Ozark-Ouachita

Highlands Assessment

Aquatic Conditions

REPORT

3

OF 5

United States

Department of

Agriculture

Forest Service

Southern

Research Station

General Technical

Report SRS-33
Cover photo: Twin Falls, Richland Creek, Ozark Plateaus

Photo by A.C. Haralson, Arkansas Department of Parks and Recreation, Little Rock, AR.

Natural resource specialists and research scientists worked together to produce the five General

Technical Reports that comprise the Ozark-Ouachita Highlands Assessment:

• Summary Report

• Air Quality

• Aquatic Conditions

• Social and Economic Conditions

• Terrestrial Vegetation and Wildlife

For information regarding how to obtain these Assessment documents, please contact: USDA Forest

Service, P.O. Box 1270, Hot Springs, AR 71902 or telephone 501-321-5202.

To limit publication costs, few color maps and figures were used in the Assessment reports. For color

versions of some of the Assessment figures and supplemental material, please see the Assessment’s home

page on the Internet at <http://www.fs.fed.us/oonf/ooha/welcome.htm>. The Assessment reports will

be online for about 2 years after the date on this publication; then they will be archived.

Please note: When “authors” are agency or business names, most are abbreviated to save space in the

citations of the body of the report. The “References” at the end of the report contain both the full name

and abbreviations. Because abbreviations sometimes are not in the same alphabetical order as the references, for clarifications of abbreviations, consult the “Glossary of Abbreviations and Acronyms.”

The use of trade, firm, or corporation names in this publication is for the information and convenience of

the readers. Such use does not constitute an official endorsement of any product or service by the USDA

Forest Service.

December 1999

Southern Research Station

P.O. Box 2680

Asheville, North Carolina 28802
Ozark-Ouachita Highlands Assessment:

Aquatic Conditions

Eastern Region

U. S. Department of Agriculture

Forest Service

Milwaukee, WI

North Central Research Station

U.S. Department of Agriculture

Forest Service

St. Paul, MN

Southern Region

U. S. Department of Agriculture

Forest Service

Atlanta, GA

Southern Research Station

U.S. Department of Agriculture

Forest Service

Asheville, NC

Contents

Page

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v

Contributors to This Report. . . . . . . . . . . . . . . . . . vi

Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . . . . xi

Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . xiii

Chapter 1: Introduction to the

Aquatic Study Area . . . . . . . . . . . . . 1

Physiography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Ozark Plateaus Province . . . . . . . . . . . . . . . . . . . 1

Ouachita Province . . . . . . . . . . . . . . . . . . . . . . . . 3

Central Lowland and Coastal Plains

Provinces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Major River Basins . . . . . . . . . . . . . . . . . . . . . . . . . 4

Ozark Plateaus Province . . . . . . . . . . . . . . . . . . . 7

Ouachita Province . . . . . . . . . . . . . . . . . . . . . . . 15

Major Lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Ground Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Ground Water in the Ozark Plateaus

Province. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Ground Water in the Ouachita Province . . . . . . 24

Climate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Monthly Average Maximum Temperature

Patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Monthly Average Minimum Temperature

Patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Extreme Maximum Temperature

Occurrences . . . . . . . . . . . . . . . . . . . . . . . . . 29

Extreme Minimum Temperature

Occurrences . . . . . . . . . . . . . . . . . . . . . . . . . 30

Average Monthly Precipitation Patterns . . . . . . 32

Extreme Precipitation Occurrences . . . . . . . . . 34

Droughts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Tornadoes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Runoff . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Geology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Geologic Setting of the Ozark Plateaus

Province. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Page

Structural Geology of the Ozark Plateaus . . . . 47

Geological History of the Ozark Plateaus. . . . . 47

Geologic Setting of the Ouachita Province . . . . 48

Structural Geology of the Ouachita

Province. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Geological History of the Ouachita

Province. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Ozark Plateaus Province Soils . . . . . . . . . . . . . 50

Ouachita Province Soils . . . . . . . . . . . . . . . . . . 51

Changing Land Conditions . . . . . . . . . . . . . . . . . . . 52

Chapter 2: Status of Aquatic

Resources . . . . . . . . . . . . . . . . . . . . . . 55

Water Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Surface Water Quality (Streams) . . . . . . . . . . . 55

Surface Water Quality (Lakes) . . . . . . . . . . . . . 86

Ground Water Quality . . . . . . . . . . . . . . . . . . . . 91

Aquatic Animals and Their Habitats . . . . . . . . . . 100

Diversity of Fishes . . . . . . . . . . . . . . . . . . . . . . 100

Diversity of Mussels . . . . . . . . . . . . . . . . . . . . 115

Diversity of Crayfishes . . . . . . . . . . . . . . . . . . 132

Diversity of Aquatic Insects . . . . . . . . . . . . . . 140

Endangered, Threatened, and Other

Aquatic Species of Special Concern . . . . . 153

Commercially and Recreationally

Important Species . . . . . . . . . . . . . . . . . . . . 162

Management Indicator Species . . . . . . . . . . . . 171

Aquatic Habitats . . . . . . . . . . . . . . . . . . . . . . . 176

Riparian Areas. . . . . . . . . . . . . . . . . . . . . . . . . 181

Wetlands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184

Chapter 3: The Clean Water Act and

Aquatic Restoration Programs. . . 191

The Clean Water Act (CWA) . . . . . . . . . . . . . . . 191

Clean Water Act (CWA) Sections . . . . . . . . . 193

Wetlands—Section 404 . . . . . . . . . . . . . . . . . . 194

National Pollutant Discharge Elimination

System (NPDES) . . . . . . . . . . . . . . . . . . . . 195

iii
Page

Total Maximum Daily Loads (TMDL’s),

Section 303(d) . . . . . . . . . . . . . . . . . . . . . . . 196

Antidegradation Policy . . . . . . . . . . . . . . . . . . 197

Nonpoint Source Pollution Control . . . . . . . . . 197

Section 319 . . . . . . . . . . . . . . . . . . . . . . . . . . . 197

Aquatic Restoration Programs . . . . . . . . . . . . . . 199

Bring Back the Natives . . . . . . . . . . . . . . . . . . 199

Challenge 21 . . . . . . . . . . . . . . . . . . . . . . . . . . 199

Clean Water Action Plan . . . . . . . . . . . . . . . . 199

Conservation Reserve Program (CRP) . . . . . 199

Conservation Technical Assistance (CTA)

Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200

Emergency Watershed Protection (EWP)

Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200

Environmental Quality Incentives Program

(EQIP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200

Fisheries Across America . . . . . . . . . . . . . . . . 200

Forestry Incentives Program (FIP). . . . . . . . . 200

Partners for Wildlife . . . . . . . . . . . . . . . . . . . . 200

Rivers, Trails, and Conservation Assistance

Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201

Section 319 Nonpoint Source Program . . . . . . 201

Section 1135 Program . . . . . . . . . . . . . . . . . . . 201

Small Watershed Program and Flood

Prevention Program . . . . . . . . . . . . . . . . . . 201

State and Private Forestry, Cooperative

Forestry . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201

Stewardship Incentives Program (SIP) . . . . . 201

Watershed and River Basin Planning and

Installation (Public Law 566) . . . . . . . . . . . 202

Wetlands Reserve Program (WRP) . . . . . . . . 202

Chapter 4: Effects of Human

Activities . . . . . . . . . . . . . . . . . . . . . . 203

State and Federal Classifications of Water

Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203

Outstanding Resource Waters (ORW’s) . . . . 203

Page

Impaired Waters . . . . . . . . . . . . . . . . . . . . . . . 204

EPA Index of Watershed Indicators (IWI) . . 209

Point Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

CERCLA and Superfund Sites . . . . . . . . . . . . 212

National Pollutant Discharge Elimination

System (NPDES) Sites . . . . . . . . . . . . . . . . 215

Municipal Water Supplies . . . . . . . . . . . . . . . . 219

Toxic Releases. . . . . . . . . . . . . . . . . . . . . . . . . 222

Nonpoint Sources . . . . . . . . . . . . . . . . . . . . . . . . . 226

Roads and Highways. . . . . . . . . . . . . . . . . . . . 226

Agriculture and Silviculture . . . . . . . . . . . . . . . 229

Pesticides—Applications and Distributions . . 236

Pesticides in Surface Water . . . . . . . . . . . . . . 239

Pesticides in Ground Water . . . . . . . . . . . . . . . 249

Animal Wastes. . . . . . . . . . . . . . . . . . . . . . . . . 253

Fertilizers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255

Urbanization . . . . . . . . . . . . . . . . . . . . . . . . . . . 257

Mineral Extraction . . . . . . . . . . . . . . . . . . . . . . 260

Introduced Species . . . . . . . . . . . . . . . . . . . . . 264

Chapter 5: Water Supply and Use . . . . . . . . . . 269

Past and Present Supply and Use . . . . . . . . . . . . 269

Comparisons of Water Supply and Use . . . . . 269

Future Patterns and Trends . . . . . . . . . . . . . . . . . 275

Withdrawals . . . . . . . . . . . . . . . . . . . . . . . . . . . 276

References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279

Glossary of Terms . . . . . . . . . . . . . . . . . . . . . . . . 299

Glossary of Abbreviations and

Acronyms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309

List of Tables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311

List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314

iv
Preface

Change is evident across the Ozark and Ouachita Highlands. Whether paying attention to State and

regional news, studying statistical patterns and trends, or driving through the Highlands, one cannot escape

signs that growth may be putting strains on the area’s natural resources and human communities. How

people regard these changes varies widely, however, as does access to reliable information that might help

them assess the significance of what is happening in the Highlands. The Assessment reports provide

windows to a wealth of such information.

The Aquatic Conditions report is one of five that document the results of the Ozark-Ouachita Highlands Assessment. Federal and State natural resource agency employees and university and other cooperators worked together to produce the four technical reports that examine air quality; aquatic conditions;

terrestrial vegetation and wildlife; and social and economic conditions. Dozens of experts in various fields

provided technical reviews. Other citizens were involved in working meetings and supplied valuable ideas

and information. The Summary Report provides an overview of the key findings presented in the four

technical reports. Data sources, methods of analysis, findings, discussion of implications, and links to

dozens of additional sources of information are discussed in more detail in the four technical reports.

The USDA Forest Service initiated the Assessment and worked with other agencies to develop a

synthesis of the best information available on conditions and trends in the Ozark-Ouachita Highlands.

Assessment reports emphasize those conditions and trends most likely to have some bearing on the future

management of the region’s three national forests—the Mark Twain, Ouachita, and Ozark-St. Francis.

People who are interested in the future of the region’s other public lands and waters, or of this remarkable

region as a whole, should also find the reports valuable.

No specific statutory requirement led to the Assessment. However, data and findings assembled in the

reports will provide some of the information relevant for an evaluation of possible changes in the land and

resource management plans of the Highland’s three national forests. The National Forest Management

Act directs the Forest Service to revise such management plans every 10 to 15 years, which means that

the national forests of Arkansas, Missouri, and Oklahoma should have revised plans in the year 2001. Due

to restrictions in the appropriations bill that provides funding for the Forest Service, it is uncertain when

these revisions can begin.

The charter for the Ozark-Ouachita Highlands Assessment established a team structure and listed

tentative questions that the teams would address. Assembled in mid-1996, the Terrestrial, Aquatic and

Atmospheric, and Human Dimensions (Social-Economic) Teams soon refined and condensed these

questions and then gathered and evaluated vast quantities of information. They drafted their key findings in

late 1997 and refined them several times through mid-1999. In addition to offering relevant data and key

findings in the reports, the authors discuss some of the possible implications of their findings for future

public land management in the Highlands and for related research. The Assessment reports, however, stop

well short of making decisions concerning management of any lands in the Highlands or about future

research. In no way do the reports represent “plans” or land management decisions. Instead, the findings

and conclusions offered in the Assessment reports are intended to stimulate discussion and further study.

v
Contributors to This Report

Assessment Team Leader

William F. Pell, Ecologist, USDA Forest Service, Hot Springs, AR

Aquatic-Atmospheric Team Leader

J. Alan Clingenpeel, Forest Hydrologist, USDA Forest Service, Ouachita National Forest, Hot Springs, AR

Authors

Chapter 1: Introduction to the Aquatic Study Area

Physiography: Phillip D. Hays

Major River Basins: Richard W. Bell

Major Lakes: Richard W. Standage

Ground Water: Phillip D. Hays

Climate: Warren E. Heilman

Runoff: Richard W. Bell

Geology: Phillip D. Hays, David A. Freiwald

Soils: Len Weeks

Changing Land Conditions : Phillip D. Hays

Chapter 2: Status of Aquatic Resources

Surface Water Quality (Streams): Richard W. Bell

Surface Water Quality (Lakes): Richard W. Standage

Ground Water Quality: Phillip D. Hays, David A. Freiwald

Diversity of Fishes: Melvin L. Warren, Jr., Lisa Hlass

Diversity of Mussels: John L. Harris

Diversity of Crayfishes: Melvin L. Warren, Jr., Henry W. Robison, Karen Tinkle

Diversity of Aquatic Insects: Betty G. Crump, Melvin L. Warren, Jr.

Endangered, Threatened, and Other Aquatic Species of Special Concern: Melvin L. Warren, Jr.,

Karen Tinkle

Commercially and Recreationally Important Species: Richard W. Standage

Management Indicator Species: Richard W. Standage

Aquatic Habitats: Melvin L. Warren, Jr., J. Alan Clingenpeel

Riparian Areas: J. Alan Clingenpeel

Wetlands: Len Weeks

vi
Chapter 3: The Clean Water Act and Aquatic Restoration Programs

Jack Hill

Chapter 4: Effects of Human Activities

Outstanding Resource Waters: J. Alan Clingenpeel

Impaired Waters: J. Alan Clingenpeel

EPA Index of Watershed Indicators: J. Alan Clingenpeel

CERCLA and Superfund Sites: Jack Hill

National Pollutant Discharge Elimination System (NPDES) Sites: Jack Hill

Municipal Water Supplies: Jack Hill

Toxic Releases: Jack Hill

Roads and Highways: Len Weeks

Agriculture and Silviculture: Len Weeks

Pesticides—Applications and Distributions: Richard W. Bell, Phillip D. Hays

Pesticides in Surface Water: Richard W. Bell

Pesticides in Ground Water: Phillip D. Hays

Animal Wastes: Richard W. Bell

Fertilizers: Richard W. Bell

Urbanization: J. Alan Clingenpeel

Mineral Extraction: John C. Nichols

Introduced Species: Richard W. Standage

Chapter 5: Water Supply and Use

Past and Present Supply and Use: Thomas C. Brown and Terry W. Holland

Future Patterns and Trends: Thomas C. Brown

Author Information

Richard W. Bell, Hydrologist, USDI Geological Survey, Water Resources Division, Little Rock, AR.

