeters) in much of the region, but it

is 30 to 45 inches (760 to 1,145 millimeters) in the Puget

Sound and Willamette Valley and 9 to 25 inches (230 to 635

millimeters) on the east side of the Cascade Mountains. The

annual precipitation in the mountains is typically more than

100 inches (2,540 millimeters), but it can exceed 250 inches

(6,350 millimeters) on the highest peaks. This region is dry in

summer. The average annual temperature is 45 to 55 degrees F

(7 to 13 degrees C) in most of the region, but it is 37 to 42

degrees F (3 to 5.5 degrees C) in the Cascades and it can be as

low as 32 degrees F (0 degrees C) on the highest peaks. The

freeze-free period is more than 200 days in most of the valleys,

as long as 365 days along the coast in the southern part of the

region, and only 40 to 70 days on mountain slopes.

Surface water and ground water resources are abundant in

Figure A-1: Location of Land Resource Region A.
10 Major Land Resource Areas

Figure A-2: A typical mountain area of Land Resource Region A.

this region. About 78 percent of the total water used in the

region is from surface water sources. About 49 percent of the

water is used for irrigation. Because of the heavily populated

coastal area of the Pacific Northwest, 22 percent of the water is

public supply water and 28 percent is used by industry.

The dominant soil orders in this region are Alfisols,

Andisols, Entisols, Inceptisols, Spodosols, and Ultisols. Soils

on the hilly and steep uplands are mostly Andisols and

Inceptisols. These soils are shallow to very deep and are well

drained. Soils on the marine and glacial outwash terraces are

dominantly Andisols and Spodosols. These soils are shallow or

moderately deep to cemented materials or are deep or very

deep. They are poorly drained to well drained. Entisols and

Inceptisols are on flood plains and estuaries. These soils are

very deep and typically are very poorly drained or poorly

drained. Alfisols and Ultisols are on the mountains slopes. They

are moderately deep or deep and are well drained. Mollisols are

in the Willamette Valley. These soils are moderately deep to

very deep and typically are moderately well drained. Most of

the soils in the region have a mesic soil temperature regime, but

those on mountain slopes typically have a frigid temperature

regime and those at the highest elevations have a cryic

temperature regime. The dominant soil moisture regime in the

region is udic, but xeric and ustic moisture regimes also occur.

Most of the soils formed in colluvium or residuum weathered

from siltstone and sandstone, but some formed in colluvium

weathered from basalt or other volcanic rocks. The soils have a

mixed mineralogy.

About 44 percent of this region is Federal land, mostly in

national forests. The mountains are heavily forested, and timber

production is the major industry. Dairy farming is an important

enterprise in the valleys that receive abundant rainfall. Grain

crops, grass and legume seeds, fruits, and horticultural specialty

crops are grown extensively in the drier valleys. Water erosion

on the steeper slopes and in unprotected orchards, vineyards,

and other areas of specialty crops is a common management

concern. Sediment from logging roads and landings on steep

forested slopes also is a concern. Landslides can occur during

wet periods in the mountains. 
of the United States 11

1—Northern Pacific Coast Range,

Foothills, and Valleys

This area (shown in fig. 1-1) is in Oregon (65 percent) and

Washington (35 percent). This long, narrow MLRA makes up

about 10,295 square miles (26,675 square kilometers). It has no

major towns. U.S. Highways 101, 12, 30, 26, and 20 cross this

area. The area has a small number of Washington and Oregon

State parks. The Siuslaw National Forest is in the part of this

area in Oregon, and a portion of the Olympic National Forest is

in the northern part of the area, in Washington. The Grand

Ronde and Siletz Indian Reservations are in the part of this area

in Oregon.

Physiography

All of this area is within the Pacific Border Province of the

Pacific Mountain System. The Olympic Mountains Section is

in the northern third of the area, in Washington, and the rest of

the area is in the Oregon Coast Range Section. The area is

bounded by the Olympic Mountains on the north and the

Klamath Mountains on the south. Most of the area consists of

hills and low mountains with gentle to steep slopes. The

valleys are mostly narrow and of small extent.

In Washington, elevation ranges from 100 to 2,500 feet (30

to 760 meters); it is mostly 200 feet (60 meters). Elevations are

typically higher in Oregon. Some peaks in the southern end of

the area range to 4,000 feet (1,220 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Oregon-Washington Coastal (1710), 75 percent; Lower

Columbia (1708), 9 percent; Willamette (1709), 8 percent; and

Puget Sound (1711), 8 percent. The Columbia River bisects this

MLRA, and the headwaters for a number of rivers are in this

area.

Geology

The portion of this MLRA in Washington consists primarily

of young Tertiary sedimentary rocks (siltstone and sandstone)

mixed with volcanic rocks of the same age. Also, glacial till and

outwash deposits are in the northern half of the portion of the

area in Washington. The portion of this MLRA in Oregon

consists primarily of sedimentary rocks with some minor

volcanic rocks. In the far southern portion of the area, near the

Klamath Mountains, the sedimentary rocks are older and some

have been metamorphosed.

Climate

The average annual precipitation in this area is 60 to 200

inches (1,525 to 5,080 millimeters), increasing with elevation.

Most of the rainfall occurs as low-intensity, Pacific frontal

storms. Precipitation is evenly distributed throughout fall,

winter, and spring, but summers are cool and dry. Snowfall

occurs in all of the area. The average annual temperature is 40

to 55 degrees F (4 to 13 degrees C), decreasing with elevation.

The freeze-free period averages 200 days and ranges from 150

to 280 days, decreasing with elevation.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 12.4%; ground water, 3.7%

Livestock—surface water, 0.2%; ground water, 0.7%

Irrigation—surface water, 32.5%; ground water, 9.0%

Other—surface water, 21.1%; ground water, 20.4%

The total withdrawals average 320 million gallons per day

(1,210 million liters per day). About 34 percent is from ground

water sources, and 66 percent is from surface water sources.

Precipitation and perennial streams fed by springs provide

abundant surface water for all present needs. This area supplies

Figure 1-1: Location of MLRA 1 in Land Resource Region A.
12 Major Land Resource Areas

water to the adjoining MLRAs at lower elevations that receive

less precipitation.

Surface water quality is generally good for all uses. The

ground water is mainly of good quality. It generally meets the

water-quality standards for most designated uses.

Soils

The dominant soil orders in this MLRA are Andisols,

Inceptisols, and Ultisols. The soils in the area dominantly have

a mesic or frigid soil temperature regime and a udic soil

moisture regime. They are generally shallow to very deep, well

drained, medial, and loamy or clayey and occur on foothills

and mountain slopes and ridges. Hapludands (Slickrock series)

formed in colluvium over residuum. Fulvudands (Boistfort and

Bunker series) formed in colluvium derived from basalt.

Dystrudepts (Bohannon, Preacher, Rinearson, and Blachly

series) formed in colluvium derived from sedimentary rocks,

Eutrudepts (Digger and Umpcoos series) formed in colluvium

and residuum derived from sedimentary rocks, and Palehumults

(Buckpeak and Honeygrove series) formed in colluvium

derived from sedimentary rocks.

Biological Resources

This area supports dense forest stands. Douglas-fir, western

hemlock, and red alder are the most common species. There are

lesser amounts of western red cedar and grand fir. At the higher

elevations, noble fir is an important part of the plant

community. Huckleberry, salal, blackberry, twinflower, vine

maple, bigleaf maple, Pacific yew, thimbleberry, rhododendron,

Oregon-grape, salmonberry, violet, trillium, swordfern,

insideout flower, oxalis, beargrass, and false azalea dominate in

the understory.

Some of the major wildlife species in this area are black

bear, cougar, Roosevelt elk, black-tailed deer, coyote, bobcat,

river otter, beaver, raccoon, skunk, muskrat, rabbit, squirrel,

weasel, chipmunk, bald eagle, spotted owl, marbled murelet,

and Steller’s jay. The species of fish in the area include salmon,

steelhead, and cutthroat trout.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 1%

Grassland—private, 3%

Forest—private, 62%; Federal, 30%

Urban development—private, 2%

Water—private, 1%

Other—private, 1%

Most of the area is densely forested, and timber production is

the major industry. Recreation and wildlife habitat also are

important land uses.

The major soil resource concerns are water erosion, surface

compaction, and sedimentation of streams. The quality of

surface water resources also is a major concern.

Conservation practices on forestland generally include

forest site preparation, forest stand improvement, and forest

trails and landings. These practices help to control surface

compaction, the erosion caused by concentrated flow, and

sediment delivery to streams. 

2—Willamette and Puget Sound Valleys

This area (shown in fig. 2-1) is in Washington (57 percent)

and Oregon (43 percent). It makes up about 12,210 square miles

(31,640 square kilometers). The major cities of Seattle, Tacoma,

Olympia, and Vancouver, Washington, and Portland, Corvallis,

and Eugene, Oregon, are in this MLRA. Interstate 5 extends the

entire length of the area from north to south. Interstate 90 joins

Interstate 5 in Seattle, and Interstate 84 joins it in Portland.

Numerous State parks are throughout the part of this area in

Figure 2-1: Location of MLRA 2 in Land Resource Region A.
of the United States 13

from 165 to 220 days in most of this area. It can be as short as

70 days at the highest elevations and as long as 305 days near

the Puget Sound.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 12.6%; ground water, 11.4%

Livestock—surface water, 0.2%; ground water, 0.3%

Irrigation—surface water, 49.9%; ground water, 4.7%

Other—surface water, 17.7%; ground water, 3.3%

The total withdrawals average 2,560 million gallons per day

(9,690 million liters per day). About 20 percent is from ground

water sources, and 80 percent is from surface water sources.

Seattle and Portland consume most of the public water supply

in Washington and Oregon, respectively. High-value crops are

grown under irrigation in parts of the Willamette Valley, but

rainfall is the source of water for most crops.

Moderate precipitation and abundant streamflow provide

enough water for present needs. Surface water supplies,

however, are often short in the summer, and farms located far

from streams may require supplemental ground water for

irrigation. Some additional surface water is available from the

adjoining mountain ranges if reservoirs are constructed. Surface

water quality is good for all uses. Irrigation return flows may be

high in salts from fertilizers.

Ground water quality in this area generally meets drinking

water standards. Ground water is plentiful in glacial and

alluvial deposits around Seattle, Washington. It is soft water of

good quality. High concentrations of naturally occurring iron

and manganese, however, may exceed the drinking water

standards for some ground water in the Puget Sound area. The

city of Portland, Oregon, obtains some of its drinking water

from wells in the basalt along the Columbia River. The water

from the basalt aquifer is moderately hard and of good quality.

Soils

The dominant soil orders in this MLRA are Alfisols,

Inceptisols, Mollisols, and Ultisols. The soils in the area

dominantly have a mesic soil temperature regime, a xeric soil

moisture regime, and mixed mineralogy. They generally are

moderately deep to very deep, poorly drained to well drained,

and loamy or clayey. Nearly level, somewhat poorly drained

Argialbolls (Amity series), poorly drained Albaqualfs (Dayton

series), and moderately well drained Argixerolls (Woodburn

series) formed in lacustrine sediments on terraces. Somewhat

excessively drained Dystroxerepts (Everett series) formed in

outwash sediments and alluvium on terraces and moraines.

Moderately well drained Dystroxerepts (Alderwood and

Kapowsin series) formed in till on till plains and moraines.

Gently sloping to steep, well drained Haplohumults (Bellpine

Washington, especially south of Puget Sound. A number of

national wildlife refuges are in the Willamette Valley, in

Oregon. The Lummi, Tulalip, and Nisqually Indian

Reservations, McChord Air Force Base, and Fort Lewis are in

the part of this MLRA in Washington.

Physiography

Almost all of this area lies within the Puget Trough Section

of the Pacific Border Province of the Pacific Mountain System.

The lowlands of the Puget Sound are partly submerged, and

major terrace systems flank the Willamette Valley. The western

edge of this area is the Oregon Coast Range of the Pacific

Border Province of the Pacific Mountain System. The Cascade

Mountains border this MLRA on the east, and the Coast Range

and Olympic Mountains border it on the west.

Elevation ranges from sea level to 1,640 feet (500 meters).

The Willamette Valley consists of nearly level to gently sloping

flood plains bordered by higher terraces that are cut by

tributaries of the Willamette River. The Puget Sound Valley

consists of nearly level lacustrine deposits and dissected glacial

till and glacial outwash.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Puget Sound (1711), 45 percent; Willamette (1709), 41 percent;

Lower Columbia (1708), 8 percent; and Oregon-Washington

Coastal (1710), 6 percent. The Columbia River, flowing east to

west, bisects the area. The Willamette River runs down the

middle of the southern half of the area. The Willamette and

Columbia Rivers join in Portland, Oregon.

Geology

Glacial till, glacial outwash, and lacustrine deposits cover

the floor of the Puget Sound Valley. The Willamette Valley is

underlain primarily by alluvium.

Climate

The average annual precipitation is 30 to 60 inches (760 to

1,525 millimeters) in much of the area. Lower annual rainfall,

down to 17 inches (430 millimeters), occurs on the lee side of

the Coast Range Mountains along the western border of this

area. The highest average annual rainfall, 60 to 109 inches

(1,525 to 2,770 millimeters), is in the higher areas along the

eastern border of the MLRA. Most of the rainfall occurs as lowintensity, Pacific frontal storms. Rain turns to snow at the

higher elevations. Precipitation is evenly distributed

throughout fall, winter, and spring, but summers are dry. The

average annual temperature is 42 to 54 degrees F (6 to 12

degrees C). The lower temperatures occur at the higher

elevations on the eastern edge of this area. The average annual

temperature is 50 degrees F (8 degrees C) or more in much of

the area. The freeze-free period averages 190 days and ranges
14 Major Land Resource Areas

3—Olympic and Cascade Mountains

This area (shown in fig. 3-1) is in Oregon (61 percent) and

Washington (39 percent). It makes up about 24,375 square

miles (63,170 square kilometers). It has no major cities.

Interstate 90 crosses the Cascade Mountains in the center of the

and Nekia series) and Palehumults (Jory series) formed in

colluvium and residuum on foothills. Moderately well drained

Vitrixerands (Tokul series) formed in a mixture of till, loess, and

volcanic ash on hills.

Biological Resources

This area supports forest vegetation in many places, prairie

vegetation in some places, and savanna vegetation in others.

Douglas-fir is the dominant tree species. Bigleaf maple, western

red cedar, and grand fir also are common. Red alder is

aggressive on disturbed sites in Washington. Stands of

cottonwoods and willows grow on overflow channels,

streambanks, and islands. Oregon white oak is common in

savannas, especially in Oregon. Red and western fescues,

bromes, and sedges are common in the prairies and savannas.

Forest and savanna understory species include tall Oregongrape, Indian plum, snowberry, hazel, oceanspray, serviceberry,

rose, poison oak, swordfern, dwarf Oregon-grape, and

thimbleberry.

Some of the major wildlife species in this area are blacktailed deer, coyote, bobcat, beaver, rabbit, pheasant, ruffed

grouse, California quail, owls, and woodpeckers.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private,15%

Grassland—private, 10%

Forest—private, 37%; Federal, 3%

Urban development—private, 19%

Water—private, 10%

Other—private, 5%

In the Puget Sound Valley, nearly one-third of the land is

forested and timber production is the major industry. In the

Willamette Valley, less than one-tenth of the land is forested and

timber production is of lesser importance. Urbanization is

increasing in much of the area. Agriculture is highly diversified.

Deciduous fruits, berries, vegetables, seed crops, and grains

grown under intensive management are the major crops. The

acreage used for wine grapes is increasing rapidly, especially in

the Willamette Valley. A large acreage is used for hay or grain

for dairy and poultry feed. High-value crops are grown under

irrigation in some areas, but rainfall is the source of water for

most crops.

The major soil resource concerns are water erosion,

maintenance of the content of organic matter and tilth of the

soils, soil productivity, and sedimentation of streams and road

ditches. The quality of surface and ground water resources also

is a major concern.

Conservation practices on cropland generally include

crop residue management, conservation crop rotations,

waste utilization, nutrient management, pest management,

filter strips, grassed waterways, and irrigation water

management.

Conservation practices on pasture and hayland generally

include prescribed grazing, forage harvest management,

nutrient management, waste utilization, and filter strips.

These practices help to protect water quality and aquatic habitat

for fish and wildlife by reducing the movement of nutrients and

pesticides to surface water and ground water.

Conservation practices on forestland generally include

forest site preparation, forest stand improvement, and forest

trails and landings. These practices help to control surface

compaction, the erosion caused by concentrated flow, and

sediment delivery to streams. 

Figure 3-1: Location of MLRA 3 in Land Resource Region A.
of the United States 15

part of this area in Washington, and Interstate 84 crosses the

area on the border between Washington and Oregon. A major

portion of this MLRA consists of national forests (including the

Olympic, Mt. Baker-Snoqualmie, Gifford Pinchot, Mt. Hood,

Willamette, and Umpqua National Forests) and national parks

(including Olympic, North Cascades, Mt. Rainier, and Crater

Lake). A number of wilderness areas are set aside in the national

forests.

Physiography

The northern one-fourth of this area is in the Northern

Cascade Mountains Section of the Cascade-Sierra Mountains

Province of the Pacific Mountain System. Almost all of the

other areas in this MLRA are in the Middle Cascade Mountains

Section of the Cascade-Sierra Mountains Province of the

Pacific Mountain System. The Olympic Mountains are

included within this MLRA, in the Olympic Mountains

Section of the Pacific Border Province of the Pacific Mountain

System.

 Elevation generally ranges from 660 to 5,600 feet (200 to

1,710 meters), but it is as high as 14,400 feet (4,390 meters) on

mountain peaks. The Cascade Mountains typically have sharp

alpine summits of accordant height and some isolated volcanic

cones. These volcanic peaks rise thousands of feet above the

surrounding mountains. Examples are Mt. Baker, Mt. Rainier,

Mt. Hood, and Mt. Jefferson. The Olympic Mountains are very

similar to the Cascades but do not have the volcanic cones.

Steep mountains, narrow valleys, some U-shaped glaciated

valleys, and narrow divides are dominant in the Olympic

Mountains. Plateaus and narrow bands of flood plains and

terraces border some of the streams.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Puget Sound (1711), 30 percent; Willamette (1709), 23 percent;

Lower Columbia (1708), 16 percent; Upper Columbia (1702),

11 percent; Oregon-Washington Coastal (1710), 8 percent;

Middle Columbia (1707), 8 percent; Yakima (1703), 3 percent;

and Klamath-Northern California Coastal (1801), 2 percent.

The Columbia River bisects this MLRA. This mountainous area

contains the headwaters of numerous rivers in Washington and

Oregon, including the Willamette River.

Geology

The Northern Cascades are made up of a mixture of a

variety of sedimentary rocks on the western slopes and

metamorphic rocks cut by igneous intrusives on the eastern

slopes. South of this northern quarter, the rest of the Cascade

range consists primarily of andesite and basalt flows and some

tuffs. The Olympic Mountains consist of uplifted sedimentary

rocks. Thin deposits of alluvium are at the lower elevations

along the major streams draining the Cascades. All of the

Cascades have been glaciated, and isolated remnants of till and

outwash deposits are at the lower elevations on the flanks of the

mountains.

Climate

The average annual precipitation is 60 to 140 inches (1,525

to 3,555 millimeters) in most of this area and is as much as 280

inches (7,110 millimeters) on Mt. Olympus. Some small areas in

the northeast corner and the southernmost tip of the area

receive only13 to 45 inches (330 to 1,145 millimeters). Most of

the rainfall occurs as low-intensity, Pacific frontal storms during

fall, winter, and spring. Rain turns to snow at the higher

elevations, and all of the area receives snow in winter. The

average annual temperature is 27 to 53 degrees F (-3 to 12

degrees C), decreasing with elevation. The freeze-free period

averages 189 days and ranges from 72 to 307 days. The longest

growing season occurs only in the southernmost part of this

area, and there may be no growing season at all at the highest

elevations. Frost may occur during every month of the year at

the higher elevations.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 12.9%; ground water, 3.9%

Livestock—surface water, 0.1%; ground water, 0.2%

Irrigation—surface water, 3.2%; ground water, 0.7%

Other—surface water, 69.0%; ground water, 10.0%

The total withdrawals average 155 million gallons per day

(585 million liters per day). About 15 percent is from ground

water sources, and 85 percent is from surface water sources.

Precipitation and perennial streams fed by glaciers and springs

provide abundant surface water for all of the present needs in

the area. This area supplies water to the lower lying adjoining

MLRAs that receive less precipitation.

This MLRA has very few aquifers. Columbia River basalt

and basin fill and alluvial aquifers along the Columbia River in

Oregon are the only two extensive aquifers. Ground water is

mainly of good quality. It generally meets the water-quality

standards for most designated uses.

Soils

The dominant soil orders in this MLRA are Andisols,

Inceptisols, Spodosols, and Ultisols. The soils in the area

dominantly have a mesic, frigid, or cryic soil temperature

regime and a udic soil moisture regime. They generally are

moderately deep to very deep, well drained, ashy, medial, and

loamy or clayey and occur on mountain slopes and ridges.

Vitricryands (Castlecrest series) formed in volcanic ash,
16 Major Land Resource Areas

4A—Sitka Spruce Belt

This area (shown in fig. 4A-1) is in Washington (55 percent)

and Oregon (45 percent). It is along the Pacific Ocean coast.

This long, narrow MLRA makes up about 5,305 square miles

(13,740 square kilometers). The major towns in Washington are

Aberdeen, Hoquiam, and Forks. The towns of Astoria,

Tillamook, and Coos Bay, Oregon, are in the southern part of

the MLRA. U.S. Highway 101 follows the coastline in the

southern half of the area. Part of the Olympic National Park is in

the northwest corner of the area, and many Washington and

Oregon State parks are along the coast. The MLRA includes

pumice, and cinders. Some Dystrudepts (Aschoff and Zygore

series), Haploxerands (Cinebar series), and Cryohumods

(Playco series) formed in colluvium mixed with volcanic ash.

Other Dystrudepts formed in colluvium over residuum (Kinney

and Klickitat series) or in colluvium (Blachly series). Shallow

Fulvudands (Dimal series) formed in residuum weathered from

sandstone. Moderately deep Durudands (Elwell series) formed

in till mixed with volcanic ash and loess. Palehumults

(Honeygrove and Olympic series) and moderately deep

Fulvudands (Solleks series) formed in colluvium over residuum

weathered dominantly from sandstone. Haplohumults (Peavine

series) formed in colluvium over residuum weathered from

siltstone and shale. Haplocryods (Nimue series) and

Haplorthods (Pitcher series) formed in colluvium mixed with

volcanic ash over residuum.

Biological Resources

This area supports dense forest stands. Douglas-fir, Pacific

silver fir, and western hemlock are the most common species.

The area has lesser amounts of western red cedar, noble fir,

grand fir, and white fir. At the higher elevations, mountain

hemlock is an important part of the plant community and

subalpine fir and whitebark pine grow near timberlines.

Huckleberry, salal, blackberry, twinflower, vine maple, bigleaf

maple, Pacific yew, thimbleberry, rhododendron, Oregon-grape,

salmonberry, violet, trillium, swordfern, insideout flower,

oxalis, beargrass, and false azalea may occur in the understory.

Some of the major wildlife species in this area are black bear,

cougar, Roosevelt elk, black-tailed deer, coyote, bobcat, river

otter, mountain beaver, raccoon, skunk, opossum, muskrat,

rabbit, squirrel, weasel, chipmunk, bald eagle, osprey, turkey

vulture, pheasant, ruffed and blue grouse, California quail,

Steller’s jay, and meadowlark. The species of fish in the area

include salmon, steelhead, smelt, shad, sturgeon, whitefish,

bass, trout, sunfish, perch, and crappie.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—private, 1%

Forest—private, 27%; Federal, 63%

Urban development—private, 1%

Water—private, 1%; Federal, 6%

Other—private, 1%

Most of the area is densely forested, and timber production is

the major industry. At high elevations, alpine meadows provide

summer range. Mining is important in some areas. Recreation

and wildlife habitat also are important land uses.

The major soil resource concerns are water erosion, surface

compaction, and sedimentation of streams. The quality of

surface water resources also is a major concern.

Conservation practices on forestland generally include

forest site preparation, forest stand improvement, and forest

trails and landings. These practices help to control surface

compaction, the erosion caused by concentrated flow, and

sediment delivery to streams. 

Figure 4A-1: Location of MLRA 4A in Land Resource Region A.
of the United States 17

parts of the Siuslaw and Siskiyou National Forests in Oregon.

Part of the Olympic National Forest is in the far northeast end

of the area. The Quinault, Quileute, Ozette, Hoh, and Makah

Indian Reservations are in the northern part of the area.

Physiography

All of this area is within the Pacific Border Province of the

Pacific Mountain System. Three different physiographic

sections occurring in this area are, from north to south, the

Olympic Mountains Section, the Oregon Coast Range Section,

and the Klamath Mountains Section. Even though all of these

sections are named after mountain ranges, there are actually no

mountains within this coastal area.

In Washington, elevation ranges from sea level to a

maximum of 1,800 feet (550 meters) inland. A cliff 50 to 200

feet (15 to 60 meters) high forms most of the western edge of

the part of this MLRA in Washington. Most of this part of the

MLRA has an elevation of 50 to 300 feet (15 to 90 meters).

From the edge of the cliff, the land slopes up onto glacial drift

deposits, marine terraces, or young, continental sedimentary

rocks in the northern portion. In the southwest corner of

Washington, the land slopes from the edge of the cliff up onto

alluvial or marine terraces or flood plains and beach dunes. The

MLRA is very hilly away from the coast.

The Oregon portion of this MLRA is similar to the portion in

Washington. A rugged cliff 50 to 250 feet (15 to 75 meters)

high forms most of the western edge of the part of this MLRA

in Oregon, and elevations reach 1,800 feet (550 meters) inland

on the area’s eastern boundary. The coastal area around the

mouth of the Columbia River and the flood plains along the

major rivers near the coast are flat, but inland areas are very

hilly. Marine terraces are common along the coast, and the

coast consists of numerous bays, coves, headlands, and

estuaries. The coast is eroding. Isolated rocks and small islands

are directly offshore.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Oregon-Washington Coastal (1710), 89 percent; Lower

Columbia (1708), 7 percent; and Puget Sound (1711), 4

percent. The area is highly dissected by numerous perennial

rivers and creeks. The Columbia River discharges into the

Pacific Ocean in the middle of this MLRA.

Geology

The portion of this MLRA in Washington consists primarily

of glacial and alluvial sediments and some scattered areas of

young Tertiary sedimentary rocks (siltstone). Glacial deposits

are dominant in the northern half of the area, and alluvium and

beach dune deposits are more prominent in the southern half of

the part of the MLRA in Washington. A significant portion of

the part of the MLRA in Oregon consists of marine and

estuarine sediments and some minor sedimentary and volcanic

rocks. At the far southern part of this area, near the Klamath

Mountains, the sedimentary rocks are older and some have been

metamorphosed.

Climate

The average annual precipitation is 52 to 60 inches (1,320 to

1,525 millimeters) near the beach and up to 191 inches (4,850

millimeters) at the higher elevations on the inland edge of the

MLRA. Most of the rainfall occurs as low-intensity, Pacific

frontal storms. Precipitation is evenly distributed throughout

fall, winter, and spring, but summers are cool and dry. Snowfall

accumulation is rare on the ocean side of this area, but some

snowfall occurs on the eastern boundary. This area lies within

the coastal fog belt zone, and heavy fogs are common in

summer. Supplemental moisture is provided by fog

condensation. The average annual temperature is 45 to 55

degrees F (7 to 13 degrees C). The freeze-free period averages

290 days and ranges from 220 to 365 days in most of this area.

The ocean influence on the western edge of this area increases

the length of the freeze-free period, and the period is much

shorter at the higher elevations on the eastern edge of the area.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 44.3%; ground water, 21.2%

Livestock—surface water, 0.3%; ground water, 0.1%

Irrigation—surface water, 2.7%; ground water, 0.0%

Other—surface water, 30.3%; ground water, 1.1%

The total withdrawals average 56 million gallons per day

(210 million liters per day). About 22 percent is from ground

water sources, and 78 percent is from surface water sources.

Abundant precipitation and many perennial streams provide

enough water for most needs. Rainfall is the source of water for

most crops, but some high-value crops are grown under

irrigation on the coastal flats and on the flood plains a short

distance inland from the mouths of the major rivers. The drier

valleys depend on streamflow from the mountains. The surface

water supply is often short in summer, and farms located far

from streams may require supplemental ground water for

irrigation. Surface water quality is generally good for all uses.

Ground water is plentiful in alluvial, glacial outwash, terrace,

and beach dune deposits. It is soft water, and it generally meets

drinking water standards, except for naturally occurring levels

of iron and manganese in the northern part of the area.

Soils

The dominant soil orders in the MLRA are Andisols,

Inceptisols, Spodosols, and Entisols. The soils have either an

isomesic or isofrigid soil temperature regime. They have a udic
18 Major Land Resource Areas

or perudic soil moisture regime. They are acid throughout; most

are very strongly acid or strongly acid. The hilly to extremely

steep uplands are dominated by Andisols and Inceptisols. These

soils are shallow to very deep and are well drained. They have

ferrihydritic or isotic mineralogy. Fulvudands (Solleks,

Necanicum, Lytell, and Tolovana series) and Dystrudepts

(Templeton series) dominate the uplands. The undulating to

hilly marine and glacial outwash terraces are dominated by

Andisols and Spodosols. These soils are shallow or moderately

deep to cemented materials or are deep or very deep. They are

poorly drained to well drained. They have ferrihydritic or isotic

mineralogy. Fulvudands (Lint and Mopang series), Durudands

(Hoko series), Placaquands (Halbert series), Haplorthods

(Netarts and Yaquina series), and Duraquods (Depoe series)

dominate the terraces. The soils on the nearly level flood plains

and in the estuaries are primarily Entisols and Inceptisols with

minor areas of Histosols. These soils are very deep and

typically are very poorly drained or poorly drained. They have

mixed mineralogy. Fluvaquents (Coquille and Ocosta series),

Humaquepts (Brenner and Clatsop series), Udifluvents

(Grehalem series), Dystrudepts (Nehalem series), and

Haplohemists (Brallier series) dominate the flood plains and

estuaries.

Biological Resources

This area is highly diverse in flora and fauna. Its eastward

extent is coincident with the extent of plant communities

dominated by Sitka spruce. The uplands are dominated by a

dense overstory of Sitka spruce, western hemlock, western red

cedar, red alder, and Douglas-fir. Their understory is dominated

by salal, western swordfern, huckleberry, and oxalis. The

terraces have shore pine as a dominant overstory species in

addition to the species on uplands. The flood plains and

estuaries are dominated by saltgrass, skunk cabbage, tussock

and other sedges, and reeds. During periods of low tide, large

nonvegetated mudflats are exposed in the coastal bays.

Some of the major wildlife species in this area are black bear,

Roosevelt elk, black-tailed deer, coyote, fox, bobcat, beaver,

otter, raccoon, skunk, muskrat, opossum, rabbit, squirrel, mink,

wood rat, bald eagle, osprey, crow, ruffed grouse, blue grouse,

raven, merganser, kingfisher, band-tailed pigeon, and the

endangered spotted owl and marbled murelet. Salamanders,

newts, and slugs are common in the decomposing forest litter.

The tidal estuaries are habitat for clams, crabs, and salmonids.

The species of fish in the area include salmon, steelhead trout,

white sturgeon, Columbia River smelt, and cutthroat trout. The

rivers and bays in this area are important spawning grounds and

habitat for steelhead, salmon, and cutthroat trout.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—private, 4%

Forest—private, 68%; Federal, 11%

Urban development—private, 5%

Water—private, 8%

Other—private, 4%

Most of this area consists of privately owned farms, ranches,

or forests. Lumbering is the major industry. A small acreage in

the area is grassland used for grazing. Less than 1 percent of the

area is cultivated land, which is used mainly for forage and

grain for dairy cattle. Although the freeze-free period is long,

the area lacks the heat units necessary for the maturation of

most crops. Vegetables and fruits (apples) are grown in areas

where the soils and climate are favorable. Specialty crops, such

as cranberries and lily bulbs, also are grown in the area.

The major soil resource concerns are water erosion and its

subsequent deposition of sediment into the rivers and creeks.

Soils in basins and on flood plains are susceptible to flooding,

deposition of sediments, and local streambank cutting. The

hazard of erosion is moderate on terraces and coastal benches.

Erosion can be severe if the vegetative cover on the upland soils

is removed by logging, fire, overgrazing, or cultivation.

Landslides in the uplands are a source of sediment.

Conservation practices on forestland generally include forest

site preparation, forest stand improvement, and forest trails and

landings. These practices help to control surface compaction,

the erosion caused by concentrated flow, and sediment delivery

to streams. Maintaining a vegetative cover or forest litter over

the mineral soil surface helps to control runoff and erosion.

Conservation practices on cropland are nutrient management

and measures that reduce the hazard of erosion. 
of the United States 19

Figure 4B-1: Location of MLRA 4B in Land Resource Region A.

4B—Coastal Redwood Belt

This area (shown in fig. 4B-1) is primarily in California (98

percent). A small part of the area is in Oregon (2 percent). This

MLRA makes up about 4,670 square miles (12,095 square

kilometers). The towns of Crescent City, Arcata, Eureka, and

Fort Bragg, California, and Brookings, Oregon, are in this

MLRA. U. S. Highway 101 parallels the coastline in the

northern half of the area. Redwood National Park, King Range

National Conservation Area (BLM), and numerous California

State parks are in this MLRA.

Physiography

The northern one-third of this area lies within the Klamath

Mountains Section of the Pacific Border Province of the Pacific

Mountain System. The rest of the area is in the California Coast

Ranges Section of the Pacific Border Province of the Pacific

Mountain System. The Klamath Mountains are an uplifted

peneplain consisting of resistant rocks that have been eroded by

numerous streams. Numerous peaks of erosion-resistant rock are

in these low mountains. The California Coast Ranges consist of

parallel ranges and valleys underlain by folded and faulted

metamorphic rocks. Their peaks are rounded, and landslides are

a dominant geomorphic process.

Elevation generally ranges from sea level to 2,600 feet (795

meters), but on some Coast Range peaks it is 3,940 feet (1,200

meters). The Pacific Ocean bounds this area on the west, and the

Coast Range forms the eastern edge. The MLRA is an area of

steep mountainous terrain. Low but steeply sloping mountains

are dominant. Gently sloping marine terraces border the coast,

and a few broad valleys extend inland through the mountains.

This area is very hilly inland. Most of the coast is a rugged,

steep mountain face 200 to 900 feet (60 to 275 meters) high.

Beaches occur at the mouth of rivers. The coast is eroding, and

some isolated rocks and small islands are directly offshore.

The extent of the major Hydrologic Unit Areas (identified

by four-digit numbers) that make up this MLRA is as follows:

Klamath-Northern California Coastal (1801), 83 percent;

Central California Coastal (1806), 8 percent; San Francisco

Bay (1805), 7 percent; and Oregon-Washington Coastal

(1710), 2 percent. The Smith, Klamath, Mad, Eel, Mattole,

Noyo, Navarro, Chetco, Winchuck, and Garcia Rivers and

Redwood Creek discharge into the Pacific Ocean from this

area.

Geology

The mountains in this MLRA consist primarily of contorted

metamorphic rocks. Some igneous intrusives are in the Klamath

Mountains. Serpentine is evident in many of the metamorphic

units, and failure planes in landslides are common within the

serpentine layers. Changes in sea level created marine terraces

along the coast. The terraces consist of sand and gravel

originally deposited as beach or alluvial fan deposits at the

mouth of the major rivers.

Climate

The average annual precipitation in this area is 23 to 98

inches (585 to 2,490 millimeters), increasing with elevation

inland. Most of the rainfall occurs as low-intensity, Pacific

frontal storms. Precipitation is evenly distributed throughout

fall, winter, and spring, but summers are dry. Snowfall is rare

along the coast, but snow accumulates at the higher elevations

directly inland. Heavy fogs are common along the coast in

summer. The average annual temperature is 49 to 59 degrees F

(10 to 15 degrees C). The freeze-free period averages 300 days

and ranges from 230 to 365 days, decreasing inland as elevation

increases.
20 Major Land Resource Areas

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 1.6%; ground water, 0.5%

Livestock—surface water, 0.1%; ground water, 0.0%

Irrigation—surface water, 77.5%; ground water, 15.5%

Other—surface water, 4.4%; ground water, 0.4%

The total withdrawals average 32 million gallons per day

(120 million liters per day). About 16 percent is from ground

water sources, and 84 percent is from surface water sources.

Abundant precipitation and many perennial streams provide

enough water for most needs. Rainfall is the source of water for

most crops, but some high-value crops, such as lily bulbs, are

grown under irrigation on the coastal terraces and on the flood

plains a short distance inland from the mouth of the major

rivers. The drier valleys depend on streamflow from the

mountains. The surface water supply is often short in summer,

and farms located far from streams may require supplemental

ground water for irrigation. Surface water quality is generally

good for all uses.

Ground water is plentiful in alluvial deposits along the major

rivers and in coastal valleys. It is moderately hard or hard water

of generally good quality and is suitable for most uses.

Soils

The dominant soil orders in the MLRA are Alfisols, Entisols,

Inceptisols, and Ultisols. The soils dominantly have an

isomesic or mesic soil temperature regime; a udic, xeric, or

ustic soil moisture regime; and mixed mineralogy. They

generally are deep or very deep, well drained, and loamy or

clayey and occur on mountain slopes and hills in addition to

coastal terraces. The dominant parent material is residuum

weathered from sandstone. The soils of dominant extent

include Hapludalfs (Dehaven and Irmulco series),

Dystroxerepts (Hugo series), Haplohumults (Vandamme,

Winchuck, and Loeb series), Dystrudepts (Dulandy series),

Haploxerults (Josephine series), and Haplustalfs (Kibesillah,

Ornbaun, Yellowhound, and Zeni series). The soils on flood

plains are Udifluvents (Bigriver and Cottoneva series).

Biological Resources

This area supports forest and grass vegetation. Redwood,

Douglas-fir, grand fir, bishop pine, western red cedar, PortOrford cedar, red alder, California bay laurel, golden chinkapin,

Pacific madrone, tanoak, Sitka spruce, and California black oak

are the dominant tree species. California oatgrass, tufted

hairgrass, western and Idaho fescues, Pacific reedgrass, and

native and introduced bentgrasses are common perennial

grasses. Soft chess, wild oats, bromes, filaree, and burclover are

important naturalized annuals. Gorse-broom and Scotch-broom

are dominant in some parts of the coastal zone.

Some of the major wildlife species in this area are blacktailed deer, coyote, gray fox, raccoon, muskrat, river otter,

rabbit, squirrel, mink, turkey, blue grouse, California valley

quail, band-tailed pigeon, and mourning dove. The species of

fish in the area include bluegill, redear, black bass, crappie,

catfish, steelhead, salmon, striped bass, rainbow trout, surf

perch, tom cod, and sculpin.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 4%

Grassland—private, 14%

Forest—private, 60%; Federal, 12%

Urban development—private, 7%

Water—private, 2%

Other—private, 1%

Most of this area consists of privately owned farms, ranches,

or forests. Lumbering is the major industry. About 14 percent of

the area is grassland used for grazing. Cultivated land is in the

valleys and along the coast. It is used mainly for forage and

grain for dairy cattle. Vegetables, fruits (apples), and lily bulbs

are grown in areas where the soils and climate are favorable.

Because of steep slopes, erodible soils, and high rainfall, the

major soil resource concern on uplands is erosion. The erosion

hazard is severe if the plant cover is removed. Mass movement

in the form of landslides and slips is a serious problem and a

major source of sediment in the rivers. Older or improperly

designed roads also contribute sediment. Other management

concerns include compaction resulting from farming activities,

impacts on the health of forestland, such as catastrophic

wildfire, and maintenance of the content of organic matter in

the soils.

Conservation practices on forestland generally include tree

and shrub establishment, forest stand improvement, forest

harvest trails and landings, critical area planting, and control of

understory fuels. These practices improve forest health and

reduce the impacts on wildlife. They also control erosion on

access roads and protect riparian areas and fish habitat.

Conservation practices on rangeland and other grazing land

generally include prescribed grazing, fencing, and water

management.

Conservation practices on cropland generally include those

activities that keep erosion within acceptable limits in the fields

while protecting riparian areas and reducing the hazard of

streambank erosion. Conservation practices on dairy farms

generally include the proper containment and disposal of

animal waste. 
of the United States 21

Figure 5-1: Location of MLRA 5 in Land Resource Region A.

5—Siskiyou-Trinity Area

This area (shown in fig. 5-1) is in California (62 percent) and

Oregon (38 percent). It makes up about 20,150 square miles

(52,215 square kilometers). The towns of Grants Pass, Medford,

and Roseburg, Oregon, and Weaverville, California, are in this

area. Interstate 5 crosses the northeast corner of the area, in

Oregon. Many national forests, including the Umpqua, Rogue

River, Siskiyou, Six Rivers, Klamath, Trinity, Shasta, and

Mendocino National Forests, are in this area. National

wilderness areas occur within almost all the national forests.

The Hoopa Valley and Round Valley Indian Reservations are in

this MLRA.

Physiography

The eastern half of the northern third of this area is in the

Middle Cascade Mountains Section of the Cascade-Sierra

Mountains Province of the Pacific Mountain System. This

section is an area of steep mountainous terrain with generally

accordant summits interspersed with higher volcanic cones.

The Klamath Mountains Section of the Pacific Border Province

of the Pacific Mountain System forms the western half of the

northern third of this MLRA and also makes up most of the

remaining area to the south. This section consists of an

uplifted and eroded peneplain on very hard rocks. Numerous

higher peaks are in scattered areas throughout this

mountainous region. The “Trinity Alps” and “Marble

Mountains” are in this province. The southeast portion of

this MLRA is in the California Coast Ranges Section of

the Pacific Border Province of the Pacific Mountain System.

This section consists of parallel ranges and valleys underlain

by folded and faulted metamorphic rocks. In this section, peaks

are rounded and landslides are a dominant geomorphic

process.

Elevation generally ranges from 330 to 6,000 feet (100 to

1,830 meters), but on some mountain peaks it is 8,850 feet

(2,700 meters). Rounded but steeply sloping mountains are

dominant. These mountains are underlain mainly by sandstone

and shale. In some areas, however, the mountains are underlain

by granodiorite, gabbro, and other intrusive rocks. The narrow

valleys have gently sloping flood plains and alluvial fans and

are bordered by strongly sloping foothills.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Klamath-Northern California Coastal (1801), 55 percent;

Oregon-Washington Coastal (1710), 37 percent; and

Sacramento (1802), 8 percent. The Rogue River in Oregon and

the Eel, Trinity, and Klamath Rivers in California are the largest

rivers in this MLRA. Reaches of the Rogue, Illinois, Smith,

Klamath, Salmon, and Eel Rivers are designated as Wild and

Scenic Rivers in this area.

Geology

Most of this area consists of Mesozoic, marine sandstones

and shales. In some areas granodiorite, gabbro, and other

intrusive rocks of the same age are dominant. Mesozoic

ultramafic rocks also are included in this area. All of these rocks

have been metamorphosed to some extent. An extensive area of

older Paleozoic marine sediments occurs in the south half of

this area. These marine sediments are cut by the Mesozoic

volcanics common in the north. The rocks in the south have

also been strongly metamorphosed.

Climate

The average annual precipitation is 14 to 20 inches (355 to

510 millimeters) at the lower elevations and as much as 200

inches (5,080 millimeters) in the mountains. Most of the

rainfall occurs as low-intensity, Pacific frontal storms. Rain

turns to snow at the higher elevations. Very little precipitation

occurs in summer. Most of the precipitation occurs between

November and April. The average annual temperature is 40 to
22 Major Land Resource Areas

62 degrees F (5 to 17 degrees C), decreasing with elevation.

The freeze-free period averages 240 days and ranges from 110

to 365 days. The shorter freeze-free periods occur at the higher

elevations.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 8.6%; ground water, 8.8%

Livestock—surface water, 0.6%; ground water, 0.5%

Irrigation—surface water, 27.2%; ground water, 13.1%

Other—surface water, 38.4%; ground water, 2.7%

The total withdrawals average 150 million gallons per day

(565 million liters per day). About 25 percent is from ground

water sources, and 75 percent is from surface water sources. The

moderate to high precipitation provides enough water in the

mountains and higher valleys for most needs. The mountains

also supply irrigation water for the lower, drier valleys. The

surface water is suitable for almost all uses.

There are no major aquifers in the Klamath Mountains or the

Coast Range. Ground water is abundant, however, in alluvial

deposits in most valleys. The surface and ground water

generally meets the recommended standards for all uses.

Soils

The dominant soil orders in this MLRA are Alfisols,

Inceptisols, and Ultisols. Xerolls are of minor extent on the

grasslands. The soils in the area dominantly have a mesic soil

temperature regime, a xeric soil moisture regime, and mixed

mineralogy. They generally are moderately deep or deep, well

drained, and loamy and occur on mountain slopes and hills.

Dystroxerepts (Beekman, Neuns, and Sheetiron series) formed

in colluvium or in colluvium over residuum. Shallow

Dystroxerepts (Maymen and Vermisa series) formed in

residuum. Haploxeralfs (Casabonne, Hopland, Sanhedrin,

Speaker, and Vannoy series) and Haploxerults (Josephine series)

formed in colluvium over residuum. Argixerolls and

Haploxerolls (McNull, McMullin, Medco, and Yorktree series)

formed in colluvium and residuum on low hills.

Biological Resources

This area supports forest, open forest, and grassland

vegetation. Douglas-fir, ponderosa pine, sugar pine, incensecedar, white fir, red fir, tanoak, Oregon white oak, California

black oak, canyon live oak, and Pacific madrone are the

dominant tree species. Poison-oak, snowberry, ceanothus,

manzanita, and rose characterize the forest understory. Blue

wildrye, fescues, bluegrass, mountain brome, and some browse

species are in the understory in open stands of timber. Soft

chess, wild oats, burclover, fescues, and bromes are the major

grassland species.

Some of the major wildlife species in this area include

amphibians and reptiles along with black bear, mountain lion,

mule deer, black-tailed deer, coyote, fox, raccoon, ring-tailed

cat, porcupine, skunk, mink, squirrel, grouse, northern spotted

owl, band-tailed pigeon, mountain quail, and California valley

quail. The species of fish in the area include coho and king

salmon, steelhead, and trout.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private,1%

Grassland—private, 6%; Federal, 4%

Forest—private, 34%; Federal, 50%

Urban development—private, 2%

Water—private, 1%; Federal, 1%

Other—private, 1%

Most of this area is in coniferous forests that are important

for wood products, wildlife habitat, and recreation. About onetenth of the area is grazed, and a smaller acreage is cropped.

The raising of livestock is the principal farm enterprise.

Irrigated pasture, hay crops, and some truck crops are grown in

the valleys where water is available. On the more sloping parts

of the valleys, hay and pasture are grown as feed for livestock.

Because of steep slopes, erodible soils, and high rainfall,

the major soil resource concern on uplands is erosion. The

erosion hazard is severe if the plant cover is removed. Mass

movement in the form of landslides and slips is a serious

problem and a major source of sediment in the rivers. Older

or improperly designed roads also contribute sediment.

Other concerns include compaction from farming activities,

impacts on the health of forestland, such as catastrophic

wildfire, and maintenance of the content of organic matter in

the soils.

Conservation practices on forestland generally include tree

and shrub establishment, forest stand improvement, forest

harvest trails and landings, critical area planting, and control of

understory fuels. These practices improve forest health and

reduce the impacts on wildlife. They also control erosion on

access roads, protect riparian areas, and improve the habitat for

fish.

Conservation practices on rangeland and other grazing land

generally include prescribed grazing, fencing, and water

management. Conservation practices on cropland generally

include irrigation water management and nutrient management.

The cropland and grazing land practices help to keep erosion

within acceptable limits in the fields, protect riparian areas, and

reduce the hazard of streambank erosion. 
of the United States 23

6—Cascade Mountains, Eastern Slope

This area (shown in fig. 6-1) is in Oregon (52 percent) and

Washington (48 percent). It makes up about 13,160 square

miles (34,100 square kilometers). The only major town

occurring in the part of this MLRA in Washington is

Leavenworth. Bend, Oregon, is on the exteme eastern edge of

the southern part of the area. The town of The Dalles, Oregon, is

directly east of where the area crosses the Columbia River.

Interstate 84, along the south bank of the Columbia River,

crosses the center of the MLRA, and Interstate 90 crosses the

northern half. Parts of many national forests occur in this area,

including the Okanogan, Wenatchee, Snoqualmie, Gifford

Pinchot, Mount Hood, Deschutes, Winema, and Fremont

National Forests. The Yakama Indian Reservation and the Warm

Springs Indian Reservation are in the area.

Physiography

About half of this MLRA, mostly south of the Columbia

River in Oregon, is in the Walla Walla Plateau Section of the

Columbia Plateaus Province of the Intermontane Plateaus. The

southernmost tip of the MLRA is in the Great Basin Section of

the Basin and Range Province of the Intermontane Plateaus.

The Harney Section of the Columbia Plateaus Province lies

between the Walla Walla Plateau and Great Basin Sections in

the southern end of this area. In Washington, almost all of this

MLRA is in the Northern Cascade Mountains and Middle

Cascade Mountains Sections of the Cascade-Sierra Mountains

of the Pacific Mountain System. This mountainous area

consists of sharp alpine summits of accordant height with some

higher volcanic cones. The Cascade Mountains, Eastern Slope,

is a transitional area between the Cascade Mountains to the

west and the lower lying Columbia Basalt Plateau to the east. It

has some of the landforms typical of both the mountains and

the plateau.

Elevations in this MLRA generally range from 900 to 8,000

feet (275 to 2,440 meters). Some mountain peaks approach

10,000 feet (3,050 meters) in elevation. Strongly sloping

mountains and U-shaped glaciated valleys are dominant in the

north, and eroded basalt plateaus are more typical in the south.

A few isolated volcanic peaks occur in the Harney and Great

Basin Sections in the south. Many streams dissect the gently

sloping crests and benches in the plateau sections.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Middle Columbia (1707), 39 percent; Upper Columbia (1702),

22 percent; Klamath-Northern California (1801), 17 percent;

Yakima (1703), 14 percent; and Oregon Closed Basins (1712),

8 percent. The Columbia River separates the north and south

parts of this MLRA, and the headwaters of a few central

Washington and Oregon streams occur in the area.

Geology

The northern half of this MLRA consists of Pre-Cretaceous

metamorphic rocks cut by younger igneous intrusives. Tilted

blocks of marine shale, carbonate, and other sediments occur in

the far north, and some younger continental, river-laid

sediments occur around Leavenworth, Washington. Columbia

River basalt is dominant in the rest of the MLRA in both

Washington and Oregon. The southern part of the area, south of

Bend, Oregon, is blanketed by a very thick deposit of ash and

pumice from the eruption of Mount Mazama, commonly known

as Crater Lake. Isolated remnants of continental sediments

occur within the expanse of basalt and andesite flows that make

up the southern extent of the Cascade Range. Alpine glaciation

has left remnants of glacial till, debris, and outwash in the

northern part of this MLRA.

Climate

The average annual precipitation in most of this area is 12 to

87 inches (305 to 2,210 millimeters), generally increasing with

elevation to the west. The lowest rainfall occurs along the

Figure 6-1: Location of MLRA 6 in Land Resource Region A.
24 Major Land Resource Areas

eastern edge of the area, away from the mountains, where 12 to

15 inches per year (305 to 380 millimeters) is typical. The

central parts receive 15 to 45 inches per year (380 to 1,145

millimeters). Some mountain crests receive 100 inches (2,540

millimeters) or more of precipitation in an average year. Most of

the rainfall occurs as low-intensity, Pacific frontal storms during

winter, spring, and fall. Rain turns to snow at the higher

elevations. All areas receive snow in winter. Summers are

relatively dry. The average annual temperature is 32 to 53

degrees F (0 to 12 degrees C), decreasing with elevation. The

freeze-free period averages 145 days and ranges from 0 to 250

days. The shortest freeze-free periods occur along the western

edge and the northern and southern ends of this MLRA, which

are mountainous. The longest freeze-free periods occur in the

central part of the area, along the Columbia River gorge. Away

from these areas of extremes, the freeze-free period averages 70

days and ranges from 40 to 140 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 7.4%; ground water, 7.1%

Livestock—surface water, 0.5%; ground water, 0.7%

Irrigation—surface water, 26.6%; ground water, 9.7%

Other—surface water, 36.6%; ground water, 11.3%

The total withdrawals average 205 million gallons per day

(775 million liters per day). About 29 percent is from ground

water sources, and 71 percent is from surface water sources.

Precipitation and perennial streams provide ample surface

water. Perennial streams and reservoirs supply water to the drier

and lower lying MLRAs to the east. Surface water runoff is

dominated by snowmelt, and water quality is good to excellent.

Almost all of the northern half and the west half of the

southern half of this MLRA consist of rock units that are not

aquifers. Most of the supplies of ground water are untapped.

Irrigation water for cropland on valley floors can be pumped

from river alluvium in Washington and from alluvium and

basin fill deposits in Oregon. The Grand Ronde and Wanapum

aquifers are in the Columbia River basalt aquifer in Washington,

directly north of the Columbia River. The basalt aquifer

consists of five different units in Oregon, directly south of the

Columbia River. Most of the southern half of this MLRA is

underlain by the volcanic and sedimentary aquifer group in

Oregon. Ground water is of good quality and has low levels of

dissolved solids. The basalt aquifers provide hard or

moderately hard water.

Soils

The dominant soil orders in this MLRA are Alfisols,

Andisols, Inceptisols, and Mollisols. The Andisols and

Inceptisols in this area are similar to the soils to the west, and

the Mollisols in the area are more typical of the soils to the east.

The soils in the MLRA dominantly have a mesic, frigid, or

cryic soil temperature regime, a xeric soil moisture regime, and

mixed or glassy mineralogy. They generally are moderately

deep to very deep, well drained, and loamy or ashy.

Haploxerolls formed in till (Newbon series) or in till with a

loess or ash mantle (Conconully series). They are on ground

moraines and foothills. Haploxerepts formed in residuum and

colluvium on mountain slopes and ridges (Jumpe series) and in

a mixture of ash and loess over alluvium or colluvium on

uplands (Wamic series). Vitricryands formed in ash and pumice

(Lapine series), ash (Steiger series), and ash over loamy

material (Shanahan series) on plateaus. Vitricryands (Naxing

series) and Vitrixerands (Smiling series) formed in colluvium

mixed with loess and ash. They are on mountain slopes.

Moderately deep Vitrixerands (Maset series) formed in ash over

residuum on benches and hills. Haploxeralfs (Nard and

Underwood series) formed in residuum and colluvium with an

ash mantle. They are on terraces and uplands.

Biological Resources

This area supports conifer forest and grass vegetation. The

kind of vegetation gradually changes with increases in elevation

and in precipitation. Important species on grasslands at the

lowest elevations are bluebunch wheatgrass, Sandberg

bluegrass, big sagebrush, antelope bitterbrush, Idaho fescue,

and Cusick bluegrass. The dominant tree species in the forested

areas are ponderosa pine, Douglas-fir, grand fir, white fir,

western larch, and lodgepole pine. Pacific silver fir, subalpine

fir, and whitebark pine are at the highest elevations. Understory

species include vine maple, hazel, snowberry, oceanspray,

antelope bitterbrush, and green manzanita.

Some of the major wildlife species in this area are bear, elk,

deer, coyote, bobcat, rabbit, turkey, pheasant, Hungarian and

chukar partridge, blue grouse, California quail, dove, and

songbirds. The fish in the area include several species of trout

and salmon.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 2%

Grassland—private, 8%; Federal, 2%

Forest—private, 40%; Federal, 45%

Urban development—private, 1%

Water—private, 1%

Other—private, 1%

About one-half of this area is in privately owned farms,

ranches, or woodland. Most of the area is coniferous forest.

Timber production is an important industry. About one-tenth of

the area supports grasses and is used for grazing. Some of the

woodland is grazed by cattle. Recreation and wildlife habitat
of the United States 25

also are important land uses. A very small area in the valleys is

cropland, most of which is irrigated. Crops include tree fruits,

small grains, and forage crops.

The major soil resource concerns are wind erosion and water

erosion, surface compaction, sedimentation of streams and road

ditches, and maintenance of the content of organic matter and

tilth in the soils. The quality of surface water also is a concern.

Conservation practices on forestland generally include

forest site preparation, forest stand improvement, and forest

trails and landings. These practices help to control surface

compaction, the erosion caused by concentrated flow, and

sediment delivery to streams.

Conservation practices on cropland are those that help to

control erosion and protect water quality. They generally

include cover crops, conservation crop rotations, crop residue

management, waste utilization, nutrient management, pest

management, filter strips, grassed waterways, and irrigation

water management.

Conservation practices on pasture and hayland generally

include prescribed grazing, forage harvest management,

nutrient management, waste utilization, and filter strips. These

practices protect water quality and aquatic habitat for fish and

wildlife by reducing the movement of nutrients and pesticides

to surface water and ground water. 

27

Figure B-1: Location of Land Resource Region B.

B—Northwestern Wheat and Range

Region

This region (shown in fig. B-1) is in Idaho (44 percent),

Washington (29 percent), and Oregon (27 percent). A very small

part is in Utah. The region makes up 81,255 square miles

(210,555 square kilometers).

This region is on the lee side of the Cascade Mountains in

Washington and Oregon and extends east into Idaho along the

Snake River Plains. It is an area of smooth to deeply dissected

plains and plateaus. Well developed terraces are along the

Snake River. Most of this region is underlain by Miocene-age

basalt flows from the Columbia and Idaho Batholiths. The

basalt is covered with a veneer of loess and volcanic ash in

most areas. The region has a few isolated mountain ranges.

The average annual precipitation is 6 to 20 inches (150 to

510 millimeters) in most of the region. It is lowest in the

Columbia Basin area in central Washington and in valleys in

Oregon, in southeastern Idaho, and south of the Snake River in

Idaho. The average annual precipitation can be as much as 45

to 85 inches (1,145 to 2,160 millimeters) in the mountains.

Summers are dry. The average temperature is 40 to 49 degrees F

(5 to 10 degrees C) in most of the region, but it ranges from 30

to 55 degrees F (-1 to 13 degrees C). In most areas the freezefree period averages 160 days and ranges from 125 to 220 days.

It is typically 40 to 70 days in the mountains.

The total withdrawals of freshwater in this region average

53,715 million gallons per day (203,310 million liters per day).

This region uses the largest amount of water among all of the

land resource regions. Surface water is abundant throughout

most of the region. About 72 percent of the total water used in

the region is from surface water sources. The Snake and

Columbia River systems provide almost all of the surface water.

Irrigation is the largest use of water in the region (91 percent).

Ground water is obtained from basalt aquifers and from

alluvium in river valleys.

The dominant soil orders in the region are Mollisols and

Aridisols. Other soil orders that occur in the region are Alfisols,

Andisols, Entisols, and Inceptisols. Mollisols and Aridisols

formed in a deep mixture of loess and ash deposits overlying

the basalt flows in this region. The other soil orders formed in

alluvium on terraces and flood plains or in residuum and

colluvium on foothills and mountain slopes. Most of the soils
28 Major Land Resource Areas

are deep or very deep, well drained, and loamy. They generally

have a mesic or frigid soil temperature regime but have a cryic

temperature regime in the mountains. Almost all of the soils

have a xeric or aridic soil moisture regime.

This region is primarily a mixture of grazing land and

cropland. A few very small areas are forested. About 29 percent

of the land is federally owned grazing land. Wheat grown by

dry farming methods is the major crop in the region, but oats,

barley, lentils, and peas (fig. B-2) also are important. Fruits,

mainly apples, are a major crop in the western part of the

region. Potatoes, sugar beets, beans, and forage crops are grown

under irrigation in the central Columbia basin in Washington

and along the Snake River in Idaho. A variety of specialty crops

are grown in local areas, including vegetables, vegetable seeds,

mint, and hops. Grazing is the major land use in the drier parts

of the region. Water erosion, wind erosion, surface compaction,

maintenance of the content of organic matter and tilth in the

soils, and conservation of soil moisture are major resource

management concerns on cropland. Overgrazing and invasion

of undesirable plant species are resource management concerns

on grazing lands. 

Figure B-2: A field of peas on the rolling hills of the Palouse Area in the northern part of Land Resource Region B.
of the United States 29

Figure 7-1: Location of MLRA 7 in Land Resource Region B.

7—Columbia Basin

This area (shown in fig.7-1) is in Washington (78 percent)

and Oregon (22 percent). It makes up about 6,610 square miles

(17,130 square kilometers). The towns of Yakima, Pasco,

Kennewick, Richland, and Ephrata, Washington, and

Hermiston, Oregon, are in this MLRA. Interstate 90 bisects the

northern half of the MLRA, and Interstate 84 follows the south

side of the Columbia River until it turns east to Pendleton.

Interstate 82 connects Interstates 90 and 84, following the

Yakima River for most of its length. Many State and national

wildlife refuges occur in this MLRA. The Larson Air Force

Base, the Hanford Atomic Energy Reservation, the Umatilla

Army Depot, and the Boardman Bombing Range also are in the

MLRA.

Physiography

This MLRA is in the Walla Walla Plateau Section of the

Columbia Plateaus Province of the Intermontane Plateaus.

Elevation ranges from 300 to 2,000 feet (90 to 610 meters), but

most of the area is 300 to 1,200 feet (90 to 365 meters) above

sea level. In general, the area is a smooth, gently sloping plain

broken by some steep basalt ridges. The smooth plain also is

dissected into large areas by rivers and streams.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Upper Columbia (1702), 40 percent; Middle Columbia (1707),

38 percent; Yakima (1703), 17 percent; and the Lower Snake

(1706), 5 percent. The Columbia River flows through this

MLRA, and the Snake and Yakima Rivers join the Columbia

River within the MLRA. The Deschutes, John Day, and

Umatilla Rivers enter the Columbia River on the Oregon side in

this area.

Geology

This MLRA is almost entirely underlain by Miocene basalt

flows. Columbia River basalt is covered in most areas with as

much as 200 feet of eolian, lacustrine, and alluvial deposits.

This basin generally corresponds to the vast temporary lakes

created by floodwaters from glacial Lakes Missoula and

Columbia. Most of the fluvial and lacustrine sediments were

deposited about 16,000 years ago, when an ice dam on the

ancient Columbia River burst and when glacial Lake Missoula

periodically emptied, creating catastrophic floods.

Climate

The average annual precipitation is 6 to 10 inches (150 to

255 millimeters) in most of this area, but it can be as high as 20

inches (150 to 255 millimeters) in the southwest and northwest

corners. This MLRA is the warmest and driest MLRA within the

Columbia Plateau geographic area. Two-thirds of the

precipitation occurs in winter from low-intensity, Pacific frontal

storms. The winter precipitation typically occurs as a mixture of

rain and snow. Summers are dry. The average annual

temperature is 49 to 53 degrees F (9 to 12 degrees C). In most of

this area, the freeze-free period averages 160 days and ranges

from 130 to 200 days. Including the extremes at the edges of

the area, the freeze-free period averages 220 days and ranges

from 170 to 265 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 2.1%; ground water, 1.7%

Livestock—surface water, 0.1%; ground water, 0.1%

Irrigation—surface water, 80.0%; ground water, 10.8%

Other—surface water, 4.2%; ground water, 1.0%

The total withdrawals average 2,860 million gallons per day

(10,825 million liters per day). About 14 percent is from ground

water sources, and 86 percent is from surface water sources. This

area is in the rain shadow of the Cascade Mountain Range.

Irrigation is necessary for the production of agricultural crops.

The Columbia, Yakima, and Snake Rivers supply large
30 Major Land Resource Areas

quantities of surface water for irrigation. Surface water runoff is

dominated by snowmelt, and water quality is good to excellent.

Most of the irrigation water is diverted from the natural river

channels or is pumped to a higher elevation and delivered to

individual farms by gravity flow. Some high salt loads occur in

irrigation return flows. Surface water is scarce in all

nonirrigated areas.

Although ground water supplies have increased since

irrigation became established in the area, they are largely

untapped. The principal aquifer within this MLRA is Columbia

River basalt, which consists of three units in Washington called

the Grand Ronde, Wanapum, and Saddle Mountain. The Grand

Ronde aquifer occurs primarily in the west, along the Yakima

River, and in the southeast, along the Snake River. The

Wanapum and Saddle Mountain aquifers occur in most of the

rest of the MLRA. The basalt aquifer in Oregon consists of five

different groups. The basalt aquifers provide almost all of the

domestic water supply on the Columbia Plateau. The Columbia

Plateau unconsolidated aquifer occurs under a large area around

Moses Lake. This aquifer consists of glacial drift and terrace

and valley fill sediments. The aquifers in Oregon occur in areas

of river valley alluvium and basin fill. Ground water is of good

quality and has low levels of dissolved solids. It is hard or

moderately hard. Applications of fertilizer in agricultural areas

are creating high nitrate levels in some wells. Ground water

beneath the Hanford Atomic Energy Reservation has been

degraded by industrial spills and seepage.

Soils

The dominant soil orders in this MLRA are Aridisols and

Entisols. The soils in the area dominantly have a mesic soil

temperature regime, an aridic soil moisture regime, and mixed

mineralogy. They generally are moderately deep to very deep,

well drained to excessively drained, and loamy. Haplocalcids

formed in eolian deposits on hills (Adkins series) and in loess

over lacustrine deposits on stream terraces (Sagehill series).

Haplocambids formed in outwash on outwash terraces (Malaga

series) and in mixtures of loess, glaciofluvial deposits,

lacustrine deposits, alluvium, and colluvium on hills, plateaus,

benches, and terraces (Prosser, Shano, Starbuck, and Warden

series). Haplodurids formed in loess and glaciolacustrine

sediments (Burke series) and alluvium (Taunton series) on

terraces, plains, and mesas. Torriorthents formed in

glaciofluvial deposits or alluvium (Burbank and Hezel series)

or in lacustrine deposits (Kennewick series) on terraces.

Torripsamments formed in sandy eolian material on dunes

(Quincy series).

Biological Resources

This area supports shrub-grass associations. Basin big

sagebrush, Wyoming big sagebrush, and bluebunch wheatgrass

are the dominant species on the medium textured soils.

Bitterbrush and needleandthread are abundant on the sandy

soils. Very shallow soils support stiff sagebrush and Sandberg

bluegrass. Inland saltgrass, basin wildrye, and greasewood grow

on saline-alkali soils.

Some of the major wildlife species in this area are coyote,

hawks, eagles, prairie falcon, pheasant, sharp-tailed grouse,

sage grouse, gray partridge, chukar, California quail, and

burrowing owl.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 41%

Grassland—private, 28%; Federal, 14%

Urban development—private, 7%

Water—private, 5%

Other—private, 5%

About two-fifths of this area supports native grasses and

shrubs grazed by cattle. Another two-fifths is irrigated cropland

used for fruits, vegetables, sugar beets, hops, grain, hay, and

pasture. The use of sprinkler irrigation has rapidly increased in

the area. Less than one-tenth of the area is urban.

The major soil resource concerns on cropland are wind erosion,

water erosion, and maintenance of the content of organic matter

and tilth in the soils. The major concerns on rangeland are

overgrazing and invasion of undesirable plant species.

Conservation practices on cropland generally include

conservation crop rotations, crop residue management, waste

utilization, nutrient management, pest management, filter strips,

and irrigation water management. These practices help to

control erosion and protect water quality.

Conservation practices on rangeland generally include brush

management, prescribed grazing, prescribed burning, exclusion

from use as needed, and range planting. Rangeland

conservation systems help to control erosion, improve forage

production, and protect water quality.

Conservation practices on pasture and hayland generally

include prescribed grazing, forage harvest management,

nutrient management, waste utilization, and filter strips. These

practices protect water quality and aquatic habitat for fish and

wildlife by reducing the movement of nutrients and pesticides

to surface water and ground water. 
of the United States 31

Figure 8-1: Location of MLRA 8 in Land Resource Region B.

8—Columbia Plateau

 This area (shown in fig. 8-1) is primarily in Washington (75

percent) and Oregon (25 percent), but it includes a small area in

Idaho. It makes up about 18,505 square miles (47,955 square

kilometers). The towns of Pendleton, Oregon, and Walla Walla

and Ellensburg, Washington, are in this MLRA. Interstate 90

bisects the northern half of the MLRA, and Interstate 84 follows

the south side of the Columbia River until it turns east to

Pendleton. Interstate 82 connects Interstates 90 and 84,

following the Yakima River for most of its length. Grand

Coulee Dam on the Columbia River and many State wildlife

refuges occur in the area. Parts of the Yakama and Colville

Indian Reservations also occur in the area.

Physiography

Almost all of this area lies within the Walla Walla Plateau

Section of the Columbia Plateaus Province of the Intermontane

Plateaus. The plateau is nearly level to steeply sloping, and its

surface is a series of rolling hills with young, incised valleys.

Some areas of the western and far northwestern parts of this

MLRA lie within the Northern and Middle Cascade Mountains of

the Cascade-Sierra Mountains Province of the Pacific Mountain

System. Some areas of the far northern and northeastern parts of

the MLRA are within the Northern Rocky Mountains Province of

the Rocky Mountain System. The valley of the south-flowing

Okanogan River separates the Pacific Mountain and Rocky

Mountain Systems near the Canadian border.

Elevation in this area is 1,300 to 3,600 feet (395 to 1,100

meters). The area is characterized by a nearly level basalt

plateau. The higher elevations occur along the western and

northernmost edges of the area. Steep slopes are common along

the walls of the major valleys and in scablands.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Upper Columbia (1702), 45 percent; Middle Columbia (1707),

32 percent; Yakima (1703), 12 percent; and Lower Snake

(1706), 11 percent. The south- and west-flowing Columbia

River bisects this area. Two major tributaries of the Columbia,

the Yakima and Snake Rivers, cross the middle portions of this

MLRA. The Deschutes and John Day Rivers enter the

Columbia River from the Oregon side.

Geology

This MLRA is almost entirely underlain by Miocene basalt

flows. Columbia River basalt is covered in many areas with as

much as 200 feet of loess and volcanic ash. Small areas of

sandstones, siltstones, and conglomerates of the Upper Tertiary

Ellensburg Formation are along the western edge of this area.

Some Quaternary glacial drift covers the northern edge of the

basalt flows, and some Miocene-Pliocene continental

sedimentary deposits occur south of the Columbia River, in

Oregon. The sediments in Oregon were deposited during

episodes of natural damming of the Columbia River. These

river-laid deposits have layers of ash-flow tuffs and some

interbedded rhyolite flows. A wide expanse of scablands in the

eastern portion of this MLRA, in Washington, was deeply

dissected about 16,000 years ago, when an ice dam that formed

ancient glacial Lake Missoula was breached several times,

creating catastrophic floods.

 The geology of the northernmost part of this MLRA is

distinctly different from that of the rest of the area. Alluvium,

glacial outwash, and glacial drift fill the valley floor of the

Okanogan River and the side valleys of tributary streams. The

fault parallel with the valley separates pre-Tertiary metamorphic

rocks on the west, in the Cascades, from older, pre-Cretaceous

metamorphic rocks on the east, in the Northern Rocky

Mountains. Mesozoic and Paleozoic sedimentary rocks cover

the metamorphic rocks for most of the length of the valley on

the west.

Climate

The average annual precipitation is 10 to 16 inches (255 to

405 millimeters) in most of this area. It can be as low as 6

inches (150 millimeters) along the boundary with the drier

Columbia Basin and as high as 36 inches (915 millimeters) in

the foothills in the valley of the Okanogan River. More than 80

percent of the precipitation occurs in fall, winter, and spring

from low-intensity, Pacific frontal storms. The precipitation

typically occurs as rain in fall and spring but may occur as

either rain or snow in winter. The average annual temperature is

48 to 54 degrees F (8 to 12 degrees C) in most of the area. It can
32 Major Land Resource Areas

be as low as 41 degrees F (5 degrees C) in the valley of the

Okanogan River. In most areas the freeze-free period averages

190 days and ranges from 130 to 245 days. The longest freezefree periods are along the border between this area and the

Columbia Basin and in the river gorges. The freeze-free period

can be as short as 100 days in the higher parts of the valley of

the Okanogan River.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 3.5%; ground water, 1.9%

Livestock—surface water, 0.1%; ground water, 0.1%

Irrigation—surface water, 77.3%; ground water, 8.8%

Other—surface water, 7.1%; ground water, 1.1%

The total withdrawals average 4,925 million gallons per day

(18,640 million liters per day). About 12 percent is from ground

water sources, and 88 percent is from surface water sources. This

area is in the rain shadow of the Cascade Mountain Range. The

low or moderate precipitation limits the choice of agricultural

enterprises. The major rivers provide water for irrigation along

their courses, but small streams provide little water. Surface

water runoff is dominated by snowmelt, and water quality is

good to excellent. Some high salt loads occur in irrigation

return flows.

 The principal aquifer in the northernmost part of this MLRA

is the Northeast glacial drift aquifer underlying the valley of the

Okanogan River. Some ground water is derived from small areas

of glacial drift and terrace-and-valley or basin fill aquifers

along the western edges of the MLRA and south of the

Columbia River, in Oregon. In the rest of the MLRA, the

supplies of ground water in the underlying basalt are small and

mostly untapped. The Columbia River basalt aquifer consists of

three units in Washington called the Grand Ronde, Wanapum,

and Saddle Mountain. The Grand Ronde occurs in the west, the

Wanapum dominates the east, and the Saddle Mountain lies

between the other two. The basalt is not differentiated in

Oregon. Ground water is of good quality and has low levels of

dissolved solids. The basalt aquifers provide almost all of the

domestic water supply on the Columbia Plateau. The water is

hard or moderately hard. Applications of fertilizer in

agricultural areas are creating high nitrate levels in some wells.

Soils

The dominant soil order in this MLRA is Mollisols. The

soils in the area dominantly have a mesic soil temperature

regime, a xeric soil moisture regime, and mixed mineralogy.

They generally are moderately deep to very deep, well drained,

and loamy. Haploxerolls formed in loess (Anders, Condon,

Mikkalo, Ritzville, and Walla Walla series), loess mixed with

glaciofluvial sediments (Roloff series), ash over loess (Valby

series), loess over outwash (Benge series), mixed materials (very

shallow Bakeoven and shallow Kuhl series), and colluvium

(shallow Lickskillet series) on uplands. Argixerolls (Bagdad,

Morrow, and Renslow series) formed in loess on plateaus and

hills. Durixerolls (Willis series) formed in ash over loess on

terraces and uplands. Haploxerolls (Esquatzel, Hermiston, and

Onyx series) formed in alluvium on flood plains.

Biological Resources

This area supports shrub-grass associations. Basin big

sagebrush, Wyoming big sagebrush, and bluebunch wheatgrass

are dominant on the moderately deep to very deep, gently

sloping and moderately sloping soils and on soils that have

steep and very steep south exposures. Basin big sagebrush and

Idaho fescue are dominant on most moist sites and on

moderately steep to very steep north exposures. Stiff sagebrush,

low sagebrush, and Sandberg bluegrass are dominant on

shallow and very shallow, stony soils. Small stands of

ponderosa pine, along with oak on the warmer sites along the

Columbia River, are on north-facing slopes, in canyons and

draws, and along stream channels. Dwarf hardwoods of

hackberry and maple also grow in canyons and draws.

Snowberry is the most common shrub in the pine stands.

Poison-oak is the most common shrub in the oak stands.

 Some of the major wildlife species in this area are mule

deer, coyote, bobcat, goshawk, Cooper’s hawk, sharp-tailed

grouse, pheasant, Canada goose, cackling goose, English

sparrow, and dusky horned lark. The species of fish in the area

include steelhead trout, rainbow trout, brown trout, Chinook

salmon, bullhead, channel catfish, and sturgeon.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 43%

Grassland—private, 42%; Federal, 6%

Forest—private, 3%

Urban development—private, 2%

Water—private, 1%

Other—private, 3%

More than two-fifths of this area is cropland, which is mostly

dry-farmed. Where the annual precipitation exceeds 14 inches

(355 millimeters), the main crops are wheat, barley, peas, and

lentils, but a small acreage is used for alfalfa, grass, or improved

pasture. Where the annual precipitation is less than about 14

inches (355 millimeters), a cropping system of alternate grain

and summer fallow is used. Small areas along the major streams

are used for irrigated vegetables, apples, or hay. Less than onehalf of the area is used as rangeland. A few small areas are used

as woodland.

 The major soil resource concerns on cropland are wind

erosion, water erosion, sedimentation of streams and road
of the United States 33

ditches, and maintenance of the content of organic matter and

tilth in the soils. The major concerns on rangeland are

overgrazing and invasion of undesirable plant species.

Conservation practices on cropland generally include

conservation crop rotations, crop residue management, terraces,

waste utilization, nutrient management, pest management, filter

strips, grassed waterways, and irrigation water management.

These practices help to control erosion and protect water

quality. Conservation practices on rangeland generally include

brush management, prescribed grazing, prescribed burning,

exclusion from use as needed, and range planting.

Conservation practices on pasture and hayland generally

include prescribed grazing, forage harvest management,

nutrient management, waste utilization, and filter strips. These

practices protect water quality and aquatic habitat for fish and

wildlife by reducing the movement of nutrients and pesticides

to surface water and ground water.

Conservation practices on forestland generally include

forest site preparation, forest stand improvement, and forest

trails and landings. These practices help to control surface

compaction, the erosion caused by concentrated flow, and

sediment delivery to streams. 

Figure 9-1: Location of MLRA 9 in Land Resource Region B.

9—Palouse and Nez Perce Prairies

This area (shown in fig. 9-1) is in Washington (52 percent),

Oregon (28 percent), and Idaho (20 percent). It makes up about

8,810 square miles (22,825 square kilometers). The towns of

Moscow, Idaho, and Pullman, Washington, are in this MLRA.

Spokane, Washington, is just outside the northern border of the

MLRA. Interstate 90 crosses the northern half of the MLRA,

and Interstate 84 crosses the southernmost parts. Very small

portions of the Wallowa-Whitman and Umatilla National

Forests occur in this MLRA. The Turnbull and Chief Joseph

State Wildlife Refuges and the Umatilla, Coeur d’Alene, and

Nez Perce Indian Reservations also are in this MLRA.

Physiography

Almost all of this MLRA lies within the Walla Walla Plateau

Section of the Columbia Plateaus Province of the Intermontane

Plateaus. The area is characterized by an undulating basalt

plaeau that has been highly dissected. The major streams have

cut deep, steep-walled canyons. The plateau is nearly level to

steeply sloping, and its surface is moderately dissected or

strongly dissected. Slopes are mostly hilly and steep. Some

areas in the southeastern portion of this MLRA are in the Blue

Mountain Section of the Columbia Plateaus Province. Small

areas on the eastern edge of the area are in the Northern Rocky

Mountains Province of the Rocky Mountain System. Elevation

along the major streams is about 650 feet (200 meters). On most

of the plain, however, it ranges from 2,000 to 4,000 feet (610 to

1,220 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Lower Snake (1706), 72 percent; Middle Columbia (1707), 12

percent; Kootenai-Pend Oreille-Spokane (1701), 11 percent;

Upper Columbia (1702), 2 percent; and Middle Snake (1705), 1

percent. The Snake River flows in the center of this MLRA,

where it forms the border between Washington and Idaho and

between Oregon and Idaho. The Spokane River forms part of

the northern boundary of the MLRA.

Geology

This MLRA is almost entirely underlain by Miocene basalt

flows. Columbia River basalt is covered in many areas by thick

layers of loess and volcanic ash. Some Mesozoic sedimentary

rocks occur along the eastern edge of the southeast limb of this

MLRA, and some Precambrian sediments are exposed in a

portion of the MLRA in the southeast corner of Washington.

Climate

The average annual precipitation is 13 to 28 inches (330 to

710 millimeters) in most of this area. It can be as low as 9

inches (230 millimeters) along parts of the western border and

as high as 43 inches (1,090 millimeters) on the southern border,

where the area butts against MLRAs that are much higher in

elevation. Winter precipitation, primarily snow, occurs during

low-intensity, Pacific frontal storms. During winter, these storms

produce occasional rains that fall on frozen or thawing ground
34 Major Land Resource Areas

surfaces. High-intensity, convective thunderstorms produce

some rain during the growing season. Precipitation is evenly

distributed throughout fall, winter, and spring. Summers are

relatively dry. The average annual temperature is 47 to 54

degrees F (8 to 12 degrees C) in most of this area, but it can be

as low as 40 degrees F (5 degrees C) at the higher elevations in

the south. Including the extremes at the edges of this MLRA,

the freeze-free period averages 165 days and ranges from 100 to

230 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 10.7%; ground water, 7.4%

Livestock—surface water, 0.3%; ground water, 2.4%

Irrigation—surface water, 47.2%; ground water, 6.4%

Other—surface water, 20.6%; ground water, 4.9%

The total withdrawals average 625 million gallons per day

(2,365 million liters per day). About 21 percent is from ground

water sources, and 79 percent is from surface water sources.

Precipitation is adequate for dryland farming. The Snake River

and many of the smaller rivers and streams provide water for

irrigation and hydroelectric power generation. Surface water

runoff is dominated by snowmelt, and water quality is good to

excellent. Some high sediment and salt loads occur during high

runoff periods and in irrigation return flows. Runoff from mine

tailings and from municipal and industrial waste causes

problems with surface water quality in some areas.

The principal aquifer in this MLRA is Columbia River

basalt. The basalt has layers of tuffaceous sediments that also

yield ground water. Some ground water is derived from small

areas of glacial drift and terrace-and-valley or basin fill

deposits. The Columbia River basalt aquifer consists of three

units in Washington called the Grand Ronde, Wanapum, and

Saddle Mountain, all of which occur in this MLRA. The basalt

is not differentiated in Idaho or Oregon. The ground water is of

good quality and has low levels of dissolved solids. It is hard or

moderately hard.

Soils

The dominant soil order in this MLRA is Mollisols. The

soils in the area dominantly have a mesic or frigid soil

temperature regime, a xeric soil moisture regime, and mixed

mineralogy. They are generally deep or very deep, well drained

or moderately well drained, and loamy. Haploxerolls formed in

loess (Palouse and Athena series) on hills and in glaciofluvial

deposits with an ash and loess mantle (Cheney series) and

colluvium mixed with loess and ash (shallow Rockly series) on

uplands. Argixerolls formed in loess (Larkin, Naff, Southwick,

and Thatuna series) on hills and plateaus, in ash-mantled loess

(Taney series) on plains and plateaus, in loess-mantled outwash

(Hesseltine series), and in loess-mantled colluvium and

residuum (Gwin and Waha series).

Biological Resources

This area supports grass, shrubs, and trees. The rangeland

areas support a shrub-grassland plant community in which the

dominant shrub is snowberry in the eastern part of the MLRA

and big sagebrush in the western part. Bluebunch wheatgrass

and Idaho fescue are the dominant grasses. Rose, common

cowparsnip, black hawthorn, and arrowleaf balsamroot also

are important. On forestland, ponderosa pine and Douglas-fir

are the major tree species and the understory is mainly

snowberry, ninebark, Idaho fescue, bluebunch wheatgrass, and

pinegrass.

Some of the major wildlife species in this area are deer,

pheasant, chukar, Hungarian partridge, California quail,

mourning dove, thrushes, vireos, and woodpeckers.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 58%

Grassland—private, 29%; Federal, 1%

Forest—private, 7%

Urban development—private, 3%

Water—private, 1%

Other—private, 1%

Some small areas of forestland are on north-facing slopes.

The rangeland in the area is on breaks, scablands, and buttes.

Dry-farmed wheat is the major crop in the areas of cropland.

Both annual cropping and fallow systems are common. Other

important crops are barley, peas, lentils, alfalfa, and grasses. A

small part of the cropland is irrigated and used for vegetables

and other specialty crops. A few small areas are developed for

urban uses.

The major soil resource concerns are water erosion and

maintenance of the content of organic matter and tilth in the

soils. Water erosion caused by snowmelt or rainfall when the

soils are frozen or thawing is of particular concern. The major

concerns on rangeland are overgrazing and invasion of

undesirable plant species.

Conservation practices on cropland generally include

conservation crop rotations; crop residue management systems,

such as mulch-till and no-till; terraces; contour stripcropping;

cross-slope farming; divided slopes; buffer strips; water- and

sediment-control basins; grassed waterways; nutrient

management; pest management; and irrigation water

management. These practices help to control erosion and

protect water quality. Conservation practices on rangeland

generally include brush management, prescribed grazing,

prescribed burning, exclusion from use as needed, and range

planting.
of the United States 35

Conservation practices on pasture and hayland generally

include prescribed grazing, forage harvest management,

nutrient management, waste utilization, and filter strips. These

practices protect water quality and aquatic habitat for fish and

wildlife by reducing the movement of nutrients and pesticides

to surface water and ground water.

Conservation practices on forestland generally include

forest site preparation, forest stand improvement, and forest

trails and landings. These practices help to control surface

compaction, the erosion caused by concentrated flow, and

sediment delivery to streams. 

Figure 10-1: Location of MLRA 10 in Land Resource Region B.

10—Central Rocky and Blue Mountain

Foothills

This area (shown in fig. 10-1) is in Oregon (71 percent) and

Idaho (29 percent). It makes up about 17,515 square miles

(45,385 square kilometers). Bend, Oregon, is near the western

edge of the MLRA, and Boise, Idaho, is near the southern edge.

Also included are John Day and Baker City, Oregon. Interstate

84 crosses the part of the area in western Oregon. Small parts of

many national forests are on the edges of the area. Craters of the

Moon National Monument is in the far eastern end of the area,

and the John Day Fossil Beds National Monument is in the

western part.

Physiography

Almost all of this MLRA is in the Columbia Plateaus

Province of the Intermontane Plateaus. The western half of this

area is in the Walla Walla Plateau Section, which is an area of

rolling plateaus with young, incised valleys. A portion on the

west edge of Idaho is in the Payette Section, which also is a

young area of dissected plateaus. The eastern one-quarter of the

MLRA is in two different physiographic provinces. The north

half is in the Northern Rocky Mountains Province of the Rocky

Mountain System, and the south half is in the Snake River

Plain Section of the Intermontane Plateaus. A small area

connecting the Oregon and Idaho parts of the MLRA is in the

Harney Section of the Intermontane Plateaus. It is a young lava

plateau with some evidence of recent volcanism. Small areas of

the central portion of the MLRA are in the Blue Mountain

Section, which is a dissected volcanic plateau in a complex of

mountains. This MLRA is typified by gently rolling to steep

hills, plateaus, and low mountains. Elevation ranges from 1,300

to 6,600 feet (395 to 2,010 meters), increasing from west to east.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Middle Snake (1705), 47 percent; Middle Columbia (1707), 36

percent; Upper Snake (1704), 14 percent; and Oregon Closed

Basins (1712), 3 percent. The Deschutes and John Day Rivers,

below the Blue Mountains in Oregon, are in this MLRA. The

Snake River cuts across the area at the border between Oregon

and Idaho.

Geology

The geology of this MLRA varies widely in age and

lithology. It ranges from raw young lava flows at Craters of the

Moon National Monument, Idaho, to very old Cretaceous rocks

at John Day Fossil Beds National Monument, Oregon. The part

of the area in southwest and south-central Idaho consists of

basalt flows from the Columbia and Idaho Batholiths. The

flows in the east half are cut by Yellowstone Volcanics. Some

Paleozoic sediments occur in the east. Deep alluvial deposits

are in valleys along the major streams and on fans adjacent to

the mountains. Lithologies include basalt, rhyolite, schist,

granite, graywacke, limestone, sandstone, and tuff.

Climate

The average annual precipitation is 8 to 16 inches (205 to

405 millimeters) in most of this area. It increases from west to

east and with elevation. It is as much as 41 inches (1,040

millimeters) at the higher elevations along the northern

border of the area. Precipitation is evenly distributed

throughout fall, winter, and spring but is low in summer.

Some high-intensity, convective thunderstorms occur during
36 Major Land Resource Areas

the growing season. Winter precipitation is primarily snow. The

average annual temperature is 36 to 53 degrees F (2 to 12

degrees C). The freeze-free period averages 140 days and ranges

from 60 to 220 days, decreasing from west to east and with

elevation.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 1.7%; ground water, 0.9%

Livestock—surface water, 0.1%; ground water, 1.9%

Irrigation—surface water, 67.3%; ground water, 21.7%

Other—surface water, 5.1%; ground water, 1.4%

The total withdrawals average 4,100 million gallons per day

(15,520 million liters per day). About 26 percent is from ground

water sources, and 74 percent is from surface water sources.

Streams provide enough irrigation water to meet the present

needs along the major valleys. Runoff from snowmelt is the

principal source of surface water, and water quality is good to

excellent. The surface water is typically soft.

The principal aquifers in this MLRA are Columbia River

basalt and basin fill and alluvial aquifers in Oregon and the

basalt aquifer and sedimentary and volcanic aquifer in Idaho.

The chemical quality of the ground water is good to excellent,

meeting national drinking water standards. The water is hard or

moderately hard. In Idaho, the ground water can be thermal,

170 to 200 degrees F (76 to 95 degrees C), or nonthermal, 78

degrees F (25.5 degrees C). Thermal water sources generally are

more than 400 feet from the land surface. Nonthermal water

wells typically are less than 400 feet deep.

Soils

The dominant soil order in this MLRA is Mollisols.

Aridisols are of minor extent. The soils in the area have a mesic

or frigid soil temperature regime, a xeric or aridic soil moisture

regime, and mixed or smectitic mineralogy. They are very

shallow to very deep, well drained, and clayey or loamy.

Haploxerolls formed in residuum (Bakeoven series) and

colluvium (Lickskillet, Rockly, and Westbutte series) on hills,

plateaus, and mountains. Palexerolls (Simas series) formed in

mixed loess and colluvium on hills. Argixerolls formed in ash

(Tub series), in eolian sediments (Madras series), in residuum

(Deshler, Gem, Merlin, Reywat, and Waterbury series), and in

residuum mixed with alluvium, colluvium, or loess (Ateron,

McCarey, Riggins, Ruckles, and Vitale series) on hills, plateaus,

and mountains. Argixerolls also formed in mixed alluvium and

colluvium on fan terraces, hills, and mountains (Simonton

series).

Biological Resources

This area supports a shrub-grass association. Big sagebrush,

bluebunch wheatgrass, and Idaho fescue are the dominant

species. Stiff sagebrush, low sagebrush, and Sandberg bluegrass

are dominant on the drier sites. Antelope bitterbrush grows on

moist sites. Western juniper is associated with rock outcrop and

rubbly areas. With the suppression of wildfires, western juniper

has greatly expanded its extent in Oregon.

Some of the major wildlife species in this area are antelope,

mule deer, coyote, porcupine, beaver, golden eagle, Cooper’s

hawk, and chukar. The species of fish in the area include trout

in the perennial streams and rivers; steelhead trout and salmon

in the Deschutes and John Day Rivers in Oregon; and warmwater fish, such as bluegill, crappie, perch, catfish, and bass, in

ponds and reservoirs.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 8%

Grassland—private, 43%; Federal, 42%

Forest—private, 1%; Federal, 3%

Urban development—private, 1%

Water—private, 1%

Other—private, 1%

Nearly half of the MLRA is federally owned and managed

by the Bureau of Land Management. The rest is mainly in farms

or ranches. Most of the area is used for livestock grazing.

Irrigated agriculture occurs along the major rivers and in the

Deschutes Basin in Oregon. Both irrigated and nonirrigated

agriculture occur on the Camas Prairie in Idaho. Alfalfa and

small grains are the dominant crops. Specialty crops, such as

mint, carrots, onions, and fruits, can be grown in local areas.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and

productivity of the soils, loss of nutrients, streambank erosion,

mass movement of soil caused by overuse of irrigation water,

conservation of soil moisture, and preservation of water quality.

Conservation practices on cropland generally include

irrigation water management, water-control structures, irrigation

system improvements, nutrient management, critical area

plantings, and streambank stabilization.

Conservation practices on rangeland and pasture generally

include prescribed grazing, spring development, watering

facilities, wells, pipelines, fencing, and brush management.

Cool-season grasses, both introduced and native, are often

planted to improve production and forage quality. Renovation

of old pastures may include chiseling, disking, and applying

fertilizer. 
of the United States 37

Figure 11-1: Location of MLRA 11 in Land Resource Region B.

11—Snake River Plains

This area (shown in fig. 11-1) is in Idaho (94 percent) and

Oregon (6 percent). It makes up about 16,475 square miles

(42,685 square kilometers). Most of the area is on the Snake

River Plain in Idaho. A small area is west of the Snake River in

Oregon. Boise, Twin Falls, and Idaho Falls, Idaho, and Ontario,

Oregon, are in this MLRA. Interstate 84 follows the Snake

River through the west half of the area, Interstate 15 cuts across

the easternmost part, and Interstate 86 connects Interstates 84

and 15 in Pocatello, Idaho, on the southern boundary of the

MLRA. Part of the Fort Hall Indian Reservation, the Deer Flat

National Wildlife Refuge, the Snake River Birds of Prey

Wilderness Study Area, and the Idaho National Engineering and

Environmental Laboratory are in this MLRA.

Physiography

All of this MLRA is in the Columbia Plateaus Province of

the Intermontane Plateaus. The west half is in the Payette

Section, and the east half is in the Snake River Plain Section.

These two sections are essentially young, nearly level to gently

sloping lava plateaus. Elevation ranges from 2,100 to 5,000

feet (640 to 1,525 meters). Some of the major streams have cut

deep, steep-walled canyons in the basalt flows and terraces.

Alluvial fans, terraces, and bottom lands are gently sloping or

moderately sloping.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Upper Snake (1704), 63 percent, and Middle Snake (1705), 37

percent. The Snake River, which has broad alluvial terraces

paralleling it, runs through the center of the MLRA.

Geology

This area consists of lava plains formed from the Idaho

Batholith and from Columbia River basalt flows. Floods from a

breach of glacial Lake Bonneville formed the valley of the

Snake River Plain. The present-day Snake River cut through

the glacial outwash, lacustrine deposits, and river alluvium and

into the lava plain on the valley floor, leaving broad terraces

along the river. Loess covers most of this MLRA. Alluvial fans

encroach on the edges of the plains, where they are bordered by

mountains.

Climate

The average annual precipitation is 7 to 12 inches (180 to

305 millimeters) in most of this area. It can be as high as 20

inches (510 millimeters) at the higher elevations in the

northeast corner. Spring rains are important to agriculture on

the Snake River Plain. Most of the precipitation falls as rain in

fall, winter, and spring. Snowfall is common during winter.

Little or no precipitation occurs in summer. The average annual

temperature is 41 to 55 degrees F (5 to 13 degrees C). The

freeze-free period averages 165 days and ranges from 110 to

220 days. It is shortest in the northeastern part of the area.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.2%; ground water, 1.0%

Livestock—surface water, 0.0%; ground water, 2.8%

Irrigation—surface water, 61.6%; ground water, 32.8%

Other—surface water, 0.4%; ground water, 1.0%

The total withdrawals average 13,240 million gallons per day

(50,115 million liters per day). This is the second highest

amount of water used among all of the MLRAs. About 38

percent is from ground water sources, and 62 percent is from

surface water sources. Large quantities of surface water are

available for irrigation along the Snake River and its

tributaries. The surface water is derived primarily from

snowmelt runoff. It is soft water of good to excellent quality.

Ground water is plentiful in some of the deep alluvial

deposits throughout the area, in the lava north of the Snake

River in eastern and south-central Idaho, and in the Columbia

River basalt in Oregon. The ground water comes from the

sedimentary and volcanic aquifers under the Snake River Plain

in the western half of the area. The water is hard or moderately

hard and is of good to excellent quality. It is used extensively

for irrigation. In Idaho, the ground water can be thermal, 170 to

200 degrees F (76 to 95 degrees C), or nonthermal, 78 degrees
38 Major Land Resource Areas

12—Lost River Valleys and Mountains

This area is entirely in Idaho (fig. 12-1). It makes up about

6,070 square miles (15, 735 square kilometers). It has no major

cities. The major centers of commerce are Challis and Salmon.

Interstate 15 crosses the far eastern end of the area. Several

national forests are in this MLRA, including the Salmon,

Targhee, and Challis National Forests.

Physiography

This area is almost entirely within the Northern Rocky

Mountains Province of the Rocky Mountain System. It consists

of deeply dissected mountain uplands and intermontane basins

aligned along a northwest to southeast axis. The mountains are

not anticlinal ranges. Elevation ranges from 4,000 feet (1,220

meters) in the valleys to more than 12,000 feet (3,660 meters) at

the highest mountain crests. Steep or very steep mountains

make up about 50 percent of the area. The expansive valleys

are level to moderately steep. Broad coalesced alluvial fans

extend from the foot of the mountains to the stream terraces in

the center of the valleys. The southern end of the area extends

out onto a high part of the Snake River Plain Section of the

Columbia Plateaus Province of the Intermontane Plateaus. This

young lava plateau is level to steep. Alpine glaciation was

quite extensive in the mountains of this MLRA.

F (25.5 degrees C). Thermal water sources generally are more

than 400 feet from the land surface. Nonthermal water wells

typically are less than 400 feet deep.

Soils

The dominant soil order in this MLRA is Aridisols. The soils

in the area dominantly have a mesic or frigid soil temperature

regime, an aridic soil moisture regime, and mixed or smectitic

mineralogy. They are shallow to very deep and generally are

well drained. They are silty, loamy, or clayey and commonly are

skeletal. Haplocalcids formed in loess (Pancheri series), in

mixed alluvium and lacustrine deposits (Declo series), and in

mixed loess and alluvium (Portneuf and Bahem series) on fan

terraces, hills, and plains. Calciargids (Power and Paulville

series) formed in mixed loess and ash over alluvium on plains

and in valleys. Argidurids formed in mixed loess and ash over

alluvium (Chilcott, Elijah, and Purdam series) and in mixed

alluvium and ash (Colthorp series) on plains and terraces and in

valleys. Haplocambids formed in loess and alluvium over

basalt (Trevino series) on plains.

Biological Resources

This area supports an overstory of sagebrush and an

understory of grasses. Big sagebrush, winterfat, shadscale,

Indian ricegrass, needleandthread, Thurber needlegrass,

and Sandberg bluegrass grow on the lower Snake River

Plains. Big and threetip sagebrush, bluebunch wheatgrass,

Thurber needlegrass, and arrowleaf balsamroot grow on the

middle Snake River Plains. Bluebunch wheatgrass and big

sagebrush grow on the upper Snake River Plains. Black

sagebrush and Gardner’s saltbush are dominant on some soils.

Phlox, tapertip hawksbeard, biscuitroot, and penstemon also

are important.

Some of the major wildlife species in this area are mule

deer, antelope, bald eagle, golden eagle, and pheasant. The

species of fish in the area include rainbow trout, walleye, brown

trout, kokanee, smallmouth bass, perch, black crappie, and

sturgeon.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 28%

Grassland—private, 18%; Federal, 47%

Urban development—private, 4%

Water—private, 1%

Other—private, 2%

Rangeland and irrigated cropland are the major uses in this

area. Forage production is low, and annual grasses have invaded

much of the rangeland in the western part of the area as a result

of repeated wildfires. About one-fourth of the area (the plains

bordering the Snake River and its tributaries) is irrigated.

Potatoes, grain, sugar beets, beans, and alfalfa hay are the

principal crops. The area has a wide variety of specialty crops,

such as hops, vegetables, vegetable seeds, mint, and onions,

especially in the Treasure Valley west of Boise. Some areas are

used as irrigated pasture.

The major soil resource concerns on cropland are wind

erosion, water erosion, and maintenance of the content of

organic matter and tilth in the soils. The major concerns on

rangeland are overgrazing and invasion of undesirable plants.

Conservation practices on cropland generally include

conservation crop rotations, crop residue management, waste

utilization, nutrient management, pest management, filter strips,

and irrigation water management. These practices help to

control erosion and protect water quality. Conservation

practices on rangeland generally include brush management,

prescribed grazing, prescribed burning, exclusion from use as

needed, and range planting.

Conservation practices on pasture and hayland generally

include prescribed grazing, forage harvest management,

nutrient management, waste utilization, and filter strips. These

practices protect water quality and aquatic habitat for fish and

wildlife by reducing the movement of nutrients and pesticides

to surface water and ground water. 
of the United States 39

convective thunderstorms occur during summer. The average

annual temperature is 35 to 45 degrees F (2 to 7 degrees C) in

the valleys but is much lower in the mountains. The freeze-free

period averages 110 days and ranges from 65 to 150 days in

most of this area. At the higher elevations, however, freezing

may occur during every month of the year.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.1%; ground water, 0.3%

Livestock—surface water, 0.0%; ground water, 1.0%

Irrigation—surface water, 62.5%; ground water, 35.8%

Other—surface water, 0.0%; ground water, 0.4%

The total withdrawals average 1,050 million gallons per day

(3,975 million liters per day). About 37 percent is from ground

water sources, and 63 percent is from surface water sources.

Both the surface water and the ground water are available in

limited supply. The Big Lost and Little Lost Rivers are two of

many streams north of the Snake River Plain that do not reach

the Snake River. Streamflow infiltrates to the basalt aquifer

under the Snake River Plain. The only other sources of ground

water in this area are valley fill aquifers.

The moderate precipitation provides enough moisture for

grass and shrubs to grow on mountain slopes. The valleys

depend on the streamflow of the Salmon, Lemhi, Pahsimeroi,

Big Lost, and Little Lost Rivers for livestock and irrigation

water. The surface water is derived from snowmelt runoff and is

of exceptionally good quality. Springs and deep wells in the

valleys supply ground water for domestic uses and for

irrigation. The ground water is of good to excellent quality and

is typically nonthermal, less than 78 degrees F (25.5 degrees C).

Soils

The dominant soil orders in this MLRA are Mollisols and

Aridisols. Histosols occur in old oxbows on flood plains. The

soils in the area dominantly have a frigid or cryic soil

temperature regime, a xeric or aridic soil moisture regime, and

mixed, carbonatic, or siliceous mineralogy. They generally are

very deep, well drained, and loamy, loamy-skeletal, or sandyskeletal. Argixerolls (Cronks and Dacont series), Argicryolls

(Zeebar series), and Calciargids (Dawtonia series) formed in

colluvium on foothills and mountains. Haplocalcids (Simeroi

and Whiteknob series) and Haplocambids (Pahsimeroi series)

formed in alluvium on outwash fans and alluvial fans.

Haplocalcids (Zer series) also formed in loess and colluvium on

mountains and foothills. Natrargids (Millhi series) formed in

lacustrine sediments on foothills and lake terraces. Cryosaprists

(Grandjean series) formed in organic material in old oxbows on

flood plains at high elevations.

Figure 12-1: Location of MLRA 12 in Land Resource Region B.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Upper Snake (1704), 55 percent, and Lower Snake (1706), 45

percent. The Lemhi and Pahsimeroi Rivers are major tributaries

to the Salmon River. The Big Lost and Little Lost Rivers flow

into alluvial sinks in the southeast portion of the MLRA. The

East Fork of the Salmon River is in this area. The Salmon River

is a major tributary of the Snake River, joining the Snake near

the Idaho, Oregon, and Washington borders.

Geology

Mixed sedimentary and metasedimentary rocks and volcanic

rocks underlie the mountains. The Idaho Batholith and Challis

Volcanics dominate the north half of the area, and Paleozoic

sediments are more common in the south half. The valleys and

the portion of this area on the Snake River Plain are deeply

mantled by recent alluvium and some lacustrine deposits. The

rivers are incised with terraces in the valleys, and high alluvial

fans occur on the valley floors and Snake River Plain next to the

mountains.

Climate

The average annual precipitation is 7 to 25 inches (180 to

635 millimeters) in the valleys and 45 inches (1,145

millimeters) or more on mountain crests. Most of the

precipitation occurs as rain and snow in fall, winter, and spring.

It is dominantly snow in winter. A few high-intensity,
40 Major Land Resource Areas

13—Eastern Idaho Plateaus

This area (shown in fig. 13-1) is primarily in Idaho (99

percent), but it includes a small part of Utah (1 percent). It

makes up about 7,270 square miles (18,840 square kilometers).

It has no major cities. Rexburg, Idaho Falls, and Pocatello,

Idaho, are directly west of the MLRA boundary. Interstate 15

cuts this area in half north to south and intersects with Interstate

86 in Pocatello just outside of the MLRA. The Fort Hall Indian

Reservation and several national forests are in this MLRA,

including the Caribou, Cache, and Targhee National Forests.

Yellowstone and Grand Teton National Parks occur just outside

the northeast boundary.

Physiography

Most of this area is in the Great Basin Section of the Basin

and Range Province of the Intermontane Plateaus. This is an

area of isolated, fault-block mountain ranges that are dissected.

The mountain ranges are aligned almost north to south and are

separated by aggraded desert plains. This MLRA is very narrow

where the Snake River crosses it. The portion north of the

Snake River, about 20 percent of the area, is in the Snake River

Plain Section of the Columbia Plateaus Province of the

Intermontane Plateaus. The plain is a young lava plateau. The

southeast corner and the easternmost valleys of the Snake and

Teton Rivers in the area are in the Middle Rocky Mountains

Province of the Rocky Mountain System. Elevation ranges

from 4,500 to 6,600 feet (1,370 to 2,010 meters) on the plateaus

Biological Resources

This area supports desert shrub, shrub-grass, and forest

vegetation. Indian ricegrass, needleandthread, shadscale,

Gardner’s saltbush, and scarlet globemallow are the major

species in the valleys. Wyoming big sagebrush, black

sagebrush, low sagebrush, winterfat, bluebunch wheatgrass,

Sandberg bluegrass, and a variety of forbs grow on mountain

footslopes. Bluebunch wheatgrass, prairie junegrass,

oniongrass, Indian paintbrush, lupine, sedge, big and low

sagebrush, and rabbitbrush grow on low mountain slopes. Curlleaf mountain mahogany, Douglas-fir, aspen, and Rocky

Mountain juniper grow on mountain slopes. Subalpine fir,

whitebark pine, and limber pine grow at the higher elevations.

Some of the major wildlife species in this area are antelope,

mule deer, elk, mountain goat, bighorn sheep, coyote,

jackrabbit, shore birds, songbirds, and birds of prey. The major

game fish are various species of trout.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 5%

Grassland—private, 11%; Federal, 83%

Other—private, 1%

Nearly all of this area is federally owned grassland. The

grasses and shrubs on the lower slopes and in valleys are

grazed. Irrigated land in the valleys is used mostly for hay

and pasture, but potatoes and small grains also are grown. The

high mountain slopes are forested, and some lumber is

produced.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and

productivity of the soils, loss of nutrients, streambank erosion,

mass movement of soil caused by overuse of irrigation water,

conservation of soil moisture, and preservation of water quality.

Conservation practices on cropland generally include

irrigation water management, water-control structures,

irrigation system improvements, nutrient management, riparian

forest buffers, critical area plantings, and streambank

stabilization. Conservation practices on rangeland and pasture

generally include prescribed grazing, development of springs,

watering facilities, wells, pipelines, fencing, and brush

management. Cool-season grasses, both introduced and native,

are often planted to improve production and forage quality.

Renovation of old pastures may include chiseling, disking, and

applying fertilizer.

Conservation practices on forestland generally include forest

site preparation, forest stand improvement, and forest trails and

landings. These practices help to control surface compaction,

the erosion caused by concentrated flow, and sediment delivery

to streams. 

Figure 13-1: Location of MLRA 13 in Land Resource Region B.
of the United States 41

and foothills and is as much as 9,500 feet (2,895 meters) on

mountain crests.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Upper Snake (1704), 74 percent; Bear (1601), 19 percent; and

Great Salt Lake (1602), 7 percent. The Bear, Portneuf,

Blackfoot, Snake, and Teton Rivers all occur in this area.

Geology

The foothills and dissected plateaus and plains are mantled

by loess ranging from a few inches to tens of feet in thickness.

The underlying bedrock is mainly sedimentary and

metasedimentary rock and some volcanic rock. Lacustrine

deposits and deep alluvium fill some level valleys and basins.

The plains and plateaus are separated by many rugged but

discontinuous mountain ranges of folded sedimentary and

metasedimentary rocks. Alluvial fans occur on the plains and

valley floors at the foot of the mountains. Terraces occur along

most of the larger rivers and creeks. The area has not been

glaciated.

Climate

The average annual precipitation is mainly 12 to 25 inches

(305 to 635 millimeters) but can be as high as 48 inches (1,220

millimeters) at the highest elevations. Most of the precipitation

occurs as rain and snow in fall, winter, and spring. It is

dominantly snow in winter. A few high-intensity, convective

thunderstorms occur in summer. The minimum precipitation

occurs from midsummer through autumn. The average annual

temperature generally is 36 to 48 degrees F (2 to 9 degrees C),

but it is lower in the mountains. The freeze-free period averages

130 days and ranges from 90 to 175 days. On the high

mountains, however, freezing may occur every month of the

year.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.1%; ground water, 0.4%

Livestock—surface water, 0.0%; ground water, 1.3%

Irrigation—surface water, 65.6%; ground water, 32.0%

Other—surface water, 0.0%; ground water, 0.5%

The total withdrawals average 1,875 million gallons per day

(7,095 liters per day). About 34 percent is from ground water

sources, and 66 percent is from surface water sources.

Precipitation provides water for dryland farming and grazing,

but careful management is needed to make the best use of the

limited amount. Several large streams that flow through the area

supply water for irrigation, mainly outside the MLRA. Small

but important tracts are irrigated along the Bear, Portneuf,

Blackfoot, Snake, and Teton Rivers. The surface water is

primarily from snowmelt runoff and is soft and of very good

quality. The ground water is scarce, except near the large

streams with valley fill aquifers. The basalt aquifer beneath the

Snake River Plain also is a source of ground water. Many wells

and springs produce thermal water at temperatures that exceed

170 to 200 degrees F (76 to 95 degrees C). The ground water is

hard or moderately hard but is of good quality.

Soils

The dominant soil order in this MLRA is Mollisols. The

soils in the area dominantly have a frigid or cryic soil

temperature regime, a xeric soil moisture regime, and mixed

mineralogy. They generally are deep or very deep, well drained,

and loamy. Haploxerolls formed in loess and alluvium (Lanoak,

Newdale, Rexburg, and Ririe series) and colluvium (Hondoho

series) on foothills, terraces, and mountains. Argicryolls (Dranyon

series) formed in alluvium, colluvium, and residuum on

mountains and uplands. Haplocryolls (Driggs series) formed in

alluvium on alluvial fans and terraces. Haplocryolls (Pavohroo

series) formed in alluvium and colluvium on mountains.

Palecryolls (Robin series) and Haplocryolls (Tetonia and Rin

series) formed in loess on foothills and terraces.

Biological Resources

The rangeland in this MLRA supports grass-shrub

vegetation. Bluebunch wheatgrass is dominant. There are minor

amounts of Idaho fescue and Wyoming big sagebrush.

Arrowleaf balsamroot, prairie junegrass, Sandberg bluegrass,

Nevada bluegrass, oniongrass, slender wheatgrass, milkvetch,

lambstongue, fawnlily, phlox, penstemon, antelope bitterbrush,

rabbitbrush, snowberry, and low Oregon-grape are other

important plants. Scattered stands of Douglas-fir with some

aspen and bigtooth maple grow on north-facing slopes and on

the more moist soils. Lodgepole pine and subalpine fir grow at

the higher elevations.

Some of the major wildlife species in this area are mule deer,

moose, elk, beaver, muskrat, mink, rabbit, pheasant, sage

grouse, Hungarian partridge, sharp-tailed grouse, ruffed grouse,

blue grouse, and mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 30%

Grassland—private, 34%; Federal, 24%

Forest—private, 5%; Federal, 3%

Urban development—private, 2%

Water—private, 1%

Other—private, 1%
42

Nearly three-fourths of this area is in farms and ranches. The

rest, including the Fort Hall Indian Reservation, is federally

owned. About one-third of the area is dry-farmed, and wheat

and barley are the major crops. Some land along the large

streams is irrigated. It is used mainly for alfalfa hay, meadows,

and pasture, but some small grains and potatoes also are grown.

More than one-half of the area is rangeland. Less than one-tenth

of the area, consisting of high mountain slopes, is in forests that

produce some timber.

The major soil resource concerns are water erosion,

maintenance of the content of organic matter and productivity

of the soils, and conservation of soil moisture.

Conservation practices on irrigated cropland generally

include conservation crop rotations, crop residue management

(such as no-till and mulch till), surface roughening, nutrient

management, irrigation water management, and water- and

sediment-control basins. Conservation practices on

nonirrigated cropland generally include no-till systems that

reduce the need for summer fallow, crop residue management,

mulch till, deep tillage, cross-slope farming, nutrient

management, water- and sediment-control basins, and

terraces.

Conservation practices on rangeland and pasture generally

include prescribed grazing, spring development, watering

facilities, wells, pipelines, fencing, streambank restoration, and

brush management. Cool-season grasses, both introduced and

native, are often planted to improve production. Renovation of

old pastures may include chiseling, disking, and applying

fertilizer.

Conservation practices on forestland generally include

forest site preparation, forest stand improvement, and forest

trails and landings. These practices help to control surface

compaction, the erosion caused by concentrated flow, and

sediment delivery to streams. 
43

Figure C-1: Location of Land Resource Region C.

C—California Subtropical Fruit, Truck,

and Specialty Crop Region

This region is entirely in California (fig. C-1). It makes up

62,350 square miles (161,570 square kilometers). Most of the

people in California live in this region.

This region of low mountains and broad valleys has a long,

warm growing season and low precipitation. The average

annual precipitation ranges from less than 6 inches to 12 inches

(150 to 305 millimeters) in the San Joaquin Valley, 12 to 30

inches (305 to 760 millimeters) in areas along the coast south of

San Francisco and in the Sacramento River Valley, and 15 to 40

inches (380 to 1,015 millimeters) in areas along the coast north

of San Francisco. Very little precipitation falls from late in April

through October. The average annual temperature is 41 to 67

degrees F (5 to 20 degrees C). The lower temperatures occur at

the higher elevations. The freeze-free period averages 245 to

345 days in most of this region. It ranges from 125 days in the

higher mountains to 365 days in the valleys in the southern

part of the region.

The total withdrawals of freshwater in this region average

about 30,260 million gallons per day (114,535 million liters

per day). About 54 percent is from surface water sources, and 46

percent is from ground water sources. This land resource region

is one of six that use more than 30,000 million gallons per day

(113,550 million liters per day). Surface water is abundant in

the mountains of northern California. Federal and State water

projects have built reservoirs that store snowmelt runoff for

later use in the more heavily populated southern California.

Reservoir water is sent to the Sacramento-San Joaquin Delta via

the Sacramento River and is pumped out of the delta and into a

Federal (Delta-Mendota) and California canal system that

moves the water down to the southern terminus of the San

Joaquin Valley. The canal water is used for public supplies in

cities along the way, but most is used for irrigation. Ground

water is used for public supply and irrigation in the San

Joaquin Valley. About 79 percent of all water used in the State

is used for irrigation, and 17 percent is public supply. A little

over half of the public supply comes from ground water. Los

Angeles and San Diego obtain most of their water from the

Colorado River via canals.
44 Major Land Resource Areas

The soils in this region are dominantly Alfisols, Entisols,

Mollisols, and Vertisols. The dominant suborders are Xeralfs,

Xererts, and Xerolls, which are extensive on uplands and the

older terraces throughout the region. Fluvents, Orthents, and

Ochrepts on flood plains and alluvial fans are the most

important soils used for agricultural purposes in this region.

The soils in the region dominantly have a thermic soil

temperature regime, a xeric soil moisture regime, and mixed or

smectitic mineralogy.

Federal land makes up about 16 percent of this region. It

makes up about 48 percent of the part of the region in the

Southern California Mountains. This region has a wide variety

of crops and agricultural enterprises (fig. C-2). Citrus fruits,

other subtropical and tropical fruits, and nuts are the major

crops in the southern half of the region. Many kinds of

vegetables, grown mainly under irrigation, are produced

throughout the region. Rice, sugar beets, cotton, grain crops,

and hay also are important crops. Dairying is a major enterprise

near the large cities. Beef cattle production on feedlots and

rangeland also is important.

Many of the soils on flood plains and low terraces in the

valley of the San Joaquin River are affected by salts and must

be skillfully managed for good crop production. The

agricultural drainage water in this valley commonly has a high

salt load, and the salinity in receiving streams typically

increases in a downstream direction. Control of the water

erosion caused by rainfall and irrigation and maintenance of the

content of organic matter in the soils are soil resource concerns

throughout this agriculturally rich region. Wind erosion is a

hazard in the valley of the San Joaquin River and in some of the

coastal valleys. Irrigation water management is a priority in this

populous region, where agriculture and urban areas compete for

good-quality water. Salinity and the intrusion of saltwater into

aquifers are management concerns in the coastal valleys. 

Figure C-2: Lettuce and almond trees in an area of Land Resource Region C.
of the United States 45

Figure 14-1: Location of MLRA 14 in Land Resource Region C.

14—Central California Coastal Valleys

This area is entirely in California (fig. 14-1). It makes up

about 3,170 square miles (8,215 square kilometers). There are

three parts in the area. The northern part includes the cities of

Ukiah, Santa Rosa, and Napa. The central part includes all the

metropolitan areas surrounding San Francisco and San Pablo

Bay. The major cities in this part are San Francisco, Berkeley,

Vallejo, Oakland, and San Jose. The southern part includes the

towns of Santa Cruz, Monterey, and Carmel on the shores of

Monterey Bay. Hollister, the city of Salinas, and the

agriculturally important Salinas Valley are in inland areas in the

southern part. Interstate 80 ends on the San Francisco side of

the Bay Bridge. United States Highway 101 and California

State Highway 1 are scenic drives as well as major

thoroughfares in this area.

A number of tourist destinations are in this area, including

the cities of San Francisco, Napa, Oakland, and Monterey.

Alcatraz, the Golden Gate Bridge, the wineries in Napa Valley,

the Monterey Bay Aquarium, and the beaches on the Pacific

Ocean coastline are all tourist attractions. Moffett Field, the

United States Naval Fuel Depot and Naval Supply Station, and

the Oakland Army Base are in the San Francisco area. The

Presidio of Monterey and the Naval Postgraduate School are in

the Monterey Bay area. There are a number of national wildlife

management areas and State parks along the coastline and bays

in this area.

Physiography

This area is in the California Coast Ranges Section of the

Pacific Border Province of the Pacific Mountain System. It is a

network of gently sloping valley floors bordered by higher and

more sloping terraces and alluvial fans and by steep uplands.

Elevation ranges from sea level to 1,970 feet (600 meters), but it

is less than 985 feet (300 meters) in most of the area.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows: San

Francisco Bay (1805), 46 percent; Central California Coastal

(1806), 38 percent; and Klamath-Northern California Coastal

(1801), 16 percent. The Russian River flows through the

northern part of the area, and the Napa and Petaluma Rivers

empty into San Pablo Bay. The Salinas River is in the southern

part of the area. The Hetch Hetchy Aqueduct brings Sierra

Nevada Mountain water from the Yosemite area to the bay area

for municipal, public supply, and industrial uses. The aqueduct

empties into the Upper Crystal Springs Reservoir, in the San

Andreas Fault zone directly south of San Francisco.

Geology

With the possible exception of the Santa Maria Valley to the

south, the coastal valleys in this area are structural basins. The

elongated shape and northwest-southeast orientation of the

valleys are strongly controlled by right-lateral strike-slip

movement along a regional set of faults that includes the San

Andreas, Rogers Creek, Hayward, and Calaveras Fault Zones

and other potentially active and inactive faults. The San

Andreas Fault Zone is a transform boundary where the North

American plate is moving northwest relative to the Pacific

tectonic plate to the west. The probability of a large magnitude

earthquake is considered to be particularly high along the

Rogers Creek-Hayward Fault Zones, which together extend

from approximately Healdsburg, southeastward beneath San

Pablo Bay, towards Milpitas.

These coastal valleys are partly filled with unconsolidated

and semiconsolidated marine sedimentary rocks that were

deposited during periodic encroachment of the sea and with

unconsolidated nonmarine alluvial, flood-plain, alluvial-fan,

and hillslope deposits derived from bedrock weathered from the

adjacent uplands. Older, more consolidated eolian, lacustrine,

and terrace deposits also occur. The coarser, more permeable

nonmarine sand and gravel store relatively large volumes of

fresh ground water; these coastal basin aquifers are variably
46 Major Land Resource Areas

confined, semiconfined, and unconfined and are in areas at risk

of saltwater intrusion and overdraft.

Mesozoic and Tertiary bedrock exposed in the hills,

foothills, and uplands in this MLRA include the Sonoma

Volcanics exposed in and around Napa and Sonoma Valleys;

graywackes, chert, ophiolites, and other units of the Franciscan

Formation; metamorphics and granitics of the Salinian block

flanking the Salinas Valley; and sedimentary formations exposed

near the Salinas and Santa Maria Valleys. Landslides are common

in steep areas underlain by rocks weakened by faulting and

deformation (e.g., Central Belt Franciscan) and/or lack of

cementation (e.g., Tertiary sedimentary shale formations).

Climate

The average annual precipitation in this area is 11 to 66

inches (280 to 1,675 millimeters). The higher amounts of

precipitation occur at the higher elevations in the area north of

San Francisco. Most of the rainfall occurs as low- or moderateintensity, Pacific frontal storms during winter. This area is very

dry from mid spring to mid autumn. Snowfall is rare. The

average annual temperature is 56 to 61 degrees F (13 to 16

degrees C). The freeze-free period averages 315 days and ranges

from 265 to 365 days. It is longest near the coast, and it

becomes shorter with elevation.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 22.8%; ground water, 17.1%

Livestock—surface water, 0.1%; ground water, 0.5%

Irrigation—surface water, 15.3%; ground water, 37.9%

Other—surface water, 5.2%; ground water, 1.0%

The total withdrawals average 3,100 million gallons per day

(11,735 million liters per day). About 56 percent is from ground

water sources, and 44 percent is from surface water sources. The

low or moderate rainfall and local streamflow are inadequate for

present water needs. Water from adjoining MLRAs is brought in

for agriculture and for the domestic and industrial requirements

of the many large cities. For example, most of the public water

in the bay area is provided by an aqueduct from the Hetch

Hetchy Reservoir in the Sierra Nevada Mountains. The quality

of the water in this reservoir is excellent. The quality of the

water in the rivers in the valleys is not as good. Agricultural

runoff, municipal and industrial wastes, and irrigation return

flows are all sources of contamination of local surface water.

The major ground water sources in this area are the

alluvium and older sediments in the coastal valleys. Surface

water infiltrating from irrigated areas mixes with the shallow

ground water in this aquifer, so some of the water that is

pumped is a combination of surface and ground water. This

water is very hard and requires softening for public, municipal,

or domestic uses. It typically contains more than 1,000 parts per

million (milligrams per liter) total dissolved solids, which

exceeds the national drinking water standard. The yield of

ground water in the deeper alluvial deposits, especially in the

Santa Clara Valley, is declining, and the intrusion of seawater is

becoming a problem. Nitrate and pesticide contamination in

the shallow aquifer in the Salinas Valley also is becoming a

concern.

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, Mollisols, and Vertisols. The soils in the area

dominantly have a thermic soil temperature regime, a xeric soil

moisture regime, and mixed or smectitic mineralogy. They

generally are very deep, somewhat excessively drained to

somewhat poorly drained, and loamy or clayey. Haploxeralfs

(Arbuckle and Pleasanton series) and Xerofluvents (Metz and

Yolo series) formed in alluvium on alluvial fans and stream

terraces. Fluvaquents (Reyes series) formed in alluvium in

marshes. Xeropsamments (Oceano series) formed in eolian

deposits on dunes. Argixerolls (Chualar and Lockwood series)

and Haploxerolls (Elder, Mocho, Salinas, and Sorrento series)

formed in alluvium on alluvial fans and stream terraces.

Endoaquerts (Clear Lake series) formed in alluvium in basins

and swales. Haploxererts (Cropley series) formed in alluvium

on alluvial fans and flood plains.

Biological Resources

This area supports grasses, brush, and trees. Naturalized

annual grasses and forbs are dominant in many areas. Soft

chess, wild oats, bromes, fescues, filaree, burclover, and some

remnant perennials are the major species. Scattered valley oak

grows on the well drained soils. Saltgrass, iodinebush, and

other salt-tolerant plants grow in tidal areas. Some areas have a

few remnant stands of redwood trees.

Some of the major wildlife species in this area are turkey,

California quail, mourning dove, meadowlark, blackbird, whitecrowned sparrow, white-tailed kite, robin, mockingbird, thrush,

brown towhee, and cedar waxwing.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 19%

Grassland—private, 23%; Federal, 3%

Forest—private, 10%; Federal, 1%

Urban development—private, 28%

Water—private, 9%

Other—private, 7%
of the United States 47

Most of the MLRA is in farms and ranches. The acreage used

for urban development is increasing rapidly. The gently sloping

soils in the valleys are intensively used for many kinds of

crops. Truck crops, wine grapes, strawberries and other fruits,

cut flowers, small grains, hay, and pasture are the principal

crops grown on irrigated land. Small grains are the principal

crops in dry-farmed areas. Dairy farming is an important

enterprise near the large cities. The more sloping fans and

foothills, making up one-fourth or more of the area, are in

native range used for livestock grazing. Sites along streams are

susceptible to flooding and bank cutting.

The major soil resource concerns are erosion, maintenance of

the content of organic matter in the soils, and water quality. The

erosion hazard is slight on the soils in valleys and on terraces

and benches of the valleys, except where improper irrigation

practices are more damaging than rainfall. If the surface is

unprotected in winter, the hazard of sheet and gully erosion is

severe on the sloping soils on coastal terraces and benches and

on upland soils. Salinity and encroachment of seawater into

ground-water basins are problems in areas of valleys near sea

level.

The conservation practices that are important on cropland

are those that control erosion. These practices include mulching,

cover crops, irrigation water management, and tailwater return

systems on the steeper irrigated slopes. The conservation

practices that are important on dairy farms are manure-handling

systems, including nutrient management. Prescribed grazing,

fencing, and water management are the most important

practices on rangeland and other grazing land. 

Figure 15-1: Location of MLRA 15 in Land Resource Region C.

15—Central California Coast Range

This area is entirely in California (fig. 15-1). It makes up

about 17,840 square miles (46,235 square kilometers). The

town of Clearlake is almost in the center of the northern part

of this MLRA, and the towns of Suisun City and Benicia are at

the south end of the northern half. The towns of Martinez,

Concord, Pleasant Hill, and Alamo are in the north end of the

southern half of the area. The towns of Atascadero and Paso

Robles are in the south end of the southern half. The Hunter

Liggett and Camp Roberts Military Reservations, Vandenburg

Air Force Base, and Santa Ynez Indian Reservation are in the

southern half. Parts of the Mendocino and Trinity National

Forests occur along the west edge of the northern half of the

area. The Los Padres National Forest is in the south end of the

southern half. Interstate 80 crosses the junction of the northern

and southern halves of the area, directly north of the Carquinez

Straits, which connect the Sacramento-San Joaquin Delta with

San Pablo Bay.

Physiography

All of this area is in the Pacific Border Province of the

Pacific Mountain System. Most of this MLRA is in the

California Coast Ranges Section of the province. The extreme

northern end is in the Klamath Mountains Section, and the

southwest corner is in the Los Angeles Ranges Section. The

MLRA is an area of gently sloping to steep, low mountains.

The coastal plains are narrow and discontinuous, and stream

valleys are narrow and widely separated. Elevation ranges from

sea level to 2,650 feet (810 meters) in most of the area, but it is

4,950 feet (1,510 meters) in some of the mountains.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Central California Coastal (1806), 48 percent; Sacramento

(1802), 20 percent; San Francisco Bay (1805), 12 percent;

Tulare-Buena Vista Lakes (1803), 9 percent; San Joaquin
48 Major Land Resource Areas

(1804), 8 percent; and Klamath-Northern California Coastal

(1801), 3 percent. Clear Lake and Lake Berryessa are in the

northern half of the area. This half is drained by Sacramento

River tributaries, such as Cache Creek and Putah Creek. Few

perennial streams are in the southern half of the area. The

streams in this half typically drain to the Pacific Ocean.

Geology

The landscape and geology of the Coast Range are strongly

controlled by right-lateral strike-slip movement along the San

Andreas and other active and inactive faults that dissect the

range. The northwest-southeast orientation of the river courses

and intervening ridges reflects the area’s youthful geologic

history along a transform boundary, where the Pacific tectonic

plate is moving northwest relative to the North American plate

to the east. Recent and historic earthquakes centered in the

Coast Range attest to the active plate motion and associated

seismicity that continue to shape the landscape. These quakes

include the 1906 San Francisco earthquake, the Loma Prieta

earthquake of 1989, and numerous large earthquakes centered

near Parkfield (most recently in September 2004).

Most of the Northern Coast Range is underlain by deformed

and metamorphosed sandstones and shales of the Franciscan

Formation, which were deposited offshore during the Mesozoic,

conveyed eastward towards the Franciscan trench, and then

subducted as a series of terranes beneath the old ocean floor at

the continental margin. Narrow bands of serpentine-bearing

ophiolites, representing remnants of an old ocean floor, separate

these Franciscan terranes from the relatively undisturbed marine

sedimentary rocks of the Great Valley sequence, which is

exposed along the eastern margin of the Northern Coast Range.

The Central Belt of the Franciscan Formation consists of a

highly disturbed mélange, which was intensely sheared and

deformed when strike-slip movement along the San Andreas

Fault replaced subduction through the Franciscan trench

beginning very roughly 30 million years ago. Mélange consists

of relatively resistant metamorphic rocks and boulders

“floating” in intensely sheared and weak matrix material. Steep

areas underlain by Franciscan mélange tend to be highly prone

to landslides.

The geology of the Southern Coast Range is highly varied.

It includes bands of the Franciscan Formation along the

northeast edge of the San Andreas Fault and along the southeast

edge of the Nacimiento Fault in the Santa Lucia Range;

Mesozoic granitics of the Salinian block, which were “rafted”

hundreds of miles to their present locations in Pinnacles

National Monument and elsewhere in the Coast Range by

movement along the transform boundary; and Tertiary and

Pleistocene marine and nonmarine sedimentary formations,

including the diatomaceous Monterey Shale, which is a

significant source rock for oil reserves.

Climate

In the part of this MLRA south of San Francisco, the average

annual precipitation is 6 to 20 inches (150 to 510 millimeters)

and snowfall is rare. The northern half of the MLRA can be

divided into two rainfall and snowfall zones. In the southern

half of the part of the MLRA north of San Francisco, the

average annual precipitation is 18 to 40 inches (455 to 1,015

millimeters) and snowfall is rare. In the northern half of the part

north of San Francisco, the average annual precipitation is 40

to 79 inches per year (1,015 to 2,005 millimeters) and snowfall

is common. Precipitation is evenly distributed throughout fall,

winter, and spring but is very low in summer. Coastal areas

receive some moisture from fog in summer. Most of the rainfall

occurs as low- or moderate-intensity, Pacific frontal storms

during the period October to May. The average annual

temperature is 51 to 66 degrees F (10 to 19 degrees C),

decreasing from south to north. The freeze-free period averages

275 days and ranges from 180 to 365 days, decreasing in length

with elevation and from south to north.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 51.6%; ground water, 13.3%

Livestock—surface water, 1.7%; ground water, 0.5%

Irrigation—surface water, 19.9%; ground water, 7.4%

Other—surface water, 4.5%; ground water, 1.1%

The total withdrawals average 680 million gallons per day

(2,575 million liters per day). About 22 percent is from ground

water sources, and 78 percent is from surface water sources. The

low or moderate rainfall and moderate streamflow limit

agriculture to dryfarming in most of the area. Reservoirs are

used to store surface runoff for use during most of the year

when streams are low. Surface water generally is of good quality

and is suitable for almost all uses.

Ground water is limited in this area. There are some wells in

alluvium and older sediments in the major river valleys and in

low areas. This water is very hard and typically requires

softening prior to its use. Levels of total dissolved solids

exceed the national drinking water standard of 500 parts per

million (milligrams per liter). Igneous rocks in this area have

some ground water. Well yields are low since the water is in

joints and fractures in the bedrock. Few test results are

available, so little is known about the quality of this water.

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, Mollisols, and Vertisols. The soils in the area
of the United States 49

dominantly have a thermic soil temperature regime, a xeric soil

moisture regime, and mixed or smectitic mineralogy. They

generally are very shallow to deep, somewhat excessively

drained or well drained, and loamy or clayey. Haploxeralfs

(Vallecitos series), Xerorthents (Cieneba, Gaviota, and Shedd

series), Argixerolls (Henneke, Los Gatos, and Los Osos series),

Haploxerepts (Millsholm series), Dystroxerepts (Maymen

series), Haploxerolls (Nacimiento, San Benito, Santa Lucia, and

Sheridan series), and Haploxererts (Altamont, Diablo, and

Sehorn series) formed in residuum on hills and mountains.

Biological Resources

This area supports grasses, grass-oak, and shrub vegetation.

Naturalized annuals, including soft chess, bromes, fescues, wild

oats, filaree, and burclover, characterize the open and oak

woodlands. Blue oak, valley oak, and canyon live oak are the

dominant trees. California sagebrush, coyotebrush, chamise,

manzanita, ceanothus, and scrub oak are the major brush

species. Forests of Douglas-fir, madrone, grand fir, tanoak, and

bigleaf maple and a few remnant stands of redwood trees are

along the west side of the Coast Range. Stands of ponderosa

pine with madrone, black oak, live oak, California buckeye,

manzanita, and ceanothus are on the drier sites.

Some of the major wildlife species in this area are blacktailed deer, feral pig, turkey, blue grouse, valley quail, and

band-tailed pigeon. The species of fish in the area include trout,

largemouth bass, bluegill, minnow, stickleback, channel catfish,

bullhead, carp, sculpin, steelhead, salmon, and crappie.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 7%

Grassland—private, 48%; Federal, 13%

Forest—private, 21%; Federal, 4%

Urban development—private, 4%

Water—private, 2%

Other—private, 1%

More than four-fifths of this area consists of private land,

mainly in farms and ranches. The rest generally is federally

owned. About one-tenth of the area is used for dry-farmed grain,

and slightly more than three-fifths is in range of native grasses

and brush. Open woodland, also used for grazing, makes up

about one-fourth of the area. A small acreage is used for urban

development.

The major soil resource concerns are erosion, maintenance

of the content of organic matter in the soils, water quality, and

low infiltration rates resulting from hydrophobic soils. If the

surface is unprotected in winter, the hazard of sheet and gully

erosion is severe on the sloping soils on terraces and benches

and on upland soils.

The conservation practices that are important on cropland

include leaving crop residue on the surface. Prescribed grazing,

fencing, and water management are the most important

practices on rangeland and other grazing land. 

Figure 16-1: Location of MLRA 16 in Land Resource Region C.

16—California Delta

This area is entirely in California (fig. 16-1). It makes up

about 805 square miles (2,080 square kilometers). It has no

cities or large towns. Suisun, Honker, and Grizzly Bays and

Franks Tract State Recreation Area are in the area. The delta

is above the San Pablo and San Francisco Bays. It formed at the

junction of the two major rivers draining the Central Valley of

California—the Sacramento River to the north and the San

Joaquin River to the south. A major pumping plant at Tracy

lifts water from the delta into the California and Delta-Mendota

Canals, which take the water south to farms in the Central
50 Major Land Resource Areas

Valley and Tulare Lake Basin and to southern California

cities. During periods of low flow, the plant causes a flow

reversal and brackish water from San Pablo Bay can move up

into the delta. A system of levees keeps the farmland from

flooding.

Physiography

Most of this area is in the California Trough Section of the

Pacific Border Province of the Pacific Mountain System. A

small part at the west edge of the area is in the California Coast

Ranges Section of the same province and division. This MLRA

was originally the conjoined flood plain along the Sacramento

and San Joaquin Rivers. As sediment from these rivers built up

in San Pablo Bay, a delta formed, creating many streams that

divide this nearly level area into “islands.” Strong levees and

drainage systems are needed to protect the islands from

flooding. Elevation of the islands ranges from below sea level

to slightly above sea level.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows: San

Joaquin (1804), 47 percent; Sacramento (1802), 35 percent; and

San Francisco Bay (1805), 18 percent.

Geology

This area is underlain by interbedded marine, estuarine, and

fine grained nonmarine sediments transported to the delta by

the Sacramento and San Joaquin Rivers as they flowed into San

Pablo Bay. As the sediments built up, a delta formed and

freshwater mixed with brackish water in marshes and on flood

plains. As the marsh vegetation became covered with new

sediments, the organic matter content in the soils built up to

very high levels. When drained and exposed to the air, these

peaty soils oxidize and shrink and then subside.

Climate

The average annual precipitation in this area is 12 to 21

inches (305 to 535 millimeters). Summers are dry. Most of the

rainfall occurs as low- or moderate-intensity, Pacific frontal

storms during the period October to May. Snowfall is rare in

this area. The average annual temperature is 59 to 61 degrees F

(15 to 16 degrees C). The freeze-free period averages 345 days

and ranges from 330 to 360 days.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 0.2%; ground water, 0.1%

Irrigation—surface water, 79.6%; ground water, 19.4%

Other—surface water, 0.6%; ground water, 0.2%

The total withdrawals average 720 million gallons per day

(2,725 million liters per day). About 20 percent is from ground

water sources, and 80 percent is from surface water sources.

Almost all of the water is used for agriculture. Most of it comes

from the many sloughs and waterways that cross the area.

Controlling salinity and the intrusion of saltwater is a major

concern.

The small amount of ground water used for irrigation on the

east side of this area is pumped from the alluvium and older

sediments in the Central Valley. This water is hard or very hard

and generally contains about 300 parts per million (milligrams

per liter) total dissolved solids. Nitrates from agricultural runoff

can contaminate this shallow ground water.

Soils

The dominant soil orders in the MLRA are Entisols,

Histosols, and Mollisols. The soils in the area dominantly have

a thermic soil temperature regime, an aquic soil moisture

regime, and mixed mineralogy. They generally are very deep,

poorly drained or very poorly drained, and clayey. Fluvaquents

formed in alluvium on flood plains and deltas (Valdez series)

and in marshes (Reyes series). Endoaquepts (Tamba series)

formed in alluvium in salt marshes. Haplosaprists formed in

organic material in salt marshes (Joice series) and freshwater

marshes (Kingile and Rindge series). Endoaquolls (Egbert,

Gazwell, Peltier, and Ryde series) formed in alluvium in basins,

marshes, and sloughs and on deltas.

Biological Resources

This area supports marsh vegetation. Fat-hen saltweed, brass

buttons, alkali bulrush, cattails, tules, saltgrass, and pickleweed

characterize the area.

Some of the major wildlife species in this area are small

mammals, river otter, beaver, and various songbirds. The

species of fish in the area include striped bass, black bass,

crappie, sunfish, catfish, salmon, steelhead, varieties of

minnows, and sturgeon. The area is extremely important for

wintering waterfowl, neotropical migrants, and year-round

shore birds.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 55%

Grassland—private, 7%; Federal, 1%

Urban development—private, 3%

Water—private, 17%

Other—private, 17%

More than one-half of this area is farmed. The most

important crops are asparagus, sugar beets, potatoes, corn,

grain, and hay grown under intensive management. Fruit trees,
of the United States 51

mainly pear trees, and some grapes are grown on slopes of the

protecting levee system. Erosion of the levees by wave action is

a continuous problem. Subsidence of the peaty and mucky soils

also is a problem.

The major soil resource concern is the subsidence caused

mainly by oxidation, wind erosion, and shrinkage of organic

soils. The most important conservation practice on cropland is

controlling the water table by applying irrigation and drainage

water management and by flooding the fields during idle

periods. Other important practices are conservation cropping

systems, selection of water-tolerant crops for planting, and

nutrient and pest management. 

Figure 17-1: Location of MLRA 17 in Land Resource Region C.

17—Sacramento and San Joaquin

Valleys

This area is entirely in California (fig. 17-1). It makes up

about 18,650 square miles (48,330 square kilometers). From

north to south, the major towns or cities in this area are

Redding, Red Bluff, Chico, Yuba City, Marysville, Woodland,

Davis, Vacaville, Fairfield, Sacramento, Stockton, Modesto,

Merced, Madera, Firebaugh, Fresno, Hanford, Visalia, and

Bakersfield. Interstate 5 and California State Highway 99 both

traverse the entire length of the area. Interstate 80 crosses the

midpoint of the area in Sacramento. The MLRA includes Beale,

McClellan, Mather, Travis, and Castle Air Force Bases; the

Sacramento Army Depot, Lemoore Naval Air Station, and Naval

Petroleum Reserves #1 and #2; and numerous national wildlife

refuges. The area is locally known as the Central Valley and is

part of the Pacific migratory waterfowl flyway.

Physiography

All of this area is in the Pacific Border Province of the

Pacific Mountain System. Almost all of the area is in the

California Trough Section. Small areas along the western

border are in the California Coast Ranges Section. This area

includes the valley basins adjacent to the Sacramento and San

Joaquin Rivers, fans and flood plains of tributary streams, and

terraces and foothills around the edge of the valleys. Elevation

ranges from sea level to 660 feet (200 meters) in the foothills

surrounding the Central Valley. The valley floor is almost flat,

and relief is small even along the borders of the area.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Tulare-Buena Vista Lakes (1803), 42 percent; Sacramento

(1802), 31 percent; and San Joaquin (1804), 27 percent. The

Sacramento and San Joaquin Rivers are in this MLRA. The

major water-supply reservoirs on the Sacramento River and its

tributaries are just outside the north and east boundaries of the

area. A stretch of the American River below Folsom Lake has

been designated as a National Wild and Scenic River. Two

major canals are in this area. The State-owned California

Aqueduct and the Federal Delta-Mendota Canal move water

from northern California, from the California Delta, to Buena

Vista Lake directly southwest of Bakersfield.

Geology

California’s Great Valley is underlain by as much as 8 or 9

miles of sediments derived from the adjacent uplands and

deposited in a variety of marine and nonmarine environments.

The Great Valley began to separate from the open ocean

roughly 150 million years ago, when subduction of Franciscan

marine sediments and volcanics beneath the edge of the old

ocean floor jacked it up and created a barrier to movement of

sediments. The oldest sediments were derived in large part from

the early Sierra Nevada volcanoes and deposited in a deeper

marine environment. The composition of the sediments shifted

as the volcanic cover was stripped off, exposing the granites of

the Sierra Nevada Batholith to erosion. At the same time, the

valley started to fill and deposition was occurring in an
52 Major Land Resource Areas

increasingly shallow marine environment, particularly in the

Sacramento Valley, where shallow marine environments started

giving way to nonmarine depositional processes roughly 50

million years ago. The interbedded layers of clays, sands, silts,

and gravel strongly influence subsurface hydrology and are a

source of gas reserves in the Sacramento Valley and oil and gas

reserves in the deeper San Joaquin Valley.

The uppermost sediments reflect a recent history of

sedimentation in a variety of nonmarine depositional

environments. The finer grained deposits are typically

associated with flood plains, basins, and lakes. The coarser

grained sands and gravel are deposited in stream channels and

across alluvial fans. Erosional remnants of gravelly stream

terraces and older sedimentary formations also occur, especially

along the edges of the valley. Almost all of the surface of this

area is covered by recent alluvial deposits. There are some

sandy areas, but most of the deposits are flood-plain sediments

with a texture of silt to clay. Some gravel occurs in terraces and

abandoned channels along modern streams and rivers draining

from the surrounding mountains down into this area. Some

marine sediments are buried beneath these thick alluvial

deposits. Sutter Butte, in the northern part of the Sacramento

River Valley, consists of the eroded remnants of a volcano.

Climate

The average annual precipitation is 5 to 12 inches (125 to

305 millimeters) in the San Joaquin Valley. The Tulare Basin, at

the southern end of this MLRA, typically receives less than 6

inches (150 millimeters) of rainfall per year. The average annual

precipitation is 12 to 30 inches (305 to 760 millimeters) in

most of the Sacramento Valley. It is 40 inches (1,015

millimeters) at the higher elevations on the edges of the valley

at the north end. Summers are long, hot, and dry, and winters are

cool and rainy. Most of the rainfall occurs as low- or moderateintensity, Pacific frontal storms from October to May. Snow is

very rare in this MLRA but has occurred in the Sacramento

Valley from Sacramento to points farther north. The average

annual temperature is 59 to 67 degrees F (15 to 20 degrees C),

decreasing from south to north. The freeze-free period averages

325 days and ranges from 280 to 365 days, decreasing in length

with elevation and from south to north.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.5%; ground water, 6.5%

Livestock—surface water, 0.4%; ground water, 0.7%

Irrigation—surface water, 51.5%; ground water, 38.1%

Other—surface water, 0.7%; ground water, 1.5%

The total withdrawals average 22,755 million gallons per day

(86,240 million liters per day). This is the largest amount of

water used in any MLRA. About 47 percent is from ground

water sources, and 53 percent is from surface water sources.

Because of the low rainfall and relatively small flow from

streams, water is scarce in many parts of this area. Water for

irrigated crops comes from stream diversions, wells, and canals

of organized irrigation districts that obtain most of their water

from State and Federal water systems. The Sacramento River

supplies the most water for use in this area. The river water is

hard but is of good quality and is suitable for drinking after

minimal treatment. The tributaries of the San Joaquin River

draining the Sierra Nevada Mountains to the east have water of

excellent quality. Water in the lowland streams is often

degraded by sediment and salts from agricultural irrigation and

drainage and municipal and industrial waste discharges,

especially during the summer low-flow season.

The deep alluvium and older sediments filling the

Sacramento and San Joaquin Valleys are the sources of ground

water in this area. Water beneath the Sacramento basin is hard

and has a median concentration of about 300 parts per million

(milligrams per liter) total dissolved solids. Boron

concentrations exceed the national standard for drinking water

in the southwest corner of the Sacramento basin. The boron

comes from thermal springs in the Coast Range and upward

seepage of ground water from marine sediments.

Water quality varies in the San Joaquin basin. The water is

much fresher on the east side of the valley as it comes off the

granite rocks in the Sierra Nevada Mountains. Total dissolved

solids of 200 parts per million (milligrams per liter) are not

uncommon on the east side of the valley, while levels 10 times

higher typically occur on the west side, where recharge is from

marine sediments in the Coast Range. A confining layer called

the Corcoran Clay separates the water described above from

deeper, confined ground water. The water below the Corcoran

Clay has a more uniform level of total dissolved solids of about

1,000 parts per million (milligrams per liter). The ground water

beneath the San Joaquin basin is hard, and boron concentrations

may exceed the national standard for drinking water. The boron

comes from thermal springs in the Coast Range and upward

seepage of ground water from marine sediments. Ground

subsidence has been significant (more than 20 feet in some

areas) on the San Joaquin Valley floor because of historic

excessive pumping of ground water aquifers, which has resulted

in consolidation of the aquifers.

Soils

The dominant soil orders in the MLRA are Alfisols,

Aridisols, Entisols, Mollisols, and Vertisols. The soils in the

area dominantly have a thermic soil temperature regime, an

aridic or xeric soil moisture regime, and mixed or smectitic

mineralogy. They generally are very deep, well drained or

moderately well drained, and loamy or clayey. Some soils are

shallow to a duripan. Durixeralfs (Redding and San Joaquin

series) and Palexeralfs (Newville series) formed in alluvium on
of the United States 53

terraces. Haplocambids (Cerini and Panoche series) formed in

alluvium on alluvial fans. Haplargids (Milham series) formed in

alluvium on alluvial fans and terraces. Xeropsamments (Delhi

series), Xerorthents (Hanford series), and Torriorthents (Hesperia

and Kimberlina series) formed in alluvium on flood plains, fans,

and terraces. Haploxerolls (Grangeville and Nord series) formed

in alluvium on alluvial fans and flood plains. Haploxererts

(Capay series) formed in alluvium on alluvial fans and flats.

Very poorly drained Endoaquerts (Willows series) formed in

alluvium in basins.

Biological Resources

This area supports naturalized annuals and scattered trees.

Wild barley, wild oats, soft chess, ripgut brome, red brome,

foxtail fescue, burclover, and filaree are the dominant species.

Scattered oaks on terraces and oak, willow, and cottonwood

grow along the rivers and streams and in overflow areas.

Saltgrass, along with such shrubs as iodinebush and Australian

saltbush, grow on saline-sodic soils on terraces and in basins.

The major wildlife species include jackrabbit, coyote, fox,

ground squirrel, pocket gopher, and various songbirds. The

species of fish include salmon, striped bass, steelhead, shad,

sturgeon, largemouth bass, smallmouth bass, bluegill, and

catfish. Portions of the area are extremely important for

wintering waterfowl and seasonally neotropical migrants.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 58%

Grassland—private, 25%; Federal, 2%

Forest—private, 2%

Urban development—private, 8%

Water—private, 1%

Other—private, 4%

More than four-fifths of the area is in farms and ranches. The

acreage used for urban development is increasing rapidly.

Three-fourths or more of the cropland is irrigated. The cropland

in this MLRA represents about one-third of the cropland in

California, and the irrigated cropland represents more than fourfifths of the irrigated land in the State. Cotton, nuts, grapes, hay,

grain, pasture, rice, alfalfa, citrus, and truck crops, including

tomatoes, are the principal crops in irrigated areas. The more

sloping nonirrigated cropland is used for dry-farmed grain.

About a third of the MLRA is in areas of native grasses, brush,

and open woodland used mostly for grazing.

The major resource concerns are maintenance of the content

of organic matter in the soils, water quality, irrigation-induced

erosion, wind erosion, and irrigation water management. If the

plant cover is removed, water erosion is a hazard on the more

sloping soils on terraces and the hazard of wind erosion is

severe on the sandy, wind-modified soils in the San Joaquin

Valley. In areas of low precipitation, maintaining a favorable

salinity status in the root zone is a resource concern.

The conservation practices that are important on cropland

are crop rotations, minimum tillage, and the utilization of crop

residue to maintain good soil tilth and favorable soil structure.

Wind abrasion is a critical problem during crop establishment

on coarse textured soils. It can be controlled by crop residue

management and windbreaks. In areas where the amount of

rainfall is too low to leach salts from the soils, all leaching must

be accomplished with the use of irrigation water.

 The important conservation practices on dairy farms include

manure-handling systems, including nutrient management. The

important conservation practices on grazing land include

prescribed grazing, fencing, and water management. 

Figure 18-1: Location of MLRA 18 in Land Resource Region C.

18—Sierra Nevada Foothills

This area is entirely in California (fig. 18-1). It makes up

about 8,160 square miles (21,145 square kilometers). The towns

of Auburn, Folsom, Cameron Park, Oroville, and Ione are in the
54 Major Land Resource Areas

north half of this area. The western edges of the Lassen, Plumas,

Sierra, and Sequoia National Forests are in this MLRA. The

Tule Indian Reservation is in the southern part of the area.

California State Highway 49 traverses the middle third of this

MLRA, and Interstate 80 crosses the midpoint.

Physiography

This area straddles the boundary between two physiographic

provinces in the Pacific Mountain System. Most of the western

half is in the California Trough Section of the Pacific Border

Province. Most of the eastern half is in the Sierra Nevada

Section of the Cascade-Sierra Mountains Province. The Sierra

Nevada Mountains are a fault-block mountain range. The fault

on the east side of the mountains created a steep face of alpine

summits, but the west side has a more gentle slope from east to

west. This MLRA is at the toe of that gentle east-west slope. It

is an area of rolling to steep dissected hills and low mountains.

The stream valleys are narrow and fairly steep. Elevation

generally ranges from 660 to 1,650 feet (200 to 505 meters), but

it is 3,950 feet (1,205 meters) on some isolated mountain peaks.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows: San

Joaquin (1804), 36 percent; Tulare-Buena Vista Lakes (1803),

35 percent; Sacramento (1802), 26 percent; and Northern

Mojave-Mono Lake (1809), 3 percent. Many of the streams

crossing this area were hydraulically mined for placer gold

from 1849 to 1900. Some of the major streams draining the

Sierra Nevada Mountains from north to south in the area

include the Butte, Feather, Yuba, American, Cosumnes,

Mokelumne, Tuolumne, San Joaquin, Kings, and Kern Rivers.

Numerous Federal and State water project reservoirs are in this

MLRA, including Lakes Oroville, Collins, Englebright, Camp

Far West, Folsom, Comanche, Pardee, New Hogan, New

Melones, Don Pedro, McClure, Millerton, Pine Flat, Kaweah,

Success, and Isabella.

Geology

The northernmost end of this area is underlain dominantly

by volcanic mudflow and pyroclastic rocks of the Tuscan

Formation, which was derived from the eruption of Cascade

volcanoes during the Pliocene, roughly 3 to 4 million years

ago. South of about Oroville, the foothills are underlain by

Mesozoic-age, metamorphosed marine sedimentary and

volcanic rocks emplaced as terranes when the subduction trench

was located in the vicinity of the present-day Sierra Nevada

Mountains. Discrete granitic plutons are intruded through the

older Mesozoic metamorphics in the northern part of the area,

and a thin band of Tertiary sedimentary formations is exposed

along the eastern edge from the Cosumnes River south. From

around Merced southward, the foothills are underlain

dominantly by Mesozoic granites of the Sierra Nevada

Batholith, with local exposures of gabbro, metavolcanics, and

other metamorphics. Tertiary sedimentary formations and

Quaternary alluvial terrace deposits extend westward from the

granitics in the vicinity of Bakersfield.

Climate

The average annual precipitation is 18 to 45 inches (455 to

1,145 millimeters) in most of this area. It increases from south

to north and with elevation. It is as little as 8 inches (205

millimeters) in the extreme southern end of the area and as

much as 68 inches (1,725 millimeters) in the extreme northern

end. Summers are hot and dry, and winters are cool and moist.

Most of the rainfall occurs as Pacific frontal storms during the

period October to May. The average annual temperature is 47 to

67 degrees F (8 to 20 degrees C). The freeze-free period

averages 275 days and ranges from 180 to 365 days, decreasing

in length from south to north and with elevation.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 48.0%; ground water, 8.4%

Livestock—surface water, 2.2%; ground water, 0.7%

Irrigation—surface water, 32.8%; ground water, 1.6%

Other—surface water, 5.2%; ground water, 1.1%

The total withdrawals average 120 million gallons per day

(455 million liters per day). About 12 percent is from ground

water sources, and 88 percent is from surface water sources. The

moderate rainfall and intermittent streamflow are the major

water sources. Numerous stock ponds are throughout the area,

but little has been done to construct small reservoirs for

irrigation. The major reservoirs in this area store water for use

outside the area. The surface water generally is of very good

quality and is suitable for almost all uses with little to no

treatment.

Ground water supplies are small and mostly untapped. Some

water can be obtained from joints and fractures in the volcanic

rocks in the northeast corner of the area. No data are available

on the quality of this ground water. Shallow wells can be

developed in the alluvial deposits along the major streams

crossing the area. This ground water is similar to the surface

water and is suitable for almost all uses with minimal treatment.

Some ground water can be obtained from wells in the alluvium

and older sediments along the western edge of this area on the

fringes of the Central Valley. This water is hard but is of good

quality. It generally has a median level of total dissolved solids

of about 200 parts per million (milligrams per liter).

Soils

The dominant soil orders in the MLRA are Alfisols, Entisols,

Inceptisols, and Mollisols. The soils in the area dominantly
of the United States 55

have a thermic soil temperature regime, a xeric soil moisture

regime, and mixed mineralogy. They generally are very shallow

to deep, well drained or somewhat excessively drained, and

loamy. Haploxeralfs (Ahwahnee, Auberry, Blasingame,

Coarsegold, and Sobrante series), Xerorthents (Cieneba series),

Haploxerepts (Auburn, Toomes, and Vista series), Argixerolls

(Arujo and Supan series), and Haploxerolls (Pentz and Walong

series) formed in residuum on mountains, foothills, and

footslopes.

Biological Resources

This area supports naturalized annual grasses, shrubs, and

trees. Soft chess, wild oats, filaree, burclover, ripgut brome, and

foxtail fescue are the dominant species on grassland. Some

areas have an overstory of blue oak and foothill pine occurring

as scattered individual trees to very dense stands. Scrub live

oak is an important component in the overstory. Chamise,

manzanita, wedgeleaf ceanothus, yerba santa, and poison oak

are dominant on brushland. Scattered stands of ponderosa pine,

mixed with manzanita and black oak, are at the higher

elevations.

Some of the major wildlife species in this area are blacktailed deer, mountain lion, coyote, gray fox, raccoon, porcupine,

skunk, jackrabbit, ground squirrel, pocket gopher, brown rat,

field mouse, valley quail, band-tailed pigeon, red-headed

woodpecker, mourning dove, mallard, cinnamon teal, wood

duck, and rattlesnake. The species of fish in the area include

black bass, bluegill, crappie, trout, salmon, steelhead, and

catfish.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—private, 51%; Federal, 10%

Forest—private, 28%; Federal, 4%

Urban development—private, 4%

Water—private, 2%

Other—private, 1%

Production of livestock on rangeland is the main enterprise

in this area. A significant acreage is brushland or openland

hardwood forest. A small acreage is cropland. In the past most

of the cropland in the area was used for dry-farmed grain, but

more and more small tracts are now used for nuts, grapes, and

other kinds of fruit grown under sprinkler, micro, and drip

irrigation systems.

The major soil resource concerns are erosion, maintenance

of the content of organic matter in the soils, water quality, and

low infiltration rates resulting from hydrophobic soils. The

hazard of erosion is moderate or severe if the plant cover is

removed by overgrazing, cultivation, or fire. If the surface is

unprotected in winter, the hazard of sheet and gully erosion is

severe on the sloping soils on terraces and benches and on

upland soils.

The conservation practices that are important on cropland

include crop residue management, cover crops, and irrigation

water management. Prescribed grazing, fencing, and stock water

development are the most important practices on rangeland and

other grazing land.

The conservation practices that are important in developing

urban land include controlling erosion on and around sites for

houses and roads. The important erosion-control practices are

methods of phasing construction that maintain as much of the

native vegetation as possible, mulch and geotextile erosion

blankets, a temporary cover of vegetation, and sediment-control

systems, including sediment-debris basins and traps, silt fences,

fiber rolls, and straw wattles. 

Figure 19-1: Location of MLRA 19 in Land Resource Region C.

19—Southern California Coastal Plain

This area is entirely in California (fig. 19-1). It makes up

about 4,120 square miles (10,675 square kilometers). It is

considered the Citrus Belt of California. Ventura, Los Angeles,

and San Diego are in this MLRA. Interstate 5 parallels the coast
56 Major Land Resource Areas

through this area, and Interstate 15 parallels Interstate 5 inland

in the foothills. Interstate 10 crosses the northern end of the

area, and Interstate 8 crosses the southern end. Numerous other

interstate segments are around the two major cities in this

populous MLRA. The area includes the San Clemente, Camp

Pendleton, and Miramar Naval Air Station Military

Reservations; the Santa Monica Mountains National

Recreation Area; and the Angeles National Forest.

Physiography

The Ventura and Los Angeles parts of this area are in the Los

Angeles Ranges Section of the Pacific Border Province of the

Pacific Mountain System. These parts of the MLRA consist

mainly of gently sloping to strongly sloping, dissected coastal

and alluvial plains that are bordered by steep hills. Changes in

sea level over time have changed the coastal plains into

terraces. Stream incision has created abandoned flood plains, or

terraces, adjacent to most rivers. The inland boundary of these

parts of the MLRA occurs where the sloping plains coalesce

with steeper alluvial fans and colluvial slopes coming off

inland mountain ranges. The eastern end of the Sierra Madre

Range forms the inland border in the Ventura area, and the San

Gabriel Mountains form the inland border in the Los Angeles

area. Elevation ranges from sea level to 1,970 feet (600 meters).

The southern part of this MLRA, around San Diego, is in the

Lower Californian Province of the Pacific Mountain System. In

this part of the MLRA, the coastal plain between the Pacific

Ocean and the Vallecito Mountains is narrow and colluvial

slopes from the mountains form the eastern boundary.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Southern California Coastal (1807), 99 percent, and Southern

Mojave-Salton Sea (1810), 1 percent. The Los Angeles River is

confined to a concrete-lined flood-control channel through the

city of Los Angeles. A series of debris dams near the inland

border of this MLRA traps the sand, gravel, cobbles, and

boulders that are carried by the mountain streams down to the

coastal plain. The dams not only reduce the need for dredging

in the Los Angeles River but also create a new source of sand

and gravel for construction. The Santa Clara River enters the

ocean near Ventura. This city is protected from flooding by

levees. The Santa Clara River is the primary source of sand for

the beaches of Los Angeles and other communities to the south.

Extensive gravel mining from this river has decreased the

amount of coarse material reaching the sea and has led to severe

beach erosion, which has prompted local officials to build

numerous groins and jetties intended to trap sand moving south

in littoral currents and to reduce the hazard of beach erosion.

Geology

The coastal plains in this MLRA consist of thick layers of

river-laid sediments that tend to become finer textured nearer

the ocean. Very coarse sediment is on the colluvial slopes and

alluvial fans on the inland border of the MLRA. Lower sea

levels have transformed the plains into the marine terraces of

today. Southern California is the western boundary of the North

American continental plate. The Pacific Ocean plate is being

subducted beneath the continental plate in this area. The

continental plate is moving up and northwest as the ocean plate

slides beneath it. Numerous faults occur in this MLRA, and

earthquakes are common as the plates slide past each other.

Climate

The average annual precipitation in this area is 10 to 29

inches (255 to 735 millimeters). Most of the rainfall occurs as

low- or moderate-intensity, Pacific frontal storms during winter.

At the higher elevations, rain occasionally turns to snow during

winter. Summers are dry, but fog provides some moisture along

the coast. The average annual temperature is 55 to 66 degrees F

(13 to 19 degrees C). The freeze-free period averages 310 days

and ranges from 255 to 365 days along the coast. The length of

the period decreases towards the hills.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 36.7%; ground water, 26.9%

Livestock—surface water, 0.1%; ground water, 0.0%

Irrigation—surface water, 27.1%; ground water, 7.6%

Other—surface water, 1.3%; ground water, 0.3%

The total withdrawals average 2,490 million gallons per day

(9,425 million liters per day). About 35 percent is from ground

water sources, and 65 percent is from surface water sources. The

low rainfall and intermittent streamflow provide small

quantities of surface water for local use. Much of the water for

irrigation and nearly all of the water for large urban areas is

diverted from the Colorado and Owens Rivers, in eastern

California, and from northern California rivers via aqueducts.

This imported water is typically of good quality and is suitable

for drinking after minimal treatment. The competition for water

between the populated areas and the agricultural areas has

increased the cost of water in southern California.

Desalinization is becoming economically viable as the cost of

imported surface water rises.

The limited ground water in the alluvial deposits and older

sediments under the coastal plains has been heavily exploited.

The quality of this ground water in inland areas is generally

good. It is suitable for all uses. Declining water tables and the

intrusion of saltwater are reducing both the quantity and quality

of this water. The level of total dissolved solids typically

exceeds 1,000 parts per million (milligrams per liter) near the

coast, and the level of chloride reduces the usefulness of the

water for irrigating salt-sensitive crops.
of the United States 57

Soils

The dominant soil orders in the MLRA are Alfisols, Entisols,

and Mollisols. The soils in the area dominantly have a thermic

soil temperature regime, a xeric soil moisture regime, and

mixed mineralogy. They generally are deep or very deep, well

drained or somewhat excessively drained, and loamy or sandy.

The dominant soils in the MLRA formed in alluvial sediments.

Haploxeralfs (Greenfield and Ramona series) and Haploxerolls

(Mocho series) are on alluvial fans and terraces. Haploxerolls

(Chino series), Xerofluvents (Camarillo, Hueneme, Metz, and

San Emigdio series), Xeropsamments (Corralitos and Tujunga

series), and Xerorthents (Hanford series) are on alluvial fans

and flood plains. Durixeralfs (Redding series) are on dissected

terraces. Haploxeralfs (Cajalco and Fallbrook series),

Xerorthents (Cieneba and Exchequer series), and Haploxerolls

(Friant and Hambright series) are on hills.

Biological Resources

The vegetation in this area consists primarily of annual and

perennial grasses and scattered coast live oak. Rangeland

supports wild oats, soft chess, red brome, filaree, burclover,

needlegrass, tarweed, mustard, and annual lupine interspersed

with coast live oak occurring as scattered individual trees to

dense stands. Stands of brush include buckwheat, ceanothus,

California sagebrush, chamise, and scrub oak. A unique stand of

rare Torrey pine grows in this area between Del Mar and Solana

Beach.

The major wildlife species include deer, feral hog, mountain

lion, coyote, bobcat, raccoon, skunk, jackrabbit, gray squirrel,

ground squirrel, rattlesnake, turkey vulture, roadrunner, crow,

quail, pigeon, blackbird, dove, heron, and coot.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 6%

Grassland—private, 20%; Federal, 3%

Forest—private, 4%

Urban development—private, 53%; Federal, 9%

Water—private, 1%

Other—private, 3%; Federal, 1%

Nearly two-thirds of this area consists of urban or built-up

areas, and other land in the area is rapidly being converted to

urban uses. About a third of the area is brushland used for

watershed protection. The irrigated crops are subtropical fruits,

deciduous fruits, grain, truck crops, grapes, hay, and pasture.

Dairy farming and flower seed production are other important

enterprises. Some livestock is produced on the rangeland.

The major soil resource concerns are erosion, maintenance of

the content of organic matter in the soils, water quality, and low

infiltration rates resulting from hydrophobic soil properties

created via plant chemical exudates and/or after wildfires.

The erosion hazard is slight on the soils in valleys and on

terraces and benches in the valleys, except where improper

irrigation practices are more damaging than rainfall. If the

surface is unprotected in winter, the hazard of sheet and gully

erosion is severe on the sloping soils on coastal terraces and

benches and on upland soils. Salinity and encroachment of

seawater into ground-water basins is a problem in the valleys at

sea level.

The important conservation practices on cropland and dairy

farms are irrigation water management and nutrient management.

Prescribed grazing, fencing, and water management are

important practices on rangeland and other grazing land. 

Figure 20-1: Location of MLRA 20 in Land Resource Region C.

20—Southern California Mountains

This area is entirely in California (fig. 20-1). It makes up

about 9,605 square miles (24,890 square kilometers). The towns

of Santa Barbara, Fillmore, Ramona, and Banning, California,
58 Major Land Resource Areas

are in this MLRA. A major portion of the MLRA is made up of

national forests, including Los Padres, San Rafael, Angeles,

Cleveland, and San Bernardino National Forests. The area has

numerous Indian reservations. Interstate 5 crosses the center of

the northern half of the area, and Interstate 15 crosses the

eastern end of the northern half.

Physiography

The northern half of this area is in the Los Angeles Ranges

Section of the Pacific Border Province of the Pacific Mountain

System. The northwestern end of the MLRA is in the California

Coast Ranges Section of the same province and system. The

mountains in this area are called the Transverse Ranges since

their trend is almost east and west, almost perpendicular to all

other mountain ranges in California. In the northwestern end of

the area, the Transverse Ranges merge with the Coast Range.

The southern half of this MLRA is called the Peninsular Range

and is in the Lower Californian Province of the Pacific

Mountain System. The Sierra Madre, San Gabriel, San

Bernardino, Santa Rosa, and Vallecitos Mountains occur in this

area, from north to south. The eight Channel Islands also occur

in this area.

This MLRA is an area of narrow mountain ranges and broad

fault blocks. Elevation ranges from 1,000 to 7,900 feet (305 to

2,400 meters) in most of the area. The highest peaks can exceed

12,000 feet (3,660 meters). A narrow strip along the northern

edge of the area is almost at sea level. The strongly sloping to

precipitous mountains have unstable slopes and sharp crests.

Valleys are typically narrow and are filled with alluvium.

Almost all of the valleys have streams with actively eroding

banks. The valley floors for Calleguas Creek and the Santa

Clara River are wide, and colluvial slopes and alluvial fans

have formed at the edges of these valleys.

The extent of the major Hydrologic Unit Areas (identified

by four-digit numbers) that make up this MLRA is as follows:

Southern California Coastal (1807), 71 percent; Central

California Coastal (1806), 14 percent; Southern Mojave-Salton

Sea (1810), 8 percent; Northern Mojave-Mono Lake (1809), 5

percent; and Tulare-Buena Vista Lakes (1803), 2 percent. The

Santa Clara River, the chief source of sand for the beaches to

the south, originates in this area. The headwaters of the Los

Angeles River also are in this area.

Geology

The mountains in the Transverse Ranges primarily consist of

uplifted and tilted Cenozoic marine sediments. The far eastern

end of this range consists of Precambrian rocks and Mesozoic

volcanics. The Peninsular Range is primarily granite. Mesozoic

sediments that have been metamorphosed occur at the margins

of the granitic intrusives. The valleys are filled with relatively

coarse alluvium since most of the sediments have not moved far

from their source.

The Transverse Ranges are very young from a geological

perspective and are bounded by the San Andreas Fault. This

fault occurs where the North American continental plate is

sliding over the Pacific Ocean plate. Earthquakes are common

as the two plates slip past each other. Landslides also are a

major land-forming process in this MLRA. These frequently

occur during rainstorms in winter, when the soils become

saturated, and following brush fires after the root systems of the

brush decay.

Climate

The average annual precipitation in this area is 8 to 51 inches

(205 to 1,295 millimeters), increasing with elevation. Most of

the rainfall occurs as low- or moderate-intensity, Pacific frontal

storms during winter. Rain can turn to snow at the higher

elevations. A little snow may fall in winter, but it does not last.

Summers are dry. The average annual temperature is 41 to 66

degrees F (5 to 19 degrees C), decreasing with elevation. The

freeze-free period averages 245 days and ranges from 125 to

365 days in most of the area. It decreases in length with

elevation. The longest freeze-free period occurs at the lower

elevations along the western edge of the area.

The climate on the eight Channel Islands can differ

somewhat from the climate on the mainland portions of this

MLRA. The southern Channel Islands tend to be warmer and

drier than their northern counterparts because the California

Current (ocean current) is warmer when it reaches the southern

islands. Santa Catalina Island has an average annual

precipitation of 12 inches (305 millimeters measured for over

30 years at Avalon) and an average annual summer temperature

of 59 to 74 degrees F (15 to 23 degrees C). The average annual

winter temperature, recorded at Avalon, ranges from 49 to 63

degrees F (9 to 17 degrees C). The northern islands have a

climate that tends to be moderated by fog. They have slightly

higher humidity and lower cloud cover than the adjacent

coastal mainlands. These northern islands, especially Santa

Cruz and Santa Rosa, receive consistent and regular winds

prevailing from the northwest. These winds may have higher

velocity than the mainland winds.

Water

Following are the estimated withdrawals of freshwater by use

on the mainland portions of this MLRA:

Public supply—surface water, 25.4%; ground water, 45.8%

Livestock—surface water, 0.4%; ground water, 0.2%

Irrigation—surface water, 11.4%; ground water, 12.7%

Other—surface water, 2.1%; ground water, 2.0%

The total withdrawals average 395 million gallons per day

(1,495 million liters per day). About 61 percent is from ground

water sources, and 39 percent is from surface water sources. The

moderate rainfall provides water for brushland and range and
of the United States 59

also meets part of the water needs of the adjacent lower areas.

Runoff is rapid. All but the larger streams and those that drain

from the higher watersheds are dry through the summer and in

periods of low precipitation. There are very few manmade or

natural lakes in the area. Most of the public water supplies are

obtained from surface water diverted from northern California

rivers. This water is of good quality and is suitable for drinking

after minimal treatment.

Deep sand and gravel deposits in the valleys yield water for

livestock and domestic use and for some irrigation. The median

level of total dissolved solids in this ground water is near the

national drinking water standard of 500 parts per million

(milligrams per liter).

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, Inceptisols, and Mollisols. The soils in the area

dominantly have a mesic or thermic soil temperature regime, a

xeric soil moisture regime, and mixed mineralogy. They

generally are very shallow to deep, well drained or somewhat

excessively drained, and loamy or sandy. The dominant soils

formed in residuum. Very shallow and shallow Xerorthents

(Cieneba and Exchequer series) are on uplands, and deep

Xerorthents (Saugus series) are on terraces and foothills.

Shallow Haploxerolls (Friant, Sheephead, and Tollhouse series),

deep (Crouch series) and moderately deep (La Posta series)

Haploxerolls, and moderately deep Rhodoxeralfs (Las Posas

series) are on mountain slopes. Deep Haploxeralfs (Fallbrook

series) are on hills. Moderately deep Haploxerepts (Vista series)

are on hills and mountain slopes.

Biological Resources

This area supports forest, brush, and shrub-grass mixtures.

Open stands of Jeffrey pine, Coulter pine, sugar pine, Douglasfir, incense-cedar, and oak are at elevations above 4,000 feet

(1,220 meters). At elevations above 8,000 feet (2,440 meters),

subalpine conifer forests occur. They consist of lodgepole

pine, limber pine, white fir, and western juniper. The greater

part of the area is covered with sparse to dense stands of brush.

Scrub oak, juniper, chamise, ceanothus, manzanita, and red

shank are typical species. The rangeland soils support

naturalized annual and native perennial grasses and brush.

California juniper, big sagebrush, flattop buckwheat,

needlegrass, wild oats, soft chess, cheatgrass, and filaree

characterize the plant cover on the coarse textured soils. Oaks,

Jeffrey pine, and an understory of soft chess, wild oats,

needlegrass, blue wildrye, ceanothus, flattop buckwheat, and

other brush species grow on the medium textured soils.

Creeping wildrye, pine bluegrass, sedges, and native clovers are

the major species in the wet meadows.

The vegetative communities on the Channel Islands include

native island endemics, such as island hazardia, island

malacothrix, cliff malacothrix, live-forever, island manzanita,

island scrub oak, island oak, Channel Island tree poppy, island

poppy, island buckwheat, island ceanothus, island redberry,

island ironwood, and island monkeyflower. Nonendemics play

a significant role in the diverse plant life of the islands. These

are California sagebrush, lemonade berry, toyon, coyotebrush,

needlegrasses, canyon live oak, and Bishop pine.

Some of the major wildlife species in this MLRA include

deer, feral hog, mountain lion, bighorn sheep, coyote, bobcat,

raccoon, skunk, jackrabbit, gray squirrel, ground squirrel,

rattlesnake, California condor, turkey vulture, roadrunner, crow,

quail, pigeon, blackbird, dove, heron, and coot. Species of

concern include cactus wren, California gnatcatcher, Bell’s

vireo, mountain yellow and red-legged frogs, arroyo toad, and

southwestern willow flycatcher.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 3%

Grassland—private, 29%; Federal, 36%

Forest—private, 5%; Federal, 10%

Urban development—private, 6%

Water—private, 1%

Other—private, 9%; Federal, 1%

Less than one-tenth of this area is used for urban

development, and the rest is in farms, ranches, or other private

holdings. Less than one-fifth of the area is open woodland and

brushland used for grazing. More than half of the area has a

brush cover that is not grazed. Most of the larger valleys are

used for dry-farmed grain and hay, but in some areas fruits are

grown under irrigation.

The major soil resource concern is a severe erosion hazard in

areas where the plant cover is depleted or destroyed by

overgrazing or fire. Preventing or controlling brush fires is a

major concern.

The important conservation practices are prescribed grazing,

fencing, and water management on rangeland and other grazing

land; erosion control, irrigation water management, and

nutrient management on urban land; erosion control, irrigation

water management, and nutrient management on cropland,

including orchards; and thinning and control of competing

vegetation on forestland. 

61

Figure D-1: Location of Land Resource Region D.

D—Western Range and Irrigated Region

This region (shown in fig. D-1) is in Arizona (21 percent),

Nevada (20 percent), California (14 percent), New Mexico (13

percent), Utah (11 percent), Wyoming (7 percent), Texas (5

percent), Oregon (4 percent), Colorado (3 percent), Idaho (2

percent), and Montana (less than 1 percent). It makes up

549,725 square miles (1,424,480 square kilometers). This is the

largest of all the land resource regions in land area.

This is a semidesert or desert region of plateaus, plains,

basins, and many isolated mountain ranges (fig. D-2). The

average annual precipitation ranges from 6 inches (150

millimeters) on some of the plains and in some basins to 42

inches (1,065 millimeters) on some of the higher mountains. In

the southeast part of the region, most of the precipitation falls as

rain during the warm season. Elsewhere in the region, however,

most of the precipitation falls during the cool season. In most of

this region, the average annual temperature is 40 to 60 degrees

F (4 to 16 degrees C). The freeze-free period ranges from 105

days in the north and in some of the higher mountains to 260

days in the south.

The total withdrawals of freshwater in this region average

about 30,025 million gallons per day (113,645 million liters

per day). About 76 percent is from surface water sources, and 24

percent is from ground water sources. About 86 percent of the

water is used for irrigation. Because of its large area, this is one

of six land resource regions that use more than 30,000 million

gallons (113,550 million liters) of water daily.

The soils in this region are dominantly Aridisols, Entisols,

and Mollisols. The dominant suborders are Argids and Calcids

on plains and in basins; Orthents on plains, on plateaus, and in

valleys throughout the region; and Xerolls and Ustolls on

mountain slopes. The soils in the region dominantly have a

mesic soil temperature regime, an aridic soil moisture regime,

and mixed mineralogy.

About 60 percent of the land in this region is federally

owned. The native vegetation consists mainly of shrubs with

interspersed grasses and scattered trees. Much of the land in the
62 Major Land Resource Areas

Figure D-2: An area of Land Resource Region D.

region is used for grazing. Irrigated crops are grown in areas

where water is available and the soils are suitable. Feed crops

for livestock are grown on much of the irrigated land. Peas,

beans, and sugar beets are grown in many areas. Cotton and

citrus fruits are important crops in southwestern Arizona. The

major resource management concerns on cropland include soil

productivity and the content of salts and sodium in the soils.

Overgrazing is a concern on rangeland. 
of the United States 63

Figure 21-1: Location of MLRA 21 in Land Resource Region D.

21—Klamath and Shasta Valleys and

Basins

This area (shown in fig. 21-1) is in California (65 percent)

and Oregon (35 percent). It makes up about 11,495 square miles

(29,790 square kilometers). The towns of Alturas, Adin, Canby,

Yreka, and Fall River Mills, California, and Klamath Falls,

Lakeview, Malin, and Merrill, Oregon, are in this MLRA. U.S.

Highways 97 and 385 cross the west and east parts of this area,

respectively. Numerous national forests are in the MLRA,

including the Klamath, Modoc, Fremont, Lassen, Plumas, and

Shasta National Forests.

Physiography

This area is in a transition zone between the Basin and

Range Province to the southeast, the Cascade and Klamath

Mountains to the west and northwest, and the Sierra Nevada

Mountains to the south. Most of this MLRA is in the Great

Basin Section of the Basin and Range Province of the

Intermontane Plateaus. Small areas in the west and northwest

parts of the MLRA are in the Middle Cascade Mountains

Section of the Cascade-Sierra Province of the Pacific Mountain

System. The Shasta River Valley portion of this MLRA, near

Yreka, is along the western edge of the Cascade Range, near the

Klamath Mountains, while the Scott River Valley portion is

farther west within the Klamath Mountains. The Modoc portion

of the MLRA is characterized by a vast volcanic upland

interspersed with numerous reservoirs, lakes, and narrow stream

valleys that comprise the Pit and Klamath River drainages;

hydrologically separate, internally drained basins with lakes or

periodically dry lakebeds; and isolated volcanic peaks.

Elevation typically ranges from 2,600 to 4,600 feet (795 to

1,400 meters), but many mountain peaks exceed 7,000 feet

(2,135 meters) and a few peaks in Oregon exceed 8,000 feet

(2,440 meters). Lava plateaus and many valleys and basins

make up most of the area. Steep mountain spurs and rimrock

escarpments surround the plateaus.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Klamath-Northern California Coastal (1801), 47 percent;

Sacramento (1802), 36 percent; North Lahontan (1808), 11

percent; and Oregon Closed Basins (1712), 6 percent. The

Klamath River originates in this area.

Geology

The Modoc portion of this MLRA is underlain by Cenozoic

volcanic rocks. Surface exposures are dominated by Miocene to

Pleistocene “flood basalts” and rhyolite ash. Andesites,

volcanic mudflow deposits, and rhyolitic intrusives also occur.

Volcanism and the extrusion of flood basalts occurred as a result

of crustal thinning and extension associated with development

of the Basin and Range. Valleys are typically underlain by

recent alluvial, lacustrine, and dry lakebed (playa) deposits.

Pliocene to Pleistocene nonmarine sedimentary deposits

(including fan and stream terrace deposits and old lake deposits)

underlie portions of many of the basins.

The geology of the Shasta River Valley portion of this

MLRA is complex, reflecting its location between the Klamath

Mountains and the High Cascades. Uplands in the northern and

western parts of the area are underlain by pre-Cenozoic

metamorphics and sedimentary formations, while the eastern

portion is dominated by Tertiary and Quaternary volcanics.

The Scott River Valley portion of this MLRA is underlain by

alluvium and alluvial terrace deposits derived from the nearby

Klamath Mountains, which are locally composed of preCenozoic metamorphic, granitic, and ultramafic rocks.

Climate

The average annual precipitation is 12 to 30 inches (305 to

760 millimeters) in most of this area. The drier areas can receive

as little as 9 inches (230 millimeters). In small areas at high

elevations on the western and southwestern edges of this

MLRA, the average annual precipitation is much higher, 30 to

58 inches (760 to 1,475 millimeters). Higher precipitation

zones also occur in the scattered mountain ranges throughout

the rest of this area. Most of the rainfall occurs as low- or

moderate-intensity, Pacific frontal storms during the winter. At

the higher elevations, rain generally turns to snow. Snow may
64 Major Land Resource Areas

fall at the lower elevations in winter but does not last. Summers

are dry. The average annual temperature is 39 to 52 degrees F

(4 to 11 degrees C). The freeze-free period averages 130 days

and ranges from 70 to 185 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 0.7%; ground water, 0.9%

Irrigation—surface water, 70.1%; ground water, 24.2%

Other—surface water, 2.3%; ground water, 1.9%

The total withdrawals average 1,470 million gallons per day

(5,565 million liters per day). About 27 percent is from ground

water sources, and 73 percent is from surface water sources. The

somewhat limited precipitation and the lack of sufficient water

storage limits the supply of water for agriculture. In the

narrower valleys, the irrigated land is in areas on alluvial fans

where surface runoff from the mountains can be diverted to

fields. Some terraces along the major drainages also are

irrigated. The surface water is of excellent quality and is

suitable for drinking.

Ground water is scarce in the dense lava rocks underlying

much of the area. On sites underlain by the more porous rocks,

the supplies of ground water are large but are mostly untapped.

Some irrigation water is obtained from fracture and rubble

zones and layers of sand and gravel within the lava. Also,

some is obtained from the basin fill aquifers between the

mountain ranges. Little information about the quality of the

ground water is available, except that the water is suitable for

irrigation.

Soils

The dominant soil order in this MLRA is Mollisols. Small

areas of Inceptisols and Histosols are in the basins. The soils in

this area dominantly have a mesic or frigid soil temperature

regime, a xeric soil moisture regime, and mixed or smectitic

mineralogy. They generally are well drained, but they may be

poorly drained or very poorly drained in the basins. They

generally are loamy, clayey, or sandy and are shallow to very

deep. Argixerolls formed in residuum (Lorella and Orhood

series) and in residuum mixed with loess and/or volcanic ash

(Devada, Royst, and Woodcock series) on plateaus, hills, and

mountains. Haploxerolls (Fordney series) formed in sandy

alluvium on terraces. Haploxerolls (Petescreek series) formed in

residuum on hills and mountains. Palexerolls (Booth series)

formed in colluvium on plateaus, hills, and mountains.

Durixerolls (Salisbury series) formed in old alluvium on

terraces. Humaquepts (Tulana series) formed in lacustrine

sediments on lacustrine bottoms. Haplohemists (Lather series)

formed in organic material in marshes.

Biological Resources

This area has a cover of shrubs interspersed with annual and

perennial grasses. Nevada bluegrass, Sandberg bluegrass, Idaho

fescue, and bluebunch wheatgrass are the major species. The

basins and meadows support sedges, wiregrass, slender

wheatgrass, creeping wildrye, and bluegrass. Sagebrush,

rabbitbrush, bitterbrush, and mountain mahogany are the main

shrubs. Western juniper is common, and scattered ponderosa

pine trees are on the lower foothills. The higher elevations

support ponderosa pine, Douglas-fir, white fir, and California

red fir with an understory of bitterbrush and ceanothus.

Some of the major wildlife species in this area are elk, mule

deer, antelope, golden eagle, red-tailed hawk, prairie falcon,

great horned owl, barn owl, sage grouse, and chukar.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 5%

Grassland—private, 21%; Federal, 20%

Forest—private, 17%; Federal, 24%

Urban development—private, 1%

Water—private, 5%; Federal, 6%

Other—private, 1%

Most of the privately and publicly owned land in this area is

grazed. A small acreage is used for irrigated potatoes, grain,

seed crops, hay, or pasture or for dry-farmed grain. Trees are

harvested for lumber in some forested areas.

The major soil resource concerns on cropland are wind

erosion, water erosion, maintenance of the content of organic

matter and productivity of the soils, conservation of soil

moisture, and the quality of irrigation water. The hazard of

water erosion is slight in most of the basin areas but can be high

in the steeper areas if the surface is bare. In some areas the

hazard of wind erosion is high, especially when the surface is

disturbed during the period of highest wind velocities.

Maintaining good drainage is the principal management

concern in the valley basins. Some sites should be protected

from overflow, and others are affected by alkali. Overgrazing

and the invasion of undesirable species are management

concerns on rangeland. Surface compaction and sedimentation

of streams are the major management concerns on forestland.

Conservation practices on cropland generally include

irrigation water management, water-control structures, irrigation

system improvements, and nutrient management. Conservation

practices on rangeland and pasture generally include prescribed

grazing, water developments, and brush management.

Conservation practices on forestland generally include forest

site preparation, forest stand improvement, and forest trails and

landings. These practices help to control compaction, the

erosion caused by concentrated flow, and sediment delivery to

streams. 
of the United States 65

Figure 22A-1: Location of MLRA 22A in Land Resource Region D.

22A—Sierra Nevada Mountains

This area (shown in fig. 22A-1) is in California (98 percent)

and Nevada (2 percent). It makes up about 18,810 square miles

(48,745 square kilometers). It has a few large communities.

Quincy, South Lake Tahoe, and Truckee, California, are in this

MLRA. The smaller communities include Markleeville, Colfax,

and Kernville. Interstate 80 crosses the center of this area.

Yosemite and Sequoia-Kings Canyon National Parks occur in

the area. A major portion of this MLRA is in national forests,

including the Eldorado, Inyo, Plumas, Sierra, Sequoia,

Stanislaus, and Tahoe National Forests. Numerous Indian

reservations are in the MLRA, including the Berry Creek

Rancheria, Enterprise Rancheria, Greenville Rancheria, Jackson

Rancheria, Sheep Ranch Rancheria, and Tuolumne Rancheria

Reservations.

Physiography

This MLRA lies entirely within the Sierra Nevada Section of

the Cascade-Sierra Mountain Province of the Pacific Mountain

System. This area consists of the higher elevations of the Sierra

Nevada Mountains. It is a strongly asymmetric mountain range

with a long, gentle western slope and a steep eastern

escarpment. It is characterized by hilly to steep mountain relief

and occasional mountain valleys. It is 50 to 80 miles (80 to 130

kilometers) wide and runs in an approximately north-south

direction through eastern and central California for more than

400 miles (645 kilometers).

Elevation ranges from 1,500 to 9,000 feet (455 to 2,745

meters) in most of the area. The highest peaks can exceed

12,000 feet (3,660 meters). Mount Whitney, at an elevation of

14,494 feet (4,419 meters), is the highest point in the lower 48

States. The strongly sloping to precipitous mountains have

unstable slopes and sharp crests. Valleys are typically narrow

and are filled with alluvium. Almost all of the valleys have

streams with actively eroding banks.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Sacramento (1802), 31 percent; San Joaquin (1804), 31 percent;

Tulare-Buena Vista Lakes (1803), 20 percent; Central Lahontan

(1605), 10 percent; Northern Mojave-Mono Lake (1809), 7

percent; and North Lahontan (1808), 1 percent. The American,

Carson, Kern, San Joaquin, Truckee, Walker, and Yuba Rivers

originate in this area.

Geology

Most of this area is dominated by plutonic (dominantly

quartz monzonite and granodiorite) rocks of Mesozoic age,

otherwise known as the Sierra Nevada Batholith. The north half

of the range is flanked on the west by the western metamorphic

belt, an area of strongly deformed and metamorphosed

sedimentary and volcanic rocks of Paleozoic and Mesozoic

age. Farther south, some of these metamorphic rocks are within

the batholith on the western edge or along the crest of the

range. Volcanic activity of minor extent has produced Mioceneage lava flows. The valleys are filled with relatively coarse

alluvium since most of the sediments have not moved far from

their source.

Gold occurs as lode deposits in Mesozoic metamorphic

rocks of the western foothills, where heat generated from the

intrusion of the Sierra Nevada Batholith mobilized and

concentrated the gold in quartz veins. The most productive

districts are in the “Mother Lode” belt in the northern and

central parts of the Sierra Nevada Mountains. Placer deposits of

gold, which accounted for more than 40 percent of California’s

total gold output, are in Tertiary stream gravel in the

northwestern part of the Sierra Nevada Mountains and in recent

stream channels where gold-bearing rocks eroded from areas

near the Sierran crest are transported towards the valleys of the

Sacramento and San Joaquin Rivers.

Pleistocene to Recent glaciers have shaped the Sierra

Nevada Mountains by scouring out cirques, U-shaped

valleys, and other glacial erosional features, depositing

poorly sorted till in glacial moraines and influencing

streamflow patterns by contributing variable amounts of

runoff and periodically forming ice dams and lakes. The

intermontane valleys are filled with coarse glacial deposits
66 Major Land Resource Areas

and with coarse alluvium since most of the deposits have not

moved far from their source.

Climate

The average annual precipitation is 40 to 80 inches (1,015

to 2,030 millimeters) in much of this area, but it as low as 6

inches (150 millimeters) in the lower valleys and foothills and

as much as 100 inches (2,540 millimeters) on the mountain

peaks. The amount of precipitation increases with elevation

and from south to north. Summers are dry, but there are

occasional thunderstorms. Much of the winter precipitation

occurs as snow. The average annual temperature is 25 to 63

degrees F (-4 to 17 degrees C), decreasing with elevation. The

freeze-free period averages 205 days and ranges from 65 to 345

days, decreasing in length with elevation. It is longest at the

lower elevations along the western edge of the area.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 41.8%; ground water, 0.0%

Livestock—surface water, 25.5%; ground water, 0.9%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 24.9%; ground water, 6.9%

The total withdrawals average 2 million gallons per day (8

million liters per day). About 8 percent is from ground water

sources, and 92 percent is from surface water sources. The

abundant rainfall and snowfields on the higher mountain slopes

provide water for forestland and rangeland. Also, they meet part

of the water needs of the lower adjacent areas by supplying

water to many perennial rivers. Much of the water is stored in

large reservoirs and is used in the valleys of the Sacramento and

San Joaquin Rivers and in heavily populated southern

California. Most of the public water supplies are obtained from

surface water. This water is of good quality and is suitable for

drinking after minimal treatment. The mountains provide

opportunities for recreation to many people in California and to

visitors from other States. There have been problems with fecal

coliform and Giardia contamination in the surface water at high

elevations.

There are no principal aquifers in the Sierra Nevada

Mountains. Some ground water is obtained from alluvium on

valley floors. The fractures and joints in bedrock are the only

other sources of ground water. The ground water is suitable for

almost all uses, but it is little used in this area.

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, Inceptisols, Mollisols, and Ultisols. The soils in the

area dominantly have a mesic, frigid, or cryic soil temperature

regime, depending largely on elevation; a xeric soil moisture

regime; and mixed mineralogy. They generally are very shallow

to deep, well drained or somewhat excessively drained, and

loamy or sandy. The dominant soils in the MLRA formed in

residuum and colluvium on hills and mountains.

The soils at elevations below 3,900 to 4,900 feet (1,190 to

1,495 meters) include deep or very deep Haplohumults (Sites

and Aiken series), Haploxeralfs (Secca, Holland, and Cohasset

series), Haploxerults (Josephine series), and moderately deep

Haploxerults (Mariposa series), all of which formed in material

weathered from metavolcanic and metasedimentary rocks. Deep

and very deep Dystroxerepts (Chaix and Shaver series) formed

in material weathered from granodiorite.

At the higher elevations, deep and very deep Haploxeralfs

(Holland and Musick series), Xeropsamments (Cagwin,

Corbett, and Toiyabe series), and Dystroxerepts (Meeks series)

formed in material weathered from granodiorite and

Dystroxerepts (Umpa series), Haploxerands (Meiss series), and

Vitrixerands (Waca and Windy series) formed in material

weathered from andesite. Large areas of rock outcrop are

throughout the MLRA. They are on broad expanses on ridge

crests and peaks above timberline, at an elevation of 7,875 to

8,850 feet (2,400 to 2,700 meters).

The soils in mountain valleys formed in mixed alluvium.

They include Dystroxerepts (Gefo and Jabu series), Argicryolls

(Macareeno series), and Haploxeralfs (Inville series).

Biological Resources

This area supports montane coniferous forest vegetation.

The main species are ponderosa pine, Douglas-fir, incense

cedar, sugar pine, white fir, California red fir, Jeffrey pine,

lodgepole pine, and mountain hemlock. Bristlecone pine grows

in protected draws at elevations above 8,850 feet (2,700

meters). Bluegrass, hairgrass, sedges, wiregrass, clovers, and

wild iris grow in montane meadows. Manzanita, sagebrush,

blue wildrye, fescues, bluegrasses, and mountain brome are

common understory species in open stands of timber.

Some of the major wildlife species in this area are blacktailed deer, mountain lion, bighorn sheep, coyote, bobcat, gray

fox, raccoon, skunk, jackrabbit, gray squirrel, rattlesnake,

California condor, turkey vulture, roadrunner, crow, quail, bandtailed pigeon, and blackbird. The species of fish in the area

include rainbow, brown, brook, cutthroat, and golden trout,

anadromous salmonids, and northern pike minnow.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—private, 2%; Federal, 5%

Forest—private, 18%; Federal, 65%

Urban development—private, 2%

Water—private, 2%; Federal, 5%

Other—private, 1%
of the United States 67

About three-fourths of this area is federally owned land,

which is primarily in national forests and parks. The rest of the

area is privately owned forestland, farms, and ranches. About 83

percent of the area is forestland used for timber, recreation,

wildlife habitat, and watershed. Approximately 7 percent is

pasture or range. The area has very little cropland. The cropland

is used mainly for deciduous fruits, grain, or hay. Livestock

grazing is confined to mountain meadows, which

are grazed during summer, and to areas with open stands of

timber.

The major resource management concerns on upland soils at

intermediate elevations are low pH (moderate or strong acidity)

and fertility. The uplands are hilly to mountainous and are

subject to erosion in areas where the soils are disturbed by

logging, fires, overgrazing, or cultivation. The hazard of

erosion is highest on the moderately coarse textured, granitic

soils. In areas of shallow soils, soil depth and a low available

water capacity are limitations.

The upland soils at high elevations have severe climatic

limitations. They also have low pH (moderate or strong acidity)

and fertility. Erosion is a hazard in areas on these highelevation, mountainous slopes where the soils are disturbed by

fires and logging operations. Most of the soils are stony and

have a low available water capacity.

In the mountain valleys, water management is needed to

prevent stream downcutting and gullying and to maintain a

satisfactory moisture condition for the growth of desirable plant

species. Drainage can be a problem in many of the soils.

Preventing or controlling wild-land fires is a major

management concern. Older or improperly designed roads

contribute sediment to streams. Other management concerns

include compaction resulting from farming activities, the

impacts of catastrophic wildfire on forestland, and maintenance

of the content of organic matter in the soils.

Conservation practices on all kinds of land in this MLRA

include measures that control erosion on access roads and

measures that protect riparian areas. The most important

conservation practices on forestland are those that improve

forest health, reduce the chance of catastrophic wildfire, and

protect wildlife habitat. These practices include tree and shrub

establishment, forest stand improvement, forest harvest trails

and landings, critical area planting, and reduction of the extent

of understory fuels.

Conservation practices on cropland and pasture generally

include irrigation water management, water-control structures,

protection of riparian areas, control of streambank erosion, and

nutrient and pesticide management. Prescribed grazing, fences,

and water management are the most important practices on

rangeland and other grazing land.

 Conservation practices in rapidly expanding areas used for

urban development generally include properly designing roads,

improving forest health, and reducing the chance of

catastrophic wildfire and thus protecting wildlife habitat. 

Figure 22B-1: Location of MLRA 22B in Land Resource Region D.

22B—Southern Cascade Mountains

This area (shown in fig. 22B-1) is entirely in California. It

makes up about 5,855 square miles (15,175 square kilometers).

The most prominent town in this MLRA is Burney. U.S.

Highway 97 crosses the western part of the area. Lassen

Volcanic National Park occurs in the area. A major portion of

this MLRA is in national forests, including the Lassen and

Klamath National Forests and portions of the Shasta-Trinity

National Forest. The area has several Indian reservations,

including the Big Bend Rancheria, Montgomery Creek

Rancheria, and Roaring Creek Rancheria Reservations.

Physiography

The area lies within the southern end of the Middle Cascade

Mountains Section of the Cascade-Sierra Mountains Province

of the Pacific Mountain System. A small area in the southeast

part of the MLRA is in the Great Basin Section of the Basin and

Range Province of the Intermontane Plateaus. This MLRA is

the southernmost extent of the Cascade Mountain Range

trending north-south. It lies east of the Trinity Mountains and

the Northern Sacramento Valley and west of the Modoc Plateau

and the Great Basin and is bordered on the north by Butte

Valley and the Central Cascade Mountains. It extends to the

Sierra Nevada Mountains to the south.
68 Major Land Resource Areas

Elevation generally ranges from a low in the foothills of

about 1,500 feet (455 meters) to 8,200 feet (2,500 meters). It is

as high as 14,162 feet (4,318 meters) on Mount Shasta. This

MLRA consists mostly of rolling volcanic mountains and

intermontane basins.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this area is as follows:

Sacramento (1802), 78 percent; Klamath-Northern California

Coastal (1801), 13 percent; and North Lahontan (1808), 9

percent. The McCloud and Sacramento Rivers originate in this

area, and the Pit River flows through the area from east to west.

Geology

The Southern Cascade Mountains are made up primarily of

Tertiary and Quaternary volcanics (basalt, andesite, dacite, and

rhyolite) exposed as prominent peaks and volcanic uplands,

surrounded by lower, moderately steep and steep shield and

composite volcanoes and cinder cones. Prominent peaks and

recently active volcanic areas in this portion of the Southern

Cascades include the Medicine Lake Highlands and Medicine

Lake Volcano (located on the border with the Modoc Plateau

and characterized by silicic to basaltic eruptions as recently as

200 to 300 years ago); Mount Lassen (composed of andesite

and dacite with some glacial deposits), which most recently

erupted from 1914 to 1921; and Mount Shasta. Mount Shasta is

an active stratovolcano with two eruptive centers that have

produced pyroclastic flows, andesitic lava flows, and debris

flows. Active glaciers and associated deposits extend

downslope from the summit of Mount Shasta.

Paleozoic to Mesozoic metamorphics, sedimentary

formations, and volcanics, flanked on the east by a thin band

and stringers of Eocene sandstones, shales, and conglomerates,

are exposed in the west-central portion of the MLRA, in a band

that extends southward from the Siskiyou County line to the

uplands east of Shasta Lake. Quaternary alluvial, fluvial, and

lacustrine deposits have accumulated in small depressions on

lava flows, in larger depressions between lava flows, and in

stream valleys and basins.

Climate

The average annual precipitation in this MLRA typically is

15 to 80 inches (380 to 2,030 millimeters). It is as high as 125

inches (3,175 millimeters). The precipitation falls mainly from

fall to spring, mostly as snow. Winter precipitation is from

Pacific storms that are frontal in nature. The amount of

precipitation decreases from west to east. Summers are typically

warm and dry, but there are occasional thunderstorms. The

average annual temperature is 33 to 62 degrees F (1 to 17

degrees C). The freeze-free period averages 215 days and ranges

from 85 to 350 days. The lowest annual temperatures and the

shortest freeze-free periods occur in the mountains.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 1.7%; ground water, 0.8%

Irrigation—surface water, 90.3%; ground water, 2.3%

Other—surface water, 4.5%; ground water, 0.5%

The total withdrawals average 220 million gallons per day

(835 million liters per day). About 4 percent is from ground

water sources, and 96 percent is from surface water sources. The

abundant rainfall and snowfields on the higher mountain slopes

provide water for forestland and rangeland. Also, they meet part

of the water needs of the lower adjacent areas by supplying

water to perennial streams. The major amounts of snow during

wet, cold storms in winter provide considerable runoff for the

summer water supply. The surface water is of high quality and

has few impurities.

Ground water is in fractures, in rubble zones, and in sand

and gravel layers interbedded in the lava flows. Some also is in

the alluvial fill in the valleys. The use of ground water is

minimal in this MLRA. Recharge to the aquifers exceeds

withdrawals.

Soils

The dominant soils in this area are Alfisols, Andisols,

Entisols, Inceptisols, and Mollisols. The soil temperature

regimes are mostly mesic in the foothills and frigid in the

mountains. They are cryic at the highest elevations. The soils

on uplands are mostly well drained and have a xeric soil

moisture regime, and the soils in basins are somewhat poorly

drained or poorly drained and have a xeric to aquic soil

moisture regime. The soils on volcanic flows and mountains are

mostly Haploxeralfs (Cohasset, Eaglelake, and Lyonsville

series), Palexeralfs (Jimmerson series), Vitrixerands (Jiggs,

Neer, Ponto, Scarface, and Windy series), Haploxerands

(McCarthy series), Xerorthents (Avis series), Dystroxerepts

(Iller, Inskip, and Nanny series), and Argixerolls (Chirpchatter

and Pinehurst series). The soils in intermountain valleys and

basins include very deep Endoaqualfs (Gardens series),

Xerorthents (Orset series), Humaquepts (Chummy series),

Endoaquolls (Esro series), Epiaquolls (Swanberger series), and

Haploxerolls (Jacksback series).

Biological Resources

This MLRA has three main vegetation types—low-elevation

mixed conifer (ponderosa pine) forest, mixed conifer forest, and

upper montane red fir forest. The oak grasslands of the foothills

on the western slopes grade into a mixed conifer forest in which

ponderosa pine is the dominant species and incense cedar and
of the United States 69

California black oak are important associated species.

Important understory plants include sticky whiteleaf

manzanita, whiteleaf manzanita, and poison oak. At the higher

elevations on the western slopes, the mixed conifer forest

consists of white fir, sugar pine, ponderosa pine, incense cedar,

Douglas-fir, California black oak, and Oregon white oak. The

understory species include snowbrush ceanothus, bitter cherry,

sharpleaf snowberry, and Sierra gooseberry. The upper montane

forest communities at the higher elevations consist dominantly

of red fir and lodgepole pine. The communities on the eastern

slopes are dominated by Jeffrey pine and ponderosa pine with

an understory of antelope bitterbrush, big sagebrush, and

greenleaf manzanita. Three types of meadows are throughout

areas of these forest types. Wet meadows consist mainly of

perennial sedges, rushes, and grasses. Woodland meadows

consist mainly of scattered grasses and forbs interspersed with

lodgepole pine, willows, quaking aspen, and black

cottonwood. The shorthair sedge type occurs on the drier

meadow sites. It consists mainly of shorthair sedge, Brewer’s

lupine, western needlegrass, and spike trisetum.

Some of the major wildlife species in this area include

black-tailed deer, mule deer, mountain lion, coyote, bobcat,

yellow-bellied marmot, marten, fisher, Sierra Nevada red fox,

wolverine, and porcupine. Birds include eagles, hawks, owls,

woodpeckers, falcons, osprey, quail, northern goshawk, and

blue grouse. Species of concern include the California and

northern spotted owl. The species of fish in the area include

rainbow, brown, brook, and redband trout, anadromous

salmonids, and northern pike minnow.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 2%

Grassland—private, 8%; Federal, 9%

Forest—private, 33%; Federal, 39%

Urban development—private, 2%

Water—private, 1%; Federal, 3%

Other—private, 1%; Federal, 2%

More than half of the area is federally owned land, primarily

in national forests. The rest is privately owned forestland, farms,

and ranches. About 72 percent of the land consists of forests

used for timber, recreation, wildlife habitat, and watershed.

Approximately 17 percent is pasture and range, and less than 2

percent is cropland.

The major soil resource concerns include the hazard of water

erosion, which can be severe if the soils are disturbed by

logging, fires, overgrazing, or cultivation. Other management

concerns include compaction resulting from farming activities,

the impacts of catastrophic wildfire on forestland, and

maintenance of the content of organic matter in the soils. The

soils in the mountain valleys and meadows are susceptible to

gullying and streambank erosion. The older or improperly

designed roads contribute sediment to streams.

Conservation practices on all kinds of land in this MLRA

include measures that control erosion on access roads and

protect riparian areas. Conservation practices on forestland

generally include forest stand improvement, forest site

preparation, reforestation, control of erosion on roads and log

landings, control of competing understory vegetation,

streambank and shoreline protection, riparian area management,

stream corridor habitat protection and improvement, wetland

wildlife management, and prescribed grazing.

Conservation practices on cropland and pasture generally

include irrigation water management, water-control structures,

protection of riparian areas, control of streambank erosion, and

nutrient and pesticide management. Prescribed grazing, fences,

and water management are the most important conservation

practices on rangeland and other grazing land. 

Figure 23-1: Location of MLRA 23 in Land Resource Region D.

23—Malheur High Plateau

This area (shown in fig. 23-1) is in Oregon (67 percent),

Nevada (25 percent), and California (8 percent). It makes up

about 22,895 square miles (59,320 square kilometers). It has no

major cities. The only major highway in this area, U.S. Highway

395, crosses the southern tip of the part of the area in
70 Major Land Resource Areas

California. The Sierra Army Depot Military Reservation

occurs in this MLRA. Malheur Lake and numerous wilderness

study areas and national wildlife refuges also occur in this

MLRA.

Physiography

All of this MLRA is on the Intermontane Plateaus. The

southern two-thirds of the area is in the Great Basin Section of

the Basin and Range Province. Almost all of the northern third

of the area is in the Harney Section of the Columbia Plateaus

Province, and a small part of the northern third is in the Payette

Section of the Columbia Plateau Province. Elevation ranges

from 3,900 to 6,900 feet (1,190 to 2,105 meters) in most of the

area, but it exceeds 9,000 feet (2,745 meters) on some

mountains. This area consists primarily of nearly level to

moderately steep plateaus, basins, and valleys bordered by long,

gently sloping alluvial fans. Occasional north-south trending

fault-block mountain ranges separate the basins. Volcanic

plateaus rise sharply above the valleys. Drainage patterns have

not yet been established on the youngest lava plateaus.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Oregon Closed Basins (1712), 58 percent; Black Rock DesertHumboldt (1604), 23 percent; North Lahontan (1808), 9

percent; Middle Columbia (1707), 6 percent; and Middle Snake

(1705), 4 percent. The area has no major rivers. It consists

mostly of closed basins.

Geology

Most of this area consists of young andesite and basalt layers

(6 to 17 million years old). Older volcanic rocks and marine

and continental sediments are exposed in the mountain ranges.

These north-south trending ranges are uplifted fault blocks. The

basins between the mountains and lava plateaus are filled with

a mixture of Quaternary alluvium, continental sediments, and

volcanic ash. The long alluvial fans consist of coarser alluvium

near the mountains and fine grained sediments at their distal

ends. Playas or shallow lakes are common in the lowest areas

within the closed basins.

Climate

In most of this area, the average annual precipitation is 6 to

12 inches (150 to 305 millimeters). It is as much as 57 inches

(1,450 millimeters), however, in the mountain ranges. The

precipitation is fairly evenly distributed throughout fall, winter,

and spring but is low in summer. Snow can occur throughout

the area in winter. The average annual temperature is 39 to 52

degrees F (4 to 11 degrees C), decreasing with elevation. The

freeze-free period averages 105 days and ranges from 35 to 175

days, decreasing in length with elevation.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 0.2%; ground water, 0.2%

Irrigation—surface water, 88.5%; ground water, 10.2%

Other—surface water, 0.4%; ground water, 0.4%

The total withdrawals average 1,080 million gallons per

day (4,090 million liters per day). About 11 percent is from

ground water sources, and 89 percent is from surface water

sources. Surface water is scarce, except in areas at the higher

elevations where precipitation is greater. Streamflow is erratic

and depends mostly on runoff from melting snow. Most of the

water is used for irrigating grain and hay for cattle feed.

Irrigated areas are on alluvial fans and pluvial lake terraces.

Surface water from mountain runoff is generally of excellent

quality. As the water seeps through the alluvial fan deposits,

salts left in the soil as a result of evapotranspiration are

dissolved. In the wetter years, when springs discharge this

seepage water at the toe of the fan, the water quality is

degraded. As the surface water evaporates on its path to a playa,

the salt concentrations increase, making the water unsuitable

for all uses.

The large supply of ground water in the gravel- and sandfilled valleys and basins is mostly untapped. Little is known

about the quality of this ground water in California and

Nevada. The basin fill deposits in Oregon have soft to

moderately hard water with a median concentration of about

170 parts per million (milligrams per liter) total dissolved

solids. The ground water near the alluvial fans typically has

lower levels of total dissolved solids than the ground water near

playas. Wells closer to the playas typically contain 1,000 or

more parts per million (milligrams per liter) total dissolved

solids. The volcanic rocks are considered to be aquifers, but

they are little used and not much is known about the range of

water quality. Water can be found in layers of rubble, cracks,

and tubes within the lava. Layers of alluvium and continental

sediments occurring between the andesite and basalt flows also

may contain ground water.

Soils

The dominant soil orders in this MLRA are Aridisols and

Mollisols. The soils in the area dominantly have a mesic or

frigid soil temperature regime, an aridic or xeric soil moisture

regime, and mixed or smectitic mineralogy. The soils on

uplands generally are well drained, loamy or clayey, and

shallow or moderately deep. The soils in basins generally are

poorly drained to well drained, loamy or clayey, and very deep.

Locally, large areas have an ashy particle-size class and glassy

mineralogy.
of the United States 71

Shallow Argidurids (Actem series) formed in residuum and

colluvium on hills and tablelands. Moderately deep Argidurids

(Brace series) formed in residuum and alluvium on structural

benches and foothills. Shallow Haplargids (Anawalt and Coztur

series) formed in residuum on hills, mountains, and plateaus.

Moderately deep Haplocambids (Felcher series) and shallow

Haplodurids (Raz series) formed in residuum and colluvium on

mountains and plateaus. Moderately deep Haplocryolls

(Baconcamp series) formed in colluvium on hills and mountain

slopes. Argixerolls (shallow Devada, Ninemile, and Wylo series

and moderately deep Bucklake series) formed in residuum on

hills, plateaus, and mountain slopes. Moderately deep

Palexerolls (Carryback series) formed in colluvium and

residuum on plateaus. Very deep Endoaquolls (Fury and Ozamis

series), Natrargids (Ausmus series), and Halaquepts (Lolak and

Reese series) formed in lacustrine sediments on lake plains.

Very deep Haplocambids (Catlow and Enko series), Natrargids

(Poujade series), and Paleargids (Spangenburg series) formed in

alluvium on lake terraces.

Biological Resources

This area supports a shrub-grass association. Big sagebrush,

low sagebrush, rabbitbrush, needlegrasses, and squirreltail are

common on the plateaus and mountains. Big sagebrush and

basin wildrye are on bottom lands. Spiny hopsage and bud

sagebrush are on the drier sites. Greasewood, saltbush, and

saltgrass grow on salty and sodic soils in basins. Silver

sagebrush grows on moist sites that have intermittent water,

such as areas along the margin of playas. Western juniper is on

rocky sites. Aspen groves occur on moist sites at high

elevations, and isolated stands of Douglas-fir and whitebark

pine also occur in the mountains.

Some of the major wildlife species in this area are elk, mule

deer, bighorn sheep, antelope, migratory birds and waterfowl,

golden eagle, red-tailed hawk, prairie falcon, great horned owl,

long-eared owl, common barn owl, sage grouse, chukar,

meadowlark, and vesper sparrow.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 3%

Grassland—private, 19%; Federal, 65%

Forest—Federal, 3%

Water—private, 2%; Federal, 4%

Other—private, 1%; Federal, 3%

About 75 percent of this area is federally owned. Native

range vegetation covers much of the area. Livestock production

on rangeland is the principal agricultural enterprise. A small

percentage of the area is used for irrigated alfalfa hay, grain,

hay for winter feed, or pasture. Pasture and hay provide

seasonal feed for livestock. Small areas on the upper mountain

slopes are forested.

The major soil resource concerns are control of wind erosion

and reduction of the content of salts and sodium in the areas of

soils used for the production of crops or hay. Conservation

practices on cropland generally include irrigation water

management, crop residue management, and toxic salt

reduction. Prescribed grazing, brush management, and

development of watering facilities are important conservation

practices on rangeland. 

Figure 24-1: Location of MLRA 24 in Land Resource Region D.

24—Humboldt Area

This area (shown in fig. 24-1) is in Nevada (94 percent) and

Oregon (6 percent). It makes up about 12,680 square miles

(32,855 square kilometers). The towns of Winnemucca and

Battle Mountain, Nevada, are along Interstate 80, which crosses

this MLRA. A small portion of the Humboldt-Toiyabe National

Forest and numerous wilderness study areas occur in this area.

The Fort McDermitt Indian Reservation and the very small

Battle Mountain and Winnemucca Indian Reservations also are

in this area.
72 Major Land Resource Areas

Physiography

This MLRA is in the Great Basin Section of the Basin and

Range Province of the Intermontane Plateaus. A series of widely

spaced north-south trending mountain ranges are separated by

wide valleys filled with alluvium and lacustrine materials. The

isolated ranges are dissected, uplifted fault-block mountains.

Elevation ranges from 3,950 to 5,900 feet (1,205 to 1,800

meters) in most of the area, but it is more than 8,850 feet (2,700

meters) on some mountain peaks.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Black Rock Desert-Humboldt (1604), 84 percent; Central

Nevada Desert Basins (1606), 10 percent; and Oregon Closed

Basins (1712), 6 percent. The Humboldt River flows through

this area on its way to the Humboldt Sink.

Geology

Most of this area consists of wide valleys filled with deposits

of alluvium washed in from the adjacent mountain ranges.

Playas occur in the lowest areas in valleys with closed drainage

systems. Most of the valleys, however, are drained by tributaries

to the Humboldt River. Mesozoic and Paleozoic volcanic rocks

and marine and continental sediments are exposed in the

mountain ranges. Some young andesite and basalt layers (6 to

17 million years old) occur at the margins of the mountains.

These north-south trending ranges are uplifted fault blocks.

Alluvial fans consist of coarser alluvium near the mountains

and fine grained sediments at their distal ends.

Climate

In most of this area, the average annual precipitation is 6 to

12 inches (150 to 305 millimeters). It is as much as 40 inches

(1,015 millimeters), however, in the mountain ranges. Most of

the rainfall occurs as high-intensity, convective thunderstorms

in spring and autumn. Precipitation occurs mainly as snow in

winter. Summers are dry. The average annual temperature is 38

to 53 degrees F (3 to 12 degrees C). The freeze-free period

averages 135 days and ranges from 100 to 175 days, decreasing

in length with elevation.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 0.0%; ground water, 0.1%

Irrigation—surface water, 68.6%; ground water, 29.0%

Other—surface water, 1.2%; ground water, 1.0%

The total withdrawals average 985 million gallons per day

(3,730 million liters per day). About 30 percent is from ground

water sources, and 70 percent is from surface water sources. The

low precipitation provides a small amount of water. Surface

water is available from perennial and intermittent streams that

carry snowmelt from the mountains. Late-season surface water

supplies are deficient. Most of the water is used for irrigating

grain and hay grown for cattle feed.

Irrigated areas are on alluvial fans and along streams in the

valleys. Diversions from the Humboldt River are common.

Because of additions of poor-quality drainage water from the

irrigated areas, the quality of water in the Humboldt River

deteriorates as the river flows west. Rye Patch Reservoir, on the

lower reaches of the Humboldt River, in the southwest corner of

this area, is the only large irrigation storage reservoir in this

MLRA. Surface water from mountain runoff is generally of

excellent quality. As the water seeps through the alluvial fan

deposits, salts left in the soil as a result of evapotranspiration

are dissolved. In the wetter years, when springs discharge this

seepage water at the toe of the fan, local surface water quality

can be degraded.

Limited quantities of ground water in valley fill are being

rapidly developed for irrigation of crops. This water is typically

of good quality and generally meets the national standards for

drinking water. In some areas of geothermal activity or in

shallow alluvial-lacustrine and volcanic deposits, high levels of

arsenic (more than 50 parts per billion) exceed the national

standards for drinking water. Ground water from the basin fill

aquifers is slightly hard and has 200 to 400 parts per million

(milligrams per liter) total dissolved solids.

Soils

The dominant soil order in the MLRA is Aridisols. Entisols,

Inceptisols, and Mollisols also are important. The soils in the

area dominantly have a mesic soil temperature regime, an aridic

soil moisture regime, and mixed mineralogy. They generally are

well drained, loamy, and very deep. Torriorthents (Boton series)

formed in loess and alluvium over lacustrine sediments on lake

plains and basin floors. Somewhat poorly drained Halaquepts

(Wendane series) formed in alluvium on flood plains and

terraces. Natrargids (Beoska and Oxcorel series) formed in loess

over alluvium on fan piedmonts and plateaus. Haplocambids

formed in loess over alluvium on alluvial fans and alluvial flats

(Broyles, Orovada, and Weso series) and in alluvium on alluvial

fans and lake terraces (Davey, Enko, and McConnel series).

Shallow Argidurids formed in alluvium on fans and terraces

(Tumtum series) and in loess and alluvium on fan remnants and

plateaus (Dewar series). Moderately deep Haplargids (Roca

series) formed in colluvium and residuum on hills and

mountain slopes. Moderately deep Argixerolls (Reluctan series)
of the United States 73

formed in colluvium and residuum on hills, mountains, and

plateaus.

Biological Resources

This area supports shrub-grass vegetation. In areas where the

average annual precipitation is about 8 inches (200

millimeters) or more, big sagebrush is the characteristic plant.

Low sagebrush is characteristic on some soils with a clayey

subsoil. Thurber needlegrass, bluebunch wheatgrass (scarce on

the drier sites), basin wildrye, squirreltail, Sandberg bluegrass,

forbs, spiny hopsage, and Douglas rabbitbrush are common

associated plants. Locally important are Idaho fescue and

snowberry on sites where moisture is favorable, Utah juniper in

a few high rocky areas, and Indian ricegrass and

needleandthread on sandy soils. Shadscale and bud sagebrush

associated with Indian ricegrass and bottlebrush squirreltail are

dominant on the drier sites. Black greasewood, basin wildrye,

and Nuttall saltbush are locally important on some low terraces

and flood plains. Winterfat is prevalent in some areas.

Some of the major wildlife species in this area are mule deer,

coyote, bobcat, beaver, muskrat, jackrabbit, cottontail, pheasant,

chukar, Hungarian partridge, sage grouse, quail, ducks, and

geese. The Humboldt River supports some warm-water fish.

Trout are in some of the mountain streams.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 3%

Grassland—private, 20%; Federal, 75%

Forest—Federal, 1%

Other—private, 1%

About three-fourths of this area is federally owned. The rest

is used for farms, ranches, industrial enterprises (mining), and

some urban and transportation purposes. Livestock grazing on

native range is the principal agricultural enterprise. About 3

percent of the area, generally consisting of narrow strips along

the major streams and margins of valleys, is used for irrigated

hay, grain, pasture, alfalfa seed, or potatoes. The hay produced

in the area is used principally for winter feeding of resident

livestock.

The major soil resource concerns are control of wind erosion

and reduction of the content of salts and sodium in the soils in

areas used for crops or pasture. The main management

considerations include proper grazing practices and the efficient

use of the available supplies of surface water and ground water.

Conservation practices on cropland generally include irrigation

water management, crop residue management, and toxic salt

reduction. Important practices on rangeland include prescribed

grazing, brush management, and development of watering

facilities. 

Figure 25-1: Location of MLRA 25 in Land Resource Region D.

25—Owyhee High Plateau

This area (shown in fig. 25-1) is in Nevada (52 percent),

Idaho (29 percent), Oregon (16 percent), and Utah (3 percent). It

makes up about 28,930 square miles (74,960 square

kilometers). The city of Elko, Nevada, which is along Interstate

80, is in this MLRA. The Humboldt-Toiyabe and Sawtooth

National Forests and numerous wilderness study areas also

occur in this MLRA. Most of the wilderness study areas are in

the high desert canyon lands of southern Idaho. The Duck

Valley, South Fork, Ruby Valley, and Te-Moak Indian

Reservations are in this area.

Physiography

All of this area lies within the Intermontane Plateaus. The

southern half is in the Great Basin Section of the Basin and

Range Province. This part of the MLRA is characterized by

isolated, uplifted fault-block mountain ranges separated by

narrow, aggraded desert plains. This geologically older terrain

has been dissected by numerous streams draining to the

Humboldt River. The northern half of the area lies within the

Columbia Plateaus Province. This part of the MLRA forms the

southern boundary of the extensive Columbia Plateau basalt

flows. Most of the northern half is in the Payette Section, but

the northeast corner is in the Snake River Plain Section. Deep,

narrow canyons draining into the Snake River have been incised
74 Major Land Resource Areas

into this broad basalt plain. Elevation ranges from 3,000 to

7,550 feet (915 to 2,300 meters) on rolling plateaus and in

gently sloping basins. It is more than 9,840 feet (3,000 meters)

on some steep mountains.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Middle Snake (1705), 49 percent; Black Rock Desert-Humboldt

(1604), 28 percent; Upper Snake (1704), 15 percent; Great Salt

Lake (1602), 5 percent; and Central Nevada Desert Basins

(1606), 3 percent. The Humboldt River, route of a major western

pioneer trail, crosses the southern half of this area. Reaches of

the Owyhee River in this area have been designated as National

Wild and Scenic Rivers.

Geology

The dominant rock types in the area are volcanic. They

include andesite, basalt, and rhyolite. In the north and west

parts of the area, Miocene volcanic rocks dominate and

Cretaceous granitic rocks occur in the mountains. A Mesozoic

igneous and metamorphic rock complex dominates the south

and east parts of the area. Upper and Lower Paleozoic

sediments, including extensive limestone deposits, occur in the

mountains. Only a few narrow valleys occur in this area (2 to 3

percent of the land area). Alluvial fan and basin fill sediments

occur in the valleys.

Climate

The average annual precipitation in most of this area is 7 to

16 inches (180 to 405 millimeters), but it can exceed 50 inches

per year (1,270 millimeters) in the mountains. The amount of

precipitation is lowest in the eastern part of the area and

increases with elevation. Rainfall occurs in spring and

sporadically in summer. Precipitation occurs mainly as snow in

winter. The precipitation is distributed fairly evenly throughout

fall, winter, and spring. The amount of precipitation is lowest

from midsummer to early autumn. The average annual

temperature is 35 to 53 degrees F (2 to 12 degrees C). The

freeze-free period averages 130 days and ranges from 65 to 190

days, decreasing in length with elevation. It is typically less

than 70 days in the mountains.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 0.1%; ground water, 0.1%

Livestock—surface water, 0.2%; ground water, 4.8%

Irrigation—surface water, 49.8%; ground water, 35.5%

Other—surface water, 3.3%; ground water, 6.3%

The total withdrawals average 570 million gallons per day

(2,155 million liters per day). About 47 percent is from ground

water sources, and 53 percent is from surface water sources.

The supply of water from precipitation and streamflow is small

and unreliable, except along the Owyhee, Bruneau, and

Humboldt Rivers. Streamflow depends largely on accumulated

snow in the mountains. Surface water from mountain runoff is

generally of excellent quality and is suitable for all uses.

Precipitation is adequate for dryfarming in a few areas of deep

soils in Idaho.

The basin fill sediments in the narrow alluvial valleys

between the mountain ranges provide some ground water for

irrigation. The alluvial deposits along the large streams have

the most ground water. Based on measurements of water quality

in similar deposits in adjacent areas, the basin fill deposits

probably contain moderately hard water with a concentration of

less than 400 parts per million (milligrams per liter) total

dissolved solids. The carbonate rocks in this area are

considered to be aquifers, but they are little used. The water in

this aquifer is suitable for almost all uses. The concentrations of

total dissolved solids are less than the Nevada drinking water

standard of 1,000 parts per million (milligrams per liter).

Springs are common along the edges of the limestone

outcrops.

Soils

The dominant soil orders in this MLRA are Aridisols and

Mollisols. The soils in the area dominantly have a mesic or

frigid soil temperature regime, an aridic or xeric soil moisture

regime, and mixed or smectitic mineralogy. They generally are

well drained, clayey or loamy, and shallow or moderately deep.

Haplodurids (Bioya and Coonskin series) formed in loess over

alluvium on fan piedmonts and plateaus. Argidurids (Dacker,

Bruncan, and Hunnton series) and some Durixerolls (Donna

and Heckison series) formed in mixed loess and volcanic ash

over alluvium on fan piedmonts and plateaus. Other Durixerolls

(Stampede series) formed in alluvium on alluvial fans and fan

piedmonts. Argidurids (Arbidge and Diawell series) formed in

alluvium on fan piedmonts and stream terraces. Haplargids

formed in residuum and colluvium on hills, mountain slopes,

and plateaus (Vanwyper and Dougal series) and in alluvium on

alluvial fans, ballenas, and plateaus (very deep Wieland and

Owsel series). Some Argixerolls (shallow Cleavage, Gaib, and

Ninemile series and moderately deep Quarz, Mulshoe, and

Sumine series) formed in residuum and colluvium on hills,

plateaus, and mountain slopes. Other Argixerolls (McIvey

series) formed in alluvium or colluvium on fans, hills, and

mountain slopes.

Biological Resources

This area supports shrub-grass vegetation characterized by

big sagebrush or low sagebrush and by bluebunch wheatgrass,

western wheatgrass, or Idaho fescue. Other important plants are

Sandberg bluegrass, foxtail wheatgrass, penstemon, phlox,
of the United States 75

milkvetch, lupine, aster, and rabbitbrush. The high plateaus

support juniper and curl-leaf mountain mahogany and an

understory of dominantly snowberry and ceanothus. Conifers,

aspen, and very large curl-leaf mountain mahogany are in the

Owyhee, Ruby, and Jarbridge Mountains. The conifers include

whitebark pine, Douglas-fir, limber pine, Engelmann spruce,

subalpine fir, and bristlecone pine.

Some of the major wildlife species in this area are mule deer,

bighorn sheep, pronghorn, mountain lion, coyote, bobcat,

badger, river otter, mink, weasel, golden eagle, red-tailed hawk,

ferruginous hawk, Swainson’s hawk, northern harrier, prairie

falcon, kestrel, great horned owl, short-eared owl, long-eared

owl, burrowing owl, pheasant, sage grouse, chukar, gray

partridge, and California quail. Reptiles and amphibians

include western racer, gopher snake, western rattlesnake, sideblotched lizard, western toad, and spotted frog. The species of

fish in the area include bull trout, red band trout, and rainbow

trout.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 1%

Grassland—private, 22%; Federal, 73%

Forest—Federal, 2%

Water—private, 1%

Other—private, 1%

About three-fourths of this area is federally owned. The rest

is mainly in farms and ranches. Livestock production on

rangeland is the main agricultural enterprise. A few areas in

valleys are used for irrigated grain and forage for livestock.

Small areas in Idaho are used for dry-farmed wheat. Open forests

on mountain slopes at high elevations are grazed by livestock

and wildlife.

The major soil resource concerns include accelerated

erosion, runoff, and sedimentation. Forest health and rangeland

quality are additional concerns.

Conservation practices on cropland generally include

irrigation water management, pasture and hayland seeding, and

weed control. The efficiency of irrigation water use can be

improved by sprinkler systems and installation of gated pipe,

field runoff management, and water source development. The

plant species selected for seeding on pasture and hayland

should be those that are suited to the various soil and

environmental conditions. Weed control may include the

removal of noxious and invasive plants followed by seeding

with adapted forage species. Forest health can be enhanced by

practices that include thinning, site preparation, forest stand

improvement, and properly located and constructed forest roads

and landings. Rangeland quality can be maintained or

improved by developing livestock watering facilities, reseeding,

prescribed burning, proper fencing, and weed control. 

Figure 26-1: Location of MLRA 26 in Land Resource Region D.

26—Carson Basin and Mountains

This area (shown in fig. 26-1) is in Nevada (75 percent) and

California (25 percent). It makes up about 6,520 square miles

(16,890 square kilometers). The cities of Carson City, Reno,

and Sparks, Nevada, are in this MLRA. Interstate 80 crosses the

central part of this area. The Plumas, Humboldt-Toiyabe, and

Inyo National Forests occur in the area. The Washoe and RenoSparks Indian Reservations and the western part of the Walker

River Indian Reservation also are in the area.

Physiography

Almost all of this area is in the Great Basin Section of the

Basin and Range Province of the Intermontane Plateaus.

Isolated north-south trending mountain ranges are separated by

aggraded desert plains. The mountains are uplifted fault blocks

with steep side slopes. Most of the valleys are drained by three

major rivers flowing east across this MLRA. A narrow strip

along the western border of the area is in the Sierra Nevada

Section of the Cascade-Sierra Mountains Province of the Pacific

Mountain System. The Sierra Nevada Mountains are primarily a

large fault block that has been uplifted with a dominant tilt to

the west. This structure leaves an impressive wall of mountains

directly west of this area. Parts of this eastern face, but mostly

just the foothills, mark the western boundary of this area.
76 Major Land Resource Areas

Elevation ranges from 3,900 to 6,550 feet (1,190 to 1,995

meters) in valleys and is as high as 13,100 feet (3,995 meters)

on mountain crests.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Central Lahontan (1605), 72 percent; Northern Mojave-Mono

Lake (1809), 16 percent; North Lahontan (1808), 7 percent; and

Central Nevada Desert Basins (1606), 5 percent. The Truckee

River originates at Lake Tahoe and runs through Reno, Nevada,

on its way east to its terminus just outside this area in Pyramid

Lake. The headwaters of the Carson River run through Carson

City, Nevada. This river flows to its terminus just outside this

area in the Carson Sink, below the Lahontan Reservoir. The

East and West Walker Rivers join to form the Walker River in

the southern tip of this area. The Walker River flows into Weber

Reservoir and then on to its terminus, Walker Lake, just outside

this area.

Geology

Mesozoic and Tertiary intrusives are common in this area.

These rocks are granitic near the Sierra Nevada Mountains on

the west side but are typically andesite and basalt in the rest of

the area. There are some young tuffaceous sediments in this

MLRA, and a complex of Mesozoic sediments and volcanic

rocks occurs on the edges of uplifted fault blocks. Alluvium

fills the valleys between the mountains. The major rivers in the

area have reworked the alluvium, forming prominent terraces

and flood plains. There is a level line evident on the higher

slopes marking the former extent of glacial Lake Lahontan.

Climate

The average annual precipitation in this area is 5 to 36 inches

(125 to 915 millimeters), increasing with elevation. Most of the

rainfall occurs as high-intensity, convective storms in spring

and autumn. Precipitation is mostly snow in winter. Summers

are dry. The average annual temperature is 37 to 54 degrees F (3

to 12 degrees C). The freeze-free period averages 115 days and

ranges from 40 to 195 days, decreasing in length with elevation.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 7.6%; ground water, 7.9%

Livestock—surface water, 0.2%; ground water, 0.2%

Irrigation—surface water, 56.2%; ground water, 25.7%

Other—surface water, 1.1%; ground water, 1.0%

The total withdrawals average 935 million gallons per day

(3,530 million liters per day). About 35 percent is from ground

water sources, and 65 percent is from surface water sources. The

low precipitation in the valleys provides little water, but a few

large rivers that have their source in high mountains outside

the area supply water for irrigation and other uses along the

course of the rivers. The reservoirs used principally for storing

irrigation water include Washoe Lake in the headwaters of the

Carson River and Weber Reservoir on the Walker River in

Nevada and Bridgeport Reservoir and Topaz Lake on the

Walker River in California. Surface water from mountain

runoff is generally of excellent quality and is suitable for all

uses.

Limited quantities of ground water in valley fill are being

rapidly developed for urban, industrial, and agricultural uses.

The alluvial deposits along the larger streams contain the most

ground water. This water is of good quality, although the total

dissolved solids can exceed the Nevada drinking water standard

of 1,000 parts per million (milligrams per liter) in some areas.

The basin fill aquifer typically has moderately hard to very

hard water with a concentration of 150 to 1,000 parts per

million (milligrams per liter) total dissolved solids.

Soils

The dominant soil orders in this MLRA are Aridisols and

Mollisols. The soils in the area dominantly have a mesic soil

temperature regime, an aridic or xeric soil moisture regime, and

mixed or smectitic mineralogy. They generally are well drained,

are clayey or loamy and commonly skeletal, and are very

shallow to moderately deep. Argixerolls (Duco and Ister series)

formed in residuum and colluvium on hills and mountain

slopes. Argidurids (Fulstone, Reno, and Smedley series) and

very deep Haplocambids (Haybourne series) formed in

alluvium on alluvial fans, terraces, and piedmonts. Haplargids

(Old Camp and Xman series) and Argidurids (Lapon series)

formed in residuum and colluvium on hills, plateaus, and

mountain slopes.

Biological Resources

This area supports shrub-grass vegetation characterized by

big sagebrush. Low sagebrush and Lahontan sagebrush occur

on some soils. Antelope bitterbrush, squirreltail, desert

needlegrass, Thurber needlegrass, and Indian ricegrass are

important associated plants. Green ephedra, Sandberg

bluegrass, Anderson peachbrush, and several forb species also

are common. Juniper-pinyon woodland is typical on mountain

slopes. Jeffrey pine, lodgepole pine, white fir, and manzanita

grow on the highest mountain slopes. Shadscale is the typical

plant in the drier parts of the area. Sedges, rushes, and

moisture-loving grasses grow on the wettest parts of the wet

flood plains and terraces. Basin wildrye, alkali sacaton,

saltgrass, buffaloberry, black greasewood, and rubber

rabbitbrush grow on the drier sites that have a high

concentration of salts.

Some of the major wildlife species in this area are mule deer,

coyote, beaver, muskrat, jackrabbit, cottontail, raptors,
of the United States 77

pheasant, chukar, blue grouse, mountain quail, and mourning

dove. The species of fish in the area include trout and catfish.

The Lahontan cutthroat trout in the Truckee River is a

threatened and endangered species.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 2%

Grassland—private, 23%; Federal, 58%

Forest—private, 2%; Federal, 9%

Urban development—private, 2%

Water—private, 2%

Other—private, 2%

About two-thirds of this area is federally owned. The rest is

used mainly for farming, ranching, urban development,

industrial enterprises, and transportation. Grazing of livestock

on native grasses and shrubs is the principal agricultural

enterprise. About 2 percent of the total area, principally in

valleys along the major streams, is used for irrigated hay, grain,

tame pasture, onions, potatoes, or garlic. About one-tenth of the

area is forestland on mountain slopes. Some areas formerly used

for farming are being converted to urban uses.

The major soil resource concerns are maintenance of the

content of organic matter and productivity of the soils and the

accelerated erosion resulting from recreational activities and

construction. In some areas the content of salts and sodium in

the soils is a concern. Forest and rangeland health is an

additional management concern.

Conservation practices on cropland generally include

irrigation water management and crop residue management.

Prescribed grazing, brush management, and watering facilities

are important on rangeland. Pasture and hay provide seasonal

feed for livestock. In areas of forestland, forest stand

improvement, forest site preparation, properly located forest

trails and landings, and firebreaks can help to reduce the effects

of catastrophic wildfires and the damage caused by insects and

disease. 

Figure 27-1: Location of MLRA 27 in Land Resource Region D.

27—Fallon-Lovelock Area

This area is almost entirely in Nevada (fig. 27-1). It makes up

about 12,565 square miles (32,560 square kilometers). The

towns of Lovelock, Fallon, Yerington, and Hawthorne are in

this MLRA. Interstate 80 crosses the north part of this area. The

Fallon Naval Air Station is in the area. The Stillwater and

Fallon National Wildlife Refuges and the Pyramid Lake, Walker

River, and Lovelock Indian Reservations also are in the area.

Physiography

This area is in the Great Basin Section of the Basin and

Range Province of the Intermontane Plateaus. Isolated

mountain ranges trending north to south are separated by

broad, aggraded desert plains and valleys. The mountains are

uplifted fault blocks with steep side slopes. The mountains and

valleys are dissected by the Humboldt, Truckee, Carson, and

Walker Rivers and their tributaries. Elevation generally ranges

from 3,300 to 5,900 feet (1,005 to 1,800 meters) in valleys, but

on some mountain peaks it is more than 7,870 feet (2,400

meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Central Lahontan (1605), 45 percent; Central Nevada Desert

Basins (1606), 32 percent; and Black Rock Desert-Humboldt

(1604), 23 percent. The major rivers in the area are, from north

to south, the Humboldt River, the Truckee River, the Carson

River, and the Walker River. The Humboldt River terminates in

the Humboldt Sink, the Truckee River terminates in Pyramid

Lake, the Carson River terminates in the Carson Sink (after

flowing through the Lahontan Reservoir), and the Walker River

terminates in Walker Lake (after flowing through the Weber

Reservoir).
78 Major Land Resource Areas

Geology

Almost half of this area has surface deposits of alluvial

valley fill. The rest has andesite and basalt rocks of different

ages. Mesozoic and Tertiary intrusives are concentrated along

the western border of the area, and Lower Volcanic Rocks (17 to

43 million years old) are common on the eastern side of the

area. Also, some scattered outcrops of Mesozoic sedimentary

and volcanic rocks and tuffaceous sedimentary rocks are in the

mountains within the interior of this MLRA.

Climate

The average annual precipitation is 5 to 10 inches (125 to

255 millimeters) in most of the area but is as much as 19 inches

(485 millimeters) on high mountain slopes. Most of the rainfall

occurs as high-intensity, convective thunderstorms during the

growing season. The amount of precipitation is very low from

summer to midautumn. The precipitation in winter occurs

mainly as snow. The average annual temperature is 43 to 54

degrees F (6 to 12 degrees C). The freeze-free period averages

155 days and ranges from 110 to 195 days, decreasing in length

with elevation.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 0.1%; ground water, 0.1%

Livestock—surface water, 0.3%; ground water, 0.3%

Irrigation—surface water, 76.5%; ground water, 17.7%

Other—surface water, 3.1%; ground water, 2.0%

The total withdrawals average 425 million gallons per day

(1,610 million liters per day). About 20 percent is from ground

water sources, and 80 percent is from surface water sources. The

amount of precipitation is very low, and water for irrigation is

obtained principally from diversions on the four large rivers in

the area and from water stored in the Lahontan, Rye Patch, and

Weber Reservoirs. The irrigated areas are mainly near Fallon,

Lovelock, and Yerington. The surface water is generally

suitable for most uses, but local water-quality problems result

from high concentrations of total dissolved solids and sediment

loads in irrigation return flows. Pyramid Lake and Walker Lake

are terminal lakes used principally for recreation. Much of the

Truckee River is diverted for irrigation, so the Pyramid Lake

level is falling, causing problems for native fish species that use

the Truckee River and the lake.

Ground water is scarce and of poor quality in the major

valleys. Limited supplies of ground water of good or fair

quality in some of the outlying valleys are being rapidly

developed for irrigation. The basin fill aquifers contain very

soft to very hard water that typically has total dissolved solids

of less than 500 parts per million (milligrams per liter). Ground

water pumped from the lower elevations in the valleys, nearer

the playa lakes and sinks, typically has more than 1,000 parts

per million (milligrams per liter) total dissolved solids.

A volcanic rock aquifer in western Churchill County, in the

Carson Sink desert, has ground water suitable for most uses.

Arsenic levels, however, exceed the 50 parts per billion

(micrograms per liter) standard for drinking water.

Soils

The dominant soil orders in this MLRA are Aridisols and

Entisols. The soils in the area dominantly have a mesic soil

temperature regime, an aridic soil moisture regime, and mixed

mineralogy. They generally are well drained, are loamy or

sandy and commonly skeletal, and are shallow to very deep.

Shallow Argidurids (Cleaver series) formed in alluvium on fan

piedmonts. Very deep Natrargids formed in loess- and ashmantled alluvium on fan piedmonts (Dorper series) and in

alluvium on fan remnants and lake terraces (Jerval series).

Shallow Haplargids (Old Camp and Theon series) formed in

residuum and colluvium on hills, plateaus, and mountain

slopes. Very deep Torripsamments formed in alluvium on sand

sheets (Hawsley series) and in sandy eolian material on dunes

(Isolde series). Very shallow Torriorthents (Singatse series)

formed in residuum and colluvium on hills and mountain

slopes. Very deep Torriorthents formed in alluvium on alluvial

fans and terraces (Bluewing and Trocken series) and in mixed

alluvium and lacustrine sediments on basin floors, alluvial

flats, and terraces (Mazuma series).

Biological Resources

This area supports desert shrub vegetation. Shadscale is

widespread. It is mixed with Bailey greasewood on uplands

and with black greasewood and seepweed on the lower sites.

Grasses are generally sparse, although Indian ricegrass is

prominent on the sandy soils. Fourwing saltbush, winterfat,

spiny hopsage, wolfberry, ephedra, dalea, and bud sagebrush

are common shrubs. Basin wildrye, creeping wildrye, alkali

sacaton, saltgrass, black greasewood, rubber rabbitbrush, and

big saltbush are important plants on saline bottom lands and

terraces. A few tule marshes support cattail, bulrushes,

sedges, and rushes. Big sagebrush, along with scattered Utah

juniper and singleleaf pinyon, is associated with Thurber

needlegrass, basin wildrye, Sandberg bluegrass, and squirreltail

on some shallow soils on the higher alluvial fans and mountain

slopes.

Some of the major wildlife species in this area are feral

horse, mule deer, antelope, kit fox, bobcat, black-tailed

jackrabbit, antelope ground squirrel, kangaroo rat, bushy-tailed

woodrat, desert mouse, Pacific rattlesnake, gopher snake, whiptailed lizard, sagebrush lizard, sage grouse, chukar, loggerhead

shrike, Brewer’s sparrow, sage thrasher, blue-grey gnat-catcher,

and American kestrel. The Lahontan cutthroat trout and cui-ui
of the United States 79

are two threatened and endangered fish species in the lower

reaches of the Truckee River.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 2%

Grassland—private, 24%; Federal, 64%

Forest—Federal, 4%

Water—private, 2%; Federal, 2%

Other—private, 2%

More than two-thirds of this area is federally owned land,

large tracts of which are used for training and testing purposes

by the Armed Forces. The rest is in farms and ranches. Livestock

production on rangeland is the principal agricultural enterprise.

A small percentage of the area is used for irrigated alfalfa

(including alfalfa seed), grain, garlic, or onions.

The major soil resource concerns are wind erosion and the

content of salts and sodium in the soils. Conservation practices

on cropland generally include irrigation water management,

toxic salt reduction, and crop residue management. These

practices help to reduce the hazard of wind erosion and increase

the available water capacity of the soils. Conservation practices

on rangeland generally include development of watering

facilities and prescribed grazing. 

Figure 28A-1: Location of MLRA 28A in Land Resource Region D.

28A—Great Salt Lake Area

This area (shown in fig. 28A-1) is in Utah (82 percent),

Nevada (16 percent), and Idaho (2 percent). It makes up about

36,775 square miles (95,300 square kilometers). Salt Lake City,

Logan, Ogden, Provo, Richfield, and Cedar City, Utah, and

Malad City and Preston, Idaho, are in this MLRA. Interstate 80

crosses the northern end of the MLRA, and Interstate 15

parallels the eastern border. Interstate 84 crosses the northern

tip, and Interstate 70 ends at Interstate 15 in the south end of

the MLRA. Several national forests occur in this MLRA,

including the Caribou, Dixie, Wasatch-Cache, HumboldtToiyabe, and Fish Lake National Forests. The Deseret Test

Center and the Desert Range Experiment Station, including the

Biosphere Reserve, are in this area. The Hill and Wendover Air

Force Ranges, the Tooele Military Depot, and the Dugway

Proving Grounds also are in this area. The Skull Valley Indian

Reservation is in the area. The Bonneville Salt Flats

Speedway, used by experimental cars for setting land speed

records, also is in the area. The Golden Spike National Historic

Site (joining point for the first transcontinental railroad) is in

this MLRA.

Physiography

This area is the farthest eastern extent of the Great Basin

Section of the Basin and Range Province of the Intermontane

Plateaus. It is an area of nearly level basins between widely

separated mountain ranges trending north to south. The basins

are bordered by long, gently sloping alluvial fans. The

mountains are uplifted fault blocks with steep side slopes. They

are not well dissected because of low rainfall in the MLRA. A

large salt desert playa is south and west of Great Salt Lake.

Most of the valleys in this MLRA are closed basins containing

sinks or playa lakes. Elevation ranges from 3,950 to 6,560 feet

(1,205 to 2,000 meters) in the basins and from 6,560 to 11,150

feet (2,000 to 3,400 meters) in the mountains.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Great Salt Lake (1602), 58 percent; Escalante Desert-Sevier

Lake (1603), 28 percent; Central Nevada Desert Basins (1606),

6 percent; Bear (1601), 5 percent; and Lower Colorado-Lake

Mead (1501), 3 percent. The Jordan, Bear, and Weber Rivers,

the main rivers in this area, all terminate in Great Salt Lake. The

Sevier River is in the south half of the area. Numerous creeks

drain the Wasatch Mountain front directly east of Salt Lake

City, and many terminate in Great Salt Lake directly west of

Salt Lake City.
80 Major Land Resource Areas

Geology

Most of this area has alluvial valley fill and playa lakebed

deposits at the surface. Great Salt Lake is all that remains of

glacial Lake Bonneville, which covered this area during the

most recent ice age. A level line on some mountain slopes

indicates the former extent of this glacial lake. The uplifted

mountains have exposed some Precambrian rocks at their

margins. Most of the mountains in the interior of this area

consist of tilted blocks of marine sediments from Cambrian to

Mississippian age. There are no rocks representing the

Mesozoic era in this area. Scattered outcrops of Tertiary

continental sediments and volcanic rocks are throughout the

area. These units are concentrated on the east and west edges of

the area. The Tertiary intrusives are the dominant rock types at

the southern end of the MLRA.

Climate

The average annual precipitation is 5 to 12 inches (125 to

305 millimeters) in the valleys and is as much as 49 inches

(1,245 millimeters) in the mountains. Most of the rainfall

occurs as high-intensity, convective thunderstorms during the

growing season. The driest period is from midsummer to early

autumn. Precipitation in winter typically occurs as snow. The

average annual temperature is 39 to 53 degrees F (4 to 12

degrees C). The freeze-free period averages 165 days and ranges

from 110 to 215 days, decreasing in length with elevation.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 5.5%; ground water, 8.5%

Livestock—surface water, 1.2%; ground water, 0.8%

Irrigation—surface water, 65.3%; ground water, 14.5%

Other—surface water, 1.0%; ground water, 3.2%

The total withdrawals average 3,575 million gallons per day

(13,530 million liters per day). About 27 percent is from ground

water sources, and 73 percent is from surface water sources.

Water is scarce. For the most part, streams are small and

intermittent and depend on sources in the higher mountains.

Reservoirs are used to store water in the mountains east of this

area for irrigation in the flatter areas of this MLRA. As an

example, the Sevier River, in the southern part of this area, is

the most heavily used river in the United States. Almost 99

percent of its total flow is used before it reaches its terminus in

the mostly dry Sevier Lake. The surface water from the

mountains is of good quality, and its use generally is not

limited. Irrigation return flows raise the levels of dissolved salts

and suspended sediments, causing some contamination.

Both surface water and ground water are used for irrigation.

Use of deep wells is limited by a high cost. Shallow wells in the

basin and valley fill aquifers provide almost all of the ground

water used in this area. This shallow ground water generally

contains less than 1,000 parts per million (milligrams per liter)

total dissolved solids. Along the northeastern border of this

area, near the Wasatch Front where the alluvial aquifers are

recharged, ground water is much lower in dissolved salts

(typically less than 250 parts per million) and is a primary

source of drinking water for the populated areas all along the

Wasatch Front. The ground water becomes almost saline near

the playa lakes west of the recharge zone. A basin fill deposit

near Sevier Lake and the ground water in the Rush Valley area

of Tooele County contain high levels of arsenic.

Soils

The dominant soil orders in this MLRA are Aridisols,

Entisols, and Mollisols. The soils in the area dominantly have a

mesic or frigid soil temperature regime, an aridic or xeric soil

moisture regime, and mixed mineralogy. They generally are

well drained or somewhat excessively drained, loamy or loamyskeletal, and very deep.

Calcixerolls formed in alluvium on alluvial fan remnants and

lake terraces (Abela series) and in alluvium and lacustrine

sediments on lake terraces (Collinston series). Moderately deep

Haploxerolls (Middle series) formed in residuum on mountain

slopes. Deep and very deep Haploxerolls (Ririe and Rexburg

series) formed in loess and silty alluvium on fans, terraces,

foothills, and basalt plains. Shallow Haploxerolls (Hymas

series) to very deep Haploxerolls (Hondoho series) formed in

colluvium and residuum derived from limestone on mountains

and foothills. Torriorthents formed in alluvium on alluvial fans

and beach plains (Cliffdown series) and in alluvium mixed with

lacustrine sediments on alluvial flats and fans, lake terraces, and

lake plains (Timpie and Tooele series). Poorly drained

Aquisalids (Saltair series) formed in alluvium and lacustrine

sediments on lake plains and basin floors. Torripsamments

(Yenrab series) formed in sandy eolian material on dunes.

Haplocalcids formed in residuum on hills and mountains

(shallow Amtoft series); in alluvium and colluvium on alluvial

fans, terraces, and hills (Hiko Peak series); in mixed alluvium

and lacustrine sediments on alluvial fans, terraces, and lake

plains (Taylorsflat series); and in lacustrine sediments on lake

terraces (Thiokol series). Natrargids (Skumpah series) formed in

alluvium on alluvial fans and flats.

Biological Resources

This area supports desert shrub, shrub-grass, and woodland

vegetation. In areas where the average annual precipitation is

less than about 200 millimeters, the soils support shadscale,

winterfat, black sagebrush, and associated grasses, such as

Indian ricegrass and squirreltail. Greasewood and Nuttall

saltbush grow on soils having a high content of salts or sodium.

In areas where the average annual precipitation is 200 to 300
of the United States 81

millimeters, the soils support big sagebrush, shadscale,

winterfat, and associated grasses, such as bluebunch

wheatgrass, Indian ricegrass, and bluegrasses. In areas where the

average annual precipitation is more than 300 millimeters, the

soils support Utah juniper, singleleaf pinyon, big sagebrush,

bluebunch wheatgrass, bluegrasses, and needleandthread. A

large, nearly barren area west of Great Salt Lake has a very

sparse cover of pickleweed, seepweed, and greasewood.

Some of the major wildlife species in this area are mule deer,

jackrabbit, cottontail, Cooper’s hawk, American kestrel, redtailed hawk, prairie falcon, rough-legged hawk, Swainson’s

hawk, and chukar. Brine shrimp occur in Great Salt Lake, and

warm-water species of fish occur in other freshwater lakes in

the valleys. Mountain streams in the Wasatch Mountains are

inhabited by trout.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 6%

Grassland—private, 21%; Federal, 44%

Forest—private, 2%; Federal, 12%

Urban development—private, 2%

Water—private, 7%; Federal, 2%

Other—private, 4%

About three-fifths of this area is federally owned land, large

tracts of which are used for training and testing purposes by the

Armed Forces and the Nuclear Regulatory Commission. A large

area west and southwest of Great Salt Lake is a salty playa. The

rest of the area is in farms and ranches. Livestock production on

rangeland is a principal agricultural enterprise in the west. The

production of desert shrubs and grasses is very low. In most of

the area, the extent of the livestock industry is determined

largely by the amount of hay, pasture, and grain that can be

produced under irrigation from limited water supplies. About 5

percent of the area is irrigated cropland or hayland used for

alfalfa, small grain (wheat, barley, oats, and triticale), Austrian

winter peas, corn for grain or silage, potatoes, vegetables

(onions, pumpkins, sweet corn, peas, and squash), and fruits

(apples, peaches, pears, apricots, and cherries). A small portion

of the irrigated land is used for pasture. About 5 percent is used

for production of dryland winter wheat and safflower.

The management concerns on rangeland include forage

production and the efficient use of range vegetation. The

rangeland in the area is increasingly impacted by invasive

nonnative plants.

The management concerns on dry-farmed cropland include

productivity, wind erosion, water erosion, moisture

management, and weed control. The management concerns on

irrigated cropland and hayland include productivity, the

efficient use of limited water supplies, control of irrigationinduced erosion, and nutrient and pest management. Soil tilth,

compaction, and maintenance of the content of organic matter

in the soils are additional concerns on irrigated and dry-farmed

cropland.

The management concerns on irrigated pasture include

productivity, proper grazing use, efficient use of limited water

supplies, nutrient management, and weed control.

Conservation practices on rangeland generally include brush

management, rangeland seeding, prescribed grazing, fencing,

development of watering facilities, and erosion control.

Conservation practices on dry-farmed cropland generally

include terraces, sediment-control basins, summer fallow

tillage, crop residue management, pest management, and

nutrient management. Conservation practices on irrigated

cropland and hayland include irrigation system improvement,

irrigation water management, no-till hayland planting, forage

harvest management, nutrient management, windbreaks, and

pest management. Conservation practices on irrigated pasture

generally include irrigation system improvement, irrigation

water management, pasture planting, development of watering

facilities, fencing, prescribed grazing, nutrient management,

and pest management. 

Figure 28B-1: Location of MLRA 28B in Land Resource Region D.

28B—Central Nevada Basin and Range

This area is entirely in Nevada (fig. 28B-1). It makes up

about 23,555 square miles (61,035 square kilometers). The

town of Ely, Nevada, is in this MLRA. Interstate 80 crosses the
82 Major Land Resource Areas

northeastern tip of the area. One of the world’s largest open-pit

mines, the Ruth Copper Pit, is directly west of Ely. Portions of

the Humboldt and Toiyabe National Forests occur in this area.

The Odgers Ranch, Goshute, and Duckwater Indian

Reservations and the Great Basin National Park also are in this

area.

Physiography

This area is in the Great Basin Section of the Basin and

Range Province of the Intermontane Plateaus. It is an area of

nearly level, aggraded desert basins and valleys between a series

of mountain ranges trending north to south. The basins are

bordered by long, gently sloping to strongly sloping alluvial

fans. The mountains are uplifted fault blocks with steep side

slopes. They are not well dissected because of a low amount of

rainfall in the area. Many of the valleys in this MLRA are

closed basins containing sinks or playas. Elevation ranges from

4,900 to 6,550 feet (1,495 to 1,995 meters) in the valleys and

basins and from 6,550 to 11,900 feet (1,995 to 3,630 meters) in

the mountains.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Central Nevada Desert Basins (1606), 82 percent; Black Rock

Desert-Humboldt (1604), 7 percent; Lower Colorado-Lake

Mead (1501), 6 percent; and Great Salt Lake (1602), 5 percent.

The MLRA has no major rivers. The Duck River is north and

east of Ely.

Geology

The mountains in the southern half of this area are

dominated by andesite and basalt rocks that were formed in the

Miocene and Oligocene. Paleozoic and older carbonate rocks

are prominent in the mountains to the north. Scattered outcrops

of older Tertiary intrusives and very young tuffaceous sediments

are throughout this area. The valleys consist mostly of alluvial

fill, but lake deposits are at the lowest elevations in the closed

basins. The alluvial valley fill consists of cobbles, gravel, and

coarse sand near the mountains in the apex of the alluvial fans.

Sands, silts, and clays are on the distal ends of the fans.

Climate

The average annual precipitation is 4 to 12 inches (100 to

305 millimeters) in most areas on the valley floors. It is about 8

to 36 inches (205 to 915 millimeters) in the mountains. Most of

the rainfall occurs as high-intensity, convective thunderstorms

during the growing season. The driest period is from

midsummer to midautumn. The average annual temperature is

34 to 52 degrees F (1 to 11 degrees C). The freeze-free period

averages 125 days and ranges from 80 to 170 days, decreasing

in length with elevation.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 0.0%; ground water, 0.4%

Irrigation—surface water, 86.8%; ground water, 9.6%

Other—surface water, 0.1%; ground water, 3.0%

The total withdrawals average 520 million gallons per day

(1,970 million liters per day). About 13 percent is from ground

water sources, and 87 percent is from surface water sources.

Water is scarce. Most streams are small and intermittent and

depend on sources in the higher mountains. A few small

reservoirs have been constructed throughout the area for storage

of water for irrigation and recreation purposes. The surface

water from the mountains is generally of good quality, and its

use is not limited. Irrigation return flows raise the levels of

dissolved salts and suspended sediments in some streams,

causing some contamination.

Both surface water and ground water are used for irrigation.

Shallow wells in the basin and valley fill aquifers provide

almost all of the ground water used in this area. This shallow

ground water generally contains less than 1,000 parts per

million (milligrams per liter) total dissolved solids. On the

alluvial fan deposits near the mountains, where the valley fill

aquifers are recharged, ground water is much lower in dissolved

salts (typically less than 500 parts per million). The ground

water becomes almost saline near the playas far away from the

recharge zone.

The carbonate rock in this area is considered to be an

aquifer. Use of this aquifer is limited because of the expense of

drilling deep wells. Water from the carbonate rock is suitable

for most uses and is considered to be hard or very hard. The

concentrations of total dissolved solids are generally less than

the Nevada drinking water standard of 1,000 parts per million

(milligrams per liter).

Soils

The dominant soil orders in this MLRA are Aridisols,

Entisols, and Mollisols. The soils in the area dominantly have a

mesic soil temperature regime, an aridic or xeric soil moisture

regime, and mixed or carbonatic mineralogy. They generally

are well drained, loamy or loamy-skeletal, and shallow to very

deep. Moderately deep Calcixerolls (Cavehill series), shallow

Haplocalcids (Pookaloo and Tecomar series), and shallow

Torriorthents (Zimbob series) formed in residuum and

colluvium on mountain slopes and hills. Very deep

Haplocalcids (Kunzler and Wintermute series) formed in

alluvium on alluvial fans, fan terraces, and stream terraces.

Torriorthents (Katelana and Sheffit series) formed in alluvium

on alluvial flats and lake plains. Shallow Haplodurids (Palinor
of the United States 83

and Shabliss series) and shallow Durixerolls (Urmafot series)

formed in alluvium on alluvial fan piedmonts, terraces, and

ballenas.

Biological Resources

This area supports saltbush-greasewood, big sagebrush, and

pinyon-juniper woodland vegetation in the progression from the

lowest to the highest elevation and precipitation. Shadscale, in

association with bud sagebrush, spiny hopsage, ephedra,

winterfat, fourwing saltbush, Indian ricegrass, squirreltail, and

galleta, characterizes the saltbush-greasewood type. With an

increase in moisture, plants associated with shadscale are

replaced by needlegrasses, bluegrasses, bluebunch or beardless

wheatgrass, basin wildrye, and forbs. Black greasewood and

Nuttall saltbush are important on some sites. Big sagebrush and

black sagebrush, which grows on soils that are shallow to an

indurated pan or to bedrock, are dominant. In the pinyonjuniper woodland, bitterbrush, serviceberry, and snowberry

grow in association with Utah juniper and singleleaf pinyon.

The highest elevations support thickets of curl-leaf mountain

mahogany and small amounts of mixed conifer forest with

limber, bristlecone, or ponderosa pine, Douglas-fir, or white

fir.

On bottom lands, basin wildrye, creeping wildrye, alkali

sacaton, wheatgrasses, bluegrasses, sedges, and rushes are

typical. Black greasewood, rubber rabbitbrush, and big

sagebrush grow on the drier sites. Inland saltgrass, alkali

sacaton, black greasewood, rubber rabbitbrush, and big saltbush

typify the vegetation on strongly saline-alkali soils.

Some of the major wildlife species in this area are mule deer,

coyote, bobcat, beaver, jackrabbit, cottontail, sage grouse,

chukar, and quail. The species of fish in the area include trout,

dace, shiners, and suckers.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—private, 5%; Federal, 75%

Forest—Federal, 20%

More than nine-tenths of this area is federally owned. The

rest is mainly in farms and ranches. Livestock grazing of native

grasses and shrubs on rangeland is the principal agricultural

enterprise. In most of the area, the extent of the livestock

industry is determined largely by the amount of hay, pasture,

and grain that can be produced under irrigation from the small

supply of local water. The irrigated land makes up 1 percent or

less of the total area. About one-fifth of the area is pinyonjuniper woodland on mountain slopes.

The major soil resource concerns are the hazard of wind

erosion, the content of salts and sodium in the soils,

management of soil moisture, and forest and rangeland health.

Other management concerns are the efficient use of the

rangeland vegetation and limited water supplies and control of

erosion in critical areas.

Conservation practices on cropland generally include

irrigation water management, crop residue management, and

toxic salt reduction. Conservation practices on rangeland

include prescribed grazing, brush management, and

development of watering facilities. Pasture and hay provide

seasonal feed for livestock. In areas of forestland, forest stand

improvement, forest site preparation, properly located forest

trails and landings, and firebreaks can help to reduce the effects

of catastrophic wildfires and the damage caused by insects and

disease. 

Figure 29-1: Location of MLRA 29 in Land Resource Region D.

29—Southern Nevada Basin and Range

This area (shown in fig. 29-1) is in Nevada (73 percent),

California (25 percent), and Utah (2 percent). It makes up about

26,295 square miles (68,140 square kilometers). The towns of

Lone Pine, California, and Tonopah, Nevada, are in this

MLRA. U.S. Highways 6, 95, and 395 cross the area.

Numerous national forests occur in the area, including the San

Bernardino, Angeles, Sequoia, Inyo, Humboldt-Toiyabe, and

Dixie National Forests. Many wilderness study areas and

wildlife refuges are in this MLRA. Portions of Death Valley

National Monument, the Nuclear Regulatory Commission’s

Nevada Test Site, the Hawthorne Ammunition Depot, and the
84 Major Land Resource Areas

Nellis Air Force Range in Nevada and the China Lake Naval

Weapons Center in California also are in this MLRA. The

northeast part of the Paiute Indian Reservation and the southern

third of the Walker River Indian Reservation are in the part of

this MLRA in Nevada, and the Lone Pine, Fort Independence,

and Big Pine Indian Reservations are in the part in California.

Physiography

This area is in the Great Basin Section of the Basin and

Range Province of the Intermontane Plateaus. Owens Valley

and Death Valley in California mark the farthest western extent

of the Great Basin Section in the Basin and Range Province.

This MLRA is an area of broad, nearly level, aggraded desert

basins and valleys between a series of mountain ranges trending

north to south. The basins are bordered by sloping fans and

terraces. The mountains are uplifted fault blocks with steep side

slopes. They are not well dissected because of a low amount of

rainfall in the MLRA. Most of the valleys in this MLRA are

closed basins containing sinks or playa lakes. Elevation ranges

from 1,950 to 5,600 feet (595 to 1,705 meters) in the valleys.

On some high mountain peaks, it is more than 9,400 feet (2,865

meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Central Nevada Desert Basins (1606), 58 percent; Northern

Mojave-Mono Lake (1809), 28 percent; Lower Colorado-Lake

Mead (1501), 11 percent; Central Lahontan (1605), 2 percent;

and Tulare-Buena Vista Lakes (1803), 1 percent. The Owens

River and Owens Lake occur in this MLRA. Intermittent and

ephemeral streams in Nevada typically end in dry playa lakes.

Geology

The mountains in this area are dominated by Pliocene and

Miocene andesite and basalt rocks. Paleozoic and Precambrian

carbonate rocks are prominent in the mountains. Scattered

outcrops of older Tertiary intrusives and very young tuffaceous

sediments (Pliocene and Miocene) are in the western and

eastern thirds of this MLRA. The valleys consist mostly of

alluvial fill, but playa deposits are at the lowest elevations in the

closed basins. The alluvial valley fill consists of cobbles,

gravel, and coarse sand near the mountains in the apex of the

alluvial fans. Sands, silts, and clays are on the distal ends of the

fans.

Climate

The average annual precipitation is 3 to 12 inches (75 to 305

millimeters) in most of this area. It ranges from 12 to 29 inches

(305 to 735 millimeters), however, on the higher mountain

slopes. Most of the rainfall occurs as high-intensity, convective

thunderstorms during the growing season. Summers are dry, but

sporadic storms are common in July and August. The average

annual temperature is 28 to 72 degrees F (-2 to 22 degrees C),

decreasing with elevation. The freeze-free period averages 205

days and ranges from 80 to 335 days, decreasing in length with

elevation.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 0.1%; ground water, 1.7%

Irrigation—surface water, 34.5%; ground water, 53.3%

Other—surface water, 0.6%; ground water, 9.7%

The total withdrawals average 220 million gallons per day

(815 million liters per day). About 65 percent is from ground

water sources, and 35 percent is from surface water sources.

Precipitation is sparse. Most of the streams are small and

intermittent and depend on sources in the higher mountains.

The surface water from the mountains is generally of good

quality, and its use is not limited near the mountains. The

quality of this water is naturally degraded by dissolved salts

picked up as streams cross areas of valley fill to their terminus

in a playa lake. Irrigation return flows raise the levels of

dissolved salts and suspended sediments in some streams,

causing some contamination. Historically, the Owens River

flowed into Owens Lake in this MLRA. Today, most of the

Owens River is diverted into the Haiwee Reservoir, bypassing

Owens Lake, and then is diverted into the Los Angeles

Aqueduct for use as drinking water in southern California

coastal cities.

Ground water in this area is scarce but is being rapidly

developed. Most of the ground water in California is controlled

by Los Angeles and is not available for local use. Shallow wells

in the basin and valley fill aquifers provide almost all of the

ground water used in this area. This shallow ground water

generally contains less than 1,000 parts per million (milligrams

per liter) total dissolved solids. On the alluvial fan deposits

near the mountains, where the valley fill aquifers are recharged,

ground water is much lower in dissolved salts (typically less

than 500 parts per million). The ground water becomes almost

saline near the playa lakes far away from the recharge zone.

A volcanic rock aquifer is in the south-central part of this

area. It is used very little, and no data about quality of the water

are available. The carbonate rocks in this area also are

considered to be aquifers. Use of these aquifers is limited. Water

from the carbonate rocks is suitable for most uses and is

considered to be hard or very hard. The concentrations of total

dissolved solids are generally less than the Nevada drinking

water standard of 1,000 parts per million (milligrams per liter).
of the United States 85

Soils

The dominant soil orders in this MLRA are Aridisols and

Entisols. Mollisols also are important in the mountainous areas.

The soils in the area dominantly have a mesic soil temperature

regime, an aridic or xeric soil moisture regime, and mixed

mineralogy. They generally are very shallow to very deep, well

drained or somewhat excessively drained, and loamy-skeletal or

sandy-skeletal. Haplargids formed in alluvium on alluvial fans

and fan piedmonts (Ardivey and Unsel series) and in residuum

and colluvium on hills, mountains, and plateaus (Downeyville,

Gabbvally, and Stewval series). Haplocalcids (Candelaria

series) formed in alluvium on ballenas and fan piedmonts.

Haplocambids (Koyen series) formed in alluvium on fan

piedmonts and alluvial fans. Argidurids (Handpah and Zadvar

series) and Haplodurids (Ursine series) formed in alluvium on

fan piedmonts and fan remnants. Torriorthents formed in

residuum and colluvium on hills and mountains (Blacktop,

Kyler, and Pintwater series) and in alluvium on alluvial flats,

fans, and fan piedmonts (Gynelle and Wardenot series).

Torrifluvents (Cirac series) formed in alluvium on alluvial flats

and fans. Shallow Argixerolls formed in residuum and

colluvium on hills and mountains (Bellehelen series).

Biological Resources

This area supports desert shrub vegetation. The major

vegetation consists of saltbush and greasewood. Shadscale is

widespread. It is associated with bud sagebrush, Bailey

greasewood (in the west), gray molly kochia, spiny hopsage,

wolfberry, ephedra, dalea, fourwing saltbush, winterfat,

horsebrush, galleta, and Indian ricegrass. On the warmer sites,

shadscale is associated with white bursage, spiny menodora,

Joshua-tree, and blackbrush. Black greasewood is dominant on

low-lying saline-alkali soils. In areas of higher precipitation,

big sagebrush and black sagebrush are common and are

associated with Indian ricegrass and galleta. Pinyon-juniper

woodland is prevalent in the mountains. Associated plants

include black sagebrush, big sagebrush, blackbrush, bitterbrush,

cliffrose, and other shrubs and a variety of grasses and forbs.

Some of the major wildlife species in this area are mule deer,

coyote, kit fox, bobcat, jackrabbit, cottontail, kangaroo rat,

snakes, lizards, golden eagle, hawks, and chukar. The species of

fish in the area include brook trout, brown trout, and bass.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—private, 4%; Federal, 86%

Forest—Federal, 9%

Other—private, 1%

Nearly all of this area is federally owned land, much of

which is used for training and testing purposes by the Armed

Forces and the Nuclear Regulatory Commission. Less than 1

percent of the area, mostly in the valleys, is irrigated. Much of

the irrigated acreage is used for hay and grain for livestock.

High mountain areas consist of pinyon-juniper woodland.

Native grasses and shrubs in areas of rangeland are grazed by

livestock.

The major soil resource concerns in this area are control of

wind erosion and reduction of the content of salts and sodium in

the soils. Management concerns include proper use of

rangeland, erosion control, and efficient use of the scarce water

supplies.

Conservation practices on cropland generally include

irrigation water management and toxic salt reduction. Also,

windbreaks and crop residue management reduce the hazard of

wind erosion and increase the available water capacity of the

soils. Development of watering facilities and prescribed grazing

are important practices on rangeland. 

Figure 30-1: Location of MLRA 30 in Land Resource Region D.

30—Mojave Desert

This area (shown in fig. 30-1) is in California (59 percent),

Nevada (28 percent), Arizona (12 percent), and Utah (1 percent).

It makes up about 43,750 square miles (113,370 square

kilometers). Lancaster, Palmdale, Victorville, Apple Valley, and

Barstow, California, Bullhead City and Kingman, Arizona, and

Las Vegas, Nevada, are in this MLRA. Interstate 15 connects
86 Major Land Resource Areas

Las Vegas and Barstow in this area. Interstate 40 connects

Kingman and Barstow. Interstate 40 terminates in Barstow,

where it intersects with Interstate 15. The Lake Mead National

Recreation Area is along the Colorado River, which forms the

border between Nevada and Arizona in this MLRA. The

Mojave National Preserve, Joshua Tree and Death Valley

National Parks, and numerous wilderness study areas and

recreational areas occur in this sparsely populated MLRA.

Numerous military reservations are in the area, including

Edwards Air Force Base, Fort Irwin, China Lake Naval

Weapons Center, Goldstone Communications Complex, and

Twenty-Nine Palms Marine Corps Base in California and Nellis

Air Force Range and Nellis and Indian Springs Air Force Bases

in Nevada.

Physiography

This area is in the Basin and Range Province of the

Intermontane Plateaus. Most of the MLRA is in the Sonoran

Desert Section of this province. The northern third is in the

Great Basin Section, and the southeastern part is in the Mexican

Highland Section. A small part of the southwest corner is in

the Salton Trough Section. Broad basins, valleys, and old

lakebeds make up most of the area, but widely spaced

mountains trending north to south occur throughout the area.

Isolated, short mountain ranges are separated by an aggraded

desert plain. The mountains are fault blocks that have been

tilted up. Long alluvial fans coalesce with dry lakebeds

between some of the ranges. Elevation ranges from 282 feet (85

meters) below sea level in Death Valley to 3,950 feet (1,205

meters) above sea level in valleys and basins. The lowest

elevation occurring on dry land in the world, 282 feet (85

meters) below sea level, occurs in the Badwater Basin in Death

Valley. Some mountain ranges have peaks that exceed 11,100

feet (3,385 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Northern Mojave-Mono Lake (1809), 40 percent; Lower

Colorado-Lake Mead (1501), 23 percent; Southern MojaveSalton Sea (1810), 17 percent; Central Nevada Desert Basins

(1606), 11 percent; and Lower Colorado (1503), 9 percent. The

Colorado River crosses the eastern end of this area. Other rivers

include the Armagosa and Mojave Rivers.

Geology

Most of this area is underlain by Quaternary (Pleistocene to

Recent) alluvial deposits on alluvial fans and valley floors.

Recent alluvial fans and remnant alluvial fan terraces typically

grade from boulder-strewn deposits and coarse desert pavement

near the fan apex to finer grained sands, silts, and clays at the

distal ends. Playas are at the lowest elevations in the closed

basins. They commonly have eolian accumulations along their

downwind fringes. Water from shallow subsurface flow and

from surface flows that periodically fill the playa basins

evaporates, leaving accumulations of evaporite minerals,

including salts and borates. Most of the domestic production of

borate minerals and boron in the United States comes from

surface and underground mines in this MLRA. Upland areas in

the MLRA consist of isolated mountain ranges variably

underlain by pre-Cenozoic metamorphic and igneous rocks,

Paleozoic carbonates, Mesozoic granitics, and Cenozoic

nonmarine sedimentary and volcanic deposits. Valuable

deposits of silver, gold, talc, and other commodities occur

throughout the area, particularly where granitic magma intruded

into older sedimentary rocks.

The geology of this area is dynamic and complex. Cenozoic

to Recent tectonic extension and crustal thinning have resulted

in granitic and other igneous intrusions, geologically recent

volcanism, and normal and detachment faulting and associated

seismicity. The tectonic setting of this area includes

translational movement occurring along the Garlock Fault and

along right-lateral strike-slip faults that comprise the Eastern

California Shear Zone.

Climate

The average annual precipitation is 2 to 8 inches (50 to 205

millimeters) in most of this extremely dry MLRA. It exceeds 37

inches (940 millimeters) in some scattered areas at the higher

elevations in Nevada and southwestern Utah. Most of the

rainfall occurs in the winter months as low-intensity

precipitation from Pacific storms that are frontal in nature.

High-intensity, convective thunderstorms can occur during the

summer, but they contribute little to soil moisture. These storms

occur more frequently in the eastern part of the area, where they

contribute more to soil moisture. Snow is not very common and

usually is on the ground for very short periods at the lower

elevations, but the highest elevations may have snow for several

weeks at a time in the winter. The average annual snowfall

ranges from nearly 0 inches in the lowest deserts to more than

30 inches (760 millimeters) at the highest elevations of the

Spring Mountains directly west of Las Vegas.

The average annual temperature ranges from 43 degrees F (6

degrees C) in the highest mountains to 76 degrees F (25 degrees

C) in areas along the Colorado River in California, Nevada, and

Arizona. Most of the lowest deserts have a growing season of

nearly 365 days per year, especially along the Colorado River,

whereas other desert areas have a freeze-free period of 200 to

330 days per year. In the higher mountains and the higher

valleys in Nevada and extreme southwestern Utah, the freezefree period typically is about 150 to 180 days per year. In the

highest mountains, it is as short as 160 days per year.

Death Valley National Park is considered one of the hottest

and driest areas in the Western Hemisphere. The average annual

precipitation in the park is 1.96 inches (49.8 millimeters), and

the summer air temperatures can be as high as 134 degrees F

(56.7 degrees C).
of the United States 87

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 20.1%; ground water, 12.2%

Livestock—surface water, 2.0%; ground water, 0.1%

Irrigation—surface water, 62.1%; ground water, 1.1%

Other—surface water, 1.9%; ground water, 0.4%

The total withdrawals average 2,565 million gallons per day

(9,710 million liters per day). About 14 percent is from ground

water sources, and 86 percent is from surface water sources. The

low amount of rainfall in this area maintains the desert

vegetation, but water is scarce. The public water supply and

irrigation water for agriculture are obtained almost entirely

from the Colorado and Mojave Rivers. This water is of good

quality and is suitable for most uses. Some irrigation water is

obtained from large springs in Nevada that typically contain

about 1,000 parts per million (milligrams per liter) total

dissolved solids.

Ground water is the only water available in Death Valley. In

this water, concentrations of total dissolved solids are about 500

parts per million (milligrams per liter) and chloride levels are

fairly high. Some public supply, domestic use, and irrigation

water is obtained from wells in Nevada and in California.

Mountain ranges tend to separate ground water basins (valley

fill deposits) in the Mojave Desert. The median value of total

dissolved solids is 375 parts per million (milligrams per liter).

Total dissolved solids are lowest at the outer edges of the

basins, where recharge occurs from surface runoff in the

mountains. A level of total dissolved solids of more than 4,000

parts per million (milligrams per liter) is not uncommon under

playa lakes in the low parts of the basins.

Ground water in the Las Vegas Valley basin fill aquifer

typically exceeds 500 parts per million (milligrams per liter)

total dissolved solids. Ground water in the southeast corner of

the valley has a total dissolved solids content of more than

2,000 parts per million (milligrams per liter) because of

deposits of gypsum and evaporites. This water also contains

very high levels of arsenic, boron, and fluoride from natural

sources. These contaminants exceed State and Federal

standards for drinking water. All of the ground water in this

MLRA is very hard.

Soils

The dominant soil orders in this MLRA are Aridisols and

Entisols. The soils in the area dominantly have a thermic soil

temperature regime, an aridic soil moisture regime, and mixed

or carbonatic mineralogy. They generally are well drained to

excessively drained, loamy-skeletal or sandy-skeletal, and

shallow to very deep. Torriorthents formed in alluvium on fan

pediments, alluvial fans, fan aprons, and flood plains (Arizo,

Carrizo, Hesperia, and Yermo series) and in residuum and

colluvium on limestone and dolomite hills and mountains (St.

Thomas series), on volcanic hills and mountains (Sunrock

series), and on granite hills and mountains (Dalvord and

Goldroad series). Torripsamments (Cajon series), Haplocalcids

(Gunsight, Huevi, Tonopah, and Weiser series), and Petrocalcids

(Bard, Cave, and Mormon Mesa series) formed in alluvium on

alluvial fans, fan aprons, mesas, and terraces.

Biological Resources

This area supports thin stands of desert vegetation.

Creosotebush, white bursage, Joshua-tree, juniper, yucca,

cactus, and Mormon tea are the major species. Numerous

annual forbs and grasses grow during years of favorable

moisture. Saltbush, saltgrass, alkali sacaton, and iodinebush

grow on alkali flats. Indian ricegrass, Joshua-tree, desert

needlegrass, and galleta grow on sandy soils.

Some of the major wildlife species in this area are antelope,

coyote, kit fox, jackrabbit, cottontail, squirrel, roadrunner,

Gambel’s quail, mourning dove, gopher snake, sidewinder, and

rattlesnake. Some water bodies contain various species of

pupfish. The desert tortoise, a threatened species, is in parts of

this MLRA.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—private, 13%; Federal, 65%

Forest—Federal, 2%

Urban development—private, 2%; Federal, 2%

Water—private, 1%; Federal, 2%

Other—private, 5%; Federal, 8%

About four-fifths of this area is federally owned. Much of the

remainder is owned by local governments. Most of the land has

a cover of desert vegetation. The area is used only locally for

grazing because of low forage production and the lack of water

for livestock. On sites intensively used for recreation,

especially where motorcycles and off-road vehicles are driven,

the hazards of wind erosion and water erosion are severe. In

Utah, where an adequate water supply is available, much of the

land that was irrigated cropland or hayland, as well as some of

the adjacent rangeland, is undergoing urbanization.

The major soil resource concerns on rangeland are the

productivity and sustainability of the soils and the hazards of

wind erosion and water erosion. Compaction, soil tilth,

management of soil moisture, and wind erosion are the major

soil resource concerns on irrigated cropland. In urbanized areas

and irrigated fields, differential settling resulting from the

content of gypsum in the soils is a management concern,

particularly in the area around St. George, Utah.

Conservation practices on irrigated cropland generally

include irrigation system improvement, irrigation water

management, nutrient management, and pest management.
88 Major Land Resource Areas

31—Lower Colorado Desert

This area (shown in fig. 31-1) is in California (93 percent)

and Arizona (7 percent). It makes up about 11,615 square miles

(30,100 square kilometers). The most prominent towns in the

area are Blythe, El Centro, Indio, and Oasis, California.

Interstates 8 and 10 cross the southern and central parts of this

area, respectively. Numerous national wilderness areas and

State recreation areas and a small part of the Joshua Tree

National Monument are in this MLRA. The El Centro Naval Air

Facility is in the part of this area in California. The area also

includes the Cabezon, Augustine, Torres-Martinez, and Fort

Yuma Indian Reservations in California and the Cocopah

Indian Reservation in Arizona. The Colorado River Indian

Reservation straddles the State line between California and

Arizona in this MLRA.

Physiography

This area is in the Basin and Range Province of the

Intermontane Plateaus. It is mostly in the Salton Trough

Section, but small portions of the area are in the Sonoran Desert

and Mexican Highland Sections. This MLRA is west of the

Conservation practices on rangeland include prescribed

grazing, development of watering facilities, and erosion

control. 

Figure 31-1: Location of MLRA 31 in Land Resource Region D.

Colorado River, is east of the Peninsular Ranges, and is

bordered on the north by a gradual ecotone around 34 to 35

degrees north latitude into the Mojave Desert. To the south, it

extends into Baja California Norte in Mexico. Landforms

consist of mountains, alluvial fans, alluvial fan remnants, and

alluvial valleys, including active drainages and fluvial terraces,

and internally drained basins, including dry lakes and lake

terraces. The area is subdivided into the Imperial Valley, where

intermittent streams, canals, and the New and Alamo Rivers

drain into the Salton Sea; the lower Colorado River Valley; and

smaller internally drained basins that terminate at playas,

including those in the Chuckawalla Valley. The terminal sink

basin in the Imperial Valley was occupied during the Pleistocene

by Lake Cahuilla and is presently occupied by the Salton Sea,

which was accidentally created in 1905 when the Colorado River

passed uncontrolled through an irrigation diversion.

Elevation ranges from approximately 275 feet below sea

level (-84 meters) at the lowest point of the Salton Trough

below the southern part of the Salton Sea to 1,650 feet above

sea level (505 meters) along low mountain ranges trending

northwest and southeast within this area. The elevation in some

mountain ranges exceeds 1,650 feet (505 meters), but higher

elevations are more typical of MLRAs 30 and 29.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Southern Mojave-Salton Sea (1810), 68 percent, and Lower

Colorado (1503), 32 percent.

Geology

Most of this area is underlain by Quaternary (Pleistocene to

Recent) alluvial fan deposits and by alluvial and lacustrine

deposits beneath the valley floors. Recent alluvial fans and

alluvial fan remnants typically grade from boulder-strewn

deposits and coarse desert pavement near the fan apex to finer

grained sands, silts, and clays at the distal ends, where they

interfinger with valley floor alluvium and basin fill. The lowest

elevations are variably underlain by silty lacustrine and playa

deposits of Pleistocene Lake Cahuilla, evaporitic playa deposits

in internally drained basins, and relatively coarse grained

alluvium along the Colorado River. Eolian deposits are

typically along the downwind fringes of the playas. The

aerially extensive Algodones dunes of the Sand Hills are along

the southeast edge of the Imperial Valley.

Upland areas to the west are principally underlain by

Mesozoic granites and pre-Cenozoic metamorphics of the

Southern California Batholith, which form the Peninsular

Ranges of California and Mexico. Portions of the lower uplands

to the west are alternately underlain by moderately

consolidated to loosely consolidated sedimentary deposits of

Tertiary age. Uplands east of the Imperial Valley are variably

underlain by Precambrian to Mesozoic igneous and

metamorphic rocks and by Tertiary volcanics and sedimentary

rocks.
of the United States 89

The tectonic setting of this MLRA is dominated by oblique

right-lateral strike slip motion along the South Branch San

Andreas, Imperial Valley, and San Jacinto Fault Zones. Aligned

from northwest to southeast, these zones pass through the

western, south-central, and northeastern parts of the Imperial

Valley, respectively.

Climate

The Colorado Desert has the lowest annual precipitation and

the highest temperature in North America. The average annual

precipitation is 3 to 22 inches (75 to 560 millimeters) and

displays high temporal and spatial variability. Precipitation is

bimodal in nature. The winter precipitation is from Pacific

storms that are frontal in nature. The summer precipitation is

from subtropical convection storms coming from the south. The

winter precipitation decreases from west to east, whereas the

summer rainfall decreases from east to west. The summer (July

through September) precipitation makes up 20 to 35 percent of

the total annual precipitation. It typically occurs as highintensity storms that produce high runoff and contribute little

to the soil moisture supply. The average annual temperature is

53 to 74 degrees F (12 to 24 degrees C). The freeze-free period

averages 290 days and ranges from 220 to 365 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 2.0%; ground water, 0.0%

Irrigation—surface water, 90.5%; ground water, 2.3%

Other—surface water, 5.1%; ground water, 0.1%

The total withdrawals average 1,080 million gallons per day

(4,105 million liters per day). About 2 percent is from ground

water sources, and 98 percent is from surface water sources. The

low rainfall in this area maintains the desert vegetation, but

water is scarce. The public water supply and irrigation water for

agriculture are obtained almost entirely from the Colorado

River, but wells in river alluvium provide some irrigation

water locally. The river water is of good quality and is

suitable for most uses. It has 770 parts per million (milligrams

per liter) total dissolved solids. This is equivalent to slightly

more than 1 ton (910 kilograms) of salts per 325,850 gallons

(1,233,340 liters) of water. The solids are dominantly neutral

calcium salts.

Soils

The dominant soil orders in this MLRA are Entisols and

Aridisols. The soils in the area have a hyperthermic soil

temperature regime and an extremely aridic soil moisture

regime. They generally are very deep, well drained to

excessively drained, and coarse textured to fine textured. Level

and nearly level, coarse textured to fine textured Torrifluvents

formed in recent lacustrine sediments from igneous sources

(Coachella series) or from mixed sources (Imperial series) in

basins; in alluvium from mixed sources (Glenbar series) on

flood plains and stream terraces; or in mixed alluvium (Antho,

Holtville, Indio, and Ripley series) on flood plains and alluvial

fans. Nearly level to gently sloping, coarse textured

Torriorthents (Carrizo series) and coarse textured

Torripsamments (Carsitas, Lagunita, Myoma, and Rositas

series) formed in recent alluvium on alluvial fans. Nearly level,

moderately fine textured Haplargids (Orita series) formed in

recent alluvium from mixed sources on alluvial fan remnants.

Nearly level, coarse textured Haplocalcids (Aco series) formed

in recent alluvium from mixed sources on stream terraces.

Biological Resources

Plant growth in this area is typically both open and simple,

reflecting the intense competition between plants for the scarce

water resource. A large number of Colorado Desert plants are in

the Mojave and Sonoran Deserts. The most widespread

vegetative type in the area is dominated by creosotebush and

white bursage. This type is typically on alluvial fan piedmonts,

reaching the greatest development on coarse textured,

somewhat excessively drained or well drained soils. Other

common species include ocotillo, brittlebush, and white ratany.

Important perennial grasses include big galleta, California

threeawn, and fluffgrass. The most common species along large

drainageways are frost-sensitive species, such as smoketree,

desert ironwood, desert lavender, blue paloverde, and catclaw

acacia. Several species occur only within this MLRA, including

California lotebush, California indigobush, desert apricot, rose

sage, and Vasey sage. The California fan palm, an endemic

species, occurs only in isolated microhabitats.

Some of the major wildlife species of this area include desert

bighorn sheep, southern mule deer, coyote, bobcat, and blacktailed jackrabbit. Rare animals include desert pupfish, desert

tortoise, Coachella Valley fringe-toed lizard, and Le Conte’s

thrasher.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 7%

Grassland—private, 1%; Federal, 47%

Urban development—private, 3%

Water—private, 4%

Other—private, 26%; Federal, 12%

About three-fifths of the area is federally owned. Intensive

agriculture is practiced in the Imperial Valley, in the Coachella
90 Major Land Resource Areas

Valley, and on terraces along the Colorado River. All

agricultural crops are grown under irrigation. Cotton, alfalfa

hay, small grain, and row crops, such as lettuce, melons, onions,

sweet corn, grain sorghum, squash, and sugar beets, are

extensively grown in the Imperial Valley and on the terraces

along the Colorado River. The Coachella Valley produces early

table grapes, citrus fruit, winter vegetables, and dates, among

other specialty crops. Irrigated, warm-season pasture grasses are

being planted in the Imperial and Palo Verde Valleys, especially

on fine textured soils affected by high salinity. Feedlots are a

significant land use in the Imperial Valley. Winter pasture for

sheep is provided by alfalfa and the residue of many other

crops. Rangeland is primarily ephemeral. During favorable

years, an adequate volume of forage to accommodate livestock

grazing for a short period may be produced. Grazing strategies

should be opportunistic and should be influenced by the

environmental sensitivity of the area.

The major soil resource management concerns are irrigationinduced water erosion, wind erosion, the content of organic

matter in the soils, the productivity and sustainability of the

soils, irrigation water management, and maintenance of a

favorable salinity status in the root zone. Wind abrasion is a

critical problem on coarse textured soils during periods of crop

establishment.

Conservation practices on cropland generally include crop

rotations and minimum tillage. Also, crop residue management

and windbreaks help to control wind abrasion. The amount of

rainfall is too low to leach salts from the soils, so all leaching

must be accomplished through the use of irrigation water. 

Figure 32-1: Location of MLRA 32 in Land Resource Region D.

32—Northern Intermountain Desertic

Basins

This area (shown in fig. 32-1) is in Wyoming (96 percent)

and Montana (4 percent). It makes up about 8,910 square

miles (23,080 square kilometers). The towns of Riverton,

Thermopolis, Worland, and Powell, Wyoming, are in this

MLRA. U.S. Highways 14, 20, 26, and 310 cross this area.

This MLRA has numerous wilderness study areas. The

Wind River Indian Reservation is in the southern third of

this area.

Physiography

The northern two-thirds of this MLRA is in the Bighorn

Basin. It is in the Middle Rocky Mountains Province of the

Rocky Mountain System. All of this part of the MLRA is an

elevated, dissected basin surrounded by mountain ranges to the

east, west, and south. The Owl Creek and Bridger Mountains

separate the northern two-thirds of the MLRA from the southern

third. The southern third is in the Wind River Basin, an

elevated, dissected plain with mountains to the north, west, and

south. This part of the MLRA is in the Wyoming Basin

Province of the Rocky Mountain System. Some isolated low

mountains are in each part of this MLRA. Elevation ranges

from 3,900 to 5,900 feet (1,190 to 1,800 meters). Piedmont

plains and pediments slope from the mountains to the stream

terraces of the Wind River and Bighorn Basins. In some areas

the plains are eroded to the clay shale bedrock, and there are

areas of badlands.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Bighorn (1008), 93 percent, and Upper Yellowstone (1007), 7

percent. The Beaver and Wind Rivers join to form the Bighorn

River in the southern third of this area. The Bighorn River cuts

through the Owl Creek Mountains and continues into the

northern part of this MLRA. The Shoshone and Greybull Rivers

join the Bighorn River in the northern part of the area. Clark’s

Fork of the Yellowstone River exits the area in the northwest

corner.

Geology

This area is in a syncline between anticlinal mountain

ranges. The surface is covered with old deposits of sand and
of the United States 91

gravel washed into the basin by the streams and rivers draining

the surrounding mountains. The present-day rivers and streams

have excavated the old pediment surfaces, forming terraces.

Alluvial fan deposits grade into the valley fill pediments. The

igneous and sedimentary rocks exposed in the adjacent

mountains occur beneath the surface of the Bighorn Basin.

Tertiary sandstones and shales are exposed where the overlying

alluvium has been eroded away. Older sandstones, shales, and

carbonate rocks are exposed as steeply dipping beds on the

mountainsides. The core of most of the mountain ranges is

granite. The granite may be exposed at the higher elevations

along the margin of the basins.

Climate

The average annual precipitation in most parts of the basins

is 6 to 12 inches (150 to 305 millimeters). It is as high as 22

inches (560 millimeters) in the higher areas within the basins.

The maximum precipitation from frontal storms occurs in

spring and fall. The surrounding mountain ranges block many

of the regional precipitation events. The average annual

temperature is 39 to 48 degrees F (4 to 9 degrees C). The

temperature can vary widely within short periods because of

drainage of cooler mountain air into the basins. The freeze-free

period averages 145 days and ranges from 110 to 180 days.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 0.0%; ground water, 0.0%

Irrigation—surface water, 99.8%; ground water, 0.0%

Other—surface water, 0.2%; ground water, 0.0%

The total withdrawals average 2,505 million gallons per day

(9,480 million liters per day). Almost 100 percent is from

surface water sources. The low and erratic precipitation

provides only a small amount of the surface water used in this

area. The Wind and Bighorn Rivers and their tributaries bring

good-quality irrigation water into the area from the bordering

mountains. A few reservoirs store water, but most of the surface

water used is diverted directly from the streams. Supplies

become scarce late in the growing season, from July through

September.

Deep artesian wells provide some water for irrigation on the

eastern side of the Bighorn Basin. These wells are finished

either in sandstone units in the Dakota Formation or in the

carbonate rocks of the Madison Group. The well water is very

hard, but the median level of total dissolved solids is generally

less than 300 parts per million (milligrams per liter). Ground

water occurs in the alluvial basin fill deposits near the surface.

This water can be soft to very hard and typically contains total

dissolved solids of more than 1,000 parts per million

(milligrams per liter). This ground water is not used in the area.

Soils

The dominant soil orders in this MLRA are Entisols and

Aridisols. The soils in the area dominantly have a mesic soil

temperature regime, an aridic soil moisture regime, and mixed

mineralogy. They generally are shallow to very deep, well

drained, and loamy. Torriorthents formed in alluvium on

alluvial fans and flood plains (Apron and Kishona series) and in

residuum and colluvium on hills and piedmonts (Chipeta,

Greybull, Persayo, Shingle, and Worland series). Torrifluvents

(Lostwells and Youngston series) and Natrargids (Uffens series)

formed in alluvium on flood plains, alluvial fans, and stream

terraces. Ustorthents (Spearfish series) formed in residuum and

colluvium on hills.

Biological Resources

This area supports shrub-grass vegetation. Big sagebrush,

Gardner’s saltbush, rhizomatous wheatgrasses, Indian ricegrass,

and needleandthread are the dominant species. Black sage,

Gardner’s saltbush, and bluebunch wheatgrass are common on

shallow soils in the uplands.

Some of the major wildlife species in this area are antelope,

coyote, jackrabbit, and sage grouse.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 6%

Grassland—private, 42%; Federal, 47%

Urban development—private, 2%

Water—private, 1%

Other—private, 1%; Federal, 1%

Nearly one-half of this area is federally owned. The rest is in

farms and ranches. Most of the land is used for grazing. The

rangeland consists of desert shrubs and short grasses. About 5

percent of the area is irrigated. Most of the irrigated areas are

used for alfalfa and other feed crops, but dry beans, malt barley,

sugar beets, and corn are important cash crops.

The major soil resource concerns are water erosion, water

quality, rangeland health, and soil quality. Conservation

practices on cropland generally include irrigation water

management and installation of water-conserving irrigation

systems. 
92 Major Land Resource Areas

Figure 34A-1: Location of MLRA 34A in Land Resource Region D.

34A—Cool Central Desertic Basins and

Plateaus

This area (shown in fig. 34A-1) is in Wyoming (85 percent),

Colorado (13 percent), and Utah (2 percent). It makes up about

33,005 square miles (85,525 square kilometers). The cities of

Laramie, Pinedale, Rawlins, and Rock Springs, Wyoming, and

Craig and Meeker, Colorado, are in this MLRA. Interstate 80

bisects the northern part of the MLRA.