Thomas C. Brown, Economist, USDA Forest Service, Rocky Mountain Research Station,

Fort Collins, CO.

J. Alan Clingenpeel, Forest Hydrologist, USDA Forest Service, Ouachita National Forest,

Hot Springs, AR.

Betty G. Crump, Aquatic Ecologist, USDA Forest Service, Ouachita National Forest, Glenwood, AR.

David A. Freiwald, Supervisory Hydrologist, USDI Geological Survey, Water Resources Division, Little

Rock, AR.

John L. Harris, Section Head-Special Studies, Arkansas Department of Highways and Transportation,

Little Rock, AR, and Consulting Malacologist.

Phillip D. Hays, Hydrologist, USDI Geological Survey, Water Resources Division, Little Rock, AR.

Warren E. Heilman, Research Meteorologist, USDA Forest Service, North Central Research Station, East

Lansing, MI.

Jack Hill, Forest Service–U.S. Environmental Protection Agency Liaison, USDA Forest Service,

Dallas, TX.

vii
Lisa Hlass, Biologist, USDA Forest Service, Ouachita National Forest, Mt. Ida, AR.

Terry W. Holland, Hydrologic Technician, USDI Geological Survey, Water Resources Division, Little

Rock, AR.

John C. Nichols, Forest Minerals Geologist, USDA Forest Service, Ouachita National Forest, Hot Springs,

AR.

Henry W. Robison, Professor of Biology, Southern Arkansas University, Department of Biology, Magnolia,

AR.

Richard W. Standage, Forest Fisheries and Aquatic Threatened and Endangered Species Biologist, USDA

Forest Service, Ouachita National Forest, Hot Springs, AR.

Karen Tinkle, Biologist, USDA Forest Service, Ozark National Forest, Mountain View, AR.

Melvin L. Warren, Jr., Research Fisheries Biologist, USDA Forest Service, Southern Research Station,

Oxford, MS.

Len Weeks, Soil Scientist, USDA Forest Service, Ozark National Forest, Russellville, AR.

Other Contributors

James C. Adamski, Hydrologist, USDI Geological Survey, Little Rock, AR—data analysis.

Michael Armstrong, Assistant Fisheries Chief, Arkansas Game & Fish Commission, Little Rock, AR—

background on commercial fish and mussel harvest in Arkansas and Sate fisheries management

practices.

Steven W. Bearden, Cartographic Technician, USDI Geological Survey, Little Rock, AR—figures.

Chris Bennett, Geographic Information System (GIS) System Administrator, University of Arkansas,

School of Forest Resources, Monticello, AR—GIS data bases.

Amy J. Benson, Fishery Biologist, USDI Geological Survey, Biological Resources Division, Gainesville,

FL—nonindigenous aquatic vertebrate and nonvertebrate data for the Arkansas, Missouri, and Oklahoma species account reports.

Patti Bryant, Little Rock, AR—assistance with unionacean bivalve data base construction and analysis.

Al Buchanan, Fisheries Research Biologist, Missouri Department of Conservation, Jefferson City, MO—

data interpretation and legal background on mussel harvests.

Tim Burnley, District Fisheries Biologist, Arkansas Game & Fish Commission, Brinkley, AR—recent

commercial mussel harvest information and reports.

Dorothy Butler, Heritage Coordinator, Missouri Department of Conservation, Jefferson City, MO—

heritage data information.

Ian Butler, Data Coordinator, Oklahoma Biological Survey, Norman, OK—heritage data information.

Steve Downing, Commercial Shell Buyer, Locust Grove, OK—background information on commercial

harvest of mussels in Oklahoma.

Jeff Farwick, Regional Fisheries Biologist, Arkansas Game & Fish Commission, Brinkley, AR—commercial fish harvest and mussel harvest data and background information.

Larry Furniss, Forest Fisheries Biologist, USDA Forest Service, Mark Twain National Forest, Rolla,

MO—assistance in gathering Missouri Department of Conservation publications for fish species legal

status and stocking locations.

Anne Garner, Fisheries Secretary, Arkansas Game & Fish Commission, Hot Springs, AR—fish stocking

records to fill data gaps.

Mike Gibson, Assistant Fisheries Chief, Hatcheries, Arkansas Game & Fish Commission, Little Rock,

AR—fish stocking records of selected game fish species.

Jack Harper, Southeastern Region Fish Supervisor, Oklahoma Department of Wildlife Conservation,

Caddo, OK—fish stocking records and management details for waters in southeastern Oklahoma.

viii
Michael Hobbins, Civil Engineering student, Colorado State University, Fort Collins, CO—performing the

model runs to estimate available water supply.

Colette Jacono, Botanist, USDI Geological Survey, Biological Resources Division, Gainesville, FL —nonindigenous aquatic plant data for Arkansas, Missouri, and Oklahoma species account reports.

Robert Limbird, Regional Fisheries Biologist, Arkansas Game & Fish Commission, Russellville, AR—

commercial fish harvest data from Nimrod and Blue Mountain reservoirs and background information.

Charles M. Mather, Professor of Biology, University of Science and Arts of Oklahoma, Chickasha, OK—

distributional data and unpublished reports regarding Oklahoma unionaceans.

Dave Mayers, District Fisheries Management Biologist, Missouri Department of Conservation, West

Plains, MO—assistance with fish species legal status and fish stocking data.

Brian Obermeyer, Private Consultant, Stream and Prairie Research, Emporia, KS—distributional data and

unpublished reports regarding Oklahoma unionaceans.

Mark Oliver, Regional Fisheries Biologist, Arkansas Game & Fish Commission, Mountain Home, AR—

information on lake trout stocking and harvest in Greers Ferry Lake and other stocking practices in the

Ozarks.

Cindy Osborne, Data Manager, Arkansas Natural Heritage Commission, Little Rock, AR—heritage data

information.

Howard Perlman, Hydrologist, USDI Geological Survey, Atlanta, GA—assistance in accessing the water

use data.

James C. Petersen, Hydrologist, USDI Geological Survey, Little Rock, AR—text and data review.

John W. Robinson, Fisheries Research Biologist, Missouri Department of Conservation, Jefferson City,

MO—mussel and commercial fish species data and interpretation assistance.

Jim Smith, Northeast Region Fish Supervisor, Oklahoma Department of Wildlife Conservation, Porter,

OK—fish stocking records and management details for waters in northeastern Oklahoma, assistance

with fish species legal status, and background information on Oklahoma mussel harvest.

Wayne B. Solley, Chief of Water-Use Information Branch, USDI Geological Survey, Reston, VA—

assistance in accessing the water use data.

Peter Trenchi, Natural Resource Research Specialist, USDA Forest Service, Ouachita National Forest,

Hot Springs, AR—GIS data management.

Caryn Vaughn, Coordinator and Aquatic Zoologist, Oklahoma Biological Survey, Norman, OK—distributional data and unpublished reports regarding Oklahoma unionaceans.

Jeremy S. Vestal, Hydrology Co-op, USDA Forest Service, Ouachita National Forest, Hot Springs, AR—

final figure and glossary refinement.

Charles Wallace, Fisheries Division Administrative Assistant, Oklahoma Department of Wildlife Conservation, Oklahoma City, OK—provided commercial aquatic species harvest records and reports and

interpreted this material.

Robert Weih, Associate Professor, University of Arkansas, School of Forest Resources, Monticello, AR—

GIS data bases.

Stuart Wooldridge, Regional Fisheries Biologist, Arkansas Game & Fish Commission, Hot Springs, AR—

background information on fisheries management in the Ouachitas.

Brenda Wulff, Clerk-Typist, Missouri Department of Conservation, Sweet Springs, MO—compiled

requested fish stocking records.

Ozark-Ouachita Highlands Assessment Steering Team

G. Samuel Foster, Assistant Station Director of Research Programs–West, USDA Forest Service,

Southern Research Station, Asheville, NC.

ix
Randy Moore, Forest Supervisor, USDA Forest Service, Mark Twain National Forest, Rolla, MO.

Lynn C. Neff, Forest Supervisor, USDA Forest Service, Ozark-St. Francis National Forests,

Russellville, AR.

Alan G. Newman, Forest Supervisor, USDA Forest Service, Ouachita National Forest, Hot Springs, AR.

Editorial Team

Donna M. Paananen, Technical Writer-Editor, USDA Forest Service, North Central Research Station,

East Lansing, MI.

Ariana Mikulski, Editorial Assistant, USDA Forest Service, North Central Research Station,

East Lansing, MI.

Camilla M. Romund, Research Specialist, University of Arkansas, Fayetteville, AR.

Zachariah M. DeYoung, Editorial Assistant, USDA Forest Service, North Central Research Station,

East Lansing, MI.

Bobbie L. Louthian, Writer-Editor, USDI Geological Survey, Little Rock, AR.

Louise A. Wilde, Production Editor, USDA Forest Service, Southern Research Station, Asheville, NC.

x
Acknowledgments

The Aquatic Team would like to thank members of the public who attended meetings and/or provided

written or oral input during the Assessment process. The team also wishes to thank the aforementioned

organizations and individuals who contributed information used to write this report.

In addition, the Aquatic Team appreciates the help of the many individuals who reviewed various

sections of this general technical report. Their comments and suggestions contributed to the preparation of

this final document; information about them follows.

Reviewers

Michael Armstrong, Assistant Fisheries Chief, Arkansas Game & Fish Commission, Little Rock, AR—

“Commercially and Recreationally Important Species,” and “Management Indicator Species” sections

of Chapter 2 and “Introduced Species” section of Chapter 4.

Angela Braden, Geologist, Arkansas Geological Commission, Little Rock, AR—“Geology” section of

Chapter 1.

Ken Brazil, Engineer Supervisor of Planning Section, Arkansas Soil and Water Commission, Little Rock,

AR—Chapters 4 and 5.

Jim Brown, Geologist, Missouri Department of Natural Resources, Rolla, MO—“Geology” section of

Chapter 1.

Sue A. Bruenderman, Fisheries Research Biologist, Missouri Department of Conservation, Columbia,

MO—“Diversity of Mussels” section of Chapter 2.

Linda Chapman, Environmental Scientist, State Watershed Liaison, U.S. Environmental Protection

Agency, Region 6, Dallas, TX—Chapter 4.

George E. Dissmeyer, Hydrologist, Eatonton, GA—Chapters 2 and 3.

Robert J. DiStefano, Fisheries Research Biologist, Missouri Department of Conservation, Columbia,

MO—Chapter 2.

John Ford, Environmental Specialist, Missouri Department of Natural Resources, Jefferson City, MO—

Chapter 4.

Larry Furniss, Forest Fisheries Biologist, USDA Forest Service, Mark Twain National Forest, Columbia,

MO—“Commercially and Recreationally Important Species” and “Management Indicator Species”

sections of Chapter 2 and “Introduced Species” section of Chapter 4.

John Giese, Environmental Preservation Division Chief, Arkansas Department of Pollution Control and

Ecology, Little Rock, AR—Chapters 2 and 4.

George Harp, Professor of Environmental Biology, Arkansas State University, State University, AR—

Chapter 2.

Larry Hedrick, Integrated Resources Team Leader, USDA Forest Service, Ouachita National Forest, Hot

Springs, AR—original technical review of rough draft of “Commercially and Recreationally Important

Species” and “Management Indicator Species” in Chapter 2 and “Introduced Species” in Chapter 4.

Jack Holcomb, Hydrologist, USDA Forest Service, Southern Region, Atlanta, GA—Chapter 3.

J. Michael Howard, Geological Supervisor, Arkansas Geological Commission, Little Rock, AR—“Geology” section of Chapter 1.

Bill Keith, Chief, Planning Section, Arkansas Department of Pollution Control and Ecology, Little Rock,

AR—Chapters 1, 2, and 4.

Jim Leach, Assistant Director, Water Quality Program, Oklahoma Conservation Commission, Oklahoma

City, OK—Chapters 2 and 4.

xi
Bob Legler, Ozark Fisheries Region Supervisor, Missouri Department of Conservation, West Plains, MO—

“Commercially and Recreationally Important Species” and “Management Indicator Species” sections

of Chapter 2 and “Introduced Species” section of Chapter 4.

Dave Mayers, Fisheries Management Biologist, Missouri Department of Conservation, West Plains,

MO—“Commercially and Recreationally Important Species” and “Management Indicator Species”

sections of Chapter 2 and “Introduced Species” section of Chapter 4.

Steve McIntosh, Director, Water Resources Program, Missouri Department of Natural Resources,

Jefferson City, MO—Chapter 5.

Mark Middendorf, Geologist, Missouri Department of Natural Resources, Rolla, MO—“Geology” section

of Chapter 1.

Stephen R. Moulton, II, Biologist, Benthic Invertebrate Taxonomist, USDI Geological Survey, Water

Resource Division, Aquatic Invertebrate Section, Arvada, CO—“Diversity of Aquatic Insects” section

of Chapter 2.

James C. Petersen, Hydrologist, USDI Geological Survey, Little Rock, AR—Chapter 2.

Jimmie Pigg, Aquatic Biologist, Oklahoma Department of Environmental Quality, Oklahoma City, OK—

“Diversity of Fishes” section of Chapter 2.

Barry C. Poulton, Research Ecologist, Aquatic Entomologist, USDI Geological Survey, Biological

Resources Division, Columbia, MO—“Diversity of Aquatic Insects” section of Chapter 2.

W. L. Prior, Geologist, Arkansas Geological Commission, Little Rock, AR—“Geology” section of

Chapter 1.

John W. Robinson, Fisheries Research Biologist, Missouri Department of Conservation, Columbia, MO—

“Commercially and Recreationally Important Species” and “Management Indicator Species” sections

of Chapter 2 and “Introduced Species” section of Chapter 4.