Physiography

About 85 percent of this area is in the Wyoming Basin

Province of the Rocky Mountain System, 5 percent is in the

Middle Rocky Mountains Province of the Rocky Mountain

System, and 10 percent is in the Uinta Basin Section of the

Colorado Plateaus Province of the Intermontane Plateaus. The

part of the area in the Uinta Basin Section is in Colorado. The

Wyoming Basin is bounded on most sides by mountains. The

Owl Creek Mountains, the Big Horn Mountains, and the Wind

River Range are to the north; the Salt Range and Wasatch

Mountains are to the west; and the Laramie and Sierra Madre

Mountains are to the east. The part of the MLRA in Colorado is

bounded on the south by the Roan Plateau, on the east by the

Elkhead Mountains, and on the west by Dinosaur National

Monument. In most of the MLRA, elevation ranges from 5,200

feet (1,585 meters) to 7,500 feet (2,285 meters). Small

mountainous areas have an elevation as high as 9,200 feet

(2,805 meters).

The extent of the Hydrologic Unit Areas (identified by fourdigit numbers) that make up this MLRA is as follows: Great

Divide-Upper Green (1404), 47 percent; North Platte (1018), 28

percent; White-Yampa (1405), 16 percent; Bighorn (1008), 6

percent; Bear (1601), 2 percent; and Powder-Tongue (1009), 1

percent. The Popo Agie, Sweetwater, Laramie, Green, and North

Platte Rivers run through the northern part of this MLRA, and

the Little Snake, Yampa, and White Rivers run through the

southern part.

Geology

This area is dominated by residual basin-floor geologic

materials. Shale and sandstone are the dominant rock types.

The Tertiary-age Bridger, Laney, Green River, Wasatch, Wind

River, and Browns Park Formations dominate the MLRA.

Cretaceous-age formations occur as small areas throughout the

MLRA. The dominant Cretaceous formations are the Lewis and

Lance Formations and the members of the Mesa Verde Group.

Quaternary alluvial and eolian deposits occur throughout the

MLRA. Glacial deposits occur primarily on outwash terraces in

the vicinity of Pinedale, Wyoming. The small mountain ranges

in this MLRA are made up of Precambrian igneous and

metamorphic rocks.

Climate

The average annual precipitation generally is 7 to 12 inches

(180 to 305 millimeters), but it ranges from 7 to 32 inches (180

to 815 millimeters). Much of the precipitation occurs as snow

from October through April and as rain from May through

September. These precipitation events occur as a result of cold

fronts moving through the area. Occasional convective

thunderstorms produce small amounts of rain during the period

June through September. The driest period is usually June

through August. The average annual temperature generally is

40 to 44 degrees F (5 to 7 degrees C), but it ranges from 33 to

47 degrees F (0 to 8 degrees C). The freeze-free period averages

105 days and ranges from 45 to 160 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.3%; ground water, 0.3%

Livestock—surface water, 0.2%; ground water, 0.2%

Irrigation—surface water, 89.7%; ground water, 5.1%

Other—surface water, 2.8%; ground water, 1.4%

The total withdrawals average 2,590 million gallons per day

(9,805 million liters per day). About 7 percent is from ground

water sources, and 93 percent is from surface water sources.
of the United States 93

Water is scarce in much of the MLRA. Irrigation water is

available, however, along the few rivers that bring water into the

area from the adjoining mountains. Numerous reservoirs store

snowmelt runoff for later use in the growing season. The surface

water is of good quality. It is suitable for almost all uses with

minimal treatment.

Ground water supplies are meager and little developed in

much of this area. A large area of irrigated cropland is along the

Bear River, in the northwest corner of the part of this MLRA in

Utah. Ground water from the unconsolidated valley fill is

pumped for irrigation. This water typically contains less than

1,000 parts per million (milligrams per liter) total dissolved

solids and is suitable for almost all uses.

Two aquifers are in the part of this area in Wyoming. One is a

sand-and-gravel aquifer that is equivalent to the High Plains

(Ogallala) aquifer farther east. Water from the sand-and-gravel

aquifer contains less than 500 parts per million total dissolved

solids (milligrams per liter) and is moderately hard. It is used for

public and domestic supply, livestock, and irrigation. Water

also occurs at greater depths in the structural basin aquifer,

which is the most extensive and widely used aquifer in this

area. It has lenticular beds of sandstone, coal, and shale that can

exceed 5,000 feet in thickness. Because of a median level of

1,100 parts per million total dissolved solids (milligrams per

liter), the water from this aquifer generally is unsuitable for

public supplies. The water is used for domestic supply,

livestock, and some irrigation.

Soils

The dominant soil orders in this MLRA are Aridisols and

Entisols. Some representative suborders are Argids, Cambids,

Calcids, Orthents, Fluvents, and Psamments. The most

extensive and representative great groups are Haplargids

(Forelle, Ryan Park, Ryark, and Maysprings series),

Haplocambids (Poposhia, Kemmerer, and Chaperton series),

Haplocalcids (Fiveoh, Langspring, and Tieside series),

Torriorthents (Moyerson, Blazon, and Haterton series),

Natrargids (Tisworth and Tismid series), Calciargids (Rock

River and Cushool series), Torrifluvents (Cowestglen and

Battlement series), and Torripsamments (Maybell and Kandaly

series).

The dominant soil temperature regime is frigid, and the

dominant soil moisture regime is aridic. The soils receiving less

than 8 inches (205 millimeters) of precipitation annually have

an aridic soil moisture regime. The soils receiving 8 to 14

inches (205 to 355 millimeters) have an aridic soil moisture

regime that borders on ustic. The soils receiving 14 to 16

inches (355 to 405 millimeters) have an ustic soil moisture

regime that borders on aridic. On the lower slopes of the minor

mountain ranges, the soils that receive 16 to 20 inches (405 to

510 millimeters) of precipitation generally have a frigid soil

temperature regime and an ustic soil moisture regime. The soils

at the highest elevations in the small mountain ranges have a

cryic soil temperature regime and a udic soil moisture regime

that borders on ustic. Some soils with a mesic soil temperature

regime occur at the lowest elevations in the southern part of the

MLRA. Soils with mixed or smectitic mineralogy are dominant.

Many of the soils are shallow or moderately deep to shale or

sandstone bedrock. Many formed in slope alluvium or

residuum derived from shale or sandstone. Soils that formed in

stream- or river-deposited alluvium are near the major

waterways. Most of the soils are well drained. Most are

calcareous.

Biological Resources

The kind of vegetation varies from one precipitation zone to

another in this MLRA.

The salt desert zone occurs in small areas receiving less than

8 inches (205 millimeters) of annual precipitation. The

representative plant species are Gardner’s saltbush, mat

saltbush, greasewood, shadscale, bud sagebrush, winterfat,

Indian ricegrass, and western wheatgrass. Wyoming big

sagebrush may occur but only as a few widely spaced plants.

A semi-desert grass-shrub zone, the largest in the MLRA, is

characterized by a vast sagebrush steppe. This zone occurs in

the areas receiving 8 to 16 inches (205 to 405 millimeters) of

annual precipitation. The representative vegetation includes

Wyoming big sagebrush, early sagebrush, antelope bitterbrush,

bluebunch wheatgrass, western wheatgrass, prairie junegrass,

needleandthread, and Indian ricegrass. Utah juniper may occur

in small areas. Cottonwood and willows grow in riparian zones

along the major perennial streams and rivers.

A foothill-mountain zone in Wyoming is in the narrow

mountain ranges that receive more than 16 inches (405

millimeters) of annual precipitation. The vegetation on these

ranges includes ponderosa pine, limber pine, lodgepole pine,

and Engelmann spruce and an understory of big sagebrush,

Oregon-grape, Saskatoon serviceberry, antelope bitterbrush,

bluebunch wheatgrass, and Idaho fescue.

Another small zone in this MLRA occurs on the high plains

grasslands near Laramie, Wyoming. This zone is dominated by

cool-season grasses, such as bluebunch wheatgrass, green

needlegrass, muttongrass, and western wheatgrass. Big

sagebrush is conspicuously absent in this area.

A lower foothill-mountain zone along the southern boundary

of Wyoming and in Colorado occurs on the higher hills and

mesas receiving more than 12 inches (305 millimeters) of

annual precipitation. This zone is characterized by forested

areas of Utah juniper with lesser amounts of pinyon pine and

with an understory of Gambel oak, Wyoming big sagebrush,

mountain mahogany, muttongrass, needleandthread, prairie

junegrass, and Indian ricegrass.

Some of the major wildlife species in this MLRA are whitetailed prairie dog, white-tailed jackrabbit, desert cottontail

rabbit, coyote, red fox, badger, pronghorn, mule deer, elk, sage

grouse, golden eagle, bald eagle, screech owl, common raven,
94 Major Land Resource Areas

34B—Warm Central Desertic Basins and

Plateaus

This area (shown in fig. 34B-1) is in Utah (70 percent) and

Colorado (30 percent). It makes up about 12,850 square miles

(33,290 square kilometers). The cities of Vernal, Roosevelt,

Price, and Duchesne, Utah, and Grand Junction, Delta, and

Montrose, Colorado, are in this MLRA. U.S. Highway 40

bisects the northern part of the area, and Interstate 70 bisects

the southern part. The Uintah and Ouray Indian Reservation

and the western end of Dinosaur National Monument are in this

MLRA.

sage sparrow, Brewer’s sparrow, western rattlesnake, and bull

snake.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 2%

Grassland—private, 27%; Federal, 67%

Forest—Federal, 1%

Urban development—private, 1%

Other—private, 1%; Federal, 1%

A little more than two-thirds of this area is federally owned.

The rest is in private ranches. Most of the land is used for

grazing by sheep and cattle. Hunting also is an important land

use. The rangeland consists of shrubs and cool-season grasses.

About 2 percent of the area is cropland. Areas of irrigated hay

and pasture occur mostly along the few large rivers or streams.

Nonirrigated small grain crops are grown in small areas near

Craig and Meeker, Colorado, where the annual precipitation is

more than 13 inches (330 millimeters), the freeze-free period is

more than 75 days, the soils commonly are deep, and grainmarketing facilities are nearby.

The major soil resource concerns are erosion, salinity, and

water quality in streams and rivers. The availability of water for

crops and livestock limits agricultural production. The main

management concerns on rangeland are wind erosion, gully

erosion, invasive species, and declining rangeland health. The

main concerns on cropland are salinization and declining water

tables.

Conservation practices on rangeland generally include

erosion control, fencing, development of watering facilities,

brush management, rangeland seeding, and proper grazing

management. The conservation practices that are important on

cropland are those that reduce the hazard of erosion and

improve the efficiency of irrigation water use. Conservation

practices on hayland and pasture are improvement of the

efficiency of irrigation systems, irrigation water management,

and forage harvest management. 

Figure 34B-1: Location of MLRA 34B in Land Resource Region D.

Physiography

This area is in the Canyon Lands (60 percent) and Uinta

Basin (35 percent) Sections of the Colorado Plateaus Province

of the Intermontane Plateaus. A small part of the area is in the

High Plateaus of Utah Section of the Colorado Plateaus

Province of the Intermontane Plateaus. Another small part is in

the Middle Rocky Mountains Province of the Rocky Mountain

System. This MLRA consists of broad intermountain basins

bounded by plateaus and steep escarpments. The northern part

of the MLRA occurs in the Uinta Basin Section, which is

bounded by the Uinta Mountains to the north, the Wasatch

Range to the west, the Roan Plateau to the south, and the Rabbit

Hills to the east. The southern part of the MLRA occurs in the

northern third of the Canyon Lands Section. This section is

bounded by the Roan Plateau to the north, the Wasatch Plateau

to the west, the southern end of the San Rafael Swell to the

south, and the western slope of the Rocky Mountains to the

east. Elevation ranges from 4,100 feet (1,250 meters) near Green

River, Utah, to 7,500 feet (2,285 meters) at the base of the

Wasatch Range and the Roan Plateau.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Lower Green (1406), 51 percent; White-Yampa (1405), 18

percent; Colorado Headwaters (1401), 11 percent; Gunnison

(1402), 9 percent; Upper Colorado-Dirty Devil (1407), 6

percent; and Upper Colorado-Dolores (1403), 5 percent. The
of the United States 95

water sources, and 91 percent is from surface water sources.

Precipitation is sparse in this area. There is a significant area of

irrigated hayland and cropland in the Duchesne, Price, and San

Rafael basins in the part of this area in Utah. The surface water

is of good quality and is pumped or diverted from the rivers for

irrigation. Water-supply concerns in these basins include

Native American water rights and coal and oil-shale

development. The Upper Colorado, White, and Gunnison

Rivers in Colorado are used to irrigate hay meadows, orchards,

and cropland. The river water is generally of good quality,

except for short reaches that are contaminated with trace

elements and metals from mining and naturally occurring

sources. Water rights, salinity control, and water transfers to the

eastern side of the Continental Divide are water-supply

concerns in Colorado.

There are two sources of ground water in this MLRA. One is

unconsolidated valley fill in the northern part of the area, and

the second is a sandstone aquifer in the southern part. Dakota

Sandstone, the Morrison Formation, and Entrada Sandstone are

the Colorado equivalent of the sandstone aquifer in Utah. Water

from the unconsolidated valley fill aquifer is of good quality and

is used for both public supply and irrigation. Water from the

sandstone aquifer also is used for public supply and irrigation, but

its quality varies considerably. The ground water near recharge

zones has the best quality. Deeper water may be saline.

Soils

The dominant soil orders in this MLRA are Aridisols and

Entisols. Mollisols occur at the higher elevations, particularly in

the northern part of the MLRA. Some of the most extensive and

representative great groups are Torriorthents (Chipeta, Persayo,

Cadrina, Killpack, and Gerst series), Haplocalcids (Walknolls,

Abracon, Avalon, and Shalako series), Haplocambids (Gilston,

Bullpen, and Sagers series), Calciargids (Solirec, Mesa, and

Progresso series), Natrargids (Motto and Uffens series), Argiustolls

(Cortyzack series), Torrifluvents (Ravola and Green River series),

and Haplustolls (Moonset series).

The dominant soil temperature regime is mesic, and the

dominant soil moisture regime is aridic. The soils receiving less

than 8 inches (205 millimeters) of precipitation annually have

an aridic soil moisture regime. The soils receiving 8 to 12

inches (205 to 305 millimeters) have an aridic soil moisture

regime that borders on ustic. The soils receiving 12 to 16

inches (305 to 405 millimeters) generally have an ustic soil

moisture regime that borders on aridic. Some soils with a frigid

soil temperature regime and an ustic soil moisture regime occur

at the highest elevations in the northern part of the MLRA. The

dominant soil mineralogy is mixed. The soils that formed in

material weathered from Mancos Shale tend to have active or

semiactive clay activity classes. Most of the soils formed in

slope alluvium or residuum derived from shale or sandstone.

Soils that formed in alluvium occur near the major waterways,

and soils that formed in colluvium occur generally on slopes of

Colorado, Green, Gunnison, Price, and Uncompahgre Rivers run

through the southern part of this MLRA. The Duchesne, Green,

Strawberry, and White Rivers run through the northern part.

Geology

Most of this area is covered by residual basin-floor materials

and materials washed in from the surrounding mountains and

plateaus. Shale and sandstone are the dominant rock types. The

Tertiary-age Green River, Uinta, and Duchesne Formations

dominate the northern part of the MLRA. The southern part is

dominated by Cretaceous-age materials with lesser amounts of

Jurassic and Triassic materials. The dominant Cretaceous

formations are Mancos Shale, Dakota Sandstone, and the

members of the Mesa Verde Group. The dominant Jurassic

formations are the Morrison, Entrada, and Navajo. The

dominant Triassic formations are the Chinle and Moenkopi.

Quaternary alluvial, eolian, and glacial deposits occur in both

parts of the MLRA. Glacial deposits on outwash terraces occur

primarily along the Uncompahgre and Gunnison Rivers in

Colorado and on outwash terraces from the Uinta Mountains

north of Duchesne, Utah. Permian Kaibab Limestone occurs on

the crest of the San Rafael Swell, an Eocene anticline west of

Green River, Utah, that is about 100 miles long from north to

south and about 40 miles wide. Tertiary-age granodiorite

intrusives occur off the southwest tip of the San Rafael Swell.

Climate

The average annual precipitation in most of this area ranges

from 6 to 10 inches (150 to 255 millimeters). A small part of

this area receives as much as 24 inches of annual precipitation.

Much of the precipitation occurs as high-intensity, convective

thunderstorms during the period July through September. May

and June are usually the drier months. Precipitation is more

evenly distributed throughout the year in the northern part of

the MLRA than in the southern part, where there is a significant

peak in late summer. The northern part of the MLRA receives

more precipitation as snow during winter than the southern

part. The average annual temperature ranges from 41 to 54

degrees F (5 to 12 degrees C). The freeze-free period averages

170 days and ranges from 110 to 235 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 4.0%; ground water, 0.3%

Livestock—surface water, 0.7%; ground water, 0.0%

Irrigation—surface water, 85.1%; ground water, 8.7%

Other—surface water, 1.0%; ground water, 0.3%

The total withdrawals average 1,440 million gallons per day

(5,450 million liters per day). About 9 percent is from ground
96 Major Land Resource Areas

more than 35 percent. Many of the soils are shallow or moderately

deep to shale or sandstone bedrock. Most are well drained. Most

are calcareous. The soils at the lower elevations generally have

significant amounts of calcium carbonate, salts, and gypsum.

Biological Resources

This area has three major land resource units. These are the

desert-salt desert zone, the semi-desert zone, and the uplandfoothill zone.

The largest and most dominant unit is the desert-salt desert

zone. This zone occurs at the lower elevations receiving less

than 8 inches of annual precipitation (205 millimeters). The

representative vegetation includes Castlevalley saltbush,

Gardner’s saltbush, mat saltbush, greasewood, shadscale, bud

sagebrush, winterfat, Indian ricegrass, salina wildrye, and

galleta. Cottonwood and willows grow along riparian zones.

The semi-desert zone occurs as a narrow 8- to 12-inch (205-

to 305-millimeter) precipitation band. This zone has two

vegetative subzones. The more extensive subzone includes

Wyoming big sagebrush, black sagebrush, shadscale, fourwing

saltbush, Mormon tea, Indian ricegrass, and galleta. The other

subzone occurs mostly in the area of the San Rafael Swell in

Utah. This subzone is similar to the other subzone but lacks

Wyoming big sagebrush and has more Utah juniper trees.

Wyoming big sagebrush and pinyon pine may occur but only as

a few widely scattered plants.

The upland-foothill zone occurs as a 12- to 16-inch (305- to

405-millimeter) precipitation band. Utah juniper and pinyon

pine forests are dominant in this zone. The representative

vegetation includes Utah juniper, pinyon pine, Wyoming big

sagebrush, black sagebrush, prairie junegrass, muttongrass, and

needleandthread. Gambel oak, Utah serviceberry, antelope

bitterbrush, mountain mahogany, and bluebunch wheatgrass

grow at the higher elevations.

Some of the major wildlife species in this MLRA are coyote,

kit fox, white-tailed prairie dog, white-tailed jackrabbit,

pronghorn, mule deer, elk, American kestrel, sage grouse,

turkey vulture, screech owl, mourning dove, piñon jay,

common raven, sage sparrow, bald eagle, golden eagle, western

rattlesnake, bullsnake, fence lizard, sagebrush lizard, Colorado

pike minnow, razorback sucker, bonytail, and humpback chub.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 1%

Grassland—private, 21%; Federal, 74%

Forest—Federal, 1%

Urban development—private, 1%

Other—private, 1%; Federal, 1%

About three-fourths of this area is federally owned. Most of

the area is used for recreation or livestock grazing. Different

types of surface or sprinkler irrigation are used in many of the

valleys. The major crops grown throughout the area are silage

corn, grain corn, alfalfa, and small grains. Cantaloupe and

melons are grown near Green River, Utah, and lettuce, onions,

dry beans, peppers and other small vegetable crops are grown in

the Grand Valley and Uncompahgre areas. Many tracts of

rangeland and cropland have been, and are continuing to be,

subdivided for community development.

The major soil resource concerns are salinity, sodicity,

leaching of selenium and salts into surface and ground water

supplies, irrigation-induced erosion, and subsidence resulting

from gypsum dissolution. Wind erosion is a hazard on light

textured soils during periods when annual crops are grown and

during periods of plant germination. It also is a hazard in areas

of salt-desert shrub communities. The main management

concerns on rangeland are wind erosion, gully erosion, invasive

species, and declining rangeland health. The main management

concerns in cultivated areas include salinization, declining

water tables, and inadequate supplies of irrigation water.

Conservation practices on rangeland generally include

erosion control, fencing, development of watering facilities,

brush management, rangeland seeding, and proper grazing

management. Conservation practices on cropland include

improvement of the efficiency of irrigation systems, irrigation

water management, and crop residue management.

Conservation practices on hayland and pasture include

improvement of the efficiency of irrigation systems, irrigation

water management, and forage harvest management. 

35—Colorado Plateau

This area (shown in fig. 35-1) is in Arizona (56 percent),

Utah (22 percent), New Mexico (21 percent), and Colorado (1

percent). It makes up about 71,735 square miles (185,885

square kilometers). The cities of Kingman and Winslow,

Arizona, Gallup and Grants, New Mexico, and Kanab and

Moab, Utah, are in this area. Interstate 40 connects some of

these cities, and Interstate 17 terminates in Flagstaff, Arizona,

just outside this MLRA. The Grand Canyon and Petrified Forest

National Parks and the Canyon de Chelly and Wupatki

National Monuments are in the part of this MLRA in Arizona.

The Zion, Capitol Reef, Canyonlands, and Arches National

Parks and the Grand Staircase-Escalante, Natural Bridges, and

Hovenweep National Monuments are in the part in Utah. The

Aztec Ruins, El Morro, El Malpais, and Chaco Canyon National

Monuments and the Chaco Culture National Historic Park are in

the part in New Mexico. The Dixie, Manti-La Sal, Kaibab,

Prescott, Coconino, Sitgreaves, Apache, and Cibola National

Forests are in this MLRA. “Four Corners,” the only place in

America where four State boundaries meet at one point, is in

this area. The Navajo and Hopi Nations make up a significant

portion of this MLRA in eastern Arizona, western New Mexico,

and southern Utah. Other Native American Nations in Arizona
of the United States 97

Figure 35-1: Location of MLRA 35 in Land Resource Region D.

include the Zuni, Havasupai, Hualapai, and Kaibab. The Ramah

Nation and a small part of the Acoma Nation are in the part of

this MLRA in New Mexico. Almost all of the part of this MLRA

in Colorado is in the Ute Mountain Nation.

Physiography

This area is in the Colorado Plateaus Province of the

Intermontane Plateaus. Different parts of this MLRA are in five

of the six sections within the Colorado Plateaus Province. Most

of the eastern and central parts of the MLRA are in the Navajo

Section. The second largest part, to the west of the Navajo

Section, is in the Grand Canyon Section. The northernmost part

is in the Canyon Lands Section, and the northwest corner is in

the High Plateaus of Utah Section. The southeast corner is in

the Datil Section. In general, the surface consists of gently

sloping to strongly sloping plains. Volcanic plugs that rise

abruptly above the plains, steep scarps, or deeply incised

canyons interrupt the surface of the plains. In most areas

elevation is 4,250 to 4,950 feet (1,295 to 1,510 meters). Mt.

Trumbull, on the north rim of the Grand Canyon, however,

reaches a height of 8,028 feet (2,448 meters), and Navajo

Mountain, on the Utah-Arizona State line, reaches a height of

10,388 feet (3,167 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows: Little

Colorado (1502), 34 percent; San Juan (1408), 21 percent; Lower

Colorado-Lake Mead (1501), 19 percent; Upper Colorado-Dirty

Devil (1407), 14 percent; Rio Grande-Elephant Butte (1302), 4

percent; Salt (1506), 3 percent; Upper Colorado-Dolores

(1403), 3 percent; and Lower Green (1406), 2 percent. The

Colorado River and its tributary in Arizona, the Little Colorado

River, are in this MLRA. The Glen Canyon Dam, on the

Colorado River (Lake Powell), also is in this area. The Mancos

and McElmo Rivers in Colorado are tributaries to the San Juan

River in New Mexico. Parts of the Virgin, Sevier, Escalante,

Otter, Dirty Devil, Green, and Paria Rivers are in the part of this

MLRA in Utah. Rio Puerco is in the part in New Mexico.

Geology

This area is part of the Colorado Plateau, an area that has

been structurally uplifted. Rivers flowing across the area cut

down into the bedrock as it was being uplifted, resulting in

spectacular geologic scenery. Areas of shale, sandstone,

limestone, dolomite, and volcanic rock outcrop are extensive.

Rocks representing almost the entire geologic timespan are

exposed from the bottom of the Grand Canyon up to the

present-day surface. Quaternary and Tertiary lava flows occur

on the surface in the southwest part of this area. Older flows cap

plateaus and mesas, and isolated volcanic cones and eroded

volcanic necks occur throughout the area.

Climate

The average annual precipitation is 6 to 18 inches (150 to

455 millimeters) in almost all of this area, but it is less than 5

inches (125 millimeters) in a few basins on the west edge of the

area. The highest average annual precipitation, 30 inches (760

millimeters), occurs in a few isolated mountains in southern

Utah and near the Arizona-New Mexico State line. About half of

the precipitation falls from July through September. April, May,

and June are the driest months. Most of the rainfall occurs as

high-intensity, convective thunderstorms late in summer. Light

snow falls in winter, but it does not remain on the ground very

long. The average annual temperature is 36 to 66 degrees F (2

to 19 degrees C), decreasing to the north and at the higher

elevations. The freeze-free period averages 215 days and ranges

from 105 to 320 days, decreasing in length to the north and at

the higher elevations.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.4%; ground water, 2.7%

Livestock—surface water, 5.7%; ground water, 2.0%

Irrigation—surface water, 34.9%; ground water, 12.9%

Other—surface water, 24.3%; ground water, 17.2%

The total withdrawals average 560 million gallons per day

(2,120 million liters per day). About 35 percent is from ground
98 Major Land Resource Areas

water sources, and 65 percent is from surface water sources.

Water is scarce throughout the area. Many streams and rivers are

ephemeral. The Little Colorado River drains the largest

segment of the area, but its flow is intermittent. Water is stored

in small reservoirs for irrigation purposes, but supplies are often

inadequate. Some irrigation water is obtained from erratic

streamflow. The surface water is suitable for almost all uses. A

high sediment load is the primary water-quality problem.

The San Juan River basin in the part of this area in northwest

New Mexico has the highest streamflow volume in the State. It

is one area that relies almost entirely on surface water. The

Navajo Reservoir and a few smaller reservoirs store water for

use by residents in this area. The river water is of exceptional

quality. It is suitable for a cold-water fishery. High salt and

sediment loads from ephemeral tributaries on the south side of

the basin degrade the river water.

Ground water is the primary source of drinking water in

many areas. In places some irrigation water is obtained from

deep wells. Ground water occurs in the Coconino, Navajo, and

Dakota Sandstone aquifers. It is soft to hard water and generally

contains less than 300 parts per million (milligrams per liter)

total dissolved solids in Arizona. Median levels of total

dissolved solids are closer to 1,000 parts per million

(milligrams per liter) in Utah and New Mexico. Lower levels

of total dissolved solids and fresher water occur near the

recharge zones for these consolidated sediments. Very salty

water occurs at depth and away from the recharge zones. Highly

mineralized water leaks into these aquifers from older and

younger marine sediments above and below the sandstone

aquifers.

Some irrigation water is pumped from the valley fill in the

San Juan River basin. It has a higher salt content than the river

water but otherwise is very similar in quality. Use of the valley

fill water is limited because seepage of salty water from the

adjacent rocks containing soluble salts increases the sodium

sulfate content.

Soils

The dominant soil orders in this MLRA are Alfisols,

Aridisols, Entisols, and Mollisols. The soils in the area

dominantly have a mesic soil temperature regime; an aridic soil

moisture regime or an ustic moisture regime that borders on

aridic; and carbonatic, mixed, or smectitic mineralogy. They

generally are very shallow to very deep, well drained or

somewhat excessively drained, and loamy or clayey.

Haplustalfs (Lykorly series) and Haplargids (Penistaja series)

formed in mixed eolian deposits and alluvium on mesas,

cuestas, hills, bajadas, and fan terraces. Calciargids (Millett

series) formed in alluvium on fan terraces, piedmonts, and

plains. Haplocalcids formed in mixed residuum and colluvium

on benches, hills, and ridges (Mellenthin series) and in eolian

deposits over alluvium (Winona series). Haplocambids formed

in mixed eolian deposits and alluvium on mesas, cuestas, hills,

and fan terraces (Begay series) and in alluvium on plateaus and

mesas (Epikom series). Ustorthents formed in mixed residuum

and colluvium on mesas and mountains (Menefee series) and in

mixed eolian deposits and alluvium on ridges, hills, and mesas

(Vessilla series). Torriorthents formed in mixed alluvium and

residuum (Moenkopie series) and in mixed residuum and

colluvium (Rizno series) on mesas, hills, benches, cuestas, and

plateaus. Torripsamments (Sheppard series) formed in eolian

deposits on benches, dunes, and terraces. Argiustolls (Luzena

series) formed in residuum and colluvium on mesas, hills, and

mountains.

Biological Resources

This area supports desert shrub and woodland vegetation.

At high elevations, pinyon-juniper woodland and sagebrush

have an understory of galleta, blue grama, black grama, and

western wheatgrass. Galleta grass, alkali sacaton, Indian

ricegrass, bottlebrush squirreltail, and needlegrasses intermixed

with fourwing saltbush and winterfat are at the lower

elevations. Greasewood and shadscale are part of the plant

community on salty soils. Blackbrush may be dominant at the

lower elevations.

Some of the major wildlife species in this area are elk, mule

deer, antelope, mountain lion, coyote, fox, bobcat, badger,

skunk, rabbit, prairie dog, bats, eagles, hawks, owls, crow,

woodpecker, bluebird, and swallow.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 1%

Grassland—private, 48%; Federal, 27%

Forest—private, 8%; Federal, 6%

Urban development—private, 1%

Water—private, 1%

Other—private, 7%; Federal, 1%

About one-third of this area is federally owned. About threefourths is rangeland. The rangeland is grazed by sheep and

cattle. About 1 percent of the area, along the valleys of the

major streams, is irrigated cropland. Alfalfa, small grains for

hay, and corn for silage are the chief crops. Less than one-tenth

of the area in scattered small tracts on Indian reservations is

dry-farmed. Corn is the chief crop in the dry-farmed areas. More

than one-tenth of the area is juniper and pinyon-juniper

woodland. Firewood and pinyon nuts are products of this

woodland, which also is grazed by cattle and sheep. If the areas

are overgrazed, juniper invades the grassland. Severe gullying,

overgrazing, and the lack of a dependable water supply are land

use problems. Because of the mild climate and nearby

recreational opportunities, the irrigated cropland near towns,

such as Moab and Kanab, is being converted to housing

developments.
of the United States 99

The major soil resource concerns are maintenance of the

content of organic matter in the soils, soil productivity, wind

erosion, water erosion, salinity, and sodicity. These factors and

the low rainfall result in soils that have little or no resilience

after disturbance and a very low tolerance for soil loss by

erosion.

Conservation practices on rangeland generally include brush

management, rangeland seeding, prescribed grazing, prescribed

burning, fencing, development of watering facilities, and

erosion control. Conservation practices on cropland and

hayland are crop rotation, crop residue management, minimum

tillage, nutrient and pest management, land leveling, ditch

lining, irrigation water management, soil salinity management,

and pasture and hayland management. 

Figure 36-1: Location of MLRA 36 in Land Resource Region D.

36—Southwestern Plateaus, Mesas, and

Foothills

This area (shown in fig. 36-1) is in New Mexico (58 percent),

Colorado (32 percent), and Utah (10 percent). It makes up about

23,885 square miles (61,895 square kilometers). The major

towns in the area are Cortez and Durango, Colorado; Santa Fe

and Los Alamos, New Mexico; and Monticello, Utah. Grand

Junction, Colorado, and Interstate 70 are just outside the

northern tip of this area. Interstate 25 crosses the middle of the

area, and U.S. Highway 550 runs along the southwest boundary

of the area in New Mexico. Mesa Verde National Park and the

Bandelier, Hovenweep, Natural Bridges, Yucca House, and

Colorado National Monuments are in the area. Many Indian

reservations are in this MLRA. The largest are the Southern Ute,

Ute Mountain, and Jicarilla Apache Indian Reservations. Also

in the area are the Cochiti, Jemez, Nambe, Navajo, Picuris,

Pojoaque, San Felipe, San Ildefonso, San Juan, Sandia, Santa

Ana, Santa Clara, Santa Domingo, Taos, Tesuque, and Zia

Indian Reservations.

Physiography

This area is on the Intermontane Plateaus. It is mainly in the

Canyon Lands and Navajo Sections of the Colorado Plateaus

Province, is partly in the Mexican Highland Section of the

Basin and Range Province, and extends marginally into the

Southern Rocky Mountains Province. Landforms in most areas

are controlled by the underlying sedimentary rock formations,

but fluvial landforms are in the Rio Grande rift basin at the

southeastern extent of the MLRA. Elevation commonly is

4,600 to 8,500 feet (1,400 to 2,590 meters). It generally is

highest (as much as 9,300 feet, or 2,835 meters) in areas of the

foothills and high mesas that border the Southern Rocky

Mountains. Relief generally is less than 1,500 feet (455 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows: Rio

Grande-Elephant Butte (1302), 47 percent; San Juan (1408), 32

percent; Upper Colorado-Dolores (1403), 15 percent; Gunnison

(1402), 4 percent; Colorado Headwaters (1401), 1 percent; and

Upper Colorado-Dirty Devil (1407), 1 percent. The upper

reaches of the Rio Grande and San Juan Rivers and their

tributaries are in the part of this MLRA near the Colorado and

New Mexico State lines. Rio Puerco and Rio Chama are in the

part of the MLRA in New Mexico. The Dolores and San Miguel

Rivers are in the part in Colorado, and a short reach of the

Colorado River crosses this MLRA near the Utah and Colorado

State lines.

Geology

Most of the area is characterized by generally horizontal

beds of Jurassic, Cretaceous, and Tertiary sedimentary rocks.

Representative formations are the Morrison Formation; Dakota

Sandstone, Mancos Shale, Cliff House Sandstone, and other

members of the Mesa Verde Group; the Animas Formation; and

the San Jose Formation. The sedimentary rocks have been

eroded into plateaus, mesas, hills, and canyons. Thick deposits

of eolian material of Pleistocene age mantle the top of the

mesas in some areas. Small areas of Tertiary and Quaternary

volcanic rocks, including cinder cones and lava flows, are in the

Rio Grande rift basin in New Mexico. Wide valleys in the rift

basin have accumulated deep alluvial sediments, and fan

remnants are common.
100 Major Land Resource Areas

Climate

The average annual precipitation in this area ranges from 8

to 31 inches (205 to 785 millimeters). It is dominantly 12 to 20

inches (305 to 510 millimeters). Much of the rainfall occurs as

convective storms in late summer; about 20 to 35 percent of the

total precipitation falls in July and August. This proportion

increases from north to south within the area. About 15 to 25

percent of the precipitation is snow. Snowpacks are generally

light and not persistent throughout the winter, except at the

higher elevations. The average annual temperature ranges from

37 to 56 degrees F (3 to 14 degrees C). The freeze-free period

averages 160 days and ranges from 105 to 210 days. The

shortest freeze-free periods occur in the northern part of the area

and at high elevations.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 2.1%; ground water, 3.6%

Livestock—surface water, 0.6%; ground water, 0.1%

Irrigation—surface water, 78.7%; ground water, 11.1%

Other—surface water, 0.1%; ground water, 3.7%

The total withdrawals average 1,130 million gallons per day

(4,275 million liters per day). About 18 percent is from ground

water sources, and 82 percent is from surface water sources.

Water commonly is scarce in areas away from the major streams.

The Dolores, Animas, and San Juan Rivers, which are perennial

streams in the northern end of the area, are major sources of

irrigation water. The headwater streams of the Rio Grande also

have water of excellent quality. The Navajo, Heron, and El

Vado Reservoirs store water for irrigation and recreation in this

area. The San Juan River is a high-quality, cold-water fishery

stream in northwestern New Mexico. It is used for municipal

and industrial supplies as well as irrigation. High salt loads

from southern tributary streams affect water quality in this area.

The quality of some surface water has been degraded by the

effects of upstream mining activities in the late 1800s. This

mining occurred mainly in the upper reaches of the streams

outside this MLRA.

Ground water is the primary source of drinking water in

many areas. In places some irrigation water is obtained from

deep wells. Cretaceous and Jurassic sediments (Dakota and

Morrison Formations and Entrada Sandstone) provide some

ground water of variable quality in southwestern Colorado. The

ground water in New Mexico is in Tertiary sandstone and in the

older sediments. It is soft to hard water and generally exceeds

the national drinking water standard for total dissolved solids.

Median levels of total dissolved solids are close to 1,000 parts

per million (milligrams per liter) in New Mexico. Because of

high sodium and sulfate levels, the water is of limited use for

drinking in many areas. Fresher water with lower levels of total

dissolved solids is near the recharge zones for these

consolidated sediments. Very salty water is at depth and away

from the recharge zones. Highly mineralized water leaks into

these aquifers from older and younger marine sediments above

and below the sandstone aquifers.

Some irrigation water is pumped from the valley fill in the

larger river valleys. It has a higher salt content than the river

water but otherwise is very similar in quality. Seepage of salty

water from the adjacent rocks containing soluble salts can

increase the sodium sulfate content, which limits the use of the

valley fill water.

Soils

The dominant soil orders in this MLRA are Alfisols,

Inceptisols, Mollisols, Entisols, and Aridisols. The soil moisture

regime is mainly ustic, but an aridic regime that is marginal to

ustic occurs in some areas. The soil temperature regime is mesic

or frigid. Mineralogy is dominantly mixed or smectitic.

In the warmer areas, shallow Ustorthents (Menefee series)

formed in residuum on shale hills and mesas. Shallow

Haplustalfs (Arabrab series) and Torriorthents (Rizno series)

formed in material weathered from sandstone on mesas, hills,

and cuestas. Moderately deep, loamy Haplargids (Gapmesa

series) and very deep, loamy Haplustalfs (Orlie series) formed in

slope alluvium derived from sandstone and shale on mesas or

fan remnants. Very deep, clayey Haplustepts (Roques series)

formed in alluvium derived from shale on valley sides. Very

deep, silty Haplustalfs (Cahona and Wetherill series) formed in

eolian material on hills and mesas.

In the cooler areas, very deep, clayey Haplustalfs (Goldbug

series) formed in slope alluvium derived from sandstone and

shale on hills and mesas. Shallow Argiustolls (Fivepine series)

formed in slope alluvium and residuum derived from sandstone.

Moderately deep Argiustolls (Nortez series) formed in eolian

material derived from sandstone on hills and mesas.

Biological Resources

The potential vegetation is grass and sagebrush at the lower

elevations. Pinyon-juniper woodland and ponderosa pine forests

are at mid elevations. Forests of Rocky Mountain Douglas-fir and

white fir are at the higher elevations. Some common plants are

Wyoming big sagebrush, western wheatgrass, galleta,

needleandthread, and blue grama at the lower elevations;

twoneedle pinyon, Utah juniper, Indian ricegrass, mountain

mahogany, ponderosa pine, Gambel oak, Arizona fescue, and

muttongrass at mid elevations; and Rocky Mountain Douglas-fir,

white fir, mountain muhly, common snowberry, Parry’s oatgrass,

and mountain brome at the higher elevations.

Some of the major wildlife species in this area are mule deer,

elk, coyote, black bear, mountain lion, black-tailed jackrabbit,

Gunnison’s prairie dog, badger, piñon jay, black-billed magpie,

mountain chickadee, red-breasted nuthatch, white-breasted
of the United States 101

nuthatch, collared lizard, fence lizard, and western rattlesnake.

Reservoirs and rivers provide most of the fish habitat in this

area. The ones at the higher elevations have cold-water species,

such as rainbow trout and brown trout, and the ones at the lower

elevations may have warm-water species, such as bass, bluegill,

crappie, and catfish.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 3%

Grassland—private, 41%; Federal, 39%

Forest—private, 7%; Federal, 5%

Urban development—private, 2%

Other—private, 3%

Nearly all of this area supports natural vegetation and is used

as grazing land or forestland. Cropland also is a significant land

use. Where irrigation water is available, irrigated crops, such as

wheat, barley, beans, oats, alfalfa, and hay, are grown. An area in

Colorado and Utah is used as nonirrigated cropland. The major

crops grown on this nonirrigated cropland are beans and winter

wheat. The pinyon-juniper woodlands are a source of fuel

wood. At the higher elevations, commercial timber is harvested,

principally ponderosa pine and Rocky Mountain Douglas-fir.

Some urban development is occurring in the vicinity of Santa

Fe.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the productivity of the soils, and

management of soil moisture. Conservation practices on

cropland generally include crop residue management,

minimum tillage, and irrigation water management. Proper

grazing use is a concern on grazing lands. The primary

concerns in timbered areas are controlling erosion along roads

and skid trails and minimizing surface compaction during

timber harvesting. 

Figure 38-1: Location of MLRA 38 in Land Resource Region D.

38—Mogollon Transition

This area (shown in fig. 38-1) is in Arizona (81 percent) and

New Mexico (19 percent). It makes up about 18,985 square

miles (49,195 square kilometers). The cities of Globe and

Prescott, Arizona, and Silver City, New Mexico, occur in this

MLRA. U.S. Highway 180 crosses this area in New Mexico, and

Interstate 17 crosses the middle of the area in Arizona. Parts of

the Prescott, Tonto, Gila, and Cibola National Forests are in this

area. The MLRA has numerous wilderness areas and national

forests. The Tuzigoot and Montezuma Castle National

Monuments and the Hualapai, Yavapai, Camp Verde, Lower

Camp Verde, and San Carlos Indian Reservations are in the part

of this area in Arizona.

Physiography

This area is in the Mexican Highland Section of the Basin

and Range Province of the Intermontane Plateaus. The area

consists of canyons and structural troughs and valleys.

Examples of the many mountain ranges in the area are the

Pinal, Sierra Ancha, and Mazatzal Mountains in Arizona and

the Big Burro and Mimbres Mountains in New Mexico.

Elevation ranges from 3,000 to 5,500 feet (915 to 1,675 meters)

in most areas and from 5,100 to 7,500 feet (1,555 to 2,285

meters) in the mountains.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows: Salt

(1506), 37 percent; Upper Gila (1504), 25 percent; Lower

Colorado (1503), 14 percent; Lower Gila (1507), 9 percent; Rio

Grande-Mimbres (1303), 8 percent; and parts of many other

hydrologic units, 7 percent. The Verde, Black, and Salt Rivers

are tributaries to the Gila River in this MLRA. A reach of the

Verde River has been designated a National Wild and Scenic

River in Arizona.

Geology

Most of this area is covered by deep alluvium washed in

from the adjacent mountains. These deposits of silt, sand, and

gravel are very young in the present-day drainages and much
102 Major Land Resource Areas

older on the valley floors and terraces. This MLRA is an area of

intensive volcanism. Isolated outcrops of granite are more than

1 billion years old. Most of the andesite and basalt flows are

Tertiary in age, forming in the past 50 million years. Some

basalts, however, formed around 4 million years ago, and

another series of intrusive rocks appeared in the late Cretaceous

to early Tertiary. Some outcrops of Paleozoic sediments are

associated with the uplift in the vicinity of the older intrusive

rock units. Some of these sediments have been metamorphosed.

Climate

The average annual precipitation is 10 to 37 inches (255 to

940 millimeters) in most of this area. More than half of the

precipitation occurs as high-intensity, convective thunderstorms

during July, August, and September. Because of Pacific frontal

storms, a second rainy season occurs from December to March.

Snow falls occasionally in winter. The average annual air

temperature is 47 to 70 degrees F (8 to 21 degrees C). The

freeze-free period averages 255 days and ranges from 145 to

365 days, decreasing in length with increasing elevation.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 6.8%; ground water, 0.0%

Livestock—surface water, 13.7%; ground water, 0.1%

Irrigation—surface water, 19.1%; ground water, 13.7%

Other—surface water, 38.3%; ground water, 8.2%

The total withdrawals average 37 million gallons per day

(140 million liters per day). About 22 percent is from ground

water sources, and 78 percent is from surface water sources. This

MLRA supplies water for much of the adjoining irrigated land.

Because more than one-half of the annual precipitation occurs

in winter, there is a general deficiency of moisture during the

growing season. Several of the larger streams and a few of their

larger tributaries are perennial streams. Much of the water is

stored in reservoirs near or below the southern edge of the area

and is used for irrigation and for municipal water supplies in

the Sonoran Basin and Range MLRA to the south. Small

natural and artificial lakes at the higher elevations are used for

fishing and other kinds of recreation. Annual runoff into all

reservoirs is highly variable, and most of the smaller lakes and

reservoirs are dry in some years. The surface water is of good

quality and is suitable for most uses with minimal treatment. A

high load of suspended sediment is one of the primary waterquality issues in this MLRA.

Ground water is limited and generally occurs at great depth

in alluvial deposits along some of the larger streams in this

area. The quality of this water varies considerably, depending

on the composition, location, and depth of the alluvium. Some

alluvium has evaporite deposits, and some has high levels of

sulfate. Some springs yield saline water. The median

concentration of total dissolved solids is generally suitable for

almost all uses in this area. Very little runoff or precipitation is

available to recharge the alluvial aquifers in the area, so ground

water levels have declined. A few windmills furnish water for

livestock and wildlife. Some earthen water tanks are throughout

the area. The fractures and joints in the igneous, metamorphic,

and sedimentary bedrock have small amounts of ground water.

Soils

The dominant soil orders in this MLRA are Aridisols,

Alfisols, and Mollisols. The soils dominantly have a thermic or

mesic soil temperature regime, an aridic or ustic soil moisture

regime, and smectitic or mixed mineralogy and formed in

alluvium. They are very shallow to very deep and are well

drained and somewhat excessively drained. Torrertic

Haplustolls (Ashcreek series) and Torrertic Haplustalfs

(Cloverdale series) formed on alluvial fans. Ustic Haplargids

(Eskiminzin series) formed on hills and mountains. Pachic

Haplustolls (Lanque series) formed on fan terraces and stream

terraces. Cumulic Haplustolls (Rafter series) formed on flood

plains and alluvial fans.

Biological Resources

This area supports forest, savanna, desert shrub, and

grassland vegetation. Pine-oak woodlands are at the higher

elevations, where ponderosa pine, Douglas-fir, live oak, New

Mexico locust, Mexican pinyon, buckbrush, and manzanita

grow with an understory of muhlys, bluegrasses, sedges, pine

dropseed, and squirreltail. Evergreen woodland savannas are at

intermediate elevations, where Mexican blue oak, Emory and

Arizona white oaks, alligator and one-seed junipers, jojoba, and

turbinella oak are the dominant species and cone beardgrass,

sideoats grama, blue grama, Texas bluestem, plains lovegrass,

sprucetop grama, threeawns, and needlegrass characterize the

understory. Whitethorn, soaptree yucca, fourwing saltbush,

mesquite, and ocotillo grow on the drier soils at the lower

elevations. The understory at these elevations consists of

Rothrock grama, blue grama, black grama, alkali sacaton, curly

mesquite, plains bristlegrass, bush muhly, and lemongrass.

Some of the major wildlife species in this area are mule deer,

white-tailed deer, mountain lion, coyote, bobcat, raccoon,

skunk, white-throated woodrat, white-footed mouse, gopher

snake, king snake, western diamondback rattlesnake, western

whiptail lizard, side-blotched lizard, tree lizard, red-tailed hawk,

Cooper’s hawk, golden eagle, prairie falcon, raven, turkey

vulture, meadowlark, ladder-back woodpecker, ash-throated

flycatcher, canyon wren, and rough-winged swallow.
of the United States 103

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—private, 38%; Federal, 40%

Forest—private, 8%; Federal, 10%

Urban development—private, 1%

Other—private, 3%

About one-half of thus area is federally owned. Most of the

area is used for livestock grazing. Many tracts of rangeland are

subdivided for community development. The main

management concern on rangeland is controlling the

distribution of grazing. Invasion of brushy species and local

gully erosion are symptoms of overgrazing.

The major soil resource concerns are maintenance of the

content of organic matter and productivity of the soils and the

hazard of water erosion. Conservation practices on rangeland

include fencing and development of watering facilities, which

facilitate grazing management systems; brush management,

which removes undesirable and introduced invasive species; and

erosion control, which helps to prevent gullying and

concentrated waterflow. 

Figure 39-1: Location of MLRA 39 in Land Resource Region D.

39—Arizona and New Mexico Mountains

This area (shown in fig. 39-1) is in New Mexico (59 percent)

and Arizona (41 percent). It makes up about 15,150 square

miles (39,255 square kilometers). The cities of Flagstaff and

Springerville, Arizona, and Reserve, Ruidoso, and Cloudcroft,

New Mexico, occur in this MLRA. Interstates 17 and 40

intersect in this area, in Flagstaff, and U.S. Highway 180

crosses this area in New Mexico. Parts of the Kaibab,

Coconino, Gila, Apache-Sitgreaves, and Cibola National

Forests are in this area. The part of this area in Arizona includes

Sunset Crater and Walnut Canyon National Monuments. It also

includes a large part of the Fort Apache Indian Reservation. The

Navajo Army Depot and Naval Observatory Station are west of

Flagstaff.

Physiography

The western two-thirds of this area is primarily in the Grand

Canyon Section of the Colorado Plateaus Province of the

Intermontane Plateaus. The northern half of the eastern third of

the area is in the Datil Section of the same province and

division. The southern half of the eastern third of the area and

part of the southern half of the western two-thirds are in the

Mexican Highland Section of the Basin and Range Province of

the Intermontane Plateaus. This MLRA is characterized by

volcanic fields and gently dipping sedimentary rocks eroded

into plateaus, valleys, and deep canyons. Elevation ranges from

4,000 to 7,000 feet (1,220 to 2,135 meters) in the southern half

of the area. North of the Mogollon Rim, it rises to more than

7,500 feet (2,285 meters) and drops northward to 5,000 or 6,000

feet (1,525 to 1,830 meters). Included in this area are the two

highest points in Arizona, Baldy Peak at 11,403 feet (3,476

meters) and Humphreys Peak at 12,670 feet (3,863 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Upper Gila (1504), 26 percent; Little Colorado (1502), 21

percent; Salt (1506), 19 percent; Rio Grande-Elephant Butte

(1302), 17 percent; Upper Pecos (1306), 8 percent; and parts of

numerous other units, 9 percent. The Black, Blue, and Little

Colorado Rivers are the major rivers in this MLRA.

Geology

Cenozoic volcanic rocks are an important feature of this

area. These rocks are from large central type volcanoes, such as

the San Francisco Peaks near Flagstaff, and from smaller,

coalescing volcanoes that produced extensive sheets of lavas

and pyroclastic rocks. Various sedimentary sections of the

Colorado Plateau also are evident. They are characterized and

affected by alternating resistant and weak rock strata that form

ledges, cliffs, mesas, and benches separated by slopes and

valleys. Relief is caused more by the cutting of deep canyons

into moderately flat terrain than by the deformation of

mountains and valleys. The southern and eastern parts of the

MLRA include Permian and Cretaceous sedimentary rock over

a Precambrian granite core that is exposed in places at the

higher elevations.
104 Major Land Resource Areas

Climate

The average annual precipitation is 15 to 30 inches (380 to

760 millimeters) in most of this area. It is 9 to 15 inches (230 to

380 millimeters) in a few of the lower areas along the edges of

the MLRA. It can be as much as 43 inches (1,090 millimeters)

in the mountains. More than half of the precipitation occurs as

high-intensity, convective thunderstorms during July, August,

and September. Because of Pacific frontal storms, a second

rainy season occurs from December to March. Snow falls in

winter. The average annual air temperature is 36 to 55 degrees F

(2 to 13 degrees C). The freeze-free period averages 135 days

and ranges from 60 to 205 days, decreasing in length with

increasing elevation.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 3.7%; ground water, 0.0%

Livestock—surface water, 9.1%; ground water, 2.5%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 17.2%; ground water, 67.4%

The total withdrawals average 13 million gallons per day

(50 million liters per day). About 70 percent is from ground

water sources, and 30 percent is from surface water sources.

Since more than half of the annual precipitation occurs during

winter, there is a general deficiency of moisture during the

growing season.

This area has important watersheds that provide water to the

central part of Arizona. Several of the larger streams, such as the

Black, White, Verde, and Salt Rivers, and a few of their larger

tributaries maintain perennial flow. Much of the water is stored

in reservoirs near or below the southern edge of the area and is

used for irrigation or municipal water supply in the MLRAs to

the south. The municipal water supply for Flagstaff and

Williams is in part obtained from small reservoirs. This MLRA

has several lakes and reservoirs. Small natural or artificial

lakes at the higher elevations are used for fishing and other

kinds of recreation. Annual runoff into all reservoirs is highly

variable, and most of the smaller lakes and reservoirs are dry

during some years. The surface water is suitable for almost all

uses. A high sediment load is the primary water-quality

problem.

Limited amounts of ground water for livestock and domestic

use generally are only in faulted and fractured bedrock in areas

of this MLRA. The water generally has less than 1,000 parts per

million (milligrams per liter) total dissolved solids. Fresher

water with lower levels of total dissolved solids is near the

recharge zones for the bedrock aquifers. Very salty water is at

depth and away from the recharge zones. Some springs yield

saline water.

Soils

The dominant soil orders in this MLRA are Inceptisols,

Mollisols, Alfisols, and Entisols. Most of the soils in the area

have a frigid or mesic soil temperature regime, depending

mainly on elevation, but the soils at the highest elevations have

a cryic temperature regime. Argiustolls (Brolliar, Sponseller,

Ruidoso, and Ess series) formed in intrusive and extrusive

volcanic materials, dominantly basalt. Examples of Haplustolls

are the Tularosa and Blanca series. Examples of Ustolls with a

cryic temperature regime are the Caballo and Supervisor series.

At the lower elevations, Haplustalfs and Paleustalfs (Dandrea,

McVickers, Overgaard, and Hogg series), Ustorthents (Mirabal

and Telephone series), Haplustolls (Tortugas, Tularosa, and

Ackmen series), and Calciustepts (Cibeque series) overlie

different rock types.

Biological Resources

This area includes grasslands on the deeper soils; mixed

shrub-grasslands on shallow, rocky soils; and timber on soils

that are shallow to bedrock. Ponderosa pine occurs in the

largest portion of the intermediate elevations in the area. At the

higher elevations, spruce and fir dominate. Areas at the highest

elevations, above 11,000 feet (3,350 meters), support alpine

vegetation. At the lower elevations, ponderosa pine grades into

stands of pinyon-juniper on north-facing slopes and woodland

of mixed oak, pine, and juniper on south-facing slopes. The

principal grasses are fescues, bluegrasses, bromegrass, and

muhly at the higher elevations; needlegrass, western

wheatgrass, bottlebrush squirreltail, and muttongrass at

intermediate elevations; and grama grasses, spike muhly,

junegrass, cane bluestem, and needlegrass at the lower

elevations.

Some of the major wildlife species in this area are mule deer,

white-tailed deer, mountain lion, coyote, bobcat, raccoon, wolf,

black bear, and elk.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—private, 9%; Federal, 7%

Forest—private, 12%; Federal, 63%

Urban development—private, 2%

Water—Federal, 1%

Other—private, 1%; Federal, 5%

About three-fourths of this area is federally owned. Most

of the area is used for timber production or livestock grazing.

Many tracts of rangeland are subdivided for community

development. The main management concern on rangeland

is controlling the distribution of grazing. Invasion of brushy

species and local gully erosion are symptoms of overgrazing.
of the United States 105

The major soil resource concerns are maintenance of the

content of organic matter and productivity of the soils and the

hazard of water erosion. Conservation practices on rangeland

include fencing and development of watering facilities, which

facilitate grazing management systems; brush management,

which removes undesirable and introduced invasive species; and

erosion control, which helps to prevent gullying and

concentrated waterflow. 

Figure 40-1: Location of MLRA 40 in Land Resource Region D.

40—Sonoran Basin and Range

This area is almost entirely in Arizona, but it includes a very

small part of California (fig. 40-1). It makes up about 31,765

square miles (82,310 square kilometers). The cities of Yuma,

Tucson, and Phoenix are in this MLRA. Interstate 10 crosses the

center of this area and turns to the southeast outside of Phoenix.

Interstate 17 ends in Phoenix. Interstate 19 runs from Tucson to

the Mexican border. Interstate 8 crosses the southern part of the

MLRA. It ends where it intersects Interstate 10 southeast of

Phoenix. Many wilderness study areas occur in this MLRA. The

Tonto and Prescott National Forests and Saguaro and Organ

Pipe Cactus National Monuments also occur in this MLRA.

The Yuma Proving Grounds, the Barry M. Goldwater Air Force

Bombing Range, and the Tohono O’Odham, Colorado River,

Salt River, and Gila River Indian Reservations are in the

area.

Physiography

This area is in the Sonoran Desert Section of the Basin and

Range Province of the Intermontane Plateaus. Many short,

fault-block mountain ranges trending southeast to northwest

rise abruptly from the smooth or gently sloping desert valley

floors. These include the Painted Rock, Gila Bend, Big Horn,

Copper, Granite, and Santa Rosa Mountains. Elevation ranges

from 980 to 3,600 feet (300 to 1,100 meters) in most of this

area, but it is as high as 4,590 feet (1,400 meters) in the

mountains.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Lower Gila (1507), 41 percent; Middle Gila (1505), 25 percent;

Lower Colorado (1503), 20 percent; Sonora (1508), 9 percent;

and Salt (1506), 5 percent. The Salt River intersects the Gila

River south of Phoenix. The Gila River then flows west across

the southern part of the MLRA to the Colorado River.

Geology

Most of this area is covered by deep alluvium washed in

from the adjacent mountains. These deposits of silt, sand, and

gravel are very young in the present-day drainageways and

much older on the valley floors and terraces. This MLRA is an

area of intensive volcanism. Isolated outcrops of granite are

more than 1 billion years old. Most of the andesite and basalt

flows are Tertiary in age, forming in the past 50 million years.

Some basalts, however, formed around 4 million years ago, and

another series of intrusives appeared in the late Cretaceous to

early Tertiary. Some outcrops of Paleozoic sediments are

associated with the uplift in the vicinity of the older intrusives.

Some of these sediments have been metamorphosed.

Climate

The average annual precipitation is 3 to 10 inches (75 to 255

millimeters) in most of this area. Rainfall can average 22 inches

(560 millimeters) per year in the mountain ranges. Most of the

rainfall occurs as high-intensity, convective thunderstorms,

mainly from July to September, and as Pacific frontal storms

from December to March. Snowfall is rare, except at the higher

elevations. The average annual air temperature is 58 to 74

degrees F (15 to 23 degrees C). The freeze-free period averages

285 days and ranges from 205 to 365 days, decreasing in length

with increasing elevation.
106 Major Land Resource Areas

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 4.9%; ground water, 6.4%

Livestock—surface water, 0.5%; ground water, 0.2%

Irrigation—surface water, 52.7%; ground water, 31.7%

Other—surface water, 1.6%; ground water, 2.1%

The total withdrawals average 5,995 million gallons per day

(22,690 million liters per day). About 40 percent is from ground

water sources, and 60 percent is from surface water sources.

Most of the population in Arizona lives in this MLRA, and a

little over 90 percent of all the water used in the State is used in

this area. Precipitation is sparse. Water for irrigation and other

uses is stored in a reservoir system on the Salt River. No

perennial streams originate or run through the area because the

water of the larger drainages is impounded by reservoirs

upstream from the cultivated lands. The surface water from the

mountains generally is of good quality, and its use is not

limited. The quality of the water is naturally degraded by

dissolved salts picked up as streams cross various soil and

geologic deposits. Irrigation return flows also raise the levels of

dissolved salts and suspended sediments, causing local waterquality problems.

The alluvial aquifers in this area are the most productive in

Arizona. Some of the more significant aquifers are in the

Colorado, Salt (or Gila), and Lower Santa Cruz River basins

and in the Yuma Valley and San Simon Wash basins. Water for

irrigation is pumped from deep wells in the alluvial aquifers,

and the ground water table continually drops. All of the surface

water in Arizona is appropriated, and little water usually is left

to recharge the alluvial aquifers. The quality of the ground

water varies considerably, depending on the composition,

location, and depth of the alluvium. Some alluvium contains

evaporate deposits and volcanic rocks, and high levels of sulfate

can occur where these rocks occur in abundance. The median

concentration of total dissolved solids is typically less than

1,000 parts per million (milligrams per liter), so the ground

water is of good enough quality for almost all uses.

Soils

The dominant soil orders in the MLRA are Aridisols and

Entisols. The soils in the area dominantly have a thermic or

hyperthermic soil temperature regime, an aridic soil moisture

regime, and mixed mineralogy and formed in alluvium. They

are very shallow to very deep and are well drained and

somewhat excessively drained. Haplocambids (Denure and

Hayhook series), Haplocalcids (Gunsight and Stagecoach

series), Calciargids (Mohall and Pinaleno series), and

Natrargids (Casa Grande series) formed on fan terraces and

relict basin floors. Torrifluvents (Antho and Comoro series)

formed on alluvial fans and flood plains. Shallow or very

shallow Torriorthents (Cellar and Quilotosa series) formed on

hills and mountains.

Biological Resources

This area supports desert shrub vegetation. The giant

saguaro cactus is a major species. Bursage, desert wolfberry,

ocotillo, cholla, desert saltbush, mesquite, brittlebush,

burroweed, pricklypear, desert broom, and creosotebush are the

dominant desert shrubs. Bush muhly, Arizona cottontop,

threeawns, and fluffgrass are the main understory plants. Winter

annuals can grow in some areas, depending on the amount of

winter precipitation. Joshua-tree and littleleaf paloverde mixed

with some honey mesquite are on stony or rocky sites. These

sites have an understory of Mormon tea, pricklypear, cholla,

ocotillo, desert saltbush, and grasses, such as tridens, bush

muhly, tobosa, Arizona cottontop, and desert needlegrass. At

the lower elevations, creosotebush, ironwood, mesquite,

burroweed, and catclaw are associated with an understory of

threeawns and annuals, such as red fescue, bluegrasses,

fiddleneck, indianwheat, globemallow, and filaree.

Some of the major wildlife species in this area are mule deer,

desert bighorn sheep, antelope, javelina, coyote, fox, raccoon,

bats, rattlesnake, bullsnake, coachwhip, kingsnake, and quail.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 5%

Grassland—private, 36%; Federal, 47%

Urban development—private, 4%

Other—private, 4%; Federal, 4%

More than one-half of this area is federally owned. Most of

the area is desert that can be used for limited grazing during

periods of favorable moisture. Irrigated areas are used for

cotton, alfalfa, barley, and other small grains. In areas where

water supplies are favorable, lettuce, carrots, cabbage,

cauliflower, melons, other market vegetables, and citrus are

grown. Rapid urbanization around the larger communities is

greatly reducing the acreage of cropland.

The major soil resource concern is the absence of soil

sustainability, resulting in no soil loss tolerance within this

extremely arid environment. Other resource concerns include

declining water tables and accumulation of salts in the soils

used for crops. Efficiently using the limited water supply is an

important management concern. Conservation practices on

cropland are crop rotation, crop residue management, minimum

tillage, nutrient and pest management, land leveling, ditch

lining, irrigation water management, and pasture and hayland

management. 
of the United States 107

Figure 41-1: Location of MLRA 41 in Land Resource Region D.

41—Southeastern Arizona Basin and

Range

This area (shown in fig. 41-1) is in Arizona (89 percent) and

New Mexico (11 percent). It makes up about 15,730 square

miles (40,765 square kilometers). The cities of Nogales, Bisbee,

and Sierra Vista, Arizona, are in this MLRA. Interstate 10 bisects

this area, and the towns of Benson and Willcox are along the

freeway. The Coronado National Forest, the Fort Huachuca

Military Reservation, the Fort Bowie National Historic Site,

and the Chiricahua and Tumacacori National Monuments are in

this MLRA. The eastern edge of the Papago Indian Reservation

and the southern part of the San Carlos Indian Reservation also

are in this MLRA.

Physiography

Most of this area is in the Mexican Highland Section of the

Basin and Range Province of the Intermontane Plateaus. The

eastern one-fifth of the area is in the Sonoran Desert Section of

that same province and division. This MLRA has mountain

ranges that trend southeast to northwest and has relatively

smooth valleys between the mountains. Examples of the many

mountain ranges are the Chiricahua, Dragoon, Swisshelm, and

Pedregosa Mountains. In the vicinity of Willcox, there is a

distinct closed basin called the Willcox Playa. The southeast

boundary of the part of this MLRA in New Mexico is the

Continental Divide. Elevation ranges from 2,620 to 4,590 feet

(800 to 1,400 meters) in most areas. It generally ranges from

4,920 to 5,900 feet (1,500 to 1,800 meters) in the mountains.

On some peaks, however, it can reach almost 8,900 feet (2,715

meters). On Mt. Graham, in Arizona, it reaches 10,717 feet

(3,267 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Middle Gila (1505), 51 percent; Upper Gila (1504), 33 percent;

Sonora (1508), 14 percent; and Rio Grande-Mimbres (1303), 2

percent. The Gila River runs through the northern end of this

area. The San Francisco, San Simon, and San Pedro Rivers are

tributaries to the Gila River in this MLRA.

Geology

Most of this area is covered by deep alluvium washed in

from the adjacent mountains. These deposits of silt, sand, and

gravel are very young in the present-day drainageways and

much older on the valley floors and terraces. This MLRA is an

area of intensive volcanism. Isolated outcrops of granite are

more than 1 billion years old. Most of the andesite and basalt

flows are Tertiary in age, forming in the past 50 million years.

Some basalts, however, formed around 4 million years ago, and

another series of intrusives appeared in the late Cretaceous to

early Tertiary. Some outcrops of Paleozoic sediments are

associated with the uplift in the vicinity of the older intrusives.

Some of these sediments have been metamorphosed.

Climate

The average annual precipitation is 9 to 20 inches (230 to

510 millimeters) in most of this area, but it is as much as 45

inches (1,145 millimeters) at the higher elevations. More than

half of the precipitation occurs as high-intensity, convective

thunderstorms during July, August, and September. Because of

Pacific frontal storms, a second rainy season occurs from

December to March. Snow falls occasionally in winter. The

average annual air temperature is 47 to 68 degrees F (8 to 20

degrees C). The freeze-free period averages 245 days and ranges

from 160 to 335 days, decreasing in length with elevation.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 0.6%; ground water, 1.3%

Livestock—surface water, 1.8%; ground water, 1.3%

Irrigation—surface water, 16.6%; ground water, 60.6%

Other—surface water, 5.8%; ground water, 12.1%

The total withdrawals average 155 million gallons per day

(585 million liters per day). About 75 percent is from ground

water sources, and 25 percent is from surface water sources.
108 Major Land Resource Areas

There are no lakes or reservoirs of consequence in this area.

Surface water quality is generally satisfactory. Small artesian

flows occur along parts of the San Pedro River.

Water for irrigation generally is obtained by pumping

ground water from deep wells in the alluvial aquifers. Some of

the more significant aquifers are in the Avra, Altar, and Upper

Santa Cruz River basins and in the Safford and Wilcox basins.

There has been a noticeable decline in the level of the ground

water in all of these aquifers. Very little runoff or precipitation

is available to recharge the alluvial aquifers in the area. The

quality of the ground water varies considerably, depending on

the composition, location, and depth of the alluvium. Some

alluvium has evaporite deposits, and some has volcanic rocks,

which produce high levels of sulfate. The median concentration

of total dissolved solids in four of the five basins is typically

less than 500 parts per million (milligrams per liter), so the

ground water generally is of good quality for almost all uses in

this area. In water from the Safford basin, in the northern part of

this area, the median concentration of total dissolved solids

exceeds 1,000 parts per million and the sulfate levels exceed the

national drinking water standard of 250 parts per million

(milligrams per liter).

Soils

The dominant soil orders in this MLRA are Aridisols,

Entisols, Alfisols, and Mollisols. The soils in the area

dominantly have a thermic soil temperature regime, an aridic or

ustic soil moisture regime, and mixed mineralogy and formed

in alluvium. They are very shallow to very deep and are well

drained and somewhat excessively drained. Ustic Torrifluvents

(Ubik and Keysto series) formed on flood plains. Calcids

(Blakeney series) formed on terraces. Argids (Eloma and

Forrest series) and Aridic Haplustalfs (Gardencan and Crowbar

series) formed on fan terraces. Shallow and very shallow

Haplustolls (Far and Yarbam series) formed on hills and

mountains.

Biological Resources

This area supports forest, savanna, and desert shrub

vegetation. Pine-oak woodlands are at the higher elevations,

where ponderosa pine, Douglas-fir, live oak, New Mexico

locust, Mexican pinyon, buckbrush, and manzanita grow along

with an understory of muhlys, bluegrasses, sedges, pine

dropseed, and squirreltail. Evergreen woodland savannas are at

intermediate elevations, where Mexican blue oak, Emory oak,

and turbinella oak are the dominant species and cone

beardgrass, sideoats grama, blue grama, Texas bluestem, plains

lovegrass, sprucetop grama, threeawns, and needlegrass

characterize the understory. Whitethorn, soaptree yucca,

fourwing saltbush, mesquite, and ocotillo grow on the drier

soils at the lower elevations. The understory on these sites

consists of Rothrock grama, black grama, alkali sacaton, curly

mesquite, plains bristlegrass, bush muhly, and lemongrass.

Some of the major wildlife species in this area are mule deer,

white-tailed deer, mountain lion, coyote, bobcat, raccoon,

skunk, white-throated woodrat, white-footed mouse, gopher

snake, king snake, western diamondback rattlesnake, prairie

rattlesnake, coachwhip, patch-nosed snake, western whiptail

lizard, side-blotched lizard, tree lizard, canyon tree frog, redtailed hawk, Cooper’s hawk, golden eagle, prairie falcon, raven,

turkey vulture, meadowlark, ladder-back woodpecker, ashthroated flycatcher, canyon wren, and rough-winged swallow.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 2%

Grassland—private, 59%; Federal, 34%

Urban development—private, 2%

Other—private, 1%; Federal, 2%

About one-third of this area is federally owned. Most of the

area is used for livestock grazing. Some areas are used for

cotton, corn, alfalfa, small grains, or other farm crops. Many

tracts of rangeland and cropland are subdivided for community

development.

The major soil resource concerns are maintenance of the

content of organic matter and productivity of the soils and the

hazard of water erosion. Other resource concerns on cultivated

land include declining water tables and a short supply of

irrigation water.

Conservation practices on cropland generally include

irrigation water management, solid-set sprinklers, micro

irrigation with subsoil drip irrigation and micro sprinklers,

uniform slope leveling, irrigation pipelines, crop rotation,

pasture and hayland management, minimum tillage, and crop

residue management.

The important conservation practices on rangeland generally

include those that help to control the distribution and intensity

of grazing. They also include fencing, development of watering

facilities, and range management. Invasion of brushy species

and local gully erosion are symptoms of overgrazing. 
of the United States 109

Figure 42-1: Location of MLRA 42 in Land Resource Region D.

42—Southern Desertic Basins, Plains, and

Mountains

This area (shown in fig. 42-1) is in Texas (51 percent) and

New Mexico (49 percent). It makes up about 55,970 square

miles (145,040 square kilometers). Albuquerque, Deming, Las

Cruces, Roswell, Artesia, and Carlsbad, New Mexico, and El

Paso, Pecos, Alpine, and Fort Stockton, Texas, are in this

MLRA. Interstates 10, 20, and 25 connect these towns. A

small part of the Cibola National Forest is in this MLRA. The

Big Bend National Park, in Texas, is in the southeastern tip

of this area. The Fort Bliss Military Reservation is northeast

of El Paso, Texas, and extends into New Mexico. Holloman

Air Force Base is in this MLRA, and the White Sands Missile

Range and National Monument is in the part of the MLRA

in south-central New Mexico. The Sandia, Laguna,

Canoncito, and Isleta Indian Reservations are near

Albuquerque.

Physiography

Approximately three-fourths of this MLRA is in the Mexican

Highland Section of the Basin and Range Province of the

Intermontane Plateaus. A small area between the western twothirds and eastern one-third of the MLRA is in the Sacramento

Section of the same province and division. The northeastern and

eastern parts of the MLRA are in three different sections of the

Great Plains Province of the Interior Plains. From north to

south, these are the Pecos Valley, High Plains, and Edwards

Plateau Sections. The Pecos Valley Section makes up most of

this part of the MLRA. This MLRA is distinguished by

intermontane desert basins and broad valleys bordered by

gently sloping to strongly sloping bajadas, alluvial fans, and

terraces. Steep mountain ranges trending north to south occur

in the western part of the area. Elevation ranges from 2,600 to

4,950 feet (795 to 1,510 meters) in areas on the plains and

basins to more than 8,500 feet (2,590 meters) in the mountains.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Lower Pecos (1307), 26 percent; Rio Grande Closed Basins

(1305), 21 percent; Rio Grande-Amistad (1304), 18 percent;

Rio Grande-Mimbres (1303), 15 percent; Upper Pecos (1306),

9 percent; Rio Grande-Elephant Butte (1302), 9 percent; and

Upper Gila (1504), 2 percent. The Rio Grande is the largest

river in this area. It flows southeast from New Mexico and

eventually forms the international boundary between Mexico

and the United States. Elephant Butte and Caballo Reservoirs

are on the part of the Rio Grande in New Mexico. The Pecos

River flows through the southeastern portion of New Mexico

and continues into Texas. Red Bluff Reservoir, on the Pecos

River, is the point of lowest elevation in New Mexico.

Geology

The linear, isolated mountain ranges in this area are

primarily tilted fault blocks modified by erosion. Mesozoic and

Paleozoic sediments overlying granitic intrusions of

Precambrian age are exposed in these tilted blocks. Tertiary

volcanic and intrusive igneous rocks occupy about 2.5 million

acres in the Texas Big Bend region. Quaternary and Tertiary

continental sediments accumulated to form the aggraded desert

plains lying between the mountain ranges. Some intermontane

basins are bolsons (internally drained desert basins), although

most are semi-bolsons (which are externally drained). Alluvial

fan deposits are common at the bases of most mountains.

Quaternary and Tertiary volcanic rocks consisting of basalt,

andesite, and rhyolite also are in this area.

The Rio Grande flows through a series of interconnected

grabens (down-dropped fault blocks that form a rift valley)

called the Rio Grand Rift. The Rio Grand Rift is an area of

extension and collapse within the North American continental

plate. Sediments deposited by the Rio Grande include sands,

gravel, and cobbles. Basalt flows and volcanic vents flanking

the river system are indicators of volcanic activity associated

with the formation of the rift valley.

Climate

The average annual precipitation is 8 to 14 inches (205 to

355 millimeters) in the eastern and southern parts of this area

and 12 to 18 inches (305 to 455 millimeters) in the northern
110 Major Land Resource Areas

and western parts. It is as much as 24 inches (610 millimeters)

in a few scattered mountains. Most of the rainfall occurs as

high-intensity, convective thunderstorms from midspring to

midautumn. This area does not receive significant amounts of

winter precipitation. The average annual temperature is 50 to

71 degrees F (10 to 22 degrees C), decreasing to the north and

in the higher elevations. The freeze-free period averages 230

days and ranges from 165 to 300 days, decreasing in length

with elevation.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 2.1%; ground water, 9.0%

Livestock—surface water, 0.7%; ground water, 0.8%

Irrigation—surface water, 52.2%; ground water, 28.9%

Other—surface water, 1.4%; ground water, 4.9%

The total withdrawals average 1,955 million gallons per day

(7,400 million liters per day). About 44 percent is from ground

water sources, and 56 percent is from surface water sources.

Scarce surface water and low precipitation are severe limitations

on the rangeland in this MLRA. The Rio Grande and Pecos

Rivers and a few of their larger tributaries are the only perennial

streams. Reservoirs control flooding and allow timely delivery

of irrigation water. Most of the surface water is used for

irrigation. The Rio Grande has water that is suitable for most

uses, but high salinity restricts use of water from the Pecos

River. Suspended sediment loads, urban and industrial waste

discharges, and saline irrigation return flows cause most of the

water-quality problems in this area.

Ground water in deep valley and basin fill provides water for

public supply, domestic use, livestock, and some irrigation.

Unconsolidated sand and gravel sediments in basin fill are the

primary aquifers in this area. Basin fill sediments in the

southeast corner of New Mexico are actually part of the High

Plains (Ogallala) aquifer. In Texas, water from the basin fill

aquifer is typically hard or very hard and has a median

concentration of about 770 parts per million (milligrams per

liter) total dissolved solids. In New Mexico, this ground water

has 400 to 700 parts per million total dissolved solids. The

water tends to increase in salinity farther downstream because

of recharge from irrigation return flows. About 40 percent of the

samples tested from this aquifer in Texas contained levels of

nitrate exceeding the national drinking water standard of 10

parts per million. Most of the samples tested in New Mexico

showed nitrate levels of less than 4 parts per million.

The quality of the ground water in alluvium aquifers in the

Rio Grande Valley is similar to the water quality in the basin fill

deposits. Water in the Pecos River Valley alluvium is unsuitable

for most uses because it is saline. Dissolution of evaporite

deposits in the aquifer and in the adjacent Pecos River Valley

Limestone aquifer are the primary sources of the salinity. Water

from deeper halite (sodium chloride) deposits also seeps into

the valley fill and contributes to the salinity problem.

Limestone in the Edwards-Trinity aquifer on the Edwards

Plateau occurs in a small part of the southeast corner of this

area, in Texas. It has water that is very similar in quality to the

water in the Rio Grande alluvium and basin fill deposits. The

ground water from the Edwards-Trinity aquifer, however,

typically has higher levels of total dissolved solids than the Rio

Grande Valley ground water and is used very little in this

MLRA.

Soils

The dominant soil orders in this MLRA are Aridisols, Entisols,

Mollisols, and Vertisols. The soils generally are moderately deep

to very deep, well drained, and loamy or clayey. Some of the soils

are shallow or very shallow over a petrocalcic horizon or bedrock.

Most have a thermic soil temperature regime, an aridic soil

moisture regime, and carbonatic or mixed mineralogy. Sizable

tracts on the Trans-Pecos Texas Mixed Prairie have an ustic

moisture regime. Soils on the highest mountain peaks have a

mesic temperature regime, whereas soils along the Rio Grande in

the Big Bend region are hyperthermic.

Calciargids (Berino and Stellar series) formed in alluvium on

fan piedmonts, piedmonts, fan terraces, and stream terraces and

in basins. Haplocalcids formed in limestone residuum on hills,

mesas, and divides (Bissett, Santaelena, and Dozer series); in

alluvium on fans, fan remnants, plains, and valley floors

(Corazones, Chamberino, Stovall, and Stillwell series); and in

eolian deposits on uplands (Wink series). Haplocambids

(Pajarito series) formed in alluvium on plains, bajadas, and

alluvial fans. Haplargids (Pyote series) formed in loamy eolian

deposits or alluvium on uplands. Petrocalcids formed in

gravelly alluvium on fan piedmonts, terraces, and ridges

(Delnorte, Paisano, and Tencee series) and in loamy sediments

on plains, mesas, and fans (Simona and Upton series).

Torripsamments (Aguena, Copia, and Yturbide series) formed

in eolian deposits on dunes and sand sheets. Haplustolls

(Brewster series) and Argiustolls (Mainstay series) formed in

colluvium underlain by igneous rock on hills and mountains.

Haplotorrerts (Verhalen series) formed in clayey alluvium on

terraces and alluvial plains.

Biological Resources

This area supports desert grass-shrub vegetation. Giant

dropseed, mesa dropseed, and scattered shrubs, such as sand

sagebrush and yuccas, grow on the sandier soils. Creosotebush,

tarbush, and catclaw grow on gravelly, calcareous soils on

footslopes. Giant sacaton, vine-mesquite, desertwillow, and

brickellbush grow in drainageways and depressions. The

dominant grass species include blue grama, black grama, and
of the United States 111

sideoats grama on prairie grasslands and mountain footslopes.

Juniper, pinyon, and scattered ponderosa pine are on the upper

mountain slopes.

Some of the major wildlife species in this area are mule deer,

white-tailed deer, antelope, javelina, mountain lion, coyote,

desert fox, gray fox, bobcat, badger, scaled quail, and mourning

dove. The species of fish in the area include black bass, channel

catfish, and sunfish.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 3%

Grassland—private, 64%; Federal, 26%

Forest—Federal, 1%

Urban development—private, 2%

Other—private, 1%; Federal, 3%

Federal land makes up nearly one-third of this area,

primarily in New Mexico. The rest of the land is mainly in

farms, ranches, or other private holdings. Two-thirds or more of

the area is rangeland of low carrying capacity. Less than 1

percent of the cropland is irrigated. Cotton, cantaloupe, and

vegetables are the principal crops. Grain sorghum, alfalfa, and

other feed and forage crops also are grown.

The major soil resource concerns are wind erosion, water

erosion, salinization of irrigated cropland, species diversity, and

undesirable invasive species on rangeland. In this arid or

semiarid MLRA, potential evaporation is often 10 times greater

than precipitation. The soils dominantly have a coarse textured

surface layer and a low content of organic matter, resulting in

little resistance to erosive forces. The vegetative cover on

rangeland is typically sparse, providing tenuous protection

against wind erosion and water erosion.

Conservation practices on rangeland generally include

fencing and development of watering facilities, which facilitate

grazing management systems; brush management, which

removes undesirable and introduced invasive species; and

erosion control, which helps to prevent gullying and

concentrated waterflow.

Conservation practices on irrigated cropland include crop

rotations, which improve the condition of the soils and reduce

the hazard of wind erosion; pest management, which reduces

the extent of weed, insect, and disease infestation; irrigation

water management, which helps to ensure that application

timing and amounts meet crop needs and leaching

requirements; and irrigation delivery systems, which reduce

evaporation, canal seepage losses during conveyance, and

consumption of water by undesirable species, such as saltcedar

and Russian olive. 

113

Figure E-1: Location of Land Resource Region E.

E—Rocky Mountain Range and Forest

Region

This region (shown in fig. E-1) is in Montana (28 percent),

Colorado (20 percent), Idaho (16 percent), Wyoming (13

percent), Utah (10 percent), Oregon (5 percent), Washington (4

percent), and New Mexico (3 percent). It makes up 236,510

square miles (612,875 square kilometers).

This region is characterized mainly by rugged mountains,

but it has some broad valleys and remnants of high plateaus

(fig. E-2). The average annual precipitation ranges from 9

inches (230 millimeters) in some of the valleys to 63 inches

(1,600 millimeters) on some of the mountain peaks. The

average annual temperature ranges from 32 to 50 degrees F (0

to 10 degrees C). The freeze-free period is 65 days or less in the

high mountains, where freezing temperatures occur every

month of the year. Some areas on the highest mountains are

covered by glaciers. The ground is permanently frozen in these

areas. The freeze-free period on the foothills in the southern

part of the region is as long as 190 days.

The total withdrawals of freshwater in this region average

about 11,680 million gallons per day (44,210 million liters per

day). About 10 percent is from ground water sources, and 90

percent is from surface water sources. About 93 percent of the

water is used for irrigation.

The soils in this region are dominantly Alfisols, Entisols,

Inceptisols, and Mollisols. The dominant suborders are Ustepts,

Ustolls, and Xerolls in valleys and on the lower mountain

slopes and Cryalfs and Orthents on the upper mountain slopes

and crests. The soils in the region dominantly have a frigid soil

temperature regime, an ustic soil moisture regime, and mixed

mineralogy.

About 60 percent of the land in this region is federally

owned. The mountain slopes generally are forested, and the

valleys are dominated by shrubs and grasses. Grazing is the

leading land use in the valleys and mountains, but timber

production is important on some of the forested mountain
114 Major Land Resource Areas

Figure E-2: An area of Rocky Mountain National Park in Land Resource Region E.

slopes. Recreation is an important use throughout the region.

Some of the valleys are irrigated, and some are dry-farmed.

Grain and forage for livestock are the main crops. Beans, sugar

beets, peas, and seed crops are grown in areas where soils,

climate, and markets are favorable. The major soil resource

concerns are water erosion; steep slopes; shallow, rocky soils;

and a short growing season. 
of the United States 115

Figure 43A-1: Location of MLRA 43A in Land Resource Region E.

43A—Northern Rocky Mountains

This area (shown in fig. 43A-1) is in Montana (43 percent),

Idaho (34 percent), and Washington (23 percent). It makes up

about 31,435 square miles (81,460 square kilometers). It has no

large cities or towns. U.S. Highway 2 crosses this area in Idaho

and Montana, and U.S. Highway 395 goes to the Canadian

border in the part of the area in Washington. This MLRA is

made up of the Rocky Mountains. It has many national forests,

including the Okanogan and Colville National Forests in

Washington; the Kootenai, Lolo, and Flathead National Forests

in Montana; and the Coeur d’Alene, St. Joe, Clearwater, and

Lolo National Forests in Idaho. The Kaniksu National Forest is

in all three States. Most of Glacier National Park is in the

eastern part of the area, and the Coulee Dam National

Recreation Area is in the western part. The Spokane, Colville,

Coeur d’Alene, Kalispel, and Flathead Indian Reservations

occur in this MLRA.

Physiography

This area is in the Northern Rocky Mountains Province of

the Rocky Mountain System. It is characterized by rugged,

glaciated mountains; thrust- and block-faulted mountains; and

hills and valleys. Steep-gradient rivers have cut deep canyons.

Natural and manmade lakes are common in the area. Franklin D.

Roosevelt Lake, Flathead Lake, and Lake Koocanusa are

examples of the larger lakes. Elevation is about 1,800 to 3,500

feet (550 to 1,065 meters) in the valleys. It is 5,000 to 7,000

feet (1,525 to 2,135 meters) on most mountain peaks, but it is

10,110 feet (3,082 meters) on Kintla Peak, which is in Glacier

National Park, near the Canadian border.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Kootenai-Pend Oreille-Spokane (1701), 67 percent; Upper

Columbia (1702), 18 percent; and Lower Snake (1706), 15

percent. Numerous rivers originate in or flow through this area,

including, from west to east, the Sanpoil, Columbia, Pend

Oreille, Kootenai, St. Joe, Thompson, and Flathead Rivers. The

St. Joe and Middle Fork Flathead Rivers have been designated

as National Wild and Scenic Rivers.

Geology

This area is underlain primarily by stacked slabs of layered

sedimentary bedrock. The bedrock formations range from

Precambrian to Cretaceous in age. The rocks consist of shale,

sandstone, siltstone, limestone, argillite, quartzite, gneiss,

schist, dolomite, basalt, and granite. The formations have been

faulted and stacked into a series of imbricate slabs by regional

tectonic activity. Pleistocene glaciers carved a rugged

landscape that includes sculpted hills and narrow valleys filled

with till and outwash.

Climate

The average annual precipitation is 25 to 60 inches (635 to

1,525 millimeters) in most of this area, but it is as much as 113

inches (2,870 millimeters) in the mountains and is 10 to 15

inches (255 to 380 millimeters) in the western part of the area.

Summers are dry. Most of the precipitation during fall, winter,

and spring is snow. The average annual temperature is 32 to 51

degrees F (0 to 11 degrees C) in most of the area, decreasing

with elevation. In most of the area, the freeze-free period

averages 140 days and ranges from 65 to 215 days. It is longest

in the low valleys of Washington, and it decreases in length
116 Major Land Resource Areas

43B—Central Rocky Mountains

This area (shown in fig. 43B-1) is in Montana (38 percent),

Idaho (32 percent), and Wyoming (30 percent). Also, it is in a

small area in Utah (82 square miles, or 213 square kilometers).

It makes up about 75,915 square miles (196,715 square

kilometers). The towns of Butte, Anaconda, and Deer Lodge,

Montana, Ketchum, Idaho, and Jackson and Thermopolis,

Wyoming, occur in this MLRA. Interstates 90 and 15 cross this

area in Montana. This MLRA is made up of the Rocky

Mountains. It has numerous national forests, including the

Clearwater, Nez Perce, Bitterroot, Salmon, Challis, Payette,

Boise, Targhee, and Sawtooth National Forests in Idaho; the

with elevation. Freezing temperatures occur every month of the

year on high mountains, and some peaks have a continuous

cover of snow and ice.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.3%; ground water, 0.4%

Livestock—surface water, 0.5%; ground water, 3.0%

Irrigation—surface water, 91.2%; ground water, 0.3%

Other—surface water, 2.5%; ground water, 1.8%

The total withdrawals average 355 million gallons per day

(1,345 million liters per day). About 5 percent is from ground

water sources, and 95 percent is from surface water sources.

Moderate precipitation and many perennial streams and lakes

provide ample surface water. About 90 percent of the water used

within this area is diverted from streams to irrigate high

mountain hay meadows. The remaining 10 percent is used

mainly by the mining and timber industries. The surface water

is of good quality. This area supplies water to the adjoining

MLRAs for irrigation and other uses. Springs in the valleys

provide some water for domestic use and for livestock.

Shallow wells in the alluvium and glacial outwash in

intermountain valleys and in some fractured zones in the

bedrock provide water for domestic use and for livestock.

Elsewhere, the supplies of ground water are small and mostly

untapped.

Soils

The dominant soil orders in this MLRA are Andisols,

Inceptisols, and Alfisols. Many of the soils are influenced by

Mount Mazama ash deposits. The soils in the area have a frigid

or cryic soil temperature regime; have an ustic, xeric, or udic

soil moisture regime; and dominantly have mixed mineralogy.

They are shallow to very deep, are very poorly drained to well

drained, and have most of the soil texture classes. The soils at

the lower elevations include Udivitrands (Threebear series),

Vitrixerands (Bonner series), and Haplustalfs (Crow series). The

soils at the higher elevations include Dystrocryepts (Hun

series), Eutrocryepts (Holloway series), Vitricryands (Manley

series), and Haplocryalfs (Meadowport series). Cryorthents,

Cryepts, and areas of rock outcrop are on ridges and peaks

above timberline.

Biological Resources

 This area is in the northern part of the Northern Rocky

Mountains. Grand fir, Douglas-fir, western red cedar, western

hemlock, western larch, lodgepole pine, subalpine fir,

ponderosa pine, whitebark pine, and western white pine are the

dominant overstory species, depending on precipitation,

temperature, elevation, and landform aspect. The understory

vegetation varies, also depending on climatic and landform

factors.

 Some of the major wildlife species in this area are whitetailed deer, mule deer, elk, moose, black bear, grizzly bear,

coyote, fox, and grouse. Fish, mostly in the trout and salmon

families, are abundant in streams, rivers, and lakes.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 3%

Grassland—private, 5%; Federal, 8%

Forest—private, 33%; Federal, 47%

Urban development—private, 1%

Water—private, 1%; Federal, 1%

Other—private, 1%

More than one-half of this area is federally owned and

administered by the U.S. Department of Agriculture, Forest

Service. Much of the privately owned land is controlled by

large commercial timber companies. The forested areas are used

for wildlife habitat, recreation, watershed, livestock grazing,

and timber production. Meadows provide summer grazing for

livestock and big game animals. Less than 3 percent of the area

is cropland.

The major soil resource concerns are water erosion, the

productivity of the soils, and surface compaction. Water

resource concerns include degradation of water quality. Plant

resource concerns are plant productivity, health, and vigor;

noxious and invasive plants; and the hazard of wildfires.

Animal resource concerns are inadequate food, cover, and

shelter.

Conservation practices on forestland generally include

forest site preparation, forest stand improvement, and forest

trails and landings. These practices help to control compaction,

the erosion caused by concentrated flow, and sediment delivery

to streams. 
of the United States 117

Figure 43B-1: Location of MLRA 43B in Land Resource Region E.

gradient rivers have cut deep canyons. Lakes are common,

especially in glaciated areas. Most mountain peaks reach an

elevation of 6,000 to 8,000 feet (1,830 to 2,440 meters), but

peaks exceeding 10,000 feet (3,050 meters) are not uncommon.

The highest points in Montana and Wyoming are in this

MLRA. These are Granite Peak, which reaches an elevation of

12,799 feet (3,902 meters), and Gannett Peak, which reaches an

elevation of 13,804 feet (4,208 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Lower Snake (1706), 19 percent; Upper Snake (1704), 13

percent; Missouri Headwaters (1002), 13 percent; Bighorn

(1008), 12 percent; Kootenai-Pend Oreille-Spokane (1701), 10

percent; Upper Yellowstone (1007), 9 percent; Missouri-Marias

(1003), 8 percent; Middle Snake (1705), 6 percent; Great

Divide-Upper Green (1404), 3 percent; Powder-Tongue (1009),

3 percent; Missouri-Musselshell (1004), 2 percent; Bear (1601),

1 percent; and Saskatchewan (1001), 1 percent. The

Continental Divide runs through this area. The headwaters of

the Columbia and Missouri Rivers are in this MLRA. Rivers

draining the western slope of the Continental Divide in this

area drain into the Pacific Ocean, and rivers on the eastern side

drain into the Gulf of Mexico.

Geology

A variety of rock types from many different geologic eras are

exposed in the Rocky Mountains. The rock types include

igneous, metamorphic, limestone, and sandstone in the Belt

Mountains of Montana; granite in Idaho; and quartzite and

argillite in the Beaverhead Mountains and sedimentary rocks in

the Big Horn Mountains of Wyoming. Glacial till and outwash

are in most mountain valleys. Recent alluvium commonly

covers the glacial deposits on the valley floors.

Climate

The average annual precipitation is 25 to 60 inches (635 to

1,525 millimeters) in most of this area, but it is as much as 121

inches (3,075 millimeters) at the higher elevations west of the

Continental Divide and is 9 to 25 inches (230 to 635

millimeters) in the valleys and lower elevations at the edges of

the area. Summers are typically dry, except for brief but intense

convective thunderstorms that occur during most afternoons in

the mountains. Most of the precipitation during fall, winter, and

spring is snow. The average annual temperature is 24 to 49

degrees F (-4 to 9 degrees C). It is less than 38 degrees F (3

degrees C) in most of the area. The freeze-free period averages

105 days and ranges from 10 to 200 days. It is longest in the

lower valleys and shortest in the mountains. Freezing

temperatures occur every month of the year in the mountains,

and some peaks have a continuous cover of snow and ice.

Lolo, Deerlodge, Beaverhead, Flathead, Helena, Bitterroot, and

Gallatin National Forests in Montana; and the Bighorn,

Shoshone, Bridger, and Teton National Forests in Wyoming.

Many wilderness areas are in these national forests. Three of the

largest are the Selway-Bitterroot, Frank Church River of No

Return, and Sawtooth Wilderness Areas in Idaho. Part of the

Wind River Indian Reservation is in the part of this MLRA in

Wyoming. The Fossil Buttes National Monument and

Yellowstone and Teton National Parks are in this MLRA.

Physiography

Most of this area is in the Northern Rocky Mountains

Province of the Rocky Mountain System. Most of the

southeastern part in Wyoming is in the Middle Rocky

Mountains Province of the same division. This MLRA is

characterized by rugged, glaciated mountains, thrust- and

block-faulted mountains, hills, plateaus, and valleys. Steep-
118 Major Land Resource Areas

43C—Blue and Seven Devils Mountains

This area (shown in fig. 43C-1) is in Oregon (84 percent),

Idaho (11 percent), and Washington (5 percent). It makes up

about 14,000 square miles (36,275 square kilometers). It has no

large cities or towns. Interstate 84 crosses the area from the

southeast corner in Idaho to the northern part of the area in

Oregon. U.S. Highway 395 crosses the western part of the area.

National forests are in most of this area, especially in Oregon.

Some of these forests include the Umatilla, Wallowa-Whitman,

Malheur, and Ochoco National Forests in Oregon and parts of

the Payette and Nez Perce National Forests in Idaho. The forests

have numerous national wilderness areas. The Hells Canyon

National Recreation Area, along the Snake River, is in the

eastern part of this area.

 Physiography

Most of this area is in the Blue Mountain Section of the

Columbia Plateaus Province of the Intermontane Plateaus. The

western end in Oregon and the northern end in Washington and

Idaho are in the Walla Walla Plateau Section of the same

province and division. The southernmost part in Oregon

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 1.0%; ground water, 0.7%

Livestock—surface water, 0.3%; ground water, 1.4%

Irrigation—surface water, 78.0%; ground water, 12.8%

Other—surface water, 3.7%; ground water, 2.1%

The total withdrawals average 1,415 million gallons per day

(5,355 million liters per day). About 17 percent is from ground

water sources, and 83 percent is from surface water sources.

Moderate precipitation and many perennial streams and lakes

provide ample surface water. About 75 percent of the water used

within this area is diverted from streams and used to irrigate hay

meadows. Some of the water is used by the mining and logging

industries or for public supplies in tourist centers. The surface

water is of good quality. This area supplies water to the

adjoining MLRAs for irrigation and other uses. Springs in the

valleys provide some water for domestic use and for livestock.

Shallow wells in the alluvium and glacial outwash on valley

floors provide water for domestic use, livestock, and some

irrigation. Elsewhere, the supplies of ground water are small

and mostly untapped.

Soils

The dominant soil orders in this area are Inceptisols,

Alfisols, and Mollisols. The soils in the area dominantly have

a frigid or cryic soil temperature regime and an ustic, udic, or

xeric soil moisture regime. Soils on mountain side slopes and

ridges formed in colluvium, residuum, and glacial till and have

mixed mineralogy. The dominant suborders are Cryepts

(Jughandle and Garlet series), Ustepts (Kadygulch and

Winkler series), Ustalfs (Yreka and Mocmont series), Cryalfs

(Worock and Sapphire series), Cryolls (Starley and Povey

series), and Xerepts (Packerjohn series). Areas of rock outcrop

and rubble land are on ridges and peaks above timberline.

Most of the soils are skeletal and are medium textured to

coarse textured.

Biological Resources

This area supports coniferous forests. Forests of ponderosa

pine, lodgepole pine, Douglas-fir, subalpine fir, and spruce are

common. Alpine grasses, forbs, and shrubs and scattered stands

of subalpine fir, spruce, and whitebark pine occur at high

elevations.

Some of the major wildlife species in this area include

elk, mule deer, white-tailed deer, moose, grizzly bear, black

bear, mountain lion, bobcat, lynx, bighorn sheep, mountain

goat, coyote, gray wolf, mountain grouse, and numerous

songbirds.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 1%

Grassland—private, 14%; Federal, 51%

Forest—private, 6%; Federal, 25%

Water—private, 1%; Federal, 1%

Other—private, 1%

More than three-fourths of this area is federally owned and

administered by the U.S. Department of Agriculture, Forest

Service. Large commercial timber companies own most of the

private land in the area. All of the forested areas are used for

wildlife habitat, recreation, watershed, and timber production.

Meadows on the upper mountain slopes and crests above

timberline provide summer grazing for livestock and big game

animals. Less than 1 percent of the MLRA is cropland.

The major soil resource concerns are water erosion, the

productivity of the soils, and surface compaction. Water

resource concerns include degradation of water quality. Plant

resource concerns are plant productivity, health, and vigor;

noxious and invasive plants; and the hazard of wildfires.

Animal resource concerns are inadequate food, cover, and

shelter.

Conservation practices on forestland generally include

forest stand improvement, erosion control, and firebreaks.

Control of noxious and invasive plants is needed. 
of the United States 119

Figure 43C-1: Location of MLRA 43C in Land Resource Region E.

percent; Middle Snake (1705), 18 percent; and Oregon Closed

Basins (1712), 8 percent. The headwaters for the John Day,

Grande Ronde, and Umatilla Rivers are in this area. The Salmon

River crosses the part of this area in Idaho just upstream from its

confluence with the Snake River. The Minam and Rapid Rivers,

in the eastern part of the area, have been designated as National

Wild and Scenic Rivers.

Geology

This area consists of a complex collection of bedrock types

that have been faulted and uplifted. These bedrock types

include sedimentary, metasedimentary, and volcanic rocks.

They range from Mesozoic limestones to Cenozoic volcanics.

The rocks consist of limestone, serpentine, greenstone

(metamorphic lava), schist, granite, andesite, and basalt. The

Wallowa and Seven Devils Mountains are made up dominantly

of greenstone (metamorphosed lavas) with some peaks and

ridges of limestone. The Wallowa Mountains and the northern

end of the Elkhorn Mountains have a core of granite. The

Strawberry Mountains are dominantly andesite. The northern

one-third of the Blue Mountains has Columbia River Basalt.

The lower elevations include Columbia River Basalt and the

Clarno and John Day Formations. Pleistocene glaciation has

sculpted the higher peaks and filled many of the valleys with

glacial till and outwash.

Climate

The average annual precipitation in most of this area is 12 to

43 inches (305 to 1,090 millimeters), but it can be as much as

82 inches (2,085 millimeters) in the mountains. Summers are

dry, except for occasional high-intensity, convective

thunderstorms, especially at the higher elevations. Most of the

precipitation, in the form of snow, occurs during the fall, winter,

and spring. The average annual temperature generally is 34 to

45 degrees F (1 to 7 degrees C), decreasing with elevation. It

can be as high as 52 degrees F (11 degrees C) in some of the

deeper canyons. The freeze-free period averages 140 days and

ranges from 55 to 225 days. The shortest freeze-free periods

occur in the mountains, and the longest occur in some of the

deeper canyons. Freezing temperatures occur every month of

the year in the mountains, and some of the highest peaks have a

continuous cover of snow and ice.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 0.5%; ground water, 0.5%

Irrigation—surface water, 81.0%; ground water, 7.1%

Other—surface water, 10.1%; ground water, 0.7%

extends into the Harney Section and the southern part in Idaho

extends into the Payette Section of the same province and

division. The middle part of the area in Idaho is in the Northern

Rocky Mountains Province of the Rocky Mountain System.

The Snake River and the Central Rocky and Blue Mountain

Foothills separate the Idaho and Oregon parts of this MLRA.

Thrust- and block-faulted mountains and deep canyons

characterize this area. The central and eastern parts of the area

have the steepest mountain slopes, whereas the western and

northern parts have more gently rolling mountains. The highest

peaks have been sculpted by alpine glaciation, leaving steep

slopes and sharp crests. Most of the area is cut by narrow

valleys with steep gradients. Some of the larger rivers draining

the mountains have wide valley floors. Lakes are common,

especially in glaciated areas. Elevation is mainly 1,300 to

7,900 feet (395 to 2,410 meters) but is more than 9,800 feet

(2,990 meters) at the top of Mount Sacajawea and the Matterhorn.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Middle Columbia (1707), 40 percent; Lower Snake (1706), 34
120 Major Land Resource Areas

The total withdrawals average 495 million gallons per day

(1,875 million liters per day). About 8 percent is from ground

water sources, and 92 percent is from surface water sources.

Moderate precipitation and many perennial streams and lakes

provide ample surface water. Streams and reservoirs supply

water to the adjoining MLRAs for irrigation and other uses.

Springs in the valleys provide water for domestic use and for

livestock. The surface water is of very good quality. Adequate

waterflow and water quality are needed year-round for the local

fish populations and for anadromous fish migration and

spawning.

Ground water occurs in two aquifers in this MLRA. One is in

the basin fill and alluvial aquifer occurring in most stream and

river valleys throughout the area. Water from this aquifer has a

median level of total dissolved solids of 170 parts per million

(milligrams per liter) and is moderately hard. It is generally of

very good quality and is used for domestic supply, livestock,

and some irrigation. The second aquifer is the basalt flows from

the Columbia River and Idaho Batholiths. Interbedded layers of

sediments and pyroclastics between the basalt flows and joints,

bedding planes, and rubble zones within the basalt itself

contain water. The ground water in the basalt has a median

level of total dissolved solids of 230 parts per million

(milligrams per liter) and is moderately hard. It is generally of

very good quality and is used for domestic supply, livestock,

and irrigation. The supplies of ground water are minimal and

mostly untapped in the steep mountains.

Soils

The dominant soil orders in this MLRA include Mollisols

and Andisols. The soils in the area have a mesic soil

temperature regime at the lower elevations and a frigid or cryic

soil temperature regime at the higher elevations. They have a

xeric or udic soil moisture regime. Most of the soils have a

component of volcanic ash from Mount Mazama, which is the

present-day Crater Lake, in south-central Oregon. The soils are

shallow to very deep, are very poorly drained to well drained,

and have most of the soil texture classes.

The soils at the lower elevations in the drier parts of the area

are typically Argixerolls, Palexerolls, and Haploxerolls with

smectitic mineralogy and are either fine textured (Hankins

series) or clayey-skeletal (Yawkey series). The soils at the

slightly higher elevations or in the more protected areas retain

the influence of volcanic ash and are Vitrandic Haploxerolls

(Egyptcreek series) or Vitrandic Argixerolls (Klickson series).

The volcanic plateaus in the northeastern part of the area have

Argialbolls (Cowsly series). The soils in the meadows and on

bottom lands are Fluvaquentic Haploxerolls (Damore series)

and Cumulic Cryaquolls (Silvies series). Cryorthents, Cryepts,

and areas of rock outcrop are on ridges and peaks above

timberline.

Biological Resources

This area has a highly diverse biological population. The

distribution of vegetation is related to climate, especially the

effective precipitation and aspect. At the lower elevations,

which are the driest and warmest, the south aspects are typified

by an overstory of western juniper and a sagebrush-bunchgrass

plant community in the understory. The north and east aspects

at these lower elevations support ponderosa pine with an

understory of either bunchgrasses or pinegrass. At the slightly

higher elevations, there is an increase in precipitation and the

vegetation is dominated by an overstory of Douglas-fir with an

understory of either snowberry or ninebark. At the high

elevations, subalpine fir, Engelmann spruce, and whitebark

pine are evident. Lodgepole pine and western larch are seral

species, especially in the areas where grand fir is the potential

overstory species. The understory in the cooler, more moist

areas is typically Clintonia and big huckleberry. Grasses, forbs,

and sedges dominate the high alpine meadows.

Some of the major wildlife species in this area are elk,

mule deer, black bear, mountain lion, bobcat, bighorn sheep,

mountain goat, coyote, grouse, and songbirds. Streams

provide habitat for several species of trout. Some of the major

streams provide valuable spawning grounds for salmon and

steelhead.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 1%

Grassland—private, 13%; Federal, 4%

Forest—private, 20%; Federal, 57%

Water—Federal, 1%

Other—Federal, 4%

This area is used primarily for timber production, livestock

grazing, wildlife habitat, recreation, and watershed. Only a very

small area in the valleys is cropland, most of which is irrigated.

A large percentage of the area is federally owned and

administered by the U.S. Department of Agriculture, Forest

Service.

The major soil resource concerns are erosion, surface

compaction, and sedimentation of streams. The quality of

surface water resources also is a major concern.

Conservation practices on forestland generally include

forest site preparation, forest stand improvement, and forest

trails and landings. These practices help to control surface

compaction, the erosion caused by concentrated flow, and

sediment delivery to streams. Prescribed grazing is an important

conservation practice in areas that are used for livestock

grazing.

Conservation systems on cropland are used to control
of the United States 121

erosion and preserve water quality. They generally include such

practices as cover crops, conservation crop rotation, crop

residue management, waste utilization, nutrient management,

pest management, filter strips, grassed waterways, and irrigation

water management.

 Conservation practices on pasture and hayland generally

include prescribed grazing, forage harvest management,

nutrient management, waste utilization, and filter strips. These

practices protect water quality and aquatic habitat for fish and

wildlife by reducing the movement of nutrients and pesticides

to surface water and ground water. 

Figure 44-1: Location of MLRA 44 in Land Resource Region E.

44—Northern Rocky Mountain Valleys

This area (shown in fig. 44-1) is in Montana (79 percent),

Idaho (13 percent), and Washington (8 percent). It makes up

about 12,830 square miles (33,245 square kilometers). The

cities of Spokane, Washington, Coeur d’Alene, Idaho, and

Kalispell, Missoula, Bozeman, and Helena, Montana, are in this

MLRA. Interstate 90 connects Spokane and Bozeman, and

Interstate 15 runs north and south through the eastern part of

the MLRA. Although most of the valley floors are privately

owned, the valley borders commonly are part of numerous

national forests, including the Kaniksu and Colville National

Forests in Washington and Idaho and the Kootenai, Lolo, and

Beaverhead National Forests in Montana.

Physiography

This area is in the Northern Rocky Mountains Province of

the Rocky Mountain System. It is an area of deeply dissected

mountain valleys. The deep valleys are typically bordered by

mountains trending north to south. In the valleys, nearly level,

broad flood plains are bordered by gently sloping to strongly

sloping terraces and alluvial fans. In many areas, the valleys

have been modified somewhat by glaciation. In the northern

part of the area, glacial debris dams created lakes in the valleys

for a period of time in the past. In these areas, lacustrine

sediments cover much of the valley floors. Elevation ranges

from 1,750 feet (535 meters) to as much as 6,900 feet (2,105

meters). The highest valleys are in the part of this MLRA in

southwestern Montana.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Kootenai-Pend Oreille-Spokane (1701), 49 percent; Missouri

Headwaters (1002), 35 percent; Missouri-Marias (1003); 9

percent; and Upper Yellowstone (1007), 7 percent. Numerous

rivers run through the different mountain valleys in this MLRA.

The Spokane River connects Spokane, Washington, and Coeur

d’Alene, Idaho. The Kootenai, Bitterroot, Clark’s Fork, and

Flathead Rivers are in the larger valleys in Montana. The

headwaters of the Missouri River at historic Three Forks,

Montana, occur in this MLRA. The Madison, Jefferson, and

Gallatin Rivers join here to form the Missouri River, the largest

tributary to the Mississippi River.

Geology

The mountains bordering the valleys in this MLRA are

uplifted fault blocks that have been recently glaciated. Streams

eroding the mountains have created alluvial fans at the edges of

the valleys and have deposited silt, sand, and gravel as alluvial

valley fill throughout the area. Modern streams have reworked

the valley fill deposits, creating terraces and flood plains at the

lower elevations in the valleys. Glacial lake deposits occur in

some of the valleys in the northwestern part of the MLRA.

Climate

The average annual precipitation is 12 to 16 inches (305 to

405 millimeters) in most of this area, but it is about 9 inches

(230 millimeters) in parts of Montana and is as much as 44

inches (1,120 millimeters) in northern Idaho. Precipitation is
122 Major Land Resource Areas

fairly evenly distributed throughout fall, winter, and spring but

is low in summer. Rainfall occurs as high-intensity, convective

thunderstorms during spring and fall. Most of the precipitation

in winter is snow. The average annual temperature is 33 to 49

degrees F (1 to 9 degrees C). The freeze-free period averages

120 days and ranges from 50 to 185 days in much of the area. It

is 80 days or less at the highest elevations and 130 days or

more at the lowest.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.8%; ground water, 0.7%

Livestock—surface water, 0.2%; ground water, 0.2%

Irrigation—surface water, 94.3%; ground water, 3.3%

Other—surface water, 0.5%; ground water, 0.2%

The total withdrawals average 4,390 million gallons per day

(16,615 million liters per day). About 4 percent is from ground

water sources, and 96 percent is from surface water sources.

Precipitation is adequate for some dryfarming at the higher

elevations and throughout the part of this MLRA in northern

Idaho. Perennial streams flowing into the area from surrounding

mountains are the principal water sources. The amount of water

usually is adequate but depends on snow accumulation in the

mountains. This water is of good quality, and its use is not

limited.

Ground water of very good quality is abundant in the deeper,

unconsolidated alluvial valley fill. Some of this water is used

for irrigation. The median value of total dissolved solids in the

water is about 250 parts per million (milligrams per liter). The

calcium-bicarbonate type of water is hard or very hard. The

ground water in the glacial lake deposits in the valleys in the

northwestern part of the MLRA appears to be very similar in

quality to the ground water in the alluvial valley fill.

The carbonate rocks in the Madison Group are considered to

be an aquifer on the eastern margins of this area. The use of this

bedrock aquifer is limited, however, because deep wells are

required to reach the aquifer. Beneath the valley floors, the

water quality in the Madison Group is marginal for most uses.

The median value of total dissolved solids exceeds 1,600 parts

per million (milligrams per liter), and the water has very high

levels of sulfate. This calcium-sulfate type of water is very hard.

Near the recharge zones in the mountains, water quality is much

better.

Soils

The dominant soil orders in this MLRA are Inceptisols,

Mollisols, and Andisols. The soils in the area dominantly have

a frigid soil temperature regime at the lower elevations and a

cryic soil temperature regime at the higher elevations, an ustic

or xeric soil moisture regime, and mixed mineralogy. They

generally are very deep, well drained, and loamy or loamyskeletal. Calciustepts (Amesha, Brocko, Crago, Kalsted,

Musselshell, and Scravo series) formed in mixtures of

alluvium, colluvium, and eolian sediments on alluvial fans,

stream terraces, plains, and hills. Haploxerolls (Bigarm series)

formed in alluvium, colluvium, and till on stream terraces,

alluvial fans, and hills. Argiustolls (Nuley series) formed in

residuum on hills and plains. Calciustolls (Trimad series) and

Argiustolls (Varney series) formed in alluvium on alluvial fans,

terraces, and hills. Vitrixerands (Bonner and Eloika series)

formed in glacial outwash or ablation till on stream terraces,

terrace escarpments, and till plains. Haploxerepts (Avonville

series) formed in glacial outwash on outwash plains and

outwash terraces.

Biological Resources

This area supports conifer forests and grassland vegetation.

Bluebunch wheatgrass, rough fescue, Idaho fescue, and bearded

wheatgrass are the major species on the grassland in the valleys

and foothills. Douglas-fir, ponderosa pine, grand fir, western red

cedar, western hemlock, pinegrass, common snowberry, mallow

ninebark, and white spirea are the major forest species.

Some of the major wildlife species in this area are elk, mule

deer, white-tailed deer, antelope, coyote, bobcat, badger, beaver,

mink, otter, muskrat, cottontail, ground squirrel, pheasant, gray

partridge, sharp-tailed grouse, sage grouse, blue grouse, spruce

grouse, and ruffed grouse. The species of fish in the area

include rainbow, brown, and brook trout.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 17%

Grassland—private, 45%; Federal, 8%

Forest—private, 14%; Federal, 3%

Urban development—private, 6%

Water—private, 4%; Federal, 1%

Other—private, 2%

More than one-half of this area is in farms and ranches. As

much as one-third of the land in some valleys is irrigated.

Potatoes, sugar beets, and peas are important cash crops, but a

larger acreage is used for hay, grain, or pasture for livestock

feed. In areas where precipitation is adequate, dry-farmed wheat

is grown. About one-half of the area is rangeland with native

grasses and shrubs. Beef cattle and sheep are the principal kinds

of livestock, but dairying is an important enterprise near the

larger towns. Much of the part of this MLRA in northern Idaho

is forested. Elsewhere, many steep and stony soils are forested.
of the United States 123

These forests are of value to the lumber industry and also are

grazed.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and

productivity of the soils, and management of soil moisture.

Because of freezing and thawing, the soils are susceptible to

erosion. Water resource concerns include failure to meet plant

needs because of the inefficient use of water on irrigated

cropland. They also include excessive amounts of pesticides,

nutrients, and organic material in surface and ground waters.

Plant resource concerns are deterioration of plant condition,

productivity, health, and vigor and noxious and invasive

plants. Animal resource concerns are inadequate food, cover,

and shelter.

The most important conservation practices on rangeland are

prescribed grazing, fencing, and development of watering

facilities. Establishment of food plots and rangeland

improvement practices benefit wildlife. Establishment of early

and late season pastures supplements forage production and

keeps livestock off rangeland during critical growth periods.

Conservation practices on cropland generally include crop

residue management, minimum tillage, cover crops, nutrient

management, and pest management. The practices on irrigated

cropland include irrigation water management, irrigation water

delivery systems, and on-farm irrigation practices, such as

sprinklers. Noxious and invasive plants can be controlled by

pest management and prescribed grazing. 

Figure 46-1: Location of MLRA 46 in Land Resource Region E.

46—Northern Rocky Mountain Foothills

This area is entirely in Montana (fig. 46-1). It makes up

about 15,100 square miles (39,130 square kilometers).

Interstate 90 crosses the southern tip of the area, and Interstate

15 parallels the Missouri River where the area pinches down to

a narrow section bisecting the northern and southern halves of

the MLRA. This MLRA includes parts of the Lewis and Clark,

Gallatin, and Custer National Forests. The Crow and Blackfeet

Indian Reservations are in the southern and northern ends of

the MLRA, respectively.

Physiography

The north quarter of this MLRA is in the Missouri Plateau,

Glaciated, Section of the Great Plains Province of the Interior

Plains. The rest of the MLRA is in the Missouri Plateau,

Unglaciated, Section of the same province and division. These

two sections have similar landforms. The glaciated parts in the

north are on the extreme western edge of the southern extent of

continental glaciation, so few glacial landforms and minor

glacial deposits occur in the area. The foothills east of the

Northern Rocky Mountains are on an old plateau of uplifted

marine sediments. The rugged hills and low mountains are cut

by many narrow valleys that have steep gradients. Broad flood

plains and fans border a few of the major rivers. Elevation

ranges from 3,600 to 5,900 feet (1,100 to 1,800 meters) in the

northern part of the area, increasing gradually to 5,900 to 7,870

feet (1,800 or 2,400 meters) in the southern part.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Missouri-Marias (1003), 37 percent; Missouri-Musselshell

(1004), 35 percent; Upper Yellowstone (1007), 11 percent; Milk

(1005), 8 percent; Bighorn (1008), 7 percent; and

Saskatchewan (1001), 2 percent. The Missouri River bisects

this area. Numerous tributary streams to the Missouri River

cross the area. Clark’s Fork of the Yellowstone River flows north

across the southern part of the area on its way to join the

Yellowstone River just outside this MLRA.

Geology

Almost all of this area is characterized by Upper Cretaceous

to Jurassic marine sediments of the Montana and Colorado
124 Major Land Resource Areas

Groups and the Kootenai Formation. These rocks are primarily

sandstones and shales with some layers of chalk and

conglomerate. Dinosaur bones have been found in some of the

shales. Tertiary continental sediments are in the southern part of

the area. These river-laid sediments contain some coal. The

Madison Group occurs at the edges of the central and southern

parts of the MLRA, where faults have brought older bedrock

units to the surface.

Climate

The average annual precipitation is 12 to 20 inches (305 to

510 millimeters) in most of this area. It is as high as 53 inches

(1,345 millimeters), however, at the highest elevations and is as

low as 8 inches (205 millimeters) in some basins. Most of the

rainfall occurs as high-intensity, convective thunderstorms. In

the northern part of the area, the minimum precipitation occurs

in spring. In the southern part, however, precipitation is lowest

in early summer. Winter precipitation is snow. The average

annual temperature is 34 to 48 degrees F (1 to 9 degrees C). The

town of Cut Bank, known for having the coldest temperature in

the continental United States on many winter days, is in the

northern part of the area. The freeze-free period averages 125

days and ranges from 70 to 180 days, decreasing in length with

elevation and from south to north.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 0.3%; ground water, 0.1%

Irrigation—surface water, 98.4%; ground water, 0.6%

Other—surface water, 0.5%; ground water, 0.2%

The total withdrawals average 865 million gallons per day

(3,275 million liters per day). About 1 percent is from ground

water sources, and 99 percent is from surface water sources. The

amount of precipitation is too low for good crop growth in

some parts of this MLRA. In other parts, however, it is adequate

for grain farming and forage production. The major rivers

provide most of the water for irrigation, but small streams

furnish local supplies. The surface water generally is of good

quality and is suitable for most uses.

Ground water is abundant in the alluvial fill in some valleys.

It is of good quality and is suitable for all uses. Mesozoic

aquifers, Eagle Sandstone, and the Kootenai Formation occur in

this area, but they have little or no ground water. The Madison

Group aquifer occurs at depth in this area. Although the

quantity of water is not a problem in the Madison Group, deep

wells are required and the water quality generally is poor.

Soils

The dominant soil orders in this MLRA are Mollisols and

Entisols. The soils in the area dominantly have a frigid soil

temperature regime, an ustic soil moisture regime, and mixed or

smectitic mineralogy. They are shallow to very deep, generally

well drained, and loamy or clayey. Argiustolls formed in

residuum or colluvium on uplands (Absarokee and Reeder

series), in alluvium and/or colluvium on alluvial fans and

terraces (Danvers and Fairfield series), and in till on till plains

and hills (Vida series). Haplustolls (Castner and Winifred series)

and Ustorthents (Cabba and Wayden series) formed in residuum

and/or colluvium on hills, plains, and mountains. Calciustolls

(Judith, Rothiemay, and Windham series) formed in alluvium

and colluvium on alluvial fans and terraces.

Biological Resources

This area supports grass vegetation in the valleys and

foothills and forest vegetation at the higher elevations.

Bluebunch wheatgrass, rough fescue, Idaho fescue, and

western wheatgrass are the major grass species. Ponderosa

pine, limber pine, Rocky Mountain juniper, common

snowberry, and skunkbrush sumac are the dominant species

in forested areas.

Some of the major wildlife species in this area are whitetailed deer, mule deer, pronghorn antelope, coyote, badger,

raccoon, fox, skunk, ground squirrel, pocket gopher, cottontail

rabbit, ring-necked pheasant, gray partridge, sharp-tailed

grouse, and sage grouse.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 24%

Grassland—private, 65%; Federal, 4%

Forest—private, 4%

Urban development—private, 1%

Water—private, 1%

Other—private, 1%

Less than 5 percent of this area is federally owned. The rest

is in farms and ranches. Nearly 70 percent of the area is

rangeland with short and mid grasses and some shrubs. Many of

the valleys are irrigated, but they make up only 1 or 2 percent

of the total area. Grain and forage for livestock are the main

crops, but potatoes, sugar beets, peas, and some other crops are

grown in the warmer valleys. About one-fifth of the area, mainly

along the northeastern side, is used for dry-farmed wheat. Some

of the highest hills are forested.
of the United States 125

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and

productivity of the soils, management of soil moisture, and

control of saline seeps. Water resource concerns include failure

to meet plant needs because of the inefficient use of water on

irrigated cropland. They also include excessive amounts of

pesticides, nutrients, and organic material in surface and

ground waters. Plant resource concerns are deterioration of

plant condition, productivity, health, and vigor; noxious and

invasive plants; and the hazard of wildfires. Animal resource

concerns are inadequate food, cover, and shelter.

The most important conservation practices on rangeland

are prescribed grazing, fencing, and development of watering

facilities. Establishment of food plots and rangeland

improvement practices benefit wildlife. Establishment of

early and late season pastures supplements forage production

and keeps livestock off rangeland during critical growth

periods.

Conservation practices on cropland generally include crop

residue management, minimum tillage, cover crops, wind

stripcropping, nutrient management, soil salinity management,

and pest management. The practices on irrigated cropland

include irrigation water management, irrigation water delivery

systems, and on-farm irrigation practices, such as sprinklers.

Noxious and invasive plants can be controlled by pest

management and prescribed grazing.

Conservation practices on forestland include forest stand

improvement and firebreaks. These practices reduce the hazard

of wildfires and improve forest growth, quality, health, and

productivity. 

Figure 47-1: Location of MLRA 47 in Land Resource Region E.

47—Wasatch and Uinta Mountains

This area (shown in fig. 47-1) is in Utah (86 percent),

Wyoming (8 percent), Colorado (4 percent), and Idaho (2

percent). It makes up about 23,825 square miles (61,740

square kilometers). Coalville, Heber City, Panguitch, and

Park City, Utah, and Evanston, Wyoming, are in this MLRA.

Interstates 84, 80, and 70 cross this area. Most of Zion and

Bryce Canyon National Parks and Cedar Breaks and

Dinosaur National Monuments are in this area. This MLRA

includes the Uinta Wilderness in Utah and numerous wilderness

study areas. It has numerous national forests, including the

Ashley, Caribou, Dixie, Fishlake, Manti-La Sal, Uinta, and

Wasatch-Cache National Forests. The northern part of the

Uinta-Ouray Indian Reservation and the southern part of the

Flaming Gorge National Recreation Area in Utah are in this

area. Most of the Paiute Indian Reservation is in the southern

part of the area.

Physiography

The northern half of this area is in the Middle Rocky

Mountains Province of the Rocky Mountain System. The

southern half is in the High Plateaus of Utah Section of the

Colorado Plateaus Province of the Intermontane Plateaus.

Parts of the western edge of this MLRA are in the Great Basin

Section of the Basin and Range Province of the Intermontane

Plateaus. The MLRA includes the Wasatch Mountains, which

trend north and south, and the Uinta Mountains, which trend

east and west. The steeply sloping, precipitous Wasatch

Mountains have narrow crests and deep valleys. Active

faulting and erosion are a dominant force in controlling the

geomorphology of the area. The Uinta Mountains have a

broad, gently arching, elongate shape. Structurally, they

consist of a broadly folded anticline that has an erosionresistant quartzite core. Some of the mountain areas that are
126 Major Land Resource Areas

above 7,500 feet (2,285 meters) and all of the areas above

10,000 feet (3,050 meters) have been subject to alpine or

mountain glaciation. There are arêtes, horns, cirques, all

types of moraines, and outwash features. In the southern part

of the MLRA, there are rolling mountains and thrust-faulted

plateaus that are broad, gently sloping surfaces with steep side

slopes that have deep canyons cut into them. The Wasatch and

Uinta Mountains have an elevation of 4,900 to about 13,500

feet (1,495 to 4,115 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Escalante Desert-Sevier Lake (1603), 25 percent; Great Salt

Lake (1602), 18 percent; Lower Green (1406), 18 percent; Bear

(1601), 13 percent; Great Divide-Upper Green (1404), 11

percent; Upper Colorado-Dirty Devil (1407), 9 percent; Lower

Colorado-Lake Mead (1501), 4 percent; and White-Yampa

(1405), 2 percent. The Duchesne River and many other

tributaries to the Green River run through the northeastern part

of the MLRA. The Sevier River is in the central and southern

parts. The headwaters of the Virgin River are in the southern part.

Geology

The mountains in this area are primarily fault blocks that

have been tilted up. Alluvial fans at the base of the mountains

are recharge zones for the basin fill aquifer and are significant

sources of sand and gravel for construction. An ancient

shoreline of historic Lake Bonneville is evident on the

footslopes along the western edge of the area. Rocks exposed in

the mountains are mostly Mesozoic and Paleozoic sediments,

but Precambrian rocks are exposed in the Uinta Mountains. The

Uinta Mountains are among the few ranges in the United States

that are oriented west to east. Younger igneous rocks (ash and

lava) are throughout the area. Lava-capped mesas are common

in the southern part of the area. The southern Wasatch

Mountains consist of Tertiary volcanic rocks occurring as

extrusive lava and intrusive crystalline rocks. Eroded volcanic

cones are in the southwestern part of the MLRA.

Climate

The average annual precipitation in most of this area is 15 to

30 inches (380 to 760 millimeters). In some valleys between

mountain ranges in the southern part of the area, in Utah, it is 6

to 10 inches (150 to 255 millimeters). It is 10 to 15 inches (255

to 380 millimeters) in some areas in the southern part of the

MLRA (in Utah) and in the northeastern part of the MLRA, in

Colorado and Wyoming. It can be as much as 73 inches (1,855

millimeters) at the higher elevations. In the northern and

western parts of the area, peak precipitation occurs in the winter

months. The southern and eastern parts have a greater incidence

of high-intensity summer thunderstorms; hence, a significant

amount of the precipitation occurs during summer. The higher

elevations receive significant amounts of snowfall each year.

The average annual temperature is 30 to 58 degrees F (-1 to 15

degrees C). The freeze-free period averages 140 days and ranges

from 60 to 220 days, generally decreasing in length with

elevation.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.1%; ground water, 0.1%

Livestock—surface water, 4.1%; ground water, 1.0%

Irrigation—surface water, 69.7%; ground water, 17.4%

Other—surface water, 3.7%; ground water, 4.0%

The total withdrawals average 380 million gallons per day

(1,440 million liters per day). About 22 percent is from ground

water sources, and 78 percent is from surface water sources.

Streams, lakes, and ground water supply enough water for the

grazing and forestry enterprises in most of the area. Reservoirs

in the mountains of this area store water for downstream use.

The mountain water is of excellent quality. Perennial streams

from the Wasatch Mountains in this area provide irrigation and

municipal and industrial water for most of the population in

Utah. The Green and Sevier Rivers provide irrigation water

away from the population centers. Almost 99 percent of the

flow within the Sevier River basin in the southern end and

middle of this MLRA is used for irrigation and some public

supply. Salinity in irrigation return flows is a problem in the

rivers in the southern part of the area.

Ground water in this area is primarily in the unconsolidated

deposits of sand and gravel filling the major river valleys in the

interior of the area and similar deposits filling the basins on the

western edge of the area. Water from these aquifers is very hard

but typically contains less than 1,000 parts per million

(milligrams per liter) total dissolved solids. Low levels of salts

occur in the ground water closest to the recharge areas along

the base of the mountains, while briny water occurs in the

deeper parts of these deposits.

Soils

The dominant soil orders in this MLRA are Aridisols,

Entisols, Inceptisols, and Mollisols. The soils in the area

dominantly have a frigid soil temperature regime on plateaus

and the lower mountain slopes and a cryic soil temperature

regime at the higher elevations. They have a mesic soil

temperature regime at the lowest elevations, on south-facing

slopes, and in some of the valleys in southern Utah. The soil

moisture regime is typically xeric in the northern part of the

area but grades to ustic in the extreme eastern and southern
of the United States 127

parts. Mineralogy is typically mixed. The soils are very shallow

to very deep, generally well drained, and loamy or loamyskeletal.

Haplocalcids (Amtoft and Hiko Peak series) formed in slope

alluvium, colluvium, and residuum derived from sedimentary

and igneous rocks on mountains and hills. Torriorthents (Tebbs

and Alldown series) formed in alluvium and slope alluvium on

alluvial fans and valley floors. Haploxerolls (Agassiz series)

and Argicryolls (Skutum series) formed in slope alluvium,

colluvium, and residuum on mountain slopes. Calcixerolls

(Lizzant series) formed in slope alluvium or colluvium on fan

remnants and hillslopes. Argixerolls (Ant Flat, Henefer, and

Yeates Hollow series) formed in slope alluvium or colluvium on

fan terraces, piedmonts, and hills. Palecryolls (Lucky Star

series) formed in till or colluvium on moraines or mountain

slopes.

Biological Resources

This area supports conifer, aspen, grass, mountain shrub, and

sagebrush-grass vegetation. The composition of the vegetation

varies with elevation. The zone above an elevation of about

13,000 feet (3,965 meters) supports alpine meadow. Coniferous

forests of Engelmann spruce, white fir, subalpine fir, and Rocky

Mountain Douglas-fir dominate the mid to high elevations. The

most common understory plants in these forests are Oregongrape, myrtle pachystima, and heartleaf arnica. The part of the

MLRA in the Uinta Mountains includes significant amounts of

lodgepole pine, and the southern part of the Wasatch

Mountains includes significant amounts of ponderosa pine.

Forests of quaking aspen commonly have an understory that

includes blue wildrye, mountain brome, Fendler meadowrue,

and aspen peavine. Bluebunch wheatgrass, bearded wheatgrass,

blue wildrye, mountain brome, and numerous forbs grow in the

understory in areas of Gambel oak, curl-leaf and birchleaf

mountain mahogany, snowberry, and serviceberry. Big

sagebrush and bluebunch wheatgrass are the dominant species

in the sagebrush-grass plant communities that are common at

the lowest elevations. The abundance of warm-season

herbaceous species increases significantly in the southern part

of the MLRA.

Some of the major wildlife species in this area are moose,

elk, mule deer, coyote, red fox, bobcat, beaver, porcupine,

snowshoe hare, jackrabbit, sage grouse, chukar, sharp-tailed

grouse, gray partridge, ruffed grouse, and blue grouse. The

species of fish in the area include rainbow trout, brown trout,

brook trout, cutthroat trout, catfish, and sucker.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 2%

Grassland—private, 25%; Federal, 35%

Forest—private, 7%; Federal, 25%

Urban development—private, 1%

Water—private, 1%; Federal, 1%

Other—private, 1%; Federal, 2%

Less than one-third of this area is in farms and ranches.

The rest of the area generally is federally owned. Grassland and

woodland are grazed in summer. Some dense forests are

on moist sites. Recreation and mining are important land uses.

A few valleys are irrigated. Forage for livestock is the main

crop.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the productivity of the soils, and

maintenance of the quality of surface water. Maintaining a

vegetative cover, maintaining the content of organic matter,

and preventing excessive compaction are important. Mass

movement of the soils also is a concern. Proper grazing use is a

concern on grazing lands. In timbered areas, the primary

concerns during timber harvesting are controlling erosion

along roads and skid trails and minimizing the compaction

caused by harvesting equipment.

Conservation practices on rangeland generally include

brush management, rangeland seeding, prescribed grazing,

prescribed burning, fencing, and development of watering

facilities.

Conservation practices on dry-farmed cropland include

terraces, sediment-control basins, summer fallow tillage, crop

residue management, and pest management.

Conservation practices on irrigated cropland and hayland

include irrigation system improvement, irrigation water

management, conservation tillage, crop rotation, crop residue

management, forage harvest management, and nutrient

management.

Conservation practices on irrigated pasture include

irrigation system improvement, irrigation water management,

pasture planting, development of watering facilities, fencing,

prescribed grazing, and nutrient management. 
128 Major Land Resource Areas

48A—Southern Rocky Mountains

This area (shown in fig. 48A-1) is in Colorado (76 percent),

New Mexico (11 percent), Utah (8 percent), and Wyoming (5

percent). It makes up about 45,920 square miles (119,000

square kilometers). The towns of Steamboat Springs, Glenwood

Springs, Aspen, Leadville, and Gunnison, Colorado, are in this

MLRA. Interstate 70 crosses the northern half of the area. This

MLRA has numerous national forests, including the Medicine

Bow National Forest in Wyoming; the Routt, Arapaho,

Roosevelt, Pike, San Isabel, White River, Gunnison, Grand

Mesa, Uncompahgre, Rio Grande, and San Juan National

Forests in Colorado; the Carson National Forest and part of the

Santa Fe National Forest in New Mexico; and parts of the

Manti-La Sal and Ashley National Forests in Utah. Rocky

Mountain National Park also is in this MLRA. The Pole

Mountain Military Reservation is in the Medicine Bow

National Forest. The Jemez, Picuris, Santa Clara, Uintah and

Ouray, and Taos Indian Reservations are in this MLRA. The

Black Canyon of the Gunnison National Monument and the

Curecanti National Recreation Area are directly west of

Gunnison, Colorado, in this area. Florissant Fossil Beds

National Monument is in this MLRA, west of Colorado Springs.

Physiography

Most of this area is in the Southern Rocky Mountains

Province of the Rocky Mountain System. The western

extension of the MLRA into Utah is in the Uinta Basin Section

of the Colorado Plateaus Province of the Intermontane Plateaus.

Small parts of the southwest corner and some isolated areas

farther west are in the Canyon Lands Section of the same

province and division. The Southern Rocky Mountains consist

primarily of two belts of strongly sloping to precipitous

mountain ranges trending north to south. Several basins, or

parks, are between the belts. Some high mesas and plateaus are

included. The ranges include the Sangre de Cristo Mountains,

the Laramie Mountains, and the Front Range in the east and the

San Juan Mountains and the Sawatch and Park Ranges in the

west. The ranges are dissected by many narrow stream valleys

having steep gradients. In some areas the upper mountain

slopes and broad crests are covered by snowfields and glaciers.

High plateaus and steep-walled canyons are fairly common,

especially in the west.

Elevation typically ranges from 6,500 to 14,400 feet (1,980

to 4,390 meters) in this area. The part of this MLRA in central

Colorado includes the highest point in the Rockies, Mount

Elbert, which reaches an elevation of 14,433 feet (4,400

meters). More than 50 peaks in the part of the MLRA in

Colorado are at an elevation of more than 14,000 feet (4,270

meters). Many small glacial lakes are in the high mountains.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Colorado Headwaters (1401), 17 percent; Gunnison (1402), 13

percent; White-Yampa (1405), 11 percent; South Platte (1019),

10 percent; Upper Arkansas (1102), 9 percent; Rio Grande

Headwaters (1301), 9 percent; Rio Grande-Elephant Butte

(1302), 7 percent; North Platte (1018), 6 percent; Lower Green

(1406), 5 percent; San Juan (1408), 5 percent; Upper ColoradoDolores (1403), 5 percent; and Upper Canadian (1108), 3

percent. The headwaters of many of the major rivers on the

High Plains and the Colorado Plateau are in this area. The

Continental (or Great) Divide also is in this area. The North and

South Platte, Arkansas, and Rio Grande Rivers drain toward the

Atlantic Ocean, and the Green, Yampa, and Colorado Rivers

drain toward the Pacific Ocean. The Rio Grande is a National

Wild and Scenic River in northern New Mexico, which is in the

southern part of this MLRA.

Geology

The mountains in this area were formed mainly by crustal

uplifts during the late Cretaceous and early Tertiary periods.

The Rockies on the east side of this area are called the “Front

Figure 48A-1: Location of MLRA 48A in Land Resource Region E.
of the United States 129

Range,” which is a fault block that has been tilted up on edge

and uplifted. It was tilted up on the east edge, so there is a steep

front on the east and the west side is more gently sloping. The

rocks exposed in the mountains are mostly Precambrian

igneous and metamorphic rocks, which in many places are

flanked by steeply dipping Mesozoic sedimentary rocks.

Younger igneous rocks, primarily basalt and andesitic lava

flows, tuffs, breccias, and conglomerates, are throughout this

area. Representative formations in this area are the Silver Plume

and Pikes Peak granites, San Juan Volcanics, and Mancos Shale.

Many of the highest mountain ranges were reshaped by

glaciation during the Pleistocene. Alluvial fans at the base of

the mountains are recharge zones for local basin and valley fill

aquifers. They also are important sources of sand and gravel.

Climate

The average annual precipitation ranges from 7 to 63 inches

(180 to 1,600 millimeters) but is dominantly 14 to 32 inches

(355 to 815 millimeters). Summer rainfall commonly occurs as

high-intensity, convective thunderstorms. About half of the

annual precipitation occurs as snow in winter; this proportion

increases with elevation. In the mountains, deep snowpacks

accumulate throughout the winter and generally persist into

spring or early summer, depending on elevation. Some

permanent snowfields and small glaciers are on the highest

mountain peaks. In the valleys at the lower elevations, snowfall

is lighter and snowpacks can be intermittent. The average

annual temperature is 26 to 54 degrees F (-3 to 12 degrees C).

The freeze-free period averages 135 days and ranges from 45 to

230 days, decreasing in length with elevation. The climate of

this area is strongly dependent upon elevation; precipitation is

greater and temperatures are cooler at the higher elevations.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 8.5%; ground water, 0.0%

Livestock—surface water, 2.7%; ground water, 0.4%

Irrigation—surface water, 77.7%; ground water, 5.6%

Other—surface water, 2.9%; ground water, 2.1%

The total withdrawals average 845 million gallons per day

(3,200 million liters per day). About 8 percent is from ground

water sources, and 92 percent is from surface water sources.

Water from the streams and lakes is abundant and generally of

excellent quality. In some places, mining activities in the late

1800s have contributed to the degraded quality of surface

water, mainly because of elevated levels of metals. The lower

valleys depend on streamflow from this area for irrigation water.

Most of the streamflow is from snowmelt, which typically

occurs from March to June, so reservoirs or a source of ground

water is needed to supply water for irrigation late in the

growing season. This MLRA provides most of the water for the

Denver metropolitan area, which lies just to the east.

This area has only two extensive aquifers. One is the

unconsolidated to consolidated silt, sand, and gravel of the

High Plains and equivalent aquifers in the southern part of

Carbon County, Wyoming. The other is the Leadville

Limestone aquifer in Colorado. The water from the High Plains

aquifer is of good quality, and high-yielding wells are common

in areas of this aquifer. The water is used for irrigation,

livestock, domestic supply, oil and gas exploration, and

mining. It is hard or moderately hard and has a median

concentration of about 300 parts per million (milligrams per

liter) total dissolved solids. The Leadville Limestone has salty

water at depth, but the level of total dissolved solids is

generally less than 500 parts per million (milligrams per liter).

Because of ample supplies of surface water and the lower

quality of this ground water, the Leadville Limestone aquifer

has not been extensively developed in this area.

Limited quantities of ground water occur in the basin and

valley fill sediments in most of the streams and rivers at the

lower elevations in this area. These aquifers are directly

connected with the streams, so water quality is similar to that in

the surface runoff. The water is generally of good quality and is

suitable for all uses.

Soils

The dominant soil orders in this MLRA are Mollisols,

Alfisols, Inceptisols, and Entisols. The soils in the area

dominantly have a frigid or cryic soil temperature regime and

an ustic or udic soil moisture regime. Mineralogy is typically

mixed, smectitic, or paramicaceous. In areas with granite,

gneiss, and schist bedrock, Glossocryalfs (Seitz, Granile, and

Leadville series) and Haplocryolls (Rogert series) formed in

colluvium on mountain slopes. Dystrocryepts (Leighcan and

Mummy series) formed on mountain slopes and summits at the

higher elevations. In areas of andesite and rhyolite bedrock,

Dystrocryepts (Endlich and Whitecross series) formed in

colluvium on mountain slopes. In areas of sedimentary

bedrock, Haplustolls (Towave series) formed on mountain

slopes at low elevations and with low precipitation.

Haplocryolls (Lamphier and Razorba series), Argicryolls

(Cochetopa series), and Haplocryalfs (Needleton series) formed

in colluvium on mountain slopes at high elevations.

Biological Resources

The potential vegetation in this area is grass and sagebrush

at the lower elevations, montane and subalpine coniferous

forest and some grassland at the mid and high elevations, and

alpine tundra on the mountain peaks above timberline (at an

elevation of about 11,500 feet, or 3,505 meters). Some common

plants are mountain big sagebrush, western wheatgrass, and

needleandthread at the lower elevations; ponderosa pine,
130 Major Land Resource Areas

Rocky Mountain Douglas-fir, white fir, Arizona fescue,

mountain muhly, common snowberry, Parry’s oatgrass, and

mountain brome at mid elevations; Engelmann spruce,

subalpine fir, corkbark fir, lodgepole pine, limber pine,

bristlecone pine, grouse whortleberry, elk sedge, and Thurber’s

fescue at the higher elevations; and kobresia, alpine bluegrass,

alpine clover, and golden avens above timberline.

Wildlife species in the alpine tundra include white-tailed

ptarmigan, rosy finch, pika, yellow-bellied marmot, long-tailed

weasel, bighorn sheep, and mountain goats. In the slightly

lower, montane to subalpine forested sites, typical species

include chickaree, Albert’s squirrel, golden-mantled ground

squirrel, beaver, black bear, elk, mule deer, moose, Steller’s jay,

golden eagle, blue grouse, black-billed magpie, mountain

chickadee, Clark’s nutcracker, and common raven. There is

considerable overlap of species between the montane and lower

shrub-grassland habitats; however, typical species in these

lower areas include bobcat, coyote, mountain lion, sage grouse,

western rattlesnake, bullsnake, Merriam’s turkey, golden eagle,

and piñon jay.

Habitats for fish are varied in this area and include streams

and rivers, small alpine lakes, and larger lakes and reservoirs.

The species of fish in streams and lakes at the higher elevations

are rainbow, brown, cutthroat, brook, and lake trout; kokanee;

and mountain whitefish. These species also occur at the lower

elevations, and some waters at the lower elevations also contain

northern pike, yellow perch, and a variety of nongame species.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 1%

Grassland—private, 16%; Federal, 22%

Forest—private, 11%; Federal, 41%

Urban development—private, 1%

Water—Federal, 1%

Other—private, 2%; Federal, 5%

Nearly 70 percent of this area is federally owned. The rest

consists of farms, ranches, or other private holdings. Nearly all

of the land in this MLRA is in natural vegetation. Grazing,

forestry, recreation, and watershed are the main uses. Small

areas of hayland and pasture, some of it irrigated, are in some

valleys. Local ranchers commonly graze livestock in national

forests during the summer and then move the livestock to lower

elevations in the winter. The large areas of public land provide

excellent opportunities for outdoor recreation, particularly

hunting, fishing, skiing, camping, hiking, boating, and

sightseeing. The spectacular mountain scenery in many parts of

this MLRA contributes to the popularity of these activities and

attracts tourists from distant regions. Recreation supports a

significant tourism industry upon which many local economies

are dependent.

The major soil resource concerns are erosion by wind and

Figure 48B-1: Location of MLRA 48B in Land Resource Region E.

48B—Southern Rocky Mountain Parks

This area (shown in fig. 48B-1) is in Colorado (96 percent)

and Wyoming (4 percent). It makes up about 2,325 square miles

(6,020 square kilometers). The town of Walden, in the northern

part of this MLRA, is in a wide valley locally known as North

Park. The town of Kremmling is in a valley locally known as

Middle Park. The town of Hartsel, in the center of the southern

part of the MLRA, is in a broad intermontane basin locally

known as South Park. Interstate 70 passes between the northern

water and maintenance of the productivity of the soils.

Minimizing the sediment that reaches watercourses also is a

concern. Proper grazing use is a concern in areas of grazing

land. In timbered areas, the primary concerns during timber

harvesting are controlling erosion on roads and skid trails

and minimizing soil compaction caused by harvesting

equipment. 
of the United States 131

and southern parts of the MLRA. The northern part is bordered

by the Medicine Bow, Routt, and Arapaho National Forests, and

the southern part is bordered by the San Isabel and Pike

National Forests. The Arapaho National Wildlife Refuge is

directly south of the town of Walden.

Physiography

This area is within the Southern Rocky Mountains Province

of the Rocky Mountain System. It consists of nearly level to

rolling mountain parks and valleys and a few narrow mountain

ridges. It occurs as two separate parts in the center of the

Southern Rockies. The southern half of the northern part is on

the west side of the Continental Divide, and the rest of the

MLRA is on the east side of the divide. Elevation ranges from

7,850 to 10,850 feet (2,395 to 3,310 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

North Platte (1018), 41 percent; South Platte (1019), 35

percent; Colorado Headwaters (1401), 23 percent; and Upper

Arkansas (1102), 1 percent. The North Platte River leaves

Colorado and enters Wyoming in the northern half of the

northern part of the MLRA (North Park). The Colorado River is

in the southern half of the northern part of the MLRA (Middle

Park). The South Platte River is in the southern part of the

MLRA (South Park).

Geology

The mountain valleys and parks that are characteristic of this

MLRA are surrounded by high mountain peaks of the adjacent

Southern Rocky Mountains MLRA. Steep slopes give rise to

steep-gradient streams that are able to move cobbles and gravel

from the mountain slopes down into the valleys. The coarse

textured sediments on the surface of this area were deposited by

either glacial meltwater or present-day rivers. Buried deep

beneath the sediments is a complex of sedimentary and igneous

rocks. Residuum from sedimentary rocks is on the steeper

slopes that were not covered by alluvium and glacial outwash.

Climate

The average annual precipitation is mainly 10 to 16 inches

(255 to 405 millimeters), but it is as high as 28 inches (710

millimeters) at the higher elevations that border the Southern

Rocky Mountains MLRA. Precipitation generally increases

with elevation. Rainfall occurs as high-intensity, convective

thunderstorms during the growing season. About half of the

annual precipitation falls as snow. Soil moisture is unevenly

distributed within short distances because of snowdrifts. The

amount of precipitation is highly influenced by rain shadows.

The surrounding peaks receive most of the precipitation as

storm systems traverse the area. The average annual temperature

is 35 to 42 degrees F (1 to 6 degrees C). The freeze-free period

averages 95 days and ranges from 70 to 120 days, decreasing in

length with elevation.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 0.2%; ground water, 0.0%

Irrigation—surface water, 91.1%; ground water, 8.3%

Other—surface water, 0.3%; ground water, 0.1%

The total withdrawals average 300 million gallons per day

(1,135 million liters per day). About 8 percent is from ground

water sources, and 92 percent is from surface water sources.

Perennial streams originating from snowmelt in the adjacent

high mountains furnish an abundance of water for irrigation of

hay meadows in June and July. In August, the streams are often

short of water. Large reservoirs in the area store water for

domestic use, power supply, and irrigation outside the area. The

surface water from the mountain runoff is of good quality and is

generally suitable for all uses.

Some ground water is available locally in valley fill deposits

under the larger streams and rivers in this area. The ground

water and surface water in the valleys are connected, and the

quality of the ground water is almost the same as that of the

surface water.

Soils

The dominant soil order in this MLRA is Mollisols. Alfisols

are of lesser extent. The soils are very shallow to deep,

generally well drained, and loamy or clayey and have mixed or

smectitic mineralogy. The soil temperature regime is

dominantly cryic, but it is frigid in some small areas, primarily

on south- or west-facing slopes. The soil moisture regime is

mainly ustic, but a marginal aridic regime has been identified

in areas where the average annual precipitation is less than

about 12 inches (305 millimeters). The most extensive great

group is Argicryolls (Hodden, Lucky, Parlin, Tiagos, and Cabin

series), which commonly formed in outwash and slope alluvium

on outwash terraces, fan remnants, hills, and mountain slopes.

Haplocryolls (Redcloud and Tealson series) formed in outwash

and slope alluvium on outwash terraces, valley side slopes,

hills, and ridges. Haplocryalfs (Gebson and Harsha series)

formed in slope alluvium and outwash on outwash terraces, fan

remnants, hills, ridges, and mountain slopes. Cryaquolls

(Dobrow and Randman series) formed in alluvium on stream

terraces and flood plains.

Biological Resources

This area supports grass and grass-shrub vegetation.

Mountain big sagebrush, Idaho fescue, bluebunch wheatgrass,
132 Major Land Resource Areas

49—Southern Rocky Mountain Foothills

This area (shown in fig. 49-1) is in Colorado (58 percent),

Wyoming (27 percent), and New Mexico (15 percent). It makes

up about 11,130 square miles (28,845 square kilometers). The

major cities in or adjacent to this MLRA are Laramie,

Wyoming; Fort Collins, Boulder, Denver, Colorado Springs, and

Pueblo, Colorado; and Santa Fe and Las Vegas, New Mexico.

Interstates 25, 70, and 80 cross the MLRA. Part of the Medicine

Bow National Forest is in the northern tip of this area, in

Wyoming; parts of the Roosevelt, Pike, and San Isabel National

Forests are in this area in Colorado; and part of the Santa Fe

National Forest is in the southern end of this area, in New

Mexico. The Rocky Flats Nuclear Arsenal, Peterson Air Force

Base, most of the Air Force Academy grounds, and part of the

Fort Carson Military Reservation are in the part of this area in

Colorado.

streambank wheatgrass, and muttongrass are the common plants

in North Park and Middle Park. Western wheatgrass, Arizona

fescue, mountain muhly, needleandthread, and Parry’s oatgrass

are common in South Park.

Some of the major wildlife species in this area are black bear,

elk, mule deer, antelope, coyote, beaver, snowshoe hare,

jackrabbit, and sage grouse. Moose were introduced in North

Park and flourished as their range expanded to the south.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 6%

Grassland—private, 59%; Federal, 26%

Forest—private, 3%; Federal, 1%

Urban development—private, 3%

Water—private, 1%

Other—private, 1%

About one-fourth of this area is Federal land leased to

ranchers for grazing by cattle and sheep. The rest consists

mainly of privately owned ranches. Irrigated pastures and

hayland adjacent to rivers and streams produce most of the

forage in the area. The hay consists mainly of grasses and

sedges and a small amount of clover. Grazing land is

sparsely vegetated with grasses and shrubs and produces a low

amount of forage because of inadequate rainfall and low

temperatures.

The major soil resource concerns are water erosion, a short

growing season, steep slopes, and shallow and rocky soils.

Conservation practices on hayland and pasture generally

include management of crop residue, nutrients, pesticides, and

irrigation water. Forage harvest management is important on the

rangeland and pasture in the area. 

Figure 49-1: Location of MLRA 49 in Land Resource Region E.

Physiography

Almost half of this area is in the Southern Rocky Mountains

and Wyoming Basin Provinces in the Rocky Mountain System.

The rest is in the Colorado Pediment, Raton, and High Plains

Sections of the Great Plains Province of the Interior Plains. The

northern part of the MLRA consists of the Laramie Mountains.

The central and southern parts generally are bounded on the

east by the Great Plains and on the west by the Southern Rocky

Mountains. Elevation ranges from 5,000 feet (1,525 meters) to

8,000 feet (2,440 meters) in most of the MLRA, but small

mountains in the area are as high as 10,000 feet (3,050 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Upper Arkansas (1102), 36 percent; South Platte (1019), 27

percent; North Platte (1018), 22 percent; Upper Canadian

(1108), 11 percent; Upper Pecos (1306), 3 percent; and Upper

Cimarron (1104), 1 percent. The Laramie and North Platte

Rivers and their associated tributaries are the principal streams

in the Wyoming portion of the MLRA. The Cache La Poudre,
of the United States 133

Big Thompson, Saint Vrain, South Platte, Arkansas, Saint

Charles, Huerfano, Cucharas, and Purgatoire Rivers, Clear

Creek, Fountain Creek, and their associated tributaries are the

principal streams in the Colorado portion. The Vermejo,

Cimarron, Pecos, and Mora Rivers and their associated

tributaries are the principal streams in the New Mexico

portion.

Geology

This area has been impacted by the geologic processes of

uplift, folding, and faulting and by subsequent erosion and

deposition. The Southern Rocky Mountains were uplifted 50 to

70 million years ago during the Laramide uplift. Most of this

MLRA is adjacent to this uplift and was also affected. The

uplift induced erosion of the relatively soft Late Pennsylvanian

to Cretaceous sedimentary rocks from the uplands and

dissected the underlying crystalline Precambrian rocks. The

relief of the area was reduced by a combination of erosion of

uplands and alluvial filling. Approximately 7 million years

ago, a large portion of the area was uplifted again to elevations

of 14,000 feet (4,270 meters) or more at the core of the

Laramide uplift. Since then, precipitation occurring as both rain

and snow led to the renewal of erosion and subsequent alluvial

fills. The Wyoming portion of the MLRA, the Laramie

Mountains, consists primarily of Precambrian plutonic rocks

with Pennsylvanian and Permian sedimentary rocks folded and

faulted at the margin of the range. The Colorado and New

Mexico portions of the area consist primarily of remnants of the

uplifted and folded Pennsylvanian through Cretaceous

sedimentary rocks forming hogbacks, ridges, and hills, the

ranges of which trend in a general north-south direction,

parallel to the uplifted Southern Rocky Mountains. Tertiary

volcanic flows filled valleys in some areas. After extensive

erosion, these more resistant volcanic rocks now form

prominent mesas, such as North and South Table Mountains

near Golden, Colorado, and Fishers Peak Mesa near the

Colorado-New Mexico border. Stream erosion from the eastern

front of the Southern Rocky Mountains fostered the creation of

a sequence of large alluvial fan remnants, pediments, and

terrace deposits in this MLRA.

Climate

The average annual precipitation is 12 to 25 inches (305 to

635 millimeters) in most of this area, but it ranges from 10 to 35

inches (255 to 890 millimeters), generally increasing with

elevation. The highest precipitation occurs in the Laramie

Mountains, in Wyoming, and the lowest precipitation occurs in

the Arkansas River Valley, above Salida, Colorado. Most of the

rainfall occurs as high-intensity, convective thunderstorms

during the growing season. Winter precipitation occurs as snow.

The average annual temperature is 36 to 54 degrees F (2 to 12

degrees C). The freeze-free period averages 140 days and ranges

from 90 to 195 days, decreasing in length with elevation and

from south to north.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 59.1%; ground water, 7.3%

Livestock—surface water, 0.7%; ground water, 0.2%

Irrigation—surface water, 22.6%; ground water, 4.5%

Other—surface water, 4.5%; ground water, 1.0%

The total withdrawals average 330 million gallons per day

(1,250 million liters per day). About 13 percent is from ground

water sources, and 87 percent is from surface water sources. The

numerous major streams crossing this area provide some public

supply water and irrigation water for narrow belts of cropland in

the stream valleys. The only limitation affecting the quality of

the surface water in this area is a high sediment load. Both

surface water and ground water are scarce in the part of this area

in New Mexico.

Alluvium in the South Platte River and its tributaries

provides some water for irrigation, livestock, and domestic use

in the northern part of this area. Water from this aquifer is hard.

It is a calcium-sulfate type of water, and its level of total

dissolved solids typically exceeds 1,000 parts per million

(milligrams per liter). Alluvium in the valleys of Fountain

Creek and Black Squirrel Creek, in the middle of this area,

provides some ground water for agricultural and domestic uses.

This water is moderately hard to very hard but typically

contains less than 550 parts per million (milligrams per liter)

total dissolved solids. Another source of ground water is the

Denver Basin Aquifer System southeast of Denver. Consolidated

sandstone and conglomerate beds in this aquifer provide water

that is slightly less hard than the water from the river alluvium,

and it generally contains less than 1,000 parts per million

(milligrams per liter) total dissolved solids.

Soils

The dominant soil orders in this MLRA are Mollisols,

Alfisols, Inceptisols, and Entisols. The soils in the Colorado

and New Mexico portions of the MLRA dominantly have a

frigid or mesic soil temperature regime. Those in the Wyoming

portion have a frigid or cryic soil temperature regime. A few of

the higher peaks and some north aspects have a cryic soil

temperature regime. Most of the soils in the area have an ustic

soil moisture regime, but those on the higher peaks and on

some north aspects have a udic soil moisture regime. The soils

in the area dominantly have smectitic or mixed mineralogy.

They are very shallow to very deep and are dominantly well

drained. The texture is dominantly loamy in soils that formed

in material weathered from igneous and metamorphic rocks and

is dominantly loamy or clayey in soils that formed in material
134 Major Land Resource Areas

51—High Intermountain Valleys

This area (shown in fig. 51-1) is in Colorado (89 percent)

and New Mexico (11 percent). It makes up about 4,030 square

miles (10,445 square kilometers). The part of this area in

Colorado is known locally as the San Luis Valley. The area has

weathered from sedimentary rocks. Some of the most extensive

and representative great groups are Haplustolls (Baller series),

Argiustolls (Nederland, Nunn, Santa Fe, and Enmedio series),

Haplustalfs (Fort Collins, Stoneham, and Dargol series),

Haplustepts (Stout series), Ustorthents (Lorencito and Saruche

series), and Paleustolls (Flatirons series).

Biological Resources

This area supports grassland, shrub-grassland, and forestland

vegetation. Grassland that supports blue grama, buffalograss,

and wheatgrasses is common at the lower elevations. Pinyon

pine, juniper, true mountain mahogany, blue grama,

needleandthread, and wheatgrasses are common in the southern

Colorado and New Mexico portions of the MLRA. Ponderosa

pine, Gambel oak, Douglas-fir, white fir, kinnikinnick, Parry’s

oatgrass, and Arizona fescue are common at the higher

elevations and in the Wyoming portion of the MLRA.

Cottonwood grows along the major streams.

Some of the major wildlife species in this area are elk, mule

deer, antelope, jackrabbit, cottontail, and mourning dove.

Waterfowl inhabit areas near perennial streams, lakes, and

reservoirs.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 4%

Grassland—private, 48%; Federal, 11%

Forest—private, 25%; Federal, 5%

Urban development—private, 6%

Other—private, 2%

About 75 percent of this area consists of privately owned

farms, ranches, and forestland. The rest is mostly Federal land.

About 30 percent of the area is forestland. Less than 5 percent is

irrigated cropland. The major crops are small grains and hay.

The native rangeland is grazed in spring and summer. Firewood

and fenceposts are produced on the forestland.

The major soil resource concerns are water erosion, steep

slopes, shallow and rocky soils, and a high shrink-swell

potential. Conservation practices on cropland generally

include management of crop residue, nutrients, pesticides, and

irrigation water. Forage harvest management is important on the

rangeland and pasture in the area. 

Figure 51-1: Location of MLRA 51 in Land Resource Region E.

no major cities or interstate highways. U.S. Highway 160 is the

major east-west road, and U.S. Highway 285 is the major northsouth road. The town of Alamosa, Colorado, is in this area, and

Taos, New Mexico, is directly south of the area. Parts of the

Great Sand Dunes National Park are in and adjacent to this

MLRA, and the Monte Vista and Alamosa National Wildlife

Refuges are in the MLRA.

Physiography

This MLRA is in the Southern Rocky Mountains Province

of the Rocky Mountain System. It is an isolated, high mountain

valley bounded by the Sangre de Cristo Mountains on the east

and the La Garita and San Juan Mountains on the north and

west. Much of the MLRA consists of nearly level to gently

sloping areas of old valley fill. Most of the southern end

consists of gently sloping to steep hills underlain by volcanic

rocks. Elevation ranges from 6,900 to 8,860 feet (2,105 to

2,700 meters). Local relief generally is slight, but it is as much

as 330 feet (100 meters) in the southern tip of the area.
of the United States 135

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows: Rio

Grande Headwaters (1301), 88 percent, and Rio GrandeElephant Butte (1302), 12 percent. The headwaters of the Rio

Grande are in the mountains west of this area. The Alamosa,

Trinchera, Culebra, and Chama Rivers join the Rio Grande in

this MLRA.

Geology

Most of this area is covered with old alluvial deposits

washed into the valley from the adjacent mountains. Because of

a low amount of precipitation, these old deposits commonly

have not been reworked. The only river that has a well-defined

flood plain and some terraces is the Rio Grande. The southern

end of the area has basalt flows with some associated volcanic

cones at the surface. Also, it has some scattered outcrops of tuff

and rhyolite.

Climate

The average annual precipitation is mainly 7 to 10 inches

(180 to 255 millimeters), but it ranges to 21 inches (535

millimeters) in areas that border the mountains. It increases with

elevation from the town of Center, where the lowest

precipitation in the area occurs. Most of the rainfall occurs as

high-intensity, convective thunderstorms during the growing

season. Winter precipitation occurs as snow. The average

annual temperature ranges from 38 to 46 degrees F (4 to 8

degrees C). The freeze-free period averages 130 days and

ranges from 110 to 155 days, decreasing in length with

elevation.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 0.0%; ground water, 0.0%

Irrigation—surface water, 82.5%; ground water, 17.4%

Other—surface water, 0.1%; ground water, 0.1%

The total withdrawals average 2,305 million gallons per day

(8,725 million liters per day). About 18 percent is from ground

water sources, and 82 percent is from surface water sources.

Because of low precipitation, most of the MLRA supports only

a sparse cover of rangeland plants, but rainfall at the higher

elevations is adequate for a good cover of grass and shrubs. The

Alamosa and Rio Grande Rivers and small reservoirs on

intermittent streams flowing into the area from the surrounding

mountains provide drinking water. The Chama River is an

important source of water in the southern part of the area. The

content of dissolved salts is low where the surface water comes

out of the mountains, but it increases quickly downstream as

salt-laden runoff and irrigation tailwater from the valley floor

flow into the rivers. The surface water is generally of good

enough quality for irrigation and drinking. Acid mine drainage

has decreased the pH of some streams draining mined lands in

the western part of this MLRA.

Wells that tap ground water in the deep valley fill are

important sources of water for irrigation and domestic use. The

valley fill aquifer in Colorado is known locally as the San Luis

Valley aquifer system. The upper 130 feet of this aquifer

contains unconfined ground water, but where clay, fine sand, or

volcanic rock layers occur in the alluvium, ground water

beneath those layers is confined. The quality of the confined

ground water is better than that of the unconfined water. The

median value of total dissolved solids is 184 parts per million

(milligrams per liter) in the confined aquifer and exceeds 310

parts per million in the shallow, unconfined aquifer. The valley

fill aquifer in New Mexico is called the Rio Grande Valley,

north, aquifer. The total dissolved solids in this water average

about 230 parts per million (milligrams per liter). Water in both

aquifers can be soft or hard. Salinity is a problem in much of the

area. Ground water contains much lower levels of total

dissolved salts near the recharge areas close to the mountains

than in down-gradient areas lower in the valley. Salts are

dissolved from soils during periods of natural runoff and

irrigation return flows.

Soils

The dominant soil orders in this MLRA are Aridisols and

Entisols. The soils in the area dominantly have a frigid soil

temperature regime, an aridic soil moisture regime, and mixed

mineralogy. They generally are deep or very deep and

somewhat excessively drained to somewhat poorly drained.

The texture varies. Haplocalcids formed in alluvium on alluvial

fans, fan remnants, and valley sides (Garita and Luhon series)

and on valley dunes and ridges (Space City series). Haplargids

(Graypoint and San Arcacio series) formed in alluvium on

alluvial fans, fan remnants, and stream terraces. Haplocambids

(Travelers series) formed in residuum on basalt flows and mesas.

Natrargids (Hooper, Mosca, and San Luis series) and

Psammaquents (Gunbarrel series) formed in alluvium on flood

plains, alluvial fans, and stream terraces.

Biological Resources

This area supports desert shrub-grassland vegetation. The

common plants are greasewood, rabbitbrush, fourwing saltbush,

saltgrass, alkali sacaton, western wheatgrass, sedges, and rushes

at the lower elevations and twoneedle pinyon, oneseed juniper,

Indian ricegrass, blue grama, needleandthread, western

wheatgrass, and muttongrass at the higher elevations. Big

sagebrush is common on the east side of the MLRA. Narrowleaf

cottonwood is along the major streams.

Some of the major wildlife species in this area are elk, mule
deer, antelope, jackrabbit, cottontail, pheasant, mourning dove,

and waterfowl.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 16%

Grassland—private, 58%; Federal, 18%

Forest—private, 1%

Urban development—private, 2%; Federal, 1%

Water—private, 1%; Federal, 1%

Other—private, 2%

About 75 percent of this area consists of privately owned

farms and ranches. The rest is mostly Federal land. Desert

shrubs and short grasses cover most of the area. About 16

percent of the area is irrigated cropland. The major crops are

potatoes, malt barley and other small grains, field peas, coolseason vegetables, and hay. The native rangeland is grazed in

summer, but it has a low carrying capacity.

The major soil resource concerns are water erosion, wind

erosion, and saline and sodic soils. Also, a high water table is a

concern in some areas. Conservation practices on cropland

generally include management of crop residue, nutrients,

pesticides, and irrigation water. Forage harvest management is

important on the hayland and pasture in this area. 
137

Figure F-1: Location of Land Resource Region F.

F—Northern Great Plains Spring Wheat

Region

This region (shown in fig. F-1) is in North Dakota (48

percent), Montana (23 percent), South Dakota (23 percent), and

Minnesota (6 percent). It makes up 142,225 square miles

(368,535 square kilometers).

Much of this region has been topographically smoothed by

continental glaciation and is blanketed by undulating till and

level to gently rolling lacustrine deposits. The Red River

Valley, in the eastern part of the region, is dominated by

lacustrine deposits, as are other areas where ancient glacial

lakes occurred. The surficial geology in the southwestern part

of the region consists mainly of residual sediments weathered

from sedimentary rocks. Alluvial deposits are along

drainageways.

Fertile soils and dominantly smooth topography in this

region favor agricultural uses (fig. F-2), but relatively low

precipitation and a short growing season severely limit the

choice of crops that can be grown. The climate is dry and

continental, characterized by short, hot summers and long, cold

winters. High winds are an important climatic factor. The region

also is subject to periodic intense droughts. The mean annual

precipitation in most of the region is 14 to 21 inches (355 to

535 millimeters). About 30 percent of the annual precipitation

occurs as snow during the winter, and the rest occurs during the

growing season. In most of the region, the mean annual air

temperature is 39 to 45 degrees F (4 to 7 degrees C) and the

freeze-free period ranges from 130 to 170 days. The mean

annual air temperature and length of the freeze-free period

increase from north to south.

The total withdrawals of freshwater in this region average

3,005 million gallons per day (11,375 million liters per day).

About 92 percent is from surface water sources, and 8 percent is

from ground water sources. About 80 percent of the water is

used for cooling thermoelectric power plants.

The soils in this region are dominantly Mollisols. Ustolls

and Aquolls are the dominant suborders. Ustolls are on uplands,

and Aquolls are in low wet areas and along streams. Aquolls are

extensive in the Red River Valley. Some of the Ustolls have a

high content of sodium, and some of the Aquolls have a high
138 Major Land Resource Areas

Figure F-2: Cropland, pasture, and rangeland in an area of Land Resource Region F.

content of sodium and lime. Other important soils are Orthents

on the steeper slopes. The soils in the region dominantly have a

frigid soil temperature regime, an ustic or aquic soil moisture

regime, and mixed or smectitic mineralogy.

About 96 percent of the land in this region is privately

owned. The native vegetation consists mainly of mixed and tall

prairie grasses. The main crop is spring wheat, which is grown

by dryfarming methods. Other spring-planted grains, flax, and

hay also are grown. Potatoes, sugar beets, soybeans, and corn

are important crops in the Red River Valley. The main

management concerns in areas of cropland are a reduced

nutrient content, increasing salinity, and susceptibility to water

erosion and wind erosion. 
of the United States 139

Figure 52-1: Location of MLRA 52 in Land Resource Region F.

52—Brown Glaciated Plain

This area is entirely in Montana (fig. 52-1). It makes up

about 23,040 square miles (59,700 square kilometers). It

includes the cities of Great Falls and Havre. Interstate 15

crosses the west end of the MLRA. Ft. Peck Dam, the first dam

on the Missouri River, is in the southeast corner of this MLRA.

The Malmstrom Air Force Base and Blackfeet, Rocky Boy’s,

Fort Belknap, and Fort Peck Indian Reservations are in this

MLRA. This area has numerous national wildlife refuges,

including Lake Thibadeau, Benton Lake, and Bowdoin National

Wildlife Refuges.

Physiography

Almost the entire MLRA is in the Missouri Plateau,

Glaciated, Section of the Great Plains Province of the Interior

Plains. Part of the southwest corner of the area is in the Missouri

Plateau, Unglaciated, Section. Elevation generally ranges from

1,970 to 4,600 feet (600 to 1,400 meters), increasing from east

to west. The glaciated plain in this area generally is nearly level

to gently rolling, but belts of steep slopes border some of the

larger rivers. The Milk River has extensive flood plains, but the

flood plains along other streams are narrow and discontinuous.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Milk (1005), 59 percent; Missouri-Marias (1003), 31 percent;

Missouri-Musselshell (1004), 6 percent; and Missouri-Poplar

(1006), 4 percent. The Teton, Marias, and Milk Rivers occur in

this area. A short reach of the Missouri River that flows through

the southwest corner of the area is part of the Missouri Breaks

National Wild and Scenic River.

Geology

Almost all of this MLRA is covered by glacial till plains.

Some glacial lacustrine deposits occur, and shale may be

exposed on some uplands in the west. Alluvial deposits are

extensive along the Milk River but occur in narrow and

discontinuous strips along other streams and rivers. Low

terraces occur along the major rivers, and some alluvial fans

occur at the western boundary of the area and around the

Sweetgrass Hills, just outside the northern boundary.

Climate

The average annual precipitation is 10 to 17 inches (255 to

430 millimeters) in most of this area. Some of the higher

elevations in the far west part of the area receive 21 inches (535

millimeters) of annual precipitation. About 70 percent of the

rainfall occurs as high-intensity, convective thunderstorms

during the growing season. The maximum precipitation occurs

from spring through early summer. Precipitation in winter

occurs as snow. This area typically receives 25 to 50 inches

(635 to 1,270 millimeters) of snow each year. The average

annual temperature is 38 to 45 degrees F (4 to 7 degrees C). The

freeze-free period averages 140 days and ranges from 120 to

165 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 1.9%; ground water, 0.0%

Livestock—surface water, 0.3%; ground water, 0.3%

Irrigation—surface water, 94.7%; ground water, 1.1%

Other—surface water, 0.6%; ground water, 1.0%

The total withdrawals average 1,085 million gallons per day

(4,105 million liters per day). About 2 percent is from ground

water sources, and 98 percent is from surface water sources.

Most of the area depends on precipitation for water for both

range and crops. The Milk and Teton Rivers provide irrigation

water to their flood plains and to areas adjacent to the flood

plains. In the uplands, water for livestock is stored in small

reservoirs. The surface water generally is suitable for most uses,

except during periods of low flow. The seasonal variation in

quantity of surface water generally poses more of a problem for

use than water quality.

Some ground water is pumped from the alluvial fill in the

lower half of the Milk River. Alluvial deposits and terrace

gravel deposits are the primary sources of ground water in

eastern Montana. The ground water is very hard and exceeds

national drinking water standards for dissolved solids and

sulfate. It is still used for drinking water, livestock, and

irrigation. The glacial drift yields a moderate amount of

ground water that is hard but otherwise of good quality. This

MLRA is underlain by Mesozoic sedimentary rock aquifers

consisting of sandstone, siltstone, shale, and limestone. Eagle

Sandstone under the western half provides soft water, and the

Judith River Formation under the eastern half provides hard

water. The content of dissolved solids in both aquifers
140 Major Land Resource Areas

exceeds national drinking water standards. Water from the

glacial drift is a calcium bicarbonate type, and water from the

Milk River alluvium and the Mesozoic sediments is a sodium

sulfate type.

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, and Mollisols. The soils in the area dominantly have a

frigid soil temperature regime, an ustic soil moisture regime,

and mixed or smectitic mineralogy. They generally are very

deep, well drained, and loamy or clayey. Natrustalfs (Elloam

and Thoeny series) and Haplustalfs (Phillips series) formed in

till on till plains. Ustorthents (Hillon and Sunburst series)

formed in till on till plains and hills. Argiustolls formed in till

on till plains and hills (Bearpaw, Joplin, Scobey, Telstad, and

Vida series) and in alluvium on alluvial fans, stream terraces,

and hills (Ethridge and Evanston series).

Biological Resources

This area supports grassland vegetation. Bluebunch

wheatgrass, needleandthread, western wheatgrass, green

needlegrass, and basin wildrye are the dominant species.

Some of the major wildlife species in this area are elk, mule

deer, white-tailed deer, antelope, coyote, badger, beaver,

raccoon, mink, jackrabbit, cottontail rabbit, ground squirrel,

pheasant, Hungarian partridge, sharp-tailed grouse, sage grouse,

ducks, geese, and swans. The species of fish in the area include

trout, walleye, northern pike, sauger, and perch.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 45%

Grassland—private, 36%; Federal, 16%

Urban development—private, 1%

Water—private, 1%

Other—private, 1%

Nearly all this area is in farms and ranches. Level tracts,

mostly in the western part of the area, are used as cropland,

which makes up almost one-half of the total area. Spring wheat

is the major cash crop, but feed grains and hay also are grown

on most farms. Most of the land in the eastern part of the area is

rangeland, but gently sloping soils are used for dry-farmed

wheat. Narrow, discontinuous strips along the Milk River are

irrigated. Feed grains, corn silage, hay, and tame pasture are

grown on much of the irrigated land, and sugar beets are an

important cash crop.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and

productivity of the soils, management of soil moisture, and

control of saline seeps. Inefficient water use on irrigated

cropland is a water resource concern. Plant resource concerns

are deterioration of plant condition, productivity, health, and

vigor; noxious and invasive plants; and wildfires. Animal

resource concerns are inadequate food, cover, and shelter.

Conservation practices on cropland generally include crop

residue management, minimum tillage, cover crops,

stripcropping, nutrient management, soil salinity management,

and pest management. Conservation practices that improve

water use and distribution on irrigated cropland generally

include irrigation water management, irrigation water delivery

systems, and on-farm irrigation practices, such as land leveling,

land smoothing, water-control structures, and sprinklers.

Noxious and invasive plants can be controlled by pest

management and prescribed grazing. Firebreaks reduce the

hazard of wildfires.

Conservation practices on rangeland generally include

prescribed grazing, fencing, and water developments.

Establishment of early and late season pastures supplements

forage production and helps to keep livestock off the rangeland

during critical growth periods. Range improvement practices

and the establishment of food plots benefit wildlife. 

53A—Northern Dark Brown Glaciated

Plains

This area (shown in fig. 53A-1) is in Montana (89 percent)

and North Dakota (11 percent). It makes up about 9,220 square

miles (23,885 square kilometers). The towns of Wolf Point and

Sidney, Montana, and Williston, North Dakota, are in this

MLRA. U.S. Highways 2 and 85 intersect directly west of

Williston. Most of the Fort Peck Indian Reservation is in this

MLRA. Medicine Lake and Lake Zahl National Wildlife

Refuges also are in this MLRA. Fort Union National Historic

Site and Fort Buford State Historical Site are on the southern

edge of the area.

Figure 53A-1: Location of MLRA 53A in Land Resource Region F.
of the United States 141

water for irrigation. Thus, only a small acreage is irrigated. The

Missouri River water is of good quality and is suitable for most

uses with minimal treatment.

There is a limited supply of ground water in the glacial till

deposits and the underlying Cenozoic Fort Union Formation.

This formation consists of soft, calcareous shales, siltstones,

and sandstones. Water from these aquifers is very hard and high

in total dissolved solids. The water from the Fort Union

Formation is a sodium sulfate type.

Soils

The dominant soil orders in this MLRA are Inceptisols and

Mollisols. The soils in the area dominantly have a frigid soil

temperature regime, an ustic soil moisture regime, and mixed or

smectitic mineralogy. They generally are very deep, moderately

well drained or well drained, and clayey or loamy. Calciustepts

(Zahill series), Natrustolls (Niobell series), and Calciustolls

(Zahl series) formed in till on till plains and moraines.

Haplustolls (Tally series) formed in eolian deposits, alluvium,

or glaciofluvial deposits on fans, terraces, and outwash plains

and in drainageways. Argiustolls formed in till (Vida and

Williams series) and mixed till and alluvium (Bowbells series)

on till plains, moraines, and hills. Argiustolls also formed in

alluvium or eolian deposits over till (Dooley series), alluvium

(Turner series), and alluvium, lacustrine deposits, or

glaciofluvial deposits (Farnuf series) on lake plains, fans, and

terraces and in drainageways.

Biological Resources

This area supports natural prairie vegetation characterized by

western wheatgrass, needleandthread, green needlegrass, and

blue grama. Little bluestem is an important species on the more

sloping and shallower soils. Prairie cordgrass, northern

reedgrass, and slim sedge are important species on wet soils.

Western snowberry, stiff goldenrod, echinacea, and prairie rose

are commonly interspersed throughout the area.

The major wildlife species in this area are mule deer, whitetailed deer, antelope, pheasant, sharp-tailed grouse, Hungarian

partridge, Canadian goose, mallard, blue-winged teal, pintail,

pelican, and shorebirds.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 56%

Grassland—private, 39%; Federal, 1%

Urban development—private, 1%

Water—private, 1%

Other—private, 2%

Most of this area is in farms and ranches. Slightly more than

one-half of the area is dry-farmed cropland. Spring wheat is the

Physiography

This MLRA is in the Missouri Plateau, Glaciated, Section of

the Great Plains Province of the Interior Plains. Elevation

ranges from 1,950 to 2,950 feet (595 to 900 meters), increasing

gradually from southeast to northwest. The gently undulating

to rolling till plains in this area are interrupted by more strongly

rolling and steep slopes adjacent to kettle holes, kames,

moraines, and major stream valleys.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Missouri-Poplar (1006), 84 percent; Missouri-Little Missouri

(1011), 7 percent; Lower Yellowstone (1010), 6 percent; and

Milk (1005), 3 percent. The Missouri River bisects the southern

part of this MLRA, and the Yellowstone River joins the

Missouri River just inside the North Dakota border. The Poplar

and Big and Little Muddy Rivers, all tributaries of the Missouri

River, occur in this area.

Geology

This area is covered by glacial till plains. Glacial features,

such as kettle holes, kames, and moraines, are common

throughout the plains. Some alluvial deposits are along the

Missouri River and its major tributaries. Unconsolidated sand and

gravel deposits are on high and low terraces along the Missouri

River and on low terraces along the other rivers in the area.

Climate

The average annual precipitation in this area is 12 to 15

inches (305 to 380 millimeters). About 70 percent of the rainfall

occurs as high-intensity, convective thunderstorms during the

growing season. Winter precipitation typically is snow. The

annual snowfall is 25 to 50 inches (635 to 1,270 millimeters).

The average annual temperature is 38 to 44 degrees F (3 to 7

degrees C). The freeze-free period averages 135 days and ranges

from 120 to 155 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 0.5%; ground water, 2.6%

Irrigation—surface water, 77.6%; ground water, 5.7%

Other—surface water, 5.9%; ground water, 7.6%

The total withdrawals average 105 million gallons per day

(395 million liters per day). About 16 percent is from ground

water sources, and 84 percent is from surface water sources. In

most years moisture is inadequate for maximum crop

production. In some areas dug ponds provide water for

livestock. The Missouri River is the only dependable source of
142 Major Land Resource Areas

chief crop, but flax, oats, and barley are grown on some farms.

The more sloping soils support native grasses and are used as

rangeland.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and

productivity of the soils, management of soil moisture, and

control of saline seeps. Water resource concerns are inefficient

water use on irrigated cropland and excessive amounts of

pesticides, nutrients, and organic material in surface and

ground waters. Plant resource concerns are deterioration of

plant condition, productivity, health, and vigor; noxious and

invasive plants; and wildfires. Animal resource concerns are

inadequate food, cover, and shelter.

Conservation practices on cropland generally include crop

residue management, minimum tillage, cover crops,

stripcropping, nutrient management, soil salinity management,

and pest management. Conservation practices that improve

water use and distribution on irrigated cropland generally

include irrigation water management, irrigation water delivery

systems, and on-farm irrigation practices, such as land leveling,

land smoothing, water-control structures, sprinklers, and

applications of anionic polyacrylamide (PAM) for erosion

control. Noxious and invasive plants can be controlled by pest

management and prescribed grazing. Forest stand improvement

and firebreaks reduce the hazard of wildfires.

Conservation practices on rangeland generally include

prescribed grazing, fencing, and water developments.

Establishment of early and late season pastures supplements

forage production and helps to keep livestock off the rangeland

during critical growth periods. Range improvement practices

and the establishment of food plots benefit wildlife. 

53B—Central Dark Brown Glaciated

Plains

This area (shown in fig. 53B-1) is in North Dakota (77

percent) and South Dakota (23 percent). It makes up about

19,640 square miles (50,900 square kilometers). The city of

Bismarck, North Dakota, is in this MLRA, and Interstate 94

crosses the area, passing through Bismarck. Part of the Fort

Berthold Indian Reservation is in this MLRA. The Lostwood,

Long Lake, Des Lacs, Upper Souris, Lost Lake, Audubon,

Canfield Lake, and Pocasse National Wildlife Refuges are in

this area. Garrison Dam, on the Missouri River north of

Bismarck, formed Lake Sakakawea on the western border of the

MLRA.

Physiography

Almost the entire MLRA is in the Missouri Plateau,

Glaciated, Section of the Great Plains Province of the Interior

Plains. Small portions of the northeast and southeast corners of

Figure 53B-1: Location of MLRA 53B in Land Resource Region F.

the area are in the Western Lake Section of the Central Lowland

Province of the Interior Plains. Elevation ranges from 1,640 to

1,970 feet (500 to 600 meters), increasing gradually from

southeast to northwest. The nearly level to rolling till plains in

this MLRA include kettle holes, kames, moraines, and small

glacial lakes. Moderately steep and steep slopes are adjacent to

the major stream valleys. The southeast corner of the MLRA

consists of nearly level terrain on the west edge of a glacial lake

plain.

The extent of the major Hydrologic Unit Areas (identified

by four-digit numbers) that make up this MLRA is as follows:

Missouri-Oahe (1013), 47 percent; James (1016), 24 percent;

Missouri-Little Missouri (1011), 23 percent; Souris (0901), 4

percent; Red (0902), 1 percent; and Missouri-Poplar (1006),

1 percent. The Missouri River runs parallel with the western

boundary along most of this MLRA. The Des Lacs and

Upper Souris Rivers just touch the northeast corner of the MLRA.

Geology

Almost all of this MLRA is covered by glacial till plains.

Some glaciolacustrine deposits also occur. Kettle holes, kames,

moraines, and small glacial lakes break up the nearly level

terrain. Alluvial deposits are extensive along the Missouri, Des

Lacs, and Souris Rivers but occur in narrow and discontinuous

strips along other streams and rivers. Low terraces occur along

the major rivers.

Climate

The average annual precipitation is 14 to 20 inches (355 to

510 millimeters). About 75 percent of the rainfall occurs as

high-intensity, convective thunderstorms during the growing

season. Winter precipitation is typically snow. The annual

snowfall is 25 to 50 inches (635 to 1,270 millimeters). The

average annual temperature is 38 to 45 degrees F (3 to 7

degrees C). The freeze-free period averages 145 days and ranges

from 130 to 165 days.
of the United States 143

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.6%; ground water, 0.0%

Livestock—surface water, 1.1%; ground water, 0.9%

Irrigation—surface water, 7.4%; ground water, 3.0%

Other—surface water, 85.6%; ground water, 1.5%

The total withdrawals average 545 million gallons per day

(2,060 million liters per day). About 5 percent of the water is

from ground water sources, and 95 percent is from surface

water sources. In most years moisture is inadequate for

maximum crop production. The Missouri River is the only

dependable source of water for irrigation. Thus, only small

areas close to the river and to Lake Sakakawea are irrigated.

Missouri River water is of good quality. The city of Bismarck

obtains its drinking water from the river. In areas away from the

Missouri River, ponds are a source of water for livestock.

Surface water quality outside of the Missouri River is fair or

poor. Limited quantities and high amounts of dissolved solids

limit the use of this water. Rural water systems are improving

the quality of water available for domestic use. These systems

typically obtain their water from the Missouri River and its

reservoirs.

There is a limited supply of ground water in surficial,

unconsolidated aquifers and in the Cenozoic sedimentary

bedrock aquifers beneath the till plains. The unconsolidated

aquifers consist of alluvial deposits in stream valleys and glacial

drift and outwash deposits. Water in the unconsolidated

aquifers is generally very hard and high in sodium and sulfate.

It is used as drinking water in some rural areas. The high

salinity limits its use for irrigation. The sedimentary bedrock

aquifers are the Fort Union aquifer system in the northern twothirds of the MLRA and the Hell Creek-Fox Hills aquifer

system in the southern third. Both of these bedrock aquifer

systems contain soft water with high levels of sodium and

dissolved solids. High salinity limits the use of the water for

irrigation. Naturally occurring selenium levels in the Fort

Union aquifer system are much greater than the recommended

levels for drinking water.

Soils

The dominant soil order in this MLRA is Mollisols. The

soils in the area dominantly have a frigid soil temperature

regime, an ustic or aquic soil moisture regime, and mixed or

smectitic mineralogy. They generally are very deep, well

drained to very poorly drained, and clayey or loamy.

Endoaquolls (Southam series) and Argiaquolls (Parnell series)

formed in alluvium in depressions on till plains, moraines, and

lake plains. Argialbolls (Tonka series) formed in alluvium over

till in depressions on till plains and lake plains. Natrustolls

(Niobell and Noonan series) and Calciustolls (Zahl series)

formed in till on till plains and moraines. Haplustolls formed in

alluvium (Bowdle and Lehr series) and glaciofluvial deposits

(Wabek series) on outwash plains and terraces, in till (Max

series) on till plains, and in silty drift or loess (Bryant series) on

uplands. Argiustolls formed in till (Vida and Williams series)

and mixed till and alluvium (Bowbells series) on till plains,

moraines, and hills.

Biological Resources

This area supports natural prairie vegetation characterized

by western wheatgrass, needleandthread, green needlegrass, and

big bluestem. Little bluestem is an important species on the

more sloping and shallower soils. Prairie cordgrass, northern

reedgrass, and slim sedge are important species on wet soils.

Western snowberry, stiff goldenrod, echinacea, and prairie rose

are commonly interspersed throughout the area.

Some of the major wildlife species in this area are whitetailed deer, red fox, raccoon, muskrat, mink, jackrabbit,

cottontail rabbit, fox squirrel, pheasant, gray partridge, sharptailed grouse, mourning dove, geese, and ducks. The species of

fish in the area include northern pike, walleye, trout, catfish,

bass, bluegill, perch, and bullhead.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 56%

Grassland—private, 36%; Federal, 1%

Urban development—private, 2%

Water—private, 2%

Other—private, 3%

Most of this area is in farms and ranches. Slightly more than

one-half of the area is dry-farmed cropland. Spring wheat is the

chief crop, but flax, oats, barley, and alfalfa are grown on many

farms. The more sloping soils support native grasses and are

used as rangeland.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and

productivity of the soils, and management of soil moisture.

Conservation practices on cropland generally include systems

of crop residue management and no-till systems that conserve

moisture and improve soil quality. Other practices include

vegetative wind barriers, wind stripcropping, grassed

waterways, and nutrient management. 
144 Major Land Resource Areas

Figure 53C-1: Location of MLRA 53C in Land Resource Region F.

53C—Southern Dark Brown Glaciated

Plains

This area is entirely in South Dakota (fig. 53C-1). It makes

up about 3,990 square miles (10,340 square kilometers). It has

no major population centers. U.S. Highways 14, 83, and 212

cross the area, and a portion of the Crow Creek Indian

Reservation is in the area. The area is generally bounded by the

Missouri Breaks to the west and the James Valley Lowlands to

the east and south.

Physiography

The entire MLRA is in the Missouri Plateau, Glaciated,

Section of the Great Plains Province of the Interior Plains.

Elevation ranges from 1,300 to 2,300 feet (395 to 700 meters).

The nearly level to gently rolling till plains include many areas

of potholes. A terminal moraine occurs in the southern end of

the MLRA, north and west of Wessington Springs. Local relief

is about 390 feet (120 meters) from the top of the moraine to

the outwash and till plain to the east. Moderately steep and

steep slopes are adjacent to the major valleys.

The extent of the major Hydrologic Unit Areas (identified

by four-digit numbers) that make up this MLRA is as follows:

Missouri-White (1014), 55 percent; Missouri-Oahe (1013), 35

percent; and James (1016), 10 percent. The headwaters of

many creeks in central South Dakota occur in this high-lying

MLRA.

Geology

This area is covered by glacial till plains broken by

numerous potholes. A terminal moraine occurs in the southern

end of the area. Cretaceous Pierre Shale lies beneath the glacial

deposits in the MLRA.

Climate

The average annual precipitation is 15 to 25 inches (380 to

635 millimeters). About 70 percent of the rainfall occurs as

high-intensity, convective thunderstorms during the growing

season. The annual snowfall is typically 25 to 45 inches (635 to

1,145 millimeters). The average annual temperature is 43 to 49

degrees F (6 to 9 degrees C). The freeze-free period averages

150 days and ranges from 140 to 160 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 10.9%; ground water, 0.0%

Livestock—surface water, 52.6%; ground water, 15.8%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 15.3%; ground water, 5.5%

The total withdrawals average 9 million gallons per day (34

million liters per day). About 21 percent is from ground water

sources, and 79 percent is from surface water sources. In most

years moisture is inadequate for maximum crop production.

Most of the water for livestock comes from dug ponds. Rural

water systems in the area supply domestic water to an

increasing number of farms and communities. Water for these

systems comes from the Missouri River, which has water of

very good quality.

There is a limited supply of ground water in the glacial drift

and alluvial aquifers that occur near the ground surface. These

aquifers consist of unconsolidated sand and gravel. The fresh to

saline water is hard and is a calcium, bicarbonate, and sulfate

type. The aquifers provide water primarily for domestic use and

livestock. The level of total dissolved solids typically exceeds

the recommended levels for drinking water. Many private wells

have high levels of nitrate plus nitrite. Most of this

contamination occurs where the wells are located downslope

from septic tank absorption fields, feedlots, barnyards, and

fertilizer storage areas.

Soils

The dominant soil orders in this MLRA are Mollisols and

Inceptisols. The soils in the area dominantly have a mesic soil

temperature regime, an ustic soil moisture regime, and mixed or

smectitic mineralogy. They are very deep, generally well

drained or moderately well drained, and loamy or clayey.

Haplustolls and Natrustolls (Cavo and Java series) formed in till

on till plains. Argiustolls formed in loess on uplands (Agar

series), in till on till plains and uplands (Glenham, Prosper, and

Raber series), in colluvium and/or alluvium on footslopes and

in swales (Mobridge and Onita series), and in silty sediments on
of the United States 145

uplands (Eakin and Highmore series). Natraquolls (Hoven

series) formed in alluvium in basins. Argialbolls (Tetonka

series) formed in alluvium in depressions. Calciustepts (Betts

series) formed in till on moraines.

Biological Resources

This area supports natural prairie vegetation. Western

wheatgrass, big bluestem, needleandthread, and green

needlegrass are the dominant species. Little bluestem, sideoats

grama, and prairie sandreed are important species on the steeper

sites. Western snowberry and prairie rose are commonly

interspersed throughout the area.

Some of the major wildlife species in this area are mule deer,

white-tailed deer, coyote, bobcat, cottontail, sharp-tailed grouse,

gray partridge, mourning dove, pheasant, geese, and ducks. The

species of fish in the area include largemouth bass, bluegill,

bullhead, and yellow perch.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 54%

Grassland—private, 41%

Urban development—private, 2%

Water—private, 1%

Other—private, 2%

Most of this area is in farms and ranches. Slightly more than

one-half of the area is dry-farmed cropland. Winter wheat is the

chief cash crop. Corn, sunflowers, grain sorghum, oats, and

alfalfa are grown on many farms. The more sloping soils are

used as rangeland.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and

productivity of the soils, and management of soil moisture.

Conservation practices on cropland generally include systems

of crop residue management and no-till systems that conserve

moisture and improve soil quality. Other practices include

windbreaks, vegetative wind barriers, wind stripcropping, and

nutrient management. 

Figure 54-1: Location of MLRA 54 in Land Resource Region F.

54—Rolling Soft Shale Plain

This area (shown in fig. 54-1) is in North Dakota (64

percent), South Dakota (33 percent), and Montana (3 percent).

It makes up about 29,280 square miles (75,870 square

kilometers). The cities of Dickinson and Mandan, North

Dakota, and the towns of Lemmon and Faith, South Dakota, are

in this MLRA. Interstate 94 crosses the northern half of the area,

and U.S. Highways 12, 85, and 212 are in the area. The

Missouri River is at the eastern edge of the area, and Lake

Sakakawea, formed by the Garrison Dam, is the northeastern

boundary of the area. Grand River National Grasslands, most of

the Standing Rock Indian Reservation, and the northwest third

of the Cheyenne River Indian Reservation are in the southern

part of the area.

Physiography

This area is in the Missouri Plateau, Unglaciated, and

Missouri Plateau, Glaciated, Sections of the Great Plains

Province of the Interior Plains. It is dominantly unglaciated, but

the eastern and northern edges have been glaciated. The area is

on an old, moderately dissected, rolling plain with some local

badlands, buttes, and isolated hills. Terraces are adjacent to

broad flood plains along most of the major drainages. Elevation

is 1,650 feet (505 meters) in the east with a gradual slope to

about 3,600 feet (1,100 meters) in the west. Maximum local

relief is about 330 feet (100 meters), but relief is considerably

lower in most of the area.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Missouri-Oahe (1013), 73 percent; Missouri-Little Missouri

(1011), 17 percent; Cheyenne (1012), 6 percent; and Lower

Yellowstone (1010), 4 percent. The Knife, Heart, Cannonball,

and Cedar Rivers, which are major tributaries of the Missouri

River in North Dakota, drain this area. Also, the Grand and

Moreau Rivers in South Dakota drain the southern part of the

area.

Geology

This area is underlain by soft, calcareous shales, siltstones,

and sandstones of the Tertiary Fort Union Formation and the

Fox Hills and Hell Creek units. The principal sources of ground

water in the area are in these rocks. Impermeable Cretaceous

shale underlies these aquifers. The northern and eastern parts of

the area have a glacially modified topography and in places are

covered by thin layers of glacial drift.
146 Major Land Resource Areas

Climate

The average annual precipitation is 14 to 18 inches (355 to

455 millimeters). Most of the rainfall occurs as convective

thunderstorms during the growing season. About half of the

annual precipitation occurs as snow in winter. The average

annual temperature is 38 to 46 degrees F (3 to 8 degrees C). The

freeze-free period averages 150 days and ranges from 130 to

165 days. It is shortest in the southern part of the area and

longest in the northern part.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 1.1%; ground water, 1.3%

Livestock—surface water, 1.3%; ground water, 0.3%

Irrigation—surface water, 6.3%; ground water, 6.7%

Other—surface water, 82.5%; ground water, 0.6%

The total withdrawals average 415 million gallons per day

(1,570 million liters per day). About 9 percent is from ground

water sources, and 91 percent is from surface water sources. In

most years the supply of moisture is inadequate for maximum

crop production. Water for irrigation is available in quantity

only from the Missouri River and a few of its larger tributaries.

The surface water is generally soft and is typically a sodium

bicarbonate type. Water for livestock is stored primarily in

small reservoirs. The Missouri River water is used dominantly

as cooling water for thermoelectric power generation.

Small areas of sand and gravel buried beneath valley floors

in this MLRA yield moderate quantities of hard water. Ground

water from the Tertiary units is generally hard or very hard.

Sodium, sulfate, and bicarbonate are the major ions in the

ground water. The Fort Union Formation in North Dakota yields

soft water, but the water is high in content of selenium. The

content of molybdenum is high in the water in the shallow

aquifers in South Dakota. High levels of selenium and

molybdenum affect the health of humans and livestock. Ground

water is scarce or does not occur in areas underlain by shale.

Farms, ranches, and small communities use ground water for

most purposes, except for irrigation.

Soils

The dominant soil orders in this MLRA are Mollisols and

Entisols. The soils in the area dominantly have a frigid soil

temperature regime, an ustic soil moisture regime, and mixed or

smectitic mineralogy. They are shallow to very deep, generally

somewhat excessively drained to moderately well drained, and

loamy or clayey. Haplustolls formed in residuum on uplands

(Amor and Vebar series) and in alluvium on stream terraces and

in upland drainageways (Parshall series). Natrustolls (Belfield,

Daglum, and Rhoades series) formed in residuum and/or

alluvium on uplands and stream terraces and in upland

drainageways. Calciustolls (Chama series), Ustorthents (Cabba

series), and Ustipsamments (Flasher series) formed in residuum

and/or colluvium on uplands. Argiustolls formed in residuum

on uplands (Morton, Reeder, and Regent series) and in till on

till plains and moraines (Williams series).

Biological Resources

This area supports natural prairie vegetation characterized

by western wheatgrass, needleandthread, green needlegrass, and

blue grama. Little bluestem, prairie sandreed, and sideoats

grama are important species on shallow soils. Prairie rose,

leadplant, and patches of western snowberry are interspersed

throughout the area. Green ash, chokecherry, and buffaloberry

occur in draws and narrow valleys.

Some of the major wildlife species in this area are whitetailed deer, mule deer, pronghorn antelope, red fox, coyote,

white-tailed jackrabbit, prairie dog, ring-necked pheasant, gray

partridge, sharp-tailed grouse, ducks, and geese. The species of

fish in the area include rainbow trout, walleye, smallmouth

bass, bluegill, yellow perch, and northern pike. Fishing is

limited mostly to rivers and constructed impoundments.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 38%; Federal, 1%

Grassland—private, 50%; Federal, 4%

Forest—private, 1%

Urban development—private, 1%

Water—private, 3%

Other—private, 2%

Farms and ranches make up nearly all of this area. They

produce a combination of cash-grain crops and livestock. More

than one-half of the area supports native grasses and shrubs that

are grazed. About one-third of the area is used for dry-farmed

small grains, such as wheat, barley, oats, rye, and flax. Corn for

grain and silage, sunflowers, and alfalfa also are important

crops. Some small tracts on the bottom land along the Missouri

River are irrigated.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and

productivity of the soils, management of soil moisture, and

control of saline seeps. Conservation practices on cropland

generally include systems of crop residue management and

minimum-till and no-till systems that reduce the need for

summer fallow tillage. Other practices include cover crops,

windbreaks, vegetative wind barriers, wind stripcropping,

nutrient management, and soil salinity management.

Conservation practices on rangeland generally include

prescribed grazing, fencing, and water developments. 
of the United States 147

Figure 55A-1: Location of MLRA 55A in Land Resource Region F.

55A—Northern Black Glaciated Plains

This area is entirely in North Dakota (fig. 55A-1). It makes

up about 12,765 square miles (33,075 square kilometers).

Minot and Devils Lake are in this MLRA. The International

Peace Garden is in the north-central part of the area, on the

Canadian border. The Geographical Center of North America is

in the south-central part of the MLRA. The Turtle Mountains

and Fort Totten (or Devils Lake Sioux) Indian Reservations are

in this MLRA. The Upper Souris, J. Clark Salyer, Rock Lake,

Brumba, Silver Lake, and Lake Alice National Wildlife Refuges

also are in this MLRA.

Physiography

All of this area is in the Western Lake Section of the Central

Lowland Province of the Interior Plains. Elevation ranges from

1,200 to 2,550 feet (365 to 775 meters), increasing from east to

west. The mostly nearly level to gently rolling till plains

include areas of kettle holes, kames, and moraines. Some of the

depressions contain lakes. Also in the area are nearly level

glacial lake plains and some steep slopes adjacent to streams.

The Turtle Mountains, in the north-central part of the MLRA,

on the Canadian border, are approximately 1,950 to 2,550 feet

(595 to 775 meters) in elevation, rising approximately 500 feet

(150 meters) above the adjacent till plain.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Souris (0901), 56 percent, and Red (0902), 44 percent. The

Souris River is in this MLRA. The headwaters of the Sheyenne

River, a major tributary to the Red River of the North, are in the

south-central part of this area.

Geology

This MLRA is covered by glacial till plains. It also has some

glaciolacustrine deposits, kettle holes, kames, moraines, and

glacial lake plains. The Turtle Mountains are remnants of a

glacial moraine in this MLRA. Alluvial deposits are extensive

along the Souris River but occur in narrow and discontinuous

strips along other streams and rivers. Low terraces are along the

major rivers.

Climate

The average annual precipitation is 14 to 19 inches (355 to

485 millimeters). About 75 percent of the rainfall occurs as

high-intensity, convective thunderstorms during the growing

season. Winter precipitation is typically snow. The annual

snowfall is 25 to 50 inches (635 to 1,270 millimeters). The

average annual temperature is 36 to 41 degrees F (2 to 5

degrees C). The freeze-free period averages 140 days and ranges

from 125 to 155 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.3%; ground water, 0.1%

Livestock—surface water, 0.3%; ground water, 0.4%

Irrigation—surface water, 0.4%; ground water, 0.4%

Other—surface water, 97.4%; ground water, 0.6%

The total withdrawals average 760 million gallons per day

(2,875 million liters per day). About 2 percent is from ground

water sources, and 98 percent is from surface water sources. In

some years precipitation is inadequate for maximum crop

production. The few perennial streams in the area are widely

spaced and are little used for irrigation. Water for livestock is

stored in ponds and small reservoirs on individual farms and

ranches. There are a number of reservoirs on the Souris River.

Some of the reservoir water is used for cooling thermoelectric

power plants. The surface water is of good quality but at times

is limited in quantity in most of the area.

Ground water is plentiful in unconsolidated sand and gravel

deposits in glacial drift, but the water is very hard and generally

has a mixture of calcium bicarbonate and sodium bicarbonate

or chloride. It is used as drinking water in rural areas. The

sedimentary bedrock aquifers are the Hell Creek-Fox Hills

aquifer system in the western half of the MLRA and the Great

Plains (Dakota) aquifer system in the eastern half. The Hell

Creek-Fox Hills aquifer system contains soft water with high

levels of sodium and dissolved solids. High salinity limits the

use of this water for irrigation. The shale directly under the

glacial deposits in the eastern half of the MLRA is not an

aquifer. The Great Plains (Dakota) aquifer system is a sandstone

unit beneath the shale. It yields large quantities of highly

mineralized artesian water. Few wells have been drilled into

this unit, however, because of its depth and poor-quality

water.
148 Major Land Resource Areas

55B—Central Black Glaciated Plains

This area (shown in fig. 55B-1) is in North Dakota (79

percent) and South Dakota (21 percent). It makes up about

17,155 square miles (44,455 square kilometers). The cities of

Jamestown, North Dakota, and Aberdeen, South Dakota, are in

this MLRA. Interstate 94 passes through Jamestown in the

northern half of the area. Numerous national wildlife refuges are

in this MLRA, including the Lambs Lake, Johnson Lake,

Sibley Lake, Buffalo Lake, Arrowwood, Tewaukon, Chase

Lake, and Lake George National Wildlife Refuges in North

Dakota and the Sand Lake National Wildlife Refuge in South

Dakota.

Physiography

Almost the entire MLRA is in the Western Lake Section of

the Central Lowland Province of the Interior Plains. Elevation

ranges from 1,000 to 2,050 feet (305 to 625 meters), increasing

from east to west. This area is characterized by nearly level to

gently rolling till plains and many poorly defined drainage

channels. Steep slopes adjacent to the main streams and the

glacial lake plains break up the nearly level to gently rolling

terrain. The eastern edge of the part of the area in North Dakota

Soils

The dominant soil order in this MLRA is Mollisols. The

soils in the area dominantly have a frigid soil temperature

regime, a udic or aquic soil moisture regime, and mixed or

smectitic mineralogy. They generally are very deep, well

drained to poorly drained, and loamy or clayey. Hapludolls

formed in glacial till on till plains and moraines (Barnes,

Emrick, and Heimdal series), in sandy sediments on lake plains

and outwash plains (Arvilla and Hecla series), in mixed till and

alluvium on till plains (Svea series), and in loamy sediments on

uplands (Swenoda series). Calciudolls (Buse series) formed in

glacial till on till plains and moraines. Calciaquolls formed on

lake plains (Bearden and Hegne series) and on till plains

(Hamerly and Vallers series). Argiaquolls (Parnell series) and

Argialbolls (Tonka series) formed in local alluvium in

depressions on till plains.

Biological Resources

This area supports natural prairie vegetation characterized by

western wheatgrass, green needlegrass, needleandthread, and

blue grama. Little bluestem is an important species on the more

sloping and shallower soils. Prairie cordgrass, northern

reedgrass, big bluestem, and slough sedge are important species

on wet soils. Western snowberry, leadplant, and prairie rose are

commonly interspersed throughout the area. A small part of the

area can support forest vegetation characterized by oak and

aspen.

Some of the major wildlife species in this area are whitetailed deer, coyote, red fox, badger, beaver, raccoon, skunk,

muskrat, mink, snowshoe hare, white-tailed jackrabbit,

cottontail, fox squirrel, sharp-tailed grouse, gray partridge,

ruffed grouse, mourning dove, pheasant, geese, and ducks. The

species of fish in the area include northern pike, walleye, perch,

trout, and bullhead.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 75%

Grassland—private, 14%; Federal, 2%

Forest—private, 2%

Urban development—private, 2%

Water—private, 2%

Other—private, 2%

Nearly all of this area is in farms and ranches. About threefourths of the area is dry-farmed cropland. Cash-grain wheat

production is the principal enterprise on many farms, but other

cash grains and feed grains, such as wheat, durum, barley,

oats, and flax, also are grown. Other crops grown include hay,

canola, peas, forage crops, corn for grain and silage, and

sunflowers. The more sloping and shallower or sandy soils

are used as native range. Less than one-tenth of the area is

forested.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and

productivity of the soils, management of soil moisture, salinity

around wetland borders, and aggregate stability. Conservation

practices on cropland generally include crop residue

management, no-till and other conservation tillage systems,

conservation cropping systems that eliminate the need for

fallowing, cover crops, nutrient management, and pest

management. 

Figure 55B-1: Location of MLRA 55B in Land Resource Region F.
of the United States 149

used as cooling water in the generation of electricity from

burning fossil fuels.

Ground water occurs in consolidated rocks and glacial drift

in this area. The water from the glacial drift is typically fresh or

saline and hard or very hard. The freshwater is high in calcium,

bicarbonate, and sulfate. The saline water is high in sodium and

sulfate. Shallow ground water is used as drinking water in some

rural areas. The high salinity in some aquifers limits the use of

the water for irrigation, but the aquifers provide water for

livestock. One sedimentary bedrock aquifer is Dakota

Sandstone in North Dakota. It is about 1,000 feet (305 meters)

beneath the land surface.

Two additional sedimentary bedrock aquifers, the NiobraraCodell and Dakota-Newcastle, occur at a depth of about 1,100

feet (335 meters) in South Dakota. Hell Creek-Fox Hills

sedimentary bedrock is under the glacial deposits in the

northwest corner of the MLRA. This aquifer system contains

soft water with high levels of sodium and dissolved solids.

High salinity limits the use of the water for irrigation. The

sedimentary bedrock aquifers yield large quantities of slightly

saline or moderately saline artesian water. Water from the

Niobrara-Codell aquifer is used for domestic purposes and for

livestock, but the level of total dissolved solids is too high for

the water to be used for irrigation. Water from the DakotaNewcastle aquifer is used only for livestock.

Soils

The dominant soil order in this MLRA is Mollisols. The

soils in the area dominantly have a frigid soil temperature

regime, a udic or aquic soil moisture regime, and mixed or

smectitic mineralogy. They generally are very deep, well

drained to poorly drained, and loamy or clayey. Hapludolls and

Argiudolls formed in glacial till on till plains and moraines

(Barnes, Emrick, and Forman series), in sandy sediments on

lake plains and outwash plains (Arvilla and Hecla series), in

silty lacustrine deposits on lake plains (Great Bend, Beotia, and

Harmony series), in mixed till and alluvium on till plains (Svea

series), and in loamy sediments on uplands (Swenoda series).

Calciudolls (Buse series) formed in glacial till on till plains and

moraines. Calciaquolls formed on lake plains (Bearden and

Hegne series) and on till plains (Hamerly and Vallers series).

Argiaquolls (Parnell series) and Argialbolls (Tonka series)

formed in local alluvium in depressions on till plains.

Biological Resources

This area supports natural prairie vegetation characterized

by western wheatgrass, green needlegrass, needleandthread, and

blue grama. Little bluestem and sideoats grama are important

species on the more sloping and shallower soils. Prairie

cordgrass, northern reedgrass, big bluestem, and slough sedge

and the part of the area in South Dakota are adjacent to glacial

Lake Agassiz. A continental drainage divide occurs in the eastcentral part of the MLRA.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows: Red

(0902), 48 percent; James (1016), 46 percent; and Souris

(0901), 6 percent. The James River flows south through all of

this area and joins the Missouri River, and the Sheyenne River

flows east and north and joins the Red River of the North. The

James River is the longest unnavigable river in the United

States.

Geology

This MLRA is covered by glacial till plains that include

glacial lacustrine deposits. Glacial deposits in kettle holes,

kames, and moraines break up the till plain. One of the major

river systems in this area is the James River, which was carved

by floodwaters draining glacial Lake Dakota. Its valley is filled

with glacial outwash and alluvial deposits. A high terrace scarp

separates the valley floor from the surrounding land. Alluvial

deposits and low terraces occur along the Sheyenne River.

Climate

The average annual precipitation in most of this area is 16 to

21 inches (405 to 535 millimeters). Almost 75 percent of the

rainfall occurs as high-intensity, convective thunderstorms

during the growing season. Winter precipitation is typically

snow. The annual snowfall is 25 to 50 inches (635 to 1,270

millimeters). The average annual temperature is 37 to 44

degrees F (3 to 7 degrees C). The freeze-free period averages

150 days and ranges from 135 to 165 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 2.3%; ground water, 1.2%

Livestock—surface water, 0.1%; ground water, 0.7%

Irrigation—surface water, 2.8%; ground water, 4.4%

Other—surface water, 87.5%; ground water, 1.1%

The total withdrawals average 685 million gallons per day

(2,590 million liters per day). About 7 percent is from ground

water sources, and 93 percent is from surface water sources. In

some years precipitation is inadequate for maximum crop

production. Perennial streams are few and widely spaced and

are little used for irrigation. Water for livestock is stored in

ponds and small reservoirs on individual farms and ranches.

The surface water is of fair or good quality but at times is

limited in quantity. Most of the surface water in this MLRA is
150 Major Land Resource Areas

55C—Southern Black Glaciated Plains

This area is entirely in South Dakota (fig. 55C-1). It makes

up about 10,835 square miles (28,075 square kilometers). The

cities of Huron, Mitchell, and Yankton are in this MLRA.

Interstate 90 bisects the area. The Lake Andes National Wildlife

Refuge and the Yankton Indian Reservation are in this MLRA.

Physiography

Three-fourths of this MLRA is in the Western Lake Section

of the Central Lowland Province of the Interior Plains. The

southwest quarter is in the Missouri Plateau, Glaciated, Section

of the Great Plains Province of the Interior Plains. Elevation

ranges from 1,310 to 1,970 feet (400 to 600 meters). Most of the

are important species on wet soils. Western snowberry,

leadplant, and prairie rose are common shrub species

interspersed throughout the area.

Some of the major wildlife species in this area are whitetailed deer, coyote, red fox, badger, raccoon, muskrat, mink,

white-tailed jackrabbit, cottontail rabbit, pheasant, gray

partridge, sharp-tailed grouse, mourning dove, geese, various

species of grassland birds, shore birds, amphibians, and ducks.

The species of fish in the area include northern pike, perch,

walleye, crappie, bluegill, and smallmouth bass.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 76%

Grassland—private, 15%; Federal, 1%

Urban development—private, 3%

Water—private, 1%

Other—private, 4%

About three-fourths of this area is dry-farmed cropland.

Cash-grain production is the principal enterprise on many

farms. Less than one-fifth of the area, consisting of the more

sloping and shallower soils, is used for livestock production on

native range or woodland. The dry-farmed crops are principally

small grains, such as wheat, durum, and barley, corn for grain,

and soybeans. Flax, canola, peas, dry edible beans, sunflowers,

forage crops, and corn for silage also are grown.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and

productivity of the soils, management of soil moisture, and

salinity around wetland borders. Conservation practices on

cropland generally include crop residue management, no-till

and other conservation tillage systems, conservation cropping

systems that eliminate the need for fallowing, cover crops,

nutrient management, and pest management. 

Figure 55C-1: Location of MLRA 55C in Land Resource Region F.

area consists of nearly level to undulating till plains with

potholes and moraines. Steep slopes are adjacent to the major

streams.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

James (1016), 66 percent; Missouri-Big Sioux (1017), 19

percent; and Missouri-White (1014), 15 percent. The Missouri

River runs along the southwest edge of this MLRA, and the

James River flows north to south down the center of the MLRA.

Geology

Most of this MLRA is on nearly level to undulating glacial

till plains interrupted by steeper slopes adjacent to streams and

moraines. Minor moraines are in scattered areas throughout the

MLRA, and stagnation moraines are dominant in the

southwestern part. Small areas of outwash are adjacent to the

minor moraines. The James River is an under-fit stream. Its

valley was carved by floodwaters draining glacial Lake Dakota

and is filled with glacial outwash and alluvial deposits. The

Missouri River flows in a trench cut by glacial meltwater in the

adjacent MLRA 63B. A high terrace scarp separates the valley

floor along the Missouri and James Rivers from the surrounding

land. The transitional area between the uplands and the valley

floors of the two rivers is deeply eroded. This area is called the

“breaks” along the Missouri River.

Climate

The average annual precipitation is 18 to 25 inches (455 to

635 millimeters). About 70 percent of the rainfall occurs as

high-intensity, convective thunderstorms during the growing

season. Winter precipitation is typically snow. The annual

snowfall is 23 to 46 inches (585 to 1,170 millimeters). The

average annual temperature is 43 to 49 degrees F (6 to 10

degrees C). The freeze-free period averages 165 days and ranges

from l40 to 190 days.
of the United States 151

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 5.6%; ground water, 6.9%

Livestock—surface water, 0.7%; ground water, 2.4%

Irrigation—surface water, 21.5%; ground water, 52.9%

Other—surface water, 1.0%; ground water, 9.0%

The total withdrawals average 90 million gallons per day

(340 million liters per day). About 71 percent is from ground

water sources, and 29 percent is from surface water sources. In

most years precipitation is inadequate for maximum crop

production. Perennial streams are few and widely spaced and

are little used for irrigation. Water for livestock is stored in

ponds and small reservoirs on individual farms and ranches.

The surface water is of fair or poor quality. Limited quantities

and high amounts of dissolved solids limit the use of the water.

Missouri River water is of good quality. It meets national

drinking water standards. Water from reservoirs on the Missouri

River is used for irrigation on the adjacent upland soils.

There is a limited supply of ground water in the shallow,

unconsolidated sand and gravel deposits that make up the

glacial drift and alluvial aquifers. A significant glacial outwash

deposit is beneath the flood plain along the lower reaches of the

James River in the southern part of the MLRA. A significant

acreage is irrigated by this local aquifer. The fresh or saline

water is hard and is a calcium, bicarbonate, and sulfate type.

The ground water is used primarily for domestic supply,

livestock, and irrigation. The level of total dissolved solids

typically exceeds the recommended levels for drinking water.

Many private wells have high levels of nitrate plus nitrite. Most

of this contamination occurs in areas where the wells are

located downslope from septic tank absorption fields, feedlots,

barnyards, and fertilizer storage areas.

A confining layer of shale beneath the glacial deposits

overlies two sedimentary bedrock aquifers in this MLRA, the

Niobrara-Codell and Dakota-Newcastle. These aquifers are at a

depth of about 1,100 feet (335 meters). The shale lying directly

beneath the glacial deposits is not an aquifer. The sedimentary

bedrock aquifers yield large quantities of slightly saline or

moderately saline artesian water. The water is very hard and is

typically a sodium sulfate type. The Niobrara-Codell aquifer

provides water for domestic uses and livestock, but the level of

total dissolved solids is too high for the water to be used for

irrigation. Water from the Dakota-Newcastle aquifer is used

only for livestock.

Soils

The dominant soil order in this MLRA is Mollisols. The

soils in the area dominantly have a mesic soil temperature

regime, an ustic soil moisture regime, and mixed or smectitic

mineralogy. They generally are very deep, well drained to

poorly drained, and clayey or loamy. Calciustolls (Ethan series)

and Calciustepts (Betts series) formed in till on moraines and

the steeper slopes. Natrustolls (Dudley, Stickney, and Jerauld

series) formed in till on till plains. Haplustolls formed in till on

till plains (Bonilla and Clarno series), in glaciofluvial deposits

on outwash plains (Hand, Delmont, and Enet series), and in

sandy eolian material (Forestburg series). Argiustolls formed in

till (Beadle, Houdek, and Prosper series), silty drift (Highmore

series), and a silty mantle over till (Eakin series) on till plains

and hills and in alluvium (Onita series) on fans and footslopes

and in swales. Argialbolls (Tetonka series), Argiaquolls

(Worthing series), and Natraquolls (Hoven series) formed in

alluvium in depressions on till plains.

Biological Resources

This area supports natural prairie vegetation characterized

by western wheatgrass, green needlegrass, needleandthread, and

porcupinegrass. Big bluestem is an important species on soils

that receive beneficial overflow or are subirrigated. Prairie

cordgrass, reed canarygrass, and western wheatgrass are

dominant on the poorly drained soils.

Some of the major wildlife species in this area are mule deer,

white-tailed deer, fox, beaver, raccoon, opossum, muskrat,

mink, cottontail, tree squirrel, pheasant, partridge, bobwhite

quail, mourning dove, geese, and ducks. The species of fish in

the area include bluegill, bass, carp, shad, channel catfish, black

bullhead, crappie, walleye, and northern pike.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 58%

Grassland—private, 34%; Federal, 1%

Urban development—private, 3%

Water—private, 1%

Other—private, 3%

Nearly all this area is in farms and ranches. Slightly more

than one-half of the area is dry-farmed cropland. Corn,

soybeans, small grains, and alfalfa are the principal crops. Grain

sorghum also is grown. About one-third of the area is used as

native range or tame pasture.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and

productivity of the soils, and management of soil moisture.

Conservation practices on cropland generally include systems

of crop residue management and no-till systems that conserve

moisture and improve soil quality. Other practices include

vegetative wind barriers, wind stripcropping, grassed

waterways, and nutrient management. 
152 Major Land Resource Areas

Figure 56-1: Location of MLRA 56 in Land Resource Region F.

56—Red River Valley of the North

This area (shown in fig. 56-1) is primarily in Minnesota (57

percent) and North Dakota (43 percent), but a small portion (61

square miles, or 158 square kilometers) is in South Dakota. The

area makes up about 16,300 square miles (42,235 square

kilometers). The cities of Grand Forks and Fargo, North Dakota,

and the towns of Thief River Falls, Crookston, and Moorhead,

Minnesota, are in this MLRA. Interstate 29 parallels the west

bank of the Red River of the North along the length of this area.

This MLRA has numerous State parks, the Ardoch and Kellys

Slough National Wildlife Refuges, and the Sheyenne National

Grasslands.

Physiography

This area is in the Western Lake Section of the Central

Lowland Province of the Interior Plains. It is on a nearly level

glacial lake plain bordered on the east by outwash plains,

gravelly beaches, and dunes. Elevation is generally 1,000 feet

(305 meters), but it gradually decreases to 650 feet (200 meters)

to the north.

The only Hydrologic Unit Area (identified by a four-digit

number) that makes up this MLRA is Red (0902). The Red

River bisects this MLRA. It is formed where the Otter Tail and

Bois de Sioux Rivers meet at Wahpeton, North Dakota. The

Sheyenne River is the largest tributary to the Red River in the

part of the area in North Dakota, and the Red Lake River is the

largest tributary in the part in Minnesota.

Geology

This area is the bed of glacial Lake Agassiz. It is a glacial

lake plain with remnants of gravelly beaches marking its

eastern border. The erosion resistance of the gravel causes the

beaches to appear as ridges in an otherwise flat landscape.

Some dunes have formed in areas near the beaches where sand

has been deposited.

Climate

The average annual precipitation in this area is 18 to 23

inches (455 to 585 millimeters). About 70 percent of the rainfall

occurs as high-intensity, convective thunderstorms during the

growing season. Winter precipitation typically occurs as 25 to

50 inches (630 to 1,270 millimeters) of snow, which accounts

for about 15 percent of the annual precipitation. The average

annual temperature is 36 to 44 degrees F (2 to 7 degrees C),

decreasing from south to north. The freeze-free period averages

145 days and ranges from 125 to 170 days. It is shortest in the

northern part of the area and longest in the southern part.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 8.8%; ground water, 6.3%

Livestock—surface water, 0.5%; ground water, 1.0%

Irrigation—surface water, 2.8%; ground water, 4.3%

Other—surface water, 76.1%; ground water, 0.3%

The total withdrawals average 330 million gallons per day

(1,250 million liters per day). About 12 percent is from ground

water sources, and 88 percent is from surface water sources. In

years of normal precipitation, moisture is sufficient for the

crops commonly grown in the area, but some areas are irrigated.

Surface water is more abundant in Minnesota than in North

Dakota. The surface water is used primarily for municipal,

commercial, and industrial supplies, but some is used for

irrigation. Water from the Red River and its tributaries in North

Dakota is generally suitable for drinking. Most of the

tributaries on the Minnesota side of the Red River are saline.

The water in the Wild Rice and Goose Rivers, for example,

exceeds the drinking water standard for sulfate. Late winter and

early spring flooding along the Red River is a constant threat.

In the southern part of the area, thaws occur earlier in spring,

while the river’s outlet in Canada is still frozen. The flat slope

of the Red River exacerbates the flooding problems. In most

areas drainage systems are needed so that farming operations

can be started when the temperature is favorable.

Ground water is not used to a great extent in this MLRA

because of the relative abundance of better quality surface

water. Almost all of the rural domestic water used in the MLRA,

however, is ground water. The city of Fargo pumps public water

from a buried glacial deposit of sand and gravel. The surficial

and buried glacial outwash deposits are the primary aquifers in

this area. Ground water from these aquifers is hard or very hard,

and much of the ground water in the area exceeds the secondary
of the United States 153

national drinking water standard of 500 parts per million

(milligrams per liter) total dissolved solids. The water in the

Cretaceous sedimentary bedrock aquifers that lie beneath the

glacial deposits and the Precambrian crystalline igneous and

metamorphic rocks that lie beneath the sedimentary rocks is

unsuitable for most uses, except for livestock watering. The

latter aquifer has low-yield wells.

Soils

The dominant soil orders in this MLRA are Mollisols and

Vertisols. The soils in the area dominantly have a frigid soil

temperature regime, an aquic or udic soil moisture regime, and

mixed or smectitic mineralogy. They are very deep, somewhat

poorly drained to very poorly drained, and loamy or clayey.

Calciaquolls formed in lacustrine or outwash sediments on

glaciolacustrine and outwash plains (Bearden, Colvin,

Glyndon, Grimstad, Ulen, and Wheatville series) and in till on

till plains (Hamerly, Vallers, Roliss, and Kratka series).

Argiudolls (Doran series) formed in water-worked till or

lacustrine sediments over till on glaciolacustrine plains.

Hapludolls (Embden, Gardena, and Overly series), Epiaquerts

(Fargo and Northcote series), Calciaquerts (Hegne series), and

Epiaquolls (Perella series) formed in lacustrine sediments on

glaciolacustrine plains.

Biological Resources

This area supports natural prairie vegetation characterized

by big bluestem, switchgrass, Indiangrass, and little bluestem.

Bur oak, American basswood, American elm, eastern

cottonwood, green ash, and willows grow in drainageways.

Shrubs include American plum, common chokecherry, and

western snowberry.

Some of the major wildlife species in this area are whitetailed deer, red fox, raccoon, muskrat, mink, jackrabbit,

cottontail, tree squirrel, pheasant, gray partridge, sharp-tailed

grouse, mourning dove, geese, and ducks. The species of fish in

the area include perch, bullhead, northern pike, walleye, and

catfish.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 79%

Grassland—private, 4%; Federal, 2%

Forest—private, 6%

Urban development—private, 3%

Water—private, 1%

Other—private, 5%

Nearly all of this area is in farms and ranches. More than

three-fourths of the area is dry-farmed cropland. Important cash

crops are spring wheat, soybeans, potatoes, sugar beets, corn,

oil-producing crops, and edible beans. Less than one-tenth of

the area is forested. The forestland is in the northeastern part of

the area.

The major soil resource concerns in this area are wind

erosion, deposition of sediment by floodwater, maintenance

of the content of organic matter and productivity of the soils,

management of soil moisture, salinity in selected areas,

surface compaction, and aggregate stability. The efficient use of

water is a major concern on irrigated land. Conservation

practices on cropland generally include crop residue

management, conservation tillage systems, conservation

cropping systems, field windbreaks, herbaceous wind barriers,

filter strips, cover crops, nutrient management, and pest

management. 

155

Figure G-1: Location of Land Resource Region G.

G—Western Great Plains Range and

Irrigated Region

This region (shown in fig. G-1) is in Montana (22 percent),

New Mexico (16 percent), South Dakota (16 percent), Colorado

(15 percent), Nebraska (15 percent), Wyoming (14 percent),

North Dakota (1 percent), and Texas (1 percent). Very small

portions of Oklahoma and Kansas also are in this region. The

region makes up 213,945 square miles (554,395 square

kilometers).

This region forms the western edge of the Great Plains (fig.

G-2). It butts up against the foothills of the Rocky Mountains.

It is an elevated piedmont plain dissected by numerous rivers

flowing to the east. Slopes generally are gently rolling or

rolling. Flat-topped, steep-sided buttes commonly rise above

the general level of the plain. Badlands occur in some areas.

The amount of precipitation in this region typically is low

because much of the region is on the leeward side of mountains.

The average annual precipitation is 13 to 22 inches (330 to 560

millimeters) in most of the region. Most of the precipitation

falls during spring thunderstorms and winter snowfalls. The

average annual temperature ranges from 44 to 51 degrees F (7

to 11 degrees C) in most of the region. The freeze-free period

ranges from 135 to 185 days, increasing in length from north to

south.

The total withdrawals of freshwater in this region average

about 13,830 million gallons per day (52,345 million liters per

day). About 77 percent is from surface water sources, and 23

percent is from ground water sources. About 84 percent of the

water is used for irrigation.

The soils in this region are dominantly Entisols and

Mollisols. Other notable orders are Alfisols, Aridisols,

Inceptisols, and some Vertisols. The dominant suborders are

Ustorthents, Torriorthents, Haplustolls, and Argiustolls. Other

notable suborders are Haplargids, Haplustalfs, and Haplustepts.

Most of the soils in the region have a mesic or frigid soil

temperature regime and an ustic or aridic soil moisture regime.

Most have mixed or smectitic mineralogy, but some have

carbonatic mineralogy.

About 88 percent of the land in this region is privately

owned. The native vegetation consists mainly of short prairie

grasses, but some large areas support mid and tall prairie

grasses. Ponderosa pine and pinyon-juniper forests occur at the
156 Major Land Resource Areas

Figure G-2: An area of Land Resource Region G.

higher elevations. The dominant land use is grazing by cattle

and by some sheep. Dry-farmed winter wheat and other small

grains are grown either for cash or for feed. Irrigated crops are

grown along many of the major streams. These crops primarily

include corn, alfalfa, forage crops, and sugar beets.

The major soil resource concerns in this region are

overgrazing and the wind erosion and water erosion that occur

where the ground cover has deteriorated. The invasion of

undesirable plant species is a concern on rangeland. Wind

erosion, water erosion, maintenance of the content of organic

matter in the soils, and soil moisture management are major

resource concerns on cropland. The quality of surface water

also is a concern. Sediment, nutrients, pesticides, and organic

material are the major nonpoint sources of surface- and groundwater pollution. Control of saline seeps on rangeland and salt

management on irrigated land are needed in some areas. 
of the United States 157

Figure 58A-1: Location of MLRA 58A in Land Resource Region G.

58A—Northern Rolling High Plains,

Northern Part

This area (shown in fig. 58A-1) is in Montana (99 percent)

and Wyoming (1 percent). It makes up about 42,350 square

miles (109,740 square kilometers). From east to west, the cities

of Glendive, Miles City, and Billings, Montana, are along

Interstate 94 in this MLRA. Interstate 94 ends near Billings, at

the junction with Interstate 90. This area has numerous

national wildlife refuges, including the Charles M. Russell, U.L.

Bend, Hailstone, Lake Mason, and Halfbreed Lake National

Wildlife Refuges. The Custer National Forest and the Crow and

Northern Cheyenne Indian Reservations are in the area.

Physiography

This area is in the Missouri Plateau, Unglaciated, Section of

the Great Plains Province of the Interior Plains. It is an area of

old plateaus and terraces that have been eroded. Slopes

generally are gently rolling to steep, and wide belts of steeply

sloping badlands border a few of the larger river valleys. Local

relief is mainly 10 to 100 feet (3 to 30 meters). In some areas

flat-topped, steep-sided buttes rise sharply above the general

level of the plains. Elevation generally ranges from 2,950 to

3,280 feet (900 to 1,000 meters), increasing from east to west

and from north to south. In a few mountains, it is as high as

6,900 feet (2,105 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Missouri-Musselshell (1004), 35 percent; Lower Yellowstone

(1010), 27 percent; Powder-Tongue (1009), 15 percent; Upper

Yellowstone (1007), 11 percent; Bighorn (1008), 6 percent;

Missouri-Poplar (1006), 4 percent; and Missouri-Little

Missouri (1011), 2 percent. The Missouri and Yellowstone

Rivers run through this area. There are no dams for more than

800 miles along the Yellowstone River, one of the longest freeflowing rivers in the United States. Fort Peck Dam was built in

1937 and was the first dam on the Missouri River. Ft. Peck Lake

also occurs in this MLRA.

Geology

Tertiary continental shale, siltstone, and sandstone underlie

the eastern one-third to one-half of this area. These stream

deposits are part of the Fort Union Formation. This formation

also contains coalbeds. Marine and continental sediments of

the Cretaceous Montana Group underlie the rest of the MLRA,

generally at the higher elevations. The Montana Group

includes the Bearpaw shale; the Judith River sandstone,

siltstone, and shale; the Claggett shale; the Eagle sandstone;

and the Telegraph Creek sandy shale. A group of younger

Cretaceous sediments occurs between the higher elevation

Montana Group sediments and the lower elevation Tertiary

sediments. These younger deposits include the Hell Creek

sandstone and shale, the St. Mary River mudstone, and the

volcaniclastics of the Livingston Group.

Climate

The average annual precipitation is 8 to 22 inches (205 to

560 millimeters) in most of this area but is as much as 30 inches

(760 millimeters) in the mountains. It fluctuates widely from

year to year. Most of the rainfall occurs as frontal storms early

in the growing season, in May and June. Some high-intensity,

convective thunderstorms occur in July and August, and some

rain falls in autumn. Precipitation in winter occurs as snow. The

average annual temperature is 41 to 49 degrees F (5 to 10

degrees C). The freeze-free period averages 155 days and ranges

from 115 to 190 days, decreasing in length with elevation.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:
158 Major Land Resource Areas

Public supply—surface water, 0.7%; ground water, 0.6%

Livestock—surface water, 0.6%; ground water, 0.3%

Irrigation—surface water, 94.4%; ground water, 1.4%

Other—surface water, 1.3%; ground water, 0.8%

The total withdrawals average 2,865 million gallons per day

(10,845 million liters per day). About 3 percent is from ground

water sources, and 97 percent is from surface water sources. The

surface water generally is suitable for all uses, but adequate

supplies away from the Missouri and Yellowstone Rivers are

scarce. The low and erratic precipitation is the principal source

of water for agriculture. Water for livestock is stored in small

reservoirs, but supplies are inadequate for significant irrigation.

Irrigation water in quantity is available from the Missouri and

Yellowstone Rivers and one or two of the larger tributaries of

these rivers.

Ground water is scarce in most of this area, but local sand

and gravel deposits and coalbeds in the Cenozoic Fort Union

Formation yield small to moderate amounts. Small amounts of

ground water are available in the alluvial and terrace deposits

along the Missouri and Yellowstone Rivers. The ground water

is a sodium bicarbonate or sulfate type and generally is hard or

very hard. The level of total dissolved solids, typically more

than 1,000 parts per million (milligrams per liter), generally

exceeds standards for drinking water.

Saline seeps are a problem in the areas of cropland in this

MLRA. Management practices promote infiltration of

precipitation into shallow aquifers. As the shallow water table

rises to the ground surface, evaporation of the water leaves

concentrations of salts behind. The level of total dissolved

solids in the water from saline seeps commonly is more than

4,000 parts per million (milligrams per liter).

Soils

The dominant soil orders in this MLRA are Entisols and

Inceptisols. The soils in the area dominantly have a frigid soil

temperature regime, an ustic soil moisture regime, and mixed or

smectitic mineralogy. They generally are shallow to very deep,

well drained, and clayey or loamy. Ustorthents formed in

residuum on hills and ridges (Bainville, Cabba, Cabbart,

Neldore, and Yawdim series) and in alluvium on fans and terraces

(Lambert series). Ustifluvents (Havre series) formed in alluvium

on fans, terraces, and flood plains. Haplustepts (Busby, Cherry,

Delpoint, Lonna, and Yamacall series) formed in alluvium,

eolian deposits, and residuum on terraces, fans, and hills.

Calciustepts (Cambeth series) formed in alluvium, colluvium,

and residuum on fans, hills, and plains. Natrustalfs (Gerdrum

series) and Haplustolls (Shambo series) formed in alluvium and

glaciofluvial deposits on fans and terraces and in drainageways.

Biological Resources

This area supports grassland vegetation. Western wheatgrass,

bluebunch wheatgrass, green needlegrass, and needleandthread

are the dominant species. In the eastern part of the area, little

bluestem replaces bluebunch wheatgrass as the dominant

species.

Some of the major wildlife species in this area are mule deer,

white-tailed deer, antelope, coyote, fox, badger, beaver,

raccoon, jackrabbit, cottontail, muskrat, mink, ground squirrel,

pheasant, sharp-tailed grouse, Hungarian partridge, sage grouse,

geese, and ducks.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 15%

Grassland—private, 61%; Federal, 15%

Forest—private, 2%; Federal, 2%

Urban development—private, 1%

Water—private, 2%

Other—private, 2%

More than one-half of this area consists of privately owned

ranches generally dominated by livestock production.

Incidental cash or feed small grains and irrigated cropland are

concentrated along the major streams. Some areas in the

southern part of the area consist of forestland in Tribal, national

forest, or private holdings. More than three-fourths of the area

supports native grasses, shrubs, and limited timber and is

grazed by cattle and sheep. The rest is used mainly for dryfarmed wheat. Sugar beets, alfalfa and other hay crops, and

corn for silage are important crops on the irrigated land. Some

of the land is used as tame pasture. Open woodland is on the

upper slopes and the tops of some of the higher buttes and

mountains.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and

productivity of the soils, management of soil moisture, and the

control of saline seeps. Water resource concerns are inefficient

water use on irrigated cropland and excessive amounts of

pesticides, nutrients, and organic material in surface and

ground waters. Plant resource concerns are deterioration of

plant condition, productivity, health, and vigor; noxious and

invasive plants; and the hazard of wildfires. Animal resource

concerns are inadequate food, cover, and shelter.

Conservation practices on cropland generally include crop

residue management (especially minimum tillage), cover crops,

stripcropping, nutrient management, soil salinity management,

and pest management. Practices that improve water use and

distribution on irrigated cropland are irrigation water

management, irrigation water delivery systems, and on-farm

irrigation practices, such as land leveling, land smoothing,

water-control structures, and sprinklers. Noxious and invasive

plants can be controlled by pest management and prescribed

grazing. Forest stand improvement and firebreaks reduce the

hazard of wildfires and improve forest growth, quality, health,

and productivity.
of the United States 159

The most important conservation practices on rangeland

generally include prescribed grazing, fencing, and water

developments. The establishment of food plots and range

improvement practices benefit wildlife. The establishment of

early and late season pastures supplements forage production

and keeps livestock off the rangeland during critical growth

periods. 

Figure 58B-1: Location of MLRA 58B in Land Resource Region G.

58B—Northern Rolling High Plains,

Southern Part

This area (shown fig. 58B-1) is in Wyoming (95 percent) and

Montana (5 percent). It makes up about 19,265 square miles

(49,915 square kilometers). The cities of Sheridan, Gillette, and

Casper, Wyoming, are in this MLRA. Interstate 90 crosses the

northern third of this area from east to west, and Interstate 25

crosses the western third from north to south. The Naval

Petroleum Reserve Military Reservation and the Thunder Basin

National Grasslands are in this area. Most of the Powder River

Basin is in this area. This basin contains important coal, oil,

and gas deposits.

Physiography

This area is in the Missouri Plateau, Unglaciated, Section of

the Great Plains Province of the Interior Plains. It is an area of

old plateaus and terraces that have been deeply eroded.

Elevation generally ranges from 2,950 to 5,900 feet (900 to

1,800 meters), increasing gradually from north to south. On a

few buttes, it is as high as 6,890 feet (2,100 meters). Typically,

local relief is about 150 to 250 feet (45 to 75 meters). Slopes

generally are gently rolling to steep, and wide belts of steeply

sloping badlands border a few of the larger river valleys.

Terraces are common along most of the major river systems in

the area. In places flat-topped, steep-sided buttes rise sharply

above the general level of the plains.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Powder-Tongue (1009), 49 percent; Cheyenne (1012), 34

percent; North Platte (1018), 16 percent; and Missouri-Little

Missouri (1011), 1 percent. The North Platte River runs through

the southern part of this MLRA. The upper reaches of the

Powder, Tongue, Belle Fourche, and Cheyenne Rivers drain the

northern half of the area.

Geology

The middle third of this area is underlain by Tertiary

continental sediments consisting of shale, siltstone, and

sandstone. Cretaceous marine and continental sediments

underlie the northwestern third and southeastern third of the

area. These older units consist of interbedded layers of shale,

siltstone, and sandstone. This MLRA is an important mining

(coal and uranium) and petroleum district. The largest deposits

of coal in the United States occur in this area.

Climate

The average annual precipitation is 9 to 27 inches (230 to

685 millimeters) in most of this area. It fluctuates widely from

year to year. The higher precipitation occurs at the higher

elevations. Most of the rainfall occurs as frontal storms early in

the growing season, in May and June. Some high-intensity,

convective thunderstorms occur in July and August, and some

rain falls in autumn. Precipitation in winter occurs as snow. The

average annual temperature is 41 to 48 degrees F (5 to 9

degrees C). The freeze-free period averages 145 days and ranges

from 115 to 170 days.
160 Major Land Resource Areas

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 3.1%; ground water, 2.5%

Livestock—surface water, 0.4%; ground water, 0.2%

Irrigation—surface water, 83.8%; ground water, 1.4%

Other—surface water, 6.9%; ground water, 1.7%

The total withdrawals average 715 million gallons per day

(2,705 million liters per day). About 6 percent is from ground

water sources, and 94 percent is from surface water sources. The

surface water generally is suitable for all uses, but adequate

supplies away from the North Platte, Powder, and Tongue

Rivers are scarce. The low and erratic precipitation is the

principal source of water for agriculture. Water for livestock is

stored in small reservoirs, but supplies are inadequate for

significant irrigation. Narrow strips of land along the perennial

streams are irrigated with water from the North Platte, Powder,

and Tongue Rivers and some of the larger tributaries of these

rivers.

The Structural Basin aquifer underlies almost all of this area.

This is the most extensively used aquifer in Wyoming. It

consists of lenticular beds of sandstone, coal, and shale. The

ground water is confined, so flowing wells are common.

Because the median concentration of total dissolved solids is

1,100 parts per million (milligrams per liter), this water is

unsuitable for drinking, but it is used for some irrigation and for

livestock. The ground water is a sodium bicarbonate or sulfate

type and is soft or moderately hard.

Small amounts of ground water are available in the alluvial

and terrace deposits along the North Platte, Powder, and Tongue

Rivers. This water is a sodium bicarbonate or sulfate type and is

generally hard or very hard. The level of total dissolved solids

typically exceeds drinking water standards. The ground water

in Wyoming has naturally high levels of flouride, iron,

manganese, selenium, and radionuclides.

Soils

The dominant soil orders in this MLRA are Aridisols and

Entisols. The soils in the area dominantly have a mesic soil

temperature regime, an aridic soil moisture regime that borders

on ustic, and mixed or smectitic mineralogy. They are shallow

to very deep, generally well drained, and loamy or clayey.

Haplargids formed in alluvium (Cambria, Forkwood, and Ulm

series) and in mixtures of alluvium, eolian sediments, and

residuum (Bowbac, Cushman, and Hiland series). Torriorthents

formed in alluvium on alluvial fan remnants, fan piedmonts,

stream terraces, hills, and plateaus (Kishona series) and in

residuum or colluvium on hills (Samday, Shingle, Tassel, and

Theedle series). Mollisols and Alfisols occur in areas that have

an ustic soil moisture regime that borders on aridic.

Biological Resources

This area supports grassland vegetation. Rhizomatous

wheatgrasses, green needlegrass, needleandthread, and blue

grama are the dominant species on deep soils. Rhizomatous

wheatgrasses, bluebunch wheatgrass, Indian ricegrass, and

needleandthread are the major species on shallow soils on hills

and ridges. Basin wildrye, green needlegrass, rhizomatous

wheatgrasses, and shrubs are dominant along bottom land and

streams. Big sagebrush is the dominant shrub.

Some of the major wildlife species in this area are elk, deer,

antelope, coyote, beaver, muskrat, jackrabbit, cottontail rabbit,

sage grouse, and turkey. The species of fish in the area include

rainbow trout, brown trout, brook trout, and cutthroat trout.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 4%

Grassland—private, 76%; Federal, 16%

Forest—private, 1%

Urban development—private, 1%

Other—private, 2%

More than 90 percent of this area supports native grasses and

shrubs grazed by cattle and sheep. About 4 percent is dryfarmed in a wheat-summer fallow rotation. The dry-farmed areas

occur mainly on gently sloping, deep soils. Narrow strips of

land along the Tongue, Powder, and Platte Rivers and some of

their tributaries are irrigated. Alfalfa, other hay crops, and feed

grains are the principal crops. Some tracts are used as tame

pasture. Open stands of ponderosa pine are on the higher

buttes and steep slopes that receive higher amounts of

precipitation.

The major resource concerns are the quantity and quality of

water and soil quality. Conservation practices on rangeland

generally include prescribed grazing, fencing, and water

developments. The establishment of food plots and range

improvement practices benefit wildlife. The establishment of

early and late season pastures supplements forage production

and keeps livestock off the rangeland during critical growth

periods. Conservation practices on cropland generally include

those that minimize wind erosion and maximize the amount of

soil moisture available for crops. 
of the United States 161

Figure 58C-1: Location of MLRA 58C in Land Resource Region G.

58C—Northern Rolling High Plains,

Northeastern Part

This area (shown in fig. 58C-1) is in North Dakota (96

percent) and Montana (4 percent). It makes up about 2,320

square miles (6,015 square kilometers). It has no major cities.

Interstate 94 extends in an east-west direction through the area

near the south unit of Theodore Roosevelt National Park. Parts

of the Fort Berthold Indian Reservation and the Little Missouri

National Grasslands are in this area.

Physiography

Most of this area is in the Missouri Plateau, Unglaciated,

Section of the Great Plains Province of the Interior Plains. The

northeastern part is in the Missouri Plateau, Glaciated, Section

of the same province and division. It has some glacially

modified topography, but it is very similar to the unglaciated

parts. This MLRA is known as the Little Missouri Badlands,

which were formed when the Little Missouri River was diverted

along a steeper course by Pleistocene glaciers. The MLRA is an

area of old plateaus and terraces that have been cut by the Little

Missouri River and its tributaries. Much of the area consists of

rolling hills with some badlands. Moderately steep and steep

slopes occur along the Little Missouri River and its tributaries.

Some isolated mountains, such as the Killdeer Mountains, are

in the area. Elevation is generally about 1,970 to 3,280 feet

(600 to 1,000 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Missouri-Little Missouri (1011), 99 percent, and Lower

Yellowstone (1010), 1 percent. The Little Missouri River flows

through the entire length of this MLRA. It empties into Lake

Sakakawea, formed by Garrison Dam on the Missouri River, in

the northeast corner of the area.

Geology

Tertiary marine sediments, shale, siltstone, and sandstone

occur in most of this area. The White River Group probably

represents isolated remnants of the old plateau surface at the

higher elevations. The Sentinel Butte Formation occurs in most

of the eastern half of this area, and successively older sediments

occur to the west (Bullion Creek Formation) and south (Slope

and Ludlow Formations) at the lower elevations. The

Cretaceous Hell Creek Formation may be exposed in the

southern tip of this area, along the Little Missouri River. The

northeastern part of the area, at the lower end of the Little

Missouri River, has a glacially modified topography. Thin

layers of glacial drift cover the marine sediments in this area.

Deposits of river sand and gravel occur on the valley floors of

the larger streams and on the valley floor and terraces along the

Little Missouri River.

Climate

The average annual precipitation in this area is 14 to 17

inches (355 to 430 millimeters). Most of the rainfall occurs as

frontal storms early in the growing season, in May and June.

Some high-intensity, convective thunderstorms occur in July

and August, and some rain falls in autumn. More than half of

the precipitation falls during the growing season. Precipitation

in winter occurs as snow. The average annual temperature is 41

to 44 degrees F (5 to 7 degrees C). The freeze-free period

averages 145 days and ranges from 130 to 160 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 12.0%; ground water, 8.1%

Irrigation—surface water, 29.5%; ground water, 29.5%

Other—surface water, 9.8%; ground water, 11.2%
162 Major Land Resource Areas

58D—Northern Rolling High Plains,

Eastern Part

This area (shown in fig. 58D-1) is in South Dakota (65

percent), Montana (21 percent), and North Dakota (14 percent).

It makes up about 2,755 square miles (7,145 square kilometers).

It has no major cities. U.S. Highway 85 traverses this area from

north to south. The Little Missouri National Grasslands and

Custer National Forest occur in this area.

Physiography

This area is in the Missouri Plateau, Unglaciated, Section of

the Great Plains Province of the Interior Plains. Elevation

ranges from 2,300 to 4,000 feet (700 to 1,220 meters),

increasing gradually from east to west. Harding Peak, the

highest point in the MLRA, reaches an elevation of 4,019 feet

(1,225 meters). Slopes generally are gently rolling to steep.

The total withdrawals average 1 million gallons per day

(3.8 million liters per day). About 49 percent is from ground

water sources, and 51 percent is from surface water sources.

Most of the surface water is used in the generation of electric

power as Lake Sakakawea drains through Garrison Dam. In

most years, the supply of moisture is inadequate for maximum

crop production. The Little Missouri River and Lake

Sakakawea are the principal sources of surface water in the area.

This water is of good quality and is used for what little

irrigation occurs in the area on the flood plains and terraces

along the Little Missouri River. Some livestock water is stored

in ponds.

Farms and ranches obtain their drinking water and some of

their livestock water from the Fort Union aquifer. The water in

this aquifer is soft, but a high level of total dissolved solids and

salinity limit use of the water for irrigation. The water also

contains naturally high levels of selenium. Ground water is

scarce or does not occur in areas underlain by shale.

Soils

The dominant soil orders in this MLRA are Entisols,

Inceptisols, and Mollisols. The soils in the area dominantly

have a frigid soil temperature regime, an ustic soil moisture

regime that borders on aridic, and mixed mineralogy. They are

shallow to very deep, generally well drained, and loamy.

Ustorthents formed in residuum on hills and plains (Cabbart

series) and in alluvium on alluvial fans and in swales (Patent

series). Ustifluvents (Havre series) and Haplustolls (Kremlin

series) formed in alluvium on flood plains, stream terraces, and

alluvial fans. Ustipsamments (Fleak series) formed in residuum

on hills. Haplustepts formed in colluvium on uplands (Arikara

series) and in alluvium on alluvial fans, stream terraces, and

flood plains (Lonna series).

Biological Resources

This area supports natural prairie vegetation characterized

by western wheatgrass, needleandthread, green needlegrass,

blue grama, and threadleaf sedge. Little bluestem and sideoats

grama are important species on sloping, shallow soils. Big

bluestem and sideoats grama, along with scattered green ash,

chokecherry, and western snowberry, are important species in

swales. North-facing slopes support Rocky Mountain juniper,

green ash, and chokecherry and an understory of little

bluestem, porcupinegrass, and needleandthread.

Some of the major wildlife species in this area are mule deer,

white-tailed deer, antelope, coyote, prairie dog, jackrabbit,

reptiles, amphibians, sharp-tailed grouse, hawks, turkeys, and

grassland birds of various species.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 5%

Grassland—private, 37%; Federal, 42%

Forest—private, 1%; Federal, 2%

Water—private, 2%

Other—private, 11%

The “other” category includes large areas of barren badland.

Grazing and recreation are the dominant land uses. About fourfifths of the area is rangeland that is used for ranching. The

principal livestock enterprise consists of cow-calf operations.

The principal dry-farmed crops are small grains, such as wheat,

barley, and oats. Alfalfa, flax, forage crops, and corn for silage

are grown on irrigated land along the major streams.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and

productivity of the soils, and conservation of soil moisture.

Conservation practices on rangeland generally include

prescribed grazing, fencing, and water developments. The

establishment of food plots and range improvement practices

benefit wildlife. The establishment of early and late season

pastures supplements forage production and keeps livestock off

the rangeland during critical growth periods. Conservation

practices on cropland generally include crop residue

management; conservation tillage systems, such as no-till;

conservation cropping systems that eliminate the need for

fallowing; nutrient management; and pest management. 
of the United States 163

Figure 58D-1: Location of MLRA 58D in Land Resource Region G.

Tongue River Formations, the Oligocene White River Group,

and the Miocene Arikaree Group. These resistant Paleocene,

Oligocene, and Miocene beds stand above the Cretaceous beds.

Ponderosa pine growing on these Tertiary beds further

distinguishes them from the other formations in the MLRA.

Quaternary river sand and gravel deposits occur on the valley

floors and on the terraces along the larger rivers in the area. A

large Quaternary eolian deposit occurs directly south of the

town of Buffalo.

Climate

The average annual precipitation is 14 to 17 inches (355 to

430 millimeters) in most of this area. It fluctuates widely from

year to year. Most of the rainfall occurs as frontal storms early

in the growing season, in May and June. Some high-intensity,

convective thunderstorms occur in July and August.

Precipitation in winter occurs as snow. The average annual

temperature is 42 to 45 degrees F (6 to 7 degrees C). The freezefree period averages 140 days and ranges from 130 to 150 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 3.4%; ground water, 2.4%

Irrigation—surface water, 59.1%; ground water, 21.1%

Other—surface water, 8.7%; ground water, 5.3%

The total withdrawals average 2.5 million gallons per day

(9.5 million liters per day). About 29 percent is from ground

water sources, and 71 percent is from surface water sources. The

low and erratic precipitation is the principal source of water for

agriculture. Most of the surface water in this MLRA is of good

quality and is used for limited irrigation on the flood plains and

terraces along the major streams. Water for livestock is stored in

small ponds or dugouts.

Some wells in the Fort Union-Fox Hills-Hell Creek aquifer

provide water for domestic use and livestock. High levels of

total dissolved solids and salinity limit the use of this ground

water for irrigation. Naturally high levels of selenium and

molybdenum occur in the water from the Fort Union sediments.

These elements can cause health problems in livestock.

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, Inceptisols, and Mollisols. The soils in the area

dominantly have a frigid soil temperature regime, an ustic soil

moisture regime that borders on aridic, and mixed mineralogy.

They are shallow to very deep, generally well drained, and

loamy or clayey. Natrustalfs formed in residuum on hills and

ridges (Bullock and Parchin series) and in alluvium or fluvial

Local relief is mainly 80 to 330 feet (25 to 100 meters). In

places flat-topped, steep-sided buttes rise sharply above the

general level of the plains.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Missouri-Little Missouri (1011), 52 percent; Missouri-Oahe

(1013), 46 percent; and Lower Yellowstone (1010), 2 percent.

The Little Missouri River and the headwaters of the major

tributaries that eventually form the Grand and Moreau Rivers in

South Dakota are in this area.

Geology

Cretaceous marine and continental sediments of shale,

siltstone, and sandstone occur in the majority of this MLRA.

The continental and marine Hell Creek Formation occurs in

approximately 85 percent of the MLRA, and the Fox Hills

Sandstone forms the southern boundary of the MLRA. Tertiary

deposits also occur in scattered areas throughout the MLRA.

These deposits are made up of the Paleocene Ludlow and
164 Major Land Resource Areas

60A—Pierre Shale Plains

This area (shown in fig. 60A-1) is in South Dakota (70

percent), Wyoming (20 percent), Nebraska (8 percent), and

Montana (2 percent). It makes up about 10,150 square miles

(26,295 square kilometers). It encircles the Black Hills and the

Dakota Hogback. The eastern half of Rapid City and the town

of Belle Fourche, South Dakota, are in this area. Interstate 90

bisects part of the area as it parallels the northern border of the

Badlands National Park, near Cactus Flat, and enters Rapid

City on the east. It then skirts the Black Hills as it leaves South

Dakota and enters Wyoming in the northwest part of the area.

This MLRA includes the Oglala National Grasslands and parts

of the Thunder Basin and Buffalo Gap National Grasslands.

Small parts of the Pine Ridge Indian Reservation, the Badlands

National Park, and the Black Hills National Forest occur in this

MLRA. Ellsworth Air Force Base is just outside Rapid City.

Physiography

This area is in the Missouri Plateau, Unglaciated, Section of

the Great Plains Province of the Interior Plains. It is an area of

old plateaus and terraces that have been deeply eroded.

Elevation is generally 2,620 to 3,610 feet (800 to 1,100 meters)

on uplands, but it ranges to 4,260 feet (1,300 meters). The shale

plains have long, smooth slopes and generally are gently

sloping to strongly sloping. Slopes are moderately steep or

steep along drainages and streams. Extensive terraces occur

along many of the major streams draining the Black Hills.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

deposits on fans, terraces, and till plains (Absher and Gerdrum

series). Ustorthents (Cabbart and Delridge series) and

Torriorthents (Blackhall series) formed in residuum on hills and

plains. Haplustepts (Twilight series) formed in alluvium or

eolian sediments over residuum on hills and ridges. Argiustolls

formed in alluvium or fluvial deposits (Assinniboine series) or

mixed alluvium and colluvium (Eapa series) on fans, terraces,

and till plains and in residuum on hills and ridges (Marmarth

series). Haplustolls formed in residuum on hills and ridges

(Rhame series).

Biological Resources

The native vegetation in this area consists primarily of

grasses and forbs. Some trees and shrubs are along streams. The

area supports mixed prairie vegetation characterized by western

wheatgrass, green needlegrass, blue grama, and buffalograss.

Threadleaf sedge, buffalograss, blue grama, and some little

bluestem grow on shallow soils. Needleandthread and prairie

sandreed grow on sandy soils. Big bluestem grows along

streams, especially where the soil has an effective water table.

The most common forbs are purple coneflower, prairie coneflower,

American vetch, dotted gayfeather, Missouri goldenrod, breadroot

scurfpea, silverleaf scurfpea, scarlet globemallow, heath aster,

desert biscuitroot, and cudweed sagewort.

Shrubs, such as buffaloberry, silver sagebrush, western

snowberry, and chokecherry, are common. Big sagebrush grows

in the driest areas of the western part of the MLRA. Boxelder,

green ash, and plains cottonwood are the principal trees along

streams and drainageways. Ponderosa pine forests occur on the

upper slopes and on the top of some of the higher buttes in

Custer National Forest. These forests stand out from the normal

native grass vegetation in the northwestern part of the MLRA.

Silver sagebrush and big sagebrush grow on clayey soils in the

western part of the MLRA.

Some of the major wildlife species in this area are mule deer,

white-tailed deer, antelope, coyote, fox, bobcat, rattlesnake,

badger, raccoon, porcupine, beaver, skunk, mink, jackrabbit,

prairie dog, golden eagle, ferruginous hawks, pheasant, sharptailed grouse, sage grouse, gray partridge, magpie, and lark

bunting.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 12%

Grassland—private, 81%; Federal, 3%

Urban development—private, 1%

Water—private, 1%

Other—private, 2%

More than four-fifths of this area is in private ranches. The

dominant land uses are rangeland and hayland. Less than 5

percent of the area is federally owned. Most of the area supports

native grasses and shrubs grazed by cattle and sheep. Gently

sloping, deep and moderately deep soils, making up 10 to 15

percent of the area, are used for dry-farmed wheat or alfalfa.

Some tracts are used as tame pasture. Open woodland is on the

upper slopes and the top of some of the higher buttes.

The major soil resource concerns are wind erosion and soil

quality on cropland, especially where wheat-fallow is the

principal crop rotation. Surface water quality also is a resource

concern. Wind erosion and soil quality are resource concerns on

continuously overgrazed rangeland.

The most important conservation practices on rangeland are

prescribed grazing, fencing, and water developments. The

establishment of food plots and range improvement practices

benefit wildlife. The establishment of early and late season

pastures supplements forage production and keeps livestock off

the rangeland during critical growth periods. The conservation

practices that are important on cropland are no-till and other

conservation tillage systems, contour farming, and crop residue

management. 
of the United States 165

Climate

The average annual precipitation in this area is 13 to 22

inches (330 to 560 millimeters). Most of the rainfall occurs as

frontal storms early in the growing season, in May and June.

Some high-intensity, convective thunderstorms occur in July

and August. Precipitation in winter occurs mainly as snow that

usually is accompanied by high winds that cause much drifting.

The average annual temperature is 43 to 49 degrees F (6 to 9

degrees C). The freeze-free period averages about 150 days and

ranges from 130 to 170 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.9%; ground water, 5.4%

Livestock—surface water, 4.2%; ground water, 0.3%

Irrigation—surface water, 76.1%; ground water, 4.5%

Other—surface water, 7.5%; ground water, 1.2%

The total withdrawals average 110 million gallons per day

(415 million liters per day). About 11 percent is from ground

water sources, and 89 percent is from surface water sources.

Because of the limited amount of precipitation, the production

of dry-farmed crops is marginal. Most of the soils are moist or

wet early in spring and are deficient in moisture during much of

the growing season. In irrigated areas along the Belle Fourche

River in the northern part of the area and the Cheyenne River in

the southern part, surface water is drawn from the Belle Fourche

and Angostura Reservoirs, respectively. Some areas along

Rapid Creek are irrigated. Water for livestock comes mainly

from runoff that flows into dams. Surface runoff from the

forested Black Hills is of good quality. Stream runoff seeps into

the cavernous Pahasapa limestone within the Black Hills.

Springs occur at the edges of the Black Hills when this water

discharges at the surface. This water is of excellent quality and

is used for public supply.

Pierre Shale underlies almost all of this area, so ground water

is scarce. A few areas have shallow water wells for domestic use,

but the water is of marginal quality for drinking. Some shallow

wells also draw domestic water from alluvial sand and gravel

under the larger stream valleys. This water is of much better

quality than the shallow ground water in the Pierre Shale.

Soils

The dominant soil orders in this MLRA are Entisols,

Alfisols, Vertisols, and Inceptisols. Mollisols are of lesser

extent. The soils in the area dominantly have a mesic soil

temperature regime, an ustic soil moisture regime, and smectitic

or mixed mineralogy. They are shallow to very deep, generally

Figure 60A-1: Location of MLRA 60A in Land Resource Region G.

Cheyenne (1012), 82 percent; Missouri-White (1014), 9

percent; Missouri-Oahe (1013), 5 percent; and Missouri-Little

Missouri (1011), 4 percent. The Cheyenne and Belle Fourche

Rivers occur in this MLRA.

Geology

Cretaceous Pierre Shale underlies almost all of this area. This

is a marine sediment having layers of volcanic ash that has

been altered to smectitic clay. This clay shrinks as it dries and

swells as it gets wet, causing significant problems for road and

structural foundations. Cretaceous shale of the Belle Fourche,

Mowry, and Skull Creek Formations is adjacent to the Dakota

Hogback. These formations, along with Newcastle Sandstone,

make up what is called the Graneros Group. Tertiary river

gravel, deposited by streams carrying erosional debris from the

Black Hills following their uplift, caps the ridges separating the

streams draining the Black Hills.
166 Major Land Resource Areas

60B—Pierre Shale Plains, Northern Part

This area (shown in fig. 60B-1) is almost entirely in

Montana (94 percent) and Wyoming (6 percent). A very small

part of the area is in North Dakota. The area makes up about

3,375 square miles (8,750 square kilometers). It occurs in the

uplands between most of the major rivers in southeastern

Montana and northeastern Wyoming. It has no major cities. U.S.

Highway 212 cuts across the southern end of the area. The

Custer National Forest occurs in this area.

Physiography

This area is in the Missouri Plateau, Unglaciated, Section of

the Great Plains Province of the Interior Plains. It is an area of

old plateaus and terraces that have been deeply eroded.

Elevation ranges from 2,950 to 3,300 feet (900 to 1,005 meters)

on uplands. The shale plains have long, smooth, gentle to

strong slopes. Slopes along drainageways and streams are

moderately steep or steep.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Missouri-Little Missouri (1011), 53 percent; Powder-Tongue

(1009), 27 percent; and Lower Yellowstone (1010), 20 percent.

The MLRA has no major rivers.

Geology

Marine and continental sediments of the Cretaceous

Montana Group underlie most of this MLRA, generally at the

well drained, and clayey. Paleustalfs (Jaywest series) formed in

alluvium on alluvial fans. Haplustalfs (Leiter series) formed in

alluvium and residuum on hills, alluvial fans, and fan remnants.

Ustorthents (Fairburn, Grummit, Lismas, and Samsil series) and

Haplusterts (Pierre, Kyle, and Swanboy series) formed in

residuum and local alluvium on plains and hills. Haplustepts

formed in residuum and alluvium on stream terraces and

uplands (Bufton series) and in alluvium and residuum on hills,

alluvial fans, and fan remnants (Echeta and Cromack series).

Argiustolls (Nunn and Satanta series) are on old alluvial

terraces along many of the streams that drained the Black Hills.

Biological Resources

The native vegetation in this MLRA consists primarily of

grasses and forbs. Some trees and shrubs occur along streams.

This area supports mixed natural prairie vegetation

characterized by grasses, such as western wheatgrass, green

needlegrass, blue grama, and buffalograss. Little bluestem,

buffalograss, and sideoats grama grow on the shallow soils. Big

bluestem grows along streams, especially where the soils have

an effective water table. The most common forbs are purple

coneflower, prairie coneflower, American vetch, dotted

gayfeather, Missouri goldenrod, breadroot scurfpea, silverleaf

scurfpea, scarlet globemallow, heath aster, desert biscuitroot,

and cudweed sagewort. Shrubs include sand sagebrush on

sandy soils and silver sagebrush, western snowberry, and

leadplant on clayey soils in the western part of the area. Big

sagebrush grows in the driest part of the MLRA, in

southwestern Fall River County and extending into Wyoming.

Boxelder, green ash, and plains cottonwood are the principal

trees along streams and drainageways. Eastern redcedar occurs

in scattered areas throughout the uplands, especially along the

Cheyenne River. Bur oak and ponderosa pine commonly occur

in areas of the acid shale of the Graneros Group.

Some of the major wildlife species in this area are mule deer,

white-tailed deer, antelope, coyote, bobcat, badger, beaver,

raccoon, skunk, muskrat, mink, jackrabbit, cottontail, prairie

dog, turkey, pheasant, sharp-tailed grouse, Hungarian partridge,

sage grouse, mourning dove, mallard, long-billed curlew,

killdeer, yellow-headed blackbird, and red-winged blackbird.

The species of fish in the area include walleye, channel catfish,

white bass, largemouth black bass, bluegill, and northern pike.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 11%

Grassland—private, 59%; Federal, 23%

Forest—private, 1%

Urban development—private, 1%

Water—private, 1%

Other—private, 4%

The dominant land uses are rangeland and hayland.

Practically all of this area is in farms and ranches. Most of it

supports native grasses and is grazed by livestock.

Approximately 10 percent of the area is used for small grain

grown for grain and livestock feed. Some small areas of nearly

level to moderately sloping soils are used for winter wheat or

feed crops for livestock.

The major resource concerns are wind erosion and surface

water quality. The major soil resource concerns are wind

erosion and soil quality on cropland, especially where wheatfallow is the principal crop rotation. Wind erosion and soil

quality also are concerns on continuously overgrazed

rangeland.

Conservation practices on rangeland generally include

prescribed grazing, fencing, and water developments. The

establishment of food plots and range improvement practices

benefit wildlife. The establishment of early and late season

pastures supplements forage production and keeps livestock off

the rangeland during critical growth periods. Conservation

practices on cropland generally include no-till and other kinds

of conservation tillage, contour farming, and crop residue

management. 
of the United States 167

Figure 60B-1: Location of MLRA 60B in Land Resource Region G.

freeze-free period averages 140 days and ranges from 130 to

155 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 0.3%; ground water, 0.7%

Irrigation—surface water, 62.9%; ground water, 31.4%

Other—surface water, 2.0%; ground water, 2.6%

The total withdrawals average 3 million gallons per day (11

million liters per day). About 35 percent is from ground water

sources, and 65 percent is from surface water sources. Because

of the limited amount of precipitation, the production of dryfarmed crops is marginal. Most of the soils are moist or wet

early in spring and are deficient in moisture during much of the

growing season. The quality of the surface water is good, but

the quantity typically is inadequate. Some limited irrigation

occurs along the larger streams on the edges of this area. Water

for livestock comes mainly from runoff that flows into dams.

Ground water is scarce in most of the area, but local deposits

of sand and gravel in the Fox Hills Sandstone and Hell Creek

Formation yield small to moderate amounts of domestic and

livestock water. This ground water is a sodium bicarbonate or

sulfate type and generally is hard or very hard. The level of

total dissolved solids, typically more than 1,000 parts per

million (milligrams per liter), exceeds the standards for

drinking water. The water from alluvial deposits in areas of

flood plains and terraces is of much better quality than the

water in the bedrock aquifers. Shallow wells provide a limited

amount of water for irrigation, domestic use, and livestock.

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, and Vertisols. The soils in the area dominantly have a

frigid soil temperature regime, an ustic soil moisture regime,

and smectitic mineralogy. They are shallow to very deep,

generally well drained, and clayey. Natrustalfs (Absher and

Gerdrum series) formed in alluvium, glaciofluvial deposits, and

till on alluvial fans, stream terraces, and plains. Haplusterts

formed in alluvium and/or residuum on alluvial fans, stream

terraces, and plains (Bascovy and Bickerdyke series) and in

alluvium and lacustrine deposits on alluvial fans, stream

terraces, and lake plains (Marias and Marvan series).

Ustorthents formed in mixed residuum, alluvium, and

colluvium on hills and plains (Neldore, Orinoco, and Yawdim

series) and in alluvium, lacustrine deposits, and glaciofluvial

deposits on alluvial fans, stream terraces, and plains (Vanda

series).

higher elevations. The Montana Group in this part of Montana

includes Fox Hills Sandstone and Pierre Shale. A group of

younger Cretaceous sediments occurs at the lower elevations at

the north and west ends of the area. These younger deposits

include Hell Creek sandstone and shale, St. Mary River

mudstone, and the volcaniclastics of the Livingston Group. The

older Cretaceous Niobrara shale and chalk beds occur at the

higher elevations in the southeast corner of this MLRA.

Climate

The average annual precipitation in this area is 11 to 15

inches (280 to 380 millimeters). Most of the annual

precipitation occurs as high-intensity, convective

thunderstorms during the growing season. Precipitation in

winter occurs mainly as snow, which usually is accompanied

by high winds that cause much drifting. The average annual

temperature is 43 to 46 degrees F (6 to 8 degrees C). The
168 Major Land Resource Areas

61—Black Hills Foot Slopes

This area (shown in fig. 61-1) is in Wyoming (58 percent)

and South Dakota (42 percent). It makes up about 1,865 square

miles (4,840 square kilometers). The cities of Spearfish, Sturgis,

and Hot Springs, South Dakota, and Sundance and Newcastle,

Wyoming, are in this area. Rapid City, South Dakota, is on the

eastern edge of the MLRA. Wind Cave National Park, Devil’s

Tower National Monument, and parts of the Thunder Basin

National Grasslands and the Black Hills National Forest occur

in this MLRA.

Physiography

This area is in the Black Hills Section of the Great Plains

Province of the Interior Plains. It is an area of steeply dipping

rocks circling the maturely dissected domed mountains of the

Black Hills. As the mountains were uplifted, older sediments

were tipped up, so they dip away from the core of the

mountains. Elevation is mainly 2,950 to 3,940 feet (900 to

Biological Resources

This area supports mixed natural prairie vegetation

characterized by western wheatgrass, green needlegrass, and

blue grama. Little bluestem and sideoats grama grow on

shallow soils. Some areas in the southern part of the MLRA

support pine forests. Oak species grow in some protected draws.

Some of the major wildlife species in this area are mule deer,

white-tailed deer, antelope, coyote, fox, bobcat, rattlesnake,

badger, raccoon, porcupine, beaver, skunk, mink, jackrabbit,

prairie dog, golden eagle, ferruginous hawks, pheasant, sharptailed grouse, sage grouse, gray partridge, magpie, and lark

bunting.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 5%

Grassland—private, 63%; Federal, 29%

Forest—private, 1%; Federal, 1%

Urban development—private, 1%

Practically all of this area is in farms or ranches. Most of it is

rangeland used for grazing by livestock. Some small areas of

nearly level to moderately sloping soils are used for winter

wheat or for livestock feed crops.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and

productivity of the soils, management of soil moisture, and

control of saline seeps. Water resource concerns include failure

to meet plant needs because of inefficient water use on irrigated

cropland. They also include excessive amounts of pesticides,

nutrients, and organic material in surface and ground waters.

Plant resource concerns are deterioration of plant condition,

productivity, health, and vigor; noxious and invasive plants;

and wildfires. Animal resource concerns are inadequate food,

cover, and shelter.

Conservation practices on cropland generally include crop

residue management (especially minimum tillage), cover crops,

stripcropping, nutrient management, soil salinity management,

and pest management. Practices that improve water use and

distribution on irrigated cropland generally include irrigation

water management, irrigation water delivery systems, and onfarm irrigation practices, such as sprinklers. Noxious and

invasive plants can be controlled by pest management and

prescribed grazing. Forest stand improvement and firebreaks

reduce the hazard of wildfires and improve forest growth,

quality, health, and productivity.

Conservation practices on rangeland generally include

prescribed grazing, fencing, and water developments. The

establishment of food plots and range improvement practices

benefit wildlife. The establishment of early and late season

pastures supplements forage production and keeps livestock off

the rangeland during critical growth periods. 

Figure 61-1: Location of MLRA 61 in Land Resource Region G.
of the United States 169

The total withdrawals average 7.5 million gallons per day

(28 million liters per day). About 80 percent is from ground

water sources, and 20 percent is from surface water sources.

Flowing streams, shallow wells, and springs provide almost all

of the domestic and public water. The surface water is of good

quality during high runoff periods. At low flows, however,

much of the surface water does not meet drinking water

standards because of pollution and high levels of total

dissolved solids. Much of the water used in this area is for

public supply for the numerous cities and towns that were built

on the level ground that forms the core of the area. Crop

production in the area is marginal because of the limited

amount of precipitation. Some limited irrigation occurs along

the major streams that headwater in the Black Hills and cross

the area. Most of the soils suitable for cultivation are dry during

much of the growing season. Ground water is scarce because of

the shale under most of the area. Many cities obtain public

supply water from large springs in the Pahasapa limestone on

the inside edge of this area.

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, and Mollisols. The soils in the area dominantly have a

frigid or mesic soil temperature regime, an aridic or ustic soil

moisture regime, and mixed or smectitic mineralogy. They are

shallow to very deep, generally well drained, and loamy.

Haplustalfs (Larkson series) and Hapludalfs (Lakoa series)

formed in residuum on hills and valley walls. Haplustolls

(Tilford series) formed in silty sediments on valley floors.

Argiustolls formed in silty sediments (Boneek and Vale series)

and eolian and alluvial deposits (Satanta and Nunn series) on

stream terraces and uplands. Ustorthents formed in residuum on

uplands (Butche and Spearfish series) and in alluvium and

colluvium on stream terraces and uplands (Nevee and

Gypnevee series). Torriorthents formed in residuum on hills and

foothills (Canyon, Crownest, Gaynor, Shingle, and Tassel

series) and in basins (Enning, Fairburn, and Mittenbutte series).

Biological Resources

This area supports open grassland, forest, and savanna

vegetation. The grassland is characterized by native grasses,

such as little and big bluestem, prairie junegrass, Indian

ricegrass, sand dropseed, green needlegrass, western wheatgrass,

and needleandthread. The most common forbs are white

beartongue, ballhead gilia, white milkwort, dotted gayfeather,

rush skeletonplant, purple coneflower, prairie coneflower, and

trailing fleabane. The most common shrubs are silver

sagebrush, rubber rabbitbrush, and broom snakeweed.

Ponderosa pine grows in scattered stands of open forest. Bur

oak grows throughout the area, and in places it grows in nearly

pure stands. Quaking aspen and eastern hophornbeam are

1,200 meters) but ranges to 5,580 feet (1,700 meters). Slopes

generally are hilly but are nearly level to moderately sloping

where shale red beds occur in the middle of this area. They

are steep along both edges of the area where rocks that are

more erosion resistant occur. The drainage pattern is well

defined.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Cheyenne (1012), 98 percent, and Missouri-Little Missouri

(1011), 2 percent. The Belle Fourche River is the only river

flowing through this MLRA, but many creeks draining the

Black Hills cross the area. The creeks are the headwaters of the

Cheyenne River, one of the major rivers in western South

Dakota.

Geology

This area consists of marine sediments older than the

Cretaceous Pierre Shale on the high plains surrounding this

area. The older rocks were brought closer to the surface during

the uplift that formed the Black Hills. The Lower Cretaceous

Fall River and Lakota (Inyan Kara Group) sandstones occur on

the outside boundary of the area and are referred to as the

Dakota Hogback. Permian limestone and shale of the

Minnekahta limestone form the inside boundary and occur in

the mountains of the Black Hills (MLRA 62). The Triassic red

beds of the Spearfish shale form a low valley, the “red valley,”

surrounding the Black Hills between the two ridges formed by

the Inyan Kara and Minnekahta Formations. Native Americans

called these red beds the “Great Race Track.” The red beds have

gypsum and anhydrous layers. Ground-water seepage can

dissolve these layers, creating sinkholes on the surface.

Climate

The average annual precipitation in this area is 14 to 24

inches (355 to 610 millimeters). Most of the rainfall occurs as

frontal storms early in the growing season, in May and June.

Some high-intensity, convective thunderstorms occur in July

and August. The average snowfall in winter is 24 to 39 inches

(60 to 100 centimeters), increasing with elevation. The average

annual temperature is 40 to 49 degrees F (5 to 9 degrees C). The

freeze-free period averages 140 days and ranges from 115 to

165 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 13.1%; ground water, 78.9%

Livestock—surface water, 1.6%; ground water, 0.3%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 5.3%; ground water, 0.8%
170 Major Land Resource Areas

62—Black Hills

This area (shown in fig. 62-1) is in South Dakota (74 percent)

and Wyoming (26 percent). It makes up about 3,040 square miles

(7,875 square kilometers). The towns of Lead, Deadwood, Hill

City, and Custer, South Dakota, are in this area. U.S. Highways 16

and 385 cross the MLRA. The Black Hills National Forest, Custer

State Park, Mt. Rushmore National Monument, Wind Cave

National Park, and Jewel Cave National Monument are in this

MLRA. A large-scale mountain carving, the privately owned

Crazy Horse Monument, also is in this area. The Black Hills is a

major tourist destination in the United States.

throughout the forested areas. Scattered green ash, boxelder,

and American elm grow along with big bluestem in areas along

stream bottoms.

Some of the major wildlife species in this area are elk, mule

deer, white-tailed deer, antelope, coyote, fox, bobcat, mountain

lion, wild turkey, sage grouse, ruffed grouse, and sharp-tailed

grouse.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 8%

Grassland—private, 54%; Federal, 7%

Forest—private, 19%; Federal, 5%

Urban development—private, 6%

Other—private, 1%

Most of this area is privately owned land in farms and

ranches. The native grasses are used mainly for grazing by

livestock. Some of the less sloping areas are used for alfalfa and

small grain for livestock feed. Ponderosa pine grows in some

areas adjacent to the Black Hills. Urban expansion is a growing

concern.

The major resource concerns in this area are water quality

and urban expansion. The major soil resource concerns are

wind erosion, water erosion, and urban expansion.

Conservation practices on rangeland generally include

prescribed grazing, fencing, and water developments. The

establishment of food plots and range improvement practices

benefit wildlife. Conservation practices on cropland generally

include contour farming, crop rotations that include grasses and

legumes, and crop residue management. The Grassland Reserve

Program is an increasingly important tool that helps to limit

urban expansion. Forest stand improvement and firebreaks

reduce the hazard of wildfires and improve forest growth,

quality, health, and productivity. 

Figure 62-1: Location of MLRA 62 in Land Resource Region G.

Physiography

This area forms the core of the Black Hills Section of the

Great Plains Province of the Interior Plains. It is an area of

maturely dissected domed mountains. Elevation is mainly

3,600 to 6,565 feet (1,100 to 2,000 meters), but it is 7,242 feet

(2,208 meters) on Harney Peak, the highest point in the United

States east of the Rocky Mountains. Slopes range from

moderately sloping on some of the high plateaus to very steep

along drainageways and on peaks and ridges. Narrow valleys

generally are gently sloping to strongly sloping.

The only Hydrologic Unit Area (identified by a four-digit

number) that makes up this MLRA is Cheyenne (1012). Many

streams that drain the MLRA, including Box Elder, Castle,

French, Rapid, Spearfish, and Spring Creeks, are popular

destinations for trout fishermen.
of the United States 171

sources, and 73 percent is from surface water sources. In most

years soil moisture is adequate for normal plant growth.

Precipitation, perennial streams, springs, and shallow wells

provide adequate water for domestic use. The surface water is

plentiful and of good quality. Most public supply water for

towns in the Black Hills comes from streams. Small

hydroelectric plants are on Spearfish Creek.

Most of the granitic and metamorphic rocks in this area are

not principal aquifers. Some of the purest water in South

Dakota, however, comes from springs in the granite rocks

around the Mt. Rushmore National Monument. The

metamorphic rocks have joints and bedding and cleavage

planes that allow for transmission of water at the lower

elevations. These rocks commonly are the source of the

domestic supply in the Black Hills. The water from the

metamorphic rocks is much more mineralized than the water in

the granite. The Pahasapa (Madison) limestone and younger

sandstone and limestone sediments are the primary aquifers in

this MLRA. The ground water is plentiful and is used primarily

for irrigation and livestock. It has high levels of total dissolved

solids and is mostly a sodium sulfate type.

Soils

The dominant soil orders in this MLRA are Alfisols and

Mollisols. The soils in the area dominantly have a frigid or

cryic soil temperature regime, a udic or ustic soil moisture

regime, and mixed, micaceous, or smectitic mineralogy. They

are shallow to very deep, generally well drained, and loamy or

clayey. Hapludalfs (Buska, Citadel, Pactola, Vanocker, and

Virkula series), Haplocryalfs (Stovho and Trebor series), and

Ustorthents (Sawdust series) formed in residuum on mountains.

In some areas the residuum is mixed with alluvium or

colluvium. Haplustalfs (Mocmont series) formed in colluvium

or alluvium on fans, hills, and mountains. Haplustolls formed in

alluvium on fan aprons and piedmonts (Cordeston series) and

in residuum on mesas and hills (Paunsaugunt series). Rock

outcrop is common throughout this area.

Biological Resources

This area supports open to dense forest vegetation.

Ponderosa pine is the dominant species. Black Hills spruce

grows at the higher elevations and along the major

drainageways. Paper birch and quaking aspen are on sites that

have been burned over by wildfire or cleared by logging.

Junegrass, fuzzyspike wildrye, green muhly, prairie dropseed,

roughleaf ricegrass, green needlegrass, poverty oatgrass,

Richardson’s needlegrass, and Canada wildrye are the most

common native grasses under open forest stands. The most

common native forbs and shrubs are spreading dogbane, Indian

hemp, low larkspur, prairie star, Richardson’s alumroot, sulfur

paintbrush, bearberry, common juniper, grouse berry, redosier

dogwood, poison ivy, Saskatoon serviceberry, red raspberry,

Geology

The core of the Black Hills is a plutonic mass of granite with

steeply dipping metamorphic rocks, primarily slate and schist,

directly surrounding it. A plateau of Mississippian limestone

surrounds the igneous and metamorphic rock core. This

Pahasapa (Madison) limestone is broken around the outer edges

of the uplifted area. The Permian Minnekahta limestone forms

the outermost boundary of the area. Many other tilted

sandstone, shale, and limestone units are exposed like a

bathtub ring inside the steeply dipping Pahasapa limestone.

These older units are also exposed on the valley walls along the

major drainages that cut through the rock layers.

There are two unique geologic features in the Black Hills.

One is the loss of water in the creeks that flow across the

cavernous Pahasapa limestone ringing the Black Hills. This

water is discharged to the surface again in major springs that

occur at the margins of the Black Hills. The other feature

involves a series of Tertiary igneous intrusives, aligned east to

west across the northern third of the Black Hills. Gold deposits

formed in the country rock adjacent to these igneous rocks. The

largest gold mine in North America, the Homestake Gold Mine

in Lead, South Dakota, operated for 120 years in this area. The

mine closed in 2001. Scientists across the country are working

on converting some of the mined levels into underground

laboratories for the study of nuclear particles.

Climate

The average annual precipitation in this area is 16 to 37

inches (405 to 940 millimeters), increasing with elevation and

decreasing from west to east and north to south. Most of the

rainfall occurs as frontal storms early in the growing season, in

May and June. Some high-intensity, convective thunderstorms

occur in July and August. Precipitation in winter occurs mostly

as snow. The annual snowfall ranges from about 60 inches (150

centimeters) at the lower elevations to as much as 140 inches

(355 centimeters) at the higher elevations. The average annual

temperature is 36 to 48 degrees F (2 to 9 degrees C). The freezefree period averages 125 days and ranges from 85 to 165 days.

It is shortest at the higher elevations and in the northwestern

part of the area.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 33.1%; ground water, 16.6%

Livestock—surface water, 13.0%; ground water, 2.5%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 26.7%; ground water, 8.0%

The total withdrawals average 2.4 million gallons per day (9

million liters per day). About 27 percent is from ground water
172 Major Land Resource Areas

63A—Northern Rolling Pierre Shale

Plains

This area is primarily in South Dakota, but a very small part

is in North Dakota (fig. 63A-1). The area makes up about

10,160 square miles (26,330 square kilometers). The towns of

Murdo, Philip, Fort Pierre, and Pierre, the capital of South

chokecherry, creeping blackberry, wild spirea, and western red

currant.

Some of the major wildlife species in this area are elk,

mule deer, white-tailed deer, coyote, red fox, gray fox,

bobcat, mountain lion, raccoon, porcupine, skunk, beaver, red

squirrel, northern flying squirrel, mink, bald eagle, golden

eagle, red-tailed hawk, turkey, ruffed grouse, and sharp-tailed

grouse.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 2%

Grassland—private, 22%; Federal, 25%

Forest—private, 19%; Federal, 28%

Urban development—private, 2%

Other—private, 2%

The forestland in this area is used mainly for timber

production, recreation, and grazing. About half of the area is in

the Black Hills National Forest. The Black Hills area, an

important tourist attraction, is used for logging, mining,

recreation, and hunting. Some areas, especially in the northern

part of the Black Hills, are mined for gold and other minerals.

Scattered small farms and ranches, rural homes, and summer

homes on small acreages are throughout the area. Small ranches

and farms depend on the Black Hills National Forest for

summer grazing.

The major resource concerns are the erosion and surface

compaction caused by logging, mining, wildfires, grazing,

and urban expansion. The quality of ground water and surface

water is another concern, especially in the northern part of the

Black Hills, because of contamination from mine waste and

septic systems in areas of rural development and urban

expansion.

The major erosion-control practices are critical area planting

and proper tree harvesting on disturbed or burned sites and

proper grazing management. Conservation practices on

rangeland generally include prescribed grazing, fencing, and

water developments. Forest stand improvement and firebreaks

reduce the hazard of wildfires and improve forest growth,

quality, health, and productivity. 

Figure 63A-1: Location of MLRA 63A in Land Resource Region G.

Dakota, are in this MLRA. Interstate 90 crosses the

southernmost part of this area. The Fort Pierre and Buffalo Gap

National Grasslands are in this MLRA. Several Indian

reservations, including the Cheyenne River, Lower Brule, and

Standing Rock Indian Reservations, are in this area.

Physiography

This area is primarily in the Missouri Plateau, Unglaciated,

Section of the Great Plains Province of the Interior Plains. This

is an area of old plateaus and terraces that have been deeply

eroded. Parts of the eastern edge of this area are in the Missouri

Plateau, Glaciated, Section of the Great Plains Province of the

Interior Plains. Isolated remnants of glacial till are in the

glaciated section. Glacial erratics have been found as far west as

the center of this area. Elevation ranges from 1,300 to 1,640

feet (395 to 500 meters) on the bottom land along the Missouri

River to 1,640 to 2,950 feet (500 to 900 meters) on the shale

plain uplands. The areas that are cropped are mainly at
of the United States 173

elevations of about 1,640 to 2,620 feet (500 to 800 meters).

These areas are nearly level to rolling and have long, smooth

slopes and a well defined dendritic drainage system. River and

creek valleys have smooth floors and steep walls.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Missouri-White (1014), 50 percent; Missouri-Oahe (1013), 34

percent; and Cheyenne (1012), 16 percent. The Missouri River

is mostly inside this area along its east edge. All five of the

major rivers draining western South Dakota cross this area.

From north to south, these are the Grand, Moreau, Cheyenne,

Bad, and White Rivers. With the exception of the White River,

the confluence of all these rivers with the Missouri River occurs

in this area. Three of the four lakes created by main-stem dams

on the Missouri River are in this area—Lake Oahe, Lake

Sharpe, and Lake Francis Case.

Geology

Cretaceous Pierre Shale underlies almost all of this area. This

is a marine sediment having layers of volcanic ash that has

been altered to smectitic clays. These clays shrink as they dry

and swell as they get wet, causing significant problems for road

and structural foundations. Fox Hills Sandstone occurs at the

higher elevations in the northern and western parts of the area.

Tertiary and Quaternary river deposits, remnants of erosion from

the Black Hills following their uplift, cap isolated highs in this

area. Deposits of alluvial sand and gravel occur on the valley

floors adjacent to the major streams in the area.

Climate

The average annual precipitation in this area is 14 to 19

inches (355 to 485 millimeters). Most of the precipitation falls

during the growing season as frontal storms in spring and as

high-intensity, convective thunderstorms in summer.

Precipitation in winter occurs mostly as snow. The annual

snowfall is typically 20 to 48 inches (50 to 120 centimeters).

The average annual temperature is 43 to 49 degrees F (6 to 10

degrees C). The freeze-free period averages 160 days and ranges

from 145 to 180 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 4.6%; ground water, 0.0%

Livestock—surface water, 6.8%; ground water, 0.4%

Irrigation—surface water, 68.8%; ground water, 4.6%

Other—surface water, 13.9%; ground water, 0.9%

The total withdrawals average 90 million gallons per day

(340 million liters per day). About 6 percent is from ground

water sources, and 94 percent is from surface water sources. In

most years precipitation is inadequate for maximum plant

growth. Some irrigated land is along the Missouri River and on

the flood plains along its major tributaries. The surface water is

generally of good quality. It is a sodium bicarbonate type and is

soft.

This area has few shallow water developments. Most of the

water for livestock comes from surface runoff that flows into

dams or from deep artesian flows from wells finished in

Dakota Sandstone. Because of high amounts of dissolved

solids, mostly sodium, chloride, and sulfate, the well water is

slightly saline or moderately saline. It is very hard and is

suitable only for watering livestock. High levels of selenium

and molybdenum in the runoff from the shale plains may

cause some health problems for livestock. Rural water systems

are improving the quality of the water available for domestic

use. The Missouri River is the source of water for these

systems.

Soils

The dominant soil orders in this MLRA are Entisols,

Inceptisols, Mollisols, and Vertisols. The soils in the area

dominantly have a mesic soil temperature regime, an ustic soil

moisture regime, and smectitic mineralogy. They are shallow to

very deep, generally well drained, and clayey. Ustorthents

(Okaton and Sansarc series) formed in residuum on breaks, hills,

and ridges. In some areas the residuum is mixed with alluvium.

Ustifluvents (Wendte series) and Argiustolls (Kirley series)

formed in alluvium on flood plains and terraces. Haplustepts

(Chantier and Dupree series) and Calciustepts (Lakoma series)

formed in residuum on plains and ridges. Haplustolls (Ottumwa

series) formed in clayey sediments on uplands. Haplusterts

formed in alluvium on fans, terraces, and valley floors

(Bullcreek series); in residuum on uplands (Millboro and Opal

series); and in clayey sediments on uplands, fans, and terraces

(Promise series).

Biological Resources

The vegetation in this area is a transition between tall prairie

grasses and mixed prairie grasses. Green needlegrass, western

wheatgrass, needleandthread, porcupinegrass, little bluestem,

and big bluestem are the major species. Bluestems,

buffalograss, sedges, and sideoats grama are dominant on the

shallower soils. Bur oak, buffaloberry, and prairie rose are

common along the major streams. Prairie cottonwood and a

variety of willow species are common on the flood plains along

the major streams.

Some of the major wildlife species in this area are mule deer,

white-tailed deer, antelope, turkey, pheasant, sharp-tailed

grouse, and prairie chicken.
174 Major Land Resource Areas

63B—Southern Rolling Pierre Shale

Plains

This area (shown in fig. 63B-1) is in South Dakota (82

percent) and Nebraska (18 percent). It makes up about 4,460

square miles (11,565 square kilometers). The towns of Winner,

Kennebec, Chamberlain, and Pickstown, South Dakota, are in

this area. Interstate 90 crosses the northernmost part of the area.

Several Indian reservations are in this MLRA, including the

Lower Brule, Crow Creek, Santee, and Yankton Indian

Reservations.

Physiography

Almost all of this area is in three different sections of the

Great Plains Province of the Interior Plains. Most of the area is

in the Missouri Plateau, Unglaciated, Section. This part of the

MLRA is an area of old plateaus and terraces that have been

deeply eroded. It is nearly level to rolling and has long, smooth

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 23%

Grassland—private, 63%; Federal, 6%

Forest—private, 1%

Urban development—private, 1%

Water—private, 5%

Other—private, 1%

Most of this area is in farms or ranches. Urban expansion is

limited. The area is used mainly for livestock production and

cash-grain farming. Alfalfa, sorghum, and hay are the principal

crops grown for livestock feed. Winter wheat is the main cash

crop; spring wheat and sunflowers are grown to a lesser extent.

Dryfarming soils that are not suited to cultivation is destroying

the native grassland.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and

productivity of the soils, and management of soil moisture.

Conservation practices on cropland generally include systems

of crop residue management (especially no-till systems that

reduce the need for summer fallow tillage), cover crops,

windbreaks, vegetative wind barriers, wind stripcropping, and

nutrient management.

The most important conservation practice on rangeland is

prescribed grazing. Generally, cultural treatments are not used

to increase forage production on the rangeland in this area.

Cool-season tame pastures are established to supplement

forage production. Haying commonly provides feed during

the winter. 

slopes and a well defined dendritic drainage system. Rivers and

creek valleys have smooth floors and steep walls.

The northeast corner of the MLRA, east of the Missouri

River, is in the Missouri Plateau, Glaciated, Section, and the

southwest tip is in the High Plains Section. The glaciated

section is very similar to the unglaciated section. Some of the

higher areas have deposits of glacial drift. The topography of

the High Plains Section is typified by nearly level and broad

intervalley remnants of smooth fluvial plains.

The southeast tip of the MLRA is in the Dissected Till Plains

Section of the Central Lowland Province of the Interior Plains.

The topography is very similar to that of the Missouri Plateau,

Glaciated, Section, but the original surface is a till plain rather

than an old plateau.

Elevation ranges from 1,310 to 1,640 feet (400 to 500

meters) on the bottom land along the Missouri River and from

1,310 to 1,970 feet (400 to 600 meters) on the shale plain

uplands. The areas that are cropped are mainly at an elevation

of about 1,640 feet (500 meters).

Figure 63B-1: Location of MLRA 63B in Land Resource Region G.
of the United States 175

most years precipitation is inadequate for maximum plant

growth. Some irrigated land is along the Missouri River and on

the flood plain along the White River. The water in the

Missouri River generally is of good quality. It is a sodium

bicarbonate type and is soft. High loads of suspended

sediments cause water-quality problems in the White River and

in some of the smaller tributaries to the Missouri River.

There are few shallow water developments in this area, and

most of the water for livestock comes from surface runoff that

flows into dams or from deep artesian flows from wells finished

in Dakota Sandstone. Because of high amounts of dissolved

solids, mostly sodium, chloride, and sulfate, the well water is

slightly saline or moderately saline. It is very hard and is

suitable only for watering livestock. Rural water systems are

improving the quality of water available for domestic use. The

Missouri River is the source of water for these systems.

Soils

The dominant soil orders in this MLRA are Entisols,

Inceptisols, Mollisols, and Vertisols. The soils in the area

dominantly have a mesic soil temperature regime, an ustic soil

moisture regime, and mixed or smectitic mineralogy. They are

shallow to very deep, generally well drained, and loamy or

clayey. Ustorthents formed in residuum (Okaton and Sansarc

series) or loess (Crofton series) on uplands and breaks.

Haplustepts (Labu series) formed in residuum on uplands.

Haplustolls (Nora and Thurman series) formed in eolian

sediments. Argiustolls (Bazile and Reliance series) formed in

loess and other silty sediments on uplands and stream terraces.

Well drained Argiustolls (Canning and Ree series) formed on

isolated high terraces along rivers and creeks. Haplusterts

(Promise and Opal series) formed in clayey sediments

weathered from clayey shale. Poorly drained Epiaquerts (Kolls

series) formed in upland depressions.

Biological Resources

The vegetation in this area is a transition between tall prairie

grasses and mixed prairie grasses. Green needlegrass,

porcupinegrass, and big bluestem are the major species. Little

bluestem, buffalograss, sideoats grama, and sedges are

dominant on the shallow soils. Buffaloberry, skunkbush sumac,

and prairie rose are common on steep slopes along the major

streams. Prairie cottonwood and a variety of willow species are

common on flood plains along the major streams. Green ash,

boxelder, chokecherry, bur oak, and buffaloberry occur in draws

and narrow valleys.