Henry W. Robison, Professor of Biology, Southern Arkansas University, Magnolia, AR—“Diversity of

Fishes”; and “Endangered, Threatened, and Other Aquatic Species of Special Concern” sections of

Chapter 2.

Ardel Rueff, Geologist, Missouri Department of Natural Resources, Rolla, MO—“Geology” section of

Chapter 1.

Cheryl Seeger, Geologist, Missouri Department of Natural Resources, Rolla, MO—“Geology” section of

Chapter 1.

Jim Smith, Northeast Regional Fish Supervisor, Oklahoma Department of Wildlife Conservation, Porter,

OK—“Commercially and Recreationally Important Species” and “Management Indicator Species”

sections of Chapter 2 and “Introduced Species” section of Chapter 4.

Derek Smithee, Chief, Water Quality Programs Division, Oklahoma Water Resources Board, Oklahoma

City, OK—Chapters 4 and 5.

Charles E. Stone, Geological Supervisor, Arkansas Geological Commission, Little Rock, AR—“Geology”

section of Chapter 1.

Neil Suneson, Geologist, Oklahoma Geological Survey, Norman, OK—“Geology” section of Chapter 1.

Don Turton, Associate Professor of Forest Hydrology, Oklahoma State University, Stillwater, OK—

Chapters 1 and 2.

Jim Vandike, Hydrologist, Missouri Department of Natural Resources, Rolla, MO—“Geology” section of

Chapter 1.

Caryn Vaughn, Coordinator and Aquatic Zoologist, Oklahoma Biological Survey, Norman, OK—“Diversity

of Mussels” section of Chapter 2.

Dave Womack, Land Resource Specialist, Arkansas Soil and Water Commission, Little Rock, AR—

Chapters 4 and 5.

xii
Executive Summary

The Ozark-Ouachita Highlands Assessment was

designed as an interagency effort led by the USDA

Forest Service to collect and analyze ecological, social,

and economic data concerning the Highlands of Arkansas, Missouri, and Oklahoma. The aquatic portion of this

Assessment began in May of 1996 and was completed in

December of 1998. The information compiled will

facilitate an ecosystem approach to management of the

natural resources on public lands within the Ozark

Highlands, the Boston Mountains, the Arkansas Valley,

and the Ouachita Mountains. The Aquatic Team studied

conditions of the aquatic resources in these and surrounding areas.

The Aquatic Team, with input from scientists, forest

planners, and concerned citizens, identified 33 questions

that needed to be addressed in order to understand

aquatic conditions and trends in the Ozark-Ouachita

Highlands. Following is a summary of the team’s findings.

Chapter 1: Introduction to the Aquatic Study Area

The introductory chapter describes the physiography,

river basins, watersheds, major lakes, ground water,

climate, geology, soils, and land uses of the aquatic study

area and the slightly smaller Highlands Assessment area.

The Aquatic Team used physiographic areas, river basins,

and watersheds as the principal geographic units for

displaying data throughout most of the report. An understanding of physiographic areas, river basins, watersheds,

and the other background information in this chapter

provides the reader with a context for the chapters that

follow.

Chapter 2: Status of Aquatic Resources

Chapter 2 examines two broad categories of the aquatic

ecosystem in the Highlands. “Water Quality” includes

information about the chemical characteristics of streams,

lakes, and ground water. “Aquatic Animals and their

Habitats,” the second major section, discusses the biological components of water, including the status of fish,

mussels, crayfish, aquatic insects, and species of special

concern; commercial and recreational roles of aquatic

species; aquatic habitats; riparian areas; and wetlands.

Water Quality

Surface Water Quality (Streams). What are the

status and apparent trends of the water quality of

streams in the Highlands?

• Median concentrations of nitrite plus nitrate, ammonia,

total nitrogen, and total phosphorus collected at stream

sites near sewage treatment plants in most physiographic areas were significantly higher than at any

other type of site.

• Within the Boston Mountains, Springfield and Salem

Plateaus, and Arkansas Valley, nitrite plus nitrate

concentrations at stream sites increased significantly

with more intensive uses of land (e.g., acres of

“forest-pasture mix” had more of these concentrations

than did “forest” acres).

• Where more intensive uses of land occurred in the

Springfield and Salem Plateaus, Arkansas Valley, and

Ouachita Mountains, ammonia concentrations in

streams generally increased significantly. Within basins

that have significant “agriculture” land use, total

phosphorus concentrations were highest at stream

sites in the Arkansas Valley where land was used for

a mix of agriculture and forest activities.

• Concentrations of suspended solids were highest at

stream sites in the Osage Plains (just outside the

Highlands).

• From 1970 through 1990 at most stream sites in the

Ozark Plateaus Province, concentrations of nitrogen

and phosphorus forms and suspended solids did not

change substantially; this was also true from 1975

through 1995 for streams in the Arkansas Valley and

Ouachita Mountains.

Surface Water Quality (Lakes). What is the status

of the surface water quality of lakes within the

Assessment area?

• Within the Assessment area in Arkansas, 35 percent

of the 48 lakes were classified as mesotrophic, 63

percent as eutrophic, and 2 percent (1 lake) as

hypereutrophic.

• Within the Assessment area in Missouri, 13 percent of

the lakes were classified as oligotrophic, 32 percent as

mesotrophic, and 55 percent as eutrophic.

xiii
• Of the 30 Oklahoma lakes within the Assessment area,

3 percent were classified as oligotrophic, 30 percent

mesotrophic, 43 percent eutrophic, 17 percent

hypereutrophic, and 7 percent (2 lakes) as silt dominated.

Ground Water Quality. What are the status and

apparent trends of the quality of ground water in

the Highlands?

• The Springfield Plateau aquifer, the Ozark aquifer, and

aquifers of the Ouachita Province generally provide

water of excellent quality, though substantial differences in basic water chemistry occur among these

three settings.

• Ground water from springs differed substantially in

quality from that from wells in the Ozark aquifer, the

Springfield Plateau aquifer, and the aquifers of the

Ouachita Province. Springs in the Springfield Plateau

and Ozark aquifers are more susceptible to contamination from surface sources.

• Wide-ranging, inorganic concentrations observed in

aquifers in the Ouachita Province are indicative of

both the province’s diverse geochemical environments

and, for some water quality measures, the influential

land uses that are present.

• Background concentrations of nutrients in the Springfield Plateau and Ozark aquifers are low; nutrient

concentrations were below detection limits in many

samples collected from sites in heavily forested areas.

• Nitrite plus nitrate was detected more often and in

greater concentrations than any of the other nutrients.

Concentrations were greater than background concentrations in many samples from the Springfield Plateau

and Ozark aquifers and were positively correlated to

the percent of agricultural land use around each site.

Values ranged from less than 0.05 to 25 milligrams per

liter (mg/L) as nitrogen, with a median of 1.6 mg/L in

samples from the Springfield Plateau and Ozark

aquifers.

• In the Springfield Plateau and Ozark aquifers, median

nitrite plus nitrate concentrations generally were

greater in samples from springs than in samples from

wells.

• Concentrations of nitrite, ammonia, and ammonia plus

organic nitrogen were affected by land use in the

Springfield Plateau and Ozark aquifers.

• Background concentrations of nutrients in ground

water of the Ouachita Province are low; nutrient

concentrations were below detection limits in many

ground water samples. Nitrite plus nitrate was detected in samples of ground water from sites in the

Ouachita Province at concentrations ranging from

below detection limits to 4.7 mg/L as nitrogen, with a

median of 0.16 mg/L.

• The occurrence of nutrients in ground water in the

Ouachita Province did not show a statistically significant correlation with the percentage of agricultural

land use or urban land use around each site.

Aquatic Animals and their Habitats

Diversity of Fishes. What are the status and

distribution of fishes within the Assessment area?

• Twenty-four fish families are represented by native

species in the Assessment area, with five families

containing about 78 percent of the fish fauna of the

region; two families—the perches (Percidae) and

minnows (Cyprinidae)—comprise more than half of

the fish fauna.

• The fish faunas of the aquatic study area have been

classified into four distinct geographical regions based

on species composition as follows: the Ozark Fish

Faunal Region, Southern Ozark and Ouachita Mountain Fish Faunal Region, Big River Fish Faunal Region,

and Lowlands Fish Faunal Region—West Gulf Coastal

Plain-Mississippi Delta (Mississippi Alluvial Basin).

• In the northeastern part of the Assessment area,

native fish species richness is concentrated in the

Upper St. Francis River, Upper Black River, and

Upper White River drainages; in the west, it is concentrated in the drainages of the Neosho-Illinois Rivers

and western portions of the Arkansas River.

• Native fish species density varies across the Assessment area with the highest densities of fish species

associated with ecological-hydrologic units that are

generally small and species rich or small and adjacent

to species-rich units.

• Conservatively, at least 14 percent of the fish fauna is

endemic to the Assessment area (restricted to a

particular geographic area); endemic species are

distributed among five fish families, with highest

endemicity among darters and minnows. Endemic

fishes are concentrated in 2 ecological sections: the

Ozark Highlands (16 endemic fish species) and the

Ouachita Mountains (7 endemic fish species).

xiv
Diversity of Mussels. What are the status and

distribution of unionacean bivalves (mussels,

clams, naiads, or unionids) within the Assessment

area?

• Seventy-three species of native freshwater mussels

representing 37 genera occur within the Assessment

area. Eleven species are endemic to the Assessment

area, and there are two introduced species—the Asian

clam and the zebra mussel.

• Twenty-four freshwater mussel species are widely

distributed across the Assessment area; 16 species

occurring within the Assessment area are restricted to

streams draining the Ozark Highlands, and 8 species

are restricted to streams draining the Ouachita

Mountains.

• North American conservation status rankings for

freshwater mussel species in the Assessment area

reveal that 40 species are considered currently stable,

18 species are of special concern, 9 are ranked as

threatened, and 6 are listed as endangered.

• Ecological-hydrologic units with relatively high species

richness and density occur primarily in tier-like clusters

in the northeastern, central, and southern portions of

the Assessment area and appear to be associated with

hydrologic units possessing both headwater and main

stem habitats.

• The Aquatic Team calculated a relative importance

index value to rank hydrologic units in terms of combined mussel species richness, species density, and

habitat availability for rare species. The five highest

ranking hydrologic units were the Spring and Strawberry Rivers (Upper Black River Basin), the

Bourbeuse and Big Rivers (both in the Meramec River

Basin), and the Upper Ouachita River (OuachitaSaline River Basin).

Diversity of Crayfishes. What are the status and

distribution of crayfishes within the Assessment

area?

• Crayfish species representing 6 genera and 1 family

(Cambaridae) are present in the Ozark-Ouachita

Highlands Assessment area, and the genera

Orconectes (24 species), Procambarus (13 species),

and Cambarus (9 species) comprise 84 percent of the

crayfish fauna in the 50 hydrologic units.

• Crayfish species richness averaged 5.9 crayfish

species per hydrologic unit with a range of from 2 to

14 species; however, most hydrologic units showed

diverse crayfish faunas, with 29 of 50 units having

crayfish richness values greater than 4 species.

• The southeastern Ouachita Mountains and an area

trending southwest to northeast from the western

Boston Mountains to the eastern Ozark Plateaus

showed primary or secondary levels of crayfish

richness (6 to 14 species).

• Crayfish density averaged 0.4 species per 100 square

miles (mi2

) of a hydrologic unit and ranged from 0.1 to

0.9; 17 of 50 hydrologic units had densities equal to or

exceeding 0.5 crayfish species per 100 mi2

.

• Concentrations of hydrologic units with primary levels

of crayfish density occurred along the northeastern

edge of the Assessment area (Middle White unit,

Upper St. Francis unit, and most units in the Black

River and Meramec drainages) and in the southern

part of the Assessment area (most units in the

Ouachita-Saline drainage and the Lower Little unit of

the Kiamichi-Little drainage).

• The Ozark-Ouachita Highlands area supports at least

37 endemic crayfishes or 61 percent of the region’s

crayfish fauna; most of these endemic species are

confined to the Ozark Plateaus and Boston Mountains

(at least 22 endemic crayfishes), but endemicity is also

relatively high in the Ouachita Mountains (at least 13

endemic crayfishes).

Diversity of Aquatic Insects. What are the status

and distribution of aquatic insects within the

Assessment area?

• Streams and rivers of the Ozark-Ouachita Highlands

harbor a richness of species representing about 15

percent and 17 percent of all stoneflies and caddisflies,

respectively, known from North America. Eight

families, including 23 stonefly genera and 82 species,

and 17 families, including 57 genera caddisfly and 206

species, are known to occur in the Ozark-Ouachita

Highlands Assessment area.

• The Ouachita Mountains support the greatest richness

of stoneflies and caddisflies (195 species) in the

Assessment area. Nineteen of the regionally endemic

stonefly species occur in the Ouachita Mountains; six

of these occur in no other subregion. Three of the 13

xv
endemic caddisfly species (Cheumatopsyche

robisoni, Ochrotrichia robisoni, and Ochrotrichia

weddleae) found in the Ouachita Mountains are not

known elsewhere.

Endangered, Threatened, and Other Aquatic

Species of Special Concern. What are the status

and distribution of endangered, threatened, and

other aquatic species of special concern within

the Assessment area?

• A total of 125 aquatic taxa have 1 or more of the

following designations: Federal status (14 species),

globally imperiled through globally rare (78 taxa have

G1, G2, or G3 ranks), and State critically imperiled

(68 taxa have S1 ranks). Included are 7 insects; 37

mollusks, 35 of which are freshwater mussels; 23

crustaceans, 15 of which are crayfish; 55 fishes; and

3 herptiles (amphibians or reptiles).

• Of the 14 aquatic taxa with Federal status, 6 are

mollusks, 2 are crustaceans, and 6 are fishes.

• In the Assessment area, about 32, 50, and 26 percent

of fishes, mussels, and crayfishes, respectively, have

Federal status, globally rare ranks, and/or S1 State

ranks.

• Sixty percent of the hydrologic units recorded at least

one species with a Federal status on Element Occurrence Records (EOR’s); the pattern of distribution

(i.e., 0 to 4 species per unit out of 14 possible species) suggests that the presence of such species

differs dramatically across units.