Some of the major wildlife species in this area are mule deer,

coyote, bobcat, sharp-tailed grouse, magpie, mallard, gadwall,

pintail, and blue-winged teal.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Missouri-White (1014), 79 percent; Niobrara (1015), 15

percent; and Missouri-Big Sioux (1017), 6 percent. The

Missouri River and the breaks along the river are in this MLRA.

The river runs through the north part of the MLRA and then

along the east edge. The confluence of the White and Missouri

Rivers is in this area. The lower reach of the Niobrara River, in

Nebraska, also is in this area. Lake Francis Case, Fort Randall

Dam, and Lewis and Clark Lake are in this MLRA. Lewis and

Clark Lake formed behind Gavins Point Dam, which is outside

this MLRA, in an area near Yankton, South Dakota. Gavins

Point Dam is the last and farthest downstream of the five mainstem dams on the Missouri River.

Geology

Cretaceous Pierre Shale underlies most of this area. This is a

marine sediment having layers of volcanic ash that have been

altered to smectitic clays. These clays shrink as they dry and

swell as they become wet, causing significant problems for road

and structural foundations. The younger Niobrara Chalk is in

the southern part of this area. Some glacial drift remnants are in

the northeast corner of the area, east of the Missouri River.

Alluvial sand and gravel underlie the valley floors along the

major streams.

Climate

The average annual precipitation in this area is 17 to 25

inches (430 to 635 millimeters). Most of the precipitation falls

during the growing season as frontal storms in spring and as

high-intensity, convective thunderstorms in summer.

Precipitation in winter occurs mostly as snow. The annual

snowfall is typically 16 to 46 inches (40 to 115 centimeters).

The average annual temperature is 45 to 50 degrees F (7 to 10

degrees C). The freeze-free period averages 165 days and ranges

from 145 to 185 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 5.6%; ground water, 2.7%

Irrigation—surface water, 33.8%; ground water, 7.9%

Other—surface water, 45.9%; ground water, 4.0%

The total withdrawals average 57 million gallons per day

(215 million liters per day). About 15 percent is from ground

water sources, and 85 percent is from surface water sources. In
176 Major Land Resource Areas

64—Mixed Sandy and Silty Tableland

and Badlands

This area (shown in fig. 64-1) is in South Dakota (42

percent), Nebraska (41 percent), and Wyoming (17 percent). It

makes up about 11,895 square miles (30,825 square

kilometers). The town of Kadoka, South Dakota, is in the

northern part of this area. The towns of Pine Ridge, South

Dakota, and Chadron, Alliance, and Scottsbluff, Nebraska, are

in the southern part of the area. The town of Lusk, Wyoming, is

in the southwestern part of the area. Interstate 90 goes through

the northernmost part of the area, in South Dakota. The

Nebraska National Forest, the Badlands National Park, parts of

the Oglala and Buffalo Gap National Grasslands, the Agate

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 27%

Grassland—private, 59%; Federal, 2%

Forest—private, 3%

Urban development—private, 1%

Water—private, 6%

Other—private, 2%

Most of this area is in ranches or farms. About three-fifths of

the area is rangeland that is grazed primarily by livestock. A

little more than one-fourth of the area is cropland. The major

enterprise is cash-grain farming. Winter wheat is the main crop,

and sunflowers, soybeans, and spring wheat are grown to a

lesser extent. In other parts of the area, the crops are grown

mainly as feed and forage for livestock. Irrigated corn is grown

in areas where the supply of water is adequate and the soils are

suitable.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and

productivity of the soils, and management of soil moisture.

Conservation practices on cropland generally include

systems of crop residue management (especially no-till systems

that reduce the need for summer fallow tillage), cover crops,

windbreaks, vegetative wind barriers, wind stripcropping, and

nutrient management. The most important conservation

practice on rangeland is prescribed grazing. Generally, cultural

treatments are not used to increase forage production on the

rangeland in this area. Cool-season, tame pastures are

established to supplement forage production. Haying

commonly provides supplemental feed during winter. Forest

stand improvement and firebreaks reduce the hazard of

wildfires on forestland and improve forest growth, quality,

health, and productivity. Fossil Beds National Monument, Chadron State Park, Fort

Robinson State Park, and the Pine Ridge Indian Reservation are

in this MLRA. The Badlands are internationally renowned for

their Oligocene vertebrate fossils.

Physiography

The northern half of this MLRA is in the Missouri Plateau,

Unglaciated, Section of the Great Plains Province of the

Interior Plains. This part of the MLRA is an area of old plateaus

and terraces that have been deeply eroded. The southern half of

the MLRA is in the High Plains Section of the same province

and division. The topography in this part of the MLRA is

typified by nearly level and broad intervalley remnants of

smooth fluvial plains. The Pine Ridge escarpment separates the

two areas. The area north of the escarpment is strongly sloping

but becomes less sloping as distance from the escarpment

increases. Local relief is generally less than 30 feet (9 meters).

Figure 64-1: Location of MLRA 64 in Land Resource Region G.
of the United States 177

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 5.0%; ground water, 17.1%

Irrigation—surface water, 19.1%; ground water, 25.5%

Other—surface water, 11.2%; ground water, 22.1%

The total withdrawals average 39 million gallons per day

(1,985 million liters per day). About 65 percent is from ground

water sources, and 35 percent is from surface water sources.

Most of the area depends on the rather low and erratic

precipitation for water. Some surface water for irrigation is

obtained from the Niobrara and White Rivers in Nebraska. This

water is of good quality. It contains less total dissolved solids

than the local ground water. It is a sodium bicarbonate type and

is hard or very hard.

Ground water is scarce and of poor quality in most of the

area. Locally, mainly south of Pine Ridge and in Nebraska,

underground sand and gravel in the Ogallala and Arikaree

Formations yield moderate to large quantities of good-quality

water. The level of total dissolved solids is typically less than

400 parts per million (milligrams per liter) in South Dakota,

but the sodium levels are high. This water is the least

mineralized ground water in South Dakota but is still hard or

very hard. Selenium concentrations from the underlying Pierre

Shale can exceed the standards for drinking water. Water for all

uses is pumped from the Arikaree Formation in Nebraska. This

water is less mineralized than that in South Dakota and is not so

hard. It is a sodium bicarbonate type and does not contain

selenium.

Soils

The dominant soil orders in this MLRA are Entisols,

Inceptisols, and Mollisols. The soils in the area dominantly

have a mesic soil temperature regime, an ustic or aridic soil

moisture regime, and mixed mineralogy. They are shallow to

very deep, generally well drained or somewhat excessively

drained, and loamy or sandy. Ustorthents (Fairburn and

Mittenbutte series) formed in residuum on uplands.

Ustipsamments (Dankworth series) formed in sandy eolian

sediments on dunes. Argiustolls (Alliance, Hemingford, and

Rosebud series) formed in loess and residuum on uplands.

Haplustolls formed in residuum on uplands (Busher, Oglala,

and Ponderosa series) and in alluvium and eolian deposits on

alluvial fans, stream terraces, and hills (Jayem and Vetal series).

Ustifluvents (Interior series) and Haplustepts (Cedarpass series)

formed in sodium-rich alluvial deposits and residuum in the

Badlands.

In the Pine Ridge and Badlands regions, however, relief is 100

to 300 feet (30 to 90 meters), and the bottom land along the

Niobrara River is 100 to 200 feet (30 to 60 meters) below the

surrounding hills and escarpments. Elevation ranges from

2,950 to 3,940 feet (900 to 1,200 meters), increasing gradually

from east to west. It is highest on a nearly level to gently

sloping tableland south of the narrow, steep-walled valleys near

Pine Ridge. The Badlands consist of eroded walls and

escarpments, small grass-covered tablelands and mesas, and

basins in which there are scattered eroded buttes. Slopes range

from nearly level to very steep. Many streams and gullies cut

the Badlands.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Missouri-White (1014), 47 percent; Niobrara (1015), 30

percent; North Platte (1018), 14 percent; and Cheyenne (1012),

9 percent. The headwaters of the White and Niobrara Rivers are

in the part of this MLRA in northwestern Nebraska. The White

River is the main drainage through the Badlands National Park.

Tributaries to the White River carved the badlands in the

northwest corner of the MLRA.

Geology

Tertiary continental sediments consisting of sandstone,

siltstone, and claystone underlie most of this area. Locally,

these units are called the Ogallala Group and the Arikaree

Group. Many of the bedrock units in the southern third of the

area are covered by loess. Sand, silt, and clay alluvium is under

the valley floors of the major drainages. The Pine Ridge

escarpment marks the northern extent of the Ogallala aquifer.

This is the most extensive and heavily used aquifer on the high

plains between the Rocky Mountains and the Mississippi

River. The Badlands consist of stream-laid layers of silt, clay,

and sand mixed with layers of volcanic ash. They are

internationally famous for their Oligocene fossil assemblages

and as a tourist destination.

Climate

The average annual precipitation in this area is 13 to 19

inches (330 to 485 millimeters). Most of the rainfall occurs as

frontal storms in spring and early summer. Some high-intensity,

convective thunderstorms occur in late summer. Precipitation in

winter occurs as snow. Much of this area receives about 35

inches (90 centimeters) of snow annually, but the snow seldom

covers the ground for more than a week at a time. The average

annual temperature is 43 to 51 degrees F (6 to 10 degrees C).

The freeze-free period averages about 150 days and ranges from

125 to 180 days.
178 Major Land Resource Areas

Biological Resources

This area supports a mixture of short, mid, and tall grasses.

Blue grama, western wheatgrass, threadleaf sedge, sideoats

grama, little bluestem, prairie sandreed, switchgrass, sand

bluestem, and needleandthread are the major species. On Pine

Ridge, these plants grow in association with ponderosa pine,

eastern redcedar, western snowberry, skunkbush sumac,

common chokecherry, and rose. Numerous woody draws occur

in this area and support such species as green ash, boxelder,

hackberry, chokecherry, bur oak, buffaloberry, and green muhly.

The eroded walls and escarpments of the Badlands are devoid

of vegetation.

Some of the major wildlife species in this area are mule deer,

white-tailed deer, pronghorn antelope, coyote, beaver, raccoon,

skunk, turkey, opossum, muskrat, mink, jackrabbit, cottontail,

weasel, prairie dog, prairie grouse, mourning dove,

meadowlark, and lark bunting.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 22%

Grassland—private, 60%; Federal, 11%

Forest—private, 4%

Urban development—private, 1%

Other—private, 2%

Most of this area is in ranches or farms. More than threefifths of the area is rangeland that is grazed primarily by

livestock. Scenic Pine Ridge has grassed areas and pine trees of

commercial value. About 20 percent of the area is cropland.

South of Pine Ridge, the major enterprise is cash-grain farming

and winter wheat is the main crop. In other parts of the area, the

crops are grown mainly as feed and forage for livestock.

Irrigated corn and sugar beets are grown in areas where the

supply of water is adequate and the soils are suitable. The

Badlands National Park is a major tourist attraction in the

northern part of this MLRA.

The main resource concerns are wind erosion, water erosion,

and the quality of surface water. Wind erosion and water erosion

are hazards on cropland and hayland and in areas of pasture and

rangeland where the plant cover is depleted by overgrazing.

Additional soil resource concerns are maintenance of the

content of organic matter and tilth of the soils and soil moisture

management.

The important conservation practices on cropland are

cropping systems that include high-residue crops, systems of

crop residue management (such as no-till and mulch-till

systems), level terraces, contour farming, contour stripcropping,

irrigation water management, and nutrient management. The

most important conservation practice on rangeland is

prescribed grazing. Generally, cultural treatments are not used

65—Nebraska Sand Hills

This area (shown in fig. 65-1) is in Nebraska (98 percent) and

South Dakota (2 percent). It makes up about 20,545 square

miles (53,235 square kilometers). It has no major cities. The

towns of Ainsworth, Mullen, and Valentine, Nebraska, are in

this area. Several national wildlife refuges occur in this area,

including Lacreek, Fort Niobrara, Valentine, and Crescent Lake

National Wildlife Refuges. The Samuel R. McKelvie and

Nebraska National Forests are in the area. This MLRA is the

Figure 65-1: Location of MLRA 65 in Land Resource Region G.

to increase forage production on the rangeland in this area.

Cool-season, tame pastures are established to supplement

forage production. Haying commonly provides supplemental

feed during winter. Forest stand improvement and firebreaks

reduce the hazard of wildfires on forestland and improve forest

growth, quality, health, and productivity. 
of the United States 179

largest sand-dune area in the Western Hemisphere and is one of

the largest grass-stabilized dune regions in the world.

Physiography

This area is in the High Plains Section of the Great Plains

Province of the Interior Plains. Elevation ranges from 1,970 to

3,940 feet (600 to 1,200 meters), increasing gradually from east

to west. Most of the area occurs as rolling to steep, irregular

sand dunes stabilized by grasses and as narrow, elongated,

nearly level to gently sloping valleys between the sand dunes.

The height of the dunes ranges from 10 to 400 feet (3 to 120

meters). The dunes and narrow valleys commonly extend for

several miles in a northwest-southeast direction. Many small

depressions are in scattered areas. The area has few streams but

has many small permanent and intermittent lakes.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Loup (1021), 45 percent; Niobrara (1015), 24 percent; North

Platte (1018), 16 percent; Elkhorn (1022), 9 percent; Platte

(1020), 4 percent; and Missouri-White (1014), 2 percent. The

Niobrara River is near the northern boundary of the area. It

provides opportunities for river rafting. The North Platte River

runs along the southwest edge of the MLRA. The North and

Middle Loup Rivers and the Calamus, Snake, and Dismal

Rivers are in the central and eastern parts of the MLRA.

Geology

This area consists of Quaternary sand dunes. The sands are

derived from the underlying Tertiary Ogallala and Arikaree

Groups. These units formed when rivers deposited sediments

that originated as erosional detritus following the uplift of the

Rocky Mountains to the west. The Ogallala aquifer underlies

this area. It is the most extensive and heavily used aquifer on

the high plains between the Rocky Mountains and the

Mississippi River. The major recharge area for this aquifer is the

Sand Hills.

Climate

The average annual precipitation in this area is 15 to 26

inches (380 to 660 millimeters). About three-fourths of the

precipitation falls from the middle of spring to the middle of

autumn. The rainfall occurs as frontal storms in spring and early

summer and high-intensity, convective thunderstorms in late

summer. Precipitation in winter occurs as snow. The average

annual temperature is 46 to 50 degrees F (8 to 10 degrees C).

The freeze-free period averages 155 days and ranges from 140

to 175 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 2.2%; ground water, 8.0%

Irrigation—surface water, 19.6%; ground water, 63.8%

Other—surface water, 4%; ground water, 2.4%

The total withdrawals average 840 million gallons per day

(3,180 million liters per day). About 74 percent is from ground

water sources, and 26 percent is from surface water sources.

Precipitation is the source of water for range vegetation. The

many small lakes and ponds and a few streams provide water for

livestock, some irrigation, and domestic use. The surface water

is of excellent quality and is suitable for all uses.

The Sand Hills is a primary recharge area for the Ogallala

aquifer. Ground water from the Ogallala aquifer is abundant and

of good quality. It is a calcium bicarbonate type and is very

hard. It is very low in total dissolved solids (less than 200 parts

per million or milligrams per liter) in this area. Because of the

abundance of surface water for livestock and domestic use, the

ground water is used primarily for irrigation in the flatter areas

of the MLRA.

Soils

The dominant soil orders in this MLRA are Entisols and

Mollisols. The soils in the area dominantly have a mesic soil

temperature regime, an ustic or aridic soil moisture regime, and

mixed mineralogy. They generally are very deep, excessively

drained to somewhat poorly drained, and sandy. Ustipsamments

formed in sandy eolian material on dunes (Valentine series) and

a mixture of sandy eolian material and sandy alluvial material

on hummocks and terraces (Ipage series) and in swales (Els series).

Haplustolls formed in sandy eolian material in areas between

dunes and on stream terraces (Dailey and Dunday series) and in a

mixture of sandy eolian material and sandy alluvial material in

swales and on stream terraces (Elsmere series).

Biological Resources

This area supports mid and tall grasses. Little bluestem, sand

bluestem, prairie sandreed, switchgrass, Indiangrass, sand

lovegrass, and needleandthread are the major species on uplands.

Big bluestem, switchgrass, Indiangrass, prairie cordgrass, and

various sedges and rushes grow on soils having a high water table.

Some of the major wildlife species in this area are whitetailed deer, mule deer, pronghorn antelope, black-tailed

jackrabbit, coyote, upland sandpiper, western meadowlark,

sharp-tailed grouse, and greater prairie chicken. The species of
180 Major Land Resource Areas

66—Dakota-Nebraska Eroded Tableland

This area (shown in fig. 66-1) is in Nebraska (56 percent) and

South Dakota (44 percent). It makes up about 5,660 square

miles (14,665 square kilometers). The town of Springview,

Nebraska, is in the central part of the area, and O’Neill,

Nebraska, is in the southeastern part. The town of Winner, South

Dakota, is just north of the MLRA, and the town of Valentine,

Nebraska, is just outside the southwest corner. U.S. Highways

18, 20, 83, and 183 cross the area. A portion of the Rosebud

Indian Reservation is in the northwestern part of the MLRA.

Physiography

The northern half of this MLRA is in the Missouri Plateau,

Unglaciated, Section of the Great Plains Province of the Interior

Plains. The southern half is in the High Plains Section of the

same division and province. This MLRA is part of the fluvial

plain that built up to the east as the Rocky Mountains eroded.

Broad intervalley remnants of that smooth fluvial plain

fish in the area include sunfish, drum, minnow, catfish, perch,

bluegill, and carp.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 5%

Grassland—private, 89%; Federal, 3%

Urban development—private, 1%

Water—private, 1%

Other—private, 1%

More than nine-tenths of this area is in large ranches, most of

which support native grasses grazed by livestock. Tracts along

streams and in subirrigated valleys are used mainly for hay. The

rolling hills and dry valleys are grazed. Use of sprinkler

irrigation has increased in recent years. Corn is the principal

irrigated crop.

The major soil resource concern on rangeland is wind

erosion in areas where the plant cover has been depleted by

overgrazing. The major soil resource concerns on cropland are

wind erosion, maintenance of the content of organic matter and

tilth of the soils, and soil moisture management.

Conservation practices on rangeland generally include

proper range management and improvement practices, such as

proper grazing use, deferment or rest periods, planned grazing

systems, range seeding or interseeding, and weed control. The

important conservation practices on cropland are cropping

systems that include high-residue crops, systems of crop residue

management (such as no-till and mulch-till systems), irrigation

water management, and nutrient management. 

Figure 66-1: Location of MLRA 66 in Land Resource Region G.

dominate the area. Some terraces and river breaks and local

badlands are along the major drainages. Elevation ranges from

1,970 to 2,950 feet (600 to 900 meters). The higher parts of the

tableland are nearly level to moderately sloping. Steeper areas

are on the sides of ridges and drainages. Stream valleys are well

defined, except in some undulating areas where sandy eolian

sandy material mantles the bedrock.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Niobrara (1015), 82 percent; Missouri-White (1014), 16

percent; and Elkhorn (1022), 2 percent. The Keya Paha,

Elkhorn, and Niobrara Rivers flow through this area. The

Niobrara is a National Scenic River.

Geology

The Cretaceous Niobrara Formation underlies most of this

area. It is made up of layers of marine sediments, mostly shaly

chalk and limestone. Some eolian deposits are on the surface in

the western and southern parts of the area. Alluvial sand and

gravel underlie the valley floors along the major streams.
of the United States 181

Ustipsamments (Valentine series) formed in sandy eolian

material on dunes.

Biological Resources

This area supports mixed prairie vegetation. Little bluestem,

prairie sandreed, green needlegrass, and needleandthread are

the dominant species. Sideoats grama and plains muhly are

important species on shallow soils. Leadplant and prairie rose

grow on the sides of draws. Hackberry and green ash grow in

the draws in some areas.

Some of the major wildlife species in this area are mule deer,

white-tailed deer, coyote, beaver, raccoon, opossum, muskrat,

mink, tree squirrel, prairie dog, turkey, pheasant, prairie grouse,

meadowlark, lark bunting, bobwhite quail, and mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 27%

Grassland—private, 65%; Federal, 1%

Forest—private, 3%

Urban development—private, 2%

Other—private, 2%

Most of this area supports native grasses and is grazed by

cattle. Some of the smoother areas are used for crops, mainly

corn, forage and grain sorghum, and alfalfa for livestock feed.

Winter wheat is grown as a cash crop in a few areas.

The major resource concerns are erosion and the quality of

surface water. The major soil resource concerns on cropland and

hayland are wind erosion, water erosion, maintenance of the

content of organic matter and tilth of the soils, and soil

moisture management. The major soil resource concerns on

pasture and rangeland are wind erosion and water erosion in

areas where the plant cover has been depleted by overgrazing.

The most important conservation practice on rangeland is

prescribed grazing. Generally, cultural treatments are not used

to increase forage production on the rangeland in this area.

Cool-season, tame pastures are established to supplement

forage production. The most important conservation practices

on cropland are cropping systems that include high-residue

crops, systems of crop residue management (such as no-till and

mulch-till systems), level terraces, contour farming, contour

stripcropping, irrigation water management, and nutrient

management. 

Climate

The average annual precipitation in this area is 18 to 25

inches (455 to 635 millimeters). Most of the rainfall occurs as

high-intensity, convective thunderstorms during the growing

season. Precipitation in winter occurs mainly as snow. The

annual snowfall ranges from about 24 to 40 inches (610 to

1,015 millimeters). Summers are hot, and winters are cold. The

average annual temperature is 46 to 49 degrees F (8 to 9

degrees C). The freeze-free period averages 160 days and ranges

from 145 to 175 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 0.3%; ground water, 0.7%

Irrigation—surface water, 26.0%; ground water, 63.1%

Other—surface water, 8.9%; ground water, 1.1%

The total withdrawals average 220 million gallons per day

(833 million liters per day). About 65 percent is from ground

water sources, and 35 percent is from surface water sources.

Because of the limited amount of precipitation, farming is risky

and maximum crop production is not expected in most years.

Most of the soils are deficient in moisture during much of the

latter part of the growing season. The surface water is of good

quality. It is a calcium, magnesium, and bicarbonate type and is

very hard. The level of total dissolved solids averages about

390 parts per million (milligrams per liter). The Niobrara River,

the only perennial stream in the area, provides water for

irrigation, livestock, domestic uses, and public supply.

Throughout most of the area, shallow water is available in

quantities sufficient for livestock and domestic uses. Most of

the shallow water is from sand and gravel deposits in drainages.

The Niobrara Formation supplies ground water for irrigation,

livestock, and domestic uses. This unit typically is considered

an aquifer only where solution channels and fractures have

opened the rock. The ground water is a calcium bicarbonate

type and is very hard. The level of total dissolved solids

averages about 490 parts per million (milligrams per liter).

Soils

The dominant soil orders in this MLRA are Entisols and

Mollisols. The soils in the area dominantly have a mesic soil

temperature regime, an ustic or aridic soil moisture regime, and

mixed mineralogy. They generally are very deep, well drained

to excessively drained, and loamy or sandy. Haplustolls formed

in eolian sediments (Anselmo and Dunday series) and loamy

over sandy sediments (Meadin, O’Neill, and Pivot series) on

stream terraces and uplands and in valleys. Argiustolls (Jansen

series) formed in loamy sediments over alluvium on uplands.

67A—Central High Plains, Northern Part

This area (shown in fig. 67A-1) is in Wyoming (68 percent),

Nebraska (29 percent), and Colorado (3 percent). It makes up

about 8,165 square miles (21,150 square kilometers). The cities
182 Major Land Resource Areas

Figure 67A-1: Location of MLRA 67A in Land Resource Region G.

of Cheyenne and Wheatland, Wyoming, are in this MLRA.

Interstate 80 skirts the southern edge of the MLRA.

Physiography

This area occurs primarily in the High Plains Section of the

Great Plains Province of the Interior Plains. The higher parts of

the tableland are nearly level to moderately sloping, but steeper

areas are on the sides of ridges and drainageways. Drainages are

well defined, except in some undulating areas where sandy

eolian material mantles the bedrock. In most of the MLRA,

elevation ranges from 3,200 to 5,500 feet (975 to 1,675 meters).

In some areas, however, it is as high as 7,400 feet (2,255

meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

North Platte (1018), 80 percent, and South Platte (1019), 20

percent. Parts of the North Platte and Laramie Rivers occur in

this MLRA.

Geology

This MLRA is dominated by residual geologic materials.

Large areas of eolian and alluvial deposits, however, occur in

parts of the MLRA. Sandstone and conglomerate are the

dominant rock types. The Tertiary White River, Upper

Miocene Rock, and Lower Miocene Rock Formations are

dominant in the MLRA. The Cretaceous Lance Formation

occurs as small areas in the western part the MLRA. Quaternary

alluvial and eolian deposits and gravel pediments occur in

some areas.

Climate

The average annual precipitation in this area ranges from 12

to 19 inches (305 to 485 millimeters). Much of the

precipitation occurs as rain in the period April through July.

The rain falls during convective thunderstorms. The driest

period is usually November through February. The average

annual temperature ranges from 43 to 50 degrees F (6 to 10

degrees C). The freeze-free period averages 145 days and ranges

from 130 to 165 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.8%; ground water, 1.2%

Livestock—surface water, 0.2%; ground water, 0.3%

Irrigation—surface water, 62.3%; ground water, 19.5%

Other—surface water, 14.6%; ground water, 1.1%

The total withdrawals average 1,795 million gallons per day

(6,795 million liters per day). About 22 percent is from ground

water sources, and 78 percent is from surface water sources.

Water for range vegetation and dryfarming is provided by the

low and erratic precipitation. Irrigation water is obtained

mostly from reservoirs on the North Platte River and its

tributaries. The surface water is of good quality and has few

limitations affecting its use.

All four of the principal aquifer types in Wyoming occur in

this area. Most of the ground water is pumped from the alluvial

aquifer along the North Platte River and its tributaries and from

the High Plains (Ogallala) aquifer. These unconsolidated and

consolidated sand and gravel aquifers yield adequate quantities

of ground water for livestock and domestic use, some irrigation,

and some other uses. Water from the alluvial aquifer is the

hardest water in the State of Wyoming but has a median

concentration of total dissolved solids of less than 500 parts per

million (milligrams per liter). Wells in the High Plains aquifer

provide high yields of water that has the lowest median

concentration of total dissolved solids in the State (260 parts
of the United States 183

per million or milligrams per liter). The water from both

aquifers is hard. In areas where shale bedrock is near the surface,

ground water is scarce and commonly of poor quality. The

Structural Basin and sandstone and carbonate bedrock aquifers

also occur in this area but are not utilized because of the readily

available water in the shallow aquifers.

Soils

The dominant soil orders in this MLRA are Mollisols and

Entisols. The dominant soil temperature regime is mesic, and

the dominant soil moisture regime is ustic. The soils receiving

less than 14 inches (355 millimeters) of precipitation annually

have an aridic soil moisture regime that borders on ustic. Some

soils with a frigid soil temperature regime occur in the far

western part of the MLRA, above an elevation of about 6,100

feet (1,860 meters). Soils with mixed mineralogy are dominant.

Most of the soils in the MLRA are sandy or loamy. The MLRA

has many areas of soils that are shallow or moderately deep to

sandstone or very gravelly layers. Deep soils that formed in

slope, alluvial, or eolian deposits are common. Soils near major

drainageways formed in stream- or river-deposited alluvium.

Most of the soils are well drained, but poorly drained or

somewhat poorly drained soils occur on the flood plains along

the major rivers. Most of the soils are calcareous.

Some of the most extensive and representative great groups

are Torriorthents, Haplustolls, Argiustolls, Calciustolls, and

Haplargids. Some of the most extensive and representative

series are Altvan, Ascalon, Vetal, Mitchell, Dwyer, Keeline,

Jayem, Tassel, Turnercrest, Treon, Manter, and Dunday series.

Biological Resources

This area supports cool- and warm-season grassland

vegetation. Rhizomatous wheatgrasses, needleandthread, and

blue grama are the dominant species on deep soils. Rhizomatous

wheatgrasses, little bluestem, bluebunch wheatgrass, Indian

ricegrass, and needleandthread are the major species on shallow

soils on hills and ridges. Sandy soils have a plant community that

includes prairie sandreed, sand bluestem, and sagebrush. A few

areas of shallow soils on steep escarpments have a plant

community that includes Rocky Mountain juniper and/or

ponderosa pine. Basin wildrye, green needlegrass, big bluestem,

rhizomatous wheatgrasses, and shrubs are dominant on the

bottom land along streams and rivers.

Some of the major wildlife species in this area are deer,

antelope, coyote, beaver, muskrat, jackrabbit, cottontail rabbit,

geese, ducks, and turkeys. The species of fish in the area

include walleye, bass, catfish, and rainbow trout.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 30%

Grassland—private, 65%; Federal, 3%

Urban development—private, 1%

Other—private, 1%

Most of this area is grazed by cattle. The rangeland is

primarily warm- and cool-season prairie, but areas of shallow or

sandy soils support shrubs. About 30 percent of the area is

cropland. The main irrigated crops are corn, alfalfa, beans, and

sugar beets. The main nonirrigated crop is winter wheat. The

irrigated crops are grown where irrigation water is available

from rivers or ground water sources. Nonirrigated small grain

crops are grown in areas with level to moderately sloping soils

that can store an adequate amount of soil moisture and that

receive an adequate amount of precipitation.

The major resource concerns are wind erosion and the

quality of water in streams, rivers, and aquifers. The quantity of

water for irrigating crops is a concern in some areas.

The important conservation practices on cropland are those

that reduce the hazard of wind erosion, improve the efficiency

of irrigation water use, and protect ground water from

contamination by leached nutrients and pesticides. The

important conservation practices on rangeland are those that

improve the health of the soil and plant communities and

improve the distribution of livestock. 

67B—Central High Plains, Southern Part

This area is entirely in Colorado (fig. 67B-1). It makes up

about 19,855 square miles (51,445 square kilometers). Denver,

Fort Collins, Greeley, Fort Morgan, Limon, and Springfield are

in this MLRA. Interstates 25, 76, and 70 bisect the northern part

of the area. The Pawnee and Comanche National Grasslands

occur in the area. Gas and oil fields are in scattered areas

throughout the MLRA. The greatest concentration of these

fields is in the Denver Basin area.

Physiography

Most of this area is in the Colorado Piedmont Section of the

Great Plains Province of the Interior Plains. The rest is in the

Raton Section of the same province and division. This MLRA

is on an elevated, smooth to slightly irregular plain consisting

of sediments deposited by rivers that drained the young and

actively eroding Rocky Mountains. This old plain is now a

dissected peneplain with a few dissected, lava-capped plateaus

and buttes. Elevation ranges from 3,000 to 7,800 feet (915 to

2,380 meters), increasing gradually from east to west. In many

areas the undulating to rolling shale plain is mantled by loess

or windblown sand, alluvium, and outwash. Wide bands of

steep slopes border several of the larger tributaries of the South
184 Major Land Resource Areas

Platte and Arkansas Rivers. Local relief is mostly less than 80

feet (25 meters) but is as much as 165 feet (50 meters) in some

of the rough, broken areas.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

South Platte (1019), 49 percent; Upper Arkansas (1102), 23

percent; Republican (1025), 15 percent; Upper Cimarron

(1104), 11 percent; and Smoky Hill (1026), 2 percent. The

South Platte and Arkansas Rivers bisect this MLRA as they

flow east into Nebraska and Kansas.

Geology

Cretaceous and Quaternary sediments cover approximately

equal areas of the surface of this MLRA. Rolling sandy plains

and dune areas are throughout the MLRA. Eolian and alluvial

deposits cover large areas of the South Platte River drainage.

Cretaceous Pierre Shale is at the surface in much of the area

north of the Arkansas River. The older Niobrara Chalk is

exposed closer to the river, and the even older Dakota

Sandstone is exposed south of the river. Some scattered

outcrops of Jurassic and Triassic sandstone, shale, and siltstone

also are south of the Arkansas River. These units are commonly

reddish. About half of the area is covered by river-laid

continental sediments consisting of loose to well cemented

sand and gravel with some silts and clays. Much of the

Quaternary alluvium has been reworked into dunes and loess

caps by the wind. The Tertiary Ogallala Formation occurs at the

far eastern edges of this MLRA. Quaternary and more recent

sand and gravel deposits cover the shale and chalk in the river

valleys.

Climate

The average annual precipitation in this area is 12 to 18

inches (305 to 455 millimeters), increasing from west to east.

The amount of precipitation fluctuates widely from year to year.

Rainfall occurs as frontal storms in spring and early summer

and high-intensity, convective thunderstorms in late summer.

The maximum precipitation occurs from the middle of spring

through late autumn. Precipitation in winter occurs as snow.

The average annual temperature is 45 to 55 degrees F (7 to 13

degrees C). The freeze-free period averages 160 days and ranges

from 135 to 190 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 5.5%; ground water, 1.2%

Livestock—surface water, 1.5%; ground water, 0.2%

Irrigation—surface water, 61.1%; ground water, 26.6%

Other—surface water, 2.5%; ground water, 1.3%

The total withdrawals average 4,135 million gallons per day

(15,650 million liters per day). About 29 percent is from ground

water sources, and 71 percent is from surface water sources.

Water for range vegetation and dryfarming is provided by the

low and erratic precipitation. Irrigation water is obtained

mostly from reservoirs on the South Platte River and its

tributaries in the northern part of the MLRA and from the

Arkansas River and its tributaries in the southern part. In the

western part of the MLRA, the surface water is of good quality

and has few limitations affecting its use. As more agricultural

drainage is returned to the rivers, the level of total dissolved

solids and sediment causes some water-quality problems in the

eastern part of the area.

The ground water used in the northern part of this area is

pumped from the alluvial aquifer along the South Platte River

and its tributaries. This unconsolidated and consolidated sand

and gravel aquifer yields large quantities of ground water for

irrigation, for some public supply, and for livestock and

domestic use. Water from the alluvial aquifer is a calcium

sulfate type and is very hard. Its level of total dissolved solids

Figure 67B-1: Location of MLRA 67B in Land Resource Region G.
of the United States 185

generally exceeds 1,000 parts per million (milligrams per liter).

Water quality is best along the edges of valleys where recharge

from adjacent aquifers occurs. The water degrades downstream

because of the addition of salts from irrigation return flows and

seepage from leaky ditches, reservoirs, and the river itself.

In the southern part of this area, a 1-to-5-mile-wide band of

alluvial deposits along the Arkansas River provides water for

livestock, public supply, and domestic uses and for local

irrigation. The median level of total dissolved solids in this

aquifer is 2,900 parts per million (milligrams per liter). The salt

content increases downstream to the point that the water can be

used only to irrigate salt-tolerant crops. The high amounts of

dissolved solids, especially sulfate, limit use of the water for

drinking. This water is very hard.

The deeper consolidated sand and gravel deposits in the

Denver Basin aquifer provide water for livestock, for some

domestic use, and for limited local irrigation. This aquifer

underlies the northwestern part of the area. The water generally

has more than 1,000 parts per million (milligrams per liter) total

dissolved solids. It is soft and generally contains sodium

bicarbonate and sulfate ions.

The High Plains aquifer occurs in the eastern part of this

MLRA. It provides water for irrigation, livestock, public

supply, and domestic uses. Wells provide water that is very low

in total dissolved solids, a median concentration of 230 parts

per million (milligrams per liter), north of the Arkansas River.

The water is a calcium bicarbonate type that is moderately hard

or hard. South of the Arkansas River, the median level of total

dissolved solids doubles and the water becomes more of a

sodium sulfate type. Naturally occurring levels of fluoride,

sulfate, and total dissolved solids in this part of the High Plains

aquifer commonly exceed the national standards for drinking

water. In areas where shale bedrock is near the surface, ground

water is scarce and commonly of poor quality.

Soils

The dominant soil orders in this MLRA are Mollisols,

Alfisols, Aridisols, and Entisols. The soils in the area

dominantly have a mesic soil temperature regime, an ustic or

aridic soil moisture regime, and mixed, carbonatic, or smectitic

mineralogy. They are very shallow to very deep, generally well

drained, and loamy or clayey. Argiustolls (Ascalon, Altvan, and

Nunn series) formed in alluvium along the major rivers.

Haplustalfs formed in loamy sediments (Baca series) and eolian

sediments (Vona and Wiley series) on hills and plains.

Haplargids (Olney series) formed in eolian sediments on hills

and plains. Ustorthents (Colby and Otero series) formed in loess

on hills and plains. Torriorthents formed in alluvium and/or

eolian sediments on alluvial fans, flood plains, and footslopes

(Thedalund and Rocky Ford series) and in residuum and/or

eolian sediments on hills, cuestas, and mesas (Minnequa,

Penrose, and Travessilla series).

Biological Resources

Most of this area supports short prairie grasses.

Needleandthread, prairie junegrass, blue grama, galleta, cholla,

threeawn, ring muhly, and alkali sacaton are the major species.

Cottonwood is common along the major streams. Stony and

rocky soils support a mixed stand of pinyon and juniper with

understory species similar to those in nearby openings and

grasslands. Sand sage is the potential natural vegetation on

rolling plains with grass-stabilized sand dunes and sheets.

Some of the major wildlife species in this area are mule deer,

antelope, jackrabbit, cottontail, turkey, pheasant, Canada

goose, scaled quail, bobwhite quail, and mourning dove. The

species of fish in the area include walleye, catfish, and crappie.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 28%

Grassland—private, 65%; Federal, 3%

Urban development—private, 1%

Other—private, 3%

Nearly all of this area is in farms or ranches. About two-thirds

of the area supports native short grasses used for grazing. Flood

plains and terraces along the Platte and Arkansas Rivers,

making up about one-fifth of the area, are irrigated. Alfalfa,

sugar beets, grain sorghum, melons, seed crops, corn, small

grains, onions, and other vegetables are the chief crops. Soils

that are frequently flooded and soils that are strongly affected

by salts generally are used for grazing. About one-tenth of the

area is dry-farmed. Winter wheat, dry beans, and grain sorghum

are the main crops.

A major soil resource concern is the loss of prime farmland

and cropland of statewide importance through conversion to

urban use. Additional concerns are wind erosion, water erosion,

surface compaction caused by tillage practices, increased

salinization of cropland caused by irrigation water management

practices, and overall degradation of soil quality.

Conservation practices on cropland generally include

irrigation water management, conservation tillage, crop

rotations, crop residue management, pest management, and

nutrient management. The most important conservation

practice on rangeland is prescribed grazing. 

69—Upper Arkansas Valley Rolling

Plains

This area is entirely in Colorado (fig. 69-1). It makes up

about 11,920 square miles (30,885 square kilometers). The city

of Pueblo and the towns of Rocky Ford, La Junta, and Lamar
186 Major Land Resource Areas

Figure 69-1: Location of MLRA 69 in Land Resource Region G.

are in this MLRA. Interstate 25 crosses the northwest corner of

the area. The Comanche National Grasslands occur in the area.

Many military installations are in this MLRA, including Fort

Carson, the High Speed Ground Testing Center, and the Pueblo

Ordinance Depot.

Physiography

The northern two-thirds of this area is in the Colorado

Piedmont Section of the Great Plains Province of the Interior

Plains. The rest is in the Raton Section of the same province

and division. This MLRA is an elevated plain consisting of

sediments deposited by rivers that drained the young and

actively eroding Rocky Mountains. This old plain is now a

dissected peneplain with a few dissected, lava-capped plateaus

and buttes. Elevation ranges from 3,600 to 6,230 feet (1,100 to

1,900 meters), increasing gradually from east to west. In many

areas the undulating to rolling shale plain is mantled by loess

or windblown sand, alluvium, and outwash. Wide bands of

steep slopes border several of the larger tributaries of the

Arkansas River. Local relief is mostly less than 80 feet (25

meters) but is as much as 165 feet (50 meters) in some of the

rough, broken areas.

The only Hydrologic Unit Area (identified by a four-digit

number) that makes up this MLRA is Upper Arkansas (1102).

The Arkansas River bisects this MLRA as it flows east into

Kansas.

Geology

Cretaceous and Quaternary sediments cover approximately

equal areas of the surface of this MLRA. The Cretaceous Pierre

Shale is at the surface in much of the area north of the Arkansas

River. The older Niobrara Chalk is exposed closer to the river,

and the even older Dakota Sandstone is exposed south of the

river. Some scattered outcrops of Jurassic and Triassic

sandstone, shale, and siltstone also are south of the Arkansas

River. These units commonly are reddish. About half of this

area is covered by river-laid continental sediments consisting

of loose to well cemented sand and gravel with some silts and

clays. Much of the Quaternary alluvium has been reworked into

dunes and loess caps by the wind. The Tertiary Ogallala

Formation occurs at the far eastern edges of this MLRA.

Quaternary and more recent sand and gravel deposits cover the

shale and chalk in the river valleys.

Climate

The average annual precipitation in this area is 10 to 19

inches (255 to 485 millimeters), increasing from west to east.

The amount of precipitation fluctuates widely from year to year.

Rainfall occurs as frontal storms in spring and early summer

and high-intensity, convective thunderstorms in late summer.

The maximum precipitation occurs from the middle of spring

through late autumn. Precipitation in winter occurs as snow.

The average annual temperature is 47 to 54 degrees F (8 to 12

degrees C). The freeze-free period averages 170 days and ranges

from 145 to 200 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.8%; ground water, 0.3%

Livestock—surface water, 2.0%; ground water, 0.3%

Irrigation—surface water, 68.7%; ground water, 26.1%

Other—surface water, 1.2%; ground water, 0.6%

The total withdrawals average 1,820 million gallons per day

(6,890 million liters per day). About 27 percent is from ground

water sources, and 73 percent is from surface water sources. The

low and erratic precipitation is the source of water for range

vegetation. Surface water quality in Colorado is typically

excellent. The Arkansas River and its larger tributaries provide
of the United States 187

water for irrigation and public supply along their valleys. A

number of reservoirs on tributaries to the Arkansas River

provide water for irrigation, public supply, livestock, and

domestic use.

In the northwest corner of this area, the deeper, consolidated

sand and gravel deposits (the Denver Basin aquifer) provide

water for livestock and some domestic use and for some limited

local irrigation. Water in the Denver Basin generally has more

than 1,000 parts per million (milligrams per liter) total

dissolved solids. It is soft and generally contains sodium

bicarbonate and sulfate ions. A 1-to-5-mile-wide band of

alluvial deposits along the Arkansas River provides water for

livestock, public supply, and domestic uses and for local

irrigation. North of the river, this ground water is a calcium

bicarbonate type and is very low in total dissolved solids (230

parts per million or milligrams per liter). South of the river, the

ground water changes to a sodium sulfate type and has twice

the total dissolved solids that occur north of the river. Another

alluvial aquifer, the High Plains aquifer, is in the far eastern part

of the MLRA. The water in this aquifer is normally not suitable

for drinking because it has high levels of naturally occurring

fluoride, sulfate, and total dissolved solids (more than 2,000

parts per million or milligrams per liter). Ground water is scarce

in most areas where shale is near the surface.

Soils

The dominant soil orders in this MLRA are Alfisols,

Aridisols, and Entisols. The soils in the area dominantly have a

mesic soil temperature regime, an ustic or aridic soil moisture

regime, and mixed, carbonatic, or smectitic mineralogy. They

are very shallow to very deep, generally well drained, and

loamy or clayey. Haplustalfs formed in loamy sediments (Baca

series) and eolian sediments (Vona and Wiley series) on hills

and plains. Haplargids (Olney series) formed in eolian

sediments on hills and plains. Ustorthents (Colby series) formed

in loess on hills and plains. Torriorthents formed in alluvium

and/or eolian sediments on alluvial fans, flood plains, and

footslopes (Limon, Manvel, and Rocky Ford series) and in

residuum and/or eolian sediments on hills, cuestas, and mesas

(Minnequa, Penrose, and Travessilla series).

Biological Resources

This area supports short prairie grasses. Blue grama, galleta,

cholla, threeawn, ring muhly, and alkali sacaton are the major

species. Cottonwood is common along the major streams. Stony

and rocky soils support a mixed stand of pinyon and juniper

with understory species similar to those in nearby openings and

grasslands.

Some of the major wildlife species in this area are mule deer,

antelope, jackrabbit, cottontail, turkey, pheasant, scaled quail,

bobwhite quail, and mourning dove. The species of fish in the

area include walleye, catfish, and crappie.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 11%

Grassland—private, 78%; Federal, 7%

Urban development—private, 2%

Water—private, 1%

Other—private, 1%

Nearly all of this area is in farms or ranches. More than threefourths of the area supports native short grasses and is used for

grazing. Flood plains and terraces along the Arkansas River,

making up about one-tenth of the area, are irrigated. Alfalfa,

sugar beets, grain sorghum, melons, seed crops, corn, small

grains, onions, and other vegetables are the chief crops. Soils

that are frequently flooded and soils that are strongly affected

by salts are used for grazing. Winter wheat, dry beans, and grain

sorghum are the main dry-farmed crops.

The major soil resource concerns are wind erosion, water

erosion, increased salinization of cropland because of

inefficient water management practices, surface compaction

resulting from tillage practices, and overall degradation of soil

quality.

Conservation practices on cropland generally include

irrigation water management, conservation tillage, crop

rotations, crop residue management, pest management, and

nutrient management. The most important conservation

practice on rangeland is prescribed grazing. 

70A—Canadian River Plains and Valleys

This area (shown in fig. 70A-1) is in northeastern New

Mexico (90 percent), southeastern Colorado (6 percent), the

Oklahoma Panhandle (3 percent), and northern Texas (1 percent).

It makes up about 10,770 square miles (27,910 square

kilometers). The towns of Las Vegas, Springer, and Raton, New

Mexico, are in this MLRA. Interstate 25 crosses the northwest part

of the area, and Interstate 40 crosses the southern tip. The Capulin

Volcano National Monument and some of the Comanche

National Grasslands are in the northeastern part of this area.

Physiography

Most of this area is in the Raton Section of the Great Plains

Province of the Interior Plains. The area is characterized by

broad, gently undulating to rolling piedmont plains with

extensive basalt flows and varying degrees of dissection. These

plains are interspersed with relatively smooth valleys and

basins. About 25 percent of the area is on steep or very steep

dissected slopes. These slopes are below the Canadian

escarpment and on the breaks along the Cimarron River in the

northern part of the area. Elevation ranges from 5,000 to 7,000
188 Major Land Resource Areas

feet (1,525 to 2,135 meters). A few isolated mountains and

mesas occur in the area. This MLRA includes the highest point

in Oklahoma, Black Mesa, which is at an elevation of 4,973

feet (1,516 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Upper Canadian (1108), 51 percent; Upper Cimarron (1104), 16

percent; Upper Pecos (1306), 15 percent; Lower Canadian

(1109), 11 percent; North Canadian (1110), 5 percent; and Rio

Grande-Elephant Butte (1302), 2 percent. The headwaters of the

Cimarron, Canadian, and Pecos Rivers cross this area.

Geology

The southwestern and western parts of this area are underlain

by Cretaceous shales of the Dakota, Graneros, and Pierre

Formations and, to a lesser extent, by Cretaceous limestones of

the Greenhorn Formation. The northern and eastern parts of the

area are underlain by Tertiary basalts and other volcanic rocks.

The northeastern part also is underlain by Cretaceous shales

and limestones of the Dakota, Graneros, and Pierre Formations.

Climate

The average annual precipitation in this area is 10 to 21

inches (255 to 535 millimeters), fluctuating widely from year to

year. Most of the rainfall occurs in spring and fall. The average

annual temperature is 46 to 58 degrees F (8 to 14 degrees C).

The freeze-free period averages 175 days and ranges from 130

to 215 days, increasing in length from northwest to southeast.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.7%; ground water, 0.8%

Livestock—surface water, 1.0%; ground water, 0.7%

Irrigation—surface water, 75.8%; ground water, 20.7%

Other—surface water, 0.1%; ground water, 0.1%

The total withdrawals average 70 million gallons per day

(265 million liters per day). About 22 percent is from ground

water sources, and 78 percent is from surface water sources.

Water is scarce throughout the area because of the low and

erratic precipitation and the few perennial streams. Most of the

surface water used in this area is from the Canadian and Pecos

Rivers and their headwater streams. The surface water is of good

quality because only a small amount of agricultural return

flows reaches the rivers.

The only major aquifer in this MLRA is the Eastern New

Mexico Basin Fill aquifer, in a small separate section of the area

where the Canadian River crosses the State border into Texas.

This aquifer is part of the High Plains (Ogallala) aquifer, which

is not actually a basin fill deposit but has water so similar in

quality to that of other basin fill aquifers that it is lumped with

them. Because of low levels of total dissolved solids, sodium,

and hardness, the ground water in this aquifer is very well

suited to agricultural use. Most of the ground water is pumped

from the alluvial deposits in valleys along the larger streams in

the area. The ground water is of good enough quality to be used

for domestic and livestock supplies and for some limited

irrigation. Small amounts of ground water are in fractures and

joints in the shale and sandstone bedrock on uplands.

Soils

The dominant soil orders in this MLRA are Mollisols,

Alfisols, and Entisols. Most of the soils are Ustolls, Orthents, or

Ustalfs. They are wel1 drained and moderately fine textured or

fine textured. They have a mesic soil temperature regime, an

ustic soil moisture regime, and mixed mineralogy. Deep

Argiustolls (Swastika, Partri, and Charette series) and

Haplustol1s (Colmor series) and moderately deep Argiustolls

(Carnero series) are on uplands. Deep Calciustol1s (Ayon series)

are on mesas and side slopes. Deep Torriorthents (Vermejo

series) and Haplustolls (Manzano series) are in drainageways

Figure 70A-1: Location of MLRA 70A in Land Resource Region G.
of the United States 189

and on valley floors. Shallow Haplustolls (Apache series) are on

basalt mesas, the upper side slopes, and ridges. Shallow

Haplustalfs (Sombordoro series) and Torriorthents (Travessilla

and Mion series) are on moderately rolling to steep hills, ridges,

and the side slopes of canyons.

Biological Resources

The native vegetation in this area consists of short or mid

prairie grasses in the lowlands and pinyon and juniper at the

higher elevations and on breaks. Fine textured soils support

vegetation characterized by western wheatgrass, blue grama,

sideoats grama, and galleta. Alkali sacaton and western

wheatgrass dominate drainageways. Soils along natural

escarpments and shallow soils support little b1uestem, sideoats

grama, and blue grama and species of oak, juniper, pinyon,

mountain mahogany, sumac, and Apache plume.

Some of the major wildlife species in this area are mule deer,

antelope, jackrabbit, cottontail, pheasant, bobwhite quail, and

mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 1%

Grassland—private, 76%; Federal, 3%

Forest—private, 13%

Urban development—private, 1%

Other—private, 6%

Farms or ranches make up nearly all of this area. The

principal enterprise is cattle grazing. About 1 percent of the

area is cropland. Small grains and grain sorghum are the

principal crops. Irrigated hay, pasture, and small grains are

grown in small tracts where irrigation water is provided by

wells and reservoirs.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter in the

soils, and management of soil moisture. Conservation practices

on rangeland generally include reasonable stocking rates and

pasture rotation. 

Figure 70B-1: Location of MLRA 70B in Land Resource Region G.

70B—Upper Pecos River Valley

This area (shown in fig. 70B-1) is in east-central New

Mexico (90 percent) and western Texas (10 percent). It makes

up about 9,900 square miles (25,660 square kilometers). The

towns of Tucumcari, Santa Rosa, and Fort Sumner, New Mexico,

are in this MLRA. Interstate 40 connects Tucumcari and Santa

Rosa, and numerous U.S. highways cross the area.

Physiography

Most of this area is in the Pecos Valley Section of the Great

Plains Province of the Interior Plains. The area is characterized

by piedmont plains and tablelands formed by sedimentary

rocks. It is dissected by terraced valleys along the Pecos and

Canadian Rivers. Gently undulating to rolling plains and

sandhills are interspersed with relatively smooth valleys and

basins. A few small mesas and buttes occur throughout the

MLRA. Elevation ranges from 3,700 to 5,300 feet (1,130 to

1,615 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Upper Pecos (1306), 50 percent; Upper Canadian (1108), 37

percent; and Lower Canadian (1109), 13 percent. The Pecos

and Canadian Rivers and many of their tributaries occur in this

area.
190 Major Land Resource Areas

Geology

This area is underlain primarily by sandstones and shales in

the Santa Rosa and Chinle Formations of Triassic age. The

southern part of the area has Quaternary alluvium, dunes,

terraces, and pediments in combination with shales and

sandstones of the Artesia Group of Permian age.

Climate

The average annual precipitation in most of this area is 13 to

15 inches (330 to 380 millimeters), f1uctuating widely from

year to year. It is 19 inches (485 millimeters) in the eastern onefourth of the area. Most of the precipitation occurs during

summer and fall. The average annual temperature is 54 to about

60 degrees F (12 to 16 degrees C). The freeze-free period

averages 205 days and ranges from 185 to 225 days, increasing

in length from north to south.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 0.3%; ground water, 0.6%

Irrigation—surface water, 93.9%; ground water, 4.7%

Other—surface water, 0.5%; ground water, 0.0%

The total withdrawals average 105 million gallons per day

(400 million liters per day). About 5 percent is from ground

water sources, and 95 percent is from surface water sources.

Water is scarce throughout the area because of the low and

erratic precipitation and the few perennial streams. Most of the

surface water used in the area is from reservoirs on the Canadian

and Pecos Rivers and their tributaries. The surface water is of

better quality in the northern part of the area than in the

southern part. The Pecos and Canadian Rivers become saltier as

more agricultural return flows, wastewater from oil and gas

development and potash mining operations, and saline seeps

discharge into the rivers and their tributaries.

A small part of the Pecos River Basin Limestone aquifer

underlies this area. The water from this aquifer is not of very

good quality. It is high in sulfate because it dissolves gypsum

within the aquifer. This sodium sulfate type of water is very

hard, and its median level of total dissolved solids exceeds

1,000 parts per million (milligrams per liter). Another source of

ground water is the alluvial deposits in the valleys along the

larger streams. This ground water is of good enough quality to

be used for domestic and livestock supplies and for some

limited irrigation. Small amounts of ground water are in

fractures and joints in the bedrock on uplands.

Soils

The dominant soil orders in this MLRA are Aridisols and

Entisols. Most of the soils are Argids, Calcids, Cambids, or

Orthents. They are well drained and coarse textured to fine

textured. They have a thermic soil temperature regime, an aridic

soil moisture regime, and gypsic, carbonatic, or mixed

mineralogy. Deep Calciargids and Haplargids (Redona,

Tucumcari, Faskin, and Berwolf series) formed on alluvial fan

terraces, plains, and uplands. Deep Haplocambids (Ima and La

Lande series) formed on fan terraces and piedmont slopes. Deep

Haplocalcids (Quay, Ratliff, Chispa, and Poquita series) formed

on fan terraces and uplands. Moderately deep Haplocalcids

(San Jon and Conchas series) and very deep Torriorthents

(Holloman series) formed on uplands. Deep Torrerts (Montoya

series) formed on flood plains. Deep Torriorthents (Lacita

series) formed on alluvial fans. Shallow Torriorthents (Lacoca

series) formed on ridges. Very deep Calcigypsids (Reeves series)

have gypsic mineralogy and formed mainly in nearly level to

gently sloping areas. Deep Torripsamments (Roswell series)

formed on dunes on terraces. Shallow and moderately deep

Petrocalcids (Kolar, Neso, and Pojo series) formed on mesas.

Biological Resources

The native vegetation in this area consists of short or mid

prairie grasses in the lowlands and pinyon and juniper at the

higher elevations and on the steeper north-facing slopes.

Upland sites are characterized by gramas, dropseeds, bluestems,

bristlegrass, and small soapweed. Depressional areas are

characterized by alkali sacaton, vine-mesquite, and galleta in

the northern part of the MLRA and tobosa in the southern part.

Bluestems, Indiangrass, and soapweed characterize the

sandhills, which also support sand sage in the northern part of

the MLRA and shinnery oak in the southern part.

Some of the major wildlife species in this area are mule deer,

antelope, coyote, kit fox, bobcat, badger, beaver, skunk,

muskrat, jackrabbit, cottontail, rock squirrel, pack rat, sandhill

crane, pheasant, raven, bobwhite quail, scaled quail, and box

turtle.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 2%

Grassland—private, 85%; Federal, 5%

Forest—private, 1%

Urban development—private, 1%

Water—private, 1%

Other—private, 5%
of the United States 191

70C—Central New Mexico Highlands

This area (shown in fig. 70C-1) is in central New Mexico (95

percent) and in Texas (5 percent). It makes up about 12,495

square miles (32,375 square kilometers). The towns of Moriarty,

Corona, and Carrizozo, New Mexico, and Pine Springs, Texas,

are in this MLRA. Interstate 40 crosses the northern end of the

MLRA. Areas of the Lincoln National Forest are in the southcentral and southwestern parts of this MLRA and in the

Guadalupe Mountains, which is in a separate part of the MLRA,

southeast of the main part. Outliers of the Cibola National

Forest are in the south-central and northwest parts of the area.

The Guadalupe Mountains National Park is in the part of this

area in Texas, and the western portion of the Carlsbad Caverns

National Park is in the separate, southwest part of the MLRA, in

New Mexico. The eastern one-fourth of the Mescalero Indian

Reservation is in the southern part of the area. Areas of the Fort

Bliss Military Reservation and the White Sands Missile Range

are in the far western part of the MLRA.

Physiography

This area is in the Sacramento Section of the Basin and

Range Province of the Intermontane Plateaus. It is characterized

by block-faulted ranges separated by intermountain basins.

Tablelands and mesas are capped by sedimentary rocks. Many

local terraces are near small streams. Steep escarpments and

breaks are common. Elevation generally ranges from 5,000 to

7,400 feet (1,525 to 2,255 meters). In some mountainous areas,

however, it is more than 8,500 feet (2,590 meters). It is 8,749

feet (2,667 meters) on Guadalupe Peak, the highest point in

Texas. This peak is in the part of this MLRA in the Guadalupe

Mountains National Park.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Upper Pecos (1306), 54 percent; Rio Grande Closed Basins

(1305), 38 percent; and Rio Grande-Elephant Butte (1302), 8

percent. Some western tributaries to the Pecos River cross this

area.

Geology

The northern one-third of this area is underlain by

Quaternary alluvium and sand dunes of Quaternary age with

minor exposures of basalt. The southern two-thirds is underlain

by sandstones, shales, and dolomites in the Permian-age

Glorieta and San Andres Formations.

Climate

The average annual precipitation in most of this area is 11 to

15 inches (280 to 380 millimeters), occurring mostly in

summer. It is as high as 26 inches (660 millimeters) in the

mountains. The average annual temperature is 46 to 60 degrees

F (8 to 16 degrees C). The freeze-free period averages 190 days

and ranges from 135 to 250 days, decreasing in length with

elevation.

Farms or ranches make up nearly all of this area. Cattle and

sheep grazing is the principal enterprise. About 2 percent of the

area is in irrigated cropland. Canals from reservoirs provide

irrigation water. The main irrigated crops are alfalfa, grain

sorghum, and wheat.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter in the

soils, and management of soil moisture. Conservation practices

on cropland generally include conservation tillage, crop

residue management, and irrigation water management.

Conservation practices on rangeland generally include

prescribed grazing, fencing, brush management, and

development of watering facilities. 

Figure 70C-1: Location of MLRA 70C in Land Resource Region G.
192 Major Land Resource Areas

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 0.0%; ground water, 0.7%

Irrigation—surface water, 33.5%; ground water, 65.5%

Other—surface water, 0.4%; ground water, 0.0%

The total withdrawals average 135 million gallons per day

(510 million liters per day). About 66 percent is from ground

water sources, and 34 percent is from surface water sources.

Water is scarce throughout the area because of the low and

erratic precipitation and the few perennial streams. Most of the

surface water used in this area is from the western tributaries of

the Pecos River. The surface water is generally of good quality

because it has not been contaminated by agricultural return

flows. Some local water-quality problems occur in areas where

wastewater from oil and gas development or potash mining is

discharged into the surface water.

A small part of the Pecos River Basin Limestone aquifer

underlies the northeastern and southeastern parts of this MLRA.

Most of the water from this aquifer is not of very good quality.

It is high in sulfate because it dissolves gypsum within the

aquifer. This sodium sulfate type of water is very hard, and its

median level of total dissolved solids exceeds 1,000 parts per

million (milligrams per liter). The Eastern New Mexico Basin

Fill aquifer is a source of ground water on the western edge of

the area. Because of low levels of total dissolved solids,

sodium, and hardness, this water is very well suited to most

uses. Another source of ground water is the alluvial deposits in

the valleys along the few large streams. The water from these

deposits is of good enough quality to be used for domestic and

livestock supplies and for some limited irrigation. Small

amounts of ground water are in fractures and joints in the

bedrock on uplands.

Soils

The dominant soil orders in this MLRA are Aridisols,

Entisols, and Mollisols. Most of the soils are Argids, Calcids,

Ustolls, or Orthents. They are well drained and are moderately

coarse textured to moderately fine textured. They have a mesic

soil temperature regime, an ustic or aridic soil moisture regime,

and carbonatic or mixed mineralogy. Generally, the moisture

regime is aridic bordering on ustic, but areas of pinyon-juniper

woodland and savanna at the higher elevations have an ustic

regime bordering on aridic.

Very deep Calciargids (Tapia, Clovis, and Witt series) and

very deep Haplargids (Penistaja series) formed on uplands. Very

deep Haplocalcids (Dean and Harvey series) formed on alluvial

fan terraces and mesas. Very deep, saline Haplocalcids (Willard

series) formed in lacustrine deposits on lake terraces. Very

shallow and shallow Calciustolls (Deama series) and

Haplustolls (Tortugas and Laporte series) formed on mesas and

hills underlain by limestone bedrock. Shallow Torriorthents

(Travessilla series) formed in sandy eolian deposits over

sandstone bedrock on hills. Very deep Torriorthents (Otero

series) formed in sandy alluvium locally reworked by the wind.

Shallow Petrocalcids (Pastura series) formed on mesas. Deep

Argiustolls (Romine series) formed in gravelly and cobbly

sediments on alluvial fan terraces. Deep Argiustolls (Rednun

series) formed in fine textured sediments on alluvial plains.

Biological Resources

The soils at the higher elevations are in areas of juniperpinyon savanna and pinyon-juniper woodland. They have a

diverse understory dominated by sideoats grama, little

bluestem, blue grama, bottlebrush squirreltail, western

wheatgrass, pinyon ricegrass, Bigelow sagebrush, and winterfat.

The soils at the lower elevations are characterized by a mixed

grassland prairie of little bluestem, grama grasses, western

wheatgrass, galleta, and New Mexico feathergrass. They also

support sand sagebrush and sumac. Alkaline soils support

fourwing saltbush, winterfat, and alkali sacaton. The

drainageways at the higher elevations are dominated by giant

sacaton, and those at the lower elevations are dominated by

western wheatgrass. Fourwing saltbush, winterfat, and alkali

sacaton also are prevalent in the drainageways.

Some of the major wildlife species in this area are badger,

porcupine, skunk, jackrabbit, cottontail, prairie dog, kangaroo

rat, pocket gopher, pocket mouse, sparrow hawk, red-tailed

hawk, Cooper’s hawk, marsh hawk, prairie falcon, scaled quail,

raven, western kingbird, horned lark, warbler, mourning dove,

and rattlesnake.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 1%

Grassland—private, 72%; Federal, 17%

Forest—private, 6%; Federal, 2%

Urban development—private, 1%

Other—private, 1%

Ranches make up most of this area. Cattle and sheep grazing

is the primary land use. Land ownership is about four-fifths

private and one-fifth Federal or State. Most of the area is a

rolling grassland prairie. Large areas adjacent to the mountains

are in pinyon-juniper savanna or pinyon-juniper woodland. A

small percentage of the area is irrigated cropland. Most of this

cropland is in the Estancia Basin.

The major soil resource concerns are wind erosion, water
of the United States 193

ranges from 180 to 255 days, increasing in length from west to

east.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 0.1%; ground water, 1.0%

Irrigation—surface water, 91.9%; ground water, 7.1%

Other—surface water, 0.0%; ground water, 0.0%

The total withdrawals average 70 million gallons per day

(265 million liters per day). About 8 percent is from ground

water sources, and 92 percent is from surface water sources.

Most of the surface water used in this area is from the western

70D—Southern Desert Foothills

This area is entirely in south-central New Mexico (fig. 70D-1).

It makes up about 3,000 square miles (7,775 square kilometers).

The towns of Carlsbad and Roswell are just outside this area to

the east. U.S. Highways 62 and 100 cross the southern end of this

area, and U.S. Highways 70 and 380 cross the northern end. The

eastern part of the Carlsbad Caverns National Park is in the

southeast corner of the area. A small part of Fort Bliss Military

Reservation is in the western tip of the area.

Physiography

This area is in the southern part of the Sacramento Section of

the Basin and Range Province of the Intermontane Plateaus. It

is characterized by nearly level to rolling or steep limestone

hills with intermittent drainageways. Small areas of nearly level

valley bottom land occur in the larger drainageways. Elevation

generally is 4,000 to 6,000 feet (1,220 to 1,830 meters) but is

8,000 feet (2,440 meters) in some areas.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Upper Pecos (1306), 75 percent; Rio Grande Closed Basins

(1305), 21 percent; and Lower Pecos (1307), 4 percent. Some

western tributaries to the Pecos River cross this area.

Geology

This area is underlain by limestones, sandstones, shales, and

dolomites in the Glorieta and San Andres Formations of

Permian age.

Climate

The average annual precipitation in this area is 12 to 22

inches (305 to 560 millimeters). The higher amount of

precipitation occurs along the eastern edge of the area. The

precipitation fluctuates widely from year to year. Most of the

precipitation is received from early summer to early autumn.

The average annual temperature is 51 to 63 degrees F (11 to

17 degrees C). The freeze-free period averages 215 days and

Figure 70D-1: Location of MLRA 70D in Land Resource Region G.

erosion, maintenance of the content of organic matter in the

soils, and management of soil moisture. Conservation practices

on cropland generally include conservation tillage, crop

residue management, and irrigation water management.

Conservation practices on rangeland generally include

prescribed grazing, fencing, brush management, and

development of watering facilities. 
194

tributaries of the Pecos River. The surface water generally is of

good quality because it has not been contaminated by

agricultural return flows. Some local water-quality problems

occur in areas where wastewater from oil and gas development

or potash mining is discharged into the surface water.

Part of the Pecos River Basin Limestone aquifer underlies

the eastern portion of this MLRA. Most of the water from

this aquifer is not of very good quality. It is high in sulfate

because it dissolves gypsum within the aquifer. This sodium

sulfate type of water is very hard, and its median level of total

dissolved solids exceeds 1,000 parts per million (milligrams

per liter). Another source of ground water is the alluvial

deposits in the valleys along the few large streams. This water

is of good enough quality to be used for domestic and livestock

supplies and for some limited irrigation. Small amounts of

ground water are in fractures and joints in the bedrock on

uplands.

Soils

The dominant soil orders in this MLRA are Aridisols and

Mollisols. Most of the soils are Calcids, Cambids, or Ustolls. They

are well drained and mostly shallow and loamy-skeletal. They

have a thermic soil temperature regime, an aridic soil moisture

regime, and carbonatic or mixed mineralogy. Rock outcrop makes

up a significant portion of the area. Shallow or very shallow

Calciustolls (Ector series) and Haplocalcids (Lozier series) are

underlain by limestone and are on hills. Shallow Petrocalcids

(Philder series) have a petrocalcic horizon and formed on fan

remnants. Very deep Haplocalcids (Armesa series) formed in

loamy fan alluvium on pediments and fan piedmonts. Very deep

Haplocambids (Reyab series) formed in silty alluvium in

drainageways and on terraces and alluvial fans.

Biological Resources

This area supports natural prairie vegetation characterized

by sideoats grama, black grama, blue grama, green sprangletop,

tridens, Metcalfe muhly, and a diversity of shrubs, such as

mariola, sumacs, catclaw, sotol, agave, and fourwing saltbush.

Drainageways are dominated by Apache plume, New Mexico

walnut, desertwillow, brickellbush, littleleaf sumac, hackberry,

and a few cottonwoods.

Some of the major wildlife species in this area are antelope,

badger, jackrabbit, cottontail, prairie dog, ground squirrel,

pocket gopher, kangaroo rat, golden eagle, Swainson’s hawk,

sparrow hawk, prairie falcon, scaled quail, burrowing owl,

meadowlark, horned lark, loggerhead shrike, mourning dove,

box turtle, prairie rattlesnake, western coachwhip snake, Texas

horned lizard, and plains spadefoot toad.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—private, 47%; Federal, 49%

Forest—Federal, 3%

Urban development—private, 1%

Most of this area is Federal land. The extreme western part is

dominantly in military use and ownership. The rest is used

primarily as rangeland grazed by cattle and sheep. Small tracts

in some of the stream valleys are irrigated.

The major soil resource concerns are the erosion caused by

overgrazing, maintenance of the content of organic matter in

the soils, and management of soil moisture. Conservation

practices on rangeland generally include reasonable stocking

rates and pasture rotation. 
195

Figure H-1: Location of Land Resource Region H.

H—Central Great Plains Winter Wheat

and Range Region

This region (shown in fig. H-1) is in Texas (35 percent),

Kansas (29 percent), Oklahoma (16 percent), Nebraska (13

percent), New Mexico (4 percent), and Colorado (3 percent).

Also, a very small part of the region is in Wyoming. This region

makes up 219,740 square miles (569,420 square kilometers).

This region is in the south-central part of the Great Plains. It

is a nearly level to gently rolling fluvial plain in the northern

part and more of an eroded plateau with entrenched streams in

the southern part. The average annual precipitation ranges from

20 to 29 inches (510 to 735 millimeters) in most of the region.

Most of the precipitation falls during spring and fall

thunderstorms. Snowfall provides only a small portion of the

annual precipitation. The average annual temperature ranges

from 54 to 60 degrees F (12 to 16 degrees C) in most of this

region. The freeze-free period ranges from 190 to 235 days,

increasing in length from north to south.

The total withdrawals of freshwater in this region average

about 17,560 million gallons per day (52,345 million liters per

day). About 73 percent is from ground water sources, and 27

percent is from surface water sources. About 91 percent of the

water is used for irrigation.

The soils in this region are dominantly Mollisols, but

significant acreages of Alfisols, Entisols, and Inceptisols also

occur. The dominant soil suborder is Argiustolls. Other notable

suborders include Haplustolls, Ustipsamments, Calciustolls,

Paleustolls, and Paleustalfs. Most of the soils in the region have

a mesic or thermic soil temperature regime and an ustic soil

moisture regime. Mineralogy is dominantly mixed but is

smectitic or carbonatic in some soils.

About 99 percent of the land in this region is privately

owned. The native vegetation consists mainly of mid and tall

prairie grasses, but some areas support short prairie grasses or a

mixture of these and other prairie grasses. Small areas of oaksavanna occur in the MLRAs in the southern part of the region.

The region has almost as much cropland as it has grassland. The

production of beef cattle is the dominant agricultural
196 Major Land Resource Areas

Figure H-2: Wheat in an area of Land Resource Region H.

enterprise. Dry-farmed winter wheat (fig. H-2) and other small

grains are grown for either cash or feed. Irrigated crops, mainly

corn, alfalfa, and forage crops, are grown along many of the

major streams.

The major resource concerns on the grassland in this region

are overgrazing and the spread of invasive plants and noxious

weeds. The major resource concerns on cropland are wind

erosion, water erosion, maintenance of the content of organic

matter in the soils, and soil moisture management. The quality

of surface water also is a concern. Sediment, nutrients,

pesticides, and salinity are the major nonpoint sources of

surface- and ground-water pollution. Control of saline seeps on

rangeland and salt management on irrigated land are concerns

in some areas of the region. 
of the United States 197

Figure 71-1: Location of MLRA 71 in Land Resource Region H.

71—Central Nebraska Loess Hills

This area is entirely in Nebraska (fig. 71-1). It makes up

about 8,165 square miles (21,160 square kilometers). The cities

of Kearney, Lexington, and Grand Island and the towns of

Broken Bow, Ord, Loup City, St. Paul, and Central City are in

this MLRA. Interstate 80 skirts the southern edge of this area.

Physiography

This MLRA is in the High Plains Section of the Great Plains

Province of the Interior Plains. This area is the eastern extent of

the fluvial plain created by the ancient rivers that drained the

rapidly eroding Rocky Mountains after the mountains were

uplifted. This smooth plain has been dissected by present-day

rivers, and thick deposits of loess derived from the fluvial plain

occur on ridges between the broad stream valleys. Elevation

ranges from 1,640 to 2,620 feet (500 to 800 meters), increasing

from east to west. Nearly level to gently sloping, loess-mantled,

narrow ridgetops are separated by steep slopes bordering

drainages. Some stream valleys have nearly level flood plains

and large stream terraces. Nearly level soils occur on high

stream terraces in the southern part of the area, in the Platte

River Valley. Local relief is 20 to 100 feet (5 to 30 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Loup (1021), 60 percent, and Platte (1020), 40 percent. The

Platte River runs along the southern edge of this MLRA, and

the North, Middle, and South branches of the Loup River join

to form the Loup River in this area.

Geology

Most of the uplands in this area are covered with thick

deposits of loess. Extensive terraces are in the valleys along the

Loup and Platte Rivers. These terraces contain silt, sand, and

gravel, and the river valleys are filled with Quaternary and

younger deposits of sand and gravel. The eastern extent of the

Tertiary Ogallala Formation underlies most of this MLRA.

Pierre Shale and Niobrara Chalk, Cretaceous marine sediments,

underlie the eastern edge of the area.

Climate

The average annual precipitation in this area is 21 to 29

inches (535 to 735 millimeters). Most of the precipitation falls

from spring through autumn, but the maximum occurs from late

spring to early summer. The rainfall occurs as frontal storms in

spring and early summer and high-intensity, convective

thunderstorms in late summer and early autumn. Precipitation

in winter typically occurs as snow. The average annual

temperature is 47 to 51 degrees F (8 to 11 degrees C). The

freeze-free period averages 165 days and ranges from 140 to

190 days, increasing in length from west to east.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 2.0%

Livestock—surface water, 0.2%; ground water, 0.7%

Irrigation—surface water, 25.1%; ground water, 55.9%

Other—surface water, 15.7%; ground water, 0.5%

The total withdrawals average 1,295 million gallons per day

(4,900 million liters per day). About 59 percent is from ground

water sources, and 41 percent is from surface water sources. The

low, erratic precipitation is the source of water for crops and

native grasses in most of the area. The Loup and Platte Rivers

provide water for irrigation along their valleys. This water is of

good quality and is suitable for all uses.

In much of the area, an abundant supply of good-quality

ground water is used for domestic purposes and livestock and

locally for irrigation. Ground water from Quaternary sand and
198 Major Land Resource Areas

gravel in valley fill aquifers and from eolian deposits of silt and

fine sand is similar in quality to the ground water from the

Tertiary Ogallala aquifer. It has less than 500 parts per million

(milligrams per liter) total dissolved solids. It is a calcium

bicarbonate type of water and is very hard. Gravity-irrigated

farmland is concentrated on the terraces and river valleys,

especially along the Platte River.

Soils

The dominant soil orders in this MLRA are Entisols and

Mollisols. The soils in the area dominantly have a mesic soil

temperature regime, an ustic soil moisture regime, and mixed

mineralogy. They are generally very deep, well drained to

excessively drained, and loamy or sandy. Ustorthents (Coly

series) formed in loess on uplands. Ustifluvents (Hobbs series)

formed in alluvium on flood plains and alluvial fans.

Ustipsamments (Valentine series) formed in sandy eolian

material on dunes. Haplustolls (Cozad, Hord, and Uly series)

formed in alluvium and/or loess on stream terraces and uplands.

Argiustolls formed in loess over alluvium on stream terraces

(Hall series) and in loess on uplands (Holdrege series).

Biological Resources

The uplands in this area support short, mid, and tall grasses.

Big bluestem, little bluestem, switchgrass, Indiangrass, sideoats

grama, blue grama, and western wheatgrass are the major

species on silty soils. Needleandthread, prairie sandreed, sand

bluestem, little bluestem, and blue grama are the major species

on sandy soils.

Some of the major wildlife species in this area are whitetailed deer, coyote, raccoon, opossum, cottontail, muskrat,

squirrel, mink, pheasant, prairie chicken, bobwhite quail, and

mourning dove. The species of fish in the area include bass,

bluegill, and channel catfish.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 44%

Grassland—private, 48%; Federal, 1%

Forest—private, 1%

Urban development—private, 3%

Water—private, 1%

Other—private, 2%

Nearly all of this area is in farms and ranches, and almost

two-fifths is dry-farmed. About one-half of the area supports

native grasses used for grazing. Winter wheat, grain sorghum,

and alfalfa are the major dry-farmed cash crops. Between 5 and

10 percent of the area, consisting of flood plains and terraces

along the Platte River and its larger tributaries, is irrigated.

Corn, soybeans, alfalfa, and seed crops are the principal

irrigated crops. Alfalfa is commercially grown in the Platte

River Valley.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and tilth

of the soils, and soil moisture management. The resource

concerns on rangeland are wind erosion and water erosion;

plant productivity, health, and vigor; and the spread of noxious

and invasive plant species.

Conservation practices on cropland generally include highresidue crops in the cropping system; systems of crop residue

management, such as no-till and mulch-till systems; level

terraces; contour farming; contour stripcropping; irrigation

water management; and nutrient management. Conservation

practices on rangeland generally include prescribed grazing,

brush management, proper distribution of watering facilities,

and control of noxious and invasive plant species. 

72—Central High Tableland

This area (shown in fig. 72-1) is in Kansas (54 percent),

Nebraska (25 percent), and Colorado (21 percent). A very small

part of the area is in Wyoming. The area makes up about 34,550

square miles (89,535 square kilometers). It includes the towns

of Garden City, Goodland, and Colby, Kansas; Imperial, North

Platte, Ogallala, and Sidney, Nebraska; and Holyoke and Wray,

Colorado. Interstate 70 bisects the area, and Interstates 76 and

80 follow the south side of the South and North Platte Rivers,

respectively. The Cimarron National Grasslands occur in the

southeast corner of the MLRA.

Physiography

Almost all of this area is in the High Plains Section of the

Great Plains Province of the Interior Plains. A small part of the

area, where the South Platte River enters Nebraska, is in the

Colorado Piedmont Section of the same province and division.

This MLRA consists of broad intervalley remnants of a smooth,

fluvial plain. Elevation ranges from 2,600 to 3,900 feet (795 to

1,190 meters), increasing from east to west. Slopes generally are

nearly level to gently rolling on this smooth tableland, but

steep slopes border the major valleys. Broad, level flood plains

and terraces are along the Arkansas and Platte Rivers and a few

of their larger tributaries. Local relief on uplands is in meters,

but valleys are tens of meters below the general level of the

uplands.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Republican (1025), 38 percent; Middle Arkansas (1103), 20

percent; Smoky Hill (1026), 15 percent; South Platte (1019), 13

percent; Upper Cimarron (1104), 11 percent; North Platte

(1018), 2 percent; and Upper Arkansas (1102), 1 percent. The
of the United States 199

North Platte River forms the northern boundary of this MLRA.

The South Platte River joins the North Platte River at the town

of North Platte, Nebraska. The Arkansas River bisects the

southern part of the MLRA. Other large rivers between the

North Platte and Arkansas Rivers in the area include the

Republican, Sappa, Prairie Dog, Solomon, Saline, and Smoky

Hill Rivers. The Cimarron River is in the southeast corner of the

area.

Geology

The smooth tableland lying between the major river valleys

in this MLRA has river-laid sediments washed out onto the

plains following uplift of the Rocky Mountains in Colorado. In

many areas the wind reworked these sediments, forming a

hummocky, dune surface of eolian sand. A loess mantle occurs

in other parts of the area. The Tertiary-age Ogallala and White

River Formations cover Cretaceous Pierre Shale. The Ogallala

Formation consists of loose to well cemented sand and gravel,

and the White River Formation consists of ashy claystone and

sandstone. The Pierre Shale can be near the surface in the river

valleys cut into the Tertiary sediments. Quaternary and more

recent sand and gravel cover the shale in the river valleys.

Climate

The average annual precipitation in this area is 14 to 25

inches (355 to 635 millimeters). It fluctuates widely from year

to year. Most of the rainfall occurs as high-intensity, convective

thunderstorms during the growing season. The maximum

precipitation occurs from late spring through early autumn.

Precipitation in winter occurs as snow. The annual snowfall

ranges from about 16 inches (40 centimeters) in the southern

part of the area to 35 inches (90 centimeters) in the northern

part. The average annual temperature is 46 to 57 degrees F (8 to

14 degrees C). The freeze-free period averages 175 days and

ranges from 135 to 210 days, increasing in length from

northwest to southeast.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.8%

Livestock—surface water, 0.3%; ground water, 0.6%

Irrigation—surface water, 23.2%; ground water, 73.5%

Other—surface water, 0.9%; ground water, 0.7%

The total withdrawals average 4,225 million gallons per day

(15,990 million liters per day). About 76 percent is from ground

water sources, and 24 percent is from surface water sources. The

low, erratic precipitation is the source of water for dry-farmed

crops and pastures on uplands. Water from the Arkansas,

Republican, and North and South Platte Rivers is used for

irrigation in the valleys of these rivers. The surface water is

generally of good quality. It is suitable for all in-stream uses

and for irrigation. In this MLRA, the quantity of the water is a

much greater problem than the quality. Water from the South

Platte River is highly mineralized because of irrigation use and

reuse in Colorado.

In most of this area, good-quality ground water is adequate

for domestic and livestock needs and is used locally for

irrigation. Ground water is scarce in areas where shale is near

the surface. Almost all of the ground water used for irrigation in

the uplands comes from Quaternary sand and gravel deposits

near the surface, the Ogallala Formation, and the Brule

Formation, all of which are part of the High Plains aquifer. This

water is typically low in total dissolved solids but is hard or

very hard. Some ground water is obtained from alluvium in the

principal river valleys. The water from the alluvial aquifers is

very hard. Shallow ground water can be contaminated by

nitrate and atrazine from agricultural lands.

Figure 72-1: Location of MLRA 72 in Land Resource Region H.
200 Major Land Resource Areas

Soils

The dominant soil orders in this MLRA are Entisols and

Mollisols. The soils in the area dominantly have a mesic soil

temperature regime, an ustic or aridic soil moisture regime, and

mixed or smectitic mineralogy. They generally are very deep

and moderately well drained to excessively drained. The

texture of the soils varies. Ustorthents (Colby and Sulco series)

and Haplustolls (Ulysses series) formed in loess on hills and

plains. Torripsamments (Valent series) formed in sandy eolian

material on dunes. Argiustolls formed in loess (Keith, Kuma,

and Richfield series) and loamy eolian and/or outwash

sediments (Manter and Satanta series) on hills, plains, and

stream terraces and in mixed loess and local alluvium on plains

and in drainageways and depressions (Rago series). Paleustolls

(Platner series) formed in pedisediments on plains and

tablelands.

Biological Resources

This area supports short prairie grasses. Blue grama and

buffalograss are the dominant species. Sideoats grama, blue

grama, hairy grama, and little bluestem grow on the steeper

valley walls along the major rivers.

Some of the major wildlife species in this area are whitetailed deer, antelope, coyote, badger, raccoon, skunk, rabbit,

prairie dog, pheasant, prairie chicken, quail, and mourning

dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 67%

Grassland—private, 30%

Urban development—private, 2%

Other—private, 1%

Nearly all of this area is in farms or ranches dominated by

cash-grain farming and livestock production. More than twothirds of the area is cropland used for dry-farmed crops. Winter

wheat, typically grown in a winter wheat-fallow rotation, is the

primary crop. Other small grains, grain sorghum, alfalfa, and

grass hay crops also are widely grown, especially in the narrow

irrigated areas along the Platte, Republican, and Arkansas

Rivers. Corn, grain sorghum, and sugar beets are grown

extensively on the nearly level uplands where ground water is

used for irrigation. Pinto beans are grown on some broad, flat

plains. Nearly one-third of the area, consisting of hilly and

steep slopes bordering the drainageways, supports native

grasses and shrubs used for grazing.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and tilth

of the soils, and soil moisture management. The resource

concerns on rangeland are wind erosion; plant productivity,

health, and vigor; the spread of noxious and invasive species;

and inadequate wildlife habitat.

Conservation practices on cropland generally include highresidue crops in the cropping system; systems of crop residue

management, such as no-till and mulch-till systems; level

terraces; contour farming; contour stripcropping; conservation

crop rotations; irrigation water management; and pest and

nutrient management. Conservation practices on rangeland

generally include prescribed grazing, brush management,

management of upland wildlife habitat, proper distribution of

watering facilities, and control of noxious and invasive plant

species. 

73—Rolling Plains and Breaks

This area (shown in fig. 73-1) is in Kansas (78 percent) and

Nebraska (22 percent). It makes up about 21,485 square miles

(55,670 square kilometers). The towns of Hays, Great Bend, and

Dodge City, Kansas, and Alma, Curtis, Holdrege, and McCook,

Nebraska, are in this MLRA. The MLRA is bisected by

Interstate 70. The Platte River is at the northern edge of the

area, and the Arkansas River is at the southern edge.

Physiography

Almost all of this area is in the Plains Border Section of the

Great Plains Province of the Interior Plains. The northwest and

southwest corners of the area are in the High Plains Section of

the same province and division. The surface of the area is a submaturely or maturely dissected plateau. Elevation ranges from

1,650 to 3,000 feet (505 to 915 meters), increasing from east to

west. The dissected plains in this area have broad, undulating

to rolling ridgetops and hilly to steep valley sides. The valleys

are generally narrow, but broad flood plains and terraces are

along the Republican River and its larger tributaries. Local

relief is in meters to tens of meters.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Smoky Hill (1026), 48 percent; Republican (1025), 30 percent;

Middle Arkansas (1103), 19 percent; and Platte (1020), 3

percent. The North Platte River forms the northern boundary of

the MLRA, and the Republican River parallels the NebraskaKansas border. The Arkansas River bisects the southern part of

the area. Other large rivers between the Republican and

Arkansas Rivers in this area include the Sappa, Prairie Dog,

Solomon, Saline, and Smoky Hill Rivers. Medicine Creek is in

the northwestern part of the area.
of the United States 201

Figure 73-1: Location of MLRA 73 in Land Resource Region H.

Geology

The western half of this MLRA and areas along the Arkansas

River have remnants of the Tertiary river-laid sediments washed

out onto the plains from erosion of the prehistoric Rocky

Mountains in Colorado. In the valley of the Arkansas River, the

wind reworked these sediments, forming a hummocky dune

surface of eolian sand. A loess mantle occurs on the higher

ground in the western half of the area. The Tertiary-age Ogallala

and White River Formations cover Cretaceous Pierre Shale in

the northern part of the area. The Ogallala Formation consists of

loose to well cemented sand and gravel, and the White River

Formation consists of ashy claystone and sandstone. Pierre

Shale and Niobrara Chalk are at the surface in the valleys of the

Republican, Smoky Hill, and Saline Rivers. Fort Hays

limestone and Blue Hill shale of the Niobrara Formation are at

the surface in the valleys of the Saline and Smoky Hill Rivers.

Shale is exposed in most of the eastern half of this MLRA, in

Kansas. Quaternary and more recent sand and gravel partially

cover the shale in the river valleys.

Climate

The average annual precipitation in this area is 19 to 30

inches (485 to 760 millimeters). Most of the rainfall occurs as

high-intensity, convective thunderstorms during the growing

season. The maximum precipitation occurs from the middle of

spring to early autumn. Precipitation in winter occurs as snow.

The annual snowfall ranges from about 17 inches (45

centimeters) in the southern part of the area to 24 inches (60

centimeters) in the northern part. The average annual

temperature is 48 to 56 degrees F (9 to 14 degrees C). The

freeze-free period averages 180 days and ranges from 145 to

210 days, increasing in length from northwest to southeast.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.1%; ground water, 0.9%

Livestock—surface water, 0.2%; ground water, 1.4%

Irrigation—surface water, 12.2%; ground water, 77.9%

Other—surface water, 7.0%; ground water, 0.4%

The total withdrawals average 1,400 million gallons per day

(5,300 million liters per day). About 81 percent is from ground

water sources, and 19 percent is from surface water sources. The

moderate, erratic precipitation is the source of water for crops

and pasture in much of the area. The amount of surface water is

limited throughout the area. The Republican and Platte Rivers

and their larger tributaries provide surface water for irrigation

along their valleys. The surface water is generally of good

quality. It is suitable for all in-stream uses and for irrigation.

Because of low flows, the rivers in Kansas are limited as sources

of irrigation water.

Abundant supplies of ground water for irrigation and other

uses are obtained from wells, primarily in the northern part of

this MLRA. Alluvium in the valleys along the major rivers and

their larger tributaries is one source of ground water, and

Quaternary sand and gravel and the Ogallala Formation within

the High Plains aquifer are other sources. The water from the

Ogallala Formation is typically low in total dissolved solids

but is hard or very hard. The water from the alluvial aquifers is

very hard. Shallow ground water can be contaminated by

nitrate and atrazine from agricultural lands. Some deeper wells

have been drilled to obtain more saline water from the Dakota

Formation. Ground water becomes scarce in the eastern half of

the MLRA, where the High Plains aquifer has been eroded away

and Cretaceous Pierre Shale and Niobrara Chalk are at, or close

to, the surface.
202 Major Land Resource Areas

Soils

The dominant soil order in this MLRA is Mollisols. Entisols

are of lesser extent. The soils in the area dominantly have a

mesic soil temperature regime, an ustic soil moisture regime,

and mixed or smectitic mineralogy. They are shallow to very

deep, moderately well drained to somewhat excessively

drained, and loamy or clayey. Haplustolls formed in mixed

loess, alluvium, and residuum on footslopes (Armo series), in

mixed loess and alluvium on stream terraces (Hord and Eltree

series), in alluvium on flood plains and alluvial fans

(Bridgeport and Roxbury series), in loess on uplands (Uly

series), and in residuum on hills and plains (Nibson and

Wakeen series). Calciustolls (Penden series) formed in loamy

sediments on uplands in the western part of the area. Argiustolls

(Harney, Holdrege, and Spearville series) and Ustorthents (Coly

series) formed in loess on uplands.

Biological Resources

This area supports natural prairie vegetation. Little

bluestem, big bluestem, switchgrass, western wheatgrass, and

sideoats grama characterize the vegetation on loamy soils. Blue

grama, buffalograss, and western wheatgrass characterize the

vegetation on clayey soils on uplands.

Some of the major wildlife species in this area are mule deer,

white-tailed deer, coyote, raccoon, pheasant, bobwhite quail,

mourning dove, and meadowlark. The species of fish in the area

include bass, bluegill, catfish, and bullhead.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 55%

Grassland—private, 39%; Federal, 1%

Forest—private, 1%

Urban development—private, 2%

Water—private, 1%

Other—private, 1%

Nearly all of this area is in farms or ranches. More than half

of the area is cropland used for dry-farmed crops. Winter wheat

and grain sorghum are the major crops in much of the area.

Corn is the main crop in the northern part of the area. Feed

grains and hay crops also are widely grown. About 2 percent of

the area, especially on the terraces and narrow bottom land

along the Platte and Republican Rivers, is irrigated. Corn,

alfalfa, small grains, and grass for hay are grown extensively on

the irrigated land. About 40 percent of the area, consisting of

hilly and steep slopes bordering the drainageways, supports

native grasses and shrubs used for grazing.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter in the

soils, and surface compaction. Also, soil moisture management

is important in the western part of the area. The resource

concerns on rangeland are plant productivity, health, and vigor;

the spread of noxious and invasive plants; and inadequate

wildlife habitat.

Conservation practices on cropland generally include highresidue crops in the cropping system; systems of crop residue

management, such as no-till, strip-till, and mulch-till; level

terraces in the western part of the area and gradient terraces and

grassed waterways in the eastern part; contour farming;

conservation crop rotations; irrigation water management; and

nutrient and pest management. Conservation practices on

rangeland generally include prescribed grazing, brush

management, management of upland wildlife habitat, proper

distribution of watering facilities, and control of noxious and

invasive plant species. 

74—Central Kansas Sandstone Hills

This area is entirely in Kansas (fig. 74-1). It makes up about

8,365 square miles (21,675 square kilometers). The city of

Salina and the towns of Concordia, Junction City, McPherson,

and Newton are in this MLRA. Interstate Highways 70 and 135

meet in Salina, and Interstate 35 crosses the southern part of

this area. Wilson and Kanopolis State Parks are in this area.

McConnell Air Force Base is in the southern part of the area.

Physiography

The northwest half of this area is in the Plains Border

Section of the Great Plains Province of the Interior Plains. The

northeast corner is in the Dissected Till Plains Section of the

Central Lowland Province of the Interior Plains, and the rest of

the area is in the Osage Plains Section of the same province and

division. This area is an undulating to hilly, dissected plain.

Wide flood plains and terraces are along the larger rivers, and

narrow bottom land is along the small streams. Elevation is

generally 1,310 to 1,640 feet (400 to 500 meters), increasing

from east to west. Local relief is typically 65 to 130 feet (20 to

40 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Smoky Hill (1026), 47 percent; Middle Arkansas (1103), 22

percent; Kansas (1027), 11 percent; Republican (1025), 10

percent; and Neosho-Verdigris (1107), 10 percent. The Little

Arkansas River forms the southwestern border of this area. From

north to south, other rivers that cross the area include the Little

Blue, Big Blue, Republican, Solomon, Salt, Saline,

Cottonwood, Walnut, and Arkansas Rivers. The Solomon and

Saline Rivers join the Smoky Hill River just south of Salina.
of the United States 203

Figure 74-1: Location of MLRA 74 in Land Resource Region H.

Geology

This area is underlain by Cretaceous sandstone bedrock that

dips gently to the east. The bedrock is exposed in a number of

areas. Shale occurs in a few places. Loess deposits mantle the

uplands, and deposits of unconsolidated sand and some gravel

occur in the major stream and river valleys. The area south of

central Kansas is underlain by unconsolidated sediments and

Cretaceous-age soft sandstone and shale. The eastern edge of

the area is underlain by Permian limestone deposits that form

the Flint Hills region to the east.

Climate

The average annual precipitation in this area is 26 to 33

inches (660 to 840 millimeters). Most of the precipitation falls

from spring through autumn, but the maximum is in

midsummer. The rainfall typically occurs as high-intensity,

convective thunderstorms. The annual snowfall averages almost

20 inches (50 centimeters). The average annual temperature is

52 to 56 degrees F (11 to 13 degrees C). The freeze-free period

averages 200 days and ranges from 190 to 210 days.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 6.6%; ground water, 5.7%

Livestock—surface water, 0.3%; ground water, 4.2%

Irrigation—surface water, 70.8%; ground water, 0.5%

Other—surface water, 12.0%; ground water, 0.0%

The total withdrawals average 210 million gallons per day

(795 million liters per day). About 10 percent is from ground

water sources, and 90 percent is from surface water sources. If

moisture is carefully conserved, the moderate precipitation

generally is adequate for crops and pasture. The surface water is

generally suitable for most uses with appropriate treatment.

Water is stored in reservoirs outside this area for public supply,

industry, and irrigation within this area. Some in-stream

diversions also are used.

Ground water is adequate to meet domestic and livestock

needs in most of the area and is used locally for irrigation,

industry, and public supply. Most of the ground water used in

this area is from the unconsolidated sediments in the valleys

along the three large rivers that cross the area. The level of total

dissolved solids is generally more than 500 and less than 1,000

parts per million (milligrams per liter). The water is very hard

and requires softening when used to meet industry and

domestic needs. As freshwater is removed, brine moving up into

this aquifer from deeper marine sediments can increase the

salinity of the water in the alluvial aquifer. The water can be

contaminated mainly because of agricultural chemicals,

irrigation return flows, and the production of oil and gas in the

area. Municipal waste discharges and seepage and runoff from

landfills are concerns around Salina.

Sandstone in the Great Plains aquifer is another source of

rural and domestic water. Where it is close to the surface, the

water in this aquifer is low in total dissolved solids. At depth,

the levels of sulfate and chloride increase and the water

becomes more saline and unsuitable for most uses. This water is

very hard.

Ground water from the Chase and Council Grove aquifer is

used for rural and domestic supply and some public supply.

This water is very hard but is suitable for most uses. In some

areas the levels of total dissolved solids and sulfate are high but

do not limit use of the water. The water is briny on the western

edge of the area. Ground water is scarce in areas where shale

and clay are near the surface.
204 Major Land Resource Areas

Figure 75-1: Location of MLRA 75 in Land Resource Region H.

Soils

The dominant soil order in this MLRA is Mollisols. The

soils in the area dominantly have a mesic soil temperature

regime, an ustic soil moisture regime, and mixed or smectitic

mineralogy. They are shallow to very deep, moderately well

drained to somewhat excessively drained, and loamy or clayey.

Haplustolls formed in residuum on uplands (Hedville series)

and in alluvium on flood plains and stream terraces (Hord and

Tobin series). Argiustolls formed in residuum on uplands

(Edalgo, Lancaster, and Wells series) and in loess on uplands

and stream terraces (Crete, Geary, Hastings, and Longford

series).

Biological Resources

This area supports mid and tall grasses. Little bluestem, big

bluestem, switchgrass, sideoats grama, and western wheatgrass

are the major species.

Some of the major wildlife species in this area are whitetailed deer, cottontail, pheasant, prairie chicken, bobwhite

quail, and mourning dove. The species of fish in the area

include largemouth bass, bluegill, crappie, carp, channel

catfish, flathead catfish, walleye, northern pike, white bass, and

striped bass.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 52%

Grassland—private, 38%; Federal, 2%

Forest—private, 3%

Urban development—private, 3%

Water—private, 1%

Other—private, 1%

Most of this area is in farms. More than one-half of the area

is cropland. Winter wheat is the principal crop. Other small

grains, grain sorghum, hay, and corn also are important crops.

Some areas along the large rivers are irrigated. The crops

grown in nonirrigated areas also are grown in irrigated areas,

but more corn and less wheat are grown in the irrigated areas.

More than one-third of the area supports native grasses grazed

by cattle.

The major soil resource concerns are water erosion,

maintenance of the content of organic matter and tilth of the

soils, and soil moisture management. The resource concerns on

pasture and rangeland are the productivity, health, and vigor of

plants and the spread of noxious and invasive species.

Conservation practices on cropland generally include

high-residue crops in the cropping system; systems of crop

residue management, such as no-till and mulch-till; a

combination of terraces and grassed waterways; contour

75—Central Loess Plains

This area (shown in fig. 75-1) is in Nebraska (90 percent) and

Kansas (10 percent). It makes up about 8,055 square miles

(20,870 square kilometers). It includes the towns of Holdrege,

Minden, Hastings, York, Seward, David City, Crete, and

Fairbury, Nebraska, and Belleville, Kansas. Interstate 80 crosses

the northeastern part of this area. Locally, much of the area

south of the Platte River in Nebraska is called the “Rainwater

Basin.”

farming; contour stripcropping; conservation crop rotations;

and nutrient management. Conservation practices on rangeland

generally include prescribed grazing, brush management,

management of upland wildlife habitat, proper distribution of

watering facilities, and control of noxious and invasive plant

species. 
of the United States 205

Physiography

This area is in the Great Plains Province of the Interior

Plains. The northern part, in Nebraska, is mostly in the High

Plains Section of the province, and the part of the area along

the Nebraska-Kansas border and in Kansas is in the Plains

Border Section. This MLRA is an area of nearly level to gently

rolling plains. Most of the stream valleys are narrow and are not

deeply incised. The major river valleys are broader, and terraces

are common. Elevation ranges from 1,650 to 1,970 feet (505 to

600 meters), increasing from east to west. Local relief is

generally 10 to 25 feet (3 to 8 meters), but it can be 100 to 165

feet (30 to 50 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Kansas (1027), 77 percent; Republican (1025), 17 percent; and

Platte (1020), 6 percent. The Platte River runs along the

northern edge of this MLRA, in Nebraska. The Little Blue

River crosses from Nebraska into the small part of this area in

Kansas.

Geology

Most of this area is mantled by loess. The present drainage

pattern cuts into the upper loess mantle and exposes the older

Loveland loess in places. Quaternary sand and gravel deposits

lie beneath the loess in Nebraska. Unconsolidated sediments lie

beneath the loess in northern Kansas. Unconsolidated sand

deposits are in the valleys along the major rivers and on the

terraces along these rivers.

Climate

The average annual precipitation in this area is 23 to 36

inches (585 to 915 millimeters). The maximum precipitation

occurs from the middle of spring to the middle of autumn. Most

of the rainfall occurs as high-intensity, convective

thunderstorms. The low winter precipitation occurs as snow.

The average annual temperature is 50 to 58 degrees F (10 to 15

degrees C), increasing from north to south. The freeze-free

period averages 195 days and ranges from 170 to 220 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 1.0%

Livestock—surface water, 0.1%; ground water, 0.4%

Irrigation—surface water, 25.4%; ground water, 66.5%

Other—surface water, 6.5%; ground water, 0.1%

The total withdrawals average 1,580 million gallons per day

(5,980 million liters per day). About 68 percent is from ground

water sources, and 32 percent is from surface water sources. The

moderate, somewhat erratic precipitation is the source of water

for grain crops, native grasses, and pasture. In the northwestern

part of the area, the Platte River provides some water for

irrigation. Reservoirs and in-stream diversions provide most of

the water used in the part of this area in Kansas. The surface

water is generally of good quality and requires minimal

treatment for most uses.

Ground water that is hard but otherwise of good quality is

abundant in the Quaternary sand and gravel in the High Plains

aquifer underlying the part of this area in Nebraska. This is one

of the most heavily used aquifers for irrigation water in

Nebraska. The median level of total dissolved solids is 350

parts per million (milligrams per liter). Much of the recharge in

this aquifer occurs from seepage beneath irrigated fields and

directly from the Platte River. About 10 percent of the wells

sampled in this aquifer exceeded the 10 parts per million

(milligrams per liter) national drinking water standard for

nitrate nitrogen. The median level of nitrogen in this aquifer is

2.4 parts per million (milligrams per liter). Ground water is

scarce in areas where shale and clay are near the surface.

Soils

The dominant soil order in this MLRA is Mollisols. The

soils in the area dominantly have a mesic soil temperature

regime, an ustic soil moisture regime, and mixed or smectitic

mineralogy. They generally are moderately deep to very deep,

moderately well drained to somewhat poorly drained, and

loamy or clayey. Haplustolls formed in residuum on uplands

(Clime series), in loess on uplands (Kenesaw series), and in

alluvium on stream terraces (Muir series). Argiustolls formed in

loess (Crete, Geary, Holder, Holdrege, and Smolan series) and

clayey sediments (Irwin and Ladysmith series) on uplands.

Argiaquolls (Butler series) formed in mixed loess and alluvium

on uplands and stream terraces. Ustifluvents (Hobbs series)

formed in alluvium on flood plains.

Biological Resources

This area supports mid and tall grasses. Big bluestem, little

bluestem, switchgrass, Indiangrass, and sideoats grama

characterize the vegetation on silty soils in the uplands. These

grasses and western wheatgrass are on bottom land and in

upland basins.

Some of the major wildlife species in this area are whitetailed deer, badger, skunk, cottontail, tree squirrel, ground

squirrel, pocket gopher, pheasant, and bobwhite quail.
206 Major Land Resource Areas

Figure 76-1: Location of MLRA 76 in Land Resource Region H.

76—Bluestem Hills

This area (shown in fig. 76-1) is in Kansas (84 percent) and

Oklahoma (16 percent). It makes up about 7,555 square miles

(19,585 square kilometers). The towns of Manhattan and El

Dorado, Kansas, and Pawhuska, Oklahoma, are in this MLRA.

The part of this area in Oklahoma lies between the towns of

Ponca City and Bartlesville. Interstates 35 and 70 cross the part

of the area in Kansas. The western edge of the Potawatomi

Indian Reservation and the Fort Riley Military Base are in the

part of the area in Kansas. Most of the Osage Indian

Reservation in Oklahoma is in this area. The area is known

as the “Flint Hills” in Kansas and the “Osage Hills” in

Oklahoma.

Physiography

Most of this area is in the Osage Plains Section of the

Central Lowland Province of the Interior Plains. The northern

end of the area is in the Dissected Till Plains Section of the

same province and division. The landscape consists of rolling

hills and cuestas formed in dissected uplands that typically

have narrow divides and narrow, steep-sided valleys where

Pennsylvanian limestone bedrock is dominant. Stream valleys

are less box-like (broader) where the dominant bedrock is shale.

Significant flood plains occur only along a few large streams.

Elevation ranges from 980 to 1,650 feet (300 to 505 meters).

Local relief is generally 10 to 25 feet (3 to 8 meters), but it can

be 100 to 165 feet (30 to 50 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Neosho-Verdigris (1107), 33 percent; Kansas (1027), 29

percent; Middle Arkansas (1103), 18 percent; ArkansasKeystone (1106), 18 percent; and Republican (1025), 2 percent.

The area has two large rivers. The Kansas River crosses the

northern part of the area, and the Arkansas River runs along the

southwestern edge. The smaller rivers that cross the area

include the Vermillion, Mill, Neosho, Cottonwood, Fall,

Verdigris, Grouse, Elk, Caney, and Bird Rivers.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 72%

Grassland—private, 18%; Federal, 1%

Forest—private, 2%

Urban development—private, 4%

Water—private, 1%

Other—private, 2%

Nearly all of this area is in farms. Almost three-fourths of the

area is cropland. Hard winter wheat and grain sorghum are the

main cash crops, but large acreages are planted to other small

grains or to hay. Corn is a major cash crop in the northern part

of the area. Most of the corn is irrigated by water from wells or

canals. About one-fifth of the area is rangeland or pasture

grazed by beef cattle.

The major soil resource concerns are water erosion,

maintenance of the content of organic matter and tilth of the

soils, surface compaction, and soil moisture management. The

resource concerns on pasture and rangeland are the

productivity, health, and vigor of plants and the spread of

noxious and invasive plant species.

Conservation practices on cropland generally include highresidue crops in the cropping system; systems of crop residue

management, such as no-till and mulch-till; a combination of

gradient terraces and grassed waterways; contour farming;

contour stripcropping; and nutrient management. Conservation

practices on rangeland generally include prescribed grazing,

brush management, management of upland wildlife habitat,

proper distribution of watering facilities, and control of

noxious and invasive plant species. 
of the United States 207

Geology

The bedrock beneath this area is primarily Pennsylvanian

and Permian shale and limestone. Chert (flint) in the limestone

beds gives rise to the local name for this area in Kansas, the

“Flint Hills.” The chert is much less erodible than the

limestone, so the soils in the area become stony as the

limestone erodes away, leaving the flint fragments. Mainly

because of the stoniness, the prairie in this area generally has

never been converted to cropland. The limestone beds beneath

part of this area in Oklahoma are of Pennsylvanian age.

Unconsolidated sand and gravel occur in river valleys and on

terraces.

Climate

The average annual precipitation in this area is 31 to 38

inches (785 to 965 millimeters). The maximum precipitation

occurs from the middle of spring through early autumn. Most of

the rainfall occurs as high-intensity, convective thunderstorms.

The annual snowfall averages 14 to 20 inches (35 to 50

centimeters). The average annual temperature is 52 to 60

degrees F (11 to 15 degrees C). The freeze-free period averages

210 days and ranges from 190 to 225 days, increasing in length

to the south.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 12.9%; ground water, 10.2%

Livestock—surface water, 15.8%; ground water, 4.5%

Irrigation—surface water, 53.9%; ground water, 2.7%

Other—surface water, 0.0%; ground water, 0.0%

The total withdrawals average 35 million gallons per day

(130 million liters per day). About 17 percent is from ground

water sources, and 83 percent is from surface water sources. The

moderate precipitation provides water for pastures and crops.

Much of the water for livestock is stored in small reservoirs and

ponds. A small area is irrigated with water from the Arkansas

River in Oklahoma. The surface water is generally of good

quality and is suitable for most uses.

Ground water is used for rural and domestic supplies and as

livestock water. In the areas of limestone, shallow wells yield

moderate quantities of good-quality water, but very little water

is available in the areas underlain by shale. Water from deep

wells is highly mineralized. Ground water from the Chase and

Council Grove aquifer along the west side of this area, in

Kansas, is very hard but is suitable for most uses. The levels of

total dissolved solids and sulfate are high in some areas but do

not limit use of the water.

Ground water is available in the unconsolidated sediments

in the valleys along the Kansas and Arkansas Rivers in the area.

The level of total dissolved solids generally is about 500 parts

per million (milligrams per liter) in the valley along the

Arkansas River and 500 to 1,000 parts per million (milligrams

per liter) in the valley along the Kansas River. The water is very

hard and requires softening if it is used for industry or domestic

purposes. As freshwater is removed, brine moving up into this

aquifer from deeper marine sediments can increase the salinity

(the level of chlorides and sulfates) of the water in the alluvial

aquifer. The water in the aquifer can be contaminated mainly

because of agricultural chemicals, irrigation return flows, and

the production of oil and gas in the area.

The Vamoosa-Ada aquifer occurs in the part of this area in

Oklahoma. It has good-quality water that is suitable for

drinking but is little used. Some parts of this aquifer have been

contaminated because of past oil and gas exploration and

production activities.

Soils

The dominant soil order in this MLRA is Mollisols. The

soils in the area dominantly have a mesic or thermic soil

temperature regime, an ustic or udic soil moisture regime, and

mixed or smectitic mineralogy. They are very shallow to very

deep, moderately well drained to somewhat excessively

drained, and generally loamy or clayey. Haplustolls (Clime,

Shidler, and Sogn series) formed in residuum on uplands.

Natrustolls (Dwight series) formed in clayey sediments on

uplands. Argiustolls formed in residuum (Benfield, Foraker,

Florence, and Labette series) and mixed colluvium and

alluvium (Tully series) on uplands. Hapludolls (Ivan and

Verdigris series) formed in alluvium on flood plains. Argiudolls

(Martin and Summit series) formed in colluvium and/or

residuum. Hapluderts (Apperson series) formed in shale

residuum.

Biological Resources

This area supports tall prairie grasses. Big bluestem,

Indiangrass, switchgrass, and little bluestem are the dominant

species. Little bluestem and big bluestem grow on shallow

soils. Very little of this area has been cultivated because of the

abundance of cherty limestone near and on the surface. Thus,

the MLRA has the last large intact areas of the tall grass

ecosystem in the United States. It is a focal area for the

preservation of this ecosystem.

Some of the major wildlife species in this area are whitetailed deer, coyote, fox, badger, beaver, raccoon, skunk, civet,

opossum, muskrat, mink, great blue heron, prairie chicken, and

bobwhite quail. The species of fish in the area include bass,

walleye, catfish, bullhead, and carp.
208 Major Land Resource Areas

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 18%

Grassland—private, 69%; Federal, 3%

Forest—private, 4%

Urban development—private, 3%

Water—private, 2%

Other—private, 1%

Nearly all of this area is in farms or ranches. Nearly threefourths of the area supports native grasses grazed by beef cattle.

Nearly one-fifth of the area, consisting mainly of the deeper

soils in valleys and on some of the uplands, is cropland. Some

winter wheat is grown as a cash crop. Other small grains, grain

sorghum, alfalfa, and other kinds of hay are the major crops.

These crops are also grown in small irrigated areas along the

Arkansas River.

The major soil resource concerns are water erosion, surface

compaction, moisture conservation, and maintenance of the

content of organic matter in the soils. Maintenance of plant

health and vigor and control of noxious and invading plants are

the major management concerns on grassland.

Conservation practices on cropland generally include

terraces, grassed waterways, grade-control structures,

conservation tillage, and nutrient and pest management.

Conservation practices on rangeland generally include brush

management, control of noxious weeds, nutrient management,

and proper grazing management. 

Figure 77A-1: Location of MLRA 77A in Land Resource Region H.

77A—Southern High Plains, Northern

Part

This area (shown in fig. 77A-1) is in northwestern Texas (44

percent), the Oklahoma Panhandle (41 percent), southwestern

Kansas (14 percent), and southeastern Colorado (1 percent). It

makes up about 10,005 square miles (25,930 square

kilometers). The towns of Dumas, Dalhart, Spearman, and

Perryton, Texas, are in the southern part of this area. The towns

of Elkhart, Hugoton, and Liberal, Kansas, are in the northern

part. The towns of Boise City, Guymon, and Hooker, Oklahoma,

are in the central part. The area has numerous U.S. highways but

no interstate highways. Most of the Rita Blanca National

Grassland is in the western part of this area, and more than half

of the Cimarron National Grassland is in the northern part, in

Kansas.

Physiography

This area is in the High Plains Section of the Great Plains

Province of the Interior Plains. It is characterized by extensive

areas of open plains on an elevated plateau. Numerous draws

with moderate to very steep slopes and narrow flood plains are

incised into the plateau and generally trend from southwest to

northeast. The area has a number of interspersed playa basins

ranging from 5 to more than 100 acres (2 to 40 hectares) in size.

Elevation is 4,500 feet (1,370 meters) in the western part of the

area and gradually decreases to 2,900 feet (885 meters) in the

east-northeast part. The topographical relief is dominated by

nearly level and very gentle slopes.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

North Canadian (1110), 74 percent; Upper Cimarron (1104), 22

percent; and Lower Canadian (1109), 4 percent. The area is

bounded by the Cimarron River to the north, the Canadian

Breaks to the south and east, and Rita Blanca Creek to the west.

Geology

The surface of this area is covered primarily by eolian loess

and sand deposits of Holocene age. These deposits are
of the United States 209

underlain by sand and gravel of the Ogallala Formation of

Miocene-Pliocene age. Unconsolidated sand and gravel

deposits occur in the larger river valleys.

Climate

The average annual precipitation in this area is 15 to 22

inches (380 to 560 millimeters), fluctuating widely from year to

year. Most of the rainfall occurs as high-intensity, convective

thunderstorms during spring and fall. Most of the winter

precipitation occurs as snow. The average annual temperature is

54 to 58 degrees F (12 to 14 degrees C). The freeze-free period

averages 200 days and ranges from 185 to 215 days, increasing

in length from north to south.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.3%; ground water, 1.0%

Livestock—surface water, 0.1%; ground water, 0.5%

Irrigation—surface water, 8.0%; ground water, 89.8%

Other—surface water, 0.0%; ground water, 0.3%

The total withdrawals average 1,445 million gallons per day

(5,470 million liters per day). About 92 percent is from ground

water sources, and 8 percent is from surface water sources. The

moderately low, erratic precipitation is the source of water for

dry-farmed crops and for range. The flow of the Canadian River

and its tributaries fluctuates widely from year to year, and the

water in these rivers is little used for irrigation. The water is

slightly saline because of natural sources of salts and because

of irrigation return flows from cropland irrigated with ground

water.

Sand and gravel in the High Plains or Ogallala aquifer yield

an abundance of ground water for irrigation and public supply.

The water is very hard and has a median level of total dissolved

solids that increases from 340 to 419 parts per million

(milligrams per liter) from Kansas to Texas. The water table has

dropped from historic levels because of the number of highyield wells tapping this aquifer. In some areas the declining

water table and rising energy costs have resulted in conversion

from previously irrigated cropland to dry-farmed cropland.

Alluvial and terrace deposits provide water for irrigation and

domestic use in the part of this area in Oklahoma. This water is

very similar in quality to the water in the High Plains aquifer,

but it has a slightly higher median level of total dissolved

solids.

Soils

The dominant soil orders in this area are Alfisols and

Mollisols. The soils in the area dominantly have a mesic soil

temperature regime, an ustic soil moisture regime, and mixed

mineralogy. They generally are very deep, well drained, and

loamy. Paleustolls (Dumas, Gruver, and Sherm series) and

Argiustolls (Belfon, Darrouzett, Hugoton, and Zella series)

formed in loess on plains. Paleustolls formed in loamy material

(Sunray and Texline series) and loess (Dallam and Dalhart

series) on plains and in sandy eolian material on sandhills (Eva

series). Haplustalfs (Bigbow and Canina series) formed in loess

on plains. Calciustolls (Conlen series) formed in loess on ridges

and side slopes adjacent to drainageways. Very shallow and

shallow Calciustolls (Plack series) have a petrocalcic horizon

and formed in loamy material in sloping areas. Haplusterts

(Hansford and Lautz series) formed in lacustrine deposits on

playa floors.

Biological Resources

This area dominantly supports short or mid prairie grasses.

Nearly level plains dominated by fine textured soils are

characterized by a plant community of short grasses with a few

mid grasses. Blue grama and buffalograss are common; blue

grama is the dominant species. On very gently sloping and

gently sloping plains dominated by moderately fine textured

soils, the plant community is characterized by short and mid

grasses and sideoats grama is the dominant species. In areas of

sandy soils on gently to moderately sloping plains and

sandhills, the plant community is characterized by tall grasses.

Little bluestem and sand bluestem make up nearly half of these

tall grasses. The woody shrubs on sandy soils include sand sage

and shin oak.

Some of the major wildlife species in this area are mule deer,

white-tailed deer, coyote, badger, raccoon, skunk, jackrabbit,

cottontail, turkey, pheasant, Canada goose, scaled quail,

bobwhite quail, and mourning dove. The species of fish in the

area include bass, bluegill, catfish, and bullhead.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 60%

Grassland—private, 32%; Federal, 5%

Urban development—private, 2%

Other—private, 1%

Farms and ranches make up nearly all of this area. About

three-fifths of the area is cropland, which is used mainly for

wheat, grain sorghum, corn, and soybeans. Almost two-fifths of

the area is range or improved pasture. Confined animal-feeding

operations, primarily for beef cattle and swine, are

economically important in the area. In some areas beef cattle

graze small grain pastures throughout the winter.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and

productivity of the soils, and management of soil moisture.

Conservation practices on cropland generally include systems
210 Major Land Resource Areas

of crop residue management (especially no-till systems that

reduce the need for tillage), cover crops, windbreaks,

vegetative wind barriers, wind stripcropping, and nutrient

management. The dominant conservation practice on rangeland

is prescribed grazing. Generally, cultural treatments are not

used to increase forage production on the rangeland in this

area. Haying commonly provides supplemental feed during the

long winters. 

Figure 77B-1: Location of MLRA 77B in Land Resource Region H.

77B—Southern High Plains,

Northwestern Part

This area (shown in fig. 77B-1) is in northeastern New

Mexico (64 percent), northwestern Texas (35 percent), and the

Oklahoma Panhandle (1 percent). It makes up about 3,930

square miles (10,185 square kilometers). The towns of Perico,

Corlena, Middle Water, and Ware, Texas, and Amistad, Clayton,

Seneca, and Stead, New Mexico, are in this MLRA. U.S.

Highways 56, 64, and 87 cross this area. The Kiowa and Rita

Blanca National Grasslands are in the area.

Physiography

The eastern half of this area is in the High Plains Section of

the Great Plains Province of the Interior Plains. The western half

is in the Raton Section of the same province and division. This

MLRA is characterized by extensive areas of open plains on an

elevated plateau. Moderately steep escarpments border the

plateau to the west. A few draws with moderate to steep slopes

and narrow flood plains are incised into the plateau and

generally trend from northwest to southeast. Elevation is 5,200

feet (1,585 meters) in the northwestern part of the area and

gradually decreases to 3,800 feet (1,160 meters) in the

southeastern part. The topographical relief is characterized by

nearly level to gently sloping plains and gently sloping to

strongly sloping sandhills.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Lower Canadian (1109), 60 percent; Upper Canadian (1108),

26 percent; North Canadian (1110), 12 percent; and Upper

Cimarron (1104), 2 percent. The area is bounded by Rita

Blanca Creek to the north and east and the Canadian Breaks to

the south.

Geology

The surface of this area is covered primarily by eolian

sediments of the Blackwater Draw Formation and sandy eolian

deposits of Holocene age. These deposits are underlain by sand

and gravel of the Ogallala Formation of Miocene-Pliocene age.

Unconsolidated sand and gravel deposits occur in the larger

river valleys.

Climate

The average annual precipitation in this area is 14 to 18

inches (355 to 455 millimeters), fluctuating widely from year to

year. Most of the rainfall occurs as high-intensity, convective

thunderstorms during spring and fall. Most of the winter

precipitation occurs as snow. The average annual temperature is

49 to 56 degrees F (10 to 14 degrees C). The freeze-free period

averages 185 days and ranges from 165 to 205 days, increasing

in length from north to south.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 0.1%; ground water, 0.1%

Irrigation—surface water, 31.7%; ground water, 68.1%

Other—surface water, 0.0%; ground water, 0.0%
of the United States 211

The total withdrawals average 360 million gallons per day

(1,360 million liters per day). About 68 percent is from ground

water sources, and 32 percent is from surface water sources. The

moderately low, erratic precipitation is the source of water for

dry-farmed crops and for range. The flow in the tributaries of

the Canadian River fluctuates widely from year to year, and the

water in these tributaries is little used for irrigation. Reservoirs

provide some surface water for irrigation. Most of the surface

water in the area is slightly saline because of natural sources of

salts and because of irrigation return flows from cropland

irrigated with ground water.

Sand and gravel in the High Plains or Ogallala aquifer yield

an abundance of ground water for irrigation, but the water table

generally is gradually declining. This aquifer is called the

Eastern New Mexico Basin Fill aquifer in the part of this area in

New Mexico. The High Plains aquifer is not actually a basin fill

deposit, but its water is so similar in quality to the water in

other basin fill aquifers in New Mexico that it is lumped with

them. The water is very hard and has a median level of total

dissolved solids of 400 to 500 parts per million (milligrams per

liter).

Soils

The dominant soil order in this area is Alfisols. The soils in

the area dominantly have a mesic soil temperature regime, an

ustic soil moisture regime, and mixed mineralogy. They

generally are very deep, well drained, and loamy or sandy.

Paleustalfs formed in loamy sediments on plains (Dallam,

Perico, Rickmore, and Spurlock series) and in sandy eolian

material on dunes and hummocks (Vingo series).

Torripsamments (Valent series) formed on steep dunes.

Biological Resources

This area dominantly supports mid and tall prairie grasses.

Nearly level to sloping plains and sandhills dominated by

moderately fine textured to moderately coarse textured soils are

characterized by a mixture of mid and tall grasses and a lesser

amount of short grasses. On loamy soils, mid grasses are

dominant and sideoats grama is the dominant species. Woody

shrubs, particularly yucca, catclaw, and sand sage, make up 5

percent or less of the plant community. On sandy soils, nearly

half of the grasses in the plant community are tall grasses, such

as little bluestem and sand bluestem. Woody shrubs,

specifically sand sage, shin oak, and skunkbush, make up 20 to

30 percent of the plant community.

Some of the major wildlife species in this area are mule deer,

white-tailed deer, coyote, badger, raccoon, skunk, jackrabbit,

cottontail, turkey, pheasant, Canada goose, scaled quail,

bobwhite quail, and mourning dove. The species of fish in the

area include bass, bluegill, catfish, and bullhead.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 30%

Grassland—private, 63%; Federal, 5%

Urban development—private, 1%

Other—private, 1%

Rangeland and cropland make up nearly all of this MLRA.

About two-thirds of the area is used for grazing, and the beef

cattle industry is economically important in the area. In some

areas beef cattle graze small grain pastures throughout the

winter. Almost one-third of the area is cropland. Most of the

crops are irrigated. Corn is the principal irrigated crop. Wheat

and grain sorghum also are grown in irrigated areas.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and

productivity of the soils, and management of soil moisture.

Conservation practices on cropland generally include systems

of crop residue management (especially no-till systems that

reduce the need for tillage), cover crops, windbreaks, vegetative

wind barriers, wind stripcropping, and nutrient management.

The most important conservation practice on rangeland is

prescribed grazing. Generally, cultural treatments are not used

to increase forage production on the rangeland in this area.

Haying commonly provides supplemental feed during the long

winters. 

77C—Southern High Plains, Southern

Part

This area (shown in fig. 77C-1) is in western Texas (90

percent) and eastern New Mexico (10 percent). It makes up

about 20,955 square miles (54,300 square kilometers). The

cities of Amarillo and Lubbock, Texas, and the towns of

Brownfield, Floydada, Hereford, Lamesa, Levelland, Littlefield,

Muleshoe, and Plainview, Texas, and Clovis, Grady, and

Portales, New Mexico, are in this MLRA. Interstate 40 crosses

the northern end of this area, and Interstate 27 connects

Amarillo and Lubbock, Texas. The Cannon Air Force Base is in

the part of the area in New Mexico, and the Reese and Webb Air

Force Bases are in the part in Texas. The area has a number of

national wildlife refuges.

Physiography

This area is in the High Plains Section of the Great Plains

Province of the Interior Plains. It is characterized by extensive

areas of open plains on a distinct elevated plateau. The area is
212 Major Land Resource Areas

Figure 77C-1: Location of MLRA 77C in Land Resource Region H.

bounded by the Canadian Breaks to the north, steep

escarpments overlooking the Rolling Red Plains to the east,

and the Edwards Plateau to the south. To the west, the plains

grade indiscernibly into the Southern High Plains,

Southwestern Part (MLRA 77D). A few draws with moderate to

steep slopes and very narrow flood plains are incised into the

plateau and trend generally from northwest to southeast.

Numerous playa basins ranging from 5 to 160 acres (2 to 65

hectares) in size dot the landscape. Elevation is 4,600 feet

(1,400 meters) in the northwestern part of the area and

gradually decreases to 2,600 feet (795 meters) in the

southeastern part. The topographical relief is dominated by

nearly level and very gentle slopes.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Brazos Headwaters (1205), 44 percent; Red Headwaters (1112),

28 percent; Upper Colorado (1208), 22 percent; Red-Washita

(1113), 4 percent; and Lower Canadian (1109), 2 percent. A few

streams in the northern part of this area drain to the north into

the Canadian River, which is outside this area. Many headwater

streams of the Red River are in this area, and some of the

headwaters of the Brazos and Colorado Rivers are in the

southern part of the area.

Geology

The surface of this area is covered primarily by eolian

deposits in the Blackwater Draw Formation of Pleistocene age.

Lacustrine deposits of dolomite with interbedded clastic

sediments are both laterally extensive where they are of

Pliocene age (Blanco Formation) and more local where they are

of Pleistocene age (Tule, Double Lakes, and Tahoka

Formations). Locally, draws inset alluvial deposits in the

Ogallala Formation of Miocene-Pliocene age.

Climate

The average annual precipitation in this area is 16 to 22

inches (405 to 560 millimeters), fluctuating widely from year to

year. Most of the rainfall occurs as high-intensity, convective

thunderstorms during late spring and early fall. The average

annual temperature is 55 to 63 degrees F (13 to 17 degrees C).

The freeze-free period averages 225 days and ranges from 195

to 255 days, increasing in length from north to south.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 1.1%; ground water, 1.2%

Livestock—surface water, 0.1%; ground water, 0.2%

Irrigation—surface water, 20.4%; ground water, 76.1%

Other—surface water, 0.7%; ground water, 0.3%

The total withdrawals average 3,800 million gallons per day

(14,385 million liters per day). About 78 percent is from ground

water sources, and 22 percent is from surface water sources. The

moderately low, erratic precipitation is the source of water for

dry-farmed crops and for range. Few perennial streams are in the

area. Their flow fluctuates widely from year to year, and their

water is little used for irrigation. The headwaters of both the

Brazos and Colorado Rivers receive high salt loads from

natural sources downstream from this area.

Irrigation water is obtained from wells in the High Plains or

Ogallala aquifer, but withdrawals exceed recharge and the water

table is gradually declining. In some areas the declining water

table and increasing energy costs have resulted in the

conversion of previously irrigated cropland to dry-farmed

cropland. The High Plains aquifer is called the Eastern New

Mexico Basin Fill aquifer in the part of this area in New

Mexico. The High Plains aquifer is not actually a basin fill

deposit, but its water is so similar in quality to that of other
of the United States 213

basin fill aquifers in New Mexico that it is lumped with them.

The ground water in this area is very hard and has a median

level of total dissolved solids of 400 to 500 parts per million

(milligrams per liter).

Soils

The dominant soil orders in this MLRA are Alfisols,

Inceptisols, Mollisols, and Vertisols. The soils in the area

dominantly have a thermic soil temperature regime, an ustic

soil moisture regime, and mixed mineralogy. They generally are

moderately deep to very deep, well drained, and clayey, loamy,

or sandy.

Paleustalfs (Amarillo and Arvana series) formed in loamy

eolian sediments (Amarillo series) and sandy eolian sediments

(Brownfield, Patricia, and Plains series) on nearly level to

gently sloping plains. They also formed in loamy eolian

sediments on nearly level to very gently sloping plains and the

side slopes of drainageways and playa basins (Posey series).

Haplustalfs formed in loamy eolian sediments (Tokio series)

and sandy eolian sediments (Yoakran series) on nearly level to

gently sloping plains. Calciustepts formed in loamy eolian

sediments on nearly level to gently sloping plains or playa

steps within playa basins (Arch and Gomez series), on dunes on

the margins of playa basins (Drake series), and on plains and

the side slopes of drainageways and playa basins (Midessa

series). Ustipsamments (Nutivoli series) formed in sandy eolian

sediments on dunes. Haplusterts (Chapel, Lazbuddie, Lockney,

McLean, Ranco, Randall, and Sparenberg series) formed in

clayey lacustrine deposits on playa floors within playa basins.

Paleustolls (Acuff, Friona, Olton, Pantex, and Pullman series)

formed in loamy and clayey eolian sediments on plains. They

also formed in mixed alluvium and eolian sediments (Estacado

series) and in loamy eolian sediments (Mansker series) on

plains and shoulder slopes along drainageways and in playa

basins. Calciustolls formed in loamy eolian sediments (Pep

series) and in lacustrine deposits (Portales series) on plains and

the side slopes of drainageways and playa basins.

Biological Resources

The northeastern part of this area supports dominantly short

and mid prairie grasses and sparse trees and shrubs. Fine

textured soils on broad, nearly level plains support a plant

community of short grasses and a few mid grasses. The most

common species are blue grama and buffalograss; blue grama is

dominant. In areas of moderately fine textured soils on very

gently to moderately sloping plains, the plant community

consists of mixed short and mid grasses and sideoats grama is

the dominant species.

The southwestern part of this area primarily supports mixed

prairie grasses and sparse trees and shrubs. Moderately fine

textured and moderately coarse textured soils on nearly level to

gently sloping plains and gently to strongly sloping sandhills

are characterized by a mixture of tall and mid grasses and lesser

amounts of short grasses. On loamy soils, mid grasses tend to

dominate and sideoats grama is the dominant species. Woody

shrubs, particularly yucca, catclaw, and sand sage, make up 5

percent or less of the plant community. On sandy soils, nearly

half of the grasses in the plant community are tall grasses, such

as little bluestem and sand bluestem. Woody shrubs,

specifically sand sage, shin oak, and skunkbush, make up 20 to

30 percent of the plant community on the sandy soils.

Some of the major wildlife species in this area are mule deer,

white-tailed deer, coyote, badger, raccoon, skunk, jackrabbit,

cottontail, turkey, pheasant, Canada goose, scaled quail,

bobwhite quail, and mourning dove. The species of fish in the

area include bass, bluegill, catfish, and bullhead.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 73%

Grassland—private, 23%

Urban development—private, 3%

Other—private, 1%

Farmland makes up nearly all of this area. It is mainly

cropland. A lesser percentage of the farmland consists of

rangeland, improved pasture, and wildlife habitat, primarily in

the southern and western parts of the area. The principal crops

are wheat, grain sorghum, and corn in the northern part of the

area and cotton, grain sorghum, and peanuts in the southern

part. Minor crops include soybeans, sunflowers, alfalfa hay, and

forage sorghum. Confined animal-feeding operations, primarily

for beef cattle, are economically important in the area. In some

areas beef cattle graze small grain pastures throughout the

winter.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and

productivity of the soils, and management of soil moisture.

Conservation practices on cropland generally include systems

of crop residue management (especially no-till systems that

reduce the need for tillage), cover crops, windbreaks, vegetative

wind barriers, wind stripcropping, and nutrient management.

The most important conservation practice on rangeland is

prescribed grazing. Generally, cultural treatments are not used

to increase forage production on the rangeland in this area.

Haying commonly provides supplemental feed during the long

winters. 
214 Major Land Resource Areas

Figure 77D-1: Location of MLRA 77D in Land Resource Region H.

77D—Southern High Plains,

Southwestern Part

This area (shown in fig. 77D-1) is in southeastern New

Mexico (52 percent) and western Texas (48 percent). It makes

up about 9,905 square miles (25,665 square kilometers). The

towns of Crossroads, House, Lovington, McAlister, Melrose,

and Tatum, New Mexico, and the cities or towns of Midland,

Odessa, Andrews, and Gardendale, Texas, are in this MLRA.

Interstate 20 crosses the southern tip of this area, in Texas. The

Melrose Bombing Range Military Reservation is in the north

end of this area, in New Mexico.

Physiography

This area is in the High Plains Section of the Great Plains

Province of the Interior Plains. It is characterized by large areas

of open plains on an elevated plateau. The area is bounded by

steep escarpments to the west and by the Canadian Breaks to

the north. The Pecos Valley lies below the escarpments. A small

number of draws with moderate to steep slopes and very narrow

flood plains are incised into the plateau and trend generally

from northwest to southeast. The area has some interspersed

playa basins ranging from 5 to more than 100 acres (2 to 40

hectares) in size. Elevation is 5,200 feet (1,585 meters) in the

northwestern part of the area and gradually decreases to 2,800

feet (855 meters) in the southeastern part. The topographical

relief is characterized by nearly level to gently sloping plains

and gently sloping to strongly sloping sandhills.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Upper Colorado (1208), 72 percent; Brazos Headwaters (1205),

13 percent; Upper Pecos (1306), 10 percent; and Lower Pecos

(1307), 5 percent. Some headwater streams of the Colorado and

Concho Rivers cross the part of this area in Texas. No large

rivers are in the part in New Mexico. A few headwater

tributaries of the Brazos River occur in the northern end of the

area.

Geology

The surface of this area is covered primarily by eolian

sediments in the Blackwater Draw Formation of Pleistocene age

and sand sheets and dunes of Quaternary age. It is underlain by

sand and gravel of the Miocene-Pliocene Ogallala Formation.

Thin alluvial deposits are in the few large river valleys in the

area.

Climate

The average annual precipitation in this area is 13 to 19

inches (330 to 485 millimeters), fluctuating widely from year to

year. Most of the rainfall occurs as high-intensity, convective

thunderstorms during spring and fall. For the most part, winter

precipitation occurs as light snow and rainfall. The average

annual temperature is 55 to 64 degrees F (13 to 18 degrees C).

The freeze-free period averages 220 days and ranges from 190

to 250 days, increasing in length from north to south.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 2.2%; ground water, 3.0%

Livestock—surface water, 0.1%; ground water, 0.3%

Irrigation—surface water, 25.7%; ground water, 52.2%

Other—surface water, 11.0%; ground water, 5.5%

The total withdrawals average 1,090 million gallons per day

(4,125 million liters per day). About 61 percent is from ground

water sources, and 39 percent is from surface water sources. The

headwaters of the Colorado and Concho Rivers receive high
of the United States 215

salt loads from natural sources in this area. These rivers flow

into reservoirs to the east of this area, where the salinity levels

are diluted by fresher runoff, which makes the water usable.

Irrigation water is obtained from wells in the High Plains or

Ogallala aquifer, but withdrawals exceed recharge and the water

table is gradually declining. Some areas that formerly were

irrigated are now dry-farmed. The High Plains aquifer is called

the Eastern New Mexico Basin Fill aquifer in the part of this

area in New Mexico. The High Plains aquifer is not actually a

basin fill deposit, but its water is so similar in quality to the

water in other basin fill aquifers in New Mexico that it is

lumped with them. The ground water in this area is very hard

and has a median level of total dissolved solids of 400 to 500

parts per million (milligrams per liter).

Soils

The dominant soil orders in this MLRA are Aridisols and

Entisols. The soils in the area dominantly have a thermic soil

temperature regime, an aridic soil moisture regime, and mixed

or siliceous mineralogy. They are very shallow to very deep,

well drained, and generally loamy or sandy. Paleargids (Arizer

and Sparks series) formed in alluvium on plains. Haplargids

(Spantara and Triomas series) formed in sandy eolian and

alluvial deposits on plains. Calciargids (Amarose series) formed

in loamy eolian material on plains. Petrocalcids (Blakeney,

Conger, Douro, and Kimbrough series) formed in loamy

material on plains, divides, and ridges. Torripsamments

(Penwell series) and Ustipsamments (Milsand series) formed in

sandy eolian deposits on plains and dunes. Endoaquepts (Grier

series) formed in alluvium on playa steps within playa basins.

Biological Resources

The northeastern part of this area dominantly supports short

and mid prairie grasses. Broad, nearly level plains dominated

by fine textured soils are characterized by a plant community of

short grasses with a few mid grasses. The most common species

are blue grama and buffalograss; blue grama is dominant. In

areas of moderately fine textured soils on very gently sloping

to moderately sloping plains, the plant community is

characterized by a mixture of short and mid grasses and

sideoats grama is the dominant species.

The southwestern part of this area dominantly supports

mixed prairie grasses. This part of the area is on nearly level to

gently sloping plains and gently sloping to strongly sloping

sandhills. The moderately fine textured and moderately coarse

textured soils are characterized by a mixture of mid and tall

grasses and lesser amounts of short grasses. On loamy soils, mid

grasses tend to dominate and sideoats grama is the dominant

species.

Woody shrubs, particularly yucca, catclaw, and sand sage,

make up 5 percent or less of the plant community. On sandy

soils, nearly half of the grasses in the plant community are tall

grasses, such as little bluestem and sand bluestem. Woody

shrubs, specifically sand sage, shin oak, and skunkbush, make

up 20 to 30 percent of the plant community on the sandy soils.

Some of the major wildlife species in this area are mule deer,

white-tailed deer, coyote, badger, raccoon, skunk, jackrabbit,

cottontail, turkey, pheasant, Canada goose, scaled quail,

bobwhite quail, and mourning dove. The species of fish in the

area include bass, bluegill, catfish, and bullhead.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 22%

Grassland—private, 72%; Federal, 1%

Urban development—private, 4%

Other—private, 1%

Farms and ranches make up nearly all of this area. Almost

three-fourths of the area is rangeland. The beef cattle industry is

economically important in the area. In some areas beef cattle

graze small grain pastures throughout the winter. Almost onefourth of the area is cropland. Nearly two-thirds of the cropland

is irrigated. Cotton, wheat, grain sorghum, and alfalfa hay are

the principal crops.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and

productivity of the soils, and management of soil moisture.

Conservation practices on cropland generally include systems

of crop residue management (especially no-till systems that

reduce the need for tillage), cover crops, windbreaks, vegetative

wind barriers, wind stripcropping, and nutrient management.

The most important conservation practice on rangeland is

prescribed grazing. Generally, cultural treatments are not used

to increase forage production on the rangeland in this area.

Haying commonly provides supplemental feed during the long

winters. 

77E—Southern High Plains, Breaks

This area (shown in fig. 77E-1) is in western Texas (69

percent), northwestern Oklahoma (21 percent), and

southwestern Kansas (10 percent). It makes up 10,320 square

miles (26,735 square kilometers). It includes the towns of

Borger, Channing, Follett, Fritch, and Stinnett, Texas; Fargo,

Beaver, Laverne, Shattuck, and Slapout, Oklahoma; and Meade,

Kansas. Numerous U.S. highways cross this area. The

McClellan Creek National Grassland, Alibates Flint Quarries

National Monument, and Lake Meredith National Recreational

Area are in this MLRA.
216 Major Land Resource Areas

Figure 77E-1: Location of MLRA 77E in Land Resource Region H.

Physiography

Most of this area is in the High Plains Section of the Great

Plains Province of the Interior Plains. The northeast quarter of

the area is in the Plains Border Section of the same province

and division. This MLRA is characterized by very steep

escarpments, very gently sloping to moderately sloping plains,

strongly sloping hills and ridges, and integrated drainage

networks along the Canadian and Beaver Rivers. The area has

undulating to hilly topography and well developed, dendritic

drainage systems. Elevation ranges from 2,200 feet (670 meters)

in the southeastern part of the area to 4,800 feet (1,465 meters)

in the northwestern part.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Lower Canadian (1109), 43 percent; North Canadian (1110), 28

percent; Upper Cimarron (1104), 13 percent; Red Headwaters

(1112), 12 percent; and Red-Washita (1113), 4 percent. The

Canadian, Beaver, and Cimarron Rivers drain this area.

Geology

The surface of this area is covered primarily by loamy and

sandy sediments of the Ogallala Formation of MiocenePliocene age. Unconsolidated sand and gravel deposits occur in

the larger river valleys.

Climate

The average annual precipitation in this area is 16 to 25

inches (405 to 635 millimeters), fluctuating widely from year to

year. Most of the rainfall occurs as high-intensity, convective

thunderstorms during spring and fall. Winter precipitation

occurs mainly as snow. The average annual temperature is 55 to

60 degrees F (13 to 16 degrees C). The freeze-free period

averages 215 days and ranges from 195 to 235 days, increasing

in length from north to south.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 3.1%; ground water, 4.3%

Livestock—surface water, 0.7%; ground water, 1.6%

Irrigation—surface water, 20.2%; ground water, 67.7%

Other—surface water, 1.2%; ground water, 1.2%

The total withdrawals average 420 million gallons per day

(1,590 million liters per day). About 75 percent is from ground

water sources, and 25 percent is from surface water sources. The

moderately low, erratic precipitation is the source of water for

dry-farmed crops and for range. The flow in the Canadian River

and its tributaries fluctuates widely from year to year, and the

water in these rivers is little used for irrigation. Reservoirs

provide some surface water for irrigation and for municipal and

industrial uses. A large reservoir on the Canadian River, Lake

Meredith, provides water for municipal and industrial uses in

Amarillo. Also, it provides water to cities in MLRAs to the

south via the Canadian River Aqueduct. Most of the surface

water in the area is slightly saline because of natural sources of

salts and because of irrigation return flows from cropland

irrigated with ground water.

Sand and gravel in the High Plains or Ogallala aquifer yield

an abundance of ground water for irrigation and public supply.

The water is very hard and has a median level of total dissolved

solids that increases from 340 to 419 parts per million

(milligrams per liter) from Kansas to Texas. The water table has

dropped from historic levels because of the number of highyield wells tapping this aquifer. Alluvial and terrace deposits in

Oklahoma provide water for irrigation and domestic use in this

area. This water is very similar in quality to the water in the

High Plains aquifer, but it has a slightly higher median level of

total dissolved solids.
of the United States 217

Soils

The dominant soil orders in this MLRA are Alfisols,

Inceptisols, and Mollisols. The soils in the area dominantly

have a thermic soil temperature regime, an ustic soil moisture

regime, and mixed or carbonatic mineralogy. They are shallow

to very deep, well drained, and generally loamy or sandy.

Argiustolls (Alibates series), Paleustolls (Manson series),

Paleustalfs (Plemons series), and Haplustalfs (Ady series)

formed in loamy sediments on plains. Argiustolls also formed in

old alluvium on plains (Abbie and Irene series) and in loamy

material on stream terraces (Texroy series). Haplustolls formed

in alluvium on flood plains (Bippus and Sprone series) and in

mixed alluvium and colluvium on backslopes and footslopes

on escarpments and hillslopes (Paloduro series). Calciustolls

formed in sandy and gravelly old alluvium on knobs and

hillslopes (Tascosa series), in older loamy alluvium on

hillslopes (Mansic and Oklark series), and in weathered caliche

on plains (Laverne series). Haplustepts formed in alluvium on

hillslopes (Berda and Mobeetie series) and in coarse-textured

sediments on flood plains (Guadalupe series). Calciustepts

(Veal series) formed in mixed alluvium and colluvium on

backslopes and footslopes on escarpments and hillslopes.

Haplocalcids (Potter series) formed in weathered caliche on

hills, ridges, and escarpments. Ustipsamments (Jester and Likes

series) formed in wind-reworked sandy alluvium on dunes.

Biological Resources

This area supports mixed prairie grasses and a lesser amount

of woody species, including yucca, pricklypear, sand

sagebrush, winterfat, and hackberry. Cottonwood and western

soapberry are along major stream channels. On very gently to

moderately sloping plains dominated by fine textured soils, the

plant community consists of short grasses and a few mid

grasses. The most common species are blue grama and

buffalograss, and blue grama is the dominant species. Fine

textured to coarse textured soils on strongly sloping hills,

ridges, or scarp slopes support a mixture of tall and mid grasses

and a lesser amount of short grasses. In strongly sloping areas of

loamy, calcareous soils, mid grasses tend to dominate and

sideoats grama is the dominant species. Woody shrubs,

particularly yucca, catclaw, and sand sage, make up a minor

percentage of the plant community. On sandy soils, nearly half

of the grasses in the plant community are tall grasses, such as

little bluestem and sand bluestem. Woody shrubs, specifically

sand sage, shin oak, and skunkbush, make up about one-fourth

of the plant community on the sandy soils.

Some of the major wildlife species in this area are mule deer,

white-tailed deer, coyote, badger, raccoon, skunk, jackrabbit,

cottontail, turkey, pheasant, Canada goose, scaled quail,

bobwhite quail, and mourning dove. The species of fish in the

area include bass, bluegill, catfish, and bullhead.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 14%

Grassland—private, 82%; Federal, 1%

Urban development—private, 2%

Water—private, 1%

Farms and ranches make up nearly all of this area. Most of

the area is used for ranching, and the beef cattle industry is

economically important in the area. In some areas beef cattle

graze small grain pastures throughout the winter. The cropland

in this MLRA is primarily in the northeastern part of the area.

Wheat, grain sorghum, and hay are the principal crops. The

crops are grown mainly on nonirrigated land, but a small

percentage of the cropland is irrigated.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and

productivity of the soils, and management of soil moisture.

Conservation practices on cropland generally include systems

of crop residue management (especially no-till systems that

reduce the need for tillage), cover crops, windbreaks, vegetative

wind barriers, wind stripcropping, and nutrient management.

The most important conservation practice on rangeland is

prescribed grazing. Generally, cultural treatments are not used

to increase forage production on the rangeland in this area.

Haying commonly provides supplemental feed during the long

winters. 

78A—Rolling Limestone Prairie

This area is in north-central Texas (fig. 78A-1). It makes up

about 4,750 square miles (12,310 square kilometers). The towns

of Throckmorton, Albany, Baird, Coleman, and Paint Rock are

in this area. Interstate 20 cuts through the middle of the area.

Physiography

The northern part of this area is in the Osage Plains Section

of the Central Lowland Province of the Interior Plains. The

southern part is in the Central Texas Section of the Great Plains

Province of the Interior Plains. This MLRA is on a moderately

dissected, rolling plain with prominent ridges and valleys and

stream terraces associated with incised river systems. The

rolling landscape developed over interbedded limestones and

shales. Limestone outcrops form escarpments and cuestas, and

limestone surface fragments cover colluvium on the adjacent

side slopes. Very deep, clayey soils are common in the valleys,

most of which are underlain by shale. Elevation ranges from

2,280 feet (695 meters) in the southwestern part of the area to

1,220 feet (370 meters) in the northeastern part. Maximum local
218 Major Land Resource Areas

Figure 78A-1: Location of MLRA 78A in Land Resource Region H.

relief is about 165 feet (50 meters), and the average local relief

is about 15 feet (5 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Middle Brazos (1206), 53 percent; Lower Colorado-San

Bernard Coastal (1209), 46 percent; and Red-Washita (1113), 1

percent. Tributaries of the Brazos River are in the northern end

of this area, and the Colorado River cuts across the southern

end.

Geology

This area is underlain by interbedded light gray and white

limestones and gray shales of Permian age. Geologic erosion

has produced a subdued, terraced landscape. Prominent

limestone scarps that are 15 to 85 feet (5 to 25 meters) high are

common throughout the area. Stones and boulders are

embedded in soils that formed on colluvial slopes below

fractured limestone outcrops. Sandy and loamy stream terrace

deposits are associated with streams that generally flow from

northwest to southeast. Erosional remnants of older stream

terraces are on uplands. Limestone and caliche quarries provide

road material in this area. Oil and gas production is important

in some areas.

Climate

The average annual precipitation in this area is 23 to 29

inches (585 to 735 millimeters). Most of the rainfall occurs as

convective thunderstorms during the growing season.

Precipitation in winter occurs as snow. The average annual

snowfall is about 4 inches (10 centimeters). The average annual

temperature is 63 to 66 degrees F (17 to 19 degrees C). The

freeze-free period averages 250 days and ranges from 240 to

265 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 4.6%; ground water, 3.1%

Livestock—surface water, 2.8%; ground water, 0.7%

Irrigation—surface water, 67.8%; ground water, 18.5%

Other—surface water, 1.2%; ground water, 1.2%

The total withdrawals average 80 million gallons per day

(300 million liters per day). About 24 percent is from ground

water sources, and 76 percent is from surface water sources. The

moderate, somewhat erratic precipitation provides water for

range and crops. Small ponds on individual farms provide water

for livestock. Some of the larger ponds on individual farms are

used for flood control, recreation, irrigation water, or water for

livestock. A few large ponds and reservoirs provide municipal

water and irrigation water. The Colorado River and tributaries

of the Brazos River are potential sources of water for irrigation.

This river water is typically saline because of contamination by

human activities and by natural sources of salts.

The Trinity Group aquifer (limestone) underlies part of the

southern half of this MLRA. The median level of total

dissolved solids in the water in this aquifer is 619 parts per

million (milligrams per liter), and the water is very hard.

Ground water levels are declining in this aquifer because of

heavy pumping. Deep sand and gravel deposits beneath river

valley floors yield some ground water. The quality of this water

is comparable to that in the Trinity Group aquifer, but about 40

percent of all the samples from the alluvium had more than 10

parts per million (milligrams per liter) nitrate. Ground water is

scarce in sloping areas where the underlying sandstone and

shale are near the surface.
of the United States 219

Soils

The dominant soil orders in this MLRA are Entisols,

Inceptisols, Mollisols, and Vertisols. The soils in the area

dominantly have a thermic soil temperature regime, an ustic

soil moisture regime, and smectitic, mixed, or carbonatic

mineralogy. They are very shallow to very deep, well drained,

and generally loamy or clayey. Some Argiustolls (Rowden and

Swenson series) formed in clayey and loamy sediments over

limestone bedrock. Other Argiustolls (Sagerton series) formed

in clayey and loamy alluvium on alluvial plains. Calciustolls

formed in residuum on ridges and plains (Lueders, Springcreek,

and Talpa series), in old alluvium on hills and knobs (Pitzer

series), and in loamy alluvium on stream terraces, alluvial fans,

and plains (Nuvalde and Rowena series). Haplustolls

(Clearfork, Gageby, and Nukrum series) formed in loamy and

clayey alluvium on flood plains. Haplustepts (Owens and

Throck series) and Ustorthents (Harpersville series) formed in

residuum on escarpments and plains. Haplusterts (Leeray series)

formed in clayey alluvium in valleys.

Biological Resources

This area is in the central part of the mixed grass prairie.

Loamy and clayey soils on uplands favor mid and tall grasses.

Big bluestem, little bluestem, Indiangrass, sideoats grama,

Texas cupgrass, vine mesquite, buffalograss, and Texas

wintergrass are the dominant species. Abundant forbs include

catclaw sensitivebrier, heath aster, Engelmann’s daisy, gaura,

prairie clover, dalea, plains blackfoot, and verbena. Scattered

motts of live oak, elm, bumelia, and hackberry are common.

Mesquite has invaded throughout the MLRA, except for areas

of shallow soils. Pricklypear cacti are invasive on some shallow

soils. Soils on low stream terraces and flood plains favor the

growth of bluestems, Indiangrass, switchgrass, grama grasses,

Texas wintergrass, and western wheatgrass. Hackberry, pecan,

elm, and cottonwood are common on the bottom land in the

area.

The major wildlife species in this area are white-tailed deer,

turkey, bobwhite quail, mourning dove, fox squirrel, ducks,

geese, fox, ringtail cat, coyote, bobcat, rabbits, badgers,

songbirds, and rattlesnakes. Rivers, constructed ponds, and

reservoirs provide good opportunities for fishing.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 16%

Grassland—private, 80%

Urban development—private, 2%

Water—private, 1%

Other—private, 1%

Farms and ranches make up nearly all of this area. Most of

the farmland is used for the production of cattle and, to a lesser

extent, sheep and horses. The cropland in the area is limited to

soils that formed on terraces and flood plains. It is commonly

used for small grains or hay for livestock and wildlife. Forage

sorghum and alfalfa are grown for livestock. Wheat, cotton, and

sorghum are the principal crops grown in the area. Some

cropland has been converted to pasture. The leasing of lands for

hunting and other kinds of recreation is common in this area.

The major soil resource concerns are water erosion,

maintenance of the content of organic matter in the soils, and

conservation of soil moisture. The major management concerns

on rangeland are proper stocking rates, a dependable water

supply, brush management, and food and cover for wildlife.

Conservation practices on cropland generally include a

combination of terraces and grassed waterways. They also

include contour farming and crop residue management.

Conservation practices on rangeland generally include proper

grazing use, brush management, fencing, watering facilities,

and measures that improve wildlife habitat. 

78B—Central Rolling Red Plains,

Western Part

This area (shown in fig. 78B-1) is in west-central Texas (92

percent) and southwestern Oklahoma (8 percent). It makes up

about 18,610 square miles (48,220 square kilometers). The

towns of Childress, Post, Snyder, and Big Spring, Texas, are in

this area. Interstate 20 crosses the southern end of this area. Palo

Duro Canyon, Caprock Canyon, and Copper Breaks State Parks

are in this area.

Physiography

Most of this area is in the Osage Plains Section of the

Central Lowland Province of the Interior Plains. The southern

end is in the Central Texas Section of the Great Plains Province

of the Interior Plains, and the western one-third is in the High

Plains Section of the same province and division. This area is

characterized by rolling plains with ancient stream terraces or

terrace remnants associated with stream dissection. Gypsum

interbedded with limestones and dolomites can form a karst

landscape with steep escarpments. Low, stabilized dunes

associated with wind-reworked sandy alluvium are in scattered

areas throughout the MLRA. The erosional surface has stream

channels entrenched in gently dipping bedrock. Elevation is

1,450 feet (440 meters) in the eastern part of the area and

gradually increases to about 2,940 feet (895 meters) in the
220 Major Land Resource Areas

Figure 78B-1: Location of MLRA 78B in Land Resource Region H.

western part. Maximum local relief is about 180 feet (55

meters), but relief is considerably lower in most of the area.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows: RedWashita (1113), 28 percent; Red Headwaters (1112), 24

percent; Brazos Headwaters (1205), 21 percent; Upper

Colorado (1208), 18 percent; Middle Brazos (1206), 6 percent;

and Lower Colorado-San Bernard Coastal (1209), 3 percent.

The major rivers crossing this area from north to south include

the Prairie Dog Town Fork of the Red River, the Pease and

Wichita Rivers, the Salt Fork of the Brazos River, the Double

Mountain Fork of the Brazos River, and the Colorado River.

Geology

This area is underlain by gently dipping Triassic and

Permian deposits that are overlain by slope alluvium and

stream terrace deposits of Quaternary age. Triassic sediments

include calcareous sandstone, shale, clay, and conglomerate in

the Dockum Group. Most of the area is characterized by red

soils weathered from Permian red-bed sediments. Permian

deposits include interbedded shale, sandstone, gypsum, and

dolomite in the Whitehorse and Blaine Formations. Loamy,

sandy, and clayey sediments of Quaternary age overlie Triassic

and Permian deposits on fan remnants and stream terraces. A

surface veneer of siliceous gravel can indicate thin, ancient

terrace deposits. Mining operations for gypsum and gravel are

in scattered areas throughout the MLRA. Oil and gas

production is important in some areas.

Climate

The average annual precipitation in this area is 19 to 26

inches (485 to 660 millimeters), increasing from west to east

across the area. Most of the rainfall occurs as convective

thunderstorms during late spring and early fall. The

precipitation occurring as snow during the winter averages

about 3 inches (8 centimeters). The average annual

temperature is 57 to 65 degrees F (14 to 18 degrees C). The

freeze-free period averages 235 days and ranges from 215 to

260 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 1.8%; ground water, 1.7%

Livestock—surface water, 1.7%; ground water, 0.7%

Irrigation—surface water, 70.2%; ground water, 23.0%

Other—surface water, 0.4%; ground water, 0.4%

The total withdrawals average 510 million gallons per day

(1,930 million liters per day). About 26 percent is from ground

water sources, and 74 percent is from surface water sources. The

moderate, somewhat erratic precipitation provides water for

range and crops. Small ponds on individual farms provide water

for livestock. Some larger ponds on individual farms are used

for flood control, recreation, irrigation water, or water for

livestock. A few large ponds and reservoirs are sources of

municipal water and irrigation water. In the southern part of the

area, the Colorado River and tributaries of the Brazos River are

potential sources of water for irrigation. This river water is

saline because of contamination from human activities and

from natural sources of salts. The salinity levels in reservoirs are

diluted by fresher water inflows from other areas.

Most of the ground water in this area comes from the alluvial

and bolson deposits in Texas. The median level of total

dissolved solids is 771 parts per million (milligrams per liter),

and the ground water is very hard. About 40 percent of all the

samples from the alluvial and bolson deposits had more than 10
of the United States 221

parts per million (milligrams per liter) nitrate. Ground water is

scarce in sloping areas where the underlying sandstone and

shale are near the surface.

The Dog Creek-Blaine aquifer in the extreme southwest

corner of Oklahoma occurs in this MLRA. Water from this

aquifer is somewhat saline and is used for irrigation. It is

unsuitable for public supply. The median level of total

dissolved solids is 3,070 parts per million (milligrams per liter),

and the water is very hard. The water has the highest median

levels of total dissolved solids, hardness, and sulfate of all the

water from aquifers in Oklahoma.

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, Inceptisols, and Mollisols. The soils in the area

dominantly have a thermic soil temperature regime, an ustic

soil moisture regime, and mixed or carbonatic mineralogy.

They are very shallow to very deep, are well drained, and

generally are sandy, loamy, or clayey. Argiustolls (Frankirk,

Sagerton, and Westill series) formed in clayey and loamy

alluvium on stream terraces and alluvial plains. Calciustolls

(Talpa series) and Haplustepts (Obaro, Spade, and Tilvern

series) formed in residuum on hills and ridges. Calciustepts

(Aspermont and Veal series) formed in loamy, calcareous

colluvium and slope alluvium on hillslopes and side slopes.

Haplustalfs (Paducah series) formed in loamy residuum on

plains. Paleustalfs (Delwin, Heatly, Miles, and Nobscot series)

formed in sandy and loamy alluvium, commonly reworked by

the wind, on stream terraces and plains. Ustorthents

(Cottonwood and Knoco series) and Torriorthents (Latom

series) formed in residuum on hills and ridges. Ustipsamments

(Eda, Jester, and Tivoli series) formed in sandy eolian deposits

on dunes adjacent to the major rivers. Ustifluvents (Colorado,

Lincoln, Mangum, and Yomont series) formed in sandy, loamy,

or clayey alluvium on flood plains.

Biological Resources

This area is in the central part of the mixed grass prairie.

Loamy and clayey soils favor the growth of buffalograss,

curlymesquite, sideoats grama, blue grama, vine mesquite, little

bluestem, sand bluestem, Arizona cottontop, silver bluestem,

Texas wintergrass, and tobosagrass. Mesquite, lotebush, and

redberry juniper are common brushy invaders. Sandy soils favor

bluestems, switchgrass, sand lovegrass, sand dropseed, and sand

sagebrush. Some sandy areas support thick stands of shinnery

oak. Saltcedar has invaded areas on flood plains where the

water table is near the surface.

The common wildlife species in this area include whitetailed deer, desert mule deer, coyote, bobcat, black-tailed

jackrabbit, cottontail rabbit, prairie dog, feral hogs, turkey,

bobwhite quail, blue quail, mourning dove, ducks, and geese.

Antelope and mountain lion inhabit a few areas.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 27%

Grassland—private, 70%

Urban development—private, 1%

Water—private, 1%

Other—private, 1%

Ranches and farms make up nearly all of this area. Soils that

formed on Permian red beds, which make up almost threefourths of the area, are used as rangeland. Soils that formed in

Quaternary deposits on terraces or flood plains, which make up

just under one-fourth of the area, are used as cropland. These

nearly level and very gently sloping soils are commonly used

for small grains for livestock and wildlife grazing during fall

and winter. Cotton, wheat, and sorghums are the main crops.

Cotton, alfalfa, and peanuts are irrigated in areas that have an

adequate amount of good-quality water. Many of the farms and

ranches are leased for hunting or other forms of recreation.

The major soil resource concerns include wind erosion,

water erosion, maintenance of the content of organic matter in

the soils, and management of soil moisture. The major

management concerns on rangeland include proper stocking

rates, the need for brush control, and the availability of stock

water in periods of inadequate rainfall.

Conservation practices on cropland generally include a

combination of terraces and grassed waterways. They also

include contour farming and crop residue management.

Conservation practices on rangeland generally include proper

grazing use, brush control (which improves wildlife habitat and

forage production), fencing, watering facilities, and measures

that improve wildlife habitat. 

78C—Central Rolling Red Plains,

Eastern Part

This area (shown in fig. 78C-1) is in central Oklahoma (54

percent), north-central Texas (36 percent), and south-central

Kansas (10 percent). It makes up about 19,565 square miles

(50,705 square kilometers). The cities of Altus, Clinton, Elk

City, and Woodward, Oklahoma, and Abilene, Texas, are in this

area. The Black Kettle National Grasslands, the Washita

National Wildlife Management Area, Altus Force Base (in

Oklahoma), and Dyess Air Force Base (in Texas) also are in this

MLRA.

Physiography

Most of this area is in the Osage Plains Section of the

Central Lowland Province of the Interior Plains. The southwest

tip is in the Central Texas Section of the Great Plains Province
222 Major Land Resource Areas

Figure 78C-1: Location of MLRA 78C in Land Resource Region H.

of the Interior Plains, and the northern tip is in the Plains

Border Section of the same province and division. This area is

characterized by smooth to rolling hills and valleys. It is on

moderately dissected, rolling plains with prominent ridges and

valleys, some local areas of badlands, and numerous stream

terraces. Elevation ranges from about 1,000 feet (305 meters)

along the Red River to 2,000 feet (610 meters) in Oklahoma.

Maximum local relief is about 300 feet (90 meters), and the

average local relief is about 100 feet (30 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows: RedWashita (1113), 30 percent; Middle Brazos (1206), 17 percent;

Red Headwaters (1112), 14 percent; Lower Cimarron (1105), 11

percent; Lower Canadian (1109), 7 percent; Arkansas-Keystone

(1106), 7 percent; North Canadian (1110), 6 percent; Upper

Cimarron (1104), 5 percent; Lower Colorado-San Bernard

Coastal (1209), 2 percent; and Brazos Headwaters (1205), 1

percent. From north to south, some of the major rivers in this

area include the Mule River and Salt Fork of the Arkansas River

in Kansas; the Cimarron, North Canadian, Canadian, and

Washita Rivers and North Fork of the Red River in Oklahoma;

and the Pease, Wichita, and Brazos Rivers in Texas. The Red

River forms the boundary between Texas and Oklahoma in this

MLRA.

Geology

This area is underlain primarily by soft, calcareous

sandstones, siltstones, and shales in red beds of the Wellington

Formation, El Reno Group, Whitehorse Group, Cloud Chief

Formation, and Quartermaster Formation of Permian age in

Oklahoma and of the Wichita and Clear Fork Groups of Permian

age in Texas. Characteristic red soils have formed in most of the

area because of the underlying Permian red-bed sedimentary

rocks.

Climate

The average annual precipitation in this area is 22 to 30

inches (560 to 760 millimeters). Most of the rainfall occurs as

convective thunderstorms during the growing season. The

precipitation occurring as snow during the winter averages

about 6 inches (15 centimeters). The average annual

temperature is 56 to 65 degrees F (13 to 18 degrees C). The

freeze-free period averages 230 days and ranges from 200 to

260 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 7.2%; ground water, 15.4%

Livestock—surface water, 4.4%; ground water, 5.1%

Irrigation—surface water, 12.8%; ground water, 40.7%

Other—surface water, 4.8%; ground water, 9.6%

The total withdrawals average 250 million gallons per day

(950 million liters per day). About 71 percent is from ground

water sources, and 29 percent is from surface water sources. The

moderate, somewhat erratic precipitation provides water for

range and crops. Small ponds on individual farms provide water

for livestock. Some larger ponds on individual farms are used

for flood control, recreation, irrigation water, or livestock water.

A few large ponds and reservoirs are sources of municipal water

and irrigation water. Many of the major rivers that cross this

area are potential sources of irrigation water. Much of this river

water, however, is high in content of salts because of

contamination from human activities and from natural sources

of salts (brine seeps).

Most of the ground water in this area comes from alluvial

and terrace aquifers and is used for irrigation and domestic

supply. The median level of total dissolved solids in the water

in these aquifers ranges from 485 to 585 parts per million

(milligrams per liter) from Oklahoma to Kansas and increases to
of the United States 223

771 parts per million (milligrams per liter) in Texas. The high

amounts of total dissolved solids are the result of gypsum in the

alluvium. This ground water is very hard. About 40 percent of

all the samples from the alluvial and bolson deposits in Texas

had more than 10 parts per million (milligrams per liter) nitrate.

Ground water is scarce in sloping areas where the underlying

sandstone and shale are near the surface.

Soils

The dominant soil orders in this MLRA are Alfisols,

Inceptisols, and Mollisols. The soils in the area dominantly

have a thermic soil temperature regime, an ustic soil moisture

regime, and mixed or smectitic mineralogy. They generally are

moderately deep to very deep, are well drained and moderately

well drained, and generally are loamy or clayey. Paleustolls

(Tillman and Deandale series) and Haplustepts (Quinlan,

Vernon, and Woodward series) formed in residuum on hills and

ridges. Argiustolls (Abbie, Abilene, Carey, St. Paul, and Selman

series) formed in loamy alluvium on stream terraces.

Haplustepts (Burford, Deepwood, Hardeman, and Shrewder

series) formed in mixed alluvium and colluvium on hills and

stream terraces and in valleys. Ustifluvents (Beckman,

Clairemont, Lincoln, and Westola series) formed in alluvium on

flood plains. Ustipsamments (Tivoli and Jester series) formed in

sandy eolian deposits on dunes adjacent to the major rivers.

Biological Resources

This area is in the central part of the mixed grass prairie.

Most of the rangeland in the area supports buffalograss, vine

mesquite, blue grama, tobosagrass, Arizona cottontop, silver

bluestem, little bluestem, and sideoats grama. Also, it has

several hackberry trees and scattered infestations of mesquite.

Sandy and loamy soils on alluvial plains and stream terraces

support little bluestem, silver bluestem, switchgrass, sideoats

grama, blue grama, dropseeds, buffalograss, and vine mesquite.

Bottom land supports blue grama, little bluestem, silver

bluestem, switchgrass, Indiangrass, sedges, sideoats grama,

Texas wintergrass, and vine mesquite. The woody vegetation

on bottom land includes cottonwood and elm along with some

encroaching saltcedar.

The major wildlife species in this area include white-tailed

deer, mule deer, coyote, black-tailed jackrabbit, prairie dog,

bobwhite quail, blue quail, ducks, and geese.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 38%

Grassland—private, 56%; Federal, 1%

Urban development—private, 3%

Water—private, 1%

Other—private, 1%

Farms and ranches make up nearly all of this area. They

produce a combination of grain crops and livestock. Most of

the area is used as rangeland. The more gently sloping areas are

used for pasture or for dry-farmed crops. Small grains, cotton,

and grain sorghum are the principal crops. A few small areas are

irrigated. These areas have a reliable water supply.

Water erosion and conservation of soil moisture are the

major management concerns on cultivated soils and on

overgrazed rangeland. Conservation practices on cropland

generally include contour farming and crop residue

management. Conservation practices on rangeland generally

include proper grazing use, fencing, and development of

watering facilities. 

79—Great Bend Sand Plains

This area is entirely in Kansas (fig. 79-1). It makes up about

7,405 square miles (19,185 square kilometers). Great Bend,

Hutchinson, and Wichita are in this MLRA. U.S. Highways 50,

54, and 56 cross the area. The western part of McConnell Air

Force Base and the Quivira National Wildlife Refuge are in this

area.

Physiography

Most of this area is in the Plains Border Section of the Great

Plains Province of the Interior Plains. The eastern third is in the

Osage Plains Section of the Central Lowland Province of the

Interior Plains. The undulating to rolling plains in this area

generally have narrow valleys, but broad flood plains and

terraces are along the Arkansas River and its larger tributaries.

Elevation ranges from 1,650 to 2,600 feet (505 to 795 meters),

increasing from east to west.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Middle Arkansas (1103), 82 percent, and Arkansas-Keystone

(1106), 18 percent. The Arkansas River bisects the northern

part of this MLRA, and the Ninnescah River crosses the

southern part. In this MLRA, Rattlesnake Creek flows north

and the Little Arkansas River flows south into the Arkansas

River.

Geology

This area is covered by a thick mantle of windblown clays,

silts, and sand and sandy outwash material of Holocene and late

Pleistocene age. Alluvium consisting of silty and clayey

material and coarse gravel is deposited along the Little

Arkansas and Arkansas Rivers. Young, low-elevation dunes

consisting of fine to medium quartz sand are adjacent to the

alluvial areas.
224 Major Land Resource Areas

Figure 79-1: Location of MLRA 79 in Land Resource Region H.

Climate

The average annual precipitation in this area is 24 to 35

inches (610 to 890 millimeters). Most of the rainfall occurs as

high-intensity, convective thunderstorms during the growing

season. The maximum precipitation occurs from the middle of

spring to early in autumn. The annual snowfall ranges from

about 14 inches (35 centimeters) in the southern part of the

area to 20 inches (50 centimeters) in the northern part. The

average annual temperature is 55 to 59 degrees F (13 to 15

degrees C). The freeze-free period averages 210 days and ranges

from 195 to 225 days, increasing in length from northwest to

southeast.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 6.8%; ground water, 4.0%

Livestock—surface water, 0.4%; ground water, 1.2%

Irrigation—surface water, 0.7%; ground water, 80.6%

Other—surface water, 2.0%; ground water, 4.3%

The total withdrawals average 740 million gallons per day

(2,800 million liters per day). About 90 percent is from ground

water sources, and 10 percent is from surface water sources. The

source of water for crops and pasture is the moderate, somewhat

erratic precipitation. In the northern part of the area, the

Arkansas River is a potential source of irrigation water, but it

currently is little used for this purpose. The Ninnescah River is

another potential source of surface water in the area.

Deep sand in the High Plains or Ogallala aquifer yields an

abundance of good-quality ground water. This aquifer provides

water primarily for irrigation but also for domestic supply and

livestock in rural areas and for industry and public supply in

Wichita and in other towns or cities in the MLRA. The ground

water in this aquifer has the lowest levels of total dissolved

solids of any aquifer in Kansas, 340 parts per million

(milligrams per liter).

Soils

The dominant soil orders in this MLRA are Mollisols,

Alfisols, and Entisols. Most of the soils in the area have a mesic

soil temperature regime, an ustic soil moisture regime, and

mixed mineralogy. They are moderately deep to very deep,

poorly drained to excessively drained, and loamy or sandy.

Nearly level and gently undulating Argiustolls formed in loamy

alluvium on paleoterraces in river valleys (Naron and Farnum

series). Haplustalfs formed in loamy alluvium on terraces

(Nickerson series) or in sandy eolian deposits on dunes on

paleoterraces (Pratt series). Natrustalfs formed in loamy,

calcareous alluvium on terraces (Darlow series). Endoaquolls

formed in loamy alluvium on flood plains (Ninnescah series).

Ustipsamments (Tivin series) are on the steeper hummocks and

dunes. Nearly level Argiaquolls (Carbika series) in depressions

and in areas with no defined drainage pattern are moderately

extensive throughout the area. Haplustolls on flood plains

(Imano series) and terraces (Willowbrook series) are along the

major streams.

Biological Resources

This area supports tall prairie grasses. Sand bluestem, big

bluestem, little bluestem, switchgrass, and Indiangrass are the

dominant species. Sand bluestem, little bluestem, sand

lovegrass, and giant sandreed grow on sandy soils.

The major wildlife species in this area include white-tailed

deer, mule deer, coyote, black-tailed jackrabbit, prairie dog,

bobwhite quail, blue quail, ducks, and geese.
of the United States 225

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 67%

Grassland—private, 23%; Federal, 1%

Forest—private, 1%

Urban development—private, 5%

Water—private, 1%

Other—private, 2%

Nearly all of this area is in farms or ranches. Most of the area

is cropland. Cash-grain farming is the principal enterprise. Hard

winter wheat is the major crop, but grain sorghum and alfalfa

also are grown. The grassland in the area consists of sandy soils

and steeply sloping areas. It supports native grasses grazed by

beef cattle.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter in the

soils, and soil moisture management. The major management

concerns on grassland are plant health and vigor and control of

noxious and invasive weeds.

Conservation practices on cropland generally include highresidue crops in the cropping system; systems of crop residue

management, such as no-till and strip-till systems; conservation

crop rotations; wind stripcropping; and nutrient and pest

management. Conservation practices on rangeland generally

include brush management, prescribed burning, control of

noxious weeds, pest management, watering facilities, and

proper grazing use. 

Figure 80A-1: Location of MLRA 80A in Land Resource Region H.

80A—Central Rolling Red Prairies

This area (shown in fig. 80A-1) is in Oklahoma (82 percent),

Texas (11 percent), and Kansas (7 percent). It makes up about

19,925 square miles (51,635 square kilometers). It includes the

towns or cities of Enid, Stillwater, Oklahoma City, Chickasha,

and Ft. Sill, Oklahoma; Wichita Falls, Texas; and Wellington,

Kansas. Interstates 35, 40, and 44 cross this area. The Sheppard

Air Force Base in Texas and the Salt Plains National Wildlife

Refuge in Oklahoma are in this area.

Physiography

This area is in the Osage Plains Section of the Central

Lowland Province of the Interior Plains. It is characterized by

dark red Permian rocks that are exposed dominantly on gently

sloping plains. The plains are dissected by rivers flowing from

northwest to southeast. Elevation ranges from about 850 to

1,500 feet (260 to 455 meters). Local relief commonly is less

than 100 feet (30 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows: RedWashita (1113), 34 percent; Arkansas-Keystone (1106), 27

percent; Lower Cimarron (1105), 23 percent; Lower Canadian

(1109), 8 percent; and North Canadian (1110), 8 percent. From

north to south, the major rivers draining this area include the

Chickaskia and Bluff Rivers in Kansas; the Salt Fork of the

Arkansas River and the Cimarron, North and South Canadian,

Washita, Cache, and Red Rivers in Oklahoma; and branches of

the Wichita River in Texas.

Geology

The plains in this area consist mainly of Pleistocene-age,

loamy and clayey sediments that overlie Permian sandstones

and shales. The Pleistocene sediments are primarily stream

terrace deposits that follow the gradient of the major streams

from northwest to southeast. The shales and sandstones are part
226 Major Land Resource Areas

of the El Reno Group. They dip gently southwestward toward

the Anadarko Basin.

Climate

The annual average precipitation in this area is 25 to 38

inches (635 to 965 millimeters). The annual amount of

precipitation may fluctuate widely from year to year. Most of

the rainfall occurs as high-intensity, convective thunderstorms

during spring and fall. The average annual temperature is 57 to

64 degrees F (14 to 18 degrees C). The freeze-free period

averages 235 days and ranges from 205 to 265 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 25.7%; ground water, 11.9%

Livestock—surface water, 3.8%; ground water, 2.7%

Irrigation—surface water, 8.4%; ground water, 23.4%

Other—surface water, 15.3%; ground water, 8.8%

The total withdrawals average 330 million gallons per day

(1,250 million liters per day). About 47 percent is from ground

water sources, and 53 percent is from surface water sources. The

moderate, somewhat erratic precipitation is the source of water

for crops and pasture. Several large rivers that cross the area

from west to east are potential sources of irrigation water. A

fairly high content of salts in these rivers limits use of the river

water. The North Canadian and Washita Rivers have goodquality water and are used for municipal supplies. Small ponds

on individual farms provide flood control, opportunities for

recreation, irrigation water, and livestock water. A few large

ponds and reservoirs are sources of municipal water and are

used for recreation.

Most of the ground water in this area comes from alluvial

and terrace aquifers and is used for irrigation, livestock, and

domestic supply. The median level of total dissolved solids in

the water in these aquifers ranges from 485 to 585 parts per

million (milligrams per liter) from Oklahoma to Kansas. The

Garber-Wellington aquifer is along the southeastern edge of

this MLRA in Oklahoma. This aquifer provides drinking water

to many communities in the area near Oklahoma City. The

water in this aquifer is as hard as the water in the alluvial and

terrace deposits, but the median level of total dissolved solids

is only 372 parts per million (milligrams per liter). Ground

water is scarce and generally is highly mineralized in sloping

areas where the underlying sandstone and shale are near the

surface. There are no significant aquifers in the part of this

MLRA in Texas.

Soils

The dominant soil order in this MLRA is Mollisols. The

soils in the area dominantly have a thermic soil temperature

regime, an ustic soil moisture regime, and mixed, siliceous, or

smectitic mineralogy. They generally are shallow to very deep,

are well drained, and generally are loamy or clayey. Paleustolls

(Bethany, Tabler, Renfrow, Kirkland, Norge, Foard, and

Deandale series) and Argiustolls (Teller and Pond Creek series)

formed in clayey and loamy alluvium of Pleistocene age. They

are on plains. Argiustolls (Zaneis, Coyle, Mulhall, Grant, and

Kingfisher series) and Haplustolls (Lucien series) formed in

Permian sandstone residuum on ridges and hillslopes.

Haplustalfs (Grainola and Steedman series) formed in Permian

shale residuum on hillslopes. Haplustolls (Port, Ashport, Dale,

Miller, and Reinach series) formed in Holocene alluvium on

flood plains.

Biological Resources

This area supports tall and mid prairie grasses. Tracts of

native vegetation still occur on farms and ranches throughout

the area. Big bluestem, Indiangrass, switchgrass, and little

bluestem are the dominant species. The plant diversity,

including grasses, forbs, legumes, and woody species, is very

high.

The major wildlife species in this area include white-tailed

deer, coyote, cottontail rabbit, bobwhite quail, doves,

meadowlark, scissortail flycatcher, ducks, and geese. Numerous

manmade reservoirs and ponds provide good opportunities for

fishing.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 43%

Grassland—private, 43%; Federal, 1%

Forest—private, 4%

Urban development—private, 6%

Water—private, 2%

Other—private, 1%

Farms and ranches make up nearly all of the private land in

this area. Cropland and grassland (rangeland and pasture) make

up nearly all of the land area. Most farms include both cropland

and grassland and produce a combination of grain crops and

beef cattle. Wheat is the principal crop, but soybeans, corn,

grain sorghum, and cotton also are grown in the area. The

grassland in the area is used for cow-calf and stocker cattle

operations.
of the United States 227

Figure 80B-1: Location of MLRA 80B in Land Resource Region H.

The main resource concerns on cropland include water

erosion, surface compaction, conservation of soil moisture, and

maintenance of the content of organic matter in the soils. The

main resource concerns on grassland include plant health and

vigor and control of noxious and invasive species.

Conservation practices on cropland generally include highresidue crops in the cropping system; systems of crop residue

management, such as no-till and strip-till; conservation crop

rotations; and nutrient and pest management. Conservation

practices on grassland generally include brush management,

prescribed burning, control of noxious weeds, pest

management, development of watering facilities, and proper

grazing use. 

80B—Texas North-Central Prairies

This area is in two separate parts in north-central Texas (fig.

80B-1). It makes up about 6,195 square miles (16,055 square

kilometers). The towns of Breckenridge, Brownwood, Eastland,

Graham, Jacksboro, and Mineral Wells are in this area.

Physiography

The northern part of this area is in the Osage Plains Section

of the Central Lowland Province of the Interior Plains. The

southern part is in the Central Texas Section of the Great Plains

Province of the Interior Plains. The area is primarily an eroded

plateau. The drainage divides are dissected and are gently

rolling to steep, and the valleys are narrow and have steep

sides. Stream terraces and flood plains are associated with

present-day streams, and erosional remnants of older terraces

are indicative of relict stream courses. Well developed flood

plains are along the Brazos and Clear Fork Rivers. Elevation

ranges from 660 to 2,310 feet (200 to 705 meters). Geologic

weathering has produced a subdued, terraced topography.

Prominent scarps with relief of 15 feet (5 meters) to more than

100 feet (30 meters) are common throughout the area.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Middle Brazos (1206), 49 percent; Lower Colorado-San

Bernard Coastal (1209), 29 percent; Trinity (1203), 18 percent;

Red-Washita (1113), 2 percent; and Lower Brazos (1207), 2

percent. The Brazos River and the Clear Fork of the Brazos

River drain the northern part of this area, and the Colorado

River drains the southern part.

Geology

This area is underlain primarily by limestones and shales of

Pennsylvanian age and by Cretaceous sandstone. The Canyon

Group of Pennsylvanian age crops out throughout most of the

area. It consists of the Wolf Mountain Shale, Winchell

Limestone, Placid Shale, Ranger Limestone, Colony Creek

Shale, and Home Creek Limestone. The overlying Thrifty and

Graham Formations (Cisco Group) consist of interbedded light

gray and brown limestones, sandstones, and shales of

Pennsylvanian age. Erosional remnants of the Antlers

Sandstone of Cretaceous age crop out in the southern part of

this area. In places stones and boulders cover the surface.

Sandy and loamy stream terrace deposits occur in the river

valleys. Erosional remnants of older stream terraces are on

uplands.

Climate

The average annual precipitation in this area is 26 to 33

inches (660 to 840 millimeters). Most of the rainfall occurs as

high-intensity, convective thunderstorms during spring and fall.

The average annual temperature is 63 to 66 degrees F (17 to 19

degrees C). The freeze-free period averages 260 days and ranges

from 245 to 270 days.
228

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 34.7%; ground water, 0.0%

Livestock—surface water, 23.8%; ground water, 0.7%

Irrigation—surface water, 34.0%; ground water, 0.0%

Other—surface water, 6.8%; ground water, 0.0%

The total withdrawals average 15 million gallons per day

(55 million liters per day). About 1 percent is from ground water

sources, and 99 percent is from surface water sources. The

moderate, somewhat erratic rainfall is the source of water for

crops and range. Summer droughts are common. The larger

rivers, such as the Brazos and Colorado Rivers, flow most of the

year, but local streams flow intermittently. Several large lakes

and flood-detention reservoirs are in the area. Some rural

residents depend on rural water systems supplied from lakes for

water; others depend on private lakes. Most livestock water

comes from streams or ponds. Ground water is scarce in this

MLRA.

Soils

The dominant soil orders in this MLRA are Alfisols,

Inceptisols, Mollisols, and Vertisols. The soils in the area

dominantly have a thermic soil temperature regime, an ustic

soil moisture regime, and mixed, carbonatic, or smectitic

mineralogy. Most of the soils formed in material weathered

from Cretaceous sedimentary rocks. The soils are very shallow

to very deep, are well drained or moderately well drained, and

generally are loamy or clayey.

Haplustolls (Palopinto and Eckrant series) formed in

limestone residuum on hills, ridges, and plains. Argiustolls

(Rumple and Speck series) formed in colluvium over limestone

residuum on low-relief plateaus and cuestas. Haplusterts

(Leeray series) and Haplustolls (Nukrum series) formed in

clayey alluvium on footslopes at the base of cuesta scarps.

Haplustepts (Owens and Throck series) formed in claystone

residuum on escarpments, plains, and footslopes. Haplustalfs

(Exray and Callahan series) and Paleustalfs (Bonti and Truce

series) formed in residuum on hills and ridges. Calciustolls

formed in residuum on plains (Rowena and Set series) and in

alluvium on alluvial fans and stream terraces (Nuvalde series).

Argiustolls (Sagerton series), Paleustalfs (Winters and Wichita

series), and Haplustalfs (Thurber series) formed in loamy and

clayey alluvium on stream terraces. Haplustolls (Clearfork,

Deleon, Gageby, and Gowen series) formed in loamy and clayey

alluvium on flood plains. Ustifluvents (Bunyan, Lincoln,

Westola, and Yahola series) formed in sandy and loamy

alluvium on flood plains.

Biological Resources

This area supports oak savanna vegetation with an

understory of tall grasses. Little bluestem, big bluestem,

Indiangrass, and switchgrass can grow on the deeper soils.

Texas wintergrass, little bluestem, silver bluestem, buffalograss,

and sideoats grama are dominant on shallow soils. Post oak,

blackjack oak, sumac, bumelias, mesquite, and elm are the

dominant woody species. The area supports numerous

perennial forbs, including Maximilian sunflower, heath aster,

bush sunflower, and Engelmann’s daisy.

The major wildlife species in this area are white-tailed deer,

coyote, cottontail rabbit, bobwhite quail, doves, meadowlark,

scissortail flycatcher, ducks, and geese. Numerous manmade

reservoirs and ponds provide good opportunities for fishing.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 10%

Grassland—private, 84%

Urban development—private, 3%

Water—private, 2%

Other—private, 1%

Farms and ranches make up nearly all of this area.

Rangeland and pasture are the dominant land uses. Most of the

rangeland and pasture is grazed by beef cattle, but a small

acreage is grazed by sheep and goats. Many ranches are

managed not only for livestock but also for wildlife, including

white-tailed deer, dove, and quail. A minor acreage of cropland

in areas of deep soils is used for wheat, oats, cotton, or grain

sorghum.

The main resource concerns are the encroachment of woody

species, conservation of soil moisture, and control of water

erosion. The important conservation practices in this area

generally include reasonable stocking rates and rotational

grazing. 
229

Figure I-1: Location of Land Resource Region I.

I—Southwest Plateaus and Plains Range

and Cotton Region

This region is entirely in Texas (fig. I-1). It makes up 72,340

square miles (187,460 square kilometers).

In the northern and western parts of the region, there are

mesas, plateaus, and limestone ridges and hills, deeply incised

canyons are common, and the valley floors are level to gently

sloping. The rest of the region is either on the Gulf Coast Plain

or in the Rio Grande Valley and is a nearly level to gently

undulating plain with low hills.

This region is in the warmer part of the southern Great

Plains. Moderate precipitation is accompanied by high

temperatures, and the effectiveness of precipitation is low. The

average annual precipitation ranges from 20 to 29 inches (510

to 735 millimeters). Generally, much of the precipitation falls in

spring and autumn. The average annual temperature ranges

from 66 to 70 degrees F (19 to 21 degrees C). The freeze-free

period ranges from 265 to 320 days, increasing in length from

north to south. Freeze-free years are common in the extreme

southern part of the region.

The total withdrawals of freshwater in this region average

about 2,920 million gallons per day (11,050 million liters per

day). About 57 percent is from surface water sources, and 43

percent is from ground water sources. About 47 percent of the

water is used for irrigation, 32 percent is used for cooling

thermoelectric power plants, and 19 percent is used for public

supply.

The soils in this region are dominantly Alfisols, Aridisols,

Inceptisols, Mollisols, and Vertisols. The major soil suborders

on uplands are Calcids in the western part of the region and

Ustalfs, Ustolls, Usterts, and Ustepts in the eastern part. Ustolls

and Usterts are especially prominent in the southeastern part.

The soils in this region dominantly have a hyperthermic soil

temperature regime, an ustic soil moisture regime, and mixed

mineralogy.

About 99 percent of the land in this region is privately

owned. The native vegetation consists mainly of shrubs

interspersed with grasses and scattered trees (fig. I-2). Grazing is
230 Major Land Resource Areas

Figure I-2: Vegetation along the Pecos River in an area of Land Resource Region I.

the dominant land use in most of the region, but wheat, grain

sorghum, and other small grain crops are grown in areas where

the soils, topography, and moisture supply are favorable.

Irrigated cotton is an important crop in the southeastern part of

the region. Citrus fruits and winter vegetables are grown in the

lower Rio Grande Valley. The major resource concern is

overgrazing. The invasion of undesirable species also is a

concern. 
of the United States 231

Figure 81A-1: Location of MLRA 81A in Land Resource Region I.

81A—Edwards Plateau, Western Part

This area is entirely in Texas (fig. 81A-1). It makes up about

16,550 square miles (42,885 square kilometers). The cities of

San Angelo and Fort Stockton and the towns of Big Lake,

McCamey, Ozona, and Sheffield are in this MLRA. Interstate 20

crosses the northern part of the area, and Interstate 10 crosses

the middle of the area. The eastern part of Amistad National

Recreation Area is in this MLRA.

Physiography

This area is primarily in the Edwards Plateau Section of the

Great Plains Province of the Interior Plains. The southwest

corner is in the Mexican Highland Section of the Basin and

Range Province of the Intermontane Plateaus. Mesas, plateaus,

and limestone ridges and hills with deep canyons and nearly

level to gently sloping valley floors characterize the area.

Elevation of the Rio Grande decreases from 1,200 feet (365

meters) at the western end of the area to 1,000 feet (305

meters) at the eastern end, and the upland areas increase in

elevation northward to 2,700 feet (825 meters) on plateaus and

mesas.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Lower Colorado-San Bernard Coastal (1209), 34 percent;

Lower Pecos (1307), 32 percent; Rio Grande-Amistad (1304),

26 percent; Upper Colorado (1208), 4 percent; Rio GrandeFalcon (1308), 2 percent; and Nueces-Southwestern Texas

Coastal (1211), 2 percent. The Concho and Pecos Rivers and

the Big Canyon and Devil’s Rivers, northern tributaries of the

Rio Grande, drain this area. The International Amistad

Reservoir, on the Rio Grande, is in the southern part of the area.

Geology

This area is underlain primarily by limestones in the Austin

Chalk, Boquillas Flags, Devil’s River, Edwards, Buda, and Del

Rio Clay Formations of Cretaceous age. Quaternary alluvium is

in river valleys.

Climate

The average annual precipitation is 15 to 26 inches (380 to

660 millimeters) in most of this area, but it is 13 to 15 inches

(330 to 380 millimeters) in the southwestern third of the area.

Precipitation fluctuates widely from year to year and occurs

mainly in spring and fall. The average annual temperature is 61

to 69 degrees F (16 to 21 degrees C). The freeze-free period

averages 275 days and ranges from 220 to 325 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 1.5%; ground water, 1.4%

Livestock—surface water, 0.9%; ground water, 4.0%

Irrigation—surface water, 16.4%; ground water, 71.7%

Other—surface water, 2.0%; ground water, 2.0%

The total withdrawals average 245 million gallons per day

(925 million liters per day). About 79 percent is from ground

water sources, and 21 percent is from surface water sources.

Water is scarce throughout the area because of limited and

erratic precipitation and few perennial streams. Reservoirs

outside San Angelo provide public supply and municipal water

and some limited irrigation water. The reservoir behind Amistad

Dam, on the Rio Grande, also provides some irrigation water.

The surface water is not of good quality. High suspended

sediment and salt loads limit its use.

Ground water is generally very deep in the Edwards-Trinity

Plateau aquifer. It is very hard water with a median level of total

dissolved solids of 773 parts per million (milligrams per liter).

This aquifer provides water for livestock, domestic use, and

irrigation. About 35 percent of the samples from this aquifer

contained nitrate in excess of the national drinking water

standard of 10 parts per million (milligrams per liter). Rio

Grande valley fill deposits provide some ground water for

irrigation in the area. The ground water is recharged by the

river, so the water quality is similar to that of the Rio Grande.
232 Major Land Resource Areas

Soils

The dominant soil order in this MLRA is Mollisols. Most of

the soils are Calciustolls or Haplustolls. They are well drained

and generally are shallow and have a skeletal particle-size

class. The soils have a thermic or hyperthermic soil temperature

regime, an ustic soil moisture regime, and carbonatic or mixed

mineralogy. Rock outcrop makes up a significant portion of the

area. Shallow Calciustolls (Ector and Langtry series) formed on

mesas, plateaus, and hills underlain by limestone bedrock.

Other shallow Calciustolls (Mailtrail series) have a petrocalcic

horizon and formed on uplands and footslopes. Very deep

Haplustolls (Rio Diablo and Dev series) and very deep

Calciustolls (Angelo series) formed in nearly level to gently

sloping areas in valleys and on flood plains.

Biological Resources

This area supports a plant community of shrubs and short or

mid grasses. The vegetation includes juniper, mesquite,

lotebush, shin oak, sumac, Texas pricklypear, tasajillo,

kidneywood, agarito, yucca, Lindheimer silktassel, sotol,

catclaw, Mexican persimmon, sideoats grama, threeawn, Texas

grama, hairy grama, curly mesquite, buffalograss, and hairy

tridens.

Some of the major wildlife species in this area are whitetailed deer, javelina, coyote, fox, bobcat, raccoon, skunk,

opossum, jackrabbit, cottontail, turkey, bobwhite quail, scaled

quail, white-winged dove, and mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 6%

Grassland—private, 92%

Urban development—private, 2%

Ranches managed for grazing and wildlife habitat make up

nearly all of this area. Livestock grazing is the principal land

use. Some of the cropland in the area is irrigated.

 The major soil resource concern is the erosion caused by

overgrazing. Conservation practices on rangeland generally

include reasonable stocking rates, proper grazing use, timely

deferment of grazing, and pasture rotation. 

81B—Edwards Plateau, Central Part

This area is entirely in south-central Texas (fig. 81B-1). It

makes up about 11,125 square miles (28,825 square

kilometers). The towns of Fredericksburg, Junction, Menard,

Rocksprings, and Sonora are in this MLRA. Interstate 10

crosses the middle part of the area. A few State parks and State

historic sites are in this MLRA.

Physiography

Most of this area is in the Edwards Plateau Section of the

Great Plains Province of the Interior Plains. The northern part is

in the Central Texas Section of the same province and division.

Plateaus and limestone hills, incised by deep canyons, and

nearly level to gently sloping valley floors characterize the

area. Elevation is 900 feet (275 meters) at the southern end of

the area and increases northward to 2,500 feet (760 meters) on

the limestone plateaus.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Lower Colorado-San Bernard Coastal (1209), 67 percent; Rio

Grande-Amistad (1304), 18 percent; Nueces-Southwestern

Texas Coastal (1211), 5 percent; Middle Brazos (1206), 3

percent; Upper Colorado (1208), 3 percent; Central Texas

Coastal (1210), 2 percent; and Lower Pecos (1307), 2 percent.

The Guadalupe, Pedernales, West Nueces, Llano, and San Saba

Rivers drain this area. The Colorado River crosses the northeast

tip of the area.

Geology

This area is underlain primarily by limestones in the Austin

Chalk, Boquillas Flags, Segovia, Fort Terrett, Devil’s River,

Salmon Peak, McKnight, Edwards, Buda, and Del Rio Clay

Figure 81B-1: Location of MLRA 81B in Land Resource Region I.
of the United States 233

Formations of Cretaceous age. Quaternary alluvium is in river

valleys.

Climate

The average annual precipitation in this area is 19 to 32

inches (485 to 815 millimeters). Most of the rainfall occurs in

spring and fall. The average annual temperature is 62 to 68

degrees F (17 to 20 degrees C). The freeze-free period averages

250 days and ranges from 230 to 270 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 5.8%; ground water, 24.8%

Irrigation—surface water, 8.2%; ground water, 61.3%

Other—surface water, 0.0%; ground water, 0.0%

The total withdrawals average 24 million gallons per day (90

million liters per day). About 86 percent is from ground water

sources, and 14 percent is from surface water sources. The

amount of water is limited throughout most of the area but is

abundant along the spring-fed, perennial streams. The surface

water generally is of good quality, although high salt loads

decrease water quality in a downstream direction. Most of the

surface water is used for livestock or irrigation.

Ground water is generally very deep in the Edwards-Trinity

Plateau aquifer. It is very hard water with a median level of total

dissolved solids of 773 parts per million (milligrams per liter).

This aquifer provides water for livestock, domestic use, and

irrigation. About 35 percent of the samples from this aquifer

contained nitrate in excess of the national drinking water

standard of 10 parts per million (milligrams per liter). The

Edwards-Trinity Plateau aquifer does not occur in the

northeastern part of the area. Valley fill deposits along some of

the larger streams in this MLRA supply some ground water for

livestock, domestic use, and irrigation.

Soils

Most of the soils in this MLRA are Calciustolls and

Haplustolls. They are well drained and generally are shallow

and have a skeletal particle-size class. They have a thermic soil

temperature regime, an ustic soil moisture regime, and

carbonatic or mixed mineralogy. Rock outcrop makes up a

significant portion of the area. Shallow Haplustolls and

Calciustolls (Eckrant and Tarrant series) formed on mesas,

plateaus, and hills underlain by limestone bedrock. Very deep

Calciustolls (Nuvalde and Knippa series) formed in nearly level

to gently sloping valleys. Very deep Haplustolls (Oakalla

series) formed on flood plains.

Biological Resources

This area supports a plant community of trees, shrubs, and

short or mid grasses. The vegetation includes live oak, juniper,

Texas oak, shin oak, cedar elm, netleaf hackberry, flameleaf

sumac, agarito, Mexican persimmon, Texas pricklypear,

kidneywood, saw greenbriar, Texas wintergrass, little bluestem,

curly mesquite, Texas grama, Halls panicum, purple threeawn,

hairy tridens, cedar sedge, two-leaved senna, mat euphorbia,

and rabbit tobacco.

Some of the major wildlife species in this area are whitetailed deer, javelina, coyote, fox, bobcat, raccoon, skunk,

opossum, jackrabbit, cottontail, turkey, bobwhite quail, scaled

quail, white-winged dove, and mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 4%

Grassland—private, 95%

Urban development—private, 1%

Nearly all of this area is used for livestock grazing and

wildlife habitat. Some areas are used as dry-farmed or irrigated

cropland. Small grains and forage sorghum are the principal

crops.

 The major soil resource management concern is the erosion

caused by overgrazing and cultivation. Conservation practices

on rangeland generally include reasonable stocking rates,

proper grazing use, timely deferment of grazing, and pasture

rotation. Conservation practices on cropland generally include

terraces, grassed waterways, conservation tillage, and irrigation

water management. 

81C—Edwards Plateau, Eastern Part

This area is entirely in Texas (fig. 81C-1). It makes up about

8,060 square miles (20,890 square kilometers). The towns of

Bandera, Boerne, Medina, Johnson City, Burnet, Luckenbach,

and Liberty Hill and the western half of Austin are in this

MLRA. Interstate 10 crosses the western third of the area. The

Lyndon B. Johnson National Historical Park is in this MLRA.

Physiography

The southern two-thirds of this area is in the Edwards Plateau

Section of the Great Plains Province of the Interior Plains. The

northern third is in the Central Texas Section of the same province

and division. Limestone ridges and canyons and nearly level to

gently sloping valley floors characterize the area. Elevation is
234 Major Land Resource Areas

Figure 81C-1: Location of MLRA 81C in Land Resource Region I.

900 feet (275 meters) at the eastern end of the area and increases

westward to 2,000 feet (610 meters) on ridges.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Central Texas Coastal (1210), 39 percent; Nueces-Southwestern

Texas Coastal (1211), 25 percent; Lower Colorado-San Bernard

Coastal (1209), 22 percent; and Lower Brazos (1207), 14

percent. From northeast to southwest, the Colorado, Pedernales,

Blanco, Guadalupe, Medina, Frio, and Nueces Rivers cross this

area.

Geology

This area is underlain primarily by limestones in the Glen

Rose, Fort Terrett, and Edwards Formations of Cretaceous age.

Quaternary alluvium is in river valleys.

Climate

The average annual precipitation in most of this area is 24 to

30 inches (610 to 760 millimeters). It is as high as 35 inches

(890 millimeters) in the northeastern part of the area. Most of

the rainfall occurs in spring and fall. The average annual

temperature is 63 to 68 degrees F (17 to 20 degrees C). The

freeze-free period averages 275 days and ranges from 235 to

310 days, lengthening to the south.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 17.0%; ground water, 17.1%

Livestock—surface water, 0.5%; ground water, 0.3%

Irrigation—surface water, 0.4%; ground water, 0.4%

Other—surface water, 56.5%; ground water, 7.8%

The total withdrawals average 1,210 million gallons per day

(4,580 million liters per day). About 26 percent is from ground

water sources, and 74 percent is from surface water sources. The

amount of water is limited throughout most of the area but is

abundant along spring-fed, perennial streams. A series of large

reservoirs on the Colorado River in an area west of Austin

provides abundant, good-quality surface water for public supply

and for municipal and industrial uses. The Pedernales River

empties into these reservoirs.

Ground water is generally deep. Three of the seven principal

aquifers in Texas are beneath this MLRA. Sandstone and

carbonate layers in the Trinity Group are the principal aquifers

in the MLRA. The ground water in these layers is very hard and

has a median level of 619 parts per million (milligrams per liter)

total dissolved solids. About 30 percent of the samples from

this aquifer exceeded the national drinking water standard of

10 parts per million (milligrams per liter) for nitrate. The aquifer

provides water for livestock, domestic use, public supply, and

some irrigation.

The Edwards-Trinity Plateau aquifer underlies the

southwestern part of this area. The water in this aquifer is very

hard and has a median level of total dissolved solids of 773

parts per million (milligrams per liter). This aquifer provides

water for livestock, domestic use, and some irrigation. About 35

percent of the samples from this aquifer contained nitrate in

excess of the national drinking water standard.

The Edwards-Balcones Fault Zone aquifer is in the

southeastern part of this area and along the eastern boundary of

the area. The water in this aquifer is near the surface. It is very

hard and has a median level of 371 parts per million (milligrams

per liter) total dissolved solids. This aquifer provides large

amounts of water from springs. The water is used for public

supply.

Valley fill deposits along some of the larger streams in this

MLRA provide some ground water for livestock, domestic use,

and irrigation.

Soils

The dominant soil orders in this MLRA are Inceptisols and

Mollisols. Most of the soils are Calciustolls, Haplustolls, or

Haplustepts. They are well drained and generally are shallow

and have a skeletal particle-size class. They have a thermic soil

temperature regime, an ustic soil moisture regime, and

carbonatic or mixed mineralogy. Rock outcrop makes up a
of the United States 235

significant portion of the area. Shallow and moderately deep

Haplustepts (Brackett and Kerrville series) formed on the side

slopes of ridges. Shallow Haplustolls and Calciustolls (Eckrant

and Tarrant series) formed on the summit on ridges. Very deep

Calciustolls and Haplustolls (Lewisville and Krum series)

formed in nearly level to gently sloping valleys. Very deep

Haplustolls (Frio series) formed on flood plains.

Biological Resources

This area supports a plant community of trees, shrubs, and

mid or tall grasses. The vegetation includes live oak, juniper,

Texas oak, shin oak, cedar elm, evergreen sumac, escarpment

cherry, saw greenbriar, mescal bean, poison oak, twistleaf

yucca, elbowbush, cedar sedge, little bluestem, Neally grama,

Texas grama, meadow dropseed, Texas wintergrass, curly

mesquite, pellitory, noseburn, spreading sida, woodsorrel, and

mat euphorbia.

Some of the major wildlife species in this area are whitetailed deer, javelina, coyote, fox, bobcat, raccoon, skunk,

opossum, jackrabbit, cottontail, turkey, bobwhite quail, scaled

quail, white-winged dove, and mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 3%

Grassland—private, 84%; Federal, 1%

Urban development—private, 10%

Water—private, 1%

Other—private, 1%

Most of this area is used for grazing and wildlife habitat. A

few areas are used as cropland. Small grains and forage sorghum

are the principal crops.

The major soil resource concern is the erosion caused by

overgrazing and cultivation. Conservation practices on

rangeland generally include reasonable stocking rates, proper

grazing use, timely deferment of grazing, and pasture rotation.

The important conservation practices on cropland include

terraces, grassed waterways, conservation tillage, and irrigation

water management. 

Figure 81D-1: Location of MLRA 81D in Land Resource Region I.

81D—Southern Edwards Plateau

This area is entirely in Texas (fig. 81D-1). It makes up about

2,495 square miles (6,465 square kilometers). The towns of

Dryden, Langtry, and Sanderson are in this MLRA. U.S.

Highway 90 connects those towns, and U.S. Highway 385

crosses the western end of the area. The Rio Grande, which is

the national boundary between Texas and Mexico, borders the

area on the south. The western part of the Amistad National

Recreation Area and part of the Big Bend National Park are in

this MLRA.

Physiography

The eastern half of this area is in the Edwards Plateau

Section of the Great Plains Province of the Interior Plains. The

western half is in the Mexican Highland Section of the Basin

and Range Province of the Intermontane Plateaus. Steep

limestone hills and mountains with deep canyons and nearly

level to gently sloping valley floors characterize the area.

Elevation of the Rio Grande decreases from 1,800 feet (550

meters) at the western end of the area to 1,200 feet (365 meters)

at the eastern end, and upland areas increase in elevation

northward to 3,500 feet (1,065 meters) in the mountains.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows: Rio

Grande-Amistad (1304), 96 percent, and Lower Pecos (1307), 4

percent. Short tributaries to the Rio Grande cross this area. From

west to east, they include the Maravillas Canyon, San

Francisco, and Big Canyon Rivers. The Pecos River joins the

Rio Grande in the far eastern part of the area.
236 Major Land Resource Areas

82A—Texas Central Basin

This area is entirely in Texas (fig. 82A-1). It makes up about

2,635 square miles (6,830 square kilometers). The towns of

Mason and Llano are in this MLRA. U.S. Highway 87 crosses

the western half of the area. Enchanted Rock State Natural Area

is in the southern part of the MLRA.

Physiography

This area is in the Central Texas Section of the Great Plains

Province of the Interior Plains. Hills, ridges, and plains

characterize the area. Elevation is 1,200 feet (365 meters) at the

Geology

This area is underlain primarily by limestones in the Austin

Chalk, Boquillas Flags, Devil’s River, Santa Elena, Buda, and

Del Rio Clay Formations of Cretaceous age. Quaternary sand

and gravel are in the river valleys.

Climate

The average annual precipitation is 10 to 15 inches (255 to

380 millimeters) in most of this area. It increases to 18 inches

(455 millimeters) in the far eastern part of the area. The

precipitation fluctuates widely from year to year. Most of the

precipitation is received in late summer. The average annual

temperature is 63 to 70 degrees F (17 to 21 degrees C). The

freeze-free period averages 270 days and ranges from 245 to

295 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 60.1%; ground water, 39.9%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 0.0%; ground water, 0.0%

The total withdrawals average 3 million gallons per day (11

million liters per day). About 40 percent is from ground water

sources, and 60 percent is from surface water sources. Water is

scarce throughout the area because of limited and erratic

precipitation and few perennial streams. Water in the Rio

Grande is generally accessible only in the southeast and

southwest corners of the area. The water is saline during low

flows in winter and carries a heavy load of suspended sediment.

Some of the water is diverted for livestock.

Ground water is generally very deep in the Edwards-Trinity

Plateau aquifer in this area. The water in this aquifer is very

hard and has a median level of total dissolved solids of 773

parts per million (milligrams per liter). This aquifer provides

water for livestock, domestic use, and some limited irrigation.

Rio Grande valley fill deposits provide some ground water for

livestock, domestic use, and limited irrigation in this area. The

ground water is recharged by the river, so the water quality is

similar to that of the Rio Grande.

Soils

The dominant soil orders in this MLRA are Aridisols and

Entisols. Most of the soils are Calcids, Cambids, or Orthents.

They are well drained and generally are shallow and have a

skeletal particle-size class. They have a thermic or

hyperthermic soil temperature regime, an aridic soil moisture

regime, and carbonatic or mixed mineralogy. Rock outcrop

makes up a significant portion of the area. Shallow

Haplocalcids (Lozier series) and Torriorthents (Mariscal series)

formed on limestone hills. Shallow Petrocalcids (Upton series)

and very deep Haplocambids (Sanderson series) formed on

alluvial fans, uplands, and footslopes. Very deep Haplocalcids

(Reagan series) formed in nearly level to gently sloping valleys.

Biological Resources

This area supports a desert plant community of low shrubs

and short or mid grasses. Limestone hills and footslopes

support black grama, bush muhly, chino grama, fluffgrass, and

sideoats grama with a diverse shrub community, including

cacti, creosotebush, feather dalea, lechuguilla, mariola,

skeleton leaf goldeneye, and scattered juniper. Valleys and

narrow drainageways support grasses, such as black grama,

burrograss, cane bluestem, sideoats grama, tobosagrass, and

vine-mesquite. Shrubs in narrow drainageways include

fourwing saltbush, tarbush, and hackberry.

Some of the major wildlife species in this area are javelina,

coyote, fox, bobcat, raccoon, skunk, opossum, jackrabbit,

cottontail, bobwhite quail, scaled quail, white-winged dove, and

mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—private, 87%; Federal, 10%

Water—private, 2%

Other—private, 1%

Most of this MLRA is used for grazing and wildlife habitat.

The Federal land in the MLRA is in parks and recreation areas

along the Rio Grande.

The major soil resource concerns are the wind erosion and

water erosion caused by overgrazing. Conservation practices

on rangeland include reasonable stocking rates, proper grazing

use, timely deferment of grazing, and pasture rotation. 
of the United States 237

Figure 82A-1: Location of MLRA 82A in Land Resource Region I.

degrees F (18 to 19 degrees C). The freeze-free period averages

260 days and ranges from 245 to 270 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 21.2%; ground water, 0.5%

Irrigation—surface water, 68.6%; ground water, 9.8%

Other—surface water, 0.0%; ground water, 0.0%

The total withdrawals average 10 million gallons per day (38

million liters per day). About 10 percent is from ground water

sources, and 90 percent is from surface water sources. The

amount of water is limited throughout most of the area but is

abundant along perennial streams and in three major reservoirs

on the Colorado River. Only a small quantity of water in the

Llano and Colorado Rivers and in the three reservoirs is used

for public supply, livestock, or irrigation in this area. The rivers

are spring fed from the limestone aquifers outside this area and

have water of good quality. Surface runoff, however, brings in

salt loads, which degrade the quality of the water.

Nearly all of this area lacks principal aquifers. Ground water

is in valley fill deposits along the perennial streams in the area.

It is generally shallow. These deposits provide water for

livestock, domestic use, and some limited irrigation. The

quality of the ground water is similar to that of the surface

water.

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, Inceptisols, and Mollisols. Most of the soils are

Ustalfs, Ustepts, Orthents, or Ustolls. They are well drained and

range from deep to shallow. They have a thermic soil

temperature regime, an ustic soil moisture regime, and mixed

mineralogy. Rock outcrop makes up a significant portion of the

area. Deep and moderately deep Paleustalfs (Pedernales and

Castell series) formed on plains. Shallow and moderately deep

Haplustalfs (Click and Oben series) formed on the summits of

hills and ridges. Shallow Haplustepts (Keese series) and shallow

Ustorthents (Nebgen series) formed on the side slopes of hills

and ridges. Shallow Haplustolls (Harper series) and moderately

deep Argiustolls (Rumple series) formed on plains.

Biological Resources

This area supports a mixed oak savanna plant community of

live oak, post oak, and blackjack oak and mid and tall grasses,

such as little bluestem, sideoats grama, Indiangrass,

switchgrass, sand lovegrass, plains lovegrass, green sprangletop,

purpletop, pinhole bluestem, and plains bristlegrass. Forbs,

such as orange zexmania, bushsunflower, Engelmann’s daisy,

eastern end of the area and increases westward to 2,200 feet

(670 meters) on ridges.

The only Hydrologic Unit Area (identified by a four-digit

number) that makes up this MLRA is Lower Colorado-San

Bernard Coastal (1209). The San Saba River cuts across the

northwest corner of this area, and the Llano River drains the

central part. Lakes Buchanan, Lyndon B. Johnson, and Marbles

Falls, three major reservoirs on the Colorado River, are at the

eastern end of this area.

Geology

This area is underlain primarily by igneous, metamorphic,

and sedimentary rocks. Igneous and metamorphic outcrops

include the Valley Spring Gneiss, Packsaddle Schist, and Town

Mountain Granite of Precambrian age. Sedimentary rocks

include the Hickory Sandstone and Lion Mountain Sandstone of

Cambrian age and the Hensell Sand of Cretaceous age.

Holocene alluvium is on flood plains.

Climate

The average annual precipitation in this area is 24 to 31

inches (610 to 785 millimeters). The higher rainfall usually

occurs in the eastern part of the area. Most of the rainfall occurs

in spring and fall. The average annual temperature is 65 to 67
238 Major Land Resource Areas

83A—Northern Rio Grande Plain

This area is entirely in Texas (fig. 83A-1). It is south of San

Antonio. It makes up about 11,115 square miles (28,805 square

kilometers). The towns of Uvalde, Cotulla, and Hondo are in

the western part of the area, and Beeville, Goliad, and Kenedy

are in the eastern part. The town of Alice is just outside the

southern edge of the area. Interstate Highways 35 and 37 cross

this area. The Chase Field Naval Air Station is outside Beeville.

Physiography

This area is in the West Gulf Coastal Plain Section of the

Coastal Plain Province of the Atlantic Plain. This plain

generally is nearly level, but smooth hills and valleys are

gently rolling. The valleys are narrow to broad. The hills are

mostly in the eastern part of the area. Elevation ranges from 200

feet (60 meters) in the southeastern part of the area to 1,000 feet

(305 meters) in the northwestern part.

and trailing ratany, grow throughout the area. A mid grass

community, with scattered live oak and post oak occurring as

individual trees or in groves, grows on the shallow and more

droughty soils. The major grass species on these soils are

sideoats grama, meadow dropseed, pinhole bluestem, Arizona

cottontop, vine-mesquite, Texas wintergrass, and little bluestem.

Some of the major wildlife species in this area are whitetailed deer, javelina, coyote, fox, bobcat, raccoon, skunk,

opossum, jackrabbit, cottontail, turkey, bobwhite quail, scaled

quail, white-winged dove, and mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 4%

Grassland—private, 89%

Urban development—private, 3%

Water—private, 2%

Other—private, 2%

Almost all of this area is used for grazing and wildlife

habitat. A few areas are used as cropland. Small grains and

forage sorghum are the principal crops.

The major soil resource concern is the erosion caused

primarily by overgrazing. Conservation practices on rangeland

generally include reasonable stocking rates, proper grazing use,

timely deferment of grazing, and pasture rotation. The

important conservation practices on cropland are terraces,

grassed waterways, conservation tillage, and irrigation water

management. 

Figure 83A-1: Location of MLRA 83A in Land Resource Region I.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Nueces-Southwestern Texas Coastal (1211), 66 percent; Central

Texas Coastal (1210), 33 percent; and Rio Grande-Falcon

(1308), 1 percent. The Frio, Hondo, Leona, Medina, Nueces,

Atascosa, Sabinal, and San Antonio Rivers cross this area. The

Guadalupe River crosses the northeastern tip of the area.

Geology

Cretaceous limestone deposits underlie the northern edge of

this MLRA. Most of the MLRA, however, lies within the

coastal plain created when Cretaceous seas retreated towards

the present-day Gulf of Mexico throughout Tertiary time.

Lagoonal, estuarine, beach, and deltaic sediments were

deposited in a wide swath paralleling the current coastline of

Texas and other Gulf States. Fine textured sediment deposited

in lagoons became shale layers, and the coarser textured

sediments became sandstone layers. These Tertiary rocks are at

the surface in this MLRA, and they are progressively younger

from west to east. Several commercially mined lignite coal and

uranium ore seams occur in these sediments. Natural gas

production also occurs in the sediments. The sandstone layers

are present-day aquifers.
of the United States 239

Climate

The average annual precipitation is 21 to 37 inches (535 to

940 millimeters) in most of this area. Most of the rainfall occurs

as high-intensity, convective thunderstorms during the growing

season. The annual precipitation increases from southwest to

northeast. The typical storm pattern changes in the southern

part of the area, where most of the rainfall occurs as moderateintensity, tropical storms that produce large amounts of rain

during winter. Hurricanes from the Gulf of Mexico occasionally

trigger heavy rainfall early in autumn. The average annual

temperature is 67 to 72 degrees F (20 to 22 degrees C). The

freeze-free period averages 315 days and ranges from 275 to

350 days, increasing closer to the coast.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 2.4%; ground water, 2.0%

Livestock—surface water, 1.2%; ground water, 1.4%

Irrigation—surface water, 19.3%; ground water, 63.9%

Other—surface water, 4.8%; ground water, 5.0%

The total withdrawals average 415 million gallons per day

(1,570 million liters per day). About 72 percent is from ground

water sources, and 28 percent is from surface water sources. The

rainfall is adequate for rangeland grasses but marginal for

cultivated crops. High temperatures and high evaporation and

transpiration rates limit crop production. The Nueces River

provides some water for irrigation, and ponds provide some

water for livestock and for domestic use. Some irrigation and

public supply water (primarily for Corpus Christi, which is

outside this area) is obtained from large reservoirs in this area,

but most of the water used is ground water. The limited surface

water available in this area is suitable for almost all uses. The

level of total dissolved solids ranges from 300 to 500 parts per

million (milligrams per liter). During late summer, low flows in

the part of the San Antonio River below San Antonio consist

primarily of municipal and industrial waste discharges.

Deep wells provide water for irrigation, livestock, public

supply, and domestic use. The Balcones Fault Zone in the

Edwards limestone aquifer underlies the northern edge of this

area, and the Gulf Coast aquifer system underlies the eastern

edge. The Carrizo-Wilcox aquifer underlies most of the area.

Water from this aquifer is moderately hard and has a median

level of total dissolved solids of 369 parts per million

(milligrams per liter). Heavy pumping from this aquifer for

irrigation has caused more saline water to leak into the aquifer

from adjacent bedrock units. The Gulf Coast aquifer provides

water for both public supply and irrigation in this area. Its water

is very similar in quality to the water in the Carrizo-Wilcox

aquifer. Deeper wells in both these aquifers encounter soft water

where sodium is replacing calcium. Water from the Edwards

aquifer is used primarily for public supply, but some wells also

provide irrigation water. Much of the flow from the Frio, Leona,

and Medina Rivers is lost to this aquifer as they cross it, but

springs downstream from the seepage zone in the Balcones

Fault Zone add some surface flow back to those rivers. The

ground water in the Edwards aquifer is similar in quality to that

in the other aquifers but is much harder. Also, more wells in this

aquifer than in the others have nitrate levels exceeding the

national standard for drinking water.

Soils

The dominant soil orders in this MLRA are Alfisols,

Mollisols, and Vertisols. The soils in the area dominantly have

a hyperthermic soil temperature regime, an ustic soil moisture

regime, and mixed or smectitic mineralogy. A small area where

the soil temperature regime is thermic is in the northern part of

the MLRA. The soils are generally very deep, well drained or

moderately well drained, and loamy or clayey. Haplustalfs

(Duval series) formed in residuum on plains. Paleustalfs formed

in loamy sediments on uplands (Floresville and Wilco series);

in mixed loamy and clayey sediments on marine terraces,

stream terraces, and plains (Miguel and Papalote series); and in

residuum on uplands (Webb series). Argiustolls (Weesatche

series) formed in loamy sediments on uplands. Calciustolls

formed in alluvium on stream terraces and uplands (Knippa,

Olmos, and Uvalde series) and in loamy sediments on uplands

(Sarnosa series). Haplustolls (Odem series) formed in alluvium

on natural levees and low stream terraces. Paleustolls (Poteet

series) formed in alluvium in drainageways. Haplusterts

(Monteola and Montell series) and Gypsiusterts (Esseville

series) formed in clayey sediments on uplands.

Biological Resources

This area supports open grassland vegetation with scattered

mesquite, live oak, and other trees. Little bluestem, sideoats

grama, lovegrass tridens, fourflower trichloris, Arizona

cottontop, plains bristlegrass, and other mid grasses are

dominant on the deeper soils. These soils support a number of

forbs, including orange zexmania, catclaw sensitivebrier,

western indigo, and bushsunflower. Open grassland with

scattered low-growing brush, such as guajillo, blackbrush,

elbowbush, and kidneywood, characterize the shallower soils.

Arizona cottontop, sideoats grama, green sprangletop, and

twoflower trichloris are the dominant mid grasses on these soils.

Some of the major wildlife species in this area are whitetailed deer, coyote, bobcat, beaver, raccoon, cottontail, fox

squirrel, turkey, bobwhite quail, and mourning dove. The

species of fish in the area include largemouth bass, sunfish,

catfish, and crappie.
240 Major Land Resource Areas

83B—Western Rio Grande Plain

This area is entirely in Texas (fig. 83B-1). It makes up about

9,285 square miles (24,060 square kilometers). The border

towns of Del Rio, Eagle Pass, Laredo, and Zapata are in this

MLRA. Interstate 35 crosses the area just north of Laredo. The

Amistad National Recreation Area is just outside this MLRA,

northwest of Del Rio, and the Falcon State Recreation Area is

southeast of Laredo. Laughlin Air Force Base is just east of Del

Rio.

Physiography

This area is in the West Gulf Coastal Plain Section of the

Coastal Plain Province of the Atlantic Plain. The area consists

mainly of low hills with sandstone escarpments. Most of the

escarpments occur in the western half of the area. The area is

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 15%

Grassland—private, 81%

Urban development—private, 2%

Water—private, 1%

Other—private, 1%

About four-fifths of this area is rangeland grazed mainly by

beef cattle and wildlife. A large acreage is cultivated. Grain

sorghum, cotton, corn, wheat, and small grain for grazing are

the main crops. Some areas, mostly in the western part of the

MLRA, are used for irrigated vegetables. Hunting leases for

deer, quail, and mourning dove are an important source of

income.

The major soil resource concerns are maintenance of soil

quality and the condition of the soils, water erosion in areas

with a slope of more than 1 percent, and wind erosion. An

adequate quantity of good-quality irrigation water is a concern

in the western part of the area. A major management concern is

controlling the brush and cactus that invade the grasslands.

Conservation practices on rangeland and pasture generally

include prescribed grazing, fencing, development of watering

facilities, and nutrient and pest management. The important

conservation practices on cropland are conservation crop

rotations, crop residue management, grassed waterways,

contour farming and terraces (in areas with a slope of more than

1 percent), nutrient management, and pest management.

Sprinkler irrigation systems, irrigation water conveyance

pipelines, furrow diking, grassed waterways, and irrigation

water management are important conservation practices that are

used mainly on the cropland in the western part of the area. 

Figure 83B-1: Location of MLRA 83B in Land Resource Region I.

gently undulating and somewhat dissected by intermittent

streams. Elevation ranges from 165 feet (50 meters) in the

southeastern part of the area to 1,200 feet (365 meters) in the

northwestern part.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Nueces-Southwestern Texas Coastal (1211), 54 percent; Rio

Grande-Falcon (1308), 42 percent; and Lower Rio Grande

(1309), 4 percent. The Rio Grande forms the international

border between Texas and Mexico in this area.

Geology

Surficial Cretaceous limestone and shale deposits occur in

the northernmost part of this MLRA. Most of the MLRA,

however, lies within the coastal plain created when the

Cretaceous seas retreated towards the present-day Gulf of

Mexico throughout Tertiary time. Lagoonal, estuarine, beach,

and deltaic sediments were deposited in a wide swath

paralleling the current coastline of Texas and other Gulf States.

Fine textured sediment deposited in lagoons became shale

layers, and the coarser textured sediments became sandstone

layers. These Tertiary rocks are at the surface in this area, and

they are progressively younger from west to east. Several

commercially mined lignite coal seams occur in these
of the United States 241

sediments. Natural gas production also occurs in the sediments.

The sandstone layers are present-day aquifers. The Rio Grande

flows on the southwest side of the Rio Grande Embayment, a

structural feature that formed in Tertiary time when extension in

response to plate tectonics caused the formation of a rift zone.

This rift zone became a low-lying area that eventually was

occupied by the Rio Grande. Recent alluvial sediments are

adjacent to the Rio Grande.

Climate

The average annual precipitation is 18 to 25 inches (455 to

635 millimeters) in most of the area. It increases from north to

south. Most of the rainfall occurs as high-intensity, convective

thunderstorms during the growing season. The average annual

temperature is 67 to 73 degrees F (20 to 23 degrees C). The

freeze-free period averages 325 days and ranges from 285 to

365 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 4.5%; ground water, 4.5%

Livestock—surface water, 1.9%; ground water, 1.0%

Irrigation—surface water, 50.9%; ground water, 29.4%

Other—surface water, 2.9%; ground water, 4.8%

The total withdrawals average 185 million gallons per day

(700 million liters per day). About 40 percent is from ground

water sources, and 60 percent is from surface water sources. The

rainfall is adequate for the growth of rangeland grasses. In most

years it is inadequate for cropland because of saline soils, high

temperatures, and high evaporation and transpiration rates. The

Rio Grande is the major perennial stream in this area. Other

major streams flow intermittently. Two major reservoirs have

been constructed on the Rio Grande by the United States and

Mexico. The International Amistad Reservoir is just outside the

northern end of this area, and the International Falcon

Reservoir is just southeast of the town of Laredo. The water

quality in the Rio Grande is poor upstream from the

International Amistad Reservoir. It improves dramatically in the

area between the Amistad and Falcon Reservoirs. The median

level of total dissolved solids is about 500 parts per million

(milligrams per liter). The Rio Grande water is used for

irrigation in this area. The Choke Canyon Reservoir lies just

west of Three Rivers. Away from the valley of the Rio Grande,

ponds provide water for livestock, wildlife, domestic use, and

irrigation.

Deep wells provide water for livestock, domestic use, and

irrigation in this area. The Carrizo-Wilcox aquifer underlies the

central third of the area. Other than the Rio Grande valley fill,

there are no principal aquifers under the northern and southern

thirds of the area. Water from the Carrizo-Wilcox aquifer is

moderately hard and has a median level of total dissolved

solids of 369 parts per million (milligrams per liter). Heavy

pumping from this aquifer for irrigation has caused more saline

water to leak into the aquifer from adjacent bedrock units. Rio

Grande valley fill deposits provide some ground water for

irrigation in this area. The ground water is recharged by the

river, so its water quality is similar to that of the Rio Grande.

Soils

The dominant soil orders in this MLRA are Alfisols,

Aridisols, Inceptisols, Mollisols, and Vertisols. The soils in

the area have a hyperthermic soil temperature regime, an ustic

soil moisture regime, and mixed or smectitic mineralogy.

They generally are moderately deep to very deep, well drained

or moderately well drained, and loamy or clayey. Haplustalfs

(Brennan and Hebbronville series) formed in loamy sediments

on uplands. Natrustalfs (Brundage series) formed in alluvium

on stream terraces. Paleustalfs (Brystal series), Haplustepts

(Maverick series), and Haplargids (Pryor series) formed in

residuum on uplands. Petrocalcids (Kimbrough series)

formed in eolian deposits on plains and ridges. Calciustepts

(Copita series) formed in mixed colluvium and residuum on

uplands. Calciustolls (Elindio, Jimenez, and Uvalde series)

formed in alluvium on stream terraces. Haplusterts formed in

mixed alluvium and colluvium (Catarina series) and outwash

or alluvium (Montell series) on plains and in drainageways.

Biological Resources

This area supports open grassland vegetation with scattered

shrubs. Mid grasses, such as alkali sacaton, twoflower trichloris,

pink pappusgrass, white tridens, whiplash pappusgrass, and

vine-mesquite, are dominant on deep, clayey soils. Guayacan,

spiny hackberry, desert yaupon, and fourwing saltbush are the

principal shrubs. Bundleflower, bushsunflower, Texas varilla,

and other forbs make up a minor but significant part of the

plant communities. The more gravelly soils support semi-open

grassland vegetation of mid grasses interspersed with lowgrowing shrubs. Guajillo, blackbrush, and kidneywood are the

principal shrubs. Arizona cottontop, sideoats grama, pink

pappusgrass, pinhole bluestem, green sprangletop, and

tanglehead are the dominant grasses. Several species of forbs

grow on these soils, mainly bushsunflower, orange zexmania,

snoutbean, dalea, and gaura.

Some of the major wildlife species in this area are whitetailed deer, javelina, coyote, fox, bobcat, ringtail cat, beaver,

nutria, raccoon, skunk, opossum, jackrabbit, cottontail, turkey,

bobwhite quail, scaled quail, mourning dove, and whitewinged dove. The species of fish in the area include channel

catfish, black bass, and sunfish.
242 Major Land Resource Areas

83C—Central Rio Grande Plain

This area is entirely in Texas (fig. 83C-1). It makes up about

4,275 square miles (11,075 square kilometers). The towns of

Freer, George West, and Hebbronville are in this area. The town

of Alice is on the east edge of the area. U.S. Highways 59 and

281 cross the area.

Physiography

This area is in the West Gulf Coastal Plain Section of the

Coastal Plain Province of the Atlantic Plain. It is a nearly level

to gently undulating plain that is weakly dissected by

intermittent drainageways. The landscape features are

influenced by thin eolian deposits occurring as a surficial sand

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 3%

Grassland—private, 94%

Urban development—private, 2%

Water—private, 1%

Almost all of this area is rangeland grazed by beef cattle and

wildlife. About 3 percent of the area is cropland used mainly for

grain sorghum, small grain, cotton, and improved pasture.

Small grain generally is grazed for winter pasture. Watermelons,

cantaloupes, and onions are grown under irrigation in alluvial

areas along the Rio Grande. Hunting leases for deer, quail,

mourning dove, wild turkey, and javelina are an important

source of income.

The major soil resource concerns are maintenance of soil

quality and the condition of the soils, water erosion in areas

with a slope of more than 1 percent, and soil salinity. Wind

erosion also is a concern on sandy and loamy soils in areas

where irrigated cropland is left fallow. Soil moisture is a major

concern throughout most of the area. Locally, saline and alkali

soils are a land use problem. An adequate quantity of goodquality irrigation water is a concern along the Rio Grande. A

major management concern is controlling brush and cactus that

invade the native grasslands.

Conservation practices on rangeland and pasture generally

include prescribed grazing, fencing, development of watering

facilities, and nutrient and pest management. The important

conservation practices on cropland are conservation crop

rotations; irrigation systems, including micro-irrigation;

irrigation water conveyance pipelines; and irrigation water

management. 

Figure 83C-1: Location of MLRA 83C in Land Resource Region I.

sheet that covers most of the area. The eolian deposits moved

downwind from southeast to northwest along the prevailing

wind direction. Elevation ranges from 150 feet (45 meters) on

the east side of the area to 860 feet (260 meters) on the west

side.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Nueces-Southwestern Texas Coastal (1211), 82 percent; Rio

Grande-Falcon (1308), 14 percent; and Lower Rio Grande

(1309), 4 percent. The Nueces and Frio Rivers are the only

major streams in this area.

Geology

This area is underlain by Tertiary sediments that trend

generally parallel to the Texas Gulf Coast and are progressively

younger approaching the coastline (eastward). The western part

of the area is underlain by calcareous clays, claystones, and

friable sandstones with some beds of white volcanic ash in the

Jackson Group of Eocene age. The central part is underlain by

soft or weakly cemented siltstones, sandstones, and tuff in the

Catahoula Formation of Miocene age. The eastern part is

underlain by clays, sandy clays, and weakly cemented
of the United States 243

sandstones in the Fleming Formation of Miocene age and the

overlying Goliad Formation of Pliocene age. Recent alluvial

sediments are along the Nueces and Frio Rivers.

Climate

The average annual precipitation in this area is 21 to 29

inches (535 to 735 millimeters). Most of the rainfall occurs

during the growing season. Hurricanes from the Gulf of Mexico

trigger heavy rainfall in the area from time to time in late

summer and early fall. The average annual temperature is 70 to

73 degrees F (21 to 23 degrees C). The freeze-free period

averages 335 days and ranges from 305 to 365 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 4.4%; ground water, 31.1%

Livestock—surface water, 6.7%; ground water, 24.4%

Irrigation—surface water, 11.1%; ground water, 22.2%

Other—surface water, 0.0%; ground water, 0.0%

The total withdrawals average 4.5 million gallons per day

(17 million liters per day). About 78 percent is from ground

water sources, and 22 percent is from surface water sources. The

rainfall is adequate for the growth of rangeland vegetation.

Crop yields, however, are limited by periods of moisture stress

caused by high temperatures and high evaporation and

transpiration rates. Ponds provide water for livestock, domestic

use, wildlife, and some irrigation and public supply. The

surface water is generally of good quality and is suitable for

most uses. The precipitation that accompanies hurricanes and

major storms cannot be discharged by the small drainage

systems in the area. Local drainageways may be flooded for

days, maybe even weeks, following a major storm.

Deep wells provide water for livestock, domestic use,

wildlife, and some irrigation and public supply. The CarrizoWilcox aquifer system is beneath the northwest corner of the

area. Water from this aquifer is moderately hard and has a

median level of 369 parts per million (milligrams per liter) total

dissolved solids. The Gulf Coast aquifer system underlies most

of the area. It consists of a complex of young, interbedded

clays, silts, sands, and gravel. The water from this aquifer is

generally of good quality. It is hard and typically has 300 to

500 parts per million (milligrams per liter) total dissolved

solids. Deeper wells in both the Gulf Coast and Carrizo-Wilcox

aquifers encounter soft water where sodium is replacing

calcium. There are no principal aquifers in the southwestern

third of this area.

Soils

The main soil orders in this MLRA are Alfisols, Inceptisols,

Mollisols, and Vertisols. The dominant soils in this area are

Ustalfs, Ustolls, Ustepts, and Usterts. They are moderately deep

or deep and moderately coarse textured or coarse textured.

They have a hyperthermic soil temperature regime, an ustic soil

moisture regime, and carbonatic or mixed mineralogy.

Very deep, well drained Paleustalfs (Comitas, Nueces, and

Sarita series) formed in sandy sediments on sandy eolian plains.

Shallow and moderately deep, nearly level to gently sloping

Paleustalfs (Delmita and Randado series) have a strongly

cemented caliche horizon and formed on eolian plains in the

central and eastern parts of this area. Deep, moderately well

drained Paleustalfs (Delfina series) formed on loamy eolian

plains in the central and eastern parts of the area. Nearly level

to gently undulating Haplustalfs (Brennan and Hebbronville

series) formed on loamy eolian plains in the central and western

parts of the area. Shallow, well drained Calciustolls (Olmos

series) have an indurated caliche horizon and formed in

limestone alluvium in undulating areas. Deep, well drained

Calciustolls (Hidalgo series) formed in calcareous sediments in

nearly level to gently sloping areas. Very shallow, well drained

Calciustepts (Zapata series) have an indurated caliche horizon

and formed on plains in the western part of the area. Moderately

deep, well drained Calciustepts (Copita series) formed in clayey

sediments over sandstone bedrock in the western part of the

area. Deep, fine textured, well drained Haplusterts (Tordia

series) formed in sediments overlying weakly consolidated

shale, siltstone, or sandstone that contains volcanic ash. Deep,

fine textured, moderately well drained and somewhat poorly

drained Haplusterts (Coquat, Cochina, and Buchel series)

formed in clayey alluvium along rivers.

Biological Resources

This area supports prairie vegetation with a few scattered

trees and shrubs. The major species on deep soils that have a

surface layer of fine sand are tall and mid grasses, such as

seacoast bluestem, Indiangrass, crinkleawn, and tanglehead,

with a variety of perennial legumes and forbs. The species

commonly occurring on loamy soils in the central and eastern

parts of the area are mid grasses, such as Arizona cottontop,

fourflower trichloris, tanglehead, plains lovegrass, and pinhole

bluestem. Many forbs and low-growing shrubs, including

condalia, vine ephedra, and guajillo, also grow on these loamy

soils. Woody vegetation consists of mesquite, huisache, and a

few oak trees.

Some of the major wildlife species in this area are whitetailed deer, javelina, coyote, fox, bobcat, raccoon, skunk,
244 Major Land Resource Areas

83D—Lower Rio Grande Plain

This area is entirely in Texas (fig. 83D-1). It makes up about

2,500 square miles (6,475 square kilometers). The towns of

Brownsville, Edinburg, Harlingen, McAllen, and Raymondville

are in this area. U.S. Highways 77 and 281 terminate in

Brownsville and McAllen, respectively. The Santa Ana

National Wildlife Area is along the Rio Grande in this area.

Physiography

This area is in the West Gulf Coastal Plain Section of the

Coastal Plain Province of the Atlantic Plain. It is a broad,

nearly level alluvial plain. Drainageways are shallow and have

low gradients. Elevation ranges from about 15 feet (5 meters) in

opossum, jackrabbit, cottontail, turkey, bobwhite quail, whitewinged dove, and mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 7%

Grassland—private, 89%

Urban development—private, 2%

Water—private, 1%

Other—private, 1%

Almost all of this area is rangeland grazed by beef cattle and

wildlife. About 7 percent of the area is cropland used mainly for

grain sorghum, cotton, wheat, and small grains for grazing.

Some areas are irrigated. Hunting leases for deer, wild turkey,

quail, mourning dove, javelina, and exotic game animals are an

important source of income in this area.

The major soil resource concerns include wind erosion and

water erosion. They also include accessory soil minerals,

including salts, in some areas. Rangeland site suitability and

plant productivity, health, and vigor are major concerns because

of the invasion of brush and cactus.

Conservation practices on rangeland generally include brush

control, range planting, prescribed grazing management,

prescribed burning, firebreaks, fences, adequate water

distribution systems, and development of upland wildlife

habitat. The important conservation practices on cropland are

crop rotations, nutrient management, pest management, crop

residue management, and mulch tillage and/or no-till systems.

On the more sloping cropland, terraces and grassed waterways

may be needed, depending on the type of crop residue

management and tillage system being used. 

Figure 83D-1: Location of MLRA 83D in Land Resource Region I.

the eastern part of the area to about 600 feet (185 meters) in

the northwestern part. It is mainly less than 275 feet (85

meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Nueces-Southwestern Texas Coastal (1211), 73 percent, and

Lower Rio Grande (1309), 27 percent. The Rio Grande forms

the international boundary between the United States and

Mexico in this MLRA. The river flows into the Gulf of Mexico

just east of the MLRA.

Geology

Most of this area is on the coastal plain created when

Cretaceous seas retreated towards the present-day Gulf of

Mexico throughout Tertiary time. Lagoonal, estuarine, beach,

flood-plain, and deltaic sediments were deposited in a wide

swath paralleling the current coastline of Texas and other Gulf

States. Fine textured sediments deposited in lagoons became

shale layers, and the coarser textured sediments became

sandstone layers. The rocks at the surface in this area are

primarily alluvial sediments of the Goliad Formation of

Miocene age and the Beaumont Formation of Pleistocene age.
of the United States 245

Older sandstone layers below the alluvial sediments yield

saline ground water in this area. Recent alluvial sediments are

adjacent to the Rio Grande.

Climate

The average annual precipitation is 22 to 27 inches (560 to

685 millimeters) in most of this area. Most of the rainfall occurs

as low- to moderate-intensity, Pacific frontal storms during

winter. Hurricanes from the Gulf of Mexico occasionally trigger

heavy rainfall in late summer and early fall in this area. The

average annual temperature is 72 to 74 degrees F (22 to 23

degrees C). The freeze-free period averages 350 days and ranges

from 330 to 365 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 6.2%; ground water, 5.4%

Livestock—surface water, 0.1%; ground water, 0.1%

Irrigation—surface water, 40.5%; ground water, 37.3%

Other—surface water, 10.0%; ground water, 0.3%

The total withdrawals average 800 million gallons per day

(3,030 million liters per day). About 43 percent is from ground

water sources, and 57 percent is from surface water sources. The

rainfall is adequate for the growth of rangeland grasses. It is low

in the western and central parts of the area and marginal in the

eastern part. High temperatures and high evaporation and

transpiration rates limit crop production. The Rio Grande, the

only perennial stream in this area, provides water for irrigation

and public supply. Two major reservoirs on the Rio Grande

upstream from this area, the International Amistad and Falcon

Reservoirs, dramatically improve the water quality in the river.

The level of total dissolved solids can exceed 10,000 parts per

million (milligrams per liter) at times above the Amistad

Reservoir. The level is about 500 parts per million (milligrams

per liter) below the Falcon Reservoir. In the uplands away from

the valley of the Rio Grande, ponds provide water for livestock,

domestic use, and irrigation. Reservoirs have been constructed

on most of the larger, although intermittent, tributaries of the

Rio Grande. Many irrigation and drainage channels are

throughout this area.

Deep wells provide water for livestock, domestic use, public

supply, and irrigation. The ground water in the part of the Gulf

Coast aquifer beneath this area is typically more saline than

that in the rest of this aquifer. It has 1,000 to 1,500 parts per

million (milligrams per liter) total dissolved solids in the valley

of the Rio Grande. The national standard for total dissolved

solids in drinking water is 1,000 parts per million (milligrams

per liter). Water from the upper part of the aquifer is moderately

hard, but it becomes soft at greater depths as sodium displaces

calcium. As more water is pumped from this aquifer, even more

saline water at greater depths can move up into the pumping

zone.

Soils

The dominant soil orders in this MLRA are Alfisols,

Mollisols, Vertisols, and Inceptisols. The soils in the area have a

hyperthermic soil temperature regime, an ustic soil moisture

regime, and mixed or smectitic mineralogy. They are generally

very deep, well drained or moderately well drained, and loamy

or clayey. Haplustalfs (Brennan series) formed in mixed

colluvium and residuum on ridges. Paleustalfs (Delfina series)

and Calciustepts (McAllen series) formed in loamy sediments

on old terraces and uplands. Haplustolls (Laredo and Ramadero

series), Argiustolls (Racombes and Willacy series), and

Calciustolls (Hidalgo and Raymondville series) formed in

alluvium on deltas and stream terraces and in drainageways.

Haplusterts (Harlingen and Mercedes series) formed in

alluvium on stream terraces.

Biological Resources

The open grassland in this area supports mid prairie grasses

with scattered woody plants and some perennial forbs and

legumes on soils in the uplands. Twoflower and fourflower

trichloris, plains bristlegrass, and lovegrass tridens are among

the dominant grasses on these soils. Desert yaupon, spiny

hackberry, and blackbrush are the major woody plants. Tall and

mid grasses, such as switchgrass, giant sacaton, fourflower

trichloris, big sandbur, little bluestem, and southwestern

bristlegrass, are dominant in savanna plant communities on

bottom land. Hackberry, mesquite, elm, and palm trees are the

major woody plants. Forbs are important but minor components

of the plant communities.

Some of the major wildlife species in this area are whitetailed deer, javelina, coyote, fox, bobcat, raccoon, skunk,

opossum, jackrabbit, cottontail, turkey, bobwhite quail, scaled

quail, white-winged dove, and mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 54%

Grassland—private, 27%; Federal, 3%

Urban development—private, 11%

Water—private, 2%

Other—private, 3%

Most of this area is cropland or improved pasture that is

extensively irrigated. A large acreage is rangeland grazed

mainly by beef cattle and wildlife. The major crops are cotton,

grain sorghum, citrus, onions, cabbage, and other truck crops.

Almost all of the crops are grown under irrigation. Hunting

leases for white-tailed deer, quail, white-winged dove, and
246 Major Land Resource Areas

83E—Sandsheet Prairie

This area is entirely in Texas (fig. 83E-1). It makes up about

4,300 square miles (11,150 square kilometers). The towns of

Falfurrias, Premont, and Sarita are in this area. U.S. Highways

77 and 281 run through the area in a north-south direction.

Physiography

This area is in the West Gulf Coastal Plain Section of the

Coastal Plain Province of the Atlantic Plain. It is a nearly level

to undulating eolian sand sheet. The surface consists of small

mounds or elongated ridges and closed saline depressions

aligned from southeast to northwest in response to prevailing

southeasterly winds. These features result from the deposition

of windblown sand into elongated dunes and from erosion of

elongated blowouts or wind-eroded depressions. Native grasses

and live oaks have stabilized most of the dune ridges. Dunes

that have not been stabilized are active and move slowly to the

northwest during dry summer months. Elevation ranges from

sea level near the shore of the Gulf of Mexico in the eastern part

of the area to 920 feet (280 meters) in the western part of the

area.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Nueces Southwestern Texas Coastal (1211), 97 percent; Rio

Grande Falcon (1308), 2 percent; and Lower Rio Grande

(1309), 1 percent. This area has no major rivers.

Geology

Recent (Holocene) alluvium and wind-deposited sand sheet,

silt sheet, clay dune, and base-level plain sediments were

deposited on Pleistocene and Tertiary geologic formations in

this area. The eolian sediments conceal these formations in

mourning dove are an important source of income in the area.

The area has some urban land, mainly in the southern part.

The major soil resource concerns are soil quality and the

condition of the soils, salinity, subsurface drainage, water

erosion, wind erosion, and an adequate quality and quantity of

irrigation water. The major land use problems are saline soils

and inadequate subsurface drainage on cropland.

Conservation practices on cropland generally include

conservation crop rotations, nutrient management, pest

management, crop residue management, surface roughening,

irrigation systems, irrigation water conveyance pipelines, and

irrigation water management. Conservation practices on

rangeland include reasonable stocking rates, proper grazing use,

timely deferment of grazing, and pasture rotation. 

Figure 83E-1: Location of MLRA 83E in Land Resource Region I.

most of the area. These older formations include (from east to

west across the area) the Beaumont and Lissie Formations of

Pleistocene age, the Goliad Formation of Pliocene age, the

Catahoula Formation of Miocene age, and the Frio Formation

of Oligocene age. The soils in this MLRA formed during the

Holocene, but the duration of soil formation depended on

landform stability and the period when eolian deposition

ended. Soil formation initiated with sand dune stabilization.

Wind-deposited silts and fine sands of the Riviera Loess Sheet

are in the extreme northern part of the area. The soils in this part

of the area have a higher content of clay and salts, particularly

in the subsoil, than similar soils in other parts of the area.

Loamy dunes, locally referred to as clay dunes, are winddeflation deposits that border the western and northern margins

of relict lakes. They resulted from eolian deposition of sandsized aggregates of silt and clay particles that eroded from dry

lakebed sediments.

Climate

The average annual precipitation in this area is 22 to 28

inches (560 to 710 millimeters). Most of the rainfall occurs in

spring and fall. The average annual temperature is 71 to 73

degrees F (22 to 23 degrees C). The freeze-free period averages

345 days and ranges from 325 to 365 days.
of the United States 247

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 8.7%; ground water, 23.9%

Irrigation—surface water, 11.2%; ground water, 56.2%

Other—surface water, 0.0%; ground water, 0.0%

The total withdrawals average 9 million gallons per day (34

million liters per day). About 80 percent is from ground water

sources, and 20 percent is from surface water sources. The

rainfall is adequate for the growth of rangeland vegetation.

Crop yields, however, are limited by periods of moisture stress

caused by high evaporation and transpiration rates and in some

areas by salinity. Ponds provide water for livestock, limited

irrigation, and domestic use. This area does not have an

integrated stream drainage network. The small amount of

surface water in the area is somewhat saline and is not generally

suitable for most uses. The amount of rainfall that accompanies

hurricanes and major storms cannot be discharged by the small

drainage systems. Therefore, broad areas may be flooded for

weeks following a major storm.

Deep wells in the Gulf Coast aquifer system provide water of

fairly good quality for livestock, limited irrigation, and

domestic use. This aquifer consists of a complex of young,

interbedded clays, silts, sands, and gravel. The water is hard and

slightly saline. It typically has 1,000 to 1,500 parts per million

(milligrams per liter) total dissolved solids. Wells more than

500 feet deep encounter soft water where sodium is replacing

calcium.

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, and Inceptisols. Most of the soils are Ustalfs,

Psamments, Aqualfs, or Aquepts. They are deep or very deep

and are moderately coarse textured or coarse textured. They

have a hyperthermic soil temperature regime, an ustic soil

moisture regime, and mixed mineralogy. Very deep, excessively

drained Ustipsamments (Falfurrias series) formed on recently

stabilized sand dunes. Well drained Paleustalfs (Sarita and

Nueces series) formed in sandy sediments on the stabilized

parts of the sand-sheet landscape.

Natrustalfs, Natraqualfs, and Halaquepts are associated with

salt-affected areas near Laguna Madre and inland depressions

and flats. Deep, moderately well drained Natrustalfs (Palobia,

Quiteria, and Padrones series) have a thick surface layer of sand

and a sandy to loamy subsoil with redoximorphic features.

Deep, somewhat poorly drained Natraqualfs (Sauz series) and

very deep, poorly drained Halaquepts (Saucel series) formed on

nearly level, low coastal terraces adjacent to tidal flats.

Biological Resources

The dominantly open grassland in this area has a mixture of

mid and tall grasses and perennial forbs. Stable dunes support

live oaks in the form of thickets and large motts separated by

low-lying areas of grassland. Salt-affected, poorly drained or

very poorly drained soils are dominated by gulf cordgrass.

Seacoast bluestem, brownseed paspalum, tanglehead,

switchgrass, Indiangrass, snoutbean, and western indigo

dominate soils that formed in the thicker deposits of sand. Once

denuded, these sands are very difficult to revegetate. As

thickness of the sandy surface soil decreases to less than 20

inches (50 centimeters), fourflower trichloris, Arizona

cottontop, plains bristlegrass, hooded windmillgrass, and

partridge pea become more dominant and make up a major part

of the vegetation. A mixture of brush species also dominates the

soils as retrogression occurs.

Some of the major wildlife species in this area are whitetailed deer, javelina, coyote, fox, bobcat, raccoon, skunk,

opossum, jackrabbit, cottontail, turkey, bobwhite quail, whitewinged dove, and mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 5%

Grassland—private, 88%; Federal, 3%

Urban development—private, 1%

Water—private, 2%

Other—private, 1%

Most of this area is rangeland grazed by beef cattle and

wildlife. Some areas have been converted to pasture, which

generally is seeded to coastal bermudagrass or kleingrass.

Hunting leases for deer, wild turkey, quail, mourning dove,

white-winged dove, javelina, and numerous species of exotic

game are an important source of income in the area.

The major soil resource concerns are accessory soil minerals,

including salts, and rangeland site stability. Plant productivity,

health, and vigor and undesirable woody species and cactus,

which compete with adapted grassland species, are other major

concerns.

Conservation practices on rangeland generally include brush

control, range planting, prescribed grazing management,

prescribed burning, firebreaks, fencing, adequate water

distribution systems, and development of upland wildlife

habitat. 

249

Figure J-1: Location of Land Resource Region J.

J—Southwestern Prairies Cotton and

Forage Region

This region (shown in fig. J-1) is in Texas (78 percent),

Oklahoma (21 percent), and Kansas (1 percent). It makes up

59,700 square miles (154,695 square kilometers). It is in the

southern Great Plains. Most of the population in Texas, away

from the coast, lives in this region.

The northern and western parts of this region consist of

gently rolling to hilly uplands dissected by numerous streams,

and the rest of the region is mainly a nearly level to gently

sloping, dissected plain. The Arbuckle and Wichita Mountains

are in the northern part of the region.

Moderate precipitation is accompanied by moderately high

temperatures. The average annual precipitation ranges from 31

to 44 inches (785 to 1,120 millimeters). Most of the

precipitation falls in spring and summer. The average annual

temperature ranges from 62 to 67 degrees F (17 to 19 degrees

C). The freeze-free period ranges from 245 to 290 days,

increasing in length from north to south.

The total withdrawals of freshwater in this region average

about 4,935 million gallons per day (18,680 million liters per

day). About 86 percent is from surface water sources, and 14

percent is from ground water sources. In this heavily populated

region, about 62 percent of the water is used for municipal and

industrial supply and 28 percent is used for public supply.

The soils in this region are dominantly Mollisols, Entisols,

Alfisols, and Vertisols. The major soil suborders are Paleustalfs,

Haplustolls, Haplusterts, and Argiustolls. All of the soils in the

region have a thermic soil temperature regime, and most have

an ustic soil moisture regime. Mineralogy is dominantly mixed

or smectitic, but it is siliceous in the Cross Timbers area and

carbonatic on the Edwards Plateau, the central part of the

region.

About 98 percent of this region is privately owned. The

native vegetation consists mainly of grasses and scattered trees.

The areas of trees are concentrated in the Cross Timbers area.

Grasslands include mixtures of range, pasture, and improved

pasture. Grazing by beef cattle is the dominant land use in most

of the region, but hay, grain sorghum, and small grains are

grown in areas where the soils, topography, and moisture
250 Major Land Resource Areas

supply are favorable. Other locally important crops include

corn, cotton (fig. J-2), and peanuts. Pecans are grown on well

drained soils that are not flooded very often and are on the

higher terraces along many of the major rivers crossing the

region. Vegetables are grown in areas where irrigation water is

available.

The major resource concerns are overgrazing and the

invasion of undesirable plant species. Water erosion also is

a major resource concern, especially on cropland. Surface

compaction, moisture management, and maintenance of the

content of organic matter in the soils are additional concerns in

areas of cropland. 

Figure J-2: Cotton and prairie grasses in an area of Land Resource Region J.
of the United States 251

Figure 82B-1: Location of MLRA 82B in Land Resource Region J.

82B—Wichita Mountains

This area is entirely in southwestern Oklahoma (fig. 82B-1).

It makes up about 1,060 square miles (2,740 square kilometers).

The towns of Granite, Snyder, Medicine Park, and Meers are in

this MLRA. U.S. Highways 62 and 183 intersect in the area, and

Interstate 44 crosses the far eastern end. Quartz Mountain State

Park, the Wichita Mountains Wildlife Refuge, and the Fort Sill

Military Reservation are in this area.

Physiography

This area is in the Osage Plains Section of the Central

Lowland Province of the Interior Plains. The landscape of the

area is characterized by rugged hills and mountains made up

mainly of extrusive granite. Areas where the granite is at the

surface are nearly barren of vegetation. The faulted granite

blocks stand (at the highest point) about 1,000 feet (305

meters) above the surrounding plains. A smooth, nearly level to

moderately sloping erosional surface (pediment) is at the base

of the hills and mountains. Elevation ranges from 1,100 feet

(335 meters) to 2,020 feet (615 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows: RedWashita (1113), 64 percent, and Red Headwaters (1112), 36

percent. The North Fork of the Red River crosses the west end

of this area, and the Cache River drains the eastern part.

Geology

The surface geology of this MLRA is dominated by

intrusive igneous rocks (primarily granite) of Precambrian age

with associated limestone, sandstone, dolomite, chert, and shale

of Cambrian age. This area is underlain by both igneous and

sedimentary rocks in a structurally complex setting. Igneous

rocks primarily include granite, rhyolite, gabbro, and

anorthosite of Precambrian age. Sedimentary rocks include

limestone, sandstone, dolomite, and chert in the Lower

Arbuckle Formation (Timber Hills Group) of Cambrian age and

limestone with minor inclusions of sandstone, chert, dolomite,

and shale in the Upper Arbuckle Formation of Ordovician age.

A large outcrop known as the “Limestone Hills” is part of this

unit. The Meers Fault is a prominent geologic feature in this

area.

Climate

The average annual precipitation in this area is 26 to 31

inches (660 to 785 millimeters). The annual amounts may

fluctuate widely. Most of the rainfall occurs in spring and fall.

The average annual temperature is 59 to 62 degrees F (15 to 17

degrees C). The freeze-free period averages 230 days and ranges

from 220 to 245 days.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 31.3%; ground water, 18.8%

Irrigation—surface water, 31.3%; ground water, 18.8%

Other—surface water, 0.0%; ground water, 0.0%

The total withdrawals average 1.6 million gallons per day

(6.0 million liters per day). About 38 percent is from ground

water sources, and 62 percent is from surface water sources.

Water is scarce throughout the area because of the low and

erratic precipitation and few perennial streams. A few small

areas of irrigated cropland are served by the Luger-Altus

Irrigation District, which delivers water by canal from the Altus

Reservoir on the North Fork of the Red River. Naturally

occurring brine seeps make the river water saline.
252 Major Land Resource Areas

Ground water in this area is used for domestic purposes,

livestock, and some limited irrigation. Many springs and seeps

occur locally throughout the area. The Arbuckle-Timbered Hills

aquifer occurs in a very small area in Oklahoma. It is within this

MLRA, and it provides water for domestic use and irrigation.

The water in this aquifer is soft and has a median level of 772

parts per million (milligrams per liter) total dissolved solids.

Naturally high levels of chloride and fluoride preclude use of

the water for public supply. The only other principal aquifer in

this area is a valley fill deposit in the valley of the North Fork

of the Red River, in the northwest corner of the area. This

aquifer provides water primarily for livestock and some limited

irrigation. This ground water is similar in quality to the surface

water.

Soils

Most of the soils in this MLRA are Mollisols or Ustolls.

They have a thermic soil temperature regime, an ustic soil

moisture regime, and mixed mineralogy. Deep, nearly level to

moderately sloping Argiustolls (Lawton series) formed on

pediment surfaces. Very deep, moderately sloping to steep

Argiustolls (Brico series) formed in cobbly, granitic colluvium

on footslopes below granitic mountains. Shallow, very gently

sloping to steep Haplustolls (Kiti series) formed in limestone

residuum. Much of this area is covered by barren, granitic rock

outcrop that is highly fractured.

Biological Resources

This area supports mid and tall prairie grasses interspersed

with trees, particularly along fault lines. The diverse vegetation

includes big bluestem, Indiangrass, little bluestem, switchgrass,

sideoats grama, blue grama, buffalograss, post oak, blackjack

oak, maple, buckbrush, Jersey tea, goldenrod, scurfpea,

gayfeather, and Maximilian sunflower.

The major wildlife species in this area include white-tailed

deer, coyote, black-tailed jackrabbit, prairie dog, bobwhite

quail, ducks, and geese. The area has many manmade lakes that

provide good opportunities for recreational fishing.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 30%

Grassland—private, 38%; Federal, 22%

Forest—private, 3%; Federal, 1%

Urban development—private, 2%

Water—private, 3%

Other—private, 1%

Farms and ranches make up nearly all of the private land in

this area. Livestock grazing is the dominant land use, and most

of the rangeland is used for cow-calf operations. Cropland

makes up less than one-third of the area. Small grains, cotton,

and grain sorghum are the principal crops. Recreation and

tourism play a large part in the local economy. Most of the

Federal land in the area is used for recreation, grazing, or

military training and maneuvers.

The major soil resource concerns on cropland are control of

water erosion and conservation of soil moisture. The major

concern on rangeland is overgrazing. Conservation practices on

cropland generally include conservation tillage, pest

management, and irrigation water management. Conservation

practices on rangeland generally include reasonable stocking

rates, proper grazing use, and timely deferment of grazing. 

84A—North Cross Timbers

This area (shown in fig. 84A-1) is in Oklahoma (91 percent)

and Kansas (9 percent). It makes up about 7,705 square miles

(19,965 square kilometers). It occurs in two separate parts. The

towns of Ada, Norman, Shawnee, Sapulpa, and Sand Springs,

Oklahoma, are in the larger eastern part of the area. Some areas

of the western suburbs of Tulsa and the eastern suburbs of

Oklahoma City, Oklahoma, also are in this part. Interstate 44

and the Cimarron Turnpike (U.S. Highway 412) cross the

southern part of the area. Interstate 44 links Oklahoma City and

Tulsa. The western part of this area is west of Interstate 35 and

southwest of Oklahoma City. It includes the town of Duncan

and is crossed by Interstate 44. There are no large towns in the

part of this area in Kansas. The Osage Indian Reservation

(Osage County, Oklahoma) makes up a large acreage in the

center of the eastern part of this MLRA, just below the KansasOklahoma border.

The Cross Timbers ecosystem once covered about 30,525

square miles (79,105 square kilometers), extending from central

Texas, across Oklahoma, and into southeastern Kansas. Settlers

had difficulty making their way through this area because of the

tangled trees. The geographic name reflects this phenomenon.

The short oak trees are not very marketable for lumber, so many

areas have not been cleared for urban expansion or agriculture.

Therefore, the Cross Timbers is one of the least disturbed forest

types remaining in the eastern United States. The Cross Timbers

ecosystem has been subdivided into three subunits—North

Cross Timbers (MLRA 84A), West Cross Timbers (MLRA 84B),

and East Cross Timbers (MLRA 84C).

Physiography

This area is in the Osage Plains Section of the Central

Lowland Province of the Interior Plains. It is an area of rolling

to hilly uplands. Summits and divides on the hilltops are nearly
of the United States 253

Figure 84A-1: Location of MLRA 84A in Land Resource Region J.

level to strongly rolling and narrow to moderately broad.

Stream valleys are narrow and have steep gradients. Bedrock

outcrops occur on both the hilltops and hillsides. Elevation

ranges from 985 to 1,300 feet (300 to 395 meters). Local relief

is mostly 65 to 100 feet (20 to 30 meters), but the large valleys

are 165 feet (50 meters) or more below the adjacent uplands.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

North Canadian (1110), 24 percent; Neosho-Verdigris (1107),

24 percent; Red-Washita (1113), 19 percent; Lower Canadian

(1109), 18 percent; Lower Arkansas (1111), 6 percent; Lower

Cimarron (1105), 5 percent; Arkansas-Keystone (1106), 3

percent; and Red-Sulphur (1114), 1 percent. The major rivers

in the area include the Verdigris River in Kansas and the

Arkansas, Cimarron, and South Canadian Rivers in Oklahoma.

Many large reservoirs on tributaries to these rivers are in this

area.

Geology

Sandstones and shales of Permian age underlie the western

part of this area. The eastern part, including the part in Kansas,

is underlain by Pennsylvanian shale and sandstone. Pleistocene

stream terraces are a minor part of the area. They are alongside

the rivers.

Climate

The average annual precipitation is 30 to 40 inches (760 to

1,015 millimeters) in most of this area. It is closer to 30 inches

(760 millimeters) in the extreme western part of the area. The

maximum precipitation occurs in spring, and a small amount

occurs in winter. Most of the rainfall occurs as high-intensity,

convective thunderstorms in spring and summer. The annual

snowfall ranges from 12 inches (30 centimeters) in the northern

part of the area to 4 inches (10 centimeters) in the southern part.

The average annual temperature is 56 to 63 degrees F (13 to 17

degrees C). The freeze-free period averages 230 days and ranges

from 210 to 250 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 61.9%; ground water, 7.4%

Livestock—surface water, 9.4%; ground water, 1.8%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 17.2%; ground water, 2.2%

The total withdrawals average 180 million gallons per day

(680 million liters per day). About 12 percent is from ground

water sources, and 88 percent is from surface water sources. The

moderate and somewhat erratic rainfall is the source of water for

rangeland and cropland. Large reservoirs provide water for

cities and towns and for recreation and flood control. Farm

ponds are a major source of water for livestock.

In most of this area, shallow wells supply water for domestic

use, but ground water is scarce in areas where sandstone and

shale are near the surface. The Vamoosa-Ada aquifer underlies

most of the area. It is a Pennsylvanian-age sandstone. It

supplies soft to hard ground water primarily for public supply

and municipal and industrial uses. The median level of total

dissolved solids is 325 parts per million (milligrams per liter).

This water is suitable for drinking unless some local

contamination has resulted from oil and gas exploration and

development activities.

The Rush Springs aquifer underlies the separate western part

of this MLRA. It provides water primarily for irrigation. The

median level of total dissolved solids is 408 parts per million

(milligrams per liter). The water is very hard, but it can be used

for public supplies, except in local areas where the national

drinking water standards for chloride and sulfate are exceeded.
254 Major Land Resource Areas

84B—West Cross Timbers

This area (shown in fig. 84B-1) is in Texas (73 percent) and

Oklahoma (27 percent). It makes up about 6,165 square miles

(15,970 square kilometers). The city of Stephenville, Texas, is

at the southern end of this long, narrow MLRA. The towns of

Weatherford and Gainesville, Texas, are just outside the eastern

border of the area, in the middle and northern parts,

respectively. The part of this area in Oklahoma is between the

cities of Ardmore and Durant. Interstate 35 crosses the northern

part of the MLRA, and Interstate 20 crosses the middle. The

Tishomingo National Wildlife Refuge is in the northeast

corner of the area, in Oklahoma. The Lyndon B. Johnson

National Grasslands is in the part of this area in Texas, and

Dinosaur Valley State Park is on the southeastern boundary, in

Texas.

Physiography

Most of this area is in the Osage Plains Section of the

Central Lowland Province of the Interior Plains. The

southeastern part of the area is in the Central Texas Section of

the Great Plains Province of the Interior Plains, and the

northeast corner is in the West Gulf Coastal Plain Section of the

Coastal Plain Province of the Atlantic Plain. This MLRA is

mainly undulating and has low relief and numerous narrow

streams. The uplands are nearly level to rolling and are

moderately dissected. The northern part of the area has a higher

average slope gradient than the southern part and is gullied.

The southern part is nearly level to undulating and has been

significantly affected by wind erosion. Stream valleys are

narrow and have steep gradients. Elevation is mainly 1,000 to

1,300 feet (305 to 395 meters), but it is about 660 feet (200

meters) along the Red River. Local relief is mostly 10 to 50 feet

(3 to 15 meters).

Ground water is pumped from alluvial sediments and terrace

deposits along the major rivers that cross this area. This water is

used primarily for irrigation and domestic supply. It has a

slightly higher median level of total dissolved solids than the

water in the Rush Springs aquifer, but otherwise it is very

similar in quality.

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, Mollisols, and Inceptisols. The soils in the area

dominantly have a thermic soil temperature regime, an ustic or

udic soil moisture regime, and mixed, siliceous, or smectitic

mineralogy. They generally are shallow to very deep, somewhat

excessively drained to somewhat poorly drained, and loamy or

clayey. Haplustalfs formed in alluvium on stream terraces

(Dougherty and Konawa series) and in residuum on hills

(Newalla, Steedman, and Stephenville series). Hapludalfs

(Niotaze and Bartlesville series), Eutrudepts (Bigheart series),

and Haplustepts (Darnell series) formed in residuum on hills.

Paleustalfs (Harrah series) formed in colluvium on footslopes.

Ustifluvents (Pulaski series) and Hapludolls (Verdigris series)

formed in alluvium on flood plains. Paleudalfs (Prue series)

formed in colluvium and/or residuum on footslopes.

Biological Resources

This area supports an open stand of oak trees with an

understory of mid and tall grasses, forbs, and low woody plants.

Post oak and blackjack oak are the dominant tree species. Big

bluestem, little bluestem, Indiangrass, sunflower, and

lespedezas are the major species in the herbaceous understory.

Some of the major wildlife species in this area are whitetailed deer, coyote, fox, bobcat, badger, beaver, raccoon,

opossum, skunk, muskrat, jackrabbit, cottontail, mink, squirrel,

prairie dog, bobwhite quail, mourning dove, Mississippi kite,

and rattlesnake. The species of fish in the area include black

bass and channel catfish.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 7%

Grassland—private, 41%; Federal, 15%

Forest—private, 27%

Urban development—private, 6%

Water—private, 3%

Other—private, 1%

Much of this area is in farms and ranches. More than onehalf is rangeland, less than one-third is woodland, less than onetenth is pasture, and less than one-tenth is cropland. The Osage

Indian Reservation makes up almost all of the Federal land.

Some areas are used for urban development and for other

purposes. All of the areas of rangeland, woodland, and pasture

are grazed by beef cattle, but there are dairy cattle in some

areas. Small grains, grain sorghum, cotton, alfalfa, and other

hay crops are important in much of the area. Peanuts, tree fruits,

and vegetables are grown on a large acreage in the southern

part of the area.

The major soil resource concerns are water erosion, surface

compaction, moisture conservation, and conservation of organic

matter in the soils. Plant health, plant vigor, and noxious and

invading plants are the major management concerns on

grassland. Conservation practices on cropland generally

include terraces, grassed waterways, nutrient management,

grade-control structures, conservation tillage, and pest

management. Conservation practices on rangeland generally

include brush management, fencing, nutrient management,

proper grazing, and range planting. 
of the United States 255

Figure 84B-1: Location of MLRA 84B in Land Resource Region J.

units are exposed along the west side of the area and

successively younger units are exposed to the south and east.

From youngest to oldest, the four units in the Trinity Group are

the Antlers, Paluxy, Glen Rose, and Twin Mountains

Formations. The Antlers and Twin Mountains Formations

consist of alternating beds of sandstone, claystone, and

conglomerate. The Paluxy Formation is primarily fine grained

sandstone. The Glen Rose Formation is primarily a massive

limestone and dolomite unit at its base and grades upwards into

limestone, shale, marl, and gypsum beds. The Cretaceous

Fredericksburg Formation, an interbedded limestone, shale, and

clay unit overlying the Antlers Formation, is not an aquifer in

this area. Unconsolidated sands and gravel fill the valleys

along the Brazos and Trinity Rivers and their larger tributaries.

Climate

The average annual precipitation in most of this area is 26 to

42 inches (660 to 1,065 millimeters). It is 26 to 30 inches (660

to 760 millimeters) in the extreme southern part of the area. It

declines from east to west. Most of the rainfall occurs as highintensity, convective thunderstorms during summer. Almost 75

percent of the total annual precipitation falls during the freezefree period. The typical summer moisture deficit ranges from

about 7 to 10 inches (180 to 255 millimeters). Snow can occur

in this area, but it does not remain on the ground for long

periods. The average annual temperature is 62 to 66 degrees F

(17 to 19 degrees C). The freeze-free period averages 255 days

and ranges from 230 to 275 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 12.5%; ground water, 4.7%

Livestock—surface water, 9.8%; ground water, 1.7%

Irrigation—surface water, 31.0%; ground water, 13.0%

Other—surface water, 24.8%; ground water, 2.5%

The total withdrawals average 80 million gallons per day

(300 million liters per day). About 22 percent is from ground

water sources, and 78 percent is from surface water sources. The

moderate and somewhat erratic rainfall is the source of water for

pasture and crops. Farm ponds are a major source of water for

livestock. Local streams flow intermittently. A few large

reservoirs provide water for cities and towns and for recreation

and irrigation. The surface water is generally of good quality

and is suitable for almost all uses.

In most of this area, shallow wells supply water for domestic

use, but ground water is scarce in areas where sandstone and

shale are near the surface. The sandstone and carbonate layers

in the Trinity Group are the primary aquifers throughout the

area. Water in these units is very hard and has a median level of

total dissolved solids of 619 parts per million (milligrams per

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows: RedWashita (1113), 32 percent; Middle Brazos (1206), 24 percent;

Lower Brazos (1207), 20 percent; Trinity (1203), 19 percent;

Lower Colorado-San Bernard Coastal (1209), 3 percent; and

Red-Sulphur (1114), 2 percent. The Red River separates the

States of Oklahoma and Texas in this area. Lake Texoma, on the

Washita River, covers a significant portion of this area in

Oklahoma. The Brazos and Trinity Rivers cross the part of this

area in Texas. Denton Creek and many other streams forming

the headwaters of the Trinity River also are in the Texas part of

the area.

Geology

Cretaceous rocks of the Trinity Group are the primary

aquifers underlying the surface throughout the length of this

MLRA. Because of the southeast dip of these rocks, the oldest
256 Major Land Resource Areas

84C—East Cross Timbers

This area is entirely in north-central Texas (fig. 84C-1). It

makes up about 1,320 square miles (3,425 square kilometers).

The cities of Arlington, Cleburne, Denton, Gainesville, and Fort

Worth are in this MLRA. Interstate 20 crosses the area from east

to west, and Interstate 35E roughly forms the eastern boundary.

Ray Roberts State Park, on Lake Ray Roberts, and the

Eisenhower State Parks, on Lake Texoma, are two of the more

well known recreational areas in the MLRA.

Physiography

The boundary between two major physiographic divisions

occurs in this area. Most of the western half of the area is in the

Osage Plains Section of the Central Lowland Province of the

Interior Plains. The eastern half is in the West Gulf Coastal

liter). About 30 percent of the wells sampled in areas of these

aquifers showed levels of nitrate in excess of the national

drinking water standard of 10 parts per million (milligrams per

liter). Public supply, irrigation, and some industrial supply

wells occur throughout the area. Shallow wells for irrigation are

common in the southern part of the area, but the availability

and quantity of water vary greatly. Water levels have been

declining because of overuse, so future development of ground

water resources in this area is in jeopardy. Contamination from

nitrate sources is a problem in these shallow aquifers.

Another source of ground water in this area is the

unconsolidated deposits of sand and gravel that fill the major

river valleys. This calcium-magnesium, carbonate-bicarbonate

type of water is very hard, and almost half the samples tested

showed levels of total dissolved solids that exceeded 1,000 parts

per million (milligrams per liter). This aquifer also contained

nitrate at concentrations greater than 10 parts per million

(milligrams per liter) in 40 percent of the samples tested.

Soils

The dominant soil orders in this MLRA are Alfisols and

Entisols. The soils in the area dominantly have a thermic soil

temperature regime, an ustic soil moisture regime, and mixed or

siliceous mineralogy. They generally are deep or very deep,

well drained or moderately well drained, and loamy or clayey.

Ustifluvents (Pulexas series) formed in alluvium on flood

plains. Paleustalfs formed in residuum on plains (Chaney series)

and in sandy, loamy, and/or clayey sediments on uplands

(Demona, Duffau, Nimrod, Pedernales, Selden, and Windthorst

series). Paleudalfs (Bernow series) formed in loamy sediments

on uplands.

Biological Resources

This area supports savanna vegetation. Tall grasses are

interspersed with trees and underbrush. Little bluestem,

purpletop tridens, Indiangrass, switchgrass, big bluestem, sand

lovegrass, post oak, blackjack oak, elm, coralberry, greenbrier,

and elbowbush are the dominant species. Engelmann’s daisy,

Maximilian sunflower, and trailing wildbean are among the

numerous perennial forbs.

Some of the major wildlife species in this area are whitetailed deer, coyote, fox, bobcat, raccoon, skunk, opossum,

rabbit, armadillo, squirrel, quail, and mourning dove. The

species of fish in the area include largemouth bass, channel

catfish, and bream.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 12%

Grassland—private, 66%; Federal, 2%

Forest—private, 5%

Urban development—private, 10%

Water—private, 4%

Other—private, 1%

Most of this area is in farms and ranches. About 70 percent of

the area is native grass pasture, improved pasture, or

noncommercial oak forests that are used for grazing. Most of

the areas of pasture, rangeland, and woodland are grazed by

beef cattle, but dairy cattle are important in some areas.

Generally, the acreage of cropland is decreasing and that of

improved pasture is increasing. The main crops are peanuts,

grain sorghum, small grains, and forage sorghum. Improved

bermudagrass and other hay crops also are important in the

area. Locally, peaches, apples, pecans, and vegetables are

important crops. About one-tenth of the area is used for urban

development and other purposes.

The major natural resource concerns include wind erosion;

water erosion (gully, sheet, and rill erosion); streambank

erosion; plant productivity, health, and vigor; and water for

livestock.

Conservation practices on cropland generally include

nutrient and pest management, crop residue management,

critical area planting, development of ponds, and streambank

and shoreline protection. Conservation practices on pasture,

rangeland, and forestland generally include riparian forest

buffers, fencing, forage harvest management, brush

management, prescribed burning, and proper grazing use. 
of the United States 257

Figure 84C-1: Location of MLRA 84C in Land Resource Region J.

Geology

This area is underlain by interbedded sandstones and shales

in the Woodbine Formation of Cretaceous age. On this gently

sloping to rolling landscape, the more resistant sandstones form

ridges and hilltops and the more erodible sediments form side

slopes, hillsides, and valleys.

Climate

The average annual precipitation in this area is 34 to 41

inches (865 to 1,040 millimeters). Most of the rainfall occurs in

spring and fall. The average precipitation during the freeze-free

period is about 24 to 26 inches (610 to 660 millimeters). The

average annual temperature is 62 to 66 degrees F (17 to 19

degrees C). The freeze-free period averages about 265 days and

ranges from 255 to 280 days.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 15.2%; ground water, 9.6%

Livestock—surface water, 0.1%; ground water, 0.0%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 74.5%; ground water, 0.5%

The total withdrawals average 1,510 million gallons per day

(5,715 million liters per day). About 10 percent is from ground

water sources, and 90 percent is from surface water sources. The

moderate and somewhat erratic rainfall is generally sufficient

for quality native forage and for watering livestock. Also, it is

the major source of water for pasture and crops. Local streams

flow intermittently. Large reservoirs on the major streams

provide water for cities and towns. The lake water is used for

public supply, industry, and recreation. Farm ponds are a major

source of water for livestock. The surface water is generally of

good quality and is suitable for most uses.

In most of this area, shallow wells supply water for domestic

use. A few small irrigation wells supply a limited quantity of

water. Sandstone and carbonate layers in the Trinity Group are

the principal aquifers in this MLRA. The ground water in these

aquifers is very hard and has a median level of 619 parts per

million (milligrams per liter) total dissolved solids. About 30

percent of the samples from areas of these aquifers exceeded

the national drinking water standard for nitrate. Falling water

tables limit the use of this aquifer.

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, and Mollisols. They are moderately deep or deep,

medium textured to coarse textured, and moderately well

Plain Section of the Coastal Plain Province of the Atlantic

Plain. The area is characterized by gently sloping to rolling

uplands that are moderately dissected. Sandstone-capped hills

and ridges rise prominently above the surrounding landscape.

Stream valleys are narrow and have steep gradients. Elevation

ranges from about 500 to 1,000 feet (150 to 305 meters). Local

relief is mostly 3 to 50 feet (1 to 15 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Trinity (1203), 65 percent; Red-Washita (1113), 16 percent;

Middle Brazos (1206), 15 percent; and Red-Sulphur (1114),

4 percent. The Brazos, Red, and Trinity Rivers dissect the

MLRA. Lake Texoma, on the Red River, is in the northern part

of the area. Lakes Arlington, Grapevine, Lewisville, and Ray

Roberts are in the central part, on tributaries of the Trinity

River. Lake Aquilla is in the southern part of the MLRA, on a

tributary of the Brazos River.
258 Major Land Resource Areas

85—Grand Prairie

This area (shown in fig. 85-1) is in north-central Texas (83

percent) and south-central Oklahoma (17 percent). It makes up

about 10,400 square miles (26,955 square kilometers). It occurs

in two separate parts. The cities and towns of Belton, Cleburne,

Denton, Fort Worth, Gainesville, Killeen, and Weatherford,

Texas, and Ardmore and Sulphur, Oklahoma, are in this MLRA.

Interstate 35 crosses this area in both States, and Interstate 20

crosses Interstate 35 in Fort Worth, Texas. The Fort Hood

Military Reservation, most of Dinosaur Valley State Park, and

the eastern tip of the Lyndon B. Johnson National Grasslands

are in the part of this area in Texas. The Chickasaw National

Recreation Area is in the part in Oklahoma.

Physiography

The northern one-third of this area, in Oklahoma and Texas,

is in the Osage Plains Section of the Central Lowland Province

of the Interior Plains. The southern two-thirds is in the Central

Texas Section of the Great Plains Province of the Interior Plains.

This area is characterized by gently rolling to hilly, dissected

limestone plateaus and the adjacent gently sloping valleys.

Steep slopes commonly border the valleys along the major

streams that cross the area. The Arbuckle Mountains, in

southern Oklahoma, consist mainly of rugged hills and plateaus

with deeply dissected canyons and steep slopes bordering

valleys. Elevation ranges from 500 to 1,310 feet (150 to 400

meters) in most of the area, but it ranges from 1,310 to 1,650

feet (400 to 505 meters) in the Arbuckle Mountains.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Lower Brazos (1207), 32 percent; Middle Brazos (1206), 26

percent; Trinity (1203), 19 percent; Red-Washita (1113), 11

percent; Lower Colorado-San Bernard Coastal (1209), 6

percent; Red-Sulphur (1114), 4 percent; and Lower Canadian

(1109), 2 percent. The upper tributaries and reaches of the

Trinity and Brazos Rivers are in the part of this area in Texas.

The Colorado River is just outside the southern end of the area.

The Washita River is in the northern part of the area, in

drained to somewhat excessively drained. They have a thermic

soil temperature regime, an ustic soil moisture regime, and

smectitic, siliceous, or mixed mineralogy. Shallow and

moderately deep Haplustalfs (Rayex series) and Paleustalfs

(Birome series) formed on sandstone-capped hills and ridges.

Deep, well drained and moderately well drained Paleustalfs

(Callisburg and Crosstell series) formed in clayey material on

hillsides. Very deep, well drained, moderately permeable Ultic

Paleustalfs (Gasil and Konsil series) formed in sandy material

on hillsides. Very deep, well drained Arenic Paleustalfs (Silstid

series) and very deep, somewhat excessively drained

Psammentic Paleustalfs (Eufaula series) formed in sandy

material and have a thick, sandy surface layer. Deep, gently

sloping Paleustalfs (Bastrop and Bastsil series) formed on

stream terraces and footslopes on erosional remnants. Nearly

level Haplustolls (Whitesboro series) and Ustifluvents (Pulexas

and Bunyan series) formed on narrow flood plains along

tributaries.

Biological Resources

The native vegetation in this area consists of mid and tall

grasses interspersed with blackjack oak and post oak. The area

supports oak savanna vegetation with an understory of tall

grasses. Little bluestem, purpletop tridens, Indiangrass,

switchgrass, big bluestem, post oak, blackjack oak, elm,

coralberry, American beautyberry, bumelia, greenbrier, and

elbowbush are some of the dominant species. Engelmann’s

daisy, lespedezas, and trailing wildbean are among the

numerous perennial forbs.

Some of the major wildlife species in this area are whitetailed deer, javelina, coyote, fox, bobcat, raccoon, skunk,

opossum, jackrabbit, cottontail, turkey, bobwhite quail, scaled

quail, white-winged dove, and mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 13%

Grassland—private, 47%; Federal, 4%

Forest—private, 1%

Urban development—private, 25%

Water—private, 8%

Other—private, 2%

Most of this area is in farms and ranches, but sizable tracts in

the central part of the area are rapidly being converted to urban

uses. Some of the large tracts are being fragmented into smaller

ranches. Most of this rural area is used as improved pasture,

native grass pasture, or noncommercial oak forest and is grazed

mainly by beef cattle. Some areas are used for peanuts, small

grains, forage sorghum, fruits, or vegetables.

The major resource concerns are water quality, wind erosion,

and water erosion. Conservation practices that are important for

water quality are nutrient management and riparian buffers.

Also, proper management of septic tank absorption fields can

help to prevent pollution of the lakes in the MLRA. Wildlife

habitat is an important management objective of the landowners

in the MLRA. Warm-season improved pastures are established

to protect the area from erosion and to produce forage for

livestock. 
of the United States 259

Figure 85-1: Location of MLRA 85 in Land Resource Region J.

have been drilled into these folded sediments. This area has

significant exposures of granite, rhyolite, and gabbro of

Precambrian age.

Climate

The average annual precipitation in this area is 27 to 41

inches (685 to 1,040 millimeters). Most of the rainfall occurs in

spring and fall. The average precipitation during the freeze-free

period is 23 to 26 inches (585 to 660 millimeters). The average

annual temperature is 60 to 67 degrees F (16 to 19 degrees C).

The freeze-free period averages 260 days and ranges from 235

to 290 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 11.4%; ground water, 6.3%

Livestock—surface water, 2.1%; ground water, 0.3%

Irrigation—surface water, 14.0%; ground water, 5.0%

Other—surface water, 59.9%; ground water, 0.9%

The total withdrawals average 545 million gallons per day

(2,060 million liters per day). About 13 percent is from ground

water sources, and 87 percent is from surface water sources. In

most years the moderate and often erratic rainfall is adequate

for crops, pasture, and rangeland. Summer droughts commonly

reduce yields. The large rivers flow all year, and large reservoirs

provide municipal water and opportunities for recreation. Most

of the lakes and reservoirs within the Brazos River watershed

are brackish and used mainly for flood control and recreation.

Small farm ponds are an important source of water for farm use

(primarily livestock) and wildlife.

Deep ground water is abundant in the Cretaceous limestone

and sandstone layers of the Trinity Group aquifer in Texas. This

aquifer is at the surface throughout most of the part of this area

in Texas, and many seeps, springs, and local streams provide

water, mostly during spring and winter. The median level of

total dissolved solids in this ground water is 619 parts per

million (milligrams per liter), and the water is very hard. About

30 percent of all the wells tested in this aquifer have nitrate

concentrations that exceeded the national drinking water

standard of 10 parts per million (milligrams per liter). This

aquifer is heavily used for public supply, for municipal and

industrial water, and for irrigation. Some areas where water

levels have dropped significantly have begun to limit pumping

from this aquifer.

The Arbuckle-Simpson aquifer is in the part of this area in

Oklahoma. It supplies drinking water to domestic users but has

not been fully developed. The water is generally of good

quality, although chloride and fluoride levels exceed the

national standards for drinking water in some areas. The

median level of total dissolved solids in this ground water is

Oklahoma. Numerous flood-control and water-supply reservoirs

are throughout this area.

Geology

Most of this area is underlain by limestones and shales in the

Glen Rose Formation, Walnut Clay, Comanche Peak Limestone,

Edwards Limestone, Duck Creek Limestone, and the Kiamichi

Formation of Cretaceous age. These are mostly flat-lying

formations. The more resistant members form the summits of

ridges and hills, and the less resistant members form hillslopes

and valleys. There is a gentle southeastward dip of about 15

feet per mile (3 meters per kilometer). In the structurally

complex Arbuckle Mountains of southern Oklahoma,

outcropping rocks are primarily limestone, sandstone, dolomite,

quartzite, and chert. These units are exposed as alternating beds

of Paleozoic rocks that have been faulted, tilted, and deformed

to form a tombstone-like topography. Deep oil and gas wells
260 Major Land Resource Areas

369 parts per million (milligrams per liter), and the water is very

hard.

Soils

The dominant soil orders in this MLRA are Vertisols and

Mollisols. The soils generally have a thermic soil temperature

regime, an ustic soil moisture regime, and smectitic, carbonatic,

or mixed mineralogy. Moderately deep to very deep Haplusterts

(Crawford, Sanger, and Slidell series) have smectitic mineralogy

and typically formed in nearly level to gently sloping areas.

Very deep, moderately well drained Haplusterts (Branyon

series) have smectitic mineralogy and formed on stream

terraces. Shallow and very shallow, gravelly and stony

Calciustolls (Aledo and Purves series) formed over limestone

bedrock in gently sloping to steep areas. Moderately deep and

deep, well drained Calciustolls (Bolar and Denton series)

formed over limestone bedrock primarily in gently sloping

areas. Shallow Haplustolls (Eckrant series) with smectitic

mineralogy and shallow Ustorthents (Maloterre series) with

carbonatic mineralogy formed in limestone residuum in gently

sloping to moderately steep areas on ridges and plateaus.

Shallow Haplustepts (Brackett series) and shallow Calciustolls

(Real and Doss series) have carbonatic mineralogy and formed

in limestone residuum in sloping to steep areas. Shallow, nearly

level to sloping Argiustolls (Speck and Tarpley series) formed

over limestone bedrock on ridges and plateaus. Very deep, well

drained Haplustolls (Krum series), Calciustolls (Venus and

Lewisville series), and Argiustolls (Blanket series) formed on

stream terraces and the lower valley slopes. Very deep, well

drained Haplustolls (Frio, Bosque, and Gowen series) have

significant accumulations of organic matter and formed on

flood plains. Rock outcrop occurs along ridgetops throughout

the area.

In the Arbuckle Mountains of Oklahoma, most of the soils

are Ustolls, Ustalfs, or Ustepts. They have a thermic soil

temperature regime, an ustic soil moisture regime, and mixed,

siliceous, or smectitic mineralogy. Very shallow to deep, gently

sloping to steep Haplustolls (Kiti, Rayford, and Timhill series),

Haplustalfs (Bromide series), Argiustolls (Scullin series), and

Haplustepts (Travertine and Tussy series) formed on plateaus

and mountain slopes. Very deep, gently sloping Paleustalfs

(Bastrop and Gasil series) and Haplustalfs (Konawa series)

formed on stream terraces. Very deep, nearly level Haplustolls

(Dale series) and Ustifluvents (Yahola series) formed on flood

plains along the major drainageways. Rock outcrop occurs

throughout the Arbuckle Mountains.

Biological Resources

The native vegetation in this area consists of mid and tall

grasses interspersed with scattered oaks. Little bluestem,

Indiangrass, big bluestem, and switchgrass are typical species

on the deeper soils. Texas wintergrass, little bluestem, silver

bluestem, buffalograss, and sideoats grama, as well as scattered

shin oak, live oak, elm, ash, and juniper, are characteristic plant

species on shallow soils and on soils along escarpments. Areas

of deteriorated rangeland commonly have increased amounts of

short grasses, annuals, weeds, pricklypear, elm, mesquite, and

blueberry juniper.

The Arbuckle Mountains support mid and tall grasses.

Sideoats grama and little bluestem are the major species.

Indiangrass, big bluestem, switchgrass, hairy grama, dropseed,

and forbs are common. Sycamore and willow grow along

creeks. Prairie fires restrict the spread of sumac, skunkbush, and

other shrubs. Resource deterioration results in a higher

percentage of short grasses, annuals, pricklypear, and eastern

redcedar.

Some of the major wildlife species in this area are whitetailed deer, javelina, coyote, fox, bobcat, raccoon, skunk,

opossum, jackrabbit, cottontail, turkey, bobwhite quail, scaled

quail, white-winged dove, and mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 13%

Grassland—private, 71%; Federal, 4%

Forest—private, 2%

Urban development—private, 7%

Water—private, 2%

Other—private, 1%

Most of this area is in ranches, farms, and other private

holdings. The dominant land use is livestock grazing on

rangeland. A smaller acreage is used as cropland or improved

pasture. Many ranches are involved in wildlife management.

The major crops in the area are small grains and forage

sorghum, which are used as supplemental feed for livestock

and wildlife. Pastured areas support mainly improved

bermudagrass and kleingrass. Native pecan orchards are

common on flood plains. Deer and wild turkey hunting leases

are an important source of income in the southern part of the

area. Urban land is rapidly expanding adjacent to the major

cities.

The major resource concerns on cropland are encroachment

of woody species, maintenance of the content of organic matter

in the soils, conservation of soil moisture, and water erosion.

The major resource concerns on rangeland are overgrazing and

the invasion of undesirable plant species.

Conservation practices on cropland generally include grassed

waterways and terraces. Conservation practices on rangeland

include control of brush and invasive weeds, reasonable

stocking rates, and rotational grazing. 
of the United States 261

Figure 86A-1: Location of MLRA 86A in Land Resource Region J.

86A—Texas Blackland Prairie, Northern

Part

This area is entirely in Texas (fig. 86A-1). It makes up about

15,110 square miles (39,150 square kilometers). The cities of

Austin, Dallas, San Antonio, San Marcos, Temple, and Waco

are in this MLRA. Interstate 35, a major thoroughfare for

commerce and travel, traverses the length of the MLRA from

San Antonio to Dallas. Bergstrom, Randolf, and Lackland Air

Force Bases are in the southern end of this area. The Caddo

National Grasslands are in the northern part of the area.

Physiography

Almost all of this area is in the West Gulf Coastal Plain

Section of the Coastal Plain Province of the Atlantic Plain. The

west-central edge of the area is in the Central Texas Section of

the Great Plains Province of the Interior Plains. Most of this

MLRA is a nearly level to gently sloping, dissected plain.

Dissected areas with steeper slopes occur along entrenched river

and creek valleys. Broad meander belts are associated with the

major streams, and wide flood plains are flanked by nearly level

stream terraces. Elevation ranges from 300 to 600 feet (90 to

185 meters), increasing gradually from southeast to northwest.

Areas of hilly land are associated with the Austin Chalk

escarpment near the western edge of the area.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Trinity (1203), 39 percent; Lower Brazos (1207), 20 percent;

Red-Sulphur (1114), 14 percent; Central Texas Coastal (1210),

9 percent; Sabine (1201), 7 percent; Middle Brazos (1206), 6

percent; and Lower Colorado-San Bernard Coastal (1209), 5

percent. The headwaters of the Sabine and Sulphur Rivers are in

the northern end of this area. The Trinity and Brazos Rivers

cross the center of the area. The rivers in the south end of the

area include the Colorado, Lavaca, Guadalupe, and San Antonio

Rivers.

Geology

This area is underlain by chalk, claystone, marl, and shale in

the Eagle Ford Group, Austin Chalk, and the Navarro Group

(including the “Taylor marl”) of Cretaceous age. These

Cretaceous rocks are incised by several major stream systems.

Quaternary stream terraces and alluvium are associated with the

rivers, and drainage patterns are controlled by more resistant

Cretaceous bedrock.

Climate

The average annual precipitation is 30 to 46 inches (760 to

1,170 millimeters) in most of this area, but it is less than 30

inches in the southern tip. Most of the rainfall occurs in spring

and fall. The average precipitation during the freeze-free period

is about 24 to 26 inches (610 to 660 millimeters). The average

annual temperature is 63 to 69 degrees F (17 to 21 degrees C).

The freeze-free period averages about 280 days and ranges from

250 to 310 days. Average annual temperatures and the length of

the freeze-free period increase to the south.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 18.2%; ground water, 11.0%

Livestock—surface water, 0.5%; ground water, 0.3%

Irrigation—surface water, 1.3%; ground water, 0.6%

Other—surface water, 67.5%; ground water, 0.4%

The total withdrawals average 2,315 million gallons per day

(8,760 million liters per day). About 12 percent is from ground

water sources, and 88 percent is from surface water sources. In
262 Major Land Resource Areas

86B—Texas Blackland Prairie, Southern

Part

This area is in two separate parts in east-central Texas (fig.

86B-1). It makes up about 2,925 square miles (7,585 square

kilometers). The towns of Brenham, Caldwell, La Grange,

Schulenberg, Hallettsville, Bellville, and Navasota are in the

eastern part of this MLRA. A very small part of the Sam

most years the moderate rainfall is adequate for crops and

pasture, but summer droughts commonly reduce crop yields.

Large reservoirs on the major streams provide municipal water.

The water from the reservoirs is supplemented by some ground

water. The reservoirs not only provide water for public supply

and industry but also serve as recreational facilities. Small farm

ponds are an important source of water for farm use (primarily

livestock) and recreation. The surface water is of good quality

and is suitable for almost all uses.

Shallow ground water is scarce throughout this area, but

several areas obtain small quantities of ground water from

wells. Sandstone and carbonate layers in the Trinity Group are

the principal aquifers in the MLRA. This ground water is very

hard and has a median level of 619 parts per million (milligrams

per liter) total dissolved solids. About 30 percent of the samples

from this aquifer exceeded the national drinking water

standards for nitrate. Falling water tables limit the use of this

aquifer.

Soils

The dominant soil orders in this MLRA are Entisols,

Mollisols, and Vertisols. The soils are well drained or

moderately well drained and fine textured or medium textured.

They have a thermic soil temperature regime, an ustic soil

moisture regime, and smectitic, carbonatic, or mixed

mineralogy. Moderately deep to very deep, nearly level to

gently sloping Haplusterts (Branyon, Burleson, Heiden,

Houston Black, Dalco, Leson, and Fairlie series) formed on

uplands and stream terraces. Deep and very deep, gently

sloping to strongly sloping Haplusterts (Ellis, Ferris, and Vertel

series) formed on hillsides. Moderately deep to very deep,

gently sloping to moderately sloping Haplustolls (Austin,

Krum, Lott, and Stephen series) formed on side slopes and

stream terraces. Very deep, gently sloping Calciustolls

(Lewisville and Venus series) formed on stream terraces and

footslopes below hills and ridges. Shallow, gently sloping to

strongly sloping Ustorthents (Eddy series) formed on hillsides

and breaks. Very deep, nearly level to gently sloping

Haplustalfs (Wilson series) and Paleustalfs (Crockett and

Mabank series) formed on ancient stream terraces. Very deep,

nearly level Haplustolls (Gowen series) and Hapluderts

(Kaufman, Tinn, and Trinity series) formed on flood plains.

Biological Resources

This area supports mixed tall and mid prairie grasses. Little

bluestem is the dominant species. Indiangrass, big bluestem,

switchgrass, tall dropseed, silver bluestem, sideoats grama,

eastern gamagrass, and vine mesquite are the major herbaceous

species. The plant community has many forbs, such as prairie

clover, western ragweed, Maximilian sunflower, gayfeather,

rattlesnake master, and Indian plantain. Areas along the major

rivers and streams support savanna vegetation. Oak, elm,

cottonwood, hackberry, and pecan trees produce a canopy

cover of about 30 percent.

Some of the major wildlife species in this area are whitetailed deer, javelina, coyote, fox, bobcat, raccoon, skunk,

opossum, jackrabbit, cottontail, turkey, bobwhite quail, scaled

quail, white-winged dove, and mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 29%

Grassland—private, 48%; Federal, 1%

Forest—private, 2%

Urban development—private, 15%

Water—private, 3%

Other—private, 2%

Nearly all of this area is improved pasture, cropland, or

rangeland. Urban development is rapidly increasing adjacent to

the major cities. Cotton, corn, and grain sorghum are the major

crops. Other crops are small grains, soybeans, and hay. Native

and improved pecan orchards are common on the flood plains

where better drainage or less frequent flooding occurs. The

current land use trend is a decrease in the acreage of cropland

on the more sloping and eroded soils and an increase in the

acreage of improved pasture. The main kind of livestock is beef

cattle.

The major soil resource concerns are water erosion,

maintenance of the content of organic matter and productivity

of the soils, and management of soil moisture. Conservation

practices on cropland generally include terraces, grassed

waterways, buffer strips, crop residue management in reduced

till and no-till systems, and nutrient management. Conservation

practices on pasture and hayland generally include grazing

management systems, applications of the proper kinds and

amounts of fertilizer, and control of brush and weeds. The most

important conservation practice on rangeland is prescribed

grazing. Generally, cultural practices are not used to increase

forage production on the rangeland in this area. 
of the United States 263

Figure 86B-1: Location of MLRA 86B in Land Resource Region J.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Lower Brazos (1207), 53 percent; Central Texas Coastal (1210),

25 percent; Lower Colorado-San Bernard Coastal (1209), 12

percent; Galveston Bay-San Jacinto (1204), 6 percent; and

Trinity (1203), 4 percent. Some of the major rivers crossing the

eastern part of this area include the Navasota, Brazos, Colorado,

San Bernard, and Lavaca Rivers. Some of the major rivers

crossing the western part include the Navasota, Brazos, and

Yegua Rivers.

Geology

This area is underlain by calcareous clays, sandstones, and

marls in the Fleming Formation and Oakville Sandstone of

Miocene age and the Cook Mountain Formation of Eocene age.

These Tertiary sediments trend generally parallel to the Texas

Gulf Coast and are incised by several major stream systems.

Quaternary stream terraces and alluvium are associated with the

meander belts of the major streams.

Climate

The average annual precipitation in this area is 35 to 44

inches (890 to 1,120 millimeters). Most of the rainfall occurs in

spring and fall. The average precipitation during the freeze-free

period is about 29 inches (735 millimeters). The average annual

temperature is 66 to 69 degrees F (19 to 21 degrees C). The

freeze-free period averages about 295 days and ranges from 270

to 320 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 7.2%; ground water, 6.3%

Livestock—surface water, 3.3%; ground water, 1.7%

Irrigation—surface water, 52.6%; ground water, 26.3%

Other—surface water, 1.3%; ground water, 1.3%

Total withdrawals average 76 million gallons per day (290

million liters per day). About 36 percent is from ground water

sources, and 64 percent is from surface water sources. In most

years the moderate rainfall is adequate for crops and pasture;

however, summer droughts commonly reduce crop yields. Large

reservoirs on the major streams provide some municipal water.

The water from these reservoirs is supplemented by some

ground water. The reservoirs primarily provide water for

irrigation, but they are also used for recreation. Small farm

ponds are an important source of water for farm use (primarily

livestock) and recreation. The surface water is of good quality

and is suitable for almost all uses.

Houston National Forest is in the northern tip of the area. The

towns of Lincoln, Hogg, Benchley, and Normangee are in the

separate western part of this area. Interstate 10 and U.S.

Highways 77 and 290 cross various parts of this MLRA.

Physiography

This area is in the West Gulf Coastal Plain Section of the

Coastal Plain Province of the Atlantic Plain. Most of the area is

a nearly level to gently sloping, dissected plain. Dissected areas

with steeper slopes occur along entrenched river and creek

valleys. Broad meander belts are associated with major streams,

and wide flood plains are flanked by nearly level stream

terraces. Elevation ranges from 200 to 600 feet (60 to 185

meters), increasing gradually from southeast to northwest. Hilly

areas are associated with the more deeply eroded areas adjacent

to the major streams.
264 Major Land Resource Areas

The principal source of ground water in the eastern part of

this area is the Oakville Sandstone, which is underlain by

impermeable clays. This unit is part of the Gulf Coast aquifer

system, which consists of a complex of young, interbedded

clays, silts, sands, and gravel. The water from this aquifer is

generally of good quality. It is hard and typically contains 300

to 500 parts per million (milligrams per liter) total dissolved

solids. The separate western part of this area obtains its ground

water from the Carrizo-Wilcox aquifer system. The water from

this aquifer is moderately hard and contains a median level of

369 parts per million (milligrams per liter) total dissolved

solids. Where this aquifer is pumped heavily for irrigation,

more saline water from the adjacent aquifers may move into it.

Deeper wells in both the Gulf Coast and the Carrizo-Wilcox

aquifers encounter soft water where sodium is replacing

calcium.

Soils

The dominant soil orders in this MLRA are Vertisols,

Inceptisols, Mollisols, and Entisols. The soils are deep or very

deep, well drained or moderately well drained, and medium

textured to fine textured. They have a thermic soil temperature

regime, an ustic soil moisture regime, and smectitic, mixed, or

carbonatic mineralogy.

Very deep, moderately well drained Haplusterts

(Bleiblerville, Dimebox, and Luling series) have smectitic

mineralogy and formed on nearly level to gently sloping

uplands. Some very deep, moderately well drained Haplusterts

(Burleson series) have smectitic mineralogy and formed on

stream terraces. Very deep, moderately well drained Calciusterts

(Frelsburg and Latium series) have smectitic mineralogy and

formed in very gently sloping to moderately steep areas. Very

deep Calciustolls (Brenham series) formed in very gently

sloping to moderately sloping areas associated with silty clays

and marls in the Fleming Formation. Moderately deep

Calciustolls (Carbengle series) and shallow Haplustolls (Renish

series) formed in gently sloping to moderately steep areas

associated with Oakville Sandstone escarpments. Moderately

well drained, fine textured Argiustolls (Benchley series) and

Paleustalfs (Crockett series) have vertic properties and smectitic

mineralogy and formed on ridges. Very deep, moderately well

drained, fine textured Paleustalfs (Mabank series) and

Haplustalfs (Wilson series) have a seasonal high water table and

smectitic mineralogy and formed on stream terraces. Fineloamy Argiustolls (Smithville series) and fine-silty Haplustolls

(Bergstrom series) have significant accumulations of organic

matter and formed on flood plains and low stream terraces.

Fine-silty Haplustepts (Weswood series), coarse-loamy

Ustifluvents (Yahola series), and coarse-silty Ustifluvents

(Coarsewood series) have an irregular decrease in content of

organic matter with depth and formed on flood plains. Clayey,

very slowly permeable Haplusterts (Ships series) also formed on

flood plains.

Biological Resources

This area supports mixed tall and mid prairie grasses. Little

bluestem is the dominant species. Additional herbaceous

species include sedges, Virginia and Canada wildrye, rustyseed

paspalum, beaked panicum, switchgrass, Indiangrass, big

bluestem, eastern gamagrass, sideoats grama, and vine

mesquite. Many forbs grow in the area, including tickclover,

trailing wildbean, lespedezas, and gayfeather. Areas along the

major rivers and streams support a savanna plant community.

Oak, elm, cottonwood, hackberry, and pecan trees produce a

canopy cover of about 30 percent.

Some of the major wildlife species in this area are whitetailed deer, javelina, coyote, fox, bobcat, raccoon, skunk,

opossum, jackrabbit, cottontail, turkey, bobwhite quail, scaled

quail, white-winged dove, and mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 9%

Grassland—private, 80%

Forest—private, 3%

Urban development—private, 4%

Water—private, 2%

Other—private, 2%

Pasture and rangeland make up about 80 percent of this area.

Cotton, corn, and grain sorghum are the major crops. Other

important crops are small grains, soybeans, and hay. Native and

improved pecan orchards are common on flood plains where

better drainage or less frequent flooding occurs. The current

land use trend is a decrease in the acreage of cropland on the

more sloping and eroded soils and an increase in the acreage of

improved pasture. The main kind of livestock is beef cattle.

The major soil resource concerns are water erosion,

maintenance of the content of organic matter and productivity

of the soils, and management of soil moisture. Conservation

practices on cropland generally include terraces, grassed

waterways, buffer strips, crop residue management in reduced

till and no-till systems, and nutrient management. Conservation

practices on pasture and hayland generally include grazing

management systems, applications of the proper kinds and

amounts of fertilizer, and control of brush and weeds. The most

important conservation practice on rangeland is prescribed

grazing. Generally, cultural practices are not used to increase

forage production on the rangeland in this area. 
of the United States 265

Figure 87A-1: Location of MLRA 87A in Land Resource Region J.

87A—Texas Claypan Area, Southern Part

This area is entirely in south-central Texas (fig. 87A-1). It

makes up about 10,535 square miles (27,295 square

kilometers). The towns of Ennis, Fairfield, Groesbeck, Franklin,

Centerville, Madisonville, Rockdale, Bryan, College Station,

Bastrop, Giddings, Luling, and Gonzales are in this MLRA.

Interstate 45 crosses the northern part of the area, and Interstate

10 crosses the southern part. A number of State parks are

throughout this area. They are commonly associated with

reservoirs.

Physiography

This area occurs in the West Gulf Coastal Plain Section of

the Coastal Plain Province of the Atlantic Plain. It is a nearly

level to gently sloping plain that is dissected by broad river

systems. Gently sloping uplands merge into narrow valleys that

have sloping valley walls. Large rivers with broad, long valleys

cross the area. Elevation ranges from 200 to 750 feet (60 to 230

meters), increasing gradually from south to north. Slopes

generally range from 1 to 8 percent.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Lower Brazos (1207), 39 percent; Trinity (1203), 25 percent;

Central Texas Coastal (1210), 21 percent; Lower Colorado-San

Bernard Coastal (1209), 13 percent; and Nueces-Southwestern

Texas Coastal (1211), 2 percent. From north to south, the major

rivers crossing this area are the Trinity, Navasota, Brazos,

Colorado, Lavaca, and Guadalupe Rivers. A number of large

reservoirs are in the area.

Geology

This area is underlain by fluviodeltaic and marine sediments

of Tertiary age. Tertiary units include the Wilcox Group,

Carrizo Sand, Reklaw Formation, Queen City Sand, Weches

Formation, Sparta Sand, and Yegua Formation of Eocene age;

the Jackson Group of Eocene and Oligocene age; and the

Catahoula Formation of Miocene age. Sediments in these

Tertiary units consist of interbedded sandstone, siltstone, and

shale and unconsolidated to weakly coherent sands, silts, and

clays. The boundaries of these Tertiary sediments trend

generally parallel to the Texas Gulf Coast and are incised by

several major stream systems. Quaternary stream terraces and

alluvium are associated with the meander belts of the major

rivers.

Climate

The average annual precipitation in this area is 27 to 45

inches (685 to 1,145 millimeters). Most of the rainfall occurs in

spring and fall. The average precipitation during the freeze-free

period is about 30 inches (760 millimeters). The average annual

temperature is 64 to 70 degrees F (18 to 21 degrees C). The

freeze-free period averages about 285 days and ranges from 260

to 310 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 13.2%; ground water, 14.6%

Livestock—surface water, 5.2%; ground water, 2.6%

Irrigation—surface water, 38.1%; ground water, 20.5%

Other—surface water, 2.9%; ground water, 2.9%

The total withdrawals average 170 million gallons per day

(645 million liters per day). About 41 percent is from ground

water sources, and 59 percent is from surface water sources. In

most years the moderate rainfall is adequate for crops and

pasture; however, summer droughts commonly reduce yields.
266 Major Land Resource Areas

Large reservoirs on the major streams provide municipal and

irrigation water and also serve as recreational facilities. Ponds

provide water for farm use. The surface water is generally of

good quality and is suitable for almost all uses.

Ground water in this area is used for domestic purposes, for

livestock, and for some irrigation. The principal source of the

ground water is the Oakville Sandstone, which is underlain by

impermeable clays. This unit is part of the Gulf Coast aquifer

system, which consists of a complex of young, interbedded

clays, silts, sands, and gravel. The water in this aquifer is

generally of good quality. It is hard and typically contains 300

to 500 parts per million (milligrams per liter) total dissolved

solids. Deep wells in the Gulf Coast aquifer can encounter soft

water where sodium is replacing calcium.

Soils

The dominant soil orders in this MLRA are Alfisols,

Vertisols, Mollisols, and Entisols. The soils are very deep to

moderately deep and are somewhat excessively drained to

somewhat poorly drained. They have a thermic soil temperature

regime, an ustic soil moisture regime, and smectitic, siliceous,

or mixed mineralogy.

Moderately well drained and well drained, fine textured

Paleustalfs (Arol, Chazos, Edge, Gredge, Shiro, and Singleton

series) border on a udic soil moisture regime. Moderately well

drained, very slowly permeable, fine textured Paleustalfs

(Axtell, Crockett, Normangee, Zack, and Zulch series) border

on a udic soil moisture regime and have vertic properties. Very

deep, very slowly permeable, fine textured Paleustalfs (Lufkin,

Mabank, and Tabor series) have vertic properties and a seasonal

high water table. Moderately deep and very deep, fine textured

Paleustalfs (Burlewash, Falba, and Rosanky series) formed over

weakly cemented sandstone bedrock. Very deep, moderately

well drained, fine textured Paleustalfs (Rader and Straber series)

have a perched water table. Very deep, coarse textured, gently

sloping Paleustalfs (Demona, Robco, Silstid, and Tremona

series) have a sandy surface layer and formed in nearly level to

sloping areas. Deep, moderately well drained, coarse textured

Paleustalfs (Ellen series) formed on stream terraces. Very deep,

well drained, coarse textured Paleustalfs (Padina and Faula

series) and Quartzipsamments (Arenosa series) have a thick,

sandy surface layer and a sandy subsoil. Very deep, fine

textured, nearly level to gently sloping Haplusterts (Burleson

and Lexton series) formed on terraces and uplands. Very deep

and deep, medium textured, gently sloping Ultic Paleustalfs

(Gasil and Silawa series) and Udic Paleustalfs (Margie series)

formed in gently sloping areas.

Very deep, medium textured Haplustolls (Bergstrom, Gowen,

Smithville, and Whitesboro series) formed on flood plains and

low terraces. Very deep, fine textured Hapluderts (Trinity and

Ships series), Endoaquerts (Gladewater series), and Hapluderts

(Zilaboy series) formed on flood plains. Deep, coarse textured

and medium textured Ustifluvents (Yahola series), Udifluvents

(Hatliff series), Fluvaquents (Nahatche series), and Haplustepts

(Sandow, Uhland, and Weswood series) also formed on flood

plains.

Biological Resources

This area supports oak savanna vegetation. Little bluestem

is dominant on most sites. Little bluestem and beaked panicum

are dominant on poorly drained soils. Indiangrass, brownseed

paspalum, beaked panicum, switchgrass, and big bluestem grow

throughout the area. The woody species are dominantly post

oak and blackjack oak. The area supports a wide variety of

forbs, legumes, shrubs, and woody vines, such as dayflower,

spiderwort, bundleflower, lespedezas, sensitivebrier, hackberry,

hawthorn, yaupon, elbowbush, greenbrier, and honeysuckle.

Some mixed pine-hardwood forests are in the southwestern part

of the area. Hardwood forests of oak, elm, pecan, and other

species are on bottom land.

Some of the major wildlife species in this area are whitetailed deer, javelina, coyote, fox, bobcat, raccoon, skunk,

opossum, jackrabbit, cottontail, turkey, bobwhite quail, scaled

quail, white-winged dove, and mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 7%

Grassland—private, 79%; Federal, 1%

Forest—private, 4%

Urban development—private, 5%

Water—private, 2%

Other—private, 2%

Most of the farmland in this area is used for pasture and

livestock grazing. Most of the pastured areas formerly were

cultivated. About one-half of present-day pasture supports

improved grasses that are fertilized. Urban land is expanding in

several areas. Although significant areas of rangeland have

been overgrazed, conservation efforts are improving the

rangeland condition. The cropland in the area is used primarily

for corn. Other important crops are cotton, peanuts, hay, and

truck crops.

The major soil resource concerns are water erosion,

maintenance of the content of organic matter and productivity

of the soils, and management of soil moisture.

Conservation practices on cropland generally include

reduced till or no-till systems, crop residue management, and

nutrient management. Conservation practices on pasture and

hayland include grazing management, applications of the

proper kinds and amounts of fertilizer and lime, and control of

brush and weeds. The most important conservation practice on

rangeland is prescribed grazing. Generally, cultural practices

are not used to increase forage production on the rangeland in

this area. 
of the United States 267

Figure 87B-1: Location of MLRA 87B in Land Resource Region J.

87B—Texas Claypan Area, Northern Part

This area (shown in fig. 87B-1) is in northeastern Texas (79

percent) and southeastern Oklahoma (21 percent). It makes up

about 4,480 square miles (11,610 square kilometers). The towns

of Greenville, Sulphur Springs, Paris, Mount Vernon, Canton,

and Athens, Texas, and Durant, Oklahoma, are in this MLRA.

Interstates 30 and 20 and U.S. Highways 69, 70, 80, and 82

cross the area. The Caddo National Grasslands is in the north

end of the area.

Physiography

This area is in the West Gulf Coastal Plain Section of the

Coastal Plain Province of the Atlantic Plain. It is a nearly level

to gently sloping, dissected plain. Dissected areas with steeper

slopes occur along entrenched river and creek valleys. Broad

meander belts are associated with the major streams, and wide

flood plains are flanked by nearly level stream terraces.

Elevation ranges from 250 to 750 feet (75 to 230 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows: RedSulphur (1114), 66 percent; Sabine (1201), 21 percent; Trinity

(1203), 6 percent; Neches (1202), 4 percent; and Red-Washita

(1113), 3 percent. The border between Oklahoma and Texas is

formed by the Red River in this MLRA. The Sulphur and

Sabine Rivers cross the part of this area in Texas. Lake Texoma

forms the northwest corner of the MLRA.

Geology

This area is underlain by unconsolidated to weakly coherent

marine sands, silts, and clays, mainly in the Wilcox Group of

Eocene age. The boundaries of these Tertiary sediments trend

generally parallel to the Texas Gulf Coast and are incised by

several major stream systems. Quaternary stream terraces and

alluvium are associated with these meander belts.

Climate

The average annual precipitation is 39 to 45 inches (990 to

1,145 millimeters) in most of this area, but it can be as much as

49 inches (1,245 millimeters) in the northeast corner. Most of

the rainfall occurs in spring and winter. The average annual

temperature is 62 to 66 degrees F (17 to 19 degrees C). The

freeze-free period averages 260 days and ranges from 245 to

275 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 37.8%; ground water, 31.6%

Livestock—surface water, 9.3%; ground water, 2.9%

Irrigation—surface water, 1.8%; ground water, 4.4%

Other—surface water, 7.0%; ground water, 5.3%

The total withdrawals average 57 million gallons per day

(215 million liters per day). About 44 percent is from ground

water sources, and 56 percent is from surface water sources.

Precipitation, supplemented by ponds and small reservoirs, is

the main source of water for agricultural use. Summer rainfall is

erratic, and in most years crop yields are affected by reduced

levels of soil moisture. Large reservoirs on the major streams

provide municipal water and also serve as recreational

facilities. The surface water is generally of good quality and is

suitable for almost all uses.

The Carrizo-Wilcox and Trinity Group aquifer systems

provide water for municipal use, domestic use, livestock, and

some irrigation in this area. The eastern part of the area obtains

its ground water from the Carrizo-Wilcox aquifer system. The

water from this aquifer is moderately hard and contains a
268

median level of 369 parts per million (milligrams per liter) total

dissolved solids. Where this aquifer is pumped heavily for

irrigation, more saline water from adjacent aquifers may move

into it. Deep wells in the Carrizo-Wilcox aquifer can encounter

soft water where sodium is replacing calcium.

The western part of this area obtains its ground water from

sandstone and carbonate layers in the Trinity Group aquifer

system. This ground water is very hard and has a median level

of 619 parts per million (milligrams per liter) total dissolved

solids. About 30 percent of the samples from this aquifer

exceeded the national drinking water standards for nitrate.

Falling water tables limit the use of this aquifer.

Soils

The dominant soil orders in this MLRA are Alfisols,

Vertisols, and Ultisols. The soils are deep and have a medium

textured or moderately coarse textured surface layer and a

moderately permeable to very slowly permeable, clayey or

loamy subsoil. They have a thermic soil temperature regime, a

udic soil moisture regime, and mixed or smectitic mineralogy.

The soils are well drained to poorly drained and are nearly level

to gently sloping. The well drained and moderately well

drained soils are Paleudalfs (Annona and Freestone series),

Hapludults (Kirvin series), Hapludalfs (Woodtell, Karma, and

McKamie series), and Paleudults (Ruston series). Moderately

well drained Glossic Paleudalfs (Bernaldo, Whakana, and Vesey

series) and Aquic Glossudalfs (Raino series) formed on high

stream terraces and the erosional remnants of terraces. The

poorly drained soils are Glossaqualfs (Talco, Wrightsville, and

Derly series) and Epiaqualfs (Ivanhoe series). Very deep, well

drained soils with a thick sandy surface layer are Grossarenic

Paleudalfs (Pickton series) and Arenic Paleudalfs (Wolfpen

series). Very deep Entisols (Nahatche, Oklared, and Severn

series) formed on flood plains. Moderately well drained

Hapluderts (Kaufman and Billyhaw series) and somewhat

poorly drained Hapluderts (Gladewater and Texark series) also

formed on flood plains. Moderately well drained, very slowly

permeable Haplusterts (Burleson series) formed on clayey

terraces along the Trinity and Red Rivers.

Biological Resources

This area supports oak savanna vegetation. Hardwoods

consist of post oak, blackjack oak, hickory, and red oak. Native

pines occur in some areas. Pinehill bluestem is dominant on

most sites. Pinehill bluestem and beaked panicum are dominant

on poorly drained soils. Brownseed paspalum, purpletop,

longleaf uniola, Indiangrass, and beaked panicum grow

throughout the area. The area also supports a wide variety of

forbs, legumes, shrubs, and woody vines, such as spiderwort,

bundleflower, lespedeza, sensitivebrier, hackberry, hawthorn,

yaupon, elbowbush, greenbrier, and honeysuckle. This MLRA

is a transitional area between the cropland of MLRA 86A to the

west and the forested MLRA 133B to the east.

Some of the major wildlife species in this area are whitetailed deer, javelina, coyote, fox, bobcat, raccoon, skunk,

opossum, jackrabbit, cottontail, turkey, bobwhite quail, scaled

quail, white-winged dove, and mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 8%

Grassland—private, 54%

Forest—private, 26%; Federal, 1%

Urban development—private, 5%

Water—private, 4%

Other—private, 2%

Farmland makes up nearly all of this area. Most of the

farmland is used as pasture or woodland, and most of the

woodland is in pine plantations. In general, the soils in the area

have moderate to high suitability for woodland. Some of the

pasture was formerly cultivated cropland. About one-half of

present-day pasture supports improved grasses that are

fertilized. The cropland in the area is used primarily for corn,

peanuts, or hay. Truck crops are important in some areas. Urban

land is expanding in several areas.

The major soil resource concerns are water erosion,

maintenance of the content of organic matter and productivity

of the soils, and management of soil moisture. Conservation

practices on cropland generally include reduced till or no-till

systems, grassed waterways, buffer strips, crop residue

management, and nutrient management. Conservation practices

on pasture generally include grazing management systems,

applications of the proper amounts and kinds of fertilizer and

lime, and control of brush and weeds. The most important

conservation practices on woodland are control of runoff and

understory management. 
269

Figure K-1: Location of Land Resource Region K.

K—Northern Lake States Forest and

Forage Region

This region (shown in fig. K-1) is in Wisconsin (37 percent),

Minnesota (37 percent), Michigan (24 percent), and Illinois (2

percent). It makes up 118,775 square miles (307,795 square

kilometers).

This region is in the Central Lowland areas south and west of

the western Great Lakes. It is a glaciated region with numerous

lakes and wetlands. Slopes are nearly level to gently

undulating in areas of glacial lake deposits, gently undulating

to rolling on till plains and ground moraines, and steep on end

moraines, on valley sidewalls, and on escarpments along the

margins of lakes.

Winters are cold in this region, and significant amounts of

snow can accumulate. The average annual precipitation ranges

from 26 to 34 inches (660 to 865 millimeters). Most of the

precipitation falls in spring and summer. The average annual

temperature ranges from 39 to 44 degrees F (4 to 7 degrees C).

The freeze-free period ranges from 120 to 175 days, increasing

in length from north to south.

The total withdrawals of freshwater in this region average

about 5,650 million gallons per day (21,385 million liters per

day). About 82 percent is from surface water sources, and 18

percent is from ground water sources. Most of the region is used

for farming or timber production, but the region is heavily

populated from the center of the west shore of Lake Michigan

to its southern end. About 75 percent of the water in the region

is used for municipal and industrial supply, and 18 percent is

used for public supply. Wood pulp, paper, mining, and foodprocessing industries use significant amounts of the water.

The soils in this region are dominantly Histosols, Alfisols,

Spodosols, and Entisols. Some areas also have a significant

acreage of Mollisols or Inceptisols. Almost all of the soils in the

region have a frigid soil temperature regime, and all have an

aquic or udic soil moisture regime. Soils with a mesic soil

temperature regime are in many areas in the southern part of the

region. Mineralogy is dominantly mixed, but it is isotic in

some areas.

About 90 percent of the land in this region is privately

owned. Most of the Federal land is in national forests. The

native vegetation consists of forest species in about 58 percent

of the region (fig. K-2). The rest of the region is mainly
270 Major Land Resource Areas

cropland or grassland. Important crops include corn, wheat,

alfalfa, oats, barley, and soybeans. Much of the forage and feed

grain grown in the region is used by onsite dairy and beef cattle

industries. Other locally important crops include sunflowers,

potatoes, edible beans, sweet corn, peas, berries, and fruit. Water

erosion, especially on cropland, is a major resource concern.

Wind erosion is a hazard in areas of silty and sandy soils. Soil

wetness, fertility, and tilth and protection of water quality are

additional resource concerns. 

Figure K-2: A dominantly forested area of Land Resource Region K in Otter Tail County, Minnesota.
of the United States 271

Figure 57-1: Location of MLRA 57 in Land Resource Region K.

57—Northern Minnesota Gray Drift

This area is entirely in north-central Minnesota (fig. 57-1). It

makes up about 9,785 square miles (25,355 square kilometers).

The towns of Bagley, Bemidji, Blackduck, Detroit Lakes, Grand

Rapids, Mahnomen, Northhome, and Walker are in the northern

part of this MLRA, and Albany, Sauk Centre, and Browerville

are in the southern part. U.S. Highways 2, 10, 59, 71, and 169

cross the northern part, and Interstate 94 and U.S. Highway 71

cross the southern part. The northern part has a considerable

acreage of State forestland and numerous lakes, including

Leech Lake and Lake Winnibigoshish. It also includes parts of

the Chippewa National Forest, the southern part of the Red

Lake Indian Reservation, and most of the White Earth and

Leech Lake Indian Reservations. Some of the Camp Riley

Military Reservation is in the northeast corner of the southern

part of this MLRA.

Physiography

This area is in the Western Lake Section of the Central

Lowland Province of the Interior Plains. The landscape

developed through a series of glaciations and subsequent

retreating and wasting of the ice sheets. A complex pattern of

moraines, outwash plains, drumlins, lake plains, and drainages

characterizes the area. Lakes, ponds, and marshes are common.

Elevation is about 985 to 1,640 feet (300 to 500 meters). On

this choppy and complex landscape, relief typically is 15 to 50

feet (5 to 15 meters) within short distances.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Mississippi Headwaters (0701), 67 percent; Red (0902), 22

percent; Rainy (0903), 10 percent; and Western Lake Superior

(0401), 1 percent. This area is on a watershed divide in North

America. Surface water in most of the northern and western

parts of the area drains into the Red River of the North,

eventually entering Hudson Bay. The rest of the area is drained

by the Mississippi River, southward into the Gulf of Mexico.

The headwaters of the Mississippi River are in the northern part

of the area. The Mississippi River and its tributaries drain most

of the area.

Geology

All of this area is covered by Wisconsin-age drift. The

glacial deposits are from four major ice lobes—Des Moines,

Rainy, Superior, and Wadena. The thickness of the glacial till

ranges from 300 to 600 feet (90 to 185 meters). Some areas of

these deposits are overlain by outwash or lacustrine sediments.

Some depressional areas have an accumulation of organic

matter. These organic deposits are more than 8 feet (2.5 meters)

thick in some areas.

Climate

The average annual precipitation in this area is 23 to 29

inches (585 to 735 millimeters). About 65 percent of the annual

precipitation falls as rain during the 5-month growing season

(May through September), and about 18 percent falls as snow.

The average annual temperature is 37 to 43 degrees F (3 to 6

degrees C). The freeze-free period averages 150 days and ranges

from 120 to 175 days.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 7.0%; ground water, 4.5%

Livestock—surface water, 1.5%; ground water, 4.1%

Irrigation—surface water, 7.8%; ground water, 28.1%

Other—surface water, 46.9%; ground water, 0.0%

The total withdrawals average 64 million gallons per day

(240 million liters per day). About 37 percent is from ground

water sources, and 63 percent is from surface water sources. This

area has abundant supplies of both surface and ground water

that meet all of the current needs of the area. The surface water

generally is of good quality, and its use is not limited. Many

lakes provide ample opportunities for recreation.

Abundant supplies of good-quality ground water are in both

surficial and buried drift aquifers throughout this area. Water

from these aquifers is a calcium-magnesium-bicarbonate type

that is hard. The median concentrations of total dissolved
272 Major Land Resource Areas

solids are about 350 parts per million (milligrams per liter) in

the surficial drift aquifer and 450 in the buried drift aquifer.

Nitrate concentrations can approach the harmful limit of 10

parts per million (milligrams per liter) in the surficial drift

aquifer. Glacial till generally caps the buried drift aquifer,

which is thus more protected from contamination by surface

activities than the surficial drift aquifer. The deeper aquifer,

however, has very high levels of iron.

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, and Histosols. Some Mollisols are in the westernmost

part of the area. The soils in the area have a frigid soil

temperature regime, an aquic or udic soil moisture regime, and

mixed or smectitic mineralogy. They are very deep and

generally are sandy to loamy. Their natural drainage class is

related to landscape position. Endoaqualfs (Effie, Talmoon, and

Willosippi series) formed in till on moraines. Epiaqualfs

(Nokay, Paddock, and Watab series) and Glossudalfs (Blowers,

Sol, and Steamboat series) formed in till on drumlins and

moraines. Hapludalfs (Beltrami, Mahkonce, Naytahwaush,

Nebish, Snellman, Sugarbush, Suomi, Two Inlets, and Waukon

series) formed in till or outwash on moraines. Udipsamments

(Eagleview, Graycalm, and Nymore series) formed in outwash

on moraines. Haplosaprists (Cathro and Markey series) formed

in organic material over outwash or till on moraines.

Haplohemists (Rifle series) and Haplosaprists (Seelyeville

series) formed in a thick layer of organic material on moraines.

Biological Resources

Prior to settlement, the vegetation in this area was mainly a

mixture of deciduous trees and conifers. White pine and red

pine grew on moraines. Jack pine was dominant on outwash

plains and sandy lake plains. Red oak, sugar maple, and

basswood grew in sheltered areas close to lakes. Forested

lowlands were dominated by black spruce, tamarack, white

cedar, and black ash. Wetlands that were not forested were

dominated by sedge meadow communities. The western part of

the area was dominated by tall prairie grasses. Most of this area

is still forested. Aspen is the most common species both in pure

stands and in mixed stands with birch, maple, oak, white

spruce, and red pine.

Some of the major wildlife species in this area are whitetailed deer, black bear, ruffed grouse, and sharp-tailed grouse.

Because of its relatively unaltered landscape, this MLRA

supports a high percentage of the rare plants and animals that

occur in Minnesota. These species include the bald eagle and

the eastern timber wolf.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 16%

Grassland—private, 8%; Federal, 1%

Forest—private, 51%; Federal, 8%

Urban development—private, 3%

Water—private, 8%

Other—private, 5%

About 25 percent of this area is in farms. The farms generally

are small and are used mainly for forage and feed grain for

livestock. Livestock operations are in scattered areas

throughout the MLRA. Sunflowers, wheat, soybeans, and other

cash crops are grown on some farms, mainly in the western part

of the MLRA. Almost 60 percent of this area is forested. Part of

the forestland is in State and national forests. Hardwood forest

types make up most of the area. Aspen is the dominant species.

It is used in chipboard and pulp production. Softwood species

(fir, pine, and spruce) are used for pulp. This area has many

lakes, ponds, and marshes, and water-based recreation and

summer home development are significant economic

enterprises.

The major resource concerns are poor soil drainage, which

affects crop production; poor grazing management in areas of

forestland and grassland; water erosion and wind erosion; and

water quality. Conservation practices on cropland generally

include crop residue management and conservation crop

rotations, both of which help to control water erosion and wind

erosion. Drainage ditches are used to improve drainage. Filter

strips are installed along drainage ditches and streams to

preserve water quality. Prescribed grazing systems are used to

improve grazing management and remove livestock from

forested areas. Exclusion from use as needed, forest stand

improvement, riparian forest buffers, and proper establishment

of trees and shrubs restore damaged forests and improve water

quality. Field windbreaks reduce the hazard of wind erosion

and improve crop production. 

88—Northern Minnesota Glacial Lake

Basins

This area is entirely in Minnesota (fig. 88-1). It makes up

about 11,695 square miles (30,300 square kilometers). The

towns of Baudette, Big Falls, International Falls, Little Fork,

and Warroad are in the northern part of this MLRA. The towns

of Floodwood, Meadowlands, and McGregor are in the
of the United States 273

Figure 88-1: Location of MLRA 88 in Land Resource Region K.

basin is to the east to Lake Superior. The St. Louis, Whiteface,

Swan, and Savanna Rivers drain this basin. The drainage of the

glacial Lake Aitkin basin is to the south by way of the

Mississippi River. Numerous small lakes occur in this area.

Geology

The surface of this area is covered mostly by silty and clayey

lacustrine sediments and lake-modified glacial till. Crystalline

metamorphic rocks underlie the glacial deposits.

Climate

The average annual precipitation in this area is 20 to 29

inches (510 to 735 millimeters). About 68 percent of the annual

precipitation falls as rain during the 5-month growing season

(May through September), and about 20 percent falls as snow.

The average annual temperature is 36 to 41 degrees F (2 to 5

degrees C). The freeze-free period averages about 135 days and

ranges from 115 to 150 days.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 0.0%; ground water, 80.0%

Livestock—surface water, 6.7%; ground water, 13.3%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 0.0%; ground water, 0.0%

The total withdrawals average 1.5 million gallons per day

(5.5 million liters per day). About 93 percent is from ground

water sources, and 7 percent is from surface water sources. This

area has abundant supplies of both surface and ground water

that meet all of the current needs of the area. The surface water

generally is of good quality, and its use is not limited. Many

lakes provide ample opportunities for recreation.

Abundant supplies of good-quality ground water are in both

surficial and buried drift aquifers throughout this area. Water

from these aquifers is a calcium-magnesium-bicarbonate type

that is hard. The median concentrations of total dissolved

solids are about 350 parts per million (milligrams per liter) in

the surficial drift aquifer and 450 in the buried drift aquifer.

Nitrate concentrations can approach the harmful limit of 10

parts per million (milligrams per liter) in the surficial drift

aquifer. Glacial till generally caps the buried drift aquifer,

which is thus more protected from contamination by surface

activities than the surficial drift aquifer. The deeper aquifer,

however, has very high levels of iron.

Ground water for domestic use is obtained from the

Proterozoic Metasedimentary aquifer in the southeastern part of

this MLRA. This aquifer consists of argillite, slate, and

metagraywacke and has calcium-magnesium-bicarbonate type

southern part. Small parts of the Superior and Chippewa

National Forests are in this area, but most of the area is in State

forests. This MLRA includes the Big Bog and Nett Lake Indian

Reservations, part of the Leech Lake Indian Reservation, and

most of the Red Lake Indian Reservation.

Physiography

Most of this area is in the Western Lake Section of the

Central Lowland Province of the Interior Plains. The eastern

one-eighth of the area is in the Superior Upland Province of the

Laurentian Upland. This MLRA is in the glacial lakebeds of

Agassiz, Upham, and Aitkin. These glacial lake plains have

remnants of gravelly beaches, strandlines, deltas, and sandbars.

The mostly level or nearly level plains are bordered by some

gently sloping strandlines and rolling dune land. Elevation is

1,350 feet (410 meters), decreasing gradually to 900 feet (275)

meters) in the north. Ditches have been used in an attempt to

drain the many wet areas in the MLRA, but low gradients

commonly prevent adequate removal of surface and subsurface

water for cropping.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Rainy (0903), 48 percent; Red (0902), 24 percent; Western

Lake Superior (0401), 14 percent; and Mississippi Headwaters

(0701), 14 percent. Most of this area was inundated by glacial

Lake Agassiz. The general slope and drainage are toward the

north into the Rainy River and eventually into Hudson Bay.

The Clearwater, Moose, Red Lake, and Roseau Rivers drain the

southwestern part of the area and eventually flow into the Red

River. The divide between the Rainy and Red River drainage

basins lies in this area. The drainage of the glacial Lake Upham
274 Major Land Resource Areas

water that is hard. The water has a median level of total

dissolved solids of about 250 parts per million (milligrams per

liter). This aquifer has the best quality water of all the

crystalline rock aquifers in Minnesota.

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, and Histosols. The soils in the area have a frigid soil

temperature regime, an aquic or udic soil moisture regime, and

mixed, smectitic, or isotic mineralogy. They are very deep, are

sandy to clayey, and are dominantly somewhat poorly drained

to very poorly drained. Extensive areas of organic soils occur in

the MLRA. Most of the organic soils in the Agassiz Basin are

slightly lower on the landscape than the surrounding

mineral soils, whereas the large areas of organic soils in the

Upham and Aitkin Basins typically are slightly domed and are

slightly higher on the landscape than the surrounding mineral

soils.

Aqualfs (Chilgren, Indus, and Spooner series) formed in

glaciolacustrine sediments or water-worked till. Udalfs

(Baudette, Kooch, and Taylor series) formed in water-modified

till or glaciolacustrine sediments. Psamments (Clearriver,

Cormant, Graycalm, Hiwood, Menahga, Redby, Two Inlets, and

Zimmerman series) formed in glaciolacustrine sediments on

lake plains. Haplosaprists (Cathro, Berner, Dora, and Markey

series) formed in organic material over glaciolacustrine

sediments or water-modified till. Haplohemists (Greenwood and

Rifle series), Haplosaprists (Seelyeville series), and

Sphagnofibrists (Lobo series) formed in a thick layer of organic

material on lake plains.

Biological Resources

Prior to settlement, the vegetation in this area was a mixture

of deciduous trees and conifers. White pine and red pine grew

on moraines. Jack pine was dominant on outwash plains and

sandy lake plains. Red oak, sugar maple, and basswood grew in

sheltered areas close to lakes. Forested lowlands were

dominated by black spruce, tamarack, white cedar, and black

ash. Wetlands that were not forested were dominated by sedge

meadow communities. Much of this area remains forested, but

small areas of prairie occur in the western part of the area. Aspen

is the most common tree species both in pure stands and in

mixed stands with birch, maple, oak, white spruce, and red pine.

Some of the major wildlife species in this area are whitetailed deer, black bear, ruffed grouse, and sharp-tailed grouse.

Because of its relatively unaltered landscape, this area supports

a high percentage of the rare plants and animals that occur in

Minnesota. These species include the bald eagle and the

eastern timber wolf.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 7%

Grassland—private, 2%; Federal, 1%

Forest—private, 73%; Federal, 2%

Urban development—private, 1%

Water—private, 11%

Other—private, 3%

About 75 percent of this area is forested, dominantly by the

aspen cover type. Hardwood and softwood species are

harvested mostly for pulp. Most of the cropland in this MLRA

is in the western part of the area. The main crops are alfalfa,

barley, oats, sunflowers, and wheat. A short growing season,

excessive periods of rainfall, and poor drainage can reduce

yields in some years. Specialty crops, including bluegrass seed,

foundation seed potatoes, and wild rice, are grown in some

areas. Scattered livestock operations are throughout the area.

Two large, frequently used lakes are in this MLRA. These are

Leech Lake and Cass Lake. Water-based recreation and summer

home development are significant economic enterprises.

The major resource concerns are excessive soil wetness, the

short growing season, and surface compaction. Some sandy

areas are subject to wind erosion. The important conservation

practices on cropland include selection of crops that are tolerant

of wetness and a short growing season. They also include

timely tillage, which improves yields. Cover crops and

minimum tillage can help to overcome the effects of strong

winds on sandy soils. Timely harvesting of trees can minimize

compaction when the soils are wet and can enhance the

regeneration of tree species. 

89—Wisconsin Central Sands

This area is entirely in Wisconsin (fig. 89-1). It makes up

about 3,420 square miles (8,860 square kilometers). The cities

of Black River Falls, Friendship, Mauston, New Lisbon, Stevens

Point, Tomah, Wisconsin Dells, and Wisconsin Rapids are in the

area. Interstates 90 and 94 join in the western part of the area,

and U.S. Highway 51 crosses the northeastern part. The north

end of the Fort McCoy Military Reservation is in the southwest

part of the area. The Meadow Valley Wildlife Area and the

Necedah Wildlife Refuge are completely within this MLRA.

The Ho-Chunk Nation (formerly the Wisconsin Winnebago

Tribe) does not have a defined reservation, but the Nation’s

center of government is in Jackson County and the majority of

Ho-Chunk tribal lands are within this MLRA.
of the United States 275

Figure 89-1: Location of MLRA 89 in Land Resource Region K.

and also has outwash and glacial lacustrine sand from the more

recent Wisconsin Glaciation. Glacial Lake Wisconsin covered

more than 1,825 square miles (4,730 square kilometers), most of

which was in this MLRA.

Climate

The average annual precipitation in this area is 30 to 33

inches (760 to 840 millimeters). Most of the rainfall occurs as

convective thunderstorms during the growing season. The

annual snowfall ranges from about 35 to 50 inches (90 to 125

centimeters). It generally occurs from October through April.

The average annual temperature is 42 to 45 degrees F (6 to 7

degrees C). The freeze-free period averages about 150 days and

ranges from 135 to 165 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 10.4%; ground water, 12.5%

Livestock—surface water, 0.8%; ground water, 4.1%

Irrigation—surface water, 0.7%; ground water, 69.5%

Other—surface water, 2.1%; ground water, 0.0%

The total withdrawals average 145 million gallons per day

(550 million liters per day). About 86 percent is from ground

water sources, and 14 percent is from surface water sources.

The supply of surface and ground water is abundant, but in

years of normal precipitation, the moderate precipitation is

inadequate for crops and pasture on sandy soils. In years of

little or no precipitation, crop yields are seriously reduced.

Irrigation is widely used for high-value crops. Drainage of the

soils on wet lowlands is needed for good crop production. The

surface water is in streams, rivers, and flowages. It is used

mainly for power generation, irrigation, recreation, habitat for

fish and wildlife, and disposal of effluent from sewage

treatment plants.

Ground water is the major supply used to meet most

domestic, agricultural, municipal, and industrial needs in this

area. The water comes from aquifers in unconsolidated sand and

gravel deposits overlying Cambrian sandstone or from the

sandstone itself. Probable yields from wells in sand and gravel

aquifers range from 100 to more than 1,000 gallons per minute

(380 to more than 3,785 liters per minute). Wells in glacial till

on moraines yield 50 to 1,000 gallons per minute (190 to 3,785

liters per minute). Wells in the sandstone bedrock typically

yield 100 to 800 gallons per minute (380 to 3,030 liters per

minute). The water is a calcium-magnesium-bicarbonate type

that is moderately hard or hard and ranges from 80 to 220 parts

per million (milligrams per liter) calcium carbonate. It is of

good quality, containing less than 300 parts per million

(milligrams per liter) total dissolved solids. The sand and gravel

deposits lie over Precambrian crystalline rocks in the northern

Physiography

This area is in the Wisconsin Driftless Section of the

Central Lowland Province of the Interior Plains. It is an area

of isolated buttes and mesas, valley trains, flood plains, and

extensive wetlands. The southern and eastern parts of the area

are on a large glacial lake and outwash plain, and the northern

and western parts are mostly on low hills and pediments.

Elevation is 880 feet (270 meters) in the southern part of the

area, at the village of Lyndon Station, with a gradual slope to

about 1,110 feet (340 meters) in the northeastern part of the

area, at the city of Stevens Point. The maximum elevation is

about 1,400 feet (425 meters). It is on Saddle Mound, in

Jackson County. The maximum local relief is about 400 feet

(120 meters), but relief is considerably lower in most of the

area.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Wisconsin (0707), 70 percent; Upper Mississippi-Black-Root

(0704), 24 percent; and Chippewa (0705), 6 percent. The

Chippewa, Black, and Wisconsin Rivers, major tributaries of the

Mississippi River, drain this area.

Geology

This area is underlain dominantly by weak Cambrian

sandstone and interbedded sandstone and shale formations

locally named Wonewoc, Eau Claire, and Mount Simon. Some

areas are underlain by Precambrian metamorphic and igneous

rocks. Some were most likely glaciated between 25,000 and

about 2,400,000 years ago, and others probably were not

glaciated. Although this part of Wisconsin is often referred to as

the “Driftless Area,” it still has remnants of very old glacial drift
276 Major Land Resource Areas

part of this area. The water from these deposits has less total

dissolved solids and is less hard than the water that lies over

sandstone in the southern part of the area. Minor water use

problems are caused by hardness and locally by high

concentrations of iron produced by reducing conditions in

marshes and swamps. The regional flow of ground water is

towards the Wisconsin River.

Soils

The soil orders in this MLRA are dominantly Entisols,

Alfisols, Histosols, and Spodosols. Mollisols occur to a much

lesser extent. The soil temperature regime is dominantly mesic,

but it is frigid in the soils in low-lying depressions that are wet

for long periods and in areas on the northern fringe of the

MLRA. The soils in this MLRA have a udic or aquic soil

moisture regime and dominantly have mixed or siliceous

mineralogy. They generally are moderately deep to very deep,

well drained to very poorly drained, and sandy to clayey. In

much of the area, loess occurs in thin layers or does not occur at

all. On some flood plains, however, silty alluvium is derived

from the thicker mantles of loess on soils in the adjacent

MLRAs.

Hills and pediments, which are generally in the northern and

western parts of this MLRA, have Haplorthods (Ludington and

Humbird series) and Epiaquods (Fairchild and Merrillan series),

which formed dominantly in sandy and loamy residuum derived

from interbedded sandstone and shale, and Quartzipsamments,

which formed in sandy slope alluvium and sandy residuum

(Boone series) and in sandy pedisediment (Tarr series). The

glacial lakes, outwash plains, and valley trains in the eastern

and southern parts of the area have Udipsamments (Plainfield

series), Psammaquents (Newlang series), Hapludalfs (Wyeville

series), and Haplosaprists (Dawsil series), all of which formed

dominantly in outwash sand; lacustrine sand, silt, and clay; and

organic material. The flood plains throughout the area are

dominated by Udipsamments (Algansee and Scotah series) and

Fluvaquents (Kalmarville series).

Biological Resources

This area is in the southern part of the conifer-hardwood

forest, which includes xeric pine savannas and oak barrens.

Jack pine, northern pin oak, black oak, and white oak are the

dominant trees. The extensive wetlands in the area support red

maple, aspen, paper birch, and speckled alder.

Some of the major wildlife species in this area are whitetailed deer, ruffed grouse, wild turkey, fox and gray squirrels,

cottontail rabbits, ducks, and geese. Red fox, gray fox, coyote,

muskrat, raccoon, and beaver are the main furbearers. Small

populations of prairie chickens inhabit the area. Fishing is

limited mostly to constructed impoundments and rivers. Local

fish species include rainbow trout, brook trout, walleye pike,

largemouth bass, smallmouth bass, bluegill, yellow perch, and

northern pike. Colburn, Sandhill, Wood County, and Meadow

Valley State Wildlife Areas, along with Buena Vista Marsh,

Black River State Forest, and the Necedah National Wildlife

Refuge, provide wildlife habitat throughout the area.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 20%

Grassland—private, 6%

Forest—private, 53%; Federal, 5%

Urban development—private, 6%

Water—private, 4%

Other—private, 6%

Most of this area is forestland. Lumber and pulp production

is an active industry. The rest of the area is used mainly for

cash-grain crops, dairy farms, livestock grazing, irrigated

vegetables, Christmas trees, or cranberries. Most of the irrigated

areas are used for potatoes, snap beans, peas, or sweet corn.

Tourism, recreation, and wildlife management are important in

this MLRA. Dams in two areas on the Wisconsin River have

formed the Petenwell Flowage and Castle Rock Lake. Because

of the abundance of water, the thousands of acres of State and

county forests, and many large public hunting grounds,

hunting and fishing are popular activities.

The major soil resource management concern is wind

erosion. Maintenance of the content of organic matter and

productivity of the soils and soil moisture management are

additional concerns. The important conservation practices on

cropland include systems of crop residue management

(especially no-till systems that eliminate the need for summer

fallow tillage), cover crops, windbreaks, vegetative wind

barriers, wind stripcropping, and nutrient management. 

90A—Wisconsin and Minnesota Thin

Loess and Till, Northern Part

This area (shown in fig. 90A-1) is in Wisconsin (69 percent),

Minnesota (26 percent), and Michigan (5 percent). It makes up

about 17,535 square miles (45,440 square kilometers). It

includes the cities and towns of Frederic, Ladysmith, Park Falls,

Crandon, and Wittenberg, Wisconsin; Cloquet, Hinckley, and

Milaca, Minnesota; and Iron River, Michigan. Interstate 35

crosses the part of this MLRA in Minnesota, and U.S. Highway

8 crosses much of the area from east to west. Parts of the

Chequamegon, Nicolet, and Ottawa National Forests and

numerous State parks are in this area. Parts or all of the St. Croix

Chippewa Communities, Lac Court Oreilles, Lac Du Flambeau,

Menominee, Potawatomi, Stockbridge, and Mole Lake Indian

Reservations are in the area.
of the United States 277

Figure 90A-1: Location of MLRA 90A in Land Resource Region K.

Geology

Precambrian-age bedrock underlies most of the glacial

deposits in this MLRA. The bedrock is a complex of folded and

faulted igneous and metamorphic rocks. The bedrock terrain

has been modified by glaciation and is covered in most areas

by Pleistocene deposits and windblown silts. The glacial

deposits form an almost continuous cover in most areas. The

drift is as much as several hundred feet thick in many areas.

Loess covered the area shortly after the glacial ice melted.

Climate

The average annual precipitation in this area is 26 to 34

inches (660 to 865 millimeters). The precipitation is fairly well

distributed throughout the year but reaches a slight peak in

spring. Rainfall commonly occurs as convective thunderstorms

during the growing season. Snowfall generally occurs from

October through April. The average annual temperature is 38 to

45 degrees F (3 to 7 degrees C). The freeze-free period averages

about 145 days and ranges from 110 to 180 days.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 14.5%; ground water, 8.3%

Livestock—surface water, 2.1%; ground water, 3.1%

Irrigation—surface water, 1.5%; ground water, 6.9%

Other—surface water, 63.2%; ground water, 0.5%

The total withdrawals average 205 million gallons per day

(775 million liters per day). About 19 percent is from ground

water sources, and 81 percent is from surface water sources. The

moderate precipitation generally is adequate for crops and

pasture, but in years of little or no precipitation, crops on sandy

soils are damaged by a shortage of moisture. Drainage of most

of the soils on wet lowlands is needed for good crop and forage

production. Surface water and ground water are abundant and

readily available. The sources of surface water are the many

lakes and streams. This water is used mostly for recreational

activities, partly for watering livestock, and occasionally for

irrigation. Water quality is generally good. Landlocked lakes

and lakes and streams that border bogs and swamps are more

acid than the other surface water in the area. Spring-fed lakes

have the highest pH value. The water is very soft in most of the

lakes, but hard water occurs in the spring-fed lakes and in

streams.

Ground water is abundant in deep glacial deposits in most of

this area. It also occurs in sedimentary and volcanic rocks in the

western part of the area. It is scarce in areas where the layer of

drift is thin. The water meets the domestic, agricultural,

municipal, industrial, rural, and irrigation needs in the area. The

content of dissolved solids in the ground water from all the

Physiography

The part of this area in Minnesota is mostly in the Western

Lake Section of the Central Lowland Province of the Interior

Plains. Nearly all of the parts in Wisconsin and Michigan are in

the Superior Upland Province of the Laurentian Upland. Three

distinct lobes of the Laurentian Ice Sheet (Superior, Chippewa,

and Green Bay) played major roles in shaping the landscape in

this area. The landscape is characterized by gently undulating

to rolling, loess-mantled till plains, drumlin fields, and end

moraines mixed with outwash plains associated with major

glacial drainageways, swamps, and bogs. In some areas lake

plains and ice-walled lakes are significant. Steeper areas occur

mostly as valley side slopes along flood plains and as

escarpments along the margins of lakes. Lakes are common, and

streams generally have a dendritic pattern. Elevation ranges

from 1,100 to 1,950 feet (335 to 595 meters). Local relief is

mainly less than 10 feet to 20 feet (3 to 6 meters), but some

major valleys and hills are 200 feet (60 meters) above the

adjacent lowland.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Chippewa (0705), 29 percent; St. Croix (0703), 24 percent;

Northwestern Lake Michigan (0403), 23 percent; Mississippi

Headwaters (0701), 13 percent; Wisconsin (0707), 8 percent;

and Western Lake Superior (0401), 3 percent. The major rivers

crossing this area are the Chippewa, St. Croix, Mississippi, and

Wisconsin Rivers. The St. Croix and Wolf Rivers in Wisconsin

have been designated National Scenic Rivers. The Pine and

Popple Rivers in Wisconsin and the Rum and Kettle Rivers in

Minnesota have been designated as National Wild and Scenic

Rivers. Lakes, ponds, and marshes are common throughout the

area.
278 Major Land Resource Areas

various aquifers in this area is low, typically about 200 parts per

million (milligrams per liter), and the water generally is

moderately hard or hard. The level of total dissolved solids in

some of the water can be much higher because of a high content

of limestone in some of the glacial deposits. Most of this area

obtains ground water from unconsolidated glacial sand and

gravel deposits on or very near the surface. Some wells tap the

Cambrian sandstone in the southwestern part of the area, in

Wisconsin.

In northwest Wisconsin (Ashland and Bayfield Counties),

where the glacial deposits do not occur, and in much of the part

of this area in Minnesota, ground water from sedimentary and

volcanic rock aquifers is used. This water is of very good

quality, but many soils have very porous layers that are poor

filters of domestic waste and agricultural chemicals, so there is

a risk of contamination from development and agriculture.

Minor problems may be caused by hardness and in some areas

by high concentrations of iron. About 65 percent of the wells in

the part of this area in Michigan had water with more than

1,500 parts per billion (micrograms per liter) iron. Yields of

water from the glacial deposits vary. Glacial drift consisting

mainly of sand and gravel yields 100 to more than 1,000

gallons per minute (380 to more than 3,785 liters per minute).

Glacial till yields generally less than 100 gallons per minute

(380 liters per minute).

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, Histosols, and Spodosols. The soils in the area have a

frigid soil temperature regime, a udic or aquic soil moisture

regime, and mixed mineralogy.

Glossudalfs (Amery, Brennyville, Freeon, Frogcreek,

Glendenning, Haugen, Magnor, Milaca, Mora, Stinnett, and

Santiago series) formed in a thin, discontinuous silty mantle

over firm or friable till. Glossudalfs formed in outwash mantled

with silty material (Antigo, Sconsin, Billyboy, and Ossmer

series) or in outwash mantled with loamy material (Rosholt,

Scoba, Scott Lake, Chetek, and Oesterle series). Udipsamments

(Grayling, Mahtomedi, and Friendship series) formed in sandy

outwash on outwash plains and stream terraces. Haplorthods

formed in sandy loam or loamy sand till mantled with silty

material (Beaverbay, Chequamegon, Mudlake, Wabeno, and

Soperton series) or entirely in till (Newot, Newood, Pesabic,

Kennan, Sarona, Sarwet, Keweenaw, Parkfalls, and Stanberry

series). Haplorthods are on outwash plains. They formed in

outwash mantled with silty material (Stambaugh, Vanzile, and

Spiderlake series), in outwash mantled with loamy material

(Padus, Pence, Tipler, and Manitowish series), or in sandy

outwash (Vilas, Lindquist, Croswell, and Chinwhisker series).

Glossaqualfs (Cebana series) formed in till mantled with silty

material. They are in swales. Epiaqualfs (Capitola and Wozny

series) formed in sandy loam or loamy sand till in depressions

on moraines. Haplosaprists (Lupton, Cathro, Loxley, and

Beseman series) formed in organic deposits in basins and

depressions. Fluvaquents (Fordum series) formed in loamy

alluvium on flood plains.

Biological Resources

This area is in a conifer-hardwood forest. Sugar maple,

basswood, yellow birch, white ash, red oak, white oak, aspen,

eastern hemlock, red pine, and white pine are the dominant

trees. Poorly drained soils support black ash, green ash, silver

maple, red maple, swamp white oak, black spruce, tamarack,

and speckled alder.

Some of the major wildlife species in this area are whitetailed deer, black bear, eastern gray wolf, ruffed grouse, sharptailed grouse, woodcock, fox squirrel, gray squirrel, snowshoe

hare, ducks, and geese. Red fox, bobcat, coyote, muskrat, fisher,

mink, otter, raccoon, and beaver are the main furbearers. A small

herd of elk was released in this area, and the number of elk is

increasing. State wildlife areas and substantial national and

county forests provide good wildlife habitat. Fishing occurs in

constructed impoundments, flowages, lakes, and rivers. The

species of fish in the area include rainbow trout, brook trout,

walleye pike, largemouth bass, smallmouth bass, bluegill, black

crappie, yellow perch, musky, and northern pike.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 10%

Grassland—private, 7%; Federal, 3%

Forest—private, 58%; Federal, 7%

Urban development—private, 3%

Water—private, 5%; Federal, 2%

Other—private, 5%

This area has a significant acreage of public and private

forestland used to support the paper and lumber industry. Sap

collection from sugar maple and syrup production are important

forestry enterprises. Agricultural enterprises include row crops,

dairy farms, and beef operations. Crops include corn, soybeans,

oats, wheat, and alfalfa. Tourism, recreation, and wildlife

management are important. Because of the abundance of water,

the many acres of national and county forests, and public

hunting grounds, hunting, fishing, snowmobiling, hiking, and

skiing are popular activities.

The major soil resource management concerns are water

erosion, wetness, soil fertility, and soil tilth. Conservation

practices on cropland generally include crop rotations,

conservation tillage systems (especially no-till systems),

contour farming, contour stripcropping, and grassed waterways.

A combination of surface and subsurface drainage systems is

needed in most areas of poorly drained soils. 
of the United States 279

Figure 90B-1: Location of MLRA 90B in Land Resource Region K.

90B—Wisconsin and Minnesota Thin

Loess and Till, Southern Part

This area (shown in fig. 90B-1) is in Wisconsin (79 percent)

and Minnesota (21 percent). It makes up about 8,935 square

miles (23,155 square kilometers). The cities of River Falls,

Marshfield, Wausau, Rice Lake, and St. Croix Falls, Wisconsin,

and North St. Paul, Forest Lake, White Bear Lake, Stillwater,

and Foley, Minnesota, are in this MLRA. Interstates 35, 94, and

694 cross parts of the MLRA. The area has no Federal land and

has only a few State parks. It has numerous State wildlife areas,

including the Paul J. Olson, George W. Mead, Dewey Marsh,

Sportsman Lake, Ackley, and McMillan Marsh State Wildlife

Areas.

Physiography

The smaller, separate part of this area in Minnesota is in the

Western Lake Section of the Central Lowland Province of the

Interior Plains. Most of the larger part of the area is in the

Wisconsin Driftless Section of the same province and division.

The northern edges of the part of the MLRA in Wisconsin are in

the Superior Upland Province of the Laurentian Upland. This

MLRA is characterized by ground moraines, outwash plains,

valley trains, glacial lakes, and sandstone hills. Much of the

area is gently undulating to rolling. The steepest areas are

adjacent to river valleys. Natural lakes, bogs, swamps, flood

plains, and depressions are fairly extensive. Elevation ranges

from about 675 feet (205 meters) at the St. Croix River near

Prescott, Wisconsin, to about 1,550 feet (470 meters) just north

of Medford, Wisconsin. Local relief is commonly 10 to 20 feet

(3 to 6 meters) but can be more than 300 feet (90 meters) along

the St. Croix River.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Chippewa (0705), 34 percent; Wisconsin (0707), 28 percent; St.

Croix (0703), 15 percent; Mississippi Headwaters (0701), 12

percent; and Upper Mississippi-Black-Root (0704), 11 percent.

The Mississippi River and some of its major tributaries,

including the Chippewa, Black, Wisconsin, and St. Croix

Rivers, drain this MLRA. The Rum River is a National Wild

and Scenic River that crosses the small, separate part of the area

in Minnesota. The reaches of the St. Croix and Lower St. Croix

Rivers, on the border between Minnesota and Wisconsin, are

National Scenic Rivers.

Geology

This MLRA was most recently glaciated during a period that

straddled the Early Wisconsin Ice Age (early St. Croix and early

Chippewa phases) and other earlier glaciations (Baldwin,

Dallas, Hamburg, and Nasonville phases). The glacial drift in

this area was probably deposited 790,000 to 16,000 years ago

and is dominantly from a Superior basin origin with no

carbonates. It may, however, be underlain by older glacial drift

that is from a western source and contains carbonates. This

older drift was deposited 790,000 to 2,500,000 years ago.

Outwash is generally confined to those river valleys that

previously carried glacial meltwater. Ice-walled lakes and other

glacial lakes are common in this MLRA, and they have

distinctive landforms with smooth slopes and silty and clayey

soils. The sandstone hills are dominantly weak Cambrian

sandstones locally named the Tunnel City, Wonewoc, Eau

Claire, and Mount Simon Formations. A mantle of loess is in

most areas of the MLRA. It ranges from a few inches (50

millimeters) to more than 6.5 feet (2 meters) in thickness.

Climate

The average annual precipitation in this area is 27 to 33

inches (685 to 840 millimeters). Most of the rainfall occurs as

convective thunderstorms during the growing season. The

annual snowfall ranges from about 35 to 50 inches (90 to 125

centimeters). It generally occurs from October through April.

The average annual temperature is 40 to 46 degrees F (4 to 8

degrees C). The freeze-free period averages about 160 days and

ranges from 135 to 180 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 5.4%; ground water, 5.3%

Livestock—surface water, 0.2%; ground water, 0.3%

Irrigation—surface water, 0.2%; ground water, 1.5%

Other—surface water, 81.1%; ground water, 6.0%
280 Major Land Resource Areas

The total withdrawals average 1,140 million gallons per day

(4,315 million liters per day). About 13 percent is from ground

water sources, and 87 percent is from surface water sources.

Both surface water and ground water are abundant. Surface

water occurs as ponds, lakes, streams, rivers, and flowages. It

generally is of good quality, but it is mainly hard or very hard.

It is used mainly for public supply, industry, power generation,

recreation, fish habitat, sewage disposal, and livestock watering.

Ground water is used to meet some of the domestic,

irrigation, and municipal needs in this MLRA. Most of the

ground water in the eastern part of the area comes from

unconsolidated sand and gravel aquifers in glacial deposits. In

western Wisconsin and eastern Minnesota, the ground water

also is obtained from Cambrian sandstone and dolomite

aquifers. Precambrian crystalline rock provides some ground

water for domestic use and livestock in the far western part of

this area. The Prairie du Chien-Jordan aquifer in the part of this

area in southeastern Minnesota is one of the most heavily used

aquifers in the State. The ground water from all of the aquifers

generally is moderately hard or hard. Water in the Cambrian

sandstone in western Wisconsin may have some high

concentrations of iron, manganese, and sulfides that limit its

use. All of the aquifers typically have water with less than 500

parts per million (milligrams per liter) total dissolved solids.

Nitrates have been detected in a majority of the wells.

Wells in the Cambrian formation yield less than 100 gallons

per minute (380 liters per minute). The sand and gravel aquifer

and the Prairie du Chien-Jordan aquifer yield 100 to more than

1,000 gallons per minute (380 to more than 3,785 liters per

minute). Glacial till yields are generally less than 100 gallons

per minute (380 liters per minute). The Precambrian formation

is not dependable and yields generally less than 20 gallons per

minute (75 liters per minute). The flow of the ground water

generally is towards the local streams and rivers. The regional

flow at depth is toward the Wisconsin and Chippewa Rivers.

Soils

The soil orders in this MLRA are dominantly Entisols,

Alfisols, Histosols, Spodosols, and Inceptisols. Mollisols occur

to a much lesser extent. The soil temperature regime is

dominantly frigid but is mesic in a few soils along the St. Croix

River. The soils in the area have a udic or aquic soil moisture

regime. Mineralogy is dominantly mixed but is siliceous in a

few areas. The soils generally are moderately deep to very deep,

well drained to very poorly drained, and sandy to loamy. Thin

to thick layers of loess are throughout the area. The thicker

layers generally are closer to the St. Croix River. Alluvium is

sandy to silty.

Most of the soils on ground moraines are Glossudalfs

(Almena, Alstad, Branstad, Freeon, Loyal, Magnor, Spencer,

and Withee series). Most of the soils that are in glacial lakebeds

and formed mostly in silty and clayey sediments are

Glossudalfs (Comstock, Crystal Lake, Grasston, and

Longsiding series) and Hapludalfs (Dalbo series). The soils on

outwash plains and valley trains commonly are Glossudalfs or

Hapludalfs (Anigon, Brill, Antigo, Langlade, Brander,

Blackriver, Ribriver, Rosholt, and Chetek series) that formed in

silty or loamy alluvium over outwash or Udipsamments

(Menahga and Mahtomedi series) that formed entirely in

outwash. The major soils on sandstone hills are Glossudalfs

(Dobie series) that formed in a thin loess mantle over loamy

residuum, Hapludalfs (Hayriver series) that formed in loamy

slope alluvium and loamy residuum, and Psamments

(Twinmound series) that formed in sandy slope alluvium and

sandy residuum. Typic Haplosaprists (Seelyeville series) and

Terric Haplosaprists (Markey series) formed mostly in organic

material underlain by outwash, till, alluvium, or lacustrine

sediments. They are in bogs and swamps. The soils on flood

plains throughout the area are Dystrudepts (Moppet series) and

Fluvaquents (Fordum series) that formed in loamy and sandy

alluvium. The soils on flood plains that drain loess-mantled

areas are Endoaquolls (Vancecreek series) that formed

dominantly in silty alluvium.

Biological Resources

This area is in the southern part of the conifer-hardwood

forest. Oak savanna, prairie, and lowland swamps also occur in

the area. Sugar maple, basswood, yellow birch, white ash, red

oak, white oak, aspen, eastern hemlock, red pine, and white

pine are the dominant trees. Swampy areas support black ash,

green ash, silver maple, red maple, swamp white oak, black

spruce, tamarack, and speckled alder.

Some of the major wildlife species in this area are whitetailed deer, black bear, ruffed grouse, wild turkey, woodcock,

fox squirrel, gray squirrel, cottontail rabbits, ducks, and geese.

Red fox, bobcat, coyote, muskrat, mink, otter, raccoon, and

beaver are the main furbearers. Grassy lowlands and old

pastures provide scattered habitat for prairie chickens and gray

partridge. The numerous State wildlife areas and the substantial

acreage of county forestland provide good wildlife habitat and

opportunities for recreational hunting. Fishing occurs in

constructed impoundments, flowages, and rivers. The species of

fish in the area include rainbow trout, brook trout, walleye pike,

largemouth bass, smallmouth bass, bluegill, yellow perch, and

northern pike.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 43%

Grassland—private, 14%

Forest—private, 28%

Urban development—private, 8%

Water—private, 2%

Other—private, 5%
of the United States 281

Cropland and forestland are the major land uses in this area.

Lumber and pulp production is an active industry. Agricultural

enterprises include row crops, dairy farms, and livestock

operations. The major crops are corn, soybeans, oats, barley,

and alfalfa. A small acreage is used for specialty crops,

including sweet corn, potatoes, peas, snap beans, strawberries,

apples, and ginseng. Tourism, recreation, and wildlife

management are important. Damming of the Wisconsin River

has formed Lake Dubay. Because of the abundance of water and

the many acres of county forest and public hunting grounds,

hunting and fishing are popular activities.

The major soil resource management concerns are water

erosion, excessive soil wetness, soil fertility, and soil tilth.

Conservation practices on cropland generally include crop

rotations, conservation tillage systems (especially no-till

systems), contour farming, contour stripcropping, and grassed

waterways. A combination of surface and subsurface drainage

systems is needed in most areas of poorly drained soils. 

Figure 91A-1: Location of MLRA 91A in Land Resource Region K.

91A—Central Minnesota Sandy Outwash

This area is entirely in Minnesota (fig. 91A-1). It makes up

about 4,600 square miles (11,920 kilometers). The cities and

towns in this MLRA include Park Rapids, Perham, Wadena,

Brainerd, Little Falls, St. Cloud, Monticello, and Rosemount.

Interstate 94 and U.S. Highway 10 cross parts of the MLRA.

The Camp Riley Military Reservation is in the central part of

the area. A small part of the White Earth Indian Reservation is

in the northwest corner of the area. This MLRA has numerous

State parks and State forests.

Physiography

This area is in the Western Lake Section of the Central

Lowland Province of the Interior Plains. The area consists

mostly of large outwash plains and stream terraces. The

outwash was deposited by Wisconsin-age glaciers. Most of the

area is gently undulating to rolling. Some steep areas are on

valley sidewalls or on escarpments along lake margins.

Elevation ranges from 820 to 1,470 feet (250 to 450 meters).

Local relief is mostly 10 to 20 feet (3 to 6 meters), but it as

much as 80 feet (25 meters) in some areas.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Mississippi Headwaters (0701), 73 percent; Red (0902), 20

percent; Upper Mississippi-Black-Root (0704), 4 percent; and

Minnesota (0702), 3 percent. The Mississippi River and its

many tributaries drain much of this area. Lakes, ponds, and

marshes are common throughout the area.

Geology

Most of this MLRA consists of coarse textured outwash with

a thin, discontinuous mantle of loamy material. The thickness

of the outwash ranges from 3 feet (1 meter) to more than 100

feet (30 meters). Loamy glacial till typically underlies the

outwash. Organic material is in many of the larger basins and

depressions. Recent loamy alluvium is on flood plains. In a few

areas glacial till is along steep valley sidewalls. The western

part of the area is underlain by undifferentiated Precambrian

crystalline rocks, and the bedrock under the eastern part of the

area consists of numerous Cambrian-age sandstone and shale

sedimentary units.

Climate

The average annual precipitation in this area is 23 to 29

inches (585 to 735 millimeters). About 77 percent of the

precipitation falls as rain during the growing season (May

through September), and about 17 percent falls as snow. The

average annual temperature is 39 to 44 degrees F (4 to 6

degrees C). The freeze-free period averages about 155 days and

ranges from 135 to 175 days. It is longest in the southern part of

the MLRA.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 5.7%; ground water, 3.6%

Livestock—surface water, 0.3%; ground water, 0.9%

Irrigation—surface water, 16.9%; ground water, 72.6%

Other—surface water, 0.0%; ground water, 0.0%
282 Major Land Resource Areas

91B—Wisconsin and Minnesota Sandy

Outwash

This area (shown in fig. 91B–1) is in Wisconsin (60 percent)

and Minnesota (40 percent). It makes up about 4,110 square

miles (10,650 square kilometers). The cities and towns of

The total withdrawals average 39 million gallons per day

(150 million liters per day). About 77 percent is from ground

water sources, and 23 percent is from surface water sources.

Surface water occurs in all parts of the MLRA. It is most

abundant in the western half. In years of normal precipitation,

the moderate precipitation is inadequate for crops and pasture

on sandy soils. In years of little or no precipitation, crop yields

are seriously reduced. Irrigation is widely used for high-value

crops. Drainage of the wet lowland soils is needed for good

crop production. The surface water is generally of good quality

and is suitable for almost all uses.

Ground water is abundant in unconsolidated sand and gravel

in the surficial drift and buried drift aquifers throughout this

area. The deposits may be discontinuous in the buried drift,

where lenses of sand and gravel are separated by lenses of till.

The till helps to protect the buried drift aquifer from

contamination from surface activities. The two aquifers have

water with median levels of 350 and 450 parts per million

(milligrams per liter) total dissolved solids, respectively. Both

aquifers have calcium-magnesium-bicarbonate type water that

is hard. The median level of iron in the buried drift aquifer

exceeds 1,000 parts per billion (micrograms per liter), which is

over three times the secondary standard for esthetics in

drinking water. Except for these iron levels, the ground water is

of good quality and is suitable for all uses with minimal

treatment.

Good-quality ground water is available from a number of

sedimentary rocks in the eastern half of this area. These aquifers

include the St. Peter and Prairie du Chien sandstone and

dolomite, the Ironton-Galesville sandstone, and the Mount

Simon-Hinckley sandstone. The water from these aquifers

averages about 250 to 350 parts per million (milligrams per

liter) total dissolved solids. All of these aquifers have calciummagnesium-bicarbonate type of water that is hard. They

provide water primarily for municipal and industrial uses. The

St. Peter aquifer is not utilized much in this area because good

aquifers occur above it.

Soils

The dominant soil orders in this MLRA are Mollisols and

Histosols. The soils have a frigid soil temperature regime in the

northern part of the area and a mesic soil temperature regime in

the extreme southern part. They have a udic or aquic soil

moisture regime and mixed mineralogy. The soils on uplands

generally are well drained to excessively drained. Very poorly

drained Histosols are in basins and depressions. Hapludolls

(Arvilla, Estherville, and Fairhaven series) and Argiudolls

(Dorset, Malardi, and Verndale series) formed in outwash

mantled with loamy material. They are on outwash plains and

stream terraces. Hapludolls (Hawick, Hubbard, Sandberg, and

Sparta series) formed in outwash on outwash plains and stream

terraces. Haplosaprists (Houghton, Markey, and Seelyeville

series) formed in organic material in basins and depressions.

Biological Resources

Historically, jack pine mixed with pin oak and bur oak grew

on well drained soils on the outwash plains in this area. Oak

savanna occurred in much of the area. Black spruce, tamarack,

white cedar, and black ash were prominent on poorly drained

and very poorly drained soils.

Some of the major wildlife species in this area are whitetailed deer, black bear, ruffed grouse, and sharp-tailed grouse.

Because of its relatively unaltered landscape, this MLRA

supports a high percentage of the rare plants and animals that

occur in Minnesota.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 46%

Grassland—private, 10%

Forest—private, 15%; Federal, 1%

Urban development—private, 5%

Water—private, 13%

Other—private, 10%

The cropland in this MLRA is used mainly for feed grains

and forage for livestock. Irrigation is common in some areas

where corn, soybeans, potatoes, and canning crops, such as

snap beans, peas, and corn, are grown. Without irrigation,

droughtiness limits crop selection and yields in many areas.

Dairy and beef operations are common. The forestland in the

area is used mainly for pulp and timber production.

Recreational hunting and fishing are important activities in the

MLRA, especially in the northern part, which is forested.

The major resource concerns are water quality, nutrient

management, improperly managed grazing, and wind erosion.

Conservation practices on cropland generally include

conservation crop rotations, crop residue management, and

field windbreaks, all of which help to control wind erosion.

Nutrient management and pest management are important

because of water-quality concerns, especially on sandy soils

and in areas where irrigated vegetable crops are grown. Pasture

and hayland planting and prescribed grazing improve pastures

and grazing management. Forest stand improvement and forest

trails and landings reduce the impact of timber management

activities on water quality. 
of the United States 283

Figure 91B-1: Location of MLRA 91B in Land Resource Region K.

consists of Keweenawan sandstone in the northern part of the

area and Cambrian sandstone with dolomite and shale in the

southern part. In most areas the bedrock is covered by

Pleistocene deposits as much as 330 feet (100 meters) thick.

Bedrock exposures occur in some areas along the St. Croix

River. Most of the Pleistocene deposits are late Wisconsin in

age.

Climate

The average annual precipitation in this area is 25 to 34

inches (635 to 865 millimeters). About two-thirds of the

rainfall occurs as convective thunderstorms during the growing

season (May through September). Snowfall generally occurs

from October through April. The average annual temperature is

38 to 46 degrees F (3 to 8 degrees C). The freeze-free period

averages about 150 days and generally ranges from 120 to 180

days. It can be as short as 90 days in the northern part of the

area.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 6.3%; ground water, 6.4%

Livestock—surface water, 0.3%; ground water, 0.2%

Irrigation—surface water, 1.2%; ground water, 5.5%

Other—surface water, 74.8%; ground water, 5.3%

The total withdrawals average 570 million gallons per day

(2,155 million liters per day). About 17 percent is from ground

water sources, and 83 percent is from surface water sources.

Surface water and ground water are very abundant and readily

available. In years of normal precipitation, the moderate

precipitation is inadequate for crops and pasture on sandy soils.

In years of little or no precipitation, crop yields are seriously

reduced. Drainage of the wet soils on lowlands is needed for the

field crops and tame pasture plants commonly grown in the

area. Irrigation is widely used for high-value crops. The sources

of surface water are the many lakes and streams. The surface

water is used mostly for recreational activities in the part of this

area in Wisconsin, but it is used for public supply and

municipal and industrial purposes in the part in Minnesota.

Water quality is generally good. Most of the lakes and streams

are clear, but those that receive deposits of organic material

from wetland vegetation are tinted brown.

This MLRA has three types of lakes—spring lakes, seepage

lakes, and drainage lakes. Spring lakes seldom have an inlet,

but they have an outlet with substantial flow. They are fed by

ground water. Seepage lakes generally do not have an inlet or

an outlet but may have an intermittent outlet. The water level is

maintained by the water table or a well sealed bottom. Drainage

lakes have an outlet and at least one inlet. Their main water

source is runoff from streams. Spring lakes have a high mineral

Spooner, Grantsburg, Solon Springs, and Siren, Wisconsin,

and North Branch, Princeton, and Zimmerman, Minnesota, are

in this MLRA. Interstates 35 and 94 cross the area. Some of

the Chequamegon National Forest is in the far northern part of

the area. All of the Crex Meadows Wildlife Area is in this

MLRA.

Physiography

The eastern half of this area is in the Superior Upland

Province of the Laurentian Upland, and the western half is in

the Western Lake Section of the Central Lowland Province of

the Interior Plains. Much of the area is nearly level to gently

sloping, but some steeper escarpments occur along streams,

rivers, and lake borders. The area is characterized by outwash

plains, some of which are pitted or collapsed, and by small

moraines, dunes, lake plains, swamps, bogs, and marshes.

Lakes are common, and streams generally form a dendritic

pattern. Elevation ranges from about 800 feet (245 meters) to

1,500 feet (455 meters). Local relief typically is only a few

meters.

The extent of the major Hydrologic Unit Areas (identified

by four-digit numbers) that make up this MLRA is as follows:

St. Croix (0703), 69 percent; Mississippi Headwaters (0701), 20

percent; and Western Lake Superior (0401), 11 percent. The St.

Croix, Namekagon, Rum, and Yellow Rivers are major rivers

that drain this MLRA. The St. Croix River is a National Scenic

River, and the Rum River is a National Wild and Scenic River.

Geology

Precambrian and Cambrian sandstone bedrock underlies

most of the glacial deposits in this MLRA. The bedrock
284 Major Land Resource Areas

content because they receive the greatest amount of ground

water. Drainage lakes have a lower mineral content than the

spring lakes, and seepage lakes have a very low mineral

content. Drainage lakes have the greatest range in reaction.

Water in the spring lakes has reaction similar to that of the

ground water. Seepage lakes commonly are acid, and some of

the drainage lakes are alkaline. About 80 percent of the lakes

are acid, having a pH of less than 7.0. The rest are neutral or

alkaline, having a pH of 7.0 or higher.

Glacial deposits are the primary sources of ground water.

Ground water supplies meet domestic, agricultural, municipal,

and industrial needs. The quality of the water is good. The level

of total dissolved solids is less than 150 parts per million

(milligrams per liter). The main components in the water are

calcium, magnesium, and bicarbonate ions. Locally, the

dissolved mineral content may be relatively high because of a

high content of limestone in the glacial deposits. Minor

problems may be caused by hardness and in some areas by high

concentrations of iron. Pollution of surface water is minimal

because the area is relatively undeveloped and there is little

municipal or industrial waste. Extensive building of cottages

and houses along the lakes and streams is a potential problem.

Effluent from sewage disposal facilities can pollute the water

and result in the growth of weeds and algae. The problem is

especially severe in seepage lakes, where there is little water

exchange. Ground water yields from all the aquifers range from

100 to more than 1,000 gallons per minute (380 to more than

3,785 liters per minute).

Good-quality ground water is available from a number of

sedimentary rocks in the part of this MLRA in Minnesota.

These aquifers include the St. Peter and Prairie du Chien

sandstone and dolomite, the Ironton-Galesville sandstone, and

the Mount Simon-Hinckley sandstone. The level of total

dissolved solids averages about 250 to 350 parts per million

(milligrams per liter). All of these aquifers have a calciummagnesium-bicarbonate type of water that is hard. They

provide water primarily for municipal and industrial uses. The

St. Peter aquifer is not utilized much in this area because good

aquifers occur above it.

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, Histosols, and Spodosols. The soils have a frigid soil

temperature regime, a udic or aquic soil moisture regime, and

mixed or isotic mineralogy. The soils on uplands are very deep,

excessively drained to somewhat poorly drained, and sandy.

The soils on lowlands are very deep, poorly drained or very

poorly drained, and sandy or mucky. Udipsamments (Cantlin,

Graycalm, Grayling, Menahga, Mahtomedi, Grettum,

Friendship, Wurtsmith, Zimmerman, Shawano, Crex, and Lino

series) and Haplorthods (Croswell, Rubicon, Vilas, and Sayner

series) formed in sandy outwash or windblown sediments.

Hapludalfs formed in sandy outwash or windblown sediments

over lacustrine clay on old glacial lake plains (Karlsborg,

Meenon, and Perida series) or in sandy-skeletal alluvium along

the major rivers (Dairyland and Bigisland series).

Psammaquents (Newson series) and Endoaquods (Kinross and

Au Gres series) formed in sandy outwash in depressions on

outwash plains. Haplosaprists formed in sapric material in

marshes (Markey and Seelyeville series) and in bogs (Dawson

and Loxley series). The soils on flood plains include

Udipsamments (Winterfield series) and Fluvaquents (Totagatic

series), which formed in sandy alluvium, and Haplosaprists

(Bowstring series), which formed in sapric material.

Biological Resources

This area is in a mixed coniferous-deciduous forest. Jack

pine and scrub (Hill’s) oak are the dominant trees. Barrens are

common. Poorly drained soils support black spruce, tamarack,

speckled alder, willow, and sedges.

Some of the major wildlife species in this area are whitetailed deer, black bear, eastern gray wolf, ruffed grouse, sharptailed grouse, woodcock, gray squirrel, red squirrel, snowshoe

hare, porcupine, ducks, and geese. Red fox, bobcat, coyote,

muskrat, fisher, mink, otter, raccoon, and beaver are the main

furbearers. Private and public forestland mixed with scattered

cropland provides substantial wildlife habitat. Fishing occurs in

the many lakes and rivers. Local species include rainbow trout,

brook trout, walleye pike, largemouth bass, smallmouth bass,

bluegill, black crappie, yellow perch, musky, and northern pike.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 20%

Grassland—private, 7%; Federal, 1%

Forest—private, 43%; Federal, 3%

Urban development—private, 11%

Water—private, 6%; Federal, 1%

Other—private, 8%

Nearly 50 percent of this MLRA is forested. Two-thirds of

the forestland consists of national and State forests and large,

privately owned holdings, and one-third consists of small,

privately owned holdings. The forestland is primarily in the

eastern part of the MLRA, and it supports a pulp and timber

industry and is used for recreational activities. About 28

percent of the MLRA, mostly in the western part, is used for

agriculture. Irrigated corn, soybeans, and vegetable crops (such

as potatoes, snap beans, and peas) and forage and feed grains
of the United States 285

for dairy cattle and other livestock are the principal crops.

Other vegetable and fruit crops also are grown. Cranberries are

grown on some wet soils. A substantial acreage in the MLRA,

mainly in the southern part, is urban land. The urban areas are

expanding rapidly.

The major resource management concerns in this area are

water erosion, wind erosion, wetness, soil fertility, soil tilth, and

water quality. Conservation practices on cropland generally

include conservation crop rotations and crop residue

management, which help to control water erosion and wind

erosion. Cover crops are sometimes planted with low-residue

canning crops. Nutrient management and pest management are

important because of water-quality concerns, especially on

irrigated cropland. Prescribed grazing and pasture and hayland

planting improve pastures and grazing management. Forest

stand improvement and forest trails and landings reduce the

impacts of timber management activities on the quality of

surface water and ground water. 

Figure 92-1: Location of MLRA 92 in Land Resource Region K.

92—Superior Lake Plain

This area (shown in fig. 92-1) is in Wisconsin (48 percent),

Michigan (39 percent), and Minnesota (13 percent). It makes up

about 2,920 square miles (7,570 square kilometers). The cities

of Duluth, Minnesota, Superior, and Ashland, Wisconsin, and

Ontonagon, Michigan, are in this MLRA. Interstate 35 ends in

Duluth. A large part of the Ottawa National Forest is in the

eastern half of this area. The Ontonagon, Bad River, and Red

Cliff Indian Reservations are in the area. Numerous State parks

and State forests are throughout the area. The Apostle Islands

National Lakeshore is in this MLRA.

Physiography

All of this area is in the Superior Upland Province of the

Laurentian Upland. The area is characterized by a till plain

mixed with lake plains, lake terraces, beaches, flood plains,

swamps, and marshes. Some rocky knobs, hills, and low

mountains make up part of this nearly level lake plain.

Elevation ranges from 600 to 1,400 feet (185 to 425 meters),

increasing gradually from the lakeshore inland. Local relief on

the lake plain is only 3 to 6 feet (1 to 2 meters), but the

adjoining hills and low mountains rise sharply from 85 feet (25

meters) to more than 330 feet (100 meters) above the plains.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Western Lake Superior (0401), 60 percent, and Southern Lake

Superior-Lake Superior (0402), 40 percent. Some of the

streams crossing this area and emptying into Lake Superior are

the Bois Brule, Nemadji, Whittlesey, Montreal, Black, Presque

Isle, and Ontonagon Rivers in Wisconsin and Michigan and

numerous steep-gradient streams along the north shore of

Minnesota.

Geology

This area has been glaciated, and most of the surface

deposits are fine textured till derived from glacial lake

sediments. The bedrock in the area is a mixture of late

Precambrian and Cambrian sandstones and shales and mafic

igneous rocks. It is known as the Keweenawan Group in

Wisconsin and Minnesota. The bedrock units in Michigan are

known as the Freda and Jacobsville sandstones, Nonesuch

shale, the Portage Lake volcanics, and the Copper Harbor

conglomerate.

Climate

The average annual precipitation in this area is 27 to 37

inches (685 to 940 millimeters). It is lowest along the lakeshore

and highest in inland areas. The maximum precipitation occurs

as high-intensity, convective thunderstorms in summer, and the

lowest precipitation occurs in midwinter. Precipitation in winter

occurs as snow. The average annual temperature is 38 to 42

degrees F (4 to 6 degrees C). The freeze-free period averages

about 155 days and ranges from 125 to 190 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 3.4%; ground water, 0.0%

Livestock—surface water, 0.7%; ground water, 0.4%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 95.5%; ground water, 0.0%
286 Major Land Resource Areas

The total withdrawals average 155 million gallons per day

(585 million liters per day). Almost 100 percent is from surface

water sources. Precipitation is adequate for crops and pasture.

Drainage of level areas of wet soils is needed for good growth

of crops. The area has few inland lakes, but much of the area has

access to Lake Superior for water supply and recreation. Most

of the “other” water use in this area is for the wood and paper

products industries. Iron ore, limestone, and dolomite are

shipped from the Great Lakes harbors at Duluth, Minnesota,

and Superior, Wisconsin, and some surface water is used in

handling those materials. The surface water is of good quality.

It is hard but is suitable for most uses with little or no treatment.

Two sources of ground water occur in this area. One is the

isolated pockets of unconsolidated sand and gravel in the

glacial drift. The other is the Lake Superior Sandstone and

Precambrian Lava Flows aquifer. Water from both of these

aquifers is moderately hard to very hard and is typically very

low in total dissolved solids, having less than 300 parts per

million (milligrams per liter). About 30 percent of all the wells

tested in these aquifers had iron and manganese concentrations

that exceeded the national secondary standards for drinking

water. These standards are for esthetics and do not affect human

health. Staining and scale-buildup in pipes and on appliances

occur when high amounts of iron and manganese occur in

water.

Soils

The dominant soils in this MLRA are Alfisols, Spodosols,

Inceptisols, and Entisols. The soils in the area have a frigid soil

temperature regime, a udic or aquic soil moisture regime, and

mixed or isotic mineralogy. The major soils formed in clayey to

loamy till in some areas with a sandy mantle. Some soils,

primarily along the edges of the MLRA, have stratified silty and

clayey lacustrine deposits. The soils in some areas along the

shore of Lake Superior formed in organic material or in sandy

beach deposits.

Glossudalfs on till plains formed in very deep clayey or

loamy till (Miskoaki, Amnicon, Cuttre, Odanah, Sanborg,

Badriver, Watton, Flintsteel, and Big Iron series) or in clayey

till that is deep to loamy or sandy lacustrine deposits (Anton,

Borea, Cornucopia, Portwing, and Herbster series). Haplorthods

formed in clayey till mantled with loamy material (Superior,

Ubly, and Belding series), in clayey till mantled with sandy

material (Manistee, Kellogg, and Ashwabay series), and in

loamy till mantled with sandy material (Menominee and

Morganlake series) on till plains and remnant beaches; in silty

lacustrine deposits (Sporley and Fence series) on lake plains

and remnant beaches; in sandy beach, dune, or lacustrine

deposits (Rousseau, Neconish, Vilas, Croswell, Sultz, and

Cublake series) on remnant beaches and dunes; and in clayey,

loamy, and sandy deposits over sandstone bedrock (Lapoin,

Abbaye, Brownstone, and Redrim series) in bedrock-controlled

areas along Lake Superior. Epiaquepts formed in very deep

clayey or loamy till (Bergland, Pickford, and Munuscong

series); in clayey till that is deep to loamy and sandy lacustrine

material (Lerch and Happyhollow series); or in clayey till

mantled with sandy material (Wakeley series) in depressions on

till plains. Haplohemists (Rifle series) formed in organic

deposits in marshes along Lake Superior, and Haplosaprists

(Seelyeville, Cathro, Lupton, Dorval, and Tawas series) formed

in organic deposits in inland swamps and in side-hill seep

areas. Udipsamments (Grayling, Wurtsmith, and Meehan series)

formed in sandy beach and dune deposits on active beaches.

Udifluvents formed in silty alluvium (Moquah series) or sandy

alluvium (Pelkie and Dechamps series) on flood plains.

Biological Resources

This area supports deciduous and evergreen trees. Boreal

forests (aspen, white birch, balsam fir, white spruce, white pine,

red pine, white cedar, and tamarack) and mixed deciduous and

coniferous forests (hemlock, sugar maple, yellow birch, red

pine, and white pine) are dominant. Swamp conifers and

lowland brush commonly grow on the wetter soils.

Some of the major wildlife species in this area include black

bear, white-tailed deer, coyote, snowshoe hare, timber wolf,

ruffed grouse, tree squirrel, bald eagle, and Canada goose. The

species of fish in the area include northern pike, perch, walleye,

largemouth bass, smallmouth bass, brook trout, steelhead trout,

and panfish.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 10%

Grassland—private, 4%

Forest—private, 68%; Federal, 12%

Urban development—private, 3%

Water—private, 1%

Other—private, 2%

More than three-fourths of this area is forested, and about

two-thirds is privately owned forestland used for timber

production and recreation. About one-tenth of the MLRA is

cropland used mainly for small grains and hay for dairy cattle

and other livestock. Apples, blueberries, trefoil seed, and other

specialty crops are important cash crops in some areas. Only a

small part of the land is used for pasture.

The major soil resource management concerns are water

erosion, wetness, soil fertility, and soil tilth. Conservation

practices on cropland generally include crop rotations,

conservation tillage systems, and grassed waterways. Surface

drainage systems are needed to remove surface water from wet

areas. 
of the United States 287

Figure 93A-1: Location of MLRA 93A in Land Resource Region K.

93A—Superior Stony and Rocky Loamy

Plains and Hills, Western Part

This area is entirely in northeast Minnesota (fig. 93A-1). It

makes up about 8,570 square miles (22,205 square kilometers).

The towns of Ely, Finland, Grand Marais, Two Harbors, and

Cloquet are in this MLRA. The main highways through the area

are U.S. Highway 53 and Minnesota Highways 1 and 61. Most

of the area is in the Superior National Forest, and the Boundary

Waters Canoe Area Wilderness is in this MLRA. Because of its

shape, this area is called the “Arrowhead region” of Minnesota.

The Grand Portage Indian Reservation is at the tip of the

“arrowhead.” Part of the Fond du Lac Indian Reservation is in

the southeast tip of the area, and the Vermilion Lake Indian

Reservation is in the central part of the area.

Physiography

This area is in the Superior Upland Province of the

Laurentian Upland. It was glaciated by numerous advances of

the Superior, Rainy, and Des Moines glacial lobes during the

Wisconsin and pre-Wisconsin glacial periods. Most of the

surface of this area is young, dominated by drumlin fields,

moraines, small glacial lake plains, outwash plains, and

bedrock-controlled uplands. Elevation generally ranges from

about 600 to 2,100 feet (185 to 640 meters). Eagle Mountain, at

an elevation of 2,301 feet (701 meters), is the highest point in

Minnesota. Closed depressions, lakes, ponds, and bogs are

throughout the area. The several thousand lakes within the

Boundary Waters Canoe Area Wilderness were formed by the

scouring of the bedrock landscape by glacial ice. Local relief

ranges from 10 to more than 100 feet (3 to 30 meters). It can be

600 feet (185 meters) or more in some areas adjacent to Lake

Superior.

The extent of the major Hydrologic Unit Areas (identified by

four digit numbers) that make up the MLRA is as follows:

Rainy (0903), 53 percent; Western Lake Superior (0401), 45

percent; Mississippi Headwaters (0701), 1 percent; and St.

Croix (0703), 1 percent. The surface drainage network in this

area is immature. It is made up primarily of remnants of glacial

meltwater channels. The major channels are occupied by the

Vermilion, Whiteface, and St. Louis Rivers. Many small

tributaries drain into Lake Superior from the uplands to the

west, including the Lester, Baptism, and Temperance Rivers.

Geology

This area is covered by glacial till, drift, and outwash and by

lake sediments, alluvium, and thin layers of loess. These

deposits range from only a few inches to several hundred feet in

thickness. Bedrock is on the surface or at a shallow depth in

many areas. The bedrock formations in this area include Middle

Precambrian graywacke and mudstone and their metamorphic

equivalents, Upper Precambrian basalts, gabbroic rocks,

including the Duluth complex, and Lower Precambrian

granitics, metabasalt, and graywacke. Iron ore is mined in this

area.

Climate

The average annual precipitation in almost all of this area is

25 to 30 inches (635 to 760 millimeters). It is as much as 33

inches (840 millimeters) at the tip of the “arrowhead.” About 65

percent of the precipitation falls as rain during the growing

season (May through September), and about 21 percent falls as

snow. The average annual temperature is 36 to 40 degrees F (2

to 4 degrees C). The freeze-free period averages about 150 days

and ranges from 120 to 175 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 8.4%; ground water, 0.0%

Livestock—surface water, 4.2%; ground water, 9.1%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 78.3%; ground water, 0.0%

The total withdrawals average 19 million gallons per day (72

million liters per day). About 9 percent is from ground water

sources, and 91 percent is from surface water sources. The

numerous lakes and streams are sources of water. The timber

and mining industries use most of the surface water that is used

in this area. This water is of very good quality and is suitable

for most uses.
288 Major Land Resource Areas

93B—Superior Stony and Rocky Loamy

Plains and Hills, Eastern Part

This area (shown in fig. 93B-1) is in Michigan (86 percent)

and Wisconsin (14 percent). It makes up about 6,900 square

miles (17,880 square kilometers). The cities of Hurley and

Mellen, Wisconsin, and Munising, Marquette, Houghton,

Baraga, and Ironwood, Michigan, are in this MLRA. U.S.

Highways 2, 41, and 45 cross the area. The K.I. Sawyer Air

Force Base is in this area. The L’Anse, Keweenaw Bay, and Lac

Vieux Desert Indian Reservations are in the part of the

area in Michigan. The MLRA includes parts of the Ottawa

and Hiawatha National Forests and parts of the Escanaba

River, Copper Country, Baraga, and Lake Superior State

Forests in Michigan; the Chequamegon National Forest in

Wisconsin; and Isle Royale National Park, which is offshore in

Lake Superior.

Ground water occurs in joints, fractures, and bedding planes

in the Precambrian crystalline rocks underlying most of this

area. This water typically has more than 500 parts per million

(milligrams per liter) total dissolved solids and is hard. The

median level of iron exceeds the national secondary standard

for drinking water of 300 parts per billion (micrograms per

liter). This aquifer may be the only source of ground water for

domestic use and livestock in most of this area. Volcanic rocks

along the shore of Lake Superior also contain ground water.

The water in these basalt flows generally has a median level of

total dissolved solids of about 200 parts per million (milligrams

per liter) and is moderately hard. This aquifer provides water

mostly for domestic use and livestock. Naturally occurring

areas with very saline water are not used.

Soils

This MLRA is dominated by Entisols, Inceptisols, and

Histosols. The soils have a frigid soil temperature regime, a

udic soil moisture regime, and isotic or mixed mineralogy. The

parent material is dominantly dense loamy till, coarse glacial

drift and outwash, silty glaciolacustrine sediment, local loess,

alluvium, and organic material. The soils are dominantly

shallow or moderately deep in the northern part of the area and

very deep in the southern part. They are very poorly drained to

excessively drained and are level to very steep. Eutrudepts

(Ahmeek, Brimson, Eveleth, Hermantown, Normanna, and

Toimi series) formed in till. Dystrudepts (Conic, Insula, and

Mesaba series) formed in till over bedrock. Udorthents (Quetico

series) formed in loamy and very shallow loamy material over

bedrock. Udipsamments (Grayling and Mahtomedi series)

formed in sandy outwash. Haplohemists (Rifle and Greenwood

series) formed in thick layers of organic material.

Biological Resources

This MLRA makes up the true forested region of Minnesota.

Prior to settlement, the vegetation consisted almost entirely of

forest communities. The forest types included white pine-red

pine forest, aspen-birch forest, mixed hardwood-pine forest

with sugar maple on ridges, and jack pine barrens in the

uplands. Conifer swamps or bogs occupied the depressions and

areas of outwash. Fire dependence characterizes all of these

forest types. This MLRA is still dominantly forested. Much of

the land is in public ownership and managed for wood products

and recreation. Many areas on uplands support quaking aspen

and paper birch. Some scattered areas have old-growth pine

stands.

Some of the major wildlife species in this area are whitetailed deer, moose, and ruffed grouse. Because of its relatively

unaltered landscape, this MLRA supports a high percentage of

the rare plants and animals that occur in Minnesota. Such

species include the bald eagle, the Canada lynx, and the eastern

timber wolf. The thousands of kettle and bog lakes in this area

support populations of common game fish, such as walleye,

northern pike, and smallmouth bass. Numerous short, highgradient streams lead directly from the highlands to the shores

of Lake Superior. These cold-water streams support native,

sustaining populations of brook trout and rainbow trout and also

serve as breeding waters for several species of anadromous fish

common to Lake Superior, including steelhead trout and lake

trout.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 1%

Forest—private, 44%; Federal, 31%

Urban development—private, 2%

Water—private, 10%; Federal, 8%

Other—private, 2%; Federal, 2%

About 75 percent of this MLRA is forested, and nearly all of

the forestland consists of county, State, or national forests.

Lumbering, iron mining, and recreation are important. The

many bodies of surface water in the area provide opportunities

for recreation.

The major resource concerns include the water erosion and

reduced water quality caused by timber harvesting. They also

include management of wildlife habitat and riparian areas.

Conservation practices on forestland generally include forest

stand improvement and forest trails and landings. These

practices reduce the impacts of timber management activities

on water quality. Riparian forest buffers help to protect streams

and rivers from timber harvesting activities, improve wildlife

habitat, and protect water quality. 
of the United States 289

The surface of the area is covered by glacial till derived from

these bedrock types, glaciofluvial deposits of very diverse

origin, and organic deposits.

Climate

The average annual precipitation ranges from 30 to 38

inches (760 to 965 millimeters) in most of this area. It is 26 to

30 inches (660 to 760 millimeters) just inland from

Chequamegon Bay in Wisconsin and Keweenaw Bay in

Michigan. About two-thirds of the rainfall occurs as highintensity, convective thunderstorms during the growing season.

Snow is common in winter. The average annual snowfall is

more than 200 inches (510 centimeters) in the areas adjacent to

Lake Superior. The average annual temperature is 38 to 43

degrees F (3 to 6 degrees C). The freeze-free period averages

about 140 days and ranges from 100 to 180 days. It is longest

adjacent to Lake Superior and shortest in inland areas that are

farthest from the Great Lakes, in the part of the MLRA in

Michigan.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 73.0%; ground water, 8.3%

Livestock—surface water, 8.6%; ground water, 10.1%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 0.0%; ground water, 0.0%

The total withdrawals average 6 million gallons per day (23

million liters per day). About 18 percent is from ground water

sources, and 82 percent is from surface water sources. Lake

Superior and the numerous inland lakes and streams in this

MLRA are the sources of surface water. This water is of good

quality and is suitable for almost all uses.

Ground water can be obtained from glacial deposits in most

of this area, except for a large part of the northern half. The

water is in sand and gravel outwash, in silty and sandy glacial

lake sediments, and in buried sand and gravel lenses within the

glacial till. The water is of good quality and is suitable for

almost all uses with minimal treatment. It typically has about

200 to 250 parts per million (milligrams per liter) total

dissolved solids. The water from some wells has very high

levels of iron, especially in the southern half of the area.

A Precambrian Sandstone aquifer occurs south and west of

Keweenaw Bay, in the part of this area in Michigan. Little

water-quality data are available for this aquifer. The Lake

Superior Sandstone and Precambrian lava flow aquifers occur in

the southwestern part of this area, in Wisconsin. Water from

these aquifers is very similar in quality to the water in the

glacial deposits.

Figure 93B-1: Location of MLRA 93B in Land Resource Region K.

Physiography

This area is almost entirely in the Superior Upland Province

of the Laurentian Upland. The eastern end of the area is in the

Eastern Lake Section of the Central Lowland Province of the

Interior Plains. This area has many glacial landscape features

and is dissected by numerous streams and rivers. It is

characterized by a mixture of high-relief bedrock-controlled

moraines, end moraines, and ground moraines and nearly level

areas of glaciofluvial deposits. Elevation generally ranges from

600 to 1,970 feet (185 to 600 meters). Mt. Arvon, the highest

point in Michigan, rises to an elevation of 1,979 feet (603

meters). The peaks of some bedrock-controlled moraines in the

steeper areas rise more than 300 feet (90 meters) above the

adjacent lowlands.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Southern Lake Superior-Lake Superior (0402), 67 percent;

Northwestern Lake Michigan (0403), 20 percent; Western Lake

Superior (0401), 11 percent; and Chippewa (0705), 2 percent.

Numerous rivers drain this MLRA, and many of the rivers, such

as the Escanaba, Paint, Michigamme, and Fence Rivers in

Michigan, empty into Lake Michigan. The Chocolay, Sturgeon,

Ontonagon, Montreal, and Presque Isle Rivers in Michigan

drain into Lake Superior.

Geology

This area is underlain dominantly by Precambrian igneous

or metamorphic bedrock that contains significant amounts of

commercially valuable iron and copper. A smaller percentage of

the area is underlain by Cambrian or Precambrian sandstone.
290 Major Land Resource Areas

94A—Northern Michigan and Wisconsin

Sandy Drift

This area is entirely in the northern part of the Lower

Peninsula of Michigan (fig. 94A-1). It makes up 9,020 square

miles (23,380 square kilometers). The towns of Grayling,

Gaylord, Cadillac, Clare, and Tawas City are in this MLRA.

Interstate 75 and U.S. Highways 10, 23, 27, and 131 pass

through the area. Parts of the Au Sable, Mackinaw, and Pere

Marquette State Forests and the Huron and Manistee National

Forests occur in the area.

Physiography

This area is in the Eastern Lake Section of the Central

Lowland Province of the Interior Plains. It is dominated by

outwash plains and moraines. Scattered lake plains and till

Soils

The dominant soil orders in this MLRA are Histosols and

Spodosols. The soils in the area dominantly have a frigid soil

temperature regime, an aquic or udic soil moisture regime, and

mixed or isotic mineralogy. They are shallow to very deep,

excessively drained to very poorly drained, and sandy to

clayey. Haplorthods (Amasa, Sundog, Pence, Padus, and

Channing series) formed in loess over outwash on outwash

plains, valley trains, and kames. Fragiorthods (Gogebic,

Munising, Wabeno, Champion, and Schweitzer series) formed

in till or loess over till on till plains and moraines. Haplorthods

formed in sandy glacial deposits on outwash plains, valley

trains, and moraines (Kalkaska, Karlin, Croswell, Au Gres, and

Rubicon series), in till or loess over till (Sarona series), in till

over igneous or metamorphic bedrock (Peshekee, Michigamme,

Dishno, and Arcadian series), and in sandy eolian deposits

(Rousseau and Deer Park series) on dunes and lake plains.

Haplosaprists (Carbondale, Cathro, Lupton, Markey, and Tawas

series) formed in organic material in depressions on lake plains,

outwash plains, and till plains.

Biological Resources

The soils on uplands in this area support natural stands of

mixed northern hardwoods and pine. Sugar maple, oak, white

ash, elm, yellow birch, white pine, jack pine, and red pine are

the principal tree species. Lowland areas support both mixed

hardwoods and conifers. Elm, soft maple, black ash, black

spruce, tamarack, and northern white-cedar are the major

species.

Some of the major wildlife species in this area are whitetailed deer, black bear, red fox, raccoon, muskrat, cottontail

rabbit, snowshoe hare, squirrel, pheasant, ruffed grouse,

woodcock, mallard, blue-winged teal, and wood duck. Fishing

occurs in Lake Superior, in other lakes, and in streams and

rivers. The species of fish in the area include lake trout, rainbow

trout, brook trout, walleye pike, largemouth bass, smallmouth

bass, bluegill, black crappie, yellow perch, and northern pike.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 2%

Grassland—private, 1%

Forest—private, 68%; Federal, 20%

Urban development—private, 2%

Water—private, 3%; Federal, 2%

Other—private, 2%

Almost nine-tenths of this MLRA is forested, and nearly

four-fifths of the forestland is privately owned. Feed grains and

hay are the chief crops grown on the limited acreage used as

cropland. Much of the grain is fed to dairy cattle and other

livestock on the farms where it is grown. The rest of the

farmland in the area is about equally divided between pasture

and farm woodlots. Recreation is an important land use,

especially along the major streams and on sites bordering Lake

Superior.

The major soil resource management concerns are water

erosion, soil wetness, soil fertility, and soil tilth. Conservation

practices on cropland generally include crop rotations,

conservation tillage systems (especially no-till systems),

contour farming, contour stripcropping, and grassed waterways.

A combination of surface and subsurface drainage systems is

needed in most areas of poorly drained soils. 

Figure 94A-1: Location of MLRA 94A in Land Resource Region K.
of the United States 291

and lakes, which generally have a calcium bicarbonate type of

water but can have high levels of dissolved solids. The surface

water is of good quality and is suitable for almost all uses with

minimal treatment.

Glacial deposits are the sole sources of ground water in this

MLRA. The sedimentary rocks that underlie the glacial

deposits are mostly shale and are not used as sources of water.

Of the glacial deposits, outwash and lakebed sands are the most

productive aquifers. Calcium and bicarbonate are the principal

dissolved substances in the ground water. The median level of

total dissolved solids is less than 200 parts per million

(milligrams per liter). The ground water is hard and can have

high levels of iron. Problems with nitrate contamination are

related to land use practices, such as applications of fertilizer,

manure management, and septic systems.

Soils

The dominant soils in this MLRA are Spodosols, Entisols,

Alfisols, and Histosols. These soils have a frigid soil

temperature regime, an aquic or udic soil moisture regime, and

dominantly mixed mineralogy. They are very deep, excessively

drained to poorly drained, and sandy. Nearly level to very steep

Haplorthods (Rubicon, Kalkaska, and Blue Lake series) and

Udipsamments (Graycalm and Grayling series) formed in sandy

glaciofluvial deposits. Nearly level to very steep Glossudalfs

(Klacking and Millersburg series) formed in sandy and loamy

glacial till. Very poorly drained Haplosaprists (Tawas and

Lupton series) formed in thick organic deposits or in organic

deposits over sandy glaciofluvial material.

Biological Resources

This area is a large part of the Northern Lower Michigan

Ecosystem Region and consists mainly of two major forest

community types—the Pine Barrens and the Northern

Hardwoods. Red pine, jack pine, white pine, white oak, black

oak, and red maple formerly were and currently are the

dominant species in the Pine Barrens. Sugar maple, beech,

white pine, and yellow birch formerly were and currently are

the dominant native species in the Northern Hardwoods. Other

important native species include pin cherry, striped maple, and

basswood in the uplands and balsam fir, eastern hemlock,

speckled alder, and black spruce in the mosaic of wetlands

throughout the area.

Some of the major wildlife species in the area are whitetailed deer, elk, black bear, snowshoe hare, coyote, ruffed

grouse, woodcock, woodland songbirds, ducks, and geese. The

species of fish in the numerous lakes, impoundments, rivers,

and streams throughout the area include rainbow trout, brown

trout, brook trout, Chinook salmon, coho salmon, northern

pike, bass, yellow perch, bluegill, and sunfish.

plains are throughout the area. The terrain can be steep on the

moraines and flat in the areas of outwash and lake plains.

Elevation ranges from 850 to 1,725 feet (260 to 525 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Northwestern Lake Huron (0407), 40 percent; Northeastern

Lake Michigan-Lake Michigan (0406), 39 percent; and

Southwestern Lake Huron-Lake Huron (0408), 21 percent. The

Au Sable, Manistee, Au Gres, and Pine Rivers are the major

streams draining this MLRA. Reaches of the Pigeon, Boardman,

Au Sable, Betsie, Rifle, and Pere Marquette Rivers in this area

are National Wild and Scenic Rivers.

Geology

This area is covered almost entirely by deposits of glacial

till, outwash, and lake sediments. Bedrock consisting of

Devonian limestone and dolomite with interbedded shale, chert,

and anhydrite stringers is at various depths below the surface

because of the curvature of the Michigan basin. Bedrock

exposures are evident on the eastern and western shores in the

MLRA, in areas where the outer edges of the basin rise to the

surface.

Climate

The average annual precipitation is 27 to 30 inches (685 to

760 millimeters) in the eastern two-thirds of this area and 30 to

36 inches (760 to 915 millimeters) in the western one-third. The

precipitation occurs as rain during the growing season and

snow during the winter. The average annual snowfall is 45 to

150 inches (115 to 380 centimeters). Most of the precipitation

comes from the west as storms pick up moisture from the Great

Lakes. The average annual temperature is 41 to 47 degrees F (5

to 9 degrees C). The freeze-free period averages about 145 days

and ranges from 105 to 185 days. The average annual air

temperature is lower and the freeze-free period is shorter in most

of the western half of this area than in the rest of the area.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 62.7%; ground water, 14.4%

Livestock—surface water, 0.7%; ground water, 1.2%

Irrigation—surface water, 11.7%; ground water, 4.5%

Other—surface water, 3.4%; ground water, 1.4%

The total withdrawals average 145 million gallons per day

(550 million liters per day). About 22 percent is from ground

water sources, and 78 percent is from surface water sources. This

MLRA is a water-rich area. It is bordered on two sides by the

Great Lakes. Also, it has many high-quality cold-water streams
292 Major Land Resource Areas

94B—Michigan Eastern Upper Peninsula

Sandy Drift

This area (shown in fig. 94B-1) is in Michigan (83 percent)

and Wisconsin (17 percent). It makes up about 9,810 square

miles (25,425 square kilometers). The cities of Shawano,

Keshena, Pembine, and Wausaukee, Wisconsin, and

Menominee, Iron Mountain, Escanaba, Manistique, St. Ignace,

Newberry, Seney, Grand Marais, and Sault Ste. Marie,

Michigan, are in this MLRA. Interstate 75 terminates in Sault

Ste. Marie, and U.S. Highways 2 and 41 cross most of the area.

The Menominee and Bay Mills Indian Reservations are in the

parts of the area in Wisconsin and Michigan, respectively. The

Hiawatha National Forest, parts of the Copper Country,

Escanaba River, and Lake Superior State Forests in Michigan,

and the Nicolet National Forest in Wisconsin also occur in the

area. Most of this area is in the part of Michigan known as the

“Upper Peninsula.” Mackinac Island is included in the area, and

part of the Mackinaw State Forest is on the island.

Physiography

Most of this area is in the Eastern Lake Section of the

Central Lowland Province of the Interior Plains. The western

one-fifth is in the Superior Upland Province of the Laurentian

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 8%

Grassland—private, 8%; Federal, 1%

Forest—private, 59%; Federal, 11%

Urban development—private, 5%

Water—private, 2%; Federal, 1%

Other—private, 5%

About 70 percent of this area is forested, and about 15

percent is cropland or hayland. About one-third of the area is in

small, privately owned holdings, and another one-third consists

of national and State forests. The forests are used mainly for

timber production and recreation. Dairy and beef operations are

very important enterprises in the area. Forage and feed grains

for dairy cattle and other livestock are the principal crops.

Wheat, oats, corn, potatoes, and hay also are grown in the area.

The major soil resource concerns are wind erosion, water

erosion, excessive soil wetness, soil moisture management, and

maintenance of the fertility and productivity of the soils.

Conservation practices on cropland generally include crop

residue management systems (especially no-till and reduced-till

systems), cover crops, wind barriers, stripcropping, and nutrient

management. 

Figure 94B-1: Location of MLRA 94B in Land Resource Region K.

Upland. The area has many glacial landscape features and is

dissected by numerous streams and rivers. It is characterized by

a mixture of low-relief ground moraines, lacustrine deposits,

and glaciofluvial deposits and some higher relief, bedrockcontrolled moraines in the extreme southwest part. Elevation

ranges from 580 to 1,400 feet (175 to 425 meters). Local relief

is mainly 25 feet (8 meters) or less, but some hills and drumlins

rise more than 165 feet (50 meters) above the adjacent

lowlands.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Northwestern Lake Michigan (0403), 46 percent;

Northeastern Lake Michigan-Lake Michigan (0406), 21

percent; Southern Lake Superior-Lake Superior (0402), 20

percent; Northwestern Lake Huron (0407), 10 percent; and

Southwestern Lake Huron-Lake Huron (0408), 3 percent.

Numerous rivers drain this MLRA. The Oconto, Peshtigo, and

Menominee Rivers in Wisconsin and the Escanaba, Ford,

Whitefish, and Manistique Rivers in Michigan empty into Lake

Michigan. The Two Hearted, Sucker, and Tahquamenon Rivers

in Michigan drain into Lake Superior, and the Munuscong,

Carp, and Pine Rivers drain into Lake Huron. The Pine and Pike

Rivers are National Wild and Scenic Rivers, and the Wolf River

is a National Scenic River in the part of this area in Wisconsin.

The Two Hearted River in Michigan is a National Wild and

Scenic River. This MLRA has a significant percentage of

wetlands.

Geology

This area is covered about equally with glacial lake plain,

till, and outwash deposits. The underlying bedrock is

dominantly Silurian, Ordovician, or Cambrian sandstone or

limestone bedrock types that are quarried extensively for
of the United States 293

building materials, steelmaking, and agriculture. Some granitic

rocks and metamorphosed sediments and volcanics underlie the

western edge of this MLRA

Climate

The average annual precipitation in most of this area is 30 to

36 inches (760 to 915 millimeters) but is as low as 28 inches

(710 millimeters) in some areas. About two-thirds of the rainfall

occurs as high-intensity, convective thunderstorms during the

growing season. Snow is common in the winter. The average

annual temperature in most of this area is 39 to 42 degrees F (4

to 6 degrees C), but it can be as high as 44 degrees F (7 degrees

C) in the extreme southern tip of the area, near Menominee,

Wisconsin. The freeze-free period averages about 150 days and

ranges from 120 to 180 days. It is longest in the southern end of

the area and in a narrow belt along Lake Michigan. The Great

Lakes help to moderate the climate of this MLRA.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 39.1%; ground water, 24.7%

Livestock—surface water, 2.3%; ground water, 5.4%

Irrigation—surface water, 2.7%; ground water, 4.1%

Other—surface water, 13.6%; ground water, 8.1%

The total withdrawals average 37 million gallons per day

(140 million liters per day). About 42 percent is from ground

water sources, and 58 percent is from surface water sources.

Many small lakes, a few large lakes, and numerous perennial

streams are sources of good-quality surface water in this area.

Ground water is abundant in the unconsolidated sand and

gravel and lakebed sands in the glacial deposits that cover

almost all of this area. No glacial deposits are used as aquifers

in the far eastern tip of the area. The highest yielding wells are

in the outwash deposits within the drift, but some domestic

water also is pumped from glacial lake sediments and the till

itself. This water is suitable for almost all uses with little or no

treatment. The median level of total dissolved solids is about

200 to 250 parts per million (milligrams per liter). Glacial drift

covers the bedrock aquifers in this area and helps to protect

them from contamination. Agricultural activities, municipal

and industrial waste discharges, and road salts are the primary

sources of contamination.

Three bedrock aquifers, Silurian-Devonian sediments,

Cambrian-Ordovician sandstone and dolomite, and Precambrian

sandstone, occur in the part of this area in Michigan. The

Cambrian-Ordovician sandstone extends south and west into the

part of the area in Wisconsin. The water in these bedrock

aquifers is similar in quality to the water in the glacial aquifers,

but it has slightly more total dissolved solids. It tends to be

fresher where the glacial aquifers are in contact with the

bedrock aquifers and are recharging the water in the bedrock

aquifers. Water from the bedrock aquifers is of good quality and

is suitable for almost all uses.

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, Histosols, and Spodosols. The soils in the area

dominantly have a frigid soil temperature regime, an aquic or

udic soil moisture regime, and mixed or isotic mineralogy.

They are shallow to very deep, excessively drained to very

poorly drained, and sandy to clayey.

Hapludalfs formed in loess over outwash (Nadeau series) on

outwash plains, valley trains, and kames and in till or loess over

till (Emmet and Onaway series) on till plains, moraines, and

drumlins. Glossudalfs formed in till (Pemene, Frechette,

Kennan, Ellwood, Crossett, and Oconto series), in till over

outwash (Perote series), and in sandy deposits over till (Rabe

series) on till plains, moraines, and drumlins. Haplorthods

formed in sandy glacial deposits on outwash plains, valley

trains, and moraines (Kalkaska, Mancelona, Croswell, Au Gres,

and Rubicon series) and in till or loess over till (Trenary,

Tilleda, Charlevoix, Greylock, and Shoepac series), sandy

deposits over till (Menominee and Iosco series), till over

limestone bedrock (Amadon, Longrie, and Reade series), sandy

deposits over igneous bedrock (Ishpeming series), and sandy

eolian deposits (Rousseau and Eastport series) on dunes and

lake plains. Udipsamments formed in sandy eolian deposits on

dunes and lake plains (Shawano series) or in sandy outwash on

outwash plains, valley trains, and moraines (Menahga series).

Haplosaprists (Carbondale, Cathro, Lupton, Markey, and Tawas

series) formed in organic material in depressions on lake plains,

outwash plains, and till plains.

Biological Resources

The soils on uplands in this area support natural stands of

mixed northern hardwoods and pine. Sugar maple, oak, white

ash, elm, yellow birch, white pine, jack pine, red pine, and

American beech are the principal tree species. Lowland areas

support both mixed hardwoods and conifers. Elm, soft maple,

black ash, black spruce, tamarack, and northern white-cedar are

the major species

Some of the major wildlife species in this area are whitetailed deer, black bear, red fox, raccoon, muskrat, cottontail

rabbit, snowshoe hare, squirrel, pheasant, ruffed grouse,

woodcock, mallard, blue-winged teal, and wood duck. Fishing

occurs in Green Bay, Lake Michigan, Lake Huron, streams,

inland lakes, and rivers. The species of fish in the area include

lake trout, rainbow trout, brook trout, walleye pike, largemouth

bass, smallmouth bass, bluegill, black crappie, yellow perch,

and northern pike.
294 Major Land Resource Areas

94C—Michigan Northern Lower

Peninsula Sandy Drift

This area is entirely in the northern part of the Lower

Peninsula of Michigan (fig. 94C-1). It makes up 2,000 square

miles (5,185 square kilometers). The towns of Cheboygan,

Rogers City, and Alpena are in this MLRA. Interstate 75 and

U.S. Highways 23 and 31 pass through the area. Numerous parts

of the Mackinaw State Forest occur in the area.

Physiography

This area is in the Eastern Lake Section of the Central

Lowland Province of the Interior Plains. It is dominated by lake

plains, some of which are till-floored plains. Scattered drumlins,

moraines, and outwash plains are throughout the area. The

terrain includes flat outwash and lake plains and steep slopes in

areas of moraines. Elevation ranges from 580 to 960 feet (175

to 295 meters).

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 3%

Grassland—private, 3%; Federal, 1%

Forest—private, 67%; Federal, 16%

Urban development—private, 3%

Water—private, 2%; Federal, 1%

Other—private, 4%

More than 80 percent of this MLRA is forested, and about

80 percent of the forestland is privately owned. The part of the

MLRA in Michigan is about three-fourths forestland and onefourth cropland. Feed grains and hay are the chief crops. Much

of the grain is fed to dairy cattle and other livestock on the

farms where it is grown. Fruits and other specialty crops also are

important. The rest of the land in farms is about equally divided

between pasture and farm woodlots. Recreation is an important

land use, especially along the major streams and on sites

bordering Green Bay and Lake Michigan.

The major soil resource management concerns are water

erosion, excessive soil wetness, soil fertility, and soil tilth.

Conservation practices on cropland generally include crop

rotations, conservation tillage systems (especially no-till

systems), contour farming, contour stripcropping, and grassed

waterways. A combination of surface and subsurface drainage

systems is needed in most areas of poorly drained soils. 

Figure 94C-1: Location of MLRA 94C in Land Resource Region K.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Northwestern Lake Huron (0407), 92 percent, and Northeastern

Lake Michigan-Lake Michigan (0406), 8 percent. The

Cheboygan, Ocqueoc, and Thunder Bay Rivers are the major

streams in the area. A reach of the Pigeon River is a National

Wild and Scenic River in the south-central part of this MLRA.

Geology

This area is covered with thin to thick glacial deposits.

Bedrock is generally at shallow depths and is evident

throughout the area. It consists of Devonian limestone and

dolomite with interbedded shale, chert, and anhydrite stringers.

Karst features are very common in the area.

Climate

The average annual precipitation is 28 to 34 inches (710 to

865 millimeters). The western one-third of the area is wetter

than the eastern two-thirds. The precipitation occurs as both

rain during the growing season and snow in winter. The average

annual snowfall is 51 to 90 inches (130 to 230 centimeters).

Most of the precipitation comes from the west as air masses

pick up moisture from Lake Michigan. The major storms

generally come from the east or northeast. The average annual

temperature is 42 to 45 degrees F (5 to 7 degrees C). The freezefree period averages about 160 days and ranges from 125 to

190 days.
of the United States 295

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 33.4%; ground water, 8.4%

Livestock—surface water, 17.2%; ground water, 41.0%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 0.0%; ground water, 0.0%

Total withdrawals average 1.2 million gallons per day (4.5

million liters per day). About 49 percent is from ground water

sources, and 51 percent is from surface water sources. This

MLRA is a water-rich area. It is surrounded by Lake Michigan

and Lake Huron. It has many high-quality cold-water streams

and lakes, which generally have a calcium bicarbonate type of

water that can have high levels of dissolved solids.

Ground water is abundant in the unconsolidated sand and

gravel and lakebed sands in the glacial deposits that cover

almost all of this area. The highest yielding wells are in

outwash deposits within the drift, but some domestic water also

is pumped from glacial lake sediments and the till itself. This

water is suitable for almost all uses with little or no treatment. It

is hard, and the median level of total dissolved solids is about

200 to 250 parts per million (milligrams per liter). Agricultural

activities and road salts are the primary sources of potential

contamination in the shallow glacial deposits.

Silurian-Devonian sedimentary rocks underlie the glacial

deposits. They are mostly shale and are not used as sources of

water in this area. Dolomite and anhydrite are in the bedrock,

and karst features are common on the land surface. There is

potential for contamination reaching other bedrock aquifers

through the solution cracks and openings in the limestone or

dolomite bedrock.

Soils

The dominant soils in this MLRA are Spodosols, Alfisols,

Entisols, and Histosols. These soils have a frigid soil

temperature regime, an aquic or udic soil moisture regime, and

dominantly mixed mineralogy. They are very deep, excessively

drained to poorly drained, and sandy. Nearly level to very steep

Haplorthods (Rubicon and Croswell series) and Udipsamments

(Graycalm, Grayling, and Deford series) formed in sandy

glaciofluvial deposits. Nearly level to very steep Glossudalfs

(Onaway, Emmet, Krakow, and Ossineke series) formed in sandy

and loamy glacial till. Very poorly drained Haplosaprists

(Tawas and Lupton series) formed in thick organic deposits or

in organic deposits over sandy glaciofluvial material.

Biological Resources

This area is part of the Northern Lower Michigan Ecosystem

Region and consists mainly of the major forest community

types of northern hardwoods, pines, and coniferous wetlands.

Red pine, white pine, jack pine, white oak, black oak, and red

maple formerly were and currently are the dominant species in

the pine community. Sugar maple, beech, white pine, and

yellow birch formerly were and currently are the dominant

native species of northern hardwoods. Black spruce, tamarack,

northern white-cedar, and white spruce formerly were and

currently are the dominant native species in the coniferous

wetlands. Other important native species include pin cherry,

striped maple, and basswood in the uplands and balsam fir,

eastern hemlock, and speckled alder in the mosaic of wetlands

throughout the area.

Some of the major wildlife species in this area are whitetailed deer, elk, black bear, snowshoe hare, coyote, ruffed

grouse, woodcock, woodland songbirds, ducks, and geese.

Fishing is common in the Great Lakes, numerous inland lakes,

rivers, and streams in the area. The species of fish in the area

include rainbow trout, brown trout, brook trout, Chinook

salmon, coho salmon, northern pike, bass, yellow perch,

bluegill, and sunfish.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 6%

Grassland—private, 8%

Forest—private, 71%

Urban development—private, 3%

Water—private, 6%

Other—private, 6%

About two-thirds of this MLRA is in small, privately owned

holdings, and the other third consists of State forestland. The

forests are used mainly for timber production and recreation.

Dairy and beef operations are very important enterprises in the

area. Forage and feed grain crops for dairy cattle and other

livestock are the principal crops. Wheat, oats, corn, potatoes,

and hay also are grown.

The major soil resource concerns are wind erosion, water

erosion, excessive soil wetness, soil moisture management, and

maintenance of the fertility and productivity of the soils. The

important conservation practices on cropland are systems of

crop residue management (such as no-till or reduced-till

systems), cover crops, wind barriers, stripcropping, and nutrient

management. 
296 Major Land Resource Areas

Figure 94D-1: Location of MLRA 94D in Land Resource Region K.

94D—Northern Highland Sandy Drift

This area (shown in fig. 94D-1) is in Wisconsin (99 percent)

and Michigan (1 percent). It makes up about 2,100 square miles

(5,445 square kilometers). It includes Rhinelander, Eagle River,

Minocqua, Tomahawk, Mercer, and Land O’Lakes, Wisconsin.

Almost all of the Northern Highland-American Legion State

Forest is in the north-central part of the area. Small parts of the

Chequamegon and Nicolet National Forests are just inside the

northwestern and northeastern boundaries of this area,

respectively. Almost all of the Lac du Flambeau Indian

Reservation is in the northwestern part of the area.

Physiography

This area is in the Superior Upland Province of the

Laurentian Upland. Three distinct glacial lobes of the

Laurentian Ice Sheet (Wisconsin Valley, Langlade, and

Ontonagon) have played major roles in shaping the landscape.

The area is characterized by outwash plains (some of which are

pitted or collapsed) and kame moraines intermixed with bogs

and swamps and a few isolated drumlins. It has many lakes. The

streams generally form a dendritic drainage pattern. Elevation

ranges from about 1,500 feet (455 meters) to about 1,850 feet

(565 meters). In much of the area, slopes are nearly level to

gently rolling and local relief is only 10 to 20 feet (3 to 6

meters). Relief ranges from 20 to more than 330 feet (6 to more

than 100 meters) on the moraines.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Wisconsin (0707), 68 percent; Chippewa (0705), 29 percent;

Southern Lake Superior-Lake Superior (0402), 2 percent; and

Western Lake Superior (0401), 1 percent. The Wisconsin,

Tomahawk, and Manitowish Rivers are the major rivers that

drain this MLRA.

Geology

Precambrian-age bedrock underlies most of the glacial

deposits in this MLRA. The bedrock is a complex of folded and

faulted igneous and metamorphic rock that has been modified

by glaciation. The bedrock is covered in most areas by

Pleistocene deposits as much as 330 feet (100 meters) thick.

Most of the Pleistocene sediment was deposited during the last

part of the Wisconsin Glaciation.

Climate

The average annual precipitation in this area is 30 to 35

inches (760 to 890 millimeters). About two-thirds of the rainfall

occurs as convective thunderstorms during the growing season.

Snowfall generally occurs from October through April. The

average annual temperature is 39 to 41 degrees F (4 to 5

degrees C). The freeze-free period averages about 140 days and

ranges from 125 to 155 days.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 64.3%; ground water, 0.0%

Livestock—surface water, 18.0%; ground water, 17.7%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 0.0%; ground water, 0.0%

The total withdrawals average 4 million gallons per day (15

million liters per day). About 18 percent is from ground water

sources, and 82 percent is from surface water sources. Surface

water and ground water are very abundant and readily

available. The sources of surface water are the many lakes and

streams. Water quality is generally good. Most of the lakes and

streams are clear, but those that receive deposits of organic

material from wetland vegetation are tinted brown. The surface

water is used mostly for recreational activities. Extensive

building of cottages and houses along the lakes and streams is a

potential problem for maintaining water quality. Effluent from

sewage disposal facilities pollutes the water and results in the

growth of weeds and algae. This problem is especially severe in

seepage lakes where there is little water exchange.

This MLRA has three types of lakes—spring lakes, seepage

lakes, and drainage lakes. Spring lakes seldom have an inlet,

but they have an outlet with substantial flow. They are fed by

ground water. Seepage lakes generally do not have an inlet or

an outlet but may have an intermittent outlet. The water level is

maintained by the water table or a well sealed lake bottom.

Drainage lakes have an outlet and at least one inlet. Their main

water source is drainage from streams. Spring lakes have a high
of the United States 297

mineral content because they receive the greatest amount of

ground water. Drainage lakes have a lower mineral content than

spring lakes, and seepage lakes have a very low mineral

content. Drainage lakes have the greatest range in reaction.

Water in the spring lakes has reaction similar to that of the

ground water. Seepage lakes commonly are acid, and some of

the drainage lakes are alkaline. About 80 of the lakes are acid,

having a pH of less than 7.0. The rest are neutral or alkaline,

having a pH of 7.0 or higher.

Good-quality ground water comes from glacial deposits. The

total mineral content in this water is commonly less than 150

parts per million (milligrams per liter). The main components of

the water are calcium, magnesium, and bicarbonate ions.

Locally, the dissolved mineral content can be much higher

because of a high content of limestone in some of the glacial

deposits. In some areas minor problems may be caused by

hardness or by high concentrations of iron. Pollution of surface

water is minimal because the area is relatively undeveloped and

there is little municipal or industrial waste. Ground water meets

domestic, agricultural, municipal, and industrial needs in this

MLRA.

Ground water yields from glacial deposits vary. Glacial drift

consisting mainly of sand and gravel yields 100 to more than

1,000 gallons per minute (380 to more than 3,785 liters per

minute). Glacial till yields generally less than 100 gallons per

minute (380 liters per minute). Supplies of ground water may be

inadequate where glacial deposits are thin over crystalline

bedrock. Generally, the fractured crystalline bedrock does not

supply much water, although locally it provides a small amount

(8 gallons, or 30 liters, per minute) for domestic uses.

Soils

The dominant soil orders in this MLRA are Spodosols and

Histosols. The soils have a frigid soil temperature regime, an

aquic or udic soil moisture regime, and mixed mineralogy. The

soils on uplands are very deep, excessively drained to somewhat

poorly drained, and sandy or loamy. The soils on lowlands are

very deep, poorly drained or very poorly drained, and sandy,

loamy, or mucky.

Haplorthods formed in sandy outwash (Croswell, Rubicon,

Vilas, Sayner, and Karlin series) or loamy drift over sandy

outwash (Manitowish, Tipler, Pence, and Padus series) on

outwash plains (some of which are pitted or collapsed) or kame

moraines, in sandy mudflow sediments or till (Keweenaw and

Springstead series) on kame moraines and drumlins, or in

loamy and silty glaciolacustrine sediments (Annalake, Alcona,

and Fence series) on lake plains. Endoaquods formed in sandy

outwash (Kinross and Au Gres series) or loamy drift over sandy

outwash (Wormet and Worcester series) on outwash plains or in

sandy mudflow sediments (Pequaming series) on kame

moraines. Haplosaprists formed in sapric material in swamps

(Markey, Carbondale, and Seelyeville series) and bogs

(Dawson, Loxley, and Greenwood series).

Biological Resources

This area supports conifer-hardwood forest. Sugar maple,

yellow birch, white ash, red oak, aspen, white birch, balsam fir,

white spruce, eastern hemlock, red pine, white pine, and jack

pine are the dominant trees. Poorly drained soils support black

ash, green ash, red maple, black spruce, tamarack, and speckled

alder.

Some of the major wildlife species in this area are whitetailed deer, black bear, eastern gray wolf, ruffed grouse, sharptailed grouse, woodcock, gray squirrel, red squirrel, snowshoe

hare, porcupine, ducks, and geese. Red fox, bobcat, coyote,

muskrat, fisher, mink, otter, raccoon, and beaver are the main

furbearers. The many lakes and forests in this area provide

substantial wildlife habitat. Fishing occurs in the many lakes

and rivers. The species of fish in the area include rainbow trout,

brook trout, walleye pike, largemouth bass, smallmouth bass,

bluegill, black crappie, yellow perch, musky, and northern pike.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 2%

Grassland—private, 2%

Forest—private, 65%; Federal, 5%

Urban development—private, 6%

Water—private, 13%; Federal, 1%

Other—private, 6%

Forests make up most of this area. Timber production and

the production of large amounts of pulp are important land

uses. The paper industry is the largest manufacturer. Sap

collection from sugar maple and syrup production are

important forestry enterprises. Agriculture is a minor land use

because of sandy soils and the short growing season. Some corn

silage, oats, and alfalfa hay are grown. Specialty crops include

snap beans, potatoes, strawberries, and cranberries. Tourism,

recreation, and wildlife management are extremely important.

The vast number of lakes and public forests provide year-round

opportunities for recreation and tourism, especially recreational

hunting, fishing, and hiking.

The major soil resource management concerns are water

erosion, excessive soil wetness, soil fertility, and soil tilth.

Conservation practices on cropland generally include crop

rotations, conservation tillage systems (especially no-till

systems), contour farming, contour stripcropping, and grassed

waterways. A combination of surface and subsurface drainage

systems is needed in most areas of poorly drained soils.

Conservation practices on forestland include forest stand

improvement and forest trails and landings. These practices

reduce the impact of timber management activities on water

quality. Riparian forest buffers help to protect streams and

rivers from timber harvesting activities, improve wildlife

habitat, and protect water quality. 
298 Major Land Resource Areas

Figure 95A-1: Location of MLRA 95A in Land Resource Region K.

95A—Northeastern Wisconsin Drift Plain

This area (shown in fig. 95A-1) is in Wisconsin (88 percent)

and Michigan (12 percent). It makes up about 6,495 square

miles (16,825 square kilometers). It includes the shorelines of

Lake Winnebago and Lake Michigan. The cities of Green Bay,

Appleton, Oshkosh, Fond du Lac, Manitowoc, Sheboygan, and

Whitefish Bay, Wisconsin, and the town of Powers, Michigan,

are in this MLRA. Interstate 43 connects Whitefish Bay,

Sheboygan, and Green Bay, and U.S. Highways 41 and 141 are

important routes north of Green Bay. The Oneida and

Hannahville Indian Reservations are in the parts of this area in

Wisconsin and Michigan, respectively. Small parts of the

Escanaba River and Copper Country State Forests in Michigan

also occur in this area. A number of State parks are along the

shore of Lake Michigan. The Door County area, the peninsula

northeast of Green Bay, is a popular resort area for tourists.

Physiography

This area is in the Eastern Lake Section of the Central

Lowland Province of the Interior Plains. The area is

characterized by nearly level to rolling till plains, lake plains,

and outwash plains mixed with drumlin fields, bedrockcontrolled moraines, lake terraces, flood plains, beaches, dunes,

swamps, and marshes. The drumlins, moraines, and beaches

form low hills and ridges. Lakes and streams are numerous, and

streams generally form a dendritic drainage pattern. Elevation

ranges from 660 to 1,310 feet (200 to 400 meters). Local relief

is mainly 25 feet (8 meters), but some hills rise more than 165

feet (50 meters) above the adjacent lowlands.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Northwestern Lake Michigan (0403), 99 percent, and

Southwestern Lake Michigan (0404), 1 percent. Numerous

small rivers drain this MLRA, and many of the rivers, such as

the Peshtigo, Manitowoc, Menominee, Fox, and Wolf Rivers in

Wisconsin and the Escanaba River in Michigan, empty into

Lake Michigan. Lake Winnebago, east of Oshkosh, is the

largest lake in Wisconsin.

Geology

This area is covered about equally with glacial lake plain,

till, and outwash deposits. Some of the higher areas are

moraines that appear as ridges aligned from north to south.

Most of the bedrock consists of early Paleozoic shale,

limestone, and dolomite rocks. Some granitic rocks and

metamorphosed sediments and volcanics underlie the western

edge of the area. Silurian, Ordovician, and Cambrian sandstone,

dolomite, and shale influence the landscape in some areas.

Bedrock is moderately deep throughout much of the Door

Peninsula.

Climate

The average annual precipitation is 30 to 36 inches (760 to

915 millimeters) in most of this area. It is only 29 inches (735

millimeters) south of and around Green Bay and along Lake

Michigan. About two-thirds of the rainfall occurs as highintensity, convective thunderstorms during the growing season.

Snow is common in winter. The average annual temperature is

41 to 47 degrees F (5 to 8 degrees C). The freeze-free period

averages about 170 days and ranges from 130 to 205 days. It is

longest in the southern part of the area and in a narrow belt

along Lake Michigan. Lake Michigan helps to moderate the

climate of this MLRA.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 6.0%; ground water, 9.2%

Livestock—surface water, 0.5%; ground water, 1.6%

Irrigation—surface water, 0.0%; ground water, 0.2%

Other—surface water, 77.1%; ground water, 5.3%

The total withdrawals average 845 million gallons per day

(3,200 million liters per day). About 16 percent is from ground

water sources, and 84 percent is from surface water sources. The

moderate precipitation generally is adequate for crops and

pasture, but in years of little or no precipitation, lack of

moisture damages crops growing on sandy soils. Lakes and

streams are additional sources of water. Drainage of wet soils on

lowlands is needed for good crop and forage production. The

surface water in this area is generally of excellent quality. Many
of the United States 299

of the streams are trout streams. The Fox River from Lake

Winnebago to the city of Green Bay, along Lake Michigan, is

heavily polluted. Many communities discharge their treated

sewage effluent into this reach, and numerous paper companies

discharge wastewater into the river.

Ground water is plentiful in unconsolidated sand and gravel

deposits in glacial drift, except in areas where the drift is

clayey. All of the ground water in this area primarily contains

calcium, magnesium, and bicarbonate ions. This water is

moderately hard to very hard. It has an average of 220 parts per

million (milligrams per liter) total dissolved solids in the

western part of the area and an average close to 310 parts per

million (milligrams per liter) in the unconsolidated sand and

gravel aquifer in the eastern half of the area, closer to Lake

Michigan. The levels of iron and manganese can exceed the

State drinking water standards and may require treatment for

esthetics.

The western part of this area has a sandstone, dolomite,

dolomite-sandstone, and siltstone aquifer beneath the glacial

deposits. The water in this aquifer is similar in quality to that in

the glacial drift, but the levels of manganese do not exceed State

standards for drinking water. Naturally occurring radium and

fluoride levels do exceed drinking water standards in the Green

Bay area.

Poorer quality ground water is in the Silurian Dolomite

aquifer along the east edge of this area. This is typically the

hardest ground water in the area. The levels of total dissolved

solids commonly exceed the national secondary standard for

drinking water of 500 parts per million (milligrams per liter).

The water also is high in iron, but manganese levels are not so

high as those of the water in the other aquifers.

Soils

The dominant soil orders in this MLRA are Alfisols,

Histosols, and Spodosols. The soils in the area dominantly have

a mesic or frigid soil temperature regime, an aquic or udic soil

moisture regime, and mixed mineralogy. They are very deep,

excessively drained to very poorly drained, and sandy to

clayey. Hapludalfs formed in loess over outwash (Fox and

Spinks series) on outwash plains, valley trains, and kames and

in till or loess over till (Emmet, Kewaunee, Kidder, Manawa,

Ozaukee, and Onaway series) on till plains, moraines, and

drumlins. Glossudalfs (Hortonville and Keenan series) formed

in till on till plains, moraines, and drumlins. Argiudolls

(Hochheim series) formed in loess over till on drumlins and

moraines. Haplorthods formed in sandy glacial deposits on

outwash plains, valley trains, and moraines (Kalkaska series)

and in sandy eolian deposits on dunes, lake plains, and

outwash plains (Rousseau series). Udipsamments (Coloma,

Menahga, and Plainfield series) formed in sandy glacial

deposits on outwash plains, valley trains, and moraines.

Haplosaprists (Carbondale, Cathro, Houghton, Lupton, Markey,

and Tawas series) formed in organic material in depressions on

lake plains, outwash plains, and till plains.

Biological Resources

The soils on uplands in this area support natural stands of

mixed northern hardwoods and pine. Sugar maple, oak, white

ash, elm, yellow birch, white pine, red pine, and American

beech are the principal species. Lowland areas support both

mixed hardwoods and conifers. Elm, soft maple, black ash, and

northern white-cedar are the major species. Lowland brush and

sedge meadows also occur in the low-lying areas.

Some of the major wildlife species in this area are whitetailed deer, red fox, raccoon, muskrat, cottontail, squirrel,

pheasant, ruffed grouse, woodcock, mallard, blue-winged teal,

and wood duck. Fishing occurs in the many lakes and rivers.

The species of fish in the area include rainbow trout, brook

trout, walleye pike, largemouth bass, smallmouth bass, bluegill,

black crappie, yellow perch, musky, and northern pike.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 49%

Grassland—private, 5%

Forest—private, 26%

Urban development—private, 10%

Water—private, 5%

Other—private, 5%

Almost all of this MLRA is in farms. The area is used

dominantly as cropland or pasture. Feed grains and hay are the

chief crops. Much of the grain is fed to dairy cattle and other

livestock on the farms where it is grown. Canning crops, fruits,

and other specialty crops also are important. The rest of the

land in farms is about equally divided between tame pasture and

farm woodlots. About one-tenth of the MLRA is urban land,

and development pressure is high. Recreation is an important

land use, especially along the major streams and on sites

bordering Green Bay and Lake Michigan.

The primary resource concerns are water erosion on

cropland and construction sites, storm-water management,

nutrient management, surface and ground water quality, and

wetland habitat management and restoration. Conservation

practices on cropland generally include systems of crop residue

management, such as mulch-till; cover crops; conservation

cropping systems; and crop rotations. They also include

grassed waterways, filter strips, and nutrient management. 
300 Major Land Resource Areas

Figure 95B-1: Location of MLRA 95B in Land Resource Region K.

95B—Southern Wisconsin and Northern

Illinois Drift Plain

This area (shown in fig. 95B-1) is in Wisconsin (81 percent)

and Illinois (19 percent). It makes up about 10,880 square

miles (28,200 square kilometers). Beloit, Madison, Waukesha,

West Bend, and Beaver Dam, Wisconsin, and Rockford and

McHenry, Illinois, are in this MLRA. Interstates 90 and 94

cross the area. Interstate 43 begins in the southeastern part of

the area, in Wisconsin. Part of the Wisconsin Dells, numerous

other Wisconsin State parks, and many Illinois State parks are

in this area. The MLRA includes the valley of the Wisconsin

River, the eastern Baraboo Hills, and some large lakes and

wetlands.

Physiography

This area is in the Central Lowland Province of the Interior

Plains. Most of the area is in the Eastern Lake Section of the

province, a narrow strip along the western edge of the area is in

the Wisconsin Driftless Section, and the southwestern quarter is

in the Till Plains Section. This area is characterized by gently

sloping ground moraines, lake plains, outwash plains, drumlin

fields, end moraines, flood plains, swamps, and marshes. Most

of the area has belts of morainic hills and ridges and nearly

level outwash terraces. Drumlins (steep-sided, elongated or oval

hills) are prominent features in the north-central part of the area.

The area is dissected by numerous streams and rivers. Elevation

ranges from 660 to 980 feet (200 to 300 meters). Local relief is

mainly 25 feet (8 meters), but the moraines, drumlins, and

bedrock escarpments rise 80 to 330 feet (25 to 100 meters)

above the adjacent lowlands.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Rock (0709), 56 percent; Northwestern Lake Michigan (0403),

21 percent; Upper Illinois (0712), 10 percent; Wisconsin

(0707), 7 percent; and Southwestern Lake Michigan (0404), 6

percent. A short reach of the Wisconsin River is in the western

part of this area. The Fox River in Wisconsin, the Kishwaukee

River in Illinois, and the Pecatonica and Rock Rivers in both

States occur in this MLRA.

Geology

This area is almost entirely covered with glacial drift. The

eastern extent of the “Driftless Area” in southwest Wisconsin

occurs in the western part of the area. Where glacial deposits are

on the surface, the higher areas are moraines that appear as arcshaped ridges representing the retreat of the ice from south to

north. Most of the bedrock in the southern half of this area

consists of Ordovician shale, limestone, and dolomite. A

sequence of Cambrian sandstone, limestone, and shale beds

underlies the glacial deposits in the northern half of the area.

These bedrock units are exposed in the “Driftless Area” along

the southwest margins of the MLRA.

Climate

The average annual precipitation in this area is 30 to 38

inches (760 to 965 millimeters). Most of the rainfall occurs as

high-intensity, convective thunderstorms during the summer.

Snowfall is common in winter. The average annual temperature

is 43 to 48 degrees F (6 to 9 degrees C). The freeze-free period

averages about 170 days and ranges from 150 to 190 days,

decreasing in length from south to north and from the shore of

Lake Michigan inland.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 10.8%; ground water, 9.0%

Livestock—surface water, 0.3%; ground water, 1.1%

Irrigation—surface water, 0.0%; ground water, 1.2%

Other—surface water, 74.2%; ground water, 3.4%

The total withdrawals average 2,280 million gallons per day

(8,630 million liters per day). About 15 percent is from ground

water sources, and 85 percent is from surface water sources. The

moderate precipitation generally is adequate for crops and

pasture, but in years of little or no precipitation, some crops on

coarse textured soils are damaged by a lack of moisture. Many

of the fine textured soils require water management practices

that facilitate tillage and harvesting. Drainage of poorly

drained soils is needed for good production of cultivated crops.
of the United States 301

The many inland lakes and streams typically have good-quality

water. The surface water can be impacted by agricultural and

municipal pollution, but it is generally suitable for most uses.

Ground water is abundant in unconsolidated sand and gravel

deposits throughout the areas covered by glacial drift. All of the

ground water in this MLRA is a calcium-magnesiumbicarbonate type. It is moderately hard to very hard. It has an

average of 220 parts per million (milligrams per liter) total

dissolved solids in the western part of the area and an average

closer to 310 parts per million (milligrams per liter) in the

unconsolidated sand and gravel aquifer in the eastern half of the

area, nearer Lake Michigan. The levels of iron and manganese

can exceed the State drinking water standards and may require

treatment for esthetics.

A sandstone, dolomite, dolomite-sandstone, and siltstone

aquifer is in the “Driftless Area” and beneath the glacial

deposits in the western part of this area. The water in this

aquifer is similar in quality to that in the glacial drift, but the

levels of iron and manganese do not exceed State standards for

drinking water. In the southeast corner of the area, naturally

occurring radium and fluoride levels do exceed drinking water

standards.

Ground water from the St. Peter and Ironton-Galesville

sandstones in Illinois is used extensively. This water is

typically low in total dissolved solids (having a median value

of less than 500 parts per million, or milligrams per liter). It is

very hard, but the levels of iron and manganese do not exceed

the State and Federal drinking water standards. The water in

this aquifer is polluted with volatile organic contaminants and

nitrates from sewage effluent in the Rockford area.

Poorer quality ground water is in the Silurian Dolomite

aquifer along the eastern edge of this area. This is typically the

hardest ground water in the area. The levels of total dissolved

solids commonly exceed the national secondary standard for

drinking water of 500 parts per million (milligrams per liter).

The water also is high in iron, but manganese levels are not so

high as those of the water in the other aquifers.

Soils

The dominant soil orders in this MLRA are Alfisols,

Histosols, and Mollisols. The soils in the area dominantly have

a mesic soil temperature regime, an aquic or udic soil moisture

regime, and mixed mineralogy. They are very deep, generally

well drained to poorly drained, and loamy. They formed

dominantly in a mantle of silty or loamy sediments over loamy

till, in sandy till or mudflow sediments, in a sandy or loamy

mantle over glaciofluvial deposits, in silty or clayey

glaciolacustrine sediments, in mixed alluvium, or in organic

material. Hapludalfs formed in alluvium over outwash (Casco

series) and loess over outwash (Fox series) on outwash plains,

valley trains, and kames and in loess over till (Dodge, Kidder,

McHenry, Miami, and St. Charles series) on till plains,

moraines, and drumlins. Haplosaprists formed in organic

material in depressions on lake plains, outwash plains, and till

plains. Endoaquolls formed in loess over outwash (Drummer

series) and in silty and loamy sediments (Pella series) on till

plains, outwash plains, and stream terraces. Argiudolls formed

in loess over outwash (Elburn series), loess over till (Hochheim,

Plano, and Saybrook series), and till (Griswold series) on till

plains, outwash plains, and stream terraces.

Biological Resources

This area supports hardwoods and prairie vegetation. The

soils on uplands support natural stands of oak, sugar maple, and

hickory and natural prairie vegetation characterized by little

bluestem and big bluestem. Scattered oak and hickory trees

grow on many of the prairies. Lowland areas support sedge and

grass meadows and mixed stands of hardwoods and conifers.

Elm, ash, cottonwood, soft maple, and white cedar are the

major species in the lowland forests.

Some of the major wildlife species in this area are whitetailed deer, red fox, gray fox, raccoon, muskrat, mink,

cottontail, gray squirrel, fox squirrel, pheasant, Wilson’s

snipe, woodcock, ducks, and geese. Fishing occurs in the many

lakes and rivers. The species of fish in the area include rainbow

trout, brook trout, walleye pike, largemouth bass, smallmouth

bass, bluegill, black crappie, yellow perch, musky, and northern

pike.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 55%

Grassland—private, 8%

Forest—private, 14%; Federal, 1%

Urban development—private, 12%

Water—private, 3%

Other—private, 7%

Most of this MLRA is in farms. More than one-half of the

area is cropland. Agricultural uses include the production of

dairy cattle, other livestock, forage, hay, feed grains, sweet

corn, snap beans, canning peas, soybeans, winter wheat, barley,

and fruit. Much of the hay, feed grain, and forage is fed to dairy

cattle and other livestock on the farms where the feed is grown,

but cash-grain farming also is important. Canning crops,

potatoes, fruits, and other specialty crops are important,

especially around urban centers. A significant part of the area is

in small, private woodlots or is used for urban development.

Some of the better farmland is increasingly used for urban

development. Outdoor recreational uses are becoming more

important.

The major soil resource concerns are water erosion on

cropland and construction sites, surface water quality, stormwater management, drainage of wet soils, and protection and

restoration of wetland wildlife habitat. Conservation practices
302

on cropland generally include systems of crop residue

management, such as mulch-till, no-till, and strip-till systems;

cover crops; conservation cropping systems; and crop rotations.

Grassed waterways, grade-stabilization structures, surface and

subsurface drainage systems, and filter strips help to control

concentrated runoff and protect water quality. Nutrient

management and pest management also are important

conservation practices in this area. 
303

Figure L-1: Location of Land Resource Region L.

L—Lake States Fruit, Truck Crop, and

Dairy Region

This region (shown in fig. L-1) is in Michigan (59 percent),

New York (22 percent), Ohio (10 percent), Indiana (8 percent),

and Illinois (1 percent). A very small part is in Pennsylvania.

The region makes up 45,715 square miles (118,460 square

kilometers).

Typically, the land surface is a nearly level to gently sloping

glaciated plain (fig. L-2). The average annual precipitation is

typically 30 to 41 inches (760 to 1,040 millimeters), but it is 61

inches (1,550 millimeters) in the part of the region east of Lake

Erie. The precipitation is fairly evenly distributed throughout

the year. In most of the region, the average annual temperature

is 43 to 49 degrees F (6 to 10 degrees C). The freeze-free period

generally is 145 to 205 days. It is longest in narrow belts

adjacent to the Great Lakes.

The total withdrawals of freshwater in this region average

about 25,540 million gallons per day (96,670 million liters per

day). About 96 percent is from surface water sources, and 4

percent is from ground water sources. The abundant

precipitation and numerous perennial streams provide ample

supplies of good-quality surface water for all uses in the region.

Almost all of the water used in the region is for municipal

supply and industrial purposes.

The soils in this region are dominantly Alfisols, Entisols, or

Spodosols. The dominant suborders are well drained Udalfs,

which are in the southern part of the region, and Boralfs, which

are in the northern part. Aqualfs and Aquepts are the dominant

wet soils throughout the region. The sandy soils are Psamments

or Orthods. Histosols are in bogs and in other low, wet areas.

The soils in the region dominantly have a mesic or frigid soil

temperature regime, an aquic or udic soil moisture regime, and

mixed mineralogy.

About 99 percent of the region is privately owned. The soils

and climate favor agriculture, and the region has a wide variety

of agricultural enterprises. Dairy farming is important, but some

beef cattle also are produced. Canning crops, corn, soft winter

wheat, beans, and sugar beets are among the leading crops.

Fruits, especially sour cherries, are important in a narrow belt

adjacent to the Great Lakes, and wine grapes are grown in the

Finger Lakes area. Much of the cropland near the larger cities is

being subdivided and developed for urban uses.
304 Major Land Resource Areas

The major soil resource concerns are controlling the

pollution resulting from the movement of sediment and

pesticides by water and wind, reducing excess wetness on

cropland, conserving soil moisture in droughty soils,

improving fertility and tilth, and preserving water quality,

wetlands, habitat for fish and wildlife, and prime farmland. 

Figure L-2: Farmland in an area of Land Resource Region L.
of the United States 305

Figure 96-1: Location of MLRA 96 in Land Resource Region L.

96—Western Michigan Fruit Belt

This area is entirely in the western part of the northern

portion of the Lower Peninsula of Michigan (fig. 96-1). It

makes up 2,790 square miles (7,230 square kilometers). The

towns of Manistee, Traverse City, and Petoskey are in this area.

U.S. Highways 31 and 10 pass through the area. Sleeping Bear

Dunes National Lakeshore is just west of Traverse City, and a

small part of the Manistee National Forest is on the southern

edge of the area. The Mackinaw and Pere Marquette State

Forests make up a significant part of this MLRA. Numerous

State parks are throughout the area.

Physiography

This area is in the Eastern Lake Section of the Central

Lowland Province of the Interior Plains. It is in the glaciated

areas of northern Michigan and is dominated by outwash plains

and moraines. Scattered lake plains, till plains, and sand dunes

are throughout the area. The terrain is steep on moraines and

beach ridges and flat on outwash plains and lake plains.

Elevation ranges from 580 to 960 feet (175 to 295 meters).

Local relief is mainly 20 feet (6 meters), but some hills rise

more than 160 feet (50 meters) above the adjacent lowlands.

Much of the area rises sharply from the lakeshore to the

adjoining hilltops.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Northeastern Lake Michigan-Lake Michigan (0406), 93

percent, and Northwestern Lake Huron (0407), 7 percent. The

Manistee River is the longest river in this area. Its trout fishery

is maintained by constant inflow of cool ground water. From

north to south, the Jordan, Boardman, and Betsie Rivers have

been designated as National Wild and Scenic Rivers. The Pine,

Pere, and Marquette Rivers also occur in this MLRA.

Geology

Nearly all of this area has a glacially modified topography.

The bedrock in the area is the Traverse Group and the Dundee

Limestone. These Silurian-Devonian rocks are mostly

limestone and dolomite with some interbedded shale, chert, and

anhydrite stringers. These units are at various depths below the

surface because of the curvature of the Michigan basin. A few

bedrock exposures are on the western shore of the MLRA,

where the outer edges of the basin rise. This MLRA also has

several areas of sand dunes.

Climate

The average annual precipitation in this area is 30 to 36

inches (760 to 915 millimeters). The precipitation occurs as

both rain during the growing season and snow during winter.

The average annual snowfall is 70 to 118 inches (180 to 300

centimeters). Most of the precipitation comes from the west as

prevailing winds pick up moisture from the Great Lakes. The

average annual temperature is 41 to 47 degrees F (5 to 9

degrees C). The freeze-free period averages 155 days and ranges

from 115 to 195 days, increasing in length from north to south

and decreasing in length from the lakeshore inward.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 81,0%; ground water, 13.5%

Livestock—surface water, 0.3%; ground water, 0.7%

Irrigation—surface water, 2.8%; ground water, 1.7%

Other—surface water, 0.0%; ground water, 0.0%

The total withdrawals average 90 million gallons per day

(340 million liters per day). About 16 percent is from ground

water sources, and 84 percent is from surface water sources. In

years of normal precipitation, soil moisture is adequate for

crops, but in years of little or no precipitation, yields are

reduced because of a lack of moisture, especially in the sandy

soils and in areas where bedrock is at a shallow depth. Lake

Michigan and high-quality cold-water streams and lakes in the

area are sources of surface water. The surface water is suitable

for almost all uses with little to no treatment. Streams and lakes

generally have a calcium bicarbonate type of water but can

have high levels of dissolved solids.

Ground water is abundant in areas of deep, sandy and loamy

drift. These deposits consist of outwash, lake sediments, and

till. Wells in the outwash yield the most amount of water, and

wells in the till yield the least. The ground water is of good
306 Major Land Resource Areas

quality. The median level of total dissolved solids is less than

200 parts per million (milligrams per liter). Calcium and

bicarbonate are the principal dissolved substances in the ground

water, and the water is hard. The median concentration of iron is

below the secondary standard for drinking water (300 parts per

billion or micrograms per liter), but some wells exceed the

secondary standard for iron. Problems with nitrate

contamination are related to land use practices. Fertilizer,

manure, and septic systems are the primary sources of nitrates in

the ground water.

A Silurian-Devonian aquifer occurs along the lakeshore in

this area. The quality of the water in this aquifer is very similar

to that of the water in the overlying glacial deposits. This

aquifer is generally below the glacial drift aquifers, so it is little

used in this area. Other sedimentary rocks that underlie the

glacial deposits are mostly shale and are not used as sources of

water.

Soils

The dominant soils in this MLRA are Spodosols, Entisols,

Alfisols, and Histosols. They have a mesic soil temperature

regime, an aquic or udic soil moisture regime, and dominantly

mixed mineralogy. They are very deep and are excessively

drained to very poorly drained. The dominant suborders are

nearly level to very steep Haplorthods (Benona and Grattan

series) and Udipsamments (Coloma and Plainfield series) that

formed in sandy glaciofluvial deposits. Nearly level to very

steep Glossudalfs (Spinks and Remus series) formed in sandy

and loamy glacial till. Very poorly drained Haplosaprists

(Adrian and Houghton series) formed in thick organic deposits

or in organic deposits over sandy glaciofluvial material.

Biological Resources

This area is part of the Northern Lower Michigan Ecosystem

Region. It consists mainly of two major forest community

types—the White Pine Community and the Northern

Hardwoods. Red pine, jack pine, white pine, white oak, black

oak, and red maple formerly were and currently are the

dominant species in the White Pine Community. Sugar maple,

beech, white pine, and yellow birch formerly were and currently

are the dominant native species in the Northern Hardwoods.

Other important native species include pin cherry, striped

maple, and basswood in the uplands and balsam fir, eastern

hemlock, speckled alder, and black spruce in the mosaic of

wetlands throughout the area.

Some of the major wildlife species in this area are whitetailed deer, elk, black bear, snowshoe hare, coyote, ruffed

grouse, woodcock, woodland songbirds, ducks, and geese. The

species of fish in the numerous lakes, rivers, and streams in the

area include rainbow trout, brown trout, brook trout, Chinook

and coho salmon, northern pike, bass, yellow perch, bluegill,

and sunfish.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 11%

Grassland—private, 11%

Forest—private, 54%; Federal, 3%

Urban development—private, 10%

Water—private, 7%; Federal, 1%

Other—private, 3%

About two-thirds of this area is in small, privately owned

holdings, and one-third consists mostly of State forests. The

forests are used mainly for timber production and recreation.

The growth of orchard crops and other crops and dairy and beef

operations are important enterprises in the area. Forage and feed

grains for dairy and other livestock are the principal crops.

Asparagus, wheat, oats, corn, and hay are commonly grown in

the area. Orchard products include sweet and tart cherries,

apples, plums, and peaches.

The major soil resource concerns are wind erosion, water

erosion, wetness, soil moisture management, and maintenance

of the fertility and productivity of the soils. Conservation

practices on cropland generally include crop residue

management systems, such as no-till or reduced-till, that leave

crop residue on the surface. 

97—Southwestern Michigan Fruit and

Truck Crop Belt

This area wraps around the southern end of Lake Michigan

(fig. 97-1). It is in Michigan (76 percent), Illinois (13 percent),

and Indiana (11 percent). It makes up about 3,085 square miles

(7,995 square kilometers). Gary and Michigan City, Indiana,

and most of Chicago, Illinois, are in this MLRA. Interstates 55,

57, 80, 88, 90, and 94 intersect in or near Chicago. Interstate

65 crosses the Indiana Toll Road (Interstates 80 and 90) and

ends in Gary, Indiana, in this area. Interstate 96 crosses the

northern tip of the area, in Grand Rapids, Michigan. A number

of forest preserves are in the urban area around Chicago. The

Indiana Dunes National Lakeshore is in the southern part of the

area.

Physiography

This area is in the Eastern Lake Section of the Central

Lowland Province of the Interior Plains. It consists of a nearly

level glacial drift plain and scattered areas of gently rolling to

strongly rolling hills (moraines). Elevation generally is about

660 feet (200 meters) but is 1,000 feet (305 meters) on some

hills. Local relief is only 5 to 15 feet (2 to 5 meters) in most

areas but is 80 to 160 feet (25 to 50 meters) in the rolling areas.
of the United States 307

Public supply—surface water, 5.8%; ground water, 2.1%

Livestock—surface water, 0.0%; ground water, 0.0%

Irrigation—surface water, 0.2%; ground water, 0.1%

Other—surface water, 89.9%; ground water, 1.9%

The total withdrawals average 7,790 million gallons per day

(29,485 million liters per day). This MLRA ranks seventh

among all of the MLRAs in amount of water used. About 4

percent is from ground water sources, and 96 percent is from

surface water sources. In years of normal precipitation, soil

moisture is adequate for crops, but in years of little or no

precipitation, yields are reduced by a lack of moisture. Most of

the fine textured soils require artificial drainage to ensure that

tillage is not delayed in spring and fall. Wet areas must be

drained before crops can grow well. The many small lakes in

this area are used extensively for boating, fishing, and other

forms of recreation. Lake Michigan is the source of municipal

and industrial water for the Chicago area. The surface water is

suitable for almost all uses, but it is very hard and requires some

treatment.

The glacial deposits in this area yield some ground water for

domestic, municipal, and industrial uses. The highest yielding

wells in the area are in the outwash deposits within the drift, but

some domestic water also is pumped from glacial lake

sediments and from the till itself. This water is suitable for

almost all uses with little to no treatment. The median level of

total dissolved solids is 200 parts per million (milligrams per

liter). The glacial drift covering the bedrock aquifers in this

area helps to protect the aquifers from surface contamination.

Agricultural activities, municipal and industrial waste

discharges, road salts, brine disposal from oil well exploration

and production, and pumping-induced movement of deeper,

more saline water into the aquifers are the primary sources of

contamination.

Two bedrock aquifers occur in this area. One is the shallow

dolomite in northeastern Illinois, and the other is the Marshall

Formation (sandstone) in the northeastern part of the MLRA.

The water quality in the Marshall aquifer is similar to that in

the glacial aquifers. Water in the shallow dolomite contains 400

to 1,200 parts per million (milligrams per liter) total dissolved

solids, which can exceed the recommended level of 1,000 parts

per million (milligrams per liter) for drinking water. The median

iron concentration is 610 parts per billion (milligrams per liter),

which exceeds the national secondary standard, an esthetics

standard, for drinking water of 300 parts per billion (milligrams

per liter). The ground water from the shallow dolomite is very

hard and requires treatment before it is used.

Soils

The dominant soils in this MLRA are Spodosols, Entisols,

Alfisols, and Histosols. They have a mesic soil temperature

regime, an aquic or udic soil moisture regime, and dominantly

mixed mineralogy. They are very deep and are excessively

Figure 97-1: Location of MLRA 97 in Land Resource Region L.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Southeastern Lake Michigan (0405), 71 percent; Southwestern

Lake Michigan (0404), 15 percent; and Upper Illinois (0712),

14 percent. Tributaries to the Grand River and the Kalamazoo

National Wild and Scenic River are in the northern part of the

area. Another Michigan river that drains into Lake Michigan in

this area is the St. Joseph River. The Des Plaines River drains

much of Chicago. It becomes the Illinois River just southwest

of this area.

Geology

The surface of this area is covered mainly with deposits of

glacial drift. Most of the drift consists of till, but some deposits

of unconsolidated sand and gravel outwash are in the area.

Some lake sediments are near the shoreline of Lake Michigan.

The bedrock beneath the glacial deposits consists primarily of

limestone and dolomite in the parts of this area in Illinois and

Indiana and sandstone and shale in the part of the area in

Michigan. Abandoned limestone and dolomite quarries in the

Chicago area are now used to store urban runoff during storms.

Climate

The average annual precipitation in this area is 35 to 40

inches (890 to 1,015 millimeters). The precipitation occurs as

both rain during the growing season and snow during winter.

The average annual snowfall is 70 to 118 inches (180 to 300

centimeters). Most of the precipitation comes from the west as

prevailing winds pick up moisture from the Great Lakes. The

average annual temperature is 47 to 52 degrees F (8 to 11

degrees C). The freeze-free period averages 200 days and ranges

from 175 to 225 days, increasing in length from north to south

and decreasing in length from the lakeshore inward.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:
308 Major Land Resource Areas

drained to very poorly drained. The dominant suborders are

nearly level to very steep Haplorthods (Benona and Grattan

series) and Udipsamments (Coloma and Plainfield series) that

formed in sandy glaciofluvial deposits. Nearly level to very

steep Glossudalfs (Spinks and Remus series) formed in sandy

and loamy glacial till. Very poorly drained Haplosaprists

(Adrian and Houghton series) formed in thick organic

deposits or in organic deposits over sandy glaciofluvial

material.

Biological Resources

This area supports broadleaf deciduous forest vegetation.

Bitternut hickory, shagbark hickory, white oak, red oak, black

oak, American beech, and sugar maple are the dominant tree

species. White ash, red maple, quaking aspen, and black cherry

are extensive on wet sites.

Some of the major wildlife species in this area are whitetailed deer, red fox, opossum, muskrat, mink, cottontail,

woodchuck, tree squirrel, marsh hawk, wild turkey, pheasant,

ruffed grouse, woodcock, kingfisher, quail, cardinal, heron,

crane, Canada goose, snow goose, diving duck, and dabbling

duck. The species of fish in the area include sunfish, perch,

bass, trout, northern pike, walleye, bullhead, sucker, carp,

steelhead, and salmon.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 34%

Grassland—private, 6%

Forest—private, 21%; Federal, 1%

Urban development—private, 29%

Water—private, 2%

Other—private, 7%

More than three-fifths of this MLRA is in farms. Slightly

more than half of the acreage in farms is cropland. Fruits,

especially peaches and grapes, are grown extensively near the

shore of Lake Michigan. Many other fruits and vegetables also

are grown. Forage and feed grains for dairy cattle and other

livestock are important crops. Some areas are used as permanent

pasture, but most of the farmland that is not cultivated is in

woodlots. A large part of the area that is not in farms is in State

forests and parks. Nearly 30 percent of the MLRA is used for

urban development.

The major soil resource concerns are wind erosion, water

erosion, wetness, soil moisture management, and maintenance

of the fertility and productivity of the soils. Conservation

practices on cropland generally include crop residue

management systems, such as no-till or reduced-till, that leave

crop residue on the surface. 

98—Southern Michigan and Northern

Indiana Drift Plain

This area (shown in fig. 98-1) is in Michigan (82 percent),

Indiana (16 percent), and Illinois (2 percent). It makes up about

18,930 square miles (49,050 square kilometers). Interstate 69

connects the towns of Flint and Lansing, Michigan, in this area.

Interstates 94 and 96 cross the center of the area. Interstate 94

connects the towns of Kalamazoo, Battle Creek, and Jackson,

Michigan. Interstate 96 connects Grand Rapids, Lansing, and

Detroit, Michigan. Interstates 80 and 90 become the Indiana

Toll Road across the southern part of the area. The toll road

connects South Bend, Mishawaka, and Elkhart, Indiana. The

Manistee National Forest, the Pere Marquette State Forest, and

a small part of the Au Sable State Forest are in the northwestern

portion of the area. The Isabella Indian Reservation is in the

northern part of the area.

Physiography

This area is in the Eastern Lake Section of the Central

Lowland Province of the Interior Plains. It is a broad glaciated

plain that is deeply mantled by till and outwash. Much of the

area is nearly level to gently rolling. Elevation generally ranges

from 570 to 1,100 feet (175 to 335 meters) but is more than

1,200 feet (365 meters) on some hills. Local relief is generally

less than 15 feet (5 meters). It is 80 to 165 feet (25 to 50 meters)

or more, however, in belts of hills (glacial moraines), which

have stronger slopes.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Southeastern Lake Michigan (0405), 49 percent; Southwestern

Lake Huron-Lake Huron (0408), 18 percent; Northeastern Lake

Michigan-Lake Michigan (0406), 16 percent; Upper Illinois

(0712), 10 percent; St. Clair-Detroit (0409), 4 percent; and

Wabash (0512), 3 percent. The Flat, White, Rogue, and Pere

Marquette Rivers are National Wild and Scenic Rivers in the

Figure 98-1: Location of MLRA 98 in Land Resource Region L.
of the United States 309

northwestern part of the MLRA. Most of the rivers in this area

are short because of their proximity to the Great Lakes east and

west of the area.

Geology

The surface of this area is covered with glacial drift deposits

that are 100 to 500 feet (30 to 150 meters) thick in most areas.

In a few areas in the central part of the MLRA, the deposits are

less than 10 feet (3 meters) thick. At the northern edge of the

area, the drift is more than 600 feet (185 meters) thick. Most of

the drift consists of till, but there are significant deposits of

unconsolidated sand and gravel outwash throughout the area.

Some lake sediments are in the northwest corner of the area,

near the shoreline of Lake Michigan. The bedrock beneath the

glacial deposits in this area is deformed in the shape of a basin.

The center of this basin is in the north-central part of the area.

Jurassic-age shale (red beds) and Pennsylvanian-age sandstone

are in the center of the basin, and Mississippian-age sandstone

and shale beds form the outer rings of the basin.

Climate

The average annual precipitation in most of this area is 29 to

40 inches (735 to 1,015 millimeters). It is lowest in the

northeastern part of the area. The precipitation is fairly evenly

distributed throughout the year, but the amount is slightly

higher late in spring and early in summer. Rainfall occurs as

high-intensity, convective thunderstorms in summer. Snowfall

is common in winter. The average annual temperature is 44 to

50 degrees F (7 to 10 degrees C). Because of the prevailing west

winds crossing Lake Michigan, winters are milder and summers

are cooler than is typical in this part of the continent. The

freeze-free period averages 175 days and ranges from 145 to

200 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 10.3%; ground water, 4.7%

Livestock—surface water, 0.2%; ground water, 0.4%

Irrigation—surface water, 2.8%; ground water, 2.4%

Other—surface water, 72.5%; ground water, 6.7%

The total withdrawals average 3,455 million gallons per day

(13,075 million liters per day). About 14 percent is from ground

water sources, and 86 percent is from surface water sources. In

much of the area, the moderate precipitation is adequate for

crops, but conserving moisture in the coarse textured soils is a

major management concern. Many small and medium-size

lakes and many perennial streams are sources of good-quality

surface water. The lakes are used extensively for recreation.

Municipalities, public-water suppliers, and industry in the

western part of the area obtain surface water from Lake

Michigan. The surface water in this area is very hard and

requires softening prior to most uses.

Ground water is abundant in the deep glacial drift. The

highest yielding wells are in the outwash deposits within the

drift, but some domestic water also is pumped from glacial lake

sediments and from the till itself. This water is suitable for

almost all uses with little to no treatment. The median level of

total dissolved solids is 200 parts per million (milligrams per

liter). The glacial drift covering the bedrock aquifers in this

area helps to protect the aquifers from contamination.

Agricultural activities, municipal and industrial waste

discharges, road salts, brine disposal from oil well exploration

and production, and pumping-induced movement of deeper,

more saline water into the aquifers are the primary sources of

contamination.

Two bedrock aquifers, the Saginaw and Marshall

Formations, occur in this area. The Saginaw Formation is a

sandstone unit with some interbedded shale. The Marshall

Formation is sandstone. Both aquifers are Mississippian in age.

The water quality in the Marshall aquifer is similar to that in the

glacial aquifers. Water in the Saginaw Formation contains

about 350 parts per million (milligrams per liter) total dissolved

solids and commonly contains levels of iron that exceed the

national secondary standard, an esthetics standard, for drinking

water of 300 parts per billion (micrograms per liter). The

Saginaw ground water is the hardest water in all of the aquifers

in Michigan, and it requires treatment prior to use. The water in

these bedrock aquifers tends to be fresher where the glacial

aquifers are in contact with them and they are being recharged

by the water in the glacial aquifers.

Soils

The dominant soil orders in this MLRA are Alfisols,

Histosols, and Mollisols. The soils in the area dominantly have

a mesic soil temperature regime, an aquic or udic soil moisture

regime, and mixed mineralogy. They are very deep, well

drained to very poorly drained, and loamy or sandy. Hapludalfs

formed in outwash or glacial drift over outwash on outwash

plains, kames, terraces, and deltas (Boyer, Oshtemo, and Spinks

series) or in till (Hillsdale and Riddles series) or loess over till

(Miami series) on till plains and moraines. Glossudalfs (Capac

and Marlette series) and Endoaqualfs (Conover series) formed

in till on till plains and moraines. Haplosaprists (Houghton

series) formed in organic deposits in depressions on lake plains,
310 Major Land Resource Areas

till plains, and outwash plains. Argiaquolls (Sebewa series) and

Endoaquolls (Gilford and Maumee series) formed in outwash in

depressions on outwash plains, flood plains, and lake plains.

Argiaquolls (Brookston series) also formed in silty material

over till in depressions on till plains and moraines.

Biological Resources

This area supports broadleaf deciduous forests. Bitternut

hickory, shagbark hickory, white oak, red oak, black oak, sugar

maple, and beech are the dominant tree species. Red maple,

white oak, and American basswood are extensive on the wetter

soils.

Some of the major wildlife species in this area are whitetailed deer, coyote, red fox, gray fox, beaver, river otter,

snowshoe hare, cottontail, fox squirrel, gray squirrel, black

squirrel, red squirrel, mink, pheasant, sharp-tailed grouse,

prairie chicken, ruffed grouse, and wood duck. The species of

fish in the area include bass, sunfish, northern pike, rainbow

trout, walleye, brown trout, coho salmon, Chinook salmon, and

brook trout.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 47%

Grassland—private, 7%

Forest—private, 23%; Federal, 2%

Urban development—private, 12%

Water—private, 2%

Other—private, 7%

More than three-fourths of this MLRA is in farms. The rest is

used mainly for urban development. Much of the farmland is in

small woodlots. A small acreage is in State forests and parks.

Nearly one-half of the area is cropland. Corn, other feed grains,

and hay for dairy cattle and other livestock are the major crops.

Soft winter wheat and dry beans are important cash crops, and

fruits and vegetables are grown in many areas where the soils

and markets are favorable. Less than one-tenth of the area is

permanent pasture.

The major soil resource concerns are controlling the

pollution resulting from the movement of sediment and

pesticides by water and wind, reducing excess soil wetness on

cropland, conserving soil moisture in droughty soils, improving

the fertility and tilth of the soils, and preserving water quality,

wetlands, and prime farmland. Conservation practices on

cropland generally include grassed waterways, conservation

borders and field borders, pest and nutrient management,

windbreaks, field stripcropping, crop residue management,

cover crops, conservation tillage, diversions, grade-stabilization

structures, and waste management. 

99—Erie-Huron Lake Plain

This area (shown in fig. 99-1) is in Michigan (58 percent),

Ohio (40 percent), and Indiana (2 percent). It makes up about

10,950 square miles (28,370 square kilometers). The cities and

towns of Detroit, Saginaw, Midland, Port Huron, and Bay City,

Michigan, and Toledo, Maumee, Bowling Green, Port Clinton,

and Sandusky, Ohio, are in this MLRA. Interstates 80 and 90

become the Ohio Turnpike, a toll road, across the southern part

of the area. Interstate 75 connects the towns of Bowling Green

and Toledo, Ohio, with Detroit, Michigan. Interstate 75 leaves

the area northwest of Detroit but enters the northern part of the

area and passes through Saginaw, Midland, and Bay City,

Michigan. Interstates 94 and 69 meet in Port Huron, Michigan,

north of the center of the area. A number of State parks are

along the shores of Lake Erie and Lake Huron. The Au Sable

State Forest is in the northwestern part of this MLRA, in

Michigan, and the Maumee State Forest is in the southern part,

in Ohio.

Physiography

This area is in the Eastern Lake Section of the Central

Lowland Province of the Interior Plains. It is a nearly level

glacial lake plain with a few scattered ridges of sandy soils that

represent past shorelines and moraines. Elevation is about 660

feet (200 meters), increasing gradually from the lakeshore

inland. Local relief generally is only about 6 feet (2 meters), but

some beach ridges and low moraines rise almost 30 feet (9

meters) above the general level of the landscape. The part of

this MLRA in Ohio was probably a swamp prior to the

introduction of drainage by early settlers. Remnant marshes are

near the Lake Erie shore.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Western Lake Erie (0410), 49 percent; Southwestern Lake

Huron-Lake Huron (0408), 33 percent; St. Clair-Detroit (0409),

Figure 99-1: Location of MLRA 99 in Land Resource Region L.
of the United States 311

municipal drinking water needs in the area. It is typically a

calcium bicarbonate type of water in which the level of total

dissolved solids is about 200 to 300 parts per million

(milligrams per liter). In areas where the level of total dissolved

solids is higher, the water type changes to sodium sulfate. All of

the ground water is hard or very hard. Sources include

unconsolidated sand and gravel deposits in the glacial till and

glacial outwash in the southeastern part of the area. Some water

also can be obtained from sands in the lake deposits. Around

Saginaw, Michigan, and northwest Ohio, ground water is

available in bedrock units, from the Saginaw Formation and

from older carbonate rocks, respectively.

Soils

The dominant soils in this MLRA are Alfisols, Inceptisols,

Mollisols, and Spodosols. The soils in the area dominantly

have a mesic soil temperature regime, an aquic soil moisture

regime, and mixed or illitic mineralogy. They are very deep,

generally somewhat poorly drained to very poorly drained, and

loamy or clayey. Epiaqualfs (Blount, Hoytville, Nappanee, and

Shebeon series) and Glossudalfs (Capac series) formed in till

(some of which is dense) on till plains, moraines, and lake

plains. Epiaquepts formed in loamy till on till plains and

moraines (Kilmanagh series) and in lacustrine deposits on lake

plains (Lenawee and Paulding series). Endoaquepts formed in

lacustrine deposits on lake plains (Latty and Toledo series) and

in loamy till on moraines (Parkhill series). Endoaquolls formed

in outwash deposits on outwash plains and lake plains and in

drainageways (Granby series) and in loamy till on till plains and

moraines (Tappan series). Endoaquods (Pipestone series)

formed in outwash deposits on outwash plains, lake plains, and

beach ridges. Epiaquods (Wixom series) formed in sandy

sediments over till or lacustrine deposits on till plains, outwash

plains, and lake plains.

Biological Resources

This area supports broadleaf deciduous forests. Bitternut

hickory, shagbark hickory, white oak, red oak, and black oak

are the dominant tree species. Red maple, white ash, American

basswood, and quaking aspen are dominant on the wetter soils.

Some of the major wildlife species in this area are raccoon,

rabbit, squirrel, pheasant, and quail.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 59%

Grassland—private, 3%

Forest—private, 12%

Urban development—private, 17%

Water—private, 4%

Other—private, 5%

17 percent; and Southeastern Lake Michigan (0405), 1 percent.

The Maumee and Sandusky Rivers are National Wild and

Scenic Rivers in the part of this area in Ohio. The Saginaw,

Clinton, and Huron Rivers empty into the Great Lakes in the

part of the area in Michigan.

Geology

The southern half of this area is covered with glacial

deposits of till, lake sediments, and outwash from the

Wisconsin and older glacial periods. The area also has some

low moraines. Mississippian- to Silurian-age shale, limestone,

and dolomite rocks are at the surface in the northern half of this

area, along the shores of Lake Erie and Lake Huron in

Michigan. These rocks underlie the glacial deposits in the

southern half of the area.

Climate

The average annual precipitation is 30 to 36 inches (760 to

915 millimeters) in the southern half of this area and about 27

inches (685 millimeters) in the northern half. Most of the

rainfall occurs as high-intensity, convective thunderstorms in

summer. Snowfall is common in winter. The average annual

temperature is 44 to 51 degrees F (7 to 10 degrees C). The

average freeze-free period is 190 days and ranges from 155 to

220 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 5.0%; ground water, 0.5%

Livestock—surface water, 0.1%; ground water, 0.0%

Irrigation—surface water, 0.2%; ground water, 0.1%

Other—surface water, 92.8%; ground water, 1.2%

The total withdrawals average 10,050 million gallons per

day (38,040 million liters per day). This MLRA ranks fifth

among all of the MLRAs in amount of water used. About 2

percent is from ground water sources, and 98 percent is from

surface water sources. In most years the moderate precipitation

provides enough water for crops. Many of the soils require

artificial drainage before they can be used for crops, and even

the better drained soils require some drainage to ensure that

tillage is not delayed in spring and fall. The Great Lakes supply

water for large cities, are major transportation arteries, and are

used for recreation. The surface water is abundant in this area

and is of good quality. It is suitable for almost all uses with

little treatment, except in reaches downstream from municipal

or industrial waste discharge points.

The abundant ground water in this area is not used

extensively because of the availability of good-quality surface

water. The ground water meets most domestic and some
312 Major Land Resource Areas

Figure 101-1: Location of MLRA 101 in Land Resource Region L.

Nearly three-fourths of this MLRA is in farms. About threefifths of the area is cropland. The rest of the farmland is mostly

in small farm woodlots, but some of the farmland is used for

permanent pasture or other purposes. Cash crops are important.

Corn, winter wheat, soybeans, and hay are the major crops.

Sugar beets and canning crops also are important. Some fruit

and truck crops are grown on the coarse textured soils. Dairying

is an important enterprise on some farms near the larger cities.

Almost one-fifth of the area is used for urban development.

The major resource concerns are seasonal wetness;

maintenance of the content of organic matter and productivity

of the soils; water erosion and wind erosion; excessive

sediment, nutrients, and pesticides in surface water; nutrients

and pesticides in ground water; and the loss of habitat for fish

and wildlife. The conservation practices that are important in

addressing these resource concerns generally include surface

and subsurface drainage systems, conservation crop rotations,

crop residue management, filter strips, riparian forest buffers,

nutrient management, pest management, protection of

streambanks and shorelines, agrichemical containment

facilities, and management of upland and wetland wildlife

habitat. 

101—Ontario-Erie Plain and Finger

Lakes Region

This area (shown in fig. 101-1) is in New York (99 percent)

and Pennsylvania (1 percent). It makes up about 9,960 square

miles (25,815 square kilometers). The cities of Buffalo,

Rochester, Syracuse, and Utica, New York, are connected by

Interstate 90, which crosses the entire area. The town of

Gloversville, New York, is in the eastern end of the area, and

Watertown, New York, is in the northern part. Interstate 81

connects Syracuse and Watertown. This MLRA extends as far

south as Ithaca, New York, and includes the Finger Lakes

Region. Numerous State parks occur in the Finger Lakes

Region and along the shores of Lake Erie and Lake Ontario.

The western part of the Fort Drum Military Reservation is in the

far northeast corner of this MLRA. The Tuscarora and

Cattaraugus Indian Reservations also are in this MLRA. The

New York State (Erie) Canal crosses the northwestern part of

the area.

Physiography

Most of this area is in the Eastern Lake Section of the

Central Lowland Province of the Interior Plains. The southeast

quarter of the area is in the Southern New York Section of the

Appalachian Plateaus Province of the Appalachian Highlands,

and the northeast corner is in the Mohawk Section of the same

province and division. Most of the MLRA is a nearly level to

rolling plain. Low remnant beach ridges are commonly

interspersed with a relatively level lake plain in the northern

part of the area. Drumlins (long, narrow, steep-sided, cigarshaped hills) are prominent in an east-west belt in the center of

the area. The Finger Lakes Region consists of a gently sloping

to rolling till plain. Elevation is 330 to 1,310 feet (100 to 400

meters), increasing gradually from the shores of Lake Ontario

and Lake Oneida to the Allegheny Plateau, the southern border

of the area. Local relief is mostly 10 feet (3 meters), but the

larger drumlins and many valley sides rise 80 to 330 feet (25 to

100 meters) above the adjacent lowlands or valley floors.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Southeastern Lake Ontario (0414), 45 percent; Upper Hudson

(0202), 20 percent; Southwestern Lake Ontario (0413), 18

percent; Eastern Lake Erie-Lake Erie (0412), 12 percent; and

Susquehanna (0205), 5 percent. Many rivers cross this area and

discharge into Lake Erie and Lake Ontario, which border the

area on the north. Most of the streams in this area flow north,

but the Mohawk River flows east.

Geology

The bedrock underlying this area consists of alternating

beds of limestone, dolomite, sandstone, and shale of

Ordovician to Devonian age. Most of the surface of the area is

covered with glacial till or lake sediments. The texture of the

lake sediments is silt, loam, or sand. Ancient beaches, formed at

different lake levels, form ridges along the shoreline of Lake

Erie and Lake Ontario. Stratified drift (eskers and kames) and

glacial outwash deposits are in many of the valleys. A large

drumlin field occurs in the Finger Lakes Region.
of the United States 313

Climate

The average annual precipitation in most of this area is 29 to

45 inches (735 to 1,145 millimeters). It is as high as 61 inches

(1,550 millimeters) in the extreme eastern end of the area, near

the Adirondack Mountains, and in the extreme western end,

along the shore of Lake Erie, and is less than 30 inches (760

millimeters) in a few areas near the center of the MLRA. The

precipitation is evenly distributed throughout the year. Most of

the rainfall occurs as high-intensity, convective thunderstorms

in summer. Heavy snowfall is common in winter. The average

annual temperature is 42 to 50 degrees F (5 to 10 degrees C).

The freeze-free period averages 175 days and ranges from 145

to 205 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 21.8%; ground water, 0.5%

Livestock—surface water, 0.1%; ground water, 0.1%

Irrigation—surface water, 0.2%; ground water, 0.0%

Other—surface water, 75.1%; ground water, 2.2%

The total withdrawals average 4,155 million gallons per day

(15,725 million liters per day). About 3 percent is from ground

water sources, and 97 percent is from surface water sources. In

most years the precipitation is adequate for crops, except for

those on the coarse textured soils. Irrigation water for highvalue fruit and vegetable crops is obtained from wells or from

the Great Lakes. The wetter soils must be drained before they

can be used for crops, and even the better drained soils benefit

from drainage. Many of the larger cities in the area obtain water

from the Great Lakes. The Great Lakes also provide

transportation and are used extensively for recreation. The

Finger Lakes also are used for recreation. The surface water in

the area is suitable for almost all uses with little to no

treatment.

Ground water is not used to any extent in this area because

of the abundance of surface water. The ground water also is

abundant and meets domestic, industrial, and municipal needs

in parts of the area. All of the aquifers are fairly shallow and are

subject to contamination from agriculture and urban and

industrial wastes. A sandstone aquifer is used in the

northeastern part of the area. The sandstone has very hard water,

but the median value of total dissolved solids is only about 300

parts per million (milligrams per liter). The sandstone also has

the highest levels of chloride of all the aquifers in this area. The

median value of 100 parts per million (milligrams per liter),

however, is well below the drinking water standard of 250 parts

per million (milligrams per liter) for chloride.

A carbonate aquifer occurs all along the southern half of this

area. It has naturally occurring saline zones in which evaporate

deposits occur and the level of total dissolved solids exceeds

1,000 parts per million (milligrams per liter). Typically, water

from this aquifer contains 500 parts per million (milligrams per

liter) total dissolved solids, which is well below the national

standard for drinking water. This aquifer produces the hardest

water in New York and requires treatment prior to use.

Lake sediments and valley fill deposits of glacial outwash

and stratified drift in this area have good-quality ground water.

This water has low levels of total dissolved solids, 200 parts per

million (milligrams per liter), but is very hard and requires

softening prior to use. These shallow aquifers are very

susceptible to contamination from surface activities.

Soils

The dominant soils in this MLRA are Alfisols and

Inceptisols. The dominant suborders are Udalfs and Udepts. The

soils in the area have a mesic soil temperature regime, a udic

soil moisture regime, and mixed mineralogy. They are deep and

are medium textured or moderately fine textured. Well drained

and moderately well drained, undulating to moderately sloping

Hapludalfs formed in glacial till high in content of lime

(Honeoye, Cazenovia, and Hilton series). They also formed in

lacustrine sediments (Schoharie and Galen series). Nearly level

to gently sloping, somewhat poorly drained Endoaqualfs

(Appleton and Niagara series) are extensive in low areas. Poorly

drained and very poorly drained Endoaquepts (Canandaigua

and Lamson series) formed in lacustrine sediments and are

common at the lowest elevations in the northern part of the

area. Hapludalfs that formed in calcareous outwash deposits

(Palmyra and Wampsville series) and in moderately deep till

(Aurora and Lairdsville series) are prominent locally but are of

small extent. Well drained and moderately well drained

Eutrudepts (Hamlin and Teel series) formed in alluvial deposits

along streams.

Biological Resources

This area supports forest vegetation, particularly hardwoods.

The potential forest types are elm-ash-red maple or beechbirch-sugar maple in varying proportions. Other species

associated with these types include basswood, hemlock, white

pine, black cherry, and some species of upland oak. Northern

white-cedar, red maple, black ash, and aspen grow on the wet

soils. Cattails and mosses grow on the organic soils and on

other extremely wet sites.

Some of the major wildlife species in this area are whitetailed deer, cottontail, gray squirrel, pheasant, woodcock, and

ruffed grouse.
314

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 36%

Grassland—private, 10%

Forest—private, 31%; Federal, 1%

Urban development—private, 15%

Water—private, 4%

Other—private, 3%

Most of this area is in farms. About one-third of the acreage

is cropland, which is used mainly for hay, corn, and small grains

associated with dairy operations. Cash crops, including

canning and truck crops, wheat, and dry beans, also are grown.

Orchard crops are important locally, particularly near Lake

Ontario. Vineyards are common near some of the Finger Lakes.

About one-third of the area is forestland, mostly in farm

woodlots. About 15 percent of the area is used for urban

development, which is expanding around the larger cities, such

as Buffalo, Rochester, and Syracuse.

The major soil resource concerns are sheet and rill erosion,

the sedimentation caused by storm-water runoff, maintenance

of the content of organic matter and productivity of the soils,

and management of soil moisture. Conservation practices on

cropland generally include crop residue management;

conservation tillage; winter cover crops; nutrient management,

including manure management; and pesticide management.

Excluding livestock from wetlands and watercourses and

developing rotational grazing systems help to control erosion

and protect water quality. Conservation practices that are

important to community development include critical area

treatment and urban storm-water management. 
315

Figure M-1: Location of Land Resource Region M.

M—Central Feed Grains and Livestock

Region

This region (shown in fig. M-1) is in Iowa (20 percent),

Illinois (18 percent), Missouri (13 percent), Minnesota (11

percent), Indiana (9 percent), Kansas (6 percent), Nebraska

(6 percent), Ohio (6 percent), Wisconsin (4 percent), South

Dakota (4 percent), Oklahoma (2 percent), and Michigan (1

percent). Also, very small parts are in North Dakota and

Kentucky. The region makes up 282,450 square miles (731,905

square kilometers).

Typically, the land surface is a nearly level to gently

sloping, dissected glaciated plain (fig. M-2). The average

annual precipitation is typically 32 to 39 inches (815 to 990

millimeters), but it ranges from 19 to 48 inches (485 to 1,220

millimeters), increasing from north to south. Most of the

precipitation occurs during the growing season. In most of the

region, the average annual temperature is 47 to 53 degrees F

(8 to 12 degrees C), but it ranges from 38 to 62 degrees F (4 to

17 degrees C), increasing from north to south. The freeze-free

period generally is 170 to 210 days. It increases in length from

north to south.

The total withdrawals of freshwater in this region average

about 35,945 million gallons per day (136,050 million liters

per day). This is one of six land resource regions that use more

than 30,000 million gallons per day (113,550 million liters per

day). This region is second only to the Northwestern Wheat and

Range Region (LRR B) in total amount of water used. About 87

percent is from surface water sources, and 13 percent is from

ground water sources. Abundant precipitation and numerous

perennial streams provide ample supplies of good-quality

surface water for all uses in the region. The lower reaches of the

large rivers in the southern part of the region have poor-quality

water primarily because of sediment, nutrients, and pesticides

from agricultural runoff.

The soils in this region are dominantly Alfisols, Entisols,

Inceptisols, or Mollisols. Some Histosols occur on flood plains

and in wetlands. The dominant suborders are Udalfs, Aqualfs,

and Aquolls. The sandy soils are typically Psamments. The soils
316 Major Land Resource Areas

in the region dominantly have a mesic soil temperature regime,

an aquic or udic soil moisture regime, and mixed or smectitic

mineralogy.

About 99 percent of this region is privately owned. The soils

and climate favor agriculture. This region produces most of the

corn, soybeans, and feed grains produced in the U.S. The grains

and hay grown in the region commonly are fed to beef cattle.

Some specialty crops are grown near markets in the

metropolitan areas. Much of the cropland near the larger cities

is being subdivided and developed for urban uses. Small areas

in the parts of this region in southern Indiana and in Illinois are

strip-mined for coal.

The major soil resource concerns are water erosion, wetness,

and maintenance of the content of organic matter and

productivity of the soils. Wind erosion is a hazard in some of

the northern parts of the region where the lighter textured soils

occur. Protecting wildlife habitat and preserving the quality of

surface water and ground water are additional concerns in many

parts of this region. 

Figure M-2: Riparian buffer in an area of Land Resource Region M.
of the United States 317

Figure 102A-1: Location of MLRA 102A in Land Resource Region M.

102A—Rolling Till Prairie

This area (shown in fig. 102A-1) is mostly in Minnesota (58

percent) and South Dakota (42 percent). A small part is in North

Dakota. This MLRA makes up about 16,545 square miles

(42,870 square kilometers). It includes the cities or towns of

Fergus Falls, Marshall, Montevideo, and Morris, Minnesota,

and Brookings, Milbank, and Watertown, South Dakota. The

town of Willmar, Minnesota, is on the southeast boundary of

the area. Interstates 29 and 94 cross parts of the MLRA. The

Pipestone National Monument is in the part of this area in

Minnesota. The eastern edge of the Central Flyway and the

western edge of the Atlantic Flyway are in this MLRA, so

numerous migrating waterfowl occur in the area. The MLRA

has many public wildlife areas.

Physiography

Most of this area is in the Western Lake Section of the

Central Lowland Province of the Interior Plains. The center of

the Prairie Coteau, in northeastern South Dakota, is in the

Dissected Till Plains Section of the same province and division.

This MLRA is an area of nearly level to rolling topography that

has many depressions and ill-defined drainages. “Prairie

pothole” lakes and ponds are common. The steeper slopes

occur on the sides of drainages and on breaks adjacent to some

of the larger tributaries. Elevation generally ranges from 1,000

to 1,350 feet (305 to 410 meters) on lowlands and from 1,350 to

1,650 feet (410 to 505 meters) on uplands. Isolated highs on the

Prairie Coteau, in northeastern South Dakota, are at an

elevation of more than 2,000 feet (610 meters). The Prairie

Coteau is one of the more prominent landforms in North

America. The northern tip of this wedge-shaped highland is in

North Dakota. This high area split the last continental ice sheet

into the Des Moines and James Lobes.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Minnesota (0702), 42 percent; Missouri-Big Sioux (1017), 25

percent; Red (0902), 17 percent; James (1016), 10 percent;

Mississippi Headwaters (0701), 5 percent; and Des Moines

(0710), 1 percent. The headwaters of the Red River of the North

(draining into Hudson Bay) and the Minnesota River (draining

into the Mississippi River) are in this area. The part of the

Minnesota River in the southeast corner of this area is a

National Wild and Scenic River. Some of the major tributaries

to the Red River are the Sand Hill, Poplar, Marsh, Wild Rice,

Buffalo, Otter Tail, Mustinka, and Bois de Sioux Rivers. The

major tributaries to the Minnesota River are the Chippewa,

Pomme de Terre, Whetstone, Lac qui Parle, Yellow Medicine,

and Cottonwood Rivers. The Big Sioux River begins in this

area, near Watertown, South Dakota. Lake Traverse and Big

Stone Lake are on the border between South Dakota and

Minnesota. These lakes are on the continental divide where

streams drain either north to Hudson Bay or south to the Gulf of

Mexico. Lakes, ponds, and marshes are common in the area.

Geology

The dominant landforms in this area are stagnation

moraines, end moraines, glacial outwash plains, terraces, and

flood plains. The MLRA is dominated by till-covered moraines.

The stagnation moraines are gently undulating to steep and

have many depressions and poorly defined drainages. The

steepest slopes are on escarpments adjacent to some of the

larger tributaries. Small outwash areas are adjacent to the

watercourses. The Cretaceous Pierre Shale underlies the till in

most of the area. Precambrian rocks also occur at depth. Granite

is quarried at Milbank, South Dakota, and outcrops of Sioux

Quartzite are common. Layers of silt in the quartzite near

Pipestone, Minnesota, were quarried by Native Americans, and

the stone was carved for pipe bowls.

Climate

The average annual precipitation in this area is 19 to 29

inches (485 to 735 millimeters). Half or more of the

precipitation falls during the growing season. Rainfall typically

occurs as high-intensity, convective thunderstorms during the

summer. Precipitation in winter occurs mostly as snow. The

average annual temperature is 38 to 45 degrees F (4 to 7

degrees C). The freeze-free period averages about 155 days and
318 Major Land Resource Areas

ranges from 140 to 175 days. In the western part of the MLRA,

rainfall is less abundant and is not always adequate for full

maturation of crops.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 2.4%; ground water, 11.7%

Livestock—surface water, 0.4%; ground water, 11.1%

Irrigation—surface water, 34.9%; ground water, 30.2%

Other—surface water, 1.0%; ground water, 8.3%

The total withdrawals average 145 million gallons per day

(550 million liters per day). About 61 percent is from ground

water sources, and 39 percent is from surface water sources.

Precipitation is the principal source of moisture for crops. In

some years it is inadequate for maximum crop production. Small

ponds and shallow wells are the principal sources of water for

livestock. Both surface water and ground water are used for some

irrigation in the area. Many natural glacial lakes are in the

northern part of the area, and many of the larger ones are used for

recreation. The water in the lakes and larger streams is generally

suitable for all uses. The quality of the water in the smaller

streams is generally poor. The water is slightly saline at low flows.

Shallow wells in glacial outwash deposits, primarily sand

and gravel, provide water for livestock, domestic use, and

irrigation in this area. This water is hard but is of good quality.

The median level of total dissolved solids is 350 parts per

million (milligrams per liter). Ground water also is available in

deep wells in the Precambrian bedrock in this area or in the

Dakota Sandstone. These aquifers are seldom utilized in this

area because of an abundance of shallow glacial deposits and

surface water.

Soils

The dominant soil order in this MLRA is Mollisols. The

soils in the area dominantly have a frigid soil temperature

regime, an aquic or udic soil moisture regime, and mixed

mineralogy. They generally are very deep, well drained to very

poorly drained, and loamy. Hapludolls formed in loamy till

(Barnes, Forman, and Hokans series), in loess or silty drift over

till (Kranzburg, Poinsett, and Waubay series), in eolian deposits

(Egeland and Embden series), and in glacial outwash (Arvilla,

Fordville, and Renshaw series) on till plains and moraines.

Calciudolls (Buse and Balaton series) formed in loamy till on

rises and ridges. Argiaquolls (Parnell and Badger series) formed

in loamy till and colluvial and alluvial sediment in swales and

depressions. Argialbolls (Tonka series) and Endoaquolls formed

in colluvial and alluvial sediment in depressions (Quam series)

and in alluvial sediment on flood plains (Lamoure and Rauville

series). Calciaquolls (Marysland and Moritz series) formed in

alluvial sediments on flood plains.

Biological Resources

This area supports true prairie vegetation characterized by

big bluestem, little bluestem, porcupinegrass, and green

needlegrass. Needleandthread and prairie dropseed are

important species on the steeper soils. Prairie cordgrass

commonly grows in wet areas.

Some of the major wildlife species in this area are whitetailed deer, beaver, muskrat, mink, pheasant, gray partridge,

giant Canada goose, mallard, blue-winged teal, wood duck,

northern shoveler, pintail, ruddy duck, widgeon, redhead,

canvasback, chestnut-collared longspur, marbled godwit, and

upland plover. The species of fish in the area include walleye,

northern pike, yellow perch, black crappie, white crappie, white

bass, catfish, black bullhead, bluegill, carp, white sucker,

buffalo, redhorse, and bait minnow.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 66%

Grassland—private, 17%; Federal, 1%

Forest—private, 3%

Urban development—private, 3%

Water—private, 4%

Other—private, 6%

Most of this area is in farms, and about two-thirds is

cropland used for crops grown for sale or for feeding

livestock. The principal crops are corn, soybeans, alfalfa,

spring wheat, and oats. Wooded areas generally occur as

narrow bands along streams and rivers or as shelterbelts around

farmsteads. Recreational hunting and fishing are important

land uses around the many natural lakes in the northern part of

the area.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and

productivity of the soils, soil wetness, and management of soil

moisture. Conservation practices on cropland generally include

systems of crop residue management, especially no-till or other

conservation tillage systems that conserve moisture and

contribute to soil quality. Other practices include terraces,

vegetative wind barriers, grassed waterways, and nutrient

management. 

102B—Till Plains

This area is entirely in South Dakota (fig. 102B-1). It makes

up about 2,215 square miles (5,735 square kilometers). The

towns of Madison, Canton, and Parker are in this MLRA.

Vermillion is on the southern edge of the area, and parts of
of the United States 319

Figure 102B-1: Location of MLRA 102B in Land Resource Region M.

moraines generally are nearly level to gently rolling and have

many depressions and ill-defined drainageways. The steeper

slopes are on end moraines and on breaks adjacent to some of

the larger tributaries. Small outwash areas are adjacent to the

minor moraines. The dominant parent materials are silty drift,

glacial till, glacial outwash, and alluvium.

Climate

The average annual precipitation in this area is 23 to 26

inches (585 to 660 millimeters). Most of the rainfall occurs as

high-intensity, convective thunderstorms during the growing

season. Winter precipitation typically occurs as snow. The

annual snowfall is 23 to 46 inches (60 to 120 centimeters). The

average annual temperature is 43 to 49 degrees F (6 to 9

degrees C). The freeze-free period averages about 165 days and

ranges from 155 to 175 days.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 2.0%; ground water, 19.1%

Livestock—surface water, 1.6%; ground water, 2.8%

Irrigation—surface water, 16.3%; ground water, 50.6%

Other—surface water, 2.1%; ground water, 5.5%

The total withdrawals average 61 million gallons per day

(230 million liters per day). About 78 percent is from ground

water sources, and 22 percent is from surface water sources.

Precipitation is the principal source of moisture for crops. In

some years it is inadequate for maximum crop production.

Surface water is not plentiful in this area. Rural water systems

supply domestic water to an increasing number of farms and

communities in the area. The Missouri River, south of this area,

has the best quality water in this region, so it is increasingly

being used by rural water systems in the area.

A limited supply of ground water is in the glacial drift and

alluvial aquifers near the surface in this area. These aquifers

consist of unconsolidated sand and gravel. They provide fresh

or saline water that is hard and is a calcium-magnesium,

bicarbonate, and sulfate type. The median level of total

dissolved solids, 670 parts per million (milligrams per liter),

exceeds the national secondary (esthetic) standard for drinking

water. The ground water is used primarily for domestic purposes

and livestock, but some irrigation development has occurred in

areas where the water supply is more abundant. Some public

supplies are obtained from the shallow aquifers in the area.

Many private wells have high levels of nitrate plus nitrite. Most

of this contamination occurs because the wells are located

Sioux Falls are on the eastern edge. Interstate 90 bisects the

area from east to west, and Interstate 29 parallels the east edge

of the area, crossing it at the north and south ends.

Physiography

This area is in the Western Lake Section of the Central

Lowland Province of the Interior Plains. It is characterized by

glaciated, nearly level to hilly plains. It has many depressions

and ill-defined drainageways. Elevation ranges from 1,140 feet

(350 meters) on the edge of the bottom land along the Missouri

River in the southern part of the area to 1,880 feet (575 meters)

in central Lake County.

The only Hydrologic Unit Area (identified by a four-digit

number) that makes up this MLRA is Missouri-Big Sioux

(1017). The Vermillion River is just outside the western

boundary of the MLRA, and the Big Sioux River is just outside

the eastern boundary.

Geology

The major landforms in this MLRA are stagnation moraines,

end moraines, glacial outwash terraces, and flood plains. The

area is dominated by drift-covered moraines. The stagnation
320 Major Land Resource Areas

downslope from septic tank absorption fields, feedlots,

barnyards, or fertilizer storage areas.

Soils

The dominant soil order in this MLRA is Mollisols. The

soils dominantly have a mesic soil temperature regime, an ustic

soil moisture regime that borders on udic, and mixed or

smectitic mineralogy. They generally are very deep, well

drained to poorly drained, and clayey or loamy. Calciustolls

(Ethan series) and Calciustepts (Betts series) formed in till on

the steeper slopes on moraines. Calciaquolls formed in silty

drift (Wakonda series) and glacial till (Davison series) in areas

characterized by upward water movement. Haplustolls formed

in lacustrine sediments (Huntimer series), silty drift (Wentworth

and Trent series), silty drift over glacial till (Egan and Viborg

series), or glacial till (Clarno series). They also formed in

glaciofluvial deposits on outwash plains (Dempster, Graceville,

Delmont, and Enet series). Argiaquolls (Chancellor series)

formed in alluvium in wet drainageways. The soils that formed

in alluvium in depressions include Argialbolls (Tetonka series),

Argiaquolls (Worthing series), and Endoaquolls (Baltic series).

Soils that formed in stream alluvium include Haplustolls (Bon,

Davis, and Roxbury series), Endoaquolls (Lamo, Clamo, and

Salmo series), Calciaquolls (Arlo and Storla series), and

Fluvaquents (Chaska series).

Biological Resources

This area is in the western part of the tall grass prairie. Big

bluestem, little bluestem, Indiangrass, porcupinegrass, and

green needlegrass are the dominant species in the native plant

communities. Needleandthread and prairie dropseed are

important species on the steeper soils. Cattails, prairie

cordgrass, bulrush, and reed canarygrass commonly grow in

wet areas.

Some of the major wildlife species in this area are whitetailed deer, red fox, coyote, white-tailed jackrabbit, pheasant,

gray partridge, ducks, and geese. Fishing is common in the

pothole lake areas and rivers. The species of fish in the area

include walleye pike, smallmouth bass, bluegill, yellow perch,

northern pike, carp, channel catfish, and black bullhead.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 71%

Grassland—private, 16%; Federal, 1%

Forest—private, 1%

Urban development—private, 4%

Water—private, 2%

Other—private, 5%

Most of this area is in farms, and about 70 percent is

cropland used for crops grown for sale or for feeding livestock.

Corn, soybeans, alfalfa, and oats are the principal crops.

Wooded areas generally occur as narrow bands along streams

and rivers or as shelterbelts around farmsteads. Irrigation

systems are used on droughty soils in areas where water

supplies are available. Urban development is expanding around

some of the larger towns.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and

productivity of the soils, wetness, and management of soil

moisture. Conservation practices on cropland generally include

systems of crop residue management, especially no-till or

conservation tillage systems that conserve moisture and

contribute to soil quality. Other practices include terraces,

vegetative wind barriers, grassed waterways, and nutrient

management. 

102C—Loess Uplands

This area (shown in fig. 102C-1) is in Nebraska (77 percent),

South Dakota (13 percent), Iowa (6 percent), and Minnesota

(4 percent). It makes up about 11,445 square miles (29,655

square kilometers). It includes the towns or cities of Albion,

Bloomfield, Hartington, Wayne, Norfolk, West Point,

Columbus, and Fremont, Nebraska; Yankton, Sioux Falls, and

Vermillion, South Dakota; Canton, Iowa; and Luverne,

Minnesota. Interstates 29 and 90 cross parts of this MLRA.

Parts of the Santee, Winnebago, and Omaha Indian

Reservations are in this area.

Physiography

Most of this area is in the Dissected Till Plains Section of the

Central Lowland Province of the Interior Plains. The

southwestern third is in the High Plains Section of the Great

Plains Province of the Interior Plains. This MLRA has broad,

undulating to rolling ridgetops and hilly to steep valley sides.

The valleys are generally narrow, but broad flood plains and

terraces are along the major rivers and the large tributaries.

Elevation ranges from 1,100 to 2,000 feet (335 to 610 meters),

increasing from southeast to northwest. Local relief is

commonly 5 to 30 feet (2 to 9 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Elkhorn (1022), 44 percent; Missouri-Big Sioux (1017), 36

percent; Loup (1021), 9 percent; Platte (1020), 8 percent;

Missouri-Little Sioux (1023), 2 percent; and Niobrara (1015), 1

percent. The Big Sioux River forms the boundary between Iowa
of the United States 321

Climate

The average annual precipitation in this area is 23 to 30

inches (585 to 760 millimeters). Most of the rainfall occurs

as high-intensity, convective thunderstorms during the growing

season. The maximum precipitation occurs from the middle

of spring to early in autumn. Precipitation in winter occurs

as snow. The annual snowfall ranges from about 24 inches

(60 centimeters) in the southern part of the area to 34 inches (85

centimeters) in the northern part. The average annual

temperature is 43 to 51 degrees F (6 to 11 degrees C). The

freeze-free period averages about 170 days and ranges from 150

to 190 days, increasing in length from northwest to southeast.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.6%; ground water, 10.9%

Livestock—surface water, 0.1%; ground water, 0.6%

Irrigation—surface water, 22.0%; ground water, 54.3%

Other—surface water, 9.0%; ground water, 2.4%

The total withdrawals average 1,135 million gallons per day

(4,295 million liters per day). About 68 percent is from ground

water sources, and 32 percent is from surface water sources.

Precipitation is the principal source of moisture for crops. In

some years it is inadequate for maximum crop production. The

water in the Missouri River is of very good quality and is

suitable for most uses with minimal treatment. Sediment,

nutrients, and pesticides from agricultural activities impair the

other major rivers in this area, but the surface water is still used

for livestock, irrigation, public supply, and industry in parts of

the area.

Ground water is obtained from shallow alluvial and glacial

meltwater deposits of unconsolidated sand and gravel

throughout most of this area. The water in these shallow

aquifers has a median level of total dissolved solids of 350 to

390 parts per million (milligrams per liter) in the part of this

area in Nebraska and 690 parts per million (milligrams per liter)

in the part in South Dakota. It is typically a calciummagnesium-bicarbonate type of water that is very hard. The

glacial till is a poor source of ground water; yields to wells are

small to negligible, and the water is commonly highly

mineralized. Locally thick deposits of Pleistocene sand and

gravel yield moderate or moderately large supplies of goodquality water to wells. The ground water in this MLRA is used

for domestic purposes, livestock, irrigation, public supply, and

industry.

The Cretaceous-age Dakota Sandstone is at a shallow or

moderate depth in the eastern part of this area. It is tapped by

many domestic and livestock wells. Not very many irrigation

wells tap this aquifer, but a number of communities in eastern

Figure 102C-1: Location of MLRA 102C in Land Resource Region M.

and South Dakota and joins the Missouri River in this area. The

Missouri River is designated as a National Wild and Scenic

River near Vermillion, South Dakota. The Elkhorn River, a

major tributary to the Platte River in Nebraska, occurs in this

area.

Geology

Loess covers most of this area. It consists of pale brown or

light grayish brown, calcareous, silty material deposited by the

wind. The loess is mainly of Peorian age. It ranges from 6 to 70

feet (2 to 20 meters) in thickness. Deposits of glacial till

underlie the loess in most of the area. The till is more than 200

feet thick (60 meters) in some areas. Where no glacial deposits

occur, bedrock generally is at or near the surface, except in

areas where deposits of Pleistocene sand and gravel fill the

principal stream valleys. The glacial till is underlain by

deposits of Pleistocene sand and gravel in some buried bedrock

valleys. It rests directly on bedrock, however, throughout much

of the area. The Dakota Sandstone, a bedrock formation of

Cretaceous age, underlies all but the southeastern part of the

area, where rocks of Pennsylvanian age are at or near the

surface. The Dakota Sandstone is exposed in many areas along

the eastern boundary of the area for a distance of 50 miles

south from the town of Ponca. Westward from a north-south

line through Ponca, however, it is progressively more deeply

buried.
322 Major Land Resource Areas

Nebraska obtain their public supplies from it. Locally, the

Dakota Sandstone has beds of gravel at its base. Moderately

large yields can be obtained from these beds. Water quality

varies in this bedrock aquifer, depending on whether the aquifer

is being recharged locally, whether it has been leached of salts,

and whether the residence time of the water within the aquifer

has been long. Calcium is the principal cation in the ground

water where the Dakota Sandstone is being recharged locally or

where it has been leached. Sodium is the dominant cation in the

water of poorer quality where no local recharge occurs, the salts

in the aquifer have not been leached, or the water has been in

the aquifer for a long time. The water from the Dakota

Sandstone is very hard. Other bedrock formations in the area are

generally poor sources of water.

Soils

The dominant soil order in this MLRA is Mollisols. The soils

in the area dominantly have a mesic soil temperature regime, an

ustic soil moisture regime, and mixed or smectitic mineralogy.

They are shallow to very deep, moderately well drained to

somewhat excessively drained, and loamy or clayey. Haplustolls

formed in loess on uplands (Belfore, Moody, and Nora series), in

loess over outwash on uplands (Dempster and Graceville series),

in colluvium and alluvium on footslopes (Alcester series), and in

eolian deposits on uplands (Flandreau, Grovena, and Thurman

series). Endoaquolls (Colo, Gibbon, and Zook series) formed in

alluvium on flood plains. Ustorthents (Crofton series) formed in

loess in steep areas on uplands. Fluvaquents (Albaton series) and

Udifluvents (Blake and Grable series) formed in alluvium on the

Missouri River flood plain.

Biological Resources

This area supports natural prairie vegetation. Little

bluestem, big bluestem, switchgrass, western wheatgrass, and

sideoats grama characterize the vegetation on loamy soils.

Porcupine, green needlegrass, and western wheatgrass

characterize the vegetation on clayey soils on uplands.

Some of the major wildlife species in this area are mule deer,

white-tailed deer, coyote, raccoon, pheasant, bobwhite quail,

mourning dove, and meadowlark. The species of fish in the area

include smallmouth bass, bluegill, channel catfish, and black

bullhead.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 74%

Grassland—private, 16%

Forest—private, 2%

Urban development—private, 4%

Water—private, 1%

Other—private, 3%

Nearly all of this area is farmed. More than 70 percent of the

area is cropland used mainly for corn and soybeans. Feed grains

and hay crops also are widely grown. About 20 percent of the

area is irrigated. Corn, alfalfa, small grains, and grass hay are

grown extensively in the irrigated areas. The areas consisting of

hilly and steep slopes bordering the drainageways support

native grasses and shrubs used for grazing.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and tilth

of the soils, and soil moisture management. Soils that formed in

Peorian Loess are highly susceptible to water erosion. Pasture

and rangeland are subject to wind erosion and water erosion

when the plant cover is depleted by overgrazing. Conservation

practices on cropland generally include high-residue crops in

the cropping system, systems of crop residue management (such

as no-till and mulch-till systems), level terraces, contour

farming, contour stripcropping, irrigation water management,

and nutrient management. Conservation practices on pasture

and rangeland generally include fences and proper grazing

management. 

103—Central Iowa and Minnesota Till

Prairies

This area (shown in fig. 103-1) is in Minnesota (56 percent)

and Iowa (44 percent). It makes up about 27,640 square miles

(71,630 square kilometers). It includes the cities or towns of

Mankato, Marshall, Hutchinson, Minneapolis, and Willmar,

Minnesota, and Des Moines, Ames, Carroll, and Fort Dodge,

Iowa. The towns of Worthington and Fairmont and the city of

Albert Lea, Minnesota, are connected by Interstate 90, which

crosses the center of this area. Interstate 80 passes through

Ankeny and Des Moines, and Interstate 35 extends from north

of Des Moines to the cities of Minneapolis and St. Paul,

Minnesota. Numerous State and county parks and public access

areas are throughout the MLRA.

Physiography

This area is in the Western Lake Section of the Central

Lowland Province of the Interior Plains. The area is called the

“Des Moines Lobe” of the Wisconsin-age ice sheet. It is mostly

on a young, nearly level to gently rolling glaciated till plain

with moraines and glacial lake plains in some areas. The eastern

part of the area has some higher hills (moraines). Natural lakes,

marshes, and potholes occur throughout the area. Elevation

ranges from 985 to 1,315 feet (300 to 400 meters). Relief is

mainly less than 10 feet to 20 feet (3 to 6 meters), but some of

the major valleys are 165 feet (50 meters) or more below the

adjoining uplands.
of the United States 323

to southeast. Most of the rainfall occurs as high-intensity,

convective thunderstorms during the summer. Two-thirds or

more of the precipitation falls during the freeze-free period.

Snowfall is common in winter. The average annual temperature

ranges from 43 to 50 degrees F (6 to 10 degrees C). The freezefree period averages about 175 days and ranges from 155 to

200 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 9.5%; ground water, 8.9%

Livestock—surface water, 1.1%; ground water, 3.0%

Irrigation—surface water, 0.6%; ground water, 2.1%

Other—surface water, 64.6%; ground water, 10.1%

The total withdrawals average 1,485 million gallons per day

(5,620 million liters per day). About 24 percent is from ground

water sources, and 76 percent is from surface water sources. The

moderate precipitation is adequate for crops, but in years when

rainfall is below normal, yields can be reduced. Lakes, ponds,

and a few artificial reservoirs provide water and opportunities

for recreation. The surface water is abundant, but its quality

may be degraded by the nonpoint sources of sediment,

nutrients, and pesticides in runoff from agricultural land.

Ground water supplies are adequate for the domestic,

livestock, municipal, and industrial needs in this area. A

number of unconsolidated and bedrock aquifers occur in the

area. Most of the ground water used in the area is pumped from

the surficial aquifer (buried channels, glacial drift, and

alluvium) or the Ordovician and Cambrian sandstone and

dolomite in the Jordan, or Prairie du Chien-Jordan, aquifer. The

water from both of the aquifers generally meets Federal and

State drinking water standards. It is hard or very hard. The level

of total dissolved solids in the water from the surficial aquifer is

about 500 parts per million (milligrams per liter).

Soils

The dominant soil orders in this MLRA are Mollisols and, to

a lesser extent, Alfisols and Inceptisols. The soils in the area

dominantly have a mesic soil temperature regime, an aquic or

udic soil moisture regime, and mixed mineralogy. They

generally are very deep, well drained to very poorly drained,

and loamy. Hapludolls formed in loamy till on till plains and

moraines (Amiret, Clarion, Nicollet, and Ves series) and in

outwash deposits on outwash plains, terraces, and kames

(Estherville and Hawick series). Argiudolls (Le Sueur series)

and Argiaquolls (Cordova series) formed in loamy till on till

plains and moraines. Endoaquolls (Canisteo, Glencoe, and

Webster series) and Calciaquolls (Harps series) formed in

loamy till and/or local alluvium on till plains and in swales and

Figure 103-1: Location of MLRA 103 in Land Resource Region M.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Minnesota (0702), 35 percent; Des Moines (0710), 32 percent;

Upper Mississippi-Iowa-Skunk-Wapsipinicon (0708), 14

percent; Mississippi Headwaters (0701), 11 percent; Upper

Mississippi-Black-Root (0704), 4 percent; and Missouri-Little

Sioux (1023), 4 percent. The major rivers that drain the MLRA

include the Blue Earth, Boone, Cottonwood, Des Moines,

Lizard, Minnesota, and Raccoon Rivers. The Minnesota, Crow,

and Cannon Rivers are National Wild and Scenic Rivers in this

MLRA.

Geology

This area is covered with glacial till, outwash, and glacial

lake deposits. Recent alluvium consisting of clay, silt, sand,

and gravel fill the bottoms of most of the major river valleys.

Paleozoic bedrock sediments, primarily shale and limestone,

underlie the glacial deposits in most of the area. Some

Precambrian Sioux Quartzite is exposed on the western edge of

the area, in southwestern Minnesota.

Climate

The average annual precipitation in most of this area is 23 to

35 inches (585 to 890 millimeters), increasing from northwest
324 Major Land Resource Areas

depressions. Endoaquolls also formed in alluvium on flood

plains (Coland series). Hapludalfs (Hayden and Lester series)

and Eutrudepts (Storden series) formed in loamy till on

moraines.

Biological Resources

This area supports natural prairie vegetation characterized

by little bluestem, Indiangrass, and switchgrass. Little

bluestem, Indiangrass, and needlegrass grow on sandy,

droughty soils. Little bluestem, sideoats grama, blue grama, and

scattered bur oak, juniper, and sumac grow on very shallow

soils.

Some of the major wildlife species in this area are whitetailed deer, fox, beaver, muskrat, rabbit, squirrel, mink, Canada

goose, pheasant, and gray partridge. The most common species

of fish in the area are walleye, northern pike, largemouth bass,

bluegill, crappie, yellow perch, and sunfish.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 80%

Grassland—private, 5%

Forest—private, 3%

Urban development—private, 6%

Water—private, 2%

Other—private, 4%

Nearly all of this area is in farms, and about four-fifths is

cropland. The proportion of cropland is highest in the southern

part of the area. Corn, soybeans, and other feed grains are the

major crops. Some of the cropland is used for hay. Dairy

farming is a more common enterprise in the northern part of the

MLRA than in the southern part. Forested areas occur as narrow

bands on steep slopes bordering stream valleys and as wet areas

on bottom land. Less than one-tenth of the area is used for

urban development. Many natural lakes occur in this area, and

numerous bogs, swales, and circular depressions indicate sites

of previously ponded water. Much of the area is currently

drained by tile. Extensive drainage ditches provide outlets for

the tile drains. Many areas in this MLRA are used for outdoor

recreation.

The major resource concerns are water erosion, depletion of

organic matter in the soils, excess surface and subsurface water,

and poor water quality. Conservation practices on cropland

generally include systems of crop residue management

(especially no-till, strip-till, and mulch-till systems), cover

crops, surface and subsurface drainage systems, nutrient and

pest management, grassed waterways, buffer strips, and

development of wildlife habitat. 

104—Eastern Iowa and Minnesota Till

Prairies

This area (shown in fig. 104-1) is in Iowa (74 percent),

Minnesota (22 percent), and Wisconsin (4 percent). It makes up

about 9,660 square miles (about 25,040 square kilometers). The

larger cities and towns in this area are Mason City, Cedar Falls,

Waterloo, and Cedar Rapids, Iowa, and Austin, Minnesota.

Interstate 90 passes through Austin, Minnesota, in the northern

end of the area. The small part of this area that crosses into

Wisconsin from Minnesota does so at Red Wing, Minnesota. A

few State parks are in the area.

Physiography

This area is in the Central Lowland Province of the Interior

Plains. Almost all of the area is in the Dissected Till Plains

Section of the province, but parts of the western edge are in the

Western Lake Plain Section, and the small part of the area in

Wisconsin is in the Wisconsin Driftless Section. The landscape

is a nearly level to gently rolling glaciated plain with long

slopes. The natural drainage network is well established and

commonly described as dendritic, resulting in few lakes and

ponds. Subsurface tile drainage lines are commonly used to

Figure 104-1: Location of MLRA 104 in Land Resource Region M.
of the United States 325

good quality and is suitable for all uses. It is used mainly for

public supplies and industry.

The supply of ground water is adequate for the livestock,

domestic, municipal, and industrial needs in this area. A

number of unconsolidated and bedrock aquifers are in the area.

Most of the ground water used in this area is pumped from

either the surficial aquifer (buried channels, glacial drift, and

alluvium) or the Ordovician and Cambrian sandstone and

dolomite in the Jordan, or Prairie du Chien-Jordan, aquifer. The

water from both aquifers generally meets Federal and State

drinking water standards. The median level of 850 parts per

million (milligrams per liter) total dissolved solids in the Jordan

aquifer does exceed the secondary (esthetic) standard for

drinking water in Iowa. The level of total dissolved solids is

much lower in the Prairie du Chien-Jordan aquifer in

Minnesota. Water in both aquifers is hard or very hard, and the

level of total dissolved solids in the water from the surficial

aquifer is about 500 parts per million (milligrams per liter).

Soils

The dominant soil orders in this MLRA are Mollisols and

Alfisols. The soils in the area dominantly have a mesic soil

temperature regime, an aquic or udic soil moisture regime,

and mixed mineralogy. They generally are very deep, well

drained to very poorly drained, and loamy. Hapludolls (Floyd,

Kenyon, Marquis, Ostrander, and Readlyn series) and

Hapludalfs (Bassett, Kasson, and Racine series) formed in

loamy sediments over till on uplands. Argiudolls (Dinsdale

series) formed in loess over till on uplands. Endoaquolls

(Maxfield and Tripoli series) formed in loamy and silty

sediments over till on uplands.

Biological Resources

This area supports prairie vegetation. Big bluestem and

Indiangrass are dominant on the well drained soils in rolling

areas. Switchgrass, prairie cordgrass, and prairie dropseed are

better adapted to the somewhat poorly drained soils.

Switchgrass, sedges, and rushes grow on poorly drained soils in

draws or valleys. Common cattails grow on swampy sites. Little

bluestem, porcupinegrass, and sand lovegrass grow on sandy,

rocky, dry sites. Forbs, such as clovers, phlox, sunflower,

gayfeather, and goldenrod, grow on the more productive soils.

Roundhead lespedeza, spiderwort, and flowering spurge grow

on droughty soils. Loosestrife, bedstraw, milkweed, and

tickclover are water-tolerant species that grow on wet soils.

Some of the major wildlife species in this area are whitetailed deer, beaver, otter, muskrat, squirrel, mink, pheasant,

gray partridge, great blue heron, American egret, mallard, and

teal. The species of fish in the area include smallmouth bass,

catfish, northern pike, black bullhead, bluegill, sunfish, and

rough fish.

lower water tables and increase crop production. Karst

topography is common in this area. Elevation ranges from 985

to 1,310 feet (300 to 400 meters). Local relief is 10 to 20 feet (3

to 6 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Upper Mississippi-Iowa-Skunk-Wapsipinicon (0708), 62

percent; Upper Mississippi-Maquoketa-Plum (0706), 19

percent; Upper Mississippi-Black-Root (0704), 17 percent; and

Chippewa (0705), 2 percent. The major rivers that drain the area

include the Cannon, Zumbro, Root, and Cedar Rivers in

Minnesota and the Beaver, Cedar, Winnebago, Shell Rock, and

Wapsipinicon Rivers in Iowa.

Geology

This area is covered with glacial till and outwash deposits.

Recent alluvium consisting of clay, silt, sand, and gravel fills

the major river valleys. Paleozoic bedrock sediments, primarily

shale and limestone, underlie most of the area. A shallow depth

to limestone results in karst topography in much of the area.

Some limestone units containing fossils are exposed in road

cuts in the northeast corner of the area and along the major

rivers in the part of the area in Iowa. Bedrock units also are

exposed on the Mississippi River bluffs near Red Wing,

Minnesota.

Climate

The average annual precipitation in most of this area is 29 to

37 inches (735 to 940 millimeters). Most of the rainfall occurs

as high-intensity, convective thunderstorms during the summer.

More than two-thirds of the precipitation falls during the

growing season. Precipitation in winter occurs mainly as snow.

The average annual temperature is 44 to 50 degrees F (7 to 10

degrees C). The freeze-free period averages about 180 days and

ranges from 160 to 195 days.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 6.5%; ground water, 27.6%

Livestock—surface water, 1.6%; ground water, 4.2%

Irrigation—surface water, 0.0%; ground water, 0.3%

Other—surface water, 36.3%; ground water, 23.4%

The total withdrawals average 365 million gallons per day

(1,380 million liters per day). About 56 percent is from ground

water sources, and 44 percent is from surface water sources.

Precipitation is generally adequate for crops, but in years when

the precipitation is below normal, yields can be reduced. Water

is generally abundant in the many rivers in the area. It is of
326 Major Land Resource Areas

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 80%

Grassland—private, 5%

Forest—private, 6%

Urban development—private, 5%

Water—private, 1%

Other—private, 3%

Nearly all of this area is in farms, and about four-fifths is

cropland. Much of the area is drained by tile. Extensive

drainage ditches provide outlets for the tile drains. Corn,

soybeans, other feed grains, and hay are the major crops.

Raising and feeding hogs and beef cattle and dairying are

important enterprises. The forestland in the area is mainly on

wet bottom land and on steep slopes bordering stream valleys.

The major resource concerns are water erosion, depletion of

organic matter in the soils, excess surface and subsurface water,

and poor water quality. Many of the wet soils require artificial

drainage for good growth of the field crops commonly grown in

the area. Conservation practices on cropland generally include

systems of crop residue management (especially no-till, striptill, and mulch-till systems), cover crops, surface and subsurface

drainage systems, nutrient and pest management, grassed

waterways, terraces, manure management, pasture and hayland

planting, and grade-stabilization structures. 

105—Northern Mississippi Valley Loess

Hills

This area (shown in fig. 105-1) is in Wisconsin (52 percent),

Iowa (23 percent), Minnesota (20 percent), and Illinois (5

percent). It makes up about 17,950 square miles (about 46,515

square kilometers). The major cities or towns in the area are

Decorah, Dubuque, Maquoketa, and Clinton, Iowa; Rochester

and Winona, Minnesota; and Eau Claire, Menomonie, Prairie

du Chien, Platteville, and Richland Center, Wisconsin.

Interstate 90 crosses parts of this MLRA. The Savanna Army

Depot Military Reservation, along the part of the Mississippi

River in Illinois, and the Fort McCoy Military Reservation, in

Wisconsin, are in the MLRA. The Richard J. Dorer Memorial

State Forest makes up almost the entire northeast one-quarter of

the part of this area in Minnesota. Numerous State parks are

throughout the area. Much of the Upper Mississippi National

Wildlife Refuge is in this MLRA.

Figure 105-1: Location of MLRA 105 in Land Resource Region M.

Physiography

This area is in the Wisconsin Driftless Section of the Central

Lowland Province of the Interior Plains. In Wisconsin, this area

is often referred to as the “Driftless Area” because it has

undergone only limited landscape formation by glacial ice. The

area consists mostly of gently sloping to rolling summits with

steeper valley walls that join small to very large flood plains.

Scenic landscapes are characteristic of the area. They include

deep valleys, abundant rock outcrops, high bluffs, caves,

crevices, and sinkholes. Stream valleys are deep, narrow, and Vshaped and have irregular slopes and steep cliffs. The valleys

commonly take abrupt, sharp-angled turns, indicating that the

local drainage network is controlled by joint patterns in the

underlying bedrock. Elevation ranges from 660 feet (200

meters) on the valley floors to 1,310 feet (400 meters) on the

highest ridges. Local relief is mainly 10 to 20 feet (3 to 6

meters), but it is as much as 50 to 100 feet (15 to 30 meters) on

valley walls along the major streams and is as much as 250 feet

(75 meters) on the Mississippi River bluffs above the river

valley floor.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:
of the United States 327

water sources, and 91 percent is from surface water sources. In

most years the moderate precipitation is adequate for crops and

forage, but in years of little or no precipitation, yields are

reduced on soils that are shallow over bedrock. The many

springs, streams, and farm ponds are additional sources of

surface water in the area. The surface water is abundant and

generally is of good quality. Poor water quality in stream

reaches is primarily the result of nonpoint sources of sediment,

nutrients, and pesticides from agricultural land or wastewater

discharges downstream from the larger cities.

Ground water is abundant in glacial outwash deposits in

most of the river valleys in this area. This water is moderately

hard or hard but is generally of very good quality. The level of

total dissolved solids is typically less than 250 parts per million

(milligrams per liter). The supply of ground water varies in the

uplands. The sandstone and dolomite layers in the Jordan and

Prairie du Chien aquifers usually provide adequate yields to

wells. The water from these aquifers is suitable for all uses,

although the level of total dissolved solids approaches 1,000

parts per million (milligrams per liter) in some areas.

Soils

The dominant soil orders in this MLRA are Alfisols and

Entisols and, to a lesser extent, Mollisols. The soils in the area

dominantly have a mesic soil temperature regime, a udic soil

moisture regime, and mixed mineralogy. They generally are

moderately deep to very deep, well drained or moderately well

drained, and loamy. Hapludalfs formed in loess (Downs,

Fayette, Mt. Carroll, and Seaton series) or loess over residuum

(Dubuque, La Farge, Norden, and Nordness series) on uplands

and benches. Paleudalfs (Valton series) formed in loess over

residuum on uplands. Argiudolls (Tama series) formed in loess

on uplands and terraces. Udifluvents (Chaseburg series) formed

in alluvium on flood plains and alluvial fans. Udipsamments

(Plainfield series) formed in glaciofluvial deposits on outwash

plains, terraces, and valley trains.

Biological Resources

The soils on uplands support native hardwoods. Oak,

hickory, and sugar maple are the dominant species. Big

bluestem, little bluestem, and scattered oak trees grow on some

sites. The soils on lowlands support mixed hardwoods, mainly

elm, cottonwood, river birch, ash, silver maple, and willow.

Sedge and grass meadows and scattered trees grow on some of

the wetter lowlands.

Some of the major wildlife species in this area are whitetailed deer, coyote, gray fox, red fox, beaver, raccoon, skunk,

muskrat, opossum, fisher, otter, mink, cottontail, fox squirrel,

gray squirrel, red squirrel, Canada goose, sandhill crane, bald

eagle, red-shouldered hawk, goshawk, peregrine falcon, osprey,

Cooper’s hawk, turkey vulture, turkey, ruffed grouse,

Upper Mississippi-Maquoketa-Plum (0706), 38 percent; Upper

Mississippi-Black-Root (0704), 33 percent; Wisconsin (0707),

19 percent; Rock (0709), 7 percent; Chippewa (0705), 2

percent; and Upper Mississippi-Iowa-Skunk-Wapsipinicon

(0708), 1 percent. The Mississippi River flows through much of

this area, forming the boundaries between Minnesota and

Wisconsin and between Iowa and Illinois. The Kickapoo,

Wisconsin, and Pecatonica Rivers are in the part of this area in

Wisconsin. The Zumbro, Whitewater, and Root Rivers flow into

the Mississippi River from the part in Minnesota. The Upper

Iowa, Turkey, Yellow, Volga, and Maquoketa Rivers all flow

into the Mississippi River from the part in Iowa. The Apple,

Plum, and Rock Rivers are in the southeast corner of the area, in

Illinois.

Geology

This area is in the “Driftless Area” of southwestern

Wisconsin, but it shows some evidence of glaciation, especially

in the western part. Cambrian sandstone, with some shale and

dolomite layers, is exposed in the northern part of the area. The

sandstone also underlies Ordovician sediments in the more

deeply eroded river valleys. Sandstone, shale, dolomite, and

limestone units of the St. Peter Formation and Prairie du Chien

Group are at the surface, in road cuts, and in valley walls along

the major rivers in the part of the area in Wisconsin and

Minnesota. In the southern part of the area, younger Ordovician

shale and dolomite units occur at the surface. Some karst areas

have formed where the carbonate rocks are near the surface.

Loess deposits cover many of the bedrock units in this area.

Climate

The average annual precipitation in most of this area is 30 to

38 inches (760 to 965 millimeters). Two-thirds or more of the

precipitation falls during the freeze-free period. Most of the

rainfall occurs as high-intensity, convective thunderstorms

during the summer. Snowfall is common in winter. The average

annual temperature is 42 to 50 degrees F (6 to 10 degrees C).

The freeze-free period averages about 175 days and ranges from

145 to 205 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 2.1%; ground water, 4.0%

Livestock—surface water, 0.2%; ground water, 1.2%

Irrigation—surface water, 0.0%; ground water, 0.2%

Other—surface water, 88.2%; ground water, 3.9%

The total withdrawals average 2,650 million gallons per day

(10,030 million liters per day). About 9 percent is from ground
328 Major Land Resource Areas

woodcock, great horned owl, wood duck, hooded merganser,

pileated woodpecker, and red-bellied woodpecker.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 49%

Grassland—private, 14%; Federal, 1%

Forest—private, 27%

Urban development—private, 4%

Water—private, 2%

Other—private, 2%; Federal, 1%

Nearly all of this area is farmed. About one-half of the area is

cropland, and 15 percent is permanent pasture. Cash crops, such

as corn and soybeans, and feed grains and forage crops for dairy

cattle and other livestock are the principal crops. About onefourth of the area, mainly the more sloping parts, consists of

farm woodlots used for commercial timber production or for

farm products. The Mississippi River and its major tributaries

provide opportunities for recreation.

The major resource concerns are water erosion, depletion of

organic matter in the soils, and poor water quality.

Conservation practices on cropland generally include systems

of crop residue management (especially no-till, strip-till, and

mulch-till systems), cover crops, nutrient and pest management,

contour stripcropping, grassed waterways, terraces, manure

management, pasture and hayland planting, tree planting, and

grade-stabilization structures. 

106—Nebraska and Kansas Loess-Drift

Hills

This area (shown in fig. 106-1) is in Nebraska (52 percent)

and Kansas (48 percent). It makes up about 10,920 square miles

(28,295 square kilometers). It includes the town of Beatrice,

Nebraska; the city of Lincoln, Nebraska; and the cities of

Topeka and Lawrence, Kansas. Interstate 80 crosses the

northern part this MLRA, passing through an area just north of

Lincoln, and Interstates 70 and 470 pass through Topeka and

Lawrence, Kansas, in the southern part of the MLRA. The Iowa

Sac and Fox, Kickapoo, and Potawatomi Indian Reservations

are in the part of this area in Kansas. Part of the Iowa Sac and

Fox Reservation is in Nebraska. The Homestead National

Monument, commemorating pioneer life on the prairie, is just

west of Beatrice, Nebraska.

Figure 106-1: Location of MLRA 106 in Land Resource Region M.

Physiography

This area is almost entirely in the Dissected Till Plains

Section of the Central Lowland Province of the Interior Plains.

The southern tip is in the Osage Plains Section of the same

province and division. Interstate 70 is close to the boundary

between these two sections in this MLRA. This area is a

dissected glacial drift plain. Ridgetops are broad and smooth,

and slopes are nearly level to strongly sloping. Stream valleys

are bordered by relatively narrow bands of hilly and steep

slopes. Valley floors are typically narrow, except along the

larger rivers and their primary tributaries. Elevation ranges from

980 to 1,650 feet (300 to 505 meters), increasing from east to

west. Local relief is mainly 10 to 20 feet (3 to 6 meters), but

some of the larger valley floors are 80 to 160 feet (25 to 50

meters) or more below the level of the adjacent uplands.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Kansas (1027), 51 percent; Missouri-Nishnabotna (1024), 32

percent; and Platte (1020), 17 percent. The Little Nemaha River

and the North Fork of the Big Nemaha River flow into the

Missouri River, which is just east of the part of this area in

Nebraska. The Big Blue River flows through Beatrice,
of the United States 329

bicarbonate and is very hard. The level of total dissolved solids

varies considerably in the water in the glacial drift. The water in

the alluvial deposits has a median level of 390 parts per million

(milligrams per liter) total dissolved solids. In some areas deep

wells in glacial drift provide very hard water that contains more

than 700 parts per million (milligrams per liter) total dissolved

solids. Many communities and households obtain water from

the Dakota Formation. This water is very hard and has a median

level of 840 parts per million (milligrams per liter) total

dissolved solids. The public water supply for Lincoln,

Nebraska, is pumped from alluvium along the Platte River,

almost 30 miles east of the city.

Soils

The dominant soil orders in this MLRA are Mollisols,

Alfisols, and Entisols. The soils in the area dominantly have a

mesic soil temperature regime, a udic soil moisture regime, and

mixed or smectitic mineralogy. They generally are very deep,

well drained or moderately well drained, and loamy or clayey.

Hapludolls formed in alluvium on flood plains (Kennebec

series), in colluvium on footslopes and alluvial fans (Judson

series), and in loess on uplands (Marshall series). Argiudolls

formed in loess (Aksarben and Wymore series), till (Burchard,

Morrill, Pawnee, and Shelby series), and colluvium and/or

residuum (Martin series) on uplands. Udifluvents (Nodaway

series) formed in alluvium on flood plains. Udorthents

(Steinauer series) formed in till on uplands. Hapludalfs formed

in loess on uplands and stream terraces (Yutan and Otoe series)

and in till on uplands (Malmo series).

Biological Resources

This area supports grassland vegetation characterized by mid

and tall grasses. Big bluestem, little bluestem, switchgrass,

Indiangrass, porcupinegrass, and sideoats grama are the

dominant species on silty soils in the uplands. Clayey soils in

the uplands support a similar plant community but have a

higher percentage of switchgrass and have some wildrye. Green

ash, hackberry, oak, boxelder, black walnut, and maple trees

grow along streams and intermittent drainageways.

Some of the major wildlife species in this area are whitetailed deer, raccoon, opossum, tree squirrel, pheasant, bobwhite

quail, and mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 62%

Grassland—private, 22%; Federal, 1%

Forest—private, 6%

Urban development—private, 5%

Water—private, 2%

Other—private, 2%

Nebraska, and on into the part of this area in Kansas. SaltWahoo Creeks flow through Lincoln and Wahoo and on into

the Platte River in the northern part of the area. The Big Blue

joins the Black Vermillion River at Tuttle Creek Lake in the

southern end of the MLRA, in Kansas. The Soldier and

Delaware Rivers also are in the part of the MLRA in Kansas.

Geology

Loess covers the surface of almost all of the uplands in this

MLRA. Glacial drift underlies the loess. Alluvial clay, silt, sand,

and gravel are deposited in all of the stream and river valleys.

The alluvial deposits can be extensive in the major river

valleys. Paleozoic sandstone, shale, and limestone units are

exposed in a few road cuts and in the walls of valleys along the

major streams on the east side of the area, near the bluffs along

the Missouri River. Limestone and shale (clay) quarries are in

this MLRA.

Climate

The average annual precipitation in most of this area is 28 to

40 inches (710 to 1,015 millimeters), increasing from northwest

to southeast. About three-fourths of the precipitation falls as

high-intensity, convective thunderstorms from late in spring

through early in autumn. The scant precipitation in winter

occurs mainly as snow. The average annual temperature is 50 to

55 degrees F (10 to 13 degrees C). The freeze-free period

averages about 195 days and ranges from 175 to 215 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 6.5%; ground water, 18.7%

Livestock—surface water, 1.3%; ground water, 2.5%

Irrigation—surface water, 11.4%; ground water, 31.9%

Other—surface water, 13.6%; ground water, 14.1%

The total withdrawals average 485 million gallons per day

(1,835 million liters per day). About 67 percent is from ground

water sources, and 33 percent is from surface water sources.

Precipitation is generally adequate for crops, but in years of

little or no precipitation, yields are reduced. The supply of both

surface and ground water is limited in this area. Small areas

along some of the perennial streams are irrigated. Small ponds

and reservoirs are important sources of water for livestock. The

surface water in this area is generally of good quality, but it

typically is not used for drinking because of the variability of

the supply. Many streams flow only in direct response to

rainfall.

Shallow wells in glacial drift and in alluvium in stream

valleys supply water for domestic and livestock needs on most

farms. This water primarily contains calcium, magnesium, and
330 Major Land Resource Areas

Nearly all of this area is farmland, and about two-thirds is

cropland. The cropland is more extensive on the less sloping

soils that formed in loess than on other soils. Wheat and corn

are important cash crops, but grain sorghum, soybeans, and

alfalfa and other hay crops are grown on a large percentage of

the area. Most of the grain and hay is fed to livestock on the

farms where it is grown. About one-fourth of the area is used as

pasture or range. Pastures of native grasses are more extensive

on the strongly sloping to steep soils that formed in glacial till

than on other soils. Pastures of introduced grasses and legumes

are on the more productive soils, and native grasses are

common on the more sloping, shallow soils. Native woodland

is confined to narrow bands bordering drainageways and

streams and to some nearly level, wet soils on bottom land.

The major soil resource concerns are water erosion and

maintenance of the content of organic matter in the soils. The

resource concerns on pasture and rangeland are plant

productivity, health, and vigor; noxious and invasive plants;

and inadequate wildlife habitat. Conservation practices on

cropland generally include high-residue crops in the cropping

system, systems of crop residue management (such as no-till,

strip-till, and mulch-till systems), gradient terraces and grassed

waterways, underground outlets, contour farming, conservation

crop rotations, and nutrient and pest management.

Conservation practices on rangeland and pasture generally

include prescribed grazing, brush management, management of

upland wildlife habitat, and proper distribution of watering

facilities. 

107A—Iowa and Minnesota Loess Hills

This area (shown in fig. 107A-1) is in Iowa (89 percent) and

Minnesota (11 percent). It makes up about 4,470 square miles

(11,590 square kilometers). The towns of Le Mars, Sioux

Center, Cherokee, and Spencer, Iowa, and Adrian and

Lismore, Minnesota, are in this MLRA. Interstate 90 passes

through the northern part of the MLRA. The area has only a

few State parks.

Physiography

This area is in the Central Lowland Province of the Interior

Plains. The western half of the area is in the Dissected Till

Plains Section of the province, and the eastern half is in the

Western Lake Section. This MLRA is mostly an undulating to

rolling glaciated plain with some nearly level, broad ridgetops

and some steep slopes bordering the major stream valleys.

Nearly level, broad valley floors are along a few large rivers.

The natural drainage network is well established and commonly

is described as dendritic, resulting in few lakes and ponds.

Elevation ranges from 1,115 feet (340 meters) in the lowest

Figure 107A-1: Location of MLRA 107A in Land Resource Region M.

valleys to 1,700 feet (520 meters) on the highest ridges. Local

relief is mainly 10 to 100 feet (3 to 30 meters), but valley floors

can be 80 to 200 feet (25 to 60 meters) below the adjacent

uplands. Also, some upland flats and valley floors have local

relief of only 3 to 6 feet (1 to 2 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Missouri-Little Sioux (1023), 74 percent; Missouri-Big Sioux

(1017), 25 percent; and Des Moines (0710), 1 percent. The

Rock River, a tributary of the Big Sioux River, and the Little

Sioux and Floyd Rivers, tributaries of the Missouri River, drain

this MLRA.

Geology

The western half of this MLRA is underlain by pre-Illinoian

glacial till, which was deposited more than 500,000 years ago

and has since undergone extensive erosion and dissection. The

eastern half is underlain by the much younger Wisconsin-age

till layer that was deposited between 20,000 and 30,000 years

ago. Both till surfaces are covered by about 4 to 20 feet (1 to 6

meters) of loess on the hillslopes and by Holocene alluvium in

the drainageways. The Quaternary deposits range from 150 to

450 feet (45 to 135 meters) in thickness and are underlain by

Cretaceous bedrock consisting of sandstone and shale.
of the United States 331

of 824 parts per million (milligrams per liter) and is very hard.

Other bedrock formations in Iowa are very deep, and wells in

these formations generally are not economical. Precambrian

Sioux Quartzite is near the surface in the part of this area in

Minnesota, and it contains good-quality water where it is not in

contact with the Cretaceous sediments. Well yields vary

dramatically, depending on how many interconnected joints and

fractures are penetrated by the well.

Soils

The dominant soil order in this MLRA is Mollisols. The

soils in the area dominantly have a mesic soil temperature

regime, an aquic or udic soil moisture regime, and mixed

mineralogy. Hapludolls (Annieville, Everly, Galva, McCreath,

Primghar, and Sac series) and Endoaquolls (Gillett Grove, Letri,

and Marcus series) formed in loess or loess over till on uplands.

Hapludolls (Moneta series) also formed in till on steeply

sloping valley slopes, and Endoaquolls (Havelock series) also

formed in alluvium on flood plains.

Biological Resources

Prairies in this area support tall grasses on moist soils and

xeric short grasses on uplands. Grama, muhly, lovegrass, and

wheatgrass commonly grow beside the more familiar little

bluestem, big bluestem, Indiangrass, and wildrye. The prairie

forbs in the area include fragrant false indigo, showy milkweed,

woolly milkweed, western prairie fringed orchid, dotted blazing

star, Maximilian sunflower, ground plum, and wild prairie

onion. Wooded areas have become more extensive in this area,

making up 1 percent of the current landscape as compared to

0.2 percent in the mid-1800s. Wooded areas on uplands

commonly support bur oak, red oak, and hackberry. Those on

bottom land support slippery elm, cottonwood, willow, and

plum.

The wildlife species in this MLRA include Great Plains toad,

bobcat, prairie rattlesnake, prairie skink, smooth green snake,

pygmy shrew, and northern grasshopper mouse on the prairies

and blue grosbeak, pine siskin, redbelly snake, and

Woodhouse’s toad in the wooded areas.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 84%

Grassland—private, 7%

Forest—private, 1%

Urban development—private, 4%

Water—private, 1%

Other—private, 3%

Nearly all of this area is farmland, and more than four-fifths

is cropland, which is used mainly for corn, soybeans, other feed

Climate

The average annual precipitation in this area is 26 to 31

inches (660 to 790 millimeters). Most of the rainfall occurs as

high-intensity, convective thunderstorms during the growing

season. About 10 percent of the precipitation occurs as snow in

the winter. The average annual temperature is 44 to 48 degrees

F (7 to 9 degrees C). The freeze-free period averages about 165

days and ranges from 155 to 175 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 8.2%; ground water, 31.2%

Livestock—surface water, 3.6%; ground water, 57.0%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 0.0%; ground water, 0.0%

The total withdrawals average 12 million gallons per day (45

million liters per day). About 88 percent is from ground water

sources, and 12 percent is from surface water sources.

Precipitation is the principal source of moisture for crops.

Sediment, nutrients, and pesticides from agricultural activities

impair the major streams and rivers in this area. The surface

water, however, is still used for livestock and public supplies in

some parts of the area.

Ground water is obtained from buried channel aquifers,

glacial drift aquifers, and alluvial deposits of unconsolidated

sand and gravel throughout most of this area. The glacial till is

a poor source of ground water; yields to wells are small or

negligible, and the water commonly is highly mineralized. The

buried channels are sources of moderate or moderately large

supplies of generally good-quality water. The mineral content

of the water may be high if this aquifer is hydraulically

connected to bedrock aquifers beneath it. Alluvial deposits are

extensive along the Rock River in the part of this area in

Minnesota. This aquifer can be a source of large supplies of

generally good-quality water. It has water with a median level

of 350 parts per million (milligrams per liter) total dissolved

solids. The water in the shallow aquifers in Iowa has a median

level of total dissolved solids of about 500 parts per million

(milligrams per liter). The ground water in this MLRA is very

hard and is used for domestic purposes, livestock, and public

supply.

The Cretaceous-age Dakota Sandstone Formation is at a

shallow or moderate depth in this area. It is tapped by many

domestic and livestock wells. Not very many irrigation wells

tap this aquifer. In areas where more shallow aquifers do not

occur, a number of communities in northwestern Iowa obtain

their public supplies from this aquifer. Locally, the base of the

Dakota Formation contains beds of gravel from which

moderately large yields of water can be obtained. The water in

the aquifer in Iowa has a median level of total dissolved solids
332 Major Land Resource Areas

grains, and hay. Much of this area is drained by tile. Extensive

drainage ditches provide outlets for the tile drains. The small

acreage of woodland in the area is mainly on wet bottom land

and on steep slopes bordering stream valleys.

The major resource concerns are water erosion, depletion of

organic matter in the soils, and poor water quality. Many of the

wet soils require artificial drainage for good growth of field

crops. Conservation practices on cropland generally include

systems of crop residue management (especially no-till, striptill, and mulch-till systems), cover crops, subsurface drainage

systems, nutrient and pest management, grassed waterways,

terraces, manure management, pasture and hayland planting,

and grade-stabilization structures. 

107B—Iowa and Missouri Deep Loess

Hills

This area (shown in fig. 107B-1) is in Iowa (53 percent),

Missouri (32 percent), Nebraska (12 percent), and Kansas (3

percent). It makes up about 14,410 square miles (37,335 square

kilometers). It includes the cities or towns of Atlantic, Council

Bluffs, and Sioux City, Iowa; St. Joseph, Kansas City,

Independence, and Marshall, Missouri; Atchison, Leavenworth,

and Kansas City, Kansas; and Omaha, Nebraska. Interstates 29,

35, 70, and 80 cross different parts of this area. Fort

Leavenworth Military Reservation and parts of the Winnebago

and Omaha Indian Reservations are in this MLRA. A number of

State parks are throughout the area, and a number of national

wildlife refuges are in the area, especially along the Missouri

River.

Physiography

This area is almost entirely in the Dissected Till Plains

Section of the Central Lowland Province of the Interior Plains.

The farthest southern part of the area in Missouri is in the

Osage Plains Section of the same province and division. Slopes

are mostly rolling to hilly, but some broad ridgetops are nearly

level to undulating. Slopes bordering the major stream valleys

are steep. Nearly level, broad valley floors are along a few large

rivers. Elevation ranges from 600 feet (185 meters) where the

Missouri River exits the area to 1,565 feet (475 meters) on the

highest ridges. Local relief is mainly 10 to 100 feet (3 to

30 meters), but valley floors can be 80 to 300 feet (25 to 90

meters) below the adjacent uplands. Also, some upland flats

and valley floors have local relief of only 3 to 6 feet (1 to 2

meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Missouri-Nishnabotna (1024), 45 percent; Missouri-Little Sioux

(1023), 33 percent; Lower Missouri (1030), 15 percent; Des

Moines (0710), 2 percent; Platte (1020), 2 percent; CharitonFigure 107B-1: Location of MLRA 107B in Land Resource Region M.

Grand (1028), 2 percent; and Missouri-Big Sioux (1017), 1

percent. A small part of the Kansas (1027) and Elkhorn (1022)

Hydrologic Unit Areas also occur in this MLRA. The Missouri

River forms the “centerline” of this MLRA. The major

tributaries that join the Missouri River in this area include, from

north to south, the Floyd, Little Sioux, Soldier, Boyer, Platte

(Nebraska), Nishnabotna, Little Nemaha, Tarkio, Big Nemaha,

Nodaway, Platte and Little Platte (Missouri), Kansas, Grand,

and Thompson Rivers.

Geology

This area includes the Missouri Alluvial Plain, the Loess

Hills, and part of the Southern Iowa Drift Plain landform

regions of Iowa. Most of the area is overlain by loess deposits

that reach a thickness of 65 to 200 feet (20 to 60 meters) in the

Loess Hills and thin to about 20 feet (6 meters) in the eastern

part of the area. The loess is underlain by pre-Illinoian till,

which was deposited more than 500,000 years ago and has

since undergone extensive erosion and dissection. In the Loess

Hills, Holocene cycles of erosion and deposition, or “cut and

fill,” have produced deeply incised gullies and fine grained

alluvial deposits. The Quaternary overburden ranges from 150

to 450 feet (45 to 135 meters) in thickness throughout most of

the area, but it is generally less than 150 feet (45 meters) thick

in the southeastern part of the area. The glacial materials are

underlain by Pennsylvanian and Cretaceous bedrock, which

consists of shale, mudstones, and sandstones.
of the United States 333

Nebraska is 824 and 840 parts per million (milligrams per liter),

respectively, and the water is very hard.

The Jordan aquifer is the most extensively used aquifer in

Iowa. It consists of Ordovician-Cambrian sandstone and

dolomite beds. Its water has a median level of total dissolved

solids that exceeds 800 parts per million (milligrams per liter)

and may contain levels of radium that exceed the national

standards for drinking water. Some communities in the part of

this area in Iowa depend on this aquifer for public supplies,

even though the wells are very deep. Paleozoic units serve as

aquifers in the parts of this area in southeastern Nebraska and

northwestern Missouri. Water from these aquifers has a median

level of total dissolved solids of 1,300 parts per million

(milligrams per liter) in Nebraska. Many farmers and

communities in Missouri have abandoned wells in these units

because of high levels of dissolved salts.

Soils

The dominant soil orders in this MLRA are Mollisols and, to

a lesser extent, Alfisols and Entisols. The soils in the area

dominantly have a mesic soil temperature regime, an aquic or

udic soil moisture regime, and mixed mineralogy. They

generally are very deep, well drained or moderately well

drained, and silty or loamy. Well drained and moderately well

drained, gently sloping to strongly sloping Hapludolls (Marshall

and Monona series) formed on loess-mantled uplands. Well

drained, strongly sloping Alfisols (Knox series) formed in loess.

Well drained, strongly sloping Udorthents on side slopes

(Steinauer series) and Argiudolls (Shelby series) formed in clay

loam glacial till. Somewhat excessively drained and well

drained, strongly sloping to very steep Udorthents (Hamburg

and Ida series) on uplands formed in thick layers of loess

bordering the Missouri River. Well drained and moderately well

drained Udifluvents (Haynie and McPaul series) and

Hapludolls (Keg, Kennebec, Napier, and Salix series),

somewhat poorly drained or poorly drained Fluvaquents

(Onawa and Albaton series), and poorly drained or very poorly

drained Haplaquolls (Colo, Luton, and Wabash series) formed

in alluvium on bottom land.

Biological Resources

Prairies in this area support tall grasses on moist soils and

xeric short grasses on uplands. Within the prairies, grama,

muhly, lovegrass, and wheatgrass commonly grow beside the

more familiar little bluestem, big bluestem, Indiangrass, and

wildrye. The most common forbs are eared milkweed, Missouri

milkvetch, prairie tea, western prairie fringed orchid, yucca,

Baldwin ironweed, painted cup, pale gentian, silky aster, and

skeletonweed (in the loess hills).

The wooded areas on uplands commonly support red oak,

white oak, hackberry, shagbark hickory, and bitternut hickory.

The wooded areas on bottom land commonly support mulberry,

Climate

The average annual precipitation in this area is 26 to 41

inches (660 to 1,040 millimeters). Most of the rainfall occurs as

convective thunderstorms during the growing season. About 10

percent of the precipitation occurs as snow in the winter. The

average annual temperature is 46 to 56 degrees F (8 to 13

degrees C). The freeze-free period averages about 190 days and

ranges from 155 to 220 days.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 5.1%; ground water, 1.8%

Livestock—surface water, 0.2%; ground water, 0.4%

Irrigation—surface water, 0.4%; ground water, 1.7%

Other—surface water, 89.1%; ground water, 1.3%

The total withdrawals average 4,210 million gallons per day

(15,935 million liters per day). About 5 percent is from ground

water sources, and 95 percent is from surface water sources.

Sediment, nutrients, and pesticides from agricultural activities

impair many of the major streams and rivers in this area (not

including the Missouri River). The surface water is used mainly

for cooling thermoelectric power plants along the Missouri

River. The Missouri River also provides most of the municipal

and industrial water for the major cities in the area. Other

streams and rivers provide some surface water for livestock,

irrigation, and public supplies in parts of the area.

The principal sources of ground water in the area are glacial

drift, alluvial aquifers along the major streams, buried valley

aquifers, the Dakota Sandstone, and Paleozoic rocks. Glacial

drift aquifers supply many rural homeowners with domestic

water. The buried channels are sources of moderate or

moderately large supplies of generally good-quality water. The

mineral content of the water may be high if this aquifer is

hydraulically connected to bedrock aquifers beneath it.

Alluvial deposits are extensive across the broad flood plain

along the Missouri River. This aquifer is used for public

supplies in Missouri. It has very hard water that contains a

median level of 467 parts per million (milligrams per liter) total

dissolved solids. The other shallow aquifers in Iowa have water

very similar in quality to that in the Missouri River alluvium.

They provide water for domestic use, livestock, some irrigation,

and public supply.

The Cretaceous-age Dakota Sandstone is at a shallow or

moderate depth in the northern half of this area. It is tapped by

many domestic and livestock wells. A few irrigation wells tap

this aquifer. In areas where more shallow aquifers do not occur,

a number of communities obtain their public supplies from this

aquifer. Locally, the base of the Dakota Sandstone has beds of

gravel from which moderately large yields can be obtained. The

median level of total dissolved solids in the aquifer in Iowa and
334 Major Land Resource Areas

108A—Illinois and Iowa Deep Loess and

Drift, Eastern Part

This area (shown in fig. 108A-1) is in Illinois (97 percent)

and Indiana (3 percent). It makes up about 11,145 square miles

(28,875 square kilometers). The cities of Decatur, Champaign,

sycamore, cottonwood, willow, elms, green ash, silver maple,

and American elder.

The wildlife species in the prairies include barn and longeared owls; broad-winged hawk; Leonard’s, Pawnee, Ottoe, and

dusted skippers; wild indigo and sleepy dusky wings; and zebra

swallowtail, Great Plains toad, plains leopard frog, plains

spadefoot, massasauga rattlesnake, prairie skink, ornate box

turtle, six lined racerunner, bobcat, black-tailed jackrabbit,

plains pocket mouse, and least shrew. The wildlife species in

the wooded areas include blue grosbeak, great crested

flycatcher, western meadowlark, western fox snake, western

worm snake, and Woodhouse’s toad. This area has 47

threatened or endangered species or species of special concern,

including piping plover, blacknose and Topeka shiners, pallid

sturgeon, least tern, small white lady’s slipper, bog buckbean,

yellow monkey flower, and spring ladies-tresses.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 69%

Grassland—private, 11%; Federal, 1%

Forest—private, 7%

Urban development—private, 8%

Water—private, 2%

Other—private, 2%

Historically, 92 percent of this MLRA was prairie. Forests

made up 4 percent of the area; savannas, 2 percent; rivers and

streams, 1 percent; wetlands, 1 percent; ponds and lakes, 0.2

percent; and shrub land, 0.2 percent. The increase in the

forested acreage from 4 percent of the historic landscape to 7

percent of the current landscape occurred mainly on the loess

hills, where the forested acreage increased significantly because

of fire suppression.

Farms currently make up nearly all of this area. They

produce cash and grain crops and livestock.

The major resource concerns are water erosion, depletion of

organic matter in the soils, and poor water quality.

Conservation practices on cropland generally include systems

of crop residue management (especially no-till, strip-till, and

mulch-till systems), cover crops, pest and nutrient management,

grassed waterways, terraces, manure management, pasture and

hayland planting, and grade-stabilization structures. 

Figure 108A-1: Location of MLRA 108A in Land Resource Region M.

Urbana, Bloomington, and De Kalb, Illinois, are in this MLRA.

Interstates 39, 55, and 57 cross the area, running north and

south. Interstate 72 crosses the area from Champaign, through

Decatur, and on to Springfield, Illinois. Interstate 74 connects

Champaign-Urbana and Bloomington, and Interstate 80 crosses

the northern end of the area. The numerous State parks in the

MLRA include Moraine Hills in the northern part of the area

and Moraine View in the southern part. The National

Accelerator Laboratory and Chanute Air Force Base are Federal

installations in the MLRA.

Physiography

Almost all of this area is on the glaciated Bloomington

Ridged Plain in the Till Plains Section of the Central Lowland

Province of the Interior Plains. The northern tip is in the Eastern

Lake Section of the same province and division. The area is a

relatively young, moderately dissected, rolling plain with

stream terraces adjacent to the broad flood plains along the

major streams and rivers. Glacial moraines are numerous in the

area and tend to form elongated ridges tending from northwest

to southeast. Slopes are generally less than 5 percent but are

significantly steeper on the moraines and along the major

streams. Elevation ranges from 660 feet (200 meters) in the

southern part of the area to about 985 feet (300 meters) in the

northern part. The maximum local relief is about 160 feet (50

meters) along the major streams. Relief is considerably lower,
of the United States 335

The principal sources of ground water in the area are glacial

drift, the Sand-and-Gravel aquifer, alluvial aquifers along the

major streams, and Paleozoic bedrock. Glacial drift aquifers

supply many rural homeowners with domestic water, but this

water typically has high levels of iron. The iron is not

dangerous to public health, but it causes esthetic problems of

iron stains and scale. Alluvial deposits provide water for

domestic use and livestock. The water in these deposits is

similar in quality to the surface water and is suitable for most

uses. The shallow Sand-and-Gravel aquifer is extensive

throughout Illinois. It typically consists of glacial outwash

deposits within the drift. The water in this aquifer is very hard

and may have very high levels of iron. The median level of

total dissolved solids is very near the national secondary

drinking water standard of 500 parts per million (milligrams per

liter). This aquifer provides water for domestic use, livestock,

irrigation, and public and municipal supply.

Paleozoic bedrock aquifers are not utilized very much in this

area. The Pennsylvanian-Mississippian aquifer underlies the

lower three-fourths of the area. Well yields from this aquifer are

generally low, so the aquifer is not used extensively. The water

is extremely variable in quality. It is generally more heavily

mineralized than the water in the surficial aquifers, and it has

high levels of iron. The Shallow Dolomite aquifer occurs only

in the extreme northern part of this area. The water in this

aquifer is similar in quality to the water in the PennsylvanianMississippian aquifer and is not used unless no other aquifer is

available. The Cambrian-Ordovician aquifer underlies the

northern quarter of this MLRA. This aquifer is used extensively

in the northern third of Illinois. Its water is of good quality and

is suitable for almost all uses. Wells can penetrate the St. Peter

Sandstone in the upper part of this unit or the deeper IrontonGalesville layer. The median level of total dissolved solids is

typically less than the national secondary drinking water

standard of 500 parts per million (milligrams per liter), and iron

levels are much lower than those in the water from the other

bedrock aquifers.

Soils

The dominant soil orders in this MLRA are Mollisols and

Alfisols. Most of the soils are Udolls or Aquolls. The soils in the

area have a mesic soil temperature regime, an aquic or udic soil

moisture regime, and dominantly mixed mineralogy. They

generally are moderately deep to very deep, poorly drained to

moderately well drained, and silty or clayey. Nearly level

Endoaquolls (Drummer series) and gently sloping to sloping

Argiudolls (Saybrook and Catlin series) formed in loess over

loamy till on uplands. Hapludalfs commonly occur along the

major stream valleys. They are on the gently sloping to

moderately sloping uplands (Birkbeck and Mayville series) or

on the steep or very steep valley bluffs (Strawn series).

however, in most of the area. It typically is only 3 to 10 feet (1

to 3 meters) on the broad, flat uplands.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Lower Illinois (0713), 46 percent; Wabash (0512), 26 percent;

Upper Illinois (0712), 13 percent; Upper MississippiKaskaskia-Meramec (0714), 10 percent; and Rock (0709), 5

percent. The Illinois, Rock, and Wabash Rivers drain this

MLRA.

Geology

This area is underlain by Pennsylvanian shale, siltstone, and

limestone in the southern part and Ordovician and Silurian

limestone in the extreme northern part. Glacial drift covers all

of the MLRA, except for some areas along the major streams

where the underlying bedrock is exposed. The glacial drift is

Wisconsin in age and consists of distinct till units as well as

sorted, stratified outwash. The entire area has been covered by a

moderately thin or thick layer of loess. In a few areas the loess

directly overlies the bedrock.

Climate

The average annual precipitation in this area is 35 to 43

inches (890 to 1,090 millimeters). Two-thirds or more of the

precipitation falls as convective thunderstorms during the

freeze-free period. In winter, precipitation is low and occurs

mostly as snow. The average annual temperature is 47 to 54

degrees F (8 to 12 degrees C). The freeze-free period averages

about 195 days and ranges from 175 to 210 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 50.0%; ground water, 15.9%

Livestock—surface water, 0.1%; ground water, 6.8%

Irrigation—surface water, 0.0%; ground water, 3.9%

Other—surface water, 19.3%; ground water, 3.9%

The total withdrawals average 260 million gallons per day

(985 million liters per day). About 31 percent is from ground

water sources, and 69 percent is from surface water sources. In

most years lack of moisture is not a problem for agricultural

production. Numerous large rivers provide surface water for

livestock, irrigation, industry, and public supplies in the area.

Some water for livestock is stored in small ponds and reservoirs.

The surface water is of fair or good quality and is suitable for

most uses. Sediment, nutrients, and pesticides from agricultural

activities and wastewater discharges from cities can

contaminate the surface water in the area.
336 Major Land Resource Areas

108B—Illinois and Iowa Deep Loess and

Drift, East-Central Part

This area is entirely in Illinois (fig. 108B-1). It makes up

about 7,450 square miles (19,300 square kilometers). It is in

two parts separated by MLRA 115C (Central Mississippi Valley

Wooded Slopes, Northern Part). Two-thirds of the area is in

northwestern Illinois, and one-third is in central Illinois. The

towns of Kewanee and Galesburg are in the western part of the

area, and the towns of Macomb, Jacksonville, and Springfield

are in the eastern part. Interstates 74, 80, and 88 cross the

northern part of the area.

Physiography

This area is in the Till Plains Section of the Central Lowland

Province of the Interior Plains. The eastern part of the area, on

the east side of the Illinois River, is on the glaciated Springfield

Plain. The western part is dominantly on the Galesburg Plain.

The northern part of this western area also encompasses the

Green River Lowland and the Rock River Hill Country. The

entire MLRA was glaciated and has deposits of loess of various

thickness. The area is on a relatively young, moderately

dissected to strongly dissected, rolling plain where stream

terraces are adjacent to broad flood plains along the major

Argiudolls (Plano and Warsaw series) and Hapludalfs (St.

Charles and Fox series) are on gently sloping to sloping stream

terraces along the major streams and on broad outwash plains.

Cumulic Endoaquolls (Sawmill series) and Cumulic Hapludolls

(Lawson and Huntsville series) formed in alluvium on nearly

level, broad flood plains and in the smaller upland

drainageways.

Biological Resources

This area originally supported prairie vegetation with

hardwood forests on scattered upland sites. The areas of tall

prairie grasses are characterized by big bluestem, Indiangrass,

prairie dropseed, and switchgrass. White oak, shingle oak,

black oak, hickory, white ash, basswood, sugar maple, and

walnut grow on the better drained soils. Silver maple, black

willow, cottonwood, and sycamore grow on flood plains.

Some of the major wildlife species in this area are whitetailed deer, coyote, turkey, red fox, beaver, raccoon, skunk,

muskrat, opossum, cottontail rabbit, fox squirrel, Canada goose,

red-tailed hawk, great horned owl, blue heron, wood duck,

mallard duck, redheaded woodpecker, and ring-necked

pheasant. Fishing is limited mostly to constructed

impoundments and rivers. The species of fish in the area

include largemouth bass, carp, catfish, bluegill, crappie, and

sunfish.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 80%

Grassland—private, 3%; Federal, 1%

Forest—private, 5%

Urban development—private, 8%

Water—private, 1%

Other—private, 2%

Most of this area is in privately owned farms, which produce

mainly cash-grain crops and livestock. About 80 percent of the

area is cropland, and nearly 5 percent supports introduced and

native grasses. The less sloping soils are used for dry-farmed

corn for grain and silage and for soybeans. Some small grains,

such as winter wheat, also are grown in the area. A few areas on

broad outwash plains are irrigated and are used primarily for

high-value specialty crops. The forested areas in this MLRA are

mainly along the major streams.

The major resource concerns are wind erosion, water erosion,

and maintenance of the content of organic matter and

productivity of the soils. Conservation practices on cropland

generally include systems of crop residue management

(especially no-till systems), cover crops, windbreaks, vegetative

wind barriers, and nutrient management. 

Figure 108B-1: Location of MLRA 108B in Land Resource Region M.
of the United States 337

production. Numerous large rivers provide surface water for

livestock, irrigation, industry, and public supplies in this area.

Water-supply reservoirs are common in the eastern part of the

area. Some water for livestock is stored in small ponds and

reservoirs. The surface water is of fair or good quality and is

suitable for most uses. Sediment, nutrients, and pesticides from

agricultural activities and wastewater discharges from cities can

contaminate the water.

The principal sources of ground water in this area are glacial

drift, the Sand-and-Gravel aquifer, alluvial aquifers along the

major streams, and Paleozoic bedrock. Glacial drift aquifers

supply many rural homeowners with domestic water that has

high levels of iron. The iron is not dangerous to public health,

but it causes esthetic problems of iron stains and scale. Alluvial

deposits provide water for domestic use and livestock. The

water in these deposits is similar in quality to the surface water

and is suitable for most uses. The shallow Sand-and-Gravel

aquifer is extensive throughout the State. It typically consists

of glacial outwash deposits within the drift. Water in this

aquifer is very hard and may have very high levels of iron. The

median level of total dissolved solids is very near the national

secondary drinking water standard of 500 parts per million

(milligrams per liter). This aquifer provides water for domestic

use, livestock, irrigation, and public and municipal supply.

Paleozoic bedrock aquifers are not utilized very much in this

area. The Pennsylvanian-Mississippian aquifer underlies all of

the eastern part of the area and the southern two-thirds of the

western part. Well yields from this aquifer are generally low, so

the aquifer is not used extensively. The water in this aquifer is

extremely variable in quality. It is generally more heavily

mineralized than the water in the surficial aquifers, and it has

high levels of iron. The Shallow Dolomite aquifer occurs only

in the northern one-third of the western part of this area. Its

water is similar in quality to the water in the PennsylvanianMississippian aquifer, and it is not used unless no other aquifer

is available. The Cambrian-Ordovician aquifer occurs only

north of the Shallow Dolomite aquifer in the western part of this

MLRA. This aquifer is used extensively in the northern third of

Illinois. Its water is of good quality and is suitable for almost all

uses. Wells can penetrate the St. Peter Sandstone in the upper

part of this unit or the deeper Ironton-Galesville layer. The

median level of total dissolved solids is typically less than the

national secondary drinking water standard of 500 parts per

million (milligrams per liter), and iron levels are much lower

than those in the water from the other bedrock aquifers.

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, Inceptisols, and Mollisols. Most of the soils are

Udolls or Udalfs. Aquolls are in the flatter interfluve areas. The

soils in the area have a mesic soil temperature regime, an aquic

or udic soil moisture regime, and dominantly mixed

mineralogy. They generally are moderately deep to very deep,

streams and rivers. Slopes are generally less than 15 percent but

are significantly steeper in some areas along the major streams.

Elevation ranges from 660 feet (200 meters) in the eastern and

southern parts of the area to about 985 feet (300 meters) in the

western and northern parts. The maximum local relief is about

160 feet (50 meters) along the major streams and along the

dissected drainageways fingering into the uplands. Relief is

considerably lower in much of the area. It typically is only 3 to

10 feet (1 to 3 meters) on the broad, flat uplands.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Lower Illinois (0713), 42 percent; Rock (0709), 35 percent;

Upper Mississippi-Iowa-Skunk-Wapsipinicon (0708), 22

percent; and Upper Mississippi-Maquoketa-Plum (0706), 1

percent. The Illinois, Rock, and Mississippi Rivers drain the

MLRA.

Geology

This area is underlain by Pennsylvanian shales, siltstones,

and limestones in the southern and western parts and

Ordovician and Silurian limestone in the extreme northern part.

Coal beds occur in the northern part and east of the Illinois

River. Glacial drift covers the entire area, except for the bluffs

along the major streams, where the underlying bedrock can be

exposed. The glacial till is Illinoian in age and consists of

distinct till units as well as sorted, stratified outwash of

Wisconsin age. The entire area has been covered by a thick or

moderately thin layer of Wisconsin loess. In a few areas the

loess directly overlies the bedrock.

Climate

The average annual precipitation in this area is 33 to 39

inches (840 to 990 millimeters). Two-thirds or more of the

precipitation occurs as convective thunderstorms during the

growing season. In winter, precipitation is low and occurs

mostly as snow. The average annual temperature is 47 to 54

degrees F (8 to 12 degrees C). The freeze-free period averages

about 185 days and ranges from 165 to 210 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 46.8%; ground water, 16.5%

Livestock—surface water, 0.1%; ground water, 4.1%

Irrigation—surface water, 0.5%; ground water, 7.2%

Other—surface water, 20.6%; ground water, 4.2%

The total withdrawals average 240 million gallons per day

(910 million liters per day). About 32 percent is from ground

water sources, and 68 percent is from surface water sources. In

most years lack of moisture is not a problem for agricultural
338 Major Land Resource Areas

somewhat poorly drained to well drained, and silty or clayey.

Nearly level Endoaquolls (Sable series) and depressional to

nearly level Albaqualfs (Rushville and Denny series) occur on

broad interfluves. Gently sloping to sloping Argiudolls (Tama

and Ipava series) formed in thick deposits of loess on uplands.

Some Hapludalfs (Fayette, Elco, and Hickory series) formed in

loess that is deep to loamy till or a paleosol. They are along the

major streams and in dissected upland drainageways. Other

Hapludalfs (Marseilles series) formed in loess and bedrock

residuum in major stream valleys. Argiudolls (Plano and

Warsaw series) and Hapludalfs (St. Charles and Fox series) are

on gently sloping to sloping terraces along the major streams.

Endoaquolls (Sawmill and Otter series) and Hapludolls

(Lawson, Huntsville, and Ross series) formed in alluvium on

nearly level, broad flood plains. Fluvaquents (Wakeland series)

and Udifluvents (Orion series) are along the much smaller

upland drainageways.

Biological Resources

This area originally supported prairie vegetation with

hardwood forests on scattered upland sites. The areas of tall

prairie grasses are characterized by big bluestem, Indiangrass,

prairie dropseed, and switchgrass. White oak, shingle oak,

black oak, hickory, white ash, basswood, sugar maple, and

walnut grow on the better drained soils. Silver maple, black

willow, cottonwood, and sycamore grow on flood plains.

Some of the major wildlife species in this area are whitetailed deer, coyote, turkey, red fox, beaver, raccoon, skunk,

muskrat, opossum, cottontail rabbit, fox squirrel, Canada goose,

red-tailed hawk, great horned owl, blue heron, wood duck,

mallard duck, redheaded woodpecker, and quail. Fishing is

limited mostly to constructed impoundments and rivers. The

species of fish in the area include largemouth bass, carp, catfish,

bluegill, crappie, and sunfish.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 79%

Grassland—private, 7%

Forest—private, 5%

Urban development—private, 6%

Water—private, 1%

Other—private, 2%

Most of this area is in privately owned farms. Almost 80

percent of the area is cropland. Cash-grain crops are dominant,

but hay and pasture crops also are grown for the livestock

produced in the area. The less sloping soils are used for dryfarmed corn for grain and silage and for soybeans. Some small

grains, such as winter wheat and oats, are also grown in the area.

A few areas on broad stream terraces and outwash plains are

irrigated. About 7 percent of the area supports introduced and

native grasses. Although not occupying an overall large

acreage, surface-mined areas that have been or are being

reclaimed occur in the northern part of the MLRA and active

underground coal-mining areas occur in the part of the MLRA

on the east side of the Illinois River.

The major resource concerns are wind erosion, water erosion,

and maintenance of the content of organic matter and

productivity of the soils. Conservation practices on cropland

generally include systems of crop residue management

(especially no-till systems), cover crops, windbreaks, vegetative

wind barriers, and nutrient management. 

108C—Illinois and Iowa Deep Loess and

Drift, West-Central Part

This area is entirely in Iowa (fig. 108C-1). It makes up about

9,805 square miles (25,405 square kilometers). The towns of

Newton, Oskaloosa, Pella, Marshalltown, Iowa City, and

Washington are in this MLRA. Interstate 80 crosses the center

of the MLRA from east to west. This area includes many State

parks and the Sac and Fox and Mesquakie Indian Reservations.

Physiography

This area is in the Dissected Till Plains Section of the

Central Lowland Province of the Interior Plains. Locally, it is

within a landform region called the Southern Iowa Drift Plain.

As the section name implies, this area is a dissected till plain.

Slopes are mostly rolling to hilly, but some broad ridgetops are

nearly level to undulating and areas bordering the major stream

valleys are steep. A few large rivers have nearly level, broad

valley floors. Elevation ranges from 505 feet (155 meters) in the

lowest valleys to 1,110 feet (340 meters) on the highest ridges.

Local relief is mainly 10 to 20 feet (3 to 6 meters), but valley

floors can be 80 to 200 feet (25 to 60 meters) below the

adjacent uplands. Also, some upland flats and valley floors

have local relief of only 3 to 6 feet (1 to 2 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Upper Mississippi-Iowa-Skunk-Wapsipinicon (0708), 95

percent, and Des Moines (0710), 5 percent. The Des Moines,

Skunk, Iowa, and Cedar Rivers cross this area. These watersheds

have more than 10,600 miles of streams and associated

wetlands that drain to the Mississippi River.

Geology

This area is underlain by dense pre-Illinoian till, which was

deposited more than 500,000 years ago and has since

undergone extensive erosion and dissection. The till surface is

covered by a mantle of Peoria Loess on the hillslopes and by
of the United States 339

Figure 108C-1: Location of MLRA 108C in Land Resource Region M.

Holocene alluvium (DeForest Formation) in the drainageways.

The till is generally less than 150 feet (45 meters) thick in the

southern half of the area but ranges from 150 to 350 feet (45 to

105 meters) in thickness in the northern half. It is underlain by

Paleozoic bedrock consisting dominantly of limestone, shale,

and mudstones. The bedrock includes dolomite in the

northeastern part of the area.

Climate

The average annual precipitation in this area is 33 to 38

inches (840 to 965 millimeters). Most of the rainfall occurs as

convective thunderstorms during the growing season. About 10

inches (25 centimeters) of the precipitation occurs as snow in

the winter. The average annual temperature is 46 to 51 degrees

F (8 to 11 degrees C). The freeze-free period averages about 185

days and ranges from 170 to 205 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 4.8%; ground water, 45.3%

Livestock—surface water, 4.2%; ground water, 17.1%

Irrigation—surface water, 0.0%; ground water, 0.5%

Other—surface water, 1.1%; ground water, 27.0%

The total withdrawals average 90 million gallons per day

(340 million liters per day). About 90 percent is from ground

water sources, and 10 percent is from surface water sources. In

most years lack of water is not a problem for agricultural

production. Large rivers provide some surface water for

livestock, irrigation, industry, and public supplies. The

Coralville Reservoir provides municipal and industrial water to

areas along the Iowa River. Some water for livestock is stored in

small ponds and reservoirs. The surface water is of fair quality

and is suitable for most uses with treatment. Contamination

from sediment, nutrients, and pesticides from agricultural

activities and wastewater discharges from cities cause some

water-quality problems.

Good-quality ground water is abundant in this area. The

principal sources of ground water in the area are glacial drift

aquifers, buried channel aquifers, alluvial aquifers, and

Paleozoic bedrock. Glacial drift aquifers supply many rural

homeowners with small quantities of domestic water and some

livestock water. Alluvial deposits provide much greater

quantities of water for domestic use, livestock, public supply,

and some limited irrigation. Buried channels typically consist

of glacial outwash deposits that filled preglacial valleys and

then were covered by glacial drift. Large quantities of water can

be obtained from this aquifer in the limited areas where it

occurs. This aquifer can provide water for domestic use,

livestock, irrigation, and some public and municipal supply. All

of these surficial aquifers have good-quality water. The water is

very hard, but the median level of total dissolved solids is very

near the national secondary drinking water standard of 500

parts per million (milligrams per liter).

Paleozoic bedrock aquifers are heavily utilized in this area.

The Silurian-Devonian aquifer underlies the northern half of the

area, the Mississippian aquifer underlies the southern half, and

the Jordan aquifer underlies all of the area. The Jordan aquifer

is the most extensively used aquifer in Iowa. It consists of

sandstone and dolomite of Ordovician and Cambrian age. Well

yields from this aquifer are very high. The water from this

aquifer is suitable for most uses, but the median level of total

dissolved solids typically exceeds 800 parts per million

(milligrams per liter) and radium-226 levels can exceed the

national standard for drinking water. The Silurian-Devonian

aquifer consists of limestone and dolomite. It is close to the

surface in this area, and it has the best water quality of all the

principal aquifers in Iowa. Where this aquifer is buried by

younger bedrock deposits, its use is limited by the level of total

dissolved solids and naturally high levels of sulfate. The

Mississippian aquifer consists of limestone and dolomite that is

very close to the surface in this area. Its water quality is

between that of the other two bedrock aquifers. In some areas it

has very high levels of total dissolved solids and thus cannot

be used. Wells in this aquifer produce low yields, so the aquifer

is not used unless no other water sources are available. Water

from the Jordan and Silurian-Devonian aquifers is used for
340 Major Land Resource Areas

domestic purposes, livestock, irrigation, public and municipal

supply, and industry.

Soils

The dominant soil orders in this MLRA are Mollisols and, to

a lesser extent, Alfisols, Entisols, and Inceptisols. Most of the

soils are Udolls or Udalfs. Some Aquolls are on the flatter

interfluves and on nearly level, broad valley floors. The soils in

the area dominantly have a mesic soil temperature regime, an

aquic or udic soil moisture regime, and mixed mineralogy.

They generally are very deep, well drained to poorly drained,

and silty, loamy, or clayey. The soils on uplands include

somewhat poorly drained, nearly level Argiudolls (Mahaska

series) and Hapludolls (Muscatine series); moderately well

drained, gently sloping to strongly sloping Argiudolls (Otley

series); well drained or moderately well drained, moderately

sloping to strongly sloping Eutrudepts (Killduff series); poorly

drained, nearly level Endoaquolls (Garwin series) and

Argiaquolls (Taintor series); well drained or moderately well

drained, gently sloping to strongly sloping Argiudolls (Tama

and Dinsdale series); and well drained, strongly sloping to steep

Hapludalfs (Fayette, Downs, Ladoga, Armstrong, and Clinton

series). Somewhat poorly drained Hapludolls (Lawson series)

and moderately well drained Udifluvents (Nodaway series)

formed in silty alluvium on flood plains. Poorly drained

Endoaquolls (Colo and Zook series) formed in clayey alluvium

on flood plains.

Biological Resources

Prairies in this area are dominated by tall grasses. Xeric mid

and short grasses occur on steep slopes, ridges, and sandy soils.

Grama, muhly, lovegrass, dropseed, wild rice, threeawn, and

wheatgrass may occur in the prairies, along with the dominant

bluestems, Indiangrass, switchgrass, prairie cordgrass, and

wildrye. The forbs in the area include pale and round-stemmed

false foxgloves, Virginia snakeroot, golden corydalis,

kittentails, shooting star, foxglove penstemon, cleft phlox,

eastern and western prairie fringed orchid, blackeyed Susan,

sneezeweed, puccoon, wild geranium, slender mountain mint,

and bottle gentian. Wooded areas on uplands commonly

support red oak, white oak, hackberry, and shagbark,

mockernut, butternut, and bitternut hickories. Wooded areas on

bottom land commonly support swamp white oak, pin oak,

river birch, sycamore, cottonwood, willow, redbud, white ash,

green ash, silver maple, and American elder.

The wildlife species on the prairies in this area include

plains leopard frog, tiger salamander, ornate box turtle, sixlined racerunner, slender glass lizard, smooth green snake, bull

snake, western hognose, prairie king snake, massasauga

rattlesnake, long-eared owl, northern harrier, wild indigo dusky

wing, Baltimore checkerspot, regal fritillary, plains pocket

mouse, spotted skunk, and bald eagle. The wildlife species in

the wooded areas include the great-crested flycatcher,

prothonitary warbler, ovenbird, Acadian flycatcher, scarlet

tanager, Indiana bat, western fox snake, western worm snake,

and Fowler’s toad. This MLRA has 91 threatened or endangered

species or species of special concern. The watersheds in the area

provide habitat for many rare and declining species, such as the

least tern, piping plover, lake sturgeon, pirate perch, blacknose

and Topeka shiners, pallid sturgeon, grass pickerel, bluntnose

darter, pugnose minnow, freckled madtom, sheepnose, round

pigtoe, spectacle case, yellow sandshell, strange floater, pistol

grip, central newt, Blanding’s turtle, yellow mud turtle, and

common musk turtle.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 76%

Grassland—private, 9%; Federal, 1%

Forest—private, 6%

Urban development—private, 5%

Water—private, 1%

Other—private, 2%

In the mid-1800s, about 75 percent of this area was prairie.

Forests made up 18.5 percent of the area; savannas, 5 percent;

shrub lands, 1 percent; wetlands, 0.4 percent; and streams, 0.1

percent.

Farms currently make up nearly all of this area. They

produce cash crops, grain crops, and livestock.

The major resource concerns are water erosion, depletion of

organic matter in the soils, and poor water quality.

Conservation practices on cropland generally include systems

of crop residue management (especially no-till, strip-till, and

mulch-till systems), cover crops, pest and nutrient management,

grassed waterways, terraces, manure management, pasture and

hayland planting, and grade-stabilization structures. 

108D—Illinois and Iowa Deep Loess and

Drift, Western Part

This area (shown in fig. 108D-1) is in Iowa (82 percent) and

Missouri (18 percent). It makes up about 5,480 square miles

(14,195 square kilometers). It includes the towns of Clarinda,

Creston, and Indianola, Iowa; the southern part of the city of

Des Moines, Iowa; and the town of Maryville, Missouri.

Interstate 35 crosses the eastern part of the area from north to

south, and Interstate 80 crosses the northern end of the area.

Physiography

This area is in the Dissected Till Plains Section of the

Central Lowland Province of the Interior Plains. The area is in a
of the United States 341

Figure 108D-1: Location of MLRA 108D in Land Resource Region M.

landform region locally called the Southern Iowa Drift Plain.

Slopes are mostly rolling to hilly, but some broad ridgetops are

nearly level to undulating and areas bordering the major stream

valleys are steep. Nearly level, broad valley floors are along a

few large rivers. Elevation ranges from 690 feet (210 meters) in

the lowest valleys to 1,510 feet (460 meters) on the highest

ridges. Local relief is mainly 10 to 20 feet (3 to 6 meters), but

valley floors can be 80 to 200 feet (25 to 60 meters) below the

adjacent uplands. Also, some upland flats and valley floors

have local relief of only 3 to 6 feet (1 to 2 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Missouri-Nishnabotna (1024), 54 percent; Des Moines (0710),

37 percent; and Chariton-Grand (1028), 9 percent. The

Raccoon and Des Moines Rivers empty into the Mississippi

River to the southeast of this area, and the Platte and Nodaway

Rivers empty into the Missouri River to the southwest of the

area. The Tarkio-Wolf, West Nodaway, Nodaway, One-Hundred

and Two, and Platte watersheds and parts of the Lake Red Rock

and Thompson watersheds have more than 6,700 miles of

streams and associated wetlands in this area.

Geology

This MLRA is underlain by dense pre-Illinoian till, which

was deposited more than 500,000 years ago and has since

undergone extensive erosion and dissection. A mantle of silt

(Peoria Loess) covers the till surface on the hillslopes, and

Holocene alluvium (DeForest Formation) is typically in stream

valleys. The till is generally less than 150 feet (45 meters) thick

in the northern and southwestern parts of the area and ranges

from 150 to 350 feet (45 to 105 meters) in thickness in the rest

of the area. It is underlain mainly by Pennsylvanian bedrock

consisting dominantly of shale and mudstones.

Climate

The average annual precipitation in this area is 33 to 37

inches (840 to 940 millimeters). Most of the rainfall occurs as

convective thunderstorms during the growing season. About 10

inches (25 centimeters) of the precipitation occurs as snow in

the winter. The average annual temperature is 48 to 52 degrees

F (9 to 11 degrees C). The freeze-free period averages about 185

days and ranges from 175 to 200 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 13.1%; ground water, 15.6%

Livestock—surface water, 2.4%; ground water, 10.3%

Irrigation—surface water, 0.1%; ground water, 0.0%

Other—surface water, 53.0%; ground water, 5.5%

The total withdrawals average 71 million gallons per day

(270 million liters per day). About 31 percent is from ground

water sources, and 69 percent is from surface water sources. In

most years lack of moisture is not a problem for agricultural

production. Large rivers provide surface water for livestock,

industry, and public supplies in the area. Some water for

livestock is stored in small ponds and reservoirs. The surface

water is of fair quality and is suitable for most uses with

treatment. Contamination from sediment, nutrients, and

pesticides from agricultural activities and wastewater

discharges from cities cause some water-quality problems.

The principal sources of ground water in the area are glacial

drift aquifers, buried channel aquifers, and alluvial aquifers.

Glacial drift aquifers supply many rural homeowners with small

quantities of domestic water and some livestock water. Alluvial

deposits provide much greater quantities of water for domestic

use, livestock, and some public supply. Buried channels

typically consist of glacial outwash deposits that filled

preglacial valleys and then were covered by glacial drift. Large

quantities of water can be obtained from this aquifer in the

limited areas where the aquifer occurs. This aquifer can provide

water for domestic use, livestock, and some public and

municipal supply. All of these surficial aquifers have goodquality water. The water is very hard, but the median level of

total dissolved solids is very near the national secondary

drinking water standard of 500 parts per million (milligrams per

liter).
342 Major Land Resource Areas

Paleozoic bedrock aquifers are not utilized very much in this

area. The Dakota aquifer underlies the northwestern part of the

area, and the Jordan aquifer underlies all of the area. The Jordan

aquifer is the most extensively used aquifer in Iowa. It consists

of sandstone and dolomite of Ordovician and Cambrian age.