• Hydrologic units with three or four species with

Federal status were located in the southern Ouachita

Mountains (Upper Little, Lower Little, and Upper

Ouachita units), in the Neosho-Illinois drainage (Lake

O’ the Cherokees, Illinois, Elk, and Spring units), and

in the Sac unit (Osage River drainage). Units with

one to two species with Federal status were scattered widely across the Assessment area.

• Two concentrations of hydrologic units showed

primary levels of endangered, threatened, and other

species of special concern (10 to 30 species with

Federal status, global ranks, or State ranks): (1) along

the southern edge of the Assessment area in the

Ouachita Mountains and (2) along the northeastern

edge of the Assessment area in the Upper Black

River and Upper St. Francis drainages. Secondary

levels of endangered, threatened, and other species

of special concern (seven to nine species per watershed) tended to be associated with hydrologic units

adjacent to those with primary levels.

Commercially and Recreationally Important

Species. What is the status of commercial and

recreational aquatic species within the Assessment area?

• Commercial fish harvesting within the Assessment

area is limited to Arkansas waters. The only legal

commercial fishing in Oklahoma occurs within the

Eufaula Reservoir just west of the Assessment

area, where one individual has a commercial

license.

• Commercial fish harvests and the number of commercial fishers are somewhat stable.

• Mussel harvesting regulations in Arkansas govern

whether an area is open, closed, or set aside as a

refugium (protected area) within an open area.

• Oklahoma had only one licensed shell (mussel) buyer

in 1997. The majority of the buying is of shells from

backwater areas of lakes in northeast Oklahoma; the

few species in this area with thick, large shells and

little surface erosion are in demand commercially.

• Demand for shells is driven by the market for pearl

blanks (a round piece of shell inserted in commercial

pearl oysters to stimulate pearl formation). Actual

harvest levels are lower than harvest limits because

of the pearl industry’s requirements for a specific

color and size.

• Legally designated species of game and commercial

fish vary by State, although sought-after species

differ little among States. Designating a species as a

game fish generally regulates its harvest more closely

than harvests of other recreational species.

• Significant efforts have been made—mostly introductions of non-native fish species—to manage openwater habitats of large reservoirs within the Assessment area and to utilize adequately cool and cold

water habitats within and downstream from these

reservoirs.

• State and Federal fisheries-management agencies

protect native stocks of smallmouth bass, walleye, and

sauger by foregoing some stocking opportunities that

might contaminate these native stocks genetically.

xvi
Where supplemental stocking is needed in habitats

containing protected native species, hatcheries are

using spawners of the same genetic stock as the

protected native species found in the receiving water

bodies.

Management Indicator Species. What management indicator species are located within the

Assessment area, and what is their potential role

for the aquatic resources?

• Lists of fish, mussels, crayfish, and aquatic insects

gathered during this Assessment include data about

their special status as reported and ranked by Federal

and State agencies, The Nature Conservancy, and

the American Fisheries Society (AFS); such rankings

can form the basis for the selection of management

indicator species for forest plan revision.

• The American Fisheries Society identified 19 fish, 76

mussel, and 59 crayfish species that occur in the

Highlands as endangered, threatened, of special

concern, and currently stable.

Aquatic Habitats. What is the status of the

aquatic habitats within the Assessment area?

• Over half of the hydrologic units in the Assessment

area have 10 or more stream types per hydrologic

unit (average = 8.7 stream types per hydrologic unit;

range of 5 to 15 per hydrologic unit), and no hydrologic unit has fewer than 5 stream types.

• Primary levels of stream type diversity (11 to 15

stream types per hydrologic unit) are located mostly

in the southern half of the Assessment area; secondary levels (10 stream types per hydrologic unit) are

located in hydrologic units along the periphery of the

Assessment area.

• Native fish species richness is associated significantly and positively with the number of different

stream types in hydrologic units.

• Numbers of endemic fish species and stream types

are not associated among hydrologic units.

• Hydrologic units with primary and secondary levels

of stream type diversity and native fish species

richness may be considered of particular significance

in maintaining present and future aquatic biodiversity

within the Ozark-Ouachita Highlands.

• Available analyses indicate that strong associations

exist between environmental variables (e.g., water

quality, geology, substrate) and the distribution of

fishes over much of the Assessment area, and any

pervasive alteration of existing habitat conditions

likely would affect the composition and distribution of

the fish fauna.

Riparian Areas. What are the extent and

vegetative composition of riparian areas within

the Assessment area?

• Of the almost 3 million acres of riparian areas

identified within the Assessment area, approximately

57 percent are forested, 37 percent are agricultural,

2 percent are urban, and 4 percent are classified as

“other.”

• The Upper Saline watershed has the greatest

percentage (87.4 percent) and the South Grand

watershed has the lowest percentage (14.9 percent)

of forested riparian cover in the study area.

• National forests generally have highly forested

riparian areas (86 to 93 percent).

Wetlands. What are the extent and composition

of wetlands within the Assessment area?

• Since the 1780’s, wetland losses in Assessment area

States have ranged from 50 to greater than 75

percent (Dahl 1990).

• Most of the State Soil Geographic data base soil-map

units that include hydric soils are found along the

Grand, Sac, Black, White, Arkansas, Ouachita, and

Little Rivers. These areas are potential wetlands

because they have saturated soils, one of the essential components of the designation “wetlands.”

• According to the State 305(b) inventory reports of

water quality, most of the wetlands in Arkansas,

Missouri, and Oklahoma have been converted to

agricultural production during historic times.

• Camden and Taney Counties, MO, and Pulaski

County, AR, had the most Clean Water Act 404

permits issued from 1988 through 1996. If the

number of permits issued indicates activity in wetlands and other water bodies, the Osage, Upper

White, and Arkansas River Basins had the most

activity from 1988 through 1996.

xvii
Chapter 3: The Clean Water Act and Aquatic

Restoration Programs

What laws, policies, and programs for the

protection of water quality, streams, wetlands,

and riparian areas are in place?

Federal and State laws and policies concerning

aquatic resources provide a legal mandate to ensure that

human activities are conducted with consideration for

the protection, preservation, and restoration of our

Nation’s water resources.

Chapter 3 discusses and summarizes many of the

laws and policies that are in effect and reviews the

success of these regulations to date. Topics specifically

addressed include: section 404 of the Clean Water Act

(CWA); the National Pollutant Discharge Elimination

System (NPDES); total maximum daily loads

(TMDL’s); and the control of nonpoint source pollution,

which includes best management practices (BMP’s).

In addition to laws, many federally funded programs

exist to protect, restore, or improve aquatic resources.

This chapter discusses and summarizes many of these

programs in the context of the Assessment area.

• There have been significant changes in regulations

that affect water resources, particularly regulations

concerning nonpoint source problems such as sedimentation and nutrient loading.

• Nonpoint source pollution is one of the major water

quality issues to contend with in the future.

• There are several U.S. Department of Agriculture

(USDA) incentive programs that focus on the

restoration of riparian areas and wetlands, including

the Wetlands Reserve Program (WRP) and Environmental Quality Incentive Program (EQIP).

Chapter 4: Effects of Human Activities

State and Federal Classifications of Water Quality

Outstanding Resource Waters (ORW’s). Which

streams and rivers have been designated as

Outstanding Resource Waters by pollution

control agencies in Missouri, Oklahoma, and

Arkansas?

• There are 4,113 stream miles (mi) of extraordinary,

ecologically sensitive, and legislatively designated

waters within the Assessment area. A single body of

water may fall within more than one of these categories.

• Of those miles, 17 percent occur on or adjacent to

national forest lands.

Impaired Waters. Which waters have pollution

control agencies in Missouri, Oklahoma, and

Arkansas determined to be impaired or threatened, and what are the suspected sources of

impairment?

• The State 305(b) lists identify 5,588 mi of impaired

streams within the Assessment area.

• The predominant sources of impairment of water

quality (primary and secondary sources combined)

within the Assessment area are agriculture (36.1

percent), unknown (10.9 percent), and mining (10.2

percent).

• Of the 5,588 mi of impaired streams, 133 are associated with national forest lands.

• Major sources of impairment for stream segments

within national forest lands include agriculture, road

construction, and silviculture.

EPA Index of Watershed Indicators (IWI).

How does the condition of Assessment area

watersheds compare with the rest of the United

States?

• Of the 50 watersheds within the Assessment area,

24 (48 percent) are designated as having “better

water quality and low vulnerability to stressors”

(pollutants that could further strain the aquatic

resource). Nationwide, EPA gave this rating to only 9

percent of watersheds.

xviii
• Within the Assessment area, only the Spring watershed in the Neosho-Illinois River Basin has a rating

of “more serious water quality problems and high

vulnerability to stressors.” The South Grand and

Fourche La Fave watersheds are in the following

class: “more serious water quality problems and low

vulnerability to stressors.”

Point Sources

CERCLA and Superfund Sites. What are the

current status and potential effects of hazardous

waste sites on aquatic resources within the

Assessment area?

• Within the Assessment area, there are 798 sites in

CERCLIS.

• Of the 798 sites, 15 are Superfund sites on the

National Priorities List (NPL).

National Pollutant Discharge Elimination System

(NPDES) Sites. What are the current status and

potential effects of permitted discharges on

aquatic resources?

• About 136 point sources currently discharge treated

wastewater into surface waters of the Assessment

area. Many of these sources with NPDES permits

are considered major facilities based on the volume

of discharge and pollutant loadings (concentrations of

pollutants in discharged effluent).

• The majority of the permit sources with discharges

greater than 1 million gallons per day (gal/d) are

municipal treatment facilities.

• Approximately 200 sewage treatment plants that

serve populations ranging from 1,000 to 132,000

discharge treated water into surface waters of the

Ozark-Ouachita Highlands. Average facility flows

range from 1,000 to 2 million gal/d. Larger municipal

sewage treatment plants include those of Springfield,

MO, and Little Rock, AR.

• Four industries constitute most of the point source

dischargers: sewage treatment plants, pulp mills, lead

and zinc ore operations, and electrical services.

• Of the four types of NPDES facilities that are ranked

as major, the largest number are found in the Lower

Neosho, Upper Black, and James River watersheds.

• Bull Shoals Lake watershed in the Upper White

River Basin has the most NPDES sites in the Assessment area.

Municipal Water Supplies. How do municipal

water facilities affect water quality within the

Assessment area?

• Municipal water supplies provide over 80 percent of

the drinking water in the Assessment area.

• The largest drinking water supplies are located in the

Meramec, Arkansas, Kiamichi, and Upper White

River Basins, which serve about 1.6 million people.

• Smaller water supplies in the Assessment area are

located in less populated watersheds such as the

Upper Black and Upper St. Francis River Basins.

Toxic Releases. What are the current status and

potential effects of toxic pollutants on aquatic

resources in the Assessment area?

• Densities of toxic release sites are highest in and

near urban areas such as Little Rock, AR; Fort

Smith, AR; Springfield, MO; St.Louis, MO; and

areas that have large industries or concentrations of

industries.

• The Spring (Neosho-Illinois River Basin), Lower

Arkansas-Maumelle, James, and Illinois watersheds

have the highest number and density of toxic release

sites in the region.

• Discharge media for toxic releases include land,

underground, air, water, and off-site transfer. Of

these media, air releases account for 53 percent of

all discharges.

Nonpoint Sources

Roads and Highways. What are the current status

and potential effects of roads and highways on

aquatic resources in the Highlands?

• All watersheds in the Assessment area have road

segments within 100 feet of streams.

• The Upper Black River, Bull Shoals Lake, Current

River, Beaver Reservoir, and Illinois River watersheds have the most road miles within riparian areas

in the Assessment area.

xix
• Class 2 and 3 roads (State highways and county

roads) have the highest number of miles within

Highlands riparian areas.

• Class 3 roads (county and national forest roads) have

the most miles within riparian areas in national

forests.

Agriculture and Silviculture. What are the current

status and estimated effects of potential erosion

from agriculture and silviculture on aquatic

resources within the Assessment area?

• Total potential erosion declined in more than half of

the watersheds in the Assessment area for the 3

years studied (1982, 1987, and 1992).

• The South Grand watershed had the highest average

potential erosion rate in 1992.

• Most of the cropland potential erosion as a percent of

total potential erosion came from watersheds along

the eastern and western boundaries of the Assessment area for the 3 years studied.

• The Fourche La Fave, Ouachita Headwaters, and

Upper Little River watersheds had the lowest

average potential erosion rates for the 3 years

studied.

• Forest potential erosion as a percent of total potential

erosion was 3 percent or less for most of the Assessment area watersheds for the 3 years studied.

• In 1982, 1987, and 1992, watersheds with the highest

forest potential erosion as a percent of total potential

erosion were in the southern part of the Assessment area.

• The category with the highest potential erosion in

most Assessment area watersheds for the 3 years

studied was pasture lands.

• Most watersheds in the Assessment area had no

appreciable potential erosion from rangelands.

• In more than half of the Assessment area watersheds potential erosion rates from “other” lands were

2 percent or less of total potential erosion.

Pesticides—Applications and Distributions.

Which pesticides are most frequently applied in

the Assessment area, and to what extent are they

distributed?

Ozark Plateaus

• Approximately 4.4 million pounds (lbs) of active

ingredients per year from 130 pesticides were applied

on 25 crop types within the Ozark Plateaus Province

from 1987 through 1991.

• The herbicides 2,4-D, atrazine, propanil, metolachlor,

alachlor, trifluralin, dicamba, and glyphosate were the

eight pesticides used most extensively on or in the

Ozark Plateaus.

• The most frequently applied pesticide was 2,4-D; an

estimated 750,000 lbs/year of 2,4-D were applied in

the Ozark Plateaus.

Arkansas Valley

• Approximately 771,000 lbs/year of active ingredients

from 128 pesticides were applied on 25 crop types

within the Arkansas Valley from 1987 to 1991.

• The seven pesticides used most extensively in the

Arkansas Valley were the herbicides 2,4-D, propanil,

trifluralin, atrazine, metolachlor, and dicamba and the

fungicide sulfur.

• The most frequently applied pesticide was 2,4-D; an

estimated 108,000 lbs/year of 2,4-D were applied in

the Arkansas Valley.

Ouachita Mountains

• Approximately 356,000 lbs/year of active ingredients

from 127 pesticides were applied on 22 crop types

within the Ouachita Mountains from 1987 to 1991.