Well yields from this aquifer are very high, and the water is

suitable for most uses. The median level of total dissolved

solids, however, typically exceeds 800 parts per million

(milligrams per liter), and radium-226 levels can exceed the

national standard for drinking water. The Dakota aquifer

consists of Cretaceous-age sandstone. It is close to the surface

in this area, and its water is very similar in quality to the water

in the Jordan aquifer. Some communities and rural

homeowners utilize these bedrock aquifers for drinking water

where no other aquifers are available. The water from the

Jordan and Dakota aquifers is used for domestic purposes,

livestock, and some public and municipal supply and

industry.

Soils

The dominant soil orders in this MLRA are Mollisols and

Alfisols and, to a lesser extent, Entisols. Most of the soils are

Udolls or Udalfs. Aquolls are on the flatter interfluves. The soils

in the area dominantly have a mesic soil temperature regime, an

aquic or udic soil moisture regime, and mixed mineralogy.

They generally are very deep, well drained to poorly drained,

and silty, loamy, or clayey. The soils on uplands include

somewhat poorly drained, nearly level Argiudolls (Macksburg

series); moderately well drained, gently sloping to strongly

sloping Argiudolls (Sharpsburg and Exira series); poorly

drained, nearly level Argiaquolls (Winterset and Taintor series);

and well drained, strongly sloping to steep Hapludalfs (Gara,

Lindley, Ladoga, Armstrong, Keswick, and Clinton series).

Somewhat poorly drained Hapludolls (Lawson series) and

moderately well drained Udifluvents (Nodaway series) formed

in silty alluvium on flood plains. Poorly drained Endoaquolls

(Colo and Zook series) formed in clayey alluvium on flood

plains.

Biological Resources

Prairies in this area support tall grasses on moist soils and

xeric short grasses on uplands. In the prairies, grama, muhly,

lovegrass, and bentgrasses commonly grow beside the more

familiar grasses, such as little bluestem, big bluestem,

Indiangrass, and wildrye. The forbs growing in the area include

Mead’s milkweed, fragrant false indigo, showy lady’s slipper,

western prairie fringed orchid, Virginia spiderwort, scaly

blazing star, Baldwin ironweed, and slender mountain mint.

Forests on uplands commonly support red oak, white oak,

bur oak, chinkapin oak, black oak, hackberry, shagbark hickory,

and bitternut hickory and may support some pawpaw. Forests

on bottom land support mulberry, sycamore, cottonwood,

willow, elm, white ash, silver maple, buttonbush, and American

elder.

The plains leopard frog, Henslow’s sparrow, northern harrier,

smooth green snake, spotted skunk, and massasauga rattlesnake

inhabit the prairies in this area. Brown snake, smallmouth

salamander, western worm snake, speckled king snake, and the

Indiana bat inhabit the forested areas. The area has 29

threatened or endangered species or species of special concern.

The watersheds are inhabited by many rare and declining

species, such as the Blanding’s turtle, Topeka shiner, small

white lady’s slipper, showy lady’s slipper, and glomerate sedge.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 66%

Grassland—private, 20%

Forest—private, 6%

Urban development—private, 4%

Water—private, 2%

Other—private, 2%

Historically, 86.75 percent of this area was prairie. Forest

made up 9 percent of the area; savannas, 4 percent; shrub lands,

0.2 percent; wetlands, 0.04 percent; and ponds and lakes, 0.01

percent.

Currently, about 86 percent of this area is agricultural land.

Cash-grain crops dominate the area, although hay and pasture

crops also are grown in support of local livestock production.

The major resource concerns are water erosion, depletion of

the organic matter in the soils, and poor water quality.

Conservation practices on cropland generally include systems

of crop residue management (especially no-till, strip-till, and

mulch-till systems), cover crops, nutrient and pest management,

grassed waterways, terraces, manure management, pasture and

hayland planting, and grade-stabilization structures. 

109—Iowa and Missouri Heavy Till Plain

This area (shown in fig. 109-1) is in Missouri (65 percent)

and Iowa (35 percent). It makes up about 15,895 square miles

(41,185 square kilometers). It includes the towns of Bethany,

Chillicothe, Memphis, and Plattsburg, Missouri, and Ottumwa,

Fairfield, Mt. Pleasant, and Centerville, Iowa. Interstate 35

crosses the northwestern part of this area.

Physiography

This area is in the Dissected Till Plains Section of the

Central Lowland Province of the Interior Plains. It is an area of

rolling hills interspersed with uniformly level upland divides

and level alluvial lowlands. Dendritic drainage patterns
of the United States 343

Figure 109-1: Location of MLRA 109 in Land Resource Region M.

characterize the area. The northeastern part of the area consists

of flat, tablelike uplands with steep or hilly land occurring only

near the margins of stream valleys. Other parts of the area are

more dissected, have less extensive upland divides, and consist

mostly of hillslopes. Nearly level, broad valley floors are along

a few large rivers. Elevation ranges from 660 feet (200 meters)

in the lowest valleys to 980 feet (300 meters) on the highest

ridges. Local relief is mainly 10 to 20 feet (3 to 6 meters), but

valley floors can be 80 to 160 feet (25 to 50 meters) below the

adjacent uplands. Also, some upland flats and valley floors

have local relief of only 3 to 6 feet (1 to 2 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Chariton-Grand (1028), 65 percent; Des Moines (0710), 14

percent; Upper Mississippi-Salt (0711), 9 percent; Lower

Missouri (1030), 5 percent; Upper Mississippi-Iowa-SkunkWapsipinicon (0708), 4 percent; and Missouri-Nishnabotna

(1024), 3 percent. The Grand, Thompson, and Chariton Rivers,

which are tributaries of the Missouri River, begin in the part of

this area in Iowa and flow south into Missouri. The Whitebreast

and Des Moines Rivers also occur in the northern part of the

area. The Locust River, in the southern part of the area, is

another major tributary of the Missouri River.

Geology

Loess covers the surface of almost all of the uplands in this

MLRA. Glacial drift that is high in content of clay underlies the

loess. Alluvial clay, silt, sand, and gravel deposits are in all of

the stream and river valleys. They can be extensive in the major

river valleys. Mississippian shale and limestone bedrock lies

beneath the glacial and alluvial deposits.

Climate

The average annual precipitation in most of this area is 34 to

41 inches (865 to 1,040 millimeters). About two-thirds of the

precipitation falls as high-intensity, convective thunderstorms

during the freeze-free period. The low amount of precipitation

in winter occurs as snow. The average annual temperature is 49

to 54 degrees F (9 to 12 degrees C). The freeze-free period

averages 190 days and ranges from 175 to 210 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 10.8%; ground water, 5.9%

Livestock—surface water, 3.9%; ground water, 4.3%

Irrigation—surface water, 0.0%; ground water, 1.5%

Other—surface water, 71.0%; ground water, 2.7%

The total withdrawals average 220 million gallons per day

(835 million liters per day). About 14 percent is from ground

water sources, and 86 percent is from surface water sources. In

most years the favorably distributed, moderate precipitation

provides enough water for crops. The many small perennial

streams and a few large streams are additional sources of water.

Since the ground water is highly mineralized, many

communities in the area rely on surface water for their supply of

drinking water. The streamflow fluctuates widely and

frequently, so storage is required to maintain any public

supplies.

Ground water supplies from glacial drift are small,

undependable, and of poor quality. This water is naturally high

in total dissolved solids, commonly exceeding the national

drinking water standard of 1,000 parts per million (milligrams

per liter). Some ground water is pumped for irrigation from

alluvial deposits along the larger rivers in the area.

Soils

The dominant soil orders in this MLRA are Alfisols and

Mollisols. The soils in the area dominantly have a mesic soil

temperature regime, an aquic or udic soil moisture regime, and

mixed or smectitic mineralogy. They generally are very deep,

well drained to poorly drained, and loamy or clayey. Hapludalfs

formed in loess and/or pedisediment over till (Armster,

Armstrong, and Keswick series), loess (Weller series), and till

(Gara and Lindley series) on uplands. Epiaqualfs (Pershing

series) and Argialbolls (Edina series) formed in loess on uplands

and benches. Argiaquolls (Clarinda series) formed in till on
344 Major Land Resource Areas

uplands. Argiudolls formed in loess (Grundy series), till

(Lamoni and Shelby series), and loess and/or pedisediment over

till (Lagonda series) on uplands. Endoaquolls (Zook series)

formed in alluvium on flood plains and stream terraces.

Biological Resources

This area supports grassland vegetation. Big bluestem,

Indiangrass, little bluestem, and switchgrass are the major

species. The natural drainageways and the lowlands

interspersed throughout the area support forest vegetation,

mainly oaks and hickories. Most of the native grasses have

been removed by cultivation and overgrazing. Naturalized

bluegrass is prevalent in uncultivated areas.

Some of the major wildlife species in this area are whitetailed deer, raccoon, skunk, opossum, muskrat, cottontail, mink,

squirrel, and quail. The species of fish in the area include

bullhead, carp, bass, bluegill, and catfish.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 53%

Grassland—private, 26%

Forest—private, 14%

Urban development—private, 3%

Water—private, 2%

Other—private, 2%

Nearly all of this area is in farms, and more than one-half is

cropland. Corn, soybeans, other feed grains, and hay are the

principal crops. About one-fourth of the area supports

introduced and native grasses. Beef cattle and swine are

important sources of income on many farms.

The major resource concerns are water erosion, depletion of

the organic matter in the soils, and poor water quality.

Conservation practices on cropland generally include systems

of crop residue management (especially no-till, strip-till, and

mulch-till systems), cover crops, pest management, nutrient

management, grassed waterways, terraces, manure management,

pasture and hayland planting, and grade-stabilization

structures. These practices help to control erosion, flooding,

and sedimentation. 

Figure 110-1: Location of MLRA 110 in Land Resource Region M.

110—Northern Illinois and Indiana

Heavy Till Plain

This area (shown in fig. 110-1) is in Illinois (79 percent),

Wisconsin (11 percent), and Indiana (10 percent). It makes up

about 7,535 square miles (19,525 square kilometers). The entire

northern part of this MLRA is an urban-suburban complex

including Milwaukee, Wisconsin, all of the western and

southern suburbs of Chicago, Illinois, and Merrillville, Indiana.

Pontiac and Kankakee, Illinois, are in the southern part of this

area. Danville, Illinois, is just outside the southeast corner of

the area. Interstates 55, 57, 65, 80, 90, 94, and 294 as well as

numerous State and Federal highways cross the area. The Great

Lakes Naval Training Center, O’Hare International Airport,

Midway Airport, and General Mitchell International Airport are

in the area. The Argonne National Laboratory and numerous

forest preserves are in the part of the area in Illinois.

Physiography

The northern half of this area is in the Eastern Lake Section

of the Central Lowland Province of the Interior Plains. The

southern half is in the Till Plains Section of the same province

and division. The area is a nearly level to gently sloping

glaciated plain. It has relatively low relief on the glacial lake

plains and more rolling topography along the major stream

valleys and on glacial moraines. The numerous glacial

moraines in the area tend to form elongated ridges tending from

northwest to southeast. Elevation is about 650 feet (200

meters), increasing gradually from Lake Michigan south.

Streams have cut shallow valleys on much of the plain. Local

relief is typically 10 to 25 feet (3 to 8 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:
of the United States 345

Upper Illinois (0712), 69 percent; Lower Illinois (0713), 13

percent; Southwestern Lake Michigan (0404), 10 percent; and

Wabash (0512), 8 percent. Five major tributaries to the Illinois

River are in this area. They are the Des Plaines, Fox, Vermilion,

Iroquois, and Kankakee Rivers.

Geology

The surface of this area is covered by glacial drift. Till,

outwash, lacustrine deposits, loess or other silty material, and

organic deposits are common. Fractured dolomite and

limestone bedrock of Silurian age lies beneath the glacial drift.

Climate

The average annual precipitation in this area is 31 to 40

inches (785 to 1,015 millimeters). About two-thirds of the

precipitation falls during the freeze-free period. Most of the

rainfall occurs during high-intensity, convective thunderstorms

in summer. Precipitation in winter occurs as snow. The average

annual temperature is 45 to 52 degrees F (7 to 11 degrees C).

The freeze-free period averages about 185 days and ranges from

165 to 205 days. It is longest in a narrow belt along Lake

Michigan.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 3.4%; ground water, 2.1%

Livestock—surface water, 0.0%; ground water, 0.2%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 92.5%; ground water, 1.7%

The total withdrawals average 11,815 million gallons per day

(44,720 million liters per day). This is the fourth highest

amount of water used among all of the MLRAs. About 4 percent

is from ground water sources, and 96 percent is from surface

water sources. In most years the favorably distributed, moderate

precipitation is adequate for crops. Ground water is the primary

source of the municipal water supply, except in the Chicago,

Gary, and Milwaukee areas, where water is taken directly from

Lake Michigan. A few large perennial streams are potential

sources of water but are not extensively used for this purpose.

The surface water generally is suitable for almost all uses. The

water in the Des Plaines River, however, is contaminated by

municipal and industrial wastewater discharges from the

heavily urbanized area around Chicago.

Abundant ground water in shallow glacial outwash deposits

(unconsolidated sand and gravel) meets the domestic and

municipal needs in much of the area. Some irrigation water is

pumped from areas underlain by extensive outwash deposits.

Isolated lenses of sand and gravel buried in the glacial till also

provide some ground water throughout the area. Average values

of total dissolved solids are between 350 and 450 parts per

million (milligrams per liter). The water in these aquifers is very

hard, and the iron concentrations commonly exceed the

national standard for drinking water of 1,000 parts per billion

(micrograms per liter). Some of the deeper wells in the fractured

limestone and dolomite bedrock beneath the glacial drift have

water that is very similar in quality to the water in the glacial

deposits.

Soils

The dominant soil orders in this MLRA are Alfisols,

Histosols, Inceptisols, and Mollisols. The soils in the area have

a mesic soil temperature regime, a udic or aquic soil moisture

regime, and dominantly mixed or illitic mineralogy. They

generally are moderately deep to very deep, poorly drained to

moderately well drained, and silty or clayey in the subsoil.

Nearly level Endoaquolls (Ashkum, Bryce, and Drummer

series) are on broad flats and in shallow depressions.

Moderately well drained Argiudolls (Graymont and Varna

series) formed in loess and loamy till on gently sloping to

sloping uplands. In areas of the more clayey till, somewhat

poorly drained Argiudolls (Clarence, Elliott, and Swygert

series) are more prevalent. Hapludalfs (Kidami and Ozaukee

series) commonly occur on gently sloping to moderately

sloping uplands along the major stream valleys. They also

occur on many of the more sloping glacial moraines.

Moderately well drained Eutrudepts (Chatsworth series)

generally are in the steeper areas. Haplosaprists (Houghton and

Lena series) are common in wet, closed depressions. Loamy,

moderately well drained and well drained Argiudolls (Proctor

and Warsaw series) and Hapludalfs (Camden and Fox series)

are on outwash plains or broad stream terraces underlain by

sand and gravel. Somewhat poorly drained Argiudolls

(Martinton series) and poorly drained Endoaquolls (Milford

series) commonly are on broad glacial lake plains. Cumulic

Endoaquolls (Sawmill series) and Cumulic Hapludolls (Lawson

and Huntsville series) formed in alluvium on nearly level, broad

flood plains and in the smaller upland drainageways.

Biological Resources

When this area was settled, about 60 percent of the total

acreage supported prairie vegetation. The present potential for

natural vegetation on the prairies in the area is unknown.

Cattails, bulrushes, and common reed grow on organic soils in

marshes. A few bogs support tamarack, pitcherplant, sundew,

cranberry, leatherleaf, winterberry, and dwarf birch. Some of the

major wildlife species in this area are white-tailed deer, coyote,

beaver, raccoon, and Canada goose.
346 Major Land Resource Areas

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 65%

Grassland—private, 4%

Forest—private, 5%

Urban development—private, 22%

Water—private, 2%

Other—private, 2%

Most of this area is in farms, but more than 20 percent is

used for urban development. Some land formerly used for crops

is rapidly becoming urbanized. Farmed areas are used mainly

for cash-grain crops. Corn and other feed grain crops dominate

the area. Hay and pasture crops are grown in support of the

local livestock industry. The forestland in the area is mainly on

wet flood plains, on steeply sloping valley sides, and on ridges

formed by moraines.

The major resource concerns on cropland and construction

sites are water erosion, excessive soil wetness, flooding,

sedimentation, surface water quality, storm-water management,

and protection and restoration of wetland habitat. Conservation

practices on cropland generally include systems of crop residue

management (such as mulch-till, no-till, and strip-till systems),

cover crops, conservation cropping systems, crop rotations, and

maintenance of tile drainage systems, which improve soil

aeration and increase the rooting depth. Grassed waterways,

grade-stabilization structures, and filter strips help to control

concentrated runoff and protect water quality. Nutrient

management and pest management also are important

conservation practices in the area. Urban storm-water

management helps to control flooding and improves water

quality in this heavily urbanized area. 

111A—Indiana and Ohio Till Plain,

Central Part

This area (shown in fig. 111A-1) is in the central part of

Indiana (54 percent) and the southwestern part of Ohio (46

percent). It makes up about 10,980 square miles (28,445 square

kilometers). It includes the towns or cities of Anderson,

Columbus, Indianapolis, Kokomo, Muncie, Plainfield, and

Richmond, Indiana, and Dayton, Eaton, Greenville, Springfield,

and Washington Court House, Ohio. Columbus, the capital of

Ohio, is just outside the eastern edge of the area. Interstates 65,

69, 70, 71, 74, and 75 cross the area. Numerous State parks

occur in this area. The Fort Harrison, Mounds, Summit Lake,

and White River State Parks are in the part of the area in

Indiana, and Buck Creek, Deer Creek, John Bryan, Kiser Lake,

Little Miami, Madison Lake, and Sycamore State Parks are in

the part in Ohio.

Physiography

This area is in the Till Plains Section of the Central

Lowland Province of the Interior Plains. It is dominated by

broad, nearly level ground moraines that are broken in some

areas by kames, outwash plains, and stream valleys along the

leading edge of the moraines. Narrow, shallow valleys

commonly are along the few large streams in the area. Elevation

ranges from 680 to 1,250 feet (205 to 380 meters), increasing

gradually from west to east. Relief is mainly a few meters, but in

some areas hills rise as much as 100 feet (30 meters) above the

adjoining plains.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Wabash (0512), 46 percent; Great Miami (0508), 30 percent;

Scioto (0506), 22 percent; and the Middle Ohio (0509), 2

percent. The major rivers in the area include the East and West

Forks of the White River and the Whitewater River in Indiana

and the Great Miami, Stillwater, Big Darby, Scioto, and Big

Walnut Rivers in Ohio.

Geology

Surface deposits in this area include glacial deposits of till,

lacustrine sediments, and outwash from Wisconsin and older

glacial periods. A moderately thick mantle of loess covers much

of the area. Most of this MLRA is underlain by Silurian and

Figure 111A-1: Location of MLRA 111A in Land Resource Region M.
of the United States 347

Devonian limestone and dolostone. Also, some areas of Late

Ordovician shale and limestone are in the western part of the

MLRA.

Climate

The average annual precipitation in this area is 36 to 43

inches (915 to 1,090 millimeters). Most of the rainfall occurs as

convective thunderstorms during the growing season. About

half or more of the precipitation occurs during the freeze-free

period. Snowfall is common in winter. The average annual

temperature is 49 to 53 degrees F (9 to 12 degrees C). The

freeze-free period averages about 195 days and ranges from 175

to 215 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 6.6%; ground water, 11.0%

Livestock—surface water, 0.3%; ground water, 0.4%

Irrigation—surface water, 0.2%; ground water, 0.1%

Other—surface water, 62.0%; ground water, 19.4%

The total withdrawals average 1,985 million gallons per day

(7,515 million liters per day). About 31 percent is from ground

water sources, and 69 percent is from surface water sources. In

most years the moderate precipitation provides enough water

for crops, but in some years yields are reduced by drought.

Many of the soils require artificial drainage before they can be

used for crops. Reservoirs on the East Fork of the White River

and on the Great Miami and Scioto Rivers and their tributaries

provide water for public, municipal, and industrial supplies and

for cooling thermoelectric power plants. Recreation is the most

significant use of some of the reservoirs. Since an advanced

wastewater treatment facility has been in use in Indianapolis,

the water in the East Fork is now suitable for almost all uses.

Rivers receiving wastewater effluent from the larger urban

centers in Ohio have poor-quality water during periods of low

flow. The water in the other streams and rivers in this area is of

good or fair quality and is suitable for most uses.

Abundant ground water in shallow glaciofluvial deposits

(unconsolidated sand and gravel along streams and in glacial

channels) meets some of the domestic, livestock, municipal, and

industrial needs in the part of this area in Indiana. Also, some

irrigation water is pumped from this aquifer. The extensive sand

and gravel deposits in the valleys along the Great Miami and

Scioto Rivers are heavily used in Ohio. Average values of total

dissolved solids are 416 and 546 parts per million (milligrams

per liter) in Ohio and Indiana, respectively, and the water is

very hard. The water is very low in iron in Indiana, but it

exceeds the secondary (esthetic) standard for drinking water in

Ohio. Isolated lenses of sand and gravel buried in the glacial

till provide some very hard ground water throughout the area.

Average values of total dissolved solids are 358 parts per

million (milligrams per liter), but this water has the highest

levels of iron of all the aquifers in the area. The water is used

primarily for domestic purposes and for watering livestock.

Where the higher yield wells occur, this aquifer provides some

water for irrigation or for municipal and industrial needs. Some

deeper wells in the fractured limestone and dolomite bedrock

beneath the glacial drift have water that is very similar in

quality to the water in the glacial deposits.

Soils

The dominant soil orders in this MLRA are Alfisols,

Inceptisols, and Mollisols. The MLRA also has small areas of

Histosols. The soils in the area have a mesic soil temperature

regime, an aquic or udic soil moisture regime, and mixed

mineralogy. They are very deep, generally are very poorly

drained to somewhat poorly drained, and are loamy or clayey.

The dominant kinds of parent material are till, outwash, and

loess. Others include alluvium, glaciolacustrine sediments,

residuum, and organic deposits. Hapludalfs (Cardington,

Celina, Lewisburg, Losantville, Miami, Miamian, Milton,

Russell, Strawn, Wawaka, Williamstown, and Xenia series) and

Epiaqualfs (Crosby and Fincastle series) are on moraines. Some

Argiaquolls (Brookston, Cyclone, Kokomo, and Treaty series)

are in depressions on ground moraines. Other Argiaquolls

(Lippincott and Westland series) and Endoaquolls (Patton and

Pella series) are in depressions on outwash plains and terraces.

Hapludalfs (Eldean, Fox, Martinsville, and Ockley series) and

Endoaqualfs (Sleeth and Whitaker series) are on terraces and

outwash plains. Haplosaprists (Linwood and Palms series) and

Humaquepts (Martisco series) are in deep depressions or

potholes. Eutrudepts (Eel and Genesee series), Hapludolls (Ross

series), Endoaquepts (Shoals series), and Endoaquolls (Sloan

series) are on flood plains.

Biological Resources

This area supports hardwoods. Pin oak, swamp white oak,

blackgum, American sycamore, green ash, silver maple, and

cottonwood grow on the wetter soils. White oak, northern red

oak, black walnut, tuliptree, shagbark hickory, sugar maple, and

white ash are major species on the better drained soils.

Some of the major wildlife species in this area are whitetailed deer, red fox, gray squirrel, raccoon, opossum, cottontail

rabbit, quail, ducks, turkey, dove, and geese. Fishing is limited

mostly to constructed impoundments, rivers, and streams. The

species of fish in the area include largemouth bass, smallmouth

bass, flathead catfish, bullhead catfish, bluegill, and crappie.
348 Major Land Resource Areas

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 65%

Grassland—private, 6%

Forest—private, 8%

Urban development—private, 17%

Water—private, 1%

Other—private, 3%

Most of this area is farmed. Corn, soybeans, other feed

grains, and hay for livestock are the principal crops. Dairying is

an important enterprise near the cities in the area, and truck and

canning crops are grown extensively in areas where the soils

and markets are favorable. Some small areas along Big Walnut

Creek, Little Walnut Creek, Eagle Creek, and the White River

are irrigated. This MLRA has small acreages of permanent

pasture and farm woodlots. The pressure of urban expansion is

high around the major towns and cities in this populous area.

The major resource concerns are seasonal wetness; water

erosion; maintenance of the content of organic matter and

productivity of the soils; excessive sediments, nutrients, and

pesticides in surface water; nutrients and pesticides in ground

water; and loss of wildlife habitat. Conservation practices on

cropland generally include surface and subsurface drainage

systems, conservation crop rotations, crop residue management,

filter strips, nutrient and pest management, protection of

streambanks, agrichemical containment facilities, and

management of wildlife habitat. 

Figure 111B-1: Location of MLRA 111B in Land Resource Region M.

111B—Indiana and Ohio Till Plain,

Northeastern Part

This area (shown in fig. 111B-1) is in the northwestern part

of Ohio (42 percent), the northeastern part of Indiana (35

percent), and the south-central part of Michigan (23 percent). It

makes up about 13,460 square miles (34,880 square

kilometers). It includes the towns of Fort Wayne, Huntington,

and Marion, Indiana; Pontiac, Adrian, and Ann Arbor,

Michigan; and Bellefontaine, Celina, Delaware, Lima, Marion,

Sidney, and Upper Sandusky, Ohio. Interstates 69, 75, 80, and

90 cross this area. A number of State parks are in the part of the

area in Michigan; the Delaware Lake, Grand Lake St. Marys,

Indian Lake, and Lake Loramie State Parks are in the part in

Ohio; and the Chain O’Lakes and Ouabache State Parks are in

the part in Indiana.

Physiography

This area is in the Eastern Lake and Till Plains Sections of

the Central Lowland Province of the Interior Plains. The entire

MLRA is glaciated, and most areas are dominated by ground

moraines that are broken in places by lake plains, outwash

plains, flood plains, and many recessional moraines. The

ground moraines and lake plains in front of the recessional

moraines are flat to undulating. In many places stream valleys

occur at the leading edge of the recessional moraines. Narrow,

shallow valleys commonly are along the large streams in this

MLRA, and some areas along the major rivers and streams have

deposits of sand. Elevation ranges from 630 to 1,550 feet (190

to 470 meters), increasing gradually from west to east. Relief is

mainly a few meters, but in some areas hills rise as much as 100

feet (30 meters) above the adjoining plains.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Western Lake Erie (0410), 41 percent; Wabash (0512), 28

percent; Scioto (0506), 10 percent; St. Clair-Detroit (0409), 9

percent; Great Miami (0508), 6 percent; Southeastern Lake

Michigan (0405), 5 percent; and Southwestern Lake HuronLake Huron (0408), 1 percent. The Huron River in Michigan,

Cedar Creek in Indiana, and the Sandusky River in Ohio have

been designated as National Wild and Scenic Rivers in this

MLRA.

Geology

The surficial materials in this area include glacial deposits of

till, outwash, and lacustrine sediments from Wisconsin and

older glacial periods. A thin mantle of loess occurs in some
of the United States 349

areas. Most of this MLRA is underlain by Silurian and

Devonian limestone and dolostone. Middle Devonian to Early

Mississippian black shale and Early to Middle Mississippian

siltstone and shale are in some areas of the northern part of the

MLRA.

Climate

The average annual precipitation in this area is 30 to 39

inches (760 to 990 millimeters). Most of the rainfall occurs as

convective thunderstorms during the growing season. About

half or more of the annual precipitation occurs during the

freeze-free period. Snowfall is common in winter. The average

annual temperature is 47 to 52 degrees F (8 to 11 degrees C).

The freeze-free period averages about 180 days and ranges from

165 to 195 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 10.2%; ground water, 7.7%

Livestock—surface water, 0.3%; ground water, 0.4%

Irrigation—surface water, 0.4%; ground water, 0.4%

Other—surface water, 70.0%; ground water, 10.5%

The total withdrawals average 1,715 million gallons per day

(6,490 million liters per day). About 19 percent is from ground

water sources, and 81 percent is from surface water sources. In

most years the moderate precipitation provides enough water

for crops, but in some years yields are reduced by drought.

Many of the soils require artificial drainage before they can be

used for crops. Reservoirs in the part of the area in Indiana, the

rivers in the part in Ohio, and the rivers and lakes in the part in

Michigan provide water for public, municipal, and industrial

supplies and for cooling thermoelectric power plants.

Recreation is the most important use of some of the reservoirs.

The surface water is suitable for almost all uses.

Abundant ground water in shallow glaciofluvial deposits

(unconsolidated sand and gravel along streams and in glacial

channels) meets some of the domestic, livestock, municipal,

and industrial needs in this area. Also, some irrigation water

is pumped from this aquifer. Deposits along the Great Miami

and Scioto Rivers are pumped heavily. Average values of total

dissolved solids are 185, 413, and 546 parts per million

(milligrams per liter) in Michigan, Ohio, and Indiana,

respectively. The water generally is very hard, but in Michigan

it typically is moderately hard or hard. It is very low in iron in

Indiana, but it typically exceeds the secondary (esthetic)

national standard for drinking water in Michigan and Ohio.

A glacial outwash aquifer consisting of a deposit of sand and

gravel in northern Indiana and in Michigan is more extensive

than the glaciofluvial deposits. The water from this aquifer has

less than 500 parts per million (milligrams per liter) total

dissolved solids, and it is very hard. Iron levels are very high.

Isolated lenses of sand and gravel buried in the glacial till

provide some very hard ground water throughout the area.

Average values of total dissolved solids are 358 parts per

million (milligrams per liter), but this water has the highest

levels of iron of all the aquifers in the area. The two glacial

aquifers provide water primarily for domestic use and livestock.

Where the higher yield wells occur, the outwash aquifer

provides some water for irrigation or for municipal and

industrial needs. Some deeper wells in the fractured limestone

and dolomite bedrock beneath the glacial drift have water that

is very similar in quality to the water in the glacial deposits.

This bedrock provides most of the industrial, agricultural, and

domestic water in west-central Ohio.

Soils

The dominant soil orders in this MLRA are Alfisols,

Inceptisols, and Mollisols. The soils in the area have a mesic

soil temperature regime, an aquic or udic soil moisture regime,

and mixed or illitic mineralogy. They are very deep, generally

are very poorly drained to somewhat poorly drained, and are

loamy or clayey. The dominant kinds of parent material are

clayey till and lacustrine sediments. Others include outwash,

alluvium, loess, and organic deposits. Hapludalfs (Glynwood

and Morley series), Epiaqualfs (Blount, Nappanee, and Pandora

series), Endoaqualfs (Wetzel series), and Argiaquolls (Pewamo

series) are on till plains. Endoaquolls (Milford and

Montgomery series) and Epiaqualfs (Del Rey series) are on lake

plains. Haplosaprists (Houghton and Linwood series),

Humaquepts (Roundhead and Wallkill series), and

Endoaquepts (Wunabuna series) are in deep depressions or

potholes. Hapludalfs (Belmore, Eldean, and Fox series),

Endoaqualfs (Sleeth series), and Argiaquolls (Millgrove,

Rensselaer, and Westland series) are on terraces and outwash

plains. Eutrudepts (Genesee series), Endoaquepts (Shoals

series), and Endoaquolls (Saranac and Sloan series) are on flood

plains.

Biological Resources

This area supports hardwoods. Pin oak, swamp white oak,

blackgum, American sycamore, green ash, silver maple, and

cottonwood grow on the wetter soils. White oak, northern red

oak, black walnut, tuliptree, shagbark hickory, sugar maple, and

white ash are major species on the better drained soils.

Some of the major wildlife species in this area are whitetailed deer, red fox, gray squirrel, raccoon, opossum, cottontail

rabbit, quail, ducks, turkey, dove, and geese. Fishing is limited

mostly to constructed impoundments and to rivers and streams.

The species of fish in the area include largemouth bass,

smallmouth bass, flathead catfish, bullhead catfish, bluegill, and

crappie.
350 Major Land Resource Areas

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 76%

Grassland—private, 3%

Forest—private, 7%; Federal, 1%

Urban development—private, 8%

Water—private, 1%

Other—private, 4%

More than 80 percent of this area is farmed. Corn, soybeans,

other feed grains, and hay for livestock are the principal crops.

Dairying is an important enterprise near cities, and truck and

canning crops are grown extensively in areas where the soils

and markets are favorable. Some small areas along the major

rivers are irrigated. This MLRA has small acreages of

permanent pasture and farm woodlots.

The major resource concerns are seasonal wetness; water

erosion; maintenance of the content of organic matter and

productivity of the soils; excessive sediments, nutrients, and

pesticides in surface water; nutrients and pesticides in ground

water; and loss of wildlife habitat. Conservation practices on

cropland generally include surface and subsurface drainage

systems, conservation crop rotations, crop residue management,

filter strips, nutrient and pest management, protection of

streambanks, agrichemical containment facilities, and

management of wildlife habitat. 

Figure 111C-1: Location of MLRA 111C in Land Resource Region M.

111C—Indiana and Ohio Till Plain,

Northwestern Part

This area is almost entirely in Indiana (fig. 111C-1). A very

small part is in Michigan. The area makes up about 3,500

square miles (9,065 square kilometers). The towns of

Logansport, Plymouth, Syracuse, and Rensselaer, Indiana, are

in this MLRA. Interstate 65 crosses the southwestern part of the

area, and Interstate 69 crosses the northeast tip.

Physiography

Almost all of this area is in the Eastern Lake Section of the

Central Lowland Province of the Interior Plains. The southern

end of the area is in the Till Plains Section of the same province

and division. This MLRA is in the glaciated part of northcentral Indiana. It has a series of end moraines throughout.

Areas that parallel most of the major rivers and streams have

deposits of sand. Most of the MLRA is dominated by glacial

till plains broken in places by lake plains, outwash plains, and

flood plains. Narrow, shallow valleys commonly are along the

large streams in the MLRA. In many places stream valleys

occur at the edge of moraines that represent different episodes

of glacial advancement and retreat. Elevation ranges from 630

to 940 feet (190 to 285 meters), increasing gradually from west

to east. Relief is mainly a few meters, but in some areas hills rise

as much as 100 feet (30 meters) above the adjoining plains.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Wabash (0512), 53 percent; Upper Illinois (0712), 24 percent;

Southeastern Lake Michigan (0405), 22 percent; and Western

Lake Erie (0410), 1 percent. The Eel, Wabash, Pigeon,

Tippecanoe, and St. Joseph Rivers cross this area.

Geology

The surficial materials in this area include glacial deposits of

till, outwash, and lacustrine sediments from Wisconsin and

older glacial periods. A thin or moderately thick mantle of loess

covers much of the area. This MLRA is underlain by Late

Ordovician shale and limestone. The western part is underlain

by shale, siltstone, sandstone, limestone, and dolostone ranging

in age from Middle Pennsylvanian to Silurian.

Climate

The average annual precipitation in this area is 35 to 39

inches (890 to 990 millimeters). About half or more of the
of the United States 351

annual precipitation occurs during the freeze-free period. Most

of the rainfall occurs as convective thunderstorms during the

summer. The low amount of precipitation in winter occurs

mostly as snow. The average annual temperature is 47 to 51

degrees F (9 to 11 degrees C). The freeze-free period averages

about 185 days and ranges from 170 to 195 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 15.9%; ground water, 13.0%

Livestock—surface water, 16.9%; ground water, 14.0%

Irrigation—surface water, 20.8%; ground water, 19.3%

Other—surface water, 0.0%; ground water, 0.0%

The total withdrawals average 21 million gallons per day (80

million liters per day). About 46 percent is from ground water

sources, and 54 percent is from surface water sources. In normal

years the favorably distributed, moderate precipitation is

adequate for crops, but in some years yields are reduced by

drought. A few large streams, mainly tributaries of the Wabash

and St. Joseph Rivers, are potential sources of surface water.

Some surface water is used for public, municipal, and industrial

supplies and for irrigation. A few lakes in the northern part of

the area are widely used for recreation. The surface water is

suitable for almost all uses.

A glacial outwash aquifer consisting of a deposit of sand and

gravel in northern Indiana and in Michigan has water with

about 440 parts per million (milligrams per liter) total dissolved

solids. The water is very hard. Iron levels are very high. Isolated

lenses of sand and gravel buried in the glacial till provide some

very hard ground water throughout the area. Average values of

total dissolved solids are 358 parts per million (milligrams per

liter), but this water has the highest levels of iron of all the

aquifers in the area. The two glacial aquifers provide water

primarily for domestic use and livestock. Where the higher

yield wells occur, the outwash aquifer provides some water for

irrigation and for public, municipal, and industrial needs. Some

deeper wells in the fractured Silurian-Devonian limestone

beneath the glacial drift have water that is very similar in

quality to the water in the glacial deposits.

Soils

The soils in this area are mostly Alfisols, Mollisols, Entisols,

Inceptisols, or Histosols. They generally are deep and medium

textured to fine textured and have a mesic soil temperature

regime, an aquic or udic soil moisture regime, and mixed or

illitic mineralogy. They formed in calcareous, loamy glacial

till. Gently sloping or moderately sloping, moderately well

drained or well drained Hapludalfs (Miami, Riddles,

Williamstown, and Oshtemo series) are on summits. Level or

nearly level, somewhat poorly drained, clayey Epiaqualfs

(Conover, Baugo, and Crosier series) are on flat uplands; in

broad, flat depressions; and in drainageways. Poorly drained or

very poorly drained Argiaquolls (Brookston, Treaty, and

Rennselaer series), Endoaquolls (Milford, Patton, and Pella

series), and Haplosaprists (Adrian, Edwards, Houghton,

Muskego, and Madaus series) are on narrow flats and in deep

depressions or potholes.

Biological Resources

This area supports hardwoods. Pin oak, swamp white oak,

blackgum, American sycamore, green ash, silver maple, and

cottonwood grow on the wetter soils. White oak, northern red

oak, black walnut, tuliptree, shagbark hickory, sugar maple, and

white ash are major species on the better drained soils.

Some of the major wildlife species in this area are whitetailed deer, red fox, gray squirrel, raccoon, opossum, cottontail

rabbit, quail, ducks, turkey, dove, and geese. Fishing is limited

mostly to constructed impoundments and to rivers and streams.

The species of fish in the area include largemouth bass,

smallmouth bass, flathead catfish, bullhead catfish, bluegill, and

crappie.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 58%

Grassland—private, 5%

Forest—private, 13%

Urban development—private, 14%

Water—private, 3%

Other—private, 7%

Most of this area is farmed. Corn, soybeans, other feed

grains, and hay for livestock are the principal crops. Dairying is

an important enterprise near cities, and truck and canning crops

are grown extensively in areas where the soils and markets are

favorable. Some small areas along the Eel, Wabash, Pigeon,

Tippecanoe, and St. Joseph Rivers are irrigated. This MLRA

has small acreages of permanent pasture and small farm

woodlots.

The major resource concerns are water erosion,

maintenance of the fertility and productivity of the soils, and

soil moisture management. Conservation practices on cropland

generally include systems of crop residue management

(especially no-till systems that eliminate the need for fall and

spring fallow tillage), cover crops, nutrient management,

terraces, water- and sediment-control basins, grassed waterways,

and diversions. 
352 Major Land Resource Areas

Figure 111D-1: Location of MLRA 111D in Land Resource Region M.

111D—Indiana and Ohio Till Plain,

Western Part

This MLRA occurs in two separate areas (fig. 111D-1). One

area is in the west-central part of Indiana (73 percent), and the

other is in southwestern Ohio (27 percent). The MLRA makes

up 5,355 square miles (13,880 square kilometers). It includes

the towns of Crawfordville, Delphi, Frankfort, Lafayette, and

Liberty, Indiana, and Hamilton, Lebanon, Middletown, and

Wilmington, Ohio. Interstates 65 and 74 cross the part of this

area in Indiana, and Interstates 71 and 75 cross the part in Ohio.

Shades and Turkey Run State Parks are in the part in Indiana,

and Caesar Creek and Hueston Woods State Parks are in the

part in Ohio. A small portion of the Wright-Patterson Air Force

Base, in Ohio, is in the northern part of the area.

Physiography

This area is in the Till Plains Section of the Central Lowland

Province of the Interior Plains. It is dominated by loess hills

and flats that are broken in places by moraines, kames, outwash

plains, and stream terraces. Narrow, shallow valleys commonly

are along the few large streams in the area. Elevation ranges

from 530 to 1,050 feet (160 to 320 meters), increasing

gradually from southwest to northeast. Relief is mainly a few

meters, but in some areas hills rise as much as 100 feet (30

meters) above the adjoining plains.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Wabash (0512), 68 percent; Great Miami (0508), 15 percent;

Middle Ohio (0509), 14 percent; Scioto (0506,) 2 percent; and

Upper Illinois (0712), 1 percent. Wildcat Creek in Indiana and

the Little Miami River in Ohio have been designated as

National Wild and Scenic Rivers. Sugar Creek and Walnut

Creek occur in the part of the area in northern Indiana, and the

Whitewater River is in the part in southeastern Indiana. The

Sevenmile, Fourmile, and Great Miami Rivers cross the part of

the area in Ohio.

Geology

Most of the eastern part of this MLRA is underlain by Late

Ordovician shale and limestone. The western part is underlain

by shale, siltstone, sandstone, limestone, and dolostone ranging

in age from Middle Pennsylvanian to Silurian. Surficial

materials include glacial deposits of till, outwash, and lacustrine

sediments from Wisconsin and older glacial periods. A thin or

moderately thick mantle of loess overlies much of the area.

Climate

The average annual precipitation in this area is 36 to 43

inches (915 to 1,090 millimeters). Most of the rainfall occurs as

convective thunderstorms during the growing season. About

half or more of the precipitation occurs during the freeze-free

period. Snowfall is common in winter. The average annual

temperature is 49 to 54 degrees F (10 to 12 degrees C). The

freeze-free period averages about 200 days and ranges from 180

to 215 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 10.6%; ground water, 35.3%

Livestock—surface water, 1.4%; ground water, 1.5%

Irrigation—surface water, 1.3%; ground water, 0.2%

Other—surface water, 26.9%; ground water, 22.8%

The total withdrawals average 240 million gallons per day

(910 million liters per day). About 60 percent is from ground

water sources, and 40 percent is from surface water sources. In

most years the moderate precipitation provides enough water

for crops, but in some years yields are reduced by drought. A

few large streams, mainly tributaries of the Ohio River, are

potential sources of surface water. Some surface water is used

for public, municipal, and industrial supplies and for irrigation.

A few lakes in the area are used mostly for recreation. The

surface water in the area is suitable for almost all uses.

A glacial outwash aquifer in northern Indiana is one source

of ground water in this area. It is a sand and gravel deposit that
of the United States 353

has water with about 440 parts per million (milligrams per liter)

total dissolved solids. The water is very hard. Iron levels are

very high. Isolated lenses of sand and gravel buried in the

glacial till provide some very hard ground water throughout the

area. Average values of total dissolved solids are 358 parts per

million (milligrams per liter), but this water has the highest

levels of iron of all the aquifers in the area. The two glacial

aquifers provide water primarily for domestic use and for

livestock. Where the higher yield wells occur, the outwash

aquifer provides some water for irrigation and for public,

municipal, and industrial needs. Some deeper wells in the

fractured Silurian-Devonian limestone beneath the glacial drift

have water that is very similar in quality to the water in the

glacial deposits.

Glaciofluvial deposits of sand and gravel in the valleys

along the Whitewater and Great Miami Rivers are primary

sources of ground water in the parts of this area in southeastern

Indiana and southwestern Ohio, respectively. The median level

of total dissolved solids in the ground water beneath these two

river valleys is 546 and 413 parts per million (milligrams per

liter), respectively, and the water in both aquifers is very hard.

There has been no contamination of these shallow aquifers to

date. The Shaly Carbonate bedrock aquifer beneath this area is

not used because abundant good-quality water is available in

the river valley deposits.

Soils

The dominant soil orders in this MLRA are Alfisols,

Inceptisols, and Mollisols. The MLRA also has small areas of

Histosols. The soils in the area have a mesic soil temperature

regime, an aquic or udic soil moisture regime, and mixed

mineralogy. They are dominantly very deep, very poorly

drained to well drained, and loamy or silty. The dominant kinds

of parent material are till, outwash, loess, and alluvium.

Hapludalfs (Celina, Miami, Miamian, Reesville, Russell, Wynn,

and Xenia series) and Epiaqualfs (Crosby and Fincastle series)

are on till plains. Endoaquolls (Drummer series), Argiaquolls

(Cyclone, Kokomo, Mahalasville, Ragsdale, and Treaty series),

and Endoaqualfs (Starks series) are on till plains or outwash

plains. Haplosaprists (Houghton and Palms series) are in deep

depressions and potholes. Hapludalfs (Camden, Eldean, Fox,

Martinsville, and Ockley series) and Endoaqualfs (Sleeth series)

are on terraces and outwash plains. Argiaquolls (Westland

series) are in depressions on terraces and outwash plains.

Eutrudepts (Beckville, Eel, and Genesee series), Endoaquepts

(Shoals series), and Endoaquolls (Sloan series) are on flood

plains.

Biological Resources

When this area was settled, the broad, nearly level uplands

in the northwestern part of the MLRA supported prairie

vegetation. The rest of the MLRA supported hardwoods. Pin

oak, swamp white oak, blackgum, American sycamore, green

ash, silver maple, and cottonwood grow on the wetter soils.

White oak, northern red oak, black walnut, tuliptree, shagbark

hickory, sugar maple, and white ash are the major species on the

better drained soils.

Some of the major wildlife species in this area are whitetailed deer, red fox, gray squirrel, raccoon, opossum, cottontail

rabbit, quail, ducks, turkey, dove, and geese. Fishing is limited

mostly to constructed impoundments and to rivers and streams.

The species of fish in the area include largemouth bass,

smallmouth bass, flathead catfish, bullhead catfish, bluegill, and

crappie.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 74%

Grassland—private, 5%

Forest—private, 11%

Urban development—private, 6%

Water—private, 1%

Other—private, 3%

Almost all of this area is in farms. Corn, soybeans, other feed

grains, and hay for livestock are the principal crops. Dairying is

an important enterprise on some farms near cities, and truck and

canning crops are grown in areas where the soils and markets

are favorable. The MLRA has small acreages of permanent

pasture and farm woodlots. The pressure of urban expansion is

high around the major towns and cities in the area.

The major resource concerns are seasonal wetness; water

erosion; maintenance of the content of organic matter and

productivity of the soils; excessive sediments, nutrients, and

pesticides in surface water; nutrients and pesticides in ground

water; and loss of wildlife habitat. Conservation practices on

cropland generally include surface and subsurface drainage

systems, conservation crop rotations, crop residue management,

filter strips, nutrient and pest management, protection of

streambanks, agrichemical containment facilities, and

management of wildlife habitat. 

111E—Indiana and Ohio Till Plain,

Eastern Part

This area is entirely in the north-central part of Ohio (fig.

111E-1). It makes up 2,980 square miles (7,720 square

kilometers). The towns of Bucyrus, Ashland, Lancaster, Mount

Gilead, Shelby, Sunbury, and Columbus are in this MLRA.

Interstate 71 crosses the central and northeastern parts of the

area, and Interstate 70 crosses the south-central part. Mount

Gilead State Park is in this MLRA.
354 Major Land Resource Areas

Figure 111E-1: Location of MLRA 111E in Land Resource Region M.

Physiography

Most of this area is in the Till Plains Section of the Central

Lowland Province of the Interior Plains. The northeast tip of the

area is in the Southern New York Section of the Appalachian

Plateaus Province of the Appalachian Highlands. The entire

area has been glaciated. It is dominated by ground moraines

that are broken in places by kames, lake plains, outwash plains,

terraces, and stream valleys. Narrow, shallow valleys commonly

are along the few large streams in the area. Elevation ranges

from 580 to 1,400 feet (175 to 425 meters), increasing

gradually from west to east. Relief is mainly a few meters, but in

some areas hills rise as much as 100 feet (30 meters) above the

adjoining plains.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Scioto (0506), 33 percent; Muskingum (0504), 31 percent;

Western Lake Erie (0410), 28 percent; Upper Ohio (0503), 5

percent; and Southern Lake Erie (0411), 3 percent. The

headwaters of many rivers in central Ohio, including the

Vermilion, Black Fork, Sandusky, Little Scioto, and Olentangy

Rivers, are in this MLRA.

Geology

This MLRA is underlain by late Devonian shale and

sandstone. Surficial materials include glacial deposits of till,

glaciolacustrine sediments, and outwash from Wisconsin and

older glacial periods.

Climate

The average annual precipitation in this area is 35 to 41

inches (890 to 1,040 millimeters). Most of the rainfall occurs as

convective thunderstorms during the growing season. About

half or more of the precipitation occurs during the freeze-free

period. Snowfall is common in winter. The average annual

temperature is 48 to 52 degrees F (9 to 11 degrees C). The

freeze-free period averages about 185 days and ranges from 165

to 205 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 21.6%; ground water, 37.7%

Livestock—surface water, 0.9%; ground water, 1.3%

Irrigation—surface water, 2.1%; ground water, 0.6%

Other—surface water, 29.8%; ground water, 6.0%

The total withdrawals average 84 million gallons per day

(320 million liters per day). About 46 percent is from ground

water sources, and 54 percent is from surface water sources. In

most years the moderate precipitation provides enough water

for crops, but in some years yields are reduced by drought.

Reservoirs are one of the principal sources of water for

industrial and municipal uses. A few large streams are potential

sources of water but are little used. A small quantity of surface

water is diverted for irrigation. A few lakes in the area are used

mostly for recreation. The surface water in the area is suitable

for almost all uses.

Ground water in layers of sand and gravel in ancestral

valleys is a major source of water for industrial and municipal

uses and some limited irrigation. The median level of total

dissolved solids in this aquifer is 413 parts per million

(milligrams per liter), and the water is very hard. There has been

no contamination of this shallow aquifer to date. In areas away

from the deposits of sand and gravel, many communities and

rural landowners rely on wells in the Shaly Sandstone and

Sandstone aquifers that lie beneath the glacial drift. These

aquifers have water that is very similar in quality to the water in

the glacial deposits. Well yields from the Shaly Sandstone are

very low, so some landowners use cisterns.

Soils

The dominant soil orders in this MLRA are Alfisols,

Inceptisols, and Mollisols. The MLRA also has small areas of

Histosols. The soils in the area have a mesic soil temperature

regime, an aquic or udic soil moisture regime, and dominantly
of the United States 355

mixed mineralogy. They are dominantly very deep, very poorly

drained to well drained, and loamy or silty. The dominant kinds

of parent material are till, glaciolacustrine sediments, outwash,

loess, and alluvium. Hapludalfs (Amanda, Cardington, and

Centerburg series), Epiaqualfs (Bennington and Condit series),

and Endoaquolls (Marengo series) are on till plains.

Argiaquolls (Luray and Pewamo series) and Epiaqualfs

(Haskins and Tiro series) are on till plains and lake plains.

Hapludalfs (Chili, Gallman, and Ockley series) and

Endoaqualfs (Sleeth series) are on terraces and outwash plains.

Hapludalfs (Glenford and Mentor series) and Endoaqualfs

(Fitchville and Sebring series) are on lake plains and terraces.

Endoaquolls (Patton series) are in depressions on terraces and

outwash plains. Haplosaprists (Carlisle series) are in deep

depressions and potholes. Eutrudepts (Eel series), Endoaquepts

(Shoals series), and Endoaquolls (Sloan series) are on flood

plains.

Biological Resources

This area supports hardwoods. Pin oak, swamp white oak,

blackgum, American sycamore, green ash, silver maple, and

cottonwood grow on the wetter soils. White oak, northern red

oak, black walnut, tuliptree, shagbark hickory, sugar maple, and

white ash are major species on the better drained soils.

Some of the major wildlife species in this area are whitetailed deer, red fox, gray squirrel, raccoon, opossum, cottontail

rabbit, quail, ducks, turkey, dove, and geese. Fishing is limited

mostly to constructed impoundments and to rivers and streams.

The species of fish in the area include largemouth bass,

smallmouth bass, flathead catfish, bullhead catfish, bluegill, and

crappie.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 58%

Grassland—private, 5%

Forest—private, 18%

Urban development—private, 14%

Water—private, 1%

Other—private, 4%

Most of this area is farmed. Corn, soybeans, other feed

grains, and hay for livestock are the principal crops. Dairying is

an important enterprise on some farms near cities. Some truck

and canning crops are grown in areas where the soils and

markets are favorable. The MLRA has small acreages of

permanent pasture and farm woodlots. Urban development and

recreational development are important land uses in the area.

The major resource concerns are seasonal wetness; water

erosion; maintenance of the content of organic matter and

productivity of the soils; excessive sediments, nutrients, and

pesticides in surface water; nutrients and pesticides in ground

water; and loss of wildlife habitat. Conservation practices on

cropland generally include surface and subsurface drainage

systems, conservation crop rotations, crop residue management,

filter strips, nutrient and pest management, protection of

streambanks, agrichemical containment facilities, and

management of wildlife habitat. 

Figure 112-1: Location of MLRA 112 in Land Resource Region M.

112—Cherokee Prairies

This area (shown in fig. 112-1) is in Kansas (49 percent),

Missouri (26 percent), and Oklahoma (25 percent). It makes up

about 23,840 square miles (61,775 square kilometers). The

southern and western suburbs of Kansas City are in the

northeast corner of this MLRA. The city of Emporia, Kansas, is

along Interstate 35 in the northwest corner of the area. The area

includes the towns of Iola, Chanute, Pittsburg, Parsons,

Independence, and Coffeyville, Kansas; Miami, Claremore, and

Broken Arrow, Oklahoma; and Harrisonville, Warrensburg,

Sedalia, and Clinton, Missouri. It also includes the cities of

Bartlesville and Tulsa, Oklahoma. A short stretch of Interstate

70 is in this area, and Interstates 35 and 44 cross the area.

Physiography

This area is in the Osage Plains Section of the Central

Lowland Province of the Interior Plains. It is an area of gently
356 Major Land Resource Areas

sloping to rolling, dissected plains. Elevation ranges from 330

to 1,310 feet (100 to 400 meters). Even though the area is

thoroughly dissected, local relief typically is only 3 to 10 feet (1

to 3 meters), and major valleys generally are less than 8 feet (25

meters) below the adjacent uplands.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Neosho-Verdigris (1107), 47 percent; Gasconade-Osage (1029),

35 percent; Lower Missouri (1030), 8 percent; North Canadian

(1110), 5 percent; Lower Arkansas (1111), 4 percent; and

Kansas (1027), 1 percent. The Neosho, Marais des Cygnes, and

Verdigris Rivers are the larger rivers in the part of this area in

Kansas. Major reservoirs used for water supply and recreation

are on the Verdigris and Grand (Neosho) Rivers in the part of

the area in Oklahoma. The Harry Truman Reservoir, the

westernmost lake in the popular recreational area called Lake of

the Ozarks, is on the Little Osage and Grand Rivers in the part

of the area in western Missouri.

Geology

Almost all of this area is underlain by Permian,

Pennsylvanian, and Mississippian sandstone, shale, and

limestone bedrock. The northern part of the area has a thin

mantle of loess.

Climate

The average annual precipitation in most of this area is 34 to

45 inches (865 to 1,145 millimeters). Most of the rainfall occurs

as high-intensity, convective thunderstorms from late in spring

through autumn. Snow falls in winter, but it does not usually

remain on the ground. The annual snowfall ranges from about 5

inches (12 centimeters) in the southern part of the area to 18

inches (45 centimeters) in the northern part. The average annual

temperature is 53 to 62 degrees F (11 to 17 degrees C). The

freeze-free period averages 220 days and ranges from 185 to

255 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 17.3%; ground water, 1.5%

Livestock—surface water, 2.3%; ground water, 1.0%

Irrigation—surface water, 0.2%; ground water, 4.3%

Other—surface water, 72.5%; ground water, 0.9%

The total withdrawals average 1,270 million gallons per day

(4,805 million liters per day). About 8 percent is from ground

water sources, and 92 percent is from surface water sources. In

many years the moderate precipitation is adequate for crops and

pasture, but in some years summer droughts reduce crop yields.

Small ponds and reservoirs on individual farms are increasingly

important sources of water for livestock. Surface water is

abundant and of good quality in this area. Low flows during

dry periods are a major limitation affecting use of the water.

Large reservoirs have been constructed to augment riverflows.

These reservoirs provide water for industrial use and public

supplies. Water from the John Redmond Reservoir on the upper

Neosho River is piped to a nuclear power plant for use in

evaporative cooling.

In much of the area, shallow wells are the principal sources

of water for domestic use and for livestock. The Douglas aquifer

is utilized in the part of the area in Kansas. Water in this aquifer

is hard but typically has less than 500 parts per million

(milligrams per liter) total dissolved solids. The Keokuk-Reeds

Spring and Roubidoux aquifers in the northeast corner of

Oklahoma also are used. Water from the Roubidoux aquifer is

low in total dissolved solids, having a median level of 280 parts

per million (milligrams per liter), and it is used for public

supply. This water is hard. There is no information available

about the Keokuk-Reeds Spring aquifer. Water for irrigation

and domestic use is pumped from alluvial aquifers in the

southern end of this area, in Oklahoma. Deep wells, especially

in the dolomite and minor sandstone layers in the Ozark aquifer

in western Missouri, provide water for all uses. The Ozark water

has a median concentration of 322 parts per million (milligrams

per liter) total dissolved solids.

Soils

The dominant soil orders in this MLRA are Mollisols and

Alfisols. The MLRA also has small areas of Vertisols. The soils

in the area dominantly have a thermic soil temperature regime,

an aquic or udic soil moisture regime, and mixed or smectitic

mineralogy. They generally are moderately deep to very deep,

well drained to poorly drained, and loamy or clayey.

Hapludolls formed in alluvium on flood plains (Verdigris series)

and in residuum on uplands (Zaar series). Argiudolls formed in

residuum (Bates, Catoosa, Clareson, and Eram series) and

colluvium mixed with residuum (Dennis, Martin, and Summit

series) on uplands. Argiudolls (Kenoma series), Albaqualfs

(Parsons series), and Argiaquolls (Woodson series) formed in

old alluvium on plains. Hapludalfs formed in residuum (Barco

and Barden series). Epiaquerts (Osage series) formed in

alluvium on flood plains and stream terraces.

Biological Resources

The western part of this area generally supports tall prairie

grasses. Big bluestem, little bluestem, Indiangrass, and

switchgrass are the main species. The eastern part of the area

and the valleys in the western part support natural vegetation

characterized by trees, mainly red oak, white oak, and shagbark

hickory. Islands of tall prairie grasses are common.

Some of the major wildlife species in this area are whitetailed deer, cottontail rabbit, fox squirrel, bobwhite quail, and
of the United States 357

mourning dove. The species of fish in the area include bass,

bluegill, crappie, carp, channel catfish, black bullhead, and

flathead catfish.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 35%

Grassland—private, 43%; Federal, 1%

Forest—private, 11%

Urban development—private, 6%

Water—private, 2%

Other—private, 2%

Nearly all of this area is farmed. Winter wheat, soybeans,

corn, grain sorghum, other feed grains, and hay are the major

crops. Some cotton is grown in a few counties in Oklahoma.

More than two-fifths of the area supports pasture grasses and

legumes. Native grasses grow in the more sloping areas.

Forested areas are on the steeper valley slopes and on some of

the wet bottom land. The forested acreage is considerably less

in Kansas than in Missouri and Oklahoma.

The major resource concerns on cropland are water erosion,

maintenance of the content of organic matter in the soils,

surface compaction, and low pH in the soils. The major resource

concerns on pasture and rangeland are plant productivity,

health, and vigor and noxious and invasive plants.

Conservation practices on cropland generally include highresidue crops in the cropping system, systems of crop residue

management (such as no-till, strip-till, and mulch-till systems),

a combination of gradient terraces and grassed waterways,

contour farming, conservation crop rotations, and nutrient and

pest management. Conservation practices on rangeland

generally include prescribed grazing, brush management, and

proper distribution of watering facilities. 

Figure 113-1: Location of MLRA 113 in Land Resource Region M.

113—Central Claypan Areas

This MLRA is in two separate areas (fig. 113-1). One area is

in Illinois (69 percent), and the other is in Missouri (31

percent). The MLRA makes up about 12,790 square miles

(33,150 square kilometers). It includes the towns of Moberly

and Mexico, Missouri, and Effingham, Mount Vernon,

Centralia, Herrin, Marion, and Carbondale, Illinois. Interstates

57 and 64 cross near the center of the area in Illinois. Interstate

70 crosses the extreme northern part of the area in Missouri.

Parts of the Shawnee National Forest, Crab Orchard National

Wildlife Refuge, and a Federal prison near the refuge are in the

southern end of the area in Illinois.

Physiography

The part of this area in Illinois is in the Till Plains Section of

the Central Lowland Province of the Interior Plains. The part in

Missouri is in the Dissected Till Plains Section of the same

province and division. This MLRA consists of nearly level to

gently sloping, old till plains. Stream valleys are shallow and

generally are narrow. Elevation is 660 to 980 feet (200 to 300

meters) in Missouri and about 660 feet (200 meters) in Illinois,

increasing gradually from south to north in both States. Local

relief is generally low on the broad, flat till plains and flood

plains and high on the dissected hills bordering rivers or

drainage systems. It is mainly 5 to 10 feet (1.5 to 3 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Wabash (0512), 36 percent; Upper Mississippi-KaskaskiaMeramec (0714), 28 percent; Upper Mississippi-Salt (0711), 26

percent; Lower Ohio (0514), 6 percent; and Lower Missouri

(1030), 4 percent. The Kaskaskia, Little Muddy, Little Wabash,

Embarras, and Saline Rivers are in the part of this area in

Illinois. Mark Twain Lake, a major reservoir on the Salt River,

and the North and West Forks of the Cuivre River are in the part

of the area in Missouri.
358 Major Land Resource Areas

Geology

This MLRA is covered with loess, which overlies old (preWisconsin) glacial drift that has a high content of clay.

Pennsylvanian limestone and shale bedrock underlies the glacial

till in both Missouri and Illinois.

Climate

The average annual precipitation in most of this area is 36 to

46 inches (915 to 1,170 millimeters). About 60 percent of the

precipitation falls as high-intensity, convective thunderstorms

during the freeze-free period. Snow may fall occasionally in

winter, but it does not remain on the ground for very long

periods. The average annual temperature is 51 to 57 degrees F

(11 to 14 degrees C). The freeze-free period averages about 205

days and ranges from 190 to 225 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 26.5%; ground water, 4.1%

Livestock—surface water, 0.2%; ground water, 0.2%

Irrigation—surface water, 0.0%; ground water, 2.1%

Other—surface water, 62.5%; ground water, 4.3%

The total withdrawals average 450 million gallons per day

(1,705 million liters per day). About 11 percent is from ground

water sources, and 89 percent is from surface water sources. In

most years the moderate precipitation is adequate for crops.

Most of the soils are somewhat poorly drained or poorly

drained, however, and claypans prevent effective artificial

drainage of most of them. Reservoirs have been built on the

larger rivers in this area to provide drinking water and water for

industries. The surface water in the area also is used for cooling

thermoelectric plants and in mineral extraction. It generally is

of good quality.

 Small to moderate quantities of ground water are available

in this area. The supply of ground water from glacial drift in

Missouri is small, undependable, and of poor quality (because

of high concentrations of naturally occurring salts). Wells in the

Pennsylvanian-Mississippian sediments in the part of this area

in Illinois produce low yields. Little is known about the quality

of the water in this aquifer.

Soils

The dominant soil order in this MLRA is Alfisols. The soils

in the area dominantly have a mesic soil temperature regime, an

aquic or udic soil moisture regime, and mixed or smectitic

mineralogy. They generally are very deep, well drained to

poorly drained, and loamy or clayey. Hapludalfs formed in

loess and/or pedisediment over till on uplands (Armstrong,

Hoyleton, and Keswick series) and in till on till plains (Hickory

series). Fragiudalfs (Ava series) formed in loess and/or

pedisediment over till on uplands. Epiaqualfs formed in loess

over pedisediment (Bluford and Mexico series) and loess over

till (Leonard series) on uplands. Albaqualfs formed in loess

(Putnam series), loess over pedisediment (Cisne series), and

loess and/or pedisediment over till (Wynoose series) on

uplands.

Biological Resources

When this MLRA was settled, most of the level soils on

uplands supported tall prairie grasses, mainly big bluestem,

Indiangrass, prairie dropseed, and switchgrass. The present

potential for natural vegetation on these soils is unknown.

Forests of post oak, swamp white oak, blackjack oak, and pin

oak grow on poorly drained soils. White oak, shingle oak,

black oak, hickory, white ash, basswood, sugar maple, elm, and

walnut grow on the better drained soils. Silver maple, willows,

cottonwood, sycamore, elm, pin oak, white oak, hickory, and

ash grow on flood plains.

Some of the major wildlife species in this area are whitetailed deer, coyote, turkey, and bobwhite quail. The species of

fish in the area include carp, catfish, largemouth bass, bluegill,

crappie, and sunfish.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 67%

Grassland—private, 10%; Federal, 1%

Forest—private, 13%

Urban development—private, 5%

Water—private, 2%

Other—private, 2%

Nearly all of this MLRA is farmed. Corn, soybeans, other

feed grains, and hay for cattle and other livestock are the main

crops. The grassland in the area supports introduced and native

grasses. The forested areas are mainly on the steeper slopes and

on wet bottom land.

The major soil resource concerns are wetness, water erosion,

flooding, a limited available water capacity, and maintenance

of the content of organic matter and productivity of the soils,

particularly the soils with a high content of sodium.

Conservation practices on cropland generally include surface

and subsurface drainage systems, crop residue management,

filter strips, cover crops, and nutrient and pest management. 
of the United States 359

Figure 114A-1: Location of MLRA 114A in Land Resource Region M.

114A—Southern Illinois and Indiana

Thin Loess and Till Plain, Eastern Part

This area (shown in fig. 114A-1) is in three separate areas,

one in Indiana (55 percent) and two in Ohio (45 percent). The

MLRA makes up about 4,550 square miles (11,795 square

kilometers). It includes the towns of North Vernon, Seymour,

Versailles, Madison, and New Albany, Indiana, and Fayetteville,

Batavia, and Hillsboro, Ohio. Cincinnati, Ohio, is just west of

this area, and Louisville, Kentucky, is just outside the extreme

southwest corner of the area. Interstate 74 crosses the northern

part of the area, and Interstate 65 crosses the central part from

north to south in Indiana. The Clark and Clifty Falls State

Parks, James F.D. Lanier Historical Site, Jackson-Washington

State Forest, Starve Hollow State Beach, Hardy Lake State

Recreational Area, Muscatatuck and Big Oaks National

Wildlife Refuges, and Versailles State Park are in the part of this

area in Indiana, and Stonelick, East Fork, and Cowan State

Parks and Fort Hill State Memorial are in the part in Ohio. The

Jefferson Proving Ground Military Reservation is in the part in

Indiana.

Physiography

The three parts of this area are mostly in the Till Plains

Section of the Central Lowland Province of the Interior Plains.

The western third of the western part is in the Highland Rim

Section of the Interior Low Plateaus Province of the Interior

Plains. The eastern half of the eastern part is in the Kanawha

Section of the Appalachian Plateaus Province of the

Appalachian Highlands. Both large and small tributaries of the

Ohio River dissect the nearly level to very steep glaciated

uplands in this area. The major streams and rivers have well

defined valleys with broad flood plains and numerous stream

terraces. The flood plains along the smaller streams are narrow.

Broad summits are nearly level to gently sloping. Elevation

ranges from 320 feet (100 meters) on the southernmost flood

plain along the Ohio River to 1,250 feet (380 meters) on the

highest ridges. Local relief is mainly 10 to 50 feet (3 to 15

meters), but it can be 50 to 100 feet (15 to 30 meters) along

drainageways and streams. Also, the Ohio River bluffs are as

much as 300 feet (90 meters) above the river valley floor.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Middle Ohio (0509), 33 percent; Wabash (0512), 33 percent;

Muskingum (0504), 16 percent; Lower Ohio (0514), 9 percent;

Great Miami (0508), 4 percent; Scioto (0506), 3 percent; and

Upper Ohio (0503), 2 percent. The Ohio River flows along the

southernmost boundary of this area, forming the State boundary

between Indiana and Kentucky and between Ohio and

Kentucky. The Ohio River flows southwest and empties into the

Mississippi River to the west of this area, in southern Illinois.

The Muscatatuck, East Fork White, and Laughery Rivers are

the major drainage systems in the part of this MLRA in Indiana.

The White Oak River is the primary drainage in the part in

Ohio. The Little Miami River, a National Wild and Scenic

River, flows along the west edge of this area in Ohio.

Geology

This area is covered with Illinoian-age loess and glacial till

or outwash. The loess ranges from about 3 to 7 feet (1 to 2

meters) in thickness on stable summits and does not occur on

some of the steeper slopes. Acid outwash and alluvial deposits

are on some of the stream terraces along the major tributaries.

The loess and glacial drift deposits are underlain by several

bedrock systems. Middle Devonian to Early and Middle

Mississippian bedrock occurs in the western part of the area;

Ordovician, Silurian, and Devonian bedrock occurs in the

southeastern part; and Middle to Late Mississippian bedrock

occurs in the northeastern part. Bedrock outcrops are common

on the bluffs along rivers and the major tributaries. They also

are evident at the base of steep slopes along minor streams and

drainageways.

Climate

The average annual precipitation in most of this area is 37 to

46 inches (940 to 1,170 millimeters). About 60 percent of the

precipitation falls during the freeze-free period. Most of the

rainfall occurs as high-intensity, convective thunderstorms
360 Major Land Resource Areas

during summer. Snowfall is common in winter. The average

annual temperature is 48 to 57 degrees F (9 to 14 degrees C).

The freeze-free period averages about 190 days and ranges from

155 to 225 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 1.9%; ground water, 2.8%

Livestock—surface water, 0.1%; ground water, 0.2%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 94.0%; ground water, 0.8%

The total withdrawals average 1,180 million gallons per day

(4,465 million liters per day). About 4 percent is from ground

water sources, and 96 percent is from surface water sources. In

most years the supply of moisture is adequate for crop

production, but in some years yields are reduced by drought.

The many springs and streams are sources of surface water in

this area. Some water for livestock is stored in small ponds and

reservoirs. The larger rivers and reservoirs provide water for

industrial and municipal uses and for cooling thermoelectric

power plants. A few large streams are used mostly for recreation.

The surface water in the area is suitable for almost all uses.

Ground water is used mostly for domestic purposes in this

area, but some communities away from surface water sources

use ground water for public, municipal, and industrial supplies.

The primary source of ground water in the part of this area in

Indiana is the fractured limestone in the Silurian-Devonian

aquifer. The median level of total dissolved solids in the water

in this aquifer is 513 parts per million (milligrams per liter), and

the water is very hard. Also, its median level of iron is about

1,100 parts per billion (micrograms per liter), which is over

three times the national secondary (esthetic) standard for

drinking water. Many communities and rural landowners in

Ohio rely on wells in the Shaly Carbonate aquifer, which lies

beneath the glacial drift. This aquifer has water that is very

similar in quality to the water in the bedrock aquifer in Indiana,

but iron is not a problem.

Soils

The dominant soil orders in this MLRA are Alfisols and

Inceptisols. The MLRA also has small areas of Entisols. The

soils in the area have a mesic soil temperature regime, an aquic

or udic soil moisture regime, and mixed mineralogy. They

formed in loess, Illinoian glacial till or outwash, and alluvium

derived from these deposits. The soils are deep or very deep,

poorly drained to well drained, and loamy, silty, or clayey.

Glossaqualfs (Avonburg, Clermont, and Cobbsfork series) are

on broad, flat till plains. Fragiudalfs (Cincinnati, Homewood,

Nabb, and Rossmoyne series) are on gently sloping to strongly

sloping side slopes on till plains. Hapludalfs (Blocher, Bonnell,

and Hickory series) are on moderately sloping to very steep

side slopes on till plains. Hapludalfs (Cana, Grayford, and

Jessup series), Paleudalfs (Ryker series), and Fragiudalfs

(Weisburg series) are on gently sloping to steep side slopes that

are underlain by bedrock residuum. Paleudalfs (Negley series),

Hapludalfs (Parke and Pike series), and Fragiudalfs (Medora

series) formed in outwash deposits on high stream terraces,

kames, and moraines. Fragiudalfs (Otwell and Haubstadt series)

and Fragiaqualfs (Dubois series) formed in a thin layer of loess

and the underlying weathered outwash, lacustrine sediments, or

old alluvium on high stream terraces or lake plains. Eutrudepts

(Haymond, Oldenburg, Wilbur, and Wirt series), Endoaquepts

(Holton and Stendal series), and Fluvaquents (Birds, Bonnie,

and Wakeland series) formed in alluvium on flood plains.

Biological Resources

The soils on uplands support natural hardwoods. Oak,

hickory, beech, and sugar maple are the dominant species.

Some native grasses grow between the oak trees on some sites.

The lowland soils support mixed forest vegetation. Pin oak,

shingle oak, sweetgum, and black oak are the dominant species

on the wetter sites. White oak, black oak, red oak, hickory,

yellow-poplar, ash, sugar maple, and black walnut grow on the

better drained sites. Honeylocust is dominant on soils that

formed in shaly limestone residuum. Silver maple, cottonwood,

sycamore, pin oak, elm, and sweetgum grow along rivers and

streams. Black walnut is abundant on deep, well drained soils

on some small flood plains. Sedge and grass meadows and

scattered trees are on some lowland sites.

Some of the major wildlife species in this area are whitetailed deer, coyote, gray fox, red fox, beaver, raccoon, skunk,

muskrat, opossum, mink, rabbit, fox squirrel, gray squirrel,

Canada goose, turkey vulture, turkey, woodcock, great horned

owl, wood duck, pileated woodpecker, red-bellied woodpecker,

and bobwhite quail.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 61%

Grassland—private, 9%

Forest—private, 17%

Urban development—private, 8%

Water—private, 2%

Other—private, 3%

Most of this area is in privately owned farms. The farms

produce both cash-grain crops and livestock. The less sloping

soils are used for dry-farmed corn for grain and for soybeans.

Some small grains, including winter wheat, oats, and grain

sorghum, also are grown. Specialty crops, such as tobacco and
of the United States 361

apple orchards, make up a small acreage in the area. The

grassland in the area supports introduced and native grasses.

The major soil resource concerns are water erosion, flooding,

wetness, a limited available water capacity, and maintenance of

the content of organic matter and productivity of the soils.

Conservation practices on cropland generally include surface

and subsurface drainage systems, crop residue management,

filter strips, cover crops, and nutrient and pest management.

Woodland management practices, such as exclusion of grazing

and timber stand improvement, are important for timber

production. 

Figure 114B-1: Location of MLRA 114B in Land Resource Region M.

114B—Southern Illinois and Indiana

Thin Loess and Till Plain, Western Part

This area (shown in fig. 114B-1) is in two separate areas in

Illinois (66 percent) and Indiana (34 percent). It makes up about

7,005 square miles (18,150 square kilometers). It includes the

towns of Brazil, Bloomfield, Cloverdale, and Spencer, Indiana,

and Carlyle, Nashville, Hillsboro, Greenville, Vandalia, and

Pinckneyville, Illinois. Interstates 55, 64, and 70 cross the part

of the MLRA in Illinois. They converge in St. Louis, which is

just west of this MLRA. The east edge of the Scott Air Force

Base is on the western edge of the area in Illinois. The

numerous State parks in the MLRA include Eldon Hazlet,

South Shore, and Pyramid State Parks in Illinois and Cagles

Mill and McCormick’s Creek State Parks in Indiana.

Physiography

This area is in the Till Plains Section of the Central Lowland

Province of the Interior Plains. Both large and small tributaries

of the West Fork of the White River, the Eel River, the

Kaskaskia River, and the Little Muddy River dissect the nearly

level to very steep uplands. Well defined valleys with broad

flood plains and numerous stream terraces are along the major

streams and rivers. The flood plains along the smaller streams

are narrow. Broad summits are nearly level to gently sloping.

Elevation ranges from 350 feet (105 meters) on the

southernmost flood plains along the Ohio and Wabash Rivers to

1,190 feet (365 meters) on the highest ridges. Local relief is

mainly 10 to 50 feet (3 to 15 meters), but it can be 50 to 100

feet (15 to 30 meters) along drainageways and streams. It

generally is low on broad, flat till plains and flood plains and

high on the dissected hills bordering rivers or drainage systems.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Upper Mississippi-Kaskaskia-Meramec (0714), 45 percent;

Wabash (0512), 34 percent; Lower Illinois (0713), 18 percent;

and Upper Mississippi-Salt (0711), 3 percent. The Macoupin,

Shoal, and Kaskaskia Rivers drain the part of the area in

Illinois. The West Fork of the White River and the Eel River

flow westward through the central part of the area in Indiana

and empty into the Wabash River south of Vincennes, which is

west of this MLRA.

Geology

This area is covered dominantly with loess and Illinoian till.

The loess ranges from about 4 to 7 feet (1 to 2 meters) in

thickness on stable summits. On the steeper slopes, it is 1 foot

or less (0.1 to 0.3 meter) thick or does not occur. Meltwater

outwash and lacustrine and alluvial deposits are along some of

the streams and on terraces along the major tributaries. The

glacial till and loess deposits are underlain by several bedrock

systems. Middle and Late Mississippian bedrock occurs in the

eastern part of the area, and Early and Middle Pennsylvanian

bedrock occurs in the western part. Bedrock outcrops are

common on the bluffs along the large rivers and their major

tributaries. They also occur at the base of some steep slopes

along minor streams and drainageways.

Climate

The average annual precipitation in most of this area is 37 to

46 inches (940 to 1,170 millimeters). About 60 percent of the

precipitation falls during the freeze-free period. Most of the

rainfall occurs as high-intensity, convective thunderstorms

during summer. Snowfall is common in winter. The average

annual temperature is 52 to 56 degrees F (11 to 14 degrees C).
362 Major Land Resource Areas

The freeze-free period averages about 210 days and ranges from

190 to 225 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 91.9%; ground water, 1.8%

Livestock—surface water, 0.4%; ground water, 1.8%

Irrigation—surface water, 0.6%; ground water, 3.4%

Other—surface water, 0.0%; ground water, 0.0%

The total withdrawals average 79 million gallons per day

(300 million liters per day). About 7 percent is from ground

water sources, and 93 percent is from surface water sources. In

most years the supply of moisture is adequate for maximum

crop production, except on sandy soils. The many springs,

streams, and farm ponds are additional sources of surface water

in this area. Some water for livestock is stored in small ponds

and reservoirs. The larger rivers and reservoirs provide water for

industrial and municipal uses and some limited irrigation. A

few large streams are used mostly for recreation. The surface

water in the area is suitable for almost all uses. Water quality is

a concern in sandy areas of the MLRA.

Abundant ground water occurs only in deposits of

unconsolidated sand and gravel along the East and West Forks

of the White River in Indiana and along the Kaskaskia River in

Illinois. These aquifers provide water for the domestic, livestock,

municipal, and industrial needs in the area. Some irrigation water

is pumped. The average values of total dissolved solids are 546

and 500 parts per million (milligrams per liter) in Indiana and

Illinois, respectively, and the water is very hard. The water is very

low in iron in Indiana, but it exceeds the secondary (esthetic)

standard for drinking water in Illinois.

Away from the river valley deposits, the only source of

ground water in Illinois is the Pennsylvanian-Mississippian

aquifer. Water from this aquifer is very hard and has high

amounts of iron. The level of total dissolved solids is 500 to

3,000 parts per million (milligrams per liter). In Indiana, the

only other source of ground water is in isolated lenses of sand

and gravel buried in older glacial till outside the river valleys.

This water is very hard and high in iron, but it has lower levels

of total dissolved solids than the water in the other aquifers.

The low quantities of ground water from the other aquifers are

used primarily for domestic purposes and for watering

livestock.

Soils

The dominant soil orders in this MLRA are Alfisols and

Inceptisols. The MLRA also has small areas of Mollisols,

Ultisols, and Entisols. The soils in the area have a mesic soil

temperature regime, an aquic or udic soil moisture regime, and

mixed or smectitic mineralogy. Most are medium textured or

fine textured.

Somewhat poorly drained or poorly drained Albaqualfs

(Cowden and Marine series), Endoaqualfs (Iva and Oconee

series), Epiaqualfs (Hoosierville series), Glossaqualfs (Vigo

series), and Argiudolls (Herrick series) are on broad, loesscovered till plains. Moderately well drained, gently sloping to

strongly sloping Fragiudalfs are on side slopes on loesscovered till plains (Ava, Cincinnati, Hosmer, and Shakamak

series) and on side slopes that are underlain by bedrock

residuum (Grantsburg series). Somewhat poorly drained and

moderately well drained, gently sloping to strongly sloping

Hapludalfs (Blair, Bunkum, Fishhook, and Homen series) and

Epiaqualfs (Atlas series) are on side slopes that are underlain by

paleosols or pedisediments. Well drained, strongly sloping to

very steep Hapludalfs (Hickory series) are on side slopes on till

plains. Well drained Paleudalfs (Negley series), Hapludults

(Chetwynd series), and Hapludalfs (Parke and Pike series)

formed in outwash deposits on high stream terraces, kames, and

moraines. Moderately well drained Fragiudalfs (Otwell and

Haubstadt series) and somewhat poorly drained Fragiaqualfs

(Dubois series) formed in a thin layer of loess and in the

underlying weathered outwash, lacustrine sediments, or old

alluvium. They are on high stream terraces and lake plains.

Somewhat poorly drained to well drained, nearly level to

strongly sloping Epiaqualfs (Hurst and McGary series) and

Hapludalfs (Colp, Shircliff, and Markland series) formed in

lacustrine sediments on lacustrine terraces and lake plains. Well

drained to poorly drained Eutrudepts (Haymond and Wilbur

series), Endoaquepts (Belknap, Piopolis, and Stendal series),

and Fluvaquents (Birds, Bonnie, and Wakeland series) formed

in alluvium on flood plains. Udorthents (Bethesda, Fairpoint,

and Morristown series) and Udarents (Lenzburg, Minnehaha,

Schuline, and Swanwick series) formed in regolith from surfacemining operations.

Biological Resources

The soils on uplands in this area support natural hardwoods.

Oak, hickory, beech, and sugar maple are the dominant species.

Native grasses grow in some scattered areas between the trees.

The soils on lowlands support mixed forest vegetation. Pin oak,

shingle oak, hickory, sweetgum, and black oak are the

dominant species on the wetter sites. White oak, black oak, red

oak, hickory, yellow-poplar, ash, sugar maple, and black walnut

grow on the better drained sites. Honeylocust is dominant on

soils that formed in shaly limestone residuum. Silver maple,

cottonwood, sycamore, pin oak, elm, and sweetgum grow along

rivers and streams. Black walnut is abundant on deep, well

drained soils on some small flood plains. Sedge and grass

meadows and scattered trees are on some lowland sites.
of the United States 363

Some of the major wildlife species in this area are whitetailed deer, coyote, gray fox, red fox, beaver, raccoon, skunk,

muskrat, opossum, mink, rabbit, fox squirrel, gray squirrel,

Canada goose, turkey vulture, turkey, woodcock, great horned

owl, wood duck, pileated woodpecker, red-bellied woodpecker,

and bobwhite quail.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 47%

Grassland—private, 11%; Federal, 1%

Forest—private, 27%; Federal, 2%

Urban development—private, 7%; Federal, 1%

Water—private, 2%

Other—private, 2%

Most of this area is in privately owned farms, which produce

both cash-grain crops and livestock. The less sloping soils are

used for dry-farmed corn for grain and for soybeans. Some small

grains, dominantly winter wheat and grain sorghum, also are

grown in the area. A small acreage is used for specialty crops,

such as popcorn and apple orchards. The grassland in the area

supports introduced and native grasses. Nearly 30 percent of

the area is forested. Surface coal mines make up a small acreage

of this MLRA.

The major soil resource concerns are wind erosion, water

erosion, flooding, wetness, a limited available water capacity,

and maintenance of the content of organic matter and

productivity of the soils. Conservation practices on cropland

generally include surface and subsurface drainage systems, crop

residue management, filter strips, cover crops, and nutrient and

pest management. Woodland management practices, such as

exclusion of grazing and timber stand improvement, are

important for timber production. 

Figure 115A-1: Location of MLRA 115A in Land Resource Region M.

115A—Central Mississippi Valley Wooded

Slopes, Eastern Part

This area (shown in fig. 115A-1) is primarily in Indiana (63

percent) and Illinois (37 percent). It makes up about 3,690

square miles (9,565 square kilometers). It includes the towns of

Evansville, Sullivan, Vincennes, and Princeton, Indiana; parts

of Terre Haute, Indiana; and Marshall, Newton, Robinson,

Lawrenceville, Olney, Mt. Carmel, Carmi, and Shawneetown,

Illinois. Interstate 64 crosses the southern part of this area, and

Interstate 70 crosses the northern part. U.S. Highway 41

parallels the Illinois-Indiana State border in the part of this area

in Indiana. The George Rogers Clark National Historic Park,

Harmonie State Park, New Harmony State Memorial, and Hovey

Lake State Game Reserve are in the part of the area in Indiana.

Lincoln Trail State Park is in the part in Illinois. The Shawnee

National Forest is just outside the southern end of the part in

Illinois.

Physiography

Most of this area is in the glaciated Till Plains Section of the

Central Lowland Province of the Interior Plains. The southeast

corner is in the Highland Rim Section (locally known as the

Shawnee Hills Section) of the Interior Low Plateaus Province of

the Interior Plains. The nearly level to very steep uplands in

this MLRA are dissected by both large and small tributaries of

the Wabash and Ohio Rivers. Well defined valleys with broad

flood plains and numerous stream terraces are along the major

streams and rivers. The flood plains along the smaller streams

are narrow. Broad summits are nearly level to gently sloping.

Elevation ranges from 320 feet (100 meters) on the

southernmost flood plains along the Ohio and Wabash Rivers to

1,020 feet (310 meters) on the highest ridges. Relief is

generally 10 to 50 feet (3 to 15 meters) in the undulating or

rolling loess hills. It can be 50 to 150 feet (15 to 45 meters) in

the steep, deeply dissected hills bordering rivers or drainage

systems. The nearly level flood plains have very little relief.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Wabash (0512), 82 percent, and Lower Ohio (0514), 18 percent.

The Wabash River flows southward through this area, forming

the boundaries between Indiana and Illinois. The Ohio River
364 Major Land Resource Areas

flows along the southern border of the area, forming the

boundaries between Indiana and Kentucky and between Illinois

and Kentucky. From north to south, the major rivers in the part

of the area in Illinois are the Mill, Embarras, Bonpas, and Little

Wabash Rivers. The White River flows westward through the

central part of the area and empties into the Wabash River south

of Vincennes, Indiana.

Geology

This area is covered almost entirely with Wisconsin loess.

The loess can be more than 7 feet (2 meters) thick on stable

summits. On the steeper slopes, it is thin or does not occur. The

loess throughout the area is underlain dominantly by glacial

till. Wisconsin outwash, alluvial deposits, and sandy eolian

material are on some of the stream terraces and on dunes along

the major tributaries in the area. The loess and glacial drift are

underlain by Pennsylvanian-age bedrock. Bedrock outcrops are

common in the walls of the valleys along the Wabash and Ohio

Rivers and at the base of some steep slopes along minor streams

and drainageways.

Climate

The average annual precipitation in most of this area is 40 to

47 inches (1,015 to 1,195 millimeters). About 60 percent of the

precipitation falls during the freeze-free period. Most of the

rainfall occurs as high-intensity, convective thunderstorms in

summer. Snowfall is common in winter. The average annual

temperature is 53 to 57 degrees F (11 to 14 degrees C). The freezefree period averages 210 days and ranges from 200 to 225 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 3.1%; ground water, 0.6%

Livestock—surface water, 0.1%; ground water, 0.2%

Irrigation—surface water, 0.2%; ground water, 0.2%

Other—surface water, 93.1%; ground water, 2.6%

The total withdrawals average 855 million gallons per day

(3,235 million liters per day). About 4 percent is from ground

water sources, and 96 percent is from surface water sources. In

most years the supply of moisture is adequate for crop

production, but in some years yields are reduced by drought,

especially on the sandy soils. The many springs, streams, and

farm ponds in the area are additional sources of surface water.

Some water for livestock is stored in small ponds and reservoirs.

The larger rivers provide water for industrial and municipal

uses and for some limited irrigation. Also, water from the Ohio

River is used for cooling thermoelectric power plants in

Illinois. The Ohio River is a major transportation artery, and the

Ohio and Wabash Rivers are used for recreation. The surface

water in the area is suitable for almost all uses. Water quality is

a concern in sandy areas.

Abundant ground water occurs only in deposits of

unconsolidated sand and gravel along the Ohio River, the lower

White River, and the Wabash River. These aquifers provide

water for domestic use, livestock, municipal and industrial

needs, and some limited irrigation. The average values of total

dissolved solids are close to 500 parts per million (milligrams

per liter), and the water is very hard. The water in Indiana is

much lower in iron than the water in Illinois.

Away from the river valley deposits, the only source of

ground water in Illinois is the Pennsylvanian-Mississippian

aquifer. Water from this aquifer is very hard and has high

amounts of iron. The level of total dissolved solids is 500 to

3,000 parts per million (milligrams per liter). In Indiana, the

only source of ground water outside the river valleys is in

isolated lenses of sand and gravel buried in older glacial till.

This water is very hard and high in content of iron, but it has

lower levels of total dissolved solids than the water in the other

aquifers. The low quantities of ground water from these aquifers

are used primarily for domestic purposes and for watering

livestock.

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, Inceptisols, and Mollisols. The soils in the area have a

mesic soil temperature regime, a udic or aquic soil moisture

regime, and dominantly mixed or smectitic mineralogy. The

soils are very deep, poorly drained to excessively drained, and

loamy, silty, or clayey.

Nearly level Endoaqualfs (Iva series) and Argiaquolls

(Ragsdale series) formed in loess on broad upland summits and

flats. Nearly level to steep Hapludalfs (Alford, Iona, Muren,

Stoy, and Sylvan series) and Fragiudalfs (Hosmer series)

formed in loess on uplands. Hapludalfs (Alvin, Bloomfield, and

Princeton series) and Argiudolls (Ade series) formed in sandy

eolian material in areas of dunes on uplands and stream

terraces. Steep and very steep Hapludalfs (Hickory series)

formed in Illinoian till along the major streams and dissected

upland drainageways. Hapludalfs (Wellston series) formed in

siltstone or sandstone residuum on strongly sloping to steep

side slopes underlain by bedrock. The soils in the major stream

valleys include Hapludolls (Carmi series), Argiudolls (Elston

series), and Hapludalfs (Skelton series), all of which formed in

outwash on nearly level to moderately sloping stream terraces

and outwash plains. Endoaquolls (Montgomery series),

Endoaquepts (Zipp series), Epiaqualfs (McGary series), and

Hapludalfs (Shircliff and Markland series) formed in clayey

lacustrine sediments on nearly level to strongly sloping

lacustrine terraces or lake plains. Endoaquepts (Evansville

series), Endoaquolls (Patton series), and Hapludalfs (Henshaw

and Uniontown series) formed in silty sediments on terraces and

lake plains.
of the United States 365

Endoaquolls (Beaucoup and Wabash series), Hapludolls

(Armiesburg, Landes, and Tice series), Eutrudepts (Nolin

series), and Endoaquepts (Petrolia series) formed in alluvium on

nearly level, broad flood plains. Fluvaquents (Birds and

Wakeland series) and Eutrudepts (Haymond and Wilbur series)

are along the smaller upland drainageways. Udorthents

(Bethesda, Fairpoint, Nawakwa, and Tapawingo series) and

Udarents (Hollybrook, Minnehaha, and Swanwick series)

formed in regolith from surface-mining operations.

Biological Resources

The uplands in this area support natural hardwoods. Oak,

hickory, and sugar maple are the dominant species. Big

bluestem, little bluestem, and scattered oak trees grow on some

sites. The lowlands support mixed forest vegetation, mainly

elm, cottonwood, river birch, ash, silver maple, sweetgum,

sycamore, pin oak, pecan, and willow. Sedge and grass

meadows and scattered trees are on some lowlands.

Some of the major wildlife species in this area are whitetailed deer, coyote, gray fox, red fox, beaver, raccoon, skunk,

muskrat, opossum, mink, rabbit, fox and gray squirrels, Canada

goose, bald eagle, turkey vulture, turkey, ruffed grouse,

woodcock, great horned owl, wood duck, pileated and redbellied woodpeckers, ring-necked pheasant, and bobwhite quail.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 69%

Grassland—private, 6%

Forest—private, 13%

Urban development—private, 6%

Water—private, 3%

Other—private, 3%

Most of this area is in privately owned farms, which produce

both cash-grain crops and livestock. The less sloping soils are

used for dry-farmed corn for grain and for soybeans. Some small

grains, such as winter wheat and grain sorghum, also are grown

in the area. A small acreage is used for specialty crops, such as

vegetables, melons, potatoes, and apple and peach orchards.

The grassland in the area supports introduced and native

grasses. About 13 percent of the area is forested. Surface coal

mines make up a small acreage of this MLRA.

The major soil resource concerns are wind erosion, water

erosion, flooding, wetness, a limited available water capacity,

and maintenance of the content of organic matter and

productivity of the soils. Conservation practices on cropland

generally include surface and subsurface drainage systems, crop

residue management, filter strips, cover crops, and nutrient and

pest management. Woodland management practices, such as

exclusion of grazing and timber stand improvement, are

important for timber production. 

Figure 115B-1: Location of MLRA 115B in Land Resource Region M.

115B—Central Mississippi Valley Wooded

Slopes, Western Part

This area (shown in fig. 115B-1) is in Missouri (78 percent)

and Illinois (22 percent). It makes up about 8,085 square miles

(20,955 square kilometers). It includes the towns or cities of

Cape Girardeau, Columbia, Fayette, Fulton, Jackson, Jefferson

City (the capital of Missouri), Ste. Genevieve, St. Louis, and

Washington, Missouri, and East St. Louis, Edwardsville, and

Chester, Illinois. Interstates 44, 55, 64, and 70 cross parts of

this area. The Gateway Arch National Memorial in St. Louis

and the Cahokia Mounds historical site are along the banks of

the part of the Mississippi River in this MLRA. The Daniel

Boone Memorial State Forest is in the part of the MLRA in

Missouri. The Shawnee National Forest is in the part in

Illinois.

Physiography

This area straddles the borders of five different

physiographic regions. The northern one-fifth of the area in

Missouri is in the glaciated Dissected Till Plains Section

(locally known as the Springfield Plain) of the Central Lowland

Province of the Interior Plains. The western end in Missouri is

in the Osage Plains Section of the same province and division.

The southern four-fifths of the area in Missouri is in the

Springfield-Salem Plateaus Section of the Ozark Plateaus
366 Major Land Resource Areas

Province of the Interior Highlands. The northeast part of the

area in Illinois is in the Till Plains Section of the Central

Lowland Province of the Interior Plains. The southeast corner of

the MLRA is in the Highland Rim Section (locally known as

the Shawnee Hills Section) of the Interior Low Plateaus

Province of the Interior Plains.

This area consists mainly of the deeply dissected, loesscovered hills bordering the Missouri and Mississippi Rivers,

their adjacent flood plains, and several relatively smooth, loessmantled karst plains. It wraps around the northeast corner of the

Ozark Uplift. The nearly level to very steep uplands are

dissected by both large and small tributaries of the Mississippi

River. Well defined valleys with broad flood plains and

numerous stream terraces are along the major streams and rivers.

The flood plains along the smaller streams are narrow. Broad

summits are nearly level to gently sloping. Karst topography is

common in this MLRA. The well developed karst areas have

hundreds of sinkholes, caves, springs, and losing streams. In the

St. Louis area, many of the karst features have been obliterated

by urban development. Elevation ranges from 320 feet (100

meters) on the southernmost flood plain along the Mississippi

River to 1,020 feet (310 meters) on the highest ridges. Local

relief is mainly 10 to 50 feet (3 to 15 meters), but it is as much

as 50 to 100 feet (15 to 30 meters) along drainageways and

streams. Also, the bluffs along the Mississippi River are

generally 200 to 350 feet (60 to 105 meters) above the floor of

the river valley.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Lower Missouri (1030), 49 percent; Upper MississippiKaskaskia-Meramec (0714), 41 percent; Upper Mississippi-Salt

(0711), 7 percent; and Gasconade-Osage (1029), 3 percent. The

Mississippi River flows through this area, forming the

boundary between Illinois and Missouri. The Kaskaskia,

Muddy, and Meramec Rivers empty into the Mississippi River

in the area. The Missouri River flows eastward through the

northern part of the area and empties into the Mississippi River

north of St. Louis. The Osage, Loutre, and Gasconade Rivers

empty into the Missouri River in this MLRA.

Geology

The uplands in this area are covered almost entirely with

Wisconsin loess. The loess is thick on stable summits. On the

steeper slopes, it is thin or does not occur. The loess in the

northeastern part of the MLRA is underlain by Illinoian glacial

drift, the dominant drift in Illinois. Wisconsin outwash deposits,

alluvium, and sandy eolian material are on some of the stream

terraces along the major tributaries in the area. The glacial

deposits are underlain by several bedrock systems. The

Mississippian System is the most extensive. Cherty dolostone

and limestone are the most common rock types in this system.

The Ordovician System is most common in more dissected

areas and consists mostly of sandstone, dolostone, and

limestone. Shale, sandstone, limestone, and coal in the

Pennsylvanian System occur in the northeastern part of the

MLRA, in both Illinois and Missouri. Bedrock outcrops are

common on the bluffs along the Mississippi River and its major

tributaries and at the base of steep slopes along minor streams

and valleys. Karst areas have formed where Mississippian or

Ordovician limestone is near the surface. Many limestone and

dolomite quarries are throughout the MLRA, and silica sand for

industrial uses in glass and abrasives is mined from the

Ordovician St. Peter Sandstone Formation in Missouri.

Climate

The average annual precipitation in most of this area is 38 to

48 inches (965 to 1,220 millimeters). About 60 percent of the

precipitation falls during the freeze-free period. Most of the

rainfall occurs as high-intensity, convective thunderstorms in

summer. Snowfall is common in winter. The average annual

temperature is 53 to 57 degrees F (12 to 14 degrees C). The

freeze-free period averages 205 days and ranges from 185 to

230 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 18.4%; ground water, 1.8%

Livestock—surface water, 0.4%; ground water, 0.1%

Irrigation—surface water, 0.0%; ground water, 0.2%

Other—surface water, 77.3%; ground water, 1.8%

The total withdrawals average 1,685 million gallons per day

(6,380 million liters per day). About 4 percent is from ground

water sources, and 96 percent is from surface water sources. In

most years the supply of moisture is adequate for crop

production, but in some years yields are reduced by drought.

Surface water is abundant in this MLRA. Water for livestock is

stored in small ponds and reservoirs. The larger rivers provide

water for public supply, industrial and municipal use, and some

limited irrigation. Water from the two large rivers also is used

for cooling thermoelectric power plants in Missouri. A growing

number of lakes are being constructed in areas of urban

development, especially in the St. Louis and Columbia,

Missouri, areas. The Mississippi and Missouri Rivers are major

transportation arteries and are used for recreation. Both rivers

carry large sediment loads and have low-quality water. The

waterflow is regulated by dams in the upper reaches of both

rivers. Generally, the flow is highest in May and June and

lowest in winter. Although most areas along the Missouri and

Mississippi Rivers are protected by a levee system, flooding

remains a major concern. The quality of surface water and

ground water is a concern in karst areas and in urban areas. The

quality is degraded by pesticides and nutrients in agricultural

runoff.
of the United States 367

This area has abundant ground water in deposits of

unconsolidated sand and gravel along the Mississippi River,

the lower reaches of the Meramac River, and the Missouri River.

These aquifers provide water for domestic use, livestock,

municipal and industrial needs, and some limited irrigation.

The average values of total dissolved solids are close to 500

parts per million (milligrams per liter), but the water is very

hard and may have high levels of iron. Away from the river

valley deposits in Illinois, ground water can be obtained from

the Pennsylvanian-Mississippian and Shallow Dolomite

aquifers. The water from these aquifers is similar in quality to

that in the river valley deposits, but the water in the Shallow

Dolomite aquifer has lower levels of iron. Away from the river

valley deposits in Missouri, ground water can be obtained from

the Ozark aquifer, which is south of the Missouri River, and the

Kimmswick-Potosi aquifer, which is north of the river. Both of

these aquifers consist of dolomite with some sandstone beds.

Their water has median levels of total dissolved solids that are

less than 500 parts per million (milligrams per liter). The water

is hard but is not typically high in iron. Because of the karst

topography, contaminated water from surface activities has

created some local water-quality problems in these bedrock

aquifers.

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, Inceptisols, and Mollisols. The soils in the area have a

mesic soil temperature regime, a udic or aquic soil moisture

regime, and dominantly mixed or smectitic mineralogy. The

soils are very shallow to very deep, poorly drained to

excessively drained, and loamy, silty, or clayey.

Gently sloping to depressional Albaqualfs (Marine, Mariosa,

and Pierron series), Hapludalfs (Marion series), and

Endoaqualfs (Caseyville series) formed in loess on broad

upland summits and flats. Gently sloping to steep Hapludalfs

(Winfield, Menfro, Hatton, Wrengart, and Stookey series)

formed in loess on uplands. Steep and very steep Hapludalfs

(Hickory series) formed in Illinoian till along the major streams

and dissected upland drainageways in the eastern part of this

MLRA. Hapludalfs (Freeburg series) and Endoaqualfs

(Moniteau series) formed in silty alluvium on terraces. The

major stream valleys also have soils that formed in bedrock

residuum and colluvium in steep or very steep areas on

uplands. Hapludalfs (Minnith, Neotoma, Pevely, and Wellston

series) and Paleudalfs (Holstein series) formed in siltstone or

sandstone residuum. Paleudalfs (Goss series) and Lithic

Hapludolls (Gasconade and Moko series) formed in limestone

and dolostone residuum. Endoaquolls (Booker, Fults, Ambraw,

Beaucoup, and Darwin series), Hapludolls (Landes, Tice, and

Medway series), and Endoaquepts (Karnak series) formed in

alluvium on nearly level, broad flood plains. The major soils on

the flood plain along the Missouri River are Udifluvents (Blake

and Haynie series), Fluvaquents (Waldron series), and

Udipsamments (Hodge and Sarpy series). Fluvaquents

(Wakeland series), Eutrudepts (Haymond and Wilbur series),

and Hapludolls (Dameron and Cedargap series) are along the

smaller upland drainageways. Udorthents (Harvester series) are

the major soils in urban areas.

Biological Resources

The soils on uplands support natural hardwoods. Oak,

hickory, and sugar maple are the dominant species. Big

bluestem, little bluestem, and scattered oak and eastern redcedar

trees grow on some sites. The soils on lowlands support mixed

forest vegetation, mainly elm, cottonwood, river birch, ash,

silver maple, sweetgum, sycamore, pin oak, pecan, and willow.

Sedge and grass meadows and scattered trees are on some

lowland sites.

Some of the major wildlife species in this area are whitetailed deer, coyote, gray fox, red fox, beaver, raccoon, skunk,

muskrat, opossum, mink, rabbit, fox squirrel, gray squirrel,

Canada goose, bald eagle, turkey vulture, turkey, ruffed grouse,

woodcock, great horned owl, wood duck, pileated woodpecker,

red-bellied woodpecker, ring-necked pheasant, and bobwhite

quail.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 32%

Grassland—private, 18%; Federal, 1%

Forest—private, 28%; Federal, 1%

Urban development—private, 15%

Water—private, 3%

Other—private, 2%

Most of this area is in privately owned farms, which produce

both cash-grain crops and livestock. The less sloping soils are

used for dry-farmed corn for grain and for soybeans. Some small

grains, such as winter wheat and grain sorghum, also are grown

in the area. A small acreage is used for specialty crops, such as

vegetables, Christmas trees, grape vineyards, and apple and

peach orchards. The grassland in the area supports introduced

and native grasses. Almost one-third of the area is forested.

The major resource concerns are water erosion, flooding,

wetness, a limited available water capacity, maintenance of the

content of organic matter and productivity of the soils, and

surface water quality. Conservation practices on cropland

generally include systems of crop residue management

(especially no-till systems), cover crops, terraces and grassed

waterways, windbreaks, vegetative wind barriers, and pest and

nutrient management. Woodland management practices, such

as exclusion of grazing and timber stand improvement, are

important for timber production. 
368 Major Land Resource Areas

Figure 115C-1: Location of MLRA 115C in Land Resource Region M.

115C—Central Mississippi Valley Wooded

Slopes, Northern Part

This area (shown in fig. 115C-1) is in Illinois (73 percent),

Missouri (21 percent), and Iowa (6 percent). It makes up about

13,650 square miles (35,375 square kilometers). The “Quad

Cities” of Moline and Rock Island, Illinois, and Bettendorf and

Davenport, Iowa, are in the northwest tip of this area. The area

also includes Muscatine, Burlington, and Fort Madison, Iowa;

Hannibal, Missouri; and Peoria, Canton, Macomb, and Quincy,

Illinois. Interstates 74 and 88 end in the Quad Cities, and

Interstate 80 cuts across the northern end of the area. Interstate

72 crosses the central part of the area from Jacksonville, Illinois,

to Hannibal, Missouri. The area has a number of State parks and

national wildlife refuges, especially along the Mississippi

River. Small parcels of State forests are in the part of the MLRA

in Illinois.

Physiography

Most of this area is in the Till Plains Section of the Central

Lowland Province of the Interior Plains. The western part of the

area in Missouri is in the Dissected Till Plains Section of the

same province and division. The southern edge is in the

Springfield-Salem Plateaus Section of the Ozark Plateaus

Province of the Interior Highlands. Locally, most of this area is

known as the glaciated Galesburg Plain and Springfield Plain,

and the southern edge is in an area known as the Lincoln Hills

and Salem Plateau. The nearly level to very steep uplands in

this MLRA are dissected by both large and small tributaries of

the Mississippi River. Well defined valleys with broad flood

plains and numerous stream terraces are along the major

streams and rivers. The flood plains along the smaller streams

are narrow. Broad summits are nearly level to gently sloping.

Elevation ranges from 420 feet (130 meters) on the

southernmost flood plain along the Mississippi River to 885 feet

(270 meters) on the highest ridges. Local relief is mainly 10 to

20 feet (3 to 6 meters), but it can be 50 to 100 feet (15 to 30

meters) along drainageways and streams. Also, the bluffs along

the Illinois and Mississippi Rivers are as much as 250 feet (75

meters) above the valley floors.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Lower Illinois (0713), 54 percent; Upper Mississippi-Salt

(0711), 32 percent; Upper Mississippi-Iowa-SkunkWapsipinicon (0708), 10 percent; and Rock (0709), 4 percent.

The Mississippi River flows through this area, forming the

boundaries between Iowa and Illinois and between Missouri

and Illinois. Lock and Dam Numbers 14 through 25 form lakes

on the Mississippi River from Clinton, Iowa, to Hannibal,

Missouri. The Illinois River flows through the eastern part of

this area. The La Moine, Spoon, Mackinaw, and Sangamon

Rivers are major tributaries to the Illinois River in the area. The

Rock, Henderson, Edwards, and Bear Rivers empty into the

Mississippi from the Illinois side in this area. The

Wapsipinicon, Iowa, Skunk, and Des Moines Rivers from the

Iowa side and the Fox, Wyaconda, North and South Fabius,

Salt, and Cuivre Rivers from the Missouri side also empty into

the Mississippi River.

Geology

The uplands in this area are covered almost entirely with

Wisconsin loess. The loess is thick on stable summits. On the

steeper slopes, it is thin or does not occur. The loess is

underlain dominantly by glacial drift consisting of distinct till

units. Illinoian glacial drift is the dominant drift in Illinois and

is of minor extent in Iowa. Pre-Illinoian drift is in the parts of

this MLRA in Iowa and Missouri and to a minor extent in the

western part of Illinois, in Hancock, Adams, and Pike Counties.

Unglaciated areas are in the southwestern portion of the part of

the MLRA in Illinois. Wisconsin outwash deposits and sandy

eolian material are on some of the stream terraces along the

major tributaries. The glacial drift and loess deposits are

underlain by several bedrock systems. The Cretaceous System

is of minor extent, occurring only in Pike and Adams Counties,

Illinois. The Pennsylvanian System occurs in the eastern part of

the MLRA. The Mississippian System occurs along the

Mississippi and Illinois Rivers. The Silurian System occurs in

the northern and southern parts of the area. The Devonian

System occurs only in the northern part of the area, and the
of the United States 369

Ordovician System occurs only in the southern part. Bedrock

outcrops are common on the bluffs along the Mississippi River

and its major tributaries and at the base of steep slopes along

minor streams and drainageways.

Climate

The average annual precipitation in most of this area is 34 to

40 inches (865 to 1,015 millimeters). Two-thirds or more of the

precipitation falls during the freeze-free period. Most of the

rainfall occurs as high-intensity, convective thunderstorms in

summer. Snowfall is common in winter. The average annual

temperature is 48 to 55 degrees F (9 to 13 degrees C). The

freeze-free period averages 200 days and ranges from 180 to

215 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 3.8%; ground water, 0.6%

Livestock—surface water, 0.1%; ground water, 0.1%

Irrigation—surface water, 0.1%; ground water, 1.1%

Other—surface water, 92.9%; ground water, 1.4%

The total withdrawals average 3,555 million gallons per day

(13,455 million liters per day). About 3 percent is from ground

water sources, and 97 percent is from surface water sources. In

most years the supply of moisture is adequate for crop

production, but in some years yields are reduced by drought.

Surface water is abundant in this MLRA. Water for livestock is

stored in small ponds and reservoirs. The larger rivers provide

water for public supply, industrial and municipal use, and some

limited irrigation. Water from the Mississippi River also is used

for cooling thermoelectric power plants in the three States in

this area. The Mississippi River is a major transportation artery

and is used for recreation. Most of the large rivers in the area

carry heavy sediment loads and have low-quality water. The

waterflow is regulated by dams in the upper reaches of most

rivers. Generally, the flow is highest in May and June and

lowest in winter. Although most areas along the Mississippi

River are protected by a levee system, flooding remains a major

concern. Water quality is a concern in karst areas and in urban

areas. Also, it is degraded by agricultural runoff.

Abundant ground water occurs in deposits of

unconsolidated sand and gravel along the Mississippi River,

the Illinois River, and other large rivers throughout this area.

These aquifers provide water for domestic use, livestock,

municipal and industrial needs, and some limited irrigation.

The average values of total dissolved solids are close to 500

parts per million (milligrams per liter), and the water is very

hard and may have high levels of iron. Away from the river

valley deposits in Illinois, ground water can be obtained from

the Pennsylvanian-Mississippian and Shallow Dolomite

aquifers. The water from these aquifers is similar in quality to

the water in the river valleys, but the Shallow Dolomite aquifer

has lower levels of iron. Areas away from the river valley

deposits in Missouri have two sources of ground water. A

glacial drift aquifer lies over the Pennsylvanian-Mississippian

aquifer in these areas. Well yields are generally low from both

these aquifers, but rural landowners rely on them for domestic

and livestock water. The water quality varies considerably. The

level of total dissolved solids can be 500 to 3,000 parts per

million (milligrams per liter). The water is hard and is typically

high in iron. Because of karst topography in the southern end

of this area, contaminated water from surface activities has

created some local water-quality problems in the

Pennsylvanian-Mississippian aquifer.

In the part of this MLRA in Iowa, rural landowners and some

farmers and small communities rely on ground water from the

Silurian-Devonian and Jordan aquifers. The Silurian-Devonian

aquifer is most accessible just north of the middle of the part of

this MLRA in Iowa, whereas the Jordan aquifer underlies all of

this part of the MLRA. The Jordan aquifer is the most

extensively used aquifer in Iowa. It consists of sandstone and

dolomite of Ordovician and Cambrian age. Well yields from

this aquifer are very high, and the water from the aquifer is

suitable for most uses. The median level of total dissolved

solids, however, typically exceeds 800 parts per million

(milligrams per liter), and radium-226 levels can exceed the

national standard for drinking water. The Silurian-Devonian

aquifer consists of limestone and dolomite. It is close to the

surface in the part of the MLRA in Iowa, and it has the best

water quality of all the principal aquifers in Iowa. Where this

aquifer is buried by younger bedrock deposits, the level of total

dissolved solids and naturally high levels of sulfate limit use of

the water. The Jordan and Silurian-Devonian aquifers provide

water for domestic use, livestock, irrigation, public and

municipal supply, and industry.

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, Inceptisols, and Mollisols. The soils in the area have a

mesic soil temperature regime, a udic or aquic soil moisture

regime, and dominantly mixed or smectitic mineralogy. The

mesic soil temperature regime occurs in two regions in this

MLRA—cool mesic areas and warm mesic areas. The soils in

the MLRA are very shallow to very deep, poorly drained to

excessively drained, and loamy, silty, or clayey.

Nearly level Endoaquolls (Sable and Virden series), nearly

level to depressional Albaqualfs (Rushville and Denny series),

and nearly level Argiudolls (Ipava series) and Endoaqualfs

(Keomah series) formed in loess on broad upland summits and

flats. Gently sloping to sloping Argiudolls (Osco and Tama

series) and gently sloping to steep Hapludalfs (Fayette, Rozetta,

Seaton, Winfield, and Menfro series) formed in thick deposits of

loess on uplands. Sloping to steep Hapludalfs (Elco and
370

Hickory series) formed in Illinoian till or paleosols along the

major streams and dissected upland drainageways. Sloping to

steep Hapludalfs (Lindley and Keswick series) formed in preIllinoian till along the major streams and dissected upland

drainageways. Hapludolls (Sparta series), Argiudolls (Onarga

and Plano series), and Udipsamments (Plainfield series) are on

gently sloping to strongly sloping stream terraces along the

major streams. The major stream valleys also have soils that

formed in bedrock residuum and colluvium in strongly sloping

to very steep areas on uplands. Hapludalfs (Marseilles series)

and Dystrudepts (Gosport series) formed in shale residuum,

Paleudalfs (Baylis and Goss series) and Hapludolls (Elizabeth

series) formed in limestone residuum, and Dystrudepts

(Judyville series) formed in sandstone residuum. Hapludolls

(Lacrescent series) formed in limestone colluvium. Moderately

sloping to very steep Hapludalfs (El Dara series) formed in

Cretaceous deposits.

Endoaquolls (Beaucoup, Otter, and Sawmill series) and

Hapludolls (Huntsville, Ross, and Tice series) formed in

alluvium on nearly level, broad flood plains. Fluvaquents

(Wakeland series), Udifluvents (Orion series), and Hapludolls

(Lawson and Radford series) are along the smaller upland

drainageways.

Biological Resources

The soils on uplands in this area support natural hardwoods.

Oak, hickory, and sugar maple are the dominant species. Big

bluestem, little bluestem, and scattered oak trees grow on some

sites. The soils on lowlands support mixed forest vegetation,

mainly elm, cottonwood, river birch, ash, silver maple, and

willow. Sedge and grass meadows and scattered trees are on

some lowland sites.

Some of the major wildlife species in this area are whitetailed deer, coyote, gray fox, red fox, beaver, raccoon, skunk,

muskrat, opossum, mink, cottontail, fox squirrel, gray squirrel,

Canada goose, bald eagle, turkey vulture, turkey, ruffed grouse,

woodcock, great horned owl, wood duck, pileated woodpecker,

red-bellied woodpecker, ring-necked pheasant, and bobwhite

quail.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 59%

Grassland—private, 11%

Forest—private, 17%; Federal, 1%

Urban development—private, 6%

Water—private, 4%

Other—private, 2%

Most of this area is in privately owned farms, which produce

both cash-grain crops and livestock. The less sloping soils are

used for dry-farmed corn for grain and for soybeans. Some small

grains, such as winter wheat and oats, also are grown in the area.

Some areas on broad stream terraces and outwash plains are

irrigated. A small acreage is used for specialty crops, such as

watermelons, pumpkins, and orchards. The grassland in the area

supports introduced and native grasses. About 18 percent of the

area is forested. Although not occupying a large acreage,

surface-mined areas that have been or are currently being

reclaimed occur in the northeastern part of the MLRA.

The major soil resource concerns are wind erosion, water

erosion, flooding, wetness, a limited available water capacity,

and maintenance of the content of organic matter and

productivity of the soils. Conservation practices on cropland

generally include systems of crop residue management

(especially no-till systems), cover crops, windbreaks, vegetative

wind barriers, and pest and nutrient management. Woodland

management practices, such as grazing exclusion

and timber stand improvement, are important for timber

production. 
371

Figure N-1: Location of Land Resource Region N.

N—East and Central Farming and Forest

Region

This region (shown in fig. N-1) is in Kentucky (16 percent),

Missouri (13 percent), Tennessee (13 percent), Arkansas (11

percent), West Virginia (9 percent), Pennsylvania (8 percent),

Alabama (6 percent), Ohio (6 percent), Oklahoma (5 percent),

Virginia (4 percent), North Carolina (3 percent), Indiana (3

percent), Georgia (2 percent), and Illinois (1 percent) and in

very small areas in Kansas, Maryland, New York, and South

Carolina. It makes up 236,415 square miles (612,645 square

kilometers).

Diversity of topography and climate gives rise to a wide

range of natural ecosystems and limits the amount of land

available for production agriculture. The topography ranges

from undulating hills in the Kentucky Bluegrass region to steep,

mountainous terrain in the Appalachians (fig. N-2). The climate

ranges from hot and humid with modest snowfall in the western

part of the region to more than 100 inches (2,540 millimeters)

of annual snowfall in spruce forests in the eastern part. The

mean annual precipitation in most of the region is 40 to 59

inches (1,015 to 1,500 millimeters), but the southern, highelevation parts of the Blue Ridge may receive as much as 119

inches (3,025 millimeters). The mean annual air temperature in

most of the region is 52 to 59 degrees F (11 to 15 degrees C).

The freeze-free period generally ranges from 180 to 235 days,

but it is considerably shorter in the high-elevation areas in

North Carolina, Virginia, and West Virginia. The mean annual

air temperature and the length of the freeze-free period increase

from north to south and with decreasing elevation.

The physiography in the part of this region east of the

Mississippi River is varied and consists of gently rolling terrain

on level-bedded limestone in the Kentucky Bluegrass and

Highland Rim areas. Moving eastward, the topography

becomes progressively more dissected and hilly. The

Appalachian Plateau, stretching from central Pennsylvania to

northern Georgia, grades from a dissected plateau to a rugged

band of mainly forested mountains and high hills underlain by

shale, sandstone, coal, and some limestone. The Valley and

Ridge features long, linear forested ridges and cropland in the

valleys. The bedrock geology is faulted and folded shale,

sandstone, and limestone. The Blue Ridge makes up the eastern

edge of the region. It consists mainly of rugged mountains
372 Major Land Resource Areas

formed from igneous and metamorphic rocks. West of the

Mississippi River, the Ozarks are a slightly dissected to deeply

dissected plateau typically underlain by limestone, sandstone,

and shale bedrock. Igneous rocks are exposed in a small area in

southeast Missouri. Elevation ranges from 300 to 6,600 feet (90

to 2,010 meters) overall. West of the Mississippi River,

elevation ranges from 300 to 2,750 feet (90 to 840 meters) and

local relief ranges from 100 feet (30 meters) in the St. Francois

Knobs and Basins to 800 feet (245 meters) in the Ozark

Highland. East of the Mississippi River, elevation ranges from

330 to 6,600 feet (100 to 2,010 meters) and is highest in the

Southern Blue Ridge. Local relief ranges from 10 to 50 feet (3

to 15 meters) in southern Indiana to 1,000 to 3,000 feet (305 to

915 meters) in western North Carolina.

The total withdrawals of freshwater in this region average

about 30,935 million gallons per day (119,720 million liters

per day). About 93 percent is from surface water sources, and 7

percent is from ground water sources. This region is one of six

land resource regions that use more than 30,000 million gallons

(113,550 million liters) of water daily. About 89 percent of the

total water used is for cooling thermoelectric power plants or

for mining or industry.

The soils in this region are dominantly Alfisols, Entisols,

Inceptisols, or Ultisols. In the Ozarks, Hapludalfs and

Paleudults formed in material weathered dominantly from

limestone and cherty limestone. Hapludults and Dystrudepts

formed in shale and sandstone residuum. Paleudults and

Hapludults typically formed in colluvium. Most of the soils in

the middle third of the region are Hapludalfs that formed in

limestone residuum or loess. The soils in the eastern third of the

region are dominantly Hapludults and Dystrudepts that formed

in shale and sandstone residuum. Some Hapludalfs formed in

calcareous material. In the high mountains, the soils are

dominantly Dystrudepts and Hapludults that formed in material

weathered from igneous and metamorphic rocks. The soils in

the region have a thermic, mesic, or frigid soil temperature

regime, depending on latitude and elevation, and have a udic

soil moisture regime.

About 93 percent of the land in this region is privately

owned. The native vegetation generally consists of deciduous

forests. At the highest elevations, however, coniferous forests

and glades are evident. Forestry is an important industry.

Oak, yellow-poplar, and pine are the dominant trees harvested.

The array of crops grown is diverse and includes cotton,

soybeans, corn, and wheat. The major management concerns in

areas of forestland are the erosion resulting from harvest

practices and maintenance of forest productivity. The concerns

on cropland include maintenance of the productivity of the

soils, erosion control, and prevention of ground-water

contamination. 

Figure N-2: An area of Land Resource Region N.
of the United States 373

Figure 116A-1: Location of MLRA 116A in Land Resource Region N.

116A—Ozark Highland

This area (shown in fig. 116A-1) is in southern Missouri (72

percent), northern Arkansas (23 percent), and northeastern

Oklahoma (5 percent). It makes up about 32,845 square miles

(85,110 square kilometers). West Plains, Branson, and Poplar

Bluff, Missouri, and Bentonville, Mountain Home, and

Springdale, Arkansas, are the major towns in the area. Interstate

44 cuts across the area diagonally from St. Louis to Springfield,

Missouri. The area has several large reservoirs. The major ones

are the Lake of the Ozarks, Truman Lake, Table Rock Lake,

Norfolk Lake, Bull Shoals Lake, and Beaver Lake. The Mark

Twain National Forest manages the largest part of the public

lands in Missouri, and parts of the Ozark National Forest are in

Arkansas. These forests occur in this MLRA. The Ozark

National Scenic Riverways is the largest national park in the

area. The Pea Ridge National Military Park in Arkansas and

Fort Leonard Wood, a major military base in Missouri, are in

this area.

Physiography

This area is in the Springfield-Salem Plateaus Section of the

Ozark Plateaus Province of the Interior Highlands. The

landscape ranges from highly dissected, steeply sloping wooded

hills and narrow, gravelly valleys in the central and southern

parts of the area to gently rolling prairie-like uplands in the

northern part. Soluble carbonate rocks are responsible for a well

developed karst topography in the southern part of the area.

This topography includes sinkholes, caves, dry valleys, box

valleys, and large springs. Elevation ranges from about 300 feet

(90 meters) on the southeast edge of the Ozark escarpment to

about 1,600 feet (490 meters) on the western side of the area.

Relief is generally 200 to 800 feet (60 to 245 meters). It is

highest in the southwestern part of the area. The geologic strata

generally are horizontally bedded, but with a slight dip to the

west and south away from the apex of the Ozark Uplift in

southeast Missouri.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Upper White (1101), 47 percent; Gasconade-Osage (1029), 25

percent; Upper Mississippi-Kaskaskia-Meramec (0714), 14

percent; Neosho-Verdigris (1107), 6 percent; Lower Arkansas

(1111), 4 percent; Lower Missouri (1030), 3 percent; and Lower

Mississippi-St. Francis (0802), 1 percent. The major rivers in

this area are the Osage, Gasconade, Current, Black, James,

White, and Buffalo Rivers. The Ozark and Eleven Point Rivers

in Missouri have been designated as National Scenic Rivers.

The Buffalo River is a National Scenic River in Arkansas, and

the Strawberry and Illinois Rivers are National Wild and Scenic

Rivers in Arkansas and Oklahoma, respectively. Streamflow is

highest in winter and spring.

Geology

This area has a variety of geologic formations. Most of the

bedrock consists of sedimentary rocks, including Ordovicianage dolostone and sandstone, Lower Mississippian-age

limestone and dolostone, and Pennsylvanian-age sandstone

and shale. Remnants of an ancient loess deposit ranging from

a few inches to several feet in thickness are on the nearly level

upland divides. The loess is thickest in the northern and

eastern parts of the area. Most of the exposed bedrock consists

of limestone and dolostone formations that have thick layers of

chert bedrock or chert fragments. The chert generally occurs in

long, wavy beds less than 1 foot thick. In some areas, however,

it occurs in massive layers more than 6 feet (2 meters) thick.

Several old and inactive geologic faults are in the area.

Climate

The average annual precipitation in almost all of this area is

38 to 45 inches (965 to 1,145 millimeters). It is as high as 49

inches (1,245 millimeters) in some small areas along the

extreme southeast and south edges of the area. About 57

percent of the annual precipitation falls during the 6 warmest

months of the year. Snow falls nearly every winter, but the snow

cover lasts for only a few days. The annual snowfall averages

about 12 inches (305 millimeters). The average annual

temperature is about 53 to 60 degrees F (12 to 16 degrees C).

The lower temperatures occur at the higher elevations in the

western part of the MLRA. The freeze-free period averages 210

days and ranges from 175 to 245 days. It is shortest at the

higher elevations along the western edge of the MLRA. The

longer freeze-free periods occur at the lower elevations.
374 Major Land Resource Areas

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 12.0%; ground water, 8.4%

Livestock—surface water, 3.1%; ground water, 2.9%

Irrigation—surface water, 1.6%; ground water, 5.9%

Other—surface water, 59.2%; ground water, 6.8%

The total withdrawals average 675 million gallons per day

(2,555 million liters per day). About 24 percent is from ground

water sources, and 76 percent is from surface water sources. In

most years precipitation is adequate for most agricultural uses,

but summer droughts of sufficient severity and duration to

reduce production are common. Streams, ponds, springs, and

lakes provide surface water for livestock. Karst areas are

common in much of the southern part of the MLRA, and many

stretches of headwater streams in this part of the MLRA are dry

or losing streams. This water flows to underground systems and

returns elsewhere as springs. Springs are numerous, and spring

flow is a major contributor to the base flow of many streams.

The major springs are Big, Blanchard, Greer, Alley, Mammoth,

and Round Springs. Large reservoirs in the area provide

hydroelectric power, flood control, and opportunities for

recreation.

Ground water is abundant in this area. The primary source is

the Ozark aquifer in Missouri and Arkansas. This aquifer

consists of consolidated dolomite with some minor beds of

sandstone. It is about 1,000 feet below the ground surface in

western Missouri. It has good-quality water, and it provides

water for public supply, irrigation, municipal and industrial

uses, and domestic use. Water in the Ozark aquifer has median

levels of total dissolved solids of 275 and 322 parts per million

(milligrams per liter) in Arkansas and Missouri, respectively. It

is hard or very hard but is not high in iron. Because of the karst

topography, contaminated water from surface activities has

created some local water-quality problems in this bedrock

aquifer. Hazardous waste, landfills, municipal and industrial

wastewater, and agricultural activities have caused some

bacteria and nitrate contamination.

The Roubidoux and Keokuk-Reeds Spring aquifers are in

this area. They occur only in a few counties in the northeast

corner of Oklahoma. These aquifers are the only source of water

for rural landowners and the small communities in this part of

the MLRA. The water is generally of good quality and is

suitable for most uses. The median level of total dissolved

solids is only 280 parts per million (milligrams per liter).

Chloride, sulfate, and fluoride levels, however, exceed the

national drinking water standards in some areas.

Soils

Most of the soils in this area are Alfisols or Ultisols. They

formed in material weathered from cherty limestone. Most areas

in the northern and eastern parts of the MLRA are partly

covered with a thin mantle of loess. Physical and chemical

weathering has caused the cherty limestone to disintegrate into

its least soluble components, which are chert and clay. The

chert remains in the form of angular fragments or wavy horizon

beds interstratified with layers of clay. Downslope movement

by gravitational creep and overland waterflow has altered the

cherty material in the upper part of some soils. In general, the

soils are shallow to very deep, moderately well drained to

excessively drained, and medium textured to fine textured.

The soil temperature regime is mesic bordering on thermic,

the soil moisture regime is udic, and mineralogy is mixed or

siliceous.

Many of the soils on nearly level to moderately sloping

upland divides are Paleudalfs (Gravois, Gepp, and Peridge

series), Fragiudalfs (Union, Viraton, and Wilderness series), or

Fragiudults (Captina, Scholten, and Tonti series). Many of the

soils on moderately sloping to steep side slopes in the uplands

are Hapludalfs (Gatewood, Mano, Ocie, and Wrengart series),

Hapludults (Bendavis, Bender, and Lily series), Paleudalfs

(Alred, Goss, and Rueter series), or Paleudults (Clarksville,

Coulstone, Noark, and Poynor series). Many of the soils in

glades are Mollisols (Gasconade, Knobby, and Moko series).

Many of the soils on terraces and the adjacent flood plains are

Hapludalfs (Razort, Secesh, and Waben series), Hapludolls

(Cedargap, Dameron, and Sturkie series), Paleudalfs (Britwater

and Pomme series), Eutrudepts (Gladden and Jamesfin series),

or Udifluvents (Midco and Relfe) series.

Biological Resources

Oak, hickory, and shortleaf pine are the major tree species in

the forested areas of this MLRA. Eastern redcedar is a common

invader in abandoned fields and in glades. Most of the less

sloping areas have been cleared and planted to cool-season

grasses. Fescue is the dominant introduced grass species. Glade

openings support warm-season grasses, primarily big bluestem,

Indiangrass, little bluestem, and dropseeds. Savanna restoration

projects are underway in the national and State forests and

parks.

Some of the major game species of wildlife are white-tailed

deer, eastern cottontail, raccoon, wood duck, wild turkey,

smallmouth bass, and largemouth bass.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 5%

Grassland—private, 32%; Federal, 1%

Forest—private, 48%; Federal, 6%

Urban development—private, 4%

Water—private, 2%; Federal, 1%

Other—private, 1%
of the United States 375

The public lands in this area are used for timber production

and for recreational activities. Most of the private lands are in

farms and ranches. Forage and grain are grown for beef, dairy

cattle, and other livestock. Raising cattle, both beef and dairy,

is one of the major industries in the area. Poultry production is

important in the southwestern part of the area. Specialized

farming includes vineyards and small orchards. The areas along

the Interstate 44 corridor and near the large lakes have a

growing service industry oriented to recreation and tourism.

Commercial and residential growth occurs mainly around the

large lakes, the major highways, and the Branson area.

The major resource concerns are the quality of both surface

and subsurface water; forest and grassland productivity, health,

and vigor; and streambank erosion. The important conservation

practices are forest stand improvement, prescribed grazing,

development of springs, riparian forest buffers, nutrient

management, and exclusion from use as needed. Figure 116B-1: Location of MLRA 116B in Land Resource Region N.

116B—Springfield Plain

This area (shown in fig. 116B-1) is dominantly in southwest

Missouri (95 percent) and extends for a short distance into the

northeast corner of Oklahoma (4 percent) and southeast Kansas

(1 percent). It makes up about 5,130 square miles (13,300

square kilometers). This is one of the fastest growing areas in

Missouri. The towns of Springfield, Carthage, and Joplin,

Missouri, are the major urban areas in the MLRA. They are

connected by Interstate 44, which runs in an east-west direction

through the center of the area. The birthplace of a famous

agricultural scientist is marked by the George Washington

Carver National Monument, in the western part of the area, near

Diamond, Missouri. The Wilson’s Creek National Battlefield,

near Springfield, is the site of a Civil War battle.

Physiography

This area is in the Springfield-Salem Plateaus Section of the

Ozark Plateaus Province of the Interior Highlands. It is in the

western part of the Ozark Uplift, which is commonly referred to

as the Springfield Plateau. It is primarily a smooth plain that is

slightly dissected along streams. The plain is underlain by

carbonate rocks. These formations are responsible for well

developed karst features in several places and also numerous

caves and springs. Elevation is about 1,000 feet (305 meters) in

the northern part of the area and increases to more than 1,700

feet (520 meters) on the eastern escarpment. Relief is generally

less than 150 feet (45 meters) but is as much as 250 feet (75

meters) along the eastern boundary of the area, where the

prominent Burlington Escarpment rises above the adjacent

Ozark Highlands.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Neosho-Verdigris (1107), 42 percent; Gasconade-Osage (1029),

36 percent; and Upper White (1101), 22 percent. Because it is

at a relatively high elevation, this area includes the headwaters

and upper reaches of streams that drain into adjacent regions.

These include the Sac River, which flows north into the Osage

River; the James River and Finley Creek, which flow south into

the White River; and Shoal Creek and the Spring River, which

drain most of the western part of the area westward into the

Neosho River. Stockton Lake is a large multipurpose reservoir

on the Sac River. Lake McDaniel and Lake Springfield provide

water for the city of Springfield.

Geology

Sedimentary rocks ranging from Mississippian-age

limestone to Pennsylvanian-age sandstone and shale underlie

this area. A layer of loess that is generally about 6 inches or less

thick covers most of the area. Erosion has removed much of the

original loess. On the nearly level upland divides, however,

remnants of the loess are 1 to 2 feet (0.3 to 0.7 meter) thick.

Most of the exposed bedrock consists of limestone formations

that have thick layers of chert bedrock or chert fragments. The

chert generally occurs in long, wavy beds less than 1 foot thick.

In some areas, however, it occurs in massive layers more than 6

feet (2 meters) thick. Although the bedrock strata appear to lie

horizontally, there is a regional dip to the west. The direction of

the dip is influenced mainly by the Ozark Uplift. The apex of

the uplift is in southeast Missouri, and the bedrock dips away

from the uplift. Historic lead and zinc mines in the

southwestern part of the MLRA have scarified large areas.

Tripoli, a chert powder used for polishing and for

manufacturing paint and paper, is mined in Newton County,

Missouri. High-calcium limestone is quarried, mostly near

Springfield and Joplin.
376 Major Land Resource Areas

Climate

The average annual precipitation in this area is 41 to 45

inches (1,040 to 1,145 millimeters). About 57 percent of the

annual precipitation falls during the 6 warmest months of the

year. Snow falls nearly every winter, but the snow cover lasts for

only a few days. The annual snowfall averages about 12 inches

(305 millimeters). The average annual temperature is about 55

to 58 degrees F (13 to 15 degrees C). The lower temperatures

occur at the higher elevations. The freeze-free period averages

210 days and ranges from 195 to 225 days. It is shortest at the

higher elevations.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 10.0%; ground water, 5.9%

Livestock—surface water, 0.5%; ground water, 0.2%

Irrigation—surface water, 0.3%; ground water, 0.9%

Other—surface water, 76.3%; ground water, 5.9%

The total withdrawals average 685 million gallons per day

(2,595 million liters per day). About 13 percent is from ground

water sources, and 87 percent is from surface water sources. In

most years the precipitation is adequate for crops and pasture,

but summer droughts of sufficient severity and duration to

reduce crop yields are common. Streams, ponds, springs, and

lakes provide surface water for most livestock. Springs are

numerous, and spring flow is a major contributor to the base

flow of many streams. The few large reservoirs in the area

provide flood control, opportunities for recreation, and part of

the water supply for large cities, such as Springfield. The

surface water is generally of good quality and is suitable for

most uses.

Ground water is very abundant in this area. The primary

source is the Ozark aquifer in Missouri. This aquifer consists of

consolidated dolomite with some minor beds of sandstone. It is

about 1,000 feet below the ground surface in western Missouri.

It has good-quality water, and it provides water for public

supply, irrigation, municipal and industrial uses, and domestic

use. Water in the Ozark aquifer has median levels of total

dissolved solids of 322 parts per million (milligrams per liter).

The water is hard or very hard but is not high in iron. Because

of the karst topography, contaminated water from surface

activities has created some local water-quality problems in this

bedrock aquifer. Hazardous waste from abandoned lead and

zinc mines, landfills, municipal and industrial wastewater, and

agricultural activities have caused some contamination by heavy

metals, bacteria, and nitrates.

The Roubidoux and Keokuk-Reeds Spring aquifers are in

this area. They occur only in a few counties in the northeast

corner of Oklahoma. They are the only sources of water for rural

landowners and the small communities in this part of the

MLRA. The water generally is of good quality and is suitable

for most uses. The median level of total dissolved solids is only

280 parts per million (milligrams per liter). Chloride, sulfate,

and fluoride levels, however, exceed the national drinking

water standards in some areas.

Soils

Most of the soils in this area are Alfisols, Ultisols, or

Mollisols. They formed in material weathered from cherty

limestone. This material is partly covered with a thin mantle of

loess. Physical and chemical weathering has caused the cherty

limestone to disintegrate into its least soluble components,

which are chert and clay. The chert remains in the form of

angular fragments or wavy horizon beds interstratified between

layers of clay. Downslope movement by gravitational creep and

overland waterflow has altered the cherty material in the upper

part of some soils. In general, the soils are moderately deep to

very deep, moderately well drained to well drained, and

medium textured to fine textured. The soil temperature regime

is typically mesic and extends slightly into thermic. The soil

moisture regime is udic. Mineralogy generally is mixed or

siliceous, but some soils are high in kaolinite.

Many of the soils on nearly level to moderately sloping

upland divides are Paleudolls (Newtonia and Wanda series),

Paleudalfs (Peridge series), Fragiudalfs (Creldon, Hoberg,

Keeno, and Viraton series), Fragiaqualfs (Bado and Gerald

series), Fragiudults (Captina, Needleye, Nixa, and Tonti series),

or Hapludalfs (Barden and Bolivar series). Many of the soils on

moderately sloping to steep side slopes in the uplands are

Paleudalfs (Bona, Goss, and Rueter series) or Paleudults

(Clarksville series). Many of the soils on terraces and the

adjacent flood plains are Hapludalfs (Razort, Secesh, and

Waben series), Hapludolls (Cedargap and Dapue series),

Paleudalfs (Pomme and Pembroke series), or Eutrudepts

(Jamesfin series).

Biological Resources

This is a transitional area between the oak-hickory forests to

the east and south and the bluestem prairie to the west and

north. The vegetation prior to settlement consisted mostly of

prairie grasses with timber along streams. The major native

grass species are big bluestem, little bluestem, Indiangrass, and

switchgrass. Most of the area is cleared and used for pasture or

cropland, but forests remain in the steepest areas. Fescue is the

dominant introduced grass species.

Some of the major wildlife species in the area are whitetailed deer, eastern cottontail, raccoon, wood duck, wild turkey,

smallmouth bass, and largemouth bass. Several prairie species,

such as black-tailed jackrabbits and prairie chickens, inhabit

small areas of the original tall grass prairie.
of the United States 377

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 20%

Grassland—private, 45%; Federal, 1%

Forest—private, 22%

Urban development—private, 8%

Water—private, 2%

Other—private, 2%

Farms and ranches make up most of this area. Forage and

grain are grown for beef, dairy cattle, and other livestock.

Raising cattle is one of the major industries in the area. The

area around Springfield is the leading dairy area in Missouri.

From the practice of keeping a few chickens on each farm, the

poultry business has developed into a very specialized

multimillion-dollar industry. Soybeans, winter wheat, and hay

are the major cash crops grown in the area. The loss of prime

farmland and farmland of statewide importance to urban

development is a concern, especially in the Springfield and

Joplin areas.

The major resource concerns are excessive nutrients and

organic material in surface water; conversion of farmland to

urban uses; ground-water pollution in areas of karst topography;

forest and pasture productivity, health, and vigor; inadequate

water sources for domestic animals; and the structure failure of

dams in areas of ponds and small lakes. The structure failure of

dams results from a high amount of kaolinitic clay in the

soils.

The conservation practices that are important in this area are

management of phosphorus from chicken litter applied to

cropland and pasture, forest stand improvement, prescribed

grazing, development of springs, riparian forest buffers, and

construction of ponds. 

Figure 116C-1: Location of MLRA 116C in Land Resource Region N.

116C—St. Francois Knobs and Basins

This area is entirely in southeast Missouri (fig. 116C-1). It

makes up about 1,600 square miles (4,150 square kilometers).

The towns of Farmington, Fredericktown, Ironton, and Park

Hills are the largest municipalities in this area. U.S. Highway 67

crosses this area from north to south. The largest area of public

land in the MLRA is the Mark Twain National Forest. Unique

rock formations are in Elephant Rocks State Park, Johnson’s

Shut-Ins State Park, and the Mudlick Mountain Natural Areas.

Physiography

This area is in the Springfield-Salem Plateaus Section of the

Ozark Plateaus Province of the Interior Highlands. It is the

structural center of the Ozark dome. Three different topographic

expressions are in this MLRA. One is the prominent

Precambrian igneous knobs and hills that rise conspicuously to

various elevations. Another is the intervening smooth-floored

basins and valleys overlying dolostone and sandstone. The

third consists of tracts of deeply dissected, cherty, sedimentary

hills of the Ozarks Highlands that are intermixed with the other

two kinds of topography. The boundary of the area is drawn to

encompass all of the major Precambrian surfaces in the area.

Since the Precambrian surfaces are intermixed with younger

Paleozoic surfaces, a large area of cherty, sedimentary rock

normally found in the adjacent Ozark Highland (MLRA 116A)

is included in this area. Elevation ranges from about 450 feet

(135 meters) along the rivers in the southern part of the area to

1,772 feet (540 meters) on the summit of Taum Sauk Mountain,

the highest point in Missouri. Local relief is generally about

300 to 1,000 feet (90 to 305 meters) among the igneous knobs,

100 to 200 feet (30 to 60 meters) in the basins, and 200 to 300

feet (60 to 90 meters) in the sedimentary hills.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Lower Mississippi-St. Francis (0802), 60 percent; Upper

Mississippi-Kaskaskia-Meramec (0714), 29 percent; and Upper

White (1101), 11 percent. Because it is at the highest elevation

in the Ozark Uplift, this area includes the headwaters of streams

that radiate outward in several directions. The St. Francis River,

which has the largest river basin in this MLRA, drains the

south-central part of the area. The Castor River flows southward

on the eastern boundary of the area. The south-flowing Black

River has its headwaters in the western part of the area. The Big

River, the largest tributary of the Meramec River, drains to the

north.
378 Major Land Resource Areas

Geology

The distinctive geologic features of this area are the

Precambrian igneous rocks that have been uplifted and exposed

by geologic erosion. These exhumed igneous rocks consist

primarily of granites with intruded rhyolites and other

volcanics. The rocks are resistant to erosion and stand out at

high elevations on the landscape. The igneous knobs are broad

and rounded. Slopes in areas of rhyolites are noticeably steeper

than those in areas of granite. The igneous knobs are

interconnected by Early Cambrian sedimentary rocks. The

Cambrian strata consist of the LaMotte sandstone, Derby-Doe

Run dolostone, Bonne Terre dolostone, and Potosi and

Eminence cherty dolostones. The sandstone and the cherty

dolostones are associated with hilly landscapes, whereas the

chert-free dolostones are on the smooth floors of the basins.

This area has valuable mineral deposits, including lead, iron,

manganese, silver, cobalt, and dimension stone (granite). The

area has one of the largest historic lead-mining districts in the

world. Lead mining has left numerous scars on the landscape.

Climate

The average annual precipitation in this area is 40 to 46

inches (1,015 to 1,170 millimeters). The rainfall is fairly evenly

distributed throughout the year. Snow falls nearly every winter,

but the snow cover lasts for only a few days. The annual

snowfall averages about 14 inches (355 millimeters). The

average annual temperature is about 54 to 56 degrees F (12 to

14 degrees C). The lower temperatures occur at the higher

elevations. The freeze-free period averages 200 days and ranges

from 185 to 215 days. The shorter freeze-free periods occur at

the higher elevations.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 10.7%; ground water, 3.9%

Livestock—surface water, 1.1%; ground water, 0.7%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 79.6%; ground water, 4.1%

The total withdrawals average 46 million gallons per day

(175 million liters per day). About 9 percent is from ground

water sources, and 91 percent is from surface water sources. In

most years the precipitation is adequate for crops and pasture,

although summer droughts of sufficient severity and duration to

reduce yields are common. Springs, ponds, and streams provide

water for livestock. Springs are common, although not so large

as elsewhere in the Ozarks. Ponds for livestock water are mainly

in the cleared basins. Stream gradients are generally steep, and

water velocities are high. Stream discharges reach their peak in

spring and decline rapidly in summer. They are lowest in fall.

Several small lakes have been built for residential

developments and water supplies. One unique lake, Taum Sauk

Reservoir, was built for pumped-storage hydroelectricity

generation on the top of Proffit Mountain. Lakes have also

been built to impound and settle out tailings from lead mines.

Most of the surface water used in this area is for the mining

industry. The water is generally of high quality, although in

some areas it is affected by lead mining and pollution from

urbanization. There are no natural lakes and no large reservoirs

in this MLRA.

Ground water is adequate in the areas with sedimentary

bedrock. It is not abundant in the igneous areas. Ground water

sources include the Cambrian sediments and the Ozark

dolomite that occur between the igneous knobs. The water is of

good quality. Limited amounts of the water are used for public

supply, municipal and industrial supply, and domestic

purposes. Data on water quality from this particular area are not

available. The Ozark aquifer has a median level of total

dissolved solids of 322 parts per million (milligrams per liter)

in other parts of Missouri. The water is hard or very hard but is

not high in iron. Because of the karst topography where the

carbonate sediments are at or very near the ground surface,

contaminated water from surface activities has created some

local water-quality problems in this bedrock aquifer. Hazardous

waste, landfills, municipal and industrial wastewater, and

agricultural activities have caused some contamination by

heavy metals, bacteria, and nitrates.

Soils

Most of the soils in this area are Alfisols or Ultisols. They

formed in material weathered from igneous and sedimentary

rocks. The less sloping areas have a thin mantle of loess. The

soils have a mesic soil temperature regime and a udic soil

moisture regime and typically have mixed mineralogy.

Downslope movement by gravitational creep and overland

waterflow has altered the upper part of the soils. In general, the

soils are shallow to very deep, moderately well drained to

excessively drained, and moderately coarse textured to fine

textured.

Many of the soils on igneous knobs are Hapludults (Irondale,

Knobtop, Taumsauk, and Trackler series), Paleudults

(Frenchmill series), or Fragiudults (Delassus and Killarney

series). Many of the soils in basins are Hapludalfs (Bucklick

and Caneyville series) or Paleudalfs (Courtois, Crider, and

Fourche series). Many of the soils on moderately sloping to

steep side slopes in the uplands are Paleudults (Firebaugh and

Clarksville series), Paleudalfs (Alred and Goss series), or

Fragiudults (Captina and Scholten series). Many of the soils on

terraces and the adjacent flood plains are Hapludalfs

(Bearthicket, Secesh, and Tilk series), Udifluvents (Midco and

Relfe series), or Eutrudepts (Gladden and Jamesfin series).
of the United States 379

Biological Resources

Most of this area is in oak or oak-pine forest. White oak,

northern red oak, and hickories are the dominant tree species on

the most productive sites. Post oak, black oak, shortleaf pine,

and hickories dominate the drier sites. Warm-season grasses,

shrubs, and eastern redcedar are dominant in glades. Fescue and

orchardgrass are the dominant introduced grass species.

The major wildlife species are those that prefer woodland

habitat, such as white-tailed deer, gray squirrel, raccoon, and

wild turkey. Small fur animals, such as red fox, gray fox,

opossum, and skunk, are fairly abundant. Wetland habitat is

almost nonexistent, and the waterfowl population is low.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 8%

Grassland—private, 19%; Federal, 1%

Forest—private, 59%; Federal, 6%

Urban development—private, 4%; Federal, 1%

Water—private, 1%

Other—private, 1%

Timber production, outdoor recreation and tourism, and

livestock production are the major land uses in this area. Urban

growth is limited to the U.S. Highway 67 corridor and the

Ironton area. Corn and soybeans are the major cash crops grown

in the area. A few mines are still active in the area.

The major natural resource concerns in this area are forest

and pasture health and productivity, excessive runoff, excessive

nutrients and organic material in the surface water, head-cut

erosion in drainageways in pastured areas, fragmentation of the

wildlife plant community, and inadequate water supplies for

livestock. The important conservation practices are

improvement of forest stands and wildlife habitat, erosioncontrol structures that include hydrants to supplement

livestock water and to control head-cut erosion, prescribed

grazing, development of springs, construction of ponds for

livestock water, pasture and hayland planting, nutrient

management, riparian forest buffers, and exclusion from use as

needed. 

Figure 117-1: Location of MLRA 117 in Land Resource Region N.

117—Boston Mountains

This area (shown in fig. 117-1) is in Arkansas (82 percent)

and Oklahoma (18 percent). It makes up about 6,850 square

miles (17,755 square kilometers). The town of Batesville,

Arkansas, is at the east end of this area, and Fayetteville,

Arkansas, is just outside the northern boundary in the western

part of the area. There are no interstate highways in this area.

The Ozark National Forest makes up a significant portion of the

area.

Physiography

This area is mostly in the Boston “Mountains” Section of

the Ozark Plateaus Province of the Interior Highlands. The

northern half of the western tip of the area is in the SpringfieldSalem Plateaus Section of the same province and division. The

southern half of the western tip is in the Arkansas Valley

Section of the Ouachita Province of the Interior Highlands. This

MLRA marks the southern extent of the Ozarks. It is an old

plateau that has been deeply eroded. Ridgetops are narrow and

rolling. Valley walls are steep. Elevation ranges from 660 feet

(200 meters) on the lowest valley floors to 2,625 feet (800

meters) on the highest ridge crests. Local relief commonly

exceeds 100 feet (30 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Upper White (1101), 53 percent; Lower Arkansas (1111), 45

percent; and Neosho-Verdigris (1107), 2 percent. The Mulberry,

King, Buffalo, and Middle Fork Little Red Rivers are in the part

of this area in Arkansas, and the Illinois River is in the part in

Oklahoma. The Buffalo River is a National River, and Lee

Creek, in the southwest corner of the area, in Arkansas, has been

designated a National Wild and Scenic River.

Geology

Most of this area is underlain by level to slightly tilted

shale, sandstone, and siltstone strata in the Pennsylvanian-age

Atoka Formation and the Cane, Boyd Shale, and Prairie Grove

members of the Hale Formation. Parts of the northern edge are

underlain by the Mississippian-age Pitkin Limestone,

Fayetteville Shale, and Batesville Sandstone. Alluvium

consisting of an unconsolidated mixture of clay, silt, sand, and

gravel is deposited in river valleys.
380 Major Land Resource Areas

Climate

The average annual precipitation in this area is 42 to 55

inches (1,065 to 1,395 millimeters). The maximum

precipitation occurs in spring and fall, and the minimum occurs

in midsummer. Most of the rainfall occurs as high-intensity,

convective thunderstorms. Snowfall is uncommon in winter.

The average annual temperature is 55 to 61 degrees F (13 to 16

degrees C). The freeze-free period averages 225 days and ranges

from 200 to 245 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 24.4%; ground water, 5.1%

Livestock—surface water, 8.1%; ground water, 0.6%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 61.8%; ground water, 0.0%

The total withdrawals average 95 million gallons per day

(360 million liters per day). About 6 percent is from ground

water sources, and 94 percent is from surface water sources. The

moderately high precipitation is adequate for crops and pasture.

Small ponds on individual farms provide water for livestock,

and springs are numerous on the mountainsides and in the

valleys. Large reservoirs on a few of the major streams are

sources of municipal water and provide flood control and

opportunities for recreation. The surface water is generally of

good quality and is suitable for most uses. Municipal and

industrial wastewater discharges and nonpoint pollution have

caused some local degradation of the water quality.

Shallow wells are the principal sources of water for domestic

use. Deep wells are needed to obtain moderate to large

quantities of ground water. Water from the Ozark aquifer system

in the northern half of this area is suitable for drinking. It is

hard or very hard, so treatment to remove calcium and/or

magnesium may be needed. The average concentration of total

dissolved solids is about 270 parts per million (milligrams per

liter). The shallow aquifers within this system have the highest

average level of nitrate of all aquifers in Arkansas. The average

concentration, however, is still less than 1 part per million

(milligram per liter).

Soils

The dominant soil orders in this MLRA are Ultisols and

Inceptisols. The soils in the area dominantly have a thermic soil

temperature regime, a udic soil moisture regime, and mixed or

siliceous mineralogy. They are shallow to very deep, generally

well drained, and loamy. Hapludults (Enders, Linker,

Mountainburg, and Steprock series) and Dystrudepts (Hector

series) formed in residuum on hills, plateaus, and mountains.

Paleudults formed in alluvium or colluvium over residuum

(Allen and Nella series) and alluvium or colluvium (Leesburg

series) on hills and terraces.

Biological Resources

This area supports hardwood forests. The primary overstory

species are red oak, white oak, and hickory. Shortleaf pine and

eastern redcedar are important on disturbed sites, on shallow

soils, and on south or west aspects. Big bluestem, switchgrass,

Indiangrass, and little bluestem are important understory

species under medium to open forest canopy. Broadleaf uniola,

longleaf uniola, wildrye, and low panicums are important

species under heavy canopy.

Some of the major wildlife species in this area are whitetailed deer, coyote, red fox, gray fox, bobcat, beaver, raccoon,

opossum, skunk, muskrat, mink, cottontail, fox squirrel, gray

squirrel, bobwhite quail, and mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 1%

Grassland—private, 22%; Federal, 3%

Forest—private, 48%; Federal, 18%

Urban development—private, 3%

Water—private, 2%; Federal, 2%

Other—private, 1%

About two-thirds of this area is forested. The forested areas

are mainly in farm woodlots, but large tracts in Arkansas are

national forests. About one-fourth of the area is grazing land,

and a small percentage is cropland. Small grains and hay for

livestock are the main crops. Peach and apple orchards are

important locally. Most of the pastures support cultivated

grasses and legumes, but native grasses grow on the prairie

outliers in the western part of the area.

The major resource concerns in this area are gully and

streambank erosion; plant productivity, health, and vigor; soil

contaminants from applications of animal waste; and water for

livestock. Conservation practices on cropland generally

include critical area planting, protection of streambanks and

shorelines, fencing, riparian forest buffers, forage harvest

management, nutrient management, waste utilization, brush

management, pest management, grade-stabilization structures,

construction of ponds, and prescribed grazing. 
of the United States 381

Figure 118A-1: Location of MLRA 118A in Land Resource Region N.

118A—Arkansas Valley and Ridges,

Eastern Part

This area (shown in fig. 118A-1) is in Arkansas (75 percent)

and Oklahoma (25 percent). It makes up about 6,755 square

miles (17,510 square kilometers). The towns of Poteau and

Sallisaw, Oklahoma, and Booneville, Clarksville, Fort Smith,

Greenwood, and Ozark, Arkansas, are in the western part of this

area. The towns of Conway, Morrilton, Russellville, and Searcy,

Arkansas, are in the eastern part. Part of Little Rock, Arkansas,

is in the southeast corner of the area. Interstate 40 passes

through this MLRA from east to west and parallels the northern

side of the Arkansas River. The Ozark National Forest and the

northern fringe of the Ouachita National Forest occur in this

area. Fort Chaffee, Camp Joseph T. Robinson, and Little Rock

Air Force Base are in the area.

Physiography

Most of this area is in the Arkansas Valley Section of the

Ouachita Province of the Interior Highlands. Small areas in the

southeast corner and the south-central part of the MLRA are in

the Ouachita Mountains Section of the same province and

division. This MLRA consists of long, narrow ridges and high

flat-topped mountains capped with sandstone that trend

northeastward. Crests are narrow and rolling on ridges and

broad and flat on mountaintops. The intervening valleys are

broad and smooth. Elevation ranges from 300 feet (90 meters)

on the lowest valley floors to 2,750 feet (840 meters) on the

mountaintops.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Lower Arkansas (1111), 85 percent; Lower Mississippi-St.

Francis (802), 6 percent; Upper White (1101), 5 percent; and

Lower Canadian (1109), 4 percent. The Arkansas River, which

is regulated by numerous locks, dams, and reservoirs, is a major

inland navigational river. It flows from the northwestern part of

the MLRA, at Robert S. Kerr Lake, in Oklahoma, through the

MLRA to the southeastern part of the area, at Little Rock,

Arkansas.

Geology

The ridges and valleys in this area are underlain by slightly

folded to level beds of sandstone and shale, respectively. The

area principally consists of the Savanna group, McAlester

group, Hartshorne sandstone group, and the upper and lower

Atoka group. These are all of Pennsylvanian age. The terrace

deposits along the Arkansas River include a complex sequence

of unconsolidated gravel, sandy gravel, sands, silty sands, silts,

clayey silts, and clays. The individual deposits commonly are

lenticular and discontinuous. At least three terrace levels are

recognized. The lowest is the youngest.

Climate

The average annual precipitation is 41 to 45 inches (1,040

to 1,145 millimeters) in the western one-third of this area. It is

45 to 61 inches (1,145 to 1,550 millimeters) in the eastern twothirds of the area. Most of the rainfall occurs as frontal storms in

spring and early summer. Some high-intensity, convective

thunderstorms occur in summer. Precipitation occurs as rain and

snow in January and February. The average seasonal snowfall is

5 inches (125 millimeters). The average annual temperature is

58 to 62 degrees F (14 to 17 degrees C). The freeze-free period

averages 240 days and ranges from 220 to 260 days. It is

shortest at the higher elevations on ridges.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 8.4%; ground water, 0.9%

Livestock—surface water, 3.5%; ground water, 0.2%

Irrigation—surface water, 26.7%; ground water, 1.0%

Other—surface water, 59.3%; ground water, 0.0%

The total withdrawals average 340 million gallons per day

(1,285 million liters per day). About 2 percent is from ground

water sources, and 98 percent is from surface water sources. The

moderate precipitation generally is adequate for crops and

pasture. In the uplands, water for livestock is obtained from

small ponds on individual farms. In the valleys, springs, small

ponds, and perennial streams provide water for most uses.

Several large reservoirs are used for flood control and for
382 Major Land Resource Areas

118B—Arkansas Valley and Ridges,

Western Part

This area is entirely in Oklahoma (fig. 118B-1). It makes up

about 3,070 square miles (7,960 square kilometers). It has no

major cities. The towns of Henryetta and McAlester are in the

area. Interstate 40 passes through the northern part of the area

from east to west. The McAlester Army Ammunition Plant is in

this area.

Physiography

Most of this area is in the Osage Plains Section of the

Central Lowland Province of the Interior Plains. Parts of the

east side of the area are in the Arkansas Valley and Ouachita

Mountains Sections of the Ouachita Province of the Interior

Highlands. The topography of the area is characterized by long,

narrow sandstone-capped ridges that trend northeastward. The

ridges are dissected by valleys cut by streams at right angles to

the ridges. The valleys and scarp areas generally are cut into

recreation. Surface water for irrigation is obtained primarily

from the Arkansas River. This river is being considered as a

source of public supply water. Naturally occurring saline seeps

impact the salinity of the Arkansas River, and industrial and

municipal waste discharges also cause some degradation in

water quality. One of the major uses of water from the Arkansas

River is for cooling the nuclear power plant at Russellville. The

surface water in the other streams in the area is generally of

good quality and is suitable for most uses.

This area has very little ground water. It has no bedrock

aquifers. Isolated alluvial deposits along the Arkansas River in

both States provide high yields to irrigation wells. Water from

this aquifer has median levels of total dissolved solids of less

than 500 parts per million (milligrams per liter). As a result, it is

suitable as irrigation water. It is very hard, however, and has

high levels of iron. Extensive treatment is needed to make this

water suitable for public supply. Rural landowners in valleys

away from the Arkansas River obtain some water for domestic

use and livestock from shallow wells in alluvium.

Soils

The dominant soil orders in this MLRA are Ultisols. The

soils in the area dominantly have a thermic soil temperature

regime, a udic soil moisture regime, and mixed or siliceous

mineralogy. They are stony or nonstony and are medium

textured. Well drained, shallow and moderately deep

Hapludults (Mountainburg and Linker series) formed on

ridgetops, benches, and the upper slopes. Well drained, deep

Hapludults (Enders series) and Paleudults (Nella series) formed

on the middle and lower slopes and in concave areas between

ledges. Fragiudults (Leadvale, Taft, and Cane series) formed in

valleys. Udifluvents (Roxana series), Udipsamments (Crevasse

series), Haplaquolls (Roellen series), and Hapludalfs (Gallion

series) are minor soils along the Arkansas River, and

Dystrochrepts (Barling series) and Hapludults (Spadra and

Pickwick series) are minor soils on terraces along the smaller

streams.

Biological Resources

The pristine vegetation of this area was oak savanna and

oak-hickory-pine forest. The primary overstory species are red

oak, white oak, and hickory. Shortleaf pine is important on

disturbed sites, on shallow soils, and on south and west aspects.

Big bluestem, switchgrass, Indiangrass, and little bluestem are

important understory species under medium to open forest

canopy. Broadleaf uniola, longleaf uniola, wildrye, and low

panicums are important species under heavy canopy.

Some of the major wildlife species in this area are whitetailed deer, coyote, armadillo, beaver, raccoon, skunk, opossum,

muskrat, cottontail, mourning dove, turkey, fox squirrel, and

gray squirrel.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 6%

Grassland—private, 44%; Federal, 4%

Forest—private, 32%; Federal, 2%

Urban development—private, 6%

Water—private, 4%

Other—private, 2%

Most of this MLRA is pasture, hayland, or forestland. Most

of the privately owned land consists of farm woodlots and

pasture. The poultry business has grown into a major industry

in this area. Most of the cropland in the area is in the less

sloping valleys, but some is on flat mountaintops. Small grains

and hay are the major crops. Soybeans are an important crop on

the bottom land along the Arkansas River. Orchards, vineyards,

and vegetable crops are important locally. Pastures are on the

bottom land along small streams and throughout the cleared

parts of uplands. They support a mixture of tame and native

grasses and legumes.

The major resource concerns are excessive nutrients and

organic material in surface water; forest and pasture

productivity, health, and vigor; and inadequate water sources

for domestic animals. The important conservation practices in

the area are management of phosphorus from chicken litter

applied to cropland and pasture, forest stand improvement,

prescribed grazing, development of springs, riparian forest

buffers, and construction of ponds. 
of the United States 383

Figure 118B-1: Location of MLRA 118B in Land Resource Region N.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 65.9%; ground water, 6.1%

Livestock—surface water, 28.0%; ground water, 0.0%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 0.0%; ground water, 0.0%

The total withdrawals average 26 million gallons per day

(100 million liters per day). About 6 percent is from ground

water sources, and 94 percent is from surface water sources. The

moderate precipitation generally is adequate for crops and

pasture. In the uplands, water for livestock is obtained from

small ponds on individual farms. Springs, small ponds, and

perennial streams provide water for most uses in the valleys.

Several large reservoirs are used for flood control, recreation,

and some drinking water. The surface water is generally of good

quality and is suitable for most uses.

This area has very little ground water. It has no bedrock

aquifers. Isolated alluvial deposits along the Canadian,

Arkansas, and Verdigris Rivers provide some public supply

water. The water in this alluvial aquifer has a median level of

total dissolved solids of 485 parts per million (milligrams per

liter). It is very hard, so treatment is required to make the water

suitable for public supply. Rural landowners away from the

major river valleys obtain small quantities of water for domestic

use from shallow wells in alluvium and fractures in the bedrock.

Soils

Most of the soils in this MLRA are Udalfs or Udepts. They

have a thermic soil temperature regime, a udic soil moisture

regime, and mixed or siliceous mineralogy. Moderately deep,

gently sloping to steep Hapludalfs (Clearview series) formed on

ridgetops, shoulder slopes, and side slopes. Very deep, gently

sloping to sloping Paleudalfs (Stigler series) formed on the side

slopes of valleys. Deep, gently sloping to steep Hapludalfs

(Endsaw series) formed on side slopes and footslopes. Shallow,

sloping to steep Dystrudepts (Clebit and Hector series) formed

on narrow ridgetops and the upper shoulder slopes. Very deep,

gently sloping to steep Paleudalfs (Larton and Porum series)

and Hapludalfs (Karma series) are minor soils on terraces along

streams. Nearly level to sloping Hapludolls (Verdigris series)

and Udifluvents (Severn series) are minor soils along flood

plains throughout the area.

Biological Resources

The pristine vegetation of this area was oak savanna. The

primary trees that make up the overstory are red oak, white oak,

and hickory. Pine grows in some isolated areas, but it is of

minor importance. Big bluestem, switchgrass, Indiangrass, and

little bluestem are important understory species under medium

less resistant shale units. Elevation ranges from 550 feet (170

meters) to 1,500 feet (455 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Lower Canadian (1109), 44 percent; Red-Sulphur (1114), 29

percent; North Canadian (1110), 18 percent; and Lower

Arkansas (1111), 9 percent. The North and South Canadian

Rivers flow from the western part of this area and merge at

Eufaula Lake on the east side of the area. A narrow extension of

this area catches part of the Arkansas and Verdigris Rivers

southeast of Tulsa. The Arkansas River is heavily regulated by

locks, dams, and reservoirs. It allows Mississippi River barge

traffic to reach land-locked Tulsa, which is northwest of this

area.

Geology

This area principally consists of hard and soft sandstone,

shale, siltstone, limestone, and some conglomerates of the

Cabaniss, Krebs, and Marmaton groups. These are all of

Pennsylvanian age. They may include economically viable

coal deposits. The bedrock geology of the area is tilted 2 to 15

degrees from the horizontal and is gently folded in some areas.

Unconsolidated clay, silt, sand, and gravel are deposited in the

river valleys.

Climate

The average annual precipitation in this area is 39 to 46

inches (990 to 1,170 millimeters). Most of the precipitation

falls from April through September. The average annual

temperature is 59 to 62 degrees F (15 to 17 degrees C). The

freeze-free period averages 235 days and ranges from 220 to

255 days. The shorter freeze-free periods occur at the higher

elevations on top of the major ridges.
384 Major Land Resource Areas

Figure 119-1: Location of MLRA 119 in Land Resource Region N.

to open canopy. Broadleaf uniola, longleaf uniola, wildrye, and

low panicums are important species under heavy canopy.

Some of the major wildlife species in this area are whitetailed deer, bobwhite quail, coyote, eastern turkey, fox squirrel,

and gray squirrel.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 3%

Grassland—private, 48%; Federal, 2%

Forest—private, 33%; Federal, 2%

Urban development—private, 6%

Water—private, 5%

Other—private, 1%

About 32 percent of this area is pasture or hayland, and 18

percent is rangeland. Most of the pasture and rangeland is

grazed by beef cattle. The pasture and hayland mainly support

introduced grasses and legumes. Wheat, soybeans, and grain

sorghum are the major crops grown on the small acreage of

cropland in the area. The forested areas are covered with lowgrade mixed hardwoods, and forest products are of very minor

importance. Some areas are used for urban development.

Strip-mining of coal is common throughout the area.

Stabilizing strip-mine spoil and reclaiming mined areas are

major management concerns. Maintaining pasture and forest

productivity also is important.

The important conservation practices in this area are forest

stand improvement, prescribed grazing, development of springs,

riparian forest buffers, and construction of ponds. 

119—Ouachita Mountains

This area (shown in fig. 119-1) is in Arkansas (57 percent)

and Oklahoma (43 percent). It makes up about 11,885 square

miles (30,800 square kilometers). The towns of Mena and

Murfreesboro, Arkansas, and Poteau, Oklahoma, are in this area.

The cities of Benton and Hot Springs, Arkansas, are at the east

end of the area. Little Rock, Arkansas, is just east of the area.

Interstate 30 crosses the southeastern part of the area. Hot

Springs National Park, the Ouachita National Forest, and a

number of State parks are in the part of this MLRA in Arkansas.

Physiography

This area is in the Ouachita Mountains Section of the

Ouachita Province of the Interior Highlands. The steep

mountains are underlain by folded and faulted sedimentary and

metamorphic rocks. Most of the stream valleys are narrow and

have steep gradients, but wide terraces and flood plains border

the Ouachita River in western Arkansas. Elevation ranges from

330 feet (100 meters) on the lowest valley floors to 2,625 feet

(800 meters) on the highest mountain peaks. Local relief is

generally 100 to 200 feet (30 to 60 meters), but it can exceed

980 feet (300 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Red-Sulphur (1114), 38 percent; Lower Arkansas (1111), 29

percent; Lower Red-Ouachita (0804), 29 percent; and Lower

Canadian (1109), 4 percent. The Muddy Boggy, Kiamichi,

Little, Fourche Maline, and Poteau Rivers are in the part of this

MLRA in Oklahoma. The Petit Jean, Fourche LaFaye, Ouachita,

and Caddo Rivers are in the part in Arkansas. The Cossatot,

Little Missouri, and Mountain Fork Rivers, in the southern part

of this area, have been designated as National Wild and Scenic

Rivers.

Geology

These steep mountains are underlain by folded and faulted

formations, dominantly of shale and sandstone. Ordovician-age

shale and sandstone are included in the Collier Shale, Crystal

Mountain Sandstone, and Womble Shale. Mississippian-age

shale, sandstone, novaculite, and chert are included in the

Arkansas Novaculite and the Stanley Shale. Pennsylvanian-age

shale, slate, quartzite, and sandstone are included in the

Jackfork Sandstone, Johns Valley Shale, and upper Atoka

Formations. Alluvial deposits of silt, sand, and gravel are on the

wide terraces and flood plains that border the Ouachita River in

this area.
of the United States 385

Climate

The average annual precipitation in most of this area is 50 to

66 inches (1,270 to 1,675 millimeters). It decreases to 41 to 49

inches (1,040 to 1,245 millimeters) along the western edge of

the area. The precipitation is fairly evenly distributed

throughout the year. The maximum occurs in spring and early

in autumn. Most of the rainfall occurs as high-intensity,

convective thunderstorms. Snowfall is not common in winter.

The average annual temperature is 57 to 63 degrees F (14 to 17

degrees C). The freeze-free period averages 230 days and ranges

from 205 to 255 days. The shorter freeze-free periods occur at

the higher elevations on the major ridges.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 26.5%; ground water, 0.3%

Livestock—surface water, 9.6%; ground water, 0.3%

Irrigation—surface water, 0.6%; ground water, 0.0%

Other—surface water, 62.6%; ground water, 0.0%

The total withdrawals average 155 million gallons per day

(585 million liters per day). About 1 percent is from ground

water sources, and 99 percent is from surface water sources. The

high precipitation, perennial streams, and reservoirs provide

abundant water. Several large reservoirs are used for water

storage, flood control, and recreation. In the valleys, small

ponds and springs are the main sources of water for domestic

use and for livestock. The surface water is typically of very

good quality in this mountainous area. The area has few

municipal or industrial wastewater discharges, and the lack of

major agricultural enterprises has resulted in very little nonpoint

source pollution.

In the valleys, shallow wells in alluvium are the main sources

of water for domestic use and for livestock. None of the bedrock

aquifers in Arkansas or Oklahoma occur in this area. The

quality of the shallow ground water is very similar to the

quality of the water in the streams and rivers. The ground water

is suitable for drinking.

Soils

The dominant soil orders in this MLRA are Ultisols and

Inceptisols. The soils in the area dominantly have a thermic soil

temperature regime, a udic soil moisture regime, and mixed or

siliceous mineralogy. They are shallow to very deep, generally

somewhat excessively drained to somewhat poorly drained, and

loamy. Dystrudepts (Bismarck and Clebit series) and Hapludalfs

(Clearview series) formed in residuum on hills and mountains.

Hapludults formed in colluvium (Zafra series), colluvium over

residuum (Bengal series), and residuum (Carnasaw, Pirum,

Sherless, Sherwood, Stapp, and Townley series) on hills,

mountains, and plateaus. Udifluvents (Ceda series) formed in

alluvium on flood plains.

Biological Resources

This area supports hardwood-pine forests. The primary

overstory species are southern red oak, black oak, white oak,

and hickories. Pine constitutes as much as 40 percent of the

cover. It consists of shortleaf pine in the uplands and loblolly

pine on the lower alluvial soils. Switchgrass, little bluestem,

and Indiangrass are the primary grass species in the understory.

Prairie cordgrass, plumegrass, low panicums, sedges, and

rushes occur in smaller amounts.

Some of the major wildlife species in this area are coyote,

bobcat, beaver, raccoon, otter, skunk, opossum, muskrat, mink,

cottontail, armadillo, gray squirrel, and turkey. The species of

fish in the area include largemouth bass, bluegill, redear

sunfish, channel catfish, spotted bass, white bass, crappie,

flathead catfish, sucker, bullhead, bowfin, and gar.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 1%

Grassland—private, 16%; Federal, 2%

Forest—private, 54%; Federal, 18%

Urban development—private, 3%

Water—private, 3%; Federal, 2%

Other—private, 1%

More than 70 percent of this MLRA is forested. About onefourth of the forested acreage, mainly in Arkansas, is federally

owned. Some of the forestland is in large holdings, but much of

it is in farm woodlots. Timber production, wood-using

industries, and recreation are important throughout the area.

Nearly one-fifth of the MRLA is grazing land. Most of the

pastures support a mixture of tame grasses and legumes, but

some small prairie outliers in the western part of the area

support native grasses. Forage and small grains are the major

crops on the small acreage of cropland in the area.

The major soil resource concerns are gully and streambank

erosion and the erosion caused by road construction; offsite soil

deposition; plant productivity, health, and vigor; and livestock

water.

Conservation practices on cropland generally include critical

area planting, protection of streambanks and shorelines, riparian

forest buffers, fencing, forest site preparation, pruning of trees

and shrubs, forest harvest trails and landings, forest stand

improvement, pest management, prescribed burning, forage

harvest management, construction of ponds, and nutrient

management. 
386 Major Land Resource Areas

Figure 120A-1: Location of MLRA 120A in Land Resource Region N.

120A—Kentucky and Indiana Sandstone

and Shale Hills and Valleys, Southern Part

This area (shown in fig. 120A-1) is primarily in Kentucky

(83 percent) and Illinois (17 percent). A very small part is in

Indiana. The area makes up about 8,905 square miles (23,080

square kilometers). The towns of Henderson, Owensboro, and

Madisonville, Kentucky, and the small communities of

Gibsonia, Pulley’s Mill, Bloomfield, and Vienna, Illinois, are in

this MLRA. Interstates 24 and 57 cross the part of the MLRA in

Illinois. The Western Kentucky and Pennyrile Parkways cross

the part in Kentucky. Mammoth Cave National Park (and World

Heritage Site) is in the part in Kentucky, and the Shawnee

National Forest is in the part in Illinois. A number of State parks

are in the area.

Physiography

This area is in the Highland Rim Section of the Interior Low

Plateaus Province of the Interior Plains. Both large and small

tributaries of the Ohio River dissect the nearly level to very

steep uplands in the area. The major streams and rivers have

well defined valleys with broad flood plains and numerous

stream terraces. The flood plains along the smaller streams are

narrow. The western part of the area is dominated by gently

sloping to steep slopes. The eastern part is dominated by

sloping to very steep slopes with several levels of benches, a

result of alternating beds of soft shale and hard sandstone

bedrock. The steep and very steep slopes have many bedrock

escarpments. Narrow, nearly level to gently sloping ridgetops

are throughout the area. Elevation ranges from 345 feet (105

meters) on the flood plain along the Ohio River to about 950

feet (290 meters) on the highest ridges. Local relief varies

widely within the area. The bluffs along the Ohio River are as

much as 250 feet (75 meters) above the river valley floor.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Green (0511), 50 percent; Lower Ohio (0514), 43 percent;

Upper Mississippi-Kaskaskia-Meramec (0714), 4 percent; and

Cumberland (0513), 3 percent. The Ohio River flows through

this area, forming the boundary between Indiana and Kentucky

and between Illinois and Kentucky. It is a major transportation

artery, and it provides opportunities for recreation in this area.

The Saline River, in Illinois, joins the Ohio in this area. The

Green River and its many tributaries drain the part of this area

in Kentucky. The Green River, in Mammoth Cave National

Park, has been designated a National Wild and Scenic River.

Geology

The geologic materials in this area are of Early and Middle

Pennsylvanian and Late Mississippian age. The rocks consist

mainly of flat-lying, interbedded sandstone, shale, coal, and

siltstone with minor areas of limestone. Bedrock outcrops are

common on the bluffs along the Ohio River and its major

tributaries. There is some coal mining in this area. A layer of

loess, typically less than 3.5 feet (1 meter) thick, covers the less

eroded parts of the landscape, and the only other surficial

geologic materials are stratified Pleistocene-age sediments

along the Ohio River and its tributaries. Unconsolidated

alluvium is deposited in the river valleys.

Climate

The average annual precipitation in most of this area is 45 to

54 inches (1,145 to 1,370 millimeters). About 60 percent of the

precipitation falls during the freeze-free period. Most of the

rainfall occurs as high-intensity, convective thunderstorms in

summer. Snowfall is common in winter. The average annual

temperature is 55 to 58 degrees F (13 to 14 degrees C). The

freeze-free period averages 210 days and ranges from 190 to

230 days. The longer freeze-free periods occur along the Ohio

River.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 3.7%; ground water, 0.8%

Livestock—surface water, 0.7%; ground water, 0.1%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 91.7%; ground water, 3.0%

The total withdrawals average 1,200 million gallons per day

(4,540 million liters per day). About 4 percent is from ground

water sources, and 96 percent is from surface water sources. In

most years the supply of moisture is adequate for crop

production, but in some years yields are reduced by drought.

Surface water is abundant in the area. The Ohio River, the many
of the United States 387

tributary streams of the Ohio River, springs, and farm ponds are

sources of surface water in the area. The water is used for

recreation, public supply, and coal mining and for cooling

thermoelectric power plants in the area. Water for livestock is

commonly stored in small ponds and reservoirs. The surface

water is generally of good quality and is suitable for almost all

uses.

Good-quality ground water is not abundant in all parts of

this area. Water for domestic use, livestock, and coal mining is

available from underlying hard rock aquifers and from more

shallow sand and gravel deposits in the valleys of the Ohio

River and tributary streams.

The Pennsylvanian-Mississippian aquifer underlies almost

all of this area. Low-yield wells are common in this aquifer in

Illinois. The water in Illinois is typically high in total dissolved

solids, very hard, and very high in iron content. The

Pennsylvanian aquifer is in the coal-mining regions of

Kentucky in this area. It has water that is less saline and not so

hard as the water in the aquifer in Illinois and has about onethird the iron content. Ground water from these two aquifers

requires extensive treatment to reduce the hardness and to

prevent iron staining of appliances before the water is used for

domestic or industrial purposes. The Mississippian aquifer in

Kentucky is mostly limestone and has much fresher water. It is

used for public supply in some communities in the area. Water

from the alluvial deposits is similar in quality to that from the

Pennsylvanian aquifer in Kentucky. The median level of total

dissolved solids is just under 500 parts per million (milligrams

per liter), but the water is very hard and the median level of iron

is just under 1,000 parts per billion (micrograms per liter).

Before it can be used for most purposes, it requires treatment to

reduce hardness and prevent iron staining.

Soils

Most of the soils in this MLRA are Udalfs. Most are medium

textured or moderately fine textured, but some on the lower

hillsides and footslopes are fine textured. Most of the soils have

a mesic soil temperature regime, a udic soil moisture regime,

and mixed mineralogy. Some soils along the major rivers have a

thermic soil temperature regime. The soils in the area formed in

loess or in sandstone, shale, siltstone, or limestone residuum.

Fragiudalfs (Hosmer, Loring, and Zanesville series) and

Fraglossudalfs (Sadler and Grenada series), which have a

fragipan, and Hapludalfs (Wellston and Frondorf series) are the

dominant soils on ridgetops and side slopes. Fragiudults (Tilsit

series) and Hapludults (Gilpin and Shelocta series) are in the

northern part of the area. Hapludolls (Huntington series),

Eutrudepts (Nolin, Lindside, and Chagrin series), and

Endoaquepts (Melvin and Newark series) are loamy soils on

flood plains along the major streams. Endoaquepts and

Epiaqualfs (Karnak and McGary series) are clayey soils in

slackwater areas along the major rivers. Dystrudepts (Cuba and

Steff series), Eutrudepts (Haymond and Wilbur series),

Fluvaquents (Wakeland series), and Endoaquepts (Stendal

series) are loamy soils on flood plains of local origin.

Hapludalfs (Wheeling and Elk series) and Fragiudalfs (Otwood

and Lawrence series) are loamy soils on terraces along the

major streams.

Biological Resources

The soils on uplands in this area support native hardwoods.

Oak and hickory are the dominant tree species. Coves and the

cooler slopes support mixed beech, sugar maple, yellow-poplar,

white ash, red oak, and white oak. Eastern redcedar commonly

grows on the shallower soils overlying limestone. Such bottomland hardwoods as cottonwood, cherrybark oak, pin oak,

Shumard oak, sweetgum, and swamp white oak are on flood

plains. Sedge and grass meadows and scattered trees are on

some lowland sites.

Some of the major wildlife species in this area are whitetailed deer, coyote, gray fox, red fox, beaver, raccoon, skunk,

muskrat, opossum, mink, rabbit, fox squirrel, gray squirrel,

Canada goose, bald eagle, turkey vulture, turkey, ruffed grouse,

woodcock, great horned owl, wood duck, pileated woodpecker,

red-bellied woodpecker, and bobwhite quail.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 36%

Grassland—private, 18%

Forest—private, 23%; Federal, 10%

Urban development—private, 2%

Water—private, 4%

Other—private, 7%

Most of this area consists of privately owned farms. The

farms produce both cash-grain crops and livestock. The less

sloping soils are used for dry-farmed corn for grain and for

soybeans. Some small grains, such as winter wheat and grain

sorghum, also are grown in the area. About one-third of the area

is wooded. Surface coal mines make up a small acreage.

The major soil resource concerns are water erosion,

flooding, wetness, a limited available water capacity, and

maintenance of the content of organic matter and productivity

of the soils. Conservation practices on cropland generally

include systems of crop residue management, especially no-till

systems; cover crops; and nutrient management. Woodland

management practices, such as exclusion of grazing and timber

stand improvement, are important in areas used for timber

production. 
388 Major Land Resource Areas

Figure 120B-1: Location of MLRA 120B in Land Resource Region N.

120B—Kentucky and Indiana Sandstone

and Shale Hills and Valleys, Northwestern

Part

This area is entirely in Indiana (fig. 120B-1). It makes up

about 3,040 square miles (7,875 square kilometers). The towns

of Boonville, Jasper, Tell City, English, Shoals, and French Lick

are in this MLRA. Interstate 64 crosses the southern part of the

MLRA and connects Evansville, Indiana, and Louisville,

Kentucky. Numerous public lands are in this area. The Crane

Naval Weapons Support Center, Scales Lake State Forest,

Lincoln State Park, Lincoln Boyhood National Memorial,

Martin County State Forest, Jackson State and Tillery Hill

Recreation Areas, and Hoosier National Forest are in the

MLRA.

Physiography

This area is in the Highland Rim Section of the Interior Low

Plateaus Province of the Interior Plains. Both large and small

tributaries of the Ohio River dissect the nearly level to very

steep uplands in the area. The major streams and rivers have

well defined valleys with broad flood plains and numerous

stream terraces. The flood plains along the smaller streams are

narrow. Local relief varies widely within the area. The western

part of the area is dominated by gently sloping to steep slopes.

The eastern part is dominated by sloping to very steep slopes

with several levels of benches, a result of alternating beds of

soft shale and hard sandstone bedrock. The steep and very steep

slopes have many bedrock escarpments. Narrow, nearly level to

gently sloping ridgetops are throughout the area. Elevation

ranges from 345 feet (105 meters) on the flood plain along the

Ohio River to about 950 feet (290 meters) on the highest ridges.

The bluffs along the Ohio River are as much as 250 feet (75

meters) above the river valley floor.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Wabash (0512), 54 percent, and Lower Ohio (0514), 46 percent.

The Ohio River flows through this area, forming the boundary

between Indiana and Kentucky. The Anderson River empties

into the Ohio River at Troy, Indiana, which is in the southcentral part of the MLRA. The East Fork of the White River

crosses the northern end of the area. A short reach of the Blue

River, a National Wild and Scenic River, is in the southeastern

part of the area. Patoka Lake, in the southern part of the area, is

a major reservoir on the Patoka River.

Geology

The geologic materials in this area are of Early and Middle

Pennsylvanian and Late Mississippian age. The rocks consist

mainly of flat-lying, interbedded sandstone, shale, coal, and

siltstone with minor areas of limestone. Bedrock outcrops are

common on the bluffs along the Ohio River and its major

tributaries. The surficial geologic materials consist mainly of a

layer of loess, typically less than 3.5 feet (1 meter) thick, on the

less eroded parts of the landscape and stratified sediments of

Pleistocene age along the Ohio River and its tributaries.

Unconsolidated alluvium is deposited in the river valleys.

Climate

The average annual precipitation in most of this area is 43 to

48 inches (1,090 to 1,220 millimeters). About 60 percent of the

precipitation falls during the freeze-free period. Most of the

rainfall occurs as high-intensity, convective thunderstorms in

summer. Snowfall is common in winter. The average annual

temperature is 53 to 56 degrees F (11 to 13 degrees C). The

freeze-free period averages 205 days and ranges from 185 to

225 days. The longer freeze-free periods occur along the Ohio

River.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 2.3%; ground water, 2.0%

Livestock—surface water, 2.0%; ground water, 0.8%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 91.6%; ground water, 1.4%

The total withdrawals average 71 million gallons per day

(270 million liters per day). About 4 percent is from ground

water sources, and 96 percent is from surface water sources. In

most years the supply of moisture is adequate for crop

production, but in some years yields are reduced by drought.

Surface water is abundant in this area. The East Fork of the

White River, the Ohio River and its many tributary streams,

springs, and farm ponds are sources of surface water in the area.
of the United States 389

This water is used for recreation, public supply, and coal

mining and for cooling thermoelectric power plants in this area.

Water for livestock is commonly stored in small ponds and

reservoirs. The surface water in this area generally is of good

quality and is suitable for almost all uses.

Good-quality ground water is not abundant in all parts of

this area. Water for domestic use, livestock, and coal mining is

available from underlying hard rock aquifers and from more

shallow sand and gravel deposits in the valleys along the East

Fork of the White River, the Ohio River, and tributary streams.

The primary aquifer underlying almost all of this area consists

of coal-bearing rocks of Pennsylvanian age. The water from this

aquifer typically has about 500 parts per million (milligrams

per liter) total dissolved solids, is very hard, and has a median

level of iron that approaches 1,200 parts per billion

(micrograms per liter). It requires extensive treatment to reduce

the hardness and to prevent iron staining of appliances before

the water is used for domestic or industrial purposes. Water from

the alluvial deposits in the area is similar in quality to that from

the Pennsylvanian aquifer. The median level of total dissolved

solids is just under 500 parts per million (milligrams per liter),

but the water is very hard and the median level of iron is just

under 1,000 parts per billion (micrograms per liter). Before it

can be used for most purposes, the water requires treatment to

reduce hardness and prevent iron staining.

Soils

The dominant soil orders in this MLRA are Alfisols, Ultisols,

and Inceptisols. The soils in the area have a mesic soil

temperature regime, a udic or aquic soil moisture regime, and

dominantly mixed mineralogy. They formed dominantly in less

than 40 inches of loess and in residuum or colluvium derived

from sandstone, shale, and siltstone. The soils range from

moderately deep to very deep and from poorly drained to

somewhat excessively drained and are loamy, silty, or clayey.

Fragiudalfs (Apalona and Zanesville series) and Hapludalfs

(Wellston series) are the dominant soils on ridgetops and the

upper part of side slopes. Hapludults (Adyeville series) and

Dystrudepts (Tipsaw series) are on strongly sloping to very

steep side slopes, and Hapludults (Tulip series) are on strongly

sloping and steep footslopes. Hapludalfs (Deuchars, Ebal, and

Kitterman series) are on moderately sloping to steep structural

benches and scarps. Endoaquepts (Zipp series), Epiaqualfs

(McGary series), and Hapludalfs (Shircliff and Markland series)

formed in lacustrine sediments on nearly level to strongly

sloping lacustrine terraces or lake plains. Hapludults (Millstone

series), Hapludalfs (Elkinsville series), Fragiudalfs (Sciotoville

series), and Epiaqualfs (Hatfield series) are on terraces along

the Ohio River. Hapludolls (Huntington series), Eutrudepts

(McAdoo and Lindside series), and Endoaquepts (Newark

series) are on flood plains along the major streams. Dystrudepts

(Cuba and Steff series), Eutrudepts (Gatchel and Haymond

series), Endoaquepts (Belknap and Stendal series), and

Fluvaquents (Birds and Bonnie series) are on local flood plains.

Udorthents (Bethesda and Fairpoint series) formed in regolith

from surface-mining operations.

Biological Resources

The soils on uplands support native hardwoods. Oak and

hickory are the dominant tree species. Coves and the cooler

slopes support mixed beech, sugar maple, yellow-poplar, white

ash, red oak, and white oak. Eastern redcedar commonly grows

on the shallower soils overlying limestone. Such bottom-land

hardwoods as cottonwood, cherrybark oak, pin oak, Shumard

oak, sweetgum, and swamp white oak are on flood plains.

Sedge and grass meadows and scattered trees are on some

lowland sites.

Some of the major wildlife species in this area are whitetailed deer, coyote, gray fox, red fox, beaver, raccoon, skunk,

muskrat, opossum, mink, rabbit, fox squirrel, gray squirrel,

Canada goose, bald eagle, turkey vulture, turkey, ruffed grouse,

woodcock, great horned owl, wood duck, pileated woodpecker,

red-bellied woodpecker, and bobwhite quail.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 36%

Grassland—private, 18%

Forest—private, 23%; Federal, 10%

Urban development—private, 2%

Water—private, 4%

Other—private, 7%

Most of this area consists of privately owned farms. The

farms produce both cash-grain crops and livestock. The less

sloping soils are used for dry-farmed corn for grain and for

soybeans. Some small grains, such as winter wheat and grain

sorghum, also are grown in the area. About one-third of the area

is wooded. Surface coal mines make up a small acreage.

The major soil resource concerns are water erosion,

flooding, wetness, a limited available water capacity, and

maintenance of the content of organic matter and productivity

of the soils. Conservation practices on cropland generally

include systems of crop residue management, especially no-till

systems; cover crops; and nutrient management. Woodland

management practices, such as exclusion of grazing and timber

stand improvement, are important in areas used for timber

production. 
390 Major Land Resource Areas

Figure 120C-1: Location of MLRA 120C in Land Resource Region N.

120C—Kentucky and Indiana Sandstone

and Shale Hills and Valleys, Northeastern

Part

This area is entirely in Indiana (fig. 120C-1). It makes up

about 1,050 square miles (2,725 square kilometers). The towns

of Freetown, Floyds Knob, and Nashville are in this MLRA.

Interstate 64 crosses the lower part of the MLRA and connects

Evansville, Indiana, and Louisville, Kentucky. Numerous

public lands are in this area. The Yellowwood, Clark, and

Jackson-Washington State Forests, Brown County State Park,

Hardin Ridge Recreation Area, Paynetown State Recreation

Area, part of the Camp Atterbury Maneuver Training Center,

and Hoosier National Forest are in the MLRA.

Physiography

This area is in the Highland Rim Section of the Interior Low

Plateaus Province of the Interior Plains. Both large and small

tributaries of the Ohio River and the East Fork of the White

River dissect the nearly level to very steep uplands in the area.

The major streams and rivers have well defined valleys with

broad flood plains and numerous stream terraces. The flood

plains along the smaller streams are narrow. Summits are narrow

and are nearly level to gently sloping. Elevation ranges from

380 feet (115 meters) on the northernmost flood plain along the

Ohio River to about 1,060 feet (325 meters) on the highest

ridges. Local relief is mainly 10 to 50 feet (3 to 15 meters), but

it is 50 to 100 feet (15 to 30 meters) along drainageways and

streams and the Knobstone Escarpment is as much as 250 feet

(75 meters) above the valley floor of the rivers.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Wabash (0512), 79 percent, and Lower Ohio (0514), 21 percent.

The Ohio River marks the southern boundary of this area and

forms the State line between Indiana and Kentucky. The White

River skirts the northern end of the area. The East Fork of the

White River and the Muscatatuck and Blue Rivers cross the

area. Monroe Lake, on the Salt River, is in the area.

Geology

The geologic materials in this area are of Early and Middle

Pennsylvanian and Late Mississippian age. The rocks consist

mainly of flat-lying, interbedded sandstone, shale, coal, and

siltstone with minor areas of limestone. Bedrock outcrops are

common on the bluffs along the Ohio River and its major

tributaries. The surficial geologic materials consist mainly of a

layer of loess, typically less than 3.5 feet (1 meter) thick, on the

less eroded parts of the landscape and stratified sediments of

Pleistocene age along the Ohio River and its tributaries.

Unconsolidated alluvium is deposited in the river valleys.

Climate

The average annual precipitation in most of this area is 41 to

47 inches (1,040 to 1,195 millimeters). About 60 percent of the

precipitation falls during the freeze-free period. Most of the

rainfall occurs as high-intensity, convective thunderstorms in

summer. Snowfall is common in winter. The average annual

temperature is 52 to 56 degrees F (11 to 14 degrees C). The

freeze-free period averages 205 days and ranges from 190 to

220 days. The longer freeze-free periods occur along the Ohio

River.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 48.7%; ground water, 37.3%

Livestock—surface water, 8.6%; ground water, 5.4%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 0.0%; ground water, 0.0%

The total withdrawals average 3.5 million gallons per day

(13 million liters per day). About 43 percent is from ground

water sources, and 57 percent is from surface water sources. In

most years the supply of moisture is adequate for crop

production, but in some years yields are reduced by drought.

Monroe Lake, rivers and streams, springs, and farm ponds are

sources of surface water in the area. This water is used for

recreation, public supply, domestic use, and livestock. Water for

livestock is commonly stored in small ponds and reservoirs.

The surface water is generally of good quality and is suitable

for almost all uses.

Good-quality ground water is not abundant in all parts of

this area. Water for public supply, domestic use, and livestock is

available from underlying hard rock aquifers and from more

shallow sand and gravel deposits in valleys along the East Fork
of the United States 391

of the White River, the Ohio River, and tributary streams. The

primary aquifer underlying almost all of this area consists of

coal-bearing rocks of Pennsylvanian age. The ground water

typically has about 500 parts per million (milligrams per liter)

total dissolved solids, is very hard, and has a median level of

iron that approaches 1,200 parts per billion (micrograms per

liter). It requires extensive treatment to reduce the hardness and

to prevent iron staining of appliances before the water is used

for domestic or industrial purposes. In areas away from the

rivers, the ground water supply is the only source of water for

rural landowners and communities. Water from the alluvial

deposits is similar in quality to that from the Pennsylvanian

aquifer. The median level of total dissolved solids is just under

500 parts per million (milligrams per liter), but the water is very

hard and the median level of iron is just under 1,000 parts per

billion (micrograms per liter). Before it can be used for most

purposes, the water requires treatment to reduce hardness and

prevent iron staining.

Soils

The dominant soil orders in this MLRA are Alfisols, Ultisols,

and Inceptisols. The soils in the area have a mesic soil

temperature regime, a udic or aquic soil moisture regime, and

dominantly mixed mineralogy. They formed dominantly in

loess and in residuum derived from siltstone and shale. They

range from moderately deep to very deep and from somewhat

poorly drained to well drained and are loamy, silty, or clayey.

Fragiudults (Spickert and Tilsit series) and Hapludults (Wrays

series) are the dominant soils on ridgetops and the upper parts

of hills and knobs. Halpudalfs (Kurtz series), Hapludults

(Gilwood and Gnawbone series), and Dystrudepts (Brownstown

series) are on moderately sloping to very steep side slopes.

Hapludalfs (Coolville, Rarden, Stonehead, and Wellrock series)

are on the gently sloping to moderately steep lower parts of

side slopes. Hapludalfs (Elkinsville series), Fragiudalfs (Pekin

series), and Fragiaqualfs (Bartle series) are on stream terraces.

Dystrudepts (Beanblossom, Cuba, and Steff series) and

Endoaquepts (Stendal series) are on flood plains.

Biological Resources

The soils on uplands support native hardwoods. Oak and

hickory are the dominant tree species. Coves and the cooler

slopes support mixed beech, sugar maple, yellow-poplar, white

ash, red oak, and white oak. Such bottom-land hardwoods as

cottonwood, cherrybark oak, pin oak, Shumard oak, sweetgum,

and swamp white oak are on flood plains. Sedge and grass

meadows and scattered trees are on some lowland sites.

Some of the major wildlife species in this area are whitetailed deer, coyote, gray fox, red fox, beaver, raccoon, skunk,

muskrat, opossum, mink, rabbit, fox squirrel, gray squirrel,

Canada goose, bald eagle, turkey vulture, turkey, ruffed grouse,

woodcock, great horned owl, wood duck, pileated woodpecker,

red-bellied woodpecker, and bobwhite quail.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 29%

Grassland—private, 13%

Forest—private, 35%; Federal, 9%

Urban development—private, 2%

Water—private, 8%

Other—private, 4%

Most of this area consists of privately owned farms. The

farms produce both cash-grain crops and livestock. Specialty

crops, such as tobacco and apple orchards, are grown on a small

acreage in the area. The less sloping soils are used for dryfarmed corn for grain and for soybeans. Some small grains, such

as winter wheat and oats, also are grown in the area. About 13

percent of the area supports introduced and native grasses.

About 44 percent is wooded. Monroe Lake makes up almost 8

percent of the area.

The major soil resource concerns are water erosion,

flooding, wetness, a limited available water capacity, and

maintenance of the content of organic matter and productivity

of the soils. Conservation practices on cropland generally

include systems of crop residue management, especially no-till

systems; cover crops; and nutrient management. Woodland

management practices, such as exclusion of grazing and timber

stand improvement, are important in areas used for timber

production. 

121—Kentucky Bluegrass

This area (shown in fig. 121-1) is in Kentucky (83 percent),

Ohio (11 percent), and Indiana (6 percent). It makes up about

10,680 square miles (27,670 square kilometers). The cities of

Cincinnati, Ohio, and Louisville, Frankfort, and Lexington,

Kentucky, are in this area. Interstates 64 and 74 cross the

southern and northern ends of the area, respectively. Interstates

65, 71, and 75 also are in the area. Many State parks are

throughout the area.

Physiography

This area is primarily in the Lexington Plain Section of the

Interior Low Plateaus Province of the Interior Plains. The parts

of the area in Indiana and Ohio generally are in the Till Plains

Section of the Central Lowland Province of the Interior Plains.

This MLRA is an area of gently rolling terrain with some
392 Major Land Resource Areas

Figure 121-1: Location of MLRA 121 in Land Resource Region N.

isolated hills and ridges. Elevation ranges from about 660 feet

(200 meters) on the flood plain along the Ohio River to about

980 feet (300 meters) on the higher ridges near Lexington.

Local relief is about 160 to 330 feet (50 to 100 meters) on the

highly dissected hills and 80 feet (25 meters) on the

undulating, broad upland plains.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Kentucky-Licking (0510), 52 percent; Lower Ohio (0514), 24

percent; Middle Ohio (0509), 21 percent; and Great Miami

(0508), 3 percent. The Ohio River separates the States of Ohio

and Kentucky in the northern part of this MLRA. The Great

Miami, White Oak, and Ohio Brush Rivers are all tributaries to

the Ohio River. The lower end of the Little Miami National

Wild and Scenic River is just west of Cincinnati. The

Whitewater River, a major tributary to the Great Miami River, is

in southeastern Indiana and southwestern Ohio. The Salt,

Kentucky, and Licking Rivers are tributaries to the Ohio River

in the part of this area in Kentucky.

Geology

Most of this area has an Ordovician-age limestone that has

been brought to the surface in the Jessamine Dome, a high part

of a much larger structure called the Cincinnati Arch. The strata

of limestone have a propensity to form caves and karst

topography. Younger units of thin-bedded shale, siltstone, and

limestone occur at the eastern and western edges of the area.

The area has no coal-bearing units. Pleistocene-age loess

deposits cover most of the bedrock units in this MLRA, and

some glacial lake sediments are at the surface in the northwest

corner of the area. Unconsolidated alluvium is deposited in the

river valleys.

Climate

The average annual precipitation in most of this area is 41 to

45 inches (1,040 to 1,145 millimeters). It is 45 to 52 inches

(1,145 to 1,320 millimeters) along the southern edge of the

area. About one-half of the precipitation falls during the

growing season. Most of the rainfall occurs as high-intensity,

convective thunderstorms. The annual snowfall averages about

14 inches (370 millimeters). The average annual temperature is

51 to 57 degrees F (10 to 14 degrees C). The freeze-free period

averages 210 days and ranges from 185 to 230 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 8.4%; ground water, 0.6%

Livestock—surface water, 0.4%; ground water, 0.0%

Irrigation—surface water, 0.2%; ground water, 0.0%

Other—surface water, 87.8%; ground water, 2.6%

The total withdrawals average 5,040 million gallons per day

(19,075 million liters per day). About 3 percent is from ground

water sources, and 97 percent is from surface water sources.

Water is abundant in most of this area, and it is suitable for all

uses. In most years precipitation is adequate for crops, but in

some years yields are reduced by drought. Large streams and

constructed lakes supply most of the water in urban areas, and

waterlines supply much of the water in nearby rural

communities. Farm ponds are one of the major sources of water

in other rural communities. Water is diverted from the Great

Miami basin to Mill Creek for the city of Cincinnati.

Large quantities of ground water are available in the valleys

along the Ohio River and its major tributaries. The

unconsolidated sand and gravel aquifer beneath the lower Great

Miami River in southwestern Ohio is one of the most heavily

used aquifers in Ohio. Water from these alluvial aquifers is of

good quality but is very hard. The level of total dissolved

solids averages just under the national secondary drinking

water standard of 500 parts per million (milligrams per liter).

The national secondary drinking water standard for iron, 300

parts per billion (micrograms per liter), was exceeded in 50 to

75 percent of all samples. The high levels of iron and

manganese primarily come from runoff from surface mining in

the upper part of the watershed. Almost all of the samples in the

Louisville area exceeded the drinking water standard of 10

parts per million (milligrams per liter) for nitrates. Leaching

from septic tanks appears to be the primary source of this

contamination.

Wells and cisterns are the major sources of water in rural

communities not served by rural water pipelines from

reservoirs. A karst limestone aquifer underlying almost all of
of the United States 393

this area provides domestic and livestock water. This water is

very hard. This aquifer has the highest average levels of nitrates

of all the aquifers in this area, but only 10 percent of all

samples tested as high as 8 parts per million (milligrams per

liter) nitrate.

Soils

The dominant soil orders in this MLRA are Alfisols,

Inceptisols, and Mollisols. The soils in the area dominantly

have a mesic soil temperature regime, a udic soil moisture

regime, and mixed mineralogy. They are shallow to very deep,

generally well drained, and loamy or clayey. Hapludalfs formed

in residuum on hills and ridges (Beasley, Cynthiana, Eden,

Faywood, Lowell, and McAfee series) and in loess over

residuum on hills and ridges (Carmel and Shelbyville series).

Paleudalfs (Crider and Maury series) formed in loess or other

silty sediments over residuum on hills and ridges. Fragiudalfs

(Nicholson series) formed in loess over residuum on ridges.

Hapludolls formed in residuum on hills and ridges (Fairmount

series) and in alluvium on flood plains (Huntington series).

Eutrudepts (Nolin series) formed in alluvium on flood plains.

Biological Resources

This area generally supports mixed hardwoods. Chinkapin

oak, bur oak, blue ash, Shumard oak, white ash, hackberry,

American elm, black walnut, black cherry, black locust, and

Kentucky coffeetree are important species. Eastern redcedar is

dominant on the drier slopes and on abandoned farmland.

Some of the major wildlife species in this area are whitetailed deer, raccoon, muskrat, mink, cottontail, gray squirrel,

fox squirrel, bobwhite quail, and mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 22%

Grassland—private, 32%

Forest—private, 28%

Urban development—private, 14%

Water—private, 2%

Other—private, 2%

Most of this area consists of small and medium-size farms.

Urbanization is of major extent near Louisville, Lexington, and

Cincinnati. Nearly one-fourth of the area is cropland. The

acreage of cropland varies widely from county to county,

depending largely on the topography. Corn, hay, and tobacco

are the major crops. About one-third of the area is pasture,

which is grazed mostly by beef cattle. Dairying and horse farms

are important in some areas. About one-fourth of the area

supports mixed hardwoods, but wood products are not

commercially important.

The major resource concerns are water erosion, runoff,

sedimentation, and water quality, particularly in areas of urban

development. Air quality also is a concern near the urban areas.

Conservation practices on cropland generally include

conservation tillage, nutrient management, pest management,

grassed waterways, field borders, and grass buffers. 

Figure 122-1: Location of MLRA 122 in Land Resource Region N.

122—Highland Rim and Pennyroyal

This area (shown in fig. 122-1) is in Tennessee (47 percent),

Kentucky (43 percent), Indiana (7 percent), and Alabama (3

percent). It makes up about 21,530 square miles (55,790 square

kilometers). Bloomington, Indiana, is in the small part of this

area that juts into southern Indiana. The towns of Bowling

Green, Fort Knox, and Hopkinsville, Kentucky, Clarksville,

Tennessee, and Athens, Alabama, are in this MLRA. Interstates

24, 40, and 65 cross this area. The historic Natchez Trace

(Natchez Trace Parkway) crosses the southeast part of the area.

Fort Knox and Fort Campbell Military Reservations are in this

MLRA. The Arnold Engineering Development Center, which is

a National Natural Landmark, and the Land Between the Lakes,

which is a Biosphere Reserve, are in the part of this area in

Kentucky. The Biosphere Reserve lies between Kentucky Lake

and Lake Barkley, formed on the Tennessee and Cumberland

Rivers by dams in Kentucky.

Physiography

This area is in the Highland Rim Section of the Interior Low

Plateaus Province of the Interior Plains. It is a plateau

consisting of low, rolling hills, upland flats, and narrow valleys.

Steep slopes occur where the encircled Nashville Basin cuts
394 Major Land Resource Areas

into the area and along the western edge bordering the Coastal

Plain. Elsewhere, except for steep walls and hillsides along

deeply cut stream channels, the topography generally is gently

rolling to strongly rolling and is interrupted in a few areas by

broad upland flats and shallow basins. In many areas the land

surface is pitted by limestone sinks. Elevation generally is 660

to 980 feet (200 to 300 meters). It ranges from about 330 feet

(100 meters) along the deepest valley floors to about 1,310 feet

(400 meters) on the crest of isolated hills.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Cumberland (0513), 39 percent; Green (0511), 22 percent;

Lower Tennessee (0604), 16 percent; Middle Tennessee-Elk

(0603), 11 percent; Lower Ohio (0514), 9 percent; and Wabash

(0512), 3 percent. The headwaters of the Kentucky, Green, and

Cumberland Rivers occur in the part of this area in Kentucky.

The Ohio River forms the boundary between Indiana and

Kentucky in this MLRA. The Tennessee River follows the

western edge of the part of this area in Tennessee. The

Cumberland River also is in this area. The Buffalo River, in

Tennessee, has been designated a National Wild and Scenic

River.

Geology

Most of this area is underlain by Ordovician- to

Mississippian-age limestone and dolomite that has been

exposed through erosion of the Cincinnati Arch. Parts of these

rocks are covered by a layer of clay as much as 80 feet thick.

Karst areas are common where the layer of clay does not occur.

In the northernmost part of the MLRA, in Indiana, a sizable

area is underlain by shale, sandstone, and limestone. Much of

the bedrock on uplands and ridges is covered by a loess cap.

Significant sand and gravel deposits occur on the valley floor

and on terraces along the major rivers.

Climate

The average annual precipitation in this area is 43 to 63

inches (1,090 to 1,600 millimeters), increasing to the south.

The maximum precipitation occurs in winter and early in

spring, and the minimum occurs in fall. Most of the rainfall

occurs as high-intensity, convective thunderstorms. Snowfall

may occur in winter. The average annual temperature is 52 to

60 degrees F (11 to 16 degrees C), increasing to the south. The

freeze-free period averages 210 days and ranges from 185 to

235 days. The longer freeze-free periods occur in the more

southerly parts of the area.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 4.0%; ground water, 1.6%

Livestock—surface water, 0.2%; ground water, 0.2%

Irrigation—surface water, 0.2%; ground water, 0.2%

Other—surface water, 90.2%; ground water, 3.4%

The total withdrawals average 2,055 million gallons per day

(7,780 million liters per day). About 5 percent is from ground

water sources, and 95 percent is from surface water sources. In

most years precipitation is adequate for crops, but in some years

yields are reduced by short dry periods early in summer. The

numerous perennial streams and lakes supply abundant water to

much of the area. The surface water generally is suitable for all

uses. Several medium to large lakes constructed by the U.S.

Army Corps of Engineers provide flood control, power

production, opportunities for recreation, and water for

municipalities. Water lines from metropolitan areas commonly

extend far into the countryside in areas where surface water is

scarce. Farm ponds provide supplemental water in areas where

the supply of other surface water is low.

Most of the ground water used in this area is from a

Mississippian-age carbonate aquifer system. The water occurs

in solution openings and fractures in the limestone and

dolomite. It is very hard but is otherwise of excellent quality.

The median level of total dissolved solids is about 175 parts per

million (milligrams per liter) in Tennessee and about 250 in

Kentucky. In some areas high levels of iron, manganese, and

sulfate can occur. In Indiana and other areas where the levels of

iron are high, they may exceed the national secondary standard

for drinking water, which is 300 parts per billion (micrograms

per liter). The secondary standard is primarily esthetic,

although the iron can stain ceramic and porcelain and

precipitate in pipes. In karst areas this aquifer is susceptible to

contamination from nonpoint sources of pollution in runoff.

Soils

The dominant soil orders in this MLRA are Alfisols,

Inceptisols, and Ultisols. The soils in the area dominantly have

a mesic soil temperature regime, a udic soil moisture regime,

and mixed or siliceous mineralogy. They are moderately deep

to very deep, generally moderately well drained or well drained,

and loamy or clayey. Paleudalfs formed in residuum (Baxter

and Vertrees series) and loess over residuum or old alluvium

(Crider, Hammack, and Pembroke series) on hills and ridges.

Hapludalfs (Caneyville series) and Hapludults (Frankstown

series) formed in residuum on hills and ridges. Fragiudalfs

(Bedford and Nicholson series) and Fragiudults (Dickson

series) formed in loess over residuum on hills and ridges.

Eutrudepts formed in residuum on hills (Garmon series) and in

alluvium on flood plains (Nolin series). Paleudults formed in

residuum on uplands (Frederick series) and in loess over

residuum on ridges and plateaus (Mountview series).

Fluvaquents (Newark series) formed in alluvium on flood

plains.
of the United States 395

Biological Resources

This area supports oak-hickory forests. Yellow-poplar is

common on the deeper soils. Understory plants include a

variety of grasses, forbs, vines, and shrubs. Little bluestem and

broomsedge are the dominant grass species.

Some of the major wildlife species in this area are red fox,

gray fox, raccoon, skunk, opossum, muskrat, mink, cottontail,

gray squirrel, fox squirrel, bobwhite quail, and mourning dove.

The species of fish in the area include carp, bullhead,

largemouth bass, and bluegill.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 23%

Grassland—private, 23%; Federal, 1%

Forest—private, 40%; Federal, 2%

Urban development—private, 6%

Water—private, 3%

Other—private, 2%

Most of this area consists of small and medium-size farms.

Extensive forests are on the deeply dissected hills surrounding

the Nashville Basin and along the western edge joining the

Coastal Plain. Elsewhere, the forests consist mostly of small

farm woodlots. Hay and pasture for beef cattle are the principal

crops. Corn and soybeans, grown mostly on narrow strips of

bottom land and on upland flats, are important locally.

Tobacco, especially burley, is an important cash crop. Darkfired tobacco is a high-value crop grown on the TennesseeKentucky line. Some areas are used for urban development.

The major soil resource concern is water erosion. Erosion is a

hazard on cropland, streambanks, and construction sites. Minor

erosion can occur on overgrazed pastures, and extreme

overgrazing can result in gullies in areas of concentrated flow

and heavy use. Maintenance of the content of organic matter

and productivity of the soils and management of soil moisture

are additional resource concerns in areas where long-term

erosion has occurred.

Conservation practices on cropland generally include

systems of crop residue management, especially no-till systems;

cover crops; pest management; and nutrient management.

Conservation practices on pasture generally include prescribed

grazing, watering systems, protection of heavily used areas,

nutrient management, and pest management. Conservation

practices on hayland generally include forage harvest

management, nutrient management, and pest management.

Critical area planting helps to prevent gully erosion in all

areas. 

Figure 123-1: Location of MLRA 123 in Land Resource Region N.

123—Nashville Basin

This area is entirely in Tennessee (fig. 123-1). It makes up

about 5,625 square miles (14,580 square kilometers). The cities

of Nashville, Franklin, Hendersonville, Columbia,

Murfreesboro, and Shelbyville are in this area. Interstates 24,

40, and 65 intersect in Nashville. The Cedars of Lebanon State

Park and Forest are in the center of this area.

Physiography

Most of this area is in the Nashville Basin Section of the

Interior Low Plateaus Province of the Interior Plains. A small

part of the northeast corner and the western and southern fourth

of the area are in the Highland Rim Section of the same

province and division. Most of the outer part of the Nashville

Basin is deeply dissected and consists of steep slopes between

narrow, rolling ridgetops and narrow valleys. The inner part of

the basin is dominantly undulating and rolling. In many areas

the land surface is deeply pitted by limestone sinks, and

outcrops of limestone are almost everywhere. Elevation

generally is about 650 feet (200 meters), but it is 1,000 to 1,325

feet (305 to 405 meters) on isolated hills and is as low as 450

feet (135 meters) in some of the more deeply cut stream

channels.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Cumberland (0513), 56 percent; Lower Tennessee (0604), 25

percent; and Middle Tennessee-Elk (0603), 19 percent. The

Cumberland River is in the northern part of this area. Two major

tributaries of this river, the Harpeth and Stones Rivers, are in
396 Major Land Resource Areas

this MLRA. A portion of the Harpeth River in the middle of the

western part of this area has been designated a National Wild

and Scenic River.

Geology

The bedrock geology in this area consists of Ordovician

limestone exposed by geologic erosion of the top of the

Nashville Dome (a high part of the Cincinnati Arch) throughout

this area. Sinkholes are common in the limestone and are either

open to the subsurface or are covered by soils and colluvium

that have collected in the depressions formed on the land

surface above the sinkhole. Younger rocks occur as a rim just

outside this area. Surficial deposits include loess on the less

eroded landforms and alluvium along the rivers and streams.

Climate

The average annual precipitation in this area is 48 to 57

inches (1,220 to 1,450 millimeters). The maximum

precipitation occurs in midwinter and early in spring, and the

minimum occurs in autumn. Rainfall primarily occurs during

high-intensity, convective thunderstorms. Some snow occurs in

winter, but it does not remain on the ground for long periods.

The average annual temperature is 56 to 60 degrees F (14 to 16

degrees C). The freeze-free period averages 210 days and ranges

from 195 to 230 days. The longer freeze-free periods occur in

the southern part of the area.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 8.6%; ground water, 0.3%

Livestock—surface water, 0.1%; ground water, 0.3%

Irrigation—surface water, 0.1%; ground water, 0.1%

Other—surface water, 89.0%; ground water, 1.4%

The total withdrawals average 2,660 million gallons per day

(10,070 million liters per day). About 2 percent is from ground

water sources, and 98 percent is from surface water sources. The

moderately high precipitation generally provides adequate

moisture for crops and pasture, but short periods of drought in

summer reduce pasture and crop yields in some years.

Permanent streams and lakes are important sources of water. The

Cumberland River has dams for flood control, power

production, navigation, and recreation. Farm ponds provide

supplemental water, especially in areas where surface water is

scarce because of limestone sinks.

Ground water from wells and springs is an important source

of water for domestic use and for livestock. The water is in the

Ordovician carbonate aquifer that underlies this area. It is hard

and typically has a median level of total dissolved solids of less

than 500 parts per million (milligrams per liter). The water is in

solution openings in this aquifer and is susceptible to

contamination from surface activities in karst areas. For

example, septic systems have contaminated the shallow water in

the part of this aquifer in the Nashville area.

Soils

Many of the soils in this MLRA are Udalfs. The moderately

deep to very deep, well drained, clayey soils formed in

limestone residuum. They are dominantly in rolling to steep

areas of the “Outer Basin” (Mimosa, Braxton, Gladdice, and

Hampshire series) and the undulating to hilly areas of the

“Inner Basin” (Talbott and Bradyville series). The most

agriculturally productive soils are the very deep, well drained,

clayey or loamy soils that formed in alluvium and/or loess over

alluvium or limestone residuum in nearly level to undulating

areas (Armour, Cumberland, Harpeth, Lomond, and Maury

series). The less extensive soils generally are moderately well

drained to somewhat poorly drained and formed in loamy or

clayey alluvium and/or residuum (Byler, Capshaw, Colbert, and

Tupelo series). This MLRA has a significant acreage of

Mollisols. Shallow or moderately deep, well drained, clayey

Udolls (Ashwood and Barfield series) formed in limestone

residuum dominantly in rolling to steep areas. Very shallow,

well drained, clayey Rendolls (Gladeville series) formed in

limestone residuum dominantly in undulating to rolling areas

of the “Inner Basin.” Very deep, well drained or moderately well

drained Udolls (Arrington, Egam, Lynnville, and Staser series)

and somewhat poorly drained or poorly drained Aquolls (Agee,

Godwin, and Lanton series) formed in loamy or clayey

alluvium derived from limestone on flood plains. Most of the

remaining soils on flood plains are moderately well drained or

well drained Udepts (Lindell and Ocana series). Udults are of

small extent in this area. Most are very deep, well drained, and

loamy and formed in gravelly colluvium or colluvium and the

underlying residuum on steep hillsides (Dellrose soils). Rock

outcrops are common on uplands.

Biological Resources

This area supports stands of oak and hickory. Yellow-poplar

grows on the north aspects, and eastern redcedar and cedarhardwood stands grow in limestone glades and on rocky, clayey

sites. The understory vegetation includes many grasses, forbs,

vines, and shrubs. Broomsedge bluestem is the dominant grass

species.

Some of the major wildlife species in this area are whitetailed deer, gray fox, red fox, raccoon, muskrat, cottontail,

mink, gray squirrel, bobwhite quail, and mourning dove. The

species of fish in the area include bass, crappie, and walleye.
of the United States 397

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 14%

Grassland—private, 31%

Forest—private, 36%; Federal, 1%

Urban development—private, 13%

Water—private, 3%

Other—private, 2%

This densely populated area consists mostly of small and

medium-size farms. Much of the farmland has been converted to

residential use and to small estate-type farms, particularly

around Nashville. Hay, pasture, and some grain for beef cattle

and dairy cattle are the principal crops. Small acreages are used

for burley tobacco, cotton, or soybeans. Some large rocky sites,

commonly called “Glady Land,” support redcedar forest or

redcedar-deciduous brush.

The major soil resource concerns in this area are water

erosion, deposition of sediment, depletion of organic matter in

the soils, surface compaction, and soil contaminants.

Conservation practices on cropland generally include systems

of crop residue management, especially no-till systems; cover

crops; and nutrient management. The important conservation

practice on pasture is prescribed grazing. 

Figure 124-1: Location of MLRA 124 in Land Resource Region N.

124—Western Allegheny Plateau

This area (shown in fig. 124-1) is in Ohio (53 percent),

Kentucky (25 percent), and Pennsylvania (22 percent). It makes

up about 12,880 square miles (33,375 square kilometers). It

includes the towns of Punxsutawney, Kittanning, Butler, and

Beaver Falls, Pennsylvania; Dover, Coshocton, Cambridge,

Zanesville, Portsmouth, and Ironton, Ohio; and Ashland and

Morehead, Kentucky. Interstates 64, 70, 76, 79, and 80 cross

this area. The Wayne National Forest covers a significant part of

the area in southern Ohio, and the Daniel Boone National

Forest is in the part in Kentucky. A number of State forests are

in the part in southern Ohio. State parks occur throughout the

area.

Physiography

This area is primarily in the Kanawha Section of the

Appalachian Plateaus Province of the Appalachian Highlands.

The southern edge is in the Cumberland Plateau Section of the

same province and division. The southwestern edge is in the

Lexington Plain Section of the Interior Low Plateaus Province

of the Interior Plains. This MLRA is on a dissected plateau that

has narrow, level valley floors, rolling ridgetops, and hilly to

steep ridge slopes. Elevation ranges from 660 feet (200 meters)

on the lowest valley floors to 1,310 feet (400 meters) on the

highest ridgetops. Local relief is about 160 to 330 feet (50 to

100 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Muskingum (0504), 24 percent; Middle Ohio (0509), 22

percent; Allegheny (0501), 15 percent; Upper Ohio (0503), 14

percent; Kentucky-Licking (0510), 11 percent; Scioto (0506),

11 percent; and Big Sandy-Guyandotte (0507), 3 percent. The

Allegheny River crosses the part of this area in Pennsylvania.

The Muskingum, Raccoon, and Scioto Rivers are in the part in

Ohio. The West Fork Little Beaver River is a National Wild and

Scenic River in Ohio. It is just across the border from

Pennsylvania. The Ohio River forms the boundary between

Ohio and Kentucky in the southern part of this area.

Geology

Cyclic beds of sandstone, siltstone, clay, shale, and coal of

Pennsylvanian age form the bedrock in this area. Similar rocks

of Mississippian age occur along the southwest edge of the area

in Kentucky and southern Ohio. This MLRA is on the east side

of the Cincinnati Arch, so the bedrock is tilted to the east in

Kentucky and Ohio. Old glacial drift deposits are in some of the

major river valleys. Wisconsin-age glacial outwash deposits of

unconsolidated sand and gravel are near the surface in river

valleys in Pennsylvania and Ohio. Wisconsin-age glacial drift

covers the surface in areas to the east and north of this MLRA.

Climate

The average annual precipitation in most of this area is 37 to

45 inches (940 to 1,145 millimeters). It is 45 to 50 inches

(1,145 to 1,270 millimeters) at the southern tip of the area. The

precipitation generally is evenly distributed throughout the year,

except for a slight maximum late in spring and a minimum late
398 Major Land Resource Areas

in autumn. Rainfall occurs as high-intensity, convective

thunderstorms in summer. Winter precipitation occurs as snow.

The average annual temperature is 46 to 56 degrees F (8 to 13

degrees C). The freeze-free period averages 185 days and ranges

from 155 to 220 days. It is longest along the southern edge of

the area.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 7.4%; ground water, 7.2%

Livestock—surface water, 0.5%; ground water, 0.5%

Irrigation—surface water, 0.1%; ground water, 0.0%

Other—surface water, 75.5%; ground water, 8.7%

The total withdrawals average 915 million gallons per day

(3,465 million liters per day). About 16 percent is from ground

water sources, and 84 percent is from surface water sources. The

moderate precipitation and many perennial streams supply an

abundance of surface water. Springs are among the principal

sources of water for domestic use and livestock. Reservoirs on

many streams provide water for industrial and municipal uses in

most of the cities in this area and also in some cities in

adjoining areas. The surface water is suitable for almost all uses

with minimal treatment. Municipal and industrial wastewater

discharges, nonpoint pollution from agricultural lands,

sedimentation from surface mining of coal, and some acid mine

drainage are the primary water-quality problems in this area.

Shallow wells are another major source of water for domestic

use and livestock in this area. These wells are in the sandstone,

shale, and coalbeds or in unconsolidated silt, sand, and gravel

deposits along rivers and streams throughout the area. Their

water is dominantly moderately hard and, except for high levels

of iron, generally meets the national standards for drinking

water. Water from fractures in sandstone generally is soft, and

water from fractures in the shale generally is hard. The highest

iron concentrations are in water from the coal-bearing units.

Deep oil and gas exploration wells tap abundant ground water,

but this water is briny. For example, water from wells in the

Sandstone aquifer in Ohio has a median level of 322 parts per

million (milligrams per liter) total dissolved solids, but the

water is salty below a depth of 300 feet (90 meters).

Contamination from septic systems located too close to

domestic wells is one of the most common water-quality

problems in this area.

Good-quality ground water can be obtained from the glacial

outwash and recent alluvium deposited in the larger stream

valleys throughout this area. High-yield wells are common in

this aquifer, and many municipalities, industries, and

thermoelectric power plants tap this aquifer. The water

generally is very hard but typically meets national drinking

water standards. In some areas it has high levels of iron that

exceed the secondary drinking water standard. Water from most

wells tapping the alluvial deposits in the valley of the Ohio

River in the southern part of this area exceeds the national

secondary standard for total dissolved solids of 500 parts per

million (milligrams per liter).

Soils

The dominant soil orders in this MLRA are Ultisols and

Inceptisols. The soils in the area have a mesic soil temperature

regime, a udic soil moisture regime, and mixed mineralogy.

They generally are moderately deep to very deep, excessively

drained to somewhat poorly drained, and loamy. Fragiudults

and Hapludults (Ernest and Shelocta series) formed in

colluvium on footslopes and alluvial fans. Hapludults (Gilpin,

Latham, Rayne, and Wharton series) and Dystrudepts (Berks,

Steinsburg, and Weikert series) formed in residuum on hills and

ridges. Dystrudepts (Pope series), Endoaquepts (Stendal series),

Eutrudepts (Chagrin series), and Hapludalfs (Chavies series)

formed in alluvium along the major streams. Udorthents

(Bethesda, Sewell, Fairpoint, and Kaymine series) formed in

material derived from surface mining of coal.

Biological Resources

This area supports mixed oak forest vegetation. White oak,

black oak, northern red oak, and some scarlet oak are the

dominant tree species. Shagbark hickory, bitternut hickory,

pignut hickory, and mockernut hickory also occur. Oak,

blackgum, flowering dogwood, sassafras, Virginia pine, pitch

pine, and shortleaf pine grow mostly on ridgetops.

Some of the major wildlife species in this area are whitetailed deer, fox, beaver, raccoon, woodchuck, rabbit, squirrel,

red-tailed hawk, crow, turkey, pheasant, ruffed grouse, pileated

woodpecker, and mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 13%; Federal, 1%

Grassland—private, 13%; Federal, 1%

Forest—private, 60%; Federal, 3%

Urban development—private, 6%

Water—private, 1%

Other—private, 2%

Most of this area consists of farms, but about one-fourth of

the acreage is used for other purposes. Hay and feed grains for

livestock are the principal crops grown in the area, and fruits

and vegetables are important locally. Less than one-fifth of the

area is pasture. Nearly two-thirds of the area is forested. About

half of the forested areas consist of farm woodlots, and about

half consist of State and national forests and large commercial

holdings. Surface mining of coal is an important industry in the

northern part of the area and, to a lesser extent, in the southern
of the United States 399

part, but only a small part of the MLRA has been surface

mined.

The major soil resource concerns are sheet and rill erosion

on pasture, land slippage, subsidence resulting from mining,

streambank erosion, gullying, surface compaction caused by

livestock trampling, and a reduced content of organic matter on

cropland.

Conservation practices on cropland generally include crop

rotations, contour farming, nutrient management, grassed and

forested riparian buffers, cover crops, hayland planting,

diversions, and grassed waterways. Pasture management

includes rotational grazing, watering systems, fencing, managed

livestock access to streams, pasture planting, and nutrient

management. Forest management includes properly constructed

forest harvest trails, critical area planting, and water bars on

trails. 

Figure 125-1: Location of MLRA 125 in Land Resource Region N.

125—Cumberland Plateau and

Mountains

This area (shown in fig. 125-1) is in Kentucky (43 percent),

Tennessee (25 percent), West Virginia (20 percent), Virginia

(9 percent), and Alabama (3 percent). It makes up about 20,330

square miles (52,685 square kilometers). The towns of Logan,

Madison, Welch, and Williamson, West Virginia, and Norton and

Wise, Virginia, are in the northeastern part of this area. The towns

of Middlesboro, Williamsburg, Corbin, London, Hazard, and

Pikeville, Kentucky, and La Follette and Crossville, Tennessee,

are in the area. Chattanooga, Tennessee, and Huntsville, Alabama,

are just outside the southeast and southwest corners, respectively.

Interstates 24, 64/77, 75, and 40/75 cross this area. The

Cumberland Gap National Historic Park is in the part of this area

along the Virginia and Kentucky border. The Daniel Boone and

Jefferson National Forests occur in this area. Numerous State

forests and parks are throughout the area.

Physiography

The northern third of this area is primarily in the Kanawha

Section of the Appalachian Plateaus Province of the

Appalachian Highlands. The southern two-thirds is primarily in

the Cumberland Plateau Section of the same province and

division. A strip along the central part of the east edge of the

area is in the Cumberland Mountain Section of the same

province and division, and small areas of the MLRA along the

southwestern edge are in the Highland Rim Section of the

Interior Low Plateaus Province of the Interior Plains. This

highly dissected MLRA occurs mainly as a series of long, steep

side slopes between narrow ridgetops or crests and narrow

stream flood plains. Elevation ranges from 650 feet (200

meters) on the flood plain along the Ohio River to about 980

feet (300 meters) on nearby ridgetops. It gradually rises from

these areas to areas near the Virginia-Kentucky border, where it

is about 1,650 feet (505 meters) on local flood plains and 3,950

feet (1,205 meters) on the higher mountains.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Cumberland (0513), 30 percent; Big Sandy-Guyandotte (507),

24 percent; Kentucky-Licking (0510), 19 percent; Upper

Tennessee (0601), 10 percent; Kanawha (0505), 8 percent;

Middle Tennessee-Elk (0603), 5 percent; Middle TennesseeHiwassee (0602), 3 percent; and Middle Ohio (0509), 1 percent.

The Kanawha River is the largest river in the part of this area in

West Virginia. The Tug Fork and Big Sandy Rivers form the

State boundary between West Virginia and Kentucky. The

Clinch River forms the southwestern boundary of the part of

this area in Virginia. The headwaters of the Licking, Kentucky,

and Cumberland Rivers are in the part in Kentucky. The New,

Obey, Obed, Caney Fork, and Collins Rivers are in the part in

Tennessee. The Tennessee River is in the part in Alabama. A

number of National Wild and Scenic Rivers are in the parts of

this area in Kentucky and Tennessee.

Geology

Cyclic beds of sandstone, siltstone, clay, shale, and coal of

Pennsylvanian age form the bedrock in most of this area.

Pennsylvanian limestone and dolomite bedrock is in the part of

the area in Virginia and Alabama. Coal mining is the major

industry in this MLRA. Unconsolidated deposits of silt, sand,

and gravel are in the major river valleys and on terraces along

these rivers. The lower parts of many hillslopes have a thin

layer of colluvium.

Climate

The average annual precipitation is mostly 37 to 45 inches

(940 to 1,145 millimeters) in the northern third of this area and
400 Major Land Resource Areas

45 to 60 inches (1,145 to 1,525 millimeters) in the southern

two-thirds. It is almost 60 inches (1,525 millimeters) at the

higher elevations in the northern third of the area and is as

much as 75 inches (1,905 millimeters) in the mountains in the

southern two-thirds. Almost half of the annual precipitation

falls during the growing season. Rainfall typically occurs

during high-intensity, convective thunderstorms in summer.

Snow may occur during winter in the northern part of the area

and at the higher elevations. The average annual temperature is

50 to 60 degrees F (10 to 15 degrees C). The freeze-free period

averages 200 days and ranges from 170 to 225 days. The

shorter freeze-free periods are at the higher elevations and in

the more northerly parts of the area.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 3.7%; ground water, 0.9%

Livestock—surface water, 0.3%; ground water, 0.3%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 85.2%; ground water, 9.6%

The total withdrawals average 1,685 million gallons per day

(6,375 million liters per day). About 11 percent is from ground

water sources, and 89 percent is from surface water sources.

Water is abundant in most of the area. In most years

precipitation is adequate for crops, but in some years yields are

reduced by drought. The large streams and constructed lakes

supply most of the urban water. Farm ponds can be sources of

water in rural communities. The water generally is suitable for

all uses, although some sedimentation problems in surface-mined

areas and local acid mine drainage cause problems in northern

Tennessee and in Kentucky, Virginia, and West Virginia. The

carbonate rocks in Virginia buffer the acid mine drainage, so this

drainage is not a water-quality issue in Virginia.

Large quantities of generally good-quality ground water are

available in some of the larger river valleys in this area, but only

small quantities are locally available in the rest of the area.

Water in the valley of the Kanawha River has levels of iron and

manganese that exceed the national standards for drinking

water. The Pennsylvanian Sandstone aquifer is the primary

bedrock aquifer in this area. This aquifer is called the

Appalachian Plateau aquifer in Virginia and the Middle and

Lower Pennsylvanian aquifer in West Virginia. Water is in the

bedding planes, joints, and fractures in the sandstone, siltstone,

shale, and coalbeds. In Alabama and along the AlabamaTennessee border, the Paleozoic Carbonate aquifer is a source of

ground water. Water is in solution openings and caverns in this

limestone and dolomite aquifer.

The ground water in both aquifers is suitable for all uses.

High iron concentrations occur in water from the coal-bearing

units. The level of total dissolved solids, however, is very low

because of the shallow depth of wells and their location near

the recharge zones for these aquifers. Wells more than 250 to

300 feet (60 to 90 meters) deep provide salty water. The water

from the sandstone is soft, but the water from the carbonate and

shale layers is hard. Some communities in Alabama and

southern Tennessee use both of these aquifers for their water

supply. In the rest of this area, the Pennsylvanian Sandstone

aquifer provides domestic and livestock water. Contamination

from septic systems located too close to domestic wells is one

of the most common water-quality problems in this area.

Soils

Most of the soils in the undulating to rolling areas on the

Cumberland Plateau are Hapludults. Moderately deep or deep,

well drained, loamy Hapludults (Lily, Lonewood, and Hartsells

series) formed in sandstone residuum. Shallow, somewhat

excessively drained, loamy Dystrudepts (Ramsey series) also

formed in sandstone residuum. They are less extensive than the

other soils in the undulating to rolling areas on the Cumberland

Plateau. Most of the remaining soils in the undulating to

rolling areas are deep or very deep, moderately well drained,

loamy Hapludults (Clarkrange and Hendon series), which

formed in a loamy mantle and sandstone residuum. The

dominant soils in hilly to steep areas are Hapludults (Gilpin

and Lily series) and Dystrudepts (Petros and Matewan series).

They are shallow to moderately deep, well drained or somewhat

excessively drained, and loamy and formed in sandstone or

shale residuum. The remaining soils on steep slopes generally

are deep or very deep, well drained, loamy Hapludults

(Bouldin, Grimsley, Jefferson, Pineville, and Shelocta series)

and Dystrudepts (Varilla, Highsplint, and Guyandotte series),

which formed in gravelly or stony colluvium derived from

sandstone and/or shale.

Soils on flood plains are of small extent on the Cumberland

Plateau and are slightly more extensive in the Cumberland

Mountains. Most of these soils are well drained or moderately

well drained Dystrudepts (Ealy, Pope, Philo, and Sewanee

series) or Eutrudepts (Grigsby, Sensabaugh, and Chagrin series)

or poorly drained Endoaquepts (Bonair and Atkins series). They

are deep or very deep, are loamy, and formed in alluvium

derived from sandstone and shale.

Material derived from surface and deep mines is common in

this area. Udorthents (Bethesda, Cedarcreek, Fairpoint, and

Kaymine series) formed in this material.

Biological Resources

This area supports a variety of woody and herbaceous plant

communities. Mixed hardwoods are in coves and on north- and

east-facing slopes. Yellow-poplar, beech, black walnut,

basswood, red oak, white oak, hemlock, and buckeye are

among the 20 or more tree species. Oak-hickory communities,
of the United States 401

shortleaf pine, pitch pine, and Virginia pine are on ridges and

on south- and west-facing slopes. Willows, sycamore,

sweetgum, and river birch grow on flood plains.

Some of the major wildlife species in this area are whitetailed deer, red fox, raccoon, cottontail, muskrat, gray squirrel,

fox squirrel, mink, ruffed grouse, woodcock, bobwhite quail,

and mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 3%

Grassland—private, 10%; Federal, 1%

Forest—private, 73%; Federal, 5%

Urban development—private, 5%

Water—private, 1%

Other—private, 2%

Most of this area consists of small and medium-size farms.

An extensive acreage in Kentucky is in the Daniel Boone

National Forest, and some large tracts are owned by coal and

timber companies. The forested areas support mostly mixed

hardwoods. Lumber is an important product. Corn, hay, and

tobacco are the major crops grown on the small acreage of

cropland in the area. More than one-tenth of the area is pasture,

which is used mostly for grazing by beef cattle. Some areas are

used for urban development. Stabilizing surface-mined areas is

a major management concern.

The major soil resource concerns are water erosion,

deposition of sediment, depletion of organic matter, surface

compaction, and soil contaminants. Conservation practices on

cropland generally include systems of crop residue

management, especially no-till systems; cover crops; and

nutrient management. The most important conservation practice

on pasture is prescribed grazing. Forest management practices

generally include planting and harvesting methods that

minimize disturbance of the surface and minimize surface

compaction. 

Figure 126-1: Location of MLRA 126 in Land Resource Region N.

126—Central Allegheny Plateau

This area (shown in fig. 126-1) is in West Virginia (49

percent), Ohio (28 percent), Pennsylvania (22 percent), and

Kentucky (1 percent). It makes up about 18,040 square miles

(46,750 square kilometers). The cities of Huntington,

Charleston, Parkersburg, Clarksburg, Fairmont, Morgantown,

and Wheeling, West Virginia, and Pittsburgh, Uniontown, and

Indiana, Pennsylvania, are in this area. Steubenville, Marietta,

and Athens, Ohio, also are in this area. Interstates 64, 70, 77,

and 79 cross the area, and Interstate 68 ends in Morgantown,

West Virginia. The Wayne National Forest is in the part of this

area in Ohio. A number of State forests and State parks are

throughout the area.

Physiography

This area is in the Kanawha Section of the Appalachian

Plateaus Province of the Appalachian Highlands. It is on a

dissected plateau that is underlain mainly by horizontally bedded

sedimentary rocks. The narrow, level valleys and narrow, sloping

ridgetops are separated by long, steep and very steep side slopes.

Elevation ranges from 650 feet (200 meters) on the lowest valley

floors to 1,310 feet (400 meters) or more on the highest ridgetops.

Local relief is about 330 feet (100 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Upper Ohio (0503), 48 percent; Monongahela (0502), 19

percent; Kanawha (0505), 10 percent; Muskingum (0504), 9

percent; Middle Ohio (0509), 6 percent; Allegheny (0501), 5

percent; and Big Sandy-Guyandotte (0507), 3 percent. The

Allegheny and Monongahela Rivers join in Pittsburgh to form

the Ohio River. The Ohio River forms the State boundary

between Ohio and West Virginia in this area. The Kanawha and

Little Kanawha Rivers in West Virginia join the Ohio River in

the southern part of the area. The headwaters of the

Monongahela River are in the part of this area in north-central

West Virginia. Some of the major tributaries of the Ohio River

in the Ohio part of the area are the Muskingum, Little

Muskingum, and Hocking Rivers and Duck, Raccoon, and

Symmes Creeks..

Geology

This plateau is underlain mostly by horizontal layers of

Pennsylvanian-age sandstone, siltstone, shale, coal, and some
402 Major Land Resource Areas

limestone. The valleys along the Ohio, Muskingum, and

Kanawha Rivers have significant deposits of river alluvium

(unconsolidated silt, sand, and gravel).

Climate

The average annual precipitation in most of this area is 34 to

45 inches (865 to 1,145 millimeters). It increases to as much as

51 inches (1,295 millimeters) at the higher elevations along the

eastern edge of the area. The precipitation is somewhat

unevenly distributed throughout the year. The maximum occurs

in midsummer, and the minimum occurs in autumn and early in

winter. Rainfall occurs during high-intensity, convective

thunderstorms in summer. The annual snowfall ranges from less

than 35 inches (890 millimeters) to more than 50 inches (1,270

millimeters). The average annual temperature is 48 to 56

degrees F (9 to 13 degrees C). The freeze-free period averages

190 days and ranges from 165 to 215 days. The longer freezefree periods occur in the southwestern part of the area and at the

lower elevations.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 10.9%; ground water, 2.5%

Livestock—surface water, 0.1%; ground water, 0.1%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 78.9%; ground water, 7.4%

The total withdrawals average 5,180 million gallons per day

(19,605 million liters per day). About 10 percent is from ground

water sources, and 90 percent is from surface water sources.

Water from springs, farm ponds, and reservoirs is plentiful. The

surface water in this area generally is suitable for most uses.

Water quality during periods of low flow commonly is a

problem because of contamination. Reservoirs are used to

augment low flows in some areas. Sedimentation and acid mine

drainage from coal mining and industrial and municipal

wastewater discharges cause surface water degradation

throughout the area. Improved environmental practices are

helping to solve these stream-pollution problems. Demands for

surface water for industry, coal mining, and cooling of

thermoelectric power plants can create local shortages. Flows

for navigation take precedence over most water rights, so some

public water suppliers may not obtain all the water they need

for their customers during periods of low flow.

Domestic and agricultural water from wells varies, so storage

tanks are commonly utilized with wells. The Pennsylvanianage sandstone, siltstone, shale, coal, and limestone bedrock in

this area is the primary source of ground water. The water is in

bedding planes, fractures, and joints in most of the rocks in this

aquifer, so low-yield wells are typical. Ground water is in

solution openings in the limestone. This aquifer is called the

Upper Pennsylvanian aquifer in West Virginia, the Shaly

Sandstone and Shale aquifer in Ohio, and the Sandstone and

Shale aquifer in Pennsylvania. The ground water is typically of

good quality and is suitable for all uses. High iron and

manganese cause some esthetic problems involving taste and

staining. Topographic position impacts the water quality in

much of this aquifer. Higher iron and manganese concentrations

are common in wells in valleys as opposed to wells in areas on

hilltops. Where limestone is more common in the eastern half of

this area, the water from valleys is softer than the water from

hilltops, but it has higher sodium concentrations. Large

quantities of ground water can be obtained from deep wells, but

the water generally is highly mineralized.

Some communities and industries obtain ground water from

high-yield wells in the alluvium in the major river valleys in

this area. This water is generally suitable for all uses. It is very

similar in quality to the water in the bedrock, although it is

much harder. Very high concentrations of naturally occurring

manganese are common in wells in the valley along the Ohio

River. Iron and manganese concentrations in the valley along

the Kanawha River greatly exceed national standards for

drinking water. No other significant contamination problems

occur in these sand and gravel aquifers in the area.

Soils

The dominant soil orders in this MLRA are Alfisols, Ultisols,

and Inceptisols. The soils in the area have a mesic soil

temperature regime, a udic soil moisture regime, and mixed

mineralogy. They generally are shallow to very deep,

excessively drained to somewhat poorly drained, and skeletal

to clayey. Dystrudepts (Dekalb and Hazleton series) formed in

sandstone residuum that caps the ridges. Hapludults (Wharton

series) formed on the broader summits. Hapludalfs (Culleoka,

Dormont, Lowell, Peabody, Upshur, and Westmoreland series),

Hapludults (Gilpin series), and Dystrudepts (Weikert series)

formed on the hillsides of red shale, limestone, calcareous

shale, and acid shale. The Dystrudepts on these hillsides are

less extensive than the Hapludalfs and Hapludults. Hapludalfs

(Guernsey, Vandalia, and Beech series) formed in colluvium on

footslopes. Fragiudults (Monongahela series), Dystrudepts

(Philo series), Endoaquepts (Newark series), and Eutrudepts

(Chagrin and Sensabaugh series) formed in alluvium along the

major streams. Udorthents (Bethesda, Fairpoint, and

Morristown series) formed in material derived from the surface

mining of coal.

Biological Resources

This area supports deciduous forest vegetation. White oak,

red oak, black oak, hickory, and associated upland hardwoods

are the major species. Scarlet oak, chestnut oak, and hickory

along with scattered Virginia pine, shortleaf pine, and white

pine grow on dry ridges and on the shallower soils. Yellow-
of the United States 403

poplar, black walnut, red oak, red maple, and other species

requiring much moisture grow in sheltered coves, on

footslopes, and on north-facing slopes.

Some of the major wildlife species in this area are white-tailed

deer, black bear, red fox, raccoon, cottontail rabbit, muskrat, gray

squirrel, pheasant, grouse, and migratory songbirds.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 12%

Grassland—private, 14%

Forest—private, 58%; Federal, 1%

Urban development—private, 11%

Water—private, 2%

Other—private, 2%

Most of this area consists of farms, but less than one-half of

the area consists of income-producing farms. The farm income

is dominantly from beef cattle operations and dairy farms

associated with hay, grassland, and cultivated crops. More than

one-half of the area is forested, and the sale of timber is

important in some areas. Urban expansion, including industrial

and residential development, is increasing along the Ohio River

and its major tributaries. Much of the cropland has been

converted to urban uses. Large acreages are owned or leased for

surface mining of coal.

The major soil resource concerns are sheet and rill erosion

on pasture, land slippage, subsidence resulting from mining,

streambank erosion, gullying, surface compaction caused by

livestock trampling, and a reduced content of organic matter on

cropland. Conservation practices on cropland generally include

crop rotations, contour farming, nutrient management, grassed

and forested riparian buffers, cover crops, hayland planting,

diversions, and grassed waterways. Pasture management

includes rotational grazing, watering systems, fencing, managed

livestock access to streams, pasture planting, and nutrient

management. Forest management includes forest harvest trails,

critical area planting, and water bars on trails. 

Figure 127-1: Location of MLRA 127 in Land Resource Region N.

127—Eastern Allegheny Plateau and

Mountains

This area (shown in fig. 127-1) is in Pennsylvania (57

percent), West Virginia (37 percent), Maryland (4 percent), and

New York (2 percent). It makes up about 19,440 square miles

(50,370 square kilometers). The towns of Warren, Oil City, and

Johnstown, Pennsylvania, and Beckley, West Virginia, are in

this area. Titusville, Pennsylvania, is in the northwest corner of

the area. It was the site of the first well drilled specifically for

oil in the United States in 1859. Cumberland, Maryland, is on

the eastern border of this area. From north to south, Interstates

80, 70/76, 68, and 64 cross the area. The Allegheny National

Forest covers the northern tip of the area, and the Monongahela

National Forest is in the southeast corner. Many State forests

and parks are throughout the area, and half of the Allegany

Indian Reservation is at the northern end of the area.

Physiography

The southern third and northwest corner of this area are in

the Kanawha Section of the Appalachian Plateaus Province of

the Appalachian Highlands. The rest of the area is in the

Allegheny Mountain Section of the same province and

division. The deeply dissected plateau in this area terminates in

a high escarpment, the Allegheny Front, in the eastern part of

the area. Steep slopes are dominant, but level to gently rolling

plateau remnants are conspicuous in the northern part of the

area. Elevation ranges from 980 feet (300 meters) in the lowest

valleys to 1,970 to 2,620 feet (600 to 800 meters) throughout

much of the top of the plateau. It is 3,600 to 4,600 feet (1,100

to 1,400 meters) on the mountains in the southeastern part of

the area. Local relief is mainly about 330 feet (100 meters), but

some mountain peaks in the southern part of the area rise 980

feet (300 meters) or more above the plateau or adjacent valleys.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Allegheny (0501), 28 percent; Susquehanna (0205), 25 percent;

Kanawha (0505), 22 percent; Monongahela (0502), 20 percent;

and Potomac (0207), 5 percent. The New, Cranberry, and

Greenbrier Rivers in West Virginia have been designated

National Wild and Scenic Rivers. The reach of the New River in

the New River Gorge has been designated a National River. The

Youghiogheny National Wild and Scenic River is in Maryland

and continues in Pennsylvania. The Cheat River and the North

Branch of the Potomac River are in West Virginia and
404 Major Land Resource Areas

Maryland. The headwaters of many tributaries to the Allegheny

River to the west and the Susquehanna River to the east are in

the part of this area in Pennsylvania. Some tributaries of the

Kanawha River occur in this MLRA.

Geology

This area consists of alternating beds of sandstone,

limestone, coal, and shale in the uplands. These units are mostly

flat-lying. A few distinct folds and faults are along the

southeastern edge of the part of this area in West Virginia. These

bedrock units are Permian to Mississippian in Pennsylvania

and Pennsylvanian to Cambrian in West Virginia. Coal is mined

throughout most of this area, and oil and gas wells have been

developed. There are no coal mines in the older rocks along the

southeastern edge of this area, in West Virginia. The major river

valleys are filled with unconsolidated deposits of clay, silt,

sand, and gravel, and some outwash and glaciofluvial deposits

are in the river valleys in the northwest corner of this area, in

Pennsylvania. The lower portions of most hills are mantled with

a layer of colluvium.

Climate

The average annual precipitation in this area is 33 to 68

inches (840 to 1,725 millimeters), increasing to the south and

with elevation. The maximum precipitation occurs in spring

and summer, and the minimum occurs in fall. Most of the

rainfall occurs as high-intensity, convective thunderstorms. The

average annual snowfall ranges from 35 inches (890

millimeters) in the southern part of the area to more than 90

inches (2,285 millimeters) in the northern part. The average

annual temperature is 43 to 54 degrees F (6 to 12 degrees C).

The freeze-free period averages 160 days and ranges from 115

to 205 days, decreasing in length to the north and with

elevation.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 2.5%; ground water, 1.9%

Livestock—surface water, 0.1%; ground water, 0.4%

Irrigation—surface water, 0.1%; ground water, 0.0%

Other—surface water, 83.8%; ground water, 11.2%

The total withdrawals average 2,465 million gallons per day

(9,330 million liters per day). About 14 percent is from ground

water sources, and 86 percent is from surface water sources.

Water from farm ponds, reservoirs, and streams is plentiful. The

several large reservoirs in the area include Deep Creek Lake,

the Youghiogheny River Reservoir, and the Allegheny

Reservoir. Deep Creek Lake, the largest reservoir in Maryland,

is a popular summer recreation area. The quality of the surface

water is impaired in a few streams because of acid mine

drainage or municipal and industrial waste discharges.

Ground water is plentiful, although well yields and water

quality are highly variable. Water from alluvium in the major

river valleys in West Virginia commonly is used as drinking

water. It is of good quality and requires little treatment.

In the rest of the area, alternating beds of sandstone,

siltstone, shale, and limestone on uplands of the Appalachian

Plateau are the primary sources of ground water. Coalbeds in

the Pennsylvanian-age rocks also are considered aquifers.

Ground water collected in coal mines commonly is used for

industrial supplies. The water in these bedrock units is in

fractures, in partings along bedding planes, and in solution

openings in limestone. The different rock types and their

elevation impact water quality. Hard water occurs in limestoneand shale-dominated layers, and soft water occurs in sandstonedominated units. The water is freshest on ridgetops where active

recharge occurs. Hardness and levels of iron, manganese, and

total dissolved solids commonly increase from ridgetops to

valley floors. The freshwater in the bedrock is on top of a layer

of brine water, which is typically about 300 feet (90 meters)

below the valley floors.

Manganese concentrations in the bedrock aquifers exceed

the national drinking water standard of 50 parts per billion

(micrograms per liter). The ground water is a calcium

bicarbonate type where the level of total dissolved solids is less

than 300 parts per million (milligrams per liter) and typically is

a calcium sulfate type where the level exceeds 300 parts per

million (milligrams per liter).

Soils

The dominant soil orders in this area are Ultisols and

Inceptisols. The soils dominantly have a mesic or frigid soil

temperature regime, a udic soil moisture regime, and mixed or

siliceous mineralogy. They generally are moderately deep to

very deep, excessively drained to somewhat poorly drained,

and loamy. Fragiudults formed in colluvium on footslopes and

alluvial fans (Buchanan and Ernest series) and in residuum on

ridges (Cookport series). Endoaquults (Cavode series) and

Dystrudepts (Dekalb and Hazleton series) formed in residuum

on hills and ridges. Hapludults (Gilpin, Hartleton, Leck Kill,

Rayne, and Wharton series) formed in residuum and/or till on

hills and ridges. Frigid Dystrudepts (Leatherbark and Mandy

series) and Fragiudepts (Simoda and Snowdog series) are at

high elevations. Udorthents formed in material derived from the

surface mining of coal in mesic areas (Cedarcreek and Kaymine

series) and frigid areas (Briery series).

Biological Resources

This area supports high-quality hardwoods. Oak, black

cherry, yellow-poplar, maple, and other associated hardwoods

are the principal species at the lower elevations. White pine,
of the United States 405

Virginia pine, and black walnut also occur but are of lesser

extent. Red spruce, hemlock, birch, and maple species grow on

the high mountains. Sugar maple, black cherry, and red oak

commonly grow at intermediate elevations.

Some of the major wildlife species in this area are black bear,

white-tailed deer, fox, beaver, raccoon, muskrat, mink,

cottontail, gray squirrel, pheasant, ruffed grouse, woodcock,

and mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 6%; Federal, 1%

Grassland—private, 6%; Federal, 1%

Forest—private, 68%; Federal, 8%

Urban development—private, 5%; Federal, 1%

Water—private, 1%

Other—private, 3%

Most of this area consists of farms. Corn, small grains, and

forage for dairy and beef cattle are the principal crops grown in

the area. Other important crops are potatoes and soybeans.

Dairy, beef, and poultry farms are important enterprises. About

three-fourths of the area is in hardwood forests. Most of the

forestland is privately owned, although the area has large

blocks of State forest and game lands and national forests.

Less than one-tenth of the MLRA consists of urban areas and

disturbed land, including surface-mined areas. Stabilizing

and revegetating surface-mined areas and controlling acid

drainage water from deep mines are major management

concerns.

The major soil resource concerns are sheet and rill erosion

on pasture, land slippage, subsidence caused by mining,

streambank erosion, gullying, surface compaction caused by

livestock trampling, and a reduced content of organic matter on

cropland. Conservation practices on cropland generally include

crop rotations, contour farming, nutrient management, grassed

and forested riparian buffers, cover crops, hayland planting,

diversions, and grassed waterways. Pasture management

includes rotational grazing, watering systems, fencing, managed

livestock access to streams, pasture planting, and nutrient

management. Forest management includes properly constructed

forest harvest trails, critical area planting, and water bars on

trails. 

Figure 128-1: Location of MLRA 128 in Land Resource Region N.

128—Southern Appalachian Ridges and

Valleys

This area (shown in fig. 128-1) is in Tennessee (36 percent),

Alabama (27 percent), Virginia (25 percent), and Georgia (12

percent). It makes up about 21,095 square miles (54,660 square

kilometers). It is heavily populated. It includes Decatur,

Huntsville, and Hartselle in the separate area of the MLRA in

northern Alabama; Scottsboro, Gadsden, Anniston, Talladega,

and Birmingham in the part of the MLRA in northeastern

Alabama; Dalton and Rome, Georgia; Knoxville, Chattanooga,

Cleveland, Athens, Maryville, Oak Ridge, Morristown,

Greeneville, Johnson City, and Bristol, Tennessee; and

Blacksburg and Abingdon, Virginia. Interstates 20, 24, 40, 59,

65, 75, and 81 cross the area. Small areas of the Cherokee

National Forest are on the eastern border of the MLRA, the

Jefferson National Forest is in the part of the MLRA in Virginia,

and the Chattahoochee National Forest is in the part in Georgia.

Small parts of the Talladega National Forest are in the southeast

corner of the area, in Alabama. The Chickamauga and

Chattanooga National Military Park commemorates Civil War

battles near the Georgia and Tennessee border. The National

Aeronautics and Space Administration’s Marshall Space Flight

Center and the Redstone Arsenal and Fort McClellan Military

Reservations are in the part of the area in Alabama. The Oak

Ridge National Laboratory is in the part in Tennessee.

Physiography

Most of this area is in the Tennessee Section of the Valley

and Ridge Province of the Appalachian Highlands. The thin

stringers in the western part of the area are mostly in the

Cumberland Plateau Section of the Appalachian Plateaus

Province of the Appalachian Highlands. A separate area of the

MLRA in northern Alabama is in the Highland Rim Section of

the Interior Low Plateaus Province of the Interior Plains. The

western side of the area is dominantly hilly to very steep and is

rougher and much steeper than the eastern side, much of which

is rolling and hilly. Elevation ranges from 660 feet (200 meters)

near the southern end of the area to more than 2,400 feet (730

meters) in the part of the area in the western tip of Virginia.

Some isolated linear mountain ridges rise to nearly 4,920 feet
406 Major Land Resource Areas

(1,500 meters) above sea level. This area is highly diversified. It

has many parallel ridges, narrow intervening valleys, and large

areas of low, irregular hills. Many ridges and valleys have a

difference in elevation of 660 feet (200 meters).

The extent of the major Hydrologic Unit Areas (identified

by four-digit numbers) that make up this MLRA is as follows:

Upper Tennessee (0601), 37 percent; Alabama (0315), 24

percent; Middle Tennessee-Elk (0603), 12 percent; Middle

Tennessee-Hiwassee (0602), 11 percent; Kanawha (0505), 9

percent; Lower Chesapeake (0208), 3 percent; ChowanRoanoke (0301), 2 percent; and Mobile-Tombigbee (0316), 2

percent. The Tennessee River and its main tributaries, the

Clinch, Holston, Obed, Hiwassee, and Sequatchie Rivers, are in

this area. Two other tributaries in the area, the French Broad and

Little Rivers, have been designated National Wild and Scenic

Rivers. The Tennessee River is one of the largest rivers in the

United States. It is a navigable waterway because of the

numerous locks and dams on the river.

Geology

The bedrock in this area consists of alternating beds of

limestone, dolomite, shale, and sandstone of early Paleozoic

age. Ridgetops are capped with more resistant carbonate and

sandstone layers, and valleys have been eroded into the less

resistant shale beds. These folded and faulted layers are at the

southernmost extent of the Appalachian Mountains. The narrow

river valleys are filled with unconsolidated deposits of clay,

silt, sand, and gravel.

Climate

The average annual precipitation in most of this area is 41 to

55 inches (1,040 to 1,395 millimeters). It increases to the south

and is as much as 66 inches (1,675 millimeters) at the highest

elevations in east Tennessee and the northwest corner of

Georgia. The maximum precipitation occurs in midwinter and

midsummer, and the minimum occurs in autumn. Most of the

rainfall occurs as high-intensity, convective thunderstorms.

Snowfall may occur in winter. The average annual temperature

is 52 to 63 degrees F (11 to 17 degrees C), increasing to the

south. The freeze-free period averages 205 days and ranges

from 165 to 245 days. It is longest in the southern part of the

area and shortest at high elevations and at the northern end.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 6.9%; ground water, 2.4%

Livestock—surface water, 0.3%; ground water, 0.2%

Irrigation—surface water, 0.2%; ground water, 0.3%

Other—surface water, 87.9%; ground water, 1.9%

The total withdrawals average 5,905 million gallons per day

(22,350 million liters per day). About 5 percent is from ground

water sources, and 95 percent is from surface water sources. In

most years precipitation is adequate for crops, but in some years

yields are reduced by short dry periods early in summer.

Permanent streams, originating on either side of the mountains,

carry water to nearly all parts of the area. Several dams,

constructed by the Tennessee Valley Authority on the Tennessee

River and its major tributaries, provide flood control, facilitate

navigation and power production, provide opportunities for

recreation, and provide municipal and industrial water. The

surface water generally is suitable for all uses. Rivers below

reservoirs in this area commonly contain water with low levels

of dissolved oxygen because of the release of water from the

bottom of the reservoirs. This water is very cold, and the

releases can cause water temperature fluctuations, which can

cause problems for fish and wildlife and for recreational uses.

The ground water used in this area is from a Cambrian- to

Mississippian-age carbonate aquifer system that has beds of

limestone, dolomite, shale, and sandstone. The water occurs in

solution openings, joints, and fractures in these units. It is hard

or very hard but is otherwise of excellent quality. Wells in this

aquifer generally are less than 300 feet (90 meters) deep, and

the aquifer is constantly recharged with freshwater (rainfall), so

the level of total dissolved solids is fairly low for a carbonate

aquifer. The median level of total dissolved solids is about 150,

126, and 270 parts per million (milligrams per liter) in Alabama,

Georgia, and Tennessee, respectively. High levels of iron occur

in some areas, such as the areas in the part of this MLRA in

Tennessee. These high levels of iron may exceed the national

secondary standard for drinking water, which is 300 parts per

billion (micrograms per liter). The secondary standard is

esthetic. The iron can stain ceramic and porcelain and

precipitate in pipes. Since this aquifer is close to the surface

and water moves through it quickly, it is highly susceptible to

contamination from runoff. Many communities and rural

landowners in areas away from surface water supplies rely on

this aquifer for drinking water.

Soils

The soils in this area are mainly Udults and, to a lesser

extent, Udepts. They have a udic soil moisture regime and a

thermic or mesic soil temperature regime; are dominantly well

drained, strongly acid, and highly leached; and have a clayenriched subsoil. They range from shallow on sandstone and

shale ridges to very deep in valleys and on large limestone

formations.

Paleudults (Decatur, Dewey, Frederick, Fullerton, and Pailo

series, commonly cherty) are in the many extensive areas

underlain by limestone that traverse the MLRA from southwest

to northeast. Hapludults (Townley and Armuchee series) are

dominant in valleys underlain by acid shale. Steep, shallow or

moderately deep, shaly and stony Dystrudepts (Weikert,
of the United States 407

Wallen, Montevallo, and Calvin series) are on the sides of steep

ridges. Shallow, shaly Eutrudepts (Bays and Dandridge series)

are in areas of the shale formation extending along the eastern

side of the MLRA. Eutrudepts (Hamblen, Sullivan, and

Pettyjon series) are on narrow bottom land.

Biological Resources

This area supports hardwoods or mixed hardwoods and pine.

The deeper soils support good oak-hickory stands. The

shallower soils, mostly on south and west aspects, support pine

or oak-pine types. The understory vegetation also is affected by

aspect. Little bluestem is the dominant grass species.

Some of the major wildlife species in this area are red fox,

gray fox, raccoon, skunk, opossum, muskrat, mink, cottontail,

gray squirrel, fox squirrel, bobwhite quail, and mourning dove.

The species of fish in the area include carp, bullhead,

largemouth bass, and bluegill.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 12%

Grassland—private, 21%; Federal, 1%

Forest—private, 41%; Federal, 2%

Urban development—private, 16%

Water—private, 5%

Other—private, 2%

Most of this area consists of small and medium-size

farms. More than two-fifths of the area supports mixed

hardwoods. Most of the forestland, except for a few wooded

mountain ridges, is in small farm woodlots. Hay, pasture, and

some grain for beef cattle and dairy cattle are the principal

crops grown in this area. Burley tobacco is the important cash

crop in the southern two-thirds of the area, excluding Georgia.

Some cotton is grown south of Chattanooga. Corn and

soybeans are grown on small acreages throughout the area,

mainly in narrow strips of bottom land and on the adjacent low

terraces.

The major soil resource concerns are sheet and rill erosion

on pasture, land slippage, streambank erosion, gullying, surface

compaction caused by livestock trampling, and a reduced

content of organic matter on cropland. Conservation practices

on cropland generally include crop rotations, contour farming,

nutrient management, grassed and forested riparian buffers,

cover crops, hayland planting, diversions, and grassed

waterways. Pasture management includes rotational grazing,

watering systems, fencing, managed livestock access to streams,

pasture planting, and nutrient management. Forest management

includes properly constructed forest harvest trails, critical area

planting, and water bars on trails. 

Figure 129-1: Location of MLRA 129 in Land Resource Region N.

129—Sand Mountain

This area (shown in fig. 129-1) is in Alabama (96 percent),

Georgia (3 percent), and Tennessee (1 percent). It makes up

about 8,030 square miles (20,805 square kilometers). The towns

of Jasper, Cullman, and Fort Payne, Alabama, are in this MLRA.

Interstate 65 crosses this area from north to south, and

Interstates 24 and 59 join in the area just west of Chattanooga,

Tennessee, which is just outside the northeast tip of the MLRA.

Areas of the Redstone Arsenal Military Reservation are in the

northern part of the MLRA. The William B. Bankhead National

Forest and the Sipsey National Forest Wilderness are in the

western part.

Physiography

Most of this area is in the Cumberland Plateau Section of the

Appalachian Plateaus Province of the Appalachian Highlands.

This MLRA is deeply dissected and consists mainly of a series

of rather narrow valleys, steep escarpments, and broad plateaus

that are underlain by consolidated bedrock. Elevation ranges

from 330 to 2,300 feet (100 to 700 meters). Valley floors are

commonly about 100 to 400 feet (30 to 120 meters) below the

adjacent plateau summits, but local relief may be as much as

1,200 feet (365 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Mobile-Tombigbee (0316), 50 percent; Middle Tennessee-Elk

(0603), 25 percent; Alabama (0315), 21 percent; and Middle

Tennessee-Hiwassee (0602), 4 percent. The Sipsey Fork, Locust

Fork, and Mulberry Fork Rivers, headwaters of the Black

Warrior River, are in this area. The Tennessee River forms part

of the northern boundary of the area.
408 Major Land Resource Areas

Geology

The bedrock in this area consists of alternating beds of

limestone, dolomite, shale, and sandstone of early Paleozoic age

(mostly Mississippian and Pennsylvanian age). The summits of

ridges and plateaus are capped with the more resistant

carbonate and sandstone layers, and valleys have been eroded

into the less resistant shale beds. These mostly level-bedded

sedimentary rocks are at the southernmost extent of the

Appalachian Mountains. The narrow river valleys are filled

with unconsolidated deposits of clay, silt, sand, and gravel.

Climate

The average annual precipitation in most of this area is 53 to

60 inches (1,345 to 1,525 millimeters). It is as much as 68

inches (1,725 millimeters) at the higher elevations in the

northern tip of the area. The precipitation is somewhat

unevenly distributed throughout the year. The maximum occurs

in midwinter, and the amount decreases gradually from spring

to autumn and increases slightly in midsummer. Winter rainfall

occurs as moderate-intensity, tropical storms that can produce

large amounts of rain. During the rest of the year, rainfall occurs

as high-intensity, convective thunderstorms. Snowfall is rare in

winter, and the snow does not remain on the ground for long

periods. The average annual temperature is 55 to 63 degrees F

(13 to 17 degrees C). The freeze-free period averages 225 days

and ranges from 200 to 255 days. The longer freeze-free periods

occur in some of the valleys.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 8.3%; ground water, 2.5%

Livestock—surface water, 0.8%; ground water, 0.7%

Irrigation—surface water, 0.1%; ground water, 0.4%

Other—surface water, 86.6%; ground water, 0.6%

The total withdrawals average 1,225 million gallons per day

(4,635 million liters per day). About 4 percent is from ground

water sources, and 96 percent is from surface water sources. In

most years precipitation is adequate for crops and pasture.

Droughts are short and infrequent. Streams, springs, and ponds

provide water for livestock. Most streams flow intermittently

and are often dry in summer and autumn, except after

rainstorms. A few large reservoirs on the Elk and Tennessee

Rivers are in the area. The surface water is suitable for almost

all uses. Rivers below the reservoirs in this area commonly have

water with low levels of dissolved oxygen because of the

release of water from the bottom of the reservoirs.

Deep wells provide an adequate supply of water for most

domestic, municipal, and industrial uses. Good-quality ground

water occurs in solution channels in limestone and dolomite

and in fractures and partings along bedding planes in shale and

sandstone bedrock layers. The ground water is very hard, and

the median level of total dissolved solids is about 150 parts per

million (milligrams per liter). This Paleozoic aquifer system is

susceptible to contamination from surface sources because of

the vertical fractures and the cavernous limestone and dolomite

layers. The median level of nitrates, 1.3 parts per million

(milligrams per liter), is about four times greater than the

median level in any other aquifer in this area.

Soils

The dominant soil orders in this MLRA are Ultisols and

Inceptisols. The soils in the area dominantly have a thermic soil

temperature regime, a udic soil moisture regime, and mixed or

siliceous mineralogy. They are shallow to very deep, generally

well drained, and loamy. Hapludults (Albertville, Hartsells,

Gorgas, Linker, Nauvoo, Sipsey, Sunlight, and Townley series),

Fragiudults (Wynnville series), Dystrudepts (Bankhead, Hector,

and Montevallo series), and Eutrudepts (Limrock series) formed

in residuum on hills, ridges, and plateaus and in residuum and

colluvium on mountainsides.

Biological Resources

This area supports mixed oak, hickory-pine, and oakhickory forests. Shortleaf pine, loblolly pine, Virginia pine,

sweetgum, yellow-poplar, hickory, American beech, red oak,

and white oak are the major overstory species. Dogwood and

redbud are the major midstory species. Japanese honeysuckle,

greenbrier, low panicums, bluestems, and native lespedezas are

the major understory species.

Some of the major wildlife species in this area are whitetailed deer, fox, bobcat, raccoon, skunk, opossum, mink, rabbit,

gray squirrel, quail, and mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 7%

Grassland—private, 14%; Federal, 1%

Forest—private, 60%; Federal, 3%

Urban development—private, 9%

Water—private, 3%

Other—private, 3%

Almost two-thirds of this area is forestland, less than onetenth is cropland, and more than one-tenth is pasture. About

three-fifths of the forestland is privately owned, about onetenth is industry owned, and less than one-tenth is federally

owned. Timber production occurs mostly in the western half of

the area. The poultry industry, which produces broilers and
of the United States 409

eggs, is the major farm enterprise. Corn, soybeans, tomatoes,

and potatoes are the major cash crops. Pastures are grazed

mainly by beef cattle and are important disposal areas for

poultry waste. Haying provides feed during the long winters.

Some areas are used for coal mining or urban development.

The major soil resource concerns are water erosion,

maintenance of the content of organic matter and productivity

of the soils, and management of soil moisture. Conservation

practices on cropland generally include crop residue

management, cover crops, crop rotations, water disposal, pest

management, and nutrient management. The most important

conservation practice on pasture is prescribed grazing.

Critically eroding areas and areas of livestock concentration

must be monitored regularly and treated promptly. 

Figure 130A-1: Location of MLRA 130A in Land Resource Region N.

130A—Northern Blue Ridge

This area (shown in fig. 130A-1) is in Virginia (61 percent),

Pennsylvania (22 percent), Maryland (14 percent), and West

Virginia (3 percent). It makes up about 1,555 square miles

(4,030 square kilometers). It is locally known as the Northern

Appalachians. It includes the towns of Boonsboro and

Thurmont, Maryland; Harpers Ferry, West Virginia; Blue Ridge

Summit, Wenksville, and Laurel, Pennsylvania; and Buena

Vista and Front Royal, Virginia. The city of Roanoke, Virginia,

is in the southern end of the MLRA. Interstates 64, 66, 70, and

81 cross this area. The area is rich in colonial and Civil War

historical sites. The George Washington Monument State Park

is in the part of the area in Maryland. Harpers Ferry National

Historic Park is in the part in West Virginia. The Chesapeake

and Ohio Canal National Historic Park parallels the Potomac

River on the Maryland-Virginia border. The Shenandoah

National Park, the Blue Ridge Parkway, and the Jefferson and

George Washington National Forests are major recreation areas

in the part of the MLRA in Virginia. The Appalachian Trail also

is in this MLRA.

Physiography

Most of this area is in the Northern Section of the Blue

Ridge Province of the Appalachian Highlands. The eastern

third of the area is in the Piedmont Upland Section of the

Piedmont Province of the Appalachian Highlands. The southern

tip of the area is in the Southern Section of the Blue Ridge

Province of the Appalachian Highlands. The rugged mountains

in this MLRA have steep slopes, sharp crests, and narrow

valleys. Stream dissection is deep and intricate. The major

streams and their tributaries flow through gorges and gaps in

the mountains. Broad valleys and basins and rolling hills are

extensive throughout the area. Elevation ranges from about 820

feet (250 meters) in the lower valleys and on footslopes along

the Potomac River just east of Harpers Ferry, where West

Virginia joins Maryland and Virginia, to more than 4,200 feet

(1,280 meters) along the Appalachian Trail in Bedford County,

Virginia. Apple Orchard Mountain, the highest peak, is at an

elevation of 4,225 feet (1,288 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Chowan-Roanoke (0301), 33 percent; Lower Chesapeake

(0208), 32 percent; Potomac (0207), 23 percent; and

Susquehanna (0205), 12 percent. From north to south, the major

rivers in this area are the Conococheaque River in

Pennsylvania, the Catoctin and Potomac Rivers in Maryland,

and the Shenandoah, Rappahannock, Rapidan, James, and

Roanoke Rivers in Virginia. Catoctin and Goose Creeks and the

Shenandoah and Rappahannock Rivers have been designated

National Wild and Scenic Rivers in this area.

Geology

This area includes the eroded core of the Appalachian

Mountains, formed during a period of post-Cretaceous uplift

along the east coast of North America. The part of the area that

extends into Maryland and Pennsylvania, including the South

and Catoctin Mountains, is the northeast plunging nose of the

Catoctin-Blue Ridge anticline. This is an old fold exposed

during the latest uplift. A resistant, Late Proterozoic to

Cambrian cover sequence that includes chlorite-actinolite

schist, schistose metabasalt, siliceous metabreccia, laminated

metasedimentary gneiss, quartzite, phyllitic, and rhyolitic

layers forms linear ridges that flank the coarse grained granitoid

and gneissic basement rocks exposed in the Proterozoic core of

the anticline in northern Virginia. In central Virginia, the Blue

Ridge has a series of upthrust crystalline shingle blocks of

resistant granite, augen gneiss, or quartzite where narrow fault
410 Major Land Resource Areas

valleys are underlain by less resistant mylonitic gneiss and

schist units. Surficial Pleistocene deposits and more recent

deposits include colluvial material on fans and aprons along

the higher ridges and alluvial material along the major streams.

Climate

The average annual precipitation in most of this area is 36 to

45 inches (915 to 1,145 millimeters). It can be as high as 61

inches (1,550 millimeters) at the higher elevations. Snow

covers the ground frequently in winter and is a major

contributor to the annual amount of precipitation. The average

annual temperature is 49 to 56 degrees F (9 to 14 degrees C).

The freeze-free period averages 195 days and ranges from 165

to 225 days. The lower average annual temperatures and shorter

freeze-free periods occur at the higher elevations.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 13.2%; ground water, 1.9%

Livestock—surface water, 0.8%; ground water, 0.4%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 74.0%; ground water, 9.7%

The total withdrawals average 330 million gallons per day

(1,250 million liters per day). About 12 percent is from ground

water sources, and 88 percent is from surface water sources.

Streams, some ponds, and springs provide water for livestock.

Springs also provide some domestic drinking water. The many

rivers crossing this area are sources of public supply and

industrial water. Most of this water is of good quality and is

suitable for most uses. Limited use is made of the water from the

South Fork of the Shenandoah River at the north end of this

area because of residual mercury from historic industrial waste

discharges.

Springs and shallow wells provide domestic water in rural

areas, but the yield of ground water from wells is generally

small and variable. The water is in joints and fractures in the

rocks, so deep wells are required to intercept enough openings

to obtain a suitable yield. The abundance of ground water

depends largely on landscape position and geology. The most

abundant sources are in coves and valleys. The water sources

on side slopes and ridge summits are not so abundant or

dependable. The primary source of domestic ground water in

this area is the Piedmont and Blue Ridge crystalline rock

aquifer in Virginia and Maryland. It consists of intrusive

igneous and metamorphic rocks. The water from this aquifer has

very low levels of total dissolved solids and is generally soft or

moderately hard. It generally is acidic, however, and the acidity

can damage copper and lead in pipes and plumbing

connections. The iron content and hardness vary with the

mineralogy of the source rocks, and naturally high radiation

levels are common. The Sandstone and Shale aquifer is the

primary source of ground water in the northern end of this

area, in Pennsylvania. The quality of the water in this aquifer

is similar to that of the water in the Piedmont and Blue Ridge

crystalline rock aquifer to the south, but radiation contamination

is not a problem in the sedimentary rocks in Pennsylvania.

Soils

The dominant soils in this MLRA are Dystrudepts,

Hapludults, Hapludalfs, or Kanhapludults. They range from

moderately deep to very deep and from loamy-skeletal and

sandy-skeletal to clayey (fine textured). The soils have a mesic

soil temperature regime, a udic soil moisture regime, and

dominantly mixed mineralogy. Dystrudepts (Brandywine,

Hazel, Peaks, Cataska, and Sylco series) and Hapludults

(Edneytown and Edgemont series) are the principal low-fertility

soils on the steep slopes of mountains. More fertile Hapludalfs

(Myersville and Highfield series) and Eutrudepts (Catoctin

series) are equally prominent on these slopes. Hapludults

(Thurmont and Braddock series) formed in colluvium on

footslopes and in coves. Kanhapludults (Hayesville series) are

on the broader and flatter residual summits and shoulders and

on the less steep side slopes. In some areas boulders and

outcrops of bedrock are extensive on mountain slopes.

Dystrudepts (Comus and Codorus series) are along the many

narrow streams that flow through, and out of, the area. These

soils are frequently flooded unless they are protected.

Biological Resources

This area supports Appalachian oaks. White pine-hemlock,

chestnut oak, white oak-red oak-hickory, northern red oakbasswood-white ash, yellow-poplar-white oak-northern red oak,

and loblolly pine-shortleaf pine are the most common cover

types. Dogwood, hornbeam, pawpaw, sassafras, persimmon,

greenbrier, leatherwood, mountain laurel, rhododendron, and

witch hazel are included in the understory.

The major large mammal species in this area are raccoon,

white-tailed deer, coyote, beaver, black bear, red fox, gray fox,

and bobcat. The smaller mammal species include white-footed

mouse, eastern chipmunk, gray squirrel, and eastern cottontail.

The area has numerous species of birds. Open areas, fences,

riparian strips, forests, wetlands, ponds, and rocky areas

maintain this avian diversity. The area has three species of

trout—the native Southern Appalachian brook trout and the

introduced rainbow trout and brown trout. Smallmouth and

largemouth bass, sunfish, bluegills, and crappies are in some of

the manmade lakes and ponds. This area provides excellent

habitat for snakes, turtles, frogs, newts, toads, and salamanders.
of the United States 411

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 10%

Grassland—private, 17%

Forest—private, 49%; Federal, 10%

Urban development—private, 9%

Water—private, 2%; Federal, 1%

Other—private, 2%

About three-fifths of this area is forested. About one-fifth of

the area consists of national parks and forests. Parts of the area

are popular resort and recreation sites. About one-tenth of the

area is cropland, mainly on small farms in valleys and coves,

and one-sixth is pasture. Corn and hay are the chief crops, but

small grains, potatoes, and many kinds of fruits and vegetables

also are grown. Tobacco is an important crop in some areas.

Most of the farms are part-time enterprises, and the occupants

earn a large part of their livelihood elsewhere.

Erosion along poorly constructed and maintained access

roads is a major management concern in this area. Sediment

from access roads and urban development is the main pollutant

of streams in the area. This sedimentation not only is harmful to

aquatic life but also impacts local economies that are

dependent on tourism and recreational industries. With

increasing urbanization, access roads and homes have been built

in marginally suitable areas, such as steep side slopes. Because

of improper site preparation in these areas, the hazards of

sedimentation, soil slippage, and slope instability are

increased.

Poor air quality, especially in summer, is both a health and

economic problem. Air pollution flowing from the industrial

Midwest affects people who are sensitive to pollutants, such as

ozone, and those who suffer from breathing disorders.

Decreased visibility from air pollution impacts the tourism

industry. Air quality also is a concern in urbanized

intermountain basins where thermal inversions trap pollutants.

Proper woodland management is extremely important since

privately held forestland makes up a significant portion of the

land area in the MLRA. Promotion and use of the best

management practices among private landowners can help to

maintain timber quality and productivity. Proper design and

construction of access roads and stabilization of roadbanks can

minimize the impact of timber management on water quality.

Conservation practices on cropland generally include field

borders, grassed waterways, diversions, and riparian buffers

along streams. Prescribed grazing and proper forage, nutrient,

and pest management practices are critical in maintaining the

productivity of grazing land.

In areas where streams have been channelized, riparian areas

have been removed, and livestock access is unchecked,

streambank erosion is a major concern. Stabilizing streambanks

and channels and restoring and maintaining riparian forest

buffers help to maintain or improve water quality. The

condition of streambanks and channels becomes increasingly

important in managing the storm-water runoff from growing

urban areas. 

Figure 130B-1: Location of MLRA 130B in Land Resource Region N.

130B—Southern Blue Ridge

This area (shown in fig. 130B-1) is in North Carolina (51

percent), Tennessee (18 percent), Georgia (17 percent), Virginia

(10 percent), and South Carolina (4 percent). It makes up about

16,080 square miles (41,665 square kilometers). It is locally

known as the Southern Appalachians. It includes Lenoir,

Morganton, Marion, Hendersonville, Waynesville, and

Asheville, North Carolina; Gatlinburg, Tennessee; Damascus

and Galax, Virginia; Walhalla, South Carolina; and Cleveland,

Dahlonega, and Ellijay, Georgia. Interstate 40 crosses the parts

of the area in Tennessee and North Carolina. Interstate 77

crosses the part in Virginia. Many national forests are in the

area, including the Jefferson, Cherokee, Nantahala, Pisgah, and

Chattahoochee National Forests. The Appalachian Trail begins

on Springer Mountain in Georgia, near Amicalola State Park.

The Great Smoky Mountains National Park is in this MLRA.

The Mount Rogers National Recreation Area is in the part of

the MLRA in Virginia. The Cherokee Indian Reservation is

west of Waynesville, North Carolina.

Physiography

This MLRA is mainly in the Southern Section of the Blue

Ridge Province of the Appalachian Highlands. The southern tip

of the MLRA and two protruding areas to the east are in the

Piedmont Uplands Section of the Piedmont Province of the

Appalachian Highlands. This MLRA consists of several distinct

topographic areas, including the Blue Ridge Escarpment on the
412 Major Land Resource Areas

eastern edge of the area, the New River Plateau on the northern

end, interior low and intermediate mountains throughout the

MLRA, intermountain basins between the major mountains,

and the high mountains making up the bulk of the MLRA.

Elevation ranges from about 900 feet (275 meters) at the south

and southwest boundaries of the area to more than 6,600 feet

(2,010 meters) at the crest of the Great Smoky and Black

Mountain ranges.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Upper Tennessee (0601), 46 percent; Kanawha (0505), 13

percent; Middle Tennessee-Hiwassee (0602), 12 percent;

Edisto-Santee (0305), 9 percent; Alabama (0315), 8 percent;

Ogeechee-Savannah (0306), 6 percent; Pee Dee (0304), 4

percent; Chowan-Roanoke (0301), 1 percent; and Apalachicola

(0313), 1 percent. From north to south, the major rivers in this

area are the New River in Virginia; the Yadkin, Catawba, French

Broad, Little Tennessee, and Hiwassee Rivers in North

Carolina; the Saluda, Seneca, Chattooga, and Tugaloo Rivers in

South Carolina; and the Toccoa and Coosawattee Rivers in

Georgia. The Tugaloo River is a headwater stream of the

Savannah River, and the French Broad, Little Tennessee,

Hiwassee, and Ocoee Rivers also flow into Tennessee in this

area. The Hiwassee River in Tennessee and the Conasauga

River in Georgia have been designated National Wild and

Scenic Rivers in this area. The Chattooga River in South

Carolina is a National Scenic River.

Geology

The bedrock geology in this area consists mostly of

Precambrian metamorphic rock formations with a few small

bodies and windows of igneous and sedimentary rocks. The

degree of metamorphism varies but generally decreases

westward. The higher grade metamorphic rocks include

formations of gneiss, schist, and amphibolite. Low-grade

metamorphic formations in the southwestern part of the MLRA

include distinct and interbedded bodies of metasandstone, slate,

phyllite, metasiltstone, and metaconglomerate. Surficial

deposits include colluvial material on fans and aprons along the

ridges and alluvial material along the major streams.

Climate

The average annual precipitation in this area generally is 36

to 60 inches (915 to 1,525 millimeters), generally increasing

with elevation. It is 60 to 90 inches (1,525 to 2,285 millimeters)

in southwestern North Carolina and northeastern Georgia and

can be as much as 119 inches (3,025 millimeters) on the higher

peaks in the MLRA. Much of the precipitation occurs as snow

at the higher elevations. The amount of precipitation is lowest

in the fall. The average annual temperature ranges from 46 to

60 degrees F (8 to 16 degrees C), decreasing with elevation.

The freeze-free period averages 185 days and ranges from 135

to 235 days. The freeze-free period is shorter at high elevations

and on valley floors because of cold air drainage. Microclimate

differences resulting from aspect significantly affect the type

and vigor of the plant communities in the area. South- and

west-facing slopes are warmer and drier than north- and eastfacing slopes and those shaded by the higher mountains.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 4.6%; ground water, 1.8%

Livestock—surface water, 4.4%; ground water, 1.0%

Irrigation—surface water, 0.2%; ground water, 0.1%

Other—surface water, 85.3%; ground water, 2.7%

The total withdrawals average 710 million gallons per day

(2,685 million liters per day). About 6 percent is from ground

water sources, and 94 percent is from surface water sources.

Streams, some ponds, and springs provide water for livestock.

Springs also supply some domestic drinking water. The many

rivers crossing this area are sources of public supply and

industrial water. The Tennessee Valley Authority, Duke Power,

and Alcoa operate several reservoirs and dams for electric

power production, flood control, water supply, and recreation.

Protected watersheds and reservoirs supply water to municipal

areas. These watersheds commonly are protected lands

managed by the U.S. Forest Service and are sources of highquality water. Most of the water is of excellent quality and is

suitable for most uses. Acid-mine drainage from coal mines in

the Appalachian Plateau to the west of the northern end of this

area causes some contamination in rivers draining that area.

The limestone bedrock underlying these drainages, however,

provides enough carbonates in runoff water to mitigate most of

the contamination, so this surface water is still usable within

this area. Wastewater discharges from textile, wood, and paper

mills in North Carolina can cause some local water-quality

problems.

Springs and shallow wells provide domestic water in rural

areas, but the yields of ground water from wells are generally

small and variable. The water is in joints and fractures within

the rocks, so deep wells are required to intercept enough

openings to obtain a suitable yield. The abundance of ground

water depends largely on landscape position and geology. The

most abundant sources generally are in coves and valleys. The

sources on side slopes and ridge summits are not so abundant or

dependable. The primary source of domestic ground water in

this area is the Piedmont and Blue Ridge crystalline rock

aquifer in Virginia and South Carolina or the Crystalline Rock

aquifer in the other States in the area. It consists of intrusive

igneous and metamorphic rocks. This water has very low

levels of total dissolved solids and is generally soft or

moderately hard. In Virginia, it generally is acidic, and the

acidity can damage copper and lead in pipes and plumbing
of the United States 413

connections. The iron content and hardness vary with the

mineralogy of the source rocks. Iron levels are generally less

than 300 parts per billion (micrograms per liter), which is the

national secondary standard (for esthetics) for drinking water.

The median level of iron in the ground water in Tennessee is

twice the level in the ground water in the other States in the

area. Naturally high radiation levels are common in the ground

water in Virginia.

Soils

The dominant soil orders in this MLRA are Inceptisols and

Ultisols. The soil moisture regime is udic. The soil temperature

regime typically is mesic, but it is frigid at elevations above

4,200 feet (1,280 meters). Soil depth ranges from shallow to

very deep. The general textural class is loamy or clayey.

In areas at elevations of less than 3,500 feet (1,065 meters),

the soils on uplands generally are red, fine-loamy or fine Typic

Hapludults (Evard, Junaluska, and Hayesville series). Humic

Hapludults (Trimont and Snowbird series) are on north and east

aspects. Soils that formed in colluvium in coves are Typic

Dystrudepts (Tate, Greenlee, and Northcove series), Typic

Hapludults (Lonon and Keener series), or Humic Hapludults

(Saunook and Thunder series).

At elevations between 3,500 and 4,200 feet (1,065 and 1,280

meters), the soils on uplands generally are brown, fine-loamy or

coarse-loamy Dystrudepts. Humic Dystrudepts (Plott, Porters,

and Cheoah series) are common on north and east aspects, and

Typic Dystrudepts (Edneyville, Chestnut, Ditney, and Stecoah

series) are common on south and west aspects. Soils that formed

in colluvium in coves are Humic Dystrudepts (Cullasaja,

Spivey, Tuckasegee, and Santeetlah series) or Humic

Hapludults (Saunook and Thunder series).

In areas at elevations above 4,200 feet (1,280 meters), the

soils on uplands generally are brown, fine-loamy or coarseloamy Humic Dystrudepts with a frigid soil temperature regime

(Burton, Oconaluftee, and Breakneck series). Soils that formed

in colluvium also are Humic Dystrudepts (Balsam and

Chiltoskie series). Soils that formed in alluvium vary with

stream gradient, energy, and entrenchment into the valley floor.

In the upper reaches of watersheds where flood plains are

narrow, the soils are Oxyaquic and Fluvaquentic Dystrudepts

(Dellwood, Reddies, and Cullowhee series). In the lower and

broader river valleys, Udipsamments (Biltmore series) and

coarse-loamy Dystrudepts (Rosman series) are in areas closest

to rivers and streams on flood plains. Humaquepts (Ela,

Nikwasi, and Toxaway series) are in low-lying, frequently

flooded or ponded areas. Ultisols are most common on the

more stable stream terraces. Fine-loamy Aquic and Typic

Hapludults (Dillard and Statler series) are on low terraces, and

fine Typic Hapludults (Braddock and Unison series) are on high

terraces.

Biological Resources

This area supports a wide diversity of plant and animal life

because of highly varied topography and climatic conditions.

The kind of vegetation changes with elevation and slope aspect.

At the lower elevations, below 3,000 feet (915 meters), the most

common trees are white oak, black oak, scarlet oak, chestnut oak,

hickory, eastern white pine, Virginia pine, and pitch pine. Yellowpoplar and northern red oak are common in the northern part of

the MLRA. At the middle elevations, the most common trees are

yellow-poplar, black cherry, black birch, sugar maple, northern red

oak, American basswood, eastern hemlock, and yellow buckeye.

At the higher elevations, above 5,000 feet (1,525 meters), red

spruce and Fraser fir are the dominant tree species. In some areas

at a high elevation, grassy and heath “balds” are evident. These

are large meadows or treeless areas. Grassy balds are dominated by

grass species and are home to rare shade-intolerant plant varieties.

Heath balds support shrubs, such as rhododendron, mountain

laurel, blueberry, flame azalea, hawthorn, huckleberry, and sand

myrtle.

The diverse plant communities provide habitat for many

species of wildlife. Black bear, white-tailed deer, and wild

turkey are plentiful. The higher elevations provide suitable

habitat for the birds and animals that are common in northern

latitudes, such as northern saw-whet owl, Canada warbler,

common raven, northern flying squirrel, and red squirrel.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 4%

Grassland—private, 10%; Federal, 3%

Forest—private, 46%; Federal, 23%

Urban development—private, 8%; Federal, 1%

Water—private, 2%; Federal, 1%

Other—private, 1%; Federal, 1%

More than two-thirds of this area is forestland used for

timber production, watershed protection, recreation, and

wildlife habitat. The federally owned forestland in the area is

mainly U.S. Forest Service or National Park Service land. The

small acreage of cropland is used for vegetables, fruit orchards,

native ornamental crops, and Christmas trees as well as corn

and small grain. About 10 percent of the MLRA is in pastured

areas used for dairy, beef, and wool production. The largest

urban area in this MLRA is Asheville, North Carolina. The

MLRA is a popular area for tourism and retirement living. As a

result, steady or rapid urban growth occurs in many areas.

Erosion from poorly constructed and maintained access

roads is a major management concern in this area. Sediment

from access roads and urban development is the main pollutant

of streams in the area.
414

Poor air quality, especially in summer, is both a health and

economic problem. Air pollution flowing from the industrial

Midwest affects people who are sensitive to pollutants, such

as ozone, and those who suffer from breathing disorders. At

high elevations, air pollution and acid deposition are thought

to be partially responsible for damage to the spruce and fir

forests.

Proper woodland management is extremely important since

privately held forestland makes up a significant portion of the

land area in this MLRA. Proper design and construction of

access roads and stabilization of roadbanks can minimize the

impact of timber management on water quality.

Conservation practices in agricultural areas include field

borders, grassed waterways, diversions, and riparian buffers

along streams. Prescribed grazing and proper forage, nutrient,

and pest management practices are critical in maintaining the

productivity of grazing land.

In areas where streams have been channelized, riparian areas

have been removed, and livestock access is unchecked,

streambank erosion is a major concern. Stabilizing streambanks

and channels and restoring and maintaining riparian forest

buffers can maintain or improve water quality. The condition of

streambanks and channels becomes increasingly important in

managing the storm-water runoff from growing urban areas. 
415

Figure O-1: Location of Land Resource Region O.

O—Mississippi Delta Cotton and Feed

Grains Region

Nearly all of this region (shown in fig. O-1) is in Arkansas

(35 percent), Louisiana (34 percent), Mississippi (20 percent),

Missouri (9 percent), and Tennessee (2 percent). Very small

areas of the region are in Kentucky and Illinois. The region

makes up 38,865 square miles (100,710 square kilometers).

Fertile soils, smooth topography, abundant moisture, and a

long growing season favor agricultural production in this

region. If crops are to be grown, artificial drainage typically is

needed to lower the water table. Levees are used to protect

cropland from flood damage.

This region is on smooth terraces and flood plains along the

Mississippi River and its major tributaries south of its

confluence with the Ohio River. The geologic material in the

region consists of very thick deposits of sandy to clayey

alluvium of Pleistocene to Holocene age. This material was

deposited by the rivers. Local relief is typically less than 15

feet (5 meters).

The climate in this region is hot and humid. It is

characterized by long, hot summers and short, mild winters. The

mean annual precipitation is 47 to 62 inches (1,195 to 1,575

millimeters), generally increasing from north to south. The

precipitation falls almost entirely as rainfall during frontal

storms in late fall, winter, and early spring; as rainfall occurring

as convective storms during the growing season; and as heavy

rainfall produced by tropical storms. The mean annual air

temperature throughout most of the region is 60 to 67 degrees F

(15 to 19 degrees C). The freeze-free period ranges from 235 to

305 days. The mean annual air temperature and the length of

the freeze-free period increase from north to south.

The total withdrawals of freshwater in this region average

about 11,130 million gallons per day (43,300 million liters per

day). About 55 percent is from ground water sources, and 45
416 Major Land Resource Areas

Figure O-2: Levee and rice in an area of Land Resource Region O.

percent is from surface water sources. About 57 percent of the

water is used for irrigation, and 37 percent is used for industry

and for cooling thermoelectric power plants.

The soils in this region are dominantly Alfisols, Vertisols,

Inceptisols, or Entisols. Aqualfs and Aquerts are the dominant

suborders. Epiaqualfs and Epiaquerts are dominant in areas of

Pleistocene-age material on terraces, and Epiaquepts and

Udifluvents are dominant in areas of Holocene-age material.

The soils typically have a high proportion of montmorillonitic

clays and have a thermic soil temperature regime and an aquic

soil moisture regime.

About 97 percent of the land in this region is privately

owned. The native vegetation consists of deciduous bottomland forests. The diverse array of crops grown in the region

includes cotton, soybeans, milo, corn, rice (fig. O-2), sugarcane,

and wheat. The major management concerns on cropland

include flooding, excess water, and contamination of ground

water. 
of the United States 417

Figure 131A-1: Location of MLRA 131A in Land Resource Region O.