• The herbicides 2,4-D, dicamba, atrazine, metolachlor,

trifluralin, and glyphosate and the fungicide, sulfur,

were the seven pesticides used most extensively in

the Ouachita Mountains.

• The most frequently applied pesticide in the Ouachita

Mountains was 2,4-D, with an estimated application

of 65,000 lbs/year.

xx
Pesticides in Surface Water. What are the current

and potential effects of pesticides on surface

water in the Highlands?

Ozark Plateaus

• Pesticide data are available for 1,002 samples from

141 surface water sampling sites in the Ozark

Plateaus.

• Many sites were sampled only once (42 sites) or

twice (19 sites) during the 1970 through 1990 period

of record.

• About 50 percent of the 1,002 samples were collected in the mid-1970’s and early 1980’s.

• Thirty-four of the 50 pesticides were below the

detection limit for all the samples collected; 16

pesticides were detected in 132 samples collected

from 43 sites.

• The pesticide detected most often was the insecticide

toxaphene, detected in 17 of 866 samples from 5 of

112 sites. The concentration of toxaphene in samples

with detections ranged from 0.1 to 6.0 mg/L.

Arkansas Valley

• Pesticide data are available for 53 samples from 14

sites in the Arkansas Valley.

• Many sites were sampled only once (four sites) or

twice (seven sites) during the 1975 through 1995

period of record.

• About 65 percent of the 53 samples were collected in

the early and mid-1980’s.

• Three of the nine pesticides were below the detection limit for all the samples collected; six pesticides

were detected in three samples collected from three

sites.

• Five pesticides (DDE, DDT, aldrin, dieldrin, and

lindane) were detected in 3 of 53 samples from 3 of 14

sites. The maximum concentration for these pesticides

was 0.001 mg/L, except for DDT (0.002 mg/L).

Ouachita Mountains

• Pesticide data are available for 245 samples from 19

sites in the Ouachita Mountains.

• About 64 percent of the 245 samples were collected

in the late 1970’s and early 1980’s.

• Sixteen of 23 pesticides were below the detection

limit for all the samples collected; 7 pesticides were

detected in 13 samples collected from 10 sites.

• The most commonly detected pesticide was methyl

parathion, found in 10 of 234 samples at 10 of 20

sites, which had concentrations ranging from 0.001 to

0.002 mg/L.

Pesticides in Ground Water. What are the current

and potential effects of pesticides on ground

water in the Highlands?

Ozark Plateaus Province

• Pesticides were detected in 80 of 229 samples of

ground water from 73 of 215 sites.

• Twenty pesticides were detected; a maximum of five

pesticides was detected in any one sample.

• The most commonly detected pesticides are

tebuthiuron, atrazine, prometon, desethylatrazine, and

simazine. Maximum concentrations range from 0.003

to 1.0 mg/L.

• The occurrence and distribution of pesticides are

related to land use. Samples with detectable pesticides come from sites having a higher percent of land

used for agriculture than samples from sites with no

pesticides detected.

• Pesticides are detected more often in samples from

springs than in samples from wells.

Ouachita Province

• For the Ouachita Province, very little data are

available from monitoring pesticides in ground water.

• Commonly applied pesticides in forest land—2,4-D,

dichlorprop, hexazinone, and picloram—were not

found at any of the eight Ouachita Mountains sites

sampled in 1986.

Animal Wastes. What are the current status and

potential effects of animal confinement and

waste on aquatic resources in the Assessment

area?

• An estimated 358,300 tons (7 tons/mi2) of nitrogen

and 123,400 tons (3 tons/mi2

) of phosphorus were

available from animal wastes in the Ozark Plateaus

in 1992.

xxi
• An estimated 82,312 tons (6 tons/mi2

) of nitrogen and

29,460 tons (2 tons/mi2

) of phosphorus were available

from animal wastes in the Arkansas Valley in 1992.

• An estimated 57,555 tons (4 tons/mi2

) of nitrogen and

20,207 tons (2 tons/mi2

) of phosphorus were available

from animal wastes in the Ouachita Mountains in

1992.

Fertilizers. What are the current status and

potential effects of fertilizer applications on

aquatic resources within the Assessment area?

Ozark Plateaus Province

• In 1985, nitrogen fertilizer application rates for the

counties within the Ozark Plateaus part of the

Assessment area ranged from an estimated 0 to 12

tons/mi2

.

• Phosphorus fertilizer application rates in 1985 for the

counties within the Ozark Plateaus ranged from an

estimated 0 to 5 tons/mi2

.

Arkansas Valley

• In 1985, nitrogen fertilizer application rates for the

counties within the Arkansas Valley part of the

Assessment area ranged from an estimated 0 to 12

tons/mi2

.

• Phosphorus fertilizer application rates in 1985 for the

counties within the Arkansas Valley ranged from an

estimated 0 to 1 ton/mi2

.

Ouachita Mountains

• In 1985, nitrogen fertilizer application rates for the

counties within the Ouachita Mountains part of the

Assessment area ranged from an estimated 0 to 3

tons/mi2

.

• Phosphorus fertilizer application rates in1985 for the

counties within the Ouachita Mountains ranged from

an estimated 0 to 0.5 ton/mi2

.

Urbanization. What are the current status and

potential effects of urbanization on aquatic

resources within the Assessment area?

• The 1990 population of the Assessment watersheds

was 3,361,301.

• Between 1980 and 1990, an 8 percent population

increase occurred within the Assessment watersheds.

• Twenty-four watersheds experienced population

increases of 7 percent or more between 1980 and

1990.

• Between 1980 and 1990, the rate of urbanization was

greater within the Assessment area than nationwide.

• Two Assessment area watersheds (the Upper Little

River in southeastern Oklahoma and the Little

Missouri in southern Arkansas) had a 7 percent

decrease in population from 1980 to 1990.

Mineral Extraction. What are the current status

and potential effects of activities associated with

the exploration and extraction of minerals on

aquatic resources within the Assessment area?

• In 1996, approximately 692 mining-related operations

for hardrock and coal extraction occurred in the

Assessment area.

• The primary mining activity in the Assessment area

is surface mining of common variety minerals that

generally go to the building and road construction

industries.

• Several abandoned, historical mine sites continue to

contribute to chemical and metal leachates and

runoff, increasing acidity in some cases and affecting

aquatic resources within the Assessment area.

• Effects on aquatic resources from present-day

mining activities are primarily associated with increased sedimentation of streams caused by instream

gravel and sand extraction.

• Approximately 595 mi of rivers, streams, and lakes

are impaired as a result of mining activities within the

Assessment area.

Introduced Species. What effects are introduced

aquatic species having on the Assessment area?

• Introduced species such as zebra mussels, common

carp, and a number of aquatic weeds have become

pests.

xxii
• Arkansas, Missouri, and Oklahoma are making

concerted efforts to retard the spread of zebra

mussels both through general public education and

the education of individual anglers and boaters.

• It is likely that zebra mussels eventually will show up

in most lakes and reservoirs in the Assessment area

as the result of a transient boating public. Zebra

mussels are expected to ravage the native mussel

fauna as well as disrupt the food chain of any water

body they colonize.

• Nonindigenous species (non-native or transplanted

species) require constant management attention to

reduce the likelihood of introduced species, particularly exotics (non-natives), becoming established.

Chapter 5: Water Supply and Use

Past and Present Supply and Use. What are the

past and current water supplies and uses in the

Assessment area?

• Total withdrawals in the Assessment area in 1995

were 6,622 million gal/d. Of these withdrawals, 1,322

million gal/d (20 percent) were consumed and not

returned to a stream.

• Twenty-two percent of the total 1995 withdrawals

came from ground water pumping; the other 78

percent of withdrawals came from surface water.

• Hydropower plants used almost 103 billion gal/d of

surface water to produce electricity.

• From 1985 to 1995, withdrawals increased in four

categories of water use (domestic and public, commercial, thermoelectric, and irrigation) and decreased

in three other categories (industrial, mining, and

livestock).

• Increases in withdrawals, especially those at thermoelectric plants and for irrigation, far outpaced decreases, resulting in substantial net increases.

• In 1995, 64 percent of withdrawn water was for

cooling at thermoelectric plants; another 20 percent

was for crop irrigation.

• Annual precipitation in the Assessment area averages about 44 inches, of which roughly 70 percent

evaporates. The rest is available as streamflow, to

recharge ground water reservoirs, or for offstream

use.

• Across the entire area in the average year, only 6.7

percent of the 53.7 billion gal/d of water yield is

withdrawn for offstream use, and only 1.2 percent

evaporates or returns to the stream.

• Withdrawals vary widely across watersheds and

exceed 20 percent of available water in four watersheds. In three of these watersheds (South Grand,

Illinois, and Dardanelle Reservoir), withdrawals for

thermoelectric plants account for 83 to 97 percent of

total withdrawals. In the other watershed (Lower

Black), irrigation accounts for 97 percent of total

withdrawals.

Future Patterns and Trends. What future trends

are likely for water use and supply?

• Domestic and public withdrawals are projected to

increase from 143 gal/day per person in 1995 to 156

in 2040. Total domestic and public withdrawals are

thus projected to increase from 538 million gal/d in

1995 to 675 in 2040.

• Total industrial and commercial withdrawals are

projected to drop from 339 million gal/d in 1995 to

214 in 2040

• Total annual energy production at thermoelectric

plants in the Assessment area is projected to increase from 75 billion kilowatt hours (kWh) in 1995

to 107 billion kWh in 2040.

• Total withdrawals for thermoelectric plants are

projected to drop from 4.2 billion gal/d in 1995 to 3.8

in 2040.

• Acres of crops irrigated are expected to increase

from 798 thousand in 1995 to 1,226 thousand in 2040.

Total irrigation withdrawals are projected to increase

from 1.3 billion gal/d in 1995 to 2.0 billion gal/d in

2040.

• Total withdrawals are projected to increase until 2020

and remain rather stable after that, staying within 5

percent of 1995 withdrawals. Essentially the increases in withdrawals for domestic and public use

and for irrigation are largely balanced by the decreases in withdrawals for industrial, commercial,

and thermoelectric uses.

xxiii
Kansas

Oklahoma

Missouri

Arkansas

Aquatic study area

Physiographic province

boundary

Physiographic section

boundary

Ozark Plateaus Province

Ouachita Province

Osage Plain

Salem Plateau

Springfield Plateau

St. Francois

Mountains

Springfield Plateau

Salem Plateau

Boston Mountains

Arkansas Valley

Ouachita Mountains

West Gulf Coastal Plain

Mississippi

Alluvial

Plain

Central Lowland

Province

Province

Coastal Plains

Osage

Plains

Figure 1.1—Physiographic subdivisions of the aquatic study area (adapted from Fenneman 1938).

xxiv
Chapter 1: Introduction to the Aquatic Study Area

This introductory chapter of the Ozark-Ouachita

Highlands Assessment: Aquatic Conditions describes the

physiography, river basins, watersheds, major lakes, ground

water, climate, geology, soils, and land uses of the aquatic

study area and the slightly smaller Highlands Assessment

area. The Aquatic Team used physiographic areas, river

basins, and watersheds as the principal geographic units for

displaying data throughout most of this report. (The exception is in the latter half of Chapter 2, where “ecological

sections” are substituted for physiographic areas, as

described in the text at that point.) An understanding of

physiographic areas, river basins, watersheds, and the other

background information in this chapter will provide the

reader with a context for the chapters that follow.

Physiography

For the portions of this report that use physiographic

areas as mapping or descriptive units, the Aquatic Team

used Fenneman’s (1938) definitions and terminology. A

physiographic “province,” for example, is a geographic

area having particular geologic and landform characteristics. The study area for the aquatic portion of the Assessment included the Ozark Plateaus Province, the Ouachita

Province, and small parts of the Coastal Plains and

Central Lowland Provinces (fig. 1.1). (Portions of the

Coastal Plains Province and the Central Lowland Province were included in the aquatic study area to encompass

watersheds that lie partially within and partially outside the

Highlands.) These four provinces include diverse topography, geomorphology, and soils that greatly influence the

aquatic ecosystems of the Ozark-Ouachita Highlands.

Altitudes of land surfaces in the aquatic study area

range from approximately 200 feet (ft) above mean sea

level in the Coastal Plains Province to more than 2,300 ft

in the Boston Mountains of the Ozark Plateaus Province

and over 2,700 ft in the Arkansas Valley and the

Fourche-Kiamichi Mountains of the Ouachita Province.

Ozark Plateaus Province

The Ozark Plateaus Province covers an area of 40,000

square miles (mi2

) and includes parts of four States. The

physiography of this province is largely defined by its

geology, which consists of a vast structural dome of

igneous rocks (forming the St. Francois Mountains in

southeastern Missouri). This dome is flanked by sedimentary rocks that gently dip away to form three distinct

physiographic sections (Fenneman 1938): (1) the Salem

Plateau (including the St. Francois Mountains), (2) the

Springfield Plateau, and (3) the Boston Mountains (fig.

1.1). Topography ranges from “gently rolling hills” in the

Springfield Plateau through “rugged landscapes with

relief up to 500 ft” in the Salem Plateau to “extremely

rugged with relief as much as 1,000 ft” in the Boston

Mountains.

The southeastern boundary of the province is marked

by contact between Paleozoic Era rocks of the Ozark

Plateaus and younger, unconsolidated sediments of the

Mississippi Alluvial Plain. The southern provincial boundary is defined by faults on the southern flank of the

Boston Mountains. The western boundary is marked by

contact between rocks of Mississippian and Pennsylvanian age. The northern and eastern boundaries of the

province generally follow the Missouri and Mississippi

Rivers, respectively.

The highest land surface altitude in the Ozark Plateaus, excluding the Boston Mountains (where altitudes

exceed 2,300 ft), is 1,772 ft above sea level at Taum

Sauk Mountain (part of the St. Francois Mountains). A

ridge of locally high relief extends west-southwest from

the St. Francois Mountains to the extreme southwestern

corner of Missouri. Altitudes along this ridge range from

the peak of Taum Sauk Mountain down to about 1,200 ft;

altitudes generally decrease moving away from this ridge

to the northwest (toward the Osage Plains) or south.

The varied (nearly flat to very rugged) provincial

topography is marked by boundaries between plateau

highs that form escarpments where deeply incised valleys

separate narrow divides or “mountains.” Here, the result

is rugged topography with relatively high relief. Away

from the escarpments, the topography is composed of

nearly flat lands that rise to gently rolling hills with low

relief. The exception is the Boston Mountains, which

have pervasively rugged topography (Fenneman 1938).

Throughout much of the Ozark Plateaus, stream

drainage patterns are radial. Drainage patterns can
follow geologic features such as faults and joints in the

rocks. Entrenched stream meanders, resulting from

streams downcutting as the area was uplifted, are

common in the larger stream valleys. In the more rugged

parts of the Salem Plateau and Boston Mountains,

drainage patterns are dendritic (branching).

The Ozark Plateaus Province contains numerous

distinctive geomorphic (surface) features that are related

to the geology and hydrology of the area. For example,

local uplands can form two distinct landscape features—

mounds and bald mountains. Mounds are erosional

remnants of outliers of rocks of Mississippian or Pennsylvanian age overlying older sedimentary rocks. Bald

mountains, commonly called “balds,” are predominantly

treeless hills present in south-central Missouri. Lines of

trees on bald mountains can indicate water-bearing

fractures in the underlying rock (Beveridge and Vineyard

1990).

Karst limestone features are common in the Ozark

Plateaus. Dissolution of carbonate rocks along fractures and

faults has produced cave systems, sinkholes, and natural

tunnels in the area (Beveridge and Vineyard 1990). Missouri

alone has at least 5,000 caves, and most of these are located

in the Ozark Plateaus Province (MO DNR 1980).

Salem Plateau

The Salem Plateau covers a large part of the aquatic

study area (approximately 27,200 mi2

) in Missouri and

northern Arkansas (fig. 1.1). Underlain by rocks of

Cambrian and Ordovician age, the Salem Plateau contains a central upland area. Topography in this upland—

located west of the St. Francois Mountains—typically

consists of gently rolling hills with local relief from 50 to

100 ft (Fenneman 1938). Away from the central upland

area, numerous streams dissect the plateau, resulting in

increased relief. South and east of the upland, topography

is rugged, with local relief up to 500 ft. North of the

central upland, topography is also rugged, but relief rarely

exceeds 350 ft (Fenneman 1938).

Sinkholes and springs are abundant in the Salem

Plateau. The upland area has an average of 1 to 10

sinkholes per 100 mi2

. A north-south trending band in

south-central Missouri contains more than 10 sinkholes

per 100 mi2

 (Harvey 1980). Springs generally have

discharges exceeding 100 cubic feet per second (ft3

/s)

(Imes and Smith 1990).

The St. Francois Mountains are formed from exposures of igneous rocks of Pre-Cambrian age associated

with the structural dome of similar makeup in southeastern Missouri. The St. Francois Mountains are a series of

resistant hills or knobs separated by valleys that are

underlain by sedimentary rocks of Cambrian age. While

the St. Francois Mountains cover about 1,350 mi2

, the

area in which predominantly igneous rocks are exposed is

less than 100 mi2

. Altitudes of land surfaces range from

1,000 to more than 1,700 ft above sea level. Topography

is rugged, with local relief ranging from 500 to 800 ft

(Fenneman 1938). The St. Francois Mountains are not a

separate physiographic section as defined by Fenneman

(1938) but will often be discussed separately in this report

because of unique geological features that affect the

hydrology of the area.

Springfield Plateau

The Springfield Plateau covers approximately 13,400

mi2

, including parts of west-central and southwestern

Missouri, southeastern Kansas, northeastern Oklahoma,

and northern Arkansas (fig. 1.1). Limestones and cherty

limestones of Mississippian age underlie the plateau

(Fenneman 1938).

Altitudes of land surfaces in the Springfield Plateau

range from 1,000 to 1,700 ft, but local topographic relief,

which decreases from east to west, rarely exceeds 200 to

300 ft. The topography is mostly gently rolling hills, except

at the Eureka Springs Escarpment (which separates the

Springfield and Salem Plateaus), where deeply incised

stream valleys separate narrow divides (Fenneman 1938).

Sinkholes and springs are common in the Springfield

Plateau, but generally are smaller and less abundant than

in the Salem Plateau. The number of sinkholes in the

Springfield Plateau averages less than 1 per 100 mi2

,

except near the city of Springfield, MO, where there are

more than 10 sinkholes per 100 mi2 (Harvey 1980).

Boston Mountains

The Boston Mountains occupy approximately 2,400

mi2

 in a 200-mile-wide band extending through northern

Arkansas and northeastern Oklahoma (fig. 1.1). Sandstones, shales, and limestones of late Mississippian to

Pennsylvanian age underlie the Boston Mountains.

Altitudes in the Boston Mountains range from land

2
surfaces that are 1,200 to more than 2,300 ft above sea

level. Topographic relief is as much as 1,000 ft in some

places, and topography typically is rugged, with narrow

divides separating steep-sided valleys (Fenneman 1938).

Ouachita Province

The Ouachita Province lies in west-central Arkansas

and eastern Oklahoma. Its physiographic sections are

defined by the contrasting nature of the geologic structure

observed in each. The Arkansas Valley—the northern

section of this province—consists of gently to moderately

folded rocks exclusively of Pennsylvanian age. Further

south, the Ouachita Mountains section consists of the

remnants of heavily eroded roots of a mountainous belt.

Similar in structure and topography to the Appalachians,

the mountains are characterized by gently to intensely

folded and faulted strata (layers of rock). The Ouachita

Mountains have three distinct districts: the FourcheKiamichi Mountains, the Novaculite Uplift, and the

Athens Piedmont Plateau (Fenneman 1938).

The northern and northwestern boundaries of the

Ouachita Province form a common boundary with the

Boston Mountains, as described above. The eastern

boundary of this province is marked by contact between

Paleozoic rocks with younger, unconsolidated sedimentary strata of the Mississippi Alluvial Plain, called the Fall

Line. The southern boundary is defined by the contact of

Paleozoic Era rocks with unconsolidated sedimentary

strata of the Coastal Plains Province.

Altitudes of land surfaces in the Ouachita Province

range from less than 300 ft to more than 2,750 ft above

sea level. Topography ranges from “flat” in the Arkansas

River floodplain through “rolling” in the Athens-Piedmont

Plateau to “rugged” in the Ouachita Mountains interior.

Drainage patterns are typically trellis type and are

strongly influenced by geologic structure. Streams tend to

follow lines of folding and faults.

Arkansas Valley

The Arkansas Valley is located along the Arkansas

River between Muskogee, OK, and Little Rock, AR, and

is distinguished from the Ouachita Mountains section by

its structure. The valley has open, gentle folding resulting

in isolated, synclinal mountains, while the Ouachita

Mountains have intense geologic folding and faulting

resulting in tightly spaced, east-west trending linear ridges.

All consolidated rocks of the Arkansas Valley are of

Pennsylvanian age and compose a sequence of predominantly clastic (fragmented) rocks of great thickness (more

than 30,000 ft deep in some areas).

The synclinal mountains are an outstanding feature of

the Arkansas Valley: these erosional remnants present

the highest elevations of land in the Assessment area.

They are isolated, steep-sided buttes, often with 2,000 ft

or greater local relief. Sandstone layers in these synclinal

troughs are nearly horizontal. During folding, the upper

part of the less ductile or less malleable sandstone layers

was less compressed and more gently fractured. The

result was more resistant rock that contributed to the

formation of the synclinal mountains.

A large area of the Arkansas Valley consists of rolling

lowland that lies between mountain and ridge areas and is

less than 600 ft in elevation. These areas give way to

swampy alluvial plains near the Arkansas River. The

Arkansas River primarily drains the valley. However, the

Little Red River drains the northeastern corner of the

Arkansas Valley, and several bayous that flow across the

West Gulf Coastal Plain drain the southeastern edge.

Ouachita Mountains

The Ouachita Mountains section is a lens-shaped

physiographic area stretching from Little Rock, AR, to

Atoka, OK. It consists of tightly compressed, folded, and

faulted strata with fault traces and fold axes generally

trending east to west.

The Fourche-Kiamichi Mountains (no boundaries are

shown on fig. 1.1 for this or the two other districts in the

Ouachita Mountains) constitute about two-thirds of the

Ouachita Mountains. This district consists of roughly

equal segments of uneven valley floor and interceding

rugged mountain ridges and relief. Mountain altitudes

range from around 600 ft in the easternmost part of the

district near Little Rock to more than 2,500 ft in the

central area of the section. Valley floor altitudes range

from approximately 400 ft or less in the eastern part to

1,100 ft above sea level in the central parts.

The Novaculite Uplift defines the core area of the

Ouachita Province where uplift during the Ouachita

orogeny (mountain building era) was greatest. Carboniferous and younger strata have eroded entirely away. The

resulting exposed rocks are resistant to erosion and

3
contribute to the district’s distinctive hydrogeology

(water and terrain interactions). Resistant sandstones

form mountains of 600 to 2,000 ft in altitude separated

by broad basins underlain by less resistant shales. Local

relief typically ranges from 300 to 700 ft. The hot

springs for which the Novaculite Uplift is famous are

found on the plunging crestline of one of the district’s

many overturned anticlines.

The Athens Piedmont Plateau, located in the southernmost part of the Ouachita Mountains, is an erosional

plateau with no mountains. Stratigraphy (the arrangement of layers) and structure in this district are similar

to that observed in the district to the north. However,

the plateau shows only minor topographic relief, with

occasional east-west trending ridges and swells. Parallel

sandstone ridges rise 150 to 250 ft above narrow,

interceding valleys. Altitudes range from 1,100 ft at the

western end of the piedmont to 400 ft above sea level in

the southeast. The ranges generally slope to the south

and east. The larger streams flow south across the

district and generally have steep gradients (15 to 20 ft

per mile); tributaries follow strike-trending valleys and

intersect at right angles (Fenneman 1938).

Approximately two-thirds of the Ouachita Mountains section drains to the Red River Basin through

the Ouachita River and its tributaries. The northern

part of the section is in the Arkansas River Basin,

drained primarily by the Fourche La Fave River and

its tributaries.

Central Lowland and Coastal Plains Provinces

The Central Lowland Province occupies a large area

in the Central United States extending from Texas to

North Dakota and from Missouri to Colorado

(Fenneman 1938). The Osage Plains portion of this

province includes an area just west of the Assessment

area that drains portions of the Ozarks.

The Coastal Plains Province extends along the

Atlantic and Gulf Coasts from New England to Texas. It

is a continuation of the Continental Shelf and has a very

gentle slope. The Mississippi Alluvial Plain section of this

province, which is an area of deltas and bottomlands of

the Mississippi River and its tributaries, includes a small

area in the eastern part of the aquatic study area. A

small part of the West Gulf Coastal Plain section lies in

the extreme southern part of the aquatic study area.

Osage Plains

The Osage Plains occupies approximately 6,700 mi2

in the western and northwestern part of the aquatic

study area (fig. 1.1). Soft shales with interbedded

sandstones and limestones of late Mississippian to

Pennsylvanian age underlie the Osage Plains. Altitudes

of land surfaces in the study area portion of the Osage

Plains range from 800 to 1,000 ft above sea level, and

topography consists of gently rolling hills. In a few

places, resistant beds of sandstones and limestones form

rare, east-facing escarpments (Fenneman 1938).

Mississippi Alluvial Plain

The Mississippi Alluvial Plain section lies immediately

east of the Assessment area (fig. 1.1). Unconsolidated

sediments of Cretaceous through Quaternary age

underlie the flat to gently rolling plain. The land surface

of the Mississippi Alluvial Plain located in the aquatic

study area averages less than 200 ft above sea level;

the range of topographic relief seldom exceeds 30 ft.

Geologic structure and erosion have contributed to

the formation of the plains. The boundary between the

unconsolidated sedimentary strata of the Mississippi

Alluvial Plain and sedimentary rocks of Paleozoic age is

formed by normal faults. Faulting has resulted in

subsidence of the older sedimentary rocks, allowing a

thick sequence of unconsolidated sedimentary strata to

be deposited on top. The Mississippi River and its

tributaries have eroded the unconsolidated sedimentary

strata in places, forming occasional bluffs and ridges in

the section (Fenneman 1938).

West Gulf Coastal Plain

The West Gulf Coastal Plain section is located south

of the Ouachita Province and marks the contact between Cretaceous and Paleozoic rocks. Unconsolidated

sediments of Cretaceous age underlie the mildly rolling

West Gulf Coastal Plain. Streams are low gradient and

generally follow parallel southeasterly courses.

Major River Basins

The Assessment area is drained by 10 major river

basins (clockwise from the northeast): the Meramec,

Upper St. Francis, Upper Black, Upper White,

4
Ouachita-Saline, Kiamichi-Little, Arkansas, NeoshoIllinois, Osage, and Gasconade. Nested within these

river basins are 50 smaller watersheds (hydrologic units)

(fig. 1.2). These waters are all direct or indirect tributaries of the Mississippi River. The Black River is a

tributary of the White River, which flows directly into the

Mississippi River, as do the Meramec and St. Francis

Rivers. The Neosho and Illinois Rivers are tributaries of

the Arkansas River, which flows into the Mississippi

River. The Osage and Gasconade Rivers flow into the

Missouri River, which is the largest of the Mississippi

River tributaries. The Kiamichi, Little, Ouachita, and

Saline Rivers are tributaries of the Red River, which

flows directly into the Mississippi River. Table 1.1

provides summary information about these river basins,

and a more detailed description of each follows.