131A—Southern Mississippi River

Alluvium

This area (shown in fig. 131A-1) is in Louisiana (32 percent),

Arkansas (26 percent), Mississippi (26 percent), Missouri (12

percent), Tennessee (3 percent), and Kentucky (1 percent). A

small part of Illinois also is in the area. This MLRA makes up

about 29,555 square miles (76,585 square kilometers). It

includes the towns or cities of Lake Providence, Morgan City,

and Houma, Louisiana; Greenville, Yazoo City, and Clarksville,

Mississippi; Eudora, Helena, and West Memphis, Arkansas;

Caruthersville, Kennett, and Sikeston, Missouri; and the west

edge of Memphis, Tennessee. The cities of Baton Rouge and

New Orleans, Louisiana, are just outside this area. From north to

south, Interstates 57, 55, 40, 20, and 10 cross this area. The

Delta National Forest is in the part of this area in Mississippi.

Numerous national wildlife refuges and State parks are

throughout this area. Eaker Air Force Base and a small portion

of the St. Francis National Forest is in the part of the area in

Arkansas. This area is along a major flightpath for migratory

waterfowl.

Physiography

This area makes up most of the Mississippi Alluvial Plain

Section of the Coastal Plain Province of the Atlantic Plain. It is

on the alluvial plain along the lower Mississippi River, south of

its confluence with the Ohio River. The landforms in the area

are level or depressional to very gently undulating alluvial

plains, backswamps, oxbows, natural levees, and terraces. The

parts of the MLRA south of Baton Rouge, Louisiana, are on a

deltaic plain. Landform shapes range from convex on natural

levees and undulating terraces to concave in oxbows. These

shapes differentiate water-shedding positions from waterreceiving positions, both of which have a major role in soil

formation and hydrology. Average elevations start at sea level

in the southern part of the area and gradually rise to about 330

feet (100 meters) in the northwestern part. Maximum local relief

is about 15 feet (5 meters), but relief is considerably lower in

most of the area.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Lower Mississippi-St. Francis (0802), 30 percent; Lower

Mississippi-Yazoo (0803), 25 percent; Louisiana Coastal

(0808), 8 percent; Boeuf-Tensas (0805), 7 percent; Lower

Mississippi-Lake Maurepas (0807), 6 percent; Lower

Mississippi (0809), 6 percent; Upper White (1101), 6 percent;

Lower Red-Ouachita (0804), 5 percent; Lower MississippiHatchie (0801), 5 percent; and Lower Mississippi-Big Black

(0806), 2 percent. The lower Mississippi River and its

tributaries drain nearly all of the MLRA, but the Atchafalaya

River drains the extreme southwest part.

Geology

Bedrock in this area consists of Tertiary and Cretaceous

sands formed as beach deposits during the retreat of the

Cretaceous ocean from the midsection of the U.S. Alluvial

deposits from flooding and lateral migration of the Mississippi

River typically lie above the bedrock. These sediments are

sandy to clayey fluvial deposits of Quaternary age and are many

meters thick. The Yazoo, Tensas, and Atchafalaya Basins and

the modern deltaic plain are in areas of Holocene deposits. The

St. Francis Basin, in the northwestern part of the MLRA, and

some surfaces surrounded by the Yazoo Basin, in the central

part of the MLRA, are in areas of Wisconsin Stage deposits of

Pleistocene age. Some small areas in the western part of the

MLRA are covered by a thin mantle of pre-Wisconsin,

Quaternary-age loess deposits.
418 Major Land Resource Areas

Climate

The average annual precipitation in most of this area is 46 to

60 inches (1,170 to 1,525 millimeters). It can be as high as 65

inches (1,650 millimeters) in parts of the southern third of the

MLRA. Most of the rainfall occurs as frontal storms during late

fall, winter, and early spring, although an appreciable amount

of precipitation also occurs as convective thunderstorms during

the early part of the growing season. Hurricanes also can

produce high amounts of rainfall. The total amount of the

precipitation that occurs as snow ranges from less than 1

percent in the southern part of the MLRA to 28 percent in the

northern part. The average annual temperature ranges from 56

to 69 degrees F (14 to 21 degrees C), increasing from north to

south. The freeze-free period averages 285 days. It ranges from

210 days in the northern part of the area to 355 days in the

southern part.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 1.3%; ground water, 1.9%

Livestock—surface water, 1.3%; ground water, 2.4%

Irrigation—surface water, 7.7%; ground water, 51.4%

Other—surface water, 31.5%; ground water, 2.6%

The total withdrawals average 7,965 million gallons per day

(30,150 million liters per day). This is the sixth highest amount

of water among all of the MLRAs. About 58 percent is from

ground water sources, and 42 percent is from surface water

sources. In most years the supply of moisture is adequate for

maximum crop production. Surface water for public supply,

industrial use, and some irrigation is available in quantity from

the bayous, oxbow lakes, canals, and rivers throughout this

area. The dominant use of the surface water in the area is for

cooling thermoelectric power plants. Farms and small

communities use treated surface or ground water for most

purposes, except for irrigation. Numerous small, above-ground

water impoundments are used for raising commercial catfish

throughout the area. Most of the surface water is of good

quality and is suitable for most uses with some treatment. High

concentrations of suspended sediments, agricultural chemicals,

and municipal and industrial wastewater discharges contribute

to some local water-quality problems. Flooding is a major

concern in most of the area.

The principal sources of ground water in this area are sandy

and loamy materials in the Mississippi River alluvial deposits.

For example, 74 percent of all the ground water used in

Mississippi and almost all the irrigation water used in the “boot

heel” area of Missouri are pumped from alluvial aquifers.

Impermeable or very slowly permeable, smectitic clay layers

many meters thick overlie these aquifers in many parts of the

MLRA. Water moves through the clays via large desiccation

cracks that open during dry periods and swell closed during wet

periods. The ground water is used primarily for domestic

purposes and irrigation, but it also is used for public supply and

industry. It typically has levels of total dissolved solids that are

less than the national secondary drinking water standard of 500

parts per million (milligrams per liter). At the extreme southern

end of the area, in Louisiana, however, intrusion of seawater has

raised the level of total dissolved solids enough that this water

is not suitable for drinking or industrial use. Calcium,

manganese, sodium, sulfate, and bicarbonate are the major ions

in the ground water. Water in the river alluvium is generally

hard or very hard. The iron content is extremely high in

Arkansas but generally is not a significant problem in other

parts of the area. Where the ground water in the alluvial aquifer

is of poor quality, rural landowners obtain better quality

drinking water from Tertiary and Cretaceous sands below the

river alluvium.

Soils

The dominant soil orders in this MLRA are Alfisols,

Vertisols, Inceptisols, and Entisols. The soil temperature regime

is thermic in most of the MLRA. It is hyperthermic, however,

south of Baton Rouge, Louisiana. The soils in the MLRA

dominantly have an aquic soil moisture regime, smectitic clay

mineralogy, and mixed sand and silt fraction mineralogy. The

soils are very deep, dominantly poorly drained and somewhat

poorly drained, and dominantly loamy or clayey. Nearly level

Epiaquerts (Sharkey series), Vertic Epiaquepts (Tunica series),

and Vertic Endoaquepts (Dowling series) dominate the alluvial

flats and backswamps of Holocene to late Pleistocene age.

Nearly level to gently sloping Endoaquepts (Commerce series),

Udifluvents (Robinsonville series), and Fluvaquents (Convent

series) dominate the natural levees of Holocene age. Nearly

level to gently undulating, sandy Udifluvents (Bruno series) and

Udipsamments (Crevasse series) dominate the levee splays and

point bars of Holocene age. Nearly level to gently undulating

Endoaqualfs (Dundee series), Hapludalfs (Dubbs series), and

Epiaqualfs (Tensas series) dominate the terraces of Pleistocene

age.

Biological Resources

This area once consisted entirely of bottom-land hardwood

deciduous forests and mixed hardwood and cypress swamps.

The major tree species in the native plant communities in the

areas of bottom-land hardwoods formerly were and currently

are water oak, Nuttall oak, cherrybark oak, native pecan, red

maple, sweetgum, eastern cottonwood, and hickory. The major

tree species in the native plant communities in the swamps

formerly were and currently are cypress, water tupelo, water

oak, green ash, red maple, and black willow. The important

native understory species are palmetto, greenbrier, wild grape,
of the United States 419

and poison ivy in the areas of bottom-land hardwoods and

buttonbush, lizardtail, waterlily, water hyacinth, sedges, and

rushes in the swamps.

Some of the major wildlife species in this area are whitetailed deer, feral hogs, red fox, coyote, rabbit, gray squirrel,

American alligator, water turtles, water snakes, frogs, otters,

beavers, armadillo, crawfish, wild turkey, mourning doves,

ducks, and geese. Fishing is mainly in oxbow lakes, rivers, and

bayous. The species of fish in the area include largemouth bass,

smallmouth bass, catfish, drum, bluegill, gar, and yellow perch.

Crawdads are a commercial species in the southern end of this

MLRA.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 70%

Grassland—private, 2%

Forest—private, 15%; Federal, 3%

Urban development—private, 3%

Water—private, 6%

Other—private, 1%

Most of this area is in farms, which produce mainly cash

crops. Cotton, soybeans, milo, and corn are the main crops, and

sugarcane is a major crop in the southernmost part of the area.

Furrow irrigation is used in many areas during droughty parts of

the growing season. Rice is grown in some land-leveled, floodirrigated areas. Catfish and crawfish are produced commercially

on farm ponds that are contained by levees. The catfish are

produced throughout the MLRA, and the crawfish are produced

in the southern part of the area. Migratory waterfowl are

harvested throughout the area. Hardwood timber is harvested

on most forested wetlands, and most of the forested areas are

managed for wildlife.

About 29 percent of this MLRA is not protected from

flooding, and flooding occurs occasionally or frequently in

these unprotected areas. Levees protect nearly all of the

cropland, urban land, and grassland from flooding. Most areas

of forested wetlands are not protected from flooding. Networks

of drainage canals and ditches help to remove excess surface

water from the cropland.

The major resource concerns are control of surface water,

management of soil moisture, and maintenance of the content

of organic matter and productivity of the soils. Conservation

practices on cropland generally include nutrient management,

crop residue management, and alternative tillage systems,

especially no-till systems that reduce the cost of tillage. In

many areas land leveling or shaping optimizes the control of

surface water. Other major cropland management practices are

control of competing vegetation and insects through aerial or

ground spraying and fertility management programs that make

use of chemical fertilizers. 

Figure 131B-1: Location of MLRA 131B in Land Resource Region O.

131B—Arkansas River Alluvium

This area (shown in fig. 131B-1) is in Arkansas (67 percent)

and Louisiana (33 percent). It makes up about 3,955 square

miles (10,245 square kilometers). The towns of Montrose,

Dumas, and England, Arkansas, and Monroe, Louisiana, are in

this MLRA. Interstate 20 passes through Monroe, Louisiana.

Most parts of the Overflow National Wildlife Refuge, the Upper

Ouachita National Wildlife Refuge, and the D’Arbonne

National Wildlife Area are in this MLRA. The area is along a

major flightpath of migratory waterfowl.

Physiography

This area is in the Mississippi Alluvial Plain Section of the

Coastal Plain Province of the Atlantic Plain. It is on the alluvial
420 Major Land Resource Areas

plains along the lower Arkansas River in Arkansas and the

Ouachita River in Louisiana and Arkansas. The landforms in

the area are level or depressional to very gently undulating

alluvial plains, backswamps, oxbows, natural levees, and

terraces. Landform shapes range from convex on natural levees

and undulating terraces to concave in oxbows. Landform

shapes differentiate water-shedding positions from waterreceiving positions, both of which affect soil formation and

hydrology. Average elevations start at about 50 feet (15 meters)

in the southern part of the area and gradually rise to about 250

feet (75 meters) in the northwestern part. Maximum local relief

is about 10 feet (3 meters), but relief is considerably lower in

most of the area.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Boeuf-Tensas (0805), 48 percent; Lower Mississippi-St. Francis

(0802), 26 percent; Lower Red-Ouachita (0804), 20 percent;

and Lower Arkansas (1111), 6 percent. The lower reaches of the

Arkansas River, the Ouachita River, and the tributaries of both

these rivers drain the entire MLRA. A short reach of Bayou

Bartholomew, a National Wild and Scenic River, is in the

southern part of the area.

Geology

Bedrock in this area consists of Tertiary and Cretaceous

sands formed as beach deposits during the retreat of the

Cretaceous ocean from the midsection of the U.S. Alluvial

deposits from flooding and lateral migration of the Arkansas

and Ouachita Rivers typically lie above the bedrock. These

sediments are sandy to clayey fluvial deposits of Holocene to

late Pleistocene age and are many meters thick. The geologic

surfaces are identified as the Arkansas Lowlands, which extend

from the Yazoo Basin up the Arkansas River to the margin of

the Coastal Plain, and the parts of the Tensas Basin west of

Macon Ridge. The deposits on both of these surfaces are of

Holocene age. In some areas late Pleistocene terrace deposits

are within several meters of the present surfaces, but they do not

crop out in the MLRA.

Climate

The average annual precipitation ranges from 49 to 58

inches (1,245 to 1,475 millimeters), increasing from north to

south. Most of the rainfall occurs as frontal storms during late

fall, winter, and early spring, although an appreciable amount

of precipitation also occurs as convective thunderstorms during

the early part of the growing season. The total amount of the

precipitation that occurs as snow ranges from less than 1

percent in the southern part of the MLRA to 5 percent in the

northern part. The average annual temperature is 62 to 65

degrees F (16 to 18 degrees C). The freeze-free period averages

260 days and ranges from 250 to 275 days. It increases in

length from north to south.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 2.1%; ground water, 1.2%

Livestock—surface water, 0.8%; ground water, 0.5%

Irrigation—surface water, 10.8%; ground water, 50.9%

Other—surface water, 31.7%; ground water, 1.9%

The total withdrawals average 1,570 million gallons per day

(5,940 million liters per day). About 55 percent is from ground

water sources, and 45 percent is from surface water sources. In

most years the supply of moisture is adequate for maximum

crop production. Surface water for public supply, industrial use,

and some irrigation is available in quantity from bayous,

oxbow lakes, canals, and rivers throughout this area. The

dominant use of surface water in the area is for cooling

thermoelectric power plants. Numerous small, above-ground

water impoundments are used for raising commercial catfish

throughout the MLRA. Most of the surface water is of good

quality and is suitable for most uses with some treatment. High

concentrations of suspended sediments, agricultural chemicals,

and municipal and industrial wastewater discharges contribute

to some local water-quality problems. Flooding is a major

concern in most of the area.

The principal sources of ground water in this area are sandy

and loamy materials within the Arkansas and Mississippi River

alluvial deposits. The ground water is used primarily for

irrigation, but it also is used for public supply and industry. The

median level of total dissolved solids is 330 parts per million

(milligrams per liter), and the water is very hard. The iron

content is extremely high in the part of this area in Arkansas but

generally is not a significant problem in the part in Louisiana.

The level of total dissolved solids can reach 4,000 parts per

million (micrograms per liter) in the southeast corner of the part

of the area in Arkansas, making the water from the alluvial

aquifer unusable. The Sparta and Cockfield bedrock aquifers

are used in the northern tip of this area. The ground water in

these aquifers is lower in salts than the water in the alluvial

aquifer, and it is soft. The iron content generally is below the

national secondary standard for drinking water of 300 parts per

billion (micrograms per million). These aquifers provide

drinking water for rural landowners and small communities.

They also provide water for public supply in larger

communities and for industry. More and more irrigation wells

are being developed in the Sparta aquifer.
of the United States 421

Soils

The dominant soil orders in this MLRA are Vertisols,

Alfisols, Inceptisols, and Entisols. The soils in the area have a

thermic soil temperature regime. They dominantly have an

aquic soil moisture regime, smectitic clay mineralogy, and

mixed sand and silt fraction mineralogy. They are very deep

and generally are poorly drained to well drained and loamy or

clayey. Nearly level Epiaquerts (Perry series), Vertic Hapludolls

(Desha series), and Vertic Epiaquepts (Portland series) dominate

the Holocene-age alluvial flats and backswamps. Nearly level

to gently sloping Eutrudepts (Coushatta series), Udifluvents

(Roxana series), and Vertic Epiaquepts (Latanier series)

dominate the recent Holocene-age natural levees. Nearly level

to gently undulating, sandy Udifluvents (Bruno series) and

Udipsamments (Crevasse series) dominate the recent Holoceneage levee splays and point bars. Nearly level to gently

undulating Epiaqualfs (Hebert series), Hapludalfs (Rilla and

Sterlington series), and Argiudolls (Caspiana series) dominate

the Holocene-age natural levees along the older meander scars.

Biological Resources

This area once consisted entirely of bottom-land hardwood

deciduous forest and mixed hardwood and cypress swamps. The

major tree species in the native plant communities in the areas

of bottom-land hardwoods formerly were and currently are

water oak, Nuttall oak, cherrybark oak, native pecan, red maple,

sweetgum, eastern cottonwood, and hickory. The major tree

species in the native plant communities in the swamps formerly

were and currently are cypress, water tupelo, water oak, green

ash, red maple, and black willow. The important native

understory species are palmetto, greenbrier, wild grape, and

poison ivy in the areas of bottom-land hardwoods and

buttonbush, lizardtail, waterlily, water hyacinth, sedges, and

rushes in the swamps.

Some of the major wildlife species in this area are whitetailed deer, feral hogs, red fox, coyote, rabbit, gray squirrel,

American alligator, water turtles, water snakes, frogs, otters,

beavers, armadillo, crawfish, wild turkey, mourning doves,

ducks, and geese. Fishing is mainly in oxbow lakes, rivers, and

bayous. The species of fish in the area include largemouth bass,

smallmouth bass, catfish, drum, bluegill, gar, and yellow perch.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 70%

Grassland—private, 2%

Forest—private, 22%; Federal, 1%

Urban development—private, 1%

Water—private, 3%

Other—private, 1%

Farms and scattered tracts of forested wetlands make up

nearly all of this area. The farms produce mainly cash crops.

Cotton, soybeans, milo, and corn are the main crops. In many

areas furrow irrigation is used during droughty parts of the

growing season. Throughout the area, catfish are produced

commercially on farm ponds that are contained by levees.

Migratory waterfowl are harvested throughout the area.

Hardwood timber is harvested on some forested wetlands, and

most forested areas are managed for wildlife.

About 15 percent of this MLRA is not protected from

flooding, and flooding occurs occasionally or frequently in

these unprotected areas. Levees protect nearly all of the

cropland from flooding. Most of the forested wetlands are not

protected from flooding. Networks of drainage canals and

ditches help to remove excess surface water from the cropland.

The major resource concerns are control of surface water,

management of soil moisture, and maintenance of the content

of organic matter and productivity of the soils. Conservation

practices on cropland generally include nutrient management,

crop residue management, and alternative tillage systems,

especially no-till systems. In many areas land leveling or

shaping optimizes the control of surface water. Other major

cropland management practices are control of competing

vegetation and insects through aerial or ground spraying of

herbicides and insecticides and fertility management programs

that make use of chemical fertilizers. 

131C—Red River Alluvium

This area (shown in fig. 131C-1) is in Louisiana (86 percent)

and Arkansas (14 percent). It makes up about 2,410 square

miles (6,245 square kilometers). The eastern half of the city of

Shreveport and the towns of Alexandria and Bossier City,

Louisiana, are in this MLRA. Interstate 20 crosses this area and

intersects Interstate 49 in Shreveport. Interstate 30 crosses the

northern tip of the area, in Arkansas. Small areas of the

Kisatchie National Forest are along the southwest edge of this

MLRA. The England and Barksdale Air Force Bases are in this

area. The area is along a major flightpath of migratory

waterfowl.

Physiography

Almost all of this area is in the West Gulf Coastal Plain

Section of the Coastal Plain Province of the Atlantic Plain. The

southern end is in the Mississippi Alluvial Plain Section of the

same province and division. This MLRA is on the alluvial

plain along the lower Red River in Arkansas and Louisiana.

The landforms in the area are level or depressional to very

gently undulating alluvial plains, backswamps, oxbows,

natural levees, and terraces. Landform shapes range from
422 Major Land Resource Areas

Figure 131C-1: Location of MLRA 131C in Land Resource Region O.

convex on natural levees and undulating terraces to concave in

oxbows. Landform shapes differentiate water-shedding

positions from water-receiving positions, both of which have a

major effect on soil formation and hydrology. Average

elevations start at about 40 feet (12 meters) in the southern part

of the area and gradually rise to about 270 feet (80 meters) in

the northwestern part. Maximum local relief is about 10 feet (3

meters), but relief is considerably lower in most of the area.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows: RedSulphur (1114), 63 percent; Louisiana Coastal (0808), 35

percent; and Lower Red-Ouachita (0804), 2 percent. The lower

Red River and its tributaries drain the MLRA to its confluence

with the Atchafalaya and Mississippi Rivers, which occurs in

MLRA 131A.

Geology

Bedrock in this area consists of Tertiary and Cretaceous

sands formed as beach deposits during the retreat of the

Cretaceous ocean from the midsection of the U.S. Alluvial

deposits from flooding and lateral migration of the Red River

typically lie above the bedrock. These sediments are sandy to

clayey fluvial deposits of Holocene to late Pleistocene age and

are many meters thick. In some areas late Pleistocene terrace

deposits are within several meters of the present surfaces, but

they do not crop out in this MLRA. The geologic history of the

area is greatly influenced by a large logjam that formed in the

Red River channel in the middle part of the area during the late

18th century and the early 19th century. At the time of its largest

extent, the logjam obstructed the river and its tributary outlets

for a distance of 160 miles downstream from the Arkansas State

boundary. Backwater flooding, reformation of natural levees,

and crevasse splays caused by this logjam played a major role

in covering large parts of the area with a mantle of recent clayey

to sandy material. Destruction of the logjam in the late 1800s

resulted in the drainage of many large lakes that had formed.

Climate

The average annual precipitation in this area ranges from 47

to 62 inches (1,195 to 1,575 millimeters), increasing from north

to south. Most of the rainfall occurs as frontal storms during

late fall, winter, and early spring, although an appreciable

amount of precipitation also occurs as convective thunderstorms

during the early part of the growing season. The total amount of

the precipitation that occurs as snow ranges from less than 1

percent in the southern part of the area to 5 percent in the

northern part. The average annual temperature ranges from 63

to 67 degrees F (17 to 19 degrees C). The freeze-free period

averages 280 days. It ranges from 255 days in the northern part

of the area to 305 days in the southern part.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 3.1%; ground water, 3.3%

Livestock—surface water, 1.4%; ground water, 1.1%

Irrigation—surface water, 1.3%; ground water, 8.1%

Other—surface water, 77.3%; ground water, 4.4%

The total withdrawals average 840 million gallons per day

(3,180 million liters per day). About 17 percent is from ground

water sources, and 83 percent is from surface water sources. In

most years the supply of moisture is adequate for maximum

crop production. Surface water for public supply, industrial use,

and some irrigation is available in quantity from bayous,
of the United States 423

oxbow lakes, canals, and rivers throughout the area. The

dominant use of surface water in the area is for cooling

thermoelectric power plants. Numerous small, above-ground

water impoundments are used for raising commercial catfish

throughout the MLRA. Most of the surface water is of good

quality and is suitable for most uses with some treatment. High

concentrations of suspended sediments, agricultural chemicals,

and municipal and industrial wastewater discharges contribute

to some local water-quality problems. Flooding is a major

concern in most of the area.

The principal sources of ground water in this area are sandy

and loamy materials within the Red River alluvial deposits.

Impermeable or very slowly permeable smectitic clays overlie

these aquifers in many parts of the MLRA, and these clay layers

are many meters thick in some areas. Water moves through the

smectitic clays via large desiccation cracks that open during dry

periods and swell closed and form slickensides during wet

periods. The ground water is used primarily for irrigation, but it

also is used for public supply and industry. The median level of

total dissolved solids is 330 parts per million (milligrams per

liter), and the water is very hard. The iron content is generally

high in the part of this area in Arkansas, but it generally is not a

significant problem in the part in Louisiana. The level of total

dissolved solids can reach 4,000 parts per million (micrograms

per liter) in the southwest corner of the part of the area in

Arkansas, making the water from the alluvial aquifer unusable.

The Sparta and Cockfield bedrock aquifers are used in the

northern end of this area, in Arkansas. The ground water in

these aquifers has a lower mineral content than the water in the

alluvial aquifer, and it is soft. The iron content generally is

below the national secondary standard for drinking water of 300

parts per billion (micrograms per million). These aquifers

provide drinking water for rural landowners and small

communities. They also provide water for public water supply

in the larger communities. More and more irrigation wells are

being developed in the Sparta aquifer.

Soils

The dominant soil orders in this MLRA are Vertisols,

Entisols, Inceptisols, and Alfisols. The soils in the area have a

thermic soil temperature regime. They dominantly have an

aquic soil moisture regime, smectitic clay mineralogy, and

mixed sand and silt fraction mineralogy. They are very deep

and generally are poorly drained to moderately well drained and

loamy or clayey. Nearly level Epiaquerts (Moreland series) and

Vertic Endoaquepts (Yorktown series) dominate the Holoceneage alluvial flats and backswamps. Nearly level to gently

sloping Endoaquepts (Coushatta series), Udifluvents (Severn

and Roxana series), and Vertic Epiaquepts (Latanier series)

dominate the Holocene-age natural levees. Nearly level to

gently undulating, coarse-silty over clayey Udifluvents (Caplis

series) and sandy Udifluvents (Kiomatia series) dominate the

Holocene-age levee splays and point bars. Nearly level to

gently undulating Hapludalfs (Gallion and Rilla series) and

Argiudolls (Caspiana series) dominate the Holocene-age

natural levees along the older meander scars.

Biological Resources

This area once consisted entirely of bottom-land hardwood

deciduous forest and mixed hardwood and cypress swamps. The

major tree species in the native plant communities in the areas

of bottom-land hardwoods formerly were and currently are

water oak, Nuttall oak, cherrybark oak, native pecan, red maple,

sweetgum, eastern cottonwood, and hickory. The major tree

species in the native plant communities in the swamps formerly

were and currently are cypress, water tupelo, water oak, green

ash, red maple, and black willow. The important native

understory species are palmetto, greenbrier, wild grape, and

poison ivy in the areas of bottom-land hardwoods and

buttonbush, lizardtail, waterlily, water hyacinth, sedges, and

rushes in the swamps.

Some of the major wildlife species in this area are whitetailed deer, feral hogs, red fox, coyote, rabbit, gray squirrel,

American alligator, water turtles, water snakes, frogs, otters,

beavers, armadillo, crawfish, wild turkey, mourning doves,

ducks, and geese. Fishing is mainly in oxbow lakes, rivers, and

bayous. The species of fish in the area include largemouth

bass, smallmouth bass, catfish, drum, bluegill, gar, and yellow

perch.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 37%

Grassland—private, 20%

Forest—private, 30%; Federal, 1%

Urban development—private, 5%

Water—private, 5%

Other—private, 2%

Farms and scattered tracts of forested wetlands make up

nearly all of this area. The farms produce mainly cash crops.

Cotton, soybeans, milo, and corn are the main crops. Sugarcane

is a major crop in the southernmost part of the area. In many

areas furrow irrigation is used during droughty parts of the

growing season. Throughout the area, catfish are produced

commercially on farm ponds that are contained by levees.

Migratory waterfowl are harvested throughout the area.

Hardwood timber is harvested on some forested wetlands, and

most forested areas are managed for wildlife.

About 22 percent of this MLRA is not protected from

flooding, and flooding occurs occasionally or frequently.

Levees protect nearly all of the cropland from flooding. Most of

the forested wetlands are not protected from flooding. Networks
424 Major Land Resource Areas

Figure 131D-1: Location of MLRA 131D in Land Resource Region O.

of drainage canals and ditches help to remove excess surface

water from the cropland.

The major resource concerns are control of surface water,

management of soil moisture, and maintenance of the content

of organic matter and productivity of the soils. Conservation

practices on cropland generally include nutrient management,

crop residue management, and alternative tillage systems,

especially no-till systems. In many areas land leveling or

shaping optimizes the control of surface water. Other major

cropland management practices are control of competing

vegetation and insects through aerial or ground spraying of

herbicides and insecticides and fertility management programs

that make use of chemical fertilizers. 

131D—Southern Mississippi River

Terraces

This area (shown in fig. 131D-1) is in Arkansas (88 percent)

and Louisiana (12 percent). It is in two separate areas that

together make up about 2,945 square miles (7,635 square

kilometers). The towns of Lonoke and Stuttgart, Arkansas, are

in the northeastern part of the MLRA, which is called the Grand

Prairie. Bastrop, Louisiana, is in the southwestern part of the

MLRA. Interstate 40 crosses the northern tip of the Grand

Prairie area. The Bayou Meto Wildlife Preserve and the White

River and Overflow National Wildlife Refuges are in this

MLRA. The MLRA is along a major flightpath of migratory

waterfowl.

Physiography

This MLRA is in the Mississippi Alluvial Plain Section of

the Coastal Plain Province of the Atlantic Plain. It consists

dominantly of Pleistocene-age, level to gently sloping terraces

along the Mississippi River. Slopes generally range from level

to gently sloping but are steep along terrace escarpments.

Channel scars are evident in some areas. Elevation is generally

50 to 250 feet (15 to 75 meters) on the terraces.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Lower Mississippi-St. Francis (0802), 56 percent; Lower RedOuachita (0804), 41 percent; and Boeuf-Tensas (805), 3

percent. Bayou Bartholomew and LaGrue Bayou are major

tributaries in this area. La Grue Bayou drains the Grand Prairie

area. Bayou Bartholomew, in the southwestern part of the

MLRA, has been designated a National Wild and Scenic River.

Geology

Bedrock in this area consists of Tertiary and Cretaceous

sands formed as beach deposits during the retreat of the

Cretaceous ocean from the midsection of the U.S. Alluvial

deposits from flooding and lateral migration of the rivers

crossing this area typically lie above the bedrock. These

sediments form Pleistocene-age alluvial terraces. Silty alluvium

underlies most of the area. Clayey sediments are in old channel

scars. The Pleistocene terraces are part of the Prairie Terrace

complex. A minor portion of the area is in the Deweyville and

Montgomery terrace formation. These terraces have a base of

red alluvium capped by one to several meters of brownish

alluvium.

Climate

The average annual precipitation in thia area is 49 to 56

inches (1,245 to 1,420 millimeters), increasing from north to

south. Most of the rainfall occurs as frontal storms in spring and

early summer. Some high-intensity, convective thunderstorms
of the United States 425

occur in summer. The average seasonal snowfall is 5 inches (12

centimeters). The average annual temperature is 61 to 65

degrees F (16 to 18 degrees C), increasing from north to south.

The freeze-free period averages 255 days. It ranges from 245

days in the northern part of the area to 270 days in the southern

part.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 1.4%; ground water, 1.2%

Livestock—surface water, 0.9%; ground water, 1.4%

Irrigation—surface water, 11.5%; ground water, 67.4%

Other—surface water, 15.0%; ground water, 1.1%

The total withdrawals average 750 million gallons per day

(2,840 million liters per day). About 71 percent is from ground

water sources, and 29 percent is from surface water sources. In

most years the supply of moisture is not adequate for maximum

crop production because of the distribution of rainfall during

the growing season. Some surface water for industrial use and

some limited irrigation is available from bayous, canals, and

rivers throughout the area. Most of the surface water is of good

quality and is suitable for most uses with some treatment. Some

farms and small communities depend on treated surface water.

High concentrations of suspended sediments, agricultural

chemicals, and municipal and industrial wastewater discharges

contribute to some local water-quality problems.

The principal sources of ground water in this area are sandy

and silty materials within the alluvial terraces and the Cockfield

and Sparta bedrock aquifers. The Sparta aquifer is a sole-source

aquifer for most of the communities in the area. The ground

water is used primarily for irrigation, but it is also used for

domestic purposes and for public supply and industry. The

median level of total dissolved solids in the alluvial aquifer is

330 parts per million (milligrams per liter), and the water in this

aquifer is very hard. The iron content is generally high in the

part of this MLRA in Arkansas, but it generally is not a

significant problem in the part in Louisiana. The water in the

Sparta and Cockfield bedrock aquifers typically has a lower

content of salts than the water in the alluvial aquifer, and it is

soft. The content of iron generally is below the national

secondary standard for drinking water of 300 parts per billion

(micrograms per million). These aquifers provide drinking

water for rural landowners and small communities. They also

provide water for public supply in the larger communities.

More and more irrigation wells are being developed in the

Sparta aquifer.

The aquifers in this area are recharged by the Arkansas and

White Rivers. Pumping has exceeded the amount of recharge,

so water levels have been dropping almost 1 foot per year. The

historical decline in the elevation of the water table has

prompted a major federally funded water resources project to be

undertaken in the Grand Prairie part of this area. The focus of

the project is on improving irrigation water management. The

U.S. Army Corps of Engineers, in cooperation with the Natural

Resources Conservation Service, other Federal agencies, and

State agencies, is assisting farmers in the construction of canals,

pipelines, and on-farm reservoirs for irrigation tailwater

reclamation and reuse.

Soils

The dominant soils in this MLRA are Alfisols. They have a

thermic soil temperature regime, an ustic or aquic soil moisture

regime, and mixed mineralogy. They are very deep and formed

dominantly in silty alluvium. They generally are moderately

well drained to poorly drained. Gently sloping Hapludalfs

(Goodwill series) are on natural levees and low terraces. Gently

sloping to level Hapludalfs (Immanuel and Stuttgart series) and

Fraglossudalfs (Grenada series) are on broad interfluves and

along terrace escarpments. Level Endoaqualfs (Idee series),

Albaqualfs (Dewitt series), Glossaqualfs (Ethel series),

Epiaqualfs (Lagrue), and Fragiaqualfs (Henry series) are on low

terraces and natural levees. Nearly level and level Endoaqualfs

(Tichnor and Forestdale series) are on low terraces, natural

levees, and flood plains. Nearly level Dystrudepts (Oaklimeter

series) are along drainageways and on flood plains.

Biological Resources

This area supports hardwoods and pines. The Grand Prairie

area, in Arkansas, originally supported tall prairie grasses

interlaced with hardwood timber. Cherrybark and Shumard oak

are widely distributed. Yellow-poplar, white ash, cottonwood,

and black walnut are important species on the flood plains.

Loblolly pine and shortleaf pine are on a wide variety of sites,

mainly the eroded soils on uplands and ridges. Other hardwood

species that commonly grow in this area are white oak,

basswood, sweetgum, water oak, American elm, blackgum,

sycamore, sassafras, southern red oak, chinkapin oak, American

beech, and hickory.

Some of the major wildlife species in this area are whitetailed deer, coyote, bobcat, beaver, raccoon, skunk, armadillo,

mink, cottontail, turkey, mourning dove, ducks, and geese. The

species of fish in the area include channel catfish, largemouth

black bass, crappie, and bluegill.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 42%

Grassland—private, 4%

Forest—private, 46%; Federal, 1%

Urban development—private, 3%

Water—private, 3%

Other—private, 1%
426

Scattered tracts of forests and farms make up nearly all of

this area. Rice, soybeans, and wheat are the main crops. In most

areas furrow or flood irrigation is used throughout the growing

season. Hardwood timber is harvested on some forested

wetlands, and most forested areas are managed for wildlife.

Bait fish are produced commercially in ponds that are

contained by levees. Migratory waterfowl are harvested

throughout the area.

The major soil resource concerns are management of soil

moisture, erosion control, and maintenance of the content of

organic matter and productivity of the soils. Depletion of

ground water through excessive pumping is a major concern in

the Grand Prairie area.

Conservation practices on cropland generally include

nutrient management, crop residue management, and alternative

tillage systems, especially no-till systems that reduce the need

for tillage. In many areas land leveling or shaping optimizes the

control of surface water. Other major cropland management

practices are control of competing vegetation and insects

through aerial or ground spraying of herbicides and insecticides

and fertility management programs that make use of chemical

fertilizers. 
427

Figure P-1: Location of Land Resource Region P.

P—South Atlantic and Gulf Slope Cash

Crops, Forest, and Livestock Region

This region (shown in fig. P-1) is in Georgia (16 percent),

Mississippi (15 percent), Alabama (14 percent), North

Carolina (11 percent), Texas (8 percent), Louisiana (7 percent),

South Carolina (7 percent), Virginia (7 percent), Arkansas

(5 percent), Florida (4 percent), Tennessee (4 percent),

Kentucky (1 percent), and Oklahoma (1 percent). Also, very

small parts of the region are in Illinois and Missouri. The

region makes up 264,095 square miles (684,340 square

kilometers).

This region consists of generally smooth Atlantic and Gulf

Coast marine terraces and the hilly piedmont area (fig. P-2).

Elevation ranges from 80 to 655 feet (25 to 200 meters) on the

coastal plain and from 330 to 1,310 feet (100 to 400 meters) in

the piedmont. Local relief typically ranges from 10 to 100 feet

(3 to 30 meters) on the coastal plain and from 20 to 200 feet (6

to 60 meters) in the piedmont. The geologic material consists of

very thick deposits of sandy to clayey marine sediments on the

coastal plain and Precambrian and Paleozoic metamorphic and

igneous rocks in the piedmont.

Abundant moisture and a long growing season favor

agricultural production in this region. If crops are to be grown,

artificial drainage typically is needed to lower the water table

on the lower marine terraces. The climate is hot and humid. It is

characterized by long, hot summers and short, mild winters. The

mean annual precipitation is 44 to 63 inches (1,120 to 1,600

millimeters). The precipitation falls almost entirely as rainfall

during frontal storms in late fall, winter, and early spring; as

rainfall occurring as convective storms during the growing

season; and as heavy rainfall produced by tropical storms.

Typically, snowfall is light in the northern part of the region

and does not occur in the southern part. The mean annual air

temperature in most of the region is 59 to 66 degrees F (15 to

19 degrees C). The freeze-free period ranges from 225 to 290

days. The mean annual air temperature and the length of the

freeze-free period increase from north to south.

The total withdrawals of freshwater in this region average

about 30,370 million gallons per day (118,140 million liters

per day). This region is one of six major land resource regions
428 Major Land Resource Areas

Figure P-2: An area of Land Resource Region P.

in which more than 30,000 million gallons per day (113,550

million liters per day) is used. About 81 percent is from surface

water sources, and 19 percent is from ground water sources.

About 78 percent of the water is used for cooling thermoelectric

power plants and for mining and industry, and 12 percent is

used for public supplies.

The soils in this region are dominantly Alfisols, Entisols,

Inceptisols, Ultisols, or Vertisols. They typically have a thermic

soil temperature regime and a udic soil moisture regime.

Hapludults, Kandiudults, Hapludalfs, and Paleudults formed in

marine sediments on the coastal plain. Hapludalfs,

Fraglossudalfs, and Fragiudalfs formed in thick deposits of

loess east of the Mississippi River. Dystruderts, Hapluderts, and

Paleudalfs formed in clayey deposits in the central part of the

region. Eutrudepts and Hapludalfs formed on the ridgetops and

Hapluderts on the bottom land in the northwest corner of the

region. Hapludalfs, Hapludults, and Kanhapludults formed in

material weathered from the crystalline rocks in the piedmont.

Dystrudepts and Fluvaquents formed in alluvium on flood

plains. Paleudults, Hapludalfs, and Quartzipsamments are in the

southeast corner of the region.

About 97 percent of the land in this region is privately

owned. The native vegetation consists of oak-pine forests. The

diverse array of crops includes cotton, soybeans, peanuts, corn,

rice, sugarcane, and wheat. The major management concerns on

cropland include maintenance of the productivity of the soils,

control of erosion, and prevention of ground-water

contamination. 
of the United States 429

Figure 133A-1: Location of MLRA 133A in Land Resource Region P.

133A—Southern Coastal Plain

This area (shown in fig. 133A-1) is in Alabama (26 percent),

Mississippi (24 percent), Georgia (21 percent), Florida

(8 percent), North Carolina (7 percent), Virginia (5 percent),

South Carolina (4 percent), Tennessee (4 percent), and

Louisiana (1 percent). It makes up about 106,485 square miles

(275,930 square kilometers). It is the largest MLRA in the U.S.

The city of Alexandria, Virginia, is at the northernmost tip of

the area. The MLRA also includes Fredericksburg, Richmond,

and Petersburg, Virginia; Rocky Mount, Goldsboro,

Fayetteville, and Lumberton, North Carolina; Florence, Sumter,

and Orangeburg, South Carolina; Albany and Tifton, Georgia;

Tallahassee, Florida; Tuskegee, Eufaula, Selma, and Tuscaloosa,

Alabama; Savannah, Tennessee; Corinth, Starkville, Grenada,

Meridian, Hattiesburg, and McComb, Mississippi; and

Bogalusa, Louisiana. Interstates 95, 64, 85, 40, 20, 20/59,

26, 16, 75, 10, 65, 59, and 55 cross this area from north to

south.

Forts Belvoir and A.P. Hill, Cameron Station Military

Reservation, and Quantico Marine Corps Combat Development

Command are in the part of this area in Virginia. The MLRA

also includes Fort Bragg and Pope Air Force Base near

Fayetteville, North Carolina; a small part of Fort Gordon and

Fort Stewart in Georgia; Maxwell Air Force Base and Fort

Rucker in Alabama; Whiting Naval Air Station and Eglin Air

Force Base in Florida; the National Aeronautics and Space

Administration’s National Space Technology Center in

Mississippi; and the western edge of the Department of

Energy’s nuclear materials production facility at the Savannah

River Site in South Carolina.

Mt. Vernon, George Washington’s Birthplace National

Monument, and Robert E. Lee’s birthplace are in the part of this

MLRA in Virginia. A number of national wildlife refuges, State

forests, and State parks are throughout this area. A number of

national forests and National Wild and Scenic Rivers are in the

southern part of the area. The Choctaw Indian Reservation is in

the part of the area in Mississippi.

Physiography

This area extends from Virginia to Louisiana and

Mississippi, but it is almost entirely within three sections of the

Coastal Plain Province of the Atlantic Plain. The northern part

is in the Embayed Section, the middle part is in the Sea Island

Section, and the southern part is in the East Gulf Coastal Plain

Section. This MLRA is strongly dissected into nearly level and

gently undulating valleys and gently sloping to steep uplands.

Stream valleys generally are narrow in their upper reaches but

become broad and have widely meandering stream channels as

they approach the coast. Elevation ranges from 80 to 655 feet

(25 to 200 meters), increasing gradually from the lower Coastal

Plain northward. Local relief is mainly 10 to 20 feet (3 to 6

meters), but it is 80 to 165 feet (25 to 50 meters) in some of the

more deeply dissected areas.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Mobile-Tombigbee (0316), 12 percent; ChoctawhatcheeEscambia (0314), 12 percent; Apalachicola (0313), 10 percent;

Pascagoula (0317), 9 percent; Altamaha-St. Marys (0307), 7

percent; Alabama (0315), 6 percent; Pearl (0318), 6 percent;

Suwannee (0311), 4 percent; Ogeechee-Savannah (0306), 4

percent; Pee Dee (0304), 4 percent; Lower Mississippi-Yazoo

(0803), 4 percent; Lower Chesapeake (0208), 3 percent; Cape

Fear (0303), 3 percent; Ochlockonee (0312), 2 percent; NeusePamlico (0302), 2 percent; Lower Mississippi-Hatchie (0801), 2

percent; Lower Tennessee (0604), 2 percent; Chowan-Roanoke

(0301), 2 percent; Edisto-Santee (0305), 2 percent; Middle

Tennessee-Elk (0603), 1 percent; Lower Mississippi-Lake

Maurepas (0807), 1 percent; Lower Mississippi-Big Black

(0806), 1 percent; and Potomac (0207), 1 percent. This MLRA

stretches from the Chesapeake Bay in the north to just short of

the Mississippi River in Louisiana and Mississippi. A great

number of major rivers originating in the Appalachian

Mountains west of this area cross the MLRA and empty into the

Atlantic Ocean or the Gulf of Mexico.

Geology

This MLRA is bordered on the west and north by the “fall

line.” This line of water falls marks the western and northern

extent of the unconsolidated Coastal Plain sediments. It is an

erosional scarp formed when this area was the Atlantic Ocean

shore in Mesozoic time. The MLRA is underlain by eroded

igneous and metamorphic bedrock. Rivers and streams draining

the Appalachians deposited a thick wedge of silt, sand, and

gravel east and south of the fall line as delta deposits in the

Atlantic Ocean. These Jurassic and Cretaceous river sediments
430 Major Land Resource Areas

were eventually exposed as the Coastal Plain uplifted and the

sea level changed. When the sea level rose again, the Coastal

Plain was submerged and covered by a thin layer of Cretaceous

sands in the eastern half of the area. In the western part of the

area, the water was deeper and limestone, dolomite, and

calcareous sands were deposited. As the Coastal Plain

continued to uplift and the sea level dropped again, Quaternary

material consisting of unconsolidated clay, silt, sand, and

gravel was deposited over the Tertiary sand and carbonates.

Subsequent changes in the sea level created terraces in these

younger deposits along many of the streams and rivers draining

this area. Much of the MLRA has a “benched” appearance

because of the cycles of erosion and deposition that occurred as

the area was exposed and submerged numerous times in its

geologic history.

Climate

The average annual precipitation in most of this area is 41 to

60 inches (1,040 to 1,525 millimeters), increasing from north to

south. It is typically 61 to 72 inches (1,550 to 1,830

millimeters) in the extreme southwest part of the area, inland

along the Gulf Coast. The minimum precipitation occurs in

autumn throughout the area. The maximum precipitation

occurs during midsummer in the eastern part of the area and

during winter and spring in the western part. Rainfall typically

occurs as high-intensity, convective thunderstorms during the

summer, but moderate-intensity tropical storms can produce

large amounts of rainfall during winter in the eastern and

southwestern parts of the area. Snowfall does not occur in the

southern part of the area, and it occasionally occurs in the

northern part. The average annual temperature is 55 to 68

degrees F (13 to 20 degrees C), increasing from north to south.

The freeze-free period averages 250 days and ranges from 200

to 305 days, increasing in length from north to south.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 6.1%; ground water, 5.1%

Livestock—surface water, 1.9%; ground water, 4.4%

Irrigation—surface water, 3.9%; ground water, 4.5%

Other—surface water, 69.7%; ground water, 4.4%

The total withdrawals average 7,030 million gallons per day

(26,610 million liters per day). This MLRA is among the top 10

MLRAs in total amount of water used. About 18 percent is from

ground water sources, and 82 percent is from surface water

sources. Precipitation and perennial streams provide an

abundance of water. Water for livestock is primarily obtained

from perennial streams and small farm ponds. The many

perennial streams have the potential for supplying water for

municipal use, human consumption, and farming but have been

little used for these purposes. A few large reservoirs are

available for recreation and other uses. Most of the surface

water in this area is used for cooling thermoelectric power

plants. The surface water is suitable for all uses.

Domestic water supplies in this area are obtained mainly

from shallow wells. In most areas one or more aquifers provide

ample ground water for irrigation and for municipal and

industrial uses. The Floridan aquifer (limestone, dolomite, and

calcareous sand) is heavily used in the southern part of the area,

and the Cretaceous sand aquifer is extensively used throughout

the area. Both of these aquifers have some of the best quality

water in the area. The level of total dissolved solids generally is

less than 250 parts per million (milligrams per liter), and the

water is typically soft or moderately hard. A number of more

minor aquifers are used for ground water throughout the area.

Mississippi, for example, obtains water from 12 of the 14

principal aquifers in that State. Since the ground water is

shallow throughout the area, nitrate contamination from

barnyards, confined animal-feeding operations, septic systems,

and poor nutrient management practices is always a potential

problem. Some ground water in Mississippi has naturally high

levels of iron, and many wells in South Carolina pump water

that exceeds the national drinking water standard for sodium.

Brine water is commonly encountered in wells in the part of this

area in Louisiana. The brine originates from salt domes and

moves up to the shallow aquifers along faults created by the

upward migration of the domes.

Soils

The dominant soil orders in this MLRA are Ultisols,

Entisols, and Inceptisols. The soils in the area dominantly have

a thermic soil temperature regime, a udic or aquic soil moisture

regime, and siliceous or kaolinitic mineralogy. They generally

are very deep, somewhat excessively drained to poorly drained,

and loamy. Hapludults formed in marine sediments (Luverne

and Sweatman series) and mixed marine sediments and

alluvium (Smithdale series) on hills and ridges. Kandiudults

formed in marine sediments (Dothan, Fuquay, Norfolk, and

Orangeburg series) and mixed marine and fluvial sediments

(Troup series) on hills and ridges. Fragiudults (Ora and

Savannah series) and Paleudults (Ruston series) formed in

mixed marine and fluvial sediments on uplands and stream

terraces. Fluvaquents (Bibb series) and Endoaquepts

(Mantachie series) formed in alluvium on flood plains.

Quartzipsamments (Lakeland series) formed in sandy eolian or

marine material on uplands. Paleaquults (Rains series) formed

in marine and fluvial sediments on terraces.

Biological Resources

This area supports mixed oak-pine vegetation. Loblolly

pine, longleaf pine, slash pine, shortleaf pine, sweetgum,

yellow-poplar, red oak, and white oak are the major overstory
of the United States 431

species. Dogwood, gallberry, and farkleberry are the major

understory species. Common sweetleaf, American holly,

greenbrier, southern bayberry, little bluestem, Elliott bluestem,

threeawn, grassleaf goldaster, native lespedezas, and low

panicums are other understory species.

Some of the major wildlife species in this area are whitetailed deer, turkey, rabbit, squirrel, bobwhite quail, and

mourning dove. The species of fish in the area include bass,

bluegill, and channel catfish.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 17%

Grassland—private, 8%

Forest—private, 61%; Federal, 3%

Urban development—private, 6%

Water—private, 3%

Other—private, 2%

Timber production, cash-grain crops, and forage production

are important in this MLRA. Soybeans, cotton, corn, and wheat

are the major crops grown throughout the area. Pastures are

grazed mainly by beef cattle, but some dairy cattle and hogs are

raised in the area.

The major resource concerns are water erosion, maintenance

of the content of organic matter and productivity of the soils,

control of surface water, artificial drainage, and management of

surface compaction and soil moisture. Conservation practices

on cropland generally include systems of crop residue

management, cover crops, crop rotations, water disposal,

subsoiling or deep tillage, pest management, and nutrient

management. The most important conservation practice in

pastured areas is prescribed grazing. Pastures commonly are

overseeded with small grains and/or legumes to supplement

forage production during winter. Haying also helps to provide

supplemental feed during the long winters. Critically eroding

areas and areas where animals congregate should be monitored

and treated. 

Figure 133B-1: Location of MLRA 133B in Land Resource Region P.

133B—Western Coastal Plain

This area (shown in fig. 133B-1) is in Texas (47 percent),

Louisiana (31 percent), Arkansas (21 percent), and Oklahoma

(1 percent). It makes up about 45,450 square miles (117,770

square kilometers). The towns of Longview, Lufkin, Marshall,

Nacogdoches, and Tyler, Texas, are in the southwestern part of

the area. The towns of Minden, Ruston, and West Monroe,

Louisiana, are in the southern part. The towns of Magnolia,

Hope, Camden, El Dorado, and Pine Bluff, Arkansas, are in the

northern part. Shreveport, Louisiana, and Little Rock, Arkansas,

are major cities in this MLRA. Interstate 30 crosses the

northernmost part of this area, in Texas and Arkansas, and

Interstate 20 crosses the central part, in Texas and Louisiana.

Interstate 49 runs from Shreveport south through Louisiana.

The MLRA includes parts of Camp Joseph T. Robinson, the

Little Rock Air Force Base, and the Pine Bluff Arsenal in

Arkansas and Fort Polk in Louisiana. It also includes the

Angelina, Davy Crockett, Kisatchie, Sabine, and Sam Houston

National Forests, parts of the Ouchita National Forest, and the

Big Thicket National Preserve. The northern half of the

Alabama and Coushatta Indian Reservation is in the part of this

area in Texas.

Physiography

This area is in the West Gulf Coastal Plain Section of the

Coastal Plain Province of the Atlantic Plain. It consists of level

to steep uplands that are intricately dissected by streams. Broad

flood plains and terraces are along some streams. Elevation

ranges from 80 to 650 feet (25 to 200 meters), increasing

gradually from southeast to northwest. Local relief is generally

less than 30 feet (9 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Lower Red-Ouachita (804), 29 percent; Red-Sulphur (1114), 26

percent; Neches (1202), 17 percent; Sabine (1201), 14 percent;

Trinity (1203), 7 percent; Louisiana Coastal (0808), 3 percent;

Galveston Bay-San Jacinto (1204), 3 percent; and Lower

Arkansas (1111), 1 percent. The headwaters of the Angelina,

Calcasieu, and Neches Rivers are in this area. The Trinity River

passes through the far western part of the area. Tributaries of the

Ouachita and the Sabine Rivers also drain the area. The Saline
432 Major Land Resource Areas

River in Arkansas and Louisiana and the Little, Black Lake

Bayou, Calcasieu, and Bayou D’Arbonne Rivers in Louisiana

are National Wild and Scenic Rivers.

Geology

Tertiary and Cretaceous marine sediments underlie most of

this area. Tertiary units include the Wilcox and Midway

Groups, the Claiborne Group, the Jackson Group, the Catahoula

Formation, and the Willis Formation. They consist of

interbedded sandstone, siltstone, and shale and unconsolidated

sands, silts, and clays. The Reklaw and Weches Formations in

the Claiborne Group form the Redland area in east Texas. The

Cretaceous marine sediments of the Fleming and Oakville

Formations are of minor extent in the area. They consist of

calcareous clays and marls. Sand, silt, and clay alluvium is

under the flood plains and terraces along the major drainages.

Climate

The average annual precipitation in this area is 39 to 63

inches (990 to 1,600 millimeters). It increases from northwest

to southeast. Most of the rainfall occurs as frontal storms in

spring and early summer. High-intensity, convective

thunderstorms occur in late summer and in fall. Some heavy

rains occur during tropical storms in winter. The average

annual temperature is 61 to 68 degrees F (16 to 20 degrees C).

The freeze-free period averages 270 days. It ranges from 235

days in the northern part of the area to 305 days in the

southern part.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 6.5%; ground water, 7.8%

Livestock—surface water, 3.5%; ground water, 4.6%

Irrigation—surface water, 3.1%; ground water, 2.3%

Other—surface water, 21.0%; ground water, 51.3%

The total withdrawals average 3,050 million gallons per day

(11,545 million liters per day). About 66 percent is from ground

water sources, and 34 percent is from surface water sources. The

water generally is abundant because of precipitation, perennial

streams, and the supply of ground water. Even though summer

rainfall is generally adequate for crops, droughts are common.

There is a summer moisture deficit of 2 to 6 inches (50 to 150

millimeters). Wet soils must be drained before they can be used

for crops. Several large reservoirs on the major streams provide

municipal and industrial water and also serve as recreation

sites. The surface water in the area is used dominantly for

industry and for cooling thermoelectric power plants. Most of

the surface water is of good quality and is suitable for most uses

with some treatment. High concentrations of suspended

sediments, agricultural chemicals, and municipal and industrial

wastewater discharges contribute to some local water-quality

problems. The lower tributaries of the Ouachita River are

contaminated with wastes from oil and gas production. Fecalcoliform bacteria counts have caused water-quality problems

on the Red River near Shreveport and in the Toledo Bend

Reservoir on the Sabine River. A low level of dissolved oxygen

is a problem in rivers below reservoirs where deep, oxygendeficient water is released. Flooding is a concern in many parts

of the area.

The principal sources of ground water in this area are

bedrock aquifers. They include the Carrizo-Wilcox aquifer in

Texas and Louisiana, the Trinity Group in Texas, the Cockfield

and Sparta aquifers in Arkansas and Louisiana, the Wilcox

aquifer in Arkansas, and the Pliocene-Miocene aquifers in

Louisiana. The Wilcox aquifer in southwest Arkansas is not

used extensively in this area. The ground water is used

primarily for industry, but it also is used for public supply. Most

rural landowners rely on the bedrock aquifers for domestic and

livestock water. The median level of total dissolved solids is

typically less than 400 parts per million (milligrams per liter),

but water in the Trinity Group near the Texas-Oklahoma State

line has a median level of 619 parts per million (milligrams per

liter). The ground water is soft in Louisiana and Arkansas, but it

is moderately hard to very hard in Texas. The iron content can

be very high in some areas in Arkansas, and it may also cause

some problems in the part of the area in Louisiana. A declining

water level is a problem in the Trinity Group aquifer in Texas.

About 30 percent of the samples from this aquifer exceeded the

10 parts per million (milligrams per liter) national standard for

nitrate in drinking water. The water in the Pliocene-Miocene

sands in west-central Louisiana has high levels of fluoride, and

its color limits its use for drinking water. Locally, the color of

the water in the Cockfield and Sparta aquifers in Louisiana

limits the use of those aquifers for public supply.

Soils

The dominant soil orders in this MLRA are Alfisols and

Ultisols. The soils in the area dominantly have a thermic soil

temperature regime, a udic or aquic soil moisture regime, and

siliceous, mixed, or smectitic mineralogy. They generally are

very deep, well drained to poorly drained, and loamy or clayey.

Hapludults formed in residuum (Cuthbert and Kirvin series) and

marine sediments (Sacul series) on hills and ridges. Paleudults

formed in marine sediments (Bowie and Malbis series) and

mixed marine sediments and alluvium (Ruston series) on

uplands. Endoaquults (Amy series) formed in old alluvium on

stream terraces. Fragiudults (Savannah series) formed in mixed

marine sediments and alluvium on uplands and stream terraces.

Hapludalfs (Eastwood and Woodtell series) formed in marine

sediments on hills and ridges. Glossaqualfs formed in alluvium
of the United States 433

on flood plains and stream terraces (Guyton series) and in old

alluvium on stream terraces (Wrightsville series).

Biological Resources

This area supports pine-hardwood vegetation. The dominant

trees are loblolly pine, shortleaf pine, sweetgum, southern red

oak, white oak, flowering dogwood, and post oak. American

beautyberry, greenbrier, hawthorns, and berry vines are

included in the woody understory. Little bluestem and pinhole

bluestem are the dominant herbaceous species. Other major

grasses include beaked panicum, longleaf uniola, spike uniola,

and yellow Indiangrass. The plant community has many species

of low-growing panicums and paspalums and perennial forbs.

The major wildlife species in this area include white-tailed

deer, coyote, beaver, raccoon, skunk, opossum, muskrat, mink,

cottontail, squirrel, weasel, armadillo, and mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 2%

Grassland—private, 18%

Forest—private, 65%; Federal, 4%

Urban development—private, 6%

Water—private, 3%; Federal, 1%

Other—private, 1%

The forested areas in this MLRA are used for the production

of lumber and pulpwood. The cleared land is used mostly for

pasture and hay. Where the water supply is adequate, such crops

as corn, grain sorghum, oats, soybeans, peanuts, rice, and

vegetables are grown.

The major resource concerns are water erosion, wetland

restoration, and water supplies for livestock. Conservation

practices on cropland generally include buffer strips, which

help to control erosion and runoff. They also include the proper

use and timing of irrigation. 

Figure 134-1: Location of MLRA 134 in Land Resource Region P.

134—Southern Mississippi Valley Loess

This area is in Mississippi (39 percent), Tennessee (23 percent),

Louisiana (15 percent), Arkansas (11 percent), Kentucky

(9 percent), Missouri (2 percent), and Illinois (1 percent). It

makes up about 26,520 square miles (68,715 square

kilometers). The northern part of the area includes Paducah and

Murray, Kentucky; Paragould, Jonesboro, and Forrest City,

Arkansas; and Memphis, Dyersburg, Bartlett, and Germantown,

Tennessee. The southern part includes Yazoo City, Clinton, and

Jackson, Mississippi, and Baton Rouge, Opelousas, Lafayette,

and New Iberia, Louisiana. Interstates 24, 55, 40, 20, 12, 49,

and 10 cross this area. The area includes the Homochitto

National Forest in Mississippi, the St. Francis National Forest in

Arkansas, and the Shawnee National Forest in Illinois. A

number of State parks and a few national wildlife refuges are in

the southern part of this MLRA.

Physiography

This area is in the Coastal Plain Province of the Atlantic

Plain. Most of the part of the area east of the Mississippi River

is in the East Gulf Coastal Plain Section of the province. Parts

of the western edge of the area, the part of the area in Arkansas,

and the isolated part in northern Louisiana are in the

Mississippi Alluvial Plain Section. The farthest southwest part

in Louisiana is in the West Gulf Coastal Plain Section. The

sharply dissected plains in this MLRA have a loess mantle that

is thick at the valley wall and thins rapidly as distance from the

valley wall increases. Valley sides are hilly to steep, especially

in the western part of the area. The intervening ridges generally

are narrow and rolling, but some of the interfluves between the

upper reaches of the valleys are broad and flat. Stream valleys

are narrow in the upper reaches but broaden rapidly

downstream and have wide, flat flood plains and meandering

stream channels. Elevation ranges from 80 to 600 feet (25 to

185 meters). Local relief is mainly 10 to 20 feet (3 to 6 meters),

but it can be 80 to 165 feet (25 to 50 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Lower Mississippi-Hatchie (0801), 28 percent; Lower

Mississippi-Big Black (0806), 20 percent; Lower MississippiSt. Francis (0802), 12 percent; Lower Mississippi-Yazoo

(0803), 12 percent; Lower Mississippi-Lake Maurepas (0807), 9

percent; Boeuf-Tensas (0805), 5 percent; Louisiana Coastal

(0808), 4 percent; Pearl (0318), 4 percent; Lower Tennessee
434 Major Land Resource Areas

(0604), 4 percent; and Lower Ohio (0514), 2 percent. There are

no major rivers in the part of this area west of the Mississippi

River. A tributary of the Tennessee River (and lake) is in the

part of this area in the southwest corner of Kentucky. The Obion

and Hatchie Rivers are in the part of the area in Tennessee. The

Hatchie River is a National Wild and Scenic River. Many of the

tributaries of the Yazoo River are in the part of the area in

northern Mississippi. The Big Black River crosses this area in

southern Mississippi. The Mississippi River is in the extreme

southeast corner of the area, near Baton Rouge, Louisiana.

Geology

This area is mantled with loess, which varies in thickness.

The area is underlain by unconsolidated sand, silt, and clay,

mainly of marine origin. Crowley’s Ridge is underlain by

Pliocene sand and gravel. The seas extended up the present-day

valley of the Mississippi River in Tertiary time, when these

sediments were deposited by rivers draining the surrounding

uplands. Throughout Quaternary and Recent time, the valley

floor received fine grained sediments each time the Mississippi

River flooded. After these sediments dried, winds picked them

up and deposited them as loess in the higher areas on each side

of the valley. There are five known periods of loess deposition

in the area. The surface deposit is the Peoria Loess, which is of

Late Wisconsin age (about 10,000 years ago). Pre-Peorian

Loess, which is of Middle Wisconsin age (about 20,000 to

40,000 years ago), occurs in some areas. This loess is thinner

than the Peorian Loess and is generally redder or darker.

Loveland-Sicily Island Loess, which is of pre-Wisconsin age

(85,000 to 130,000 years ago), is at the surface in some areas in

the southern part of this MLRA. It has a well developed reddish

paleosol (buried soil). Two other loess deposits have been

described on Crowley’s Ridge. They have been identified as

Marianna Loess and Crowley’s Ridge Loess. These deposits are

not exposed at the surface. They have well developed

paleosols.

Climate

The average annual precipitation in this area increases from

north to south. In most of this area, it is 47 to 60 inches (1,195

to 1,525 millimeters). It is 61 to 70 inches (1,550 to 1,780

millimeters) in parts of the extreme southern end of the area.

The maximum precipitation occurs in winter and spring. The

precipitation decreases gradually throughout the summer,

except for a moderate increase in midsummer. Rainfall occurs

primarily as high-intensity, convective thunderstorms, but

moderate-intensity tropical storms can produce large amounts

of rainfall during winter in the southern part of the area.

Snowfall generally occurs in the northern part of the area. The

average annual snowfall in Stoddard County, Missouri, is 11

inches (28 centimeters). South of the Missouri-Arkansas State

line, snowfall occurs but is rare. The average annual

temperature is 57 to 68 degrees F (14 to 20 degrees C),

increasing from north to south. The freeze-free period averages

270 days and ranges from 215 to 325 days, increasing in

length from north to south.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 2.3%; ground water, 5.8%

Livestock—surface water, 0.7%; ground water, 2.0%

Irrigation—surface water, 5.1%; ground water, 18.1%

Other—surface water, 61.7%; ground water, 4.3%

The total withdrawals average 5,270 million gallons per day

(19,945 million liters per day). About 30 percent is from ground

water sources, and 70 percent is from surface water sources.

Precipitation is abundant, but most streams are small and flow

intermittently. They flow most of the time in winter and spring.

In summer and autumn, however, they flow only during and

immediately after storms. Reservoirs store water for use when

flows in streams decline. In the uplands, ponds and rural water

systems are the main sources of water for domestic use and

livestock. The surface water in the area is suitable for almost all

uses. Most of the water used is for cooling thermoelectric power

plants.

Ground water is abundant in this area, but shallow wells

provide small quantities of water. In the uplands, shallow wells

are used to fill cisterns for domestic use and livestock. Deep

wells in the underlying unconsolidated sand and gravel of

Cretaceous and Tertiary age yield large quantities of water.

Most of the ground water east of the Mississippi River is

suitable for all uses. It is soft and generally has less than 200

parts per million (milligrams per liter) total dissolved solids.

Some of the water in the part of this area in Kentucky requires

treatment for high levels of iron if it is to be used as drinking

water.

In the part of Louisiana west of the Mississippi River, water

from the Chicot aquifer system exceeds the drinking water

standards for iron and water from the alluvial aquifer generally

is not suitable for drinking because of high levels of total

dissolved solids and iron and hardness. In Arkansas, water from

the alluvial aquifer is very hard and has a median level of iron

of almost 4,000 parts per billion (micrograms per liter). Water

from the Sparta and Wilcox aquifers is soft, but most samples

tested show levels of iron exceeding the 300 parts per billion

(micrograms per liter) secondary standard for drinking water. All

of the water west of the Mississippi River is very fresh and has

median levels of total dissolved solids in the range of 100 to

350 parts per million (milligrams per liter).
of the United States 435

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, Inceptisols, and Ultisols. The soils in the area are very

deep or deep, are medium textured, and have a thermic soil

temperature regime, a udic soil moisture regime, and mixed

mineralogy.

Well drained, nearly level to very steep Hapludalfs

(Memphis series) are on uplands. Nearly level to steep, well

drained Hapludalfs (Memphis, Coteau, and Feliciana series),

moderately well drained and somewhat poorly drained

Fraglossudalfs (Olivier, Grenada, and Calloway series),

moderately well drained Fragiudalfs (Loring series), and well

drained Eutrudepts (Natchez series) formed in thick deposits of

loess. Nearly level to gently sloping, somewhat poorly drained

Epiaqualfs (Patoutville series), moderately well drained

Fragiudults (Gigger, Toula, and Tangi series), well drained to

somewhat poorly drained Hapludalfs (Colyell and Dexter

series), and well drained Paleudults (Lytle series) formed in

deposits of loess 2 to 4 feet (1 meter) thick. Nearly level and

very gently sloping, somewhat poorly drained and poorly

drained Glossaqualfs (Calhoun, Encrow, and Frost series),

somewhat poorly drained Glossudalfs (Egypt series), somewhat

poorly drained Hapludalfs (Satsuma series), and somewhat

poorly drained Argiaquolls (Jeanerette series) formed in a thin

mantle of loess over loamy alluvium or mixed loess and loamy

alluvium. Deep, gently sloping, well drained Eutrudepts

(Weyanoke series), somewhat poorly drained Fragiudults (Bude

series), and somewhat poorly drained Fraglossudalfs (Fluker

series) formed in silty material or in a mantle of loess and the

underlying late Pleistocene loamy terrace material.

In the eastern part of the area, where the loess mantle thins,

well drained Paleudalfs (Lexington series), moderately well

drained Fragiudalfs (Dulac and Providence series), well drained

Hapludults (Brandon and Silerton series), and well drained

Paleudults (Smithdale series), all of which are gently sloping to

steep, are on ridgetops and side slopes. Well drained

Dystrudepts (Ariel series), moderately well drained Udifluvents

(Collins series), moderately well drained Dystrudepts

(Oaklimeter series), and somewhat poorly drained Fluvaquents

(Gillsburg series) are on flood plains.

Biological Resources

This area supports hardwood-pine vegetation. Cherrybark

oak, Shumard oak, white oak, post oak, southern red oak, and

southern magnolia are widely distributed. Loblolly pine and

shortleaf pine are the dominant pines. Yellow-poplar, white ash,

swamp chestnut, cottonwood, sweetgum, and black walnut are

important species on the flood plains. Loblolly pine and

shortleaf pine are on a wide variety of sites, mainly the eroded

soils on uplands and ridges. Other hardwood species that

commonly grow in this area are white oak, basswood,

sweetgum, water oak, American elm, blackgum, sycamore,

sassafras, southern red oak, chinkapin oak, American beech,

and hickory. Beech-magnolia-holly forests are dominant on

narrow ridges and in steep ravines in the Tunica Hills of

Louisiana.

Some of the major wildlife species in this area are whitetailed deer, red fox, gray fox, raccoon, opossum, skunk,

muskrat, cottontail, gray squirrel, fox squirrel, bobwhite quail,

and mourning dove. The species of fish in the area include

largemouth bass, bluegill, and bullhead.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 36%

Grassland—private, 13%

Forest—private, 38%; Federal, 2%

Urban development—private, 7%

Water—private, 2%

Other—private, 2%

Most of this area is in farms. A small acreage is federally

owned. About one-third of the area is cropland, but the

proportion varies greatly from county to county, depending on

the soils and the topography. This is largely a cash-crop area.

Cotton, corn, rice, soybeans, and wheat are the major crops.

Strawberries are important in Louisiana. Feed grains and forage

are grown on dairy farms. Less than 15 percent of the area is

pasture or hayland. About two-fifths is forest of mixed pine and

hardwoods. Lumber is the major forest product, and some

pulpwood is harvested. The present trend is toward the

conversion of pasture and forest to cropland. Some areas are

used for urban development, which is expanding near the

metropolitan areas.

The major soil resource concerns are water erosion,

maintenance of the content of organic matter and productivity

of the soils, and management of soil moisture. Water erosion is

a hazard in sloping areas that are bare because of tree

harvesting. Conservation practices on forestland generally

include systems of tree residue management and reforestation.

Conservation practices on cropland generally include crop

residue management, which increases the content of organic

matter in the soils, and applications of lime in areas of low pH.

Many of the soils remain wet or have a high water table for

some or most of the year. Measures that improve drainage

should be applied, or the crops adapted to the wet conditions

should be selected for planting. 
436 Major Land Resource Areas

Figure 135A-1: Location of MLRA 135A in Land Resource Region P.

135A—Alabama and Mississippi

Blackland Prairie

This area (shown in fig. 135A-1) is in Alabama (53 percent)

and Mississippi (47 percent). It makes up about 6,370 square

miles (16,510 square kilometers). Tupelo, Mississippi, is the

only major town in this MLRA. The small towns of Demopolis

and Uniontown are in west Alabama. The cities of Montgomery

and Selma are just outside this area, on terraces along the

Alabama River, which bisects the MLRA. Interstates 20 and

20/59 cross parts of this area, and U.S. Highway 80 runs

through the center of the part of the MLRA in Alabama. The

Bienville National Forest is in the part in Mississippi.

Physiography

This area is in the East Gulf Coastal Plain Section of the

Coastal Plain Province of the Atlantic Plain. The northern part

of the area is a slightly elevated plain that is hilly, and the

separate southwestern part is locally known as the Jackson

Prairie portion of the East Gulf Coastal Plain Section in

Mississippi. Elevation ranges from 100 to 590 feet (30 to 180

meters). Local relief is mainly 50 to 100 feet (15 to 30 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Mobile-Tombigbee (0316), 55 percent; Alabama (0315), 28

percent; Pascagoula (0317), 10 percent; and Pearl (0318), 7

percent. Tributaries of the Tombigbee, Pearl, and Pascagoula

Rivers cross the part of this area in Mississippi. The valleys

along the Tombigbee and Alabama Rivers separate the three

parts of this area in Alabama.

Geology

Most of this area is underlain by Cretaceous-age clay, marl,

soft limestone, or chalk of the Selma Group. The Jackson Prairie

part, in southern Mississippi, and parts of the area in southwest

Alabama are underlain by Tertiary-age clay, marl, soft

limestone, or chalk of the Vicksburg and Jackson Groups.

Climate

The average annual precipitation in this area is 53 to 61

inches (1,345 to 1,550 millimeters). The maximum

precipitation occurs early in winter, in spring, and in

midsummer. The lowest rainfall occurs in autumn. The rainfall

typically occurs during high-intensity, convective thunderstorms

in summer, but some heavy rains occur during tropical storms in

winter. The average annual temperature is 60 to 65 degrees F

(16 to 18 degrees C), decreasing from south to north. The

freeze-free period averages 250 days and ranges from 230 to

275 days, increasing in length to the south.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 7.3%; ground water, 9.3%

Livestock—surface water, 2.2%; ground water, 9.3%

Irrigation—surface water, 1.8%; ground water, 7.3%

Other—surface water, 61.9%; ground water, 0.9%

The total withdrawals average 55 million gallons per day

(208 million liters per day). About 27 percent is from ground

water sources, and 73 percent is from surface water sources.

Precipitation and perennial streams are important sources of

water. Ponds provide water for livestock and are used locally for

recreation. A few large reservoirs are available for recreation

and other uses. The surface water in the area is suitable for all

uses. Most of it is used for cooling thermoelectric power plants.

Moderately deep and deep wells are the principal sources of

ground water for both domestic and municipal uses in this area.

In Alabama, good-quality ground water is obtained primarily

from Tertiary and Cretaceous sand aquifers. The southern part

of the area in Alabama also has access to the Floridan and

Citronelle aquifers. The ground water in Alabama generally is

hard but is low in total dissolved solids. Most of the part of this

area in Mississippi has no significant aquifers. The Cockfield

silty clay and sand aquifer underlies parts of the isolated portion

of this area in southern Mississippi. The water from this aquifer

is soft and generally has less than 400 parts per million

(milligrams per liter) total dissolved solids. It generally exceeds

the color standard for drinking water, which is 15 units. The

color has no known effects on health.
of the United States 437

Soils

The dominant soil orders in this MLRA are Inceptisols and

Vertisols. The soils in the area dominantly have a thermic soil

temperature regime, a udic or aquic soil moisture regime, and

smectitic or carbonatic mineralogy. They are shallow to very

deep, generally well drained to somewhat poorly drained, and

loamy or clayey. Epiaquepts (Leeper and Urbo series),

Epiaquerts (Sucarnoochee and Houlka series), and Hapludolls

(Catalpa series) formed in clayey alluvium on flood plains.

Eutrudepts formed in loamy alluvium on flood plains (Marietta

series) and in clayey sediments and residuum on uplands

(Sumter series). Dystruderts (Oktibbeha, Hannon, Watsonia, and

Vaiden series), Hapluderts (Brooksville, Okolona, and Houston

series), and Paleudalfs (Kipling and Searcy series) formed in

clayey sediments on uplands. Udorthents (Demopolis series)

formed in residuum on ridges and hills.

Biological Resources

This area supports both deciduous hardwoods and conifers.

Red oak, white oak, sweetgum, blackgum, loblolly pine, and

shortleaf pine are the dominant overstory species. Forests of

mixed oaks and loblolly pine are dominant on acid soils.

Mixed hardwood forests dominate flood plains, and forests of

eastern redcedar and sugarberry dominate alkaline hills and

side slopes. Eastern redcedar, dogwood, and osage orange are

the major midstory species. Japanese honeysuckle, greenbrier,

little bluestem, native lespedezas, plumegrass, low panicums,

sedges, and rushes are the dominant understory species.

Some of the major wildlife species in this area are whitetailed deer, cottontail, squirrel, turkey, bobwhite quail, and

mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 16%

Grassland—private, 29%

Forest—private, 45%; Federal, 3%

Urban development—private, 4%

Water—private, 2%

Other—private, 1%

Most areas have been disturbed, and only small remnants of

the former prairie vegetation remain. The major crop on the

cropland in the area is soybeans, but corn, small grains, and

cotton also are grown. Pastures are used mainly for beef

production, but in some areas dairying is an important industry.

About three-fourths of the forestland in the area is privately

owned, and about one-fourth is owned by industry. The

production of pond-raised catfish is important in west Alabama.

Some areas are used for urban development.

The major soil resource concerns are water erosion,

maintenance of the content of organic matter and productivity

of the soils, and management of soil moisture. Water erosion

and the infestation of Johnsongrass are major management

concerns in cultivated areas. Conservation practices on

cropland generally include systems of crop residue

management, cover crops, crop rotations, water disposal, pest

management, and nutrient management. The most important

conservation practice on pasture is prescribed grazing. Pastures

commonly are overseeded with small grains and/or legumes to

supplement forage production during winter. Haying also helps

to provide supplemental feed during the long winters.

Critically eroding areas and areas where animals congregate

should be monitored and treated. 

Figure 135B-1: Location of MLRA 135B in Land Resource Region P.

135B—Cretaceous Western Coastal Plain

This area (shown in fig. 135B-1) is in Arkansas (56 percent)

and Oklahoma (44 percent). It makes up about 3,970 square

miles (10,290 square kilometers). The towns of Ashdown, De

Queen, Nashville, Murfreesboro, and Arkadelphia, Arkansas,

and Broken Bow, Durant, Caddo, Hugo, and Idabel, Oklahoma,

are in the area. U.S. Highway 71 bisects the area from north to

south, and Interstate 30 crosses the eastern half of the area, in

Arkansas. Crater of Diamonds State Park is in the part of this

area in Arkansas, and the Ouachita National Forest is in the part

in Oklahoma.

Physiography

This MLRA is in the West Gulf Coastal Plain Section of the

Coastal Plain Province of the Atlantic Plain. It consists of
438 Major Land Resource Areas

nearly level to moderately sloping uplands and level and

nearly level, low terraces and flood plains. Valley floors, side

slopes, and ridgetops are underlain by clay, marl, and chalk.

These parent materials are highly erodible, and gullies have cut

this area. Elevation generally ranges from 80 to 350 feet (25 to

105 meters), but it is less than 80 feet (25 meters) on some of

the more prominent valley floors and is more than 360 feet (110

meters) on a few ridgetops. Local relief is mainly a few meters.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows: RedSulphur (1114), 75 percent, and Lower Red-Ouachita (0804),

25 percent. The Little River flows from the western part of this

MLRA, in Oklahoma, into Millwood Lake, in Arkansas. Also,

the Cossatot and Saline Rivers flow into Millwood Lake from

the northern part of the area in Arkansas.

Geology

Cretaceous marine sediments underlie almost all of this area.

Geologic members of the Lower Cretaceous include a basal

member of gravel and conglomerate rocks. Other formations are

dominantly limestone that is crystalline and contains many

fossils. Gypsum is mined commercially from the limestone in

parts of the MLRA. Members of the Upper Cretaceous consist

of clay marls, thin limestones, sandy marls, and some fine

grained sands. Other formations consist of chalk and marly

chalk, which are hard and contain many fossils.

Climate

The average annual precipitation in this area is 41 to 55

inches (1,040 to 1,400 millimeters). Most of the rainfall occurs

as frontal storms in spring and early summer. Some highintensity, convective thunderstorms occur in summer. The

average seasonal snowfall is 5 inches (12 centimeters). The

average annual temperature is 61 to 64 degrees F (16 to 18

degrees C). The freeze-free period averages about 250 days and

ranges from 235 to 265 days, increasing in length to the south.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 11.6%; ground water, 6.6%

Livestock—surface water, 1.9%; ground water, 2.4%

Irrigation—surface water, 0.0%; ground water, 1.2%

Other—surface water, 70.3%; ground water, 6.1%

The total withdrawals average 82 million gallons per day

(310 million liters per day). About 16 percent is from ground

water sources, and 84 percent is from surface water sources.

Precipitation and perennial streams are important sources of

water in this area. Ponds provide water for livestock and locally

are used for recreation. A few large reservoirs are available for

recreation and other uses. The dominant uses of the surface

water are for industry and for cooling thermoelectric power

plants, but some communities use the water for public supply.

Most of the surface water is of good quality and is suitable for

most uses with some treatment. High concentrations of

suspended sediments, agricultural chemicals, and municipal and

oil and gas production wastewater discharges contribute to some

local water-quality problems.

The principal sources of ground water in this area are

bedrock aquifers, including the Antlers aquifer in Oklahoma

and the Nacatoch aquifer in Arkansas. The Antlers aquifer is the

northern end of the carbonate and clastic rock aquifer in Texas,

which is called the Trinity Group. The ground water in this area

is used primarily for public supply. Most rural landowners also

rely on the bedrock aquifers for domestic water. The median

level of total dissolved solids is close to 500 parts per million

(milligrams per liter) in the Nacatoch aquifer and 619 parts per

million (milligrams per liter) in the Antlers aquifer. The ground

water is soft to hard in Arkansas and very hard in Oklahoma.

The iron content may require treatment in some areas in

Arkansas. About 30 percent of the samples from the Antlers

aquifer exceeded the 10 parts per million (milligrams per liter)

national standard for nitrate in drinking water.

Soils

The dominant soil orders in this MLRA are Inceptisols and

Alfisols. Entisols and Vertisols are of lesser extent. The soils in

the area dominantly have a thermic soil temperature regime, an

ustic soil moisture regime, and smectitic or mixed mineralogy.

They generally are moderately deep or deep over soft limestone

or chalk and typically shrink, swell, and crack. Nearly level to

strongly sloping, well drained Eutrudepts (Sumter series) and

moderately well drained to poorly drained Hapludalfs

(Oktibbeha and Vaiden series) are on wide ridgetops and narrow

side slopes. Shallow Udorthents (Demopolis series) locally are

of small extent. Moderately well drained to poorly drained,

nearly level to gently sloping Epiaquepts (Leeper series),

Epiaquerts (Terouge series), and Hapluderts (Trinity series) are

on bottom land and in low areas on uplands. The outer

perimeter of the area is intermittently ringed with moderately

well drained to somewhat poorly drained Paleudalfs (Boswell

and Susquehanna series) and moderately well drained and well

drained, shallow to very deep Hapludults (Sacul, Tiak, and

Saffell series).

Biological Resources

This area dominantly supports deciduous hardwoods. A few

areas are suitable for pine. Red oak, white oak, sweetgum, and

blackgum are the dominant overstory species. Eastern redcedar,

dogwood, and osage orange are the major midstory species.

Japanese honeysuckle, greenbrier, little bluestem, native
of the United States 439

lespedezas, plumegrass, low panicums, sedges, and rushes are

the dominant understory species.

Some of the major wildlife species in this area include whitetailed deer, coyote, armadillo, bobcat, beaver, raccoon, skunk,

mink, cottontail, turkey, and mourning dove. The species of

fish in the area include channel catfish, flathead catfish, white

bass, largemouth black bass, and bluegill.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 5%

Grassland—private, 25%

Forest—private, 54%; Federal, 9%

Urban development—private, 3%

Water—private, 3%

Other—private, 1%

Nearly all of this area is privately owned land consisting of

farm woodlots and pasture. The poultry business has grown into

a major industry in the area. Most of the cropland in the area is

on the less sloping soils. Small grains and hay are the major

crops. Orchards, vineyards, vegetable crops, and watermelons

are important locally. Pastures on the bottom land along small

streams and throughout cleared parts of the uplands support a

mixture of cultivated and native grasses and legumes.

The major resource concerns are excessive nutrients and

organic material in surface water; forest and pasture

productivity, health, and vigor; inadequate water sources for

domestic animals; and structure failures of dams caused by a

high content of smectitic clay in the soils. The structure failures

result in the formation of ponds and small lakes. Conservation

practices on cropland generally include proper management of

the application of chicken litter and riparian forest buffers.

Conservation practices on pasture generally include proper

management of the application of chicken litter, prescribed

grazing, ponds, pipelines, development of springs, and riparian

forest buffers. Conservation practices on forestland generally

include forest stand improvement and riparian forest buffers.

The riparian forest buffers on cropland, pasture, and forestland

help to preserve water quality. 

Figure 136-1: Location of MLRA 136 in Land Resource Region P.

136—Southern Piedmont

This area (shown in fig. 136-1) is in North Carolina (29

percent), Georgia (27 percent), Virginia (21 percent), South

Carolina (16 percent), and Alabama (7 percent). It makes up

about 64,395 square miles (166,865 square kilometers). It

includes the cities of Auburn, Alabama; Atlanta, Georgia;

Greenville, South Carolina; Charlotte, Raleigh, and WinstonSalem, North Carolina; and Richmond and Arlington, Virginia.

Interstate 85 runs from Auburn, Alabama, to Greensboro, North

Carolina, in this MLRA. Other interstate highways in this area

are, from south to north, Interstates 75, 20, 26, 40, 64, 66, and

95. The MLRA includes the Talladega National Forest and

Horseshoe Bend National Military Park in Alabama; Kennesaw

Mountain National Battlefield Park, the Oconee National

Forest, and parts of the Chattahoochee National Forest in

Georgia; King’s Mountain National Military Park, Cowpens

National Battlefield, and Sumter National Forest in South

Carolina; parts of the Pisgah and Uwharrie National Forests and

Guilford C.H. National Military Park in North Carolina;

Appomattox Courthouse National Historic Park, Fort Pickett,

Fredericksburg, and Spotsylvania National Military Park, and

Quantico Marine Corps Combat Development Command in

Virginia; and Thomas Jefferson’s home in Monticello, Virginia.

The farm of Hugh Hammond Bennett, the “father of soil

conservation,” is in this MLRA. Bennett designed many of the

early conservation practices to address the severe erosion that

historically occurred in this area. A number of State forests and

State parks are throughout the area.

Physiography

Almost all of this area is in the Piedmont Upland Section of

the Piedmont Province of the Appalachian Highlands. A very

small part of the MLRA, in central North Carolina, is in the

Atlantic Plain Division. A very small part in the Roanoke,

Virginia, area is on the eastern edge of the Blue Ridge Province

of the Appalachian Highlands. This MLRA is a rolling to hilly

upland with a well defined drainage pattern. Streams have

dissected the original plateau, leaving narrow to fairly broad

upland ridgetops and short slopes adjacent to the major

streams. The valley floors are generally narrow and make up

about 10 percent or less of the land area. The associated stream

terraces are minor. Elevation ranges from 330 to 1,310 feet (100

to 400 meters).
440 Major Land Resource Areas

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Edisto-Santee (0305), 18 percent; Chowan-Roanoke (0301), 14

percent; Apalachicola (0313), 10 percent; Pee Dee (0304), 10

percent; Ogeechee-Savannah (0306), 10 percent; Alabama

(0315), 9 percent; Altamaha-St. Marys (0307), 9 percent; Lower

Chesapeake (0208), 9 percent; Neuse-Pamlico (0302), 5

percent; Cape Fear (0303), 5 percent; and Potomac (0207), 1

percent. Some of the major rivers in this MLRA are, from north

to south, the Roanoke, Cape Fear, Savannah, Altamaha,

Chattahoochee, and Alabama Rivers. These rivers typically

form within the Piedmont Province and flow east and south

across the Coastal Plain Province and empty into the Atlantic

Ocean or Gulf of Mexico. Reaches of the Rappahannock,

Rivanna, and Roanoke (Staunton) Rivers have been designated

National Wild and Scenic Rivers in Virginia.

Geology

Precambrian and Paleozoic metamorphic and igneous rocks

underlie almost all of this MLRA. The dominant metamorphic

rock types include biotite gneiss, schist, slate, quartzite,

phyllite, and amphibolite. The dominant igneous rock types are

granite and metamorphosed granite. Some gabbro and other

mafic igneous rocks also occur, and diabase dikes are not

uncommon. The Carolina Slate terrane occurs just east of an

imaginary centerline in this MLRA. It consists of metamorphic

rocks with some metavolcanics and metasediments. Scattered

graben basins, which are bounded by faults where the ground

between the faults has dropped down, occur from South

Carolina to south of Charlottesville and Richmond, Virginia.

These basins have Triassic and Jurassic siltstone, shale,

sandstone, and mudstone. River valleys have recent alluvium

and few terraces.

Climate

The average annual precipitation is 37 to 45 inches (940 to

1,145 millimeters) at the northern end of this area, is 45 to 60

inches (1,145 to 1,525 millimeters) at the southern end, and is

as much as 75 inches (1,905 millimeters) in a small, highelevation area in northeastern Georgia. The precipitation

generally is evenly distributed throughout the year. It is lowest

in autumn. Most of the rainfall occurs as high-intensity,

convective thunderstorms during the growing season.

Significant moisture also comes from the movement of warm

and cold fronts across the MLRA from November to April. High

amounts of rain can occur during hurricanes at the same time of

the year. Snowfall typically is light. The average annual

temperature is 53 to 64 degrees F (12 to 18 degrees C). The

freeze-free period averages 230 days and ranges from 185 to

275 days. Both the mean annual temperature and length of the

freeze-free period increase from north to south and with

decreasing elevation.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 11.1%; ground water, 1.1%

Livestock—surface water, 0.7%; ground water, 0.2%

Irrigation—surface water, 0.5%; ground water, 0.1%

Other—surface water, 83.9%; ground water, 2.5%

The total withdrawals average 12,720 million gallons per day

(48,145 million liters per day). This MLRA ranks third among

all of the MLRAs in total amount of water used. About 4

percent is from ground water sources, and 96 percent is from

surface water sources. Precipitation, perennial streams, rivers,

and lakes provide an abundance of good-quality, soft surface

water throughout this MLRA. Small farm ponds are important

sources of water for livestock. Industry and thermoelectric

power plants use most of the surface water in this area. Toxins,

nutrients, and sediment are the primary contaminants in the

water. Fecal coliform contamination from point and nonpoint

sources is a problem in South Carolina.

Ground water supplies are relatively small, but shallow and

deep wells in the crystalline bedrock aquifer are the principal

sources of water for domestic use in the area. The water is drawn

from joints, fractures, and bedding planes in the crystalline

rocks. It generally is soft, but it can be hard or very hard,

depending on the type of rock from which the well is drawing

its water. High concentrations of manganese and iron can be a

problem in some wells. Naturally high levels of radiation in the

ground water in this MLRA can cause radon gas problems in

basements.

Soils

The dominant soil orders in this MLRA are Ultisols,

Inceptisols, and Alfisols. The soils in the area dominantly have

a thermic soil temperature regime, a udic soil moisture regime,

and kaolinitic or mixed mineralogy. They are shallow to very

deep, generally well drained, and loamy or clayey. Hapludalfs

(Enon and Wilkes series), Hapludults (Badin, Nason, and Tatum

series), and Kanhapludults (Appling, Cecil, Georgeville,

Herndon, Madison, Pacolet, and Wedowee series) formed in

residuum on hills and ridges. Dystrudepts (Chewacla series)

formed in alluvium on flood plains. Udults in the Rhodic

subgroup (Davidson, Hiwassee, and Lloyd series) formed in old

alluvium on stream terraces or in residuum derived from mafic

rocks.

Biological Resources

The uplands in this area generally support a mixture of

hardwoods and pine. Loblolly pine, slash pine, white oak, red

oak, gum, yellow-poplar, and sycamore are the principal

species. Pine is dominant on eroded sites. Hardwoods or mixed
of the United States 441

stands of pine and hardwoods are on slightly eroded soils and

the flood plains along streams. The understory includes

dogwood, honeysuckle, pinehill bluestem, and briars.

Some of the major wildlife species in this area are whitetailed deer, cottontail, squirrel, bobwhite quail, and mourning

dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 9%

Grassland—private, 11%

Forest—private, 58%; Federal, 2%

Urban development—private, 15%

Water—private, 3%

Other—private, 2%

Most of this area is in small farms, but a sizable acreage is

controlled by forest products companies. Although most of the

land was once cultivated, much has reverted to mixed stands of

pine and hardwoods. Most of the open areas are used as pasture,

but some crops, such as soybeans, corn, cotton, and wheat and

other small grains, are grown in these areas. Tobacco is grown

to a lesser extent. Dairy cattle and poultry are important locally.

Rural land adjacent to the major cities is being converted to

residential development and associated urban development.

This land use conversion is occurring rapidly in the corridor

called the Piedmont Crescent, which extends from Atlanta,

Georgia, to Raleigh, North Carolina.

The major soil resource concerns are water erosion and the

increasing conversion of prime farmland and farmland of

statewide importance to urban uses. Conservation practices on

cropland generally include conservation tillage, crop residue

management, field borders, vegetative wind barriers, and

nutrient and pest management. 

Figure 137-1: Location of MLRA 137 in Land Resource Region P.

137—Carolina and Georgia Sand Hills

This area (shown in fig. 137-1) is in South Carolina (44

percent), Georgia (34 percent), North Carolina (21 percent), and

Alabama (1 percent). It makes up about 8,665 square miles

(22,450 square kilometers). It includes the towns of Sanford,

Pinehurst, and Fort Bragg, North Carolina; Columbia and

Aiken, South Carolina; Augusta and Columbus, Georgia; and

Phenix City, Alabama. Interstates 185, 75, 20, 26, and 77 cross

this area. Interstate 26 transects a major portion of the area from

east of Columbia, South Carolina, to west of Augusta, Georgia.

Forts Benning, Gordon, Jackson, and Bragg are in this MLRA.

The southeastern edge of the Uwharrie National Forest and the

Department of Energy’s nuclear materials production plant,

Savannah River Site, are in this area. The Ocmulgee

National Monument, just south of Macon, Georgia, is in the

MLRA.

Physiography

This area is in a transitional zone between the true Piedmont

and the Coastal Plain. Most of the area is in the Sea Island

Section of the Coastal Plain Province of the Atlantic Plain. Part

of the area in Alabama and the western half of the area in

Georgia are in the East Gulf Coastal Plain Section of the same

province and division. Parts of the inland edge and half of the

northern end of the area are in the Piedmont Upland Section of

the Piedmont Province of the Appalachian Highlands. This

MLRA is a dissected, rolling to hilly upland. Many of the more

dissected areas have stabilized dunes, resulting in very irregular

slopes. Elevation ranges from 165 to 660 feet (50 to 200

meters), increasing gradually from south to north. Local relief is

mainly 10 to 20 feet (3 to 6 meters), but a few hills are 80 to

165 feet (25 to 50 meters) above the adjacent areas.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Edisto-Santee (0305), 24 percent; Pee Dee (0304), 23 percent;

Apalachicola (0313), 16 percent; Ogeechee-Savannah (0306),

15 percent; Altamaha-St. Marys (0307), 11 percent; and Cape

Fear (0303), 11 percent. From North Carolina to Alabama, the

major rivers crossing this area are the Lumber, Pee Dee, Little

Lynches, Wateree, Congaree, North and South Forks of the

Edisto, Savannah, Brier, Ogeechee, Oconee, Ocmulgee, Flint,

and Chattahoochee Rivers.
442 Major Land Resource Areas

Geology

The Sand Hills area is just below the “fall line,” which marks

the boundary between the older crystalline rocks in the

Piedmont and the younger, unconsolidated sediments of the

Coastal Plain. Deep Cretaceous sands deposited in this ancient

shoreline area were reworked during periods of submergence of

the Coastal Plain in Pleistocene time. Several areas have

deposits of kaolin and high-silica sands that are mined.

Stabilized sand dunes are common in the area. Deposits of

siltstone, shale, and marl generally lie beneath the coastal plain

side of this area, and the crystalline rocks of the Piedmont lie

beneath the sands on the inland side.

Climate

The average annual precipitation in this area is 41 to 53

inches (1,040 to 1,345 millimeters). The maximum

precipitation occurs in midsummer, and the minimum occurs in

autumn. Rainfall occurs during high-intensity, convective

thunderstorms in summer. Snowfall is light if it occurs at all.

The average annual temperature is 59 to 65 degrees F (15 to 18

degrees C). The freeze-free period averages 250 days and ranges

from 220 to 280 days, increasing in length to the south.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 5.7%; ground water, 6.5%

Livestock—surface water, 0.4%; ground water, 0.3%

Irrigation—surface water, 0.3%; ground water, 0.5%

Other—surface water, 78.2%; ground water, 8.1%

The total withdrawals average 2,070 million gallons per day

(7,835 million liters per day). About 15 percent is from ground

water sources, and 85 percent is from surface water sources.

Precipitation, perennial streams, and aquifers provide an

abundance of water. The kind and amount of plant growth are

severely limited by low moisture in the rapidly permeable,

sandy soils that are dominant in this area. The surface water in

the area is suitable for all uses. Most of it is used for industry

and for cooling thermoelectric power plants.

Ground water is available in both the crystalline igneous

and metamorphic rocks aquifer and the Cretaceous sediments

aquifer in this area. Both of these aquifers have soft water that is

very low in total dissolved solids, having median

concentrations of less than 100 parts per million (milligrams

per liter). Water in the Cretaceous aquifer is a sodium

bicarbonate type and is typically used for industry and public

supply. It also is used for irrigating the many golf courses in

this area. In North Carolina, the Cretaceous aquifer is actually

called the surficial aquifer. Water from this aquifer in North

Carolina has low pH, so it can be corrosive. The Middendorf

sands are the primary sources of ground water in the part of this

area in Georgia. The water in these sands is similar in quality to

the water in the surficial aquifer in North Carolina. The

crystalline rocks aquifer has a calcium bicarbonate type of

water and supplies mostly domestic water in the area. The water

in some wells in the crystalline rocks exceeds the secondary

drinking water standard for iron.

Soils

The dominant soil orders in this MLRA are Ultisols and

Entisols. The soils dominantly have a thermic soil temperature

regime, a udic soil moisture regime, and kaolinitic or siliceous

mineralogy. They generally are very deep, well drained to

excessively drained, and loamy or sandy. Hapludults (Blaney

series) and Kanhapludults (Ailey, Pelion, and Vaucluse series)

formed in marine sediments on flats, hills, and ridges.

Kandiudults formed in marine sediments (Fuquay series) and

mixed marine and alluvial sediments (Troup series) on uplands.

Paleudults formed in marine sediments (Candor series) and

mixed marine and eolian deposits (Blanton series) on uplands

and stream terraces. Quartzipsamments (Lakeland series) formed

in mixed marine and eolian deposits on uplands.

Biological Resources

This area supports pine-oak vegetation. Longleaf pine is the

dominant species. Turkey oak, blackjack oak, bluejack oak,

and sand live oak also occur. Little bluestem, panicums,

pineland threeawn, and associated grasses and forbs make up

the ground cover.

Some of the major wildlife species in this area are whitetailed deer, red fox, gray fox, beaver, raccoon, opossum,

cottontail, gray squirrel, turkey vulture, black vulture, crow,

screech owl, barred owl, mallard, wood duck, bobwhite quail,

Carolina wren, and mourning dove. The large stands of longleaf

pine provide critical nesting areas for the red-cockaded

woodpecker, an endangered species.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 12%

Grassland—private, 4%

Forest—private, 58%; Federal, 10%

Urban development—private, 13%

Water—private, 1%

Other—private, 2%

Most of this area is in farms, most of which are part-time or

subsistence farms. About one-tenth of the area is federally

owned and used for military posts and training areas. The

forested areas support pine and scrub oaks. Pulpwood and some

lumber are the principal forest products. The cropland in the
of the United States 443

area is used mainly for corn or cotton. A substantial acreage in

the area is used for urban development.

The major resource concerns are controlling water erosion

and enhancing the available water capacity of the soils.

Conservation practices on cropland generally include systems

of crop residue management, diversions, and grassed

waterways. Field borders provide cover for bobwhite quail and

cottontail. Conversion to a permanent cover of vegetation has

been a continuing recommendation for the soils that are low in

natural productivity. 

Figure 138-1: Location of MLRA 138 in Land Resource Region P.

138—North-Central Florida Ridge

This area is entirely in Florida (fig. 138-1). It makes up about

2,240 square miles (5,810 square kilometers). Lake City and

Live Oak are the only towns of significant size in the area.

Interstate 75 crosses the entire length of this area, and it

intersects with Interstate 10 at the northern end of the area. The

southwest corner of the Osceola National Forest is in this area.

A number of State parks are throughout the area. The Stephen

Foster State Folk Culture Center is in the area.

Physiography

Most of this area is in the East Gulf Coastal Plain Section of

the Coastal Plain Province of the Atlantic Plain. The southern

one-quarter is in the Floridian Section of the same province and

division. This MLRA is on a sand-mantled limestone upland

that has an irregular, gently rolling topography. Many

limestone sinkholes, some filled with water, dot the area. Only a

few streams are in the area. Elevation ranges from 80 to 165 feet

(25 to 50 meters). Local relief is generally 10 to 20 feet (3 to 6

meters) but can be as much as 35 feet (10 meters).

The only Hydrologic Unit Area (identified by a four-digit

number) that makes up this MLRA is Suwannee (0311). The

Suwannee River originates in the Okefenokee Swamp northeast

of this area. It is spring-fed and flows through this MLRA. The

Alapaha and Withlacoochee Rivers join the Suwannee River in

the MLRA. Another Suwannee River tributary, the Santa Fe

River, crosses the southern part of the area.

Geology

This area is a young marine plain underlain by Tertiary-age

rocks that are primarily carbonates. Some of the oldest rocks in

Florida, from the Eocene age, are at the surface at the southern

end of this area. The rocks are progressively younger to the

north. They include very fine grained shale, mudstone,

limestone, and dolomite beds. A sandy marine deposit of

Pleistocene age occurs at the surface, overlying limestone in

most of the area.

Climate

The average annual precipitation in this area is 53 to 60

inches (1,345 to 1,525 millimeters). The maximum

precipitation occurs in summer, and the minimum occurs in

winter and late in autumn. Rainfall occurs during highintensity, convective thunderstorms in summer. The average

annual temperature is 67 to 69 degrees F (19 to 21 degrees C).

The freeze-free period averages 295 days and ranges from 280

to 305 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.5%; ground water, 17.9%

Livestock—surface water, 0.1%; ground water, 1.2%

Irrigation—surface water, 15.8%; ground water, 52.5%

Other—surface water, 2.1%; ground water, 10.0%

The total withdrawals average 95 million gallons per day

(360 million liters per day). About 82 percent is from ground

water sources, and 18 percent is from surface water sources. The

abundant rainfall and the Floridan aquifer are the principal

sources of water in the area. The many lakes and ponds are used

for recreation. The Suwannee River has been designated as an

“Outstanding Florida Water” by the State. One thermoelectric

power plant uses river water for cooling. With the exception of

one tributary below an active phosphate mine, the river water is

suitable for almost all uses.

Shallow and deep wells in the Floridan aquifer provide water

for public supply, domestic use, industry, mining, livestock,

and irrigation in this MLRA. This aquifer is one of the most

productive sources of ground water in the U.S. Its water is hard
444

but of good quality. Wells yield large quantities of calcium

bicarbonate type of water. The Floridan aquifer is a thick

sequence of Tertiary limestone and dolomite. The Eocene Avon

Park Formation and Ocala Limestone are the thickest and most

productive units in the aquifer system.

Soils

The dominant soil orders in this MLRA are Ultisols,

Entisols, and Alfisols. The soils dominantly have a thermic soil

temperature regime, a udic soil moisture regime, and siliceous

mineralogy. Well drained and somewhat poorly drained

Paleudults (Blanton and Albany series) have thick sandy layers

over a loamy subsoil. Excessively drained and moderately well

drained Quartzipsamments (Alpin and Chipley series) are sandy

throughout. Well drained, sandy Hapludalfs (Archer series),

which have a clayey subsoil, and poorly drained, sandy

Alaquods (Mascotte and Leon series), which have a weakly

cemented layer, are less extensive in the area.

Biological Resources

This area supports open pine and oak vegetation. Longleaf

pine and turkey oak are the dominant trees. Several bluestem

species, Indiangrass, and several threeawn species dominate the

ground cover. Hairy panicum and many sedges are in scattered

areas. The MLRA also supports legumes and many annual forbs.

Some of the major wildlife species in this area are whitetailed deer, raccoon, skunk, opossum, rabbit, gray squirrel, fox

squirrel, turkey, bobwhite quail, and mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 9%

Grassland—private, 21%

Forest—private, 58%; Federal, 1%

Urban development—private, 8%

Water—private, 1%

Other—private, 2%

Most of this area is in wooded farms, and some large

holdings are used exclusively for forestry. Pulpwood and

lumber are the principal forest products. The cropland in the

area is used mainly for corn, peanuts, tobacco, soybeans,

vegetables, and melons. Some hay and feed grains are grown for

livestock.

The major resource concerns are maintenance of the content

of organic matter and productivity of the soils, management of

soil moisture, and management of animal waste. Conservation

practices on cropland generally include crop rotations, cover

crops, nutrient management, pest management, and irrigation

water management. 
445

Figure Q-1: Location of Land Resource Region Q.

Q—Pacific Basin Region

This region is made up of parts of four island groups in the

Pacific Ocean (fig. Q-1). The island groups include the Caroline

Islands (45 percent), Mariana Islands (41 percent), and Marshall

Islands (7 percent) in the North Pacific Ocean and American

Samoa (7 percent) in the South Pacific Ocean. This region

makes up 999 square miles (2,585 square kilometers).

The islands in this region (fig. Q-2) are typically high

volcanic islands (such as Pohnpei, Chuuk, Kosrae, and Palau),

coralline limestone islands (Tinian), or atolls (the Marshall

Islands and Ulithi Atoll). Many of the volcanic areas are steep,

some of them having slopes of more than 100 percent. Gently

rolling terrain with steep escarpments is common on the

coralline limestone islands. Some of the atoll islands have a

high elevation of only 6 feet (2 meters) above mean high tide,

in contrast to Pohnpei, where volcanic peaks reach an elevation

of more than 3,050 feet (930 meters), and Guam, which has

coralline limestone plateaus as high as 570 feet (175 meters).

The climate in this region is generally wet, hot, and humid.

The annual precipitation is 80 to 145 inches (2,030 to 3,685

millimeters) in most of the region. It decreases to the north,

away from the Equator, and is more than 200 inches (5,080

millimeters) in high-elevation areas. The wettest part of the

year is from December to March in American Samoa and from

July to November in the rest of the region. The driest part of the

year is from June to September in American Samoa and from

January or February to April or May in the rest of the region.

The average annual temperature is about 81 degrees F (27

degrees C), and all of this region is freeze-free. Daily

fluctuations in air temperature are typically wider than the

annual variability.

The total withdrawals of freshwater in this region are not

known. Based on area served, about 26 percent is from ground

water sources and 74 percent is from surface water sources.

Much of the surface water used in the region is from rainwater

catchments. Most of the water is used for domestic and public

drinking water supply.

The soils in this region are dominantly Mollisols, but

Entisols, Inceptisols, and Oxisols also are common. Andisols,

Alfisols, and Histosols are of more limited extent. The soils on

the Mariana Islands have an ustic soil moisture regime. Those

on the other islands in the region have a perudic or udic soil

moisture regime. All of the soils have an isohyperthermic soil
446 Major Land Resource Areas

Figure Q-2: An area of Land Resource Region Q.

temperature regime. They formed in residuum derived from

weathered or hard volcanic rock, coralline sand, or weathered

ash over coralline limestone.

About 90 percent of the land in this region is privately

owned. Tropical forest is the climax vegetation in most of the

region. The forests are used for ground water recharge,

agroforestry, woodland, and wildlife habitat. Many eroded

mountainous areas are in savanna because of periodic fires

during short dry periods. Mangrove forests ring some of the

islands protected by fringing or barrier reefs. Examples of these

islands are Pohnpei, Kosrae, Chuuk, Yap, and Palau.

The coral reefs and beaches support a variety of tourism

services, such as snorkeling, diving, sailing, sea kayaking,

hiking, and fishing. The tourism industry is significant on some

islands and has drawn many people into more concentrated

urban centers, especially on Guam and Palau. Golf courses and

high-rise hotels are common new additions to the landscape in

the Marianas. This shift began in the 1970s and continues. The

capital of the Federated States of Micronesia on the island of

Pohnpei draws people from the surrounding Caroline Islands in

search of economic opportunity, and the growth in population

has increased pressure on the local resources.

Most of the agriculture in this region is at the subsistence

level. Shifting cultivation is the norm. Many families have

gardens and maintain free-ranging pigs and poultry. Steep

slopes, low soil fertility, stoniness, and high acidity reduce the

variety of agriculture on most soils throughout the region.

High humidity and rainfall also are important management

concerns. Small but profitable commercial farms in the

Marianas produce cabbage, taro, sweet potatoes, cucumbers,

melons, papaya, and other fruits and vegetables for local

consumption. In most of the region, the population lives in the

coastal areas where commercial or subsistence fishing is an

important activity. 
of the United States 447

Figure 190-1: Location of MLRA 190 in Land Resource Region Q.

190—Stratovolcanoes of the Mariana

Islands

This area (shown in fig. 190-1) consists of Pagan, 26 percent;

Anatahan, 17 percent; Agrigan (or Agrihan), 16 percent;

Alamagan, 6 percent; Sarigan (or Sariguan), 3 percent; and five

smaller islands, 32 percent. It makes up about 71 square miles

(183 square kilometers). The area is north of Saipan, in the

western Pacific Ocean, about 1,600 miles (2,580 kilometers)

east of the Philippines and 3,800 miles (6,130 kilometers) westsouthwest of Hawaii. This island group is called the Northern

Islands of the Commonwealth of the Northern Mariana Islands

(CNMI). The islands are largely unpopulated. Pagan and

Sarigan have no permanent residents. Evacuations of Pagan in

1981 and Anatahan in 2003 were completed because of

volcanic activity. Civil Defense authorities have not allowed

residents to resettle these volcanically active islands.

Physiography

This area is in the Pacific Islands Province of the Pacific Rim

Area. The Northern Mariana Islands form the northern group of

the Mariana Arc archipelago. The Northern Islands are the

younger (Quaternary age) of two arcuate chains of volcanoes

that make up the archipelago. They formed at the subduction

zone between the Philippine and Pacific tectonic plates. The

islands are cone-shaped stratovolcanoes covered with volcanic

ash and cinder deposits on steep and very steep slopes. Many

steep slopes have eroded into deep gulches. Cliffs, steep slopes,

and boulder and cobble beaches characterize the coastlines.

There are small streams but no rivers in this area. Agrigan has

the highest elevation in the Mariana Arc, ranging from sea level

to 3,185 feet (970 meters).

Geology

Quaternary-age basalt and andesite lavas dominate on these

stratovolcanoes. Lava flows, volcanic ash, and cinder deposits

are common. The volcano on northern Pagan Island is

considered active, having last erupted in 1981. Anatahan Island

last erupted in April 2005. The United States Geological Survey

considers Maug a “volcano of concern” in this area and also

notes that hot spots offshore could become volcanoes in the

future.

Climate

The average annual precipitation in this area is about 80

inches (2,030 millimeters). Rainfall likely decreases northwards

and slightly increases with elevation. Climate data are scarce

for these remote islands. About two-thirds of the precipitation

falls between July and November. The average annual

temperature is about 79 degrees F (26 degrees C). The cooler

dry season is between January and May. It is enhanced by

persistent trade winds from the northeast and east-northeast.

Typhoons frequently pass close to the Northern Mariana

Islands. Typhoons are less common in the north than on Guam

in the MLRA to the south, which is severely impacted by large

storms about once every 8 years on average. This area is freezefree.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 100.0%; ground water, 0.0%

Livestock—surface water, 0.0%; ground water, 0.0%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 0.0%; ground water, 0.0%
448 Major Land Resource Areas

Only a few people live on these islands, and the total

quantity of withdrawals is not known. All of the water used in

this area is probably for domestic supply, and the local people

probably rely on surface water as their primary source of

drinking water. There are no perennial streams in the Northern

Islands. Two saline lakes are on Pagan. Also on Pagan, ground

water can be obtained from wells that reach sea level, as is

likely true in all of the Northern Islands. Hot springs and seeps

occur on the islands but are generally not of sufficient quality

or quantity to be considered water sources. Catchment water is

the best quality water on the islands, and it is used as drinking

water. Rainfall is nearly double the potential

evapotranspiration from July through November but only half

of the potential evapotranspiration from January into May.

Soils

The young age of volcanic deposits in this area has not

allowed for great differences among soils. The soils are

Andisols, Inceptisols, or Entisols. The soil moisture regime is

ustic in most areas but is aquic in depressions. All of the soils

have an isohyperthermic soil temperature regime. Most of the

soils are well drained and are on steep mountainsides or ridges.

Although some soils are very shallow or moderately deep to

bedrock or to cemented pyroclastic layers, most are very deep.

Haplustepts (Apilam series) and Haplustands (Plasanbola series)

are on ridge summits. Ustorthents (Shomushon series) and

Ustivitrands (Dekairu series) are on backslopes. Endoaquepts

(Benedicto series) are in broad basins in calderas, and

Ustivitrands (Songsong series) formed in alluvium and

mudflow deposits. Undifferentiated Entisols are on very young

landscapes, such as lava flows and talus slopes. Cinder land,

rock outcrops, and lava flows make up a considerable amount

of the surficial materials. The extent of the different soils and

miscellaneous areas has not been determined. A soil survey has

been completed only on the islands of Agrigan, Alamagan,

Anatahan, Pagan, and Sarigan. The total acreage of the

Northern Islands covered by soil surveys is 48.8 square miles

(126.4 square kilometers).

Biological Resources

Abandoned copra (coconut) plantations occur on lowelevation coastal sites. Areas above an elevation of 330 feet

(100 meters) are dominated by grassland, which supports

mainly swordgrass. Forest species are mixed tropical

hardwoods, including ironwood, pandanus, joga, coconut, and

beach hibiscus.

Large populations of feral cows, pigs, and goats are on some

of the islands. The endemic fruit bat and coconut crab are

locally important food sources (although the fruit bat is a

federally listed endangered species). A number of skinks and

geckos also are native to the Marianas. Several endemic bird

species, rufous fantail, the fairy tern, and the Vanikoro swiftlet,

also an endangered species, inhabit the islands. A wide range of

coral, anemones, shellfish, and reef and pelagic fish species are

within surrounding reef systems and open waters.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—private, 0.5%

Forest—private, 86.0%

Other—private, 13.0%: Federal, 0.5%

Ground water recharge and wildlife habitat are the main land

uses in this area. Asuncion, Farallon de Pajaros (Uracas),

Guguan, and Maug Islands are wildlife reserves for sea birds.

There are small areas of subsistence farming and agroforestry

on Agrigan, Anatahan, and Alamagan Islands. The main

subsistence crops are coconut, bananas, breadfruit, mango,

limes, taro, and yams. Copra plantations were once an

important land use.

The major resource concerns are the threat of lava flows and

ash deposition from volcanic eruptions on Pagan and Anatahan.

Feral animals contribute to erosion and changes in the plant

community. Multistory cropping is the main conservation

practice in this area. 

191—High Limestone Plateaus of the

Mariana Islands

This area (shown in fig. 191-1) consists of the northern half

of Guam (53 percent) and the islands of Saipan (18 percent),

Tinian (15 percent), Rota (13 percent), and Aguijan, or

Aguiguan (1 percent). This MLRA makes up about 256 square

miles (663 square kilometers). These islands are in the western

Pacific Ocean, roughly 1,600 miles (2,580 kilometers) east of

the Philippine Islands and approximately 3,730 miles (6,015

kilometers) west-southwest of Hawaii. This area includes the

Territory of Guam and the Commonwealth of the Northern

Mariana Islands (CNMI). Guam is the largest island of the

Mariana Islands and the economic hub of Micronesia.

Physiography

This area is in the Pacific Islands Province of the Pacific Rim

Area. The islands in the area are the southernmost islands of the

Mariana Arc archipelago. The topography ranges from nearly

level to gently sloping limestone plateaus to steep, complex

slopes in areas of volcanic bedrock. Precipitous cliffs along

limestone plateaus surround most of the northern half of Guam

and Saipan, as well as areas of Rota and Tinian. Cliffs, steep
of the United States 449

Figure 191-1: Location of MLRA 191 in Land Resource Region Q.

slopes, beaches, and reef flats characterize the coastlines. The

highest elevations are 1,637 feet (499 meters) on Rota, 1,555

feet (474 meters) on Saipan, 617 feet (188 meters) on Tinian,

and 828 feet (252 meters) in the northern part of Guam. There

are streams and a few small rivers in this area. Barrier and

fringing reefs are around the area.

Geology

The volcanic cores of these islands are the result of the

Pacific tectonic plate sliding under the Philippine tectonic

plate. Earthquakes are common. Reef and lagoon deposits

formed around the central volcanic cores of the islands. As a

result, limestone is the most extensive exposed bedrock. Most

of the limestone dates to the Pliocene and Pleistocene epochs.

The limestone plateaus and volcanic peaks were uplifted

through tectonic activity during the Tertiary and Quaternary

periods. Deeply weathered volcanic rock is exposed on ridges

and slopes.

Climate

The average annual rainfall is about 100 inches (2,540

millimeters) on northern Guam and 80 inches (2,030

millimeters) on Saipan, Tinian, Aguijan, and Rota. The rainy

season occurs from July through November, and the dry season

occurs from December through June. The dry season is

enhanced by persistent trade winds from the northeast. The

average annual temperature is 79 degrees F (26 degrees C).

Humidity is high throughout the year, averaging 76 percent.

Typhoons frequently pass close to the islands. The chance of a

typhoon severely impacting Guam is once in 8 years. The

chance of one severely impacting the CNMI islands is slightly

longer. Wind and rainfall are the most variable climatic factors

in this area, whereas temperature and humidity remain fairly

constant throughout the year. This area is freeze-free.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 45.0%; ground water, 53.9%

Livestock—surface water, 0.0%; ground water, 0.1%

Irrigation—surface water, 0.0%; ground water, 1.0%

Other—surface water, 0.0%; ground water, 0.0%

The total quantity of withdrawals is not known. About 55

percent is from ground water sources, and 45 percent is from

surface water sources. Except for springs around the periphery

of the shoreline and in areas of volcanic rocks, there are few

areas of fresh surface water. There are generally no streams or

rivers on the limestone bedrock. Some streams cut through the

limestone if they originate in volcanic landscapes upslope. Two

springs on Saipan and one on Rota are developed as a

freshwater supply. In 1986, these two islands used about 0.4

million gallons (1.5 million liters) of surface water per day.

Almost all of the people on Saipan and about 80 percent of

the population on Guam rely on ground water for domestic and

public supplies. Guam used approximately 33 million gallons

per day (125 million liters per day) for public supply in 1986.

About 78 percent was from ground water sources, and 21

percent was from surface water sources. Crops are irrigated by

the domestic water delivery system. Some farms and homes still

rely on rainwater catchment systems.

The principal aquifers in this area are the Tagpochau and

Mariana Limestone on Saipan and the Barrigada and Mariana

Limestone in northern Guam. The ground water in these

aquifers occurs as a thin lens of freshwater that floats on denser,

basal saltwater. The water from all these aquifers is very hard,

and its median level of total dissolved solids is about 850 and

600 parts per million (milligrams per liter), respectively, in the

two aquifers on Saipan and 308 and 574 parts per million

(milligrams per liter), respectively, in the two aquifers on Guam.
450 Major Land Resource Areas

During the dry season on Saipan, the freshwater lens becomes

overdrawn, resulting in saltwater intrusion. The two limestone

aquifers on Guam have been designated as “principal source

aquifers” by the Environmental Protection Agency, and Guam

has established special management practices to protect the

quality of the ground water. Increasing population in this

MLRA is putting more pressure on the ground water resources.

The increased pumping is creating more problems with

saltwater intrusion, and the increased extent of impervious

surfaces in urbanizing areas is decreasing the amount of

freshwater recharging the aquifers.

Soils

The soils in this MLRA are Alfisols, Andisols, Entisols,

Mollisols, or Oxisols. The dominant soil moisture regime is

ustic, and all of the soils have an isohyperthermic soil

temperature regime. The soils are very shallow to deep,

moderately well drained to somewhat excessively drained, and

fine textured or coarse textured and have amorphic, carbonatic,

ferruginous, gibbsitic, kaolinitic, mixed, oxidic, parasesquic, or

smectitic mineralogy. Almost all of the soils consist of highly

weathered clays and formed in limestone residuum. In some

areas volcanic ash has been added to the soils. All of the soil

orders occur on nearly level or rolling limestone plateaus. Most

of the soils overlying limestone are shallow. They include

Ustorthents (Guam series), Argiustolls (Banaderu series),

Haplustolls (Chinen series), and Haplustalfs (Pulantat series).

Shallow Haplustolls (Takpochao series) and Ustorthents

(Ritidian series) are on limestone escarpments and steep slopes.

Shallow Haplustands (Luta series) are on limestone plateaus on

Rota. The deep soils on limestone plateaus are Eutrustox

(Saipan series), Acrustox (Yigo series), and Haplustepts (Dandan

series). Deep alluvial soils are Endoaquepts (Inarajan series) on

valley bottoms and Paleustalfs (Chacha series) on limestone

plateaus. Ustipsamments (Shioya series) are on nearly level

coastal strands.

Biological Resources

The native vegetation in this area consists of mixed tropical

hardwoods, but the introduced tangantangan is the dominant

forest species in areas underlain by limestone. Other prominent

trees are gulos, Formosan koa, putting (or fishkill), and gaogao

(or tiger claw).

The only mammal endemic to the Mariana Islands is the

Marianas fruit bat. Other mammals, such as Sambar deer, pigs,

goats, and water buffalo, have been introduced and can be seen

in the wild. A number of skinks and geckos are native to the

Marianas. Several endemic bird species, rufous fantail, the fairy

tern, and the Vanikoro swiftlet, an endangered species, inhabit

the islands. The native bird populations on Guam have been

decimated through the accidental introduction of the brown

tree snake. A wide range of coral, anemones, and shellfish and

various reef and pelagic fish species are in the surrounding reef

systems and open waters.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 4.0%

Grassland—private, 9.0%; Federal, 11.0%

Forest—private, 46.0%; Federal, 17.0%

Urban development—private, 11.0%

Other—private, 2.0%

The U.S. Department of Defense has a significant impact on

these islands. A considerable amount of land has been

developed for airstrips, barracks, and fortifications, especially

on Guam and Tinian. Level areas are used for diverse

agricultural systems ranging from traditional subsistence

farming and gardening to modern commercial farming. The

important commercial crops are bananas, taro, eggplant, beans,

cucumbers, green peppers, tomatoes, many other vegetable and

fruit crops, and ornamentals. Urban development is occurring

on a significant acreage of these islands. Remote areas are used

for wildlife habitat, ground water recharge, and recreation.

The major soil resource concerns are water erosion and

maintenance of the productivity of the soils. Saltwater intrusion

into the fresh ground water lens used for domestic purposes also

is a concern, especially on Saipan. Conservation practices on

cropland generally include contour tillage and cover crops. In

northern Guam, no-till, strip-till, and mulching are common

conservation practices. 

192—Volcanic Highlands of the Mariana

Islands

This area is entirely in southern Guam (fig. 192-1). It makes

up about 78 square miles (202 square kilometers), or about 37

percent of Guam. The Territory of Guam is in the western

Pacific Ocean, about 1,600 miles (2,580 kilometers) east of the

Philippine Islands and about 3,800 miles (6,130 kilometers)

west-southwest of Hawaii. Guam is the largest island of the

Mariana Islands and the economic hub of Micronesia.

Physiography

This area is in the Pacific Islands Province of the Pacific Rim

Area. Guam is the largest and southernmost island of the

Mariana Arc archipelago. The interior of south Guam has steep

or very steep mountains deeply dissected by numerous streams

and some rivers. The windward east side of the area consists of

nearly level to moderately sloping plateaus that are highly

dissected by streams. The highest elevation in Guam, 1,336 feet
of the United States 451

Figure 192-1: Location of MLRA 192 in Land Resource Region Q.

(407 meters), is on a north- to south-trending ridge on the

leeward west side of the area. Cliffs, gentle to steep slopes,

beaches, and reef flats characterize the shoreline. Barrier and

fringing reef occurs around the area. More than 40 rivers and

streams form the drainage pattern in the area, and the Fena

Reservoir is near the center of the area.

Geology

South Guam consists primarily of deeply weathered volcanic

rock from an uplifted submarine volcano. This volcanic origin

is linked to the tectonic subduction of the Pacific Plate under

the Philippine Plate. Movement along the plate boundary

results in frequent earthquakes. The volcanic material is

primarily andesite and basalt reworked as tuff, tuff breccia,

tuffaceous sandstone, shale, and volcanic conglomerate formed

during the Oligocene and Miocene epochs. Areas of limestone

are along the southeast coast and on the tops of ridges in some

of the highest mountains.

Climate

The average annual rainfall ranges from about 85 to 100

inches (2,160 to 2,540 millimeters) in the northern half of this

MLRA and from about 95 to 118 inches (2,415 to 2,995

millimeters) in the southern half. The average annual

temperature is 79 degrees F (26 degrees C). The primary seasons

in the area are the dry season, from January through April, and

the rainy season, from July through November. Trade winds are

persistent during the dry season. Relative humidity is generally

high, averaging 76 percent. Variations in temperature and

humidity are small throughout the year. Typhoons frequently

pass close to Guam. The chance of a typhoon severely

impacting the island is once in 8 years. This area is freeze-free.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 100.0%; ground water, 0.0%

Livestock—surface water, 0.0%; ground water, 0.0%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 0.0%; ground water, 0.0%

The total quantity of withdrawals is not known. All of the

water used in this area is from surface water sources. Many

rivers and streams on the volcanic bedrock provide abundant,

good-quality surface water. Municipal water is stored in the

Fena Reservoir, which supplied approximately 7 to 9 million

gallons per day (25 to 35 million liters per day) to the U.S.

Naval Station in 1986. The Ugum River is a source of domestic

water. The water in some small ponds is used for irrigating

crops. Irrigation water also is obtained from the domestic water

delivery system. In addition to the Mariana and Barrigada

limestone aquifers described in MLRA 191, the Umatac and

Alutom formations are two volcanic rock aquifers that provide

some good-quality water for domestic use in southern Guam.

Some domestic water is pumped from sedimentary material in

the northwest corner of the area, along the coast.

Soils

The soils in this MLRA are Alfisols, Inceptisols, Mollisols,

or Oxisols. The dominant soil moisture regime is ustic, and all

of the soils have an isohyperthermic soil temperature regime.

The soils are shallow to deep, well drained to somewhat poorly

drained, and fine textured. Most of the MLRA is mapped as a

complex of Haplustox (Akina series) and Haplustolls (Agfayan

series). These soils, along with Haplustalfs (Atate series) and

Haplustepts (Sasalaguan and Togcha series), are on moderately

sloping to steep uplands. Endoaquepts (Inarajan series) and

Haplustepts (Ylig series) are on broad valley bottoms and
452 Major Land Resource Areas

Figure 193-1: Location of MLRA 193 in Land Resource Region Q.

coastal lowlands. Ustipsamments (Shioya series) are in beach

areas.

Biological Resources

This area is a mosaic of savanna grassland and patches of

forest. Except for remnants of a forest plant community in the

wetter gulches and river valleys, the native vegetation has been

largely replaced by grasses through repeated burning. The

grasses commonly are tall swordgrass and foxtail. The bottoms

of ravines and hillside springs are filled with coarse reeds,

karriso, and neti, which are adapted to wet soils. Forests,

occurring dominantly in ravines and on valley bottoms but also

on some hillsides, support pago (or beach hibiscus), kafu (or

pandanus or screw pine), and ahgao (or false elder).

The only mammal endemic to the Mariana Islands is the

Marianas fruit bat. Other mammals, such as Sambar deer, pigs,

goats, and water buffalo, have been introduced and can be seen

in the wild. A number of skinks and geckos are native to the

Marianas. Several endemic bird species, rufous fantail, the fairy

tern, and the Vanikoro swiftlet, an endangered species, inhabit

the islands. The native bird populations on Guam have been

decimated through the accidental introduction of the brown

tree snake. A wide range of coral, anemones, and shellfish and

various reef and pelagic fish species are in the surrounding reef

systems and open waters.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 1.5%; Federal, 0.5%

Grassland—private, 5.5%; Federal, 10.5%

Forest—private, 35.0%; Federal, 21.5%

Urban development—private, 18.0%; Federal, 1.5%

Water—private, 0.5%; Federal, 0.5%

Other—private, 4.5%; Federal, 0.5%

This MLRA is dominantly undeveloped grassland and forest

used for drinking water supply and wildlife habitat. Small truck

farms operate on valley bottoms and gently sloping uplands.

The main crops are bananas, taro, eggplant, beans, cucumbers,

green peppers, many other vegetable crops, and ornamentals.

The U.S. Department of Defense manages the Fena Reservoir.

Urban development is occurring primarily around the coastline.

The major soil resource management concern is water

erosion. Excessive erosion has led to the formation of badlands

that are difficult to revegetate. Excessive sediment overloads

the filtration capacity of the domestic water supply system and

causes periodic water delivery shutdowns during prolonged

periods of rainfall. Siltation of the adjacent coral reefs

adversely affects fisheries. Curbing human-induced grassland

fires and revegetating bare areas are additional resource

management concerns.

The most common conservation practices are contour

farming, strip-till or no-till, mulching, hillside ditches, terraces,

and grassed waterways on uplands and strip-till or no-till,

riparian forest buffers, filter strips, and field borders on the

wetter lowlands. 

193—Volcanic Islands of Western

Micronesia

This area includes most of the Palau (77 percent) and Yap

(23 percent) Islands in the western Caroline Islands group (fig.

193-1). It makes up about 196 square miles (508 square

kilometers). The Palau Islands are about 4,600 miles (7,420

kilometers) west-southwest of Hawaii and about 560 miles (905

kilometers) east of the southern Philippine Islands. The Yap

Islands are approximately 290 miles (465 kilometers) northeast

of Palau. The islands of Babeldaob, Koror, Malakal, and

Arakabesan are in the northern part of the Republic of Palau.

The Yap islands are in the western part of the Federated States

of Micronesia (FSM).

Physiography

This area is in the Pacific Islands Province of the Pacific Rim

Area. It is characterized by uplands underlain by volcanic and

metamorphic rocks. The Palau Islands range from level to very

steep and are characterized by deep, dendritic drainageways and

generally rounded hills. Raised marine terraces are exposed in a

few areas. The Yap Islands range from nearly level on raised,

dissected benches of volcanic rocks to hilly and mountainous in

areas of metamorphic rocks. The highest elevation is about 794

feet (242 meters) on Palau and about 555 feet (169 meters) on
of the United States 453

Yap. Mangrove swamps, barrier reefs, and some fringing reefs

surround both of these island groups. Small streams and rivers

are in this area.

Geology

The Palau and Yap Islands are primarily of volcanic origin,

consisting of tuff and breccia derived from basalt and andesite.

Eocene, and probably Oligocene, eruptions were mainly

submarine. Tectonic forces subsequently uplifted the islands.

Schist, a metamorphic rock derived from volcanic rocks, is the

bedrock in about half of the main Yap Islands. Like the Mariana

Islands to the north, the islands in this MLRA formed on the

boundary where the Pacific tectonic plate is being subducted

under the Philippine tectonic plate. Scattered marine terraces

and raised coral formations are mainly in coastal areas. Bauxite

was mined on volcanic rocks on Babeldaob in the 1920s and

1930s.

Climate

The average annual rainfall in this area is 122 to 145 inches

(3,100 to 3,685 millimeters). This MLRA is in the intertropical

convergence zone. This zone is an area of low pressure where

the Northeast Trade Winds meet the Southeast Trade Winds near

the Equator. As these winds converge, moist air is forced upward

and thunderstorms and heavy rainfall occur. In this area, the

rain intensifies with increased solar heating during the summer

and diminishes as the sun moves farther from the earth. The

driest season is from February through April. The average

annual temperature is 81 degrees F (27 degrees C). Humidity

averages about 90 percent at night and 75 to 80 percent during

the day. Typhoons are not common in this area. The area is

freeze-free.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 99.5%; ground water, 0.5%

Livestock—surface water, 0.0%; ground water, 0.0%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 0.0%; ground water, 0.0%

The total quantity of withdrawals is not known. Almost all of

the water used in this area is for domestic supply, and its source

is perennial streams. Some areas on both island groups use

water catchment systems. Crops are not typically irrigated. The

Ngerikiil Watershed provides most of the drinking water for

approximately 75 percent of the people of Palau. The island of

Babeldaob has 16 watersheds that supply continuous surface

water for the potable water needs of that island. About 70

percent of the rain falling on the island runs off to the ocean. In

the past, test wells were drilled in the fractured volcanic rocks

on the islands and ground water was obtained. The high levels

of iron and manganese in the water, however, created a

favorable environment for anaerobic bacteria. The bacteria

caused blockages in the pumps, so the wells did not yield water

for long. Shallow wells in bedrock that are probably drawing

water from surface sources provide some domestic water in this

area.

Soils

Most of the volcanic soils on uplands in this MLRA are

Oxisols, but some are Ultisols or Inceptisols. Alfisols and

Mollisols are in areas underlain by schist bedrock. Histosols,

Inceptisols, and Entisols are in low areas and coastal areas. The

dominant soil moisture regimes are perudic, udic, and aquic,

and the area is characterized by an isohyperthermic soil

temperature regime. The soils generally are moderately deep to

very deep, poorly drained to somewhat excessively drained,

and fine textured. Hapludalfs (Gitam and Rumung series) and

Argiudolls (Weloy series) are in areas underlain by schist. They

are somewhat poorly drained to well drained soils on nearly

level to very steep uplands and plains. The soils on volcanic

uplands include well drained Acroperox (Ngardok series),

Eutroperox (Yap series), Haploperox (Aimeliik, Palau, and

Gagil series), and Kandiperox (Babelthuap series).

Haplosaprists (Mesei series) are on wet freshwater bottom land,

and Sulfihemists (Ilachetomel and Ngerungor series) are very

poorly drained, organic soils in the coastal intertidal areas.

Dystrudepts are in somewhat poorly drained areas on bottom

land (Ngersuul and Sonahnpil series) and in well drained areas

on uplands (Ollei series). Endoaquepts (Dechel series) are

important agricultural soils on bottom land. The soils on

marine terraces include Haploperox (Ngatpang series) and

Kandiperox (Tabecheding series).

Biological Resources

The native vegetation in this area consists of tropical

hardwood trees and savanna grasses. The mountainous areas

support tropical hardwoods. The upland forest in Palau is

considered one of the most diverse forests in Micronesia.

Because of the different languages spoken on the individual

islands, there are numerous common names for the many plant

species in this area. As a result, scientific names for plants are

given in this paragraph. The common tree species in the

uplands are Campnosperma brevipetiolata, Parinari

corymbosa, Alphitonia carolinensis, and Rhus taitensis. Open

savanna on Babeldaob and the Yap Islands is common and is

thought to be the result of human activity, such as wildfire and

land clearing. Pandanus species may form a scattered overstory
454 Major Land Resource Areas

Figure 194-1: Location of MLRA 194 in Land Resource Region Q.

with grasses (Ischaemum species and Miscanthus floridulus).

Some degraded savanna is dominated by the fern Gleichenia

linearis. Savanna also has a component of shrubs, including

Wikstroemia elliptica, Melastroma malabathricum, and

Decaspermum species. Swamp forest, which is inundated with

fresh or slightly brackish water, is characterized by Hibiscus

tiliaceus, Horsfeldia amklaal, and Cynometra ramiflora.

Mangrove forests occupy most of the coastal intertidal

wetlands and are dominantly Sonneratia alba and Rhizophora

mucronata toward the sea and Lumnitzera littorea and

Xylocarpus granatum on the landward side of the mangroves.

The surrounding reef systems and open waters have a wide

range of coral, anemones, shellfish, and other marine and

pelagic fish species.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 11.0%

Grassland—private, 11.0%

Forest—private, 72.0%

Urban development—private, 4.5%

Water—private, 1.0%

Other—private, 0.5%

Forest, grassland, and agroforestry dominate the current land

uses. Valley bottoms and low-lying areas along the coast are the

most productive agricultural lands. Traditional agroforestry

systems are dominant, especially on Yap. Small commercial

farms growing truck crops are on uplands and bottom lands on

Babeldaob. Coconut, breadfruit, betel nut, papaya, bananas,

cassava, and taro are the principal crops.

The major soil resource concern is maintaining soil quality

and productivity in very infertile soils with a thin topsoil.

Preserving the quality of drinking water in southern Babeldaob

also is a major concern. 

194—Low Limestone Islands of Western

Micronesia

This area includes hundreds of islands in the southern part of

the Palau archipelago in the Western Caroline Islands group

(fig. 194-1). The area makes up about 27 square miles (70

square kilometers). The Palau Islands are about 3,830 miles

(6,180 kilometers) west-southwest of Hawaii and about 450

miles (725 kilometers) east of the southern Philippine Islands.

The main islands in this MLRA are Peleliu and Angaur, which

are 55 miles (90 kilometers) and 69 miles (110 kilometers),

respectively, southwest of the capital Koror. Over 350 smaller

Rock Islands are between Koror and Peleliu.

Physiography

This area is in the Pacific Islands Province of the Pacific Rim

Area. It is characterized by low, raised coralline limestone

islands. Broad areas of Angaur and Peleliu are nearly flat and

have an elevation of 15 to 30 feet (5 to 10 meters). Prominent

ridges of rugged limestone are as much as 262 feet (80 meters)

above sea level. North of these islands lies a maze of large and

small, extremely steep and rugged limestone islands, referred to

as the Rock Islands. There are no streams or rivers in this area,

but barrier and fringing reefs surround the islands.

Geology

The islands in this area consist of uplifted limestone.

Phosphate deposits were once mined on Angaur and Peleliu.

Climate

The average annual rainfall in this area is 148 inches (3,760

millimeters). This MLRA is in the intertropical convergence

zone. This zone is an area of low pressure where the Northeast

Trade Winds meet the Southeast Trade Winds near the Equator.

As these winds converge, moist air is forced upward and heavy

rainfall occurs. In this area, the rain intensifies with increased

solar heating during the summer. The rainiest months are June,

July, and August. The driest season is February through April.

The average annual temperature is 81 degrees F (27 degrees C).

Humidity averages about 90 percent at night and 75 to 80
of the United States 455

percent during the day. Typhoons are not common in this area.

The area is freeze-free.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 50.0%; ground water, 50.0%

Livestock—surface water, 0.0%; ground water, 0.0%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 0.0%; ground water, 0.0%

The total quantity of withdrawals is not known. About 50

percent is from ground water sources, and 50 percent is from

surface water sources. The islands are too small to have an

adequate supply of fresh ground water. Wells provide mostly

brackish water on Peleliu and Angaur. Catchment water is used

for domestic purposes. Crops are not irrigated.

Soils

This MLRA is characterized by uplands underlain by coral

bedrock. Most of the soils on uplands are Mollisols that formed

in limestone residuum. Histosols are of lesser extent in the areas

underlain by limestone. Entisols formed in wind- and waterdeposited coral sand in low-lying coastal areas. The dominant

soil moisture regimes are perudic and udic, and the area is

characterized by an isohyperthermic soil temperature regime.

The soils generally are shallow, well drained, and fine textured.

Well drained Haprendolls (Peleliu series) and Udifolists

(proposed Chelbacheb series) formed in residuum and are

interspersed with rock outcrop on nearly level to very steep

uplands. Udipsamments (Ngedebus series) formed in wind- and

water-deposited sand in coastal areas. The total area of the

MLRA that is covered by soil surveys is about 56 percent, or 15

square miles (39 square kilometers).

Biological Resources

The biological resources in this area include forests and

fisheries. The area supports a diverse forest community.

Because of the different languages spoken on the individual

islands, there are numerous common names for the many plant

species in this area. As a result, scientific names for plants are

given in this paragraph. Some of the more common species are

Gulubia palauensis, Ptychosperma palauensis, Semecarpus

venenosus, Intsia bijuga, Psychotria species, Premna

obtusifolia, Cordia species, Clerodendrum inerme, Pandanus

species, Dracaena multiflora, and Bikkia palauensis.

Mangrove forest occurs in protected areas on Angaur and

Peleliu. It includes Rhizophora apiculata, Bruguiera

gymnorhiza, and Ceriops tagal.

The common bird species are the fruit dove, Micronesian

pigeon, collared kingfisher, white tern, black noddy, brown

noddy, and the tropic bird. The only native mammals are

insectivorous bats and fruit bats. Macaque monkeys are an

introduced species on Angaur. Saltwater crocodiles inhabit

mangrove swamps. The surrounding reef systems and open

waters have a wide range of coral, anemones, shellfish, and

other marine and pelagic fish species.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 2.5%

Forest—private, 87.0%

Urban development—private, 7.5%

Other—private, 3.0%

Most of this MLRA is a tropical hardwood forest. Low-lying

areas along the coast of Angaur and Peleliu are the most

productive agricultural lands. Coconut, cassava, breadfruit,

betel nut, papaya, bananas, and taro are the principal crops.

Small areas of urban land are near the coast. Deep pits and

surface scars remain in areas that formerly were mined for

phosphate.

The major soil resource concern is maintaining soil quality.

Water erosion is not a problem. Measures that curb the spread of

invasive species and preserve the quality of the forests and

marine life are needed because this area is heavily used for

ecotourism. Developing a supply of quality drinking water is a

major concern. The most common conservation practices are

multistory cropping, mulching, hillside ditches, contour

farming, and cover crops. 

195—Volcanic Islands of Central and

Eastern Micronesia

This area includes the islands of Pohnpei (59 percent) and

Kosrae (19 percent) and the Chuuk Islands (22 percent) in the

eastern Caroline Islands group (fig. 195-1). The area makes up

about 224 square miles (580 square kilometers). The Chuuk

Islands are approximately 2,100 miles (3,380 kilometers) southsoutheast of Tokyo, Japan, and 3,500 miles (5,630 kilometers)

southwest of Honolulu, Hawaii. Pohnpei is approximately 440

miles (710 kilometers) east of Chuuk, and Kosrae is

approximately 360 miles (580 kilometers) east-southeast of

Pohnpei. The States of Pohnpei (Ponape), Chuuk (Truk), and

Kosrae (Kosaie) are in the Federated States of Micronesia

(FSM).
456 Major Land Resource Areas

Figure 195-1: Location of MLRA 195 in Land Resource Region Q.

Physiography

This area is in the Pacific Islands Province of the Pacific Rim

Area. It consists of dozens of high volcanic islands and low

islands and atolls consisting of coral. The high volcanic islands

are steep and very steep, highly dissected mountains. Only

about a third of the area of most of the islands consists of

rolling hills, alluvial coastal plains, and mangrove swamps that

surround the mountainous areas. Coastal plains account for

most of the relatively flat ground. Elevations range from sea

level to about 1,444 feet (440 meters) in Chuuk, 2,625 feet (800

meters) in Pohnpei, and 2,077 feet (633 meters) in Kosrae.

Fringing and barrier coral reefs surround these islands. The area

has streams and small rivers.

Geology

The high islands are derived from Tertiary-age, basic

igneous rock, mainly basalt, andesite, and trachyte lava flows

and dikes. Geomorphic development suggests that Chuuk is the

oldest of the major islands. It is the most eroded, and drowned

river valleys attest to recent subsidence. To the east are the

younger islands of Pohnpei and Kosrae, which also are highly

eroded.

Climate

The climate in this area is characterized by high rainfall,

high temperatures, and high humidity. The average annual

rainfall generally ranges from about 145 to 225 inches (3,685 to

5,715 millimeters) but is estimated to be as high as 295 inches

(7,495 millimeters) in the highest mountains. January through

March is the driest season. Northeasterly trade winds affect the

weather from November to June. The islands are frequently

under the influence of the intertropical convergence zone

between July and November, when moist southerly winds and

tropical disturbances are most frequent and when the humidity

is often very high. The average annual temperature is 81

degrees F (27 degrees C). Variations in temperature are very

minimal throughout the year. Typhoons are not common in this

area. The area is freeze-free.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 85.0%; ground water, 15.0%

Livestock—surface water, 0.0%; ground water, 0.0%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 0.0%; ground water, 0.0%

The total quantity of withdrawals is not known. About 15

percent is from ground water sources, and 85 percent is from

surface water sources. Domestic water is supplied by perennial

streams and rivers. In some areas water catchment systems

provide water for domestic use. Crops typically are not

irrigated. Wells tap the freshwater in joints and fractures in the

volcanic rocks or solution openings in the limestone or coral

deposits that have been raised above sea level.

Soils

Most of the soils on volcanic uplands are Inceptisols or

Oxisols, whereas the soils on bottom land are Entisols or

Histosols. The dominant soil moisture regime is perudic, and

the soil temperature regime is isohyperthermic. The soils are

dominantly shallow to very deep and are well drained to very

poorly drained. The soils on uplands are mostly fine textured

and have mixed or oxidic mineralogy. The soils on bottom land

generally are sandy and have carbonatic mineralogy. The soils

on volcanic uplands are nearly level to very steep, well drained

Dystrudepts (Dolen, Dolekei, Fomseng, Finol, and Sonahnpil

series), Acroperox (Rakied, Wahrekdam, and Umpump series),

and Hapludalfs (Tolonier series) and poorly drained

Endoaquepts (Inkosr and Nansepsep series). The soils on

bottom land and in coastal areas are nearly level, somewhat

poorly drained to excessively drained Udipsamments (Dublon

and Ngedebus series); steep, well drained Udorthents (Oatuu

series); and nearly level, poorly drained Psammaquents (Insak

series), Sulfaquents (Naniak series), Sulfihemists (Ngerungor

and Chia series), and Haplohemists (Mesei variant). There are

19 high volcanic islands within Chuuk Lagoon, but only the 9

largest islands were included in a soil survey.

Biological Resources

This area generally is forested, but it includes a few small

savannas, fern lands, and cleared and cultivated areas in the

lowlands and on mid-mountain slopes. Tropical palms and

broadleaf trees are the dominant plants in the mountain forests

on steep slopes. The most common trees are campnosperma,

eucalyptus, Honduras mahogany, teak, pandanus, and

mangrove. Agroforestry consists of a canopy layer of broadleaf

tree species, such as breadfruit and mango, as well as coconut

and pandanus cultivars, and a lower layer of bananas, kava,

cassava, medicinals, and other home-garden shrubs and herb
of the United States 457

plants. Mangrove forests make up most of the coastal intertidal

wetlands.

The most common birds in the area are doves, pigeons,

kingfishers, swiftlets, terns, herons, gulls, petrels, tropic birds,

and frigate birds. The only native mammals are fruit bats. The

surrounding reef systems and open waters have a wide range of

coral, anemones, shellfish, and reef and pelagic fish species.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 33.5%

Grassland—private, 1.5%

Forest—private, 62.0%

Urban development—private, 2.0%

Water—private, 0.5%

Other—private, 0.5%

Most of this MLRA is tropical hardwood forest and scattered

grassland. Most of the population lives on the coastal plains.

Subsistence farming occurs in river basins and on lowlands and

mid-mountain slopes. Valley bottoms and low-lying areas along

the coast are the most productive agricultural lands. Traditional

agroforestry systems dominate the landscape. Breadfruit, betel

nut, coconut, bananas, cassava, and taro are the principal crops.

Wildlife habitat and tourism are other important land uses.

The major soil resource concern is maintaining soil quality

and productivity in very infertile soils with a thin topsoil. The

most common conservation practices are multistory cropping,

forest stand improvement, tree planting, and mulching. 

Figure 196-1: Location of MLRA 196 in Land Resource Region Q.

196—Coral Atolls of Micronesia

This area consists primarily of coral atolls and some small,

low coral islands in the Republic of the Marshall Islands at the

eastern end of the Caroline Islands group (fig. 196-1). The area

makes up about 70 square miles (180 square kilometers). It is

roughly 2,300 miles (3,700 kilometers) southwest of Hawaii.

The 29 atolls made up of 1,225 islands in the Marshall Islands

are scattered over 502,000 square miles (1.3 million square

kilometers) between 4 and 14 degrees north latitude and 160

and 173 degrees east longitude.

Physiography

This MLRA is in the Pacific Islands Province of the Pacific

Rim Area. It consists of more than 1,000 low coral islands

within 29 atolls. The coral atolls consist of low, nearly level,

long, narrow islands. Most islets in the Marshall Islands are less

than 3,300 feet (1,005 meters) long and 1,650 feet (505 meters)

wide. The average island height is about 6 feet (2 meters), and

the highest elevation is about 20 feet (6 meters), on Likiep

Atoll. Fringing and barrier coral reefs surround these islands.

The area has no streams or rivers.

Geology

These islands originated as high volcanic islands, but over

time they have been lowered by erosion and tectonic

subsidence. Corals grew around the submerged islands, forming

atolls and shallow reefs.

Climate

The climate in this area is characterized by high rainfall,

high temperatures, and high humidity. The average annual

rainfall generally ranges from about 40 to 145 inches (1,015 to

3,685 millimeters). It decreases to the north, and the northern

atolls are prone to drought between December and May.

January, February, and March are generally the driest months in

the southern atolls, which receive 6 to 9 inches (150 to 230

millimeters) of rain during these months compared with a range

of 11 to 15 inches (280 to 380 millimeters) during the

remaining months. The average annual temperature is 81

degrees F (27 degrees C). Variations in temperature are very

minimal throughout the year. Typhoons are not common in this

area. The area is freeze-free.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 95.0%; ground water, 5.0%

Livestock—surface water, 0.0%; ground water, 0.0%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 0.0%; ground water, 0.0%

The total quantity of withdrawals is not known. About 5

percent is from ground water sources, and 95 percent is from

surface water sources. Domestic water is supplied by wells and

water catchment systems. Crops typically are not irrigated.

Wells tap freshwater in solution openings in the limestone or
458 Major Land Resource Areas

coral deposits where these deposits have been elevated above

sea level.

Soils

The soils in this MLRA are mainly Entisols, which are very

deep and somewhat excessively drained. The soil moisture

regime probably ranges from perudic to ustic, and all of the

mineral soils in the area have an isohyperthermic soil

temperature regime and carbonatic mineralogy. A soil survey

covers 6 square miles (15.5 square kilometers) on the islands of

Airik, Arno, Majuro, Mili, and Taroa of the Ratak chain. Cobbly

sands on the ocean side of the islands are Udorthents (Majuro

series), whereas noncobbly sands on the lagoon side are

Udipsamments (Ngedebus series). Ustipsamments and

Ustorthents (no series identified) may occur where the dry

season is more pronounced than in the area covered by the soil

survey. Manmade organic soils used for taro production are

probably Haplosaprists (Mesei series).

Biological Resources

These islands commonly have atoll-strand forest on the

fringes and agroforestry crops in the interior. Coconut trees

cover about 60 percent of the land area. Half-flower tree,

pandanus, ironwood, and hibiscus also are common.

Agroforestry consists of a canopy layer of useful tree species,

such as breadfruit, mango, and coconut, and a lower layer of

bananas and other garden plants.

 The most common birds are fruit doves, pigeons, and a

variety of sea birds. The area has no native mammals. The

surrounding reef systems and open waters have a wide range of

coral, anemones, shellfish, and other marine and pelagic fish

species.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 27.0%

Grassland—private, 9.5%

Forest—private, 33.5%

Urban development—private, 30.0%

Most of the cropland in this area is used for agroforestry, but

taro patches also are significant. Much of the land is covered by

roads, buildings, swamps, or beaches. The different islands have

small areas of subsistence agriculture and urban land.

The major soil resource concern is maintaining soil quality

and productivity in infertile soils with a thin topsoil.

Maintaining the content of organic matter in the soils is crucial

for sustainable agricultural productivity. Water conservation

and prevention of ground-water and lagoon pollution are

additional resource concerns. The most common conservation

practices are multistory cropping and mulching. 

Figure 197-1: Location of MLRA 197 in Land Resource Region Q.

197—Volcanic Islands of American Samoa

This area consists of the American Samoa islands of Tutuila,

Aunu`u, Ofu, Olosega, and Ta`u in the southern Pacific Ocean

(fig. 197-1). The islands that are not volcanic include Swains

Island and Rose Island. This MLRA makes up about 77 square

miles (199 square kilometers). It is approximately 2,300 miles

(3,710 kilometers) south-southwest of Hawaii and 4,150 miles

(6,695 kilometers) southwest of California.

Physiography

This area is in the Pacific Islands Province of the Pacific Rim

Area. The islands are characterized by extremely steep, highly

dissected volcanic mountains, small valleys, and a narrow

coastal plain leading into deep waters offshore. Landslide scars

are common on the steep mountainsides. More than half of this

area has slopes of more than 70 percent. The overall slope of

the landscape is derived from recent giant landslides and stream

erosion. Recent lava flows have built up a broad lava plain on

the south side of Tutuila, and there are a number of cinder cones

in this area. The highest elevation, 3,056 feet (931 meters), is

on Lata Mountain, on Ta`u. The second highest elevation,

2,142 feet (653 meters), is on Matafao Peak, on Tutuila.

Fringing and barrier coral reefs surround these islands. The area

has streams but no rivers.

Geology

This area consists of volcanic islands made up of

Pleistocene-age, basic igneous rocks, mainly basalt and lesser

amounts of andesite and trachyte. These rocks are weathered to

a considerable depth in some areas. Volcanic ash and cinders

have accumulated mostly on young, gently sloping surfaces.

Colluvium is common at the base of mountain slopes.

Climate

This area is characterized by a tropical maritime climate with

abundant rain and warm, humid days and nights. The average

annual precipitation is generally about 125 inches (3,175
of the United States 459

millimeters) but is more than 250 inches (6,350 millimeters) in

some areas. The amount of rainfall varies greatly over short

distances because of the effects of topography. The driest

months are June through September (winter), and the wettest

are December through March (summer). The average annual

temperature is 81 degrees F (27 degrees C). The relative

humidity ranges from 73 to 90 percent throughout the year. The

prevailing winds throughout the year are easterly trade winds.

They are less prevalent in summer than in winter. Typhoons

occasionally strike this area. The area is freeze-free.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 10.0%; ground water, 90.0%

Livestock—surface water, 0.0%; ground water, 0.0%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 0.0%; ground water, 0.0%

The total quantity of withdrawals is not known. About 90

percent is from ground water sources, and 10 percent is from

surface water sources. Fresh ground water is confined by dikes

at the higher elevations and is perched on saltwater at the lower

elevations. Ground water is pumped to large storage tanks, from

which it is distributed for domestic use. In 1986, about 36,000

people on Tutuila relied on ground water for their public and

industrial water supply. The Leone volcanic rock aquifer

supplied almost all of this water. The water is hard, but the

median level of total dissolved solids is only about 300 parts per

million (milligrams per liter). An increasing population and

increasing urbanization are putting pressure on the ground

water supply. Ground water recharge decreases as the area of

impervious surfaces increases, and heavy pumping is causing

some problems with saltwater intrusion. Also, fecal coliform

contamination has been detected in some wells on Tutuila.

In some areas water catchment systems from roofs into

cement tanks provide water for domestic use. Because of the

abundant rainfall, crops are seldom irrigated in this area. Some

perennial and intermittent streams are in the area.

Soils

Most of the soils on volcanic uplands are Mollisols and

Andisols that are shallow to very deep and generally are well

drained. The dominant soil moisture regime is perudic, and the

dominant soil temperature regime is isohyperthermic. The soils

generally are fine textured and have mixed, halloysitic, or

amorphic mineralogy. The soils on bottom land are Entisols

with sandy textures and carbonatic mineralogy and Histosols.

They range from shallow to very deep. Nearly level to very

steep, mostly well drained Hapludolls are on valley bottoms

(Leafu series) and talus slopes (Aua series) and are the dominant

soils on mountainsides (Fagasa series and Ofu and Sogi

variants). Steep, well drained Acroperox (Ofu series) also are on

mountainsides. Hapludands are mostly on gently sloping to

steep, young landscapes (Iliili, Puapua, and Sogi series) but

also occur on steep mountainsides (Olotania series). Gently

sloping to very steep, well drained Fulvudands (Pavaiai series)

and Hydrudands (Oloava series) are on uplands. Nearly level,

excessively drained Udipsamments (Ngedebus series), nearly

level, poorly drained Psammaquents (Insak series), nearly level,

excessively drained Udorthents (Ngedebus variant), and nearly

level, very poorly drained Haplosaprists (Mesei series) are on

bottom land and in coastal areas. Gently sloping, well drained

Udifolists (Tafuna series) are on young uplands upwind of most

sources of volcanic ash. The coral atolls of Rose and Swains

Islands are not included in a soil survey of the area.

Biological Resources

Rain forests cover most of this area. Tropical palms and

broadleaf trees are the dominant plants on steep slopes in the

mountain forests. The most common tree species are maota mea,

laga ́ali, asi, mamalava, and tava.

The most common birds in the forests are barn owls, tropic

bird, Samoan starlings, white-collared kingfisher, and the manycolored fruit dove. Sea birds include frigate bird, brown booby,

gray-backed tern, and white tern. The surrounding reef systems

and open waters have a wide range of coral, anemones,

shellfish, and other marine and pelagic fish species.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 31.0%

Grassland—private, 1.0%

Forest—private, 57.0%

Urban development—private, 10.5%

Other—private, 0.5%

Most of this MLRA is in tropical hardwood forests. The

interiors of the islands are virtually inaccessible because of very

steep mountainous terrain and dense vegetation. Most of the

population lives on the coastal plains and in valleys.

Subsistence farming occurs on lowlands and on mid-mountain

slopes. Valley bottoms and wet, low-lying areas are the most

productive lands for the staple crop of taro. Traditional

agroforestry systems dominate the agricultural landscape.

Agroforestry consists of a canopy layer of useful tree species,

such as breadfruit, coconut, and mango, and a lower layer of

bananas, kava, cassava, taro, and other garden plants. Coconut,

cassava, breadfruit, papaya, bananas, and taro are the principal

crops. Wildlife habitat is another important land use.

The major soil resource concern is water erosion on steep

slopes. The most common conservation practices are multistory

cropping, mulching, hillside ditches, contour farming, and

cover crops. 

461

Figure R-1: Location of Land Resource Region R.

R—Northeastern Forage and Forest

Region

This region (shown in fig. R-1) is in New York (31 percent),

Maine (27 percent), Pennsylvania (9 percent), Vermont (8

percent), New Hampshire (8 percent), Massachusetts (6 percent),

Ohio (5 percent), Connecticut (4 percent), New Jersey (1

percent), and Rhode Island (1 percent). It makes up 120,635

square miles (312,625 square kilometers).

Plateaus, plains, and mountains characterize this region. The

climate is generally cool and humid. The average annual

precipitation is generally 34 to 62 inches (865 to 1,575

millimeters). In most of the region, more than one-half of the

precipitation falls during the freeze-free period. The average

annual temperature is typically 40 to 48 degrees F (4 to 9

degrees C). The freeze-free period generally is 130 to 200 days,

but it ranges from 110 days in the higher mountains to 240

days in some areas along the Atlantic coast.

The total withdrawals of freshwater in this region average

about 19,100 million gallons per day (72,295 million liters per

day). About 93 percent is from surface water sources, and 7

percent is from ground water sources. About 78 percent of the

water is used for the timber industry and manufacturing and 21

percent for public supply.

The soils in this region are dominantly Entisols or

Spodosols. They commonly have a fragipan. Alfisols are less

extensive. They formed in limy parent material and have a

fragipan. The dominant suborders are Ochrepts and Orthods at

the higher elevations and Aqualfs, Aquepts, and Histosols on

lowlands and in depressions. The soils on flood plains

(Fluvents) are of small extent but are important for many uses.

The soils in the region dominantly have a frigid or mesic soil

temperature regime, a udic soil moisture regime, and mixed

mineralogy.

Most of the land in this region, especially the land in the

steeper areas, is forested, and 98 percent is privately owned.

Significant amounts of lumber and pulpwood are produced.
462 Major Land Resource Areas

Figure R-2: Potato fields in an area of Land Resource Region R.

Locally, Christmas trees and maple syrup are important forest

products. Forage and grains for dairy cattle are the principal

crops. In areas where markets, climate, and soils are favorable,

fruits, tobacco, potatoes (fig. R-2), and vegetables are important

crops. Wildlife habitat and recreation are important land uses.

Stoniness and steep slopes limit the use of many of the soils. 
of the United States 463

Figure 139-1: Location of MLRA 139 in Land Resource Region R.

139—Lake Erie Glaciated Plateau

This area (shown in fig. 139-1) is in Ohio (62 percent),

Pennsylvania (29 percent), and New York (9 percent). It makes

up about 10,715 square miles (27,770 square kilometers). It

includes the cities of Cleveland, Akron, Kent, Warren,

Youngstown, Massillon, Wooster, and Mansfield, Ohio;

Dunkirk, Fredonia, and Jamestown, New York; and Erie,

Sharon, and Newcastle, Pennsylvania. Interstates 76, 80, and 90

cross this area from east to west, and Interstates 71 and 77 cross

it from north to south. Interstate 79 crosses the northeastern and

eastern parts of the area. The Erie National Wildlife Refuge is in

the part of the area in Pennsylvania. Numerous State forests are

in the northeast corner of the area, in New York, and a number

of State parks are throughout the area. The Cuyahoga Valley

National Recreational Area is between Cleveland and Akron.

Physiography

Almost all of this area is in the Southern New York Section

of the Appalachian Plateaus Province of the Appalachian

Highlands. The southern edge of the area is in the Kanawha

Section of the same province and division. The western suburbs

of Cleveland, in the western tip of the area, are in the Till Plains

Section of the Central Lowland Province of the Interior Plains.

A narrow band along the shore of Lake Erie is in the Eastern

Lake Section of the same province and division. Most of this

MLRA is a gently rolling to strongly rolling, dissected

glaciated plateau. The narrow band along Lake Erie is fairly

flat. Stream valleys are narrow and are not deeply incised, but

the valley walls are typically steep. In some areas the

interfluves are broad and nearly level. Elevation ranges from

660 to 1,000 feet (200 to 305 meters), increasing gradually

from north to south. Local relief is about 7 to 50 feet (2 to 15

meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Southern Lake Erie (0411), 28 percent; Upper Ohio (0503), 25

percent; Allegheny (0501), 23 percent; Muskingum (0504), 16

percent; Eastern Lake Erie-Lake Erie (0412), 6 percent; and

Western Lake Erie (0410), 2 percent. The Cuyahoga and Grand

Rivers are designated as National Wild and Scenic Rivers in

northeastern Ohio. Most of the rivers in this MLRA flow north

to Lake Erie. The headwaters of the Ohio River are in the

northeast corner of this area, in Pennsylvania, and some of the

headwaters of the Muskingum River are in the central part of

the area, in Ohio.

Geology

The bedrock in this area consists mostly of alternating beds

of sandstone, siltstone, and shale of upper Devonian,

Mississippian, and Pennsylvanian age. Shale units are

dominant closer to the surface along Lake Erie and the western

edge of the area. The surface is mantled with glacial till,

outwash of unconsolidated sand and gravel, glacial lake

sediments, and stratified drift deposits (kames and eskers). The

outwash, lake sediments, and stratified drift deposits that fill

valleys are important sources of ground water. Younger stream

deposits cover the glacial deposits in some of the river valleys.

Climate

The average annual precipitation in this area is 34 to 50

inches (865 to 1,270 millimeters). Rainfall occurs as highintensity, convective thunderstorms during the summer. The

seasonal snowfall averages 40 inches (100 centimeters). The

average annual temperature is 44 to 51 degrees F (7 to 10

degrees C). The freeze-free period averages 180 days and ranges

from 145 to 215 days.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 8.1%; ground water, 1.1%

Livestock—surface water, 0.2%; ground water, 0.1%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 89.9%; ground water, 0.5%
464 Major Land Resource Areas

The total withdrawals average 6,190 million gallons per day

(23,430 million liters per day). This MLRA ranks tenth among

all of the MLRAs in total amount of water used. About 2

percent is from ground water sources, and 98 percent is from

surface water sources. Precipitation and perennial streams

provide an abundance of good-quality surface water. Lake Erie

and large reservoirs on perennial streams provide water for

public supply and industrial use in several of the large cities in

the area. On many farms, small constructed ponds provide water

for livestock and irrigation and are used for recreation.

Shallow and deep wells are the main sources of water for

domestic use and municipal supplies in this area. One source of

ground water is the glacial deposits in the valleys. The water

from these aquifers is hard or very hard and generally requires

softening. The level of total dissolved solids typically ranges

from 200 to 400 parts per million (milligrams per liter). This

good-quality water is susceptible to contamination from surface

activities because the aquifer is often directly recharged from

precipitation and runoff on the valley floors.

A second source of ground water in this area is the sandstone

bedrock. The water from this aquifer is generally very hard and

requires treatment prior to use. It is a calcium bicarbonate type

of water that has a median value of 322 parts per million

(milligrams per liter) total dissolved solids. At a depth of more

than 300 feet, this water is saline. Contamination of the water in

this bedrock aquifer is rare.

Soils

The dominant soil order in this MLRA is Alfisols. The soils

in the area dominantly have a mesic soil temperature regime, an

aquic or udic soil moisture regime, and mixed or illitic

mineralogy. They are very deep, well drained to poorly drained,

and loamy or clayey. Epiaqualfs (Mahoning series) formed in

till on till plains. Hapludalfs formed in outwash deposits on

outwash plains, terraces, kames, and beach ridges (Chili series)

and in till on till plains (Ellsworth series). Fragiudalfs formed in

till (Canfield and Rittman series) and loess over till (Wooster

series) on till plains and moraines. Fragiaqualfs (Frenchtown,

Platea, Ravenna, Sheffield, Venango, and Wadsworth series)

formed in till on till plains and moraines.

Biological Resources

This area supports mostly beech forest vegetation. American

beech, sugar maple, red oak, white ash, and white oak are the

dominant species. Other species include American basswood,

shagbark hickory, black cherry, and cucumbertree. American

beech and sugar maple are dominant on some poorly drained

flatlands. Mixed, mesophytic oak-sugar maple and oak forest

types occur in some areas.

Some of the major wildlife species in this area are whitetailed deer, cottontail, squirrel, pheasant, and quail.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 29%

Grassland—private, 6%

Forest—private, 36%; Federal, 1%

Urban development—private, 21%

Water—private, 2%

Other—private, 5%

About three-fourths of this area is in farms. Feed grains (corn,

soybeans, winter wheat, and oats) and forage (grass-legume hay,

tall fescue pasture, and alfalfa hay) for dairy cattle are the main

crops in the western part of the area. Similar crops are grown in

the eastern part, where there are many part-time farms and many

rural residences. The area has some cow-calf operations. Some

areas are used for potatoes or small fruit crops. A large amount

of the milk produced in the area is converted to cheese. The

areas of hardwood forest in the MLRA are mainly in farm

woodlots. Sawlogs for rough construction, firewood, and some

high-quality sawlogs for specialty uses are harvested from the

numerous farm woodlots. Some large holdings are used for

watershed protection.

The major soil resource concerns are sheet and rill erosion,

sedimentation by storm-water runoff, maintenance of the

content of organic matter and productivity of the soils, and

management of soil moisture. Conservation practices on

cropland generally include systems of crop residue

management (such as conservation tillage), winter cover crops,

grass-legume plantings, contour farming, irrigation water

management, compost facilities, nutrient management, manure

management, and pesticide management. Excluding livestock

from wetlands and watercourses and developing rotational

grazing systems help to control erosion and protect water

quality. Conservation practices that are important to

community development include critical site planting and

urban storm-water management. 

140—Glaciated Allegheny Plateau and

Catskill Mountains

This area (shown in fig. 140-1) is in New York (65 percent),

Pennsylvania (34 percent), and New Jersey (1 percent). It makes

up about 22,370 square miles (57,975 square kilometers). It

includes the cities of Binghamton, Johnson City, Endicott,

Elmira, and Corning, New York, and Carbondale, Scranton, and

Wilkes-Barre, Pennsylvania. Interstate 81 connects the cities of

Binghamton and Scranton, Interstate 84 crosses the southeast

corner of the area, Interstate 90 (the New York Thruway) crosses

the northern part, and Interstate 87 parallels the eastern border.
of the United States 465

Figure 140-1: Location of MLRA 140 in Land Resource Region R.

Numerous State forests and State parks are throughout this

MLRA. The Catskill Mountains are in the eastern part of this

area, in New York.

Physiography

This area is primarily in the Southern New York Section of

the Appalachian Plateaus Province of the Appalachian

Highlands. The east-central part is in the Catskill Section of the

same province and division. A small portion of the Allegheny

Mountain Section is in the south-central part of this MLRA, and

the southwest corner of the MLRA is in the Kanawha Section.

These two sections are in the Appalachian Plateaus Province of

the Appalachian Highlands. The southeast edge and a

fingerlike area protruding into the southeast corner of the

MLRA are in the Middle Section of the Valley and Ridge

Province of the Appalachian Highlands. The top of the

dissected plateau in this MLRA is broad and is nearly level to

moderately sloping. The narrow valleys have steep walls and

smooth floors. The Catskills in the east have steep slopes.

Elevation is typically 650 to 1,000 feet (200 to 305 meters) on

valley floors; 1,650 to 2,000 feet (505 to 610 meters) on the

plateau surface; and 3,600 feet (1,100 meters) or more in parts

of the Catskills.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Susquehanna (0205), 50 percent; Delaware (0204), 20 percent;

Upper Hudson (0202), 9 percent; Southwestern Lake Ontario

(0413), 8 percent; Southeastern Lake Ontario (0414), 5 percent;

Eastern Lake Erie-Lake Erie (0412), 4 percent; and Allegheny

(0501), 4 percent. This MLRA includes the headwaters of the

Susquehanna, Delaware, and Allegheny Rivers. The Genesee

River, in the southwestern part of this area, is one of the few

rivers in the area that flow north.

Geology

The bedrock in this area includes alternating shale and

sandstone beds of Devonian age. Some of the upper Devonian

layers have been eroded away in the part of the area in New

York. Glacial drift mantles the area. Significant deposits of

glacial outwash, consisting of unconsolidated sand and gravel,

fill most of the valley floors. Some glacial lake sediments and

ice-contact and stratified drift deposits occur in most of the

valleys. These deposits are the primary aquifers in this area.

Younger stream deposits cover some of the glacial deposits on

the valley floors.

Climate

The average annual precipitation in most of this area is 30 to

45 inches (760 to 1,145 millimeters). It is 45 to 64 inches

(1,145 to 1,625 millimeters) in small areas at the higher

elevations in the eastern part of the MLRA. Rainfall occurs as

high-intensity, convective thunderstorms during the summer,

but most of the precipitation in this area occurs as snow. The

average annual temperature is 40 to 50 degrees F (4 to 10

degrees C). The freeze-free period averages 165 days and ranges

from 130 to 200 days. The coldest temperatures and the shortest

freeze-free periods are in the high-elevation areas in the eastern

part of the MLRA.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 7.2%; ground water, 4.0%

Livestock—surface water, 0.1%; ground water, 0.4%

Irrigation—surface water, 0.3%; ground water, 0.0%

Other—surface water, 83.3%; ground water, 4.7%

The total withdrawals average 3,100 million gallons per day

(11,735 million liters per day). About 9 percent is from ground

water sources, and 91 percent is from surface water sources.

Precipitation and perennial streams and lakes provide an

abundance of good-quality surface water in this area. Soils that

have a fragipan are too wet in winter and spring for cultivation

and are deficient in moisture during much of the growing

season.

The primary source of ground water in this area is the glacial

outwash deposits in the valleys. The water in these deposits is

hard or very hard and may require softening. The average level

of total dissolved solids is about 200 parts per million

(milligrams per liter). This good-quality water is susceptible to

contamination from surface activities because the aquifer is

often directly recharged from precipitation and runoff on the
466 Major Land Resource Areas

valley floors. The valleys are the sites of the most intensive

land use activities in this hilly area.

A secondary source of ground water, primarily in the

southern half of the area, in Pennsylvania, is the sandstone and

shale aquifer. Water from this aquifer varies in quality,

depending on the source rocks. The water from dominantly

sandstone units is soft, and the water from the shale units

generally is hard and requires treatment prior to use. The water

from this aquifer is a calcium bicarbonate type that has about

300 parts per million (milligrams per liter) total dissolved

solids. Contamination from surface activities is rare.

Soils

The dominant soil order in this MLRA is Inceptisols. The

soils in the area dominantly have a mesic soil temperature

regime, an aquic or udic soil moisture regime, and mixed

mineralogy. They are shallow to very deep, well drained to

very poorly drained, and loamy or loamy-skeletal. Dystrudepts

(Arnot, Lordstown, and Oquaga series) formed in till on hills

and dissected plateaus. Fragiudepts (Bath, Lackawanna,

Mardin, Swartswood, Wellsboro, and Wurtsboro series) and

Fragiaquepts (Chippewa, Morris, Norwich, and Volusia

series) formed in till (dense till in some areas) on hills and

till plains.

Biological Resources

This area supports forest vegetation, particularly hardwood

species. Beech-birch-maple and elm-ash-red maple are the

potential forest types. The extent of oak species increases from

east to west, particularly in areas of shallow and dry soils. In

some areas conifers, such as white pine, are important. Aspen,

hemlock, northern white-cedar, and black ash grow on the

wetter soils. In some parts of the area, sugar maple has potential

economic significance.

Some of the major wildlife species in this area are whitetailed deer, cottontail, turkey, pheasant, and grouse.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 17%

Grassland—private, 10%

Forest—private, 60%; Federal, 1%

Urban development—private, 8%

Water—private, 2%

Other—private, 2%

A large acreage in this area is in second- and third-growth

forests of oak and northern hardwoods. Much of the area is in

farms. Hay, pasture, and some grain for dairy cattle are the

principal crops. Potatoes are an important crop on the top of the

plateau, and poultry, fruits, and truck crops are produced in

many of the narrow valleys. Abandoned or idle land, which is

common in the steeper areas, is reverting to grasses, weeds,

shrubs, and trees. Urban development is expanding in some

areas. The Catskills are used mainly for recreation.

The major soil resource concerns in this area are water

erosion, soil wetness, and maintenance of the content of

organic matter and productivity of the soils. Sedimentation

from nonpoint sources, such as agricultural and urban runoff,

also is a concern. Conservation practices on cropland generally

include conservation tillage, contour stripcropping, crop

rotations, crop residue management (mulch-till), cover crops,

diversions, and grassed waterways. Conservation practices on

forestland generally include forest stand improvement and

proper construction, use, and maintenance of skid trails, water

bars, access roads, and log landings. 

141—Tughill Plateau

This area is entirely in New York (fig. 141-1). It makes up

about 1,175 square miles (3,045 square kilometers). It has no

major towns or roads. This plateau lies between Lake Ontario

and the Adirondack Mountains. State highways and secondary

roads skirt the lowlands around the base of the plateau. The

area has numerous State forests, and the public trail system in

the area is used heavily by drivers of all-terrain vehicles and

snowmobiles.

Physiography

Most of this area is in the Mohawk Section of the

Appalachian Plateaus Province of the Appalachian Highlands.

The west and southwest third of the area is in the Eastern Lake

Section of the Central Lowland Province of the Interior Plains.

This MLRA is nearly level to gently sloping across the top of

the plateau and hilly to steep around the margins. Elevation

ranges from 980 feet (300 meters) along the lower margins to

1,970 feet (600 meters) at the top of the plateau. Local relief

generally is 15 to 80 feet (5 to 25 meters), but the bordering

lowlands are typically about 330 feet (100 meters) below the

top of the plateau.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Southeastern Lake Ontario (0414), 80 percent; Northeastern

Lake Ontario-Lake Ontario-St. Lawrence (0415), 15 percent;

and Upper Hudson (0202), 5 percent. Streams flow off the

plateau in several directions. The principal rivers in the area are

the Salmon and Mad Rivers and the East and West Branches of

the Fish River.

Geology

This plateau is underlain mostly by Ordovician-age

sandstones. The Queenston shale occurs in the southwest part
of the United States 467

Figure 141-1: Location of MLRA 141 in Land Resource Region R.

of the area, and the Oswego and Pulaski sandstone, siltstone,

and shale beds occur in the rest of the area. All of the area has a

thin mantle of glacial till. Some glacial lake sediments and

moraines occur in the southwest part of the area.

Climate

The average annual precipitation in most of this area is 45 to

63 inches (1,145 to 1,600 millimeters). It is 41 to 45 inches

(1,040 to 1,145 millimeters) around the lower margins of the

plateau. The precipitation is evenly distributed throughout the

year. Rainfall occurs as high-intensity, convective

thunderstorms during the summer. Lake-effect snowfall is heavy

from late in autumn to early in spring. In some areas the

seasonal snowfall is as much as 140 inches (355 centimeters).

The average annual temperature is 40 to 46 degrees F (4 to 8

degrees C). The freeze-free period averages 160 days and ranges

from 135 to 180 days. The lowest temperatures and the shortest

freeze-free periods are on the summit of the plateau.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 11.5%; ground water, 17.2%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 23.8%; ground water, 47.5%

The total withdrawals are about 0.4 million gallons per day

(1.5 million liters per day). About 65 percent is from ground

water sources, and 35 percent is from surface water sources.

Precipitation and perennial streams provide an abundance of

good-quality surface water. The area has few natural ponds or

lakes, and the water resources available in the area are little

used because of the lack of urban centers, mining, industry, or

suitable agricultural land. Dense fragipans in most of the soils

perch ground water for extended periods in winter and spring.

Shallow and deep wells supply water for domestic use and

for livestock, the two main uses of water in this area. Stratified

glacial drift is a source of ground water in the central and

southeastern parts of this MLRA. In nearly level areas

consisting mainly of glacial lake sediments, ground water is

close to the surface during part of the year. The water from this

aquifer is hard or very hard, but it typically has less than 150

parts per million (milligrams per liter) total dissolved solids.

A sandstone bedrock aquifer occurs under almost all of this

area. It has very hard water, but the median value of total

dissolved solids is only about 300 parts per million (milligrams

per liter). The water in this aquifer has the highest levels of

chloride of all the aquifers in this area. The median value of

100 parts per million (milligrams per liter), however, is well

below the drinking water standard of 250 parts per million

(milligrams per liter).

Soils

Most of the soils in this MLRA are Orthods or Aquods. They

have a frigid soil temperature regime, a udic or aquic soil

moisture regime, and mixed or isotic mineralogy. Many have a

fragipan. Most are very deep to bedrock. The soils are loamy or

sandy and have varying amounts of gravel. Surface stones and

boulders are common. The soils formed mostly in glacial till

derived primarily from acid sandstone. The till is compact and

dense in many places. Well drained and moderately well

drained Fragiorthods (Worth and Empeyville series) are in

undulating to sloping areas. Nearly level to gently sloping,

somewhat poorly drained Fragiaquods (Westbury series) are in

the lower areas. Very poorly drained Endoaquepts (Tughill

series) are extensive on flats and in depressions. Very poorly

drained Haplohemists (Rifle series) are in bogs in a few of the

large, deeper and wetter depressions. Somewhat excessively

drained and excessively drained Haplorthods (Colosse and

Adams series) that formed in sandy or gravelly outwash are

prominent locally but are of small extent in the MLRA.

Biological Resources

This area supports northern hardwoods. The beech-birchsugar maple forest type is of primary importance. Sugar maple

is of particular economic significance. The elm-ash-red maple

type also has potential in some parts of the area. Red spruce,

balsam fir, and white pine can be expected to occur in mixed

stands. Early succession vegetation includes highbush

blueberry, lowbush blueberry, and aspen-birch forest types. As

succession approaches climax, sugar maple, beech, and
468 Major Land Resource Areas

Figure 142-1: Location of MLRA 142 in Land Resource Region R.

hemlock increase in importance. Eastern hemlock, white

spruce, American elm, black ash, and red maple grow on the

wetter soils. A mixture of moss, Labrador tea, and fern occurs on

extremely wet, organic soils.

Some of the major wildlife species in this area are whitetailed deer, snowshoe hare, cottontail, and ruffed grouse.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 8%

Grassland—private, 6%

Forest—private, 79%

Urban development—private, 3%

Water—private, 2%

Other—private, 2%

Most of this area is forested with mixed hardwoods and

conifers. Part of the forestland is abandoned cropland that has

reverted to forest vegetation. Pulpwood, sawlogs, Christmas

trees, and maple syrup are the principal forest products. The

cropland in the area is used mainly for forage and some feed

grains grown for dairy cattle. A sizable acreage has reverted to

unproductive brush and weeds. A small acreage is used for

urban development.

The major soil resource concerns in this area are water

erosion, soil wetness, and maintenance of the content of

organic matter and productivity of the soils. Sedimentation

from nonpoint sources, such as agricultural and urban runoff,

also is a concern. Conservation practices on cropland generally

include conservation tillage, contour stripcropping, crop

rotations, crop residue management (mulch-till), cover crops,

diversions, and grassed waterways. Conservation practices on

forestland generally include forest stand improvement and

proper construction, use, and maintenance of skid trails, water

bars, access roads, and log landings. 

142—St. Lawrence-Champlain Plain

This area (shown in fig. 142-1) is in New York (73 percent)

and Vermont (27 percent). It makes up about 7,040 square miles

(18,240 square kilometers). Burlington, Vermont, and

Ogdensburg, Plattsburgh, and Watertown, New York, are

important cities in this area. The area is served by Interstates 81,

87, and 89, which run north and south. Fort Drum Military

Reservation is in the southwestern part of the area. Parts of the

MLRA are in Adirondack State Park. The St. Lawrence River

and the Canadian border form the north end of this area. The

area is bounded on the west by Lake Ontario, on the south by

the Adirondack Mountains, and on the east by the Green

Mountains. It surrounds Lake Champlain at the New YorkVermont border.

Physiography

The northern half of this area is in the Champlain Section of

the St. Lawrence Valley Province of the Appalachian Highlands.

Small areas in the northern part of the MLRA are in the

Adirondack Province of the same division. Most of the

southwest corner of the area is in the Eastern Lake Section of

the Central Lowland Province of the Interior Plains. A small

area in the southwest corner is in the Mohawk Section of the

Appalachian Plateaus Province of the Appalachian Highlands.

The southeastern extremities of the MLRA are in the Hudson

Valley Section of the Valley and Ridge Province and the Taconic

Section of the New England Province of the Appalachian

Highlands. This MLRA is a glaciated area of low relief

dominated by broad expanses of nearly level, sandy deltas and

shallow lacustrine basins or plains punctuated by low hills of

glacial till. Rivers and streams have cut relatively deep but

narrow valleys across the plain. Elevation ranges from 80 to

1,000 feet (25 to 305 meters), increasing gradually from the St.

Lawrence River southward and from Lake Champlain to the

east and west. Local relief generally is less than 30 feet (10

meters), but glacial till ridges, till plains, and some outwash

terraces rise 15 to 80 feet (5 to 25 meters) above the adjacent

plains.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Northeastern Lake Ontario-Lake Ontario-St. Lawrence (0415),

50 percent; Richelieu (0201), 47 percent; and Southeastern

Lake Ontario (0414), 3 percent. The St. Lawrence River and

Lake Champlain are important waterways in this area. Many

rivers drain across the area from the Adirondack Mountains to

the St. Lawrence River in the west and north and to Lake
of the United States 469

Champlain in the east. These rivers include the Moose, Black,

Beaver, Oswegatchie, Grass, Raquette, St. Regis, Saranac,

Ausable, and Bouquet Rivers.

Geology

This area has been glaciated, and a thin mantle of till covers

most of the bedrock. Extensive areas of sandy glacial outwash

and eolian deposits also occur. Some glacial lake sediments

have been deposited above glacial moraines. These deposits are

thickest in the valleys and thinnest on the ridges and

highlands. During the later stages of the Wisconsin glacial

period, seawater entered the Champlain Valley and deposited

marine sediments that were later covered by freshwater

sediments. The marine deposits are unique to the area.

Numerous bedrock outcrops occur in the western half of the

area. The bedrock is primarily the Stony Point shale on top of a

series of beds of limestone and dolomite of Ordovician age.

Below these rocks are the Cambrian Potsdam sandstone and

conglomerate. The limestone units and the Potsdam Sandstone

are major aquifers. Some quartzite layers are in the carbonate

rocks in the part of this area in northwestern Vermont.

Climate

The average annual precipitation in most of this area is 30 to

45 inches (760 to 1,145 millimeters). It is 45 to 60 inches

(1,145 to 1,525 millimeters) in the high-elevation areas in the

southern part of the area. The precipitation is evenly distributed

throughout the year. Most of the rainfall occurs as highintensity, convective thunderstorms during the summer.

Snowfall is heavy from late in autumn to early in spring. The

average annual temperature is 41 to 47 degrees F (5 to 9

degrees C). The freeze-free period averages 165 days and ranges

from 140 to 190 days. It is longest in a narrow belt around Lake

Champlain.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 10.0%; ground water, 0.8%

Livestock—surface water, 0.2%; ground water, 0.2%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 86.7%; ground water, 2.0%

The total withdrawals average 1,020 million gallons per day

(3,860 million liters per day). About 3 percent is from ground

water sources, and 97 percent is from surface water sources.

Precipitation and numerous perennial streams provide an

abundance of surface water. The St. Lawrence Seaway, which

forms the northern border of the area, and Lake Champlain, on

the eastern border, are important transportation arteries and are

used extensively for recreation. Industry is generally the largest

user of both surface and ground water in this area. The steep

terrain provides numerous opportunities for hydropower

facilities on rivers. Even though New York ranks third among

the States in the production of electricity from hydropower,

only 3 percent of the State’s needs are met by this power source.

The surface water in the area generally is of excellent quality.

Acid rain is a problem. The acidity removes metals, such as

aluminum, iron, and mercury, from soils, and these

contaminants enter the streams, lakes, and reservoirs and

eventually enter the food chain. Algae growth in Lake

Champlain is a local concern.

Ground water is abundant in this MLRA. Deep wells in the

stratified glacial drift yield moderate quantities of water for

domestic use. In nearly level areas consisting mainly of heavy

textured marine and lake sediments, ground water is close to the

surface during part of the year. The unconsolidated sand and

gravel in alluvial and glacial outwash deposits filling valley

floors is a significant aquifer in the part of this area in Vermont.

The water from this aquifer is hard or very hard, but it typically

has less than 150 parts per million (milligrams per liter) total

dissolved solids.

Two bedrock aquifers, a carbonate system and the Potsdam

sandstone, occur in the northwestern, north-central, and

northeastern parts of this MLRA. The water in the carbonate

aquifer is the hardest encountered in New York and Vermont. It

is the only water in the area that exceeds the national secondary

drinking water standard for total dissolved solids, 500 parts per

million (milligrams per liter). The Potsdam sandstone typically

lies beneath the carbonate aquifer, but both aquifers do not

always occur in a given area. The sandstone has very hard

water, but the median value of total dissolved solids is only

about 300 parts per million (milligrams per liter). The water in

the sandstone has the highest levels of chloride of all the

aquifers in this area. The median value of 100 parts per million

(milligrams per liter), however, is well below the drinking water

standard of 250 parts per million (milligrams per liter).

Soils

The dominant soil orders in this area are Alfisols, Inceptisols,

Spodosols, and Entisols. The soils in the area have a frigid or

mesic soil temperature regime, an aquic or udic soil moisture

regime, and mixed or isotic mineralogy. They are shallow to

very deep, excessively drained to very poorly drained, and

sandy to clayey. Hapludalfs (Hudson and Vergennes series),

Endoaqualfs (Niagara and Rhinebeck series), and Epiaqualfs

(Muskellunge series) formed in lacustrine sediments on lake

plains. Dystrudepts formed in till on uplands (Charlton series)

or on flood plains (Lovewell series). Epiaquepts (Malone series)

formed in till on uplands. Eutrudepts (Amenia series) formed in

dense till on uplands. Haplorthods and Udipsamments formed

in sandy glaciofluvial or lacustrine deposits on outwash plains,

lake plains, eskers, and terraces (Adams and Colton series,

examples of Haplorthods, and Plainfield series, an example of
470 Major Land Resource Areas

Figure 143-1: Location of MLRA 143 in Land Resource Region R.

Udipsamments); in till on hills, mountains, and plateaus

(Berkshire, Lyman, and Tunbridge series); and in loamy

sediments over dense till (Becket and Potsdam series).

Haplohumods (Rawsonville series) formed in till on hills,

mountains, and plateaus. Fragiorthods (Worth series) formed in

dense till on till plains. Cryofolists (Ricker series) formed in

organic material on mountains and hills.

Biological Resources

This area supports hardwoods. The beech-birch-sugar maple

forest type is the dominant climax forest type on uplands.

Associated with this type are basswood, American elm, maple

species, white ash, black cherry, and white pine. The aspenbirch type, earlier in succession, is economically important.

Such species as eastern hemlock, red maple, American elm, and

spruce are on wet soils.

Some of the major wildlife species in this area are whitetailed deer, red fox, raccoon, beaver, woodchuck, muskrat,

cottontail, ruffed grouse, and woodcock.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 21%

Grassland—private, 11%; Federal, 1%

Forest—private, 49%; Federal, 2%

Urban development—private, 5%

Water—private, 8%

Other—private, 3%

Most of this area is in forests or farms. The forests consist of

northern hardwoods and conifers. Sawlogs and pulpwood are

the main forest products. Christmas trees and maple syrup also

are produced throughout the area. Dairy operations and some

beef operations are common. Hay for dairy cattle is the

principal crop, but small grain and corn are grown for silage in

some areas. Potatoes are an important cash crop in some areas,

and a few apple orchards are on the slopes along Lake

Champlain, but the total acreage of these crops is small. Some

areas are used for urban development.

The major soil resource concerns on cropland are sheet, rill,

and gully erosion; the content of organic matter and

productivity of the soils; and surface compaction (resulting

primarily from harvesting crops under wet conditions). Some

erosion results from logging practices. Conservation practices

on cropland generally include conservation tillage, contour

stripcropping, crop rotations, crop residue management

(primarily mulch-till), cover crops, diversions, and grassed

waterways. Conservation practices on forestland generally

include forest stand improvement and proper construction, use,

and maintenance of skid trails, water bars, access roads, and log

landings. 

143—Northeastern Mountains

This area (shown in fig. 143-1) is in Maine (54 percent), New

York (25 percent), Vermont (12 percent), New Hampshire (7

percent), and Massachusetts (2 percent). It makes up about

36,840 square miles (95,465 square kilometers). This area is in

three parts, separated by other MLRAs. The western part is in

New York (primarily the Adirondack Mountains). The central

part is mainly in the Green Mountains in Vermont and the

Berkshires in Massachusetts. The eastern part is in the White

Mountains in New Hampshire and most of northern Maine.

There are no major cities in this mountainous MLRA. Interstate

95 cuts across the eastern part of the area, in Maine, and

Interstate 89 cuts across the middle part, in Vermont. The

westernmost part of the area is almost entirely in Adirondack

State Park. The middle part of the area, in Vermont and

Massachusetts, has more than 25 State forests. The Baxter,

Connecticut Lakes, and Coleman State Parks and the Allagash

Wilderness Waterway are in the eastern part of the area, in

northern Maine. The Green Mountain and White Mountain

National Forests are in the central and eastern parts of the

MLRA, respectively.

Physiography

The westernmost part of this area is primarily in the

Adirondack Province of the Appalachian Highlands. A small

area in the southern end of the western part is in the Mohawk

Section of the Appalachian Plateaus Province of the same

division. The easternmost part, primarily in northern Maine, is

in the New England Upland Section of the New England
of the United States 471

Province of the Appalachian Highlands. The southwestern half

of this part is in the White Mountain Section of the New

England Province of the Appalachian Highlands, and the

middle part of the MLRA is in the Green Mountain Section of

the same province and division. The mountains and foothills in

this MLRA are commonly rounded. They are underlain by

bedrock and are typically covered with thin deposits of glacial

till. The more rugged mountain areas are separated by highgradient streams coursing through steep areas of colluvium or

talus-laden valleys. Many glacially broadened valleys are filled

with glacial outwash and have numerous swamps and lakes.

The mountains and foothills are moderately steep to very steep,

and the valleys are nearly level to sloping. Elevation generally

ranges from 1,000 to 4,000 feet (305 to 1,220 meters), but it is

more than 5,000 feet (1,525 meters) on a few isolated peaks

and is less than 1,000 feet (305 meters) in some of the valleys,

especially in northeastern Maine. Local relief ranges from

moderate in some areas to high in ruggedly mountainous areas.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Penobscot (0102), 18 percent; St. John (0101), 16 percent;

Northeastern Lake Ontario-Lake Ontario-St. Lawrence (0415),

11 percent; Upper Hudson (0202), 11 percent; Connecticut

(0108), 10 percent; Richelieu (0201), 9 percent; Kennebec

(0103), 9 percent; Androscoggin (0104), 6 percent; Maine

Coastal (0105), 6 percent; Merrimack (0107), 1 percent; Saco

(0106), 1 percent; Connecticut Coastal (0110), 1 percent; and

St. Francois (0111), 1 percent. Almost all of the rivers draining

the Adirondack Mountains have been designated as National

Wild and Scenic Rivers. These include the Moose, Black,

Canada Creek, Independence, Beaver, Oswegatchie, Grass,

Raquette, St. Regis, Saranac, Ausable, Bouquet, Salmon,

Hudson, and Sacandaga Rivers. In the central part of the

MLRA, the Green Mountains are drained by numerous rivers

that empty into the Hudson River or Lake Champlain to the

west or the Connecticut River to the east. These include the

Missisquoi, Lamoille, Winooski, and White Rivers, Otter Creek,

and the Batten Kill and West Rivers. The major rivers in the

part of this area in Maine include the Allagash and Aroostook

Rivers, the East and West Branches of the Penobscot River, and

the Androscoggin River.

Geology

The entire area was glaciated by the last continental ice

sheet. In addition, evidence on the more rugged mountain

peaks indicates that alpine glaciation may have lingered after

the retreat of Wisconsin ice. A thin mantle of till covers most of

the bedrock. Sandy glacial outwash has been deposited in

many stream valleys, and ice-contact, stratified drift (on kames

and eskers) has been deposited on the walls of the valleys.

When the European and African Continents were squeezed up

against the North American Continent by plate tectonic activity,

the mountains in this MLRA must have appeared to be similar

to the present Himalaya Mountains. For the past 500 million

years, as the Atlantic Ocean opened up and the European and

African continental plates were pushed east, erosion has been

the dominant process. Only the roots of those ancient

mountains remain in the area today. The bedrock consists

primarily of igneous and metamorphic rocks. The metamorphic

rocks (gneiss, schist, slate, metanorthosite, marble, and

quartzite) are the oldest rocks. The igneous rocks, primarily

granite and granodiorite, were intruded into the metamorphic

rocks during the Triassic and Cretaceous periods. The

deformation history and the weathering of these rocks have left

numerous fractures, joints, bedding plane partings, and cleavage

partings that now contain freshwater.

Climate

The average annual precipitation in most of this area is 32 to

45 inches (815 to 1,145 millimeters). It is typically 45 to 60

inches (1,145 to 1,525 millimeters) at the higher elevations in

the mountains and is 60 to 105 inches (1,525 to 2,665

millimeters) on the highest peaks in the Green and White

Mountains. More precipitation generally falls in summer than

in winter. Most of the rainfall occurs as high-intensity,

convective thunderstorms during the summer. Heavy snowfalls

are common in winter. The average annual temperature is 35 to

46 degrees F (1 to 8 degrees C). The freeze-free period averages

145 days and ranges from 110 to 185 days, decreasing in length

with elevation.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 9.8%; ground water, 5.1%

Livestock—surface water, 0.2%; ground water, 0.4%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 80.1%; ground water, 4.5%

The total withdrawals average 410 million gallons per day

(1,550 million liters per day). About 10 percent is from ground

water sources, and 90 percent is from surface water sources.

Precipitation, perennial streams, and lakes provide an

abundance of water. In the parts of the MLRA in New York and

Vermont, the surface water is used primarily for recreation and

the steep terrain provides numerous opportunities for

hydropower facilities. The surface water in the part of the
472 Major Land Resource Areas

MLRA in New Hampshire, Maine, and Massachusetts is used

for light industry (textile and paper mills) and public supply.

The surface water throughout the MLRA generally is of

excellent quality. Acid rain is a problem. The acidity removes

metals, such as aluminum, iron, and mercury, from soils, and

these contaminants enter the streams, lakes, and reservoirs and

eventually enter the food chain.

Ground water is abundant in deep glacial outwash in valleys

but is scarce in the till and bedrock on uplands. Wells in the

glacial till yield moderate quantities of water for domestic use.

The water from the glacial aquifers can be soft to very hard, but

it typically has less than 150 parts per million (milligrams per

liter) total dissolved solids. The crystalline bedrock throughout

this area yields moderately hard ground water of generally

excellent quality. The level of total dissolved solids is very

low; the median value is less than 150 parts per million

(milligrams per liter). In the water from some wells, high,

naturally occurring levels of iron and manganese can exceed

the secondary standards for drinking water of 300 and 50 parts

per billion (micrograms per liter), respectively. In Maine and

New Hampshire, high, naturally occurring levels of radon cause

problems in about 5 percent of the wells tested in this aquifer.

Wells in granite with high amounts of muscovite and biotite

appear to be the source of the radon-222.

Soils

The dominant soil orders in this MLRA are Inceptisols and

Spodosols. The soils in the area dominantly have a frigid soil

temperature regime, an aquic or udic soil moisture regime, and

isotic or mixed mineralogy. At high elevations (above 3,000

feet, or 915 meters, in the Adirondack Mountains), the soil

temperature regime is cryic. The soils are shallow to very deep,

generally somewhat excessively drained to poorly drained, and

loamy. Humaquepts (Burnham series) and Epiaquepts (Monarda

series) formed in dense till in depressions on till plains.

Haplorthods formed in loamy till on hills, mountains, and

plateaus (Berkshire, Lyman, Thorndike, and Tunbridge series)

and in dense till on drumlins, hills, and ridges (Becket,

Colonel, Dixfield, Howland, Marlow, Peru, and Plaisted series).

Biological Resources

This area supports northern hardwoods, spruce, and fir. The

most common trees are sugar maple, American beech, yellow

birch, black cherry, white pine, balsam fir, red spruce, eastern

hemlock, black spruce, and trembling aspen. Sugar maple,

yellow birch, American beech, red spruce, and eastern hemlock

are dominant on the better drained soils on hills and ridges.

Red spruce and balsam fir are dominant on the wetter soils on

long, gentle slopes and in depressions. Stunted balsam fir and

red spruce are common on many of the high mountaintops.

Some of the major wildlife species in this area are whitetailed deer, snowshoe hare, and ruffed grouse.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 1%

Grassland—private, 1%

Forest—private, 85%; Federal, 5%

Urban development—private, 2%

Water—private, 5%

Other—private, 1%

The forested areas support northern hardwoods, spruce, and

fir. Wood for lumber and pulp for the paper industry are the

principal forest products. Maple sugar is an important product

in many areas. Most farming is a part-time enterprise occurring

on isolated farms. Much of the area in the Adirondacks in New

York is in a State park. Although most of the area in New

England is privately owned, a large part is in national forests,

State forests, or State parks. This MLRA is widely used for yearround recreation. A small acreage is used for residential

development.

The major soil resource concerns in this area are related to

forestry and recreational development. They include sheet, rill,

and gully erosion. Forest management concerns include erosion

in scarified areas used as log decks and in areas along logging

roads and skidder ruts that focus runoff up and down the slope.

Construction sites for cottage and housing developments

expose soil to the elements. The hazard of erosion becomes

severe as the extent of disturbed areas and the slope increase.

Erosion also is a severe hazard on ski slopes and in

snowboarding areas because of the steepness and length of

slopes and the difficulty in establishing stabilizing vegetation.

Erosion on logging roads and skid trails is a potentially serious

land use problem. Rill and gully erosion can occur in crop

fields.

Conservation practices on forestland generally include forest

stand improvement and proper construction, use, and

maintenance of skid trails, water bars, access roads, and log

landings. Critical area planting and sediment-control measures

are needed on construction sites, ski slopes, and recreation

trails. Conservation practices on cropland generally include

conservation tillage, contour stripcropping, crop rotations, crop

residue management (primarily mulch-till), cover crops,

diversions, and grassed waterways. 
of the United States 473

Figure 144A-1: Location of MLRA 144A in Land Resource Region R.

144A—New England and Eastern New

York Upland, Southern Part

This area (shown in fig. 144A-1) is in New York (29 percent),

Massachusetts (26 percent), Connecticut (20 percent), New

Hampshire (10 percent), New Jersey (8 percent), Rhode Island

(6 percent), and Vermont (1 percent). Also, Pennsylvania and

Maine have a few square miles of this area. The MLRA makes

up about 18,590 square miles (48,180 square kilometers). It

consists of two separate parts, one east of MLRA 145 and one

west of MLRA 145. The eastern part of MLRA 144A is

primarily in Connecticut, Rhode Island, and Massachusetts,

and the western part is primarily in southeastern New York. The

western part includes the cities of Troy, Albany, and

Poughkeepsie, New York, and the northern boroughs of New

York City, in the Hudson River Valley. It also includes

numerous cities on the New Jersey side of the Hudson River,

across from New York City. The eastern part of the MLRA

includes Storrs, Norwich, and New London, Connecticut;

Providence, Rhode Island; Worcester, Boston, and New

Bedford, Massachusetts; and Portsmouth, Concord, and

Manchester, New Hampshire. The highways in the MLRA

include Interstates 80, 84, 87, 89, 90, 93, and 95 and numerous

extensions of Interstate 95.

This MLRA includes the West Point Military Academy in

New York, the New London Naval Submarine Base and the

United States Coast Guard Academy in Connecticut, and the

South Weymouth Naval Air Station and Fort Devens Military

Reservation in Massachusetts. It also includes the Saratoga

National Historic Park in New York; the Cape Cod National

Seashore, Minuteman National Historic Park, Wood’s Hole

Oceanographic Institution, and Martha’s Vineyard State Forest

in Massachusetts; and the first State forest in New England, the

Meshomasic State Forest in Connecticut. A large number of

State forests and State parks are throughout this MLRA.

Physiography

The eastern half of the eastern part of this MLRA is in the

Seaboard Lowland Section of the New England Province of the

Appalachian Highlands. The western half of the eastern part

and the southeastern half of the western part are in the New

England Upland Section of the same province and division.

The northwestern half of the western part is in the Hudson

Valley Section of the Valley and Ridge Province of the

Appalachian Highlands. This MLRA is a very scenic area of

rolling to hilly uplands that are broken by many gently sloping

to level valleys that terminate in coastal lowlands. Elevation

ranges from sea level to 1,000 feet (0 to 305 meters) in much of

the area, but it is 2,000 feet (610 meters) on some hills. Relief is

mostly about 6 to 65 feet (2 to 20 meters) in the valleys and

about 80 to 330 feet (25 to 100 meters) in the uplands.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Upper Hudson (0202), 22 percent; Connecticut Coastal (0110),

20 percent; Massachusetts-Rhode Island Coastal (0109), 19

percent; Merrimack (0107), 12 percent; Lower Hudson-Long

Island (0203), 11 percent; Connecticut (0108), 9 percent; Saco

(0106), 3 percent; Delaware (0204), 2 percent; and Richelieu

(0201), 2 percent. The Hudson River flows south down the

center of the long, narrow western part of this MLRA. The

Housatonic and Connecticut Rivers are in the part of the

MLRA in Connecticut. The Pawtuxet, Pawcatuck, Blackstone,

and Wood Rivers are in the part in Rhode Island, and the

Blackstone, Merrimack, Nashua, Mystic, and Charles Rivers are

in the part in Massachusetts.

Geology

This area has been glaciated and consists almost entirely of

till plains and drumlins dissected by narrow valleys with a thin

mantle of till. The southernmost boundary of the area marks the

farthest southward extent of glaciation on the eastern seaboard.

The river valleys and coastal plains are filled with glacial lake

sediments, marine sediments, and glacial outwash. The bedrock

in the eastern half of the area consists primarily of igneous and

metamorphic rocks of early Paleozoic age. Granite is the most

common igneous rock, and gneiss, schist, and slate are the most

common metamorphic rocks. In the parts of the MLRA in

northeastern Pennsylvania and in eastern and southeastern New

York, Devonian- to Pennsylvanian-age sandstone, shale, and

limestone bedrock is dominant. Carbonate rocks, primarily

dolomite and limestone, are the dominant kinds of bedrock in

the part of this MLRA in northwestern Connecticut.
474 Major Land Resource Areas

Climate

The average annual precipitation is 35 to 45 inches (890 to

1,145 millimeters) in the Hudson Valley, which is in the

northern half of the western part of this area. It is 45 to 54

inches (1,145 to 1,370 millimeters) in the south end of the

western part of the area and in most of the eastern part of the

area. The precipitation generally is evenly distributed

throughout the year. Near the coast, however, it is slightly

lower in summer. It is slightly higher in spring and fall in inland

areas. Rainfall occurs as high-intensity, convective

thunderstorms during the summer. During the winter, most of

the precipitation occurs as moderate-intensity storms

(northeasters) that produce large amounts of rain or snow. The

average annual temperature is 44 to 54 degrees F (6 to 12

degrees C), increasing from north to south. The freeze-free

period averages 190 days and ranges from 145 to 240 days,

increasing in length to the south.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 33.3%; ground water, 3.9%

Livestock—surface water, 0.0%; ground water, 0.1%

Irrigation—surface water, 1.4%; ground water, 0.1%

Other—surface water, 56.5%; ground water, 4.7%

The total withdrawals average 6,950 million gallons per day

(26,305 million liters per day). This MLRA ranks eighth among

all of the MLRAs in total amount of water used. About 9

percent is from ground water sources, and 91 percent is from

surface water sources. Abundant precipitation, many perennial

streams, and many natural lakes and ponds are important

sources of surface water in this area. Many large and small

reservoirs provide municipal and industrial water to urban areas

that may lack sufficient water. For example, aqueducts that

divert water from reservoirs in the basin of the Merrimack River

provide half of the public water for Boston and many of its

suburbs in eastern Massachusetts. The surface water in the area

is suitable for almost all uses.

Some ground water is pumped for domestic use from the

glacial till that covers most of this area. The quality of the

ground water in the till is the same as that of the water in the

stratified drift and valley fill aquifer. The stratified drift and

glacial outwash deposits that fill the river valleys throughout

this MLRA are the primary sources of most of the public water

supply. Water from these units is very fresh. The water has not

remained in this shallow aquifer for a very long period, and

almost all of the unconsolidated sediments consist of quartz and

feldspars, which offer few minerals for dissolution in water. The

level of total dissolved solids typically ranges from 50 to 150

parts per million (milligrams per liter). The water is typically

soft, but it can be hard in local areas where the more soluble

minerals occur in the drift, for example in western Connecticut,

where glaciers eroded the carbonate bedrock. High, naturally

occurring levels of iron and manganese can occur, but the

median levels of these metals generally are below the national

and State primary standards for drinking water. Ground water in

the valley fill generally is acidic. Corrosion of iron, lead, and

concrete water lines is common in this area.

Many wells provide good-quality ground water from

fractures, bedding planes, and joints in the crystalline igneous

and metamorphic bedrock underlying almost all of this area.

This aquifer provides water mainly for domestic use but also for

public supply and industrial uses. This ground water is slightly

alkaline. It has a low level of total dissolved solids, about 120

parts per million (milligrams per liter). In some areas the water

has high levels of naturally occurring iron and manganese that

exceed the national and State secondary standards for drinking

water of 300 and 50 parts per billion (micrograms per liter),

respectively. Water from wells that penetrate granite with high

amounts of muscovite and biotite can contain high levels of a

naturally occurring radionuclide, radon-222. This radionuclide

can produce an odorless and inert gas that can cause health

problems for humans when it collects in showers, bathrooms,

and basements of residences.

Some younger carbonate and sandstone bedrock units are

aquifers in the parts of this area in eastern New York,

northwestern Connecticut, and northwestern Pennsylvania.

Water from the sandstone units typically has 200 or less parts

per million (milligrams per liter) total dissolved solids and

commonly is soft. Water from the carbonate units typically has

250 or more parts per million (milligrams per liter) total

dissolved solids and typically is very hard. Water from

carbonate units in eastern New York is the only water from

aquifers in the area that exceeds the national secondary drinking

water standard for total dissolved solids of 500 parts per million

(milligrams per liter). The water from both types of bedrock is

slightly alkaline.

Because of a shallow depth to water and the openings in the

rocks, all of the aquifers in this MLRA are susceptible to

contamination from surface activities.

Soils

The dominant soil orders in this MLRA are Entisols,

Histosols, and Inceptisols. The soils in the area dominantly

have a mesic soil temperature regime, an aquic or udic soil

moisture regime, and mixed mineralogy. They generally are

very deep, somewhat excessively drained to poorly drained,

and loamy or sandy. Udorthents (Hinckley series) and

Udipsamments (Windsor series) formed in outwash deposits on

outwash plains, terraces, kames, and eskers. Haplosaprists

(Freetown series) formed in organic material in depressions on

uplands and outwash plains. Dystrudepts formed in till, loamy

sediments over till, and dense till on till plains, hills, and ridges

(Canton, Charlton, Chatfield, Gloucester, Hollis, Montauk,
of the United States 475

Paxton, Scituate, Sutton, and Woodbridge series) and in

outwash deposits on outwash plains and terraces (Merrimac

series). Endoaquepts (Leicester and Ridgebury series) and

Epiaquepts (Ridgebury series) formed in till in depressions on

hills and in drainageways. Fragiudults (Rockaway series)

formed in till on hills.

Biological Resources

This area was cleared for agriculture in colonial times. The

agricultural land was abandoned at the turn of the last century

and then was reforested. The area is currently undergoing

suburban and rural development. Historic and modern types of

vegetation are similar. The area supports a mixture of northern

and central hardwoods. Sugar maple, birch, and beech, as well

as oaks and hickories, are the major species. White pine and

hemlock are the dominant conifers. Pitch pine and red pine

grow on sandy soils that formed in outwash. Red maple grows

on the wetter sites. Northern white-cedar reaches its northern

limit in bogs in this area. The nonnative, invasive plants

include Japanese barberry, Asiatic bittersweet, and Norway

maple. The most common understory plants are moosewood

and hobblebush in the northern part of the MLRA and

dogwood in the southern part. Abandoned agricultural land is

dominated by white pine and paper birch in the northern part of

the area and red cedar and gray birch in the southern part.

Numerous unique habitats are in scattered areas throughout

this MLRA. Some of the maritime habitats include coastal

grasslands, heaths, and dunes; tidal wetlands of estuaries; and

freshwater tidal reaches of the major rivers. Away from the coast,

freshwater marshes, swamps, flood plains, lowlands, areas of

peat, sand barrens, rocky summits, limestone fens, and glades

occur.

Black bear, beaver, fisher, wild turkey, vultures, and forest

songbirds are woodland species that are increasing in

population in this area. Animals that are tolerant of human

settlement also are increasing in population. Examples are

white-tailed deer, opossum, skunk, raccoon, and coyote. The

species that are decreasing in population are animals that

inhabit more open areas, such as woodchuck, vole, and red fox,

and such birds as bobolinks, meadowlarks, whippoorwills, and

nighthawks. The species of fish in the area include brook trout,

brown trout, rainbow trout, largemouth bass, chain pickerel,

flounder, bluefish, and striped bass.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 7%

Grassland—private, 4%

Forest—private, 50%; Federal, 1%

Urban development—private, 28%

Water—private, 6%

Other—private, 4%

About one-half of this area is in hardwood and pine forests.

Most of the forests are in small holdings. Some are State forests

or other large holdings. The forests in the MLRA are used for

wood products and for hunting and other kinds of recreation.

The acreage used for urban development is increasing rapidly

in this area. Agriculture in the area is dominated by dairy,

nursery, and greenhouse stock, much of which is driven by the

increase in residential development and the demand for

landscaping materials. Some forage crops for dairy cattle are

still grown, and truck crops, small fruits, and apples are grown

on some farms, mainly near the larger towns and cities. Many

farmsteads are used as rural residences, and the residents earn

their living from nonfarm occupations.

The major soil resource concerns on cropland and forestland

are sheet and rill erosion, maintenance of the content of organic

matter and productivity of the soils, and management of soil

moisture. Storm-water runoff and subsequent erosion and

sedimentation are the primary concerns in managing areas of

urban expansion.

Conservation practices on cropland generally include

systems of crop residue management, especially conservation

tillage; winter cover crops; rotations of annual crops and grasses

and legumes; contour farming; irrigation water management;

compost facilities; and nutrient, manure, and pesticide

management. Excluding dairy cattle from wetlands and

watercourses and developing rotational grazing systems help to

control erosion and protect water quality. Storm-water

management and erosion- and sediment-control practices are

needed in the rapidly expanding urban areas. 

144B—New England and Eastern New

York Upland, Northern Part

This area (shown in fig. 144B-1) is in Maine (56 percent),

New Hampshire (22 percent), Vermont (14 percent),

Massachusetts (5 percent), New York (2 percent), and

Connecticut (1 percent). It makes up about 20,500 square miles

(53,125 square kilometers). Most of this area is in Maine and

New Hampshire, but a small, separate part is on the VermontMassachusetts border with New York. The majority of Maine’s

population is in this MLRA. This is the easternmost MLRA in

the country. It includes the cities of Bangor, Augusta, and

Portland, Maine; the towns of Littleton, Plymouth, and Laconia,

New Hampshire; and the towns of Montpelier, Barre, and St.

Johnsbury, Vermont. The separate part of the MLRA on the

eastern border of New York has no cities. Interstates 89, 90, 91,

93, and 95 cross different parts of this MLRA. Some of the

White Mountain National Forest is in the part of the MLRA in

New Hampshire, and the Acadia National Park is in the part in

Maine. The Rachel Carson National Wildlife Refuge is in the

part in southeast Maine. A large number of State forests and

State parks are throughout this MLRA.
476 Major Land Resource Areas

Figure 144B-1: Location of MLRA 144B in Land Resource Region R.

Physiography

This area is the New England Province of the Appalachian

Highlands. The separate western part of the area is in the

Taconic Section of the province. The rest of the area is mostly

in the New England Upland Section. The part in southeastern

Maine is in the Seaboard Lowland Section. This MLRA

includes the entire coastal zone of Maine and extends inland

along the major river valleys. Most of the area is characterized

by rolling to hilly uplands. The area has some isolated

mountain peaks. In the part of the area in southeastern Maine,

gently sloping to level valleys terminate in coastal lowlands.

Elevation ranges from sea level to 1,000 feet (0 to 305 meters)

in much of the area. It is 2,000 feet (610 meters) on some hills

and 2,950 feet (900 meters) on a few isolated peaks. Local relief

is mostly low or moderate. It generally is highest in the

northern part of the area and decreases as sea level is

approached. An exception is the Taconic Mountains along the

New York-Massachusetts border, where relief is substantial.

Relief is mostly about 5 to 65 feet (2 to 20 meters) in the valleys

and about 80 to 330 feet (25 to 100 meters) in the uplands.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Connecticut (0108), 20 percent; Maine Coastal (0105), 15

percent; Saco (0106), 15 percent; Kennebec (0103), 13 percent;

Merrimack (0107), 11 percent; Penobscot (0102), 9 percent;

Androscoggin (0104), 6 percent; Richelieu (0201), 4 percent;

Upper Hudson (0202), 3 percent; St. Francois (0111), 2 percent;

and Connecticut Coastal (0110), 2 percent. In this area, the

Piscataqua and Saco Rivers begin in New Hampshire and flow

into Maine. The Penobscot and Saco Rivers are in the part of

this area in Maine. Another major river in the area is the

Merrimack River in New Hampshire. The part of the area in

Vermont encompasses the upper end of the Connecticut River

drainage and the headwaters of the Lamoille and Winooski

Rivers. The small, separate part of the MLRA on the eastern

border of New York has short reaches of the Batten Kill River in

Vermont, the Kinderhook River in New York, and the

headwaters of the Housatonic River in Massachusetts.

Geology

Most of this MLRA is characterized by till-mantled, rolling

to hilly uplands. The northern and eastern parts of the area are

underlain mostly by granite, gneiss, and schist bedrock.

Limestone, dolomite, and marble beds interspersed with basalt

flows occur in the southern and western parts. Stratified drift

deposits of unconsolidated sand and gravel, primarily glacial

outwash, fill most of the narrow river valleys. Some marine

sediments occur at the lower end of the valleys that terminate in

the coastal lowlands in southeastern Maine. Some glacial lake

sediments occur on valley floors behind glacial moraines. The

areas of marine and glacial lake sediments are not extensive but

are important agricultural areas.

Climate

The average annual precipitation in most of this area is 33 to

45 inches (840 to 1,145 millimeters). It is 45 to 69 inches

(1,145 to 1,755 millimeters) in a few scattered, higher elevation

areas and along the coast. The precipitation generally is evenly

distributed throughout the year. Near the coast, however, it is

slightly lower in summer. In inland areas, it is slightly higher in

spring and fall. Rainfall occurs as high-intensity, convective

thunderstorms during the summer. During the winter, most of

the precipitation occurs as moderate-intensity storms

(northeasters) that produce large amounts of rain or snow.

Heavy snowfalls commonly occur late in winter. The average

annual temperature is 39 to 48 degrees F (4 to 9 degrees C). The

freeze-free period averages 160 days and ranges from 120 to

195 days. Temperatures and the length of the freeze-free period

increase from north to south and closer to the coast.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 13.4%; ground water, 4.5%

Livestock—surface water, 0.2%; ground water, 0.3%

Irrigation—surface water, 0.2%; ground water, 0.0%

Other—surface water, 73.2%; ground water, 8.3%

The total withdrawals average 885 million gallons per day

(3,350 million liters per day). About 13 percent is from ground

water sources, and 87 percent is from surface water sources.

Abundant precipitation, many perennial streams, and many
of the United States 477

natural lakes and ponds are important sources of surface water.

Many large and small reservoirs provide municipal and

industrial water. The surface water in the area is of good quality

and is suitable for almost all uses with no or minimal treatment.

Acid rain and municipal and industrial waste discharges are the

primary sources of contamination of the surface water.

Ground water is scarce on the till-mantled uplands but is

abundant in the deep outwash deposits in the valleys. Most

public supplies and industries that use ground water obtain the

water from the stratified drift aquifer in the river valleys. The

water from this aquifer is soft to very hard, is acidic, and has

very low levels of total dissolved solids, 75 to 125 parts per

million (milligrams per liter). The aquifer is only about 100 feet

(30 meters) thick, and the water table is typically at a depth of

30 feet (10 meters). As a result, water in the aquifer is very

susceptible to contamination from surface activities.

Domestic and some public supply and light industry water is

obtained from wells drilled in the granite, gneiss, and schist

bedrock under the uplands in Vermont, New Hampshire, and

Maine. This water has slightly more total dissolved solids and

generally is harder than the water in the valley fill aquifers.

Also, there are more instances of iron concentrations exceeding

300 parts per billion (micrograms per liter) in water from the

crystalline bedrock aquifer. This is the national and State

secondary standard for iron in drinking water. High levels of

radon-222 occur in wells drilled into granite that has high

amounts of muscovite and biotite.

Industrial and domestic wells pump water from a carbonate

aquifer on the western edge of Massachusetts, in the northeast

corner of Connecticut, and along the eastern border of New

York. This aquifer consists of beds of limestone, dolomite, and

marble interspersed with beds of schist and quartzite. The water

from this aquifer is very hard and has more than 500 parts per

million (milligrams per liter) total dissolved solids. This level

exceeds the national secondary drinking water standard.

Soils

The dominant soil orders in this MLRA are Inceptisols and

Spodosols. The soils in the area dominantly have a frigid soil

temperature regime, an aquic or udic soil moisture regime, and

isotic, illitic, or mixed mineralogy. They are shallow to very

deep, generally excessively drained to poorly drained, and

loamy or sandy. Eutrudepts (Buxton series) and Epiaquepts

(Scantic series) formed in glaciomarine or glaciolacustrine

deposits on coastal lowlands and in valleys. Dystrudepts

formed in till on till plains and moraines (Lanesboro, Shelburne,

and Colrain series) and on hills and ridges (Taconic series).

Haplorthods formed in glaciofluvial deposits on outwash plains

and eskers (Adams and Colton series); in till on till plains,

ridges, and moraines (Bangor, Berkshire, Dixmont, Hermon,

Lyman, Monadnock, and Tunbridge series); and in dense till on

drumlins and uplands (Marlow and Peru series).

Biological Resources

This area supports northern hardwoods. Beech, white birch,

yellow birch, sugar maple, and hemlock are dominant on the

better drained soils. Spruce and balsam fir are dominant on the

wetter soils and on mountaintops. The northern aspects of

mountain slopes favor spruce and fir, and the southern aspects

support northern hardwoods. White pine is common on

abandoned farmland, in river valleys, and on outwash plains.

Spruce fir, mountain cranberry, and similar acid-tolerant plants

grow on alpine or subalpine mountaintops.

Some of the major wildlife species in this area are whitetailed deer, beaver, snowshoe hare, muskrat, mink, and ruffed

grouse. The species of fish in the area include trout, salmon,

alewife, striped bass, smelt, and eel.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 4%

Grassland—private, 2%

Forest—private, 76%; Federal, 1%

Urban development—private, 7%

Water—private, 6%

Other—private, 4%

Almost four-fifths of this area is in hardwood and conifer

forests, most of which are in small holdings. Some areas are in

State forests or in other large holdings. Sawlogs and pulp for

paper mills are the principal products, but maple syrup and

Christmas trees are produced on some sites. The forests are

widely used for hunting and other kinds of recreation. A

significant acreage of the forestland is used for residential and

leisure home developments. Forage crops for dairy cattle are

grown on most of the cropland in the area. Truck crops, small

fruits, and apples are grown on some farms, mainly near the

larger towns and cities. Native lowbush blueberries are

produced in an area in the extreme eastern part of this MLRA.

This is the largest blueberry production area in the world. Many

farmsteads are used as rural residences, and the residents earn

their living from nonfarm occupations. Urban development is

increasing in this populous MLRA.

The major soil resource concerns are sheet, rill, and gully

erosion on cropland and on logging roads and forest landings

and sedimentation in urban areas during periods of

construction. Other resource concerns on cropland include

nutrient management, maintenance of the content of organic

matter in the soils, maintenance of soil quality, and the loss of

important farmland to development.

Conservation practices on cropland generally include crop

residue management (no-till), diversions, grassed waterways,

cover crops, and filter strips. They also include management of

the storage and utilization of all sources of nutrients on farms.
478 Major Land Resource Areas

Figure 145-1: Location of MLRA 145 in Land Resource Region R.

Conservation practices on forestland generally include riparian

buffer zones, sediment control on roads and in ditches, and

proper stream crossings, which prevent sedimentation and help

to maintain water quality. 

145—Connecticut Valley

This area (shown in fig. 145-1) is in Connecticut (45

percent), Massachusetts (30 percent), New Hampshire (15

percent), and Vermont (10 percent). It makes up about 2,130

square miles (5,520 square kilometers). It includes the cities of

Springfield, Massachusetts, and Hartford, Connecticut, and the

towns of Lebanon and Claremont, New Hampshire; White River

Junction and Brattleboro, Vermont; Amherst and Northampton,

Massachusetts; and Middletown, Meriden, and New Haven,

Connecticut. Interstate 91 follows the floor of the Connecticut

River Valley for almost the entire length of this MLRA.

Interstate 95 crosses the southern tip of the area, in New Haven,

and Interstates 84, 90, and 89 cross the area. Dinosaur State

Park in Connecticut and the Holyoke Dam in Massachusetts

provide excellent sites for observing fossil dinosaur tracks. A

large number of State forests and State parks are throughout this

area.

Physiography

This area is in the New England Upland Section of the New

England Province of the Appalachian Highlands. The nearly

level floor of the Connecticut River Valley makes up most of

the area. Nearly level to sloping lowlands are at the outer edges

of the river valley. These lowlands are broken by isolated,

north- to south-trending trap-rock ridges that are hilly and

steep. Elevation ranges from sea level to 330 feet (100 meters)

in the lowlands and from 650 to 1,000 feet (200 to 305 meters)

on ridges. Local relief is typically 0 to 65 feet (0 to 20 meters)

in the lowlands and about 160 to 330 feet (50 to 100 meters) on

ridges.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Connecticut (0108), 85 percent, and Connecticut Coastal

(0110), 15 percent. This area is on the floor of the Connecticut

River Valley for nearly the entire length of the valley within the

United States. The Connecticut River empties into Long Island

Sound in the southeast corner of the area.

Geology

Recent alluvium has been deposited on the nearly level

flood plain along the Connecticut River since the glacial

retreat about 10,000 to 12,000 years ago. These deposits

created some of the most productive agricultural soils in New

England. Glacial lake deposits, outwash, and recent alluvial

deposits dominate the part of the valley north of Rocky Hill,

Connecticut. A great freshwater glacial lake, Lake Hitchcock,

extended from Rocky Hill northward to Lyme, New Hampshire.

For many thousands of years, this lake received sediments from

the contributing uplands. Very thick deposits of varved clay,

silt, and very fine sand were in the lake. Today, these deposits

are as much as 200 feet thick. Water flowing off the higher hills

along the valley created great delta deposits of sand and gravel.

Outwash deposits along the valley walls were created whenever

the sand and gravel were unable to reach the lake because of ice

blockage. These kame terraces appear as linear deposits along

the valley. After the glacial retreat, winds deposited fine sand

on the lake deposits and over much of southern New England.

This deposition resulted in dune deposits on the lake bottom

and a loess cap throughout much of southern New England.

Late Triassic and early Jurassic bedrock lies beneath the

glacial sediments. Rift valleys developed in this area during the

migration of the continents to their present locations. These

large basins were filled with a basalt-sandstone rock sequence

locally known as the Newark Supergroup. These rocks occur

from Nova Scotia to South Carolina. The bedrock in the

Connecticut Valley consists of this sandstone, shale, and

conglomerate sequence. Basalt flows along the rift zones

periodically spread across these shallow freshwater sediments.

Today, these igneous rocks form many of the landmarks

throughout the upper valley, such as Mt. Tom, Mt. Holyoke, and

Mt. Sugarloaf.

Climate

The average annual precipitation in this area is 33 to 52

inches (840 to 1,320 millimeters). The precipitation is evenly
of the United States 479

distributed throughout the year. Rainfall occurs as highintensity, convective thunderstorms during the summer. During

the winter, most of the precipitation occurs as moderateintensity storms (northeasters) that produce large amounts of

rain or snow. The seasonal snowfall averages 40 inches (100

centimeters). The average annual temperature is 42 to 52

degrees F (6 to 11 degrees C). The freeze-free period averages

180 days and ranges from 140 to 220 days. Temperatures and

the length of the freeze-free period increase from north to south.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 34.9%; ground water, 16.0%

Livestock—surface water, 0.0%; ground water, 0.1%

Irrigation—surface water, 3.9%; ground water, 1.2%

Other—surface water, 38.0%; ground water, 5.9%

The total withdrawals average 515 million gallons per day

(1,950 million liters per day). About 23 percent is from ground

water sources, and 77 percent is from surface water sources.

Precipitation, perennial streams, and lakes provide an

abundance of good-quality surface water in this area. Water for

municipal and industrial needs is stored in reservoirs in this area

and in adjoining areas. The surface water is of good quality, but

it commonly requires some treatment prior to use as drinking

water. Progress has been made in cleaning up municipal and

industrial waste discharges into the Connecticut River and its

tributaries.

Public supply, municipal, and industrial water is obtained

from the glacial outwash and the alluvial valley fill along the

major rivers. The ground water in this aquifer is abundant. It is

acidic, is soft to very hard, and is very low in total dissolved

solids, typically 75 to 125 parts per million (milligrams per

liter). This aquifer is typically less than 100 feet (30 meters)

thick, and the water table is often at a depth of 30 feet (10

meters). As a result, the water in the aquifer is highly

susceptible to contamination by surface activities.

Some public supply, municipal, and industrial water is

obtained from the marine sediments in the parts of this area in

Massachusetts and Connecticut. The water in this aquifer is

moderately hard and has about 250 parts per million

(milligrams per liter) total dissolved solids in the upper 200 feet

(60 meters) of the aquifer. In the lower part of the aquifer, the

level of total dissolved solids doubles and the water is very

hard. Some deposits of copper, lead, zinc sulfides, and uranium

minerals occur in this aquifer. Water pumped from areas with

ore deposits must be treated before it can be used for drinking

or for industrial purposes.

Many shallow domestic wells obtain ground water from the

till deposits that cover the bedrock in the lowlands on each side

of the flood plain along the Connecticut River. The water in the

till is very similar in quality to the water in the valley fill

aquifer. Some public supply and light industry water is

obtained from wells drilled in the igneous and metamorphic

rocks under the till in the lowlands. This water has slightly

more total dissolved solids and generally is harder than the

water in the valley fill and till aquifers. Also, there are more

instances of iron concentrations exceeding 300 parts per billion

(micrograms per liter) in the crystalline bedrock aquifer. This is

the national and State secondary standard for iron in drinking

water. High levels of radon-222 occur in wells drilled into

granite that has high amounts of muscovite and biotite.

Soils

The dominant soil orders in this MLRA are Entisols and

Inceptisols. Some Spodosols are in the northern part of the area.

The soil temperature regime generally is mesic but is frigid in

the northern part of the area. The soils in the area dominantly

have an aquic or udic soil moisture regime and mixed

mineralogy. They generally are very deep, excessively drained

to poorly drained, and clayey, loamy, or sandy. Dystrudepts

formed in outwash deposits on outwash plains and terraces

(Agawam and Merrimac series), in dense till on till plains and

hills (Ludlow and Wethersfield series), and in till on till plains,

hills, and mountains (Cardigan, Cheshire, Dutchess, and

Kearsarge series). Udorthents (Hinckley and Manchester series)

and Udipsamments (Deerfield and Windsor series) formed in

outwash on outwash plains, kames, terraces, and eskers.

Endoaquepts (Scitico series) formed in glaciolacustrine

material on terraces. Udifluvents (Hadley series) formed in

alluvium on flood plains.

Biological Resources

Historic and modern types of vegetation are similar in this

area. The area primarily supports central hardwoods. Some

northern hardwoods are at the northern extent of the MLRA.

Habitat loss and fragmentation are widespread throughout the

lower part of the Connecticut River Valley. Attempts to

cultivate infertile sandy areas were unsuccessful and have

contributed to the “barren” appearance of the sand plains and

the dominance of pitch pine in those areas. The major tree

species in the rest of the forested areas are sugar maple, birch,

beech, oaks, and hickory. White pine and hemlock are the

dominant conifers, but pitch pine and red pine are more

common on sandy soils. Red maple grows on the wetter sites.

Japanese knotweed is one nonnative, invasive plant that

hinders the growth and development of the more desirable

plants in the area. The most common understory plants are

moosewood and hobblebush in the northern part of the area and

dogwood in the southern part. Abandoned agricultural land is

dominated by white pine and paper birch in the northern part

and red cedar and gray birch in the southern part.

The important upland habitats include trap-rock ridges and

sand plains. Oak woodlands and cedar glades are common on
480 Major Land Resource Areas

Figure 146-1: Location of MLRA 146 in Land Resource Region R.

the ridges. Black oak savannas mixed with pitch pine and

varying amounts of little bluestem are common on the sand

plains. Other habitats of significance include wetlands

associated with the Connecticut River freshwater marshes,

swamps, flood plains, and lowlands. The dominant trees on the

flood plains are black willow, cottonwood, and sycamore.

Large mammals, such as white-tailed deer, moose, and black

bear, are in the forests in the northern part of this area. Animals

that are tolerant of human settlement are numerous throughout

the rest of the MLRA. Examples are white-tailed deer, opossum,

skunk, raccoon, and coyote. The species that are decreasing in

population are animals that inhabit more open areas, such as

woodchuck, vole, and red fox, and such birds as bobolinks,

meadowlarks, whippoorwills, and nighthawks. The Connecticut

River waterway is a significant anadromous fishery, supporting

alewife, herring, and American shad. Atlantic salmon are being

reintroduced, and shortnose sturgeon is in the lower reaches of

the river.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 13%

Grassland—private, 3%

Forest—private, 42%

Urban development—private, 34%

Water—private, 4%

Other—private, 4%

The hardwood and pine forests in this area are used for

residential development, recreation, wildlife habitat, and

esthetic purposes. The agricultural land in the area is used

mainly for nursery and greenhouse stock; truck crops, such as

fruits and vegetables; and tobacco. The extent of industrial and

residential development is increasing. The Connecticut Valley

is one of the most productive and valuable areas in the

Northeast because of the long growing season and the

proximity to cities and towns. Urban and industrial expansion,

however, is causing a rapid loss of agricultural land. Many of

the current agricultural fields predate the discovery of America.

Archaeological evidence indicates that these fields and the

associated anadromous fishery in the lower reaches of the valley

were used by American Indians during the Woodland period. As

a result, later settlement of the area by Europeans was

simplified.

The major soil resource concerns are sheet and rill erosion,

erosion and sedimentation caused by storm-water runoff,

maintenance of the content of organic matter and productivity

of the soils, and management of soil moisture. The protection of

agricultural land from encroaching development is a serious

resource concern.

Conservation practices on cropland generally include

systems of crop residue management (such as conservation

tillage), winter cover crops, rotations of annual crops and

grasses and legumes, contour farming, irrigation water

management, compost facilities, nutrient management, manure

management, and pesticide management. Excluding livestock

from wetlands and watercourses and developing rotational

grazing systems help to control erosion and preserve water

quality. Conservation practices that are important in areas of

community development include critical site planting and urban

storm-water management. 

146—Aroostook Area

This area is entirely in Maine (fig. 146-1). It makes up about

1,275 square miles (3,305 square kilometers). Presque Isle is the

largest city in the area. Interstate 95 ends in the town of

Houlton, at the border with New Brunswick, Canada. Aroostook

State Park, Fort Kent Historic Site, and Loring Commerce

Center are in this area. The Big Rock ski area is in the middle of

this MLRA and is on the highest point, which is Mars Hill

Mountain.

Physiography

This area is in the New England Upland Section of the New

England Province of the Appalachian Highlands. It is mostly a

nearly level to sloping lowland. Rolling hills are common in

the north-central part of the area. The lowland is broken by

isolated, north- to south-trending trap-rock ridges (basalt and

diabase dikes) that are hilly and steep. These ridges are more

common in the far northern parts of the area, near the Canadian

border. Elevation ranges from sea level to 330 feet (0 to 100
of the United States 481

meters) in the lowlands and from 650 to 1,000 feet (200 to 305

meters) on the ridges. Local relief is less than 5 feet to 65 feet (1

to 20 meters) on the lowlands. The ridges are about 165 to 330

feet (50 to 100 meters) above the lowlands.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows: St.

John (0101), 98 percent, and Penobscot (0102), 2 percent. The

St. John River is on the northern border of this area, and its

principal tributary, the Aroostook River, crosses the northcentral part of the area.

Geology

Almost all of this area is mantled with a mixture of glacial

till, outwash, stratified drift, and glacial lake and marine

sediments. The till is more prominent on the uplands in the

area, and the other surficial deposits are more common in the

valleys and lowlands. Numerous basalt and diabase dikes

occurring as north- to south-trending ridges cut across this area.

Most of the eastern half of the area is underlain by the Cary

Mills Formation, a bluish gray limestone with some dark gray

calcareous shale and siltstone layers. The rest of the area is

underlain by a variety of igneous and metamorphic rocks. The

most common igneous rocks are granite, gabbro, diorite,

granodiorite, and pegmatite. The metamorphic rocks include

schist, gneiss, quartzite, slate, phyllite, and argillite. Recent

deposits of river alluvium (unconsolidated sand and gravel)

cover the flood plains along the major rivers.

Climate

The average annual precipitation in this area is 35 to 42

inches (890 to 1,065 millimeters). The precipitation is evenly

distributed throughout the year. Rainfall occurs as highintensity, convective thunderstorms during the summer. The

seasonal snowfall averages 40 inches (100 centimeters). The

average annual temperature is 37 to 41 degrees F (3 to 5

degrees C). The freeze-free period averages 140 days and ranges

from 120 to 155 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 30.6%; ground water, 7.5%

Livestock—surface water, 0.2%; ground water, 0.1%

Irrigation—surface water, 2.2%; ground water, 0.0%

Other—surface water, 50.5%; ground water, 8.9%

The total withdrawals average 23 million gallons per day (87

million liters per day). About 17 percent is from ground water

sources, and 83 percent is from surface water sources.

Precipitation, perennial streams, lakes, and aquifers provide an

abundance of water. Water for municipal and industrial needs is

stored in reservoirs in this area and in adjoining areas. The

surface water in the area is suitable for most uses with little to

no treatment. In some soils that have dense till, the water table

is perched from late in fall to early in spring. Soils on wetlands

are saturated during a large part of the year.

The ground water used in this area typically comes from the

glacial outwash and stratified drift aquifers on the valley floors

along the St. John and Aroostook Rivers or from carbonate

bedrock on the east edge of the area. Water from both of these

aquifers is of very good quality. The median level of total

dissolved solids is 80 parts per million (milligrams per liter) in

water from the outwash and stratified drift aquifers and 256

parts per million (milligrams per liter) in the water from the

carbonate bedrock. The water from the carbonate rocks is very

hard and requires treatment for hardness, and the water from the

glacial aquifers is soft. Because of the shallow depth to the

water table in the glacial aquifers and the openings in the

carbonate rock connected to the surface, both of these aquifers

are susceptible to contamination from agriculture, urbanization,

and industry.

Homeowners in the western half of this area and in the

uplands above the river valleys typically use ground water from

either the glacial till or the igneous and metamorphic bedrock.

The water from these aquifers is of very good quality, but well

yields are typically much lower than yields from wells in the

more water-rich outwash, stratified drift, and carbonate

aquifers.

Soils

The dominant soil orders in this MLRA are Spodosols and

Inceptisols. The soils in the area dominantly have a frigid soil

temperature regime, a udic soil moisture regime, and mixed or

isotic mineralogy. They are moderately deep to very deep, well

drained to excessively drained, and loamy to sandy-skeletal.

Eutrudepts (Mapleton series) formed in till on till plains and

ridges. Haplorthods formed in till (Caribou and Conant series)

or dense till (Perham series) on till plains and ridges and in

outwash deposits (Colton and Stetson series) on terraces,

kames, eskers, and outwash plains.

Biological Resources

The native vegetation consists of both coniferous and

deciduous trees. Maine is known for its wide variety of trees.

The hardwoods include sugar maple, beech, quaking aspen,

white birch, and yellow birch. The softwoods include red

spruce, balsam fir, white pine, cedar, and tamarack. Tree

plantations have been established since the 1960s on many

farms. The typical species on these plantations are white spruce,

Norway spruce, and red pine.

Some of the major wildlife species in this area are black

bear, moose, white-tailed deer, red fox, eastern coyote,

snowshoe hare, and ruffed grouse.
482

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 13%

Grassland—private, 3%

Forest—private, 75%; Federal, 1%

Urban development—private, 4%

Water—private, 2%

Other—private, 2%

Most of this area is forested or is cropland reverting to forest.

The forest products in the area are used mainly in the paper

industry and for lumber. The cropland in the area is used mainly

for potatoes, but broccoli, oats, canola, and barley also are

grown.

The major soil resource concerns are sheet, rill, and gully

erosion caused by rainfall, intensive cropping, and outdated

methods of irrigation; the condition and tilth of the soils,

surface compaction, and sediment deposition in areas used as

cropland; and erosion and sedimentation along the forest roads

used by the logging industry.

Conservation practices on cropland generally include crop

rotations (especially where potatoes are grown), grassed

waterways in areas of concentrated flow, stripcropping, cover

crops, nutrient management, proper row direction, and

irrigation water management. Conservation practices on

forestland generally include forest stand improvement and

proper construction, use, and maintenance of water bars,

culverts, stream crossings, and access roads. 
483

Figure S-1: Location of Land Resource Region S.

S—Northern Atlantic Slope Diversified

Farming Region

This region (shown in fig. S-1) is in Pennsylvania (40

percent), Virginia (21 percent), Maryland (14 percent), West

Virginia (10 percent), New Jersey (9 percent), New York (3

percent), Massachusetts (2 percent), Delaware (1 percent), the

District of Columbia (less than 1 percent), and Rhode Island

(less than 1 percent). It makes up 40,865 square miles (105,905

square kilometers).

This is a region of coastal lowlands, coastal plains, the

piedmont, and ridges and valleys (fig. S-2). The climate is

temperate and humid. The average annual precipitation is 37 to

45 inches (940 to 1,145 millimeters) in most of the region, but

it is as high as 52 inches (1,320 millimeters) in the northeast

corner of the region. Precipitation is slightly higher during

spring and summer than during the rest of the year. The average

annual temperature is 48 to 56 degrees F (9 to 14 degrees C). In

most of the region, the freeze-free period ranges from 175 to

235 days. It is shortest in the mountains and longest along the

Atlantic Ocean and the Chesapeake Bay.

The total withdrawals of freshwater in this region average

about 8,220 million gallons per day (31,110 million liters per

day). About 81 percent is from surface water sources, and 19

percent is from ground water sources. Abundant precipitation,

numerous perennial streams, and good aquifers provide ample

supplies of good-quality water for all uses in the region. Onethird of the water used in this populous region is for public

supply. Most of the remaining water is used for mining,

municipal supply, and industry and for cooling thermoelectric

power plants.

The soils in this region are dominantly Alfisols, Ultisols, or

Inceptisols. The dominant suborders are Udalfs, Udults, and

Ochrepts. These soils commonly have a fragipan. Aquults and

Aquepts are on lowlands and in depressions, particularly on the

coastal plains. Soils on flood plains, mainly Ochrepts and

Fluvents, are of minor extent. Hydraquents, Sulfaquents, and

Sulfihemists are in tidal marshes along the Chesapeake Bay and

the Atlantic Ocean. Psamments are of major extent on the Long

Island-Cape Cod coastal lowland and of minor extent on the

coastal plains. The soils in the region dominantly have a mesic

soil temperature regime, a udic soil moisture regime, and mixed

mineralogy.
484 Major Land Resource Areas

Figure S-2: Parallel ridges and intervening valleys in an area of Land Resource Region S.

About 92 percent of this region is privately owned land,

mostly in farms. Farming is highly diversified. Truck crops,

fruits, and poultry are important sources of income, particularly

on the coastal plains. Forage crops, soybeans, and grain for

dairy and beef cattle also are important. Many large-scale

corporate farms on the coastal plains are associated with the

canning and frozen food industries. Many farms are operated

part-time by people who earn most of their living in the cities.

Rural residences are on many sites that are less favorable for

farming. Throughout the region, urban areas are encroaching on

farmland. Steep slopes occur largely in forests used for timber

production and for recreation. 
of the United States 485

Figure 147-1: Location of MLRA 147 in Land Resource Region S.

147—Northern Appalachian Ridges and

Valleys

This area (shown in fig. 147-1) is in Pennsylvania (54

percent), Virginia (23 percent), West Virginia (20 percent), and

Maryland (3 percent). It makes up about 20,750 square miles

(53,775 square kilometers). It includes the cities or towns of

Harrisburg, Williamsport, Carlisle, and State College,

Pennsylvania; Cumberland and Hagerstown, Maryland;

Martinsburg, Moorefield, and White Sulphur Springs, West

Virginia; and Winchester, Harrisonburg, and Staunton, Virginia.

From north to south, the highways crossing this area include

Interstates 80, 76, 81, 70, 68, 66, 64, and 77. Part of the

Delaware Gap and Seneca Rocks National Recreation Areas and

parts of the Jefferson, George Washington, and Monongahela

National Forests are in this MLRA. The Chesapeake and Ohio

National Historic Park and the Antietam National Battlefield

also are in this area.

Physiography

This area is in the Middle Section of the Valley and Ridge

Province of the Appalachian Highlands. It is a folded and

faulted area of parallel ridges and valleys that are carved out of

anticlines, synclines, and thrust blocks. Parallel sandstone and

shale ridges are separated by narrow to moderately broad

limestone and shale valleys. The ridges are strongly sloping to

extremely steep and have narrow, rolling crests, and the valleys

are mainly level to strongly sloping. The western side of the

area is dominantly hilly to very steep and is rougher and much

steeper than the eastern side, much of which is rolling and hilly.

Elevation generally ranges from 330 to 985 feet (100 to 300

meters) in the valleys and from 1,310 to 2,625 feet (400 to 800

meters) on the ridges and mountains. It is as high as 2,955 feet

(900 meters) on some mountain crests and is nearly 4,430 feet

(1,350 meters) on a few isolated, linear mountain ridges. Local

relief in the valleys is about 15 to 165 feet (5 to 50 meters). The

ridges rise about 660 feet (200 meters) above the adjoining

valleys.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Susquehanna (0205), 39 percent; Potomac (0207), 37 percent;

Lower Chesapeake (0208), 10 percent; Delaware (0204), 10

percent; and Kanawha (0505), 4 percent. The Susquehanna,

Potomac, Greenbrier, New, Clinch, and James Rivers are the

major streams that drain this MLRA. Reaches of the Schuylkill,

Lehigh, James, and Greenbrier Rivers and Anthony Creek have

been designated as National Wild and Scenic Rivers in this

area.

Geology

This area is underlain by Paleozoic sediments ranging in age

from Cambrian to Pennsylvanian. The resistance of these

sediments to erosion varies greatly and has a major effect on the

topography. The ridge crests are made up primarily of resistant

sandstones and conglomerate bedrock. The valleys are

underlain by less resistant shales and limestone. The

topographic orientation of the Valley and Ridge Province is

dominantly northeast to southwest. The streams follow the less

resistant rock types and cut through the more resistant rock

types at an angle of 90 degrees, forming water gaps, most of

which are along zones of intensive fracturing. As a result of this

process, a trellis drainage pattern characterizes this MLRA.

Climate

The average annual precipitation in most of this area is 31 to

45 inches (785 to 1,145 millimeters). It is typically 45 to 52

inches (1,145 to 1,320 millimeters) in the northern end of the

area, in Pennsylvania. The maximum precipitation occurs from

late winter through early summer, and the minimum occurs in

fall. About 21 to 26 inches (535 to 660 millimeters) falls during

the growing season. The average annual snowfall ranges from

16 to more than 51 inches (40 to 130 centimeters). The average

annual temperature is 44 to 57 degrees F (7 to 14 degrees C).

The freeze-free period averages 180 days and ranges from 140

to 220 days. The cooler temperatures and the shorter freeze-free

periods are at the higher elevations and the more northern

latitudes.
486 Major Land Resource Areas

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 10.2%; ground water, 3.0%

Livestock—surface water, 0.3%; ground water, 0.5%

Irrigation—surface water, 0.3%; ground water, 0.1%

Other—surface water, 76.3%; ground water, 9.4%

The total withdrawals average 1,950 million gallons per day

(7,380 million liters per day). About 13 percent is from ground

water sources, and 87 percent is from surface water sources. In

most years the supply of moisture is adequate for maximum

crop production and other needs. Short dry periods early in

summer occasionally reduce crop yields. Springs, farm ponds,

reservoirs, and streams are the principal sources of water in this

area. Streams, some ponds, and springs provide water for

livestock. Springs also provide some domestic drinking water.

The many rivers crossing this area are sources of public supply

and industrial water. Most of the surface water in the area is of

good quality and is suitable for most uses with minimal

treatment.

The abundance of ground water depends largely on

landscape and geology in this area. The most abundant water

sources are in coves and valleys underlain by carbonate rocks.

For example, the Valley and Ridge aquifers in Virginia consist

of limestone and dolomite. The water in these aquifers is low in

total dissolved solids, but it is very hard and may have a nitrate

level that exceeds the national drinking water standard of 10

parts per million (milligrams per liter). This aquifer is called the

Cambrian-Ordovician Carbonate aquifer in Tennessee, and it

includes layers of sandstone and shale as well as carbonates.

Similar rock types are used as aquifers in the parts of this area in

Maryland and Pennsylvania. These aquifers all have water of

similar quality, and they provide domestic water for rural

landowners, for industry, and for communities. The water is in

fractures, joints, and bedding planes in the sandstone and shale

layers as well as in solution openings in the limestone and

dolomite layers. Most wells are 300 or less feet (90 or less

meters) deep. Because of the shallow depth to water, the

concentration of agriculture, the urban areas, industrial plants

on the valley floors, and the solution openings in the carbonate

layers, the ground water in this area is susceptible to

contamination from human activities.

Soils

The dominant soil orders in this MLRA are Inceptisols,

Ultisols, and Alfisols. The soils in the area dominantly have a

mesic soil temperature regime, a udic soil moisture regime, and

mixed or siliceous mineralogy. They are shallow to very deep,

generally excessively drained to moderately well drained, and

loamy or clayey.

Steep and very steep, shallow to very deep, well drained,

medium textured Dystrudepts (Berks, Calvin, Dekalb, Hazleton,

Klinesville, Lehew, and Weikert series) are on the side slopes

and ridges of mountains. Nearly level to sloping, very deep,

well drained, medium textured to fine textured Hapludalfs

(Hagerstown, Duffield, Edom, Carbo, and Washington series)

are in limestone valleys. Gently sloping or sloping, deep and

very deep, well drained and moderately well drained, medium

textured to fine textured Hapludults (Bedington, Frankstown,

Leck Kill, Mertz, and Murrill series), Fragiudults (Buchanan

and Laidig series), and Paleudults (Frederick and Watahala

series) are on the lower footslopes of the ridges and in the

valleys. Most of these soils formed in residuum or colluvium

derived from limestone (some of which is cherty), sandstone, or

shale.

Nearly level to gently sloping, very deep, well drained to

poorly drained, medium textured to fine textured Eutrudepts

(Chagrin, Lobdell, and Tioga series) formed in alluvium on

flood plains along drainageways.

Biological Resources

This area supports hardwoods. White oak, red oak, black

oak, hickories, and associated upland hardwoods are the major

species. Scarlet oak, chestnut oak, hickories, and scattered

Virginia pine, pitch pine, shortleaf pine, and eastern white pine

are common on the more shallow soils and on the south aspects,

especially in the southern part of the area. Yellow-poplar, red

oak, red maple, and other species that require more moisture

grow in sheltered coves and on footslopes and north aspects.

Some of the major wildlife species in this area are whitetailed deer, wild turkey, gray squirrel, cottontail rabbit, raccoon,

red fox, gray fox, ruffed grouse, and woodchucks. Smallmouth

bass, rock bass, sunfish, catfish, and suckers are in the larger

warm-water streams. Suitable cold-water streams are stocked

with trout. Native brook trout inhabit many of the smaller

streams.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 16%; Federal, 3%

Grassland—private, 11%; Federal, 1%

Forest—private, 48%; Federal, 7%

Urban development—private, 9%; Federal, 1%

Water—private, 1%

Other—private, 3%

Most of this area is in farms. The cropland in the area is used

for a wide variety of crops, mainly corn, small grains, and

forage for dairy and beef cattle. Other important crops are

potatoes, soybeans, apples, peaches, and some tobacco and

vegetables. Dairy, beef, and poultry farms are major enterprises.
of the United States 487

The hardwood forests in the area are mainly small or mediumsize holdings, but some are larger tracts of national and State

forests, game lands, or parks. A significant acreage in the area is

used for urban development or consists of land altered by

urbanization. Much of the prime farmland in the valleys has

been developed for urban uses.

The major soil resource concerns are water erosion,

sedimentation, and maintenance of the content of organic

matter and productivity of the soils. Conservation practices on

cropland generally include conservation tillage (especially notill systems), cover crops, contour farming, return of crop

residue to the soil, and nutrient management. 

Figure 148-1: Location of MLRA 148 in Land Resource Region S.

148—Northern Piedmont

This area (shown in fig. 148-1) is in Pennsylvania (38

percent), Virginia (30 percent), Maryland (21 percent), New

Jersey (10 percent), and Delaware (1 percent). It makes up about

12,800 square miles (33,170 square kilometers). Philadelphia,

Pennsylvania, is on the eastern boundary of this area. The north

end of the MLRA, just southwest of the densely populated area

of northeast New Jersey, includes the cities of Morristown,

Plainfield, Somerset, and New Brunswick, New Jersey. The part

of the MLRA in the western suburbs of the District of Columbia

includes the cities of North Bethesda, Potomac, Rockville,

Gaithersburg, and Germantown, Maryland. Another heavily

populated area includes the greater part of Baltimore,

Maryland, and cities just to the west of Baltimore.

Charlottesville, Virginia, also is in this area. Interstates 80, 78,

76, 70, and 66 cross this area from east to west. Interstates 83

and 95 cross the area from north to south. The Chesapeake and

Ohio Canal National Historic Park, along the Potomac River,

and the Manassas National Battle Field, in northern Virginia,

are in this MLRA. The Gettysburg National Military Park, in

Pennsylvania, is just inside the west edge of the MLRA. The

Fort Detrick Military Reservation is in the part of the area in

Maryland. Many State parks and a few State forests are in this

MLRA.

Physiography

Most of this area is in the Piedmont Upland Section of the

Piedmont Province of the Appalachian Highlands. The

southwest end and the northwest portion of the southwest half

of this MLRA and the southeast portion of the northeast half of

the MLRA are in the Piedmont Lowlands Section of the same

province and division. The northwest portion of the northeast

half of the MLRA is in the New England Upland Section of the

New England Province of the Appalachian Highlands. Most of

this area is an eroded part of the Piedmont Plateau. This MLRA

is mostly gently sloping or sloping. Intrusive dikes and sills

form fairly sharp ridges that interrupt the less steep terrain.

Differential erosion has created low areas where rocks are soft

and high areas where rocks are resistant to erosion. The steeper

slopes generally are on ridges at the higher elevations or on

side slopes adjacent to drainages. Elevation is dominantly 330

to 985 feet (100 to 300 meters) but ranges from 80 to 985 feet

(25 to 300 meters) in most areas. It is as much as 1,650 feet (505

meters) or more on some ridges and isolated peaks.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Delaware (0204), 23 percent; Potomac (0207), 22 percent;

Susquehanna (0205), 20 percent; Lower Chesapeake (0208), 18

percent; Upper Chesapeake (0206), 10 percent; and Lower

Hudson-Long Island (0203), 7 percent. A number of National

Wild and Scenic Rivers occur in this area. From New Jersey to

Virginia, these rivers include the Schuylkill, Octoraro,

Patuxent, Monocacy, and Rappahannock Rivers and Goose

Creek and Deer Creek. The Delaware River separates

Pennsylvania and Delaware from New Jersey in this area. The

Susquehanna River crosses the northern end of the area, and the

Potomac River separates the District of Columbia and

Maryland from Virginia at the southern end of the area.

Geology

Most of this area is above the “fall line” on the east coast.

The fall line is the boundary between Coastal Plain sediments

and the crystalline bedrock of the interior uplands. The eastern

third of the area is underlain mainly by Lower Paleozoic to

Precambrian sediments and igneous rocks that have been

metamorphosed. The typical rock types in this part of the

MLRA are granite, gabbro, gneiss, serpentinite, marble, slate,

and schist. The central part of the area is a crustal trough or
488 Major Land Resource Areas

basin that formed during the Triassic period. This basin

represents the ancestral Atlantic Ocean that formed when the

European-African continental plate began its movement

westward from the North American plate. Many of the rocks in

this part of the MLRA are the same rocks as those in the western

British Isles, since they were deposited at a time when the North

American, European, and African plates were all one landmass.

The rocks deposited in the basins include Triassic sandstone,

shale, and conglomerate. These ancient basins have been

uplifted and are now in the uplands in this MLRA. Numerous

Jurassic diabase and basalt dikes and sills cut the sedimentary

rocks in the basins. The far western part of this MLRA is

underlain mostly by Cambrian to Silurian limestone. The

northern boundary of the MLRA marks the southernmost extent

of the Wisconsin glaciers. Earlier periods of glaciation extend

farther south in north-central New Jersey and in eastern

Pennsylvania. Unconsolidated stream alluvium (primarily sand

and gravel) fills the major river valleys.

Climate

The average annual precipitation in this area is 37 to 52

inches (940 to 1,320 millimeters). The maximum precipitation

occurs as high-intensity, convective thunderstorms in spring

and early in summer. Droughts of 10 to 14 days are common in

summer. Snowfall occurs in winter. The average annual

temperature ranges from 48 to 57 degrees F (9 to 14 degrees C).

The freeze-free period averages 205 days and ranges from 170

to 240 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 28.5%; ground water, 3.1%

Livestock—surface water, 0.2%; ground water, 0.3%

Irrigation—surface water, 0.2%; ground water, 0.1%

Other—surface water, 61.8%; ground water, 5.8%

The total withdrawals average 3,160 million gallons per day.

About 9 percent is from ground water sources, and 91 percent is

from surface water sources. Precipitation and perennial streams

are the important sources of water in this MLRA. The surface

water is of marginal quality. It is suitable for almost all uses if

properly treated. The lower Delaware, many New Jersey rivers,

and the Potomac River were degraded for many years by

sedimentation from agriculture and coal mining, acid mine

drainage and other contaminants from surface mining, and

waste discharges from cities and industrial sites. Many of these

sources have been treated, so the surface water is now improved

and is suitable for most uses with treatment. Water for urban

areas is supplied largely by municipal reservoirs. Most of the

water used for irrigation comes from streams and ponds.

Springs are common in rural areas. They provide water for

many farmsteads. Some water for irrigation comes from wells.

Shallow wells are important in rural areas, but most of the wells

in the crystalline bedrock supply a limited quantity of water.

The water in these igneous and metamorphic rocks is in joints,

fractures, and openings along cleavage planes. This water is of

excellent quality. It has less than 100 parts per million

(milligrams per liter) total dissolved solids. The principal ions

in the water are calcium, magnesium, and bicarbonate, and the

water is typically soft.

Two other sources of ground water in this area are the

alluvium filling the valley floors along most of the rivers and

fractured shale and sandstone (the Newark Group). The water

from both of these aquifers is very similar to that in the

crystalline bedrock aquifers. It typically has 125 to 250 parts

per million (milligrams per liter) total dissolved solids and is

hard. Both of these aquifers lie beneath the most agriculturally

productive soils in this area. Nitrate concentrations from

fertilizers are somewhat higher in the water from these aquifers

than in the water from any other aquifers in the area. The

median values of all wells tested, however, are only 1 or 2 parts

per million (milligrams per liter).

Some ground water is obtained from carbonate rocks in this

area. The water occurs in solution channels, fractures, and

partings in the rock, so wells in this aquifer typically produce

much greater volumes of water than wells in any other aquifer

in the area. The water is very hard, and its median value of total

dissolved solids is 325 parts per million (milligrams per liter).

The openings in the carbonate rocks extend to the surface, so

this aquifer is very vulnerable to pollution from surface

activities.

Soils

The dominant soil orders in this MLRA are Alfisols,

Inceptisols, and Ultisols. The soils in the area dominantly have

a mesic soil temperature regime, a udic soil moisture regime,

and mixed, micaceous, or kaolinitic mineralogy. They are

moderately deep to very deep, moderately well drained to

somewhat excessively drained, and loamy or loamy-skeletal.

Hapludalfs (Duffield, Neshaminy, and Penn series) and

Dystrudepts (Manor, Parker, and Mt. Airy series) formed in

residuum on hills. Fragiudalfs (Reedington series) formed in

residuum on footslopes and in drainageways. Hapludults

(Chester, Elioak, Gladstone, and Glenelg series) and

Kanhapludults (Hayesville series) formed in residuum on hills,

upland divides, and ridges. Fragiudults (Glenville series)

formed in colluvium or residuum on hills. The far northeastern

extent of the MLRA was affected by early periods of glaciation,

and many soils formed in very deep, highly weathered till. The

dominant soils in this part of the MLRA are Hapludalfs

(Washington and Bartley series) and Fragiudults (Annandale

and Califon series).
of the United States 489

Biological Resources

This area supports deciduous hardwoods. Chestnut oak,

white oak, red oak, hickories, ash, American elm, and yellowpoplar are the major species. Yellow-poplar is especially

abundant on the northeast-facing slopes. Tree growth and wood

production are considerably less extensive in the Triassic

basins than elsewhere in the area. Black walnut and black

cherry grow on the well drained soils on flood plains. Eastern

redcedar is common in many areas of abandoned cropland.

Some of the major wildlife species in this area are whitetailed deer, fox, raccoon, muskrat, opossum, gray squirrel,

cottontail, weasel, pheasant, ruffed grouse, and mourning

dove. The abundance of black bear is increasing in the less

densely populated, more mountainous northwest portion of the

northeast half of this MLRA.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 29%

Grassland—private, 10%

Forest—private, 25%

Urban development—private, 32%

Water—private, 2%

Other—private, 2%

Approximately one-third of this area is in farms, and onethird either is urban or is urbanizing rapidly. The farms are

intensively cropped in Maryland, in Pennsylvania, and in most

of New Jersey. They are mostly in pasture or woodland in the

northern parts of New Jersey and in Virginia. Forage crops,

soybeans, and grain for dairy cattle make up the largest acreage

of cropland. Forested areas, consisting mostly of farm woodlots,

are extensive on the steepest parts of the area. Some areas are

used for horticultural production, such as landscaping trees and

shrubs and Christmas trees, and some are used by the forest

products industry. Dairy farming, once a prominent activity, has

greatly diminished within the past 30 years. Horse and “hobby”

farms have become more numerous, particularly near the ruralsuburban fringe. Recreational uses, such as parks, athletic

fields, and golf courses, are common in or near areas of urban or

suburban development.

The major soil resource concern affecting this area is the

conversion of nonurban land, especially prime farmland, to

urban and suburban uses. Erosion and the resultant degradation

of stream quality commonly occur during construction

activities associated with urbanization. Other concerns are

erosion and degradation of soil quality in areas used for grain

crops year after year.

The important conservation practices on cropland are those

that reduce the hazard of erosion. They include contour

Figure 149A-1: Location of MLRA 149A in Land Resource Region S.

149A—Northern Coastal Plain

This area (shown in fig. 149A-1) is in Maryland (47

percent), New Jersey (44 percent), Pennsylvania (4 percent),

Delaware (3 percent), Virginia (1 percent), and the District of

Columbia (1 percent). It makes up about 5,205 square miles

(13,495 square kilometers). Interstate 95 corresponds broadly to

the north and west boundary of the MLRA from Maryland

through New Jersey. Major cities include Washington, DC, at

the southern edge of the MLRA and Baltimore, Maryland,

Wilmington, Delaware, East Brunswick, Trenton, Cherry Hill

(and many other cities across the Delaware River from

Philadelphia, Pennsylvania), and Vineland, New Jersey, at the

northern end. Part of the Fort Dix Military Reservation is in this

area in New Jersey. Aberdeen Proving Ground, the Fort George

G. Meade Military Reservation, the United States Naval

Academy in Annapolis, and the United States National

Agricultural Research Center in Beltsville, Maryland, are all in

the MLRA, as well as Andrews Air Force Base just east of

Washington, DC. There are some State forests and numerous

State parks, wildlife management areas, and national wildlife

refuges in this area.

farming, stripcropping, diversions, terraces, grassed waterways,

crop rotations, cover crops, and crop residue management.

Critical area planting, water- and sediment-control basins, and

urban storm-water management are important in the areas used

for urban development. 
490 Major Land Resource Areas

Physiography

This area is in the Embayed Section of the Coastal Plain

Province of the Atlantic Plain. This area is a nearly level to

rolling, dissected coastal plain that has been subjected to

episodes of rising and falling sea levels. During low sea levels,

eroding streams have dissected the area, leaving a series of

terraces across the landscape. The Raritan, Delaware, and

Chesapeake Bays are classic drowned river valleys. Elevation

ranges from sea level to 330 feet (100 meters). It is less than 165

feet (50 meters) in most of the area. Local relief is mostly 6 to

35 feet (2 to 10 meters), but it is 100 feet (30 meters) or more in

a few areas.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Delaware (0204), 41 percent; Upper Chesapeake (0206), 28

percent; Potomac (0207), 22 percent; and Lower Hudson-Long

Island (0203), 9 percent. The Delaware River separates

Pennsylvania and Delaware from New Jersey in this area. It

empties into the Delaware Bay. The Susquehanna River empties

into the northern tip of the Chesapeake Bay in the area. The

Raritan Bay marks the northern limit of the MLRA. The

Potomac River separates the District of Columbia and

Maryland from Virginia at the south tip of the area. The

Anacostia, Patuxent, and Severn Rivers in Maryland and the

Great Egg Harbor and Maurice Rivers in New Jersey are

designated as National Wild and Scenic Rivers.

Geology

Most of this area is underlain by unconsolidated sand, silt,

and clay sediments deposited in the near-shore environment of

late Cretaceous seas. The rise and fall of sea level resulted in

sand deposits separated by layers of clay and silt. High winds

during periods of maximum glacial advance redeposited some

of the sandy and silty sediments downwind. In addition, these

sediments are sorted downwind from coarsest to finest and from

thickest to thinnest. The north and west boundary of this

MLRA almost parallels the “fall line” on the eastern seaboard.

The fall line separates the bedrock of the interior uplands and

the Coastal Plain. The Coastal Plain sediments are a source of

ground water for the large cities built just below the fall line in

this area. Southeast Maryland and New Jersey are covered by

unconsolidated gravel deposited in the Tertiary and reworked

by the Quaternary seas and erosion. This reworking left a

pebble line as a pedisediment marker that separates the older

deposits from the more recent eolian depositions. Glauconite is

a common mineral in many of the unconsolidated sediments in

the Northern Coastal Plain. Some gabbro, serpentite,

Precambrian metamorphic rocks, and Triassic red shale are

exposed along the extreme western edges of this area. The fall

line is irregular, so some of the crystalline rocks that occur west

of the fall line also occur in this area.

Climate

The average annual precipitation in this area is 40 to 47

inches (1,015 to 1,195 millimeters). Near the coast, most of the

precipitation falls as high-intensity, convective thunderstorms

in midsummer. The seasonal snowfall ranges from little or none

in the southern part of the area to 30 inches (75 centimeters) in

the northern part. The average annual temperature is 52 to 58

degrees F (11 to 14 degrees C). The freeze-free period averages

220 days and ranges from 190 to 250 days. Temperatures and

the length of the freeze-free period decrease from south to north

and from the coast inland.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 25.7%; ground water, 9.2%

Livestock—surface water, 0.2%; ground water, 0.2%

Irrigation—surface water, 0.9%; ground water, 0.8%

Other—surface water, 56.4%; ground water, 6.5%

The total withdrawals average 2,640 million gallons per day

(9,990 million liters per day). About 17 percent is from ground

water sources, and 83 percent is from surface water sources.

Precipitation, perennial streams, and aquifers provide an

abundance of water in this area. In most years, moisture is

deficient in the coarse textured, well drained soils and

irrigation water from streams, ponds, and wells is used for highvalue crops. The surface water is suitable for almost all uses in

this area. Reservoirs on the Potomac and Upper Chesapeake

tributary streams supply water to the District of Columbia, and

the reservoirs on the Upper Chesapeake also supply Baltimore

and its suburbs with drinking water.

All of the ground water used in the urbanized corridor

running along the north and west edges of this area comes from

the unconsolidated sand and gravel in the Coastal Plain aquifer

system. Some of these aquifers are the Potomac, Raritan,

Magothy, Atlantic City 800-foot sand, Englishtown, and the

Kirkwood-Cohansey. Domestic supplies are obtained mainly

from shallow wells, but large supplies must be obtained from

deep wells. Generally, very little treatment is required before

the water from this aquifer system is used. The water is typically

soft, but it can be moderately hard to very hard in some areas.

The level of total dissolved solids is generally 100 to 200 parts

per million (milligrams per liter). The level of iron may exceed

the drinking water standard. The rocks in this aquifer system

dip to the east and become thicker towards the ocean. Water

from wells drilled closer to the ocean may have high levels of

chloride because of seawater intrusion. Since this aquifer

system is at or very near the surface throughout this area, the

water is highly susceptible to contamination from land use

activities.
of the United States 491

Soils

The dominant soil order in this MLRA is Ultisols. Some

Entisols, Inceptisols, Spodosols, and Histosols also occur. The

soils in this area have a mesic soil temperature regime, an aquic

or udic soil moisture regime, and mixed, siliceous, or

glauconitic mineralogy. They are very deep, excessively

drained to very poorly drained, and primarily loamy or sandy.

Some Hapludults formed in fluviomarine deposits on terraces

and flats (Downer, Hammonton, Sassafras, and Woodstown

series) and in near-shore marine deposits containing glauconite

on uplands (Adelphia, Freehold, Collington, and Holmdel

series). Other Hapludults formed in sandy eolian deposits

(Galestown and Tinton series) and in silty loess deposits

(Matapeake and Mattapex series). Fragiudults formed in old

alluvium on hills and relict stream terraces (Aura series) and in

silty deposits on broad flats (Beltsville series).

Quartzipsamments (Evesboro and Lakehurst series) formed in

eolian or marine sand deposits on dunes and flats along

streams. Haplosaprists (Manahawkin series) formed in

freshwater bogs and along stream corridors, and Sulfihemists

(Transquaking series) formed in organic deposits in estuarine

and tidal marshes. Alaquods (Atsion series) formed in sandy

marine deposits on braided stream channels and broad lowlying flats.

Biological Resources

This area supports pine and hardwoods. Loblolly pine,

Virginia pine, shortleaf pine, southern red oak, black oak,

scarlet oak, pin oak, willow oak, northern red oak, black

walnut, yellow-poplar, sweetgum, and red maple are the

dominant species.

Some of the major wildlife species in this area are whitetailed deer, cottontail, squirrel, waterfowl, and songbirds.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 13%

Grassland—private, 3%

Forest—private, 25%; Federal, 2%

Urban development—private, 32%

Water—private, 18%; Federal, 1%

Other—private, 6%

About half of this area is in farms. Nearly one-third of the

area is used for urban development. The extent of urban

development is expanding rapidly. The major crops in the area

are vegetables, corn, soybeans, small grains, and fruits. Tobacco

is a specialty crop in Maryland. Specialty crops in New Jersey

are highbush blueberries and cranberries. Forage crops and

grains for dairy cattle are important locally. Poultry, nursery

stock, and sod farms also are important locally. Most of the

149B—Long Island-Cape Cod Coastal

Lowland

This area (shown in fig. 149B-1) is in New York (65 percent),

Massachusetts (34 percent), and Rhode Island (1 percent). It

makes up about 2,110 square miles (5,465 square kilometers). It

includes New York City and Long Island, New York; Cape Cod,

Martha’s Vineyard, Nantucket Island, East Falmouth, Hyannis,

and South Yarmouth, Massachusetts; and Block Island, Rhode

Island. Numerous extensions of interstate highways occur at the

western end of Long Island, in the city of New York. Numerous

State parks and national wildlife refuges occur in this area. Fire

Island National Seashore in New York and Cape Cod National

Seashore and Martha’s Vineyard State Forest in Massachusetts

are in the area. The Poosepatuck and Shinnecock Indian

Reservations are on Long Island, and the Otis Air National

Guard Base is on Cape Cod. The Brookhaven National

Laboratory, a Naval Weapons Industrial Reserve Plant, and the

Plum Island Animal Disease Center are on Long Island. The

Woods Hole Oceanographic Institute is on Cape Cod.

Physiography

This area is in the Embayed Section of the Coastal Plain

Province of the Atlantic Plain. It is part of the partially

woodland in the area is in farm woodlots, but some is in large

holdings. Pine pulpwood and hardwood lumber are the

principal forest products. State forests and parks are extensive

in some areas. A narrow band along the coast is intensively

developed for resorts and for recreation.

The major soil resource concern affecting this area is the

conversion of nonurban land, especially prime farmland, to

urban and suburban uses. Erosion and the resultant degradation

of stream quality commonly occur during construction

activities associated with urbanization. Other concerns are

erosion and degradation of soil quality in areas used for grain

crops year after year. Improved drainage is needed on almost

one-fourth of the farmland.

The important conservation practices on cropland are those

that reduce the hazard of erosion. They include crop residue

management (including no-till and minimum tillage systems),

conservation cover crops, nutrient management, grassed

waterways, filter strips, and riparian buffers. Where livestock or

poultry are part of the farm operation, management of animal

waste, including storage of the waste, is important. Farmland

preservation programs are vital to maintaining the agricultural

resources in the area. Critical area planting, water- and

sediment-control basins, and urban storm-water management

are important in the areas used for urban development. 
492 Major Land Resource Areas

submerged coastal plain of New England. It is mostly an area of

nearly level to rolling plains, but it has some steeper hills

(glacial moraines). Ridges border the lower plains. Elevation

generally ranges from sea level to 80 feet (0 to 25 meters), but it

is as much as 330 feet (100 meters) in a few areas. Local relief is

mainly 3 to 30 feet (1 to 10 meters), but it is as much as 65 feet

(20 meters) in the more hilly areas.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Lower Hudson-Long Island (0203), 65 percent, and

Massachusetts-Rhode Island Coastal (0109), 35 percent. The

Peconic and Carmans Rivers are on the eastern end of Long

Island. The parts of this area in Massachusetts and Rhode Island

have no major rivers.

Geology

This entire area is made up of deep, unconsolidated glacial

outwash deposits of sand and gravel. A thin mantle of glacial

till covers most of the surface. Some moraines form ridges and

higher hills in this area of generally low relief. Sand dunes and

tidal marshes are extensive along the coastline.

Climate

The average annual precipitation in this area is 41 to 48

inches (1,040 to 1,220 millimeters). The precipitation is fairly

evenly distributed throughout the year. Rainfall occurs as highintensity, convective thunderstorms during the summer. The

seasonal snowfall is moderate to low in winter, and extended

periods of no snow cover can be expected in winter because of

relatively moderate temperatures. The average annual

temperature is 49 to 54 degrees F (10 to 12 degrees C). The

freeze-free period averages 220 days and ranges from 195 to

240 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 8.2%; ground water, 80.2%

Livestock—surface water, 0.0%; ground water, 0.3%

Irrigation—surface water, 0.2%; ground water, 3.8%

Other—surface water, 1.4%; ground water, 6.0%

The total withdrawals average 640 million gallons per day

(2,420 million liters per day). About 90 percent is from ground

water sources, and 10 percent is from surface water sources.

Most of the water used in this area is for public supply for the

urban population on Long Island. The area has only a few

perennial streams, rivers, and lakes, so ground water supplies

are used for most needs. In most years precipitation is adequate

for crops. High-value vegetable crops grown on the drier sandy

soils usually require irrigation for optimum yields. The surface

water is generally of good quality. Coastal inlets and bays

provide many opportunities for recreation and transportation.

The deep sand and gravel deposits underlying most of this

area are excellent aquifers and are good sources of irrigation

water and drinking water. The Magothy and Lloyd Sand make

up the Coastal Plain aquifer in the middle and east end of Long

Island and in Massachusetts and Rhode Island. This aquifer

does not occur on the west end of Long Island, where most of

the urban population resides. The water from this aquifer is soft

and typically has 80 to 200 parts per million (milligrams per

liter) total dissolved solids. Some of the water has high levels of

iron and manganese, but the median level of these constituents

is below the primary and secondary standards for drinking

water. The level of nitrates is somewhat high, 2.4 to 4.2 parts

per million (milligrams per liter). Encroachment of saltwater

from the surrounding ocean is a continuing hazard in these

freshwater aquifers. The ground water on Cape Cod and the

offshore islands is acidic and may cause corrosion of metal

pipes and concrete.

Soils

The dominant soil orders in this area are Inceptisols and

Entisols. The dominant suborders are Ochrepts and Psamments.

The soils in the area have a mesic soil temperature regime, a

Figure 149B-1: Location of MLRA 149B in Land Resource Region S.
of the United States 493

udic soil moisture regime, and mixed mineralogy. They are

deep, moderately coarse textured or coarse textured, nearly

level to sloping, and well drained. Ochrepts are on outwash

plains, terraces, and remnant beach ridges underlain by deposits

of sand and gravel. Excessively drained Psamments are

extensive on sandy outwash plains and in the steeper areas.

Well drained and moderately well drained Ochrepts are in some

morainic areas dominated by glacial till. Somewhat poorly

drained and poorly drained Aquents and Aquepts are in low

areas and in drainageways. They are of small extent but are

important locally. Sand dunes and tidal marshes are extensive

along the coastline.

Biological Resources

This area supports hardwoods and softwoods. Extensive

areas of the oak-pitch pine forest are on the droughty, sandy

soils. Oak and beech-birch-sugar maple are two other potential

forest types. White pine and red pine grow in many areas.

Barberry and lowbush blueberry are common early succession

types in burned-over areas. In areas of sand dunes, American

beachgrass can occur on foredunes and a mixture of bayberry,

sassafras, and American holly can occur on the more protected

dunes.

Some of the major wildlife species in this area are whitetailed deer, fox, raccoon, cottontail, gray squirrel, pheasant,

woodcock, bobwhite quail, and waterfowl. The species of fish

in the area include marine fish and shellfish.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 4%

Grassland—private, 1%

Forest—private, 18%; Federal, 1%

Urban development—private, 45%; Federal, 3%

Water—private, 20%

Other—private, 8%

Almost half of this area is used for urban development, and

urban expansion is continuing. Almost one-fifth of the area is

forested. Recreational uses are extensive along shorelines. On

the cropland in the area, cash crops and vegetables, such as

potatoes, cauliflower, and cabbage, are particularly important.

In a few areas duck and poultry farms are important enterprises.

The major soil resource concerns are sheet and rill erosion,

the erosion and sedimentation caused by urban storm-water

runoff and urban development, maintenance of the content of

organic matter and productivity of the soils, and management

of soil moisture. Conservation practices on cropland generally

include systems of crop residue management (such as

conservation tillage), winter cover crops, rotations of annual

crops and grasses and legumes, contour farming, irrigation

water management, and compost facilities. Critical area

planting, water- and sediment-control basins, and urban stormwater management are important in the areas used for urban

development. 

495

Figure T-1: Location of Land Resource Region T.

T—Atlantic and Gulf Coast Lowland

Forest and Crop Region

This region (shown in fig. T-1) is in Texas (23 percent),

Louisiana (15 percent), North Carolina (14 percent), South

Carolina (12 percent), Georgia (12 percent), Florida (11

percent), Virginia (3 percent), Maryland (3 percent), New Jersey

(3 percent), Delaware (2 percent), Mississippi (1 percent), and

Alabama (1 percent). It makes up 92,630 square miles (240,055

square kilometers).

This is a region of coastal lowlands, coastal plains, and the

Mississippi River Delta on the Gulf coast and coastal lowlands,

coastal plains, drowned estuaries, tidal marshes, islands, and

beaches along the Atlantic coast. The region is mostly level to

gently sloping and has low relief. The climate is mostly

temperate to hot and humid. The average annual precipitation

is 42 to 54 inches (1,065 to 1,370 millimeters). It commonly

exceeds 65 inches (1,650 millimeters) along the Louisiana,

Mississippi, and Alabama coastlines. The region is generally

driest at the northern end along the Atlantic coast and wettest at

the southern end. The amount of precipitation is slightly higher

during fall and winter than during the rest of the year. Snowfall

occurs in the northern third of the region. The average annual

temperature is 58 to 65 degrees F (14 to 18 degrees C). The

freeze-free period ranges from 220 to 305 days, increasing in

length to the south.

The total withdrawals of freshwater in this region average

about 13,770 million gallons per day (52,120 million liters per

day). About 79 percent is from surface water sources, and 21

percent is from ground water sources. Abundant precipitation,

numerous perennial streams, and good aquifers provide ample

supplies of good-quality water for all uses in the region. Almost

three-fourths of the water used in this region is for municipal

supply, for industry, or for cooling thermoelectric power plants.

The soils in this region are dominantly Alfisols, Entisols,

and Ultisols, but Histosols and Spodosols are not uncommon.

The dominant suborders are Aqualfs, Aquents, Aquults,

Psamments, and Udults. Other important suborders are Aquods,

Udalfs, Uderts, and Saprists. The soils in the region typically

formed in alluvium on flood plains, in depressions, and on

terraces. They dominantly have a thermic soil temperature
496 Major Land Resource Areas

Figure T-2: Cotton in an area of Land Resource Region T.

regime, an aquic or udic soil moisture regime, and siliceous,

mixed, or smectitic mineralogy.

The native vegetation in most of this region is a mixture of

pines and hardwoods. Grass is more typical in the southwestern

end of this region. About 94 percent of the region is privately

owned. Most of the land is in large holdings and is used for the

production of lumber and pulpwood. Less than 10 percent of

this region is cropped (fig. T-2). The acreage of cropland is

limited primarily because of a high water table and the

frequency of flooding. Recreation is a major industry in this

coastal region. Significant deposits of salt in domes, natural

gas, and petroleum are buried beneath the surface all along the

Gulf coast. The Atlantic coast and parts of the Gulf coast are

very populous. The loss of wetlands, cropland, and forestland

to urban development is a resource concern near these highpopulation zones. Wind erosion, water erosion, maintenance of

the content of organic matter and productivity of the soils, and

management of soil moisture, salinity, and coastal flooding also

are major resource concerns. 
of the United States 497

Figure 150A-1: Location of MLRA 150A in Land Resource Region T.

150A—Gulf Coast Prairies

This area (shown in fig. 150A-1) is in Texas (83 percent) and

Louisiana (17 percent). It makes up about 16,365 square miles

(42,410 square kilometers). It includes the towns of Crowley,

Eunice, and Lake Charles, Louisiana, and Beaumont, Houston,

Bay City, Victoria, Corpus Christi, Robstown, and Kingsville,

Texas. Interstates 10 and 45 are in the northeastern part of the

area, and Interstate 37 is in the southwestern part. U.S.

Highways 90 and 190 are in the eastern part, in Louisiana. U.S.

Highway 77 passes through Kingsville, Texas. The Chase and

Kingsville Naval Air Stations are in this area. The Attwater

Prairie Chicken National Wildlife Refuge and the Fannin

Battleground State Historic Site are in the part of the area in

Texas. The area has a few State parks.

Physiography

This area is in the West Gulf Coastal Plain Section of the

Coastal Plain Province of the Atlantic Plain. It is characterized

by nearly level plains that have low local relief and are

dissected by rivers and streams that flow toward the Gulf of

Mexico. Elevation ranges from sea level to about 165 feet (0 to

50 meters) along the interior margin.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Central Texas Coastal (1210), 28 percent; Galveston Bay-San

Jacinto (1204), 22 percent; Louisiana Coastal (0808), 17

percent; Lower Colorado-San Bernard Coastal (1209), 13

percent; Nueces-Southwestern Texas Coastal (1211), 7 percent;

Lower Brazos (1207), 7 percent; Trinity (1203), 3 percent;

Neches (1202), 2 percent; and Sabine (1201), 1 percent. The

Beckwith and Calcasieu Rivers are in the eastern end of this

area, in Louisiana. The Sabine River forms the boundary

between Texas and Louisiana. From north to south, the Neches,

Trinity, San Jacinto, Brazos, San Bernard, Navidad, Lavaca,

Guadalupe, San Antonio, Nueces, and Agua Dulce Rivers cross

the part of this area in Texas.

Geology

This area is mostly a strip of land that is about 50 to 80 miles

(80 to 130 kilometers) wide and runs along the Gulf of Mexico.

The sedimentary rocks at the surface are of Pleistocene age.

They were laid down during the last 2 million years. The

deposits are deltaic and lagoonal clays and loams derived from

older rocks to the west. At the western edge of this area, mostly

within Texas, the sediments are older and more weathered and

contain more sands. At the eastern edge, mostly within

Louisiana, a cap of mixed loess and alluvium occurs on most

soils. The loess was derived from the flood plain along the

Mississippi River. Some Tertiary deposits occur along the

interior edge of this MLRA. The weight of the recent deposits

has caused them to tilt towards the Gulf of Mexico, so

successively older deposits crop out from the coastal edge to

the interior edge of the area. Salt domes, natural gas, and

petroleum deposits are commonly below the surface throughout

this area. Recent deposits of alluvial sand fill the valleys of the

Brazos and Trinity Rivers and the other large rivers in the area.

Climate

The average annual precipitation in the northern two-thirds

of this area is 45 to 63 inches (1,145 to 1,600 millimeters). It is

28 inches (710 millimeters) at the extreme southern tip of the

area and 30 to 45 inches (760 to 1,145 millimeters) in the

southwestern third of the area. The precipitation is fairly evenly

distributed, but it is slightly higher in late summer and

midsummer in the western part of the area and slightly higher in

winter in the eastern part. Rainfall typically occurs as moderateintensity, tropical storms that produce large amounts of rain

during the winter. The average annual temperature is 66 to 72

degrees F (19 to 22 degrees C). The freeze-free period averages

325 days and ranges from 290 to 365 days, increasing in length

to the southwest.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 8.5%; ground water, 6.0%

Livestock—surface water, 0.6%; ground water, 0.5%

Irrigation—surface water, 7.7%; ground water, 20.2%

Other—surface water, 53.6%; ground water, 2.8%
498 Major Land Resource Areas

The total withdrawals average 4,390 million gallons per day

(16,615 million liters per day). About 30 percent is from ground

water sources, and 70 percent is from surface water sources.

Rainfall and perennial streams provide abundant water that is

suitable for almost all uses. Water for irrigating rice is often

obtained from streams. The surface water also is used for

municipal and industrial supplies and for cooling

thermoelectric power plants. Treated sewage effluent from

upstream sources makes up a significant portion of the low flow

in the San Antonio River in this area. Urbanization and

industrial wastes are threatening the surface and ground water

supplies in the Houston area. Most of the soils must be drained

for optimum growth of general farm crops.

Ground water is abundant in the Gulf Coast aquifer system

in this area. The water from this system has a median level of

420 parts per million (milligrams per liter) total dissolved

solids and typically is moderately hard. This system provides

much of the domestic, public supply, and irrigation water used

in this area.

Soils

The dominant soil orders in this MLRA are Alfisols,

Mollisols, and Vertisols. The soils have a hyperthermic soil

temperature regime in the southwestern part of the area and a

thermic soil temperature regime in the northeastern part. The

soils in the MLRA generally have an ustic soil moisture regime

and smectitic mineralogy. Drainage ranges from well drained in

very gently sloping and gently sloping soils in convex areas to

very poorly drained in soils in enclosed depressions. Soils that

formed in early Pleistocene sediments, generally occurring

north of Interstate 10, are very deep and have a loamy surface

layer and subsoil and siliceous mineralogy. Soils that formed in

late Pleistocene sediments, generally occurring south of

Interstate 10, are very deep and have a loamy or clayey

surface layer and a clayey, very slowly permeable subsoil.

Aqualfs and Udalfs (Crowley, Aris, and Vidrine series) are

dominant in Louisiana and southeastern Texas. Uderts and

Udalfs (League, Lake Charles, Laewest, Hockley, Katy, and

Telferner series) are dominant in the eastern and central parts of

the area. Usterts and Ustolls (Banquete, Cranell, Orelia, and

Victoria series) are dominant in the western and southwestern

parts.

Biological Resources

This area was originally a natural grass prairie with

hardwood trees along the rivers and streams. Little bluestem,

Indiangrass, switchgrass, and big bluestem are the dominant

species. A few groves of live oak dot the landscape.

Some of the major wildlife species in this area are whitetailed deer, raccoon, opossum, rabbit, fox, coyote, squirrel,

armadillo, nutria, quail, and mourning dove. Migratory

waterfowl, such as ducks and geese, and neotropical migratory

songbirds winter in this area. The species of fish in the area

include bass, channel catfish, and bream.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 32%

Grassland—private, 39%; Federal, 1%

Forest—private, 5%

Urban development—private, 16%

Water—private, 5%

Other—private, 2%

Most of this area is in farms. Rice, soybeans, grain sorghum,

cotton, corn, and hay are the chief crops. About two-fifths of the

area is rangeland or pasture. The forested areas, consisting

chiefly of hardwoods, border the rivers and streams that cross

the MLRA. Urban development is rapidly expanding onto

agricultural land throughout the area.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and tilth

of the soils, and management of soil moisture. Increasing

salinity is a problem in some areas. Conservation practices on

cropland generally include systems of crop residue

management, which help to control erosion and maintain the

content of organic matter in the soils. Timely tillage and

planting can help to maintain tilth and the supply of soil

moisture. Conservation practices on pasture and rangeland

generally include prescribed grazing, fences, watering facilities,

and nutrient and pest management. 

150B—Gulf Coast Saline Prairies

This area is entirely in Texas (fig. 150B-1). It makes up

about 3,420 square miles (8,865 square kilometers). The towns

of Groves, Texas City, Galveston, Lake Jackson, and Freeport

are in the northern half of this area. The towns of South Padre

Island, Loyola Beach, Corpus Christi, and Port Lavaca are in

the southern half. Interstate 37 terminates in Corpus Christi,

and Interstate 45 terminates in Galveston. The Padre Islands

National Seashore, the Corpus Christi Naval Air Station, and a

number of national wildlife refuges and State recreation areas

are in this MLRA.

Physiography

This MLRA is in the West Gulf Coastal Plain Section of the

Coastal Plain Province of the Atlantic Plain. It is characterized

by nearly level to gently sloping coastal lowland plains

dissected by rivers and streams that flow toward the Gulf of

Mexico. Barrier islands and coastal beaches are part of this

MLRA. The lowest parts of the area are covered by high tides,
of the United States 499

Figure 150B-1: Location of MLRA 150B in Land Resource Region T.

and the rest are periodically covered by storm tides. Parts of the

area have been worked by wind, and the sandy areas have

gently undulating to irregular topography because of low

mounds or dunes. Broad, shallow flood plains are along streams

flowing into the bays. Elevation generally ranges from sea level

to about 10 feet (3 meters), but it is as much as 25 feet (8

meters) on some of the dunes. Local relief is mainly less than 3

feet (1 meter).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Central Texas Coastal (1210), 32 percent; Nueces-Southwestern

Texas Coastal (1211), 30 percent; Galveston Bay-San Jacinto

(1204), 28 percent; Lower Colorado-San Bernard Coastal

(1209), 9 percent; and Lower Brazos (1207), 1 percent. The Rio

Grande forms the international boundary between Texas and

Mexico at the southwestern end of this area. Many other major

rivers empty into the bays along the Gulf of Mexico in the area.

Some of these include the Agua Dulce, Nueces, Lavaca,

Navidad, San Bernard, Brazos, San Jacinto, and Neches Rivers.

The Trinity River enters Galveston Bay just outside this area.

The Guadalupe and San Antonio Rivers join just before

emptying into San Antonio Bay in the area. The Sabine River

empties into Lake Sabine just outside the northeastern tip of

the area.

Geology

This area is underlain entirely by unconsolidated fluvial and

marine sediments (the Beaumont Formation). Most of the

surface is covered by Pleistocene-age sand that has been

reworked by the wind into mounds and dunes. Recent deposits

of clay, silt, and fine sand form deltas in areas where major

rivers empty into saltwater bays. Salt domes, natural gas, and

petroleum deposits are buried deeply beneath this area.

Climate

The average annual precipitation is 45 to 57 inches (1,145

to 1,450 millimeters) in the northeastern half of this area, 26

inches (660 millimeters) at the extreme southern tip of the area,

and 30 to 45 inches (760 to 1,145 millimeters) in the rest of the

area. Precipitation is abundant in spring and fall in the

southwestern part of the area and is evenly distributed

throughout the year in the northeastern part. Rainfall typically

occurs as moderate-intensity, tropical storms that produce large

amounts of rain during the winter. The average annual

temperature is 68 to 74 degrees F (20 to 23 degrees C). The

freeze-free period averages 340 days and ranges from 315 to

365 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 80.4%; ground water, 0.0%

Livestock—surface water, 5.4%; ground water, 0.3%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 13.4%; ground water, 0.5%

The total withdrawals average 35 million gallons per day

(133 million liters per day). About 1 percent is from ground

water sources, and 99 percent is from surface water sources.

Rainfall is the source of water for pasture and range. A few

freshwater streams and rivers flow into the area from the north,

and many bays and small entrapments of salty water are

throughout the area. Much of the surface water is not suitable

for most uses because of mixing with seawater. Freshwater for

urban uses is typically piped in from outside the area.

This area has little fresh ground water. Water for livestock

comes mainly from dugout ponds or very shallow wells. The

only freshwater is very near the surface in areas where sandy

soils are high enough on the landscape to escape tidal

inundation and yet are recharged by rainfall. Strata close to the

surface in these soils can store the ground water and release it to

wells. The water in the Gulf Coast aquifer system under this

area is salty because of the intrusion of seawater.

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, Inceptisols, Mollisols, and Vertisols. The soils in the

area have a hyperthermic soil temperature regime. The soils in

the eastern and central parts of the area have an aquic or udic

soil moisture regime, and those in the western part have an

aquic or ustic soil moisture regime. Mineralogy is mixed or
500 Major Land Resource Areas

siliceous in sandy soils, mixed or siliceous in loamy soils, and

smectitic in clayey soils. The soils are very deep. Drainage

ranges from excessively drained in Psamments to very poorly

drained in Aqualfs and Aquents. Many of the soils are

appreciably saline. The Alfisols include Typic Natraqualfs

(Dietrich, Livia, Matagorda, and Narta series). The Entisols

include Quartzipsamments (Daggerhill and Greenhill series),

Udipsamments (Galveston series), Psammaquents (Mustang

series), and Fluvaquents (Veston series). The Inceptisols include

Halaquepts (Barrada series). The Mollisols include Haplaquolls

(Harris series). The Vertisols include Typic Natraquerts (Franeau

series), Typic Hapluderts (Francitas series), and Sodic

Haplusterts (Victine series).

Biological Resources

This area supports grassland vegetation. The more saline

soils support a plant community dominated by gulf cordgrass

and smaller amounts of little bluestem, switchgrass, seashore

saltgrass, inland saltgrass, bushy sea-oxeye, marshhay

cordgrass, rushes, sedges, and pickleweed. The less saline,

sandy soils support a plant community dominated by little

bluestem and lesser amounts of switchgrass, gulfdune

paspalum, and marshhay cordgrass.

Some of the major wildlife species in this area are whitetailed deer, alligator, javelina, raccoon, skunk, opossum,

jackrabbit, cottontail, armadillo, turkey, bobwhite quail, ducks,

geese, and mourning dove. The species of fish in the area

include channel catfish, yellow catfish, blue catfish,

largemouth bass, red fish, speckled trout, and flounder.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 6%

Grassland—private, 31%; Federal, 3%

Forest—private, 1%

Urban development—private, 7%

Water—private, 40%; Federal, 3%

Other—private, 9%

Most of the coastal part of this MLRA is in areas of water

where lowlands are inundated daily by tides. This part of the

area is used primarily for recreation. The inland part of the

MLRA is characterized by a natural grass prairie with hardwood

trees along the rivers and streams. Nearly all of the inland area

is in ranches or is used for recreation. More than 75 percent of

the inland area is native rangeland that supports mainly salttolerant plant species. A small acreage is used for coastal

bermudagrass pasture for beef cattle or for rice or grain

sorghum. Urban and recreational developments are expanding,

especially along the barrier islands in the central and southern

parts of the area.

The major soil resource concerns are wind erosion, water

erosion, maintenance of the content of organic matter and tilth

of the soils, and management of soil moisture. Salinity and

coastal flooding preclude crop production in most of the

MLRA. Conservation practices on rangeland generally include

prescribed grazing, fences, nutrient management, pest

management, pasture and hay planting, management of upland

wildlife habitat, and watering facilities. Conservation practices

on cropland generally include systems of crop residue

management, which help to control erosion and maintain the

content of organic matter in the soils. Timely tillage and

planting can help to maintain tilth and the supply of soil

moisture. 

151—Gulf Coast Marsh

This area (shown in fig. 151-1) is in Louisiana (95 percent),

Texas (4 percent), and Mississippi (1 percent). It makes up

about 8,495 square miles (22,015 square kilometers). The towns

of Gretna, Chalmette, and Marrero, Louisiana, and the city of

New Orleans, Louisiana, are in the eastern part of this MLRA.

The town of Port Arthur, Texas, is in the western part. Interstate

10 and U.S. Highway 90 cross the area. The New Orleans Naval

Air Station is in this MLRA. Fort Jackson, overlooking the

mouth of the Mississippi River, and the Jean Lafitte National

Historic Park and Preserve are in the MLRA. A number of

national wildlife refuges and State parks occur throughout this

area.

Physiography

Vermilion Bay splits this area into an eastern half and a

western half. The eastern half is in the Mississippi Alluvial

Plain Section of the Coastal Plain Province of the Atlantic

Plain. The western half is in the West Gulf Coastal Plain Section

of the same province and division. The land east of Vermilion

Bay, part of the Mississippi River Delta, has a ragged shoreline.