Oklahoma

Arkansas

Missouri

Spring

(11070207)

Current

(11010008)

Sac (10290106)

Meramec

(07140102)

Bull Shoals Lake

(11010003)

Beaver Reservoir

(11010001)

Illinois

(11110103)

South Grand

(10290108)

Lower Neosho

(11070209)

Little Red

(11010014)

James

(11010002)

Upper Black

(11010007)

Buffalo

(11010005)

Big

(07140104)

Elk

(11070208)

Spring

(11010010)

North Fork White (11010006)

Upper Gasconade

(10290201)

Middle White

(11010004)

Dardanelle Reservoir

(11110202)

Niangua

(10290110)

Petit Jean

(11110204)

Eleven Point

(11010011)

Upper

St. Francis

(08020202)

Ozarks

(10290109)

Lower Osage

(10290111)

Cadron

(11110205)

Bourbeuse

(07140103)

Lower

Gasconade

(10290203)

Big

Piney

(10290202)

Strawberry

(11010012)

 

Harry S. Truman

Reservoir

(10290105)

Pomme

de Terre (10290107)

Lake ConwayPoint Remove

(11110203)

Lake O' the

Cherokees

(11070206)

Osage River Basin

Neosho-Illinois

River Basin

Arkansas

Kiamichi-Little

Ouachita-Saline

River Basin

Upper White

Upper St. Francis

River Basin

Meramec

River Basin

Upper Black

 

Gasconade

River basin boundary

Watershed boundary

Black

(11010009)

Lower

Dirty-Greenleaf

(11110102)

Poteau

(11110105)

Frog-Mulberry

(11110201) Robert S. Kerr

Reservoir

(11110104)

Fourche La Fave (11110206)

Lower ArkansasMaumelle

(11110207)

Little Missouri

(08040103)

Upper Saline Upper Ouachita (08040203)

(08040102)

Ouachita Headwaters

(08040101)

River Basin

Kiamichi

(11140105)

Lower Little

(11140109)

Upper Little

(11140107)

Mountain Fork

(11140108)

River Basin

Lake of the

River Basin

River Basin

River Basin

Figure 1.2—Major river basins and watersheds (with hydrologic unit codes) of the aquatic study area.

5
Table 1.1—Major river basins of the aquatic study area and their drainage areas, land uses, principal tributaries, and major

reservoirs, by principle physiographic area

Total Drainage Land use, in Drainage Major reservoirs within

drainage within aquatic order of area of basin (not necessarily in

River basin area study area importance Principal tributaries tributaries named tributaries)

 - - - - - - - - - Mi2

 - - - - - - - - - Mi2

Ozark Plateaus Province

Upper Whitea 27,800 13,000 F, P, C, U War Eagle Creek 332 Beaver Reservoir

Kings River 565 Table Rock Lake

Crooked Creek 462 Lake Taneycomo

Buffalo River 1,340 Bull Shoals Lake

Little Red River 1,792 Norfork Lake

James River 1,460 Greers Ferry Lake

North Fork White River 1,830

Neosho-Illinois 14,100 7,800 C, P, F, M Spring River 3,510 Lake O’ the Cherokees

Elk River 872 Lake Hudson

Big Cabin Creek 450 Fort Gibson Lake

Osage Creek 206 Tenkiller Ferry Lake

Baron Fork 307

Osage 15,300 9,600 C, P, F, M Little Osage River 570 Truman Reservoir

Marmaton River 1,150 Lake of the Ozarks

South Grand River 2,040 Stockton Lake

Sac River 1,970 Pomme de Terre Lake

Pomme de Terre River 828

Niangua River 1,040

Gasconade 3,600 3,600 F, P Big Piney River 760 None

Osage Fork 520

Roubidoux Creek 300

Little Piney Creek 272

Meramec 3,980 3,960 F, P, M Bourbeuse River 841 None

Big River 964

Upper St. Francis 6,480 1,310 F, P, M NA NA Lake Wappapello

Upper Black 8,560 8,560 F, A, M Current River 2,610 Clearwater Lake

Spring River 1,230

Eleven Point River 1,220

Strawberry River 792

Ouachita Province

Arkansas 160,600 12,900 F, A, U Poteau River 1,890 Robert S. Kerr Lock/Dam

Mulberry River 511 Wister Reservoir

Petit Jean River 1,080 Nimrod Lake

Cadron Creek 753 Blue Mountain Lake

Big Piney Creek 537 Webber Falls Lock/Dam

Fourche La Fave River 1,120 Ozark Lake

Maumelle

Ouachita Mountains

Ouachita-Saline 18,900 7,100 F, A Caddo River 477 Lake Ouachita

Little Missouri River 2,103 DeGray Lake

Saline River 1,716 Winona

Hurricane Creek 312 Lake Greeson

Lake Hamilton

Kiamichi-Little 6,000 6,000 F, A Cossatot River 541 Millwood Lake

Mountain Fork 865 Sardis Lake

Broken Bow Lake

Hugo Lake

Mi2

 = square mile; F = forest; P = pasture; C = cropland; U = urban; M = mining; A = agriculture (both pasture and cropland); NA = not applicable. a Does not include the Black River Basin, which is the largest tributary of the White River; the drainage area for the Kings River does not include the

small part in Missouri.

6
Three national forests—the Ozark, Ouachita, and Mark

Twain—lie wholly or partially within the river basins of the

aquatic study area. The St. Francis National Forest,

administratively linked with the Ozark, lies outside of the

Assessment area. Table 1.2 displays the acreage of national

forest lands within each watershed of the study area and

the portion of each watershed occupied by such lands.

National forest lands are present in 9 of the 10 river basins

and in 34 of the 50 watersheds. (Comparable data for other

public lands are not presented here, primarily because, with

the exception of a few counties, national forests are by far

the most prominent public lands in the Highlands.)

Ozark Plateaus Province

Adamski and others (1995) describe the major river

basins of much of the Ozark Plateaus. Most of the

following discussion is based on that report.

Upper White River Basin

The White River, originating in the rugged terrain

of the Boston Mountains of northwestern Arkansas,

generally flows northward to the Arkansas-Missouri

State line, then eastward through southern Missouri

for about 115 miles (mi) where it again intersects the

Arkansas-Missouri State line (fig. 1.3). The river

meanders on either side of the Arkansas-Missouri

boundary for about 30 mi, flows southeastward into

Arkansas to the mouth of the Black River, and then

south to its confluence with the Mississippi River. The

total drainage area of the White River is 27,800 mi2

,

with about 10,600 mi2

 in southern Missouri and 17,200

mi2

 in northern and eastern Arkansas (Sullavan 1974).

About 13,000 mi2

 (not including the Upper Black

River Basin) are in the Ozark Plateaus segment of the

aquatic study area. The stream reach of the White

River near the Arkansas-Missouri State line is marked

by a series of reservoirs, beginning with Beaver Lake

in northwestern Arkansas and proceeding downstream to Table Rock Lake, Lake Taneycomo, and

Bull Shoals Lake. Norfork Lake is on a tributary of

the White River downstream of Bull Shoals Lake.

With the completion of the Powersite Dam on the

White River in 1912, Lake Taneycomo became the

first major impoundment for hydroelectric power

production in Missouri (U.S. ACE 1967). The areas

near these lakes in both Arkansas and Missouri are

increasingly popular recreational attractions and

retirement havens.

Major tributaries of the White River in Arkansas are

War Eagle Creek, Kings River, Crooked Creek, and

Buffalo and Little Red Rivers. Congress designated the

Buffalo River as the Buffalo National River in 1972

(Public Law 92-237) “for the purposes of conserving

and interpreting an area containing unique scenic and

scientific features, and preserving [it] as a free-flowing

stream” (Mott 1991). Headwaters of War Eagle Creek,

Kings River, and Buffalo River are in the Boston

Mountains, but most of the tributaries of the upper

White River lie within either the Springfield Plateau

(War Eagle Creek) or the Springfield Plateau and Salem

Plateau (Kings River and Buffalo River). Crooked

Creek lies mainly in the Salem Plateau, but its headwaters are in the Springfield Plateau. Land use in this part

of the Upper White River Basin is primarily forest

intermingled with pasture and some cropland.

The James and North Fork White Rivers are major

tributaries of the White River in Missouri. Most of the

James watershed lies within the Springfield Plateau,

with the exception of the lower part of the basin where

the James River or its tributaries have cut into rocks of

Ordovician age in the Salem Plateau. The lower part of

the James watershed is primarily forested, whereas the

upper part is predominately pasture and row-crop

agriculture. Springfield, MO, the largest urban area in

the Ozark Plateaus, lies within the James watershed.

The North Fork White watershed, about 70 percent

forested, lies entirely in the Salem Plateau. The lower

part of the North Fork of the White River has been

impounded (dammed) to form Norfork Lake.

Neosho-Illinois River Basin

The Neosho River originates in east-central Kansas

in the gently rolling hills of the Osage Plains (fig. 1.4).

The river flows southeast through Kansas into Oklahoma. Below the confluence with the Spring River, a

major tributary, the Neosho River follows a winding

course through a chain of reservoirs before entering the

Arkansas River. These reservoirs are popular recreational attractions. The lower part of the drainage,

predominantly located in Missouri and Oklahoma, lies in

the Springfield Plateau. The total drainage area of the

7
Table 1.2— Drainage area and national forest lands of aquatic study area watersheds

River basin Watershed Drainage Ozark National Mark Twain Ouachita National National forests

Watershed name code (HUC) area Forest National Forest Forest combined

Acres Acres % Acres % Acres % Acres %

Osage River Basin

H.S. Truman Reservoir 10290105 774,922 0 0 0 0 0 0 0 0

Sac 10290106 1,261,757 0 0 0 0 0 0 0 0

Pomme de Terre 10290107 542,814 0 0 0 0 0 0 0 0

South Grand 10290108 1,310,460 0 0 0 0 0 0 0 0

Lake of the Ozarks 10290109 886,625 0 0 0 0 0 0 0 0

Niangua 10290110 660,126 0 0 0 0 0 0 0 0

Lower Osage 10290111 689,175 0 0 0 0 0 0 0 0

Gasconade River Basin

Upper Gasconade 10290201 1,144,116 0 0 71,843 6 0 0 71,843 6

Big Piney 10290202 483,524 0 0 89,103 18 0 0 89,103 18

Lower Gasconade 10290203 662,392 0 0 34,214 5 0 0 34,214 5

Meramec River Basin

Meramec 07140102 1,382,471 0 0 174,681 13 0 0 174,681 13

Bourbeuse 07140103 535,812 0 0 0 0 0 0 0 0

Big 07140104 615,790 0 0 33,606 5 0 0 33,606 5

Upper St. Francis River Basin

Upper St. Francis 08020202 830,606 0 0 111,363 13 0 0 111,363 13

Neosho-Illinois River Basin

Lake O’ the Cherokees 11070206 588,927 0 0 0 0 0 0 0 0

Spring 11070207 1,649,846 0 0 0 0 0 0 0 0

Elk 11070208 659,861 0 0 0 0 0 0 0 0

Lower Neosho 11070209 1,414,516 0 0 0 0 0 0 0 0

Illinois 11110103 1,056,531 15,708 1 0 0 0 0 15,708 1

Arkansas River Basin

Dirty-Greenleaf 11110102 505,247 0 0 0 0 0 0 0 0

Robert S. Kerr Reservoir 11110104 1,156,317 48,096 4 0 0 0 0 48,096 4

Poteau 11110105 1,218,490 0 0 0 0 221,213 18 221,213 18

Frog-Mulberry 11110201 805,450 230,175 29 0 0 0 0 230,175 29

Dardanelle Reservoir 11110202 1,190,733 413,769 35 0 0 0 0 413,769 35

Conway- Pt. Remove 11110203 727,472 34,365 5 0 0 0 0 34,365 5

Petit Jean 11110204 697,467 47,493 7 0 0 161,851 23 209,344 30

Cadron 11110205 492,361 0 0 0 0 0 0 0 0

Fourche La Fave 11110206 716,215 0 0 0 0 372,258 52 372,258 52

Lower Ark-Maumelle 11110207 708,178 0 0 0 0 17,589 2 17,589 2

Kiamichi-Little River Basin

Kiamichi 11140105 1,165,716 0 0 0 0 77,798 7 77,798 7

Upper Little 11140107 901,946 0 0 0 0 4,880 1 4,880 1

Mountain Fork 11140108 547,634 0 0 0 0 64,756 12 64,756 12

Lower Little 11140109 1,263,915 0 0 0 0 69,609 6 69,609 6

Ouachita-Saline River Basin

Ouachita Headwaters 08040101 989,322 0 0 0 0 453,041 46 453,041 46

Upper Ouachita 08040102 1,127,469 0 0 0 0 76,573 7 76,573 7

Little Missouri 08040103 1,342,083 0 0 0 0 41,313 3 41,313 3

Upper Saline 08040203 1,094,040 0 0 0 0 47,988 4 47,988 4

Upper White River Basin

Beaver Reservoir 11010001 1,635,563 43,303 3 44,237 3 0 0 87,539 5

James 11010002 926,610 0 0 21,533 2 0 0 21,533 2

Bull Shoals Lake 11010003 1,664,274 0 0 141,472 9 0 0 141,472 9

(continued)

8
Table 1.2— Drainage area and national forest lands of aquatic study area watersheds (continued)

River basin Watershed Drainage Ozark National Mark Twain Ouachita National National forests

Watershed name code (HUC) area Forest National Forest Forest combined

Acres Acres % Acres % Acres % Acres %

Upper White River Basin (continued)

Middle White 11010004 943,605 107,945 11 0 0 0 0 107,945 11

Buffalo 11010005 858,950 174,844 20 0 0 0 0 174,844 20

North Fork White 11010006 1,174,854 0 0 102,069 9 0 0 102,069 9

Little Red 11010014 1,165,347 12,323 1 0 0 0 0 12,323 1

Upper Black River Basin

Upper Black 11010007 1,222,551 0 0 225,507 18 0 0 225,507 18

Current 11010008 1,679,700 0 0 239,375 14 0 0 239,375 14

Lower Black 11010009 499,089 0 0 11,794 2 0 0 11,794 2

Spring 11010010 779,026 0 0 0 0 0 0 0 0

Eleven Point 11010011 769,055 0 0 140,600 18 0 0 140,600 18

Strawberry 11010012 505,236 0 0 0 0 0 0 0 0

Total 47,624,186 1,128,021 116 1,441,397 135 1,608,869 181 4,178,286

HUC = hydrologic unit code.

Arkansas

Missouri

James

(11010002)

Bull Shoals Lake

 

(11010003)

North Fork White

(11010006)

Middle White

(11010004)

Buffalo

(11010005)

Little Red

(11010014)

Beaver Reservoir

(11010001)

River basin boundary

Watersheds

Tributaries

Buffalo

River

Kings

White

River

River

Crooked Creek

White

River

White River

North

Fork

James

River

Little Red

River

Beaver Reservoir

(11010001)

Watershed name and

(hydrologic unit code)

Figure 1.3—Watersheds of the Upper White River Basin with major tributaries and reservoirs.