The land west of Vermilion Bay has a smoother shoreline. Low,

narrow sandy ridges characterize much of the area. There are

many rivers, lakes, bayous, tidal channels, and manmade

canals. Elevation generally ranges from sea level to about 7 feet

(2 meters). It is as much as 10 feet (3 meters) on beach ridges,

canal spoil banks, and natural levees and as much as 165 feet

(50 meters) on salt dome islands. Some areas that are protected

by levees have subsided below sea level.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Lower Mississippi (0809), 60 percent; Louisiana Coastal

(0808), 31 percent; Galveston Bay-San Jacinto (1204), 5

percent; Lower Mississippi-Lake Maurepas (0807), 2 percent;

Sabine (1201), 1 percent; and Pearl (0318), 1 percent. The
of the United States 501

Figure 151-1: Location of MLRA 151 in Land Resource Region T.

Sabine River forms the boundary between Texas and Louisiana

in this area, and the Beckwith and Calcasieu Rivers are at the

western end of the area, in Louisiana. Other rivers in the part of

the area in Louisiana include the Bayou Nezpique, Mermentau,

Vermilion, Bayou Teche, Atchafalaya, and Mississippi Rivers.

Geology

The surface of this area is primarily Mississippi River clay,

silt, and fine sand deposited over the past 2 million years. The

eastern half of the area, part of the Mississippi River Delta, is

underlain by a mixture of Recent alluvial material and

Pleistocene-age marine sediments. The area west of Vermilion

Bay is underlain by older alluvial and marine sediments. Salt

domes, natural gas, and petroleum deposits are below the

surface in this area.

Climate

The average annual precipitation in most of the eastern half

of this area is 60 to 65 inches (1,525 to 1,650 millimeters). It is

49 to 60 inches (1,245 to 1,525 millimeters) in most of the

western half. About 70 percent of the precipitation occurs

during the growing season. Rainfall typically occurs as postfrontal precipitation in the winter and heat-convection showers

and thundershowers in the spring and summer. In addition,

tropical storms can bring large amounts of rainfall. The average

annual temperature is 67 to 69 degrees F (19 to 21 degrees C).

The freeze-free period averages 325 days and ranges from 290

to 365 days, increasing in length from north to south.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 6.5%; ground water, 0.8%

Livestock—surface water, 3.9%; ground water, 0.8%

Irrigation—surface water, 7.6%; ground water, 0.8%

Other—surface water, 75.3%; ground water, 4.4%

The total withdrawals average 1,310 million gallons per day

(4,958 million liters per day). About 7 percent is from ground

water sources, and 93 percent is from surface water sources.

Most of the water used in this area is for public supply,

thermoelectric power plants, and industry in the northeast

corner. This area has many rivers, lakes, bayous, tidal channels,

and manmade canals. About one-half of the marsh is fresh, and

one-half is salty. Tidal channels allow free movement of salty

water from the Gulf of Mexico into the parts of this area

adjacent to the Gulf. Most of the area is susceptible to flooding

either by freshwater drained from lands adjacent to the marsh or

by saltwater from the Gulf of Mexico. Daily tides flood some

areas. High tides and storm surges resulting from hurricanes or

tropical storms can be as much as 10 feet (3 meters) above sea

level and can flood most of the area.

River water in this area is generally of poor quality and

requires treatment prior to human consumption. Contamination

by fecal coliform bacteria is high in some rivers, and sediment

problems from nonpoint sources and contamination by

industrial wastes can occur in all of the rivers. Most soils of this

area are very poorly drained, having a water table at or above

the surface most of the time.

Ground water is scarce east of Vermilion Bay, in the

Mississippi Delta. Fresh ground water is available in moderate

to large quantities from the Gulf Coast (Texas) and Chicot

(Louisiana) aquifer systems west of Vermilion Bay. The water

from these Pleistocene-age river deposits is hard, and its

median level of total dissolved solids is 300 to 450 parts per

million (milligrams per liter). Iron concentrations exceed the

national secondary standard for drinking water and approach

1,000 parts per billion (micrograms per liter) in some wells in

Louisiana.

Soils

The dominant soil orders in this MLRA are Entisols and

Histosols. The soils in the area dominantly have a hyperthermic

soil temperature regime, an aquic soil moisture regime, and

smectitic mineralogy. They generally are very deep, very

poorly drained, and clayey. Hydraquents (Bancker, Creole,

Larose, and Scatlake series) formed in clayey sediments in

coastal marshes. Haplosaprists formed in organic deposits over

alluvium (Allemands, Clovelly, and Lafitte series) or entirely in

organic deposits (Kenner and Timbalier series).
502 Major Land Resource Areas

Figure 152A-1: Location of MLRA 152A in Land Resource Region T.

Biological Resources

This area supports freshwater and saltwater marsh vegetation

consisting of grasses, sedges, rushes, and other plants.

Alligatorweed, spikerush, maidencane, cutgrass, and

bulltongue characterize the freshwater vegetation. Roseau,

common reed, bulltongue, and marshhay cordgrass characterize

the intermediate water vegetation. Marshhay cordgrass,

saltgrass, and Olney bulrush characterize the brackish water

vegetation. Saltgrass, marshhay cordgrass, smooth cordgrass,

and black needlerush are included in the saltwater vegetation.

Some of the major wildlife species in this area are whitetailed deer, alligator, nutria, raccoon, otter, muskrat, swamp

rabbit, cottontail rabbit, mink, mottled duck, bobwhite quail,

mourning dove, meadowlark, lark bunting, and crawfish.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 16%

Grassland—private, 6%

Forest—private, 8%

Urban development—private, 3%

Water—private, 33%

Other—private, 30%; Federal, 4%

Most of this area supports marsh vegetation and is used for

wildlife habitat. The area is almost treeless. Much of the area is

uninhabited. The area is in the fertile and productive estuarine

complex that supports the marine life of the Gulf of Mexico.

The area provides wintering ground for millions of migratory

ducks and geese and habitat for many fur-bearing animals and

for alligators. A significant acreage west of Vermilion Bay is

firm enough to support livestock and is grazed by cattle in

winter. A small acreage of freshwater marsh is drained by

pumping systems and is used for pasture or for rice.

The major resource concerns are determined by land use and

marsh type. Flooding is a major concern in New Orleans. The

concerns in areas of native marsh include maintenance of the

salinity level in the soils, ingress and egress of freshwater or

saltwater, and the content of organic matter in the soils. The

concerns on pasture and cropland include maintenance of the

content of organic matter and control of the salinity level in the

soils. Erosion caused by overland water from high rainfall or a

storm surge in the Gulf is a concern in areas where the native

vegetation has been altered.

Conservation practices on cropland include systems of crop

residue management, which help to control erosion and

maintain the content of organic matter in the soils. Timely

tillage and planting can help to maintain tilth and the supply of

soil moisture and control salinity. The practices on pasture

include prescribed grazing, brush and pest management,

prescribed burning, and watering facilities. Management of

upland and wetland wildlife habitat is needed. 

152A—Eastern Gulf Coast Flatwoods

This area (shown in fig. 152A-1) is in Florida (71 percent),

Mississippi (12 percent), Alabama (9 percent), and Louisiana (8

percent). It makes up about 9,860 square miles (25,555 square

kilometers). It includes Hammond and Covington, Louisiana;

Gulfport, Biloxi, and Pascagoula, Mississippi; Mobile,

Alabama; and Pensacola, Panama City, and Perry, Florida.

Pascagoula, Mississippi, is one of the great ship-building

centers of the world. Interstates 10, 12, 55, 59, and 65 and U.S.

Highway 90 are in this area. The De Soto National Forest and

the NASA National Space Technology Laboratories are in the

part of this area in Mississippi. The Olf Summerdale Naval

Military Reservation is in the part in Alabama. The San Marcos

de Apalache State Historical Site, Apalachicola National Forest,

and Gulf Islands National Seashore are in the part in Florida.

The Tyndall and Eglin Air Force Bases and Pensacola Naval Air

Station also are in the part in Florida. A number of national

wildlife refuges and State parks and a few State forests are

throughout this MLRA.

Physiography

Almost all of this area is in the East Gulf Coastal Plain

Section of the Coastal Plain Province of the Atlantic Plain. The

extreme southeast tip is in the Floridian Section of the same

province and division. This MLRA is a nearly level, low

coastal plain crossed by many large streams. The part of the

area in Florida has many lakes and ponds. Elevation ranges

from sea level to 80 feet (0 to 25 meters). Local relief is

generally 10 to 20 feet (3 to 6 meters).
of the United States 503

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Suwannee (0311), 31 percent; Choctawhatchee-Escambia

(0314), 18 percent; Apalachicola (0313), 14 percent;

Pascagoula (0317), 13 percent; Ochlockonee (0312), 10

percent; Mobile-Tombigbee (0316), 5 percent; Lower

Mississippi (0809), 4 percent; Lower Mississippi-Lake

Maurepas (0807), 3 percent; and Pearl (0318), 2 percent.

Reaches of four rivers in the part of this area in Louisiana have

been designated as National Wild and Scenic Rivers. These are

the Amite, Tangipahoa, Tchefuncte, and Bogue Chitto Rivers.

The Pearl River forms the boundary between Louisiana and

Mississippi in this area. The Escatawpa River joins the

Pascagoula River just before it empties into the Gulf of Mexico

in the part of this area in Mississippi. The Tombigbee and

Alabama Rivers join just outside this area to form the Mobile

River in Alabama. The Perdido River forms the boundary

between Alabama and Florida in this area. The major rivers that

cross the part of this area in Florida on their way to the Gulf of

Mexico are the Escambia, Yellow, Choctawhatchee,

Apalachicola, Ochlockonee, and Suwannee Rivers.

Geology

Pleistocene-age terraces consisting of ancient Mississippi

River deposits of unconsolidated fine sand, which grades to

coarser sand and gravel at depth, are at the surface in the

western end of this area, in Louisiana and Mississippi. The

Citronelle Formation is at the surface in most of the parts of this

area in Mississippi, Alabama, and the western panhandle of

Florida. This formation is a thin layer of silt, sand, and gravel

deposited by an ancient predecessor of the Mississippi River

during Pliocene time. A thin veneer of Pleistocene-age sand

covers the surface of this area farther to the east in Florida.

Limestone and dolomite of the Floridan aquifer lie just beneath

the sand in the rest of the area in Florida. Karst topography is

common in Florida. Recent silt, sand, and gravel deposits fill

the valleys along most of the major rivers in the area.

Climate

The average annual precipitation is 60 to 68 inches (1,525

to 1,725 millimeters) in most of the central part of this area. It is

47 to 60 inches (1,195 to 1,525 millimeters) in much of the area

in Louisiana and Florida. The minimum precipitation usually

occurs in the early and middle parts of autumn, increasing

moderately in winter and early spring. Lesser amounts occur in

May. The maximum precipitation usually occurs in summer. At

the eastern end of this area, in Florida, rainfall usually occurs as

high-intensity, convective thunderstorms in summer. In the rest

of the area, it typically occurs as moderate-intensity, tropical

storms that produce large amounts of rain in winter. The

average annual temperature is 64 to 71 degrees F (18 to 21

degrees C). The freeze-free period averages 300 days and ranges

from 250 to 350 days. It is longer closer to the Gulf of Mexico

and to the south in Florida.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 1.8%; ground water, 15.3%

Livestock—surface water, 0.5%; ground water, 1.4%

Irrigation—surface water, 0.1%; ground water, 0.0%

Other—surface water, 74.0%; ground water, 6.9%

The total withdrawals average 1,030 million gallons per day

(3,899 million liters per day). About 24 percent is from ground

water sources, and 76 percent is from surface water sources. The

abundant rainfall and the many perennial streams are important

sources of water. Generally, river water is suitable for most uses

with some treatment. Surface waters have been polluted by

municipal and industrial wastewater discharges and fecal

coliform bacteria. Some improvement in water quality has

occurred as communities and industries strive to clean their

wastewater before discharging it into nearby rivers or lakes.

Most of the surface water is used for municipal and industrial

supply and for cooling thermoelectric power plants.

Ground water is plentiful in this area but is affected by salt

in many areas near the coast. Soft ground water is obtained from

the Pleistocene terraces in Louisiana, Mississippi, and Alabama.

This water is generally low in total dissolved solids, but it may

be contaminated by septic systems. Where faults occur, brine

from salt-dome deposits can move up into the surface aquifers,

making the water too salty for most uses. Where the ground

water is not suitable, better quality water can be obtained from

river valley alluvium. River flows tend to recharge these

aquifers annually, so this water is usually suitable for most uses

with some treatment. Ground water is plentiful in the Citronelle

and Floridan aquifers, in the middle and eastern parts of this

area. This water is soft and hard, respectively, and is suitable for

most uses. Since these aquifers are close to the Gulf of Mexico,

intrusion of seawater is a constant problem.

Soils

The dominant soil orders in this MLRA are Alfisols, Ultisols,

Entisols, Spodosols, and Histosols. The soils in the area

dominantly have a thermic or hyperthermic soil temperature

regime, an aquic or udic soil moisture regime, and siliceous

mineralogy. They generally are deep or very deep; are

somewhat poorly drained to very poorly drained; and are

loamy, mucky, or sandy. Alaquods (Chaires and Leon series)

and Psammaquents (Scranton series) formed in sandy marine

sediments on flats and in depressions. Haplosaprists formed in

organic deposits in swamps and depressions (Dorovan and

Pamlico series) and in marshes and swamps (Lafitte and

Maurepas series). Sulfihemists (Handsboro series) and
504 Major Land Resource Areas

Figure 152B-1: Location of MLRA 152B in Land Resource Region T.

Sulfaquents (Axis series) formed in saltwater and brackish water

marshes. Quartzipsamments (Newhan and Corolla series) and

Psammaquents (Duckston series) formed on dunes and in

interdunal swales on barrier islands. Glossaqualfs (Guyton

series) and Hydraquents (Arat and Levy series) formed in

alluvium on flood plains. Endoaqualfs (Meadowbrook and

Wekiva series) and Albaqualfs (Tooles series) formed in loamy

marine sediments on flats and flood plains and in depressions.

Endoaquults (Myatt series) and Paleudults (Stough series)

formed in mixed fluvial and marine sediments on flats and

stream terraces. Paleaquults (Plummer and Bayou series) and

Paleudults (Escambia and Ocilla series) formed in loamy and

sandy sediments on marine terraces.

Biological Resources

This area supports pine forest vegetation and freshwater,

brackish water, and saltwater marsh vegetation. Longleaf pine

and slash pine are the major trees. Chalky bluestem,

Indiangrass, and several species of panicum make up the

understory. Palmetto, gallberry, and waxmyrtle are the

dominant woody shrubs. Roseau, common reed, bulltongue,

maidencane, cutgrass, and alligatorweed characterize the

freshwater and intermediate water vegetation. Marshhay

cordgrass, saltgrass, and Olney bulrush characterize the

brackish water vegetation. Saltgrass, marshhay cordgrass,

smooth cordgrass, and black needlerush are included in the

saltwater vegetation.

Some of the major wildlife species in this area are whitetailed deer, feral hog, gray fox, red fox, bobcat, raccoon, skunk,

opossum, otter, rabbit, squirrel, turkey, bobwhite quail, and

mourning dove. The species of fish in the area include

largemouth bass, channel catfish, bullhead catfish, bluegill,

redear sunfish, spotted sunfish, warmouth, black crappie, chain

pickerel, gar, bowfin, sucker, spotted trout, croaker, striped

mullet, flounder, and red drum.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 1.3%

Grassland—private, 1.9%

Forest—private, 55.6%; Federal, 11.5%

Urban development—private, 10.4%

Water—private, 12.0%; Federal, 3.0%

Other—private, 4.3%

Very little of this dominantly forested area is in farms. Much

of it is in large holdings owned by pulp and paper companies.

Pulpwood and lumber are the principal forest products. Some of

the forestland is grazed. Some areas are in State and national

forests or are used as game refuges or as military training sites.

Only a very small acreage is cropped or pastured. Corn,

peanuts, tobacco, and soybeans are the major crops.

The major soil resource concerns are water erosion,

maintenance of the content of organic matter and productivity

of the soils, surface compaction, and management of soil

moisture. Conservation practices on forestland generally

include forest stand improvement, forest trails and landings,

prescribed burning, riparian forest buffers, forest site

preparation, bedding, establishment of trees and shrubs, and

management of upland wildlife habitat. The most important

conservation practice on pasture is prescribed grazing. Overseeding of pastures with small grains and/or legumes during

winter commonly supplements forage production. Haying also

provides additional feed during the long winters. Conservation

practices on cropland generally include systems of crop residue

management, cover crops, crop rotations, water disposal,

subsoiling or deep tillage, pest management, and nutrient

management. Critically eroding areas and areas where animals

congregate must be monitored regularly and treated promptly. 

152B—Western Gulf Coast Flatwoods

This area (shown in fig. 152B-1) is in Texas (59 percent) and

Louisiana (41 percent). It makes up about 5,880 square miles

(15,240 square kilometers). It is just northeast of Houston,

Texas, and north of Lake Charles, Louisiana. The towns of

Kingwood, Texas, and Singer, Sulfur, and Oberlin, Louisiana,

are in this MLRA. Interstate 10 is just south of this area. The

Sam Houston National Forest and the Big Thicket National

Preserve are in the part of this area in Texas. The Sam Houston

Jones State Park is in the part in Louisiana.
of the United States 505

Physiography

This area is in the West Gulf Coastal Plain Section of the

Coastal Plain Province of the Atlantic Plain. The area is nearly

level to gently sloping and has low local relief. Elevation

ranges from 80 to 330 feet (25 to 100 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Louisiana Coastal (0808), 35 percent; Neches (1202), 25

percent; Sabine (1201), 19 percent; Galveston Bay-San Jacinto

(1204), 11 percent; and Trinity (1203), 10 percent. This area is

bisected by many small streams and rivers that run toward the

Gulf of Mexico. From west to east, these include the San

Jacinto, Trinity, Neches, Sabine, Beckwith, Calcasieu, and

Mermentau Rivers. The Calcasieu River, in the eastern part of

the area, has been designated as a National Wild and Scenic

River.

Geology

The entire area is underlain by unconsolidated clay, silt,

sand, and gravel deposited by ancient rivers in late Tertiary and

Quaternary time. Recent silt, sand, and gravel deposits fill the

valleys along most of the major rivers in the area.

Climate

The average annual precipitation in this area generally

ranges from 46 to 60 inches (1,170 to 1,525 millimeters),

increasing from west to east. It is as much as 64 inches (1,625

millimeters) in the extreme northeast corner of the area. The

precipitation is evenly distributed throughout the year but is

slightly higher in the eastern part during winter. Rainfall

usually occurs as moderate-intensity, tropical storms that can

produce large amounts of rain during fall and winter. The

average annual temperature is 66 to 68 degrees F (19 to 20

degrees C). The freeze-free period averages 290 days and ranges

from 265 to 320 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 3.9%; ground water, 2.2%

Livestock—surface water, 2.6%; ground water, 1.6%

Irrigation—surface water, 1.3%; ground water, 7.2%

Other—surface water, 76.3%; ground water, 4.7%

The total withdrawals average 760 million gallons per day

(2,875 million liters per day). About 16 percent is from ground

water sources, and 84 percent is from surface water sources.

Rainfall, perennial streams, and aquifers provide an abundance

of water. Most of the soils must be drained for optimum growth

of general farm crops. Reservoirs on the San Jacinto River

provide industrial and public supply water to the eastern end of

this area. Water diverted from the Sabine, Calcasieu, and

Mermentau Rivers is used for irrigating rice, for cooling

thermoelectric power plants, and for industrial purposes in the

suburbs of Lake Charles, Louisiana. Because of high levels of

fecal coliform bacteria, the Calcasieu River is one of

Louisiana’s most polluted rivers.

The unconsolidated sediments in this area are the primary

sources of ground water. The water is used as drinking water

and for industry and irrigation. The Gulf Coast aquifer system

in Texas has moderately hard water with 300 to 500 parts per

million (milligrams per liter) total dissolved solids. Soft water

can be found in this aquifer in wells deeper than 500 feet (150

meters). The Chicot aquifer in Louisiana is made up of

numerous beds of unconsolidated sand and gravel separated by

layers of clay. The water in this aquifer is hard and has a median

level of 350 parts per million (milligrams per liter) total

dissolved solids. High iron levels may require treatment before

this water is used for public supply.

Soils

The dominant soil orders in this MLRA are Alfisols and

Ultisols. The soils in the area dominantly have a thermic soil

temperature regime, an aquic or udic soil moisture regime, and

siliceous or smectitic mineralogy. They generally are very deep,

moderately well drained to very poorly drained, and loamy or

clayey. Glossaqualfs formed in loamy and clayey sediments on

stream terraces (Caddo and Evadale series), in loamy marine

sediments on uplands (Waller series), and in alluvium on flood

plains and stream terraces (Guyton series). Glossudalfs (Messer

series) formed in loamy marine sediments on mounds and

ridges. Vermaqualfs (Sorter series) formed in old alluvium on

uplands. Hapluderts (Kaman series) formed in alluvium on

flood plains. Paleudults (Kirbyville and Malbis series) formed

in loamy marine sediments on uplands.

Biological Resources

This area supports pine-hardwood forest vegetation

characterized by longleaf pine. Sweetgum, blackgum, post oak,

blackjack oak, and southern red oak are the principal hardwood

species. Hawthorns, myrtle, and shining sumac make up the

woody understory. Mid and tall grasses are dominant in open

areas. Little bluestem, pinhole bluestem, big bluestem,

switchgrass, and Indiangrass are the principal grasses. Longleaf

uniola, Virginia wildrye, Florida paspalum, beaked panicum,

and several low-growing panicums and paspalums are the

principal grasses in shady areas. Lespedezas, tickclover,

wildbeans, and several composites are the principal forbs in the

area.
506 Major Land Resource Areas

Some of the major wildlife species in this area are whitetailed deer, coyote, fox, nutria, raccoon, skunk, cottontail, gray

squirrel, fox squirrel, mink, armadillo, wood rat, white-footed

mouse, eastern harvest mouse, cotton mouse, golden mouse,

hispid cotton rat, hispid pocket mouse, marsh rice rat, turkey,

quail, and mourning dove. Other major species include

cottonmouth moccasin, broad-banded water snake, coral snake,

hognose snake, canebrake rattlesnake, pigmy rattlesnake,

copperhead, Louisiana milk snake, speckled kingsnake, rough

green snake, buttermilk snake, five-lined skink, broad-headed

skink, green anole, smooth softshell turtle, three-toed box

turtle, red-eared turtle, Mississippi mud turtle, marbled

salamander, smallmouth salamander, Fowler’s toad, East Texas

toad, spring peeper, eastern tree toad, northern cricket frog,

northern leopard frog, and bullfrog. The species of fish in the

area include spotted bass, largemouth bass, crappie, catfish,

bullhead, carp, and bluegill.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 1%

Grassland—private, 12%; Federal, 1%

Forest—private, 74%; Federal, 3%

Urban development—private, 7%

Water—private, 1%

Other—private, 1%

The forestland in this area consists principally of pine and

pine-hardwood forests. Much of the forested acreage is owned

by large corporations, and lumber and pulpwood are the chief

forest products. Cleared areas are used mostly for pasture.

The major pasture grasses are bahiagrass and coastal

bermudagrass. Only a few small areas are used for crops.

Many small subdivisions are being developed throughout the

area, especially in the vicinity of Houston and Beaumont,

Texas.

The major soil resource concerns are water erosion,

maintenance of the content of organic matter and productivity

of the soils, and soil moisture management. When areas are bare

after a tree harvest, water erosion is a hazard on sloping land.

Conservation practices on forestland generally include forest

stand improvement, forest trails and landings, prescribed

burning, riparian forest buffers, forest site preparation, bedding,

establishment of trees and shrubs, and management of upland

wildlife habitat. The soils in this area are low in content of

organic matter and productivity. Measures that increase the

content of organic matter are needed. Applications of lime in

areas of low pH help to maintain or improve productivity.

Many of the soils remain wet or have a high water table for

some or most of the time during the year. Measures that

improve drainage or adapt the land use to the wet conditions

are needed. 

153A—Atlantic Coast Flatwoods

This area (shown in fig. 153A-1) is in South Carolina (30

percent), North Carolina (29 percent), Georgia (28 percent),

Florida (10 percent), and Virginia (3 percent). It makes up about

28,720 square miles (74,420 square kilometers). It includes

Suffolk and Franklin, Virginia; Greenville, Kinston, New Bern,

Jacksonville, and Wilmington, North Carolina; Florence,

Summerville, and Orangeburg, South Carolina; Fort Stewart,

Hinesville, and Waycross, Georgia; and Lakeside and

Jacksonville, Florida. Interstates 10, 16, 26, and 40 cross this

area. The Green Swamp Private Preserve, the Croatan National

Forest, Moores Creek National Military Park, and Camp

Lejeune Marine Corps Military Reservation are in the part of

this area in North Carolina. The Francis Marion National Forest

is in the part in South Carolina. The Osceola National Forest

and Camp Blanding, Cecil Field, and Jacksonville Naval Air

Stations are in the part in Florida. The west edge of the Great

Dismal Swamp in southeast Virginia and northeast North

Carolina and parts of the Okefenokee Swamp in Georgia and

Florida are in this MLRA.

Physiography

This area is in the Coastal Plain Province of the Atlantic

Plain. Almost three-fourths of the area is in the Sea Island

Section of the province, the northern end is in the Embayed

Section, the extreme southern end is in the Floridian Section,

and part of the southwest corner is in the East Gulf Coastal

Plain Section. This area is a relatively flat coastal plain crossed

by many broad, shallow valleys that have widely meandering

Figure 153A-1: Location of MLRA 153A in Land Resource Region T.
of the United States 507

stream channels. Some short, steep slopes border the stream

valleys. Elevation ranges from 25 to 165 feet (8 to 50 meters).

Local relief is mainly less than 35 feet (10 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Altamaha-St. Marys (0307), 18 percent; Pee Dee (0304), 17

percent; Edisto-Santee (0305), 16 percent; Suwannee (0311),

12 percent; Neuse-Pamlico (0302), 9 percent; ChowanRoanoke (0301), 9 percent; Cape Fear (0303), 9 percent;

Ogeechee-Savannah (0306), 6 percent; St. Johns (0308), 3

percent; and Lower Chesapeake (0208), 1 percent. Some of the

major rivers that cross this area on their way to the Atlantic

Ocean are, from north to south, the Blackwater, Nottoway,

Chowan, Roanoke, Tar, Pamlico, Neuse, Cape Fear, Little Pee

Dee, Pee Dee, Lynches, Black, Santee, Cooper, Edisto,

Combahee, Coosawhatchie, Savannah, Ogeechee, Altamaha,

Big Satilla, Satilla, and Suwanee Rivers.

Geology

Mostly unconsolidated Coastal Plain sediments occur at the

surface throughout this area. These sediments are primarily

Tertiary to Quaternary in age. They are a mixture of river-laid

sediments in old riverbeds and on terraces, flood plains, and

deltas. These young sediments are made up of combinations of

clay, silt, sand, and gravel. From central North Carolina to

Florida, Cretaceous marine, near-shore shale, sandstone, and

limestone deposits occur beneath the surface. Swamps were

common in this area prior to agricultural development. The

present-day river valleys are extensive and are flat near the

coast. The water table typically is close to the surface in these

river valleys. Soils having restricted drainage are common

throughout the area.

Climate

The average annual precipitation in this area is 44 to 57

inches (1,120 to 1,450 millimeters). The maximum

precipitation occurs in summer. Rainfall usually occurs as

moderate-intensity, tropical storms that can produce large

amounts of rain during fall and winter. Snowfall may occur in

the northern third of the area. The average annual temperature

is 58 to 69 degrees F (15 to 21 degrees C), increasing to the

south. The freeze-free period averages 290 days and ranges

from 210 to 365 days, increasing in length to the south.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 3.7%; ground water, 7.6%

Livestock—surface water, 1.5%; ground water, 0.4%

Irrigation—surface water, 2.4%; ground water, 2.2%

Other—surface water, 68.5%; ground water, 13.6%

The total withdrawals average 2,695 million gallons per day

(10,200 million liters per day). About 24 percent is from ground

water sources, and 76 percent is from surface water sources.

Rainfall, perennial streams, and aquifers provide an abundance

of water. Many of the soils require artificial drainage before

they can be used for crops, and some of the sandy soils require

irrigation during droughty periods. Most of the surface water

used in this area is for cooling thermoelectric power plants. The

numerous rivers that flow across the area have good-quality

water that is suitable for most uses with minimal treatment.

Water for domestic and some municipal and industrial uses

is obtained primarily from wells in the unconsolidated

sediments of the Coastal Plain aquifer system in the northern

end of this area. This water is moderately hard or hard but is

suitable for all uses. The median level of total dissolved solids

is generally less than 250 parts per million (milligrams per

liter). From central North Carolina to Florida, the principal

source of ground water is Cretaceous marine sediments. Water

from shale and sandstone aquifers is typically soft, and water

from limestone aquifers (Castle Haynes in South Carolina and

Floridan in South Carolina, Georgia, and Florida) is hard or

very hard. The median level of total dissolved solids is higher

than that in the water in the northern part of the area but is still

well below the national standard for drinking water. Since the

water in all of these aquifers is typically near the surface, nitrate

contamination is a problem in some areas. Naturally high levels

of fluoride and iron occur in some of the ground water

throughout the MLRA.

Soils

The dominant soil orders in this MLRA are Spodosols and

Ultisols. The soils in the area dominantly have a thermic soil

temperature regime, an aquic or udic soil moisture regime, and

siliceous or kaolinitic mineralogy. They generally are very

deep, well drained to very poorly drained, and loamy or clayey.

Paleaquults formed in marine sediments on flats and in

depressions on the coastal plain (Coxville, Lynchburg,

Pantego, and Pelham series) and on marine terraces (Rains

series). Paleudults (Goldsboro series) and Kandiudults (Norfolk

series) formed in marine sediments on uplands. Albaquults

(Leaf series) formed in mixed alluvium and marine sediments

on flats and terraces. Alaquods (Leon and Mascotte series)

formed in marine sediments on flats and terraces and in

depressions. Haplosaprists (Croatan series) formed in organic

deposits over mixed marine and fluvial deposits on the coastal

plain.

Biological Resources

This area supports pine-oak forest vegetation. Loblolly pine,

sweetgum, red maple, blackgum, and oaks are dominant in the

uplands. Water tupelo, swamp blackgum, bald cypress,

sweetgum, and red maple are dominant on the bottom land.
508 Major Land Resource Areas

Longleaf uniola, cutover muhly, toothachegrass, panicums,

little bluestem, and associated grasses and forbs characterize

the understory vegetation.

Some of the major wildlife species in this area are whitetailed deer, feral hog, gray fox, red fox, bobcat, raccoon, skunk,

opossum, otter, rabbit, armadillo, squirrel, turkey, and bobwhite

quail. The species of fish in the area include largemouth bass,

channel catfish, bullhead catfish, bluegill, redear sunfish,

spotted sunfish, warmouth, black crappie, chain pickerel, gar,

bowfin, and sucker.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 15%

Grassland—private, 2%

Forest—private, 61%; Federal, 6%

Urban development—private, 8%

Water—private, 4%

Other—private, 4%

Most of this area is in farms, but some is in national forests

or is used for game refuges or related purposes. Some of the

forests are farm woodlots, but most are large holdings.

Pulpwood is the main wood product. Lumber and naval stores

are other wood products. The acreage of cropland is somewhat

higher in the northern part of the area than in the southern part

and is considerably lower in Florida. Vegetable crops, fruits,

melons, sweet potatoes, and Irish potatoes are important crops.

Large acreages are used for corn, soybeans, wheat, and tobacco.

Some peanuts are grown on the sandy soils in Virginia, North

Carolina, and Georgia. Poultry farming is an important

enterprise in the northern part of the area and in some parts of

Florida. Swine operations are of major importance in North

Carolina and Virginia.

The major soil resource concerns are wind erosion and a

low soil conditioning index resulting from surface compaction

and a low content of organic matter in cultivated areas. Many

areas of poorly drained and very poorly drained soils on

uplands have been restored to wetland conditions. Wetland

restoration improves water quality and provides wildlife

habitat.

Conservation practices on forestland generally include

forest stand improvement, forest trails and landings, prescribed

burning, riparian forest buffers, forest site preparation, bedding,

establishment of trees and shrubs, and management of upland

wildlife habitat. Conservation practices on cropland generally

include crop residue management, establishment of field

borders, vegetative wind barriers, and nutrient and pest

management. 

153B—Tidewater Area

This area (shown in fig. 153B-1) is in North Carolina (35

percent), South Carolina (22 percent), Georgia (21 percent),

Virginia (17 percent), and Florida (5 percent). It makes up about

12,830 square miles (33,250 square kilometers). It includes the

cities or towns of Norfolk, Hampton, Chesapeake, Virginia

Beach, Chincoteague, and Kiptopeke, Virginia; Edenton,

Elizabeth City, Kitty Hawk, and Morehead City, North

Carolina; Socastee, Myrtle Beach, Mount Pleasant, Charleston,

and Hilton Head Island, South Carolina; Savannah, Brunswick,

and St. Simons Island, Georgia; and Yulee and Fernandina

Beach, Florida. Small sections of Interstates 26 and 64 are in

this area, and Interstate 95 parallels the coastline in the

southern third of the MLRA. The Colonial National Historic

Park, Oceana and Norfolk Naval Air Stations, Camp Peary, Fort

Eustis, Wallops Flight Center, and Langley Air Force Base are

in the part of this area in Virginia. The Croatan National Forest,

Camp Lejeune Marine Corps Base, the Wright Brothers

National Memorial, and the Cape Hatteras and Cape Lookout

National Seashores are in the part in North Carolina. The

Wright Brothers succeeded in the first powered flight near Kitty

Hawk, North Carolina, on the Outer Banks. Parris Island

Military Reservation, Fort Sumter and Fort Pulaski National

Monuments, and the eastern portion of the Francis Marion

National Forest are in the part of this area in South Carolina.

The Kings Bay Submarine Support Base, Fort Frederica

National Monument, and Cumberland Island National Seashore

Figure 153B-1: Location of MLRA 153B in Land Resource Region T.
of the United States 509

are in the part in Georgia. Numerous national wildlife refuges

are throughout this MLRA.

Physiography

Most of this area is in the Sea Island Section of the Coastal

Plain Province of the Atlantic Plain. The northern quarter is in

the Embayed Section of the same province and division. The

area is on a nearly level coastal plain crossed by many broad,

shallow valleys that have meandering stream channels. Most of

these valleys terminate in estuaries along the coast. Sea level is

rising, creating tidal marshes at the edges of the estuaries.

Elevation ranges from sea level to less than 25 feet (0 to 8

meters). Local relief is mainly about 3 feet (1 meter) or less.

The Suffolk Scarp is the upper (western) limit of this area.

The scarp marks a point where the ocean shore extended prior

to the Wisconsin period of glaciation. The eastern edge of the

area is characterized by a system of barrier and sea islands. The

barrier islands extend from the Eastern Shore of the Chesapeake

Bay in Virginia to north of Charleston, South Carolina. The

portion in North Carolina is referred to as the Outer Banks.

Large bodies of brackish water, such as the Pamlico and

Albemarle Sounds, are on the inland side of the barrier islands.

The sea islands extend from north of Charleston, South

Carolina, to Jacksonville, Florida.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Chowan-Roanoke (0301), 21 percent; Edisto-Santee (0305), 18

percent; Neuse-Pamlico (0302), 17 percent; OgeecheeSavannah (0306), 13 percent; Altamaha-St. Marys (0307), 12

percent; Lower Chesapeake (0208), 12 percent; Pee Dee (0304),

5 percent; Cape Fear (0303), 1 percent; and St. Johns (0308), 1

percent. Some of the major rivers that cross this area on their

way to the Atlantic Ocean are, from north to south, the

Rappahannock, York, Rivanna, and Nottoway Rivers;

Albemarle Sound (the Chowan and Roanoke Rivers); Pamlico

Sound (the Pamlico and Neuse Rivers); and the Cape Fear, Pee

Dee, Black, Santee, Cooper, Edisto, Combahee, Coosawhatchie,

Savannah, Ogeechee, Altamaha, Satilla, and St. Marys Rivers.

The headwaters of the St. Johns River are in this MLRA. The

Great Dismal Swamp is in the parts of the MLRA in Virginia

and North Carolina.

Geology

Mostly unconsolidated Coastal Plain sediments occur at the

surface throughout this area. These sediments are primarily

Tertiary to Quaternary in age. They are a mixture of river-laid

sediments in old riverbeds and on terraces, flood plains, and

deltas. These young sediments are made up of combinations of

clay, silt, sand, and gravel. The islands and coastline in this area

are covered with sand derived from these sediments. From

central North Carolina to Florida, Cretaceous marine, nearshore shale, sandstone, and limestone deposits occur beneath

the surface. Sea level has been rising since the last period of

continental glaciation, drowning the mouths of estuaries.

Swamps were common in this area prior to agricultural

development. The present-day river valleys are extensive and

are flat near the coast. The water table typically is close to the

surface in these river valleys. Soils having restricted drainage

are common throughout the area.

Climate

The average annual precipitation in this area is 40 to 58

inches (1,015 to 1,475 millimeters). The maximum

precipitation occurs in summer, and the minimum occurs in

autumn. Rainfall usually occurs as moderate-intensity, tropical

storms that can produce large amounts of rain during fall and

winter. Snowfall may occur in the northern end of the area. The

average annual temperature is 58 to 69 degrees F (14 to 21

degrees C). The freeze-free period averages 295 days and ranges

from 230 to 360 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 8.3%; ground water, 1.3%

Livestock—surface water, 0.4%; ground water, 0.2%

Irrigation—surface water, 0.2%; ground water, 0.1%

Other—surface water, 82.9%; ground water, 6.6%

The total withdrawals average 2,690 million gallons per day

(10,180 million liters per day). About 8 percent is from ground

water sources, and 92 percent is from surface water sources.

Rainfall, perennial streams, and aquifers provide an abundance

of water. Water for domestic, municipal, and industrial uses is

obtained mainly from wells. Many soils require artificial

drainage before they can be used for crops, but irrigation is

needed on some of the sandy soils during droughty periods.

Most of the surface water used in this area is for cooling

thermoelectric power plants and for industry. The numerous

rivers that flow into estuaries in the area have good-quality

water that is suitable for most uses with minimal treatment.

Water for domestic and some municipal and industrial uses

is obtained primarily from wells in the unconsolidated

sediments of the Coastal Plain aquifer system in Virginia. This

water is moderately hard or hard but is suitable for all uses. The

median level of total dissolved solids is generally less than 250

parts per million (milligrams per liter).

The part of this area in northeast North Carolina obtains

ground water from both a surficial aquifer and the Yorktown

aquifer. The only source of freshwater in the Outer Banks is the

surficial aquifer. The ground water in this aquifer is soft to hard

and has the same median level of total dissolved solids as the

water in the Coastal Plain aquifer in Virginia. Deeper wells or

wells that are excessively pumped, however, can provide water
510 Major Land Resource Areas

that has high levels of total dissolved solids because of the

encroachment of seawater. Water in the Yorktown aquifer has a

median level of total dissolved solids of 319 parts per million

(milligrams per liter) and is soft to hard.

From central North Carolina to Florida, the principal source

of ground water in this MLRA is Cretaceous marine sediments.

Water from shale and sandstone aquifers is typically soft, and

water from limestone aquifers (Castle Haynes in South Carolina

and Floridan in South Carolina, Georgia, and Florida) is hard or

very hard. The median level of total dissolved solids is higher

than that in the water in the northern part of the area but is still

well below the national standard for drinking water.

Since the water in all these aquifers is typically near the

surface, nitrate contamination is a problem in some areas.

Naturally high levels of fluoride and iron occur in some of the

ground water throughout this MLRA.

Soils

The dominant soil orders in this MLRA are Alfisols and

Entisols. Histosols are of lesser extent. The soils in the area are

characterized by restricted drainage, a thermic soil temperature

regime, and an aquic soil moisture regime. The soils in the

northern part of the area dominantly have mixed mineralogy,

and those in the southern part dominantly have mixed clay and

siliceous sand mineralogy. Very deep, loamy to clayey

Endoaquults (Tomotley, Yeopim, Yemassee, and Wahee series),

Umbraquults (Cape Fear and Portsmouth series), Endoaqualfs

(Argent and Yonges series), and Albaqualfs (Meggett series) are

extensive. Hapludults (Bertie and Tetotum series) are in the

higher areas where drainage is better but is somewhat restricted.

Other important soils are Alaquods (Leon and Lynn Haven

series) and Psamments (Wando, Newhan, Corolla, and Fripp

series). Histosols (Pungo and Belhaven series) are in large areas

in North Carolina and Virginia, in the Great Dismal Swamp and

in broad upland wetlands known as poquosins. Aquents

(Bohicket and Capers series) are extensive throughout the

brackish tidal marshes protected by the barrier islands and sea

islands.

Biological Resources

Loblolly pine and some oaks are dominant in the uplands in

this area, and blackgum, sweetgum, oaks, water tupelo, and

bald cypress are dominant on the bottom land. Longleaf pine

and slash pine are dominant in the southern part of the area.

Longleaf uniola, switchcane, panicums, little bluestem,

inkberry, large gallberry, greenbrier, waxmyrtle, cabbage palm,

and associated grasses and forbs characterize the understory.

Some of the major wildlife species in this area are black bear,

white-tailed deer, fox, raccoon, opossum, otter, muskrat, rabbit,

mink, squirrel, quail, and mourning dove. The red wolf, an

endangered species, is being reintroduced in several parts of the

area.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 11%

Grassland—private, 1%

Forest—private, 22%; Federal, 5%

Urban development—private, 9%

Water—private, 37%; Federal, 5%

Other—private, 10%

Most of the northern part of this area is in farms, but some is

in national forests or is used for game refuges, urban

development, or related purposes. Some of the forests in the

MLRA are in farm woodlots, but most are in large holdings.

Pulpwood is the main wood product. Lumber and naval stores

are other wood products. Large acreages are used for corn,

soybeans, tobacco, and vegetables. Recreational enterprises are

important in the area, and coastal marshes and open water in

sounds make up more than 40 percent of the area.

The major soil resource concerns are a seasonal high water

table and flooding. Measures that maintain drainage systems

are needed. Conservation practices on cropland generally

include crop residue management and control of the water

table. In much of the area, the water table can be controlled by

flashboard risers, which preserve water quality and utilize

ground water in lieu of irrigation. 

153C—Mid-Atlantic Coastal Plain

This area (shown in fig. 153C-1) is in Maryland (62 percent)

and Delaware (38 percent). It makes up about 2,015 square

miles (5,225 square kilometers). The town of Middletown,

Delaware, the city of Dover, Delaware, and the towns of

Chestertown and Easton, Maryland, are in this area. U.S.

Highways 13, 113, and 301 cross the area. Dover Air Force Base

is in this MLRA, and a number of national wildlife

management areas are throughout the MLRA.

Physiography

This area is in the Embayed Section of the Coastal Plain

Province of the Atlantic Plain. It is a nearly level to gently

sloping coastal plain. Elevation ranges from sea level to about

80 feet (0 to 25 meters). Local relief is only 6 to 15 feet (2 to 5

meters), even where flood plains or coves from the bay are

incised.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Upper Chesapeake (0206), 72 percent, and Delaware (0204), 28

percent. The Chester and Choptank Rivers are both impounded
of the United States 511

in the part of this area in Maryland. The Smyrna, Leipsic,

Murderkill, and St. Jones Rivers are in the part in Delaware.

Geology

This area is underlain by unconsolidated sand, silt, and clay

deposited by ancient rivers as continental sediments. Between

glacial periods, when sea level was much higher than it is

today, the river sediments were mixed with marine sediments. In

the northern part of the area, 1 to 3 feet (less than 1 meter) of

loess covers these sediments. Ocean levels are again rising, so

extensive tidal marshes are in areas along the Chesapeake and

Delaware Bays where the mouths of rivers are being further

submerged.

Climate

The average annual precipitation in this area is 40 to 44

inches (1,015 to 1,120 millimeters). Convective summer

thunderstorms provide a large amount of the total precipitation,

but precipitation is relatively evenly distributed throughout the

year. The average annual snowfall is typically about 6 inches

(15 centimeters). The average annual temperature is 54 to 58

degrees F (12 to 14 degrees C). The freeze-free period averages

220 days and ranges from 205 to 235 days. It is shorter inland

and longer along the bays.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 1.8%; ground water, 4.3%

Livestock—surface water, 0.1%; ground water, 0.5%

Irrigation—surface water, 2.2%; ground water, 4.5%

Other—surface water, 80.0%; ground water, 6.6%

The total withdrawals average 425 million gallons per day

(1,610 million liters per day). About 16 percent is from ground

water sources, and 84 percent is from surface water sources.

Rainfall, perennial streams, and ground water sources provide

an abundance of water. Many of the soils require artificial

drainage before they can be used for crops. During droughty

periods, however, irrigation is needed on some of the sandy

soils. The surface water is suitable for most uses. Most of the

surface water is used for cooling thermoelectric power plants.

Water for domestic, municipal, and industrial uses is

obtained mainly from wells. One aquifer consists of the

Quaternary and Tertiary alluvial deposits at the surface in

eastern Maryland and from the center of this area and south in

Delaware. The surficial sediments provide water that is soft and

that has less than 100 parts per million (milligrams per liter)

total dissolved solids. This water is used for domestic purposes

and some public supplies and is heavily pumped for irrigation.

The Chesapeake Group and Rancocas aquifers are sources of

ground water beneath the surficial aquifer. The water in these

aquifers has low levels of total dissolved solids, typically less

than 200 parts per million (milligrams per liter), but iron

concentrations typically exceed the secondary drinking water

standard of 300 parts per billion (micrograms per liter) and the

water is hard or very hard. These aquifers provide water for

public supply and for industry. The intrusion of seawater can be

a problem near the shorelines of the Chesapeake and Delaware

Bays.

Soils

The dominant soils in this MLRA are Ultisols. Entisols and

Inceptisols are of lesser extent. The soils in the area have an

aquic or udic soil moisture regime, a mesic soil temperature

regime, and mixed or siliceous mineralogy. They are very deep,

dominantly well drained to poorly drained, and generally

loamy or sandy in the mineral horizons.

Well drained, loamy Hapludults (Sassafras, Downer,

Hambrook, Unicorn, and Ingleside series) are on broad uplands.

Moderately well drained Hapludults (Woodstown, Pineyneck,

and Hammonton series) are in intermediate positions on the

landscape. Poorly drained Endoaquults (Fallsington,

Carmichael, and Hurlock series) are in low-lying areas. The

soils generally formed in loamy or sandy coastal plain

sediments. Significant areas of Hapludults (Matapeake,

Nassawango, and Mattapex series) and Endoaquults (Othello

and Elkton series) that formed in 1 to 3 feet (1 meter or less) of

loess over sandy and loamy, stratified coastal plain deposits

occur in the MLRA.

Small areas of sandy soils that formed in sandy terrace

Figure 153C-1: Location of MLRA 153C in Land Resource Region T.
512 Major Land Resource Areas

153D—Northern Tidewater Area

This area (shown in fig. 153D-1) is in New Jersey (46

percent), Maryland (35 percent), and Delaware (19 percent). It

makes up about 5,045 square miles (13,075 square kilometers).

The Chesapeake Bay and the Atlantic Ocean border this area.

The Delaware Bay divides the area nearly in half. The MLRA

includes Long Branch, Asbury Park, Lakewood, Hammonton,

and Atlantic City, New Jersey; Cambridge, Salisbury, and

Pocomoke City, Maryland; and Milford, Georgetown, and

Seaford, Delaware. A short stretch of Interstate 195 crosses the

northern tip of this area, in New Jersey. The Garden State

Parkway parallels the coast in the part of this area in New

Jersey, and the Atlantic City Expressway connects Atlantic City

to Philadelphia, Pennsylvania. U.S. Highway 13 connects most

of the rest of the area outside of New Jersey. Lakehurst Naval

Air Station and most of Fort Dix are in the part of this area in

New Jersey, and a number of national wildlife refuges and State

forests are throughout the area. The Assateague Island National

Seashore, consisting of most of Assateague Island, is in the part

of the area in Maryland.

deposits or ancient dunes associated with rivers are throughout

the MLRA. Somewhat poorly drained to excessively drained

Quartzipsamments (Evesboro, Runclint, Galloway, and Klej

series) and Hapludults (Galestown and Cedartown series) and

poorly drained Psammaquents (Askecksy series) are the

dominant soils in these small areas.

The flood plains, freshwater swamps, and low-lying flats are

dominated by very poorly drained Humaquepts (Mullica,

Indiantown, and Longmarsh series), Haplosaprists

(Manahawkin and Puckum series), and Fluvaquents (Chicone

and Zekiah series). The tidal marshes along the Chesapeake and

Delaware Bays are dominated by very poorly drained

Sulfihemists (Honga, Transquaking, Bestpitch, and Mispillion

series) and Sulfaquents (Appoquinimink and Broadkill series).

Biological Resources

The natural vegetation in this area consists mostly of white

oak, red oak, hickory, blackgum, red maple, black oak, scarlet

oak, chestnut oak, blackjack oak, sweetgum, loblolly pine,

beech, Virginia pine, scrub oak, highbush blueberry, sweet

pepperbush, greenbrier, laurel, sassafras, lowbush blueberry,

holly, and mountain laurel.

Some of the major wildlife species in this area are whitetailed deer, turkey, quail, raccoon, rabbit, squirrel, wading shore

birds, and numerous species of ducks and geese. The

Chesapeake and Delaware Bays provide habitat for diverse

populations of aquatic animal species. The Chesapeake Bay

provides extensive habitat for shellfish.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 40%

Grassland—private, 2%

Forest—private, 20%; Federal, 1%

Urban development—private, 7%

Water—private, 25%

Other—private, 5%

About one-half of this area is in farms. Farming is highly

diversified. The main agricultural enterprise is the production

of grain crops, such as soybeans and corn. Fruit and vegetable

production and specialty crops, such as cranberries and

blueberries, are important in the area. Many large-scale

corporate farms produce the specialty crops. The production of

poultry, truck crops, or fruit crops exceeds general farming in

importance in some counties. Sod farms are important in some

areas. Many large tracts of loblolly pine in areas of the wetter

soils are managed for timber production. Native mixed pine and

hardwood forests remain in large tracts or in areas of protected

public lands in State forests and parks. Broad flats of marine

and fluvial origin are drained by flat, wide, meandering, slowmoving streams. Ditch networks on large tracts have been

developed to facilitate drainage for agricultural production.

Rapid expansion of urban and suburban development is

reducing the extent of farmland, particularly prime farmland, as

well as forestland. The seafood industry is significant to the

economy of the counties bordering the two bays.

Several major soil resource concerns affect this area. The

most significant of these is the reduction in the acreage of

farmland and forestland caused by urban and suburban

development. Water erosion and the resultant degradation of

stream quality commonly occur during construction activities

associated with urbanization. Urbanization often changes the

character of agricultural communities, some of which have

histories dating back to the colonial era. Increased runoff

associated with urban development and agriculture commonly

causes stream downcutting and widening and the subsequent

deposition of sandy material along streambanks. Development

of residential lagoons along shorelines can severely impact the

adjacent wetlands and estuaries.

Farmland preservation programs are vital to maintaining the

agricultural resources in the area. Maintenance or improvement

of water quality for recreation and fishing is critical to local

economies, particularly in the shellfish habitat areas in the

Chesapeake Bay. Conservation practices on cropland generally

include systems of crop residue management (especially no-till

and minimum-till systems), conservation cover crops, nutrient

management, grassed waterways, filter strips, irrigation water

management, and riparian buffers. Where livestock or poultry

are part of the farm operation, management of animal waste,

including storage of the waste, is important. 
of the United States 513

sea level was much higher than it is today, the river sediments

in this area were mixed with underlying marine sediments.

During this period, major spits formed at the southern margin of

both the New Jersey and the Delmarva peninsulas. The

maximum elevation of these recently reformed areas is less than

20 feet (6 meters). In the part of this area in Maryland, 1 to 3

feet (1 meter or less) of loess covers these sediments. Ocean

levels are again rising; therefore, extensive areas of tidal marsh

are accreting and moving inland along the Chesapeake and

Delaware Bays and the Atlantic Ocean, particularly at the

mouths of rivers. Some areas of coastal beach dune sands are

along the ocean.

Climate

The average annual precipitation in most of this area is 38 to

45 inches (965 to 1,145 millimeters). It is 47 inches (1,195

millimeters) at the northern end of the area, in New Jersey.

Convective summer thunderstorms provide a large amount of

the total precipitation, but precipitation is relatively evenly

distributed throughout the year. The average annual snowfall is

typically about 6 inches (15 centimeters). The average annual

temperature is 52 to 59 degrees F (11 to 15 degrees C). The

freeze-free period averages 220 days and ranges from 190 to

255 days. It is shorter in inland areas and longer along the

Atlantic Ocean and the Chesapeake and Delaware Bays.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 3.4%; ground water, 43.2%

Livestock—surface water, 0.4%; ground water, 1.0%

Irrigation—surface water, 4.4%; ground water, 11.7%

Other—surface water, 7.9%; ground water, 27.9%

The total withdrawals average 265 million gallons per day

(1,005 million liters per day). About 84 percent is from ground

water sources, and 16 percent is from surface water sources.

Rainfall and perennial streams provide an abundance of water.

Ground water discharge from the surficial aquifer throughout

this area contributes to the perennial streamflows. Many of the

soils require artificial drainage before they can be used for

crops, but irrigation is needed on the sandier soils. The surface

water is generally suitable for most uses. Contamination from

agricultural runoff and municipal and industrial wastewater

discharges causes some local water-quality problems. Near the

coast, the surface water is brackish and is not used.

Water for domestic, municipal, and industrial uses and for

irrigation is obtained mainly from wells. The Coastal Plain

aquifers in this MLRA are primarily Quaternary and Tertiary

alluvial deposits at or very close to the surface. The surficial

aquifers are the Columbia, Unconfined, and KirkwoodCohansey. They provide water that is soft or moderately hard

Physiography

This area is in the Embayed Section of the Coastal Plain

Province of the Atlantic Plain. It is a nearly level to gently

sloping coastal plain with dunes and beaches on the ocean and

bay sides. Large areas of tidally flooded marshes occur,

particularly between the numerous barrier islands and the

mainland along the Atlantic Coast and along the bays.

Elevation typically ranges from sea level to about 80 feet (0 to

25 meters). In the Barnegate Bay watershed in the northern part

of the MLRA, however, remnants of old Coastal Plain deposits

have a maximum elevation of more than 200 feet (60 meters).

Local relief is only 6 to 15 feet (2 to 5 meters), even where

flood plains or coves from the bay are incised.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Upper Chesapeake (0206), 50 percent; Delaware (0204), 49

percent; and Lower Hudson-Long Island (0203), 1 percent.

From north to south, the major rivers in the area are the Shark,

Manasquan, Toms, Yellow, Oswego, Wading, Mullica,

Tuckahoe, Great Egg Harbor, and Maurice Rivers in New Jersey

and the Mispillion, Broadkill, Gravelly, Indian, Nanticoke,

Broad, Wicomico, Dividing, and Pokomoke Rivers in Delaware

and Maryland. The Mullica River in New Jersey and the

Pokomoke River in Maryland have been designated as

National Wild and Scenic Rivers.

Geology

This nearly level to gently sloping coastal plain is made up

of unconsolidated sand, silt, and clay deposited by ancient

rivers as continental sediments. Between glacial periods, when

Figure 153D-1: Location of MLRA 153D in Land Resource Region T.
514 Major Land Resource Areas

and that typically has less than 100 parts per million

(milligrams per liter) total dissolved solids. High levels of iron

cause some problems for users throughout the MLRA. Since

these are water-table aquifers, they are very susceptible to

contamination from surface activities. Excessive withdrawals of

ground water can result in the intrusion of seawater near the

Delaware and Chesapeake Bays and on the coast of the Atlantic

Ocean. These aquifers provide water for public supply and for

industry.

Aquifers lying beneath the surficial aquifers are known as

the Chesapeake Group. Their water has low levels of total

dissolved solids (typically less than 200 parts per million

(milligrams per liter), but iron concentrations typically exceed

the secondary drinking water standard of 300 parts per billion

(micrograms per liter). Also, the water is hard or very hard.

These aquifers provide water for public supply and for industry.

Soils

The dominant soil orders in this MLRA are Ultisols.

Entisols, Histosols, Spodosols, and Inceptisols are of lesser

extent. The soils in the area have a mesic soil temperature

regime, an aquic or udic soil moisture regime, and mixed or

siliceous mineralogy. They are very deep, very poorly drained

to excessively drained, and generally loamy or sandy in the

mineral horizons. A strip of coastal beach dune sand extends

along the Atlantic Ocean in most of the MLRA.

Well drained, loamy Hapludults (Sassafras, Downer,

Hambrook, Nassawango, and Ingleside series) are on broad

uplands. Moderately well drained Hapludults (Woodstown and

Hammonton series) are in intermediate positions on the

landscape. Poorly drained Endoaquults (Fallsington and

Hurlock series) are in low-lying areas. These soils generally

formed in loamy or sandy coastal plain sediments. The parts of

the MLRA in Maryland and Delaware have significant areas of

Hapludults (Matapeake and Mattapex series) and Endoaquults

(Othello and Elkton series) that formed in 1 to 3 feet (1 meter or

less) of loess over sandy and loamy, stratified coastal plain

deposits. Large areas of sandy soils that formed in sandy coastal

plain sediments or ancient dunes are throughout the MLRA.

Somewhat poorly drained to excessively drained

Quartzipsamments (Evesboro, Runclint, Lakehurst, Lakewood,

and Klej series) and Hapludults (Galestown and Cedartown

series) and poorly drained and very poorly drained Alaquods

(Atsion and Berryland series) are the dominant soils.

The flood plains, freshwater swamps, and low-lying flats are

dominated by very poorly drained Humaquepts (Mullica

series), Haplosaprists (Manahawkin and Puckum series), and

Fluvaquents (Chicone series). The tidal marshes along the

Chesapeake and Delaware Bays and between the barrier islands

and the mainland are dominated by very poorly drained

Sulfihemists (Honga, Transquaking, Bestpitch, and Mispillion

series) and Sulfaquents (Appoquinimink, Broadkill, Purnell,

and Boxiron series).

Along the Atlantic Ocean, a broken line of barrier islands

consisting of primarily coastal beaches and dunes is dominated

by Udipsamments (Acquango and Brockatonorton series) and

Quartzipsamments (Hooksan series).

Biological Resources

The natural vegetation in this area consists mostly of pitch

pine, blackgum, red maple, black oak, scarlet oak, chestnut

oak, blackjack oak, Atlantic white cedar, sweetgum, white

oak, hickory, shortleaf pine, Virginia pine, scrub oak,

highbush blueberry, sheep laurel, sweet pepperbush, gallberry,

greenbrier, laurel, sassafras, lowbush blueberry, holly, and

mountain laurel.

Some of the major wildlife species in this area are whitetailed deer, turkey, quail, raccoon, rabbit, squirrel, wading shore

birds, and numerous species of ducks and geese. The

Chesapeake Bay provides extensive habitat for shellfish. Both

the Chesapeake and Delaware Bays provide habitat for diverse

populations of aquatic animal species.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 15%

Grassland—private, 1%

Forest—private, 31%; Federal, 2%

Urban development—private, 11%

Water—private, 28%; Federal, 1%

Other—private, 11%

This area consists mainly of forestland, open water, or

farmland. A significant acreage is urban land. The agricultural

products in the area are primarily grain crops, such as soybeans

and corn. Fruits and vegetables also are grown, and tobacco is

grown in some areas in Maryland. Cranberries and blueberries

are grown in New Jersey. Poultry production is important in the

parts of the area in Delaware and Maryland, and much of the

locally grown corn is used for feed. Large forested areas occur

throughout the MLRA, particularly in the wetter low-lying

areas. Numerous national wildlife refuges, State forests, State

parks, and wildlife management areas occur throughout the

MLRA. Seasonal tourism is a large part of the local economy,

particularly along or near the barrier islands.

Several major soil resource concerns affect this area. The

most important is the loss of farmland and forestland to urban

and suburban development. Water erosion and the resultant

degradation of stream quality commonly occur during the

construction activities associated with urbanization.

Urbanization often changes the character of agricultural

communities, some of which have histories dating back to the

colonial era. Increased runoff associated with urban

development and agricultural uses commonly causes stream

downcutting and widening and the subsequent deposition of
of the United States 515

sandy material along streambanks. Development of residential

lagoons along shorelines can have a severe impact on the

adjacent wetlands and estuaries.

Farmland preservation programs are vital to maintaining the

agricultural resources in this area. Maintenance or improvement

of water quality for recreation and fishing is critical to local

economies and is particularly important in the shellfish habitat

areas in the Chesapeake Bay. Conservation practices on

cropland generally include systems of crop residue

management (especially no-till and minimum-till systems),

conservation cover crops, nutrient management, grassed

waterways, filter strips, and riparian buffers. Where livestock or

poultry are part of the farm operation, management of animal

waste, including storage of the waste, is important. 

517

Figure U-1: Location of Land Resource Region U.

U—Florida Subtropical Fruit, Truck

Crop, and Range Region

This region is entirely in Florida (fig. U-1). It makes up

35,610 square miles (92,275 square kilometers).

This is a region of low, flat coastal plains. The climate is hot

and humid. The average annual precipitation is 44 to 59 inches

(1,120 to 1,500 millimeters). About 60 percent of the annual

precipitation occurs from June through September. Fall and

winter are drier. The average annual temperature is 70 to 75

degrees F (21 to 24 degrees C). In most of the region, the freezefree period ranges from 325 to 365 days.

The total withdrawals of freshwater in this region average

about 6,880 million gallons per day (26,040 million liters per

day). About 40 percent is from surface water sources, and 60

percent is from ground water sources. Abundant precipitation,

some streams, and good aquifers provide ample supplies of

good-quality water for all uses in this region. More than half of

the water used in this region is irrigation water. The rest is about

evenly split between public supply and municipal and

industrial uses.

The soils in this region are dominantly Entisols. The region

also has significant areas of Alfisols and Histosols. The

dominant suborders are Aqualfs, Aquents, and Psamments. The

soils in the region dominantly have a hyperthermic soil

temperature regime, an aquic or udic soil moisture regime, and

siliceous or carbonatic mineralogy.

About 90 percent of the land in this region is privately

owned. More than half of the region consists of swamps and

marsh. Only about 10 percent is cropland, which is used mainly

for citrus fruits (fig. U-2). Truck crops and some sugarcane are

important sources of income. Management of the water table is

important during the summer, but many crops may require some

irrigation during the generally dry fall and winter. The major

resource concerns are wind erosion, maintenance of the content
518 Major Land Resource Areas

Figure U-2: An orange grove in an area of Land Resource Region U.

of organic matter and productivity of the soils, and

management of soil moisture. Water quantity can be a problem

in a few parts of this region, and maintaining the quality of

surface water and ground water is a concern. 
of the United States 519

Figure 154-1: Location of MLRA 154 in Land Resource Region U.

154—South-Central Florida Ridge

This area is entirely in Florida (fig. 154-1). It makes up about

8,285 square miles (21,470 square kilometers). Parts of the east

side of the city of Tampa Bay and the west half of Orlando are

in this area. Interstate 75 parallels the north-south axis of the

northern half of this MLRA, and Interstate 4 crosses the

southern tip. The Ocala National Forest and the Withlacoochee

State Forest are in this area.

Physiography

This area is in the Floridian Section of the Coastal Plain

Province of the Atlantic Plain. The area is nearly level to gently

rolling. The land surface is very irregular because of the many

sinkholes that dot the area. Elevation is 80 to 165 feet (25 to 50

meters) in most of the area. It ranges from sea level along a

narrow strip on the western edge of the area to 330 feet (100

meters) on some hills.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Peace-Tampa Bay (0310), 46 percent; St. Johns (0308), 36

percent; Southern Florida (0309), 14 percent; and Suwanee

(0311), 4 percent. The Withlacoochee River is in this area.

Geology

This area is a young marine plain underlain by Tertiary-age

rocks, including very fine grained shale, mudstone, limestone,

and dolomite beds. A sandy marine deposit of Pleistocene age

overlies the limestone in most of the area. Phosphate is mined

from the limestone beds in the central part of the area.

Climate

The average annual precipitation in this area is 46 to 56

inches (1,170 to 1,420 millimeters). About 60 percent of the

precipitation occurs from June through September. Most of the

rainfall occurs as moderate-intensity, tropical storms that

produce large amounts of rain from late spring through early

autumn. Late autumn and winter are relatively dry. The average

annual temperature is 68 to 73 degrees F (20 to 23 degrees C).

The freeze-free period averages 335 days and ranges from 300

to 365 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 3.0%; ground water, 34.9%

Livestock—surface water, 0.1%; ground water, 0.7%

Irrigation—surface water, 9.8%; ground water, 23.8%

Other—surface water, 8.2%; ground water, 19.5%

The total withdrawals average 1,220 million gallons per day

(4,620 million liters per day). About 79 percent is from ground

water sources, and 21 percent is from surface water sources.

Rainfall and surface and ground water sources provide an

abundance of water. Many lakes are in the sinkholes

throughout the area, but the area has few perennial streams. The

risk of ground-water contamination is high because of the high

water table and the karst topography in this area.

Almost all domestic, municipal, and irrigation water is

obtained from wells in the Floridan aquifer in this MLRA. This

aquifer is one of the most productive ground water sources in

the United States. The water is hard but is of good quality.

Wells yield large quantities of calcium bicarbonate type water.

The Floridan aquifer is a thick sequence of Tertiary limestone

and dolomite. The Eocene Avon Park Formation and Ocala

Limestone are the thickest and most productive units in the

aquifer system.
520 Major Land Resource Areas

Soils

The dominant soil orders in this MLRA are Entisols and

Ultisols. The soils in the area dominantly have a hyperthermic

soil temperature regime, a udic soil moisture regime, and

siliceous mineralogy. They generally are very deep, excessively

drained to somewhat poorly drained, and loamy or sandy.

Paleudults (Arredondo, Millhopper, and Sparr series) formed in

loamy marine sediments on uplands. Quartzipsamments

(Astatula, Candler, Lake, and Tavares series) formed in mixed

sandy eolian and marine sediments on uplands.

Biological Resources

This area supports “sand hill” vegetation. Turkey oak,

bluejack oak, and longleaf pine are the major species. Running

oak, gopher apple, and such grasses as bluestems and panicums

characterize the understory.

Some of the major wildlife species in this area are deer, feral

hog, fox, raccoon, rabbit, gray squirrel, fox squirrel, turkey,

bobwhite quail, and dove. The species of fish in the area

include largemouth bass, shellcracker, catfish, bluegill bream,

and crappie.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 7%

Grassland—private, 23%

Forest—private, 28%; Federal, 4%

Urban development—private, 23%

Water—private, 7%; Federal, 2%

Other—private, 6%

The agricultural enterprises in this area include the

production of livestock, citrus, and truck crops. Forest products

also are important. The forested areas include the Ocala

National Forest. Pulpwood is the chief forest product, but some

lumber also is produced. Some of the forests are grazed.

Although less than one-tenth of the acreage is used for crops,

this is the major citrus-producing area in Florida. Many kinds

of winter vegetables also are grown. About half of the pastured

areas in the MLRA are improved and intensively managed.

Beef cattle are the principal kind of livestock, but dairying is

an important enterprise near some of the large cities. Urban land

makes up a large acreage in the area. Phosphate mines are a

prominent feature in the central part of the area.

The major soil resource concerns are wind erosion,

maintenance of the content of organic matter and productivity

of the soils, and management of soil moisture. Additional

resource concerns are water quality, water quantity (excess

amounts), and plant and animal productivity and health.

Conservation practices on cropland generally include

conservation crop rotations, cover crops, irrigation water

management (including microirrigation systems), nutrient

management, and pest management. Conservation practices on

pasture and rangeland generally include prescribed grazing,

brush management, pest management, prescribed burning, and

watering facilities. Conservation practices on forestland

generally include forest stand improvement, forest site

preparation, prescribed burning, firebreaks, establishment of

trees and shrubs, pest management, and management of upland

wildlife habitat. 

155—Southern Florida Flatwoods

This area is entirely in Florida (fig. 155-1). It makes up

about 18,575 square miles (48,135 square kilometers).

Numerous cities occur in this area. Gainesville and Ocala are

in the isolated northern part of the area. Daytona Beach, West

Palm Beach, and Fort Lauderdale are on the Atlantic coast,

which forms the eastern boundary of the area. The cities of

St. Petersburg and Fort Meyers and most of Tampa Bay are on

the western edge of the area, along the coast of the Gulf of

Mexico. The eastern half of the city of Orlando is in this

MLRA. Interstate 75 parallels the Gulf coast in the western

half of this MLRA, and Interstate 95 parallels the Atlantic

coast in the eastern half. Interstate 4 crosses the northern end

of both the eastern and western parts of this area. Cape

Canaveral and the John F. Kennedy Space Center are in this

MLRA.

Physiography

This area is in the Floridian Section of the Coastal Plain

Province of the Atlantic Plain. It is on a nearly level coastal

plain that has large areas of swamps and marshes. Streams and

lakes are common. The northwestern half of Lake Okeechobee

occurs in this area. Its surface is 14 feet (4 meters) above sea

level. Most of the area is flat, but some hummocks rise 3 feet (1

meter) above the general level of the landscape and low beach

ridges and dunes, on each coast, rise 6 to 10 feet (2 to 3 meters)

above the lower inland areas. Elevation ranges from sea level to

less than 80 feet (25 meters), increasing gradually from each

coast inland.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Southern Florida (0309), 40 percent; St. Johns (0308), 32

percent; Peace-Tampa Bay (0310), 27 percent; and Suwannee

(0311), 1 percent. The St. Johns, Kissimmee, and

Caloosahatchee Rivers are in this area.
of the United States 521

Figure 155-1: Location of MLRA 155 in Land Resource Region U.

Geology

This area is a young marine plain underlain by Tertiary-age

rocks, including very fine grained shale, mudstone, and

limestone beds. A sandy marine deposit of Pleistocene age

occurs at the surface in most of the area.

Climate

The average annual precipitation in this area is 44 to 60

inches (1,120 to 1,525 millimeters). About 60 percent of the

precipitation occurs from June through September. Most of the

rainfall occurs as moderate-intensity, tropical storms that

produce large amounts of rain from late spring through early

autumn. Late autumn and winter are relatively dry. The average

annual temperature is 68 to 75 degrees F (20 to 24 degrees C).

The freeze-free period averages 335 days and ranges from 300

to 365 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 3.7%; ground water, 15.1%

Livestock—surface water, 0.2%; ground water, 1.4%

Irrigation—surface water, 21.4%; ground water, 35.6%

Other—surface water, 14.2%; ground water, 8.4%

The total withdrawals average 3,500 million gallons per day

(13,250 million liters per day). About 60 percent is from ground

water sources, and 40 percent is from surface water sources.

Rainfall and surface and ground water sources provide an

abundance of water. Canals and ditches control the ground

water level for crops and pasture. Excess water is pumped out

during the rainy season, and irrigation water is applied during

the growing season. The surface water is of good quality.

Most of the domestic, municipal, and irrigation water in the

area is obtained from wells in the artesian Floridan aquifer,

which consists of deep limestone and dolomite beds. This

aquifer is one of the most productive ground water sources in

the United States. The water from this aquifer is a calcium

bicarbonate type. It is hard, and it has high amounts of total

dissolved solids in some areas.

A source of drinking water in this area is a nonartesian

aquifer of sand, shells, and limestone that occurs in a belt across

the southern and central parts of this MLRA. This shallow

aquifer provides limited quantities of good-quality water. The

water is a calcium bicarbonate type that is hard or very hard. It

is highly susceptible to contamination from surface activities.

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, and Spodosols. The soils in the area dominantly have

a hyperthermic soil temperature regime, an aquic soil moisture

regime, and siliceous mineralogy. They generally are deep or

very deep, poorly drained or very poorly drained, and loamy or

sandy. Endoaqualfs (Holopaw and Malabar series) and

Glossaqualfs (Pineda and Riviera series) formed in loamy

marine sediments on flats and flood plains and in depressions.

Alaquods (Eaugallie, Immokalee, Myakka, Oldsmar, Smyrna,

and Wabasso series) and Psammaquents (Basinger series)

formed in sandy marine deposits on flats and flood plains and

in depressions.

Biological Resources

This area supports “flatwood” forest vegetation. Slash pine,

longleaf pine, cabbage palm, and live oak are the principal

species. Saw palmetto, gallberry, and grasses, such as bluestems

and wiregrasses, characterize the understory.
522 Major Land Resource Areas

Figure 156A-1: Location of MLRA 156A in Land Resource Region U.

Some of the major wildlife species in this area are whitetailed deer, feral hog, bobcat, squirrel, snipe, raccoon, skunk,

otter, bobwhite quail, woodpecker, and mourning dove. The

species of fish in the area include black crappie, largemouth

bass, bluegill, and catfish.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 7%

Grassland—private, 36%

Forest—private, 19%; Federal, 3%

Urban development—private, 17%

Water—private, 13%

Other—private, 5%

The forestland in this area consists mainly of low-quality

pine. It is grazed extensively. More than one-third of the area is

improved pasture or native range grazed by cattle. The limited

acreage of cropland in the area is used mainly for many kinds of

winter vegetables. Some citrus fruits are grown in the area, and

other subtropical fruits are grown in the southern part of the

area.

The major soil resource concerns are wind erosion,

maintenance of the content of organic matter and

productivity of the soils, and management of soil moisture.

Conservation practices on cropland generally include

conservation crop rotations, cover crops, irrigation water

management (including microirrigation systems), nutrient

management, and pest management. Conservation practices on

pasture and rangeland generally include prescribed grazing,

brush management, pest management, prescribed burning, and

watering facilities. Conservation practices on forestland

generally include forest stand improvement, forest site

preparation, prescribed burning, firebreaks, establishment of

trees and shrubs, pest management, and management of upland

wildlife habitat. 

156A—Florida Everglades and

Associated Areas

This area is entirely in Florida (fig. 156A-1). It makes up

about 6,915 square miles (17,920 square kilometers). Miami

and other cities are on the Atlantic coast, the eastern edge of

the area. Interstate 75 bisects the northern half of the largest

part of this MLRA, and Interstate 95 parallels the Atlantic

coast. A small part of this MLRA is north of Florida’s Turnpike

and west of Interstate 95, in Brevard County. Everglades

National Park, Big Cypress National Preserve, the Big Cypress

Seminole Indian Reservation, and the southeast half of Lake

Okeechobee occur in this area.

Physiography

This area is in the Floridian Section of the Coastal Plain

Province of the Atlantic Plain. It is on a level, low coastal plain

that has large areas of swamps and marshes. Poorly defined and

broad streams, canals, and ditches drain the area to the ocean.

Most of the area is flat, but in the interior, hummocks rise 3 to 6

feet (1 to 2 meters) above the general level of the landscape and

low beach ridges and dunes, mainly in the eastern part of the

area, rise 10 to 15 feet (3 to 5 meters) above the adjoining

swamps and marshes. Elevation ranges from sea level to less

than 80 feet (25 meters).

The only major Hydrologic Unit Area (identified by a fourdigit number) that makes up this MLRA is Southern Florida

(0309). The area has no major rivers, but a number of canals

cross the northern half of the area.
of the United States 523

Geology

This area is a young marine plain underlain by Tertiary-age

rocks, including very fine grained shale, mudstone, limestone,

and dolomite beds. Limestone rock is the dominant subsurface

material in this MLRA. A sandy marine deposit of Pleistocene

age occurs at the surface in the northern part of the area and in

the part in Brevard County.

Climate

The average annual precipitation in this area is 40 to 62

inches (1,015 to 1,575 millimeters). About 60 percent of the

precipitation occurs from June through September. The center

of the area is the driest part. Most of the rainfall occurs as

moderate-intensity, tropical storms that produce large amounts

of rain from late spring through early autumn. Late autumn and

winter are relatively dry. The average annual temperature is 73

to 78 degrees F (23 to 25 degrees C). The freeze-free period

averages 355 days and ranges from 345 to 365 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 2.7%; ground water, 22.9%

Livestock—surface water, 0.1%; ground water, 0.3%

Irrigation—surface water, 38.9%; ground water, 10.8%

Other—surface water, 11.4%; ground water, 12.8%

The total withdrawals average 1,850 million gallons per day

(7,000 million liters per day). About 47 percent is from ground

water sources, and 53 percent is from surface water sources.

Rainfall and surface and ground water sources provide an

abundance of water. Unless the water level in naturally wet

areas is controlled, shallow water covers the surface during

much of the rainy season. Canals and ditches control the

ground water level for crops and pasture. Excess water is

pumped out during the rainy season, and irrigation water is

applied during the growing season. The surface water is

generally of good quality.

Domestic water is obtained mainly from wells in a shallow,

nonartesian aquifer of sand, shells, and limestone or from the

Biscayne aquifer in the eastern half of this MLRA. The shallow

aquifer provides limited quantities of good-quality water. The

Biscayne aquifer is a “sole source” drinking water supply for

much of Dade and Broward Counties and parts of Monroe and

Palm Beach Counties. The aquifer consists of very permeable

limestone that has good-quality water. Some high-capacity

irrigation wells tap the Biscayne aquifer. All of the ground

water is a calcium bicarbonate type and is hard or very hard.

Some saline water problems occur in the Biscayne aquifer near

the coast. These aquifers are susceptible to contamination from

surface activities.

The northern part of this MLRA has abundant surface and

ground water of good quality. The Floridan aquifer is the

primary source of ground water in Brevard County. This aquifer

consists of deep limestone and dolomite beds. The water in this

aquifer is a calcium bicarbonate type and is hard.

Soils

The dominant soil orders in this MLRA are Entisols and

Histosols. The soils in the area dominantly have a hyperthermic

soil temperature regime, an aquic or udic soil moisture regime,

and carbonatic mineralogy. They are very shallow to very deep,

generally moderately well drained to very poorly drained, and

loamy or sandy. Udorthents (Krome series) formed in residuum

on flats. Fluvaquents (Biscayne and Perrine series) and

Psammaquents (Hallandale series) formed in marine sediments

on flats and in depressions and sloughs. Haplosaprists (Pahokee

and Terra Ceia series) formed in organic deposits in marshes.

Biological Resources

This area supports freshwater marsh and swamp vegetation.

Sawgrass, pickleweed, willow, buttonbush, and maidencane are

the dominant marsh species. Bald cypress is the dominant

swamp species. Mangrove trees grow in saltwater swamps along

the eastern, southern, and southwestern coasts.

Some of the major wildlife species in this area are whitetailed deer, feral hog, snipe, bobcat, raccoon, skunk, otter,

squirrel, bobwhite quail, and woodpecker. Alligators, turtles,

and wading birds, including wood storks, white ibis, glossy

ibis, egrets, and herons, are abundant in the swamps and

marshes. The species of fish in the area include black drum, red

drum, sea trout, sheepshead, snook, tarpon, and largemouth

bass.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 11%

Grassland—private, 8%; Federal, 24%

Forest—private, 3%; Federal, 7%

Urban development—private, 12%

Water—private, 5%; Federal, 4%

Other—private, 26%

About one-third of this area is in Indian reservations,

national parks, game refuges, or other large holdings. Cypress

forests are extensive in the area, but mangrove forests are

widespread along the eastern and southern coasts. A large part

of the area is open marsh. Much of the area is used for hunting,

fishing, and other recreational activities. The cropland in the

area is used mainly for winter vegetables, but citrus fruits,

avocado, and papaya are grown on the better drained soils.

Sugarcane is an important crop on the organic soils south of
524 Major Land Resource Areas

Lake Okeechobee. The acreage of improved pasture is

increasing. Beef cattle are the principal kind of livestock, but

dairying is an important enterprise locally. Urbanization is

extensive along the eastern coast.

The major soil resource concerns are wind erosion,

maintenance of the content of organic matter and productivity

of the soils, and management of soil moisture and soil

subsidence. Conservation practices on cropland generally

include conservation crop rotations, cover crops, nutrient

management, pest management, water-control structures,

surface drainage systems (field ditches, mains, and laterals),

pumping plants, and irrigation water management (including

microirrigation systems and surface and subsurface irrigation

systems). Conservation practices on pasture and rangeland

generally include prescribed grazing, brush management, pest

management, prescribed burning, and watering facilities.

Conservation practices on forestland generally include forest

stand improvement, firebreaks, pest management, prescribed

burning, and management of upland and wetland wildlife

habitat. 

Figure 156B-1: Location of MLRA 156B in Land Resource Region U.

156B—Southern Florida Lowlands

This area is entirely in Florida (fig. 156B-1). It makes up

about 1,835 square miles (4,750 square kilometers). It has no

major cities or towns. It lies between Lake Okeechobee and the

eastern coast. Interstate 95 parallels the eastern boundary of the

area.

Physiography

This area is in the Floridian Section of the Coastal Plain

Province of the Atlantic Plain. It is on nearly level lowlands.

Agricultural canals drain this area. A few hummocks rise 3 to 6

feet (1 to 2 meters) above the general level of the landscape.

Elevation is approximately 80 feet (25 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Southern Florida (0309), 56 percent, and St. Johns (0308), 44

percent.

Geology

This area is a young marine plain underlain by Tertiary-age

rocks, including very fine grained shale, mudstone, limestone,

and dolomite beds. A sandy marine deposit of Pleistocene age

occurs at the surface in much of this area.

Climate

The average annual precipitation in this area is 46 to 60

inches (1,170 to 1,525 millimeters). About 60 percent of the

precipitation occurs from June through September. Most of the

rainfall occurs as moderate-intensity, tropical storms that

produce large amounts of rain during the summer. Spring, fall,

and winter are relatively dry. The average annual temperature is

71 to 74 degrees F (22 to 24 degrees C). The freeze-free period

averages 360 days and ranges from 360 to 365 days.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 0.2%; ground water, 5.6%

Livestock—surface water, 0.1%; ground water, 0.4%

Irrigation—surface water, 49.0%; ground water, 32.7%

Other—surface water, 2.8%; ground water, 9.3%

The total withdrawals average 305 million gallons per day

(1,155 million liters per day). About 48 percent is from ground

water sources, and 52 percent is from surface water sources.

Rainfall and surface and ground water sources provide an
of the United States 525

abundance of water. The surface water is of good quality. Unless

the water level in naturally wet areas is controlled, shallow

water covers the surface during much of the rainy season.

Canals and ditches control the ground water level for crops and

pasture. Excess water is pumped out during the rainy season,

and irrigation water is applied during the growing season.

Domestic water is obtained mainly from wells in a shallow,

nonartesian aquifer. This aquifer provides limited quantities of

water that is hard but of good quality. The water is dominantly

a calcium bicarbonate type. High-capacity irrigation wells are

usually drilled down to the artesian Floridan aquifer, which

consists of deep limestone and dolomite beds. The water in this

aquifer is a calcium bicarbonate type but has high amounts of

total dissolved solids in this area. In some areas the artesian

water is too salty for direct application on salt-sensitive citrus

crops. The shallow aquifer is susceptible to contamination from

surface activities.

Soils

The dominant soil orders in this MLRA are Alfisols,

Entisols, and Histosols. The soils in the area dominantly have a

hyperthermic soil temperature regime, an aquic soil moisture

regime, and siliceous mineralogy. They generally are deep or

very deep, poorly drained or very poorly drained, and loamy or

sandy. Glossaqualfs (Pineda, Riviera, and Winder series),

Endoaqualfs (Felda series), and Argiaquolls (Floridana series)

formed in loamy marine sediments on flats and flood plains and

in depressions. Psammaquents (Basinger series) formed in

sandy marine sediments on flats and in depressions.

Haplosaprists (Terra Ceia series) formed in organic deposits in

marshes.

Biological Resources

This area supports “hummock and slough” swamp

vegetation. Slash pine and cabbage palm are the dominant

species. Saw palmetto, cordgrasses, and bluestems make up the

understory.

Some of the major wildlife species in this area are whitetailed deer, feral hog, gray fox, raccoon, opossum, armadillo,

rabbit, tree squirrel, wild turkey, bobwhite quail, mourning

dove, Florida mallard, and woodpecker.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 24%

Grassland—private, 37%

Forest—private, 6%

Urban development—private, 15%

Water—private, 4%

Other—private, 14%

Most of this area is in farms or ranches. Citrus fruits, the

chief crops, are planted in beds between shallow ditches that

are part of the water-control system. The vegetation on the

rangeland in the area consists of native grasses, forbs, sedges,

and a few scattered pines. The forestland in the area consists

of mixed pine and cabbage palm or cabbage palm and

hardwoods.

The major soil resource concerns are wind erosion,

maintenance of the content of organic matter and productivity

of the soils, and management of soil moisture. Conservation

practices on cropland generally include conservation crop

rotations, cover crops, nutrient management, pest management,

water-control structures, surface drainage systems (field ditches,

mains, and laterals), pumping plants, and irrigation water

management (including microirrigation systems and surface and

subsurface irrigation systems). Conservation practices on

pasture and rangeland generally include prescribed grazing,

brush management, pest management, prescribed burning, and

watering facilities. 

527

Figure V-1: Location of Land Resource Region V.

V—Hawaii Region

This region is in the Hawaiian Islands (fig. V-1). It makes up

about 6,265 square miles (16,260 square kilometers).

This region consists of eight major islands (fig. V-2). These

islands are of volcanic origin and consist of coastal plains,

upland slopes, mountain ranges, plateaus, and summits. This is

a region of warm to hot temperatures. Precipitation extremes are

normal on each island. The windward (north and northeast) side

of the islands receives heavy annual rainfall, mostly occurring

from November to March or April. The leeward side receives

little rainfall. It is subject to “kona” storms, which come from

the leeward side of the islands and provide most of the annual

precipitation in many areas. Winters are pleasantly warm. The

average annual precipitation ranges from 60 to 220 inches

(1,525 to 5,590 millimeters) on the windward side of the islands

and from 30 to 60 inches (760 to 1,525 millimeters) on the

leeward side. The average annual temperature ranges from 56 to

75 degrees F (14 to 24 degrees C). The freeze-free period is

typically 365 days on all of the islands. Freezing temperatures

occur annually at the tops of the higher volcanic peaks.

The total withdrawals of freshwater in this region average

about 1,190 million gallons per day (4,505 million liters per

day). About 50 percent is from surface water sources, and 50

percent is from ground water sources. About 64 percent of the

water is used for irrigation, 20 percent is used for public supply,

and 16 percent is used for municipal and industrial supply.

The soils in this region are dominantly Andisols. Mollisols,

Aridisols, Histosols, Oxisols, and Inceptisols are of lesser

extent. The region has a significant area of volcanic rock,

which is classified as nonsoil. The dominant suborders are

Ustands, Udands, and Ustolls that formed in weathered volcanic

ash and basalt on uplands. Cambids also are common on

uplands. Folists are common on wet mountain slopes. The soils

in the region dominantly have an isohyperthermic or

isothermic soil temperature regime, an ustic or udic soil

moisture regime, and mixed mineralogy.

About 92 percent of the region is privately owned. The

native vegetation ranges from desert shrubs and grasses to

subtropical forest. Pineapples and coffee are the major export

crops. Macadamia, papaya, and floral products are other

important export crops. Truck crops, mainly tomatoes,
528 Major Land Resource Areas

Figure V-2: An area of Kauai, one of the tropical islands making up Land Resource Region V.

cucumbers, head cabbage, lettuce, green peppers, snap beans,

bananas, and such specialty crops as ginger and taro, also are

important. Cattle ranching is important to the local economy.

The forests in the region are used mainly for watershed, wildlife

habitat, and recreation. Because of the pleasant climate and the

tropical island scenery, tourism is an important industry. The

most significant resource concern is the invasion of foreign

plants and animals. Other concerns include water erosion and

nutrient and pesticide runoff and leaching. 
of the United States 529

Figure 157-1: Location of MLRA 157 in Land Resource Region V.

157—Arid and Semiarid Low Mountain

Slopes

This area is in the Hawaiian Islands (fig. 157-1). It makes up

about 265 square miles (690 square kilometers). The town of

Wailea and State Highway 31 are in the part of this area on

Maui. Waikaloa Village and the Hapuna Beach Recreation Area

are in the part on the Big Island of Hawaii. State Highways 19,

190, 200, and 270 cross the part on the Big Island.

Physiography

This area is on moderately dissected, gently sloping to steep,

leeward mountain slopes on the geologically younger islands

of Maui and Hawaii. Elevation ranges from near sea level to

6,000 feet (0 to 1,830 meters). Local relief ranges from 1,500 to

6,000 feet (455 to 1,830 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Hawaii (2001), 77 percent, and Maui (2002), 23 percent. The

area has no perennial streams.

Geology

This MLRA is underlain dominantly by aa (basalt), which is

covered by volcanic ash. The MLRA has minor areas of

weathered andesite and basalt. Olivine sand is mixed with the

ash deposits on the south- and east-facing slopes on the coastal

uplands.

Climate

The average annual precipitation in most of this area is 10 to

35 inches (255 to 890 millimeters). It can exceed 45 inches

(1,145 millimeters) on interior slopes at the higher elevations.

Most of the rainfall occurs from October through May. Much of

it occurs during kona storms, which occur in winter and usually

bring rain for several hours to several days. They are called

kona storms because they bring wind from the “kona” or

leeward direction on the islands. The average annual

temperature is 55 to 76 degrees F (13 to 24 degrees C). The

average freeze-free period is 365 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.9%; ground water, 0.0%

Livestock—surface water, 0.9%; ground water, 0.9%

Irrigation—surface water, 68.6%; ground water, 27.5%

Other—surface water, 1.1%; ground water, 0.0%

The total withdrawals average 44 million gallons per day

(165 million liters per day). About 28 percent is from ground

water sources, and 72 percent is from surface water sources. The

amount of rainfall is not adequate for crop production without

irrigation. Because of the lack of perennial streams in this

MLRA, water for public supply and almost all irrigation and

livestock use is imported into this area from adjacent MLRAs

with more plentiful water resources.

All three of the volcanic rock aquifers on the island of

Hawaii and the two on Maui occur in this area. The ground

water away from the Hawaiian coast is of good quality and is

suitable for almost all uses. Near the coast, however, the water is

of lower quality because of increased levels of salts from the

intrusion of seawater. Some rural landowners still utilize these

aquifers for domestic and livestock water, but the level of total

dissolved solids typically exceeds 1,000 parts per million

(milligrams per liter), so most of the ground water near the coast

is used for irrigation.

Soils

The dominant soil orders in this MLRA are Andisols,

Mollisols, and Aridisols. The soils in the area have an

isohyperthermic or isothermic soil temperature regime, an ustic

or aridic soil moisture regime, and dominantly amorphic

mineralogy. They generally are moderately deep to very deep,

well drained, and loamy. The soils are nonstony to extremely

stony. Haplustands include the Kikoni, Kula, Pane, Puu Pa, and

Waimea series; Haplotorrands include the Makena and Pakini

series; and Vitritorrands include the Oanapuka series.

Haplustolls (Kamaole series) formed in volcanic ash underlain

by aa. Haplocambids (Kawaihae series) formed in volcanic ash

on leeward coastal uplands. The MLRA has a significant

acreage of miscellaneous (nonsoil) areas.
530 Major Land Resource Areas

Figure 158-1: Location of MLRA 158 in Land Resource Region V.

Biological Resources

This area is dominated by grass-shrub vegetation. The

naturalized vegetation at the lower elevations includes kiawe,

bermudagrass, lantana, fingergrass, and cactus. The native

vegetation at the lower elevations includes ilima, piligrass, and

uhaloa. At the higher elevations, naturalized kikuyugrass, white

clover, and rattailgrass are common and the native species

include the aiea tree, and on Maui, two rare species—ko ́oloa

 ́ula (Chinese lantern) and pua aloalo (delicate yellow

hibiscus). Yellow hibiscus is Hawaii’s State flower.

The major wildlife species in the area include introduced

game birds, such as pheasant, chukar, dove, and francolin. The

upper elevations on Maui are designated as critical habitat for

the Blackburn’s sphinx moth.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—private, 85%

Forest—private, 3%

Urban development—private, 2%

Other—private, 10%

Most of this area is rangeland that is grazed primarily during

the winter rainy season. Forage production is low during the

dry summer months, so cattle are usually moved to wetter areas

during that part of the year. Irrigated truck crops are grown in

small areas at an elevation near 2,000 feet (610 meters). The

local climate and soils are suitable for cool-season crops, such

as head cabbage, head lettuce, celery, and round onions.

Tomatoes are grown throughout the year. Some coastal areas are

used for urban or resort development.

The major soil resource concerns are water erosion and wind

erosion. Conservation practices on rangeland generally include

prescribed grazing and brush management. Conservation

practices on cropland generally include sprinkler irrigation and

microirrigation, windbreaks, crop rotations, contour farming,

and nutrient and pest management. 

158—Semiarid and Subhumid Low

Mountain Slopes

This area is in the Hawaiian Islands (fig. 158-1). It makes up

about 520 square miles (1,340 square kilometers). It includes

the towns of Kapaa, Hanamaula, and Lihue, Kauai; Waialua and

Wahiawa, Oahu; Maunaloa, Molokai; Lanai City, Lanai;

Honokahua, Paia, and Kahalui, Maui; and Hawi and Halaula,

Hawaii. Interstate H2 terminates in the town of Wahiawa, Oahu,

and numerous State highways cross the area. The Schofield

Barracks Military Reservation and Wheeler Air Force Base are

in the part of this MLRA on Oahu.

Physiography

This area primarily lies on the leeward, drier side of the older

islands in the Hawaiian Islands chain. It is on nearly level to

moderately steep slopes on plains that are dissected in places

by gulches. Elevation ranges from near sea level to 1,600 feet

(0 to 490 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Kauai (2007), 30 percent; Maui (2002), 24 percent; Oahu

(2006), 18 percent; Molokai (2005), 15 percent; Hawaii (2001),

7 percent; and Lanai (2004), 6 percent. This area has no major

rivers but has a number of perennial streams.

Geology

Most of the surface of this area is covered with highly

weathered volcanic ash, which overlies basic igneous rocks.

Alluvium derived from basic igneous rocks occurs in some

moderately extensive areas of intermediate uplands.

Climate

The average annual precipitation in much of this area is 10

to 30 inches (255 to 760 millimeters). It can exceed 60 inches

(1,525 millimeters) on the east and northeast sides of Kauai, in

central Oahu, and on the north side of Hawaii. Most of the

rainfall occurs from November through March. Much of it

occurs during kona storms. The average annual temperature is

69 to 76 degrees F (21 to 24 degrees C). The freeze-free period

averages 365 days.
of the United States 531

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.8%; ground water, 2.9%

Livestock—surface water, 0.1%; ground water, 0.1%

Irrigation—surface water, 65.1%; ground water, 23.0%

Other—surface water, 1.6%; ground water, 6.3%

The total withdrawals average 670 million gallons per day

(2,535 million liters per day). About 32 percent is from ground

water sources, and 68 percent is from surface water sources.

Irrigation is required for the growth of crops in most of this area.

Some parts of the MLRA are in high-rainfall (windward) zones

on the islands where surface water is plentiful and irrigation is

not necessary. Some surface water is trapped in these zones and

piped to drier areas, where it is used for irrigation. A number of

perennial streams occur in this area. The surface water in the

area is used primarily for irrigation and for watering livestock.

An exception is Maui, where almost all of the domestic water

supply is surface water. The water has good chemical quality,

but it typically requires treatment for physical and biological

quality before it can be used as drinking water.

Little surface water is available in the part of this area on

Molokai. In the 1960s, when pineapple production was at its

height, a tunnel was constructed to bring water from the

windward side of the island to the center of the island. The

tunnel is still serviceable, but it is not being used at full

capacity today.

Ground water of suitable quality for almost all uses can be

obtained from three aquifers on Kauai—the Napali volcanic

aquifer, the Koloa and Olokele volcanic aquifer, and the

alluvial sediments in the river valleys. The median level of

total dissolved solids is less than 500 parts per million

(milligrams per liter) in the water in each of these aquifers, but

the water in the volcanic aquifers is very hard and requires

some treatment prior to use for domestic and public supplies.

Good-quality ground water for most uses also can be

obtained from three aquifers on Oahu—the Koolau volcanic

aquifer, the Waianae and Honolulu volcanic aquifer, and

alluvial sediments. The median level of total dissolved solids is

less than 200 parts per million (milligrams per liter) in the water

in these aquifers, and the water in the volcanic aquifers is soft,

so little treatment is required before the water is used as

drinking water.

There are no available data on the quality of the water in the

East Molokai volcanic rocks aquifer. Poor-quality ground water

can be obtained from three aquifers on Maui—the Honolua

volcanic aquifer, the Kula volcanic aquifer, and the sedimentary

material in the isthmus area. The median level of total

dissolved solids is close to 1,000 parts per million (milligrams

per liter) in the water in each of these aquifers, and the water in

the volcanic aquifers is very hard. Because of water-quality

problems, ground water on Kauai and Maui is used primarily

for irrigation.

The Kau volcanic rock aquifer on the Big Island has water

with the lowest levels of total dissolved solids and the softest

water of all the aquifers on all the islands, especially near the

center of the island, where recharge occurs. The level of salts in

the water may be higher than the median for this aquifer since

this MLRA is located on the northwest coast of Hawaii.

Pumping tends to increase the level of seawater intrusion into

the “basal water.” Most of the ground water in this area floats as

a lens of freshwater on the denser saltwater that occurs at depth

in each aquifer. When freshwater is pumped out of the aquifer,

the seawater tends to move higher into the aquifer,

contaminating the freshwater. Seawater intrusion is most

common near the coast, so the ground water may be limited for

use as drinking water in this area.

The silica level in the water from all of the volcanic rock

aquifers in the area exceeds 30 parts per million (milligrams per

liter). The level of silica limits the industrial use of the ground

water. At this concentration, silica combines with calcium and

magnesium to form a scale that can create problems, especially

in boilers and steam turbines.

Soils

The dominant soil orders in this MLRA are Oxisols,

Mollisols, and Aridisols. The soils in the area have an

isohyperthermic soil temperature regime, an ustic or aridic

(torric) soil moisture regime, and dominantly kaolinitic

mineralogy. They generally are very deep, well drained, and

very fine textured. Haplocambids (Keahua series) formed in

material weathered from basic igneous rocks. Eutrustox

(Lahaina and Lihue series), Haplustolls (Makaweli and Paia

series), and Eutrotorrox (Molokai series) formed in residuum on

uplands from sea level to 1,500 feet (0 to 455 meters).

Kandiustox (Puhi series) are in upland areas influenced by the

higher amounts of average annual rainfall. Haplustox (Wahiawa

series) formed in alluvium derived from basalt and ash on

uplands with long slopes that have not been eroded. The

MLRA has a significant acreage of miscellaneous (nonsoil)

areas.

Biological Resources

The naturalized scrub-shrub and grassland species in this

area include koa haole, bermudagrass, and guineagrass. The

native species include ilima, piligrass, and uhaloa. Ohai, a rare

shrub, grows along the coast of Molokai.

Some of the major wildlife species in this MLRA include

nonnative game birds, such as francolins and doves. On Maui,

Oahu, and Kauai, the endangered Hawaiian bat is known to

occur. The endangered species in areas of reservoirs and

wetlands include stilts and nene on Maui; stilts, nene, koloa
532 Major Land Resource Areas

Figure 159A-1: Location of MLRA 159A in Land Resource Region V.

duck, coots, and moorhen on Kauai; and stilts, coots, and

moorhen on Oahu. The nene, a land bird and variety of

Hawaiian goose, is the State bird of Hawaii. On Kauai, critical

habitat has been designated for the endangered cave wolf

spider and cave amphipod.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 23%

Grassland—private, 56%; Federal, 1%

Forest—private, 9%

Urban development—private, 7%; Federal, 1%

Water—private, 1%

Other—private, 2%

Farms and ranches make up nearly all of this area. Cultivated

areas are used for irrigated sugarcane, pineapples, truck crops,

or orchards. Also, some small areas are used for pasture. Some

areas are used for urban development or military installations.

The major soil resource concerns include water erosion,

wind erosion, and nutrient and pesticide runoff and leaching.

The availability of irrigation water also is a concern.

Conservation practices on cropland and grassland generally

include nutrient and pest management, crop rotations, crop

residue management, windbreaks, and cover crops. 

159A—Humid and Very Humid Volcanic

Ash Soils on Low and Intermediate

Rolling Mountain Slopes

This area is in the Hawaiian Islands (fig. 159A-1). It makes

up about 535 square miles (1,390 square kilometers). The towns

of Honokaa, Hilo, Keaau, and Mountain View, Hawaii, and

Hana, Maui, are in this MLRA. State Highways 11 and 19 cross

the part of this area on the Big Island, and State Highway 360

(Hana Highway) crosses the part on Maui. The Hawaii

Volcanoes National Park is on the western border of the part on

the Big Island.

Physiography

This area lies on the windward, wetter side of the Islands of

Hawaii and Maui. The area is on rolling mountain slopes that

have been eroded by steep-sided gulches. Elevation ranges

from near sea level to 6,000 feet (0 to 1,830 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Hawaii (2001), 91 percent, and Maui (2002), 9 percent. The

area has no major rivers, but a few perennial streams drain the

area.

Geology

In most of this area, volcanic ash is underlain by basic

igneous rocks. Some areas have volcanic ash over cinders.

Climate

The average annual precipitation in most of this area is 120

to 200 inches (3,050 to 5,080 millimeters). It can be as high as

300 inches (7,620 millimeters) in rain-forest zones and can be

as low as 70 inches (1,780 millimeters) in the extreme north and

west inland parts of the area. The average annual temperature is

54 to 73 degrees F (12 to 23 degrees C). The freeze-free period

averages 365 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 5.3%; ground water, 26.4%

Livestock—surface water, 1.7%; ground water, 3.3%

Irrigation—surface water, 45.2%; ground water, 14.5%

Other—surface water, 3.6%; ground water, 0.0%

The total withdrawals average 30 million gallons per day

(115 million liters per day). About 44 percent is from ground

water sources, and 56 percent is from surface water sources.

Almost all of this MLRA is in high-rainfall (windward) areas on

the islands, so surface water typically is plentiful and irrigation

is not needed. The western part of the Hamakua coast requires

supplemental irrigation during the drier season. The area has a

few perennial streams but no storage reservoirs or lakes. The

surface water is used primarily for irrigation and for watering

livestock. An exception is Maui, where almost all of the
of the United States 533

domestic water supply is surface water. The water has good

chemical quality, but it typically requires treatment for

physical and biological quality before it can be used as

drinking water.

Poor-quality ground water is obtained primarily from the

Honolua and Hana volcanic aquifer in the part of this area on

Maui. The median level of total dissolved solids is close to

1,000 parts per million (milligrams per liter), and the water is

very hard. Since this MLRA is on the coast of Maui, seawater

intrusion can be a problem in the volcanic rock aquifer.

Because of water-quality problems, the ground water on Maui

is used primarily for irrigation.

All three volcanic rock aquifers on the island of Hawaii

occur in this area. They include the Kau aquifer; the Puna,

Hualalai, Kahuku, and Hamakua aquifer; and the Laupahoehoe

and Hawi aquifer. Tests indicate that the ground water in the

Kau aquifer has a median level of about 100 parts per million

(milligrams per liter) total dissolved solids and is soft. The

water is suitable for almost all uses with little or no treatment.

The silica level in the water from all of the volcanic rock

aquifers exceeds 30 parts per million (milligrams per liter). The

level of silica limits the industrial use of the ground water. At

this concentration, silica combines with calcium and

magnesium to form a scale that can create problems, especially

in boilers and steam turbines.

Soils

The dominant soils in this MLRA are Andisols. The soils in

the area have an isothermic or isohyperthermic soil temperature

regime, a udic or perudic soil moisture regime, and dominantly

ferrihydritic mineralogy. They generally are very deep, well

drained or moderately well drained, and hydrous. Hydrudands

(Akaka, Hana, Honokaa, Kailua, and Kaiwiki series) formed in

volcanic ash. Medial soil forms the upper part of some

Hydrudands (Hilo series).

Biological Resources

This area supports forest vegetation and naturalized pasture

grasses. The naturalized vegetation includes hilograss,

California grass, kikuyugrass, and rattailgrass. It also includes

eucalyptus and guava. Native forest and remnant patches

include ohia leua, koa, treefern, and uluhe. Stenogyne

scrophulariodes (no common name), a plant species of concern,

occurs on the Big Island.

Some of the major wildlife species in the area include

invasive feral pigs and mongooses and exotic birds, such as

pheasants, chukars, meadowlarks, turkeys, and francolins. The

native species on the Big Island include the endangered

Hawaiian hawk and the endangered Hawaiian bat. On Maui, the

upper elevations around Hana include critical habitat for

numerous plant species, including `Oha wai.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 2%

Grassland—private, 37%; Federal, 1%

Forest—private, 48%; Federal, 11%

Urban development—private, 1%

Rangeland and woodland make up most of this area. Some

areas are used intensively for orchards, eucalyptus plantations,

or cropland. Some small areas are used for ornamentals. Forest

reserves are maintained for the protection of rare, threatened, or

endangered native plants.

The major resource concerns are water erosion, nutrient and

pesticide leaching and runoff, surface compaction, plant

disease, and excess moisture. Conservation practices on

cropland and rangeland generally include erosion control,

nutrient and pest management, and deep tillage. 

159B—Subhumid and Humid Low and

Intermediate Mountain Slopes

This MLRA is in the Kau area on the Big Island of Hawaii

(fig. 159B-1). It makes up about 245 square miles (640 square

kilometers). The towns of Naalehu and Pahala are in this

MLRA. The total population in the area is low. State Highway

11 crosses the area from north to south. Part of the Hawaii

Volcanoes National Park is in the southwestern portion of this

area.

Physiography

This area is on low and intermediate slopes of Mauna Loa on

the Big Island. It is on moderately dissected, gently sloping to

rolling slopes on the side of a large shield volcano. Elevation

ranges from near sea level to 6,000 feet (0 to 1,830 meters).

Local relief ranges from 3,000 to 6,000 feet (915 to 1,830

meters).

The only Hydrologic Unit Area (identified by a four-digit

number) that makes up this MLRA is Hawaii (2001). Few

perennial streams are on the geologically young surface of this

area.

Geology

Basic igneous rocks (basalt) underlie a mantle of basic

weathered volcanic ash in this area. Some alluvial fans occur,

and colluvium, typically a mixture of volcanic ash and cinders,

occurs in places.
534 Major Land Resource Areas

Figure 159B-1: Location of MLRA 159B in Land Resource Region V.

Climate

The average annual precipitation in this area is 50 to 100

inches (1,270 to 2,540 millimeters). Most of the rainfall occurs

from November through March. The average annual

temperature is 54 to 73 degrees F (12 to 23 degrees C). The

freeze-free period averages 365 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0%; ground water, 0%

Livestock—surface water, 20%; ground water, 40%

Irrigation—surface water, 20%; ground water, 20%

Other—surface water, 0%; ground water, 0%

The total withdrawals average 0.5 million gallons per day

(1.9 million liters per day). About 60 percent is from ground

water sources, and 40 percent is from surface water sources. The

amount of rainfall is generally adequate for crop production

without full irrigation, but some small areas of cropland on the

less steep slopes are irrigated. The area has few perennial

streams. Springs are in the volcanic rocks. The surface water is

typically suitable for irrigation and livestock but not as

drinking water.

The Kau volcanic rock aquifer and the Laupahoehoe and

Hawi volcanic rock aquifer occur in this area. The Kau volcanic

rock aquifer on the Big Island has the lowest levels of total

dissolved solids and the softest water of all the aquifers on all

the islands, especially near the center of the island, where

recharge occurs. The ground water from these aquifers is

suitable for almost all uses in this area. The silica level in the

ground water exceeds 30 parts per million (milligrams per liter).

The level of silica limits the industrial use of the ground water.

At this concentration, silica combines with calcium and

magnesium to form a scale that can create problems, especially

in boilers and steam turbines.

Soils

The soils in this MLRA are mainly Andisols or Histosols.

They have an isothermic soil temperature regime, a udic soil

moisture regime, and euic mineralogy. They are very deep to

very shallow, well drained or moderately well drained, hydrous

soils. Hydrudands (Akaka, Honokaa, and Kaiwiki series) formed

in material weathered from volcanic ash. Keei and Kekake soils

formed in volcanic ash over pahoehoe lava.

Biological Resources

The vegetation in this area consists of rain forest at the upper

elevations and mixed trees, shrubs, and grasses at the lower

elevations. The naturalized vegetation in the wetter areas

includes hilograss, California grass, and guava. The naturalized

vegetation in the drier areas includes Christmasberry,

guineagrass, bermudagrass, and Natal redtop. Native forest and

remnant patches include ohia leua, koa, and treefern. Two areas

are designated as critical habitat for plant clusters, one 531

acres (215 hectares) and the other 1,351 acres (545 hectares).

Kauila or kauwila is one of the keystone endangered plants in

these protected areas.

Some of the major wildlife species in the area are feral pigs,

mongoose, wild sheep, and exotic game birds. The native

wildlife in the area includes the endangered Hawaiian hawk,

the endangered Hawaiian bat, and the endangered akepa.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 3%

Grassland—private, 32%

Forest—private, 65%

Much of the land at the higher elevations in this area is in a

forest reserve that provides watershed and habitat and

protection for rare, threatened, and endangered plant species.

Most of the land at the lower elevations is rangeland. Some

small areas are used intensively for orchards, woodland, or

irrigated cropland. A large part of this area was used for

nonirrigated sugarcane for about 100 years, until the recent

closing of the sugar plantation. Some of the areas once used for

sugarcane are now used for cattle ranching, the production of

macadamia nuts, trees for biomass, or small truck farms.

The major resource concerns are water erosion, nutrient and

pesticide runoff and leaching, surface compaction, and plant

disease. Conservation practices on cropland and rangeland

generally include erosion and flood control and deep tillage. 
of the United States 535

160—Subhumid and Humid

Intermediate and High Mountain Slopes

This area is in the Hawaiian Islands (fig. 160-1). It makes up

about 500 square miles (1,290 square kilometers). The towns of

Waimea, Man, and Keanakolu on the Big Island and

Ulupalakua, Keokea, and Waiakoa on Maui are in this MLRA.

Much of the Kula area of Maui also is in this MLRA.

Physiography

This area is on hilly, intermediate to high slopes of the

Mauna Kea, Kohala, and Haleakala Mountains. The

topography is gently sloping to hilly, and cinder cones are

common. Elevation ranges from 1,000 to 9,000 feet (305 to

2,745 meters). Local relief ranges from 1,000 to 6,000 feet (305

to 1,830 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Hawaii (2001), 85 percent, and Maui (2002), 15 percent. This

MLRA is a headwaters area for local streams.

Geology

Most of this area consists of material weathered from

volcanic ash of different ages. At the higher elevations, some

areas have common outcrops of aa. Some small areas are

underlain by andesite or basalt bedrock. Alluvium in the area

consists of volcanic sand and gravel.

Climate

The average annual precipitation in this area is 20 to 75

inches (510 to 1,905 millimeters). Most of the rainfall occurs

during kona storms from November through March. Some

supplemental moisture is derived directly from the clouds that

typically occur above 2,000 feet (610 meters). The average

annual temperature is 50 to 71 degrees F (10 to 22 degrees C).

The freeze-free period averages 365 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 0.0%

Livestock—surface water, 16.7%; ground water, 16.7%

Irrigation—surface water, 50.0%; ground water, 16.7%

Other—surface water, 0.0%; ground water, 0.0%

The total withdrawals average about 0.6 million gallons per

day (about 2.3 million liters per day). About 33 percent is from

ground water sources, and 67 percent is from surface water

sources. Some irrigation water is applied in most of the areas

used for crops in the MLRA. Much of this water comes from

rain catchments with storage tanks, from lined reservoirs, or

from sources outside the MLRA. Most domestic and livestock

water is from catchments that empty into storage tanks. The

headwaters of a few perennial streams are in this area. The

surface water is suitable for most uses. Treatment is required

before the surface water that is not from catchments can be used

as drinking water.

This area is near drainage divides on Maui and Hawaii. Any

ground water at the higher elevations is probably trapped in the

subsurface behind or between intrusive dikes. The quantities of

water available depend on the geologic structure of a particular

area. Poor-quality ground water is obtained from the Honolua

and Kula volcanic aquifers in the part of this area on Maui. The

median level of total dissolved solids is close to 1,000 parts per

million (milligrams per liter) in other areas where this aquifer

occurs, and the water is very hard. Because of water-quality

problems, the ground water on Maui is used primarily for

irrigation.

The Puna, Hualalai, Kahuku, and Hamakua volcanic rock

aquifers and the Laupahoehoe and Hawi volcanic rock aquifer

occur in the part of this area on the Big Island. The water in

these aquifers typically has low levels of total dissolved solids

and is soft. It is suitable for almost all uses with little or no

treatment. The silica level in the water from all of the volcanic

rock aquifers exceeds 30 parts per million (milligrams per liter).

The level of silica limits the industrial use of the ground water.

At this concentration, silica combines with calcium and

magnesium to form a scale that can create problems, especially

in boilers and steam turbines.

Soils

The dominant soil order in this MLRA is Andisols. The soils

in the area have an isomesic soil temperature regime, an ustic or

udic soil moisture regime, and dominantly amorphic or

Figure 160-1: Location of MLRA 160 in Land Resource Region V.
536 Major Land Resource Areas

Figure 161A-1: Location of MLRA 161A in Land Resource Region V.

ferrihydritic mineralogy. They generally are deep, well drained,

and medial in texture. Haplustands (Hanipoe, Kaipoioi,

Laumaia, and Olinda series) and Hydrudands (Maile and Puu

Oo series) formed in material weathered from volcanic ash. The

MLRA has a significant acreage of miscellaneous (nonsoil)

areas.

Biological Resources

The vegetation in this area consists of temperate grasses,

shrubs, and trees. The naturalized vegetation, particularly in the

pastured areas, includes bermudagrass, eucalyptus, gorse,

kikuyugrass, Natal redtop, and rattailgrass. The native species

include koa ohia, naio, mamani, pukiawe, a ́ali ́i, and treefern.

Some of the major naturalized wildlife species in the area are

chickens, mongoose, numerous species of game birds, and feral

pigs, goats, axis deer (only on Maui), and mouflon sheep (only

on the Big Island). Part of the MLRA on the Big Island is

designated critical habitat for some rare, threatened, or

endangered plants and animals, including the endangered

Hawaiian palila, akiapolaau, and Hawaiian hawk. On Maui, the

upper elevations include an area designated as critical habitat

for the Blackburn’s sphinx moth.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—private, 75%; Federal, 3%

Forest—private, 14%; Federal, 2%

Urban development—private, 1%

Other—private, 3%; Federal, 2%

Most of this area is rangeland. Some small areas at

elevations of 2,000 to 3,000 feet (610 to 915 meters) are used

intensively for irrigated truck crops. The local climate and soils

at that elevation are suitable for cool-season crops, such as head

cabbage, head lettuce, celery, and round onions.

The major soil resource concern is water erosion.

Conservation practices on rangeland generally include proper

grazing use and brush management. Conservation practices on

cropland generally include irrigation water management,

windbreaks, crop rotations, contour farming, nutrient

management, and pest management. 

161A—Lava Flows and Rock Outcrops

This area is in the Hawaiian Islands (fig. 161A-1). It makes

up about 1,580 square miles (4,100 square kilometers). This

mountainous area has few towns and roads. It includes the

Hawaii Volcanoes National Park; the Mauna Kea Observatory

Complex; the Hualalai, Kilauea, and Mauna Loa volcanic

craters; and the Haleakala National Park, near the Red Hill

volcanic crater on Maui. The Pohakuloa Training Area, which

is the largest military reservation in Hawaii, also occurs in this

MLRA. It is between the Mauna Loa, Mauna Kea, and Hualalai

Mountains.

Physiography

This area extends from sea level to the tops of the Mauna

Kea, Mauna Loa, Haleakala, Kilauea, and Hualalai Mountains.

It is on undulating to hilly, barren lava flows, rocky cliffs, rock

outcrops, and steep cinder cones. Elevation ranges from sea

level to 13,796 feet (0 to 4,206 meters). Mauna Kea is the

highest point in Hawaii. Local relief ranges from 3,000 to

13,000 feet (915 to 3,965 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Hawaii (2001), 98 percent, and Maui (2002), 2 percent.

Geology

This area has young aa and pahoehoe lava that flowed from

the top or flanks of volcanoes. The surface of the aa lava is

fragmental, jagged, and rough. The surface of the pahoehoe is

smooth but has many cracks. Cinder cones are near the summits

of the volcanoes.

Climate

The average annual precipitation in this area is 10 to 100

inches (255 to 2,540 millimeters), generally increasing with

elevation. Most of the rainfall occurs from October through

March in most areas and from May through September in the

Kona area. The average annual temperature is 38 to 76 degrees

F (3 to 25 degrees C). The freeze-free period averages 365 days

in most of the area but is shorter at the highest elevations.
of the United States 537

Water

The withdrawals of freshwater by use are not estimated for

this MLRA. The total withdrawals average much less than 1

million gallons per day (less than 3.8 million liters per day).

The water used in this area is almost entirely surface water. The

low rainfall limits agricultural production in the area. Much of

the area is close to the craters of the large volcanoes on Maui

and Hawaii, so the area has few streams. Water for almost all

domestic uses and livestock is catchment water stored in tanks.

Some resorts and urban areas along the coast of Hawaii rely on

imported water from adjacent MLRAs. Very little or no ground

water is available for development in this area.

Soils

The dominant soil orders in this MLRA are Andisols and

Histosols. The soils in the area have an isohyperthermic to

isofrigid soil temperature regime and an ustic or udic soil

moisture regime. Most of the soils are organic. Mineral soils

have medial texture. Shallow Ustifolists (Kekake and Punalu`u

series) and shallow Udifolists (Keei, Kahaluu, and Kona series)

formed in organic material over pahoehoe lava. Shallow soils in

areas of volcanic ash include Haplustands (Kamawai and

Pu`ukala series). Fulvudands (Hokukano series) and

Ustivitrands (Nenenui series) formed in basic volcanic ash over

pahoehoe lava. Deep Haplustands (Apakuie series) and

Ustivitrands (Huikau and Kilohana series) formed on high

mountain slopes. The MLRA dominantly consists of

miscellaneous (nonsoil) areas, including lava flows, rock

outcrop, and cinder land.

Biological Resources

The vegetation in this area includes naturalized dryland

shrubs and grasses as well as rare dryland tree and shrub

communities. The vegetation varies considerably, depending

on the age of lava flow, rainfall, and elevation. Most areas,

including recent lava flows and the tops of volcanoes, have no

vegetation or have a sparse growth consisting of mosses,

lichens, and ferns. The dry areas at low elevations support

naturalized plants, such as kiawe, klu, and fountaingrass. The

naturalized plants in wet areas include guava and

molassesgrass.

The native vegetation in the area includes piligrass, ilima,

uhaloa, ohia, and pukiawe. The vegetation in much of the area

on the Big Island is classified as Sophora chrysophylla (no

common name)-bastard sandalwood subalpine dry forest and

lovegrass (Eragrostis atropioides) subalpine dry alpine

vegetation. Two critical habitat areas for multiple plant species

have been designated in this MLRA. One is about 70,000 acres

(28,330 hectares), and the other is about 95,000 acres (38,445

hectares). The protected species include ka`u silversword in the

first area and ohai and po ́e in the larger area.

Some of the major wildlife species in the area are feral

mouflon sheep (on the Big Island) and axis deer (on Maui). The

native wildlife includes nene (the State bird of Hawaii) on both

islands; the endangered Hawaiian palila, endangered Hawaiian

hawk, and endangered Hawaiian bat on the Big Island; and the

endangered pueo on Maui. In the area of Pu ́u wa ́a wa ́a on the

Big Island, critical habitat has been designated for the

endangered Blackburn’s sphinx moth.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—private, 28%; Federal, 6%

Forest—private, 10%

Other—private, 44%; Federal, 12%

The “other” category is dominantly barren lava flows and

cinder cones. The current land uses in this area are dominantly

recreation, wildlife habitat, rangeland, and some orchard

production. Low-producing grazing land is in the medium

rainfall belt. Some coastal areas are used for urban or resort

development.

The major resource concerns are wildfire, wind erosion,

drought, and flooding. Conservation practices on cropland and

rangeland generally include prescribed grazing, firebreaks, and

irrigation water management. 

161B—Semiarid and Subhumid Organic

Soils on Lava Flows

This MLRA is in the Kona coastal area on the leeward side

of the Big Island of Hawaii (fig. 161B-1). It makes up about 385

square miles (1,000 square kilometers). The towns of Papua,

Captain Cook, and Kealakekua are in this MLRA. Highway 11

is in the southern part of this area, and Highway 19 is in the far

northern part.

Physiography

This area is on the western slopes of the Mauna Loa and

Hualalai volcanoes. Slopes are undulating to very steep and

follow the rugged topography of the lava flows. Elevation

ranges from sea level to 6,000 feet (0 to 1,830 meters). Local

relief ranges from 50 to 1,000 feet (15 to 305 meters).

The only Hydrologic Unit Area (identified by a four-digit

number) that makes up this MLRA is Hawaii (2001). The

MLRA has no perennial streams.

Geology

The surface of this area is dominated by organic material

mixed with volcanic ash over aa and pahoehoe lava bedrock.
538 Major Land Resource Areas

Figure 161B-1: Location of MLRA 161B in Land Resource Region V.

Climate

The average annual precipitation in this area is 30 to 80

inches (760 to 2,030 millimeters). Most of the rainfall occurs in

spring and summer. The average annual temperature is 55 to 75

degrees F (13 to 24 degrees C). The freeze-free period averages

365 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 5.6%; ground water, 27.8%

Livestock—surface water, 11.1%; ground water, 0.0%

Irrigation—surface water, 27.8%; ground water, 27.8%

Other—surface water, 0.0%; ground water, 0.0%

The total withdrawals average 1.8 million gallons per day

(6.8 million liters per day). About 56 percent is from ground

water sources, and 44 percent is from surface water sources. This

MLRA is a low-rainfall area with no perennial streams. Much of

the irrigation water used in the area is imported from adjacent

MLRAs. Catchments are used at the higher elevations to trap

surface water, which is then piped to lower elevations for

livestock use. Much of the public and domestic drinking water

supply is distributed through pipelines from a few deep wells.

The Kau volcanic rock aquifer on the Big Island has the

lowest levels of total dissolved solids and the softest water of

all the aquifers on the islands, especially near the center of the

island, where recharge occurs. The level of salts in the water

may be higher than the median for this aquifer since much of

this MLRA is near the southwestern coast of Hawaii. Pumping

tends to increase the level of seawater intrusion into the “basal

water.” Most of the ground water in this area floats as a lens of

freshwater on the denser saltwater that occurs at depth in the

volcanic rock aquifer. When freshwater is pumped out of the

aquifer, the movement of seawater higher into the aquifer can

cause contamination. The intrusion of seawater is most

common near the coast, so the ground water can be limited for

use as drinking water in parts of this area. Away from the coast,

the ground water is suitable for almost all uses with little

treatment.

The silica levels in the water from the volcanic rock aquifer

exceeds 30 parts per million (milligrams per liter). The level of

silica limits the industrial use of the ground water. At this

concentration, silica combines with calcium and magnesium to

form a scale that can create problems, especially in boilers and

steam turbines.

Soils

The dominant soil orders in this MLRA are Histosols and

Andisols. The soils in the area have an isohyperthermic to

isomesic soil temperature regime, have an ustic or udic soil

moisture regime, and generally are organic. They are

dominantly very shallow to moderately deep and are well

drained. Most of the soils are Folists that are well drained,

organic soils in areas of aa or pahoehoe lava. Shallow

Ustifolists (Kekake and Punalu`u series) and very shallow

Udifolists (Kona series) formed in organic material over

pahoehoe lava. Moderately deep or deep Ustifolists (Kaimu and

Mawae series) and moderately deep or deep Udifolists (Puna

and Kiloa series) formed in organic material in fragmental aa

lava. Haplustands (Hanipoe series) and Hydrudands (Manaha`a

series) formed in volcanic ash. The MLRA has a significant

acreage of miscellaneous (nonsoil) areas.

Biological Resources

The vegetation in this area consists of shrubs, grasses, and

trees. The dominant naturalized vegetation at the lower

elevations includes kiawe, bermudagrass, tobacco tree,

fountaingrass, and Natal redtop. A few native herbaceous

species are dominant, including ilima and uhaloa. At the highrainfall, intermediate elevations, naturalized hilograss is

interspersed with native ohia and treefern. At the upper

elevations, kikuyugrass and rattailgrass are the dominant

grazed pasture grasses and ohia and koa are the dominant

native overstory trees. Five critical habitat areas have been

designated within this MLRA for clusters of plants, including

haha (both Cyanea hamatiflora and Cyanea stictophylaa),

popolo ku mai, and hua kuahiwi.

Some of the major wildlife species in the area are feral

mouflon sheep, feral pigs, and numerous species of game

birds. The native wildlife species include the endangered nene,

the endangered Hawaiian hawk, and the endangered Hawaiian

bat.
of the United States 539

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 2%

Grassland—private, 53%

Forest—private, 37%; Federal, 2%

Urban development—private, 2%

Other—private, 4%

The “other” category is dominantly barren lava flows or

cinder cones. Most of this area is rangeland, but forest

dominates the wetter, higher elevation areas. Coffee,

macadamia, avocado, and papaya are grown. Some coastal areas

are used for urban or resort development.

The major resource concerns are the irrigation water supply,

nutrient and pesticide runoff and leaching, and depletion of

organic matter in the soils. Conservation practices on cropland

generally include irrigation water management and nutrient

and pest management. 

Figure 162-1: Location of MLRA 162 in Land Resource Region V.

162—Humid and Very Humid Organic

Soils on Lava Flows

This area is on the Big Island of Hawaii (fig. 162-1). It makes

up about 550 square miles (1,430 square kilometers). The towns

of Hilo, Pahoa, and Kalapana are in this MLRA. Highways 11,

13, 19, 20, and 137 cross the area.

Physiography

This area is on the southeastern slopes of Mauna Loa and

Kilauea volcanoes. Slopes are undulating to very steep and

follow the rugged topography of the lava flows. Elevation

ranges from sea level to 4,000 feet (0 to 1,220 meters). Local

relief ranges from 20 to 100 feet (6 to 30 meters).

The only Hydrologic Unit Area (identified by a four-digit

number) that makes up this MLRA is Hawaii (2001). The area

has numerous streams. The Wailuku River empties into Hilo

Bay in this area.

Geology

This area is covered dominantly by a shallow layer of

organic material in or on basaltic aa or pahoehoe lava bedrock.

Volcanic activity has covered some small areas with recent

volcanic ash.

Climate

The average annual precipitation in this area is 60 to 235

inches (1,525 to 5,970 millimeters). It is higher in the northern

part of the area than in the southern part, and it increases with

elevation. The rainfall occurs from November through April in

udic areas and is evenly distributed in perudic areas. The

average annual temperature is 54 to 73 degrees F (12 to 23

degrees C). The freeze-free period averages 365 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 10%; ground water, 88%

Livestock—surface water, 1%; ground water, 1%

Irrigation—surface water, 0%; ground water, 0%

Other—surface water, 0%; ground water, 0%

The total withdrawals are about 10 million gallons per day

(38 million liters per day). About 89 percent is from ground

water sources, and 11 percent is from surface water sources.

Because of the high amount of rainfall, irrigation is not needed

for crop production. The area has a number of perennial

streams. The chemical quality of the surface water is good, but

physical and biological water quality can be a problem.

Treatment is needed if the water is to be used as drinking water.

All three volcanic rock aquifers on the Big Island of Hawaii

occur in this area. They include the Kau aquifer; the Puna,

Hualalai, Kahuku, and Hamakua aquifer; and the Laupahoehoe

and Hawi aquifer. Tests indicate that the ground water in the

Kau aquifer has a median level of about 100 parts per million

(milligrams per liter) total dissolved solids and is soft. In most

of the area, this water is suitable for almost all uses with little or

no treatment. The level of salts increases in water from these

aquifers in areas near the coast, where the intrusion of seawater

can be a problem if the aquifer is overused. The silica level in

the water from all of the volcanic rock aquifers exceeds 30 parts

per million (milligrams per liter). The level of silica limits the

industrial use of the ground water. At this concentration, silica
540 Major Land Resource Areas

Figure 163-1: Location of MLRA 163 in Land Resource Region V.

combines with calcium and magnesium to form a scale that can

create problems, especially in boilers and steam turbines.

Soils

The dominant soils in this MLRA are Udifolists (Kiloa and

Opihikao series) that have an isothermic or isohyperthermic

soil temperature regime and a perudic or udic soil moisture

regime. They are shallow over pahoehoe or a layer of aa

clinkers. The layer of clinkers can extend to a depth of about 3

feet (1 meter). Hard, massive but fractured basalt underlies this

layer. In some areas aa and pahoehoe lava flows or ash are too

young to have obtained enough organic material for the

formation of soils.

Biological Resources

This MLRA supports herbaceous plants, shrubs, and trees.

The naturalized vegetation includes rose apple tree, African

tuliptree, strawberry guava, and banana poka. The vegetation

on coastal beaches includes coconut palms, ironwood, and

other xerophytic and salt-tolerant plants. Native forests are

dominated by ohia. Critical habitat for clusters of plants has

been designated in the upper watersheds above Hilo and Saddle

Road. The rare or endangered plants in the area include oha wai

(Cleremontia peleana), haha (Cyanea platyphylla), and

ha ́iwale (Cyrtandra tintinnabula).

Some of the major wildlife species in this area are

endangered waterfowl in wetlands and streams, such as the

Hawaiian stilt, coot, moorhen, and duck. Nene, hoary bat, and

Hawaiian hawk in pastures, abandoned areas formerly used for

sugarcane, and lava fields are in unique anchialine pools (pools

in marine caves) along the coastline. Rare shrimp species also

occur in these areas.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 2%

Grassland—private, 25%; Federal, 1%

Forest—private, 54%; Federal, 2%

Urban—private, 2%;

Other—private, 12%; Federal, 2%

Naturalized forest makes up most of this area. The forestland

is used for grazing, recreation, wildlife habitat, and watershed.

Some areas are used for woodland with planted trees or for

pasture or orchards.

The major resource concerns are the spread of invasive plant

species, depletion of organic matter in the soils, and

contamination caused by fertilizers, pesticides, and rural wastedisposal systems. Conservation practices on cropland and

rangeland generally include mulching, crop residue

management, and nutrient and pesticide management.

Practices that reduce the extent of invasive species also are

important. 

163—Alluvial Fans and Coastal Plains

This area is in the Hawaiian Islands (fig. 163-1). It makes up

about 140 square miles (365 square kilometers). It includes the

towns or cities of Kahului, Maui; Kailua, Pearl City, and

Honolulu, Oahu; and Mana, Kauai. There are numerous

highways throughout these mostly heavily populated areas,

including Interstate H1. Hickam Air Force Base, Pearl Harbor

Naval Reservation, Kaneohe Bay Marine Corps Base, and the

Pacific Missile Range Facility are some of the larger military

installations in this MLRA. Captain James Cook landed near

the mouth of the Waimea River in the part of this area on Kauai.

Physiography

This area is on nearly level and gently sloping coastal plains

and the adjacent alluvial fans. Elevation ranges from sea level

to 200 feet (0 to 60 meters). Local relief ranges from 50 to 100

feet (15 to 30 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Oahu (2006), 61 percent; Maui (2002), 27 percent; and Kauai

(2007), 12 percent. Numerous streams cross the area as they

empty into the ocean. Very few of the streams are perennial. The

Waimea River is the only perennial stream in the part of this

area on Kauai.
of the United States 541

Geology

Alluvial fans and terraces grade into coastal plains

throughout this area. Basalt, coral limestone, calcareous sand

deposits, volcanic ash, coral sand, and fill lie beneath the

unconsolidated sediments. Some small areas on coastal plains

are underlain by marly lagoon deposits and marine clays.

Climate

The average annual precipitation in this area is 20 to 30

inches (510 to 760 millimeters). Most of the rainfall occurs

from November through March. It occurs during kona storms

that come in from the leeward side of the islands. The average

annual temperature is 72 to 76 degrees F (22 to 24 degrees C).

The freeze-free period averages 365 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 2.1%; ground water, 42.9%

Livestock—surface water, 0.0%; ground water, 0.0%

Irrigation—surface water, 18.2%; ground water, 6.3%

Other—surface water, 2.8%; ground water, 27.7%

The total withdrawals average 395 million gallons per day

(1,495 million liters per day). About 77 percent is from ground

water sources, and 23 percent is from surface water sources. The

amount of rainfall is not adequate for crop production without

irrigation. The area has only a few perennial streams. Some

surface water is trapped in catchments in the higher and wetter

parts of this MLRA and is piped to lower areas, where it is used

for watering livestock and for irrigation. Some irrigation water

is imported from the adjacent MLRAs. The surface water

generally is not suitable for drinking unless it is treated.

Most of the water used in this area is ground water, which is

of better quality than the surface water. Most of the water on

Oahu is pumped from alluvial aquifers and the Waianae and

Honolulu volcanic rock aquifer. This water typically has a

median level of total dissolved solids of about 200 parts per

million (milligrams per liter) and is moderately hard. Ground

water is pumped from sedimentary deposits in the isthmus area

of Maui for use in this MLRA. There are no water-quality test

data reported for this aquifer. The intrusion of seawater is a

potential problem in the aquifers on both of these islands.

Because of population increases, agricultural land has been

converted to urban uses in southern Oahu. The improved

drainage system in the urbanized areas carries runoff water

away from recharge areas for the local aquifers. Also, recharge

no longer occurs from the application of irrigation water after

the agricultural land is developed for urban uses. Because of

the lack of recharge and the heavy pumping near the coast, the

level of ground water has dropped and the water has become

more salty over time.

Soils

The dominant soil orders in this MLRA are Mollisols,

Aridisols, Entisols, and Vertisols. The soils in the area have an

isohyperthermic soil temperature regime, an aquic or arid

(torric) soil moisture regime, and kaolinitic, carbonatic,

parasesquic, smectitic, or mixed mineralogy. They are very

deep to shallow, excessively drained to poorly drained, and

clayey. Haplustolls (Ewa series) formed in alluvium derived

from basaltic rocks. Ustipsamments (Jaucas series) formed in

calcareous sand deposits in vegetated back-beach areas.

Haplocambids (Kekaha series) and Gypsitorrerts (Lualualei)

formed in fine textured alluvium derived from basic igneous

rocks. Haplocambids (Mamala series) also formed in shallow

alluvium over coral limestone on coastal plains. Haplustolls

(Mokuleia series) formed in recent alluvium over coral sand.

Near sea level, Endoaquolls (Nohili series) formed in alluvium

underlain by marly lagoon deposits. The MLRA has some

miscellaneous (nonsoil) areas.

Biological Resources

This area supports herbaceous and shrub vegetation and

some trees. The naturalized vegetation consists of fingergrass,

kiawe, koa-haoe, klu, lantana, and bermudagrass. The

vegetation on coastal beaches includes coconut palms,

ironwood, and other xerophytic and salt-tolerant plants.

Wetlands support pickleweed, napiergrass, guava, and

California grass.

Some of the major native wildlife species in this MLRA

inhabit wetlands. They include the endangered stilts, the

endangered coot, and the endangered moorhen. The

Kaneohe Bay Marine Corps Base on Oahu has a refuge area

for the endangered red-footed booby. The naturalized animals

in the MLRA include numerous game bird species and

chickens.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 20%

Grassland—private, 21%; Federal, 12%

Forest—private, 2%; Federal, 1%

Urban development—private, 27%; Federal, 8%

Water—private, 1%

Other—private, 7%; Federal, 1%

Most of the part of this MLRA on Oahu is in urban areas or

military installations. The crops grown in the MLRA include

irrigated sugarcane, truck crops, and orchards. Some small areas
542 Major Land Resource Areas

Figure 164-1: Location of MLRA 164 in Land Resource Region V.

are used for dry-farmed pasture. Some coastal areas are used for

resort development.

The major resource concerns are nutrient and pesticide

leaching near shore environments, invasive plants and animals

in wetlands, tillage-induced surface compaction, wind erosion,

water erosion, and the supply and efficient use of irrigation

water. Conservation practices on cropland and rangeland

generally include nutrient and pest management, management

of wildlife habitat, proper tillage, subsoiling, properly designed

irrigation systems, windbreaks, and cover crops. Urban stormwater management in the heavily urbanized areas and on the

military installations helps to protect streams, wetlands, and

coastal zones. 

164—Humid and Very Humid Steep and

Very Steep Mountain Slopes

This area is in the Hawaiian Islands (fig. 164-1). It makes up

about 760 square miles (1,970 square kilometers). It has only a

few populated areas, including the coastal towns of Hanalei,

Kauai; Kalaupapa and Halawa, Molokai; and Kahakuloa and

Keanae, Maui. The part of the MLRA on Kauai includes Mt.

Waialeale, noted as one of the highest rainfall areas on earth.

Physiography

This MLRA consists primarily of the deeply dissected

mountainous areas of the older Hawaiian Islands. The

topography is steep to precipitous and has many ridges,

gulches, and canyons. Plateaus supporting montane bogs occur

on the islands of Kauai, Molokai, Maui, and Hawaii. Elevation

ranges from sea level to 7,000 feet (0 to 2,135 meters). Local

relief is mostly 2,000 to 4,000 feet (610 to 1,220 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Kauai (2007), 33 percent; Maui (2002), 25 percent; Oahu

(2006), 18 percent; Molokai (2005), 12 percent; and Hawaii

(2001), 12 percent. The headwaters of many streams form in this

steep area, and perennial streams are common.

Geology

This area is underlain by fractured basic igneous rock that is

slightly weathered to highly weathered. Most of the bedrock is

basalt. Volcanic ash and tropospheric dust are deposited in

some areas. Organic deposits occur in wet forests at the higher

elevations.

Climate

The average annual precipitation in most of this area is 75 to

250 inches (1,905 to 6,350 millimeters). It can be as low as 30

inches (760 millimeters) in some of the coastal areas below

mountains and as much as 450 inches (11,430 millimeters) at

the highest elevations. Most of the rainfall occurs from

November through April. The average annual temperature is 53

to 75 degrees F (12 to 24 degrees C). The freeze-free period

averages 365 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0%; ground water, 0%

Livestock—surface water, 50%; ground water, 0%

Irrigation—surface water, 0%; ground water, 0%

Other—surface water, 50%; ground water, 0%

The total withdrawals average 0.2 million gallons per day

(0.8 million liters per day). All of the water is surface water. This

high-rainfall area has many perennial streams. It is primarily an

area of ground water recharge for all of the islands on which it

occurs. This dominantly forested area has only a small acreage

of agricultural land, and most of the water is used for domestic

purposes or for watering livestock. Catchments are used to trap

water, which is stored in tanks for future use.

Soils

The dominant soil orders in this MLRA are Inceptisols,

Andisols, and Spodosols. The soils in the area have an

isothermic or isomesic soil temperature regime, an aquic to

ustic soil moisture regime, and mixed, amorphic, ferrihydritic,

or parasesquic mineralogy. They generally are deep, are poorly

drained to well drained, and have fine, very fine, medial, and

hydrous textures. The soils on plateaus have an organic surface

layer. The plateaus have unique montane bogs with perched
of the United States 543

water caused by an ironstone sheath within the soils.

Petraquepts (Amalu and Hula series) and Placorthods (Kahanui

series) formed in organic material, volcanic ash, and

tropospheric dust over basic igneous rock. Poorly drained

Epiaquands (Koolau series) and shallow, poorly drained

Epiaquepts (Olokui series) also occur in the area. Hydrudands

(Honomanu series) formed in weathered volcanic ash, which

overlies fragmented basic igneous rock. The MLRA has a

significant acreage of miscellaneous (nonsoil) areas.

Biological Resources

This area is dominated by the Oreobolus furcatus (no

common name) montane rain forest, which has mixed plant

species. Montane bog vegetation is common in the rain forests.

The more common plants in the bogs are wet sedges, ohia,

na ́ene ́e (Dubautia waialealae), and `uki. Numerous critical

habitat plant cluster areas are in this MLRA. The rare and

endangered plants in the part of the MLRA on Kauai include

Domin’s club, mapele, heau, Poa siphonoglossa (no common

name), Alsidendron viscosum (no common name), and haha

(Cyanea asarifolia). The plants in the part of the area on Oahu

include nanu, alani (Melicope lydgatei), `oha (Delissea

subcordata), `anini or wanini, and nioi. The plants in the part

on Molokai include alani (Melicope reflexa), haha (Cyanea

grimesiana), ko`oko`olau, Lysimachia maxima (no common

name), and Stenogyne bifida (no common name). The plants in

the part on Maui include Pteris lydgatei (no common name),

ha`iwale (Cyrtandra munroi), oha wai, and a variety of pauoa

and haha species.

Some of the major wildlife species in the area include rare

honeycreepers and other native Hawaiian forest birds

(particularly on Kauai, which is inhabited by the `Akikiki

Kaua ́i elepaio, Kaua ́i amakihi, `anianiau, and `akeke ́e). The

endangered animals in this MLRA include the Newcomb’s snail

on Kauai, Blackburn’s sphinx moth on Molokai, Oahu elepaio

and Oahu tree snails on Oahu, and Achatinellid land snails on

Oahu and Maui. The naturalized species include exotic birds,

feral pigs, deer, and goats.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—private, 50%; Federal, 2%

Forest—private, 43%; Federal, 3%

Urban development—private, 1%

Other—private, 1%

Most of this area is rangeland. Much of the area is

naturalized rain forest. The forestland is used mainly for

watershed, wildlife habitat, and recreation. Some small areas are

used for crops or pasture.

The major soil resource concern is water erosion, including

mass movement. Conservation practices on forestland include

native forest restoration and fencing, which helps to control

feral animals. 

165—Subhumid Intermediate Mountain

Slopes

This area is in the Hawaiian Islands (fig. 165-1). It makes up

about 110 square miles (290 square kilometers). It has very few

populated areas. Highway 55 skirts the eastern edge of the west

leg of this area on the island of Kauai. Highway 78 crosses the

part of this area on Oahu, and Highway 47 ends in the part on

Molokai.

Physiography

This area is on the leeward, drier, intermediate mountain

slopes of the older Hawaiian Islands. Slopes are rolling and are

dissected by many steep and very steep gulches. Elevation

ranges from 400 to 3,700 feet (120 to 1,130 meters). Local relief

ranges from 200 to 1,800 feet (60 to 550 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Oahu (2006), 49 percent; Kauai (2007), 29 percent; and

Molokai (2005), 22 percent. The headwaters of many streams

are in this area.

Geology

This area is dominated by basic igneous rock (primarily

basalt). Interfluves are influenced by volcanic ash.

Figure 165-1: Location of MLRA 165 in Land Resource Region V.
544 Major Land Resource Areas

Climate

The average annual precipitation in this area is 25 to 60

inches (635 to 1,525 millimeters). Most of the rainfall occurs

from November through March. The average annual

temperature is 61 to 74 degrees F (16 to 23 degrees C). The

freeze-free period averages 365 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 6.7%; ground water, 13.3%

Livestock—surface water, 13.3%; ground water, 0.0%

Irrigation—surface water, 13.3%; ground water, 33.3%

Other—surface water, 6.7%; ground water, 13.3%

The total withdrawals average 1.5 million gallons per day

(5.7 million liters per day). About 60 percent is from ground

water sources, and 40 percent is from surface water sources. The

amount of rainfall is not adequate for crop production without

irrigation. The streams that feed the Waimea River, the only

perennial stream on Kauai, originate in this area. Water for

almost all irrigation and livestock use is imported into this

MLRA from wetter areas.

The Napali volcanic rock aquifer and the Waianae and

Honolulu volcanic rock aquifer on Kauai and Oahu,

respectively, provide good-quality ground water suitable for

almost all uses in this area. Rural landowners use these aquifers

for domestic and livestock water and for irrigation water. Some

public supplies also are obtained from these aquifers.

Soils

The dominant soil orders in this MLRA are Inceptisols,

Ultisols, Oxisols, Andisols, and Spodosols. The soils in the area

have an isothermic soil temperature regime, a udic or ustic soil

moisture regime, and parasesquic, ferrihydritic, or mixed

mineralogy. They generally are deep, well drained, and fine

textured or very fine textured. The soils that formed in volcanic

ash include Haplustox (Mahana series). Haplustands (Oli series)

formed in material weathered from basalt, and Hapludands

(Kokee series) formed on dissected uplands. Placorthods

(Kahanui series) formed in andesite residuum. Palehumults

(Kalae series) formed in alluvium influenced by volcanic ash.

Epiaquepts (Olokui series) are shallow, poorly drained soils that

formed in material weathered from basic igneous rock. The

MLRA has a significant acreage of miscellaneous (nonsoil)

areas.

Biological Resources

This area supports forest, grassland, and scrub-shrub

vegetation. The naturalized vegetation in the areas of lower

rainfall includes kiawe, koa-haole, klu, lantana, and

bermudagrass. Ohia, treefern, and uluhe dominate mesic to wet

areas. Numerous critical habitat plant clusters occur on each

island in this MLRA. On Kauai, the endangered plants that

receive special protection include Abutilon sandwicense (no

common name), alani (Melicope pallida), Schiedea hookeri (no

common name), different species of haha, and aiea

(Nothocestrum pelitatum). On Oahu, they include kulu ́i, nioi,

Ma`o hau hele (native yellow hibiscus), Abutilon sandwicense

(no common name), alani (Melicope pallida), and various

Schiedea species (no common names). The plants on Molokai

include Mariscus fauriei (no common name), various Schiedea

species (no common names), and Silene alexandri (no common

name).

The naturalized wildlife species in this area include feral

pigs, goats, chickens, and game birds. The endangered wildlife

species include the Blackburn’s sphinx moth, which has

designated critical habitat in the part of this MLRA on

Molokai. The hoary bat, Oahu tree snail, and Amastid land

snail are endangered species in the part of the MRLA on

Kauai.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 1%

Grassland—private, 65%; Federal, 6%

Forest—private, 25%; Federal, 2%

Urban development—private, 1%

Forest and rangeland make up nearly all of this area. Most of

the area is used for watershed for the adjacent MLRAs. Some

small areas are used for irrigated coffee or pineapple crops.

The major resource concerns are invasive species, feral

animals, and water erosion. Conservation practices that are

important in the area generally include restoration of native

wildlife habitat, erosion control, and fencing, which helps to

control feral animals. 

166—Very Stony Land and Rock Land

This area is in the Hawaiian Islands (fig. 166-1). It makes up

about 445 square miles (1,160 square kilometers). The part of

this area on Kauai has no towns. On Kauai, Highway 55 is on

the western edge of the MLRA, where the area shares a

boundary with MLRA 165. The towns of Portlock and Aina

Haina are in the eastern part of this area on Oahu, and Highway

72 connects these towns with Honolulu. Highway 78 crosses

the middle of the western part of this area on Oahu. The town of

Makua and Highways 90 and 99 also occur in the western part

of this area, on the northwest tip of Oahu. The towns of Kamalo

and Kaunakakai and Highway 45 are in the part of this area on
of the United States 545

Figure 166-1: Location of MLRA 166 in Land Resource Region V.

the south coast of Molokai. The town of Kaumalapau Harbor

and Highways 44 and 441 are in the part of this area on Lanai.

The town of Olowalu and Highway 30 are in the western part of

this area on Maui. The town of Keoneoio and Highway 31 are

in the eastern part of this area on Maui. The U.S. Navy

Bombing Range is in the part of this area on the uninhabited

island of Kahoolawe.

Physiography

This area encompasses the stony complex slopes and rocky

gulches in the arid and semiarid areas of the older Hawaiian

Islands. Elevation ranges from sea level to 8,000 feet (0 to

2,440 meters). Local relief ranges from 200 to 2,000 feet (60 to

610 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Maui (2002), 23 percent; Lanai (2004), 22 percent; Oahu

(2006), 15 percent; Niihau (2008), 13 percent; Molokai (2005),

12 percent; Kahoolawe (2003), 8 percent; and Kauai (2007), 7

percent. The Waimea River, the only perennial stream on Kauai,

is in this area.

Geology

This area is covered by extrusive basic igneous rocks

(primarily basalt) that are weathered in some areas. Some

interfluves are mantled with weathered volcanic ash.

Climate

The average annual precipitation in this area is 10 to 60

inches (255 to 1,525 millimeters). Most of the rainfall occurs

from November through March. Much of it occurs during kona

storms. The average annual temperature is 50 to 76 degrees F

(10 to 24 degrees C). The freeze-free period averages 365 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.6%; ground water, 42.9%

Livestock—surface water, 4.0%; ground water, 2.9%

Irrigation—surface water, 2.9%; ground water, 11.4%

Other—surface water, 0.0%; ground water, 35.4%

The total withdrawals average 17.5 million gallons per day

(65 million liters per day). About 93 percent is from ground

water sources, and 7 percent is from surface water sources. The

amount of rainfall is not adequate for crop production without

irrigation. The only perennial stream on Kauai, the Waimea

River, is in this area. Because of the steep walls of the canyon

through which the river flows, accessing the river water is

difficult. Water for almost all irrigation and livestock use is

imported into this MLRA.

Almost all of the water used in this area is for domestic,

public, municipal, or industrial supplies. This water comes from

volcanic rock aquifers. All of the volcanic rock and alluvial or

sedimentary aquifers on Kauai, Oahu, Molokai, Maui, and the

minor islands occur in this area. Some rural landowners use

these aquifers for domestic and livestock water and some

limited irrigation, but most of the ground water is used for

public supply or for municipal or industrial purposes.

Soils

The dominant soil orders in this MLRA are Aridisols,

Mollisols, and Entisols. The soils in the area have an

isohyperthermic soil temperature regime, an aridic or ustic soil

moisture regime, and dominantly mixed mineralogy. They

dominantly are shallow, well drained, and clayey. They formed

in material weathered from basic igneous rocks. Stony, shallow

Haplocambids (Waiawa series) and Haplustolls (Waikomo

series) and shallow Ustorthents (Uma series) occur in many

areas. The MLRA has a significant acreage of miscellaneous

(nonsoil) areas. Rock outcrops or stones cover the surface in

about 40 to 50 percent of the area.

Biological Resources

The lower elevations of all of the islands in this MLRA

support naturalized grass and scrub-shrub vegetation. These

plants include Christmasberry, guineagrass, bermudagrass, and

Natal redtop. Many areas in the MLRA are designated as

critical habitat for endangered plants. Critical area plant

clusters include Panicum beechey (no common name),

Schiedea spergulina spergulina (no common name), `akoko
546 Major Land Resource Areas

167—Humid Oxidic Soils on Low and

Intermediate Rolling Mountain Slopes

This area is in the Hawaiian Islands (fig. 167-1). It makes up

about 230 square miles (595 square kilometers). The part of this

area on Kauai has no towns. Highway 55 crosses the northern

part of the MLRA on this island, Highway 581 skirts the eastern

edge of the southern part, and Highway 50 crosses the

southernmost end. Highway 83 connects the many towns in the

part of this area on the east coast of Oahu. The towns of

Pauwela and Kokomo and Highways 36 and 40 are in the part

on Maui.

Physiography

This area is dominantly on windward, low and intermediate

mountain and hill slopes of the older Hawaiian Islands. Many

steep and very steep gulches dissect the rolling mountain

slopes. Elevation ranges from sea level to 2,000 feet (0 to 610

(Chamaesyce halemanui), nehe (Lipochaeta faurei), kaula, and

Gouania meyernii (no common name) on Kauai; kio ́ele,

Bonamia menzesii (no common name), `awiwi, `anaunau, and

Silene lanceolata (no common name) on Oahu; Wahine noho

kula, `ohai, and ma`o hau hele on Molokai; Tetramolopium

remyi (no common name), ma`o hau hele, and `ohai on Lanai;

and ko`oko`olau (Bidens micrantha kalealaha), Bobea

sandwicensis (no common name), Bonamia menziesii (no

common name), and a ́e (Zanthoxylum hawaiiense) on Maui.

Naturalized game birds, feral pigs, deer, and goats inhabit

this MLRA. Many pelagic bird species, such as the Laysan

albatross, shearwaters, and petrels, are along the coast and on

nearby islets. Some of the major endangered wildlife species in

the area are pueo and hoary bat on Oahu and Blackburn’s

sphinx moth and nene on Maui.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—private, 77%; Federal, 2%

Forest—private, 4%

Urban development—private, 3%

Water—private, 1%

Other—private, 13%

Most of this MLRA is used for rangeland, watershed, and

wildlife habitat. More than one-fifth of the area is forestland. A

small acreage is used for urban development.

The major resource concerns are control of flooding, fire,

wind erosion, water erosion, and feral animals and restoration of

native plant species. Conservation practices on rangeland

generally include prescribed grazing, fencing, watering

facilities, and firebreaks. 

Figure 167-1: Location of MLRA 167 in Land Resource Region V.

meters). Local relief ranges from 100 to 700 feet (30 to 215

meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Oahu (2006), 60 percent; Kauai (2007), 21 percent; and Maui

(2002), 19 percent. The headwaters of many streams occur in

this area.

Geology

This area is covered dominantly by highly weathered ash

and basic igneous rock. Alluvial sediments occur on bottom

lands and low terraces along streams. In some small areas, the

dominant geology is influenced by tropospheric dust.

Climate

The average annual precipitation in this area is 35 to 120

inches (890 to 3,050 millimeters). It increases with elevation.

Most of the rainfall occurs from November through April. The

average annual temperature is 66 to 76 degrees F (19 to 24

degrees C). The freeze-free period averages 365 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 0.0%; ground water, 42.5%

Livestock—surface water, 3.9%; ground water, 3.3%

Irrigation—surface water, 3.3%; ground water, 5.9%

Other—surface water, 2.6%; ground water, 38.6%

The total withdrawals average 15 million gallons per day

(55 million liters per day). About 90 percent is from ground

water sources, and 10 percent is from surface water sources. The
of the United States 547

amount of rainfall is not adequate for crop production without

irrigation. The area has a few perennial streams but has no

natural storage areas for surface runoff. Because of physical and

biological contamination, rural landowners use the surface

water only as livestock water and for some irrigation.

Almost all of the water used in this area is for domestic,

public, municipal, and industrial supplies. Ground water of

suitable quality for almost all uses on Kauai can be obtained

from the Koloa and Olokele volcanic aquifer and the

sedimentary rocks. The median level of total dissolved solids is

generally less than 500 parts per million (milligrams per liter)

in each of these aquifers, but the water in the volcanic aquifer is

very hard and requires some treatment prior to use for domestic

and public supplies. Good-quality ground water for most uses

can be obtained from the Koolau volcanic aquifer, alluvial

sediments, and sedimentary rocks on Oahu. The median level of

total dissolved solids is less than 200 parts per million

(milligrams per liter) in these aquifers, and the water in the

volcanic aquifers is soft, so little treatment is required before

the water is used as drinking water. Poor-quality ground water

can be obtained from the Kula volcanic aquifer on Maui. The

median level of total dissolved solids is close to 1,000 parts per

million (milligrams per liter), and the water is very hard.

Because of the poor water quality, the ground water on Maui is

used primarily as livestock and irrigation water.

Soils

The dominant soil orders in this MLRA are Ultisols, Oxisols,

and Inceptisols. The soils in the area have an isohyperthermic

soil temperature regime, a udic or ustic soil moisture regime,

and dominantly ferritic, ferruginous, mixed, parasesquic,

kaolinitic, or sesquic mineralogy. They generally are very deep,

well drained, and very fine textured. The soils on bottom land

are well drained to poorly drained. The soils that formed in

alluvial material include Endoaquepts (Hanalei series),

Natraquerts (Kaena series), and Haplustolls (Waialua series).

The soils that formed in areas influenced by tropospheric dust

include Palehumults (Haiku series) and Acrudox (Makapili

series). The soils that formed in material weathered from basic

igneous rock include very deep and deep Palehumults

(Honolua, Ioleau, and Kalapa series), Kanhaplohumults

(Pauwela series), and Acrudox (Kapaa and Pooku series). The

soils that formed in material weathered from basic igneous rock

with admixtures of volcanic ash and ejecta include Acroperox

(Halii series). The MLRA has a significant acreage of

miscellaneous (nonsoil) areas.

Biological Resources

This area supports mesic to wet grass and forest vegetation

and wetland plants. The naturalized plants include hilograss,

California grass, java plum, and guava. Some areas are

designated as critical habitat for endangered plants. Critical

area plant clusters include Awaous guamensis (no common

name), Atyoida bisulcata (no common name), and Hedyotis

littoralis (no common name) on Kauai and different species of

haha, aupaka (Isodendrion longifolium), and Schiedea kaalae

(no common name) on Oahu. Critical habitat for aspleniumleaved Diellia is in the part of this MLRA on Maui.

Some of the major wildlife species in the area are hoary bat

on all three islands and Oahu elepaio on Oahu. The endangered

Hawaiian coot, stilt, and moorhen are on wetlands in the parts

of this area on Kauai and Oahu. Small colonies of the

endangered Newell shearwater and the endangered Hawaiian

duck are in the part on Kauai.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 7%

Grassland—private, 41%; Federal, 4%

Forest—private, 37%; Federal, 2%

Urban development—private, 7%

Water—private, 1%

Other—private, 1%

Rangeland and woodland make up most of this area. About

one-third of the area is used for bananas, pineapples, sugarcane,

pasture, taro, orchards, or other crops. Some coastal areas are

used for urban or resort development.

The major resource concerns are the spread of invasive plant

species, flooding, and beach and water erosion. Wind erosion is

a concern in the Kahuku area on Oahu. Conservation practices

on rangeland and cropland generally include nutrient and pest

management, restoration of native plants, prescribed grazing,

crop rotations, and windbreaks. 

549

Figure W1-1: Location of Land Resource Region W1.

W1—Southern Alaska

This region is in the southern part of Alaska (fig. W1-1). It

includes the arc of coastal lowlands and mountains along the

Gulf of Alaska from the Alexander Archipelago in the southeast

to Kodiak Island and the southern portion of the Alaska

Peninsula in the west. It also includes the lowlands and

mountains of Cook Inlet. The region makes up 95,210 square

miles (246,710 square kilometers).

Rolling hills, glacial moraines, alluvial fans, and large

outwash plains extend from the mountains to the commonly

rugged coastline. All of the rivers in the region drain into the

Gulf of Alaska and the North Pacific. Broad flood plains,

terraces, and deltas flank the numerous glacial and freshwater

drainages. Elevation ranges from sea level along the coast to

20,320 feet (6,195 meters) at the summit of Mount McKinley.

The higher elevations are in areas of rugged mountains with

bare rock, talus, glaciers, and ice fields. Some permafrost occurs

in small isolated depressions and on north-facing slopes in the

northern portion of the region.

The climate in this region ranges from maritime at the lower

elevations along the coast to transitional maritime-continental

at the higher elevations and in the northern Cook Inlet

Lowlands. The average annual precipitation ranges from about

15 inches (380 millimeters) in the central Cook Inlet Lowlands

to more than 275 inches (6,985 millimeters) in the coastal

mountains. The average annual snowfall ranges from 30 to 70

inches (75 to 180 centimeters) along the coast and is as much as

800 inches (205 centimeters) in the high mountains. The

average annual air temperature ranges from 27 to 46 degrees F

(-3 to 8 degrees C). Temperatures are warmer near the coast and

in the Cook Inlet Basin. Daily and seasonal temperature

variations are highest in the mountains. The freeze-free period

ranges from less than 60 days to more than 140 days.

The total withdrawals of freshwater in this region average

about 230 million gallons per day (870 million liters per day).

About 78 percent is from surface water sources, and 22 percent

is from ground water sources. About 80 percent of the

freshwater used in Alaska is used in this region, which is the

most densely populated area in Alaska. About 65 percent of the

water is used to meet the needs of the seafood industry, pulp

mills, and mines or is used for cooling thermoelectric power

plants. The rest of the freshwater is used primarily for public

supply.
550 Major Land Resource Areas

Figure W1-2: Agricultural development in an area of Land Resource Region W1.

The soils in this region dominantly have a cryic soil

temperature regime, an aquic or udic soil moisture regime, and

mixed or amorphic mineralogy. Gelepts and Cryepts occur on

steep mountain slopes. Cryods, Cryands, Aquands, and Cryepts

are on the lower slopes, foothills, and moraines. While

Spodosols and Andisols intergrade in some areas, Andisols are

dominant in the areas closer to volcanic sources. These areas

include the Alaska Peninsula, Kodiak Island, the southern

Kenai Peninsula, Kruzof Island, and Baranof Island. The

Cryepts on the younger surfaces include Eutrocryepts and

Dystrocryepts. Fluvents and Aquents are dominant on flood

plains and low terraces. Histosols and Histic subgroups of other

orders occur throughout the region. They are on level and

depressional landforms and even on the steeper slopes along

the coast and in the southeast. The Histosols include Fibrists,

Hemists, Saprists, and Folists.

Alpine and subalpine vegetation occurs on the mountain

slopes in this region. The vegetation transitions into subalpine

grasslands and tall scrub at the lower elevations. The lower

elevations of the Cook Inlet Lowlands have mixed forests of

white spruce, black spruce, paper birch, and willow. Stunted

black spruce grades into scrub and herbaceous communities in

fens and bogs. Coastal forests dominated by Sitka spruce are

along the northern and northwestern parts of the Gulf of Alaska.

Western hemlock and Sitka spruce forests are dominant in the

southeastern part of the region, and red cedar and Alaska cedar

occur in the area farthest south. Land use is very diverse and

includes urban and rural development, agriculture (fig. W1-2),

forestry, commercial fishing, mining, livestock grazing,

subsistence hunting and fishing, recreation, and wildlife

habitat. 
of the United States 551

Figure 220-1: Location of MLRA 220 in Land Resource Region W1.

220—Alexander Archipelago-Gulf of

Alaska Coast

This area is in the Southern Alaska Region (fig. 220-1). It

includes the narrow arc of islands and low coastal mountains

from the Alexander Archipelago in southeastern Alaska, north

and west along the coast of the Gulf of Alaska and Prince

William Sound, to the southern tip of the Kenai Peninsula. The

area makes up about 27,435 square miles (71,085 square

kilometers). The municipality of Juneau, Alaska’s capital, and

Ketchikan and Sitka are in the eastern part of the area. A

number of smaller coastal towns and villages also are in the

area. The Admiralty Island National Monument and part of

Misty Fjords National Monument, Tongass National Forest,

Chugach National Forest, and Glacier Bay, Wrangell-St. Elias,

and Kenai Fjords National Parks and Preserves are in this

MLRA. The southern terminus of the Trans-Alaska Pipeline is

in this area, in Valdez.

Physiography

This area lies within the Pacific Border Ranges, Coastal

Mountains, and Coastal Trough Provinces of the Pacific

Mountains System. The Alexander Archipelago, Prince William

Sound, and the southern Kenai Peninsula have dominantly low

to moderate relief and deeply incised mountains. Throughout

the area glaciers, rivers, and streams have cut deep, narrow to

broad valleys. The broader valleys have nearly level to strongly

sloping flood plains and stream terraces. Alluvial and colluvial

fans and short footslopes are common in the valleys along the

base of the mountains. Rocky headlands and sea cliffs are

common along the coast. In the central portion of the area, the

terrain consists primarily of strongly sloping to moderately

steep outwash plains, alluvial fans, long footslopes, and flood

plains. Formed by meltwaters of glaciers and ice fields from the

adjoining MLRA 222, the flood plains in this part of the

area are generally broad, have a high gradient, and are

braided. Elevation ranges from sea level to 4,665 feet (1,420

meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Southeast Alaska (1906), 83 percent, and South Central Alaska

(1905), 17 percent. Surface water in this area drains to the Gulf

of Alaska and the North Pacific by way of numerous short, highgradient rivers that originate in glaciers, ice fields, mountain

uplands, and the interior of Alaska and British Columbia. The

major rivers are the Copper, Alsek, Taku, and Stikine Rivers.

Lakes make up less than 2 percent of the area. Glaciers make up

less than 1 percent and are limited to the higher elevations on

Baranof Island in the Alexander Archipelago.

Geology

During the late Pleistocene epoch, the entire area was

covered with glacial ice. The numerous fjords of the Alexander

Archipelago and Prince William Sound were formed along

faults or joints, chiefly as a result of glacial scouring and

deepening of preglacial river valleys. Most glacial deposits

have been eroded away or buried by mountain colluvium and

alluvium, which cover about 90 percent of the present

landscape. The remaining glacial and glaciofluvial deposits are

generally restricted to coastal areas. During the Holocene

epoch, volcanic activity within and adjacent to this area

deposited a layer of volcanic ash of varying thickness on much

of the landscape in the southeastern and northwestern parts of

the area. Paleozoic, Mesozoic, and Lower Tertiary stratified

sedimentary rocks and Cretaceous and Tertiary intrusive rocks

underlie much of the area and are exposed on steep mountain

slopes and ridges.

Climate

The average annual precipitation in most of this area is 60 to

120 inches (1,525 to 3,050 millimeters). It is 15 to 25 inches

(380 to 635 millimeters) at the lower elevations on the small

part of the Cook Inlet Lowlands in the southwest corner of the

area. It can be as much as 200 inches (5,080 millimeters) at the

highest elevations. Cloudy skies, moderate temperatures, and

abundant rainfall characterize the temperate maritime climate

of this area. Winter storms, accompanied by heavy rainfall at

the lower elevations and snow at the higher elevations, are

frequent. Moderate to strong, south and southeast winds are

common before and during the storms. The average annual

snowfall ranges from about 30 to 70 inches (75 to 180

centimeters) along the coast and is as much as 200 inches (510

centimeters) at the higher elevations. The average annual

temperature at the lower elevations ranges from about 37
552 Major Land Resource Areas

degrees F (3 degrees C) in the northwestern part of the area to

46 degrees F (8 degrees C) in the southeastern part. The freezefree period averages about 120 to 190 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 15.3%; ground water, 13.2%

Livestock—surface water, 0.2%; ground water, 0.0%

Irrigation—surface water, 0.4%; ground water, 0.0%

Other—surface water, 50.4%; ground water, 20.5%

The total withdrawals average 53 million gallons per day

(200 million liters per day). About 34 percent is from ground

water sources, and 66 percent is from surface water sources. In

most years precipitation is adequate for crops, but in some years

yields are reduced by short dry periods in summer. Permanent

streams, originating in the mountainous regions on the inland

side, carry water to nearly all parts of the area. Some outlets for

natural lakes in this area have been dammed. The stored water

is used for limited irrigation, public supply, pulp mills in Sitka

and Ketchikan, and fish-processing plants. The surface water is

generally suitable for all uses. Rivers fed by glacial meltwater

typically carry high loads of suspended sediment. The

development of small local streams around Juneau is being

considered. These streams would supplement the public water

supply in developing areas outside Juneau. Flooding from ice

dams that form during the spring thaw is a concern in this area.

Ground water is used for some public supply, pulp mills in

Sitka and Ketchikan, and fish-processing plants in the central

part of the area and in the vicinity of Juneau. The water is

pumped primarily from unconsolidated sediments in river

valleys (alluvium) or from buried glacial outwash deposits in

the river valleys or on uplands. It is hard or very hard but is

otherwise of excellent quality. Wells in this aquifer generally

are shallow, and the aquifer is being constantly recharged with

freshwater (rainfall and runoff). As a result, the median level of

total dissolved solids is fairly low, about 130 parts per million

(milligrams per liter). The level of iron may exceed the

secondary standard for drinking water of 300 parts per billion

(micrograms per liter). This standard is for esthetics. The iron

can stain ceramic and porcelain and precipitate in pipes. Since

this aquifer is close to the surface and water moves through it

quickly, it is highly susceptible to contamination from runoff.

Septic systems, landfills, and leaking fuel storage tanks are all

possible sources of contamination. The intrusion of seawater

can be a problem along the coast.

Small amounts of ground water can be obtained from the

bedrock aquifer in the western and eastern parts of this area.

This water is similar in quality to that in the unconsolidated

sediments.

Soils

The dominant soil orders in this MLRA are Spodosols,

Histosols, and Entisols. The soils in the area have a cryic soil

temperature regime. Most have a udic soil moisture regime and

mixed mineralogy.

Some Humicryods (Partofshikof and Sitka series) on

mountains and hills formed in silty volcanic ash over loamy

and gravelly or cobbly colluvium and glacial till. Other

Humicryods (Tolstoi and Kupreanof series) and Haplocryods

(Remedios series) on mountains and hills formed in colluvium

and glacial till. These Spodosols range from shallow to deep

and from well drained to somewhat poorly drained.

Cryosaprists (Maybeso series), Cryohemists (Kina series), and

Cryofibrists (Staney series) on footslopes, discharge slopes, and

valley floors and in areas directly above timberline formed in

thick deposits of organic material. These soils are generally

deep and are poorly drained or very poorly drained. Cryofolists

(McGilvery series) are on steep mountainsides and are well

drained. Cryaquents (Ashmun series) and Cryofluvents

(Tonowek series) on flood plains, stream terraces, and outwash

plains formed in silty, sandy, and gravelly to cobbly alluvium.

These soils are generally deep and range from well drained to

somewhat poorly drained.

Miscellaneous (nonsoil) areas make up about 23 percent of

this MLRA. The most common miscellaneous areas are chutes,

rock outcrop, rubble land, beaches, riverwash, and water.

Biological Resources

This MLRA consists primarily of the lower elevation

forested and subalpine zones. Western hemlock and Sitka

spruce are the dominant trees on mountains and hills at the

lower elevations. Red cedar and Alaska cedar are more

prevalent in the southern part of the area. Black cottonwood

and mixed forest types occur on flood plains. Areas of peat and

other sites that are too wet for forest growth support sedge-grass

meadows and low scrub. Tall alder scrub is on steep mountain

slopes and in the subalpine zone. Grasslands of bluejoint

reedgrass are common in the subalpine zone. Dwarf alpine

scrub, herbaceous communities, and barren ground dominate

the landscape at elevations of about 2,500 to 3,000 feet (760 to

915 meters) or more.

Some of the major species of mammals in the area are brown

bear, black bear, Sitka black-tailed deer, moose, wolf, and

mountain goat. Many species of migratory waterfowl and shore

birds pass through the area. Extensive coastal meadows in the

Yakutat area are especially important as resting and feeding

sites during migration. Peregrine falcons and bald eagles nest in

the area. Southeast Alaska supports the largest concentration of

bald eagles in the world. The streams and rivers in the area

support healthy populations of wild salmon and freshwater fish.
of the United States 553

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—20%

Forest—57%

Water—2%

Other—21%

For many decades, logging, commercial fishing, and mining

have been the primary enterprises throughout much of the area.

In recent years changes in public interests, land use policies,

and timber economics have contributed to a significant decline

in the timber industry. Commercial fishing continues to be an

important industry, and most communities support a fleet of

boats and fishing-related facilities. A number of mines operate

in the area, and others have been prospected and proposed.

Tourism and wild-land recreation are becoming increasingly

important in the MLRA. During the summer, one or more cruise

ships are likely to be docked in Juneau and other ports in the

area. Flight-seeing, guided fishing, and other recreational tours

are available out of Juneau and other major communities. Less

than 1 percent of the area is urban. Juneau and a number of

smaller communities are experiencing significant growth and

urban development. Subsistence hunting, fishing, and

gathering provide food and a variety of other resources to local

residents and remain the principal economy for the residents of

remote villages.

The major soil resource concerns are water erosion and mass

wasting. Mass wasting induced by earthquakes and erosion can

take the form of creep, earthflow, rockfall, slump, debris

avalanche, and debris flow. Undercutting or overloading slopes,

vibrations from earthquakes, and increased soil moisture

content can trigger mass movements. Mass wasting can be a

natural phenomenon or the result of human activities, such as

logging and road construction.

Conservation practices on forestland generally include

forest stand improvement and properly constructed roads,

landings, and stream crossings. 

Figure 221-1: Location of MLRA 221 in Land Resource Region W1.

221—Kodiak Archipelago

This area is in the Southern Alaska Region (fig. 221-1). It

includes Kodiak Island, Afognak Island, and nearby islands in

the western Gulf of Alaska. It makes up about 5,015 square

miles (12,995 square kilometers). For the most part, the area is

undeveloped wild land and is sparsely populated. The principal

community is the city of Kodiak. A number of small villages are

along the coast. The only roads are in and around the city of

Kodiak and along nearby coastal areas. The Kodiak National

Wildlife Refuge and a small part of the Chugach National

Forest are in this MLRA.

Physiography

This area lies within the Pacific Border Ranges Province of

the Pacific Mountains System. The area is on low to

moderately high, rolling mountains. Broad, nearly level valleys

bordered by low, rolling hills are common at the lower

elevations. The complex, irregular coastline has many

prominent headlands, sea cliffs, and narrow, steep-walled bays.

Elevation ranges from sea level along the coast to 4,405 feet

(1,343 meters) at the summit of Mt. Glottof, near the center of

Kodiak Island.

The only Hydrologic Unit Area (identified by a four-digit

number) that makes up this MLRA is South Central Alaska

(1905). Surface water in the area drains into the Shelikof Strait

and the Pacific Ocean through a number of short rivers and

streams originating in the mountainous uplands. The major

rivers are the Karluk and Uganik Rivers on Kodiak Island. The

largest lakes in the area are Karluk, Frazer, and Red Lakes on

Kodiak Island. Numerous small and medium-size lakes are on

coastal lowlands and the bottoms of broad river valleys. Lakes

make up about 2 percent of the area.

Geology

During the middle to late Pleistocene epoch, all of the

Kodiak Archipelago was covered by glacial ice originating in

the mountains of the Alaska Peninsula and extending 50 to 100

miles (80 to 160 kilometers) or more into the North Pacific. No

glaciers remain today. During the Holocene epoch, colluvium

and slope alluvium accumulated across about 85 percent of the

present-day landscape. Slightly modified glacial moraines and

drift are on hills, in the lower valleys, and on coastal plains.

Most of the present landscape is blanketed by a moderately

thick or thick layer of ash, which originated from volcanoes on

the Alaska Peninsula. The 1912 eruption of Mt. Novarupta

deposited 1 to 2 feet (30 to 60 centimeters) of ash on the

northern half of the islands. Kodiak Island and the adjacent
554 Major Land Resource Areas

islands are underlain mainly by Cretaceous and Lower Tertiary

stratified sedimentary rocks. Older marine sedimentary and

volcanic rocks occur locally. The Trinity Islands and the

southeastern coast of Kodiak Island formed in younger Tertiary

marine and continental rocks. This MLRA is seismically active.

Faults extend across the length of the major islands. Land

subsidence on Kodiak Island, as a result of the 1964 Good

Friday earthquake, has been estimated at 5.4 feet (1.6 meters).

Climate

The average annual precipitation is mostly 23 to 60 inches

(585 to 1,525 millimeters) in the northern half of this area. It is

mostly 60 to 98 inches (1,525 to 2,490 millimeters) on the

Pacific Ocean side. Cloudy conditions, moderate temperatures,

and abundant rainfall characterize the temperate maritime

climate of the area. The average annual snowfall ranges from

about 30 inches (75 centimeters) in the southwestern part of the

area to 100 inches (255 centimeters) in the northeastern part

and at the higher elevations. The average annual temperature

ranges from 40 to 44 degrees F (4 to 7 degrees C). The freezefree period averages 85 to 200 days at the lower elevations but

is much shorter at the highest elevations.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 22.2%; ground water, 44.4%

Livestock—surface water, 0.0%; ground water, 0.0%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 11.1%; ground water, 22.2%

The total withdrawals average about 1 million gallons per

day (3.8 million liters per day). About 67 percent is from

ground water sources, and 33 percent is from surface water

sources. In most years precipitation is adequate for crops, but in

some years yields are reduced by short dry periods in summer.

Permanent streams, originating in the mountainous regions in

the center of the island, carry water to nearly all parts of the

area. The surface water is generally suitable for all uses.

Flooding from ice dams that form during the spring thaw is a

concern in this area.

Unconsolidated sediments along the coast of the island have

some ground water. This water occurs as a lens of freshwater

floating on saltwater. Most of the ground water used in this area

is from the bedrock aquifer. The water is typically similar in

quality to that in the unconsolidated sediments on the island.

Some ground water is obtained from unconsolidated sediments

in the larger river valleys (alluvium) or from buried glacial

outwash deposits in the river valleys or on uplands. This water

is hard or very hard but is otherwise of excellent quality. Wells

in this aquifer generally are shallow, and the aquifer is being

constantly recharged with freshwater (rainfall and runoff). As a

result, the level of total dissolved solids is fairly low unless

seawater has intruded. The median level of total dissolved

solids is about 130 parts per million (milligrams per liter). The

level of iron may exceed the secondary standard for drinking

water of 300 parts per billion (micrograms per liter). The

secondary standard is for esthetics. The iron can stain ceramic

and porcelain and precipitate in pipes. Since this aquifer is

close to the surface and water moves through it quickly, it is

highly susceptible to contamination from runoff. Septic

systems, landfills, and leaking fuel storage tanks are all

possible sources of contamination. The intrusion of seawater

can be a problem along the coast.

Soils

The dominant soil orders in this MLRA are Andisols,

Histosols, and Inceptisols. The soils in the area have a cryic soil

temperature regime, a udic or aquic soil moisture regime, and

dominantly amorphic mineralogy. Haplocryands and

Vitricryands (Kodiak and Pyramid series) on mountain slopes

and hills formed in silty volcanic ash over loamy and gravelly

glacial till or bedrock residuum. These soils range from shallow

to deep and are well drained. Cryaquepts (Ugak and Pasagshak

series) on broad valley bottoms and in glacially scoured

depressions formed in silty volcanic ash over loamy and

gravelly glacial till and colluvium. These soils generally are

deep and somewhat poorly drained. Cryofibrists (Saltery series)

on broad valley bottoms and in depressions formed in thick

deposits of organic material. These soils are somewhat poorly

drained to very poorly drained.

Miscellaneous (nonsoil) areas make up about 18 percent of

this MLRA. The most common miscellaneous areas are rock

outcrop, chutes, rubble land, riverwash, and beaches.

Biological Resources

Sitka spruce forests are dominant at the lower elevations on

uplands in the northeastern part of this area. To the south, the

forests gradually give way to tall alder scrub and grasslands of

bluejoint reedgrass. Flood plains support black cottonwood

and mixed spruce-cottonwood forests, tall and low willow

scrub, tall alder scrub, and various herbaceous plant

communities. At the higher elevations and on Chirikof, Trinity,

and Semidi Islands, the vegetation consists of dwarf scrub and

herbaceous communities.

Some of the major species of mammals in the area are

Kodiak brown bear, Sitka black-tailed deer, Roosevelt elk, and

mountain goat. Many species of waterfowl migrate through the

area or breed or winter in the area. There is a major migration

route through Shelikof Strait and along the Alaska Peninsula.

The coasts provide important wintering habitat for scoters,

eiders, oldsquaws, mallards, and black brant. Other waterfowl in

the area include loons, geese, ducks, and grebes. The rocky

shorelines are excellent habitat for bald eagles and peregrine
of the United States 555

falcons. The area has many major seabird colonies. The streams

and rivers in the area support healthy populations of wild

salmon and freshwater fish.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—68%

Forest—14%

Water—2%

Other—16%

Commercial fishing and fish processing are the primary

enterprises in this area. Most communities support a fleet of

boats and fishing-related facilities. Logging in the northeastern

part of the area provides raw materials for a small-scale wood

products industry. A number of cattle, bison, and game ranches

operate in the area. The meat and other products of these

ranches are consumed locally. Tourism and wild-land recreation

are becoming increasingly important in the area. During the

summer, cruise ships are likely to be docked in the city of

Kodiak. A number of local companies provide opportunities for

flight-seeing, guided fishing and hunting, and a variety of other

recreational activities. The Kodiak Islands are world famous for

the huge Kodiak brown bears that inhabit them. Brown bears

and other local game species attract visitors from around the

world for hunting and wildlife viewing. Subsistence hunting,

fishing, and gathering provide food and a variety of other

resources to local residents and continue to be the principal

economy in many villages. Less than 1 percent of the area is

urban.

The major soil resource concerns are the erodibility of the

soils on steep slopes and slope failures. The slope failures can

be either naturally occurring or accelerated by human activity.

Maintaining a good plant cover on the slopes can minimize

erosion. Conservation practices on the forestland in the

northeastern part of the area generally include forest stand

improvement and properly constructed roads, landings, and

stream crossings. 

Figure 222-1: Location of MLRA 222 in Land Resource Region W1.

222—Southern Alaska Coastal

Mountains

This area is in the Southern Alaska Region (fig. 222-1). It

includes the higher elevations of the Coast, St. Elias, Chugach,

and Kenai Mountains. It makes up about 26,335 square miles

(68,235 square kilometers). The area is almost entirely

undeveloped wild land. Small rural communities along the road

system are the only permanent settlements. Part of the

Wrangell-St. Elias Bay National Park and Preserve, the Glacier

Bay National Park and Preserve, the Misty Fjords National

Monument, the Chugach National Forest, and the Tongass

National Forest are in this area.

Physiography

This area lies within the Coastal Mountains and Pacific

Border Ranges Provinces of the Pacific Mountains System. The

terrain consists of steep, rugged, high-relief mountains; massive

glaciers; and ice fields. Glaciers and ice fields make up about

54 percent of the area. Numerous arêtes and nunataks are

throughout the ice fields. Medial and lateral moraines are

common in the glaciers. Unglaciated areas are deeply incised

with narrow to broad valleys. Flood plains and stream terraces

on valley floors rapidly give rise to steep alluvial fans and

mountain footslopes. Elevation ranges from sea level at the

base of tidewater glaciers and ice fields to 18,008 feet (5,490

meters) at the summit of Mt. St. Elias.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Southeast Alaska (1906), 63 percent, and South Central Alaska

(1905), 37 percent. Surface water in this area drains to the Gulf

of Alaska and North Pacific by way of numerous short, highgradient rivers that originate in the glaciers, ice fields, and

mountainous uplands. Lakes make up less than 1 percent of the

area.

Geology

During the Pleistocene epoch, the area was covered with

glacial ice. Most glacial deposits have eroded away or have

been buried by colluvium and slope alluvium, which covers

more than 90 percent of the present unglaciated landscape. The

remaining glacial and glaciofluvial deposits and recent fluvial

deposits are generally restricted to the bottoms of the larger

valleys. Paleozoic, Mesozoic, and Lower Tertiary stratified
556 Major Land Resource Areas

sedimentary rocks, and occasionally Paleozoic intrusive rocks,

underlie much of the area and are exposed on steep mountain

slopes and ridges.

Climate

The average annual precipitation throughout most of this

area is 120 to 200 inches (3,050 to 5,080 millimeters). It is 250

inches (6,350 millimeters) or more at the highest elevations. It

is 25 to 50 inches (635 to 1,270 millimeters) in small areas

northwest of Juneau, which is just outside this MLRA, and

around and northeast of Copper Center. The precipitation

usually is abundant throughout the year in most of the area.

Cloudy conditions and moderate to cold temperatures

characterize the climate of the area. The average annual

snowfall ranges from about 200 to 800 inches (510 to 2,030

centimeters). It greatly exceeds the annual snowmelt in many

places, as evidenced by the abundance and extent of glaciers

and ice fields. The average annual temperature and length of

the freeze-free period are not known. At the higher elevations,

freezing temperatures are likely to occur during any month of

the year.

Water

There are very limited withdrawals of freshwater for use in

this sparsely populated MLRA. Most of the communities in the

area are along the major rivers. Because of its chemical quality,

the surface water in the area generally is suitable for all uses,

but the rivers either are frozen for much of the year or flow little

during winter. Also, the rivers are typically fed by glacial

meltwater, which carries high loads of suspended sediment. If

surface water is available, treatment for removal of the

suspended sediment would normally be required. For these

reasons, most of the water used for domestic supply in this area

is probably obtained from private wells.

Small communities and rural landowners probably obtain

ground water either from bedrock aquifers or from

unconsolidated sediments in river valleys (alluvium or glacial

outwash). There are seldom any test data available on ground

water in sparsely populated areas. If these aquifers are close to

the surface, they are highly susceptible to contamination from

surface activities. Septic systems, landfills, and leaking fuel

storage tanks are all possible sources of contamination. The

intrusion of seawater can be a problem along the coast.

Soils

The dominant soil orders in this MLRA are Spodosols and

Histosols. The soils in the area have a cryic soil temperature

regime or a subgelic soil temperature class, a udic or aquic soil

moisture regime, and mixed or amorphic mineralogy.

Humicryods (Nanwalek and Tutka series) and Haplocryods on

mountains and hills formed in loamy and gravelly colluvium

and glacial till. These soils range from shallow to deep and

from well drained to somewhat poorly drained. Cryosaprists,

Cryohemists (Koyuktolik and Nuka series), and Cryofibrists on

footslopes, discharge slopes, and valley floors formed in thick

deposits of organic material. These soils generally are deep and

somewhat poorly drained to very poorly drained.

Miscellaneous (nonsoil) areas make up more than 90 percent

of this MLRA. The most common miscellaneous areas are rock

outcrop, rubble land, chutes, and glaciers.

Biological Resources

Most of this MLRA is in the true alpine zone. The

vegetation consists of a variety of dwarf scrub and herbaceous

communities. Low willow scrub is common in drainages.

Lichens, scattered herbs, and dwarf shrubs dominate bedrock

exposures and very shallow soils. In general, there is little or no

plant growth at elevations above about 7,500 feet (2,285

meters). Along the boundary with MLRA 220, there are

stringers and inclusions of tall alder scrub and grasslands of

bluejoint reedgrass, which are characteristic of the subalpine

zone.

Some of the major species of mammals in the area are brown

bear, Dall sheep, mountain goat, moose, wolf, coyote, fox,

snowshoe hare, arctic ground squirrel, and hoary marmot.

Ptarmigan, American golden plovers, golden eagles, and a wide

variety of other birds are common in many places.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—7%

Forest—3%

Other—90%

Remote wild-land recreation is the principal land use in this

area. The rugged, high mountains, extensive glaciers and ice

fields, and wilderness qualities of the area attract visitors from

around the world. Most visitors are served by air taxi, guiding,

and outfitting companies operating out of the major Alaska

communities. Less than 1 percent of this area is urban. There are

no major resource concerns in the area. 

223—Cook Inlet Mountains

This area is in the Southern Alaska Region (fig. 223-1). It

includes the higher mountains of the Aleutian and Alaska

Ranges and the Talkeetna, Kenai, and Chugach Mountains. It

makes up about 19,700 square miles (51,050 square

kilometers). The area is primarily undeveloped wild land and is
of the United States 557

Figure 223-1: Location of MLRA 223 in Land Resource Region W1.

sparsely populated. A number of small communities, the largest

of which is Cantwell, are along the road system. Parts of Denali

National Park and Preserve, Lake Clark National Park and

Preserve, Kenai National Wildlife Refuge, and Chugach

National Forest are in this area.

Physiography

The part of this area in the Alaska and Aleutian Ranges lies

within the Alaska-Aleutian Province. The part in the Kenai and

Chugach Mountains lies within the Pacific Border Ranges

Province. The part in the Talkeetna Mountains lies within the

Coastal Trough Province. All of these provinces are within the

Pacific Mountains System. The terrain throughout the area

consists primarily of rugged, moderate to high mountains.

Massive valley glaciers and ice fields are prominent at the

higher elevations. Many of the larger valley glaciers extend

down to an elevation of about 1,000 feet (305 meters) and into

the upper edge of the Cook Inlet Lowlands. Glaciers and ice

fields make up about 15 percent of the area. The mountains

throughout the area are deeply incised with narrow to broad

valleys that have braided, high-gradient flood plains.

Coalescing alluvial fans and long footslopes are common on

the lower mountain slopes in broad valleys. Elevation

generally ranges from about 2,500 feet (760 meters) along the

boundary with the Cook Inlet Lowlands to 20,320 feet (6,195

meters) at the summit of Mt. McKinley, the highest point in

North America. Also, the elevation extends down to sea level in

small areas along the Turnagain Arm of Cook Inlet.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

South Central Alaska (1905), 97 percent; Southwest Alaska

(1904), 2 percent; and Yukon (1903), 1 percent. All of the rivers

in the area drain into the Cook Inlet Lowlands and Cook Inlet.

The Matanuska, Little Susitna, Knik, Kenai, and Chakachatna

Rivers and major tributaries of the Susitna River, including the

Yentna, Skwenta, Chulitna, Talkeetna, and Kashwitna Rivers,

originate in glaciers and mountainous uplands in the area. The

largest lakes are Chakachamna and Chelatna Lakes in the

Alaska Range and Eklutna and Kenai Lakes in the Chugach

Mountains. Lakes make up about 2 percent of the area.

Geology

The entire area, except for the highest peaks and the steep

upper ridges, was covered by glacial ice during the late

Pleistocene epoch. Most of the glacial deposits have eroded

away or were buried by colluvium and slope alluvium during

the Holocene epoch. Colluvial and alluvial deposits cover

about 65 percent of the present landscape. Slightly modified to

highly modified glacial moraines and outwash deposits are

extensive on the lower mountain slopes and in valleys at the

lower elevations. Holocene eolian deposits, consisting of an

admixture of loess and volcanic ash and ranging in thickness

from a few inches to 24 inches (60 centimeters) or more, have

accumulated on the mid and lower mountain slopes. Valley

bottoms are buried with recent fluvial deposits. The bedrock

geology consists primarily of late Paleozoic and early

Mesozoic stratified sedimentary rocks. Tertiary intrusive rocks

are common.

Climate

The average annual precipitation in this area ranges from

about 15 to 30 inches (380 to 760 millimeters) along the

boundary with the Cook Inlet Lowlands (MLRA 224) to more

than 100 inches (2,540 millimeters) in the highest mountains.

Later summer and fall are generally the rainiest periods. Cloudy

conditions, short summers, and moderate to cold temperatures

characterize the climate of the area. The average annual

snowfall ranges from about 80 to 400 inches (205 to 1,015

centimeters) or more. The average annual temperature at

Puntilla Lake in the Alaska Range is 27 degrees F (-3 degrees

C). The freeze-free period averages about 60 to 80 days. At the

higher elevations, freezing temperatures can occur during every

month.

Water

There are very limited withdrawals of freshwater for use in

this sparsely populated MLRA. Most of the communities in the

area are along the major rivers. Because of its chemical quality,

the surface water in the area generally is suitable for all uses,

but the rivers are frozen for much of the year or flow little

during winter. Also, the rivers are typically fed by glacial

meltwater, which carries a high load of suspended sediment. If

surface water is available, treatment for removal of the

suspended sediment would normally be required. For these
558 Major Land Resource Areas

reasons, most of the water used for domestic supply in this area

is probably obtained from private wells.

Small communities and rural landowners probably obtain

ground water either from bedrock aquifers or from

unconsolidated sediments in river valleys (alluvium or glacial

outwash). There are seldom any test data available on ground

water in sparsely populated areas. If these aquifers are close to

the surface, they are highly susceptible to contamination from

surface activities. Septic systems, landfills, and leaking fuel

storage tanks are all possible sources of contamination. The

intrusion of seawater can be a problem along the coast.

Soils

The dominant soil orders in this MLRA are Spodosols,

Inceptisols, Gelisols, and Entisols. The soils in the area have a

cryic soil temperature regime or a subgelic soil temperature

class, a udic or aquic soil moisture regime, and amorphic or

mixed mineralogy. Eutrocryepts and Dystrocryepts on strongly

sloping to steep slopes formed in gravelly colluvium over

fractured bedrock of varied lithology. They range from shallow

to very deep and generally are well drained. Histoturbels and

Aquiturbels are on landforms similar to those of the

Eutrocryepts and Dystrocryepts but have finer textures and are

poorly drained. Haplocryods, Humicryods, and Cryaquods on

mid-mountain slopes formed in a surface layer of silty loess and

volcanic ash over gravelly glacial drift or colluvium. These

soils are generally deep and range from well drained to poorly

drained. Cryofluvents, Cryorthents, and Cryaquents on flood

plains formed in loamy and gravelly alluvium. They generally

are deep and range from very poorly drained to excessively

drained.

Miscellaneous (nonsoil) areas make up about 70 percent of

this MLRA. The most common miscellaneous areas are rock

outcrop, rubble land, and glaciers.

Biological Resources

For the most part, this MLRA includes only the true alpine

zone. The vegetation consists of a variety of dwarf scrub and

herbaceous communities. Low willow scrub is common in

drainages. Lichens and scattered herbs and dwarf shrubs

dominate bedrock exposures and very shallow soils. In general,

there is little or no plant growth at elevations above about

7,500 feet (2,285 meters). Along the boundary with the Cook

Inlet Lowlands, there are stringers and inclusions of tall alder

scrub and grasslands of bluejoint reedgrass, which are

characteristic of the subalpine zone.

Some of the major species of mammals in the area are

brown bear, Dall sheep, mountain goat, caribou, moose, wolf,

coyote, fox, snowshoe hare, arctic ground squirrel, and hoary

marmot. Ptarmigan, American golden plovers, golden

eagles, and a wide variety of other birds are common in many

places.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—22%

Forest—8%

Water—2%

Other—68%

Remote wild-land recreation is the principal land use in this

area. The rugged mountains, extensive glaciers, ice fields, and

wilderness qualities of the area attract hikers and wilderness

enthusiasts from around the world. Every summer, hundreds of

climbers attempt to climb Mt. McKinley and other high peaks

in the area. More people visit Denali National Park than any

other park in Alaska. Hunters pursue moose, caribou, Dall

sheep, brown bear, and black bear. Back-country recreationists

and hunters are served by air taxi, guiding, and outfitting

companies operating out of the major Alaska communities.

Many extractable minerals and other commodities occur in this

MLRA. Mining was historically a major land use that helped to

support development on nearby lowlands. Less than 1 percent

of this area is urban. There are no major resource concerns in

the area. 

224—Cook Inlet Lowlands

This area is in the Southern Alaska Region (fig. 224-1). It

includes the lowlands and lower mountain slopes of the Susitna

and Matanuska Valleys, the western Kenai Peninsula, and the

west side of Cook Inlet. It makes up about 10,635 square miles

(27,565 square kilometers). It includes the most densely

populated areas of Alaska and has the most extensive network

of highways and secondary roads in the State. It includes the

municipality of Anchorage, the cities of Palmer and Wasilla in

the lower Matanuska Valley, and the cities of Kenai and

Soldotna on the western Kenai Peninsula. Most of the Kenai

National Wildlife Refuge and parts of the Chugach National

Forest and Denali National Park and Preserve are in this area.

Physiography

This area lies within the Coastal Trough Province of the

Pacific Mountains System. The terrain is dominantly a broad

expanse of gently sloping to rolling plains and low- or

moderate-relief hills bordered by the lower slopes of the

surrounding mountains. Depressions and shallow basins on

plains are dotted with thousands of small and medium-size
of the United States 559

Figure 224-1: Location of MLRA 224 in Land Resource Region W1.

lakes and interconnecting wetlands. Lakes also are common in

low areas between hills. Rivers have relatively high gradients,

and braided flood plains and low to high stream terraces are

common along the rivers. The area includes the Caribou Hills,

Mt. Susitna, Beluga Mountain, and the Yenlo Hills. These are

isolated, low to moderately high, rounded mountains that

protrude above the surrounding terrain. Coalescing alluvial

fans are common on the lower mountain slopes. Elevation

ranges from sea level to 4,396 feet (0 to 1,340 meters).

The only Hydrologic Unit Area (identified by a four-digit

number) that makes up this MLRA is South Central Alaska

(1905). Numerous rivers, which originate in the surrounding

Cook Inlet Mountains (MLRA 223), pass through the area. All

of the rivers and streams drain into Cook Inlet. The major rivers

are the Susitna and Yentna Rivers in the Susitna Valley, the

Little Susitna River and Matanuska River in the Matanuska

Valley, and the Kenai River and Deep Creek on the Kenai

Peninsula. Other important rivers or tributaries include the

Kustatan River on the west side of Cook Inlet, Ship Creek and

Eagle River in the municipality of Anchorage, and Willow

Creek, Montana Creek, Lake Creek, and the Deshka River in

the Susitna Valley. The largest lakes are Tustumena Lake and

Skilak Lake on the Kenai Peninsula and Beluga Lake on the

west side of Cook Inlet. Small and medium-size lakes are in

scattered areas throughout the rolling plains and hills in the

Susitna Valley, the western Matanuska Valley, and the northern

Kenai Peninsula. Lakes and other areas of surface water make

up about 15 percent of the MLRA.

Geology

The area has a complex history of repeated glaciation.

During the late Pleistocene epoch, the entire area was covered

by glacial ice originating from the surrounding mountains. At

times during the early and middle Pleistocene, ice dams at the

lower end of Cook Inlet caused much of the area to be covered

with a large proglacial lake. Surficial deposits on plains and

hills consist of a complex mixture of glacial till and outwash.

Fine textured glaciolacustrine deposits and sand dunes are in a

few areas, primarily near the coast in the southern Susitna

Valley, in the municipality of Anchorage, and on the western

Kenai Peninsula. Recent fluvial deposits cover modern flood

plains and stream terraces. During the Holocene epoch, winds

blowing sediments from unvegetated flood plains and volcanic

activity in the Alaska and Aleutian Ranges deposited a layer of

mixed loess and volcanic ash across much of the area. In the

vicinity of the city of Palmer, along the lower Matanuska and

Knik Rivers, the layer of loess is many meters thick.

Climate

The average annual precipitation in this area ranges from 15

to 60 inches (380 to 1,525 millimeters). It generally is higher

on the southern Kenai Peninsula, in the northern Susitna Valley,

and at the higher elevations along the mountains. The average

annual snowfall is about 60 to 120 inches (150 to 305

centimeters). The climate of this area is considered to be

transitional from temperate maritime to subarctic continental.

Most weather systems originate in the North Pacific and the

Gulf of Alaska. In winter, particularly in the northern part of the

area, arctic weather systems are more common. In the

Matanuska Valley, seasonal winds pick up fine-earth material

from unvegetated flood plains and create extensive dust clouds

that can reach an altitude of 5,000 feet (1,525 meters) or more.

The average annual temperature is about 27 to 36 degrees F

(-3 to 2 degrees C). The freeze-free period averages 65 to 160

days, decreasing in length with elevation.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 24.8%; ground water, 12.1%

Livestock—surface water, 0.1%; ground water, 0.1%

Irrigation—surface water, 0.1%; ground water, 0.0%

Other—surface water, 56.3%; ground water, 6.6%

The total withdrawals average 175 million gallons per day

(660 million liters per day). About 19 percent is from ground

water sources, and 81 percent is from surface water sources. In

most years precipitation is adequate for crops, but in some years

yields are reduced by short dry periods in summer. Permanent

streams carry water to nearly all parts of the area. Some outlets

for natural lakes in this area have been dammed. The stored

water is used for limited irrigation, public supply, and the needs

of seafood-processing plants. Anchorage obtains supplemental

surface water for public supply in developing areas from a

pipeline from Lake Eklutna. The surface water generally is

suitable for all uses. Rivers fed by glacial meltwater typically

carry high loads of suspended sediment, and water in the lakes

can require treatment. Flooding from ice dams that form during

the spring thaw is a concern in this area.
560 Major Land Resource Areas

Ground water is used for public supply and for the needs of

seafood processing and a large petrochemical industrial

complex on the Kenai Peninsula. It is pumped primarily from

the Anchorage, Matanuska-Susitna, and Kenai Peninsula

aquifers. These aquifers are either unconsolidated sediments in

river valleys (alluvium) or buried glacial outwash deposits in

river valleys or on uplands. This water is hard or very hard but

is otherwise of excellent quality. Wells in these aquifers

generally are shallow, and the aquifers are being constantly

recharged with freshwater (rainfall and runoff). As a result, the

median level of total dissolved solids is fairly low, ranging from

150 to 200 parts per million (milligrams per liter). The median

level of iron approaches 2,000 parts per billion (micrograms per

liter) in the Anchorage aquifer. The level of iron may exceed the

secondary standard for drinking water of 300 parts per billion

(micrograms per liter) in the Kenai Peninsula aquifer but not in

the Matanuska-Susitna aquifer. The secondary standard for iron

is for esthetics. The iron can stain ceramic and porcelain and

precipitate in pipes. Since the aquifers are close to the surface

and water moves through them quickly, they are highly

susceptible to contamination from runoff. Septic systems,

landfills, and leaking fuel storage tanks are all possible sources

of contamination. The intrusion of seawater can be a problem

along Cook Inlet.

Small amounts of ground water can be obtained from the

bedrock aquifer in the higher parts of this area. This water is

typically similar in quality to that in the unconsolidated

sediments.

Soils

The dominant soil orders in this MLRA are Spodosols,

Histosols, Entisols, and Inceptisols. The soils in the area have a

cryic soil temperature regime, a udic or aquic soil moisture

regime, and dominantly mixed mineralogy. Haplocryods

(Estelle and Kenai series), Humicryods (Talkeetna series),

Eutrocryepts (Bodenburg series), and Dystrocryepts (Smithfha

series) on plains and hills formed in silty loess and volcanic ash

over loamy, sandy, and gravelly glacial till and outwash. These

soils generally are deep and well drained. Cryaquepts (Slikok

and Disappear series) on plains and hills also formed in silty

loess and volcanic ash over loamy, sandy, and gravelly glacial

till and outwash. They are poorly drained or very poorly

drained. Cryofibrists (Salamatof series) and Cryohemists

(Starichkof series) in broad shallow basins and drainageways

formed in thick deposits of organic material. These Histosols

are poorly drained or very poorly drained. Cryofluvents

(Niklason series) and Cryaquents (Killey series) on flood plains

and stream terraces formed in stratified silty and sandy

alluvium over gravelly alluvium. They generally are deep and

range from well drained to very poorly drained.

Miscellaneous (nonsoil) areas make up about 15 percent of

this MLRA. The most common miscellaneous areas are

beaches, riverwash, and water.

Biological Resources

This MLRA primarily includes the lower lying forested and

subalpine zones. The vegetation on upland sites is dominated

by white spruce, paper birch, and quaking aspen. Lutz spruce is

dominant on the southern Kenai Peninsula. On flood plains and

in seepage areas on mountain slopes, cottonwood and mixed

cottonwood forests are common. Extensive lowlands and areas

of peat support stunted white and black spruce, low scrub of

ericaceous shrubs and willow, and a variety of sedge and grass

meadows. Halophytic sedge and sedge-grass meadows are

along the coast of Cook Inlet. At the higher elevations in the

subalpine zone, forest gradually gives way to grasslands of

bluejoint reedgrass, tall alder scrub, and low willow scrub.

Dwarf scrub and herbaceous communities characteristic of the

alpine zone are above elevations of about 1,800 to 2,500 feet

(550 to 760 meters) in the Caribou Hills on the southern Kenai

Peninsula, on Mt. Susitna and the Yenlo Hills in the Susitna

Valley, and along the boundary with the Cook Inlet Mountains

(MLRA 223).

Since the mid 1980s, spruce bark beetles have infested tens

of thousands of acres of white spruce, Lutz spruce, and mixed

spruce forests on the Kenai Peninsula, in the southern

Matanuska and Susitna Valleys, and along the west side of

Cook Inlet. Across this area, and in particular on the Kenai

Peninsula, the vast majority of large-diameter spruce trees have

been killed by bark beetles. On the southern Kenai Peninsula,

the dominant forest canopy has been entirely killed off by the

bark beetles.

Some of the major species of mammals in the area are moose,

brown bear, black bear, wolf, coyote, fox, beaver, and lynx.

Caribou are common in a few places. Tundra swans, Canada

geese, a wide variety of ducks, and sandhill cranes use the

wetlands and lakes in the area for nesting and as stop-over sites

during migration. Spruce grouse are common throughout the

forests. Throughout much of the year, bald eagles are evident

along rivers and streams.

Most of the rivers and streams in the area are important

spawning grounds for salmon. Thousands of visitors are

attracted to the area each year for sport fishing for Chinook,

coho, and red salmon. Rivers on the Kenai Peninsula support

anadromous steelhead fisheries. Rainbow trout are in many

streams and lakes. The Alaska Department of Fish and Game

stocks many lakes throughout the area with rainbow trout.

Introduced northern pike are in most of the lakes in the

Susitna Valley. They are a major predator of small fish and

waterfowl.
of the United States 561

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—1%

Grassland—24%

Forest—59%

Urban development—1%

Water—15%

Agriculture has been important in this area since the

beginning of European settlement and particularly since 1935,

when the Matanuska Colony was established near the city of

Palmer. Other agricultural areas in the MLRA are in the Susitna

Valley, at Point Mackenzie, and around the cities of Sterling,

Soldotna, and Homer on the Kenai Peninsula. The principal

crops grown in the area are hay, potatoes, and other hardy

vegetables. A few dairy farms are still operating in the Palmer

area, at Point Mackenzie, and on the Kenai Peninsula. Cattle

graze native rangeland and pasture on the southern Kenai

Peninsula. Logging and personal-use firewood cutting are

locally significant. In response to the bark beetle infestation,

salvage logging and other management activities on the Kenai

Peninsula have resulted in the construction of hundreds of

miles of roads and in clear-cut logging on thousands of acres.

The other major industries in the area include commercial

fishing, fish processing, and oil and gas extraction.

Tourism and wild-land recreation are becoming increasingly

important in the area. The recreation and tourism industries

include hunting, fishing, back-country guiding, bus tours, and

flight-seeing. Many local residents participate in hunting for

moose and other game and fishing for salmon, halibut, trout,

and northern pike. In winter, snowmobile trails crisscross the

Susitna Valley. Extensive ATV trails provide summer and fall

access to much of the area. Recreational cabins have been

constructed beside many lakes and in other areas. Subsistence

hunting, fishing, and gathering provide food and a variety of

other resources for many residents.

Urban development, particularly along the road system, is

a significant land use. Most of the land available for

development within the municipality of Anchorage has

already been developed. Rapid urbanization is occurring in

the vicinity of Palmer and Wasilla in the lower Matanuska

Valley and in the cities of Kenai and Soldotna on the Kenai

Peninsula. In all parts of the area, agricultural lands are being

converted to residential and small industrial developments.

Extraction of sand and gravel in support of construction, road

building, and road maintenance impacts thousands of acres in

the lower Matanuska Valley and in other locations along the

road system.

The major resource concerns are water erosion and water

quality. Off-road vehicle use is an increasing problem

Figure 225-1: Location of MLRA 225 in Land Resource Region W1.

225—Southern Alaska Peninsula

Mountains

This area is in the Southern Alaska Region (fig. 225-1). It

includes the southeast-facing slopes of the southern Aleutian

Mountains, where drainage is into the lower Cook Inlet,

Shelikof Strait, and the North Pacific. The area makes up about

6,090 square miles (15,780 square kilometers). It is mostly

undeveloped wild land. The only permanent settlements in the

area are a few small coastal villages. The Becharof National

Wildlife Refuge and parts of the Alaska Maritime Wildlife

Refuge, Alaska Peninsula Wildlife Refuge, Lake Clark National

Park and Preserve, and Katmai National Park and Preserve are in

this area.

Physiography

This area lies within the Alaska-Aleutian Province of the

Pacific Mountains System. The terrain consists primarily of

throughout much of the MLRA, contributing locally to the

destruction of the existing vegetation and causing surface

compaction, erosion (sheet and rill, concentrated flow, and

gully), damage to stream channels and fisheries, and changes in

access and land use. Conservation practices that minimize

ground disturbance and maintain an adequate plant cover are

needed. Conservation practices on forestland generally include

forest stand improvement; proper construction of roads,

landings, and stream crossings; and road closures. Critical-area

stabilization is important in many areas disturbed or damaged

by off-road vehicles. 
562 Major Land Resource Areas

rugged, low to moderately high mountains deeply dissected

with narrow, high-gradient valleys. Glaciers and small ice fields

are common at the upper elevations on the highest peaks in the

area. Glaciers and permanent ice and snow make up about 7

percent of the area. In steep, narrow valleys, coalescing fans and

steep footslopes continue down to the stream channel. Flood

plains and stream terraces are of limited extent, except

in the broader valleys at the lower elevations. A narrow,

discontinuous zone of gently sloping to moderately steep

outwash plains, flood plains, and low-relief hills is along the

coast of Cook Inlet. Elevation ranges from sea level along

the coast to 7,090 feet (2,160 meters) at the summit of Snowy

Peak.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

South Central Alaska (1905), 87 percent, and Southwest Alaska

(1904), 13 percent. All of the rivers and streams in the area

originate in glaciers, ice fields, and mountainous uplands and

drain directly into Cook Inlet. Lakes make up less than 2

percent of the area.

Geology

Except for the highest peaks and steep upper ridges, the

entire area was covered with glacial ice during the late

Pleistocene epoch. During the Holocene epoch, glacial deposits

across much of the area eroded away or were buried by

mountain colluvium and alluvium, which cover about 60

percent of the present landscape. Slightly modified to highly

modified glacial moraines and outwash deposits and recent

alluvium are extensive on the lower mountain slopes and in

valleys at the lower elevations. Volcanic activity in Mt. Katmai

and other volcanoes in the area has deposited a layer of

volcanic ash across much of the landscape. The dominant

geologic formations underlying most of the area are upper

Jurassic, lower Tertiary, and some Cretaceous stratified

sedimentary rocks. Undifferentiated volcanic rocks of

Quaternary and Tertiary age are common near Mt. Katmai and

other volcanoes.

Climate

The average annual precipitation in most of this area is 60 to

90 inches (1,525 to 2,285 millimeters). It ranges from about 30

inches (760 millimeters) in spots along the coast to more than

100 inches (2,540 millimeters) at the higher elevations. The

precipitation is usually abundant throughout the year. Cloudy

conditions and moderate to cold temperatures characterize the

climate of the area. The average annual snowfall is about 50 to

200 inches (125 to 510 centimeters). It greatly exceeds annual

snowmelt in many places, as evidenced by the abundance of

glaciers and ice fields. The average annual temperature and

length of the freeze-free period are not known. Freezing

temperatures are likely to occur during any month of the year,

particularly at the higher elevations.

Water

There are very limited withdrawals of freshwater for use in

this sparsely populated MLRA. Most of the communities in the

area are along the major rivers. Because of its chemical quality,

the surface water in the area generally is suitable for all uses,

but the rivers are frozen for much of the year or flow little

during winter. Also, the rivers are typically fed by glacial

meltwater, which carries high loads of suspended sediment. If

surface water is available, treatment for removal of the

suspended sediment would normally be required. For these

reasons, most of the water used for domestic purposes in this

area is probably obtained from private wells.

Small communities and rural landowners probably obtain

ground water either from bedrock aquifers or from

unconsolidated sediments in river valleys (alluvium or glacial

outwash). There are seldom any test data available on ground

water in sparsely populated areas. If these aquifers are close to

the surface, they are highly susceptible to contamination from

surface activities. Septic systems, landfills, and leaking fuel

storage tanks are all possible sources of contamination. The

intrusion of seawater can be a problem along the coast.

Soils

The dominant soil orders in this MLRA are Andisols,

Histosols, and Inceptisols. The soils in the area have a cryic soil

temperature regime or a subgelic soil temperature class, a udic

or aquic soil moisture regime, and dominantly amorphic

mineralogy. Haplocryands and Dystrocryepts on mountain

slopes and hills formed in a layer of silty volcanic ash of

varying thickness over gravelly and loamy colluvium, slope

alluvium, and glacial till. These soils range from shallow to

deep and generally are well drained. Cryaquepts on valley

bottoms, in depressions, and on benches on mountains formed

in silty volcanic ash over loamy glacial till and colluvium.

They generally are deep and somewhat poorly drained.

Cryofibrists on valley bottoms and in depressions formed in

thick deposits of organic material. They are poorly drained or

very poorly drained.

Miscellaneous (nonsoil) areas make up about 51 percent of

this MLRA. The most common miscellaneous areas are rock

outcrop, rubble land, glaciers, riverwash, and beaches.

Biological Resources

At the lower elevations, the vegetation is mostly tall scrub

dominated by alder and willow. Balsam poplar forests, with tall
of the United States 563

shrub and herbaceous understory, are on flood plains and on

some south-facing mountain slopes. With increasing elevation,

tall scrub rapidly gives way to low scrub dominated by willow,

ericaceous shrubs, and various graminoids and forbs. Scattered

grasslands of bluejoint reedgrass are throughout the scrub.

Dwarf scrub is the dominant vegetation at the highest

elevations and on exposed ridges and steep slopes where the

soils are shallow over bedrock. Crowberry, ericaceous shrubs,

willow, bryophytes, and lichens generally dominate dwarf

shrub communities. Poorly drained areas and areas of peat

support low scrub and sedge-grass meadows.

Some of the major species of mammals in the area are brown

bear, Dall sheep, moose, wolf, and coyote. Ptarmigan, American

golden plovers, golden eagles, and a wide variety of other birds

are common in many places.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—47%

Forest—2%

Water—2%

Other—49%

Remote wild-land recreation is the principal land use in this

area. The rugged mountains, extensive glaciers and ice fields,

and wilderness qualities of the area attract visitors from around

the world. Most visitors are served by air taxi, guiding, and

outfitting companies operating out of the major Alaskan

communities. There are no major resource concerns in this

area. 

565

Figure W2-1: Location of Land Resource Region W2.

W2—Aleutian Alaska

This region includes the southwest part of the Alaska

Peninsula, the Aleutian Islands, and the Pribilof Islands (fig.

W2-1). It makes up 10,670 square miles (27,645 square

kilometers).

This region is made up of volcanoes (many of which are

active), lava flows, and tilted fault blocks of volcanic-derived

sediments. Landforms include steep mountain slopes, rolling

hills, and steep-walled fjords and sea cliffs (fig. W2-2). The

eastern part of the region has been glaciated. Elevation ranges

from sea level to more than 4,000 feet (0 to 1,220 meters). The

region is free of permafrost. Cool temperatures, strong winds,

fog, overcast skies, and precipitation characterize the maritime

climate of the region. The annual precipitation ranges from

about 21 to more than 78 inches (535 to 1,980 millimeters).

The average annual air temperature ranges from 36 to 39

degrees F (2 to 4 degrees C). The freeze-free period averages

about 115 to 140 days. It typically occurs from May to midSeptember.

The total withdrawals of freshwater in this region average

about 1.3 million gallons per day (5 million liters per day).

About 46 percent is from surface water sources, and 54 percent

is from ground water sources. Almost 70 percent of the water is

used for the needs of the seafood industry. The rest is used as

public supply or livestock water.

The dominant soils are Andisols, primarily Cryands that

formed in volcanic ash or scoria. The soils in the area have a

cryic soil temperature regime, a udic or aquic soil moisture

regime, and amorphic or mixed mineralogy. Soil texture

grades from coarse scoria and cinders to fine sand with

increasing distance from the volcanoes. Bare rock and rubble

occur on the steep slopes of volcanic cones, peaks, and high

ridges. Histosols, especially Fibrists, occur in depressions and

on broad valley bottoms.

This region supports no trees. Dwarf scrub vegetation occurs

at the higher elevations and in areas exposed to strong winds.

The more protected areas support mesic graminoid herbaceous

vegetation. The major land uses in the region are wildlife
566 Major Land Resource Areas

Figure W2-2: Recent volcanic deposits in an area of Land Resource Region W2.

habitat and subsistence hunting, fishing, and gathering. Small

communities with fishing operations are located in the few

good harbors. A few areas are used for recreation or some

livestock grazing. 
of the United States 567

Figure 226-1: Location of MLRA 226 in Land Resource Region W2.

226—Aleutian Islands-Western Alaska

Peninsula

This area is the only MLRA in the Aleutian Alaska Region

(fig. 226-1). It includes the Aleutian Islands, the Pribilof

Islands, and the southwest end of the Alaska Peninsula west of

Port Moeller, Stepovak Bay, and Shumagin Island. It makes up

about 10,670 square miles (27,645 square kilometers). The area

is remote and consists primarily of undeveloped wild land, but

a number of major towns, small villages, and military

installations are across the area. The largest communities are

Cold Bay, Unalaska, Dutch Harbor, and St. Paul. The Aniakchak

National Monument and Preserve, the Izembek National

Wildlife Refuge, and parts of the Alaska Maritime and Alaska

Peninsula National Wildlife Refuges are in this area.

Physiography

This area lies within the Alaska-Aleutian Province of the

Pacific Mountains System. It is dominantly on steep, low to

moderately high, rounded mountains and isolated, moderately

high volcanic cones. At the lower elevations on the larger

islands and on the Alaska Peninsula, broad, moderately sloping

valleys and rolling uplands bordered by low-relief hills are

common. Valley features include gently sloping fans; narrow,

meandering flood plains; and shallow basins dotted with small

lakes and interconnecting wetlands. The complex, irregular

coastline has many prominent headlands, sea cliffs, and narrow,

steep-walled bays. Elevation ranges from sea level to more than

4,000 feet (1,220 meters) on many of the islands. The highest

point in the Aleutian Islands is 9,372 feet (2,857 meters) at the

summit of Shishaldin Volcano on Unimak Island.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Southwest Alaska (1904), 99 percent, and South Central Alaska

(1905), 1 percent. Surface water in this area is drained into the

North Pacific and the Bering Sea by numerous short, steepgradient rivers and streams. Lakes make up less than 2 percent

of the area.

Geology

This MLRA includes more than 50 volcanoes, most of which

were active at some time during the Quaternary and Tertiary

periods. The area is made up primarily of Quaternary and

Tertiary volcanic rocks and unconsolidated deposits overlying

a mostly submarine ridge of Tertiary sedimentary rocks. During

the Pleistocene epoch, glacial ice covered the eastern part of

the area to approximately Umnak Island. To the west, probably

only the upper elevations were glaciated. Volcanic activity has

mantled most of the area with thick deposits of silty volcanic

ash, sandy and gravelly cinders, and volcanic rubble. Some

slightly modified or moderately modified glacial landforms and

deposits are at the lower elevations. Glaciers make up only

about 1.5 percent of the present landscape and are restricted to

the upper elevations of the highest volcanoes. Recent coastal

and fluvial deposits occur in scattered areas along the coast and

on flood plains at the lower elevations.

Climate

The average annual precipitation in this area ranges from 21

to about 78 inches (535 to 1,980 millimeters), generally

increasing with elevation. The area has a cool maritime climate

characterized by cloudy and foggy conditions, moderate

temperatures, and abundant rainfall. Gale-force winds,

occasionally approaching 100 miles per hour (160 kilometers

per hour), are common during storms. The annual snowfall is 30

to 85 inches (75 to 215 centimeters) at the higher elevations.

The average annual temperature is 36 to 39 degrees F (2 to 4

degrees C). The freeze-free period averages about 115 to 140

days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 7.7%; ground water, 15.4%

Livestock—surface water, 7.7%; ground water, 0.0%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 30.8%; ground water, 38.5%

The total withdrawals average 1.3 million gallons per day

(5 million liters per day). About 54 percent is from ground water

sources, and 46 percent is from surface water sources.

In most years precipitation is adequate for crops in parts of

this area, but in some years yields are reduced by short dry

periods in summer. Some permanent streams, originating in

the mountainous regions on the islands and the Alaska

Peninsula, carry water to many parts of the area. The
568

surface water generally is suitable for all uses. The rivers fed by

glacial meltwater typically carry high loads of suspended

sediment.

The ground water used in this area is primarily from

unconsolidated sediments in river valleys (alluvium or glacial

outwash), but some is from bedrock aquifers. A significant area

is underlain by the unconsolidated sediment aquifer on the

northern side of the part of this MLRA on the Alaska Peninsula.

This aquifer may also occur in the valleys along some of the

larger streams. The ground water occurs as a lens of freshwater

floating on saltwater near the coast. There are very little waterquality test data from either aquifer in this area. The results of

tests in other areas indicate that the ground water is probably

hard or very hard but otherwise is of excellent quality. Wells

generally are shallow in the unconsolidated sediment aquifer,

and this aquifer is being constantly recharged with freshwater

(rainfall and runoff). As a result, the level of total dissolved

solids is fairly low unless some intrusion of seawater has

occurred. The level of iron may exceed the secondary standard

for drinking water of 300 parts per billion (micrograms per

liter). The secondary standard is for esthetics. The iron can stain

ceramic and porcelain and precipitate in pipes. The water in the

bedrock aquifer generally is very similar in quality to the water

in the unconsolidated sediments. Shallow aquifers are highly

susceptible to contamination from runoff. Septic systems,

landfills, and leaking fuel storage tanks are all possible sources

of contamination. The intrusion of seawater can be a problem

along the coast.

Soils

The dominant soil orders in this MLRA are Andisols and

Histosols. The soils in the area have a cryic soil temperature

regime, a udic or aquic soil moisture regime, and amorphic or

mixed mineralogy. Haplocryands (Zolotoi series) and

Vitricryands (Polovina series), the dominant soils on most

landforms, formed in moderately thick or thick deposits of silty

to sandy volcanic ash and coarse sandy to gravelly cinders over

basalt bedrock. These soils range from shallow to deep and

generally are well drained to excessively drained. Andic,

Vitrandic (Tsammana series), and Aquandic subgroups of

Dystrocryepts occur where coarse marine sediments underlie

volcanic deposits. Along the margins of streams and lakeshores,

poorly drained or very poorly drained Cryofibrists formed in

thick deposits of organic material.

Miscellaneous (nonsoil) areas make up about 46 percent of

this MLRA. The most common miscellaneous areas are cinder

land, rock outcrop, water, riverwash, and beaches. Small valley

glaciers are at the upper elevations on a few of the larger islands

and on the Alaska Peninsula.

Biological Resources

At the higher elevations in this area, the vegetation consists

of a mosaic of dwarf shrub scrub characteristic of the true alpine

zone. At the lower elevations, wet and dry grasslands are

dominated by mid-sized and tall grasses, sedges, and forbs. In

areas of peat, the vegetation consists of low ericaceous shrub

scrub. Aleutian shield-fern, the only endangered plant species

currently listed for Alaska, is on Adak and Attu Islands. There

are no naturally occurring forests in the area.

This MLRA is rich in marine and bird wildlife. Two species

native to the Aleutian Islands, the Steller sea lion and the

Aleutian Canada goose, are currently listed as threatened. The

area is an important winter habitat for emperor geese and other

waterfowl. It provides nesting habitat for a variety of birds,

including green-winged teal, rock sandpiper, whiskered auklet,

rock ptarmigan, song sparrow, rosy finch, and winter wren. The

introduction of dogs, cats, and foxes has severely reduced the

population of ground-nesting birds. Rats escaping from ships

also are a hazard to these birds. Northern fur seals, Steller sea

lions, and sea otters are common along the coast. Pink salmon

and sockeye salmon are the most numerous fish species in the

Aleutian Islands. Some of the eastern islands support small

herds of caribou.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—54%

Water—2%

Other—44%

Commercial fishing in the North Pacific and Bering Sea is

the primary enterprise in this area. Most of the communities in

the area support a fleet of boats and related fishing facilities.

Reindeer herding and harvesting of fur seals for pelts and meat

occur on St. Paul Island. Small herds of reindeer and cattle are

on Umnak Island. Tourism and wild-land recreation are

becoming increasingly important. Subsistence hunting, fishing,

and gathering provide food and a variety of other resources to

local residents and are a major component of the local

economy.

The major soil resource management concerns are water

erosion and mass wasting of soils that formed in volcanic ash

and cinders, particularly on steep slopes. Minimizing the

degree and extent of surface disturbance during construction

helps to control erosion. Overgrazing by reindeer is a local

concern. Control of animal numbers and proper herd

management can help to prevent overgrazing and allow natural

restoration of depleted range. 
569

Figure X1-1: Location of Land Resource Region X1.

X1—Interior Alaska

This region includes the vast interior of Alaska, from the

south slope of the Brooks Range to the north slope of the

Alaska Range (fig. X1-1). It also includes the Copper River

Basin and its surrounding mountains. The region makes up

259,260 square miles (671,835 square kilometers).

This region consists of flood plains, broad alluvial plains

and terraces, hills, mountain slopes, and ridges. Elevation

ranges from 100 feet (30 meters) in an area along the Yukon

River in the western part of the region to 20,320 feet (6,195

meters) on the summit of Mt. McKinley. The mountains

surrounding the region consist of folded and faulted strata that

were extensively glaciated during the Pleistocene epoch.

Almost all parts of the region below the highest mountain

peaks are unglaciated. The intermountain basins of the Yukon

Flats and Interior Alaska Lowlands are broad Pleistocene and

Holocene flood plains and terraces. The Copper River Plateau,

to the southeast, is a higher basin with broad alluvial and

lacustrine terraces and glacial landforms. The Yukon, Tanana,

and Kuskokwim Rivers drain most of this region to the west

into the Bering Sea. In most of the Copper River Basin,

drainage is into the Gulf of Alaska via the Copper River.

The subarctic continental climate in this region is dry and

cold. It is characterized by short, warm summers and long, cold

winters. The mean annual precipitation ranges from about 6

inches (150 millimeters) in the northwest lowlands to 100

inches or more (2,540 millimeters) in the Alaska Range. In

summer, afternoon thunderstorms are common in valleys and at

the lower elevations in the mountains. Lightning-caused

wildfires often burn many thousands of acres. The mean annual

temperature ranges from 8 to 28 degrees F (-13 to -2 degrees C).

It varies most in the mountainous areas. Freezing temperatures

may occur in any month in most of the region.

The total withdrawals of freshwater in this region average

about 51 million gallons per day (195 million liters per day).

About 79 percent is from surface water sources, and 21 percent

is from ground water sources. Nearly 80 percent of the water is

used for mining, agriculture, or the timber industry or for

cooling thermoelectric power plants near Fairbanks. The rest

generally is used for public supply in Fairbanks.
570 Major Land Resource Areas

Figure X1-2: Agricultural development in an area of Land Resource Region X1.

This region is in the zone of discontinuous permafrost. Not

all of the soils have permafrost in their profile. With a

temperature near 30 degrees F (-1 degree C), the permafrost in

this region is warmer than that in the Northern Alaska Region

(LRR Y). Distribution of the permafrost-affected soils is

determined by landform position, particle size, and moisture

content of the soils. Much of the area on the flanks of the

Brooks Range and Alaska Range is covered by rock, snow, and

ice. Gelisols and Inceptisols are the dominant soils. The soils in

the region have a cryic soil temperature regime or a subgelic

soil temperature class, a udic or aquic soil moisture regime, and

dominantly mixed mineralogy. In areas on mountain slopes,

Orthels and Turbels are intermixed with Gelepts and Gelolls. In

these areas, the soils that are not affected by permafrost formed

in the coarser textured materials on the steeper slopes. Orthels

and Turbels are intermixed with Cryepts on low hills and

mountains. An even mixture of Gelisols and Inceptisols

dominates the basins. The Inceptisols have a more recent

history of fire than the Gelisols. Wildfires disturb the insulating

organic material at the surface, lowering the permafrost layer

and eliminating perched water tables from these former

Gelisols. Depending on the frequency of the fires, landform

position, and particle size, these Inceptisols may or may not

revert back to Gelisols. Histosols are in depressions throughout

the region. Organic soils include Histels with permafrost and

Hemists without permafrost. Spodosols and Andisols are of

limited extent in the region. Cryods are in scattered areas in

some of the mountainous parts of the region. Cryands are in

parts of the Yukon-Kuskokwim Highlands.

The native vegetation across the region ranges from boreal

forests to alpine tundra. The southern Brooks Range and the

flanks of the Alaska Range are dominated by alpine tundra with

grasses, sedges, mosses, lichens, ericaceous shrubs, and willows.

The low hills and mountains have a mixture of alpine tundra

and boreal forests. The basins are dominantly boreal forests

with black spruce, white spruce, paper birch, and quaking

aspen.

Much of this region is sparsely populated wild land. Land

use along the Yukon River and in some other parts of the region

is diverse and includes urban development and rural settlement,

agriculture (fig. X1-2), forestry, mining, subsistence hunting

and fishing, and wildlife habitat. 
of the United States 571

Figure 227-1: Location of MLRA 227 in Land Resource Region X1.

227—Copper River Basin

This area is in the Interior Region of Alaska (fig. 227-1). It

includes the Talkeetna, Chugach, and Wrangell Mountains and

the Copper River Plateau, a broad intermontane basin bordered

by the Alaska Range. The MLRA makes up about 4,590 square

miles (11,900 square kilometers). Although the area is traversed

by the Richardson, Glenn, and Edgerton Highways, it is mostly

undeveloped wild land and is sparsely populated. The largest

community is Glennallen, at the intersection of the Richardson

and Glenn Highways. The smaller communities in the area

include Chitina, Copper Center, Gulkana, and Kenny Lake. Part

of the Wrangell-St. Elias National Park and Preserve is in this

area. The Trans-Alaska Pipeline parallels the Richardson

Highway through the area.

Physiography

This area lies within the Coastal Trough Province of the

Pacific Mountains System. It is mainly on nearly level to

undulating plains and rolling hills. Many depressions and

shallow basins on the plains have lakes and interconnecting

wetlands, particularly in the western and northern parts of the

area. Narrow flood plains and stream terraces are along the

rivers and streams. In many areas the rivers are deeply incised

with high escarpments and breaks between the river bottom and

adjacent plains. Isolated, low- to moderate-relief mountains are

in the northern and western parts of the area. Long footslopes

are common at the base of the mountains. In general, elevation

ranges from about 600 feet (185 meters) along the Copper River

at Chitina to about 2,600 feet (795 meters) along the edge of

the basin. The highest point in the area, at Windy Point on

Slide Mountain, is 3,806 feet (1,160 meters).

The only Hydrologic Unit Area (identified by a four-digit

number) that makes up this MLRA is South Central Alaska

(1905). The Copper River drains most of the area through the

Chugach Mountains to the Gulf of Alaska. The major tributaries

of the Copper River are the Gulkana, Gakona, Tazlina, and

Chitina Rivers. The largest lakes are Lake Louise, Susitna Lake,

Crosswind Lake, and Ewan Lake. Lakes make up about 10

percent of the area.

This area is in the zone of discontinuous permafrost.

Permafrost is commonly close to the surface in areas of the

finer textured sediments on plains, stream terraces, and the

more gently sloping footslopes and hills. Isolated masses of

ground ice occur in thick deposits of loess on terraces and the

lower side slopes of hills. Permafrost generally does not occur

on flood plains and in close proximity to lakes and other

water bodies.

Geology

During the latter part of the Pleistocene epoch, glacial ice

dammed the Copper River drainage, forming a large proglacial

lake in the center of the basin. Glaciers from the surrounding

mountains extended into the basin, probably calving into the

lake much of the time. At the onset of the Holocene epoch, the

glaciers receded and the lake emptied, exposing a broad, nearly

level to rolling plain. The central basin is filled with clayey

lacustrine deposits that become progressively more silty

toward the outer margins of the former lake. Slightly modified

glacial moraines, drift, and occasional drumlins and eskers are

above the level of the former lake. During the Holocene epoch,

the rivers and streams in the area cut into the lacustrine

deposits, creating low to high escarpments and depositing

coarse textured alluvium on flood plains and stream terraces. A

layer of calcareous, silty loess of varying thickness mantles

much of the modern landscape. Quaternary and Tertiary

volcanic rocks are exposed along river escarpments in the

southeastern part of the area. Isolated mountains in the basin

formed in stratified sedimentary rocks of Permian and

Pennsylvanian age.

Climate

The average annual precipitation in this area ranges from

about 10 inches (255 millimeters) in the central basin to more

than 20 inches (510 millimeters) at the higher elevations in the

northern and western parts of the area. Brief, warm summers and

long, cold winters characterize the subarctic continental

climate of the area. The average annual snowfall ranges from

about 40 to 70 inches (100 to 180 centimeters). The average

annual temperature ranges from about 23 to 28 degrees F (-5 to
572 Major Land Resource Areas

-2 degrees C). The freeze-free period averages 35 to 90 days.

Freezing temperatures are not unusual in summer, particularly

at the higher elevations.

Water

There are very limited withdrawals of freshwater for use in

this sparsely populated MLRA. The only measurable

withdrawal is for agricultural and logging activities (0.1

million gallons, or 0.4 million liters, per day). Most of the

communities in this area are along the three major roads

crossing the area or along the major rivers or lakes. Because of

its chemical quality, the surface water in the area generally is

suitable for all uses, but the rivers are frozen for much of the

year or flow little during winter. Also, the rivers are typically

fed by glacial meltwater, which carries high loads of suspended

sediment. If surface water is available, treatment for removal of

the suspended sediment would normally be required. For these

reasons, most of the water used for domestic supply in this area

is probably obtained from private wells.

Small communities and rural landowners probably obtain

ground water either from bedrock aquifers or from

unconsolidated sediments in river valleys (alluvium or glacial

outwash). There are typically no test data available on ground

water in sparsely populated areas. If these aquifers are close to

the surface, they are highly susceptible to contamination from

surface activities. Septic systems, landfills, and leaking fuel

storage tanks are all possible sources of contamination.

Soils

The dominant soil orders in this MLRA are Gelisols,

Inceptisols, Spodosols, Entisols, and Mollisols. The soils in the

area have a subgelic soil temperature class or a cryic soil

temperature regime, an aquic or udic soil moisture regime, and

dominantly mixed mineralogy.

Poorly drained Histoturbels (Dadina and Klawasi series) and

Aquiturbels (Klanelneechena and Strelna series) are

interspersed with well drained Eutrocryepts (Pippin and

Gulkana series) and Haplocryolls (Kenny Lake and Tonsina

series) on stream terraces, lacustrine terraces, till plains, and

hills. These soils formed either in thick deposits of loess or in a

mantle of loess over clayey lacustrine sediments or gravelly till

and outwash. The Inceptisols and Mollisols in the area have a

more recent history of fire than the Gelisols. Wildfires can

disturb the insulating organic material at the surface, lowering

the permafrost layer, eliminating perched water tables from

Gelisols, and thus changing the classification. Depending on

the frequency of the fires, landform position, and particle size,

these soils may or may not revert back to Gelisols. Fibristels

and Hemistels (Wrangell series) are in depressions. These

organic soils are shallow or moderately deep to permafrost and

are poorly drained or very poorly drained. Cryofluvents

(Klutina series) and Cryorthents (Gakona series) formed in

loamy alluvium over gravelly alluvium on flood plains and low

terraces.

Miscellaneous (nonsoil) areas make up about 12 percent of

this MLRA. The most common miscellaneous areas are

riverwash and water.

Biological Resources

On productive, well drained soils in the uplands, forest

vegetation includes white spruce, aspen, and paper birch. White

spruce and white spruce-balsam poplar forests are on high flood

plains and low stream terraces. Stunted black spruce and white

spruce woodland of low productivity is on north-facing slopes,

high stream terraces, and cold, wet sites with shallow

permafrost. Following wildfires, willow, shrub birch, and

ericaceous shrub scrub invade most sites until they eventually

are replaced by forest vegetation. On most forest and woodland

sites, post-fire succession leads to a relatively rapid

accumulation of organic matter and mosses on the surface. This

accumulation results in a decrease in soil temperature, biologic

activity, and nutrient availability and a gradual decrease in site

productivity. Nonforest vegetation in areas of peat, in

drainageways, and above tree line includes low to tall willow,

shrub birch, and ericaceous shrub scrub. Wet sedge meadows,

sedge-grass meadows, and sedge-moss bog meadows are along

the margins of lakes and on continuously ponded sites. Willow

and alder scrub are on low flood plains.

The common species of mammals in the area include brown

bear, black bear, caribou, moose, wolf, and a variety of

rodents. Ponds and wetlands provide high-quality habitat for

tundra swans and other waterfowl. Bald eagles are common

along most rivers. The rivers and lakes in the area support lake

trout, rainbow trout, grayling, burbot, northern pike, and

whitefish.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—8%

Forest—80%

Water—10%

Other—2%

Several small farms are in the Kenny Lake area in this

MLRA. Grasses, small grains, potatoes, and cool-season

vegetables are grown on less than 1 percent of the MLRA.

Small-scale timber harvesting occurs in a few places. Each year,

hunting, fishing, boating, hiking, and other kinds of wild-land

recreation attract thousands of visitors to the area. Subsistence

hunting, fishing, and gathering provide food and a variety of

other resources to both native and nonnative residents. Less

than 1 percent of the area is urban.

The major soil resource concerns are wind erosion and water

erosion in areas where the native vegetation has been removed.
of the United States 573

Disturbance of the insulating organic material at the surface

results in thawing of the upper soil layers. This thawing can

result in ponding, soil subsidence, erosion, and disruption of

surface drainage. All management activities should include

protection of the organic surface material and the thermal

balance of the soils. 

Figure 228-1: Location of MLRA 228 in Land Resource Region X1.

228—Interior Alaska Mountains

This area is in the Interior Region of Alaska (fig. 228-1). It

includes the high mountain slopes and glaciated hills and

plains of the Alaska Range, Talkeetna Mountains, Chugach

Mountains, Wrangell Mountains, and the northern Aleutian

Range. It makes up about 44,375 square miles (114,985 square

kilometers). Except for some remote lodges and a few small

communities along the Parks and Richardson Highways, which

bisect the mountains in three places, this MLRA is primarily

undeveloped wild land. Parts of Denali National Park and

Preserve, Wrangell-St. Elias National Park and Preserve, and

Tetlin National Wildlife Refuge are in this area. The TransAlaska Pipeline parallels the Richardson Highway from Paxson

to Delta Junction.

Physiography

The part of this area in the Aleutian and Alaska Ranges lies

within the Alaska-Aleutian Province of the Pacific Mountains

System. The part in the Chugach and Wrangell Mountains lies

within the Pacific Border Ranges Province of the same system,

and the part in the Talkeetna Mountains lies within the Coastal

Trough Province. The area consists of rugged, high mountains

and low, rounded hills and extended footslopes along the base

of the mountains. Throughout the area, the mountains are

deeply dissected by narrow to broad, high-gradient valleys,

typically with braided flood plains on the valley bottoms.

Coalescing fans and steep footslopes are common in the

valleys. Large valley glaciers occur throughout the area.

Glaciers and permanent ice and snow make up about 15 percent

of the area. Elevation ranges from about 1,500 feet (455 meters)

near Paxson in the basin of the Copper River to 20,320 feet

(6,195 meters) at the summit of Mt. McKinley.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

South Central Alaska (1905), 46 percent; Yukon (1903), 38

percent; and Southwest Alaska (1904), 16 percent. Surface

water on the north slopes of the Aleutian and Alaska Ranges

drains into the Bering Sea via the Tanana and Kuskokwim

Rivers. The major tributaries of the Kuskokwim River are the

Stony River and the North Fork of the Kuskokwim River. The

major tributaries of the Tanana River are the Kantishna,

Nenana, Delta, and Nabesna Rivers. Surface water in the

mountains bordering the basin of the Copper River drains into

the Copper River and the Gulf of Alaska and North Pacific. The

major tributaries of the Copper River are the Gulkana, Tazlina,

and Chitina Rivers. The headwaters of the Susitna River, which

drains into the Cook Inlet Lowlands (MLRA 224) and Cook

Inlet, are in this MLRA. Lakes and ponds make up less than 1

percent of the area. There are, however, a number of large lakes

and lake systems in the area, including Tazlina, Klutina, and

Tonsina Lakes in the Chugach Mountains and Paxson Lake

and the Tangle Lakes system in the Alaska Range.

This area is in the zone of discontinuous permafrost.

Generally, permafrost is close to the surface only in areas of

the finer textured sediments on stream terraces and in swales

on hills and footslopes. In the mountains, permafrost

occurs only in gently sloping areas of rounded ridges,

swales, and footslopes. Flood plains generally have no

permafrost.

Geology

During the late Pleistocene epoch, all of this area was

covered with glacial ice, except for the highest peaks and steep

upper ridges. For the most part, glacial deposits eroded away or

were buried by mountain colluvium and alluvium, which

accumulated during the Holocene epoch across about 60

percent of the landscape. Slightly modified to highly modified

glacial moraines, drift, and outwash deposits are extensive on

the lower mountain slopes and in valleys at the lower

elevations. Silty eolian deposits are limited to the lower

mountain slopes and valleys. Valley bottoms are buried by
574 Major Land Resource Areas

recent fluvial deposits. The bedrock geology consists primarily

of upper Paleozoic and Mesozoic sedimentary, metamorphic,

and igneous rocks and Tertiary intrusive and volcanic rocks.

The Usibelli Coal Mine and some commercial and recreational

gold mines occur in this area.

Climate

The average annual precipitation ranges from about 15 to 20

inches (380 to 510 millimeters) at the lower elevations in this

area. It is as much as 100 inches (2,540 millimeters) at the

highest elevations in the Alaska Range and Wrangell

Mountains. The amount of rainfall generally is highest in July,

August, and early September. Brief, cool summers and long,

cold winters characterize the subarctic continental climate of

the area. The extreme variation in elevation in this MLRA

results in a wide range of climatic conditions. The average

annual snowfall ranges from about 70 to 400 inches (180 to

1,015 centimeters). The average annual temperature at

McKinley Park headquarters in the Alaska Range is 27 degrees

F (-3 degrees C). The freeze-free period averages about 50 to 80

days. At the higher elevations, freezing temperatures can occur

during every month.

Water

There are very limited withdrawals of freshwater for use in

this sparsely populated MLRA. The only measurable

withdrawal is for mining operations (0.3 million gallons, or 1.1

million liters, per day). Most of the communities in the area are

along the major rivers. Because of its chemical quality, the

surface water in the area generally is suitable for all uses, but

the rivers are frozen for much of the year or flow little during

winter. Also, the rivers are typically fed by glacial meltwater,

which carries high loads of suspended sediment. If surface water

is available, treatment for removal of the suspended sediment

would normally be required. For these reasons, most of the

water used for domestic supply in this area is probably obtained

from private wells.

Small communities and rural landowners probably obtain

ground water either from bedrock aquifers or from

unconsolidated sediments in river valleys (alluvium or glacial

outwash). There are typically no test data available on ground

water in sparsely populated areas. If these aquifers are close to

the surface, they are highly susceptible to contamination from

surface activities. Septic systems, landfills, leaking fuel storage

tanks, and industrial waste from coal and gold mining are all

possible sources of contamination.

Soils

The dominant soil orders in this MLRA are Gelisols,

Inceptisols, Spodosols, and Entisols. The soils in the area have

a subgelic soil temperature class or a cryic soil temperature

regime, an aquic or udic soil moisture regime, and mixed

mineralogy.

Histoturbels and Aquiturbels on mountain slopes, hills, and

plains formed in loamy and gravelly glacial till. These soils are

shallow or moderately deep to permafrost and generally are

poorly drained. Gelepts and Cryepts on steep mountain slopes

formed in gravelly colluvium over fractured bedrock. These

soils do not have permafrost, are shallow to very deep, and are

well drained. Haplocryods on outwash plains, hills, and terraces

formed in a thin layer of silty eolian deposits over sandy and

gravelly outwash and alluvium. These soils are somewhat

excessively drained. Cryofluvents and Cryorthents on flood

plains formed in loamy alluvium over sandy and gravelly

alluvium. These soils are somewhat poorly drained to well

drained.

Miscellaneous (nonsoil) areas make up about 58 percent of

this MLRA. The most common miscellaneous areas are rock

outcrop, rubble land, and glaciers.

Biological Resources

This MLRA includes the true alpine and the subalpine

zones. Alpine vegetation consists of a variety of dwarf scrub

and herbaceous communities. Black crowberry, ericaceous

shrubs, dwarf willow, or dryas typically dominates dwarf scrub.

Various sedges, grasses, and low forbs dominate in herbaceous

communities. Low willow scrub is common in drainages.

Lichens, scattered herbs, and dwarf shrubs dominate bedrock

exposures and very shallow soils. In general, there is little or no

plant growth above elevations of about 7,500 feet (2,285

meters). The vegetation in the subalpine zone generally is low

and medium scrub dominated by shrub birch and ericaceous

shrubs that grade into white spruce woodlands at the lower

elevations. Tall alder scrub is common in many places.

Some of the major species of mammals in the area are brown

bear, black bear, Dall sheep, caribou, moose, wolf, coyote, fox,

snowshoe hare, arctic ground squirrel, and hoary marmot.

Ptarmigan, American golden plovers, golden eagles, and a wide

variety of other birds are common in many places.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—30%

Forest—12%

Water—1%

Other—57%

Remote wild-land recreation is the principal land use in this

area. The rugged mountains, extensive glaciers, and wilderness

qualities of the area attract hikers and wilderness enthusiasts

from around the world. Every summer, hundreds of climbers

attempt to climb Mt. McKinley and other high peaks in the

area. More people visit Denali National Park than any other
of the United States 575

park in Alaska. Hunters pursue moose, caribou, Dall sheep,

brown bear, and black bear. Back-country recreationists and

hunters are served by air taxi, guiding, and outfitting

companies operating out of the major Alaska communities.

Mining formerly was a major land use that helped to support

development on nearby lowlands. The Usibelli Coal Mine is a

large-scale open-pit mine in the mountains near Healy. It

provides fuel for electrical generator plants in Fairbanks and

elsewhere in Alaska. Small-scale commercial and recreational

gold mines operate along a number of streams. There are no

major resource concerns in this area. 

Figure 229-1: Location of MLRA 229 in Land Resource Region X1.

229—Interior Alaska Lowlands

This area is in the Interior Region of Alaska and includes the

flood plains and terraces along the upper reaches of the Tanana

and Kuskokwim Rivers and the middle reaches of the Yukon

River (fig. 229-1). The area makes up about 36,320 square

miles (94,120 square kilometers). The southwest part of this

MLRA and nearby portions of the Interior Alaska Highlands

(MLRA 231) are the second most densely populated areas in

Alaska. The areas along the road system include the

municipality of Fairbanks; the towns of Nenana, Delta

Junction, and Tok; and parts of Fort Wainwright and Fort

Greely, the two largest military reservations in Alaska.

Elsewhere, the area is mostly undeveloped wild land and is

sparsely populated. In the western part of the area, the

communities of Tanana, Galena, and McGrath are accessible

only by air or by river. Parts of the Denali National Park and

Preserve and Tetlin National Wildlife Refuge are in this area.

The Trans-Alaska Pipeline parallels the Alaska Highway from

Delta Junction to Fairbanks.

Physiography

This area lies within the Western Alaska and Northern

Uplands and Lowlands Provinces of the Intermontane

Uplands and Lowlands System. The area is on broad, nearly

level, braided to meandering flood plains, stream terraces, and

outwash plains. In many places shallow basins and undulating

stream terraces are dotted with hundreds of small and mediumsize lakes and interconnecting wetlands. Sloughs, oxbow

lakes, and low to high escarpments along river channels are

features associated with the flood plains, terraces, and basins.

Isolated bedrock-controlled hills and low- to moderate-relief

mountains are in scattered areas throughout the MLRA.

Extended footslopes are common at the base of hills and

mountains and along the boundaries with adjoining

mountainous MLRAs. Elevation ranges from about 100 feet (30

meters) in the southwestern part of the area, along the lower

Yukon River, to about 1,900 feet (580 meters) in the upper

Tanana Valley.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Yukon (1903), 75 percent, and Southwest Alaska (1904), 25

percent. Surface water in all of the area drains to the Bering Sea

via the Tanana, Yukon, and Kuskokwim Rivers. The major

tributaries of the Tanana River are the Kantishna, Nenana,

Delta, and Nabesna Rivers. The major tributaries of the Yukon

River, in addition to the Tanana River, are the Koyukuk and

Innoko Rivers. The major tributaries of the Kuskokwim River

are the Stony River and the North Fork of the Kuskokwim

River. Lakes make up about 10 percent of the area.

This area is in the zone of discontinuous permafrost.

Permafrost commonly is close to the surface in areas of the finer

textured sediments on plains, stream terraces, and the more

gently sloping footslopes and hills. Isolated masses of ground

ice occur in thick deposits of loess on terraces and the lower

side slopes of hills. Permafrost generally does not occur on

flood plains and in areas near lakes and other water bodies.

Geology

Although never glaciated, this area is filled with a deep layer

of Pleistocene glaciofluvial deposits. Additional fluvial

sediments from the Alaska Range and the northern Aleutian

Range accumulated along the Tanana and Kuskokwim Rivers

during the Holocene epoch. The Koyukuk and lower Yukon

River drainages have undergone several periods of deposition

followed by erosion. In places old terraces are 33 to 250 feet

(10 to 75 meters) above the flood plain. Quaternary

glaciofluvial and fluvial sediments are estimated to be as much

as 330 to 660 feet (100 to 200 meters) thick throughout the
576 Major Land Resource Areas

area. Much of the area, particularly along the Tanana and

Kuskokwim Rivers, is mantled with a layer of silty micaceous

loess originating from the unvegetated flood plains and

outwash plains along the Alaska Range. Thick eolian deposits,

including loess and sand dunes, make up about 12 percent of

the area. Near the mountains are inclusions of glacial moraines

and drift. Unconsolidated sediments bury the bedrock geology

in this area, except for occasional structural hills.

Climate

The average annual precipitation ranges from 10 to 15

inches (255 to 380 millimeters) in the eastern and northern

parts of this area and from 15 to 20 inches (380 to 510

millimeters) in the southern and western parts. The maximum

precipitation occurs in late summer, mainly during

thunderstorms. Short, warm summers and long, very cold

winters characterize the subarctic continental climate of the

area. The average annual snowfall ranges from 30 to 80 inches

(75 to 205 centimeters). The average annual temperature ranges

from about 22 degrees F in the eastern part of the area to 28

degrees F (-6 to -4 degrees C) in the western part. The freezefree period averages about 70 to 120 days. The temperature

usually remains above freezing from June through midSeptember.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 10.6%; ground water, 8.7%

Livestock—surface water, 0.4%; ground water, 0.0%

Irrigation—surface water, 0.4%; ground water, 0.2%

Other—surface water, 68.3%; ground water, 11.4%

The total withdrawals average 48 million gallons per day

(180 million liters per day). About 20 percent is from ground

water sources, and 80 percent is from surface water sources. In

most years precipitation is adequate for crops, but in some years

yields are reduced by short dry periods in summer. Permanent

streams, originating in the mountainous regions surrounding

this area, bring water to nearly all parts of the MLRA. The area

has numerous large natural lakes and some constructed

reservoirs. The surface water is used for public supply, placer

mining, cooling thermoelectric power plants, and some limited

irrigation. It is generally suitable for all uses. Rivers fed by

glacial meltwater streams below placer mines typically carry

high loads of suspended sediment. Flooding from ice dams that

form during the spring thaw is a concern in this area.

The ground water used in this area is primarily from

unconsolidated sediments in river valleys (alluvium) or from

buried glacial outwash deposits in the river valleys. This water

is hard or very hard but is otherwise of excellent quality. Wells

in these aquifers generally are shallow, and the aquifers are

being constantly recharged with freshwater (rainfall and runoff).

As a result, the median level of total dissolved solids is fairly

low, about 190 parts per million (milligrams per liter). The level

of iron greatly exceeds the secondary standard for drinking

water of 300 parts per billion (micrograms per liter). This

standard is for esthetics. The iron can stain ceramic and

porcelain and precipitate in pipes. Since the aquifers are close

to the surface and water moves through them quickly, they are

highly susceptible to contamination from runoff. Septic

systems, landfills, and leaking fuel storage tanks are all

possible sources of contamination.

Some ground water can be obtained from the FairbanksNorth Star bedrock aquifer near Fairbanks and unnamed

bedrock aquifers in other parts of the area. Except for lower

levels of iron, the water in the unnamed bedrock aquifers is

similar in quality to that in the unconsolidated sediments. The

water in the Fairbanks-North Star aquifer is harder than that in

the unconsolidated sediments, and its median level of total

dissolved solids is about 400 parts per million (milligrams per

liter). The level of iron is similar to that of the water in the

alluvium or outwash. The median level of arsenic is 9 to 10

parts per billion (micrograms per liter) in water from both the

unconsolidated sediments and the Fairbanks-North Star

bedrock aquifer, but some tests indicate that the water from the

bedrock aquifer can exceed the national drinking water

standard of 50 parts per billion (micrograms per liter).

Soils

The dominant soil orders in this area are Gelisols,

Inceptisols, Entisols, and Spodosols. The soils in the area

have a subgelic soil temperature class or a cryic soil

temperature regime, an aquic or udic soil moisture regime, and

dominantly mixed mineralogy. Many of the soils have a

significant content of mica that was derived from source parent

materials.

Aquiturbels (Tanana series) and Histoturbels (Tanacross

series) on nearly level stream terraces and outwash plains

formed in silty loess of varying thickness over loamy, sandy,

and gravelly alluvial deposits. On elongated footslopes, these

soils formed in silty loess over loamy slope alluvium and

colluvium. Hemistels (Bolio series) and Fibristels (Lemeta

series) in depressions on stream terraces, outwash plains, and

elongated footslopes formed in thick layers of organic material.

All of the Gelisols are shallow or moderately deep to permafrost

and are poorly drained or very poorly drained. Wildfires can

disturb the insulating organic material at the surface, lowering

the permafrost layer, eliminating perched water tables from

Gelisols, and thus changing the classification. Depending on

the frequency of the fires, landform position, and particle size,

these soils may or may not revert back to Gelisols. Eutrocryepts

(Volkmar series), Dystrocryepts (Zitziana series), Cryaquepts

(Liscum series), and Haplocryods occur on the same landforms

and formed in the same kind of material as the Gelisols. Unlike
of the United States 577

the Gelisols, they do not have permafrost within the soil profile.

The Eutrocryepts, Dystrocryepts, and Haplocryods are well

drained to excessively drained, and the Cryaquepts are poorly

drained or very poorly drained. Cryorthents (Chena series) and

Cryofluvents (Jarvis and Salchaket series) on flood plains and

low stream terraces formed in stratified silty, sandy, and

gravelly alluvium. These Entisols range from moderately well

drained to excessively drained. Very poorly drained

Cryofibrists along the margins of lakes and in shallow basins

formed in floating fibrous peat.

Miscellaneous (nonsoil) areas make up about 19 percent of

this MLRA. The most common miscellaneous areas are

riverwash and water.

Biological Resources

Forests on productive, well drained soils in the uplands

include white spruce and mixed white spruce, paper birch, and

quaking aspen. White spruce and white spruce-balsam poplar

forests are on high flood plains and low stream terraces. Stunted

black spruce and white spruce woodland of low productivity

occurs on north-facing slopes, high stream terraces, and cold,

wet sites with shallow permafrost. On permafrost-affected flats,

tamarack and paper birch occur in association with spruce.

Lightning-caused wildfires are common, often burning many

thousands of acres during a single fire. Following wildfires,

willow, shrub birch, and ericaceous shrub scrub invade most

sites until they eventually are replaced by forest vegetation. On

all forest and woodland sites, post-fire succession leads to a

relatively rapid accumulation of organic matter and mosses on

the surface. This accumulation results in decreased soil

temperature, biologic activity, and nutrient availability and a

gradual decrease in site productivity. Nonforest vegetation

includes low to tall willow, shrub birch, and ericaceous shrub

scrub in areas of peat and in drainageways. Wet sedge meadows,

sedge-moss bog meadows, and sedge-grass meadows are along

the margins of lakes and on continuously ponded sites. Low to

tall willow and alder scrub are on low flood plains.

The common species of mammals in the area include brown

bear, black bear, caribou, moose, wolf, lynx, and a variety of

rodents. Ponds and wetlands provide high-quality habitat for

tundra swans, sandhill cranes, and other waterfowl. Bald eagles

are common along most rivers. The rivers and lakes in the area

support salmon, lake trout, rainbow trout, arctic grayling,

burbot, northern pike, blackfish, and whitefish.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—1%

Grassland—20%

Forest—60%

Water—10%

Other—9%

Farming is a major land use in the Tanana Valley near

Fairbanks and Delta Junction. Grasses, small grains, potatoes,

and other cool-season vegetables are the principal crops. Some

dairy cattle, beef cattle, and hogs are raised on this farmland.

The flood plains and low stream terraces along the Tanana and

Yukon Rivers are among the most productive forestlands in

Interior Alaska. Logging provides important wood products for

local use and export. Extractable minerals, dominantly gold

and silver, occur in certain areas. Placer mining along the rivers

and placer and hard rock mining in the adjacent Interior Alaska

Highlands (MLRA 231) helped to support settlement and

development in the area. Wild-land recreation, primarily

hunting for moose and other game, is a significant land use in

the area. Many residents rely on subsistence hunting, fishing,

and gathering for a large part of their food. Urban development,

particularly along the road system, has impacted less than 1

prcent of the area. Urban development and road construction

require a significant quantity of construction material, and

gravel pits of various sizes are along the major roads and near

urban developments.

The major soil resource concerns are wind erosion and water

erosion in areas where the native vegetation has been removed.

Most urban and rural developments are adjacent to rivers, in

areas where flooding is a severe hazard. Flooding is associated

with spring snowmelt and runoff from the adjacent mountains

and ice jamming at river bends during periods of ice breakup.

Conservation practices on forestland generally include

timber stand improvement and proper construction of roads,

landings, and stream crossings. Erosion- and sediment-control

practices are important in the areas used for urban

development. 

230—Yukon-Kuskokwim Highlands

This area is in the Interior Region of Alaska and includes the

mountains, hills, and valleys of the Lime Hills, the Kuskokwim

Mountains, and the eastern side of the Nulato Hills (fig. 230-1).

The area makes up about 59,860 square miles (155,115 square

kilometers). It is mostly undeveloped wild land and is sparsely

populated. The principal communities, which are along the

banks of the major rivers, are Sleetmute, Lime Village, and

Takotna. A number of other communities that supported past

hard rock mining operations have been abandoned. Parts of the

Nowitna National Wildlife Refuge and Lake Clark National

Park and Preserve are in this area.

Physiography

This area lies within the Western Alaska Province of the

Intermontane Uplands and Lowlands System. It is on moderateto high-relief mountains and in narrow, flat-bottomed valleys.

The highest local relief is in the Kuskokwim Mountains. Local

relief in the Nulato, Nushagak, and Lime Hills is generally
578 Major Land Resource Areas

Figure 230-1: Location of MLRA 230 in Land Resource Region X1.

lower. Most of the mountains at the mid and higher elevations

have gently sloping to strongly sloping, rounded summits. In a

few places, particularly at the highest elevations in the

Kuskokwim Mountains, the mountains are more rugged and

have sharp ridges. Valley bottoms consist of nearly level flood

plains and stream terraces, which give rise to moderately steep

mountain footslopes and alluvial and colluvial fans at the base

of the mountains. Elevation ranges from about 30 feet (9

meters) in the western part of the area, along the edge of the

Yukon-Kuskokwim Coastal Plain (MLRA 238), to 4,508 feet

(1,374 meters) at the summit of Von Frank Mountain, in the

southeastern Kuskokwim Mountains.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Yukon (1903), 54 percent; Southwest Alaska (1904), 44

percent; and Northwest Alaska (1902), 2 percent. Surface water

on the eastern slope of the Nulato Hills, the Kuskokwim

Mountains, and the western part of the Lime Hills drains into

the Bering Sea via the Yukon, Innoko, and Kuskokwim Rivers.

Surface water on the eastern and southern Lime Hills drains into

the Mulchatna and Nushagak Rivers and Bristol Bay. Lakes

make up about 7 percent of the area.

This area is in the zone of discontinuous permafrost.

Permafrost commonly is close to the surface in areas of the finer

textured sediments throughout the MLRA. Isolated masses of

ground ice occur in thick deposits of loess on terraces and the

lower side slopes of hills. The prevalence of permafrost

decreases to the southwest. Permafrost generally does not occur

on flood plains or on south-facing slopes on steep mountains.

Geology

During the Pleistocene epoch, the Lime Hills in the

southeastern part of this area were covered extensively by

glaciers originating in the Alaska Range and the northern

Aleutian Range. Glacial moraines and drift are common in this

part of the area. Elsewhere, the area generally was not glaciated

and uplands are covered primarily by bedrock colluvium and

slope alluvium originating from the underlying bedrock. Silty

loess deposits of limited extent cover footslopes and the lower

backslopes of hills near the major rivers. The bedrock geology

consists primarily of Cretaceous and lower Paleozoic stratified

sedimentary rocks and many, in places extensive, inclusions of

Cretaceous and Tertiary intrusive and volcanic rocks. The area

is cut by numerous northeast-trending faults. Quaternary fluvial

and eolian deposits cover valley bottoms and the lower

mountain slopes.

Climate

The average annual precipitation ranges from about 10 to 15

inches (255 to 380 millimeters) at the lower elevations in the

eastern part of this area to 20 to 40 inches (510 to 1,015

millimeters) at the higher elevations in the western and

southwestern parts. The climate is transitional from subarctic

continental in the eastern part of the area to maritime in the

southwestern part, along the boundary with the Western Region

of Alaska. The average annual snowfall ranges from about 80 to

100 inches (205 to 255 centimeters). The average annual

temperature is estimated to be about 20 to 25 degrees F (-7 to -4

degrees C). The freeze-free period at the lower elevations

averages about 60 to 80 days. Freezing temperatures may occur

in any month at the higher elevations.

Water

There are very limited withdrawals of freshwater for use in

this sparsely populated MLRA. Most of the communities in the

area are along the major rivers. Because of its chemical quality,

the surface water in the area generally is suitable for all uses,

but the rivers are frozen for much of the year or flow little

during winter. Also, the rivers are typically fed by glacial

meltwater, which carries high loads of suspended sediment. If

surface water is available, treatment for removal of the

suspended sediment would normally be required. For these

reasons, most of the water used for domestic supply in this area

is probably obtained from private wells.

Small communities and rural landowners probably obtain

ground water either from bedrock aquifers or from

unconsolidated sediments in river valleys (alluvium or glacial

outwash). There are typically no test data available on ground

water in sparsely populated areas. If these aquifers are close to

the surface, they are highly susceptible to contamination from
of the United States 579

surface activities. Septic systems, landfills, and leaking fuel

storage tanks are all possible sources of contamination.

Soils

The dominant soil orders in this MLRA are Gelisols,

Inceptisols, Spodosols, and Entisols. The soils in the area have

a subgelic soil temperature class or a cryic soil temperature

regime, an aquic or ustic soil moisture regime, and dominantly

mixed mineralogy.

Aquiturbels on long footslopes, on ridges above tree line,

and on solifluction lobes formed in gravelly colluvium or in

loess over gravelly colluvium. Histoturbels on north-facing

slopes, footslopes, rolling uplands, and valley bottoms formed

in moderately thick layers of organic material over loamy

colluvium or loess. Fibristels and Hemistels in depressions

(thermokarst depressions in places) on terraces and in swales on

hillslopes formed in thick layers of organic material. Gelisols

are shallow or moderately deep to permafrost and are poorly

drained or very poorly drained. Wildfires can disturb the

insulating organic material at the surface, lowering the

permafrost layer, eliminating perched water tables from

Gelisols, and thus changing the classification. Depending on

the frequency of the fires, landform position, and particle size,

these soils may or may not revert back to Gelisols.

Dystrocryepts and Eutrocryepts on the upper slopes and on

ridges formed in colluvium over fractured bedrock. Humicryods

and Haplocryods on south-facing slopes and stream terraces

formed in loess over loamy or gravelly alluvium. Inceptisols

and Spodosols do not have permafrost within their soil profile

and generally are well drained. Cryofluvents, Cryaquents, and

Cryorthents on flood plains formed in stratified loamy, sandy,

and very gravelly alluvium. These soils range from very poorly

drained to excessively well drained.

Miscellaneous (nonsoil) areas make up about 10 percent of

this MLRA. The most common miscellaneous areas are rock

outcrop and rubble land. In many valleys placer mine tailings

are common.

Biological Resources

The well drained soils on mountain slopes at low and midelevations are dominated by white spruce forests and

woodlands, mixed spruce-hardwood forests, tall alder shrub, tall

and low willow scrub, and low ericaceous scrub. Areas of peat

and moderately well drained mineral soils have black spruce

woodlands and low ericaceous and shrub birch scrub,

commonly with tussock-forming sedges or various sedges and

grasses in the ground layer. Drainages and lakeshores have wet

sedge meadows, sedge-grass meadows, and sedge-moss

meadows. Well drained soils on valley bottoms at the lower

elevations have white spruce, balsam poplar, and mixed balsam

poplar-white spruce forests. The higher elevations and the

shallow soils on mountain slopes and ridges commonly have

dwarf alpine scrub dominated by ericaceous shrub, dryas, and

shrub birch. These communities often have a considerable

amount of lichen cover and bare ground. Bedrock exposures

with only lichens and scattered shrubs and herbs in pockets of

fine earth dominate the highest elevations and ridges.

The common species of mammals in the area include brown

bear, black bear, moose, caribou, wolf, and a variety of small

mammals. Golden eagles and peregrine falcons nest on cliffs

along the major rivers and on rock outcrops on ridges at the

higher elevations. The rivers in the area support runs of salmon.

Arctic grayling are common in clear-water streams.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—25%

Forest—65%

Water—7%

Other—3%

Most of this area still supports natural vegetation and is used

primarily for subsistence hunting, fishing, and gathering by

local residents. Mining for gold, silver, and other extractable

minerals and commodities was a significant land use in the

past. Most of the mines have ceased operation. People from

outside the MLRA use the area for hunting and wild-land

recreation.

The major soil resource concerns are erosion of the shallow

soils on uplands and disturbance of the fragile permafrostaffected soils. Disturbance of the insulating organic material at

the surface results in thawing of the upper soil layers. This

thawing can result in ponding, soil subsidence, erosion, and

disruption of surface drainage. All management activities

should include protection of the organic surface material and

the thermal balance of the soils. 

231—Interior Alaska Highlands

This area is in the Interior Region of Alaska and includes the

extensive hills, low to moderately high mountains, and valleys

between the Tanana River to the south and the Brooks Range to

the north (fig. 231-1). The area makes up about 69,175 square

miles (179,255 square kilometers). It is traversed by a number

of major roads, including the Taylor Highway in the eastern

part of the area and the Steese, Elliott, and Dalton Highways

north of Fairbanks. The area is mostly undeveloped wild land

and is sparsely populated. The principal communities along the

road system are part of the municipality of Fairbanks and the

nearby communities of Eagle, Circle, Central, and Livengood.

The northwestern part of the area has a number of remote

villages, primarily along the major rivers. The Yukon-Charley
580 Major Land Resource Areas

Figure 231-1: Location of MLRA 231 in Land Resource Region X1.

Rivers National Park and Preserve, the White Mountains

National Recreation Area, part of the Yukon Flats National

Wildlife Refuge, and the Arctic National Wildlife Refuge are in

this MLRA. The Trans-Alaska Pipeline parallels the Elliott and

Dalton Highways from Fairbanks north to the Brooks Range.

Physiography

This area lies within the Northern Uplands and Lowlands

Province of the Intermontane Uplands and Lowlands System. It

is mostly on moderately steep or steep, moderate- to high-relief

hills and mountains and in narrow to broad, flat-bottomed

valleys. The mountains are generally rounded at the lower

elevations and sharp-ridged at the higher elevations. The

Davidson Mountains, in the northwestern part of the area, are

rounded to flat-topped at the higher elevations. Elevation

ranges from about 400 feet (120 meters) in the western part of

the area, along the boundary with the Interior Alaska Lowlands

(MLRA 229), to 6,583 feet (2,007 meters) at the summit of Mt.

Harper, in the southeastern part of the area.

The only Hydrologic Unit Area (identified by a four-digit

number) that makes up this MLRA is Yukon (1903). Surface

water in this MLRA drains into the Bering Sea via the Yukon,

Tanana, and Koyukuk Rivers. The major tributaries of the

Yukon River are the Porcupine, Chandalar, Fortymile, and

Charley Rivers. The major tributaries of the Tanana River are

the Goodpaster, Salcha, Chatanika, and Melozitna Rivers. The

upper Kanuti River is the major tributary of the Koyukuk River

in this area. Lakes make up less than 2 percent of the area.

This area is in the zone of discontinuous permafrost.

Permafrost commonly is close to the surface in areas of the finer

textured sediments throughout the MLRA. Isolated masses of

ground ice occur in thick deposits of loess on terraces and the

lower side slopes of hills. Permafrost generally does not occur

on flood plains and south-facing slopes on steep mountains.

Periglacial features, such as pingos, thermokarst pits and

mounds, ice-wedge polygons, and earth hummocks, are on the

lower slopes and in upland valleys, particularly in the

Davidson Mountains, in the northwestern part of the area.

Geology

This MLRA generally was glaciated during the Pleistocene

epoch only in the highest mountains and in the northern part of

the area, where glaciers extended into the area from the Brooks

Range. For the most part, glacial moraines and drift are limited

to the upper elevations of the highest mountains. Most of the

landscape is mantled with bedrock colluvium and slope

alluvium originating from the underlying bedrock. Valley

bottoms are filled with Holocene fluvial deposits and slope

alluvium from the adjacent mountain slopes. Silty loess, which

originated from unvegetated flood plains in and adjacent to this

area, covers much of the surface. On low hills near the major

river valleys, the loess is many feet thick. On high ridges, it is

less than 1 foot thick. Bedrock is exposed on the highest ridges.

The dominant bedrock types are Paleozoic sedimentary and

Permian through Jurassic igneous rocks in the northeastern part

of the area, Permian and lower Cretaceous sedimentary and

metamorphic rocks in the eastern part, and Precambrian and

Paleozoic metamorphic and sedimentary rocks with common

Cretaceous intrusives in the southwestern and western parts.

Climate

The average annual precipitation is less than 10 inches (255

millimeters) on valley bottoms and lowlands in the

northeastern part of this area and ranges from 20 to 40 inches

(510 to 1,015 millimeters) at the higher elevations. The

maximum rainfall occurs in late summer, mainly as a result of

thunderstorms. Short, warm summers and long, cold winters

characterize the subarctic continental climate of the area. The

average annual snowfall ranges from about 45 to 100 inches

(115 to 255 centimeters). The average annual temperature is

about 10 to 16 degrees F (-12 to -9 degrees C) in the northern

part of the area and 20 to 25 degrees F (-7 to -4 degrees C) in

the southern part. The freeze-free period at the lower elevations

averages about 60 to 100 days, and the temperature usually

remains above freezing from June through mid-September.
of the United States 581

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 20%; ground water, 15%

Livestock—surface water, 0%; ground water, 0%

Irrigation—surface water, 0%; ground water, 0%

Other—surface water, 40%; ground water, 25%

The total withdrawals average 2 million gallons per day (7.5

million liters per day). About 40 percent is from ground water

sources, and 60 percent is from surface water sources. In most

years precipitation is adequate for crops at the lower elevations,

but in some years yields are reduced by short dry periods in

summer. Permanent streams carry water to nearly all parts of the

area. The area has some natural lakes. The surface water in the

area is used primarily for public supply and the needs of the

forest products industry. It is generally suitable for all uses.

Rivers fed by glacial meltwater typically carry high loads of

suspended sediment. Flooding from ice dams that form during

the spring thaw is a concern in this area.

The ground water used in this area is primarily from

unconsolidated sediments in river valleys (alluvium) or from

buried glacial outwash deposits in river valleys or on uplands.

Most of the measurable water use from these aquifers occurs

along the southern edge of this area, near Fairbanks, and along

the boundary with the Yukon Flats Lowlands (MLRA 232).

This water is hard or very hard but is otherwise of excellent

quality. Wells in these aquifers generally are shallow, and the

aquifers are constantly recharged with freshwater (rainfall and

runoff). As a result, the median level of total dissolved solids is

fairly low, about 130 parts per million (milligrams per liter).

The level of iron may exceed the secondary standard for

drinking water of 300 parts per billion (micrograms per liter).

The secondary standard is for esthetics. The iron can stain

ceramic and porcelain and precipitate in pipes. Since the

aquifers are close to the surface and water moves through them

quickly, they are highly susceptible to contamination from

runoff. Septic systems, landfills, and leaking fuel storage tanks

are all possible sources of contamination.

Small amounts of ground water can be obtained from the

bedrock aquifer in this area. This water is similar in quality to

that in the unconsolidated sediments.

Soils

The dominant soil orders in this MLRA are Gelisols,

Inceptisols, Entisols, and Spodosols. The soils in the area have

a subgelic soil temperature class or a cryic soil temperature

regime, an aquic or udic soil moisture regime, and mixed

mineralogy. Many of the soils have a significant content of

mica derived from micaceous parent materials.

Histoturbels (Ester and Goldstream series), Aquiturbels

(Bradway and Chatanika series), and Haploturbels on northfacing slopes, on south-facing footslopes, and in valleys formed

in thick deposits of silty loess or in loess over loamy and

gravelly colluvium. On the steeper slopes, these soils

commonly have fractured bedrock in their soil profile. The

Gelisols on stream terraces formed in loamy alluvial deposits.

Fibristels (Lemeta series) and Hemistels (Bolio series) are in

depressions on stream terraces and footslopes and in swales on

hills and mountains. All of the Gelisols are shallow or

moderately deep to permafrost and are poorly drained or very

poorly drained. Wildfires can disturb the insulating organic

material at the surface, lowering the permafrost layer,

eliminating perched water tables from Gelisols, and thus

changing the classification. Depending on the frequency of the

fires, landform position, and particle size, these soils may or

may not revert back to Gelisols. Dystrocryepts (Brigadier and

Gilmore series), Eutrocryepts (Fairbanks and Steese series), and

Haplocryods formed in silty loess over loamy and gravelly

colluvium or in loamy and gravelly colluvium over fractured

bedrock on mountain slopes and hillslopes, especially southfacing slopes. On the lower slopes near the major rivers, these

soils formed in deposits of loess many feet thick. The loess

consists of both windblown material and colluvial silt that

eroded and washed down from the adjacent slopes. Inceptisols

and Spodosols do not have permafrost within their soil profile,

generally are moderately deep or deep, and are well drained.

Cryofluvents (Jarvis series) and Cryorthents (Chena series) on

flood plains formed in stratified loamy, sandy, and very

gravelly alluvium. These soils range from very poorly drained

to excessively well drained.

Miscellaneous (nonsoil) areas make up about 2 percent of

this MLRA. The most common miscellaneous areas are rock

outcrop and rubble land. In many valleys placer mine tailings

are common.

Biological Resources

Most of this area is forested below an elevation of about

1,800 to 2,000 feet (550 to 610 meters). White spruce, paper

birch, quaking aspen, and mixed forests cover most slopes.

White spruce forests and mixed white spruce-balsam poplar

forests are common on high flood plains and low terraces.

Black spruce woodlands are on steep north-facing slopes, high

stream terraces, and other sites with poor drainage and shallow

permafrost. Tussock-forming sedges commonly are dominant in

the ground layer. Low to tall willow and alder scrub is

extensive on low flood plains. Lightning-caused wildfires are

common, often burning many thousands of acres during a

single fire. Following wildfires, willow, shrub birch, and

ericaceous shrub scrub invade most sites until they are

eventually replaced by forest vegetation. With increasing

elevation, the forests and woodlands give way to low scrub

dominated by shrub birch and ericaceous shrubs. At even

higher elevations and on shallow soils on mountain slopes and

ridges, dwarf alpine scrub dominated by ericaceous shrub,
582 Major Land Resource Areas

dryas, and shrub birch is common. Many of these communities

have a considerable amount of lichen cover and bare ground.

Bedrock exposures with only lichens and scattered shrubs and

herbs in pockets of fine earth dominate the highest elevations

and ridges.

The common species of mammals in this area include moose,

caribou, black bear, brown bear, wolf, wolverine, and a variety

of small mammals. Dall sheep are in some of the higher

mountains. Golden eagles are common at the higher elevations,

and peregrine falcons nest in rocky canyons along many rivers.

The wetlands in the area provide high-quality habitat for

waterfowl, sandhill cranes, and other birds. Clear-water streams

support runs of salmon and are important habitat for arctic

grayling.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—28%

Forest—70%

Water—1%

Other—1%

Less than 1 percent of this area is used for hay, small grains,

potatoes, or other cool-season vegetables. Logging provides

important wood products for local use and export. Extractable

minerals, particularly gold and silver, occur in certain areas.

Mining in this area and in the adjacent Interior Alaska

Lowlands (MLRA 229) helped to support settlement and

development in the area. Less than 1 percent of the area is

urban. Urban development near Fairbanks and wild-land

recreation, primarily hunting for moose and other game, are

significant land uses. The Alaska road system penetrates much

of the area and provides good access for recreational activities.

Subsistence hunting, fishing, and gathering provide food and a

variety of other resources to local residents.

The major soil resource concerns are erosion of the shallow

soils on uplands and disturbance of the fragile permafrostaffected soils. Disturbance of the insulating organic material at

the surface results in thawing of the upper soil layers. This

thawing can result in ponding, soil subsidence, erosion, and

disruption of surface drainage. All management activities

should include protection of the organic surface material and

the thermal balance of the soils. 

Figure 232-1: Location of MLRA 232 in Land Resource Region X1.

232—Yukon Flats Lowlands

This area is in the Interior Region of Alaska and includes the

broad expanse of lowlands and low hills adjacent to the middle

reaches of the Yukon River, known locally as the Yukon Flats

(fig. 232-1). The area makes up about 12,785 square miles

(33,130 square kilometers). It is not accessible by road, is

mostly undeveloped wild land, and is sparsely populated. A

number of villages are in scattered areas along the Yukon River

and other major rivers. The largest of these villages are Ft.

Yukon, Venetie, and Stevens Village. Many fishing and hunting

camps, which are occupied seasonally by local residents, are

along the rivers. Part of the Yukon Flats National Wildlife

Refuge is in this area.

Physiography

This area lies within the Northern Uplands and Lowlands

Province of the Intermontane Uplands and Lowlands System.

The area consists primarily of a complex of nearly level to

undulating, marshy stream terraces and flood plains adjacent to

the Yukon River. Thousands of lakes, ponds, and

interconnecting wetlands fill depressions, shallow basins, and

abandoned river channels across the stream terraces. Floodplain features include multiple channels and islands, meander

scars, oxbow lakes, sloughs, and low escarpments. The water in

the lakes and wetlands is maintained by the yearly flooding

associated with spring breakup of ice on the Yukon River and

its tributaries. Strongly sloping to rolling uplands surround the

lowlands. These uplands, which consist of elongated footslopes

and coalescing alluvial fans, are at the base of the hills and

mountains of the Interior Alaska Highlands (MLRA 231).

Elevation ranges from about 300 feet (90 meters) to about

1,000 feet (305 meters).

The only Hydrologic Unit Area (identified by a four-digit

number) that makes up this MLRA is Yukon (1903). Surface
of the United States 583

water in all of the area drains into the Yukon River and the

Bering Sea. On the Yukon Flats, the major tributaries of the

Yukon River are the Porcupine, Sheenjek, Black, and

Chandalar Rivers. Lakes make up approximately 20 percent of

the area.

This area is in the zone of discontinuous permafrost.

Permafrost commonly is close to the surface in areas of the finer

textured sediments on plains, stream terraces, and the more

gently sloping footslopes and hills. Isolated masses of ground

ice occur in thick deposits of loess on terraces and the lower

side slopes of hills. Permafrost generally does not occur on

flood plains and near lakes and other water bodies.

Geology

This area is a broad intermontane tectonic basin filled with

Quaternary and earlier glaciofluvial and fluvial sediments. In

the central part of the basin, the glaciofluvial and fluvial

deposits overlie lacustrine sediments. Unconsolidated

sediments are estimated to be 300 to 400 feet (90 to 120 meters)

or more thick near the center of the basin. Along the edge of the

basin, much of the landscape is mantled with a thick layer of

silty loess of Pleistocene and Holocene age. Sand dunes cover

some areas. Fluvial and eolian sediments continue to be

deposited today. The underlying bedrock geology is

completely buried by unconsolidated sediments.

Climate

The average annual precipitation ranges from about 6 inches

(150 millimeters) in the central basin to 15 inches (380

millimeters) along the boundary with the surrounding

highlands. The maximum precipitation occurs in late summer,

mainly as a result of thunderstorms. The average annual

snowfall is about 45 to 55 inches (115 to 140 centimeters).

Short, warm summers and long, very cold winters characterize

the subarctic continental climate of the area. The surrounding

hills and mountains of this MLRA partially isolate it from

weather systems affecting other interior lowlands. As a result,

temperatures are generally warmer in summer and colder in

winter than is characteristic in other areas of comparable

latitude. The average annual temperature ranges from about 20

to 25 degrees F (-7 to -4 degrees C). The freeze-free period

averages 70 to 120 days. The temperature usually remains

above freezing from early June through late August.

Water

There are very limited withdrawals of freshwater for use in

this sparsely populated MLRA. Most of the communities in the

area are along the major rivers or lakes. Because of its chemical

quality, the surface water in the area generally is suitable for all

uses, but the rivers are frozen for much of the year or flow little

during winter. Also, the rivers are typically fed by glacial

meltwater, which carries high loads of suspended sediment. If

surface water is available, treatment for removal of the

suspended sediment would normally be required. For these

reasons, most of the water used for domestic supply in this area

is probably obtained from private wells.

Small communities and rural landowners probably obtain

ground water from the unconsolidated sediments in river

valleys (alluvium or glacial outwash). There are typically no

test data available on ground water in sparsely populated areas.

These aquifers are open to the surface, so they are highly

susceptible to contamination from surface activities. Septic

systems, landfills, and leaking fuel storage tanks are all

possible sources of contamination.

Soils

The dominant soil orders in this MLRA are Gelisols,

Inceptisols, and Entisols. The soils in the area have a subgelic

soil temperature class or a cryic soil temperature regime, an

aquic or udic soil moisture regime, and mixed mineralogy.

Aquiturbels and Histoturbels formed in loamy, sandy, and

gravelly alluvial deposits on nearly level stream terraces and in

silty loess over loamy slope alluvium on elongated footslopes.

Histoturbels have a moderately thick organic surface layer over

mineral material. Fibristels and Hemistels in abandoned

channels and depressions on stream terraces and on the margins

of lakes formed in thick layers of organic material. The Gelisols

are shallow or moderately deep to permafrost and are poorly

drained or very poorly drained. Wildfires disturb the insulating

organic material at the surface, lowering the permafrost layer

and eliminating perched water tables from some Gelisols.

Depending on the frequency of the fires, landform position, and

particle size, these soils may or may not revert back to Gelisols.

Eutrocryepts, Dystrocryepts, and Cryaquepts on nearly level

stream terraces, rolling uplands, and bluffs along the major river

channels formed in a moderately thick or thick layer of silty

loess over alluvial material. Some of these soils formed in

calcareous loess. Cryorthents and Cryofluvents on flood plains

and low stream terraces formed in loamy, sandy, and gravelly

alluvium. These soils range from very poorly drained to

excessively drained. Very poorly drained Cryofibrists and

Cryohemists along lake margins and in abandoned channels

and depressions on stream terraces formed in thick layers of

organic material.

Miscellaneous (nonsoil) areas make up about 20 percent of

this MLRA. The most common miscellaneous areas are

riverwash and water.

Biological Resources

The productive, well drained soils on uplands in this area

have white spruce, paper birch, quaking aspen, and mixed
584 Major Land Resource Areas

white spruce-paper birch-quaking aspen forests. Balsam poplar

and mixed white spruce-hardwood forests are on high flood

plains and low stream terraces. Stunted black spruce and white

spruce woodland of low productivity occurs on high stream

terraces and on cold, wet sites with shallow permafrost.

Tussock-forming sedges and mosses commonly are dominant in

the ground layer. Paper birch and, in places, tamarack occur in

association with spruce on permafrost-affected flats. Lightningcaused wildfires are common, often burning many thousands of

acres during a single fire. Following wildfires, willow, shrub

birch, and ericaceous shrub scrub invade most sites until they

are eventually replaced by forest vegetation. On all forest and

woodland sites, post-fire succession leads to a relatively rapid

accumulation of organic matter and moss on the surface. This

accumulation results in a decrease in soil temperature, biologic

activity, and nutrient availability and a gradual decrease in site

productivity. Tall and low scrub dominated by willow and alder

is common on low flood plains. The wettest sites dominantly

support tall to low alder and willow scrub, sedge-shrub

meadows, sedge meadows, and sedge-moss bog meadows.

The common species of mammals in the area are moose,

black bear, brown bear, wolf, caribou, wolverine, lynx, and a

variety of small mammals. The wetlands in the area provide

high-quality nesting habitat for tundra swans and a wide

variety of geese and ducks. Sandhill cranes and a variety of

raptors, grouse, and passerine birds inhabit the area. The

important fish in the rivers and lakes include salmon, arctic

grayling, whitefish, northern pike, blackfish, and burbot.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—8%

Forest—72%

Water—20%

Most of this area still supports natural vegetation and is used

primarily for subsistence hunting, fishing, and gathering by

local residents. Forests accessible from the villages provide

timber for local use. People from outside the MLRA use the

area for hunting and other kinds of wild-land recreation.

The major soil resource concern is flooding. Most

communities are in areas on the banks of the major rivers and

streams where flooding is a severe hazard. The flooding is

associated with spring snowmelt and runoff from the adjacent

mountains, with ice jamming on rivers during periods of

breakup, and occasionally with high-intensity summer

thunderstorms. On permafrost-affected soils, disturbance of the

insulating organic material at the surface results in thawing of

the upper soil layers. This thawing can result in ponding, soil

subsidence, erosion, and disruption of surface drainage. All

management activities should include protection of the

organic surface material and the thermal balance of the

soils. 

Figure 233-1: Location of MLRA 233 in Land Resource Region X1.

233—Upper Kobuk and Koyukuk Hills

and Valleys

This area is in the Interior Region of Alaska and includes

nearly level lowlands, rolling uplands, and isolated hills and

low mountains along the upper Kobuk River from

approximately its confluence with the Pau River east to the

Kanuti Flats along the middle Koyukuk River (fig. 233-1). The

area makes up about 12,910 square miles (33,455 square

kilometers). It is primarily undeveloped wild land and is

sparsely populated. The principal communities are the villages

of Kobuk in the western part of the area and Bettles, Alatna, and

Allakaket in the eastern part. A major part of Gates of the Arctic

National Park and Preserve and the Kanuti National Wildlife

Refuge are in this area.

Physiography

This area lies within the Western Alaska Province of the

Intermontane Uplands and Lowlands System. The area is in

broad, nearly level river valleys, in shallow basins, and on

rolling uplands separated by isolated hills and low, rounded

mountains. In the river valleys, nearly level flood plains and

stream terraces gradually give rise to gently sloping to

moderately steep slopes leading to the hills and mountains.

Extensive, nearly level to undulating basins are on the Pau

River Flats between the eastern Zane and Lockwood Hills, on

the Kanuti Flats between the Kanuti and Koyukuk Rivers, and
of the United States 585

along the middle reaches of the Hogatza River. Shallow basins

and depressions on stream terraces are dotted with hundreds of

lakes and interconnecting wetlands. Elevation ranges from

about 150 feet (45 meters) in the western part of the area, at the

confluence of the Kobuk and Mauneluk Rivers, to 4,765 feet

(1,453 meters) at the summit of Fritts Mountain, in the

Angaycuham Mountains.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Yukon (1903), 72 percent, and Northwest Alaska (1902), 28

percent. Surface water in the western third of this MLRA drains

into the Kobuk River and eventually into Kotzebue Sound and

the Chukchi Sea. The major tributaries of the Kobuk River are

the Reed, Beaver, Mauneluk, and Pau Rivers. Surface water in

the the eastern part of the MLRA drains into the Koyukuk

River and eventually into the Yukon River and the Bering Sea.

The major tributaries of the Koyukuk River are the Alatna,

John, and Kanuti Rivers. The area has a complex of ponds and

small lakes in basins and on stream terraces. Also, there are a

number of large lakes within and on the edge of the area. The

principal lakes are Walker Lake, Nutuvukti Lake, Naruak Lake,

and Lake Shelby. Lakes make up about 5 percent of the area.

This area is in the zone of discontinuous permafrost.

Permafrost is commonly close to the surface in areas of the finer

textured sediments throughout the MLRA. Isolated masses of

ground ice occur on terraces and the lower side slopes of hills.

Permafrost generally does not occur on flood plains or on steep

south-facing slopes. Periglacial features, such as pingos,

thermokarst pits and mounds, ice-wedge polygons, and earth

hummocks, are on the lower slopes and in upland valleys.

Geology

The northern part of this area was covered repeatedly by

Pleistocene glaciers originating in the Brooks Range to the

north. Slightly modified to highly modified moraines and drift

cover many of the rolling uplands. Glacial ice flowed over most

of the hills and low mountains, removing existing deposits and

leaving a thin layer of glacial deposits. Today, the lower

mountain slopes, hills, and valley bottoms are covered with a

variety of material, including glacial drift, colluvium, slope

alluvium, fluvial deposits, and silty loess. In the southern part

of the area, basins and valleys are filled with Quaternary

glaciofluvial and fluvial deposits. Hills and upland slopes are

covered with bedrock colluvium and slope alluvium, which are

mantled with loess in places. The bedrock geology underlying

much of the area consists dominantly of Permian through lower

Cretaceous stratified sedimentary and volcanic rocks.

Climate

The average annual precipitation ranges from 10 to 20

inches (255 to 510 millimeters) on valley bottoms and in basins

and from 20 to 40 inches (510 to 1,015 millimeters) at the

higher elevations in the hills and mountains. Most of the

precipitation falls as rain between May and September. Short,

warm summers and long, cold winters characterize the subarctic

continental climate of the area. The average annual snowfall

ranges from about 65 to 80 inches (165 to 205 centimeters).

The average annual temperature is about 20 to 22 degrees F (-7

to -6 degrees C). The freeze-free period ranges from less than 30

days to about 90 days. Normally, the temperature remains

above freezing from mid-June through August in river valleys

and basins.

Water

There are very limited withdrawals of freshwater for use in

this sparsely populated MLRA. Most of the communities in the

area are along the major rivers or lakes. Because of its chemical

quality, the surface water in the area generally is suitable for all

uses, but the rivers are frozen for much of the year or flow little

during winter. Also, the rivers are typically fed by glacial

meltwater, which carries high loads of suspended sediment. If

surface water is available, treatment for removal of the

suspended sediment would normally be required. For these

reasons, most of the water used for domestic supply in this area

is probably obtained from private wells.

Small communities and rural landowners probably obtain

ground water from bedrock aquifers or from the unconsolidated

sediments in river valleys (alluvium or glacial outwash). There

are typically no test data available on ground water in sparsely

populated areas. The unconsolidated sediments aquifer is open

to the surface, so it is highly susceptible to contamination from

surface activities. Septic systems, landfills, and leaking fuel

storage tanks are all possible sources of contamination.

Soils

The dominant soil orders in this MLRA are Gelisols,

Inceptisols, and Entisols. The soils in the area have a subgelic

soil temperature class or a cryic soil temperature regime, an

aquic or udic soil moisture regime, and mixed mineralogy.

Aquiturbels and Haploturbels on stream terraces, hills, and

upland slopes formed in silty loess or alluvium over very

gravelly loamy alluvium and glacial drift. Hemistels are in

areas of peat plateaus, palsas, and depressions on hills and

upland slopes. Fibristels are in sloughs and depressions on

stream terraces and on the margins of lakes. The Gelisols

generally are shallow or moderately deep to permafrost and are

poorly drained or very poorly drained. Wildfires can disturb the

insulating organic material at the surface, lowering the

permafrost layer, eliminating perched water tables from

Gelisols, and thus changing the classification. Depending on

the frequency of the fires, landform position, and particle size,

the soils may or may not revert back to Gelisols. Eutrocryepts,

Dystrocryepts, and Cryorthents on upland slopes, shoulders,

and the crests of hills, and occasionally on stream terraces,
586 Major Land Resource Areas

formed in silty loess over very gravelly loamy colluvium,

glacial till, and alluvium. These soils do not have permafrost

within their soil profile, are deep, and are moderately well

drained to excessively drained. Cryofluvents and Cryorthents

on flood plains formed in stratified loamy, sandy, and very

gravelly alluvium. These soils range from very poorly drained

to excessively drained.

Miscellaneous (nonsoil) areas make up about 8 percent of

this MLRA. The most common miscellaneous areas are rock

outcrop and water.

Biological Resources

Most of this MLRA is in areas of open black spruce forests

and black spruce woodland. Open white spruce forests and tall

alder scrub with common white spruce are on active flood

plains and steep mountain slopes with a southern aspect. On the

drier sites and in areas of recent burns, paper birch and quaking

aspen occur along with black spruce. Lightning-caused

wildfires are common, often burning many thousands of acres

during a single fire. Following wildfires, willow, shrub birch,

and ericaceous shrub scrub invade most sites until they are

eventually replaced by forest vegetation. On all forest and

woodland sites, post-fire succession leads to a relatively rapid

accumulation of organic matter and mosses on the surface. This

accumulation results in a decrease in soil temperature, biologic

activity, and nutrient availability and a gradual decrease in site

productivity. Nonforest vegetation includes low to tall willow,

shrub birch, and ericaceous shrub scrub in areas of peat, in

drainageways, and in areas above an elevation of about 2,000

feet (610 meters). Moist sedge meadows, commonly with

tussock-forming sedges, are on nearly level uplands. Wet

sedge meadows and sedge-moss bog meadows are along the

margins of lakes and on continuously ponded sites. Low to tall

willow scrub with common balsam poplar is on low flood

plains.

The common species of mammals in the area include brown

bear, black bear, caribou, moose, wolf, beaver, and a variety of

small mammals. The ponds and wetlands in the area provide

high-quality habitat for tundra swans and other waterfowl. Bald

eagles are common along most of the rivers. Arctic grayling,

burbot, northern pike, sheefish, and whitefish are in the rivers

and lakes in the area.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—16%

Forest—76%

Water—5%

Other—3%

Most of this area still supports natural vegetation and is used

primarily for subsistence hunting, fishing, and gathering by

local residents. The major soil resource concern is disturbance

of the fragile permafrost-affected soils. Disturbance of the

insulating organic material at the surface results in thawing of

the upper soil layers. This thawing can result in ponding, soil

subsidence, erosion, and disruption of surface drainage. All

management activities should include protection of the organic

surface material and the thermal balance of the soils. 

Figure 234-1: Location of MLRA 234 in Land Resource Region X1.

234—Interior Brooks Range Mountains

This area is in the Interior Region of Alaska and includes the

high mountains and valleys on the southern side of the Brooks

Range (fig. 234-1). The area makes up about 19,245 square

miles (49,875 square kilometers). It is almost entirely remote

wild land and is sparsely populated. The Dalton Highway

(known locally as the Haul Road) bisects the Brooks Range at

Atigun Pass. Anaktuvuk Pass and Arctic Village are two remote

villages in this MLRA. Coldfoot, Wiseman, and Dietrich Camp,

along the Dalton Highway, are the only other permanent

settlements. Extensive portions of the Gates of the Arctic

National Park and Preserve and the Arctic National Wildlife

Refuge are in this area.

Physiography

This area lies within the Arctic Mountains Province of the

Rocky Mountain System. The Brooks Range is the most
of the United States 587

northerly extension of the Rocky Mountains. The terrain

consists dominantly of steep, rugged, high mountains and

narrow, high-gradient valleys. At the upper elevations, the

mountains are generally rocky and have sharp ridges. Small

glaciers occur in some areas at the higher elevations. The lower

mountain slopes are characterized by coalescing alluvial and

colluvial fans and steep footslopes, many of which extend

down and into the stream channels. Narrow, discontinuous

flood plains are in the wider, more gently sloping parts of the

valleys. The bottoms of valleys along the larger rivers and

streams have nearly level flood plains and stream terraces.

Elevation ranges from about 1,600 feet (490 meters) to nearly

8,000 feet (2,440 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Yukon (1903), 90 percent; Northwest Alaska (1902), 9 percent;

and Arctic Slope (1901), 1 percent. Surface water in this MLRA

drains entirely into the Yukon River system and the Bering Sea.

The major rivers that have their headwaters in the area are the

Sheenjek, Chandalar, Koyukuk, John, and Alatna Rivers. Lakes

make up less than 5 percent of the area.

This area is in the zone of discontinuous permafrost.

Permafrost generally is close to the surface only in areas of the

finer textured sediments on stream terraces and in swales on

hills and footslopes. Periglacial features include gelifluction

lobes, polygons, and stripes.

Geology

During the early and middle Pleistocene epoch, glacial ice

buried most of this area. By the late Pleistocene epoch, only the

highest valleys and mountains were still glaciated. Most glacial

deposits have eroded away or have been buried by mountain

colluvium and slope alluvium, which accumulated during the

Holocene epoch across about 95 percent of the landscape.

Slightly modified to highly modified glacial moraines, drift,

and outwash deposits occur in some areas on the lower

mountain slopes and in valleys at the lower elevations. Recent

and Pleistocene fluvial deposits are on flood plains, stream

terraces, and alluvial fans. The underlying bedrock geology

consists almost entirely of stratified sedimentary rocks of

Paleozoic and Precambrian age. The eastern part of the area

includes Paleozoic and early Jurassic volcanic and igneous

rocks.

Climate

The average annual precipitation ranges from about 10 to 15

inches (255 to 380 millimeters) on valley bottoms at the lower

elevations and from 20 to 30 inches (510 to 760 millimeters) at

the highest elevations. The average annual snowfall is about 60

to 100 inches (150 to 255 centimeters). Short, cool summers

and long, cold winters characterize the subarctic continental

climate of the area. Strong winds are common at the higher

elevations in mountain valleys. The average annual

temperature ranges from 8 to 16 degrees F (-13 to -9 degrees C).

The length of the freeze-free period is not known. Freezing

temperatures can occur throughout the year, and extended

periods of extreme cold are common during most winters.

Water

There are very limited withdrawals of freshwater for use in

this sparsely populated MLRA. The few communities in the

area are along the Haul Road. Because of its chemical quality,

the surface water in the area generally is suitable for all uses,

but the rivers are frozen for much of the year or flow little

during winter. Also, the rivers are typically fed by glacial

meltwater, which carries high loads of suspended sediment. If

surface water is available, treatment for removal of the

suspended sediment would normally be required. For these

reasons, most of the water used for domestic supply in this area

is probably obtained from private wells.

Small communities, rural landowners, and miners probably

obtain ground water from the bedrock aquifer or the

unconsolidated sediments in river valleys (alluvium or glacial

outwash). There are typically no test data available on ground

water in sparsely populated areas. The unconsolidated

sediments aquifer is open to the surface, so it is highly

susceptible to contamination from surface activities. Septic

systems, landfills, leaking fuel storage tanks, and mine waste

are all possible sources of contamination.

Soils

The dominant soil orders in this MLRA are Gelisols,

Entisols, and Inceptisols. The soils in the area have a subgelic

soil temperature class or a cryic soil temperature regime, a udic

or aquic soil moisture regime, and mixed mineralogy.

Histoturbels and Aquiturbels on the lower mountain slopes,

elongated footslopes, and stream terraces formed in loamy to

cobbly colluvium, slope alluvium, and fluvial deposits. Many

of these soils have a mineral surface layer of silty loess.

Histoturbels have a moderately thick surface layer of organic

material. Turbels, Gelepts, and Gelolls on mountain slopes,

hillslopes, ridges, and fans formed in loamy and gravelly

colluvium over fractured bedrock and loamy glacial drift.

Fibristels and Hemistels in depressions and on the margins of

lakes formed in thick layers of organic material. The Gelisols

are shallow or moderately deep to permafrost and range from

somewhat poorly drained to very poorly drained. Wildfires can

disturb the insulating organic material at the surface, lowering

the permafrost layer, eliminating perched water tables from

Gelisols, and thus changing the classification. Depending on

the frequency of the fires, landform position, and particle size,

the soils may or may not revert back to Gelisols. Cryorthents,

Eutrocryepts, and Dystrocryepts on south-facing slopes and

ridges in the foothills and on the bottoms of narrow, steep
588

valleys formed in loamy to very gravelly colluvium, fractured

bedrock residuum, and glacial drift. Cryofluvents and

Cryorthents on flood plains and natural levees along streams

formed in loamy, sandy, and gravelly alluvium. Inceptisols and

Entisols do not have permafrost within their soil profile and

range from excessively drained to poorly drained.

Miscellaneous (nonsoil) areas make up about 63 percent of

this MLRA. The most common miscellaneous areas are rock

outcrop, rubble land, riverwash, and glaciers.

Biological Resources

Because of the shallow soils, strong winds, and harsh

climate, vegetation is sparse in this area. It generally is limited

to valleys and the lower mountain slopes. Dwarf scrub

communities on mountain slopes and ridges are dominated by

black crowberry, ericaceous shrubs, dryas, and dwarf willow. On

shallow, rocky soils and exposed sites, lichens and scattered

herbs dominate the ground layer. Bare soil and exposed

bedrock generally are extensive. On the more mesic sites,

sedges, forbs, and mosses cover most of the surface. The lower

elevations and the deeper soils in basins and on terraces are

dominated by white spruce and mixed spruce-hardwood forests

and woodland, low willow and ericaceous shrub scrub, and

mesic graminoid herbaceous communities. Black spruce

woodlands, commonly with extensive areas of tussock-forming

sedges, are common on high stream terraces and mountain

footslopes. Depressions, drainageways, and other saturated

areas have wet sedge meadows and wet sedge-moss meadows.

Low and tall willow scrub is dominant on flood plains.

The most common species of mammals in the area include

brown bear, black bear, wolf, caribou, and Dall sheep. The

smaller mammals include marmot, red fox, arctic fox,

wolverine, ground squirrel, lemming, and pika. The most

common raptors are golden eagles, marsh hawks, and snowy

owls in many areas.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—24%

Forest—13%

Water—5%

Other—58%

Most of this area still supports natural vegetation and is used

primarily for subsistence hunting, fishing, and gathering by

local residents. The area also is widely used for sport hunting

and other kinds of wild-land recreation. Most visitors are served

by air taxi, guiding, and outfitting companies operating out of

the major Alaska communities. Mineral resources, including

gold, silver, and copper, have been mined in a number of areas.

Sand and gravel pits are along the Dalton Highway. The major

resource concerns in this area are maintaining the protective

plant cover and maintaining the thermal balance of permafrostaffected soils. 
589

Figure X2-1: Location of Land Resource Region X2.

X2—Western Alaska

This region is in the western part of Alaska (fig. X2-1). It is

near the Bering Sea from the Alaska Peninsula and Bristol Bay

lowlands to the southern Seward Peninsula. The region

includes the northern Bering Sea islands. It makes up 91,300

square miles (236,585 square kilometers).

This region consists of diverse landforms, including

mountains, hills, coastal plains, outwash plains, stream terraces,

volcanic cinder cones, and dunes. Elevation ranges from sea

level to about 7,000 feet (2,135 meters). The Ahklun, Kilbuck,

and Alaska Peninsula Mountains are generally steep and

rugged. Rolling hills, low mountains, and broad valleys

characterize the Nulato Hills, the Seward Peninsula, and the

northern Bering Sea islands. The rest of the region consists of

coastal lowlands and rolling uplands. Lakes and

interconnecting wetlands cover as much as 80 percent of the

coastal lowlands. Permafrost is discontinuous across the region.

It is prevalent on coastal plains, terraces, and footslopes, but it

normally does not occur on steep slopes or on flood plains.

Patterned ground and gelifluction lobes are common in many

of the permafrost-affected areas.

The climate ranges from maritime near the coast to subarctic

continental away from the coast and at the higher elevations. In

the northern part of the region, the winter climate becomes

more continental as the icepack forms in the Bering Sea.

Summers are short and warm, and winters are long and cold. In

summer cloudy conditions are common along the coast. The

annual precipitation throughout the region ranges from about

13 to 80 inches (330 to 2,030 millimeters). The amount of

precipitation is lowest in lowland areas and the Nulato Hills

and increases markedly at the higher elevations of the Ahklun

and Alaska Peninsula Mountains. The average annual

temperature ranges from 25 to 36 degrees F (-4 to 2 degrees C).

It varies most in the mountainous areas. Frost may occur in any

month. Strong winds are common, especially in winter. Snow

covers the ground for approximately 7 to 9 months each year.

The total withdrawals of freshwater in this region average

just under 1 million gallons per day (3.5 million liters per day).

About 67 percent is from surface water sources, and 33 percent

is from ground water sources. About 55 percent of the water is

used for public supply in the coastal towns and communities.

The rest is used mainly in mines and in some small-scale

seafood-processing plants.
590 Major Land Resource Areas

Figure X2-2: Reindeer grazing in an area of Land Resource Region X2.

Gelisols, which have permafrost in their profile, occur

throughout the region and make up about 45 percent of the soil

types. Orthels and Turbels are on level to sloping coastal plains

and terraces as well as on footslopes and in swales in the hills

and mountains. Mollorthels and Molliturbels are typical in the

limestone uplands of the northern Bering Sea islands. Histels

are in most of the depressions throughout the region. Coarse

textured Gelepts and Gelolls with a cryic soil temperature

regime are on steep slopes in the mountainous areas. Well

drained Cryepts and Cryolls are on moraines and outwash

plains. Cryands are in areas where volcanic ash and loess

mantle older landforms and in areas along the flanks of cinder

cones. Well drained Cryods are in scattered areas on uplands

throughout the region. Fluvents are on flood plains and levees,

and Psamments are in areas of dunes.

Arctic tundra and alpine tundra dominated by low and

dwarf scrub and herbaceous communities are dominant

throughout most of this region. Tussock tundra occurs across

broad expanses of uplands. Wet sedge and sedge-grass

meadows, sedge-moss meadows, and sedge-shrub meadows are

on coastal wetlands and in poorly drained areas in

drainageways. Of limited extent on valley bottoms, on well

drained soils at the lower elevations, are open forests and

woodland of white and black spruce and, in places, paper birch

and balsam poplar. Low and tall scrub, dominated by alder and

willow, is common on mid-mountain slopes and flood plains.

Land use throughout the region includes reindeer herding

(fig. X2-2), mining, wildlife habitat, and subsistence hunting,

fishing, and gathering. 
of the United States 591

Figure 235-1: Location of MLRA 235 in Land Resource Region X2.

235—Northern Alaska Peninsula

Mountains

This area is in the Western Region of Alaska and includes

the northwest-facing slopes of the southern Aleutian Mountains

(fig. 235-1). It makes up about 5,715 square miles (14,815

square kilometers). It is mostly undeveloped wild land and is

sparsely populated. The only permanent settlements in the area

are several small villages and remote recreational lodges. Parts

of the Katmai National Park and Preserve, the Alaska Peninsula

National Wildlife Refuge, and the Becharof National Wildlife

Refuge are in this area.

Physiography

This area lies within the Alaska-Aleutian Province of the

Pacific Mountains System. The terrain consists primarily of

rugged, low to moderately high mountains deeply dissected

with narrow, high-gradient valleys. On the highest peaks in the

area, glaciers and small ice fields are common. Glaciers and

permanent ice and snow make up about 2 percent of the area. In

steep, narrow valleys, coalescing fans, footslopes, and small

stream channels are contiguous downslope. At the lower

elevations, along the boundary with the Bristol Bay-Northern

Alaska Peninsula Lowlands (MLRA 236), flood plains and

stream terraces are common on valley bottoms. Elevation

ranges from about 14 feet (4 meters) along the shoreline of

Becharof Lake to more than 7,000 feet (2,135 meters) at the

summits of Mt. Veniaminof and Mt. Douglas.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Southwest Alaska (1904), 97 percent, and South Central Alaska

(1905), 3 percent. Surface water in this MLRA drains into the

Bristol Bay-Northern Alaska Peninsula Lowlands (MLRA 236)

via numerous short, high-gradient streams and creeks that

originate in the high basins and glaciers of the mountains. The

headwaters of the Kvichak, Naknek, King Salmon, and Egegik

Rivers originate in this MLRA. Lakes make up about 3 percent

of the area.

Geology

Except for the highest peaks and steep ridges at the higher

elevations, the entire area was covered by glacial ice during the

late Pleistocene epoch. During the Holocene epoch, glacial

deposits across much of the area eroded away or were buried by

colluvium and slope alluvium. Mountain colluvium and

alluvium cover about 50 percent of the present landscape.

Slightly modified glacial moraines and drift and scattered areas

of glaciofluvial deposits are extensive on the lower mountain

slopes and in valleys at the lower elevations. Volcanic activity

on Mt. Katmai and other volcanoes on the lower Alaska

Peninsula and the Aleutian Islands has deposited a layer of

volcanic ash across much of the landscape at the lower

elevations. The dominant geologic formations underlying most

of the area are upper Jurassic and some Cretaceous and lower

Tertiary stratified sedimentary rocks. Jurassic intrusive rocks

and Tertiary and Quaternary volcanic rocks are common

locally, particularly in the vicinity of volcanoes.

Climate

The average annual precipitation ranges from 30 inches (760

millimeters) at the lower elevations in this area to more than

100 inches (2,540 millimeters) at the higher elevations. The

climate in the area is influenced by the maritime conditions of

Bristol Bay and the Bering Sea in the western part of the area,

by spillover effects from the North Pacific to the southeastern

part of the area, and by the orographic effects of the rugged

mountainous environment. Summers are short, cool, and

frequently cloudy and rainy. Windy conditions are common

throughout the year. Winters are long and cold, generally with

deep snow. The average annual snowfall is about 50 to 200

inches (125 to 510 centimeters). The average annual

temperature and the length of the freeze-free period are not

known. Freezing temperatures are likely to occur during any

month of the year, particularly at the higher elevations.
592 Major Land Resource Areas

Water

There are very limited withdrawals of freshwater for use in

this sparsely populated MLRA. The few communities in the

area and the recreational lodges are generally on the coast.

Because of its chemical quality, the surface water in the area

generally is suitable for all uses, but the rivers are probably

frozen for much of the year or flow little during winter. Also, the

rivers are typically fed by glacial meltwater, which carries high

loads of suspended sediment. If surface water is available,

treatment for removal of the suspended sediment would

normally be required. For these reasons, most of the water used

for domestic supply in this area is probably obtained from

private wells.

Small communities and rural landowners probably obtain

ground water primarily from bedrock aquifers. Some wells may

be in unconsolidated sediments in river valleys (alluvium or

glacial outwash). There are typically no test data available on

ground water in sparsely populated areas. If these aquifers are

close to the surface, they are highly susceptible to

contamination from surface activities. Septic systems, landfills,

and leaking fuel storage tanks are all possible sources of

contamination.

Soils

The dominant soil orders in this MLRA are Andisols and

Histosols. The soils in the area have a cryic soil temperature

regime or a subgelic soil temperature class, a udic or aquic soil

moisture regime, and amorphic or mixed mineralogy.

Haplocryands on the lower mountain slopes, fans, and

stream terraces formed in a moderately thick or thick layer of

silty volcanic ash over various materials, including loamy,

gravelly, and cobbly colluvium, glacial drift, and slope

alluvium. Haplocryands on the upper mountain slopes and

ridges formed in a thin or moderately thick layer of volcanic

ash over cobbly colluvium and slope alluvium over bedrock

residuum. These soils generally are well drained. Cryofibrists

on valley bottoms and in depressions formed in thick deposits

of organic material. These soils are poorly drained or very

poorly drained.

Miscellaneous (nonsoil) areas make up about 43 percent of

this MLRA. The most common miscellaneous areas are

riverwash, rock outcrop, rubble land, and glaciers.

Biological Resources

The lower elevations in this area generally support tall scrub

dominated by alder and willow. Balsam poplar forests, with tall

shrub and herbaceous understory, are on flood plains and some

south-facing mountain slopes. With increasing elevation, tall

scrub rapidly gives way to low scrub dominated by willow,

ericaceous shrubs, and various graminoids and forbs.

Grasslands of bluejoint reedgrass are in scattered areas

throughout the scrub. At the highest elevations and on exposed

ridges and steep slopes where the soils are shallow over

bedrock, dwarf scrub is dominant. Crowberry, ericaceous

shrubs, willow, bryophytes, and lichens generally dominate

dwarf shrub communities. Poorly drained areas and areas of

peat support low scrub and sedge-grass meadows.

Some of the major species of mammals in the area are brown

bear, Dall sheep, moose, wolf, and coyote. Ptarmigan, American

golden plovers, golden eagles, and a wide variety of other birds

are common in many places.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—53%

Forest—4%

Water—3%

Other—40%

This area is mostly remote wild land and is used for

recreation. Most visitors are served by air taxi, guiding,

and outfitting companies operating out of the major Alaska

communities. Subsistence hunting, fishing, and gathering

provide food and a variety of other resources to local

residents. 

236—Bristol Bay-Northern Alaska

Peninsula Lowlands

This area is in the Western Region of Alaska and includes

the nearly level to rolling lowlands, uplands, and isolated hills

adjacent to Bristol Bay (fig. 236-1). The area makes up about

19,575 square miles (50,725 square kilometers). It is mostly

undeveloped wild land and is sparsely populated. The

principal communities are Dillingham, Naknek, and King

Salmon. Numerous other villages are in scattered areas

throughout the MLRA, primarily along the major rivers and the

shoreline of lakes. Parts of the Katmai and Aniakchak National

Parks and Preserves and the Alaska Peninsula, Becharof,

Togiak, and Alaska Maritime National Wildlife Refuges are in

this area.

Physiography

This area lies within the Western Alaska Province of the

Intermontane Uplands and Lowlands System. The terrain

consists dominantly of a broad expanse of gently sloping to

rolling plains and low- or moderate-relief hills bordered by

moderately sloping, elongated mountain footslopes.

Depressions and shallow basins on terraces and plains are

dotted with small and medium-size lakes and interconnecting

stream channels and wetlands. To the west, along the border
of the United States 593

Figure 236-1: Location of MLRA 236 in Land Resource Region X2.

with the Ahklun Mountains (MLRA 237), and to the east, along

the border with the Northern Alaska Peninsula Mountains

(MLRA 235), large lakes behind terminal moraines extend from

the mountain valleys out onto the plains. Narrow, low-gradient,

meandering flood plains and low stream terraces are along the

major rivers in the central part of the area. In the southwestern

part of the area, short, high-gradient rivers and streams

originating in the adjacent mountains have formed broad,

braided alluvial fans and flood plains. Isolated hills and

rounded, low-relief mountains are in scattered areas throughout

the inland part of the MLRA. Elevation ranges from sea level

along the coast of Bristol Bay to about 2,500 feet (760 meters)

in the mountains.

The only Hydrologic Unit Area (identified by a four-digit

number) that makes up this MLRA is Southwest Alaska (1904).

Surface water in this MLRA drains entirely into Bristol Bay.

The major rivers are the Egegik, Kvichak, Mulchatna, Naknek,

Nushagak, Ugasik, and Wood Rivers. Most of the rivers and

streams are meandering. The large lakes in the Aleutian Range

include Lake Grosvenor and Iliamna, Kukaklek, Nonvianuk,

Naknek, and Becharof Lakes. The Wood-Tikchik Lakes system

is in the western part of the area, along the Ahklun Mountains.

Lakes make up about 10 percent of the area.

This area is in the zone of discontinuous permafrost.

Permafrost generally is at a considerable depth below the

surface and occurs primarily in areas of the finer textured

sediments on stream terraces, rolling uplands, and gently

sloping footslopes. Isolated masses of ground ice occur in some

areas of glacial drift and other unconsolidated materials.

Permafrost generally does not occur on flood plains, near the

coast, or in the southern part of the area.

Geology

During the early to middle Pleistocene epoch, the entire area

was covered with glacial ice originating in the Aleutian Range

to the east and the Ahklun Mountains to the west. Little

glaciation remained by the late Pleistocene, except possibly in

the higher hills and foothills near the mountains. Today,

Pleistocene-age moraines, drift, and glaciofluvial deposits

cover approximately 60 percent of the area. Elsewhere, mixed

Holocene and Pleistocene fluvial and coastal deposits are

dominant. Interlayered alluvial and marine sediments occur on

the Nushagak Peninsula in the western part of the MLRA and in

coastal areas in the eastern and southern parts. Much of the area

has been mantled with a layer of silty volcanic ash and loess of

varying thickness from regional volcanoes and unvegetated

flood plains and outwash plains. The underlying bedrock

geology consists primarily of Tertiary and Quaternary stratified

sedimentary rocks. Tertiary volcanic rocks are of minor extent

in scattered areas near the Aleutian Mountains.

Climate

The average annual precipitation in this area is 13 to 50

inches (330 to 1,270 millimeters), generally increasing with

distance from the coast and with elevation. The climate of the

area is strongly maritime near the coast of Bristol Bay.

Continental weather systems from Interior Alaska probably

have a significant influence farther inland, particularly in the

winter. Summers are short and warm. Cloudy conditions and

rain are common in summer. Winters are long and cold. The

average annual snowfall is about 30 to 80 inches (75 to 205

centimeters). The average annual temperature ranges from 30 to

36 degrees F (-1 to 2 degrees C). The freeze-free period averages

about 70 to 125 days.

Water

There are very limited withdrawals of freshwater for use in

this sparsely populated MLRA. The only measurable

withdrawal is for seafood-processing plants (0.2 million

gallons, or 0.8 million liters, per day). Most of the communities

in the area are on the coast or along the major rivers and lakes.

Because of its chemical quality, the surface water in the area

generally is suitable for all uses, but the rivers are frozen for

much of the year or flow little during winter. Also, the rivers are

typically fed by glacial meltwater, which carries high loads of

suspended sediment. If surface water is available, treatment for

removal of the suspended sediment would normally be

required. For these reasons, most of the water used for domestic

supply in this area is probably obtained from private wells.
594 Major Land Resource Areas

Small communities and rural landowners probably obtain

ground water primarily from unconsolidated sediments in river

valleys (alluvium or glacial outwash). There are typically no

test data available on ground water in sparsely populated areas.

If these aquifers are close to the surface, they are highly

susceptible to contamination from surface activities. Septic

systems, landfills, and leaking fuel storage tanks are all

possible sources of contamination. The intrusion of seawater

can be a problem along the coast.

Soils

The dominant soils in this MLRA are Gelisols, Andisols, and

the andic subgroups of Spodosols, Histosols, Inceptisols, and

Entisols. The soils have a subgelic soil temperature class or a

cryic soil temperature regime, an aquic or udic soil moisture

regime, and mixed or amorphic mineralogy.

Histoturbels and Aquiturbels on stream terraces and plains

formed in loamy, sandy, and gravelly fluvial sediments. Many

of these soils have a thin or moderately thick mineral surface

layer of silty volcanic ash and loess. Fibristels, which are

generally in depressions and shallow basins, formed in thick

deposits of organic material. The Gelisols in the area are

shallow or moderately deep to permafrost and are poorly

drained or very poorly drained. Haplocryands, Haplocryods,

Humicryods, and Dystrocryepts on rolling uplands and

footslopes along the boundary with the adjacent mountains

formed in a moderately thick or thick layer of silty volcanic ash

over various glacial, fluvial, and colluvial sediments. Andisols

and Spodosols do not have permafrost within their soil profile

and generally are deep and moderately well drained or well

drained. Cryofluvents and Cryaquents on flood plains, low

stream terraces, and alluvial fans formed in stratified loamy,

sandy, and gravelly alluvium. These soils are deep and range

from poorly drained to excessively drained.

Miscellaneous (nonsoil) areas make up about 14 percent of

this MLRA. The most common miscellaneous areas are water,

riverwash (particularly in the southwestern part of the MLRA),

and beaches.

Biological Resources

The moderately well drained soils on plains and rolling

uplands in this MLRA generally support low and dwarf scrub

dominated by ericaceous shrubs and herbs and in many areas

by lichens and mosses. The somewhat poorly drained soils in

bogs and other areas of peat generally support low and dwarf

scrub dominated by shrub birch, ericaceous shrubs, tussockforming sedges, and a thick, continuous layer of mosses. Poorly

drained soils on lowlands, fens, and the margins of lakes are

vegetated with wet herbaceous communities, including sedge

marshes, sedge and sedge-moss meadows, and, near the coast,

halophytic sedge meadows. Balsam poplar and mixed balsam

poplar-white spruce forest communities, typically with an

understory of tall and low shrubs, are on flood plains along the

major rivers. Dwarf alpine scrub, lichens, and bare ground occur

on convex slopes and ridges at the higher elevations of isolated

hills and mountains.

The common species of mammals in the area include brown

bear, black bear, wolf, wolverine, caribou, moose, and a variety

of other furbearers. The lowlands have good-quality habitat for

waterfowl. Many species of migratory waterfowl use the

lowlands as staging and nesting areas. Nearly the entire

population of Pacific black brant, numbering 250,000, and

most of the world’s population of the emperor goose use the

coastal lagoons and wetlands in this area during their spring

and fall migrations. Canada goose, ducks, tundra swans, and

sandhill cranes also are common in the area. Many millions of

shore birds use the same habitats and flyways as the migrating

waterfowl. Most rivers and streams are important spawning

areas for salmon, which provide world-class sport fishing

during summer and fall for visitors and local residents. Many

streams and lakes support rainbow trout. Introduced northern

pike, a major predator of small salmon, other desirable fish, and

waterfowl, are in many of the lakes in the area.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—66%

Forest—20%

Water—10%

Other—4%

Commercial fishing in Bristol Bay and the Bering Sea is the

primary enterprise in this area. Most coastal communities

support a fleet of boats and related fishing facilities. Many also

have fish-processing plants. Less than 1 percent of the area is

urban. Most inland areas still support natural vegetation and

are used primarily for subsistence hunting, fishing, and

gathering by local residents. The Mulchatna caribou herd in the

area attracts subsistence and sport hunters from around Alaska

and elsewhere. Wilderness recreation and sport fishing are

increasingly popular in the area. Most visitors are served by air

taxi and guiding services out of Dillingham, King Salmon, and

other communities and by guest lodges in the area.

The major soil resource concern is disturbance of the fragile

permafrost-affected soils. Disturbance of the insulating organic

material at the surface results in thawing of the upper soil

layers. This thawing can result in ponding, soil subsidence,

erosion, and disruption of surface drainage. All management

activities should include protection of the organic surface

material and the thermal balance of the soils. 
of the United States 595

Figure 237-1: Location of MLRA 237 in Land Resource Region X2.

237—Ahklun Mountains

This area is in the Western Region of Alaska and includes

the mountains, hills, and valleys of the Ahklun and Kilbuck

Mountains (fig. 237-1). The area includes Hagemeister Island

and the Walrus Islands in Bristol Bay. It makes up about 14,555

square miles (37,715 square kilometers). It is primarily

undeveloped wild land and is sparsely populated. The principal

communities, which are mainly along the coast of Bristol Bay

and Kuskokwim Bay in the southwestern part of the area, are

Goodnews Bay, Manokotak, and Togiak. Parts of the Togiak,

Yukon Delta, and Alaska Maritime National Wildlife Refuges

are in this area.

Physiography

This area lies within the Ahklun Mountains Province of the

Intermontane Uplands and Lowlands System. The terrain

consists of steep, rugged, low mountains cut throughout with

narrow to broad valleys. Flood plains and terraces are common

at the lower elevations in the valleys along the larger rivers.

Alluvial and colluvial fans and steep mountain footslopes are

common features of the valleys throughout the area. Along the

coast, where the Togiak and Goodnews Rivers empty into the

Bering Sea, nearly level to rolling deltas are dotted with

numerous small lakes. To the east, along the border with the

Bristol Bay-Northern Alaska Peninsula Lowlands (MLRA 236),

are deep, east-west oriented, glacially carved valleys that

include the Wood-Tikchik Lakes. Elevation ranges from sea

level on the coast of the Bering Sea in the southern part of the

area to 4,658 feet (1,420 meters) at the summit of Mt. Oratia.

The only Hydrologic Unit Area (identified by a four-digit

number) that makes up this MLRA is Southwest Alaska (1904).

All of the surface water in this area drains into the Bering Sea

via numerous rivers emptying directly into the Bering Sea or

into the Wood-Tikchik Lakes to the east or the Kuskokwim

River to the north and west. The major rivers are the Goodnews,

Togiak, Kanektok, Osviak, Eek, and Arolik Rivers. Lakes make

up about 5 percent of the area.

This area is in the zone of discontinuous permafrost. Isolated

masses of permafrost are in areas of deep, unconsolidated

deposits in the mountains. On lowlands, permafrost occurs as

isolated masses primarily in areas of the finer textured

materials. It generally does not occur on flood plains and near

the coast.

Geology

Throughout the Pleistocene epoch, all of the Ahklun

Mountains were extensively glaciated, possibly except for the

highest peaks and the upper ridges. The Kilbuck Mountains

were unglaciated. Coastal lowlands were generally free of ice

by the late Pleistocene. During the Holocene epoch, colluvium

and slope alluvium accumulated across about 40 percent of the

area. Glacial moraines and drift still cover approximately 45

percent of the area, primarily on the lower mountain slopes,

valley bottoms, and coastal plains. Recent alluvial deposits are

on flood plains and on interlayered alluvial and marine

deposits on coastal lowlands. The bedrock geology underlying

most of the area is dominantly Jurassic and Cretaceous

stratified sedimentary rocks. Less common are Paleozoic

sedimentary rocks. Exposed volcanic intrusive rocks that

impart a ring-like structure to some of the isolated mountain

groups are in scattered areas throughout the MLRA. Volcanic

rocks are more common in the Kilbuck Mountains. The area is

cut by numerous northeast-trending faults.

Climate

The average annual precipitation is 20 to 30 inches (510 to

760 millimeters) at the lower elevations in this area and can

exceed 50 inches (1,270 millimeters) at the higher elevations.

The climate of the area is under both maritime and continental

influences, depending on the time of year and the proximity to

the coast of Bristol Bay and the Bering Sea. Orographic

influences also are likely important. Summers are short and

variable. Winters are long and cold. The average annual

snowfall ranges from about 80 to 200 inches (205 to 510

centimeters). The average annual temperature along the coast is
596 Major Land Resource Areas

about 33 degrees F (1 degree C). The length of the freeze-free

period along the coast averages 110 to 135 days.

Water

There are very limited withdrawals of freshwater for use in

this sparsely populated MLRA. Most of the communities in the

area are on the coast. Because of its chemical quality, the

surface water in the area generally is suitable for all uses, but

the rivers are frozen for much of the year or flow little during

winter. Also, the rivers are typically fed by glacial meltwater,

which carries high loads of suspended sediment. If surface water

is available, treatment for removal of the suspended sediment

would normally be required. For these reasons, most of the

water used for domestic supply in this area is probably obtained

from private wells.

Small communities and rural landowners probably obtain

ground water from bedrock aquifers or from the unconsolidated

sediments in river valleys (alluvium or glacial outwash). There

are typically no test data available on ground water in sparsely

populated areas. The unconsolidated sediments aquifer is open

to the surface, so it is highly susceptible to contamination from

surface activities. Septic systems, landfills, and leaking fuel

storage tanks are all possible sources of contamination. The

intrusion of seawater can cause some problems along the coast.

Soils

The dominant soil orders in this MLRA are Gelisols,

Inceptisols, Spodosols, Andisols, and Entisols. The soils in the

area have a subgelic soil temperature class or a cryic soil

temperature regime, an aquic or ustic soil moisture regime, and

mixed or amorphic mineralogy.

Gelepts, Cryepts, Gelods, and Cryods on ridges, steep

mountain slopes, hills, fans, footslopes, and plains formed in

gravelly colluvium and slope alluvium. At the higher

elevations, fractured bedrock is at a shallow or moderate depth

in many of the soils. At the lower elevations, Andisols and

andic subgroups of other orders have a thin or moderately thick

surface layer of silty volcanic ash and loess. These soils range

from shallow to deep and generally are well drained.

Histoturbels and Aquiturbels in swales and depressions on hills,

in seepage areas, and on footslopes and stream terraces formed

in various colluvial and alluvial deposits. They are somewhat

poorly drained or very poorly drained. Histoturbels have a

moderately thick surface layer of organic material. Fibristels in

depressions and shallow basins on stream terraces formed in

thick deposits of organic material. Gelisols are shallow or

moderately deep to permafrost and are poorly drained or very

poorly drained. Cryaquents and Cryofluvents on flood plains,

low stream terraces, and river deltas formed in stratified silty

and sandy alluvium. They commonly have a substratum of

gravelly and cobbly alluvium. They are deep and range from

excessively drained to poorly drained. Many of these soils have

an upper mineral layer of silty volcanic ash, loess, or a mixture

of the two.

Miscellaneous (nonsoil) areas make up about 25 percent of

this MLRA. The most common miscellaneous areas are rock

outcrop, rubble land, and beaches.

Biological Resources

Well drained soils on mountain slopes at low and middle

elevations in this area dominantly support tall alder shrub, tall

and low willow scrub, and low ericaceous scrub. In areas of peat

and moderately well drained mineral soils, low ericaceous

shrub and shrub birch scrub occur along with tussock-forming

sedges or various sedges and grasses in the ground layer. Wet

sedge meadows, sedge-grass meadows, and sedge-moss

meadows are in drainages and along lakeshores. Well drained

soils at the lower elevations on valley bottoms support balsam

poplar, white spruce, and mixed balsam poplar-white spruce

forests. Balsam poplar and mixed forest types generally have an

understory of tall and low shrubs and herbs. Spruce forest

understory commonly is dominated by a nearly continuous

layer of feather mosses with only scattered shrubs and herbs. On

shallow soils at the higher elevations and on convex mountain

slopes and ridges, the most common vegetation is dwarf alpine

scrub dominated by ericaceous shrubs, dryas, and shrub birch.

These communities commonly have a considerable amount of

lichen cover and bare ground.

The major species of mammals inhabiting the area include

brown bear, black bear, moose, caribou, wolf, wolverine, and

various other furbearers. Walrus, spotted seals, and fur seals are

in coastal areas. The sea cliffs provide important nesting habitat

for murres, kittiwakes, fulmars, and cormorants. At the lower

elevations, most of the rivers and streams are important

spawning areas for salmon.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—67%

Forest—8%

Water—5%

Other—20%

Local residents use this remote area primarily for subsistence

hunting, fishing, and gathering. A number of extractable

minerals and other commodities formerly were mined in the

area, but most of the mines have ceased operations. Wild-land

recreation is an increasingly important land use, particularly in

the Wood-Tikchik Lakes area. There are no major resource

concerns in this area. 
of the United States 597

Figure 238-1: Location of MLRA 238 in Land Resource Region X2.

238—Yukon-Kuskokwim Coastal Plain

This area is in the Western Region of Alaska and consists of

the broad, nearly level delta along the lower reaches of the

Yukon and Kuskokwim Rivers, where the rivers empty into the

Bering Sea (fig. 238-1). The area makes up about 29,960 square

miles (77,640 square kilometers). Although the MLRA is

mostly undeveloped wild land and is sparsely populated, there

are approximately 42 villages in scattered areas along the coast

or the banks of the Yukon and Kuskokwim Rivers. The

principal communities are Aniak, Bethel, Hooper Bay, St.

Marys, and Emmonak. This MLRA is entirely within the Yukon

Delta National Wildlife Refuge. A few of the area’s small coastal

islands are included in the Alaska Maritime National Wildlife

Refuge.

Physiography

This area lies within the Bering Shelf Province of the

Intermontane Uplands and Lowlands System. The terrain

consists of a level to rolling delta plain along the lower reaches

of the Yukon and Kuskokwim Rivers. In a few areas, isolated

low hills protrude above the surrounding plain. The Yukon

River runs along the northern edge of the area, and the

Kuskokwim River runs across the southern edge. The area is

crossed by numerous low-gradient streams, many of which are

tributaries or former channels of the Yukon and Kuskokwim

Rivers. Depressions and shallow basins on the plain are dotted

with interconnecting stream channels, wetlands, and thousands

of small and medium-size lakes. The features of the flood plain

include low escarpments, meander scars, oxbow lakes, sloughs,

and multiple channels and islands. The coastline is broken by a

number of large inlets and bays. Baird Inlet forms a large inland

sea behind Nelson Island. Elevation ranges from sea level to

about 300 feet (90 meters) in most of the area, but it is 2,342

feet (714 meters) at the summit of Towak Mountain, on Cape

Romanzof.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Southwest Alaska (1904), 56 percent; Yukon (1903), 43

percent; and Northwest Alaska (1902), 1 percent. Surface water

in the vast majority of interior and western Alaska drains into

the Bering Sea through this MLRA. The major rivers are the

Yukon, Kuskokwim, Tovers, Black, Azun, Kashunuk, and

Izaviknek Rivers. Lakes make up about 40 percent of the area.

This area is in the zone of discontinuous permafrost. The

layer of permafrost is thin or moderately thick and occurs

primarily in fine textured deposits. The maximum depth to the

bottom of the permafrost layer is about 600 feet (185 meters).

Permafrost generally does not occur on flood plains and in

areas near bodies of water.

Geology

This area was unglaciated during the Pleistocene epoch,

except possibly along the extreme southeast edge, where

glaciers from the Ahklun Mountains extended a small distance

down onto the lowlands. Sediments across the vast majority of

the area consist of fine textured, Holocene and Pleistocene

deltaic deposits from the Yukon and Kuskokwim Rivers and

loamy and sandy, Holocene fluvial deposits on flood plains and

stream terraces. A number of low basalt hills and associated

cinder cones and volcanic craters are in scattered areas

throughout the western part of the MLRA. These features date

to the Cretaceous and Tertiary period and are mantled by

Holocene colluvium.

Climate

The average annual precipitation in this area is 15 to 30

inches (380 to 760 millimeters). The climate of the area is

primarily maritime. In winter, when the Bering Sea icepack

forms, however, the climate becomes more continental.

Summers are short and variable. Cloudy and rainy conditions

are common in summer. Windy conditions are common at any

time of the year. Winters are long and cold. Fog and poor

visibility are common, particularly in coastal areas during

winter. The average annual snowfall ranges from about 40 to 90

inches (100 to 230 centimeters). The average annual

temperature is 29 to 33 degrees F (-2 degrees to 1 degree C).

The freeze-free period averages about 80 to 135 days. Freezing
598 Major Land Resource Areas

temperatures can occur in any month, but June, July, and

August generally are freeze-free.

Water

There are very limited withdrawals of freshwater for use in

this sparsely populated MLRA. The only measurable

withdrawal is for public supply (0.2 million gallons, or 0.8

million liters, per day). Most of the communities in the area are

on the coast or along the major rivers and lakes. Because of its

chemical quality, the surface water in the area generally is

suitable for all uses, but the rivers are frozen for much of the

year or flow little during winter. Also, the rivers are typically

fed by glacial meltwater, which carries high loads of suspended

sediment. If surface water is available, treatment for removal of

the suspended sediment would normally be required. For these

reasons, most of the water used for domestic supply in this area

is probably obtained from private wells.

Small communities and rural landowners probably obtain

ground water primarily from unconsolidated sediments in river

valleys or beneath the coastal plain (alluvium or glacial

outwash). There are typically no test data available on ground

water in sparsely populated areas. The unconsolidated sediment

aquifers are open to the surface and are highly susceptible to

contamination from surface activities. Septic systems, landfills,

and leaking fuel storage tanks are all possible sources of

contamination. The intrusion of seawater can be a problem near

the coast.

Soils

The dominant soil orders in this MLRA are Gelisols,

Inceptisols, and Entisols. The soils in the area have a subgelic

soil temperature class or a cryic soil temperature regime, an

aquic or udic soil moisture regime, and dominantly mixed

mineralogy.

Fibristels, Hemistels, Histoturbels, and Aquiturbels are the

most common soils across the broad expanse of the delta.

Fibristels and Hemistels in depressions and shallow basins

formed in thick deposits of organic material over shallow or

moderately deep permafrost. They are very poorly drained.

Mineral soil material, if it occurs, generally is within the

permafrost layer. Historturbels are common in elevated and

convex areas. They formed in a moderately thick layer of

organic material over silty and loamy fluvial sediments.

Aquiturbels on low terraces and in drainageways formed in

stratified silty and sandy alluvial sediments. Histoturbels and

Aquiturbels generally are shallow or moderately deep to

permafrost and are very poorly drained to moderately well

drained. Dystrocryepts on hills and elevated ridges formed in

silty and sandy fluvial sediments. Cryofluvents on flood plains

formed in silty and sandy alluvium. Excessively drained

Cryopsamments on coastal dunes formed in thick deposits of

sand. Very poorly drained Cryofibrists and Cryohemists on

lakeshores formed in thick deposits of organic material.

Inceptisols, Entisols, and Histosols do not have permafrost

within their soil profile.

Miscellaneous (nonsoil) areas make up about 40 percent of

this MLRA. The most common miscellaneous areas are water

and beaches.

Biological Resources

Lakes, ponds, and other kinds of surface water are

throughout most of this area. The vegetation near these bodies

of water includes wet sedge meadows, sedge-shrub meadows,

and sedge-moss meadows. Peat mounds and other low uplands

support low and dwarf scrub dominated by ericaceous shrubs,

tussock-forming sedges, other hydrophytic plants, and mosses.

Sites with better drainage and higher local relief support low

ericaceous scrub with mosses, lichens, low willows, and forbs.

Dense stands of grasses grow on beds of drained thaw lakes. In

the southern and eastern parts of the area, spruce forests and

woodland occur on well drained soils on flood plains and the

better drained soils on uplands. Both white spruce and black

spruce are common. Low ericaceous shrubs, willow, alder, and

mosses are dominant in the understory.

The common species of mammals in the area include brown

bear, black bear, caribou, wolf, and various other furbearers.

Walrus and seals are in some coastal areas. Most of this MLRA

has good-quality habitat for waterfowl, and every year as many

as 750,000 swans and geese use the lowlands as staging and

nesting areas. More than 220 bird species use this MLRA at

various times throughout the year. Among the significant

species nesting in the area are tundra swans, emperor geese,

black brants, spectacled eiders, bristle thighed curlews, white

wagtails, dovekies, and McKays buntings. About 75 percent of

the sandhill cranes in Alaska breed in this MLRA.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—55%

Forest—5%

Water—40%

Local residents use this remote area primarily for subsistence

hunting, fishing, and gathering. Less than 1 percent of the area

is urban. The major soil resource concern is disturbance of the

fragile permafrost-affected soils. Disturbance of the insulating

organic material at the surface results in thawing of the upper

soil layers. This thawing can result in ponding, soil subsidence,

erosion, and disruption of surface drainage. All management

activities should include protection of the organic surface

material and the thermal balance of the soils. 
of the United States 599

Figure 239-1: Location of MLRA 239 in Land Resource Region X2.

239—Northern Bering Sea Islands

This area is in the Western Region of Alaska and includes St.

Lawrence, St. Matthew, and Nunivak Islands and a number of

smaller islands in the northern Bering Sea (fig. 239-1). The area

makes up about 3,575 square miles (9,260 square kilometers).

The major villages in the area are Savoonga and Gambell on St.

Lawrence Island and Mekoryuk on Nunivak Island. All of St.

Matthew Island and a few small islands along the coast of St.

Lawrence Island are included in the Alaska Maritime National

Wildlife Refuge. Much of Nunivak Island is included in the

Yukon Delta National Wildlife Refuge.

Physiography

This area lies within the Bering Shelf Province of the

Intermontane Uplands and Lowlands System. The terrain

consists of nearly level to rolling plains and highlands with

mostly gentle slopes. Steep, low-relief volcanic cones, vents,

and lava flows are common throughout Nunivak Island and are

less common on St. Lawrence Island. Coastal lowlands dotted

with numerous small and medium-size lakes make up a

significant part of St. Lawrence Island. Narrow, discontinuous

sand dunes and sand sheets are along many stretches of the

coast. Elevation ranges from sea level along the coast to 2,207

feet (673 meters) at the summit of Atuk Mountain, on St.

Lawrence Island.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Northwest Alaska (1902), 51 percent, and Southwest Alaska

(1904), 49 percent. Numerous short, high-gradient streams drain

the islands of this MLRA directly into the Bering Sea. On St.

Lawrence Island, lakes make up about 10 percent of the area.

Lakes are less extensive on Nunivak and St. Matthew Islands.

This area is in the zone of discontinuous permafrost. The

layer of permafrost generally is thin or moderately thick and

occurs primarily in fine textured deposits. Permafrost generally

does not occur on flood plains, in coarse textured sediments on

the steep slopes of volcanic cones, along the coast, or near

lakes and other bodies of water. The common periglacial

features in the area include solifluction lobes, frost boils, and

patterned ground on plains and footslopes and in swales on

hills.

Geology

The Northern Bering Sea Islands rise from the submarine

Bering platform. St. Lawrence Island is the most geologically

complex of the islands. It is made up primarily of Cretaceous,

Tertiary, and Quaternary volcanic rocks and some Paleozoic

stratified sedimentary rocks. Coastal lowlands are made up

mostly of Quaternary alluvial and marine sediments. Nunivak

and St. Matthew Islands are made up almost exclusively of

Tertiary and Quaternary volcanic rocks. With the possible

exception of a small area on the western end of St. Lawrence

Island, the MLRA was unglaciated during the Pleistocene

epoch. Most of the modern landscape is mantled with

Quaternary alluvial, marine, and eolian deposits.

Climate

The average annual precipitation in this area is 10 to 25

inches (255 to 635 millimeters). The climate of the area is

maritime much of the year and strongly continental in winter,

when the Bering Sea icepack forms. Summers are short and

cool. Cloudy, foggy, and rainy conditions are common in the

summer. Strong winds are common throughout the year. Winters

are long and cold. The average annual snowfall is about 50 to

80 inches (125 to 205 centimeters). The average annual

temperature at Gambell on St. Lawrence Island is 25 degrees F

(-4 degrees C). The freeze-free period at Gambell averages

about 60 to 90 days.

Water

There are very limited withdrawals of freshwater for use in

this sparsely populated MLRA. Most of the communities in the

area are on the coast. Little surface water is available for use by

island residents. Most of the water used for domestic supply in

this area is probably obtained from private wells.

Small communities and rural landowners on Nunivak and St.

Matthew Islands obtain ground water from volcanic bedrock

aquifers. The water is in joints, fractures, and rubble zones in
600 Major Land Resource Areas

the volcanic rocks. Unconsolidated sediments in river valleys

and on the coastal plain (alluvium or some glacial outwash)

provide ground water for residents of St. Lawrence Island. This

ground water generally occurs as a lens of freshwater floating

on saltwater near the coast. There are typically no test data

available on ground water in sparsely populated areas. If these

aquifers are close to the surface, they are highly susceptible to

contamination from surface activities. Septic systems, landfills,

and leaking fuel storage tanks are all possible sources of

contamination. The intrusion of seawater can be a problem

since most residents live along the coast.

Soils

The dominant soil order in this MLRA is Gelisols. The

MLRA also has small areas of Mollisols and Inceptisols. The

soils in the area have a subgelic soil temperature class or a cryic

soil temperature regime; an aquic, ustic, or udic soil moisture

regime; and mixed mineralogy.

Histoturbels and Aquiturbels on plains, hills, and the lower

mountain slopes formed in gravelly and sandy materials.

Historthels on the same landforms have a moderately thick

surface layer of organic material. The Gelisols are shallow or

moderately deep to permafrost and are poorly drained to

somewhat poorly drained. Dystrocryepts on plains, hills, and

the lower mountain slopes formed in gravelly and sandy

materials, do not have permafrost within their soil profile, and

generally are well drained. Fibristels and Hemistels in

depressions and swales on plains and hills formed in thick

deposits of organic material, are shallow or moderately deep to

permafrost, and are poorly drained. Mollorthels, Molliturbels,

and Haplocryolls on limestone uplands formed in residuum.

Mollorthels and Molliturbels are shallow or moderately deep to

permafrost and are somewhat poorly drained or poorly drained.

Haplocryolls do not have permafrost within their soil profile

and generally are well drained.

Miscellaneous (nonsoil) areas make up about 10 percent of

this MLRA. The most common miscellaneous areas are water,

lava flows, rubble land consisting of volcanic rocks, and sandy

and gravelly beaches.

Biological Resources

The areas of peat and the gentle mountain slopes, plains, and

deeper soils in this MLRA generally support low and dwarf

scrub and sedge-shrub meadows dominated by black crowberry,

ericaceous shrubs, sedges, tussock-forming sedges, and a

variety of forbs and mosses. Shallow soils on convex mountain

slopes and ridges commonly support dwarf alpine scrub

dominated by ericaceous shrubs, dryas, and dwarf willows.

These communities commonly have a considerable amount of

lichen and bare ground. Bedrock exposures with lichens and

scattered shrubs and herbs in pockets of fine earth dominate the

highest elevations and ridges and other windblown sites.

Drainages and the shores of lakes support wet sedge meadows,

sedge-grass meadows, and sedge-moss meadows. Well drained

soils on flood plains commonly support low to tall willow

scrub with dense grasses and forbs in the understory.

Various marine mammals and seabirds inhabit the coastal

waters, rocky shorelines, and sea cliffs in the area. Waterfowl

nest on coastal lowlands. The common marine mammals

include northern fur seals, ribbon seals, sea lions, and walrus.

Seabirds include eiders, cormorants, kittiwakes, puffins,

auklets, oldsquaw, and murres. In winter, flocks of rare

spectacled eiders congregate in openings in the sea ice south of

St. Lawrence Island. Caribou, reindeer, musk ox, arctic fox, and

other small mammals are on many of the islands.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—90%

Water—6%

Other—4%

Local residents use this remote area primarily for subsistence

hunting, fishing, and gathering. Reindeer herding on Nunivak

Island and St. Lawrence Island provides meat and other

products to the residents. Tourism and wild-land recreation are

minor but increasingly important land uses.

The major soil resource concerns are disturbance of the

fragile permafrost-affected soils and erosion of the andic soils

and the steeper soils. Disturbance of the insulating organic

material at the surface results in thawing of the upper soil

layers. This thawing can result in ponding, soil subsidence,

erosion, and disruption of surface drainage. All management

activities should include protection of the organic surface

material and the thermal balance of the soils. 

240—Nulato Hills-Southern Seward

Peninsula Highlands

This area is in the Western Region of Alaska and consists

primarily of the rolling hills, low mountains, and valleys on the

southern Seward Peninsula and western slopes of the Nulato

Hills. The area makes up about 17,920 square miles (46,430

square kilometers). It is primarily undeveloped wild land and is

sparsely populated. The principal communities in the area are

Nome and Unalakleet. A number of other small villages are

along the coast of Norton Sound or the banks of the major

rivers. Roads connect Nome with the villages of Council to the

east, the central Seward Peninsula to the north, and Teller to the
of the United States 601

Figure 240-1: Location of MLRA 240 in Land Resource Region X2.

northwest. Part of the Yukon Delta National Wildlife Refuge is

in this area.

Physiography

This area lies within the Seward Peninsula and Western

Alaska Provinces of the Intermontane Uplands and Lowlands

System. The terrain near the coast of Norton Sound consists of

rolling hills and broad valleys. Rounded, low mountains occur

farther inland. Narrow flood plains border the many clear-water

streams in the area. Narrow, nearly level coastal plains are in a

number of areas along the coast of Norton Sound. Elevation

ranges from sea level to about 3,900 feet (1,190 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Northwest Alaska (1902), 74 percent, and Yukon (1903), 26

percent. Surface water in all of the area drains into Norton

Sound and the Bering Sea by way of numerous short streams

and rivers originating in the mountains. The principal rivers are

the Unalakleet, Koyuk, and Fish Rivers. Lakes make up less

than 1 percent of the area.

This area is in the zone of discontinuous permafrost.

Permafrost is common on coastal plains, on gently sloping

footslopes, and in swales on hills and mountains. It generally

does not occur on flood plains or near lakes and other bodies of

water. Isolated masses of permafrost are in deep, unconsolidated

deposits in the mountains. In the vicinity of Nome, the base of

the permafrost layer is at a depth of as much as 121 feet (37

meters).

Geology

Large areas of the Seward Peninsula were glaciated during

the early and middle Pleistocene. By the late Pleistocene,

glacial ice was limited to the upper elevations. Much of the

MLRA is mantled with fine textured to coarse textured

mountain colluvium and alluvium. Moderately modified or

highly modified glacial moraines and drift and scattered

glaciofluvial deposits are still in glaciated areas. Holocene

deposits fill most of the coastal lowlands. Recent fluvial

deposits are on flood plains and stream terraces. The bedrock

geology of the area consists dominantly of Cretaceous,

Precambrian, and Paleozoic stratified sedimentary rocks and

Cretaceous through Tertiary volcanic rocks. Many coastal areas

and areas at the lower elevations of hills and mountains are

mantled with a thin layer of silty eolian deposits of Holocene

age.

Climate

The average annual precipitation is about 15 to 20 inches

(380 to 510 millimeters) at the lower elevations in this area and

20 to 40 inches (510 to 1,015 millimeters) at the higher

elevations. Most of the precipitation falls as rain in late

summer. The climate of the area is maritime much of the year

and strongly continental in winter, when the Bering Sea

icepack forms. Orographic influences are significant at the

higher elevations. Summers are brief and cool. Cloudy and

windy conditions are common throughout the year. Winters are

long and cold. The average annual snowfall is 40 to about 100

inches (100 to 255 centimeters). The average annual

temperature along the coast is about 26 degrees F (-3 degrees

C). The freeze-free period along the coast averages about 55 to

90 days.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 40%; ground water, 20%

Livestock—surface water, 0%; ground water, 0%

Irrigation—surface water, 0%; ground water, 0%

Other—surface water, 20%; ground water, 20%

The total withdrawals average about 0.5 million gallons per

day (2 million liters per day). About 40 percent is from ground

water sources, and 60 percent is from surface water sources.
602

Permanent streams, originating in the mountainous regions

surrounding this area, bring some surface water to villages and

the town of Homer. The water from the rivers and natural lakes

is used for some public supply, mining, and domestic purposes.

It generally is suitable for all uses. Flooding from ice dams that

form during the spring thaw is a concern in this area.

The ground water used for public supply, domestic purposes,

and mining in this area is primarily from bedrock aquifers.

Some unconsolidated sediments in river valleys or coastal

plains (alluvium or glacial outwash) also provide some water.

The ground water is hard or very hard but is otherwise of

excellent quality. The level of total dissolved solids is fairly

low, about 130 parts per million (milligrams per liter). The level

of iron may exceed the secondary standard for drinking water of

300 parts per billion (micrograms per liter). The secondary

standard is for esthetics. The iron can stain ceramic and

porcelain and precipitate in pipes. Wells in this area generally

are shallow, so these aquifers are highly susceptible to

contamination from runoff. Septic systems, landfills, and

leaking fuel storage tanks are all possible sources of

contamination. The intrusion of seawater can be a problem

along the coast.

Soils

The dominant soil orders in this MLRA are Gelisols,

Inceptisols, and Entisols. The soils in the area have a subgelic

soil temperature class or a cryic soil temperature regime, an

aquic or udic soil moisture regime, and dominantly mixed

mineralogy.

Mollorthels, Aquiturbels, and Histoturbels are common on

mountains, hills, and coastal plains. They formed in loamy and

gravelly colluvium on mountains and hills and in mixed loamy

and gravelly colluvium and slope alluvium on coastal plains.

Many of the soils on mountains and hills are moderately deep

or deep over fractured bedrock. Histoturbels and Aquiturbels

have a moderately thick, in places discontinuous surface layer

of organic material. The Gelisols in the area are shallow or

moderately deep to permafrost and are poorly drained or

somewhat poorly drained. On steep mountain slopes,

particularly at the upper elevations, Dystrocryepts and

Eutrocryepts formed in gravelly colluvium over fractured

bedrock. These soils are shallow to deep over bedrock and are

well drained. The soils on flood plains include Cryofluvents

and Cryorthents that formed in stratified loamy alluvium over

sandy and gravelly alluvium. These soils are deep and range

from somewhat poorly drained to well drained.

Miscellaneous (nonsoil) areas make up about 5 percent of

this MLRA. The most common miscellaneous areas are rock

outcrop, rubble land, and beaches.

Biological Resources

Well drained soils on slopes at low and middle elevations in

this area dominantly support tall alder shrub, tall and low willow

scrub, and low ericaceous shrub scrub. Areas of peat and

moderately well drained mineral soils support low ericaceous

shrub and shrub birch scrub along with tussock-forming sedges

or various sedges and grasses in the ground layer. Drainages

support wet sedge meadows, sedge-grass meadows, and sedgemoss meadows. Well drained soils at the lower elevations on

valley bottoms have open forests and woodland of mixed

spruce and paper birch. The higher elevations and the shallow

soils on convex mountain slopes and ridges commonly support

dwarf alpine scrub dominated by ericaceous shrubs, dryas, and

dwarf willows. These communities commonly have a

considerable amount of lichen and bare ground. Bedrock

exposures with lichens and scattered shrubs and herbs in pockets

of fine earth dominate the highest elevations and ridges.

The common species of mammals in the area include brown

bear, caribou, moose, wolf, and a variety of other furbearers.

Golden eagles inhabit the areas at the higher elevations and

nest in cliffs and other protected sites. Tundra swans and a

variety of other waterfowl nest in the wetlands and ponds in the

area. Coastal areas are inhabited by ribbon seals and walrus.

The Unalakleet River and other rivers support summer runs of

pink salmon.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—57%

Forest—38%

Other—5%

This remote area is used primarily for subsistence hunting,

fishing, and gathering. Also, the Seward Peninsula is used for

reindeer herding. Less than 1 percent of the area is urban.

Mining, primarily placer mining and dredge mining, was once a

major land use and played an important role in the growth and

development of Nome. A number of mines throughout the area

continue to operate.

The major soil resource concern is disturbance of the fragile

permafrost-affected soils. Another concern is the suspended

sediment load in rivers below areas of placer mines.

Disturbance of the insulating organic material at the surface

results in thawing of the upper soil layers. This thawing can

result in ponding, soil subsidence, erosion, and disruption of

surface drainage. All management activities should include

protection of the organic surface material and the thermal

balance of the soils. 
603

Figure Y-1: Location of Land Resource Region Y.

Y—Northern Alaska

This region is in the northern part of Alaska (fig. Y-1). It

includes the northern slope of the Brooks Range, the western

Brooks Range, and the northern and western Seward Peninsula.

The region makes up 125,550 square miles (325,345 square

kilometers).

This region consists of mountains, foothills, and extensive

coastal plains and deltas. Elevation ranges from sea level on the

coast to 8,570 feet (2,613 meters) at the summit of Mt. Igikpak,

in the Brooks Range. The north flanks of the Brooks Range

consist of folded and faulted strata uplifted during the

Cretaceous period. The mountains were extensively glaciated

during the Pleistocene epoch. To the north, the rolling hills,

ridges, and plateaus extend to the gently rolling to level,

unglaciated Arctic Coastal Plain. Periglacial features, such as

patterned ground, pingos, beaded drainages, and gelifluction

lobes, are common throughout the region. The southwest part

of the region, extending into the Seward Peninsula, includes

flood plains, rolling lowlands, and mountains. Surface water

drains to the north and west into the Arctic Ocean and the

Chukchi Sea in most of the region. On the western Seward

Peninsula, however, it drains into the northern Bering Sea.

The arctic climate is dry and cold, characterized by very

short summers and long winters. Most of the region is above

the Arctic Circle and consequently receives continuous

sunlight for several weeks in summer and continuous twilight

for several weeks in winter. The mean annual precipitation

ranges from about 4 to 10 inches (100 to 255 millimeters) at the

lower elevations in the northern and western parts of the region

and from 30 to 40 inches (760 to 1,015 millimeters) at the

higher elevations in the Brooks Range and on the Seward

Peninsula. The average annual temperature ranges from 8 to 22

degrees F (-13 to -6 degrees C). Freezing temperatures can occur

in any month.

The total withdrawals of freshwater in this region average

just under 2 million gallons per day (7 million liters per day).

About 63 percent is from surface water sources, and 37 percent

is from ground water sources. Almost 80 percent of the water is

used for mineral and oil and gas extraction. The rest is used for
604 Major Land Resource Areas

Figure Y-2: Wilderness recreation in an area of Land Resource Region Y.

public supply. The populated parts of the Seward Peninsula and

the Arctic Slope account for almost all of the freshwater used in

this region.

This area is in the zone of continuous permafrost. Permafrost

is shallow or moderately deep, except on steep, coarse textured

soils in the high mountains. Most of the soils in the region are

Gelisols, having permafrost within their soil profile. Orthels and

Turbels, the dominant suborders, occur on all landforms in the

region. Aquorthels and Histoturbels are on the gentler slopes

and on poorly drained hillsides. Glacic subgroups occur near

the coasts. Mollorthels are on some well drained, south-facing

slopes, and Psammorthels are on dunes. Fibristels formed in

thick deposits of organic material in depressions throughout

the region. Coarse textured Gelepts and Gelorthents are on

some steep hillslopes and ridges. They have a mean annual soil

temperature below 32 degrees F (0 degrees C) but do not have

permafrost in their soil profile.

The native vegetation on foothills and lowlands is arctic

tundra with grasses, sedges, mosses, lichens, ericaceous shrubs,

and willows. The native vegetation in mountainous areas is

dominantly alpine tundra with dwarf scrub communities. In

these areas, sedges and lichens dominate the ground cover.

Forested communities occur along the lower Noatak and Kobuk

Rivers in the western part of the region. Reindeer grazing,

wildlife habitat, mineral and petroleum extraction, and

subsistence hunting, fishing, and gathering are the major land

uses in this region. Some areas are used for wilderness

recreation (fig. Y-2). 
of the United States 605

Figure 241-1: Location of MLRA 241 in Land Resource Region Y.

241—Seward Peninsula Highlands

This area is in the Northern Region of Alaska and includes

the broad, rolling uplands and isolated high, rugged mountains

of the central Seward Peninsula, from Cape Prince of Wales east

to the Selawik Hills (fig. 241-1). The area makes up about

13,455 square miles (34,870 square kilometers). It is mainly

undeveloped wild land and is sparsely populated. Teller, Wales,

and a number of smaller villages are in the western part of the

area, along the coast of the Bering and Chukchi Seas. Three

roads, originating in Nome in the Nulato Hills-Southern Seward

Peninsula Highlands (MLRA 240) to the south, provide access

to small portions of the area. Part of the Bering Land Bridge

National Preserve is in this area.

Physiography

This area lies primarily within the Seward Peninsula

Province, but the eastern part is within the Western Alaska

Province. Both of these provinces are within the Intermontane

Uplands and Lowlands System. The terrain consists of

extensive rolling hills, intervening lowlands, and isolated

groups of rugged, moderately high mountains. Narrow flood

plains and stream terraces are along the rivers. Elevation ranges

from sea level along the coast to 4,714 feet (1,437 meters) at the

summit of Mt. Osborn, in the Kigluaik Mountains.

The only Hydrologic Unit Area (identified by a four-digit

number) that makes up this MLRA is Northwest Alaska (1902).

Surface water in the northern part of the area drains into

Kotzebue Sound and the Chukchi Sea via numerous relatively

short rivers. The major rivers in this part of the area are the

Buckland, Kiwalik, and Serpentine Rivers. Surface water in the

western part of the area drains to the west into the northern

Bering Sea. The principal rivers in this part of the area are the

Agiapuk-American, Kougarok, and Kuzitrin Rivers. Lakes

make up less than 2 percent of the area.

This area is in the zone of continuous permafrost.

Moderately thick layers of permafrost are common in most

unconsolidated materials, except along flood plains and in

close proximity to lakes. Periglacial features are common.

Bedrock structures have altiplanation terraces. Unconsolidated

materials in the uplands have gelifluction sheets, benches,

lobes, and high-center polygons. Wet lowlands have low-center

polygons, thermokarst pits, thaw lakes, and pingos. Massive ice

wedges and lenses occur throughout the area.

Geology

During the late Pleistocene epoch, this area was mostly

unglaciated. The York Mountains in the western part of the

area, the Kigluaik and Bendeleben Mountains along the

southern edge, and the upper Kiwalik River drainage were

glaciated in the early and middle Pleistocene. The modern

landscape is mantled with coarse textured to fine textured

colluvium, slope alluvium, and silty loess. Bedrock is at or

near the surface in many upland areas. Recent alluvial and

coastal sediments occur along rivers and near the coast.

Slightly modified to highly modified glacial moraines and

drift are in glaciated areas. The bedrock geology of the area

consists of a complex mixture of rock ages and types.

Stratified sedimentary rocks, ranging in age from Quaternary

to Precambrian, are the dominant rock types. Tertiary or

Quaternary volcanic rocks and inclusions of Cretaceous and

Tertiary igneous rocks are in scattered areas throughout the

MLRA.

Climate

The average annual precipitation ranges from about 10 to 15

inches (255 to 380 millimeters) in the northern and western

parts of this area and from 20 to 40 inches (510 to 1,015

millimeters) in the mountains in the southern and eastern parts.

Brief, cool summers and long, very cold winters characterize

the arctic continental climate across much of the area. In

summer, maritime conditions prevail along the coast of the

Bering Sea. Strong winds are common throughout the area. The

average annual snowfall is about 40 to 100 inches (100 to 255

centimeters). Exposed, windblown ridges generally are free of

snow. The average annual temperature at Wales is 21 degrees F

(-6 degrees C). The freeze-free period at Wales averages about

45 to 75 days. Freezing temperatures can occur in any month of
606 Major Land Resource Areas

the year, particularly in inland areas and at the higher

elevations.

Water

There are very limited withdrawals of freshwater for use in

this sparsely populated MLRA. An estimated 0.1 million

gallons per day (0.4 million liters per day) is used in mining

operations. Most of the communities in the area are along the

major rivers or lakes or on the coast. Because of its chemical

quality, the surface water in the area generally is suitable for

all uses, but the rivers are frozen for much of the year or flow

little during winter. Most of the water used for domestic supply

in this area is probably obtained from private wells.

Small communities and rural landowners probably obtain

ground water either from bedrock aquifers or from

unconsolidated sediments in river valleys (alluvium or glacial

outwash) or beneath the coastal plains. There are typically no

test data available on ground water in sparsely populated areas.

If these aquifers are close to the surface, they are highly

susceptible to contamination from surface activities. Septic

systems, landfills, and leaking fuel storage tanks are all

possible sources of contamination. The intrusion of seawater

can be a problem along the coast.

Soils

The dominant soil orders in this MLRA are Gelisols,

Entisols, and Inceptisols. The soils in the area have a subgelic

or pergelic soil temperature class or a cryic soil temperature

regime, an aquic or udic soil moisture regime, and mixed

mineralogy.

Histoturbels, Aquiturbels, Haplorthels, and Mollorthels on

elongated toeslopes adjacent to coastal areas, on broad interior

uplands and hills, and on mountain slopes formed in colluvium

and slope alluvium. These soils are shallow or moderately deep

to permafrost and are poorly drained or very poorly drained.

Moderately well drained Gelepts and Gelorthents are on some

steep hillslopes and ridges. These soils do not have permafrost

within their soil profile. Fibristels on plains and in depressions,

basins, and drainageways formed in thick deposits of organic

material. They are shallow to permafrost and are very poorly

drained. Mineral soil material, if it occurs in these organic soils,

generally is within the permafrost layer. Cryofluvents on flood

plains and stream terraces formed in sandy to gravelly

alluvium. They generally do not have permafrost within their

soil profile and range from poorly drained to excessively

drained.

Miscellaneous (nonsoil) areas make up about 5 percent of

this MLRA. The most common miscellaneous areas are rock

outcrop, riverwash, and water.

Biological Resources

The uplands in this area generally support dwarf scrub

dominated by dryas, black crowberry, ericaceous shrubs, and

dwarf willow. On shallow, rocky soils and exposed sites,

lichens and scattered herbs dominate the ground layer. Bare

soil and bedrock generally are extensive. On the more mesic

sites, sedges, forbs, and mosses cover most of the surface. The

lower elevations and the deeper soils in the nearly level

uplands and basins generally support low willow and

ericaceous shrub scrub and mesic graminoid herbaceous

communities, commonly with extensive areas of tussockforming sedges. Depressions, drainageways, and other saturated

areas support wet sedge meadows and wet sedge-moss

meadows. The vegetation on flood plains consists of a mixture

of tall and low scrub dominated by various willows, shrub

birch, and alder.

The common species of mammals in the area include brown

bear, caribou, moose, musk ox, black bear, wolf, red fox, a

variety of other furbearers, and rodents. Reindeer were

introduced to the area in the early 1900s to provide industry for

local native residents. Many species of migratory waterfowl and

shore birds nest in areas of wet tundra. Raptors in the area

include gyrfalcon, peregrine falcon, golden eagle, hawks, and

owls.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—88%

Forest—7%

Water—1%

Other—4%

This remote area is used primarily for reindeer herding or for

subsistence hunting, fishing, and gathering. Reindeer provide

meat for local and regional use and a number of other products

for local use and export. Several highly mineralized areas can

be mined. Most of the mining to date has been placer mining

for gold. The largest mine is the Lost River Tin Mine, which

has not operated since the 1960s. A number of mines

throughout the area are still operating.

The major soil resource concern is disturbance of the fragile

permafrost-affected soils. Disturbance of the insulating organic

material at the surface results in thawing of the upper soil

layers. This thawing can result in ponding, soil subsidence,

erosion, and disruption of surface drainage. All management

activities should include protection of the organic surface

material and the thermal balance of the soils. 
of the United States 607

Figure 242-1: Location of MLRA 242 in Land Resource Region Y.

242—Northern Seward PeninsulaSelawik Lowlands

This area is in the Northern Region of Alaska and includes

the mosaic of coastal lowlands, river deltas, gently sloping

uplands, and isolated hills and low mountains along the

northern Seward Peninsula and in the lower Selawik basin at

the head of Kotzebue Sound (fig. 242-1). To the east, the area

extends to the lower slopes of the Purcell Mountains, Zane

Hills, and Sheklukshuk Range. The area makes up 8,165 square

miles (21,155 square kilometers). It is mostly undeveloped wild

land and is sparsely populated. A number of villages are in

scattered areas throughout the MLRA. The largest of these are

Noorvik, Kotzebue, and Shishmaref. Parts of the Bering Land

Bridge National Preserve, a major portion of Selawik National

Wildlife Refuge, and a small part of the Alaska Maritime

National Wildlife Refuge are in this area.

Physiography

This area lies primarily within the Seward Peninsula

Province, but the eastern part lies within the Western Alaska

Province. Both of these provinces are within the Intermontane

Uplands and Lowlands System. The terrain consists of nearly

level to rolling plains, river deltas, and extended mountain

footslopes. Depressions and shallow basins are dotted with

hundreds of small lakes and interconnecting wetlands. Nearly

level, meandering flood plains are along rivers. In a few areas

the landscape is broken by rounded, low-relief hills protruding

above the surrounding lowlands. In general, elevation ranges

from sea level in the coastal lowlands to about 300 feet (90

meters) near the adjacent mountainous areas.

The only Hydrologic Unit Area (identified by a four-digit

number) that makes up this MLRA is Northwest Alaska (1902).

Surface water in the entire area drains into Kotzebue Sound and

the Chukchi Sea. The major river systems that traverse the area

are the Selawik and Buckland Rivers and the Kobuk and

Noatak River deltas. Lakes make up about 25 percent of the

area.

This area is in the zone of continuous permafrost. Thin or

moderately thick layers of permafrost occur primarily in fine

textured deposits. Near Kotzebue, the maximum depth to the

bottom of the permafrost layer is as much as about 240 feet (75

meters). Permafrost generally does not occur on flood plains or

near lakes and other bodies of water. Periglacial features, such

as beaded drainages, patterned ground, thaw gullies, pingos,

and frost boils, occur throughout the area.

Geology

The western part of this area was unglaciated during the

Pleistocene epoch. Most of the eastern part was covered by

glacial ice originating in the Waring Mountains and Brooks

Range to the north. Sediments across the vast majority of the

area consist of fine textured, Holocene and Pleistocene deltaic

and fluvial deposits on coastal lowlands, Holocene fluvial

deposits on flood plains and stream terraces, and mixed

colluvium and slope alluvium on mountain footslopes. The

underlying bedrock geology consists primarily of stratified

sedimentary rocks and volcanic rocks of Cretaceous, Tertiary,

and Quaternary age.

Climate

The average annual precipitation ranges from less than 10

inches (255 millimeters) in coastal lowland areas to 20 to 30

inches (510 to 760 millimeters) in the hills and mountains in

the southern and eastern parts of this area. Brief, cool summers

and long, very cold winters characterize the climate of the area.

In summer, maritime conditions prevail near the coast,

becoming more continental farther inland. In winter, when the

icepack forms on Kotzebue Sound, arctic continental

conditions prevail throughout the area. The average annual

snowfall is about 40 to 60 inches (100 to 150 centimeters). The

average annual temperature at Kotzebue is 22 degrees F (-6

degrees C). The freeze-free period at Kotzebue averages about

75 to 95 days. Freezing temperatures can occur in any month of

the year, particularly at the higher elevations in inland areas.

Water

There are very limited withdrawals of freshwater for use in

this sparsely populated MLRA. Most of the communities in the
608 Major Land Resource Areas

area are along the major rivers or lakes or on the coast. Because

of its chemical quality, the surface water in the area generally is

suitable for all uses, but the rivers are frozen for much of the

year or flow little during winter. Most of the water used for

domestic supply in this area is probably obtained from private

wells.

Small communities and rural landowners probably obtain

ground water either from bedrock aquifers or from

unconsolidated sediments in river valleys (alluvium or glacial

outwash) or beneath coastal plains. There are typically no test

data available on ground water in sparsely populated areas. If

these aquifers are close to the surface, they are highly

susceptible to contamination from surface activities. Septic

systems, landfills, and leaking fuel storage tanks are all

possible sources of contamination. The intrusion of seawater

can be a problem along the coast.

Soils

The dominant soil orders in this MLRA are Gelisols,

Inceptisols, and Entisols. The soils in the area have a subgelic

or pergelic soil temperature class or a cryic soil temperature

regime and generally have an aquic soil moisture regime and

mixed mineralogy.

Fibristels, Histoturbels, and Aquiturbels are the most

common soils on coastal lowlands and deltas. Fibristels in

depressions and shallow basins formed in thick deposits of

organic material and are shallow or moderately deep to

permafrost. Mineral soil material, if it occurs in these organic

soils, generally is within the permafrost layer. These soils are

very poorly drained. Histoturbels and Aquiturbels in elevated

and convex areas on low terraces and long footslopes formed in

silty and sandy material over a gravelly substratum. They are

shallow or moderately deep to permafrost, commonly have

surface microtopography of polygons and stripe hummocks,

and generally are poorly drained or very poorly drained.

Histoturbels have a moderately thick surface layer of organic

material. Gelepts on hills and elevated ridges formed in silty

and sandy fluvial sediments. They do not have permafrost

within their soil profile and generally are well drained or

moderately well drained. Cryorthents, Cryaquents, and

Cryofluvents on flood plains and stream terraces formed in silty

and sandy alluvium. Cryopsamments on coastal dunes formed

in thick deposits of sand. All of these Entisols have no

permafrost within their soil profile and range from very poorly

drained to excessively drained.

Miscellaneous (nonsoil) areas make up about 25 percent of

this MLRA. The most common miscellaneous areas are water

and beaches.

Biological Resources

Lakes and ponds and saturated soils are throughout most of

this area. Areas adjacent to lakes and ponds and areas where

surface water generally occurs include wet sedge meadows,

sedge-shrub meadows, and sedge-moss meadows. Peat mounds

and other low uplands support low and dwarf scrub dominated

by ericaceous shrubs, sedges, other hydrophytic plants, and

mosses. Areas with better drainage and areas of higher local

relief support low ericaceous shrub scrub with common mosses,

lichens, low willows, and forbs. Dense stands of grasses grow on

the beds of drained thaw lakes. Flood plains support low and

tall willow scrub and alder scrub. In the eastern part of the area,

spruce forests and woodland occur on well drained flood plains

and the better drained uplands. Both white spruce and black

spruce are common. Low ericaceous shrubs, willow, alder, and

mosses are dominant in the understory.

The common species of mammals in the area include brown

bear, caribou, wolf, and various other furbearers. Walrus and

seals are in some coastal areas. Most of the area has goodquality habitat for waterfowl. Every year, thousands of swans,

geese, and ducks use the lowlands as staging and nesting areas.

Sandhill cranes and a variety of shore birds and passerine birds

nest throughout the area.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—70%

Forest—5%

Water—24%

Other—1%

Local residents use this remote area primarily for subsistence

hunting, fishing, and gathering. The major soil resource

concern is disturbance of the fragile permafrost-affected soils.

Disturbance of the insulating organic material at the surface

results in thawing of the upper soil layers. This thawing can

result in ponding, soil subsidence, erosion, and disruption of

surface drainage. All management activities should include

protection of the organic surface material and the thermal

balance of the soils. 

243—Western Brooks Range Mountains,

Foothills, and Valleys

This area is in the Northern Region of Alaska and

encompasses the southern slopes of the De Long Mountains,

the Baird Mountains, the Noatak River drainage, and the lower

Kobuk River drainage (fig. 243-1). The southern limit of the

area includes the western Lockwood Hills, Sheklukshuk and

Waring Mountains, and Kiana and Igichuk Hills. The area

makes up 23,070 square miles (59,780 square kilometers). It is

mostly undeveloped wild land and is sparsely populated. The

villages of Noatak, along the lower Noatak River, and Ambler

and Shungnak, along the lower Kobuk River, are the principal
of the United States 609

Figure 243-1: Location of MLRA 243 in Land Resource Region Y.

permanent settlements in the area. Parts of the Gates of the

Arctic National Park and Preserve, Noatak National Preserve,

Kobuk Valley National Park, and Cape Krusenstern National

Monument are in this area.

Physiography

This area lies within the Arctic Mountains Province of the

Rocky Mountain System. The terrain consists of a complex of

flood plains, stream terraces, and rolling hills and upland slopes

along the Noatak River and the lower Kobuk River. These

features quickly give rise to moderately steep foothills and

lower mountain slopes, eventually leading to steep, rugged,

high-relief mountains. The upper mountain slopes generally are

rocky, having extensive surface bedrock and rock rubble. Small

glaciers and permanent snowfields are at the heads of some

high-elevation valleys. Broad flood plains and extended

mountain footslopes along the Kobuk, Squirrel, Ambler, and

lower Noatak Rivers are dotted with numerous small and

medium-size lakes and interconnecting wetlands. Elevation

ranges from about 20 feet (6 meters) along the lower Noatak

River in the western part of the area to 8,570 feet (2,613 meters)

at the summit of Mt. Igikpak, in the eastern part.

The only Hydrologic Unit Area (identified by a four-digit

number) that makes up this MLRA is Northwest Alaska (1902).

Surface water in most of the area drains into the Noatak River

via numerous other rivers. Surface water on the south slopes of

the Baird Mountains drains into the Squirrel River, the Ambler

River, and other tributaries of the Kobuk River. Both the

Noatak and Kobuk Rivers empty into Kotzebue Sound and the

Chukchi Sea. Lakes make up about 3 percent of the area.

This area is in the zone of continuous permafrost. In the

mountains, permafrost is most evident in unconsolidated

materials. In the valleys, thick layers of permafrost occur in

both fine textured and coarse textured materials. Depth to the

base of the permafrost layer may be 1,000 feet (305 meters) or

more. In close proximity to water bodies, it may be 600 feet

(185 meters) or more. Periglacial features, such as pingos,

thermokarst pits, thaw lakes, gelifluction lobes, and high- and

low-center polygons, are common on stream terraces, on the

lower mountain slopes, and in swales on foothills.

Geology

The entire area was glaciated during the early and middle

Pleistocene, except for possibly small portions of the Baird

Mountains. By the late Pleistocene, glaciers had retreated from

most of the area, except for the central, upper-elevation parts of

the De Long Mountains in the northern part of the area. The

valley of the upper Noatak River likely was covered by

extensive proglacial lakes during parts of the Pleistocene

epoch. In the mountains, glacial deposits have eroded away or

have been buried by mountain colluvium and alluvium, which

accumulated during the Holocene epoch across about 60

percent of the present landscape. Slightly modified to highly

modified glacial moraines, drift, and outwash deposits are

extensive on the lower mountain slopes and in valleys at the

mid and lower elevations. These deposits cover about 18

percent of the area. Flood plains, stream terraces, and alluvial

fans have recent and Pleistocene fluvial deposits. The

underlying bedrock geology consists almost entirely of

stratified sedimentary rocks of Paleozoic and Precambrian age

and some of Cretaceous age.

Climate

The average annual precipitation ranges from about 10 to 15

inches (255 to 380 millimeters) at the lower elevations in the

western part of this area and along the central Noatak River and

from about 20 to 40 inches (510 to 1,015 millimeters) in the

mountains. Short, generally cool summers and long, very cold

winters characterize the arctic climate of the area. The average

annual snowfall is about 35 to 100 inches (90 to 255

centimeters). The average annual temperature ranges from

about 8 to 16 degrees F (-13 to -9 degrees C). The length of the

freeze-free period is not known. Snow and freezing

temperatures can occur in any month of the year, particularly at

the higher elevations.

Water

There are very limited withdrawals of freshwater for use in

this sparsely populated MLRA. Most of the communities in the
610 Major Land Resource Areas

area are along the major rivers or lakes or on the coast. Because

of its chemical quality, the surface water in the area generally is

suitable for all uses, but the rivers are frozen for much of the

year or flow little during winter. Most of the water used for

domestic supply in this area is probably obtained from private

wells.

Small communities and rural landowners probably obtain

ground water either from bedrock aquifers or from

unconsolidated sediments in river valleys (alluvium or glacial

outwash) or beneath coastal plains. There are typically no test

data available on ground water in sparsely populated areas. If

these aquifers are close to the surface, they are highly

susceptible to contamination from surface activities. Septic

systems, landfills, and leaking fuel storage tanks are all

possible sources of contamination. The intrusion of seawater

can be a problem along the coast.

Soils

The dominant soil orders in this MLRA are Gelisols,

Entisols, Inceptisols, and Mollisols. The soils in the area have a

subgelic or pergelic soil temperature class or a cryic soil

temperature regime, an aquic or udic soil moisture regime, and

mixed mineralogy.

Histoturbels, Aquiturbels, and Haploturbels formed in loamy

to gravelly and stony colluvium, slope alluvium, and glacial

drift on slopes, ridges, and fans in the mountains; on foothills,

long upland slopes, and high terraces; and on flats in valleys.

Histoturbels have a moderately thick surface layer of organic

material. The soils on the upper mountain slopes and ridges

generally are shallow to deep over fractured bedrock. The

Histoturbels, Aquiturbels, and Haploturbels are shallow or

moderately deep to permafrost and are poorly drained or very

poorly drained. Fibristels in depressions, in shallow basins, and

along lake margins formed in thick deposits of organic

material. These soils are shallow or moderately deep to

permafrost and are very poorly drained to somewhat poorly

drained. Gelorthents, Gelepts, and Gelolls on the upper

mountain slopes and ridges formed in loamy to stony

colluvium and residuum. These soils are shallow to deep and

generally are well drained. Cryofluvents on flood plains formed

in stratified loamy, sandy, and gravelly alluvium and are well

drained.

Miscellaneous (nonsoil) areas make up about 27 percent of

this MLRA. The most common miscellaneous areas are rock

outcrop, rubble land, and water.

Biological Resources

The mountain slopes and ridges in this area generally

support dwarf scrub dominated by dryas, black crowberry,

ericaceous shrubs, and dwarf willow. On shallow, rocky soils

and exposed sites, lichens and scattered herbs dominate the

ground layer. Bare soil and bedrock generally are extensive. On

the more mesic sites, sedges, forbs, and mosses cover most of

the surface. The lower elevations and deeper soils in areas of

nearly level uplands, terraces, and basins generally support low

willow and ericaceous shrub scrub and mesic graminoid

herbaceous communities, commonly with extensive areas of

tussock-forming sedges. Depressions, drainageways, and other

saturated sites support wet sedge meadows and wet sedge-moss

meadows. Flood plains support a mixture of tall and low scrub

dominated by various willows, shrub birch, and alder. Along the

lower Noatak and Kobuk Rivers, white spruce and mixed

spruce-balsam poplar forests and woodland are associated with

the scrub.

The common species of mammals in the area include brown

bear, caribou, moose, musk ox, black bear, wolf, red fox, a

variety of other furbearers, and rodents. Many species of

migratory waterfowl and shore birds nest in the ponds and

wetlands in the area. Raptors in the area include gyrfalcon,

peregrine falcon, golden eagle, hawks, and owls. Arctic char

and arctic grayling are in most of the rivers. Lake trout and

northern pike are common in many lakes.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—59%

Forest—14%

Water—3%

Other—24%

Local residents use this remote area primarily for subsistence

hunting, fishing, and gathering. Hunting and other kinds of

wild-land recreation are increasingly important land uses. Most

visitors are served by air taxi, guiding, and outfitting

companies operating out of the major Alaska communities.

The major soil resource concern is disturbance of the fragile

permafrost-affected soils. Disturbance of the insulating organic

material at the surface results in thawing of the upper soil

layers. This thawing can result in ponding, soil subsidence,

erosion, and disruption of surface drainage. All management

activities should include protection of the organic surface

material and the thermal balance of the soils. 

244—Northern Brooks Range Mountains

This area is in the Northern Region of Alaska and includes

the high mountains and valleys on the northern side of the

Brooks Range, where surface water drains into the Colville

River and other Arctic Ocean drainage basins (fig. 244-1). The

area makes up 15,695 square miles (40,675 square kilometers).

It is entirely remote wild land and is sparsely populated. The

only village in the area is Anaktuvuk Pass, along the boundary

with the Interior Brooks Range Mountains (MLRA 234). The
of the United States 611

Figure 244-1: Location of MLRA 244 in Land Resource Region Y.

Dalton Highway (known locally as the Haul Road) and the

Trans-Alaska Pipeline bisect the Brooks Range at Atigun Pass.

Parts of the Gates of the Arctic National Park and Preserve and

Arctic National Wildlife Refuge and the extreme southern part

of the National Petroleum Reserve are in this area.

Physiography

This area lies within the Arctic Mountains Province of the

Rocky Mountain System. The Brooks Range is the most

northerly extension of the Rocky Mountains. The terrain

consists of steep, rugged, high mountains and narrow valleys.

In places small glaciers occur at the higher elevations,

particularly in the Romanzof Mountains, in the eastern part of

the area. The upper mountain slopes generally are rocky,

having extensive surface bedrock and rock rubble. The lower

slopes are characterized by coalescing fans and steep footslopes

that extend to stream channels in narrow valleys. The bottoms

of the valleys along the larger rivers and streams have nearly

level flood plains and stream terraces and some rolling

uplands. Elevation ranges from about 1,969 feet (600 meters)

along the edge of the Arctic Foothills (MLRA 245) to 8,570

feet (2,613 meters) at the summit of Mt. Igikpak, in the western

part of the area, along the border with the adjacent Brooks

Range MLRAs.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Arctic Slope (1901), 98 percent, and Yukon (1903), 2 percent.

Numerous rivers drain this MLRA through the Arctic Foothills

and Coastal Plain to the Arctic Ocean. The major rivers are the

Kongakut, Aichilik, Jago, Canning, Ivishak, Ribdon, Atigun,

Anaktuvuk, and Killik Rivers. Lakes make up less than 2

percent of the area.

This area is in the zone of continuous permafrost. In the

mountains, permafrost is most evident in areas of deep

unconsolidated deposits. In valleys, thick layers of permafrost

occur in both fine textured and coarse textured deposits.

Periglacial features, including gelifluction lobes, polygons, and

stripes, are common on stream terraces, on hills, and in gently

sloping areas in the mountains.

Geology

Except for the highest peaks, the steep upper ridges, and

occasional unglaciated valleys, most of this area was covered

with glacial ice during the early and middle Pleistocene. In

many places, the ice extended northward down onto the

adjacent Arctic Foothills (MLRA 245). By the late Pleistocene,

only the highest valleys and mountains remained glaciated.

Most glacial deposits have eroded away or have been buried by

mountain colluvium and alluvium, which accumulated during

the Holocene epoch across about 75 percent of the present

landscape. Slightly modified to highly modified glacial

moraines, drift, and outwash deposits are extensive on the

lower mountain slopes and in valleys at the lower elevations.

These deposits cover about 20 percent of the area. Flood

plains, stream terraces, and alluvial fans have recent and

Pleistocene fluvial deposits. The underlying bedrock geology

consists almost entirely of stratified sedimentary rocks of

Paleozoic and Precambrian age. Inclusions of Paleozoic and

early Jurassic volcanic and igneous rocks occur in the eastern

part of the area.

Climate

The average annual precipitation throughout most of this

area ranges from 15 to 40 inches (380 to 1,015 millimeters).

Brief, cool summers and long, very cold winters characterize

the arctic climate of the area. The average annual snowfall is

about 50 to 100 inches (125 to 255 centimeters). The average

annual temperature ranges from about 8 to 16 degrees F (-13 to

-9 degrees C). The length of the freeze-free period is not known.

Freezing temperatures can occur in any month of the year.

Water

There are very limited withdrawals of freshwater for use in

this sparsely populated MLRA. Most of the communities in the

area are along the major rivers at the lower elevations. Because

of its chemical quality, the surface water in the area generally is

suitable for all uses, but the rivers are frozen for much of the
612 Major Land Resource Areas

year or flow little during winter. Most of the water used for

domestic supply in this area is probably obtained from private

wells.

Small communities and rural landowners probably obtain

ground water either from bedrock aquifers or from

unconsolidated sediments in river valleys (alluvium or glacial

outwash). There are typically no test data available on ground

water in sparsely populated areas. If these aquifers are close to

the surface, they are highly susceptible to contamination from

surface activities. Septic systems, landfills, and leaking fuel

storage tanks are all possible sources of contamination.

Soils

The dominant soil order in this MLRA is Gelisols. The soils

in the area generally have a pergelic soil temperature class, an

aquic or udic soil moisture regime, and mixed mineralogy.

Aquiturbels, Histoturbels, Molliturbels, and Haploturbels

formed in loamy to stony colluvium, slope alluvium, and

residuum. These soils are shallow or moderately deep to

permafrost and are poorly drained or very poorly drained.

Fibristels in depressions, drainageways, and basins formed in

thick deposits of organic material, are shallow or moderately

deep to permafrost, and are very poorly drained.

Miscellaneous (nonsoil) areas make up about 75 percent of

this MLRA. The most common miscellaneous areas are rubble

land, chutes, rock outcrop, and small glaciers.

Biological Resources

Because of the shallow soils, high winds, and harsh climate,

the vegetation in this area is sparse and is generally limited to

valleys and the lower mountain slopes. Dwarf scrub

communities on mountain slopes and ridges are dominated by

black crowberry, ericaceous shrubs, dryas, and dwarf willow. On

shallow, rocky soils and exposed sites, lichens and scattered

herbs dominate the ground layer. Bare soil and bedrock

generally are extensive. On the more mesic sites, sedges, forbs,

and mosses cover most of the surface. The lower elevations and

deeper soils in basins and on terraces generally support low

willow and ericaceous shrub scrub and mesic graminoid

herbaceous communities, commonly with extensive areas of

tussock-forming sedges. Depressions, drainageways, and other

saturated sites support wet sedge meadows, sedge-shrub

meadows, and wet sedge-moss meadows. Low and tall willow

scrub is dominant on flood plains.

The common species of mammals in the area include brown

bear, black bear, wolf, caribou, and Dall sheep. The smaller

mammals include marmot, red fox, arctic fox, wolverine,

ground squirrel, lemming, and pika. The common raptors in

many areas include golden eagles, marsh hawks, and snowy

owls.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—25%

Forest—2%

Other—73%

Residents of nearby villages use this remote area primarily

for subsistence hunting, fishing, and gathering. The area also is

used widely for sport hunting and other kinds of wild-land

recreation. Most visitors are served by air taxi, guiding, and

outfitting companies operating out of the major Alaska

communities. Mineral resources have been prospected and

mined in a number of places. Construction and maintenance of

the Dalton Highway have led to development of numerous sand

and gravel pits along the road corridor.

Generally, no major resource concerns affect land use in this

sparsely populated area. Because of the highways and pipeline

that cross the area, however, disturbance of the fragile

permafrost-affected soils is a concern. Disturbance of the

insulating organic material at the surface results in thawing of

the upper soil layers. This thawing can result in ponding, soil

subsidence, erosion, and disruption of surface drainage. All

management activities should include protection of the organic

surface material and the thermal balance of the soils. 

245—Arctic Foothills

This area is in the Northern Region of Alaska and includes

the broad, rounded hills and nearly level uplands at the base of

the Brooks Range from Point Hope in the west to Demarcation

Point in the east (fig. 245-1). The area makes up about 42,305

square miles (109,625 square kilometers). It is entirely

undeveloped wild land and is sparsely populated. The only

villages are Umiat, in the central part of the area, and Kivalina

and Point Hope, along the coast of the Arctic Ocean in the

western part of the area. The Dalton Highway (known locally as

the Haul Road) and the Trans-Alaska Pipeline bisect this

MLRA west of the Sagavanirktok River. Parts of the National

Petroleum Reserve and Arctic National Wildlife Refuge are in

this area.

Physiography

This area lies within the Arctic Foothills Province of the

Rocky Mountain System. The northern part of the area consists

of broad, rounded ridges and mesa-like uplands. The southern

part, which is higher than the northern part, consists of irregular

buttes, mesas, and linear ridges with intervening undulating

plains and plateaus. Many streams and rivers are in swales and
of the United States 613

Figure 245-1: Location of MLRA 245 in Land Resource Region Y.

valleys between hills. Most rivers are confined to a single,

moderate-gradient, slightly meandering channel. Braided

sections occur across level areas. Elevation generally ranges

from about 655 feet (200 meters) in the northern part of the

area, along the border with the Arctic Coastal Plain (MLRA

246), to about 2,000 feet (610 meters) in the southern part,

along the border with the Northern Brooks Range Mountains

(MLRA 244). Some hills bordering the Brooks Range reach an

elevation of 3,600 feet (1,100 meters).

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Arctic Slope (1901), 95 percent, and Northwest Alaska (1902), 5

percent. Numerous rivers originating in the Brooks Range drain

through the Arctic Coastal Plain to the Arctic Ocean. The major

drainage is that of the Colville River. Other major rivers are the

Canning and Sagavanirktok Rivers. Lakes make up less than 2

percent of the area.

This area is in the zone of continuous permafrost. Thick

layers of permafrost occur in both fine textured and coarse

textured deposits. Depth to the base of the permafrost layer is as

much as 2,100 feet (640 meters). Periglacial features, such as

pingos, gelifluction lobes, and patterned ground, occur

throughout the area.

Geology

This area remained unglaciated during the Pleistocene

epoch, except possibly for the upper areas along the edge of the

Northern Brooks Range Mountains (MLRA 244). Bedrock and

coarse to fine rubble mantle the surface on convex uplands.

Elsewhere, Quaternary surface deposits include various

alluvial, eolian, or glaciofluvial materials. Slightly modified to

highly modified moraines and drift occur in areas adjacent to

the Brooks Range. The bedrock geology of the area consists

primarily of Cretaceous and late Paleozoic to lower Mesozoic

stratified sedimentary rocks. These rocks occur in about 67

percent of the area. The rest of the area consists of uplifted

Cretaceous and Tertiary continental deposits.

Climate

The average annual precipitation is less than 10 inches (255

millimeters) at the lower elevations along the northern

boundary of this area with the Arctic Coastal Plain (MLRA 246)

and ranges from 15 to 20 inches (380 to 510 millimeters) at the

higher elevations in the southern part of the area. Brief, cool

summers and long, very cold winters characterize the arctic

climate of the area. The average annual snowfall ranges from

about 40 to 60 inches (100 to 150 centimeters). The average

annual temperature ranges from 10 to 18 degrees F (-12 to -8

degrees C). The average freeze-free period is fewer than 10 days

to 55 days.

Water

There are very limited withdrawals of freshwater for use in

this sparsely populated MLRA. Most of the communities in the

area are along the major rivers at the lower elevations or are on

the coast. Some mining and oil and gas extraction operations

use some surface water in this area. Because of its chemical

quality, the surface water in the area generally is suitable for all

uses, but the rivers are frozen for much of the year or flow little

during winter. Most of the water used for domestic supply in

this area is probably obtained from private wells.

Most small communities, rural landowners, and mineral

industries probably obtain ground water either from bedrock

aquifers or from unconsolidated sediments in river valleys

(alluvium or glacial outwash). There are typically no test data

available on ground water in sparsely populated areas. If these

aquifers are close to the surface, they are highly susceptible to

contamination from surface activities. Septic systems, landfills,

leaking fuel storage tanks, and waste from mineral, oil, and gas

extraction are all possible sources of contamination. The

intrusion of seawater can be a problem along the coast.

Soils

The dominant soil order in this MLRA is Gelisols. Entisols

and Inceptisols are of minor extent. Most of the soils in the area

have a pergelic soil temperature class, an aquic soil moisture

regime, and mixed mineralogy. The soils generally are shallow
614 Major Land Resource Areas

Figure 246-1: Location of MLRA 246 in Land Resource Region Y.

or moderately deep to permafrost, are poorly drained or very

poorly drained, and are loamy and gravelly.

Aquiturbels, Histoturbels, and Molliturbels formed in loamy

and gravelly colluvium and slope alluvium on ridges, gently

sloping to steep hills, and valley bottoms and in gravelly

alluvium on stream terraces. Moderately well drained Gelepts

and Gelorthents are on some steep hillsides. These soils have a

cryic soil temperature regime and do not have permafrost

within their soil profile. Fibristels in depressions, on valley

bottoms, and in drainageways formed in thick deposits of

organic material.

Miscellaneous (nonsoil) areas make up about 4 percent of

this area. The most common miscellaneous areas are rock

outcrop, talus, and ice.

Biological Resources

The uplands in this area generally support dwarf scrub

dominated by dryas, black crowberry, ericaceous shrubs, and

dwarf willow. On shallow, rocky soils and exposed sites, lichens

and scattered herbs dominate the ground layer. Bare soil and

bedrock generally are extensive. On the more mesic sites,

sedges, forbs, and mosses cover most of the surface. The mesic

sites and deeper soils in valleys, in basins, and on terraces

generally support low and dwarf willow and ericaceous shrub

scrub and mesic graminoid herbaceous communities,

commonly with extensive areas of tussock-forming sedges.

Depressions, drainageways, and other saturated sites support

wet sedge meadows and wet sedge-moss meadows. Flood plains

support a mixture of tall and low scrub dominated by various

willows, shrub birch, and some alder.

The common species of mammals in the area include brown

bear, wolf, wolverine, caribou, arctic fox, snowshoe and tundra

hare, hoary marmot, brown lemming, and northern bog

lemming. Musk oxen, which were decimated by hunting in the

late 1800s, are becoming more common in many places. The

common birds in the area include willow ptarmigan, roughlegged hawk, American golden plover, short-eared owl, and

snowy owl. Arctic char and arctic grayling are in most of the

rivers.

Land Use

Following are the various kinds of land use in this MLRA:

Grassland—96%

Water—1%

Other—3%

Local residents use this area primarily for subsistence

hunting, fishing, and gathering. Sport hunting and other kinds

of wild-land recreation are becoming increasingly important

land uses. Most visitors are served by air taxi, guiding, and

outfitting companies operating out of the major Alaska

communities. Some limited extraction of minerals, including

oil and gas, occurs in local areas.

The major soil resource concern is disturbance of the fragile

permafrost-affected soils. Disturbance of the insulating organic

material at the surface results in thawing of the upper soil

layers. This thawing can result in ponding, soil subsidence,

erosion, and disruption of surface drainage. All management

activities should include protection of the organic surface

material and the thermal balance of the soils. 

246—Arctic Coastal Plain

This area is in the Northern Region of Alaska and consists of

a level to gently rolling plain along the coast of the Arctic

Ocean (fig. 246-1). The area makes up about 22,860 square

miles (59,240 square kilometers). It is mostly remote wild land

and is sparsely populated. Permanent settlements include Point

Lay, Wainwright, Barrow, Nuigsut, and Kaktovik. The Prudhoe

Bay oil fields and the northern terminus of the Trans-Alaska

Pipeline are in the central part of the area. The Dalton Highway

(known locally as the Haul Road) and the Trans-Alaska

Pipeline bisect the area west of the Sagavanirktok River,

terminating at Deadhorse. The community of Deadhorse

provides much of the industrial infrastructure and many of the

residential facilities associated with the oil fields and pipeline.

Parts of the National Petroleum Reserve and Arctic National

Wildlife Refuge are in this area.
of the United States 615

Physiography

This area lies within the Arctic Coastal Plain Province of the

Interior Plains System. The terrain consists of a level to gently

rolling plain rising from the Arctic Ocean to the Arctic

Foothills (MLRA 245). The area is dotted by thousands of

small and medium-size lakes and interconnecting wetlands.

Many of the lakes are elongated thaw lakes, which are

consistently oriented from north to northwest. Narrow, nearly

level flood plains and stream terraces are along the many rivers

that cross the area. In the central part of the area, near the coast,

small sand dunes also occur along the rivers. Elevation ranges

from sea level to about 655 feet (200 meters).

The only Hydrologic Unit Area (identified by a four-digit

number) that makes up this MLRA is Arctic Slope (1901).

Numerous rivers, mostly originating in the Brooks Range to

the south, drain from this MLRA to the Arctic Ocean. The

major rivers are the Canning, Colville, Jago, Kongakut, Kuk,

Utukok, and Sagavanirktok Rivers. Lakes and other kinds of

surface water make up about 20 percent of the area.

This area is in the zone of continuous permafrost. Thick

layers of permafrost occur in both fine textured and coarse

textured deposits. Depth to the base of the permafrost layer is

as much as 2,100 feet (640 meters). Periglacial features, such as

beaded drainages, patterned ground, thaw gullies, pingos, and

frost boils, occur throughout the area.

Geology

This area was never glaciated. The bedrock geology consists

of Cretaceous and Tertiary stratified sedimentary rocks and

uplifted continental deposits. The modern landscape is

mantled with Quaternary deposits of alluvial, eolian, or

glaciofluvial origin.

Climate

The average annual precipitation in this area is 4 to 6 inches

(100 to 150 millimeters). Brief, cool summers and long, very

cold winters characterize the arctic climate of the area. The

average annual snowfall is about 20 to 40 inches (50 to 100

centimeters). The average annual temperature ranges from 8 to

14 degrees F (-15 to -10 degrees C). The average freeze-free

period is fewer than 5 days to 20 days. Freezing temperatures

can occur in any month.

Water

Following are the estimated withdrawals of freshwater by

use in this MLRA:

Public supply—surface water, 5.9%; ground water, 17.6%

Livestock—surface water, 0.0%; ground water, 0.0%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 58.8%; ground water, 17.6%

The total withdrawals average less than 2 million gallons per

day (6 million liters per day). About 35 percent is from ground

water sources, and 65 percent is from surface water sources.

Mineral and oil and gas extraction operations use most of the

surface water in this area. Some communities along the major

rivers or on the coast use some surface water for their public

supply. Because of its chemical quality, the surface water in the

area generally is suitable for all uses, but the rivers are frozen or

flow little during winter. Most of the water used for domestic

supply in this area is probably obtained from private wells.

Most small communities, rural landowners, and mineral

industries obtain ground water from unconsolidated sediments

in river valleys (alluvium or glacial outwash) or beneath the

coastal plain. There are typically no test data available on

ground water in sparsely populated areas. If these aquifers are

close to the surface, they are highly susceptible to

contamination from surface activities. Septic systems, landfills,

leaking fuel storage tanks, and waste from mineral, oil, and gas

extraction are all possible sources of contamination. The

intrusion of seawater can be a problem along the coast.

Soils

The dominant soil order in this MLRA is Gelisols. The soils

in the area have a pergelic soil temperature class. Most have an

aquic soil moisture regime and mixed mineralogy. All of the

soils have permafrost. They are generally shallow or moderately

deep to permafrost and are poorly drained or very poorly

drained.

Aquiturbels, Histoturbels, and Haploturbels on nearly level

to rolling plains, low hills, and pingos formed in loamy to

gravelly sediments. Aquiturbels and Haplorthels on flood plains

and stream terraces formed in sandy and gravelly alluvium.

Psammoturbels on dunes formed in thick deposits of sandy

material. Aquiturbels are in areas between the dunes. Fibristels

in depressions, basins, and drainageways and along lake

margins formed in thick deposits of organic material.

Miscellaneous (nonsoil) areas make up about 20 percent of

this MLRA. The most common miscellaneous areas are water,

riverwash, and beaches.

Biological Resources

Wet soil conditions are prevalent across much of this area.

The vegetation in the area occurs primarily in a variety of mesic

and wet sedge, sedge-grass, and sedge-moss meadows. The drier

sites and low uplands support dwarf scrub dominated by dryas,

black crowberry, ericaceous shrubs, and dwarf willow. On

shallow, rocky soils and exposed sites, lichens and scattered

herbs dominate the ground layer. Bare soil and bedrock

generally are extensive. Flood plains support a mixture of low

willow scrub and scattered herbs.

The common species of mammals in the area include brown

bear, wolf, wolverine, caribou, arctic hare, mink, weasel, and
616

lemming. Small herds of musk oxen are in scattered areas

throughout the MLRA. This species was decimated by hunting

in the late 1800s and reintroduced to the area in 1969. Pack ice

and coastal areas are inhabited by polar bear, walrus, and arctic

fox. Many species of migratory waterfowl, including lesser

snow goose, tundra swans, brant, and common eider, nest in the

lakes and ponds in the area. Sea birds, including the pomarine

jaeger, glaucous gull, and black guillemot, are abundant along

the coast. A wide variety of passerine birds and shore birds use

the upland and wetland habitats throughout the area.

Land Use

Following are the kinds of land use in this MLRA:

Grassland—80%

Water—20%

Local residents use this area primarily for subsistence

hunting, fishing, and gathering. Sport hunting and other kinds

of wild-land recreation are becoming increasingly important

land uses. Most visitors are served by air taxi, guiding, and

outfitting companies operating out of the major Alaska

communities. Less than 1 percent of the area is urban. Oil and

gas extraction and the related industrial development occur in

some areas.

The major soil resource concern is disturbance of the fragile

permafrost-affected soils. Disturbance of the insulating organic

material at the surface results in thawing of the upper soil

layers. This thawing can result in ponding, soil subsidence,

erosion, and disruption of surface drainage. All management

activities should include protection of the organic surface

material and the thermal balance of the soils. Oil spills and

other kinds of industrial pollution are serious concerns in areas

of oil extraction and industrial development. 
617

Figure Z-1: Location of Land Resource Region Z.

Z—Caribbean Region

This region (shown in fig. Z-1) includes Puerto Rico (94

percent); the U.S. Virgin Islands of St. Croix, St. Thomas, and St.

John (4 percent); and the outlying islands of Vieques, Culebra,

Desecheo, and Mona (2 percent). It makes up 3,595 square

miles (9,310 square kilometers).

This is a region of humid and semiarid mountains, valleys

(fig. Z-2), and coastal plains. It has a long, warm growing

season. The average annual precipitation ranges from 60 to 90

inches (1,525 to 2,285 millimeters) in the humid uplands, 45 to

60 inches (1,145 to 1,525 millimeters) on the humid coastal

plains, 30 to 45 inches (760 to 1,145 millimeters) in the

semiarid mountains and valleys, and 10 to 45 inches (255 to

1,145 millimeters) on the semiarid coastal plains. The area of

rain forest in northwest Puerto Rico has the highest average

annual precipitation, 120 to 200 inches (3,050 to 5,080

millimeters). The average annual temperature is 70 to 74

degrees F (21 to 23 degrees C) in the humid uplands, 77

degrees F (25 degrees C) on the humid coastal plains, and 79

degrees F (26 degrees C) in the semiarid mountains and valleys

and on the semiarid coastal plains. This region is freeze-free.

Puerto Rico is surrounded by the Atlantic Ocean to the north

and by the Caribbean Sea to the south. Approximately threefourths of the island consists of mountain ranges. Cerro de

Punta, the highest peak, is at an elevation of 4,389 feet (1,338

meters), and El Yunque, in the rain forest, is at an elevation of

3,493 feet (1,065 meters). Other prominent physical features are

limestone karst in the northwestern part of the region and

coastal plains of varying width along the northern and southern

coasts. Slopes are 15 percent or less in about 15 percent of this

region, 16 to 45 percent in 25 percent of the region, and more

than 45 percent in the rest of the region.

The total withdrawals of freshwater in this region average

about 595 million gallons per day (2,250 million liters per

day). About 72 percent is from surface water sources, and 28

percent is from ground water sources. Most of the surface water

used in the region is from storage tanks or cisterns fed by

rainwater catchments. About 71 percent of all the water used in

this heavily populated region is for public supply. About 24

percent is used for irrigation.

The soils in this region include a wide range of Inceptisols,

Ultisols, Oxisols, Mollisols, Entisols, Alfisols, and Histosols.

The dominant suborders are Ustepts, Udepts, and Humults in
618 Major Land Resource Areas

Figure Z-2: Valley and mountains in an area of Land Resource Region Z.

the mountainous areas and Udults and Udox on the coastal

plains. Poorly drained Aquepts, Aquolls, and Aquents are

common on flood plains, and Ustolls and Udolls are in the

better drained areas. Rendolls and Udalfs occur in areas of

limestone karst. Saprists occur in depressions. Generally, the

soils have a thermic or isohyperthermic soil temperature

regime, an ustic or udic soil moisture regime, and mixed or

smectitic mineralogy.

About 96 percent of the land in this region is privately

owned. Pasture of native and improved grasses grown for dairy

and beef enterprises is the main land use. Forestland, mostly

unimproved, is widespread, especially in the humid uplands.

The climax vegetation consists of forest species. Food crops,

such as plantains, bananas, yams, mangos, taniers, vegetables,

and some citrus fruit and coconuts, are grown in the region.

Some unique farmland is used for pineapples or rice. The

importance of sugarcane, once the main cash crop in the region,

has declined because many sugar mills have been closed.

Coffee grown under shade was once a prosperous enterprise, but

hurricanes and other problems have contributed to the decline

of this enterprise. Urban developments, highways, and

recreational areas are encroaching on the better farmland,

especially near metropolitan areas. The main limitations of the

soils in the region are shallowness to bedrock and steepness of

slope. 
of the United States 619

Figure 270-1: Location of MLRA 270 in Land Resource Region Z.

270—Humid Mountains and Valleys

This area is in central Puerto Rico (fig. 270-1). It makes up

about 1,800 square miles (4,660 square kilometers), which is 53

percent of Puerto Rico. From west to east, the towns of Las

Marías, Maricao, Adjuntas, Utuado, Jayuya, Villalba, Orocovis,

Barranquitas, Comerío, Cidra, Caguas, San Lorenzo, and Las

Piedras are in this area. A number of State parks and forest

preserves are in the area. Examples are the “Monte del Estado,”

the “Bosque de Guilarte,” and part of the “Bosque de Susúa.”

The Caribbean National Forest (El Yunque), a rain forest, is at

the eastern end of the area.

Physiography

This mountainous area has very steep slopes and very

narrow to indistinct valleys. Landslides are common in the

area. Elevation ranges from 160 to 4,400 feet (50 to 1,340

meters).

Three different mountain ranges occur in the area. The

Central Ridge, “Cordillera Central” as it is known locally, is the

highest and largest of the three. It is truly in the center of the

island and is oriented in a general east-west direction. Cerro de

Punta, its highest peak, is 4,389 feet (1,338 meters) above sea

level. Los Tres Picachos and Monte Guilarte are about 3,952

feet (1,205 meters) high.

Second in extent and elevation is the Sierra de Luquillo

mountain range in the northeastern part of Puerto Rico. The

three highest peaks in this range are El Toro, 3,523 feet (1,074

meters) above sea level; El Yunque, 3,493 feet (1,065 meters);

and Pico del Este, 3,447 feet (1,051 meters). Because of its

elevation and location on the island relative to the easterly

trade winds, a rain forest (El Yunque) occurs on the higher parts

of this range.

The third mountain range is the Sierra de Cayey, in the eastcentral part of Puerto Rico. The highest peaks in this range are

Cerro La Santa, 2,962 feet (903 meters) high, and Cerro de la

Tabla, 2,919 feet (890 meters) high.

Contrasting with the strongly dissected uplands are the

small areas of undulating landscapes that occur at elevations of

1,640 to 1,970 feet (500 to 600 meters) near Barranquitas in

east-central Puerto Rico. These landscapes are remnants of a

Miocene geomorphic surface, known as the St. John Peneplain,

that escaped erosion.

The only Hydrologic Unit Area (identified by a four-digit

number) that makes up this MLRA is Puerto Rico (2101). This

MLRA includes the headwaters of almost all of the rivers and

streams on the island.

Geology

Most of this MLRA consists of volcanic rocks that formed

below sea level during the Cretaceous period (135 to 70

million years ago). The various formations consist mainly of

volcaniclastic rocks (andesite, volcanic sandstone and

siltstone, breccia, lava breccia, and pillow lava) of andesitic

composition. Large intrusions of plutonic rocks into the

volcanic strata occur in the Utuado area in west-central Puerto

Rico and in the San Lorenzo area in southeastern Puerto Rico.

These batholiths consist of granodiorite and quartz diorite.

Plutonic rocks crop out in many small areas throughout the

island. Ultrabasic rocks called serpentinite occur in the Cerro

Las Mesas, Monte del Estado, and Bosque de Susúa areas in

southwestern Puerto Rico. They formed in the late Jurassic

period, probably 150 million years ago. The present area of the

MLRA emerged from the sea during the early Tertiary period as

a result of uplift caused by plate tectonics. The uplift of the

island produced numerous fractures and fault zones and tilted

the originally horizontal strata.

Climate

The average annual precipitation is 80 to 85 inches (2,030

to 2,160 millimeters) in most of this area. It can be as low as 60

inches (1,525 millimeters) along the northern and southern

edges of the area and can be 120 to 200 inches (3,050 to 5,080

millimeters) at the highest elevations. Most of the rainfall

occurs in the afternoons as frequent, trade-wind showers from

May to October, but tropical storms and hurricanes can produce

high amounts of rain that can result in local flooding and

landslide problems. The area is typically drier from December

to March, rainy during April and May, semidry in June and July,

and wet from August to November. The average annual

temperature is less than 70 degrees F (21 degrees C) at the

higher elevations and 74 degrees F (23 degrees C) at the lower

elevations. There is little difference in air temperature between

the summer and winter seasons. This MLRA is freeze-free.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:
620 Major Land Resource Areas

Public supply—surface water, 88.9%; ground water, 7.2%

Livestock—surface water, 0.9%; ground water, 0.4%

Irrigation—surface water, 0.0%; ground water, 0.0%

Other—surface water, 0.9%; ground water, 1.6%

The total withdrawals average 30 million gallons per day

(115 million liters per day). About 9 percent is from ground

water sources, and 91 percent is from surface water sources.

Rainfall, perennial streams, and lakes provide ample amounts

of surface water. Manmade lakes are used to trap and store

runoff for public supply and irrigation at the lower elevations

outside this MLRA. The surface water generally meets the

recommended standards for all uses. Fecal coliform

contamination can occur at times in streams.

The ground water in this area is of good quality, but it is

little used. The principal aquifer is the dense and massive

volcanic rock underlying most of the area. Fractures and joints

in the rock trap and hold the water. Another source of ground

water consists of alluvial deposits of very limited extent in

narrow valleys.

Soils

The dominant soils in this MLRA are Inceptisols, Ultisols, or

Oxisols. The dominant suborders are Udepts, Humults, and

Udox. Most of the soils have an isohyperthermic or isothermic

soil temperature regime, a udic soil moisture regime, and mixed

mineralogy and are clayey or loamy. The soil moisture regime

in the Luquillo area is perudic. Shallow and moderately deep

Eutrudepts (Caguabo, Mucara, Quebrada, and Morado series)

are on steep side slopes, mainly in the east-central part of

Puerto Rico. Deep, very fine textured Haplohumults (Humatas

series) and Hapludox (Los Guineos series) are on steep side

slopes in the west-central part of Puerto Rico. Deep, extremely

weathered Acrudox (Nipe series) are of minor extent in the

western part of Puerto Rico.

Biological Resources

The dominant plant species in this area are carpetgrass,

whorled dropseed, pendejuelo, knotroot bristlegrass, creeping

wheatgrass, St. Augustine grass, woodland grass, foxtail grass,

beardgrass, matojito, flor de conchitas, bitterbrush, sensitive

plant, tick trefoil, burbrush, albizia tree, false moneywort, black

manzanilla, shepherdsneedle, black sage, rattleweed, wireweed,

boton blanco, wild sage, guava, coconut tree, flame tree, white

oak, turkey berry, camasey, higuillo, yagrumo hembra, yagrumo

macho, guano, tabonuco tree, mango tree, treefern, palma de

sierra, Christmas tree, Puerto Rico royal palm, palo de doncella,

and basora prieta.

Some of the major wildlife species in this area are Anolis

species, bananaquit, bridled quail dove, cattle egret,

Eleutherodactylus species, green-throated carib, Antillean

nighthawk, elfin woods warbler, gray kingbird, greater

Antillean grackle, killdeer, mangose (invasive), merlin, plain

pigeon, Puerto Rican boa, Puerto Rican bullfinch, Puerto Rican

emerald hummingbird, Puerto Rican lizard cuckoo, Puerto

Rican nightjar, Puerto Rican screech owl, Puerto Rican tanager,

Puerto Rican tody, Puerto Rican woodpecker, Puerto Rico

vireo, red-tailed hawk, rodents, ruddy quail dove, scaly-naped

pigeon, sharp-shined hawk, smooth-billed ani, and West Indian

whistling duck.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 23%

Grassland—private, 23%

Forest—private, 34%; Federal, 1%

Urban development—private, 14%

Water—private, 2%

Other—private, 3%

The grassland in the area is pasture that supports improved

forage and native grasses. Approximately 7 percent of the area

is used for the production of coffee beans. Most of the coffee

beans are grown in the shade, but some are grown in sunlight.

The food crops grown in the area include plantains, bananas,

taniers, yams, and pigeon peas. Orchard crops also are grown.

The climax vegetation in the area consists of forest species.

Urban expansion is becoming a serious land use problem in the

area.

The major soil resource concerns are water erosion (sheet

and rill and ephemeral gully or concentrated flow) and mass

movement of soil; maintenance of the content of organic

matter, tilth, and fertility of the soils; and water infiltration.

Water-quality concerns include surface water contaminants

derived from organic and inorganic fertilizers.

Conservation practices on cropland generally include

conservation crop rotations, contour farming, hillside ditches,

grassed waterways, crop residue management systems

(especially no-till systems), and nutrient and pest management.

Conservation practices on pasture generally include fencing,

pasture and hayland planting, watering facilities, and

prescribed grazing. 

271—Semiarid Mountains and Valleys

This area (shown in fig. 271-1) is in Puerto Rico (71

percent), the Virgin Islands (20 percent), and the outlying

islands of Vieques and Culebra (9 percent). It makes up about

525 square miles (1,365 square kilometers). From west to east,

the towns of Cabo Rojo, Lajas, Guanica, Yauco, Peñuelas, Juana

Díaz, Coamo, Salinas, Guayama, and Arroyo, Puerto Rico, are in

this area. All of St. John and St. Thomas and the towns of

Christiansted and Frederiksted, St. Croix, are in the area.
of the United States 621

Figure 271-1: Location of MLRA 271 in Land Resource Region Z.

Physiography

The part of this area in Puerto Rico consists of semiarid

mountains that form the southern slopes of the central

mountain chain (Cordillera Central), which extends from east to

west across the length of the island. Slopes generally range

from moderately steep to very steep. They are nearly vertical in

the northernmost part of the area. Elevation ranges from 160 to

1,300 feet (50 to 395 meters).

The part of this area in the Virgin Islands and in the two

outlying islands is mountainous. A ridge of mountains

characterizes the northeast and northwest corners of St. Croix.

Mount Eagle, the highest peak in St. Croix, is 1,165 feet (355

meters) high. St. Thomas and St. John are characterized by

irregular coastlines, many bays, steep slopes, and small

drainage areas. Crown Mountain, the highest peak in St.

Thomas, is 1,556 feet (474 meters) above sea level. Bordeaux

Mountain, the highest peak in St. John, is 1,297 feet (395

meters) above sea level.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Puerto Rico (2101), 71 percent; Virgin Islands (2102), 20

percent; and Caribbean Outlying Islands (2103), 9 percent. All

of the streams in the part of this area in Puerto Rico flow to the

south; none are perennial.

Geology

The geology of this MLRA is very diverse. The part of the

area in Puerto Rico consists of steep mountainsides composed

mainly of Cretaceous rocks. The lower mountains consist of

Tertiary limestone. Ultrabasic rocks (serpentinite) occur in

Sierra Bermeja, in southwestern Puerto Rico. Together with the

chert fragments in the same area, they constitute the oldest

rocks on the island. They formed in the late Jurassic period,

probably 150 million years ago. Most of the part of the MLRA

in Puerto Rico has a mixture of limestone and volcanic rocks in

the higher, steeper areas. Some igneous intrusives also occur in

the parts of the MLRA in Puerto Rico and the outlying islands.

Volcanic rocks are dominant, however, in the higher parts of the

Virgin Islands and the other outlying islands around Puerto

Rico.

Climate

The average annual precipitation in the part of this MLRA

in Puerto Rico is 35 to 45 inches (890 to 1,145 millimeters)

near the coast and is as much as 60 inches (1,525 millimeters)

in the higher inland areas. Much of the rainfall is lost through

evapotranspiration, and the year-round air temperatures are

high. Thus, the climate is semiarid. Most of the rainfall occurs

in the afternoons as frequent trade-wind showers from May to

October, but tropical storms and hurricanes can produce high

amounts of rain that can result in widespread flooding

problems. This part of the MLRA is typically drier from

December through March, rainy during April and May, semidry

in June and July, and wet from August through November.

The average annual precipitation in the part of this MLRA

on St. Croix is 40 to 50 inches (1,015 to 1,270 millimeters),

decreasing nearer the coast. St. Thomas is the driest of the

Virgin Islands. Its annual precipitation is 35 to 42 inches (890

to 1,065 millimeters). St. John is the wettest island. Its annual

precipitation is 40 to 55 inches (1,015 to 1,395 millimeters). No

records are kept on the annual precipitation in the outlying

islands. The annual amount on these islands is probably similar

to the amount on St. Croix.

The average annual temperature in this MLRA is about 79

degrees F (26 degrees C). The difference between the

temperature in summer and that in winter is less than 8 degrees

F (5 degrees C). This MLRA is freeze-free.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 53.6%; ground water, 33.4%

Livestock—surface water, 0.6%; ground water, 1.6%

Irrigation—surface water, 2.7%; ground water, 1.3%

Other—surface water, 0.8%; ground water, 6.0%

The total withdrawals average 75 million gallons per day

(285 million liters per day). About 42 percent is from ground

water sources, and 58 percent is from surface water sources.

Rainfall provides an ample supply of surface water in the part

of this area in Puerto Rico, but most of the precipitation is lost

through evapotranspiration before it can reach streams or the

ground water table. Manmade lakes are used to trap and store

runoff water for public supply and some irrigation. The area has

no perennial streams. Fecal coliform levels generally are high

during periods when the streams are flowing. During dry
622 Major Land Resource Areas

periods, the effluent from sewage treatment plants typically

makes up almost all of the flow in streams near population

centers.

The South Coastal Plains aquifer, one of the two most

important aquifers in Puerto Rico, underlies most of the

southern half of this MLRA. This alluvial deposit generally

holds calcium bicarbonate water. Along the coast, however, the

intrusion of saltwater changes the ground water to a sodium

chloride type. The surface water and ground water generally

meet the recommended standards for all uses. The ground water

is very hard, and the highest concentrations of nitrate on the

island occur in the South Coastal Plains aquifer. Nitrate levels

are still below the limit allowed in drinking water (10 parts per

million or milligrams per liter).

Alluvial deposits in valleys and volcanic rocks are the

primary sources of ground water in the northern half of the part

of this MLRA in Puerto Rico. Narrow valley floors and steep

volcanic rock slopes adjacent to the valleys limit the quantities

of available ground water in these two aquifers. Most of the

ground water used in this area is from the South Coastal Plains

aquifer.

In the part of this MLRA on the Virgin Islands and on the

outlying islands, streams do not flow throughout the year and

the amount of available ground water in the volcanic rocks is

low. Thus, the freshwater needs on these islands typically

exceed the annual supplies. Rooftop catchments and seawater

conversion plants are used to provide almost all of the potable

water on the islands. Contamination from sewage effluent and

septic systems creates water-quality problems.

The limited quantities of ground water in the volcanic rock

aquifers on the Virgin Islands are primarily used for domestic

purposes. This water is of better quality than the ground water

in the calcareous sediments of the King’s Hill aquifer

underlying the center of St. Croix. The levels of total dissolved

solids (especially chloride), nitrates, and bacteria from fecal

sources are much lower in the volcanic rock aquifer.

Soils

The dominant soils in the part of this MLRA in Puerto Rico

are Mollisols, Inceptisols, or Alfisols. The dominant suborders

are Ustolls and Ustepts. The soils have an isohyperthermic soil

temperature regime, an ustic soil moisture regime, and mixed

mineralogy. They are underlain by volcanic rocks. They

generally are shallow or moderately deep and are clayey. Well

drained, shallow Haplustolls (Descalabrado series) are

dominant throughout this part of the MLRA. Well drained,

moderately deep Dystrustepts (Callabo series) and Haplustolls

(Jacana series) are on side slopes and footslopes. Of minor

extent are shallow, well drained Haplustalfs (Guayama series)

on steep side slopes.

The dominant soils in the part of this MLRA in the Virgin

Islands are Mollisols or Inceptisols. The dominant suborders are

Ustolls and Ustepts. The soils have an isohyperthermic soil

temperature regime, an ustic soil moisture regime, and mixed

mineralogy. They are underlain by volcanic rocks. They

generally are shallow or moderately deep, well drained clay

loams. Haplustolls (Annaberg-Cramer complex and

Fredriksdal-Susannaberg complex) and Haplustepts (VictorySouthgate complex) are dominant throughout this part of the

MLRA.

Biological Resources

The dominant plant species in this MLRA are

hurricanegrass, guineagrass, Mexican bluegrass, buffelgrass,

southern sandbur, Egyptian grass, Kleberg’s bluestem, flame

tree, white oak, goosegrass, sprawling panic, wiregrass,

threeawn, coconut tree, slender gramagrass, lovegrass, coconut

paspalum, tamarind tree, sweet acacia, maga tree, whorled

dropseed, para grass, pata conejo, knotroot bristlegrass,

purslane, cockspur, sensitive plant, tautaba, mallow, butterfly

pea, century plant, leucaena, giant milkweed, croton, black

olive, turpentine, basora, rattlebox, mesquite, Christmas tree,

damiana, guayacan tree, and tantan.

Some of the major wildlife species in this area are Adelaide’s

warbler, barn swallow, Caribbean elaenia, cattle egret, iguana,

lesser Antillean pewee, lizards, Puerto Rican lizard cuckoo,

mourning dove, northern mockingbird, ovenbird, prairie

warbler, Puerto Rican nightjar, sparrow hawk, yellow-faced

grassquit, West quail dove, Puerto Rican bullfinch, greenthroated carib, brown pelican, common moorhen, masked duck,

Puerto Rican woodpecker, Puerto Rican emerald hummingbird,

Puerto Rican tody, Puerto Rico vireo (Bien-te-veo), Puerto

Rican flycatcher (Juí), yellow-shouldered blackbird (Mariquita

de Puerto Rico), and donkeys.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 4%

Grassland—private, 38%; Federal, 5%

Forest—private, 25%; Federal, 5%

Urban development—private, 16%

Water—private, 1%

Other—private, 5%; Federal, 1%

About 43 percent of the area is pasture, which supports

mainly adapted native grasses. About 30 percent is natural

forest; 8 percent supports improved species of such hardwoods

as mahogany, teak, and eucalyptus.

The mountainous region in northwestern St. Croix, the

largest of the Virgin Islands, supports a fairly dense tropical

forest. The other parts of the MLRA support a dense growth of

thorny bushes and cacti, which generally grow in semiarid

regions having low rainfall and high evaporation rates.
of the United States 623

Figure 272-1: Location of MLRA 272 in Land Resource Region Z.

Although the soils in the Virgin Islands have severe limitations

that preclude their use as sites for dwellings, urban

development is significant in this MLRA. Urban expansion is

becoming a land use problem.

The major soil resource concerns are water erosion (sheet

and rill and ephemeral gully or concentrated flow),

maintenance of the content of organic matter and tilth of the

soils, and water infiltration. Water-quality concerns include

surface water contaminants derived from organic and inorganic

fertilizers. Water-quantity concerns include water management

on irrigated land.

Conservation practices on cropland generally include

conservation crop rotations, contour farming, grassed

waterways, crop residue management systems (especially no-till

systems), and nutrient and pest management. Conservation

practices on pasture generally include fencing, pasture and hay

planting, watering facilities, and prescribed grazing. 

272—Humid Coastal Plains

This MLRA is primarily on the northern coast of Puerto

Rico, but it includes small areas on the east and west coasts (fig.

272-1). It makes up about 965 square miles (2,500 square

kilometers). From west to east, the cities of Isabela,

Quebradillas, Camuy, Hatillo, Arecibo, Barceloneta, Manati,

Dorado, Toa Baja, Toa Alta, Bayamón, Guaynabo, San Juan,

Carolina, and Loíza are in the part of this MLRA on the

northern coast. The cities of Aguadilla and Mayagüez are in the

part on the west coast, and the cities of Fajardo and Ceiba are in

the part on the east coast. More than half of Puerto Rico’s

population lives in this MLRA. Puerto Rico State Road 2

connects San Juan and Mayagüez, and Puerto Rico State Road

3 connects San Juan and Ceiba. The “Expreso de Diego,”

Puerto Rico Highway 22, connects San Juan and Arecibo.

Physiography

This area is divided into two distinct zones. One zone

consists of the flat alluvial plains and terraces along the coast,

and the second consists of the irregular features of karst

limestone in inland areas. In the northwest corner of the MLRA,

limestone forms a sharp cliff rising almost 200 feet (60 meters) a

short distance inland from the beach. In the rest of the area, the

karst is eroded and is expressed as either low, rolling hills or

steep-sided, isolated hills. Longitudinal depressions parallel

the coast from Arecibo to Sabana Seca. Swamps and lagoons

have developed in these depressions. Elevation ranges from sea

level to 2,300 feet (0 to 700 meters).

The only major Hydrologic Unit Area (identified by a fourdigit number) that makes up this MLRA is Puerto Rico (2101).

Streams generally flow to the north in this area. Most of the

drainage in the karst zone is underground.

Geology

The mountainous part of this MLRA consists of a series of

limestone formations that originated in a marine basin north of

the island during the Oligocene to Miocene epoch of the

Tertiary period (30 to 15 million years ago). After the uplift of

these sediments to their present elevation, dissolution of the

calcareous rocks produced a distinct karst topography. The

limestones of the north coast account for nearly one-fifth of

Puerto Rico’s land area.

The flat part of this MLRA consists of various alluvial

sediments of Quaternary age. The most extensive of these are

the so-called “Blanket Deposits,” which developed during the

late Tertiary and early Quaternary as a result of the erosion of

the interior of the island following the uplift. These deposits

consist of sand, silt, and clay in various proportions.

The small areas on the east and west coasts are made up of

alluvial flood plains and wave-cut coastal terraces that consist

of river alluvium. Lower lying swamps and marshes are near the

coast and adjacent to many of the larger rivers. An extensive

swampy area is east of Arecibo on the north coast.

Climate

The average annual precipitation in most of this area is 60 to

65 inches (1,525 to 1,650 millimeters), increasing with

elevation. Most of the rainfall occurs in the afternoons as

frequent, trade-wind showers from May to October, but tropical

storms and hurricanes can produce high amounts of rain that

can result in local flooding and landslide problems. The area is

typically drier from December through March, rainy during

April and May, semidry in June and July, and wet from August

through November. The average annual temperature is about 77

degrees F (25 degrees C). There is little difference in air
624 Major Land Resource Areas

temperature between the summer and winter seasons. This

MLRA is freeze-free.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 66.8%; ground water, 15.3%

Livestock—surface water, 0.7%; ground water, 0.9%

Irrigation—surface water, 6.4%; ground water, 5.7%

Other—surface water, 0.7%; ground water, 3.6%

The total withdrawals average 265 million gallons per day

(1,005 million liters per day). About 25 percent is from ground

water sources, and 75 percent is from surface water sources.

Rainfall and perennial streams provide ample supplies of

surface water in this area. Manmade lakes are used to trap and

store runoff water for cooling hydroelectric power plants and

for public supply at the lower elevations in this area. The

surface water generally is of good quality, meeting the

recommended standards for drinking water. Most of the streams

near population centers are contaminated with fecal coliform.

Also, most sewage treatment plants discharge partially treated

effluent into streams during most of the year. These discharges

generally occur near the coast.

The North Coast Limestone is one of the most heavily used

aquifers on the island. Ample supplies of ground water in this

aquifer are generally of good quality. Both the water table and

artesian water meet the recommended standards for drinking

water. The calcium bicarbonate type of water in the water table

aquifer can change to a sodium chloride type near the coast

because of the intrusion of saltwater. The higher levels of

chloride typically exceed the recommended limits for total

dissolved solids for drinking water. The hydrodynamic pressure

in the artesian aquifer provides a positive flow of freshwater

into the ocean at some distance offshore, so there is no chloride

contamination in this deeper aquifer.

The alluvial valley deposits on the east and west coasts are

another source of ground water in this area. The level of total

dissolved solids in the West Coast alluvial valley aquifer is

much higher than the recommended level for drinking water.

The intrusion of seawater is a major problem in this aquifer. The

level of total dissolved solids in the East Coast alluvial valley

aquifer is not much higher than the level in the North Coast

limestone aquifer. The water in the East Coast alluvial valley

aquifer is suitable only for irrigation and livestock, however,

because of high levels of iron and manganese, from volcanic

rocks and ancient swamp deposits.

Soils

The soils in this MLRA include a wide range of Ultisols,

Inceptisols, Entisols, Histosols, Oxisols, Mollisols, and Alfisols.

All of the soils in the area have an isohyperthermic soil

temperature regime, most have an ustic soil moisture regime,

and most are clayey and have mixed or kaolinitic mineralogy.

There are four distinct geomorphic areas in this MLRA—

coastal plains, flood plains along rivers, small lagoon-like

depressions, and areas of limestone karst. On the coastal plains,

the dominant soils are Ultisols or Oxisols and the dominant

suborders are deep, well drained Udults or Udox. On the flood

plains, the dominant soils are Mollisols or Inceptisols and the

dominant suborders are poorly drained Aquolls, somewhat

poorly drained Aquepts, or well drained Udolls. In the small

depressions, the dominant soils are Histosols or Entisols and

the dominant suborders are poorly drained Saprists or Aquents.

Miscellaneous areas of swamps and marshes are in these

depressions. In the extensive areas of limestone karst, the

dominant soils are Mollisols or Alfisols and the dominant

suborders are Rendolls, Udolls, or Udalfs.

Biological Resources

The dominant plant species in this area are Caribgrass,

streambank millet, para grass, beach sedge, Durban crowfoot

grass, Jamaica fingergrass, lovegrass, flame tree, white oak,

beachgrass, St. Augustine grass, carpetgrass, southern sandbur,

knotroot bristlegrass, albizia tree, bayhops, seapurslane, Puerto

Rico royal palm, wireweed, coconut tree, stargrass,

pangolagrass, Venezuela grass, Kleberg’s bluestem, Tanner

grass, Napier grass, signalgrass, and guineagrass. The dominant

vegetation on wetlands includes red mangrove, white

mangrove, black mangrove, button mangrove, southern cattail,

leatherfern, and para grass.

Some of the major wildlife species in this area include

bananaquit, zenaida dove, smooth-billed ani, Puerto Rican

lizard cuckoo, lesser Antillean pewee, yellow warbler, cave

swallow, white-crowned pigeon, barn swallow, cattle egret,

great egret (Garza real), green heron (Martinete), little blue

heron, northern waterthrush, West India whistling duck, whiterumped sandpiper, semipalmated sandpiper, least sandpiper,

greater yellowlegs, Wilson’s plover, yellow-crowned nightheron, blue-winged teal, and white-cheeked pintail.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 7%

Grassland—private, 24%

Forest—private, 27%; Federal, 2%

Urban development—private, 33%

Water—private, 2%

Other—private, 5%

Most of this area is in farms averaging 35 acres (14 hectares)

in size. The pastures in the area support native and improved

grasses. Many large dairy farms are in the area. The cropland in

the MLRA includes about 3,000 acres (1,215 hectares) of
of the United States 625

Figure 273-1: Location of MLRA 273 in Land Resource Region Z.

farmland of statewide importance, which is planted to

pineapples and is in areas of Oxisols. Many areas that formerly

were used for sugarcane are now used for hayland or sod

grasses. Orchards, consisting mainly of orange and grapefruit

trees, are important in some areas. Urban development is

significant, especially in areas adjacent to large metropolitan

centers. It is a serious land use problem because it results in the

loss of prime farmland.

The major soil resource concerns are water erosion (sheet

and rill); maintenance of the content of organic matter, tilth,

and fertility of the soils; crusting; and water infiltration. Waterquality concerns include surface water contaminants derived

from organic and inorganic fertilizers. Water-quantity concerns

include runoff, flooding, and water management on

nonirrigated land.

Conservation practices on cropland generally include

conservation crop rotations, bedding, deep tillage, grassed

waterways, crop residue management systems (especially no-till

systems), and nutrient and pest management. Conservation

practices on pasture generally include fencing, pasture and hay

planting, watering facilities, and prescribed grazing. 

273—Semiarid Coastal Plains

This area (shown in fig. 273-1) is on the south coast of

Puerto Rico (81 percent) and mostly on the southern side of St.

Croix in the Virgin Islands (10 percent) and the outlying islands

of Vieques, Desecheo, and Mona (9 percent). It makes up about

305 square miles (785 square kilometers). The part of the area

on St. Croix is 28 square miles (72 square kilometers). The

MLRA includes the towns of Cabo Rojo, Lajas, Guanica,

Ponce, Juana Díaz, Salinas, Guayama, and Arroyo, Puerto Rico;

Hamilton, St. Croix; and Isabel Segunda, Vieques. The Puerto

Rico National Guard Camp (Campamento Santiago) is at the

eastern end of the area, and a number of State parks are in the

area, primarily on the coast in Puerto Rico.

Physiography

The coastal half of the part of this area in Puerto Rico gently

slopes up from the Caribbean Sea. Most of the towns are at an

elevation of 5 to 50 feet (2 to 15 meters). The inland half of the

MLRA rises sharply to an elevation of 250 feet (75 meters).

Steep foothills are at the base of the southern slopes of the

central mountain chain (Cordillera Central), which extends

from east to west across the length of the island. The part of the

area in the “Valle de Lajas” is a flat coastal plain surrounded by

steep foothills on three sides.

A rolling plain marks the part of this area on St. Croix. It

generally is at an elevation of 10 to 140 feet (3 to 45 meters). It

is flatter on the coast and more rolling in inland areas. The

MLRA extends to the coast on both the south and north sides

of the eastern end of St. Croix. Elevation rises to almost 200

feet (60 meters) in the area connecting the northern and

southern parts of this MLRA. The MLRA separates two

mountainous areas on the north side of the island.

The extent of the major Hydrologic Unit Areas (identified by

four-digit numbers) that make up this MLRA is as follows:

Puerto Rico (2101), 81 percent; Virgin Islands (2102), 10

percent; and Caribbean Outlying Islands (2103), 9 percent. In

the “Valle de Lajas,” the main river flows west, but all of the

other streams in the part of this MLRA in Puerto Rico flow

south. None of the streams in the MLRA are perennial.

Geology

The geology of this MLRA is very similar to that of the low

part of MLRA 271. An important feature is the Lajas Valley,

which formed in a geosyncline. This low area was produced by

a deeper lying graben or down-dropped block between two

gravity faults. This valley is in the western part of the MLRA,

south of the footslopes of the Cordillera Central and north of

the Sierra Bermeja. It is filled with as much as 240 feet (75

meters) or more of clayey sediments.

Gravel, sands, silts, and clays deposited in the Quaternary

period by rivers typically occur on the flatter parts of this

MLRA near the coast. Limestone and volcanic rocks occur in

the higher, steeper parts. The flatter alluvial deposits are not

very extensive. Of all the Virgin Islands, St. Croix is the only

one in which limestone occurs as parent material. Volcanic

rocks form the interior and higher parts of the Virgin Islands and

the other outlying islands around Puerto Rico.

Climate

The average annual precipitation in most of this area is 30 to

45 inches (760 to 1,145 millimeters). It is lower near the coast

and higher on the inland hills. It is 10 to 30 inches (255 to 760

millimeters) in a few small, isolated areas. Almost all of the

rainfall is lost through evapotranspiration, and the year-round
626 Major Land Resource Areas

air temperatures are high. Thus, the climate is semiarid. Most of

the rainfall occurs in the afternoons as frequent, trade-wind

showers from May to October, but tropical storms and

hurricanes can produce high amounts of rain that can result in

widespread flooding problems. The area typically is drier from

December through March, rainy during April and May, semidry

in June and July, and wet from August through November. The

average annual temperature is about 79 degrees F (26 degrees

C). The variation in mean monthly temperatures is only 5 to 8

degrees F (3 to 4 degrees C). This MLRA is freeze-free.

Water

Following are the estimated withdrawals of freshwater by use

in this MLRA:

Public supply—surface water, 38.5%; ground water, 10.0%

Livestock—surface water, 0.5%; ground water, 0.6%

Irrigation—surface water, 30.4%; ground water, 17.0%

Other—surface water, 1.2%; ground water, 1.9%

The total withdrawals average 225 million gallons per day

(850 million liters per day). About 30 percent is from ground

water sources, and 70 percent is from surface water sources.

Rainfall provides an ample supply of surface water in the part

of this area in Puerto Rico, but 90 percent of the precipitation is

lost through evapotranspiration before it can reach streams or

the ground water table. Manmade lakes are used to trap and

store runoff water for public supply and some irrigation. The

area has no perennial streams. Fecal coliform levels generally

are high during periods when the streams are flowing. During

dry periods, the effluent from sewage treatment plants typically

makes up almost all of the flow in streams near population

centers.

The South Coastal Plains aquifer, one of the two most

important aquifers in Puerto Rico, underlies this MLRA. This

alluvial deposit generally holds calcium bicarbonate water.

Along the coast, however, the intrusion of saltwater changes the

ground water to a sodium chloride type. The surface water and

ground water generally meet the recommended standards for all

uses. The ground water is very hard, and the highest

concentrations of nitrate occur in the South Coastal Plains

aquifer. Nitrate levels are still below the limit allowed for

drinking water (10 parts per million or milligrams per liter).

The West Coast alluvial valley aquifer underlies the “Valle

de Lajas.” The water from this aquifer is generally of good

quality, except for very high levels of total dissolved solids.

The water is normally a calcium bicarbonate type, but it is a

sodium chloride type near the coast, where seawater intrusion is

common.

The Virgin Islands use almost 11 million gallons of

freshwater per day (42 million liters per day). About 90 percent

of this water is used in the part of this MLRA on the island of

St. Croix. Almost all of the water is used for public supply.

Streams do not flow throughout the year, and the amount of

available ground water is low. Thus, the needs for freshwater in

the Virgin Islands typically exceed the annual supplies.

Rooftop catchments and seawater conversion plants are used to

provide almost all of the potable water on St. Croix and

Vieques. Contamination from sewage effluent and septic

systems can create water-quality problems.

Little ground water is used in the Virgin Islands. Most of the

ground water that is used comes from the calcareous sediments

of the King’s Hill aquifer underlying the center of St. Croix.

This alluvial deposit generally holds calcium bicarbonate

water. Near the coast, however, the intrusion of saltwater

changes the ground water to a sodium chloride type. The water

in this aquifer exceeds the drinking water standards for total

dissolved solids and chloride and is very hard. It is typically

desalinized before it is used as potable water. The levels of

nitrates, fecal coliform, and fecal streptococci bacteria

commonly exceed drinking water standards. Limited quantities

of ground water occur in the fractures and joints in the volcanic

rocks on Vieques.

Soils

The soils in this MLRA are dominantly Mollisols or

Vertisols. The soils in the part of the area in Puerto Rico have

an isohyperthermic soil temperature regime and generally have

an ustic soil moisture regime. They generally are clayey or

loamy and have mixed or smectitic mineralogy. In a small area

around Ensenada, the soils have an aridic soil moisture regime.

The dominant suborders on the flood plains are very deep,

somewhat poorly drained Aquolls and excessively drained and

well drained Ustolls. The dominant suborders on high terraces

are deep, expansive clayey Usterts and Aquerts.

The soils in the part of the area on St. Croix have an

isohyperthermic soil temperature regime and an ustic soil

moisture regime. They generally are clayey or gravelly loam

and have mixed or carbonatic mineralogy. The dominant

suborders on alluvial fans and terraces are well drained Ustolls

and Usterts. The dominant suborders on marine terraces and in

valleys in the limestone hills and mountains are clayey and

loamy Ustolls.

Biological Resources

The dominant plant species in this area are beachgrass,

southern sandbur, saltwort, bermudagrass, Mexican bluegrass,

Egyptian grass, matojo de piramide, whorled dropseed,

lovegrass, knotroot bristlegrass, sea purslane, heliotrope,

chickweed, lechecillo, tautaba, tuna cactus, bayhops, sweet

acacia, flame tree, white oak, leucaena, black olive, turpentine,

catclaw blackbead, twisted grass, coconut tree, buffer grass,
of the United States 627

guineagrass, Kleberg’s bluestem, and mesquite. The dominant

vegetation on wetlands includes red mangrove, white

mangrove, black mangrove, button mangrove, southern cattail,

leatherfern, water panicum, and para grass.

Some of the major wildlife species in this area include

yellow warbler, cattle egret, lesser woodpecker, Antillean

nighthawk, bananaquit, black-bellied plover, Blackpoll

warbler, black-whiskered vireo, blue-winged teal, brown

pelican, cave swallow, clapper rail, common ground-dove,

common moorhen, common yellowthroat, great blue heron,

great egret, greater Antillean grackle, greater yellowlegs, green

heron, killdeer, least sandpiper, lesser yellowlegs, little blue

heron, mangrove cuckoo, northern mockingbird, ovenbird,

prairie warbler, semipalmated plover, semipalmated sandpiper,

snowy egret, snowy plover, stilt sandpiper, tricolored heron,

white-cheeked pintail, white-crowned pigeon, Wilson’s plover,

and yellow-shouldered blackbird.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 20%

Grassland—private, 27%; Federal, 8%

Forest—private, 6%; Federal, 1%

Urban development—private, 23%

Water—private, 5%

Other—private, 10%

The pastures in this area support native and improved

grasses and are used mainly for beef production. The

production of hay for racehorses is an important enterprise in

some areas. About 38,000 acres (15,380 hectares) is irrigated by

different systems and is used mainly for pasture, hay, plantains,

or bananas. Several hundred acres are irrigated by drip systems

and are used for the production of avocados, mangos, or

oranges. The production of irrigated vegetables is of local

economic importance. Rapid urban expansion is a land use

problem near the larger cities of Puerto Rico. It has increased

the need for new roads, schools, recreational developments, and

agricultural land.

For many years, sugarcane grown on St. Croix was an

important part of the economy, but the sugar mills have been

closed. Finding a suitable cash crop has been difficult because

of the scarcity of water for irrigation. Approximately 13,665

acres (5,525 hectares) in the Virgin Islands, or 16 percent of the

total area, is used for agricultural purposes. Most of this acreage

is on St. Croix. More than 78 percent of the acreage is pasture

that is grazed by livestock. The main crops are herbs and spices,

sugarcane, coconuts, sweet potatoes, yams, and cassava. The

commonly grown vegetable crops include cucumbers,

eggplant, okra, peppers, and tomatoes. Avocados, bananas,

papayas, soursop, sugar apple, guavaberry, citrus fruits, and

mangos are the main fruit crops grown on the islands.

The major soil resource concerns in this MLRA are water

erosion (sheet and rill) induced by irrigation, surface

compaction, maintenance of the content of organic matter and

tilth of the soils, and water infiltration. Water-quality concerns

include surface water contaminants derived from organic and

inorganic fertilizers. Water-quantity concerns include runoff,

flooding, and water management on irrigated land. In the Virgin

Islands, limited supplies of soil moisture and ground water,

drought, and poor water quality are serious concerns.

Conservation practices on cropland generally include

conservation crop rotations, bedding, deep tillage, grassed

waterways, crop residue management systems (especially no-till

systems), nutrient and pest management, and irrigation water

management. Conservation practices on pasture generally

include fencing, pasture and hay planting, watering facilities,

and prescribed grazing. 

629

References

Cleland, D.T., J.A. Freeouf, J.E. Keys, G.J. Nowacki, C.A. Carpenter, and W.H. McNab. 2005.

Ecological subregions: Sections and subsections of the conterminous United States. U.S.

Department of Agriculture, Forest Service. Map.

Fenneman, N.M., and D.W. Johnson. 1946. Physical divisions of the United States. U.S.

Geological Survey map.

Hutson, S.S., N.L. Barber, J.F. Kenny, K.S. Linsey, D.S. Lumia, and M.A. Maupin. 2004.

Estimated use of water in the United States in 2000. U.S. Geological Survey Circular 1268.

McNab, W.H., D.T. Cleland, J.A. Freeouf, J.E. Keys, G.J. Nowacki, and C.A. Carpenter. 2005.

Description of ecological subregions: Sections of the conterminous United States. U.S.

Department of Agriculture, Forest Service.

Moody, D.W., E.B. Chase, and D.A. Aronson, compilers. 1986. National water summary

1985—Hydrologic events and surface water resources. U.S. Geological Survey Water-Supply

Paper 2300.

Moody, D.W., E.B. Chase, J. Carr, and R.W. Paulson, compilers. 1988. National water

summary 1986—Hydrologic events and ground-water quality. U.S. Geological Survey WaterSupply Paper 2325.

Omernik, J.M. 1987. Ecoregions of the conterminous United States. Map. Annals of the

Association of American Geographers 77(1): 118-125.

Seaber, P.R., F.P. Kapinos, and G.L. Knapp. 1984. State hydrologic unit maps. U.S. Geological

Survey Open-File Report 84-708.

Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S.

Department of Agriculture Handbook 18. http://soils.usda.gov/technical/

Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making and

interpreting soil surveys. 2nd edition. Natural Resources Conservation Service. U.S.

Department of Agriculture Handbook 436. http://soils.usda.gov/technical/

Solley, W.B., E.B. Chase, and W.B Mann IV. 1983. Estimated use of water in the United States

in 1980. U.S. Geological Survey Circular 1001.

Solley, W.B., R.R. Pierce, and H.A. Perlman. 1993. Estimated use of water in the United States

in 1990. U.S. Geological Survey Circular 1081.

United States Department of Agriculture, Natural Resources Conservation Service. National

soil survey handbook, title 430-VI. http://soils.usda.gov/technical/
630

United States Department of Agriculture, Natural Resources Conservation Service. 1997.

National resources inventory for the United States. Unpublished spreadsheet file.

United States Department of Agriculture, Soil Conservation Service. 1981. Land resource

regions and major land resource areas of the United States. U.S. Department of Agriculture

Handbook 296. http://soils.usda.gov/survey/geography/mlra/

United States Department of the Interior. 1973. Major ecosystems of Alaska. Joint FederalState Land Use Planning Commission, U.S. Geological Survey map.

United States Environmental Protection Agency. 1998. Water-quality criteria and standards

plan—priorities for the future. USEPA 822-R-98-003. U.S. Environmental Protection Agency,

Office of Water, Washington, DC.

United States Environmental Protection Agency. 2003. Level III ecoregions of the

conterminous United States. Revised from Omernik, 1987. USEPA National Health and

Environmental Effects Research Laboratory (NHEERL). http://www.epa.gov/wed/pages/

ecoregions/level_iii.htm

Wahrhaftig, C. 1965. Physiographic divisions of Alaska. U.S. Geological Survey Professional

Paper 482.
631

Glossary

Aa. A Hawaiian term for lava flows that typically have a rough,

jagged, spinose, clinkery surface.

Alluvial fan. A low, outspread mass of loose materials and/or

rock material, commonly with gentle slopes. It is shaped

like an open fan or a segment of a cone. The material was

deposited by a stream at the place where it issues from a

narrow mountain valley or upland valley or where a

tributary stream is near or at its junction with the main

stream. The fan is steepest near its apex, which points

upstream, and slopes gently and convexly outward

(downstream) with a gradual decrease in gradient.

Alluvium. Unconsolidated material, such as gravel, sand, silt,

clay, and various mixtures of these, deposited on land by

running water.

Aquifer. A geologic formation, group of formations, or part of a

formation that contains sufficient saturated permeable

material to yield significant quantities of water to wells or

springs.

Artesian well. A well tapping a confined aquifer in which the

static water level is above the top of the aquifer; a flowing

artesian well is a well in which the water level is above the

land surface.

Aspect. The direction toward which a slope faces. Also called

slope aspect.

Backslope. The position that forms the steepest and generally

linear, middle portion of a hillslope. In profile, backslopes

are commonly bounded by a convex shoulder above and a

concave footslope below.

Backswamp. A flood-plain landform. Extensive, marshy or

swampy, depressed areas of flood plains between natural

levees and valley sides or terraces.

Badland. A landscape that is intricately dissected and

characterized by a very fine drainage network with high

drainage densities and short, steep slopes and narrow

interfluves. Badlands develop on surfaces that have little

or no vegetative cover overlying unconsolidated or poorly

cemented materials (clays, silts, or sandstones) with, in

some cases, soluble minerals, such as gypsum or halite.

Basal ground water. A term that originated in Hawaii and refers

to a major body of fresh ground water in contact

with underlying saline water (usually seawater in Hawaii

and the Pacific Basin) in the lowermost part of the flow

system.

Base flow. The sustained low flow of a stream. In some areas

base flow is the ground-water inflow to the stream

channel.

Bedrock. The solid rock that underlies the soil and other

unconsolidated material or that is exposed at the surface.

Bedrock-controlled topography. A landscape where the

configuration and relief of the landforms are determined or

strongly influenced by the underlying bedrock.

Bolson. Extensive, flat, saucer-shaped, alluvium-floored basin

or depression, almost completely or completely surrounded

by mountains and from which drainage has no outlet; a

term used in desert regions in the southwestern part of the

United States.

Bottom land. An informal term loosely applied to various

portions of a flood plain.

Boulders. Rock fragments larger than 2 feet (60 centimeters) in

diameter.

Breaks. A landscape or tract of steep, rough or broken land

dissected by ravines and gullies and marking a sudden

change in topography.

Butte. An isolated, generally flat-topped hill or mountain with

relatively steep slopes and talus or precipitous cliffs and

characterized by summit width that is less than the height

of bounding escarpments; commonly topped by a caprock

of resistant material and representing an erosion remnant

carved from flat-lying rocks.

Caliche. A general term for a prominent zone of secondary

carbonate accumulation in surficial materials in warm,

subhumid to arid areas. Caliche is formed by both geologic

and pedologic processes. Finely crystalline calcium

carbonate forms a nearly continuous surface-coating and

void-filling medium in geologic (parent) materials.

Cementation ranges from weak in nonindurated forms to

very strong in indurated forms. Other minerals (e.g.,

carbonates, silicate, and sulfate) may occur as accessory

cements. Most petrocalcic horizons and some calcic

horizons are caliche.

Canyon. A long, deep, narrow valley with high, precipitous

walls in an area of high local relief.

Cirque. A steep-walled, semicircular or crescent-shaped, halfbowl-like recess or hollow, commonly situated at the head

of a glaciated mountain valley or high on the side of a

mountain. It was produced by the erosive activity of a
632 Major Land Resource Areas

mountain glacier. It commonly contains a small round lake

(tarn).

Clay. As a soil separate, the mineral soil particles less than

0.002 millimeter in diameter. As a soil textural class, soil

material that is 40 percent or more clay, less than 45

percent sand, and less than 40 percent silt.

Claypan. A dense, compact, slowly permeable subsoil layer

that contains much more clay than the overlying materials,

from which it is separated by a sharply defined boundary. A

claypan is commonly hard when dry and plastic and sticky

when wet.

Coarse textured soil. Sand or loamy sand.

Cobble (or cobblestone). A rounded or partly rounded fragment

of rock 3 to 10 inches (7.6 to 25 centimeters) in diameter.

Colluvium. Unconsolidated, unsorted earth material being

transported or deposited on side slopes and/or at the base

of slopes by mass movement (e.g., direct gravitational

action) and by local, unconcentrated runoff.

Conglomerate. A coarse grained, clastic sedimentary rock

composed of rounded or subangular rock fragments more

than 2 millimeters in diameter. It commonly has a matrix of

sand and finer textured material. Conglomerate is the

consolidated equivalent of gravel.

Conservation cropping system. Growing crops in combination

with needed cultural and management practices. In a good

conservation cropping system, the soil-improving crops

and practices more than offset the effects of the soildepleting crops and practices. Cropping systems are

needed on all tilled soils. Soil-improving practices in a

conservation cropping system include the use of rotations

that contain grasses and legumes and the return of crop

residue to the soil. Other practices include the use of green

manure crops of grasses and legumes, proper tillage,

adequate fertilization, and weed and pest control.

Conservation tillage. A tillage system that does not invert the

soil and that leaves a protective amount of crop residue on

the surface throughout the year.

Contour stripcropping. Growing crops in strips that follow the

contour. Strips of grass or close-growing crops are

alternated with strips of clean-tilled crops or summer

fallow.

Cover crop. A close-growing crop grown primarily to improve

and protect the soil between periods of regular crop

production, or a crop grown between trees and vines in

orchards and vineyards.

Crop residue management. Returning crop residue to the

soil. This practice helps to maintain soil structure,

organic matter content, and fertility and helps to control

erosion.

Cropping system. Growing crops according to a planned

system of rotation and management practices.

Cross-slope farming. Deliberately conducting farming

operations on sloping farmland in such a way that tillage is

across the general slope.

Delta. A body of alluvium having a surface that is fan shaped

and nearly flat; deposited at or near the mouth of a river or

stream where it enters a body of relatively quiet water,

generally a sea or lake.

Depth, soil. Generally, the thickness of the soil over bedrock.

Very deep soils are more than 60 inches deep over bedrock;

deep soils, 40 to 60 inches; moderately deep, 20 to 40

inches; shallow, 10 to 20 inches; and very shallow, less

than 10 inches.

Desert pavement. A natural, residual concentration or layer of

wind-polished, closely packed gravel, boulders, and other

rock fragments mantling a desert surface. It forms where

wind action and sheetwash have removed all smaller

particles or where rock fragments have migrated upward

through sediments to the surface. It typically protects the

finer grained underlying material from further erosion.

Domestic water use. Use of water for all indoor household

purposes, such as drinking, food preparation, bathing,

washing clothes and dishes, and flushing toilets, and for

such outdoor purposes as watering lawns and gardens.

Drainage class (natural). Refers to the frequency and duration

of wet periods under conditions similar to those under

which the soil formed. Alterations of the water regime by

human activities, either through drainage or irrigation, are

not a consideration unless they have significantly changed

the morphology of the soil. Seven classes of natural soil

drainage are recognized—excessively drained, somewhat

excessively drained, well drained, moderately well

drained, somewhat poorly drained, poorly drained, and

very poorly drained. These classes are defined in the “Soil

Survey Manual.”

Drainage, surface. Runoff, or surface flow of water, from an

area.

Drainageway. A general term for a course or channel along

which water moves in draining an area. A term restricted to

relatively small, linear depressions that at some time move

concentrated water and either do not have a defined

channel or have only a small defined channel.

Draw. A small stream valley that generally is shallower and

more open than a ravine or gulch and that has a broader

bottom. The present stream channel may appear inadequate

to have cut the drainageway that it occupies.

Drift. A general term applied to all mineral material (clay, silt,

sand, gravel, and boulders) transported by a glacier and

deposited directly by or from the ice or transported by

running water emanating from a glacier. Drift includes

unstratified material (till) that forms moraines and stratified

deposits that form outwash plains, eskers, kames, varves,
of the United States 633

and glaciofluvial sediments. The term is generally applied

to Pleistocene glacial deposits in areas that no longer

contain glaciers.

Drinking water standard. The level of a dissolved constituent

in water that is deemed safe for human consumption. For

example, the national standard for drinking water is less

than 1,000 parts per million (milligrams per liter) total

dissolved solids. The secondary standard is 500 parts per

million (milligrams per liter). Secondary water quality

standards are for esthetics. Water exceeding the secondary

standard is safe but is less desirable for drinking and for

many industrial uses.

Drumlin. A low, smooth, elongated oval hill, mound, or ridge

of compact till that has a core of bedrock or drift. It

commonly has a blunt nose facing the direction from

which the ice approached and a gentler slope tapering in

the other direction. The longer axis is parallel to the

general direction of glacier flow. Drumlins are products of

streamline (laminar) flow of glaciers, which molded the

subglacial floor through a combination of erosion and

deposition.

Dune. A low mound, ridge, bank, or hill of loose, windblown

granular material (generally sand), either barren and

capable of movement from place to place or covered and

stabilized with vegetation but retaining its characteristic

shape.

Eolian deposit. Sand-, silt-, or clay-sized clastic material

transported and deposited primarily by wind, commonly in

the form of a dune or a sheet of sand or loess.

Erosion. The wearing away of the land surface by water, wind,

ice, or other geologic agents and by such processes as

gravitational creep.

Erosion (geologic). Erosion caused by geologic processes

acting over long geologic periods and resulting in the

wearing away of mountains and the building up of such

landscape features as flood plains and coastal plains.

Synonym: natural erosion.

Erosion (accelerated). Erosion much more rapid than

geologic erosion, mainly as a result of human or animal

activities or of a catastrophe in nature, such as a fire, that

exposes the surface.

Escarpment. A relatively continuous and steep slope or cliff

breaking the general continuity of more gently sloping

land surfaces and resulting from erosion or faulting. Most

commonly applied to cliffs produced by differential

erosion. Synonym: scarp.

Esker. A long, narrow, sinuous, steep-sided ridge of stratified

sand and gravel deposited as the bed of a stream flowing in

an ice tunnel within or below the ice (subglacial) or

between ice walls on top of the ice of a wasting glacier and

left behind as high ground when the ice melted. Eskers

range in length from less than1,000 feet to more than 100

miles (less than a kilometer to more than 160 kilometers)

and in height from 10 to 100 feet (3 to 30 meters).

Fallow. Cropland left idle in order to restore productivity

through accumulation of moisture. Summer fallow is

common in regions of limited rainfall where cereal grain is

grown. The soil is tilled for at least one growing season for

weed control and decomposition of plant residue.

Fan remnant. A general term for landforms that are the

remaining parts of older fan landforms, such as alluvial

fans, that have been either dissected or partially buried.

Fertility, soil. The quality that enables a soil to provide plant

nutrients, in adequate amounts and in proper balance, for

the growth of specified plants when light, moisture,

temperature, tilth, and other growth factors are favorable.

Fine textured soil. Sandy clay, silty clay, or clay.

Firebreak. An area cleared of flammable material to stop or

help control creeping or running fires. It also serves as a

line from which to work and to facilitate the movement of

firefighters and equipment. Designated roads also serve as

firebreaks.

Flood plain. The nearly level plain that borders a stream and is

subject to flooding unless protected artificially.

Fluvial. Of or pertaining to rivers or streams; produced by

stream or river action.

Foothills. A region of steeply sloping hills that fringes a

mountain range or high-plateau escarpment. The hills have

relief of as much as 1,000 feet (300 meters).

Footslope. The concave surface at the base of a hillslope. A

footslope is a transition zone between upslope sites of

erosion and transport (shoulders and backslopes) and

downslope sites of deposition (toeslopes).

Forb. Any herbaceous plant not a grass or a sedge.

Forest type. A stand of trees similar in composition and

development because of given physical and biological

factors by which it may be differentiated from other stands.

Fracture. A break in rock units caused by structural stresses.

Fractures may occur as faults, joints, and planes of fracture

cleavage.

Fragipan. A loamy, brittle subsurface horizon low in porosity

and content of organic matter and low or moderate in clay

but high in silt or very fine sand. A fragipan appears

cemented and restricts roots. When dry, it is hard or very

hard and has a higher bulk density than the horizon or

horizons above. When moist, it tends to rupture suddenly

under pressure rather than to deform slowly.

Freshwater. Water that contains less than 1,000 parts per

million (milligrams per liter) total dissolved solids. This is

the national standard for drinking water.
634 Major Land Resource Areas

Geologic time scales. These are eras, periods, and epochs. The

eras are as follows:

Cenozoic ..................... present to 65 million years BP

Mesozoic .................... 65 to 230 million years BP

Paleozoic .................... 230 to 570 million years BP

Precambrian ............... 570 million to 4.5 billion years BP

The periods are as follows:

Quaternary ................. present to 2 million years BP

Tertiary ....................... 2 to 65 million years BP

Cretaceous .................. 65 to 140 million years BP

Jurassic ........................ 140 to 190 million years BP

Triassic ........................ 190 to 230 million years BP

Permian ....................... 230 to 280 million years BP

Pennsylvanian ............ 280 to 310 million years BP

Mississippian .............. 310 to 345 million years BP

Devonian .................... 345 to 405 million years BP

Silurian ....................... 405 to 425 million years BP

Ordovician ................. 425 to 500 million years BP

Cambrian .................... 500 to 570 million years BP

The epochs are as follows:

Recent (Holocene) ..... present to 10,000 years BP

Pleistocene .................. 10,000 to 2 million years BP

Pliocene ...................... 2 to 10 million years BP

Miocene ...................... 10 to 25 million years BP

Oligocene ................... 25 to 40 million years BP

Eocene ........................ 40 to 55 million years BP

Paleocene .................... 55 to 65 million years BP

Glaciofluvial deposits. Material moved by glaciers and

subsequently sorted and deposited by streams flowing from

the melting ice. The deposits are stratified and occur in the

form of outwash plains, valley trains, deltas, kames, eskers,

and kame terraces.

Glaciolacustrine deposits. Material ranging from fine clay to

sand derived from glaciers and deposited in glacial lakes

mainly by glacial meltwater. Many deposits are bedded or

laminated.

Grassed waterway. A natural or constructed waterway,

typically broad and shallow, seeded to grass as protection

against erosion. Conducts surface water away from

cropland.

Gravel. Rounded or angular fragments of rock as much as 3

inches (2 millimeters to 7.6 centimeters) in diameter. An

individual piece is a pebble.

Green manure crop (agronomy). A soil-improving crop grown

to be plowed under in an early stage of maturity or soon

after maturity.

Ground water. Generally, all subsurface water, as distinguished

from surface water; specifically, that part of the subsurface

water in the saturated zone (a zone in which all voids, large

and small, ideally are filled with water under pressure

greater than atmospheric).

Gully. A small channel with steep sides caused by erosion and

cut in unconsolidated materials by concentrated but

intermittent flow of water. The distinction between a gully

and a rill is one of depth. A gully generally is an obstacle

to farm machinery and is too deep to be obliterated by

ordinary tillage; a rill is of lesser depth and can be

smoothed over by ordinary tillage.

Hardpan. A hardened or cemented soil horizon, or layer. The

soil material is sandy, loamy, or clayey and is cemented by

iron oxide, silica, calcium carbonate, or other substance.

High-residue crops. Such crops as small grain and corn used

for grain. If properly managed, residue from these crops can

be used to control erosion until the next crop in the

rotation is established. These crops return large amounts of

organic matter to the soil.

Hill. A generic term for an elevated area of the land surface,

rising as much as 1,000 feet (305 meters) above

surrounding lowlands, commonly of limited summit area

and having a well defined outline. Slopes are generally

more than 15 percent. The distinction between a hill and a

mountain is arbitrary and may depend on local usage.

Hillslope. A generic term for the steeper part of a hill between

its summit and the drainage line, valley flat, or depression

floor at the base of a hill.

Hydrologic Unit Area. A natural drainage basin or hydrologic

area that includes either the drainage area of a major river

or the combined drainage areas of a series of rivers.

Igneous rock. Rock that was formed by cooling and

solidification of magma and that has not been changed

appreciably by weathering since its formation. Major

varieties include plutonic and volcanic rock (e.g., andesite,

basalt, and granite).

Industrial water use. Use of water for fabrication, processing,

washing, and cooling in industries involved with chemical

and allied products, food, mining, paper and allied

products, petroleum refining, and steel.

Interfluve. A landform composed of the relatively undissected

upland or ridge between two adjacent valleys containing

streams flowing in the same general direction. An elevated

area between two drainageways that sheds water to those

drainageways.

Irrigation. Application of water to soils to assist in the

production of crops and pasture or to maintain plant

growth in recreational areas, such as parks and golf courses.

Kame. A low mound, knob, hummock, or short irregular ridge

composed of stratified sand and gravel deposited by a

subglacial stream as a fan or delta at the margin of a

melting glacier; by a supraglacial stream in a low place or

hole on the surface of the glacier; or as a ponded deposit

on the surface or at the margin of stagnant ice.

Karst (topography). A kind of topography that formed in

limestone, gypsum, or other soluble rocks by dissolution

and that is characterized by closed depressions, sinkholes,

caves, and underground drainage.

Lacustrine deposit. Material deposited in lake water and

exposed when the water level is lowered or the elevation of

the land is raised.
of the United States 635

Lake plain. A nearly level surface marking the floor of an

extinct lake filled by well sorted, generally fine textured,

stratified deposits, commonly containing varves.

Lake terrace. A narrow shelf, partly cut and partly built,

produced along a lakeshore in front of a scarp line of low

cliffs and later exposed when the water level falls.

Landslide. A general, encompassing term for most types of

mass movement landforms and processes involving the

downslope transport and outward deposition of soil and

rock materials caused by gravitational forces; the

movement may or may not involve saturated materials. The

speed and distance of movement, as well as the amount of

soil and rock material, vary greatly.

Livestock water use. Use of water for livestock watering,

feedlots, dairy operations, and other on-farm needs. The

types of livestock include dairy cows and heifers, beef

cattle and calves, sheep and lambs, goats, hogs and pigs,

horses, and poultry.

Loam. Soil material that is 7 to 27 percent clay particles, 28 to

50 percent silt particles, and less than 52 percent sand

particles.

Loess. Material transported and deposited by wind and

consisting dominantly of silt-sized particles.

Mass movement. A generic term for the dislodgment and

downslope transport of soil and rock material as a unit

under direct gravitational stress.

Meander belt. The zone within which migration of a

meandering channel occurs; the flood-plain area included

between two imaginary lines drawn tangential to the outer

bends of active channel loops.

Meander scar. A crescent-shaped, concave or linear mark on

the face of a bluff or valley wall, produced by the lateral

erosion of a meandering stream that impinged upon and

undercut the bluff.

Medium textured soil. Very fine sandy loam, loam, silt loam, or

silt.

Mesa. A broad, nearly flat topped and commonly isolated

landmass bounded by steep slopes or precipitous cliffs and

capped by layers of resistant, nearly horizontal rocky

material. The summit width is characteristically greater

than the height of the bounding escarpments.

Metamorphic rock. Rock of any origin altered in

mineralogical composition, chemical composition, or

structure by heat, pressure, and movement at depth in the

earth’s crust. Nearly all such rocks are crystalline.

Mine spoil. An accumulation of displaced earthy material, rock,

or other waste material removed during mining or

excavation. Also called earthy fill.

Mineral soil. Soil that is mainly mineral material and low in

organic material. Its bulk density is more than that of

organic soil.

Minimum tillage. Only the tillage essential to crop production

and prevention of soil damage.

Mining water use. Use of water for the extraction of naturally

occurring minerals, including solids, such as coal, sand,

gravel, and ore; liquids, such as crude petroleum; and

gases, such as natural gas. Also includes uses associated

with quarrying, milling, and other preparations customarily

done at the mine site or as part of a mining activity. Does

not include water associated with dewatering of an aquifer

that is not put to beneficial use or with processing, such as

smelting, refining petroleum, or slurry pipeline operations.

These processing uses are considered industrial water uses.

Miscellaneous area. A kind of map unit that has little or no

natural soil and supports little or no vegetation.

Moderately coarse textured soil. Coarse sandy loam, sandy

loam, or fine sandy loam.

Moderately fine textured soil. Clay loam, sandy clay loam, or

silty clay loam.

Moraine. In terms of glacial geology, a mound, ridge, or other

topographically distinct accumulation of unsorted,

unstratified drift, predominantly till, deposited primarily

by the direct action of glacial ice in a variety of landforms.

Also, a general term for a landform composed mainly of till

(except for kame moraines, which are composed mainly of

stratified outwash) that has been deposited by a glacier.

Some types of moraines are disintegration, end, ground,

kame, lateral, recessional, and terminal.

Mountain. A generic term for an elevated area of the land

surface, rising more than 1,000 feet (305 meters) above

surrounding lowlands, commonly of restricted summit area

(relative to a plateau) and generally having steep sides. A

mountain can occur as a single, isolated mass or in a group

forming a chain or range. Mountains are formed primarily

by tectonic activity and/or volcanic action but can also be

formed by differential erosion.

Mudstone. A blocky or massive, fine grained sedimentary rock

in which the proportions of clay and silt are approximately

equal. Also, a general term for such material as clay, silt,

claystone, siltstone, shale, and argillite and that should be

used only when the amounts of clay and silt are not known

or cannot be precisely identified.

Organic matter. Plant and animal residue in the soil in various

stages of decomposition.

Outwash. Stratified and sorted sediments (chiefly sand and

gravel) removed or “washed out” from a glacier by

meltwater streams and deposited in front of or beyond the

end moraine or the margin of a glacier. The coarser material

is deposited nearer to the ice.

Outwash plain. An extensive lowland area of coarse textured

glaciofluvial material. An outwash plain is commonly

smooth; where pitted, it generally is low in relief.

Paleoterrace. An erosional remnant of a terrace that retains the

surface form and alluvial deposits of its origin but was not

emplaced by, and commonly does not grade to, a presentday stream or drainage network.
636 Major Land Resource Areas

Parent material. The unconsolidated organic and mineral

material in which soil forms.

Peat. Unconsolidated material, largely undecomposed organic

matter, that has accumulated under excess moisture.

Pedisediment. A layer of sediment, eroded from the shoulder

and backslope of an erosional slope, that lies on and is

being (or was) transported across a gently sloping erosional

surface at the foot of a receding hill or mountain slope.

Permafrost. Ground, soil, or rock that remains at or below 32

degrees F (0 degrees C) for at least 2 years. It is defined on

the basis of temperature and is not necessarily frozen.

Plateau (geomorphology). A comparatively flat area of great

extent and elevation; specifically, an extensive land region

that is considerably elevated (more than 330 feet, or 100

meters) above the adjacent lower lying terrain, is

commonly limited on at least one side by an abrupt

descent, and has a flat or nearly level surface. A

comparatively large part of a plateau surface is near summit

level.

Playa. The generally dry and nearly level lake plain that

occupies the lowest parts of closed depressions, such as

those on intermontane basin floors. Temporary flooding

occurs primarily in response to precipitation and runoff.

Playa deposits are fine grained and may or may not have a

high water table and saline conditions.

Ponding. Standing water on soils in closed depressions. Unless

the soils are artificially drained, the water can be removed

only by percolation or evapotranspiration.

Productivity, soil. The capability of a soil for producing a

specified plant or sequence of plants under specific

management.

Profile, soil. A vertical section of the soil extending through all

its horizons and into the parent material.

Proper grazing use. Grazing at an intensity that maintains

enough cover to protect the soil and maintain or improve

the quantity and quality of the desirable vegetation. This

practice increases the vigor and reproduction capacity of

the key plants and promotes the accumulation of litter and

mulch necessary to conserve soil and water.

Public water use. Use of water provided by a public supplier

for such purposes as firefighting, street washing, flushing

of water lines, and maintaining municipal parks and

swimming pools. Generally, public-use water is not billed

by the public supplier.

Public-supply water. Water withdrawn by public and private

water suppliers that furnish water to at least 25 people or

have a minimum of 15 connections. Public suppliers

provide water for a variety of uses, such as domestic,

commercial, industrial, thermoelectric power, and public

water uses.

Rangeland. Land on which the potential natural vegetation is

predominantly grasses, grasslike plants, forbs, or shrubs

suitable for grazing or browsing. It includes natural

grasslands, savannas, many wetlands, some deserts,

tundras, and areas that support certain forb and shrub

communities.

Red beds. Sedimentary strata that are mainly red and are made

up largely of sandstone and shale.

Relief. The relative difference in elevation between the upland

summits and the lowlands or valleys of a given region.

Residuum (residual soil material). Unconsolidated, weathered

or partly weathered mineral material that accumulated as

bedrock disintegrated in place.

Return flow. Water that reaches a ground or surface water

source after release from the point of use, when it is

available for further use.

Rill. A very small, steep-sided channel resulting from erosion

and cut in unconsolidated materials by concentrated but

intermittent flow of water. A rill generally is not an obstacle

to wheeled vehicles and is shallow enough to be smoothed

over by ordinary tillage.

Rock fragments. Rock or mineral fragments having a diameter

of 2 millimeters or more; for example, pebbles, cobbles,

stones, and boulders.

Root zone. The part of the soil that can be penetrated by plant

roots.

Runoff. The precipitation discharged into stream channels from

an area. The water that flows off the surface of the land

without sinking into the soil is called surface runoff. Water

that enters the soil before reaching surface streams is called

ground-water runoff or seepage flow from ground water.

Rural water use. Use of water in suburban or farm areas for

domestic and livestock needs. The water generally is selfsupplied and includes domestic water, drinking water for

livestock, and water used for other purposes, such as dairy

sanitation, cleaning, and waste disposal.

Saline soil. A soil containing soluble salts in an amount that

impairs growth of plants. A saline soil does not contain

excess exchangeable sodium.

Saline water. Water that contains 1,000 parts per million

(milligrams per liter) or more total dissolved solids. All

water reported as used for public supply, livestock

watering, and irrigation is considered to be freshwater even

though the level of total dissolved solids may exceed

1,000 parts per million (milligrams per liter).

Sand. As a soil separate, individual rock or mineral fragments

from 0.05 millimeter to 2.0 millimeters in diameter. Most

sand grains consist of quartz. As a soil textural class, a soil

that is 85 percent or more sand and not more than 10

percent clay.

Sandstone. Sedimentary rock containing dominantly sandsized particles.

Sedimentary rock. A consolidated deposit of clastic particles,

chemical precipitates, or organic remains accumulated at or

near the surface of the earth under normal low temperature

and pressure conditions. Sedimentary rocks include
of the United States 637

consolidated equivalents of alluvium, colluvium, drift, and

eolian, lacustrine, and marine deposits. Examples are

sandstone, siltstone, mudstone, claystone, shale,

conglomerate, limestone, dolomite, and coal.

Series, soil. A group of soils that have profiles that are almost

alike, except for differences in texture of the surface layer.

All the soils of a series have horizons that are similar in

composition, thickness, and arrangement.

Shale. Sedimentary rock that formed by the hardening of a

deposit of clay, silty clay, or silty clay loam and that has a

tendency to split into thin layers.

Sheet erosion. The removal of a fairly uniform layer of soil

material from the land surface by the action of rainfall and

surface runoff.

Shoulder. The convex, erosional surface near the top of a

hillslope. A shoulder is a transition from summit to

backslope.

Side slope (geomorphology). A geomorphic component of hills

consisting of a laterally planar area of a hillside. The

overland waterflow is predominantly parallel. Side slopes

are dominantly colluvium and slope-wash sediments.

Silica. A combination of silicon and oxygen. The mineral form

is called quartz.

Silt. As a soil separate, individual mineral particles that range in

diameter from the upper limit of clay (0.002 millimeter) to

the lower limit of very fine sand (0.05 millimeter). As a soil

textural class, soil that is 80 percent or more silt and less

than 12 percent clay.

Siltstone. An indurated silt having the texture and composition

of shale but lacking its fine lamination or fissility; a

massive mudstone in which silt predominates over clay.

Sinkhole. A closed, circular or elliptical depression, commonly

funnel shaped, characterized by subsurface drainage and

formed either by dissolution of the surface of underlying

bedrock (e.g., limestone, gypsum, or salt) or by collapse of

underlying caves within bedrock. Complexes of sinkholes

in carbonate-rock terrain are the main components of karst

topography.

Slope alluvium. Sediment gradually transported down the

slopes of mountains or hills primarily by nonchannel

alluvial processes (i.e., slope-wash processes) and

characterized by particle sorting. Lateral particle sorting is

evident on long slopes. In a profile sequence, sediments

may be distinguished by differences in size and/or specific

gravity of rock fragments and may be separated by stone

lines. Burnished peds and sorting of rounded or

subrounded pebbles or cobbles distinguish these materials

from unsorted colluvial deposits.

Soil. A natural, three-dimensional body at the earth’s surface. It

is capable of supporting plants and has properties resulting

from the integrated effect of climate and living matter

acting on earthy parent material, as conditioned by relief

and by the passage of time.

Solum. The upper part of a soil profile, above the C horizon, in

which the processes of soil formation are active. The solum

in soil consists of the A, E, and B horizons. Generally, the

characteristics of the material in these horizons are unlike

those of the material below the solum. The living roots and

plant and animal activities are largely confined to the

solum.

Stones. Rock fragments 10 to 24 inches (25 to 60 centimeters)

in diameter if rounded or 15 to 24 inches (38 to 60

centimeters) in length if flat.

Stony. Refers to a soil containing stones in numbers that

interfere with or prevent tillage.

Stream terrace. One of a series of platforms in a stream valley,

flanking and more or less parallel to the stream channel,

originally formed near the level of the stream; represents

the remnants of an abandoned flood plain, stream bed, or

valley floor produced during a former state of fluvial

erosion or deposition.

Stripcropping. Growing crops in a systematic arrangement of

strips or bands that provide vegetative barriers to wind

erosion and water erosion.

Subsoil. Technically, the B horizon; roughly, the part of the

solum below plow depth.

Subsoiling. Tilling a soil below normal plow depth, ordinarily

to shatter a hardpan or claypan.

Substratum. The part of the soil below the solum.

Summer fallow. The tillage of uncropped land during the

summer to control weeds and allow storage of moisture in

the soil for the growth of a later crop. A practice common in

semiarid regions, where annual precipitation is not enough

to produce a crop every year. Summer fallow is frequently

practiced before planting winter grain.

Summit. The topographically highest position of a hillslope. It

has a nearly level (planar or only slightly convex) surface.

Surface layer. The soil ordinarily moved in tillage, or its

equivalent in uncultivated soil, ranging in depth from 4 to

10 inches (10 to 25 centimeters). Frequently designated as

the “plow layer.”

Surface water. An open body of water, such as a stream or lake.

Talus. Rock fragments of any size or shape (commonly coarse

and angular) derived from and lying at the base of a cliff or

very steep rock slope. The accumulated mass of such loose

broken rock formed chiefly by falling, rolling, or sliding.

Terminal moraine. An end moraine that marks the farthest

advance of a glacier. It typically has the form of a massive

arcuate or concentric ridge, or complex of ridges, and is

underlain by till and other types of drift.

Terrace (conservation). An embankment, or ridge, constructed

across sloping soils on the contour or at a slight angle to
638

the contour. The terrace intercepts surface runoff so that

water soaks into the soil or flows slowly to a prepared

outlet. A terrace in a field generally is built so that the field

can be farmed. A terrace intended mainly for drainage has a

deep channel that is maintained in permanent sod.

Terrace (geomorphology). A steplike surface, bordering a

valley floor or shoreline, that represents the former position

of a flood plain, lake, or seashore. The term is usually

applied both to the relatively flat summit surface (tread)

that was cut or built by stream or wave action and to the

steeper descending slope (scarp or riser) that has graded to

a lower base level of erosion.

Texture, soil. The relative proportions of sand, silt, and clay

particles in a mass of soil. The basic textural classes, in

order of increasing proportion of fine particles, are sand,

loamy sand, sandy loam, loam, silt loam, silt, sandy clay

loam, clay loam, silty clay loam, sandy clay, silty clay, and

clay. The sand, loamy sand, and sandy loam classes may be

further divided by specifying “coarse,” “fine,” or “very

fine.”

Thermoelectric power water use. Use of water in the process

of generating electricity with steam-driven turbine

generators. The term describes the combined public-supply

deliveries to thermoelectric power plants and self-supplied

thermoelectric power withdrawals.

Till. Dominantly unsorted and nonstratified drift, generally

unconsolidated and deposited directly by a glacier without

subsequent reworking by meltwater, and consisting of a

heterogeneous mixture of clay, silt, sand, gravel, stones,

and boulders; rock fragments of various lithologies are

embedded within a finer matrix that can range from clay to

sandy loam.

Till plain. An extensive area of level to gently undulating soils

underlain predominantly by till and bounded at the distal

end by subordinate recessional or end moraines.

Tilth, soil. The physical condition of the soil as related to

tillage, seedbed preparation, seedling emergence, and root

penetration.

Toeslope. The gently inclined surface at the base of a hillslope.

Toeslopes in profile are commonly gentle and linear and

are constructional surfaces forming the lower part of a

hillslope continuum that grades to valley or closeddepression floors.

Topsoil. The upper part of the soil, which is the most favorable

material for plant growth. It is ordinarily rich in organic

matter and is used to topdress roadbanks, lawns, and land

affected by mining.

Total dissolved solids. The total amount of dissolved

constituents (minerals and organic matter) in water.

Tuff. A generic term for any consolidated or cemented deposit

that is 50 percent or more volcanic ash.

Upland. An informal, general term for the higher ground of a

region, in contrast with a low-lying adjacent area, such as a

valley or plain, or for land at a higher elevation than the

flood plain or low stream terrace; land above the footslope

zone of the hillslope continuum.

Valley fill. The unconsolidated sediment deposited by any

agent (water, wind, ice, or mass wasting) so as to fill or

partly fill a valley.

Water bars. Smooth, shallow ditches or depressional areas that

are excavated at an angle across a sloping road. They are

used to reduce the downward velocity of water and divert it

off and away from the road surface. Water bars can easily be

driven over if constructed properly.

Water use. (1) In a restrictive sense, this term refers to the

withdrawal of water for a specific purpose, such as public

supply, domestic use, irrigation, cooling of thermoelectric

power plants, and industrial processing. (2) More broadly,

the term pertains to the interaction of humans with and

their influence on the hydrologic cycle and includes such

elements as water withdrawal, delivery, consumptive use,

wastewater release, reclaimed wastewater, return flow, and

in-stream use.

Water withdrawal. Removal of water from the ground or

diversion of surface water for a specific use.
639

Appendices

Appendix I.—MLRAs, EPA Level III Ecoregions, and Forest Service Ecological Sections

Appendix I cross-references MLRAs with Environmental Protection Agency Level III Ecoregions and

with United States Forest Service ecological units for the conterminous United States. The MLRAs are

listed in numerical order, without regard to the LRRs in which they occur. The percentage column in the

table indicates the extent to which the three resource units overlap. Minor overlaps (those making up

less than 5 percent of the MLRA) are not included in the table.
MLRA Forest Service Section EPA Level III Ecoregion 1 Northern Pacific Coast Range, Foothills, and Valleys M242A Oregon and Washington Coast Ranges 1 Coast Range 2 Willamette and Puget Sound Valleys 242A Puget Trough 2 Puget Lowland 2 Willamette and Puget Sound Valleys 242B Willamette Valley 3 Willamette Valley 

3 Olympic and Cascade Mountains M242B Western Cascades 4 Cascades 

3 Olympic and Cascade Mountains M242D Northern Cascades 77 North Cascades 4A Sitka Spruce Belt M242A Oregon and Washington Coast Ranges 1 Coast Range 4B Coastal Redwood Belt 263A Northern California Coast 1 Coast Range 

4B Coastal Redwood Belt 261A Central California Coast 1 Coast Range 

4B Coastal Redwood Belt 263A Northern California Coast 78 Klamath Mountains 

5 Siskiyou-Trinity Area M261A Klamath Mountains 78 Klamath Mountains 5 Siskiyou-Trinity Area M261B Northern California Coast Ranges 78 Klamath Mountains 

5 Siskiyou-Trinity Area M242B Western Cascades 4 Cascades 

6 Cascade Mountains, Eastern Slope M242C Eastern Cascades 9 Eastern Cascades Slopes and Foothills 

6 Cascade Mountains, Eastern Slope M242D Northern Cascades 77 North Cascades 7 Columbia Basin 342I Columbia Basin 10 Columbia Plateau 

8 Columbia Plateau 342I Columbia Basin 10 Columbia Plateau 

9 Palouse and Nez Perce Prairies 331A Palouse Prairie 10 Columbia Plateau 

9 Palouse and Nez Perce Prairies M332G Blue Mountains 11 Blue Mountains 9 Palouse and Nez Perce Prairies 342I Columbia Basin 10 Columbia Plateau 

10 Central Rocky and Blue Mountain Foothills 342H Blue Mountain Foothills 11 Blue Mountains 

10 Central Rocky and Blue Mountain Foothills 342H Blue Mountain Foothills 80 Northern Basin and Range 

10 Central Rocky and Blue Mountain Foothills 342D Snake River Basalts and Basins 12 Snake River Plain 

11 Snake River Plains 342D Snake River Basalts and Basins 12 Snake River Plain 

12 Lost River Valleys and Mountains 332E Beaverhead Mountains 17 Middle Rockies 

12 Lost River Valleys and Mountains M332F Challis Volcanics 17 Middle Rockies 

13 Eastern Idaho Plateaus 342D Snake River Basalts and Basins 80 Northern Basin and Range 

13 Eastern Idaho Plateaus M331D Overthrust Mountains 80 Northern Basin and Range 13 Eastern Idaho Plateaus 342J Eastern Basin and Range 80 Northern Basin and Range 

13 Eastern Idaho Plateaus 342D Snake River Basalts and Basins 12 Snake River Plain 

14 Central California Coastal Valleys 261A Central California Coast 6 Southern and Central California Chaparral and 

14 Central California Coastal Valleys 263A Northern California Coast 6 Southern and Central California Chaparral and 

14 Central California Coastal Valleys M262A Central California Coast Ranges 6 Southern and Central California Chaparral and 

14 Central California Coastal Valleys M261B Northern California Coast Ranges 6 Southern and Central California Chaparral and 

15 Central California Coast Range M262A Central California Coast Ranges 6 Southern and Central California Chaparral and 

15 Central California Coast Range 261A Central California Coast 6 Southern and Central California Chaparral and 

15 Central California Coast Range M261B Northern California Coast Ranges 6 Southern and Central California Chaparral and 

15 Central California Coast Range M261C Northern California Interior Coast Ranges 6 Southern and Central California Chaparral and 

16 California Delta 262A Great Valley 7 Central California Valley 

16 California Delta 262A Great Valley 6 Southern and Central California Chaparral and 
MLRA Forest Service Section EPA Level III Ecoregion 17 Sacramento and San Joaquin Valleys 262A Great Valley 7 Central California Valley 

17 Sacramento and San Joaquin Valleys 262A Great Valley 6 Southern and Central California Chaparral and 

17 Sacramento and San Joaquin Valleys M261C Northern California Interior Coast Ranges 6 Southern and Central California Chaparral and 

18 Sierra Nevada Foothills M261F Sierra Nevada Foothills 6 Southern and Central California Chaparral and 

18 Sierra Nevada Foothills M261E Sierra Nevada 8 Southern California Mountains 18 Sierra Nevada Foothills 262A Great Valley 7 Central California Valley 

19 Southern California Coastal Plain 261B Southern California Coast 6 Southern and Central California Chaparral and 19 Southern California Coastal Plain M262B Southern California Mountain and Valley 6 Southern and Central California Chaparral and 

20 Southern California Mountains M262B Southern California Mountain and Valley 8 Southern California Mountains 

20 Southern California Mountains M262B Southern California Mountain and Valley 6 Southern and Central California Chaparral and 

20 Southern California Mountains 261B Southern California Coast 6 Southern and Central California Chaparral and 21 Klamath and Shasta Valleys and Basins M261G Modoc Plateau 9 Eastern Cascades Slopes and Foothills 21 Klamath and Shasta Valleys and Basins M261D Southern Cascades 9 Eastern Cascades Slopes and Foothills 21 Klamath and Shasta Valleys and Basins M261G Modoc Plateau 80 Northern Basin and Range 22A Sierra Nevada Mountains M261E Sierra Nevada 5 Sierra Nevada 22B Southern Cascade Mountains M261D Southern Cascades 5 Sierra Nevada 

22B Southern Cascade Mountains M261D Southern Cascades 9 Eastern Cascades Slopes and Foothills 22B Southern Cascade Mountains M261D Southern Cascades 4 Cascades 23 Malheur High Plateau 342B Northwestern Basin and Range 80 Northern Basin and Range 

24 Humboldt Area 341E Northern Mono 13 Central Basin and Range 

24 Humboldt Area M341D West Great Basin and Mountains 13 Central Basin and Range 24 Humboldt Area 342B Northwestern Basin and Range 80 Northern Basin and Range 

24 Humboldt Area 341G Northeastern Great Basin 13 Central Basin and Range 

25 Owyhee High Plateau 342C Owyhee Uplands 80 Northern Basin and Range 

25 Owyhee High Plateau 341G Northeastern Great Basin 80 Northern Basin and Range 

25 Owyhee High Plateau 341G Northeastern Great Basin 13 Central Basin and Range 

25 Owyhee High Plateau 342J Eastern Basin and Range 80 Northern Basin and Range 

25 Owyhee High Plateau M341A East Great Basin and Mountains 13 Central Basin and Range 26 Carson Basin and Mountains 341D Mono 13 Central Basin and Range 

26 Carson Basin and Mountains 342B Northwestern Basin and Range 13 Central Basin and Range 

26 Carson Basin and Mountains 341E Northern Mono 13 Central Basin and Range 

27 Fallon-Lovelock Area 341E Northern Mono 13 Central Basin and Range 

27 Fallon-Lovelock Area 342B Northwestern Basin and Range 13 Central Basin and Range 

27 Fallon-Lovelock Area M341D West Great Basin and Mountains 13 Central Basin and Range 28A Great Salt Lake Area 341A Bonneville Basin 13 Central Basin and Range 

28A Great Salt Lake Area M341A East Great Basin and Mountains 13 Central Basin and Range 28A Great Salt Lake Area 342J Eastern Basin and Range 13 Central Basin and Range 

28B Central Nevada Basin and Range M341A East Great Basin and Mountains 13 Central Basin and Range 28B Central Nevada Basin and Range M341D West Great Basin and Mountains 13 Central Basin and Range 28B Central Nevada Basin and Range 341F Southeastern Great Basin 13 Central Basin and Range 
MLRA Forest Service Section EPA Level III Ecoregion 29 Southern Nevada Basin and Range 341F Southeastern Great Basin 13 Central Basin and Range 

29 Southern Nevada Basin and Range 341F Southeastern Great Basin 14 Mojave Basin and Range 

29 Southern Nevada Basin and Range 341D Mono 13 Central Basin and Range 

30 Mojave Desert 322A Mojave Desert 14 Mojave Basin and Range 

31 Lower Colorado Desert 322C Colorado Desert 81 Sonoran Basin and Range 

31 Lower Colorado Desert 322B Sonoran Desert 81 Sonoran Basin and Range 

31 Lower Colorado Desert 322A Mojave Desert 81 Sonoran Basin and Range 

31 Lower Colorado Desert M262B Southern California Mountain and Valley 81 Sonoran Basin and Range 

32 Northern Intermountain Desertic Basins 342A Bighorn Basin 18 Wyoming Basin 32 Northern Intermountain Desertic Basins 342F Central Basin and Hills 18 Wyoming Basin 

34A Cool Central Desertic Basins and Plateaus 342G Green River Basin 18 Wyoming Basin 

34A Cool Central Desertic Basins and Plateaus 342F Central Basin and Hills 18 Wyoming Basin 

34B Warm Central Desertic Basins and Plateaus 341B Northern Canyonlands 20 Colorado Plateaus 

34B Warm Central Desertic Basins and Plateaus 341C Uinta Basin 20 Colorado Plateaus 

34B Warm Central Desertic Basins and Plateaus M341B Tavaputs Plateau 20 Colorado Plateaus 34B Warm Central Desertic Basins and Plateaus M331H North-Central Highlands and Rocky Mountains 20 Colorado Plateaus 

35 Colorado Plateau 313B Navaho Canyonlands 22 Arizona/New Mexico Plateau 

35 Colorado Plateau 313A Grand Canyon 22 Arizona/New Mexico Plateau 

35 Colorado Plateau 313D Painted Desert 22 Arizona/New Mexico Plateau 

35 Colorado Plateau 313A Grand Canyon 20 Colorado Plateaus 

35 Colorado Plateau 341B Northern Canyonlands 20 Colorado Plateaus 

35 Colorado Plateau 313B Navaho Canyonlands 23 Arizona/New Mexico Mountains 

36 Southwestern Plateaus, Mesas, and Foothills 341B Northern Canyonlands 20 Colorado Plateaus 

36 Southwestern Plateaus, Mesas, and Foothills 313A Grand Canyon 20 Colorado Plateaus 

36 Southwestern Plateaus, Mesas, and Foothills 313B Navaho Canyonlands 21 Southern Rockies 

36 Southwestern Plateaus, Mesas, and Foothills 313B Navaho Canyonlands 22 Arizona/New Mexico Plateau 

36 Southwestern Plateaus, Mesas, and Foothills M331G South-Central Highlands 21 Southern Rockies 38 Mogollon Transition 313C Tonto Transition 23 Arizona/New Mexico Mountains 

38 Mogollon Transition M313A White Mountains-San Francisco Peaks-Mogollon 23 Arizona/New Mexico Mountains 

Rim 38 Mogollon Transition 313C Tonto Transition 79 Madrean Archipelago 

39 Arizona and New Mexico Mountains M313A White Mountains-San Francisco Peaks-Mogollon 23 Arizona/New Mexico Mountains 

Rim 39 Arizona and New Mexico Mountains M313B Sacramento-Monzano Mountains 23 Arizona/New Mexico Mountains 

40 Sonoran Basin and Range 322B Sonoran Desert 81 Sonoran Basin and Range 

41 Southeastern Arizona Basin and Range 321A Basin and Range 79 Madrean Archipelago 

41 Southeastern Arizona Basin and Range 321A Basin and Range 24 Chihuahuan Deserts 

42 Southern Desertic Basins, Plains, and Mountains 321A Basin and Range 24 Chihuahuan Deserts 

42 Southern Desertic Basins, Plains, and Mountains 315A Pecos Valley 24 Chihuahuan Deserts 

43A Northern Rocky Mountains M333A Okanogan Highland 15 Northern Rockies 43A Northern Rocky Mountains M333D Bitterroot Mountains 15 Northern Rockies 43A Northern Rocky Mountains M333B Flathead Valley 15 Northern Rockies 

43A Northern Rocky Mountains M333C Northern Rockies 41 Canadian Rockies 
MLRA Forest Service Section EPA Level III Ecoregion 43B Central Rocky Mountains M332A Idaho Batholith 16 Idaho Batholith 43B Central Rocky Mountains M331A Yellowstone Highlands 17 Middle Rockies 43B Central Rocky Mountains M331D Overthrust Mountains 17 Middle Rockies 43B Central Rocky Mountains M332D Belt Mountains 17 Middle Rockies 43B Central Rocky Mountains M332E Beaverhead Mountains 17 Middle Rockies 43B Central Rocky Mountains M332B Northern Rockies and Bitterroot Valley 17 Middle Rockies 

43B Central Rocky Mountains M332F Challis Volcanics 16 Idaho Batholith 43C Blue and Seven Devils Mountains M332G Blue Mountains 11 Blue Mountains 44 Northern Rocky Mountain Valleys M332E Beaverhead Mountains 17 Middle Rockies 44 Northern Rocky Mountain Valleys M333A Okanogan Highland 15 Northern Rockies 44 Northern Rocky Mountain Valleys M332D Belt Mountains 17 Middle Rockies 

44 Northern Rocky Mountain Valleys M332B Northern Rockies and Bitterroot Valley 17 Middle Rockies 

44 Northern Rocky Mountain Valleys M333B Flathead Valley 15 Northern Rockies 

44 Northern Rocky Mountain Valleys M332D Belt Mountains 43 Northwestern Great Plains 

46 Northern Rocky Mountain Foothills 331D Northwestern Glaciated Plains 42 Northwestern Glaciated Plains 46 Northern Rocky Mountain Foothills 331N Belt Mountains 43 Northwestern Great Plains 

46 Northern Rocky Mountain Foothills 331K North Central Highlands 43 Northwestern Great Plains 

46 Northern Rocky Mountain Foothills M332D Belt Mountains 43 Northwestern Great Plains 46 Northern Rocky Mountain Foothills 331K North Central Highlands 42 Northwestern Glaciated Plains 47 Wasatch and Uinta Mountains M341C Utah High Plateau 19 Wasatch and Uinta Mountains 

47 Wasatch and Uinta Mountains M331D Overthrust Mountains 19 Wasatch and Uinta Mountains 

47 Wasatch and Uinta Mountains M331E Uinta Mountains 19 Wasatch and Uinta Mountains 

47 Wasatch and Uinta Mountains M331E Uinta Mountains 20 Colorado Plateaus 47 Wasatch and Uinta Mountains 342E Bear Lake 18 Wyoming Basin 

48A Southern Rocky Mountains M331I Northern Parks and Ranges 21 Southern Rockies 

48A Southern Rocky Mountains M331G South-Central Highlands 21 Southern Rockies 48A Southern Rocky Mountains M331H North-Central Highlands and Rocky Mountains 21 Southern Rockies 48A Southern Rocky Mountains M331F Southern Parks and Rocky Mountain Range 21 Southern Rockies 

48A Southern Rocky Mountains M341B Tavaputs Plateau 20 Colorado Plateaus 

48B Southern Rocky Mountain Parks M331I Northern Parks and Ranges 21 Southern Rockies 

49 Southern Rocky Mountain Foothills M331I Northern Parks and Ranges 21 Southern Rockies 49 Southern Rocky Mountain Foothills 331I Arkansas Tablelands 26 Southwestern Tablelands 

49 Southern Rocky Mountain Foothills M331F Southern Parks and Rocky Mountain Range 21 Southern Rockies 

49 Southern Rocky Mountain Foothills 331H Central High Plains 25 High Plains 51 High Intermountain Valleys 331J Northern Rio Grande Basin 22 Arizona/New Mexico Plateau 

51 High Intermountain Valleys 331J Northern Rio Grande Basin 21 Southern Rockies 

52 Brown Glaciated Plain 331L Glaciated Northern Grasslands 42 Northwestern Glaciated Plains 

52 Brown Glaciated Plain 331D Northwestern Glaciated Plains 42 Northwestern Glaciated Plains 

53A Northern Dark Brown Glaciated Plains 331E Northeastern Glaciated Plains 42 Northwestern Glaciated Plains 

53A Northern Dark Brown Glaciated Plains 331L Glaciated Northern Grasslands 42 Northwestern Glaciated Plains 

53A Northern Dark Brown Glaciated Plains 332A Northeastern Glaciated Plains 46 Northern Glaciated Plains 
MLRA Forest Service Section EPA Level III Ecoregion 53B Central Dark Brown Glaciated Plains 331E Northeastern Glaciated Plains 42 Northwestern Glaciated Plains 

53B Central Dark Brown Glaciated Plains 332B Western Glaciated Plains 46 Northern Glaciated Plains 

53C Southern Dark Brown Glaciated Plains 332B Western Glaciated Plains 42 Northwestern Glaciated Plains 

53C Southern Dark Brown Glaciated Plains 332D North-Central Great Plains 42 Northwestern Glaciated Plains 

53C Southern Dark Brown Glaciated Plains 331E Northeastern Glaciated Plains 42 Northwestern Glaciated Plains 

54 Rolling Soft Shale Plain 331M Missouri Plateau 43 Northwestern Great Plains 

54 Rolling Soft Shale Plain 331F Western Great Plains 43 Northwestern Great Plains 

55A Northern Black Glaciated Plains 332A Northeastern Glaciated Plains 46 Northern Glaciated Plains 

55B Central Black Glaciated Plains 332A Northeastern Glaciated Plains 46 Northern Glaciated Plains 

55B Central Black Glaciated Plains 332B Western Glaciated Plains 46 Northern Glaciated Plains 

55C Southern Black Glaciated Plains 332B Western Glaciated Plains 46 Northern Glaciated Plains 

55C Southern Black Glaciated Plains 251B North Central Glaciated Plains 46 Northern Glaciated Plains 

55C Southern Black Glaciated Plains 332D North-Central Great Plains 42 Northwestern Glaciated Plains 

56 Red River Valley of the North 251A Red River Valley 48 Lake Agassiz Plain 

56 Red River Valley of the North 222N Lake Agassiz-Aspen Parklands 48 Lake Agassiz Plain 

56 Red River Valley of the North 222N Lake Agassiz-Aspen Parklands 49 Northern Minnesota Wetlands 

57 Northern Minnesota Gray Drift 212N Northern Minnesota Drift and Lake Plains 50 Northern Lakes and Forests 

57 Northern Minnesota Gray Drift 222M Minnesota and Northeast Iowa Morainal-Oak 51 North Central Hardwood Forests 

Savannah 57 Northern Minnesota Gray Drift 212N Northern Minnesota Drift and Lake Plains 51 North Central Hardwood Forests 

57 Northern Minnesota Gray Drift 212L Northern Superior Uplands 50 Northern Lakes and Forests 

58A Northern Rolling High Plains, Northern Part 331K North Central Highlands 43 Northwestern Great Plains 

58A Northern Rolling High Plains, Northern Part 331G Powder River Basin 43 Northwestern Great Plains 

58A Northern Rolling High Plains, Northern Part 331M Missouri Plateau 43 Northwestern Great Plains 

58A Northern Rolling High Plains, Northern Part 331N Belt Mountains 43 Northwestern Great Plains 58B Northern Rolling High Plains, Southern Part 331G Powder River Basin 43 Northwestern Great Plains 

58C Northern Rolling High Plains, Northeastern Part 331M Missouri Plateau 43 Northwestern Great Plains 

58D Northern Rolling High Plains, Eastern Part 331M Missouri Plateau 43 Northwestern Great Plains 

60A Pierre Shale Plains 331F Western Great Plains 43 Northwestern Great Plains 

60B Pierre Shale Plains, Northern Part 331K North Central Highlands 43 Northwestern Great Plains 60B Pierre Shale Plains, Northern Part 331M Missouri Plateau 43 Northwestern Great Plains 

60B Pierre Shale Plains, Northern Part 331F Western Great Plains 43 Northwestern Great Plains 

61 Black Hills Foot Slopes M334A Black Hills 17 Middle Rockies 

62 Black Hills M334A Black Hills 17 Middle Rockies 63A Northern Rolling Pierre Shale Plains 331F Western Great Plains 43 Northwestern Great Plains 

63B Southern Rolling Pierre Shale Plains 331F Western Great Plains 43 Northwestern Great Plains 

63B Southern Rolling Pierre Shale Plains 332D North-Central Great Plains 42 Northwestern Glaciated Plains 
MLRA Forest Service Section EPA Level III Ecoregion 64 Mixed Sandy and Silty Tableland and Badlands 331F Western Great Plains 25 High Plains 

64 Mixed Sandy and Silty Tableland and Badlands 331F Western Great Plains 43 Northwestern Great Plains 

65 Nebraska Sand Hills 332C Nebraska Sand Hills 44 Nebraska Sand Hills 

66 Dakota-Nebraska Eroded Tableland 331F Western Great Plains 43 Northwestern Great Plains 

66 Dakota-Nebraska Eroded Tableland 332D North-Central Great Plains 42 Northwestern Glaciated Plains 

66 Dakota-Nebraska Eroded Tableland 332D North-Central Great Plains 43 Northwestern Great Plains 

66 Dakota-Nebraska Eroded Tableland 332C Nebraska Sand Hills 44 Nebraska Sand Hills 

66 Dakota-Nebraska Eroded Tableland 332C Nebraska Sand Hills 42 Northwestern Glaciated Plains 

66 Dakota-Nebraska Eroded Tableland 332D North-Central Great Plains 44 Nebraska Sand Hills 

67A Central High Plains, Northern Part 331F Western Great Plains 25 High Plains 

67A Central High Plains, Northern Part 331H Central High Plains 25 High Plains 

67B Central High Plains, Southern Part 331H Central High Plains 25 High Plains 

67B Central High Plains, Southern Part 331C Central High Tablelands 25 High Plains 

67B Central High Plains, Southern Part 331I Arkansas Tablelands 26 Southwestern Tablelands 

67B Central High Plains, Southern Part 331B Southern High Plains 25 High Plains 

67B Central High Plains, Southern Part 331I Arkansas Tablelands 25 High Plains 

69 Upper Arkansas Valley Rolling Plains 331I Arkansas Tablelands 26 Southwestern Tablelands 

70A Canadian River Plains and Valleys 331B Southern High Plains 26 Southwestern Tablelands 

70A Canadian River Plains and Valleys 315B Texas High Plains 26 Southwestern Tablelands 

70A Canadian River Plains and Valleys M313B Sacramento-Monzano Mountains 22 Arizona/New Mexico Plateau 

70A Canadian River Plains and Valleys M313B Sacramento-Monzano Mountains 26 Southwestern Tablelands 

70A Canadian River Plains and Valleys 315B Texas High Plains 25 High Plains 

70B Upper Pecos River Valley 315B Texas High Plains 26 Southwestern Tablelands 

70B Upper Pecos River Valley 315A Pecos Valley 26 Southwestern Tablelands 70B Upper Pecos River Valley 315A Pecos Valley 22 Arizona/New Mexico Plateau 70B Upper Pecos River Valley 315A Pecos Valley 24 Chihuahuan Deserts 

70B Upper Pecos River Valley 315B Texas High Plains 25 High Plains 

70C Central New Mexico Highlands 315A Pecos Valley 22 Arizona/New Mexico Plateau 70C Central New Mexico Highlands M313B Sacramento-Monzano Mountains 22 Arizona/New Mexico Plateau 

70C Central New Mexico Highlands M313B Sacramento-Monzano Mountains 23 Arizona/New Mexico Mountains 

70C Central New Mexico Highlands 321A Basin and Range 22 Arizona/New Mexico Plateau 

70D Southern Desert Foothills 315A Pecos Valley 24 Chihuahuan Deserts 

70D Southern Desert Foothills 315A Pecos Valley 23 Arizona/New Mexico Mountains 70D Southern Desert Foothills 321A Basin and Range 24 Chihuahuan Deserts 

70D Southern Desert Foothills M313B Sacramento-Monzano Mountains 23 Arizona/New Mexico Mountains 

71 Central Nebraska Loess Hills 332C Nebraska Sand Hills 27 Central Great Plains 

72 Central High Tableland 331C Central High Tablelands 25 High Plains 

72 Central High Tableland 331H Central High Plains 25 High Plains 

72 Central High Tableland 331B Southern High Plains 25 High Plains 

72 Central High Tableland 331C Central High Tablelands 27 Central Great Plains 

73 Rolling Plains and Breaks 332E South-Central Great Plains 27 Central Great Plains 

73 Rolling Plains and Breaks 332C Nebraska Sand Hills 27 Central Great Plains 
MLRA Forest Service Section EPA Level III Ecoregion 74 Central Kansas Sandstone Hills 332E South-Central Great Plains 27 Central Great Plains 

74 Central Kansas Sandstone Hills 251F Flint Hills 27 Central Great Plains 

74 Central Kansas Sandstone Hills 251F Flint Hills 28 Flint Hills 

75 Central Loess Plains 332E South-Central Great Plains 27 Central Great Plains 

75 Central Loess Plains 251H Nebraska Rolling Hills 27 Central Great Plains 

75 Central Loess Plains 332C Nebraska Sand Hills 27 Central Great Plains 

76 Bluestem Hills 251F Flint Hills 28 Flint Hills 

76 Bluestem Hills 255A Cross Timbers and Prairie 28 Flint Hills 

76 Bluestem Hills 251H Nebraska Rolling Hills 28 Flint Hills 

77A Southern High Plains, Northern Part 331B Southern High Plains 25 High Plains 

77A Southern High Plains, Northern Part 331B Southern High Plains 26 Southwestern Tablelands 

77B Southern High Plains, Northwestern Part 331B Southern High Plains 26 Southwestern Tablelands 

77B Southern High Plains, Northwestern Part 315B Texas High Plains 25 High Plains 

77B Southern High Plains, Northwestern Part 331B Southern High Plains 25 High Plains 

77B Southern High Plains, Northwestern Part 315B Texas High Plains 26 Southwestern Tablelands 

77C Southern High Plains, Southern Part 315B Texas High Plains 25 High Plains 

77D Southern High Plains, Southwestern Part 315B Texas High Plains 25 High Plains 

77E Southern High Plains, Breaks 315F Northern Texas High Plains 26 Southwestern Tablelands 

77E Southern High Plains, Breaks 315F Northern Texas High Plains 25 High Plains 

78A Rolling Limestone Prairie 315C Rolling Plains 27 Central Great Plains 

78A Rolling Limestone Prairie 315G Eastern Rolling Plains 27 Central Great Plains 

78B Central Rolling Red Plains, Western Part 315C Rolling Plains 26 Southwestern Tablelands 

78B Central Rolling Red Plains, Western Part 315C Rolling Plains 27 Central Great Plains 

78B Central Rolling Red Plains, Western Part 315F Northern Texas High Plains 26 Southwestern Tablelands 

78C Central Rolling Red Plains, Eastern Part 332F South Central and Red Bed Plains 27 Central Great Plains 

78C Central Rolling Red Plains, Eastern Part 315C Rolling Plains 27 Central Great Plains 

78C Central Rolling Red Plains, Eastern Part 332F South Central and Red Bed Plains 26 Southwestern Tablelands 

78C Central Rolling Red Plains, Eastern Part 315F Northern Texas High Plains 27 Central Great Plains 

79 Great Bend Sand Plains 332E South-Central Great Plains 27 Central Great Plains 

79 Great Bend Sand Plains 332F South Central and Red Bed Plains 27 Central Great Plains 

80A Central Rolling Red Prairies 255A Cross Timbers and Prairie 27 Central Great Plains 

80A Central Rolling Red Prairies 332F South Central and Red Bed Plains 27 Central Great Plains 

80A Central Rolling Red Prairies 255A Cross Timbers and Prairie 29 Cross Timbers 

80A Central Rolling Red Prairies 315G Eastern Rolling Plains 27 Central Great Plains 

80B Texas North-Central Prairies 315G Eastern Rolling Plains 29 Cross Timbers 

80B Texas North-Central Prairies 315G Eastern Rolling Plains 27 Central Great Plains 

81A Edwards Plateau, Western Part 321B Stockton Plateau 24 Chihuahuan Deserts 

81A Edwards Plateau, Western Part 321B Stockton Plateau 30 Edwards Plateau 

81A Edwards Plateau, Western Part 315C Rolling Plains 30 Edwards Plateau 

81A Edwards Plateau, Western Part 321B Stockton Plateau 25 High Plains 
MLRA Forest Service Section EPA Level III Ecoregion 81B Edwards Plateau, Central Part 315D Edwards Plateau 30 Edwards Plateau 

81B Edwards Plateau, Central Part 315C Rolling Plains 30 Edwards Plateau 

81C Edwards Plateau, Eastern Part 315D Edwards Plateau 30 Edwards Plateau 

81C Edwards Plateau, Eastern Part 315D Edwards Plateau 29 Cross Timbers 

81D Southern Edwards Plateau 321B Stockton Plateau 24 Chihuahuan Deserts 

81D Southern Edwards Plateau 321A Basin and Range 24 Chihuahuan Deserts 

82A Texas Central Basin 315D Edwards Plateau 30 Edwards Plateau 

82B Wichita Mountains 332F South Central and Red Bed Plains 27 Central Great Plains 

82B Wichita Mountains 255A Cross Timbers and Prairie 27 Central Great Plains 83A Northern Rio Grande Plain 315E Rio Grande Plain 31 Southern Texas Plains 

83A Northern Rio Grande Plain 315E Rio Grande Plain 33 East Central Texas Plains 

83B Western Rio Grande Plain 315E Rio Grande Plain 31 Southern Texas Plains 

83C Central Rio Grande Plain 315E Rio Grande Plain 31 Southern Texas Plains 

83C Central Rio Grande Plain 315E Rio Grande Plain 34 Western Gulf Coastal Plain 

83D Lower Rio Grande Plain 315E Rio Grande Plain 34 Western Gulf Coastal Plain 

83D Lower Rio Grande Plain 315E Rio Grande Plain 31 Southern Texas Plains 

83E Sandsheet Prairie 315E Rio Grande Plain 34 Western Gulf Coastal Plain 

83E Sandsheet Prairie 255D Central Gulf Prairie and Marshes 34 Western Gulf Coastal Plain 

84A North Cross Timbers 255A Cross Timbers and Prairie 29 Cross Timbers 

84B West Cross Timbers 255E Texas Cross Timbers and Prairie 29 Cross Timbers 

84B West Cross Timbers 255A Cross Timbers and Prairie 29 Cross Timbers 

84B West Cross Timbers 315G Eastern Rolling Plains 29 Cross Timbers 

84C East Cross Timbers 255E Texas Cross Timbers and Prairie 29 Cross Timbers 

85 Grand Prairie 255E Texas Cross Timbers and Prairie 29 Cross Timbers 

85 Grand Prairie 255A Cross Timbers and Prairie 29 Cross Timbers 

86A Texas Blackland Prairie, Northern Part 255B Blackland Prairie 32 Texas Blackland Prairies 

86A Texas Blackland Prairie, Northern Part 255C Oak Woods and Prairie 33 East Central Texas Plains 

86A Texas Blackland Prairie, Northern Part 255C Oak Woods and Prairie 32 Texas Blackland Prairies 

86B Texas Blackland Prairie, Southern Part 255C Oak Woods and Prairie 32 Texas Blackland Prairies 

86B Texas Blackland Prairie, Southern Part 255C Oak Woods and Prairie 33 East Central Texas Plains 

87A Texas Claypan Area, Southern Part 255C Oak Woods and Prairie 33 East Central Texas Plains 

87A Texas Claypan Area, Southern Part 255C Oak Woods and Prairie 32 Texas Blackland Prairies 

87B Texas Claypan Area, Northern Part 255C Oak Woods and Prairie 33 East Central Texas Plains 

87B Texas Claypan Area, Northern Part 255B Blackland Prairie 33 East Central Texas Plains 

87B Texas Claypan Area, Northern Part 231E Mid Coastal Plains-Western 33 East Central Texas Plains 

87B Texas Claypan Area, Northern Part 231E Mid Coastal Plains-Western 35 South Central Plains 

87B Texas Claypan Area, Northern Part 255A Cross Timbers and Prairie 35 South Central Plains 
MLRA Forest Service Section EPA Level III Ecoregion 88 Northern Minnesota Glacial Lake Basins 212M Northern Minnesota and Ontario 49 Northern Minnesota Wetlands 

88 Northern Minnesota Glacial Lake Basins 212N Northern Minnesota Drift and Lake Plains 50 Northern Lakes and Forests 89 Wisconsin Central Sands 222R Wisconsin Central Sands 51 North Central Hardwood Forests 

90A Wisconsin and Minnesota Thin Loess and Till, Northern 212X Northern Highlands 50 Northern Lakes and Forests 

Part 90A Wisconsin and Minnesota Thin Loess and Till, Northern 212K Western Superior Uplands 50 Northern Lakes and Forests 

Part 90A Wisconsin and Minnesota Thin Loess and Till, Northern 212Q North Central Wisconsin Uplands 51 North Central Hardwood Forests 

Part 90A Wisconsin and Minnesota Thin Loess and Till, Northern 212T Northern Green Bay Lobe 51 North Central Hardwood Forests 

Part 90A Wisconsin and Minnesota Thin Loess and Till, Northern 212N Northern Minnesota Drift and Lake Plains 50 Northern Lakes and Forests 

Part 90A Wisconsin and Minnesota Thin Loess and Till, Northern 212K Western Superior Uplands 51 North Central Hardwood Forests 

Part 90B Wisconsin and Minnesota Thin Loess and Till, Southern 212Q North Central Wisconsin Uplands 51 North Central Hardwood Forests 

Part 90B Wisconsin and Minnesota Thin Loess and Till, Southern 212K Western Superior Uplands 51 North Central Hardwood Forests 

Part 90B Wisconsin and Minnesota Thin Loess and Till, Southern 222M Minnesota and Northeast Iowa Morainal-Oak 51 North Central Hardwood Forests 

Part Savannah 90B Wisconsin and Minnesota Thin Loess and Till, Southern 222M Minnesota and Northeast Iowa Morainal-Oak Part Savannah 47 Western Corn Belt Plains 

91A Central Minnesota Sandy Outwash 222M Minnesota and Northeast Iowa Morainal-Oak 51 North Central Hardwood Forests 

Savannah 91A Central Minnesota Sandy Outwash 212N Northern Minnesota Drift and Lake Plains 50 Northern Lakes and Forests 

91A Central Minnesota Sandy Outwash 251B North Central Glaciated Plains 51 North Central Hardwood Forests 

91A Central Minnesota Sandy Outwash 212N Northern Minnesota Drift and Lake Plains 51 North Central Hardwood Forests 

91B Wisconsin and Minnesota Sandy Outwash 212K Western Superior Uplands 50 Northern Lakes and Forests 

91B Wisconsin and Minnesota Sandy Outwash 222M Minnesota and Northeast Iowa Morainal-Oak 51 North Central Hardwood Forests 

Savannah 92 Superior Lake Plain 212Y Southwest Lake Superior Clay Plain 50 Northern Lakes and Forests 

92 Superior Lake Plain 212J Southern Superior Uplands 50 Northern Lakes and Forests 

92 Superior Lake Plain 212L Northern Superior Uplands 50 Northern Lakes and Forests 

93A Superior Stony and Rocky Loamy Plains and Hills, 212L Northern Superior Uplands 50 Northern Lakes and Forests 

Western Part 93B Superior Stony and Rocky Loamy Plains and Hills, 212S Northern Upper Peninsula 50 Northern Lakes and Forests 

Eastern Part 93B Superior Stony and Rocky Loamy Plains and Hills, 212J Southern Superior Uplands 50 Northern Lakes and Forests 

Eastern Part 94A Northern Michigan and Wisconsin Sandy Drift 212H Northern Lower Peninsula 50 Northern Lakes and Forests 

94A Northern Michigan and Wisconsin Sandy Drift 212H Northern Lower Peninsula 56 Southern Michigan/Northern Indiana Drift Pla

94B Michigan Eastern Upper Peninsula Sandy Drift 212R Eastern Upper Peninsula 50 Northern Lakes and Forests 

94B Michigan Eastern Upper Peninsula Sandy Drift 212T Northern Green Bay Lobe 50 Northern Lakes and Forests 
MLRA Forest Service Section EPA Level III Ecoregion 94C Michigan Northern Lower Peninsula Sandy Drift 212H Northern Lower Peninsula 50 Northern Lakes and Forests 

94D Northern Highland Sandy Drift 212X Northern Highlands 50 Northern Lakes and Forests 

95A Northeastern Wisconsin Drift Plain 212Z Green Bay-Manitowac Upland 53 Southeastern Wisconsin Till Plains 

95A Northeastern Wisconsin Drift Plain 212T Northern Green Bay Lobe 51 North Central Hardwood Forests 

95A Northeastern Wisconsin Drift Plain 222K Southwestern Great Lakes Morainal 53 Southeastern Wisconsin Till Plains 

95A Northeastern Wisconsin Drift Plain 212T Northern Green Bay Lobe 50 Northern Lakes and Forests 

95A Northeastern Wisconsin Drift Plain 212Z Green Bay-Manitowac Upland 51 North Central Hardwood Forests 

95B Southern Wisconsin and Northern Illinois Drift Plain 222K Southwestern Great Lakes Morainal 53 Southeastern Wisconsin Till Plains 

95B Southern Wisconsin and Northern Illinois Drift Plain 222K Southwestern Great Lakes Morainal 54 Central Corn Belt Plains 

95B Southern Wisconsin and Northern Illinois Drift Plain 222K Southwestern Great Lakes Morainal 51 North Central Hardwood Forests 

96 Western Michigan Fruit Belt 212H Northern Lower Peninsula 51 North Central Hardwood Forests 

96 Western Michigan Fruit Belt 212H Northern Lower Peninsula 50 Northern Lakes and Forests 

97 Southwestern Michigan Fruit and Truck Crop Belt 222J South Central Great Lakes 56 Southern Michigan/Northern Indiana Drift Pla

97 Southwestern Michigan Fruit and Truck Crop Belt 222K Southwestern Great Lakes Morainal 54 Central Corn Belt Plains 

97 Southwestern Michigan Fruit and Truck Crop Belt 222J South Central Great Lakes 54 Central Corn Belt Plains 

98 Southern Michigan and Northern Indiana Drift Plain 222J South Central Great Lakes 56 Southern Michigan/Northern Indiana Drift Pla

98 Southern Michigan and Northern Indiana Drift Plain 212H Northern Lower Peninsula 56 Southern Michigan/Northern Indiana Drift Pla

98 Southern Michigan and Northern Indiana Drift Plain 251D Central Till Plains and Grand Prairies 54 Central Corn Belt Plains 99 Erie-Huron Lake Plain 222U Lake Whittlesey Glacrolacustrine Plain 57 Huron/Erie Lake Plains 

99 Erie-Huron Lake Plain 222U Lake Whittlesey Glacrolacustrine Plain 56 Southern Michigan/Northern Indiana Drift Pla

99 Erie-Huron Lake Plain 222J South Central Great Lakes 56 Southern Michigan/Northern Indiana Drift Pla

101 Ontario-Erie Plain and Finger Lakes Region 222I Erie and Ontario Lake Plain 83 Eastern Great Lakes and Hudson Lowlands 

101 Ontario-Erie Plain and Finger Lakes Region 211J Tug Hill Plateau-Mohawk Valley 83 Eastern Great Lakes and Hudson Lowlands 

102A Rolling Till Prairie 251B North Central Glaciated Plains 46 Northern Glaciated Plains 

102A Rolling Till Prairie 222M Minnesota and Northeast Iowa Morainal-Oak Savannah 51 North Central Hardwood Forests 

102A Rolling Till Prairie 251A Red River Valley 51 North Central Hardwood Forests 

102A Rolling Till Prairie 251B North Central Glaciated Plains 51 North Central Hardwood Forests 

102B Till Plains 251B North Central Glaciated Plains 46 Northern Glaciated Plains 

102C Loess Uplands 251H Nebraska Rolling Hills 47 Western Corn Belt Plains 

102C Loess Uplands 251B North Central Glaciated Plains 47 Western Corn Belt Plains 

102C Loess Uplands 332C Nebraska Sand Hills 47 Western Corn Belt Plains 

102C Loess Uplands 332C Nebraska Sand Hills 27 Central Great Plains 

103 Central Iowa and Minnesota Till Prairies 251B North Central Glaciated Plains 47 Western Corn Belt Plains 

103 Central Iowa and Minnesota Till Prairies 222M Minnesota and Northeast Iowa Morainal-Oak Savannah 51 North Central Hardwood Forests 

103 Central Iowa and Minnesota Till Prairies 222M Minnesota and Northeast Iowa Morainal-Oak Savannah 47 Western Corn Belt Plains 

104 Eastern Iowa and Minnesota Till Prairies 222M Minnesota and Northeast Iowa Morainal-Oak Savannah 47 Western Corn Belt Plains 

104 Eastern Iowa and Minnesota Till Prairies 251C Central Dissected Till Plains 47 Western Corn Belt Plains 

104 Eastern Iowa and Minnesota Till Prairies 222L North Central U.S. Driftless and Escarpment 52 Driftless Area 

105 Northern Mississippi Valley Loess Hills 222L North Central U.S. Driftless and Escarpment 52 Driftless Area 

105 Northern Mississippi Valley Loess Hills 222L North Central U.S. Driftless and Escarpment 51 North Central Hardwood Forests 
MLRA Forest Service Section EPA Level III Ecoregion 106 Nebraska and Kansas Loess-Drift Hills 251H Nebraska Rolling Hills 47 Western Corn Belt Plains 

106 Nebraska and Kansas Loess-Drift Hills 251H Nebraska Rolling Hills 40 Central Irregular Plains 106 Nebraska and Kansas Loess-Drift Hills 251H Nebraska Rolling Hills 27 Central Great Plains 107A Iowa and Minnesota Loess Hills 251B North Central Glaciated Plains 47 Western Corn Belt Plains 

107B Iowa and Missouri Deep Loess Hills 251C Central Dissected Till Plains 47 Western Corn Belt Plains 107B Iowa and Missouri Deep Loess Hills 251H Nebraska Rolling Hills 47 Western Corn Belt Plains 108A Illinois and Iowa Deep Loess and Drift, Eastern Part 251D Central Till Plains and Grand Prairies 54 Central Corn Belt Plains 

108B Illinois and Iowa Deep Loess and Drift, East-Central Part 251D Central Till Plains and Grand Prairies 54 Central Corn Belt Plains 108B Illinois and Iowa Deep Loess and Drift, East-Central Part 251C Central Dissected Till Plains 54 Central Corn Belt Plains 108B Illinois and Iowa Deep Loess and Drift, East-Central Part 222K Southwestern Great Lakes Morainal 54 Central Corn Belt Plains 108C Illinois and Iowa Deep Loess and Drift, West-Central Part 251C Central Dissected Till Plains 47 Western Corn Belt Plains 108D Illinois and Iowa Deep Loess and Drift, Western Part 251C Central Dissected Till Plains 47 Western Corn Belt Plains 109 Iowa and Missouri Heavy Till Plain 251C Central Dissected Till Plains 40 Central Irregular Plains 

110 Northern Illinois and Indiana Heavy Till Plain 251D Central Till Plains and Grand Prairies 54 Central Corn Belt Plains 

110 Northern Illinois and Indiana Heavy Till Plain 222K Southwestern Great Lakes Morainal 54 Central Corn Belt Plains 

110 Northern Illinois and Indiana Heavy Till Plain 222K Southwestern Great Lakes Morainal 53 Southeastern Wisconsin Till Plains 

111A Indiana and Ohio Till Plain, Central Part 222H Central Till Plains-Beech-Maple 55 Eastern Corn Belt Plains 111B Indiana and Ohio Till Plain, Northeastern Part 222H Central Till Plains-Beech-Maple 55 Eastern Corn Belt Plains 111B Indiana and Ohio Till Plain, Northeastern Part 222J South Central Great Lakes 56 Southern Michigan/Northern Indiana Drift Pla111B Indiana and Ohio Till Plain, Northeastern Part 222J South Central Great Lakes 55 Eastern Corn Belt Plains 111C Indiana and Ohio Till Plain, Northwestern Part 222J South Central Great Lakes 56 Southern Michigan/Northern Indiana Drift Pla111C Indiana and Ohio Till Plain, Northwestern Part 251D Central Till Plains and Grand Prairies 54 Central Corn Belt Plains 111C Indiana and Ohio Till Plain, Northwestern Part 251D Central Till Plains and Grand Prairies 55 Eastern Corn Belt Plains 111D Indiana and Ohio Till Plain, Western Part 222H Central Till Plains-Beech-Maple 55 Eastern Corn Belt Plains 

111D Indiana and Ohio Till Plain, Western Part 251D Central Till Plains and Grand Prairies 54 Central Corn Belt Plains 

111E Indiana and Ohio Till Plain, Eastern Part 222H Central Till Plains-Beech-Maple 55 Eastern Corn Belt Plains 

111E Indiana and Ohio Till Plain, Eastern Part 221F Western Glaciated Allegheny Plateau 61 Erie Drift Plain 

112 Cherokee Prairies 251E Osage Plains 40 Central Irregular Plains 

112 Cherokee Prairies 255A Cross Timbers and Prairie 40 Central Irregular Plains 

113 Central Claypan Areas 223G Central Till Plains-Oak Hickory 72 Interior River Valleys and Hills 

113 Central Claypan Areas 251C Central Dissected Till Plains 40 Central Irregular Plains 

114A Southern Illinois and Indiana Thin Loess and Till Plain, 222H Central Till Plains-Beech-Maple 55 Eastern Corn Belt Plains 

Eastern Part 114A Southern Illinois and Indiana Thin Loess and Till Plain, 223G Central Till Plains-Oak Hickory 72 Interior River Valleys and Hills 

Eastern Part 114A Southern Illinois and Indiana Thin Loess and Till Plain, 221F Western Glaciated Allegheny Plateau 61 Erie Drift Plain 

Eastern Part 114A Southern Illinois and Indiana Thin Loess and Till Plain, 223B Interior Low Plateau-Transition Hills 71 Interior Plateau 

Eastern Part 114A Southern Illinois and Indiana Thin Loess and Till Plain, 223D Interior Low Plateau-Shawnee Hills 71 Interior Plateau Eastern Part
MLRA Forest Service Section EPA Level III Ecoregion 114B Southern Illinois and Indiana Thin Loess and Till Plain, 223G Central Till Plains-Oak Hickory 72 Interior River Valleys and Hills 

Western Part 114B Southern Illinois and Indiana Thin Loess and Till Plain, 223F Interior Low Plateau-Bluegrass 55 Eastern Corn Belt Plains 

Western Part 114B Southern Illinois and Indiana Thin Loess and Till Plain, 251C Central Dissected Till Plains 54 Central Corn Belt Plains 

Western Part 115A Central Mississippi Valley Wooded Slopes, Eastern Part 223G Central Till Plains-Oak Hickory 72 Interior River Valleys and Hills 

115A Central Mississippi Valley Wooded Slopes, Eastern Part 223D Interior Low Plateau-Shawnee Hills 72 Interior River Valleys and Hills 

115B Central Mississippi Valley Wooded Slopes, Western Part 223A Ozark Highlands 72 Interior River Valleys and Hills 

115B Central Mississippi Valley Wooded Slopes, Western Part 223A Ozark Highlands 39 Ozark Highlands 

115C Central Mississippi Valley Wooded Slopes, Northern Part 251C Central Dissected Till Plains 72 Interior River Valleys and Hills 

115C Central Mississippi Valley Wooded Slopes, Northern Part 251C Central Dissected Till Plains 54 Central Corn Belt Plains 

115C Central Mississippi Valley Wooded Slopes, Northern Part 251D Central Till Plains and Grand Prairies 54 Central Corn Belt Plains 

115C Central Mississippi Valley Wooded Slopes, Northern Part 251C Central Dissected Till Plains 40 Central Irregular Plains 

116A Ozark Highland 223A Ozark Highlands 39 Ozark Highlands 116B Springfield Plain 223A Ozark Highlands 39 Ozark Highlands 

116C St. Francois Knobs and Basins 223A Ozark Highlands 39 Ozark Highlands 

117 Boston Mountains M223A Boston Mountains 38 Boston Mountains 

117 Boston Mountains M223A Boston Mountains 37 Arkansas Valley 

118A Arkansas Valley and Ridges, Eastern Part 231G Arkansas Valley 37 Arkansas Valley 

118A Arkansas Valley and Ridges, Eastern Part M231A Ouachita Mountains 37 Arkansas Valley 

118B Arkansas Valley and Ridges, Western Part 231G Arkansas Valley 37 Arkansas Valley 

118B Arkansas Valley and Ridges, Western Part 255A Cross Timbers and Prairie 29 Cross Timbers 

118B Arkansas Valley and Ridges, Western Part 255A Cross Timbers and Prairie 37 Arkansas Valley 

118B Arkansas Valley and Ridges, Western Part 231G Arkansas Valley 29 Cross Timbers 

119 Ouachita Mountains M231A Ouachita Mountains 36 Ouachita Mountains 

119 Ouachita Mountains M231A Ouachita Mountains 37 Arkansas Valley 

119 Ouachita Mountains 231G Arkansas Valley 37 Arkansas Valley 120A Kentucky and Indiana Sandstone and Shale Hills and 223D Interior Low Plateau-Shawnee Hills 72 Interior River Valleys and Hills 

Valleys, Southern Part 120A Kentucky and Indiana Sandstone and Shale Hills and 223D Interior Low Plateau-Shawnee Hills 71 Interior Plateau 

Valleys, Southern Part 120B Kentucky and Indiana Sandstone and Shale Hills and 223D Interior Low Plateau-Shawnee Hills 71 Interior Plateau 

Valleys, Northwestern Part 120B Kentucky and Indiana Sandstone and Shale Hills and 223D Interior Low Plateau-Shawnee Hills 72 Interior River Valleys and Hills 

Valleys, Northwestern Part 120C Kentucky and Indiana Sandstone and Shale Hills and 223B Interior Low Plateau-Transition Hills 71 Interior Plateau 

Valleys, Northeastern Part 121 Kentucky Bluegrass 223F Interior Low Plateau-Bluegrass 71 Interior Plateau 

121 Kentucky Bluegrass 222H Central Till Plains-Beech-Maple 55 Eastern Corn Belt Plains 
MLRA Forest Service Section EPA Level III Ecoregion 122 Highland Rim and Pennyroyal 223E Interior Low Plateau-Highland Rim 71 Interior Plateau 

122 Highland Rim and Pennyroyal 223B Interior Low Plateau-Transition Hills 71 Interior Plateau 

123 Nashville Basin 223E Interior Low Plateau-Highland Rim 71 Interior Plateau 

124 Western Allegheny Plateau 221E Southern Unglaciated Allegheny Plateau 70 Western Allegheny Plateau 

124 Western Allegheny Plateau 221H Northern Cumberland Plateau 70 Western Allegheny Plateau 

125 Cumberland Plateau and Mountains M221C Northern Cumberland Mountains 69 Central Appalachians 

125 Cumberland Plateau and Mountains 221H Northern Cumberland Plateau 68 Southwestern Appalachians 

125 Cumberland Plateau and Mountains 221H Northern Cumberland Plateau 69 Central Appalachians 

126 Central Allegheny Plateau 221E Southern Unglaciated Allegheny Plateau 70 Western Allegheny Plateau 

127 Eastern Allegheny Plateau and Mountains M221B Allegheny Mountains 69 Central Appalachians 

127 Eastern Allegheny Plateau and Mountains 211G Northern Unglaciated Allegheny Plateau 62 North Central Appalachians 

127 Eastern Allegheny Plateau and Mountains M221B Allegheny Mountains 67 Ridge and Valley 

127 Eastern Allegheny Plateau and Mountains M221C Northern Cumberland Mountains 69 Central Appalachians 

127 Eastern Allegheny Plateau and Mountains 221E Southern Unglaciated Allegheny Plateau 69 Central Appalachians 

128 Southern Appalachian Ridges and Valleys 221J Central Ridge and Valley 67 Ridge and Valley 

128 Southern Appalachian Ridges and Valleys 231D Southern Ridge and Valley 67 Ridge and Valley 128 Southern Appalachian Ridges and Valleys M221A Northern Ridge and Valley 67 Ridge and Valley 129 Sand Mountain 231C Southern Cumberland Plateau 68 Southwestern Appalachians 

129 Sand Mountain 231C Southern Cumberland Plateau 71 Interior Plateau 

129 Sand Mountain 231B Coastal Plains-Middle 68 Southwestern Appalachians 

130A Northern Blue Ridge M221D Blue Ridge Mountains 66 Blue Ridge 130B Southern Blue Ridge M221D Blue Ridge Mountains 66 Blue Ridge 130B Southern Blue Ridge 231A Southern Appalachian Piedmont 66 Blue Ridge 

131A Southern Mississippi River Alluvium 234D White and Black River Alluvial Plains 73 Mississippi Alluvial Plain 

131A Southern Mississippi River Alluvium 234A Southern Mississippi Alluvial Plain 73 Mississippi Alluvial Plain 131A Southern Mississippi River Alluvium 234C Atchafalaya and Red River Alluvial Plains 73 Mississippi Alluvial Plain 

131A Southern Mississippi River Alluvium 232E Louisiana Coastal Prairie and Marshes 73 Mississippi Alluvial Plain 131B Arkansas River Alluvium 234E Arkansas Alluvial Plains 73 Mississippi Alluvial Plain 

131B Arkansas River Alluvium 234A Southern Mississippi Alluvial Plain 73 Mississippi Alluvial Plain 

131C Red River Alluvium 231E Mid Coastal Plains-Western 35 South Central Plains 131C Red River Alluvium 234C Atchafalaya and Red River Alluvial Plains 35 South Central Plains 

131C Red River Alluvium 232F Coastal Plains and Flatwoods-Western Gulf 35 South Central Plains 

131C Red River Alluvium 234C Atchafalaya and Red River Alluvial Plains 73 Mississippi Alluvial Plain 131D Southern Mississippi River Terraces 234E Arkansas Alluvial Plains 73 Mississippi Alluvial Plain 131D Southern Mississippi River Terraces 234E Arkansas Alluvial Plains 35 South Central Plains 

131D Southern Mississippi River Terraces 231E Mid Coastal Plains-Western 35 South Central Plains 

131D Southern Mississippi River Terraces 234A Southern Mississippi Alluvial Plain 35 South Central Plains 

133A Southern Coastal Plain 232B Gulf Coastal Plains and Flatwoods 65 Southeastern Plains 

133A Southern Coastal Plain 232J Southern Atlantic Coastal Plains and Flatwoods 65 Southeastern Plains 

133A Southern Coastal Plain 231B Coastal Plains-Middle 65 Southeastern Plains 

133A Southern Coastal Plain 232H Middle Atlantic Coastal Plains and Flatwoods 65 Southeastern Plains 

133A Southern Coastal Plain 231H Coastal Plains-Loess 65 Southeastern Plains 
MLRA Forest Service Section EPA Level III Ecoregion 133B Western Coastal Plain 231E Mid Coastal Plains-Western 35 South Central Plains 133B Western Coastal Plain 232F Coastal Plains and Flatwoods-Western Gulf 35 South Central Plains 134 Southern Mississippi Valley Loess 231H Coastal Plains-Loess 74 Mississippi Valley Loess Plains 134 Southern Mississippi Valley Loess 234D White and Black River Alluvial Plains 73 Mississippi Alluvial Plain 134 Southern Mississippi Valley Loess 231H Coastal Plains-Loess 65 Southeastern Plains 

134 Southern Mississippi Valley Loess 234D White and Black River Alluvial Plains 74 Mississippi Valley Loess Plains 

135A Alabama and Mississippi Blackland Prairie 231B Coastal Plains-Middle 65 Southeastern Plains 

135A Alabama and Mississippi Blackland Prairie 231H Coastal Plains-Loess 65 Southeastern Plains 

135B Cretaceous Western Coastal Plain 231E Mid Coastal Plains-Western 35 South Central Plains 136 Southern Piedmont 231I Central Appalachian Piedmont 45 Piedmont 

136 Southern Piedmont 231A Southern Appalachian Piedmont 45 Piedmont 137 Carolina and Georgia Sand Hills 232J Southern Atlantic Coastal Plains and Flatwoods 65 Southeastern Plains 

138 North-Central Florida Ridge 232K Florida Coastal Plains Central Highlands 65 Southeastern Plains 

138 North-Central Florida Ridge 232K Florida Coastal Plains Central Highlands 75 Southern Coastal Plain 

138 North-Central Florida Ridge 232J Southern Atlantic Coastal Plains and Flatwoods 65 Southeastern Plains 

139 Lake Erie Glaciated Plateau 221F Western Glaciated Allegheny Plateau 61 Erie Drift Plain 

139 Lake Erie Glaciated Plateau 222I Erie and Ontario Lake Plain 83 Eastern Great Lakes and Hudson Lowlands 

140 Glaciated Allegheny Plateau and Catskill Mountains 211F Northern Glaciated Allegheny Plateau 60 Northern Appalachian Plateau and Uplands 

140 Glaciated Allegheny Plateau and Catskill Mountains 211F Northern Glaciated Allegheny Plateau 62 North Central Appalachians 

140 Glaciated Allegheny Plateau and Catskill Mountains 211I Catskill Mountains 58 Northeastern Highlands 140 Glaciated Allegheny Plateau and Catskill Mountains 222I Erie and Ontario Lake Plain 83 Eastern Great Lakes and Hudson Lowlands 

141 Tughill Plateau 211J Tug Hill Plateau-Mohawk Valley 58 Northeastern Highlands 

141 Tughill Plateau 211J Tug Hill Plateau-Mohawk Valley 83 Eastern Great Lakes and Hudson Lowlands 

142 St. Lawrence-Champlain Plain 211E St. Lawrence and Champlain Valley 83 Eastern Great Lakes and Hudson Lowlands 

142 St. Lawrence-Champlain Plain M211D Adirondack Highlands 58 Northeastern Highlands 142 St. Lawrence-Champlain Plain 211J Tug Hill Plateau-Mohawk Valley 83 Eastern Great Lakes and Hudson Lowlands 

143 Northeastern Mountains M211A White Mountains 58 Northeastern Highlands 

143 Northeastern Mountains M211D Adirondack Highlands 58 Northeastern Highlands 

143 Northeastern Mountains 211B Maine-New Brunswick Foothills and Lowlands 82 Laurentian Plains and Hills 

143 Northeastern Mountains M211C Green-Taconic-Berkshire Mountains 58 Northeastern Highlands 

143 Northeastern Mountains 211A Aroostook Hills and Lowlands 82 Laurentian Plains and Hills 144A New England and Eastern New York Upland, Southern Part 221A Lower New England 59 Northeastern Coastal Zone 144A New England and Eastern New York Upland, Southern Part 221B Hudson Valley 83 Eastern Great Lakes and Hudson Lowlands 

144A New England and Eastern New York Upland, Southern Part 221A Lower New England 58 Northeastern Highlands 

144B New England and Eastern New York Upland, Northern Part 211D Central Maine Coastal and Embayment 82 Laurentian Plains and Hills 

144B New England and Eastern New York Upland, Northern Part M211B New England Piedmont 58 Northeastern Highlands 

144B New England and Eastern New York Upland, Northern Part 221A Lower New England 58 Northeastern Highlands 

144B New England and Eastern New York Upland, Northern Part 211C Fundy Coastal and Interior 82 Laurentian Plains and Hills 

144B New England and Eastern New York Upland, Northern Part M211A White Mountains 58 Northeastern Highlands 

145 Connecticut Valley 221A Lower New England 59 Northeastern Coastal Zone 145 Connecticut Valley M211B New England Piedmont 58 Northeastern Highlands 146 Aroostook Area 211A Aroostook Hills and Lowlands 82 Laurentian Plains and Hills 

146 Aroostook Area M211A White Mountains 82 Laurentian Plains and Hills 
MLRA Forest Service Section EPA Level III Ecoregion 147 Northern Appalachian Ridges and Valleys M221A Northern Ridge and Valley 67 Ridge and Valley 147 Northern Appalachian Ridges and Valleys M221B Allegheny Mountains 67 Ridge and Valley 

148 Northern Piedmont 221D Northern Appalachian Piedmont 64 Northern Piedmont 

149A Northern Coastal Plain 232A Northern Atlantic Coastal Plain 65 Southeastern Plains 

149A Northern Coastal Plain 232A Northern Atlantic Coastal Plain 84 Atlantic Coastal Pine Barrens 149A Northern Coastal Plain 232A Northern Atlantic Coastal Plain 63 Middle Atlantic Coastal Plain 149B Long Island-Cape Cod Coastal Lowland 221A Lower New England 84 Atlantic Coastal Pine Barrens 150A Gulf Coast Prairies 255D Central Gulf Prairie and Marshes 34 Western Gulf Coastal Plain 

150A Gulf Coast Prairies 232E Louisiana Coastal Prairie and Marshes 34 Western Gulf Coastal Plain 

150B Gulf Coast Saline Prairies 255D Central Gulf Prairie and Marshes 34 Western Gulf Coastal Plain 150B Gulf Coast Saline Prairies Water Water 0 NULL 150B Gulf Coast Saline Prairies 232E Louisiana Coastal Prairie and Marshes 34 Western Gulf Coastal Plain 150B Gulf Coast Saline Prairies 315E Rio Grande Plain 34 Western Gulf Coastal Plain 151 Gulf Coast Marsh 232E Louisiana Coastal Prairie and Marshes 73 Mississippi Alluvial Plain 

151 Gulf Coast Marsh 232E Louisiana Coastal Prairie and Marshes 34 Western Gulf Coastal Plain 

151 Gulf Coast Marsh Water Water 0 NULL 

152A Eastern Gulf Coast Flatwoods 232L Gulf Coastal Lowlands 75 Southern Coastal Plain 152A Eastern Gulf Coast Flatwoods 232D Florida Coastal Lowlands-Gulf 75 Southern Coastal Plain 152A Eastern Gulf Coast Flatwoods 232B Gulf Coastal Plains and Flatwoods 75 Southern Coastal Plain 152B Western Gulf Coast Flatwoods 232F Coastal Plains and Flatwoods-Western Gulf 35 South Central Plains 152B Western Gulf Coast Flatwoods 232E Louisiana Coastal Prairie and Marshes 35 South Central Plains 153A Atlantic Coast Flatwoods 232C Atlantic Coastal Flatwoods 63 Middle Atlantic Coastal Plain 

153A Atlantic Coast Flatwoods 232C Atlantic Coastal Flatwoods 75 Southern Coastal Plain 

153A Atlantic Coast Flatwoods 232I Northern Atlantic Coastal Flatwoods 63 Middle Atlantic Coastal Plain 153A Atlantic Coast Flatwoods 232H Middle Atlantic Coastal Plains and Flatwoods 63 Middle Atlantic Coastal Plain 153B Tidewater Area 232I Northern Atlantic Coastal Flatwoods 63 Middle Atlantic Coastal Plain 

153B Tidewater Area 232C Atlantic Coastal Flatwoods 75 Southern Coastal Plain 

153B Tidewater Area 232H Middle Atlantic Coastal Plains and Flatwoods 63 Middle Atlantic Coastal Plain 

153C Mid-Atlantic Coastal Plain 232H Middle Atlantic Coastal Plains and Flatwoods 63 Middle Atlantic Coastal Plain 

153C Mid-Atlantic Coastal Plain 232A Northern Atlantic Coastal Plain 63 Middle Atlantic Coastal Plain 

153D Northern Tidewater Area 232H Middle Atlantic Coastal Plains and Flatwoods 63 Middle Atlantic Coastal Plain 

153D Northern Tidewater Area 232A Northern Atlantic Coastal Plain 84 Atlantic Coastal Pine Barrens 

154 South-Central Florida Ridge 232K Florida Coastal Plains Central Highlands 75 Southern Coastal Plain 

154 South-Central Florida Ridge 232D Florida Coastal Lowlands-Gulf 75 Southern Coastal Plain 

154 South-Central Florida Ridge 232G Florida Coastal Lowlands-Atlantic 75 Southern Coastal Plain 

155 Southern Florida Flatwoods 232G Florida Coastal Lowlands-Atlantic 75 Southern Coastal Plain 155 Southern Florida Flatwoods 232D Florida Coastal Lowlands-Gulf 75 Southern Coastal Plain 155 Southern Florida Flatwoods 232K Florida Coastal Plains Central Highlands 75 Southern Coastal Plain 155 Southern Florida Flatwoods 411A Everglades 76 Southern Florida Coastal Plain 

156A Florida Everglades and Associated Areas 411A Everglades 76 Southern Florida Coastal Plain 

156B Southern Florida Lowlands 232G Florida Coastal Lowlands-Atlantic 75 Southern Coastal Plain 
of the United States 655

Area and Proportionate Extent of the Land Resource Regions and Major Land Resource Areas

(MLRAs 33, 37, 45, 50, 59, 68, 100, and 132, described in earlier versions of Agriculture Handbook 296, are not listed separately

because they have been incorporated into other MLRAs. There are currently no MLRAs 168-189, 198-219, or 247-269.)

 Extent in—

Land resource region and major land resource area Area United

LRR States

 mi2 km2 pct pct

A—Northwestern Forest, Forage, and Specialty Crop Region .......................................... 90,165 233,635 --- 2.51

1—Northern Pacific Coast Range, Foothills, and Valleys ............................................. 10,295 26,675 11.4 0.29

2—Willamette and Puget Sound Valleys ....................................................................... 12,210 31,640 13.5 0.34

3—Olympic and Cascade Mountains ............................................................................ 24,375 63,170 27.0 0.68

4A—Sitka Spruce Belt ..................................................................................................... 5,305 13,740 5.9 0.15

4B—Coastal Redwood Belt ............................................................................................. 4,670 12,095 5.2 0.13

5—Siskiyou-Trinity Area ............................................................................................... 20,150 52,215 22.3 0.56

6—Cascade Mountains, Eastern Slope .......................................................................... 13,160 34,100 14.6 0.37

B—Northwestern Wheat and Range Region ..................................................................... 81,255 210,555 --- 2.26

7—Columbia Basin .......................................................................................................... 6,610 17,130 8.1 0.18

8—Columbia Plateau ..................................................................................................... 18,505 47,955 22.8 0.52

9—Palouse and Nez Perce Prairies ................................................................................... 8,810 22,825 10.8 0.25

10—Central Rocky and Blue Mountain Foothills ........................................................ 17,515 45,385 21.6 0.49

11—Snake River Plains ................................................................................................. 16,475 42,685 20.3 0.46

12—Lost River Valleys and Mountains ........................................................................... 6,070 15,735 7.5 0.17

13—Eastern Idaho Plateaus ............................................................................................. 7,270 18,840 8.9 0.20

C—California Subtropical Fruit, Truck, and Specialty Crop Region ............................... 62,350 161,570 --- 1.74

14—Central California Coastal Valleys ........................................................................... 3,170 8,215 5.1 0.09

15—Central California Coast Range ............................................................................. 17,840 46,235 28.6 0.50

16—California Delta ........................................................................................................... 805 2,080 1.3 0.02

17—Sacramento and San Joaquin Valleys ..................................................................... 18,650 48,330 29.9 0.52

18—Sierra Nevada Foothills ............................................................................................ 8,160 21,145 13.1 0.23

19—Southern California Coastal Plain ........................................................................... 4,120 10,675 6.6 0.11

20—Southern California Mountains ............................................................................... 9,605 24,890 15.4 0.27

D—Western Range and Irrigated Region ......................................................................... 549,725 1,424,480 --- 15.30

21—Klamath and Shasta Valleys and Basins ................................................................. 11,495 29,790 2.1 0.32

22A—Sierra Nevada Mountains .................................................................................... 18,810 48,745 3.4 0.52

22B—Southern Cascade Mountains ................................................................................ 5,855 15,175 1.1 0.16

23—Malheur High Plateau ............................................................................................ 22,895 59,320 4.2 0.64

24—Humboldt Area ....................................................................................................... 12,680 32,855 2.3 0.35

25—Owyhee High Plateau ............................................................................................. 28,930 74,960 5.3 0.81

26—Carson Basin and Mountains ................................................................................... 6,520 16,890 1.2 0.18

27—Fallon-Lovelock Area ............................................................................................. 12,565 32,560 2.3 0.35

28A—Great Salt Lake Area ............................................................................................ 36,775 95,300 6.7 1.02

28B—Central Nevada Basin and Range ........................................................................ 23,555 61,035 4.3 0.66

29—Southern Nevada Basin and Range ........................................................................ 26,295 68,140 4.8 0.73

30—Mojave Desert ........................................................................................................ 43,750 113,370 8.0 1.22

Appendix II.—Area of LRRs and MLRAs
656 Major Land Resource Areas

Area and Proportionate Extent of the Land Resource Regions and Major Land Resource Areas—Cont.

 Extent in—

Land resource region and major land resource area Area United

LRR States

 mi2 km2 pct pct

D—Western Range and Irrigated Region—Cont.

31—Lower Colorado Desert ........................................................................................... 11,615 30,100 2.1 0.32

32—Northern Intermountain Desertic Basins .................................................................. 8,910 23,080 1.6 0.25

34A—Cool Central Desertic Basins and Plateaus ......................................................... 33,005 85,525 6.0 0.92

34B—Warm Central Desertic Basins and Plateaus ........................................................ 12,850 33,290 2.3 0.36

35—Colorado Plateau .................................................................................................... 71,735 185,885 13.0 2.00

36—Southwestern Plateaus, Mesas, and Foothills ........................................................ 23,885 61,895 4.3 0.66

38—Mogollon Transition .............................................................................................. 18,985 49,195 3.5 0.53

39—Arizona and New Mexico Mountains .................................................................... 15,150 39,255 2.8 0.42

40—Sonoran Basin and Range ...................................................................................... 31,765 82,310 5.8 0.88

41—Southeastern Arizona Basin and Range ................................................................. 15,730 40,765 2.9 0.44

42—Southern Desertic Basins, Plains, and Mountains ................................................. 55,970 145,040 10.2 1.56

E—Rocky Mountain Range and Forest Region .............................................................. 236,510 612,875 --- 6.58

43A—Northern Rocky Mountains ................................................................................. 31,435 81,460 13.3 0.88

43B—Central Rocky Mountains ................................................................................... 75,915 196,715 32.1 2.11

43C—Blue and Seven Devils Mountains ...................................................................... 14,000 36,275 5.9 0.39

44—Northern Rocky Mountain Valleys ........................................................................ 12,830 33,245 5.4 0.36

46—Northern Rocky Mountain Foothills ..................................................................... 15,100 39,130 6.4 0.42

47—Wasatch and Uinta Mountains ............................................................................... 23,825 61,740 10.1 0.66

48A—Southern Rocky Mountains ................................................................................ 45,920 119,000 19.4 1.28

48B—Southern Rocky Mountain Parks .......................................................................... 2,325 6,020 1.0 0.06

49—Southern Rocky Mountain Foothills ..................................................................... 11,130 28,845 4.7 0.31

51—High Intermountain Valleys ..................................................................................... 4,030 10,445 1.7 0.11

F—Northern Great Plains Spring Wheat Region ............................................................. 142,225 368,535 --- 3.96

52—Brown Glaciated Plain ........................................................................................... 23,040 59,700 16.2 0.64

53A—Northern Dark Brown Glaciated Plains ................................................................. 9,220 23,885 6.5 0.26

53B—Central Dark Brown Glaciated Plains .................................................................. 19,640 50,900 13.8 0.55

53C—Southern Dark Brown Glaciated Plains ................................................................. 3,990 10,340 2.8 0.11

54—Rolling Soft Shale Plain ......................................................................................... 29,280 75,870 20.6 0.82

55A—Northern Black Glaciated Plains ......................................................................... 12,765 33,075 9.0 0.36

55B—Central Black Glaciated Plains ............................................................................ 17,155 44,455 12.1 0.48

55C—Southern Black Glaciated Plains ......................................................................... 10,835 28,075 7.6 0.30

56—Red River Valley of the North ................................................................................ 16,300 42,235 11.5 0.45

G—Western Great Plains Range and Irrigated Region .................................................... 213,945 554,395 --- 5.96

58A—Northern Rolling High Plains, Northern Part ...................................................... 42,350 109,740 19.8 1.18

58B—Northern Rolling High Plains, Southern Part ...................................................... 19,265 49,915 9.0 0.54

58C—Northern Rolling High Plains, Northeastern Part .................................................. 2,320 6,015 1.1 0.06

58D—Northern Rolling High Plains, Eastern Part ........................................................... 2,755 7,145 1.3 0.08

60A—Pierre Shale Plains ............................................................................................... 10,150 26,295 4.7 0.28

60B—Pierre Shale Plains, Northern Part .......................................................................... 3,375 8,750 1.6 0.09

61—Black Hills Foot Slopes ............................................................................................ 1,865 4,840 0.9 0.05

62—Black Hills ................................................................................................................ 3,040 7,875 1.4 0.08

63A—Northern Rolling Pierre Shale Plains ................................................................... 10,160 26,330 4.7 0.28

63B—Southern Rolling Pierre Shale Plains .................................................................... 4,460 11,565 2.1 0.12
of the United States 657

Area and Proportionate Extent of the Land Resource Regions and Major Land Resource Areas—Cont.

 Extent in—

Land resource region and major land resource area Area United

LRR States

 mi2 km2 pct pct

G—Western Great Plains Range and Irrigated Region—Cont.

64—Mixed Sandy and Silty Tableland and Badlands .................................................. 11,895 30,825 5.6 0.33

65—Nebraska Sand Hills ............................................................................................... 20,545 53,235 9.6 0.57

66—Dakota-Nebraska Eroded Tableland ........................................................................ 5,660 14,665 2.6 0.16

67A—Central High Plains, Northern Part ........................................................................ 8,165 21,150 3.8 0.23

67B—Central High Plains, Southern Part ...................................................................... 19,855 51,445 9.3 0.55

69—Upper Arkansas Valley Rolling Plains ................................................................... 11,920 30,885 5.6 0.33

70A—Canadian River Plains and Valleys...................................................................... 10,770 27,910 5.0 0.30

70B—Upper Pecos River Valley ...................................................................................... 9,900 25,660 4.6 0.28

70C—Central New Mexico Highlands .......................................................................... 12,495 32,375 5.8 0.35

70D—Southern Desert Foothills ...................................................................................... 3,000 7,775 1.4 0.08

H—Central Great Plains Winter Wheat and Range Region ............................................. 219,740 569,420 --- 6.12

71—Central Nebraska Loess Hills ................................................................................... 8,165 21,160 3.7 0.23

72—Central High Tableland .......................................................................................... 34,550 89,535 15.7 0.96

73—Rolling Plains and Breaks ...................................................................................... 21,485 55,670 9.8 0.60

74—Central Kansas Sandstone Hills ............................................................................... 8,365 21,675 3.8 0.23

75—Central Loess Plains ................................................................................................. 8,055 20,870 3.7 0.22

76—Bluestem Hills .......................................................................................................... 7,555 19,585 3.4 0.21

77A—Southern High Plains, Northern Part ................................................................... 10,005 25,930 4.6 0.28

77B—Southern High Plains, Northwestern Part .............................................................. 3,930 10,185 1.8 0.11

77C—Southern High Plains, Southern Part ................................................................... 20,955 54,300 9.5 0.58

77D—Southern High Plains, Southwestern Part .............................................................. 9,905 25,665 4.5 0.28

77E—Southern High Plains, Breaks .............................................................................. 10,320 26,735 4.7 0.29

78A—Rolling Limestone Prairie ..................................................................................... 4,750 12,310 2.2 0.13

78B—Central Rolling Red Plains, Western Part ............................................................ 18,610 48,220 8.5 0.52

78C—Central Rolling Red Plains, Eastern Part ............................................................. 19,565 50,705 8.9 0.54

79—Great Bend Sand Plains ............................................................................................ 7,405 19,185 3.4 0.21

80A—Central Rolling Red Prairies ............................................................................... 19,925 51,635 9.1 0.55

80B—Texas North-Central Prairies .................................................................................. 6,195 16,055 2.8 0.17

I—Southwest Plateaus and Plains Range and Cotton Region ........................................... 72,340 187,460 --- 2.01

81A—Edwards Plateau, Western Part ............................................................................. 16,550 42,885 22.9 0.46

81B—Edwards Plateau, Central Part .............................................................................. 11,125 28,825 15.4 0.31

81C—Edwards Plateau, Eastern Part ................................................................................ 8,060 20,890 11.1 0.22

81D—Southern Edwards Plateau ..................................................................................... 2,495 6,465 3.4 0.07

82A—Texas Central Basin ............................................................................................... 2,635 6,830 3.6 0.07

83A—Northern Rio Grande Plain .................................................................................. 11,115 28,805 15.4 0.31

83B—Western Rio Grande Plain ...................................................................................... 9,285 24,060 12.8 0.26

83C—Central Rio Grande Plain ....................................................................................... 4,275 11,075 5.9 0.12

83D—Lower Rio Grande Plain ........................................................................................ 2,500 6,475 3.5 0.07

83E—Sandsheet Prairie .................................................................................................... 4,300 11,150 5.9 0.12

J—Southwestern Prairies Cotton and Forage Region ........................................................ 59,700 154,695 --- 1.66

82B—Wichita Mountains ................................................................................................ 1,060 2,740 1.8 0.03

84A—North Cross Timbers .............................................................................................. 7,705 19,965 12.9 0.21

84B—West Cross Timbers ................................................................................................ 6,165 15,970 10.3 0.17
658 Major Land Resource Areas

Area and Proportionate Extent of the Land Resource Regions and Major Land Resource Areas—Cont.

 Extent in—

Land resource region and major land resource area Area United

LRR States

 mi2 km2 pct pct

J—Southwestern Prairies Cotton and Forage Region—Cont.

84C—East Cross Timbers ................................................................................................ 1,320 3,425 2.2 0.04

85—Grand Prairie ........................................................................................................... 10,400 26,955 17.4 0.29

86A—Texas Blackland Prairie, Northern Part ................................................................ 15,110 39,150 25.3 0.42

86B—Texas Blackland Prairie, Southern Part ................................................................. 2,925 7,585 4.9 0.08

87A—Texas Claypan Area, Southern Part ...................................................................... 10,535 27,295 17.6 0.29

87B—Texas Claypan Area, Northern Part ........................................................................ 4,480 11,610 7.5 0.12

K—Northern Lake States Forest and Forage Region ....................................................... 118,775 307,795 --- 3.31

57—Northern Minnesota Gray Drift ................................................................................ 9,785 25,355 8.2 0.27

88—Northern Minnesota Glacial Lake Basins .............................................................. 11,695 30,300 9.8 0.33

89—Wisconsin Central Sands .......................................................................................... 3,420 8,860 2.9 0.10

90A—Wisconsin and Minnesota Thin Loess and Till, Northern Part ........................... 17,535 45,440 14.8 0.49

90B—Wisconsin and Minnesota Thin Loess and Till, Southern Part ............................. 8,935 23,155 7.5 0.25

91A—Central Minnesota Sandy Outwash ....................................................................... 4,600 11,920 3.9 0.13

91B—Wisconsin and Minnesota Sandy Outwash ........................................................... 4,110 10,650 3.5 0.11

92—Superior Lake Plain .................................................................................................. 2,920 7,570 2.5 0.08

93A—Superior Stony and Rocky Loamy Plains and Hills, Western Part ........................ 8,570 22,205 7.2 0.24

93B—Superior Stony and Rocky Loamy Plains and Hills, Eastern Part ......................... 6,900 17,880 5.8 0.19

94A—Northern Michigan and Wisconsin Sandy Drift .................................................... 9,020 23,380 7.6 0.25

94B—Michigan Eastern Upper Peninsula Sandy Drift ................................................... 9,810 25,425 8.3 0.27

94C—Michigan Northern Lower Peninsula Sandy Drift ................................................. 2,000 5,185 1.7 0.06

94D—Northern Highland Sandy Drift ............................................................................. 2,100 5,445 1.8 0.06

95A—Northeastern Wisconsin Drift Plain ....................................................................... 6,495 16,825 5.5 0.18

95B—Southern Wisconsin and Northern Illinois Drift Plain ........................................ 10,880 28,200 9.2 0.30

L—Lake States Fruit, Truck Crop, and Dairy Region ....................................................... 45,715 118,460 --- 1.27

96—Western Michigan Fruit Belt .................................................................................... 2,790 7,230 6.1 0.08

97—Southwestern Michigan Fruit and Truck Crop Belt ................................................ 3,085 7,995 6.7 0.09

98—Southern Michigan and Northern Indiana Drift Plain ........................................... 18,930 49,050 41.4 0.53

99—Erie-Huron Lake Plain ............................................................................................ 10,950 28,370 24.0 0.30

101—Ontario-Erie Plain and Finger Lakes Region ......................................................... 9,960 25,815 21.8 0.28

M—Central Feed Grains and Livestock Region.............................................................. 282,450 731,905 --- 7.86

102A—Rolling Till Prairie ............................................................................................ 16,545 42,870 5.9 0.46

102B—Till Plains ............................................................................................................ 2,215 5,735 0.8 0.06

102C—Loess Uplands .................................................................................................... 11,445 29,655 4.1 0.32

103—Central Iowa and Minnesota Till Prairies ............................................................ 27,640 71,630 9.8 0.77

104—Eastern Iowa and Minnesota Till Prairies .............................................................. 9,660 25,040 3.4 0.27

105—Northern Mississippi Valley Loess Hills .............................................................. 17,950 46,515 6.4 0.50

106—Nebraska and Kansas Loess-Drift Hills ................................................................ 10,920 28,295 3.9 0.30

107A—Iowa and Minnesota Loess Hills ......................................................................... 4,470 11,590 1.6 0.12

107B—Iowa and Missouri Deep Loess Hills ................................................................. 14,410 37,335 5.1 0.40

108A—Illinois and Iowa Deep Loess and Drift, Eastern Part ........................................ 11,145 28,875 3.9 0.31

108B—Illinois and Iowa Deep Loess and Drift, East-Central Part .................................. 7,450 19,300 2.6 0.21
of the United States 659

Area and Proportionate Extent of the Land Resource Regions and Major Land Resource Areas—Cont.

 Extent in—

Land resource region and major land resource area Area United

LRR States

 mi2 km2 pct pct

M—Central Feed Grains and Livestock Region—Cont.

108C—Illinois and Iowa Deep Loess and Drift, West-Central Part ................................. 9,805 25,405 3.5 0.27

108D—Illinois and Iowa Deep Loess and Drift, Western Part ......................................... 5,480 14,195 1.9 0.15

109—Iowa and Missouri Heavy Till Plain .................................................................... 15,895 41,185 5.6 0.44

110—Northern Illinois and Indiana Heavy Till Plain ..................................................... 7,535 19,525 2.7 0.21

111A—Indiana and Ohio Till Plain, Central Part .......................................................... 10,980 28,445 3.9 0.31

111B—Indiana and Ohio Till Plain, Northeastern Part ................................................. 13,460 34,880 4.8 0.37

111C—Indiana and Ohio Till Plain, Northwestern Part .................................................. 3,500 9,065 1.2 0.10

111D—Indiana and Ohio Till Plain, Western Part ........................................................... 5,355 13,880 1.9 0.15

111E—Indiana and Ohio Till Plain, Eastern Part ............................................................ 2,980 7,720 1.1 0.08

112—Cherokee Prairies ................................................................................................. 23,840 61,775 8.4 0.66

113—Central Claypan Areas .......................................................................................... 12,790 33,150 4.5 0.36

114A—Southern Illinois and Indiana Thin Loess and Till Plain, Eastern Part ............... 4,550 11,795 1.6 0.13

114B—Southern Illinois and Indiana Thin Loess and Till Plain, Western Part .............. 7,005 18,150 2.5 0.20

115A—Central Mississippi Valley Wooded Slopes, Eastern Part .................................... 3,690 9,565 1.3 0.10

115B—Central Mississippi Valley Wooded Slopes, Western Part ................................... 8,085 20,955 2.9 0.23

115C—Central Mississippi Valley Wooded Slopes, Northern Part ............................... 13,650 35,375 4.8 0.38

N—East and Central Farming and Forest Region ............................................................ 236,415 612,645 --- 6.58

116A—Ozark Highland ................................................................................................. 32,845 85,110 13.9 0.91

116B—Springfield Plain .................................................................................................. 5,130 13,300 2.2 0.14

116C—St. Francois Knobs and Basins ............................................................................ 1,600 4,150 0.7 0.04

117—Boston Mountains.................................................................................................. 6,850 17,755 2.9 0.19

118A—Arkansas Valley and Ridges, Eastern Part ........................................................... 6,755 17,510 2.9 0.19

118B—Arkansas Valley and Ridges, Western Part .......................................................... 3,070 7,960 1.3 0.09

119—Ouachita Mountains ............................................................................................. 11,885 30,800 5.0 0.33

120A—Kentucky and Indiana Sandstone and Shale Hills and Valleys,

Southern Part ................................................................................................................ 8,905 23,080 3.8 0.25

120B—Kentucky and Indiana Sandstone and Shale Hills and Valleys,

Northwestern Part ......................................................................................................... 3,040 7,875 1.3 0.08

120C—Kentucky and Indiana Sandstone and Shale Hills and Valleys,

Northeastern Part .......................................................................................................... 1,050 2,725 0.4 0.03

121—Kentucky Bluegrass ............................................................................................. 10,680 27,670 4.5 0.30

122—Highland Rim and Pennyroyal ............................................................................ 21,530 55,790 9.1 0.60

123—Nashville Basin ...................................................................................................... 5,625 14,580 2.4 0.16

124—Western Allegheny Plateau .................................................................................. 12,880 33,375 5.4 0.36

125—Cumberland Plateau and Mountains ................................................................... 20,330 52,685 8.6 0.57

126—Central Allegheny Plateau ................................................................................... 18,040 46,750 7.6 0.50

127—Eastern Allegheny Plateau and Mountains .......................................................... 19,440 50,370 8.2 0.54

128—Southern Appalachian Ridges and Valleys .......................................................... 21,095 54,660 8.9 0.59

129—Sand Mountain ....................................................................................................... 8,030 20,805 3.4 0.22

130A—Northern Blue Ridge ........................................................................................... 1,555 4,030 0.7 0.04

130B—Southern Blue Ridge ......................................................................................... 16,080 41,665 6.8 0.45
660

Area and Proportionate Extent of the Land Resource Regions and Major Land Resource Areas—Cont.

 Extent in—

Land resource region and major land resource area Area United

LRR States

 mi2 km2 pct pct

O—Mississippi Delta Cotton and Feed Grains Region ..................................................... 38,865 100,710 --- 1.08

131A—Southern Mississippi River Alluvium ............................................................... 29,555 76,585 76.0 0.82

131B—Arkansas River Alluvium .................................................................................... 3,955 10,245 10.2 0.11

131C—Red River Alluvium ............................................................................................. 2,410 6,245 6.2 0.07

131D—Southern Mississippi River Terraces ................................................................... 2,945 7,635 7.6 0.08

P—South Atlantic and Gulf Slope Cash Crops, Forest, and Livestock Region .............. 264,095 684,340 --- 7.35

133A—Southern Coastal Plain .................................................................................... 106,485 275,930 40.3 2.96

133B—Western Coastal Plain ........................................................................................ 45,450 117,770 17.2 1.27

134—Southern Mississippi Valley Loess ...................................................................... 26,520 68,715 10.0 0.74

135A—Alabama and Mississippi Blackland Prairie ....................................................... 6,370 16,510 2.4 0.18

135B—Cretaceous Western Coastal Plain ....................................................................... 3,970 10,290 1.5 0.11

136—Southern Piedmont ............................................................................................... 64,395 166,865 24.4 1.79

137—Carolina and Georgia Sand Hills ........................................................................... 8,665 22,450 3.3 0.24

138—North-Central Florida Ridge .................................................................................. 2,240 5,810 0.8 0.06

Q—Pacific Basin Region ........................................................................................................ 999 2,585 --- ---

190—Stratovolcanoes of the Mariana Islands .......................................................................71 183 7.1 ---

191—High Limestone Plateaus of the Mariana Islands ...................................................... 256 663 25.6 ---

192—Volcanic Highlands of the Mariana Islands .................................................................78 202 7.8 ---

193—Volcanic Islands of Western Micronesia ................................................................... 196 508 19.6 ---

194—Low Limestone Islands of Western Micronesia ...........................................................27 70 2.7 ---

195—Volcanic Islands of Central and Eastern Micronesia ................................................ 224 580 22.4 ---

196—Coral Atolls of Micronesia ...........................................................................................70 180 7.0 ---

197—Volcanic Islands of American Samoa ...........................................................................77 199 7.7 ---

R—Northeastern Forage and Forest Region .................................................................... 120,635 312,625 --- 3.36

139—Lake Erie Glaciated Plateau ................................................................................. 10,715 27,770 8.9 0.30

140—Glaciated Allegheny Plateau and Catskill Mountains ........................................ 22,370 57,975 18.5 0.62

141—Tughill Plateau ....................................................................................................... 1,175 3,045 1.0 0.03

142—St. Lawrence-Champlain Plain ............................................................................... 7,040 18,240 5.8 0.20

143—Northeastern Mountains....................................................................................... 36,840 95,465 30.5 1.03

144A—New England and Eastern New York Upland, Southern Part ............................ 18,590 48,180 15.4 0.52

144B—New England and Eastern New York Upland, Northern Part ............................. 20,500 53,125 17.0 0.57

145—Connecticut Valley ................................................................................................. 2,130 5,520 1.8 0.06

146—Aroostook Area ....................................................................................................... 1,275 3,305 1.1 0.04

S—Northern Atlantic Slope Diversified Farming Region ................................................. 40,865 105,905 --- 1.14

147—Northern Appalachian Ridges and Valleys .......................................................... 20,750 53,775 50.8 0.58

148—Northern Piedmont ............................................................................................... 12,800 33,170 31.3 0.36

149A—Northern Coastal Plain ........................................................................................ 5,205 13,495 12.7 0.14

149B—Long Island-Cape Cod Coastal Lowland ............................................................ 2,110 5,465 5.2 0.06
661

Area and Proportionate Extent of the Land Resource Regions and Major Land Resource Areas—Cont.

 Extent in—

Land resource region and major land resource area Area United

LRR States

 mi2 km2 pct pct

T—Atlantic and Gulf Coast Lowland Forest and Crop Region ........................................ 92,630 240,055 --- 2.58

150A—Gulf Coast Prairies ............................................................................................. 16,365 42,410 17.7 0.46

150B—Gulf Coast Saline Prairies .................................................................................... 3,420 8,865 3.7 0.10

151—Gulf Coast Marsh ................................................................................................... 8,495 22,015 9.2 0.24

152A—Eastern Gulf Coast Flatwoods ............................................................................. 9,860 25,555 10.6 0.27

152B—Western Gulf Coast Flatwoods ............................................................................ 5,880 15,240 6.3 0.16

153A—Atlantic Coast Flatwoods .................................................................................. 28,720 74,420 31.0 0.80

153B—Tidewater Area ................................................................................................... 12,830 33,250 13.9 0.36

153C—Mid-Atlantic Coastal Plain ................................................................................. 2,015 5,225 2.2 0.06

153D—Northern Tidewater Area ...................................................................................... 5,045 13,075 5.4 0.14

U—Florida Subtropical Fruit, Truck Crop, and Range Region ......................................... 35,610 92,275 --- 0.99

154—South-Central Florida Ridge .................................................................................. 8,285 21,470 23.3 0.23

155—Southern Florida Flatwoods ................................................................................. 18,575 48,135 52.2 0.52

156A—Florida Everglades and Associated Areas ............................................................ 6,915 17,920 19.4 0.19

156B—Southern Florida Lowlands ................................................................................. 1,835 4,750 5.2 0.05

V—Hawaii Region ............................................................................................................... 6,265 16,260 --- 0.17

157—Arid and Semiarid Low Mountain Slopes ................................................................. 265 690 4.2 0.01

158—Semiarid and Subhumid Low Mountain Slopes ....................................................... 520 1,340 8.3 0.01

159A—Humid and Very Humid Volcanic Ash Soils on Low and Intermediate Rolling

Mountain Slopes ............................................................................................................. 535 1,390 8.5 0.01

159B—Subhumid and Humid Low and Intermediate Mountain Slopes ........................... 245 640 3.9 0.01

160—Subhumid and Humid Intermediate and High Mountain Slopes ............................. 500 1,290 8.0 0.01

161A—Lava Flows and Rock Outcrops ........................................................................... 1,580 4,100 25.2 0.04

161B—Semiarid and Subhumid Organic Soils on Lava Flows .......................................... 385 1,000 6.1 0.01

162—Humid and Very Humid Organic Soils on Lava Flows ............................................. 550 1,430 8.8 0.02

163—Alluvial Fans and Coastal Plains .............................................................................. 140 365 2.2 0.00

164—Humid and Very Humid Steep and Very Steep Mountain Slopes ............................. 760 1,970 12.1 0.02

165—Subhumid Intermediate Mountain Slopes ................................................................ 110 290 1.8 0.00

166—Very Stony Land and Rock Land .............................................................................. 445 1,160 7.1 0.01

167—Humid Oxidic Soils on Low and Intermediate Rolling Mountain Slopes ............... 230 595 3.7 0.01

W1—Southern Alaska ........................................................................................................ 95,210 246,710 --- 2.65

220—Alexander Archipelago-Gulf of Alaska Coast ...................................................... 27,435 71,085 28.8 0.76

221—Kodiak Archipelago ............................................................................................... 5,015 12,995 5.3 0.14

222—Southern Alaska Coastal Mountains .................................................................... 26,335 68,235 27.7 0.73

223—Cook Inlet Mountains .......................................................................................... 19,700 51,050 20.7 0.55

224—Cook Inlet Lowlands ............................................................................................ 10,635 27,565 11.2 0.30

225—Southern Alaska Peninsula Mountains .................................................................. 6,090 15,780 6.4 0.17

W2—Aleutian Alaska

226—Aleutian Islands-Western Alaska Peninsula ......................................................... 10,670 27,645 100.0 0.30
662

Area and Proportionate Extent of the Land Resource Regions and Major Land Resource Areas—Cont.

 Extent in—

Land resource region and major land resource area Area United

LRR States

 mi2 km2 pct pct

X1—Interior Alaska .......................................................................................................... 259,260 671,835 --- 7.22

227—Copper River Basin ................................................................................................ 4,590 11,900 1.8 0.13

228—Interior Alaska Mountains .................................................................................... 44,375 114,985 17.1 1.24

229—Interior Alaska Lowlands ..................................................................................... 36,320 94,120 14.0 1.01

230—Yukon-Kuskokwim Highlands ............................................................................. 59,860 155,115 23.1 1.67

231—Interior Alaska Highlands..................................................................................... 69,175 179,255 26.7 1.93

232—Yukon Flats Lowlands .......................................................................................... 12,785 33,130 4.9 0.36

233—Upper Kobuk and Koyukuk Hills and Valleys ..................................................... 12,910 33,455 5.0 0.36

234—Interior Brooks Range Mountains ....................................................................... 19,245 49,875 7.4 0.54

X2—Western Alaska ........................................................................................................... 91,300 236,585 --- 2.54

235—Northern Alaska Peninsula Mountains .................................................................. 5,715 14,815 6.3 0.16

236—Bristol Bay-Northern Alaska Peninsula Lowlands .............................................. 19,575 50,725 21.4 0.54

237—Ahklun Mountains ............................................................................................... 14,555 37,715 15.9 0.41

238—Yukon-Kuskokwim Coastal Plain ........................................................................ 29,960 77,640 32.8 0.83

239—Northern Bering Sea Islands ................................................................................... 3,575 9,260 3.9 0.10

240—Nulato Hills-Southern Seward Peninsula Highlands ........................................... 17,920 46,430 19.6 0.50

Y—Northern Alaska ......................................................................................................... 125,550 325,345 --- 3.49

241—Seward Peninsula Highlands ................................................................................ 13,455 34,870 10.7 0.37

242—Northern Seward Peninsula-Selawik Lowlands ..................................................... 8,165 21,155 6.5 0.23

243—Western Brooks Range Mountains, Foothills, and Valleys.................................. 23,070 59,780 18.4 0.64

244—Northern Brooks Range Mountains ..................................................................... 15,695 40,675 12.5 0.44

245—Arctic Foothills .................................................................................................... 42,305 109,625 33.7 1.18

246—Arctic Coastal Plain .............................................................................................. 22,860 59,240 18.2 0.64

Z—Caribbean Region .......................................................................................................... 3,595 9,310 --- ---

270—Humid Mountains and Valleys ............................................................................... 1,800 4,660 50.1 ---

271—Semiarid Mountains and Valleys .............................................................................. 525 1,365 14.6 ---

272—Humid Coastal Plains ................................................................................................ 965 2,500 26.8 ---

273—Semiarid Coastal Plains ............................................................................................. 305 785 8.5 ---

United States Total ......................................................................................... 3,592,265 9,308,715 --- 100.00
663

Appendix III.—Water Use

Comparison of Surface and Ground Water Use in the U.S. and the Caribbean in 1980, 1990, and 2000

 Fresh surface water use Fresh ground water use

(millions of gallons per day) (millions of gallons per day)

State Year Total Percent Total Percent

difference difference

from 1990 from 1990

Alabama 2000 9,550 23 439 2

1990 7,747 431

1980 10,641 37 347 -20

Alaska 2000 111 -63 50 -21

1990 302 63

1980 224 -26 49 -23

Arizona 2000 3,304 -14 3,423 25

1990 3,833 2,745

1980 7,953 107 4,222 54

Arkansas 2000 3,949 26 6,928 47

1990 3,129 4,712

1980 15,688 401 4,012 -15

California 2000 23,213 13 15,204 4

1990 20,563 14,577

1980 43,797 113 21,376 47

Colorado 2000 10,324 4 2,320 -16

1990 9,913 2,774

1980 15,698 58 2,819 2

Connecticut 2000 564 -37 143 -14

1990 901 166

1980 1,316 46 136 -18

Delaware 2000 466 -50 115 29

1990 939 89

1980 139 -85 82 -9

District of Columbia 2000 10 -88 0 -100

1990 80 1

1980 341 327 1 -20

Florida 2000 3,110 9 5,023 8

1990 2,864 4,662

1980 7,389 158 3,799 -19

Georgia 2000 4,960 16 1,446 45

1990 4,290 997

1980 6,698 56 1,171 17
664

Comparison of Surface and Ground Water Use in the U.S. and the Caribbean in 1980, 1990, and 2000—Cont.

 Fresh surface water use Fresh ground water use

(millions of gallons per day) (millions of gallons per day)

State Year Total Percent Total Percent

difference difference

from 1990 from 1990

Hawaii 2000 208 -65 433 -26

1990 601 588

1980 1,304 117 788 34

Idaho 2000 15,272 26 4,139 -45

1990 12,162 7,594

1980 18,433 52 6,409 -16

Illinois 2000 12,973 -24 813 -19

1990 17,115 1,002

1980 17,857 4 926 -8

Indiana 2000 9,464 8 656 6

1990 8,800 622

1980 13,772 57 1,289 107

Iowa 2000 2,680 10 679 37

1990 2,440 494

1980 4,301 76 758 54

Kansas 2000 2,822 64 3,790 -13

1990 1,722 4,368

1980 6,564 281 5,619 29

Kentucky 2000 3,963 -3 190 -23

1990 4,072 248

1980 4,875 20 248 0

Louisiana 2000 8,734 10 1,627 21

1990 7,946 1,339

1980 12,282 55 1,762 32

Maine 2000 423 -5 81 -6

1990 447 86

1980 840 88 81 -6

Maryland 2000 1,202 -2 225 -6

1990 1,229 239

1980 1,130 -8 154 -36

Massachusetts 2000 782 -55 270 -20

1990 1,735 338

1980 2,462 42 321 -5
665

Comparison of Surface and Ground Water Use in the U.S. and the Caribbean in 1980, 1990, and 2000—Cont.

 Fresh surface water use Fresh ground water use

(millions of gallons per day) (millions of gallons per day)

State Year Total Percent Total Percent

difference difference

from 1990 from 1990

Michigan 2000 9,269 -15 734 4

1990 10,918 703

1980 15,392 41 536 -24

Minnesota 2000 3,146 27 720 -10

1990 2,475 798

1980 3,078 24 670 -16

Mississippi 2000 631 -3 2,181 -18

1990 649 2,670

1980 2,868 342 1,504 -44

Missouri 2000 6,444 25 1,777 144

1990 5,142 728

1980 6,817 33 479 -34

Montana 2000 8,103 -11 188 -8

1990 9,093 205

1980 11,518 27 266 30

Nebraska 2000 4,386 6 7,858 62

1990 4,149 4,850

1980 11,993 189 7,141 47

Nevada 2000 2,048 -10 758 -29

1990 2,278 1,068

1980 3,587 57 709 -34

New Hampshire 2000 361 1 85 34

1990 356 64

1980 385 8 65 3

New Jersey 2000 1,585 -4 584 3

1990 1,653 566

1980 2,893 75 722 28

New Mexico 2000 1,710 -1 1,544 -12

1990 1,721 1,761

1980 3,934 129 1,849 5

New York 2000 6,184 -36 893 7

1990 9,641 838

1980 7,934 -18 788 -6
666

Comparison of Surface and Ground Water Use in the U.S. and the Caribbean in 1980, 1990, and 2000—Cont.

 Fresh surface water use Fresh ground water use

(millions of gallons per day) (millions of gallons per day)

State Year Total Percent Total Percent

difference difference

from 1990 from 1990

North Carolina 2000 9,149 8 580 33

1990 8,501 436

1980 8,079 -5 772 77

North Dakota 2000 1,017 -60 123 -26

1990 2,539 167

1980 1,308 -48 118 -29

Ohio 2000 10,274 -5 878 -3

1990 10,765 904

1980 13,534 26 977 8

Oklahoma 2000 989 30 771 17

1990 761 661

1980 1,713 125 956 45

Oregon 2000 5,941 -22 993 28

1990 7,664 777

1980 6,828 -11 1,133 46

Pennsylvania 2000 9,283 5 666 -35

1990 8,809 1,023

1980 15,471 76 1,023 0

Rhode Island 2000 109 2 29 14

1990 107 25

1980 175 63 38 50

South Carolina 2000 6,838 20 331 -7

1990 5,719 355

1980 6,151 8 230 -35

South Dakota 2000 306 -10 222 -25

1990 341 296

1980 697 104 329 11

Tennessee 2000 10,409 20 417 -17

1990 8,685 504

1980 10,107 16 446 -11

Texas 2000 16,324 28 8,461 15

1990 12,733 7,387

1980 14,320 12 8,038 9
667

Comparison of Surface and Ground Water Use in the U.S. and the Caribbean in 1980, 1990, and 2000—Cont.

 Fresh surface water use Fresh ground water use

(millions of gallons per day) (millions of gallons per day)

State Year Total Percent Total Percent

difference difference

from 1990 from 1990

Utah 2000 3,739 8 1,021 6

1990 3,474 963

1980 4,543 31 1,035 8

Vermont 2000 404 -32 43 -20

1990 595 54

1980 344 -42 45 -16

Virginia 2000 4,888 14 313 -30

1990 4,275 444

1980 5,576 30 392 -12

Washington 2000 3,799 -41 1,475 -1

1990 6,457 1,487

1980 8,259 28 754 -49

West Virginia 2000 5,058 31 91 -88

1990 3,868 728

1980 5,638 46 218 -70

Wisconsin 2000 6,785 16 813 20

1990 5,827 680

1980 5,752 -1 613 -10

Wyoming 2000 4,404 -39 541 21

1990 7,200 446

1980 5,397 -25 540 21

Puerto Rico 2000 483 15 137 -13

1990 419 158

1980 819 95 319 102

U.S. Virgin Islands 2000 11 45 1 -91

1990 7 11

1980 6 -15 4 -64

Totals 2000 262,163 1 83,226 4

1990 259,654 79,888

1980 378,821 46 89,078 12
668

Appendix IV.—Soil Classification

In this appendix, the basic structure of the soil classification

system used in the United States is described. This system has

six categories (Soil Survey Staff, 1999). Beginning with the

broadest, these categories are the order, suborder, great group,

subgroup, family, and series. Classification is based on soil

properties observed in the field or inferred from those

observations or from laboratory measurements. The categories

are defined in the following paragraphs.

ORDER. Twelve soil orders are recognized. The differences

among orders reflect the dominant soil-forming processes and

the degree of soil formation. Each order is identified by a word

ending in sol. An example is Alfisol. The orders are described in

the next part of this appendix.

SUBORDER. Each order is divided into suborders primarily

on the basis of properties that influence soil genesis and are

important to plant growth or properties that reflect the most

important variables within the orders. The last syllable in the

name of a suborder indicates the order. An example is Udalfs

(Ud, meaning humid, plus alf, from Alfisol).

GREAT GROUP. Each suborder is divided into great groups

on the basis of close similarities in kind, arrangement, and

degree of development of pedogenic horizons; soil moisture

and temperature regimes; type of saturation; and base status.

Each great group is identified by the name of a suborder and by

a prefix that indicates a property of the soil. An example is

Hapludalfs (Hapl, meaning minimal horizonation, plus udalf,

the suborder of the Alfisols that has a udic soil moisture

regime).

SUBGROUP. Each great group has a typic subgroup. Other

subgroups are intergrades or extragrades. The typic subgroup is

the central concept of the great group; it is not necessarily the

most extensive. Intergrades are transitions to other orders,

suborders, or great groups. Extragrades have some properties

that are not representative of the great group but do not

indicate transitions to any other taxonomic class. Each

subgroup is identified by one or more adjectives preceding the

name of the great group. The adjective Typic identifies the

subgroup that typifies the great group. An example is Typic

Hapludalfs.

FAMILY. Families are established within a subgroup on the

basis of physical and chemical properties and other

characteristics that affect management. Generally, the properties

are those of horizons below tillage depth where there is much

biological activity. Among the properties and characteristics

considered are particle-size class, mineralogy class, cationexchange activity class, soil temperature regime, soil depth,

and reaction class. A family name consists of the name of a

subgroup preceded by terms that indicate soil properties. An

example is fine-loamy, mixed, active, mesic Typic Hapludalfs.

SERIES. The series consists of soils within a family that

have horizons similar in color, texture, structure, reaction,

consistence, mineral and chemical composition, and

arrangement in the profile.

Description of Soil Orders

Alfisols are in semiarid to moist areas. These soils result from

weathering processes that leach clay minerals and other

constituents out of the surface layer and into the subsoil, where

they can hold and supply moisture and nutrients to plants. The

soils formed primarily under forest or mixed vegetative cover

and are productive for most crops.

Andisols form through weathering processes that generate

minerals with little orderly crystalline structure. These minerals

can result in an unusually high water- and nutrient-holding

capacity. As a group, Andisols tend to be highly productive

soils. They include weakly weathered soils with much volcanic

glass as well as more strongly weathered soils. They are

common in cool areas with moderate to high precipitation,

especially those areas associated with volcanic materials.

Aridisols are soils that are too dry for the growth of

mesophytic plants. The lack of moisture greatly restricts the

intensity of weathering processes and limits most soil

development processes to the upper part of the soils. Aridisols

commonly accumulate gypsum, salt, calcium carbonate, and

other minerals that are easily leached from soils in more humid

environments.

Entisols are soils that show little or no evidence of

pedogenic development. They occur in areas of recently

deposited parent materials or in areas where erosion or

deposition rates are faster than the rate of soil development,

such as dunes, steep slopes, and flood plains. The soils occur in

many environments.

Gelisols are soils that have permafrost near the soil surface

and/or have evidence of cryoturbation (frost churning) and/or

ice segregation. These soils are common in the higher latitudes

or at high elevations.

Histosols have a high content of organic matter and no

permafrost. Most are saturated throughout the year, but a few

are freely drained. Histosols are commonly called bogs, moors,

peats, or mucks. They form in decomposed plant remains that

accumulate in water, forest litter, or moss faster than they decay.

If these soils are drained and exposed to air, microbial

decomposition is accelerated and the soils may subside

dramatically.

Inceptisols are soils of semiarid to humid environments that

generally exhibit only moderate degrees of soil weathering and

development. These soils have a wide range in characteristics

and occur in a wide variety of climates.

Mollisols are soils that have a dark colored surface horizon

relatively high in content of organic matter. These soils are base

rich throughout and therefore are quite fertile. They

characteristically form under grass in climates that have a

moderate to pronounced seasonal moisture deficit, such as the

Great Plains and prairie regions.
669

Oxisols are highly weathered soils of tropical and

subtropical regions. They are dominated by low-activity

minerals, such as quartz, kaolinite, and iron oxides. They tend

to have indistinct horizons. These soils characteristically occur

on surfaces that have been stable for a long time. They have

low natural fertility as well as a low capacity to retain additions

of lime and fertilizer.

Spodosols formed through weathering processes that strip

organic matter combined with aluminum (with or without iron)

from the surface layer and deposit them in the subsoil. In

undisturbed areas, a gray eluvial horizon that has the color of

uncoated quartz overlies a reddish brown or black subsoil.

These soils commonly occur in areas of coarse textured

deposits under coniferous forests of humid regions. They tend

to be acid and infertile.

Ultisols are soils in humid areas. They formed through fairly

intense weathering and leaching processes that result in a clayenriched subsoil dominated by minerals, such as quartz,

kaolinite, and iron oxides. They are typically acid soils in

which most nutrients are concentrated in the upper few inches.

They have a moderately low capacity to retain additions of

lime and fertilizer.

Vertisols have a high content of expanding clay minerals.

They undergo pronounced changes in volume with changes in

moisture content. They have cracks that open and close

periodically and that show evidence of soil movement in the

profile. Because they swell when wet, these soils transmit water

very slowly and have undergone little leaching. They tend to

be fairly high in natural fertility.

Additional Information

Additional information about soil taxonomy, including indepth technical details about the classification system and

descriptions of each of the soil series referred to in this

publication, can be accessed online (http://soils.usda.gov/

technical/classification/).

Definitions of many of the terms describing parent material

and landforms are available in the National Soil Survey

Handbook (http://soils.usda.gov/technical/handbook/contents/

part629glossary1.html).

Detailed information about the soil surveys of specific areas

can be obtained from the appropriate NRCS State Soil Scientist

(http://soils.usda.gov/contact/state_offices/).
The Natural Resources Conservation Service (NRCS) is committed to making its

information accessible to all of its customers and employees. If you are experiencing

accessibility issues and need assistance, please contact our Helpdesk by phone at

1-800-457-3642 or by e-mail at ServiceDesk-FTC@ftc.usda.gov. For assistance with

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to contact our State or local office. You can locate the correct office and phone number at

http://offices.sc.egov.usda.gov/locator/app.

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