9
Oklahoma

Arkansas

Missouri

Spring

(11070207)

Illinois

(11110103)

Elk

(11070208)

Lake O'

the

Cherokees

(11070200)

)

Lower Neosho

(11070209)

Spring

River

Elk

Illinois

River

River

Watersheds

Tributaries

Lower Neosho

(11070209)

River basin boundary

Watershed name and

(hydrologic unit code)

Neosho

River

Figure 1.4—Watersheds of the Neosho-Illinois River Basin with major tributaries and reservoirs.

Neosho River is about 12,500 mi2, of which about 6,200

mi2

 is in the aquatic study area. The Elk River, a major

tributary of the Neosho River, lies entirely in the Springfield Plateau and drains pasture and forestland in

northern Arkansas and southwestern Missouri. Land in

the upper part of the basin within the aquatic study area

is used principally for cropland and pasture, although

coal and lead-zinc mining have occurred in the upper

part of the basin. The largest urban area in this part of

the Neosho-Illinois River Basin is Joplin, MO.

The Illinois River originates in northwestern Arkansas and flows generally northward to Oklahoma. In

Oklahoma, it flows southwest into the Arkansas River

(fig. 1.4). The lower part of the Illinois River is

impounded and forms Tenkiller Ferry Lake. The Illinois

watershed (about 1,600 mi2

) lies entirely within the

aquatic study area, mostly in the Springfield Plateau.

The headwaters of the watershed are in the Boston

Mountains. From the Arkansas-Oklahoma State line

west to the upper end of Tenkiller Ferry Lake, the

Illinois River is a State-designated scenic river.

Osage River Basin

The Osage River originates in east-central Kansas,

where it is called the Marais des Cygnes (Wetland of the

Swans), and flows generally eastward into Missouri (fig.

1.5). The upper two-thirds of the Osage River system—

10
including the Little Osage, Marmaton, and South Grand

Rivers—drains the gently rolling prairie land of the Osage

Plains. The South Grand River is the second largest and

only major south-flowing tributary of the Osage River.

Land use in this part of the basin is primarily cropland and

pasture, although coal mining has occurred along the

western boundary of this portion of the aquatic study area.

The Osage River continues flowing eastward across

the Springfield and Salem Plateaus to its confluence

with the Missouri River. About 602 mi of the river have

been inundated by the construction of four major

reservoirs, including the Harry S. Truman Reservoir

and the Lake of the Ozarks on the river’s main stem

(Duchrow 1984). As in the Upper White and

Neosho-Illinois River Basins, these lakes are popular

recreational attractions and retirement havens. The total

drainage area of the Osage River Basin is 15,300 mi2

,

with 10,700 mi2

 in Missouri and the remainder in

Kansas. The portion of the Osage River drainage that

lies in the aquatic study area is about 9,600 mi2

.

The Sac River is the only tributary of the Osage

River that lies entirely within the Springfield Plateau.

Stockton Lake, the third major reservoir in the Osage

River Basin, is on the Sac River. About one-half of the

Sac watershed is forested, with the remaining land

primarily in cropland or pasture; a small part of the basin

Missouri

Kansas

Oklahoma

South Grand

 

(10290108)

Harry S.

Truman

Reservoir

(10290105)

Sac

(10290106)

Niangua

(10290110)

Pomme

de Terre

Terre 

(10290107)

Lower

Osage

(10290111) )

Lake of

the Ozarks

(10290109)

Osage

River

Niangua

River

River

Osage River

Sac

River

Pom

de

me

Sac

(10290106)

River basin boundary

Watersheds

Tributaries

Watershed name and

(hydrologic unit code)

Figure 1.5—Watersheds of the Osage River Basin with major tributaries and reservoirs.

11
Lower

Gasconade

(10290203)

Big Piney

 (10290202)

Upper

(10290201)

Gasconade

Big

Piney

River

Gasconade

River

Osage

Fork

Gasconade

Big Piney River

(10290202)

River basin boundary

Watersheds

Tributaries

Watershed name and

(hydrologic unit code)

Figure 1.6—Watersheds of the Gasconade River Basin

with major tributaries.

is urbanized. Withdrawals from two small lakes and a

spring in the Sac watershed supply much of the drinking

water for Springfield, MO, which lies near the drainage

divide of the Sac River Basin.

The Pomme de Terre and Niangua Rivers are the

two main Osage River tributaries that lie entirely within

the Salem Plateau. Pomme de Terre Lake on the lower

Pomme de Terre River is the fourth major reservoir in

the Osage River Basin. The resident and tourist populations are not as large at Pomme de Terre Lake as at

some of the other reservoirs in the aquatic study area.

Nearly 50 percent of land use in both basins is agricultural, with activity centered primarily around livestock

production.

Gasconade River Basin

The Gasconade River and its major tributary, the Big

Piney River of Missouri, generally flow northeast

through the rough terrain of the Salem Plateau to the

Missouri River (fig. 1.6). No major reservoirs or urban

areas of any size are located in the Gasconade River

Basin, which lies entirely within the aquatic study area.

The total drainage area of the Gasconade River Basin is

3,600 mi2

. At one time, parts of the Gasconade and Big

Piney Rivers were considered for inclusion in the Wild

and Scenic River System. However, because of existing

shoreline development, agricultural activities, and

transportation corridors, some segments of the two

rivers did not meet the eligibility criteria (U.S. BOR

1973). The basin is about 75 percent forested; however,

livestock and crop production are important land uses in

the basin, particularly in the stream valleys.

Meramec River Basin

The Meramec River Basin originates in the Salem

Plateau in the northeastern part of the aquatic study

area and flows northeast to the Mississippi River just

south of St. Louis (fig. 1.7). Meramec Spring, the

seventh largest spring in Missouri, more than doubles

the flow of the Meramec River in the upper part of the

basin. Most of the basin (3,960 mi2

) is in the Assessment area, with the exception of a small part in the St.

Louis metropolitan area. The upper part of the basin is

primarily forested but has some cropland and pasture.

Small tributaries of the upper Meramec River drain part

of Missouri’s Viburnum Trend mining area.

The Meramec River has two major tributaries, the

Bourbeuse River on the north and the Big River on the

east. Much of the Bourbeuse watershed, which flows

from west to east along the northern part of the

Meramec River Basin, is underlain by undifferentiated

deposits of Pennsylvanian age. These Pennsylvanian

strata overlie and sometimes fill depressions in an

ancient karst topography that developed in deposits of

Ordovician age (Vineyard and others 1974). The area’s

gently rolling terrain is suitable for agricultural land uses,

and the Bourbeuse River Basin has more pasture and

tilled lands than other parts of the Meramec River

Basin. The Big River originates in the St. Francois

Mountains and flows northward through the Salem

12
Plateau to the Meramec River. The Big River Basin

encompasses much of the Old Lead Belt mining area

and most of the area of past and present barite mining

in Missouri.

Upper St. Francis River Basin

The St. Francis River originates on the southern flank

of the rugged St. Francois Mountains of southeastern

Missouri and flows south through the Salem Plateau and

out of the aquatic study area (fig. 1.8). The total

drainage area of the basin is about 6,480 mi2

, with about

1,310 mi2

 within the aquatic study area. Lake

Wappapello, located at the southeastern extent of the

basin in the study area, is a major recreational area.

Like other basins in the Salem Plateau, the St. Francis

River Basin is predominantly forested with some

pasture. Some lead and zinc mining has occurred in the

upper part of the basin.

Missouri

Meramec

Big

(07140104)

Bourbeuse

(07140103)

Bourbeuse

River

River

Meramec

Big

River

(07140102)

Meramec

(07140102)

River basin boundary

Watersheds

Tributaries

Watershed name and

(hydrologic unit code)

Figure 1.7—Watersheds of the Meramec River Basin with major tributaries.

13
Upper St. Francis

(08020202)

St.

Francis

River

Upper St. Francis

(08020202)

River basin boundary

Watersheds

Tributaries

Watershed name and

(hydrologic unit code)

Figure 1.8—Upper St. Francis River Basin with major tributaries and reservoir.

Upper Black River Basin

The Black River is the largest tributary of the White

River system with a drainage area of 8,560 mi2

. Major

tributaries of the Black River include the Current,

Spring, Eleven Point, and Strawberry Rivers. The

Strawberry River Basin lies wholly in north-central

Arkansas, but the headwaters and much of the drainage

areas of the other major tributaries of the Black River

are in southern Missouri. Like the St. Francis River, the

Black River originates on the southern flank of the St.

Francois Mountains and flows southward through the

Salem Plateau into Arkansas (fig. 1.9). On the eastern

side of the Black River, a small part of the drainage

area is in the Mississippi Alluvial Plain. The river’s

other tributaries lie entirely in the Salem Plateau. The

only major reservoir in the basin, Clearwater Lake, is on

the Black River in Missouri. At least 50 percent of the

land is forested in all of the basin’s drainages, with the

remainder used primarily for pasture and cropland. No

major urban areas exist in this basin. Small tributaries of

the upper Black River drain the southern end of

Missouri’s Viburnum Trend mining area.

The Upper Black River Basin is characterized by

rugged, hilly countryside and numerous springs, many of

which are clear and fast flowing. The three largest

springs in the Assessment area are found in the Upper

Black River Basin: (1) Greer Spring (on the Eleven

Point River), with an average flow of 289

ft3

/s, (2) Mammoth Spring (on the Spring River), with

measured flows from 240 to 431 ft3

/s, and (3) Big

Spring (on the Current River), with an average flow of

14
428 ft3

/s (Vineyard and others 1974). In 1974, Congress

designated 134 mi of the Current River and Jacks Fork,

its principal tributary, plus about 65,000 acres of adjoining land in Missouri as Ozark National Scenic

Riverways (Barks 1978). This designation is intended to

help preserve the natural conditions of the Current

watershed and to increase recreational opportunities for

anglers, canoeists, and campers. Similarly, a part of the

Eleven Point River (also in Missouri) has been designated a National Scenic River.

Ouachita Province

Arkansas River Basin

Originating in central Colorado, the Arkansas River

flows generally southeastward through Kansas, Oklahoma, and Arkansas to its confluence with the Mississippi

River. The total drainage area of the Arkansas River is

160,600 mi2

 (Sullavan and Terry 1970). Excluding the

Neosho-Illinois River Basin, about 12,900 mi2

 of Arkansas River drainage area falls within the aquatic study

Arkansas

Missouri

Current

(11010008)

Upper Black

(11010007)

Spring

(11010010)

Eleven Point

(11010011)

Strawberry

(11010012)

1

Lower Black

(1010009)

Jacks

Fork

Current

River

Black

River

Eleven

Point

River

Spring

River

Strawberry

River

Strawberry

(11010012)

River basin boundary

Watersheds

Tributaries

Watershed name and

(hydrologic unit code)

Figure 1.9—Watersheds of the Upper Black River Basin with major tributaries.

15
Oklahoma

Arkansas

Dirty-Greenleaf

f 

(11110102)

1

Poteau

(11110105)

Dardanell Reservoir

(11110202) Frog-Mulberry

(11110201)

Petit Jean

(11110204)

Robert S. Kerr

 

Reservoir

(11110104)

Fourche La Fave

(11110206)

Lower Arkansas

- Maumelle

(11110207)

Lake ConwayPoint Remove

(11110203) Cadron

(11110205)

Poteau River

Arkansas

River

Mulberry

River

Petit Jean River

Illinios

Bayou

Fourche La Fave River

Arkansas

River

Poteau

(11110105)

River basin boundary

Watersheds

Tributaries

Watershed name and

(hydrologic unit code)

Figure 1.10—Watersheds of the Arkansas River Basin with major tributaries and reservoirs.

area (fig. 1.10). The stream reach of the Arkansas River

within the aquatic study area is part of the McClellanKerr Navigation System, which includes a series of 12

locks and dams that extend from Webber Falls Lock and

Dam, southeast of Muskogee, OK—near the western

boundary of the aquatic study area—to Lock and Dam 4,

east of Pine Bluff, AR—near the southeastern boundary

of the study area (U.S. ACE 1976).

The principal tributaries of the Arkansas River

are the Poteau River (1,890 mi2

) in eastern Oklahoma

and western Arkansas; Petit Jean River (1,080 mi2

),

which originates in western Arkansas; and Fourche La

Fave River (1,120 mi2

), which originates in western

Arkansas. The largest urban areas in the Arkansas

River Basin portion of the aquatic study area are Little

Rock and Fort Smith, AR. Land use in the part of the

basin within the Assessment area is primarily dominated

by cropland along the Arkansas River and by forest in

the Highlands of the Boston Mountains (to the north)

and the Ouachita Mountains (to the south). In addition

to pools upstream of locks and dams on the Arkansas

River, the basin includes several large reservoirs: Wister

Lake (on the Poteau River), Nimrod Lake (on the

Fourche La Fave River), Lake Maumelle (on Big

Maumelle Creek) and Blue Mountain Lake (on the Petit

Jean River).

16
Ouachita-Saline River Basin

The Ouachita River originates in the Ouachita

Mountains of western Arkansas and flows southeastward out of the Assessment area to the Red River in

Louisiana. The drainage area of the Ouachita-Saline

River Basin is about 18,900 mi2

, with about 7,100 mi2

located within the aquatic study area (fig. 1.11). The

Little Missouri (2,103 mi2

) and Caddo (477 mi2) Rivers

are principal tributaries. The largest urban area within

the basin is Hot Springs, AR. Land use in the basin is

dominated by forest, with some agriculture. Several

reservoirs on the Ouachita River, including Lake

Ouachita and Lake Hamilton, are popular recreational

attractions.

The Saline River originates in the Ouachita Mountains in the central part of Arkansas and flows south or

southeast to the Ouachita River in southern Arkansas.

The drainage area of the Saline River is 3,250 mi2

, with

about 1,716 mi2

 located in the aquatic study area. The

principal tributary of the Saline River is Hurricane

Creek (312 mi2

). The largest urban area within this part

of the basin is Benton, AR. Lake Winona, the only

major reservoir, is on Alum Fork (of the Saline River).

Land use in the upper part of the basin is primarily

forest, but bauxite has been mined near Benton. There

is a pronounced increase in agricultural land use in the

lower portions of the basin, where the river flows

through the West Gulf Coastal Plain.

Little Missouri

(08040103)

Upper Saline

(08040203)

Upper Ouachita

(08040102)

Ouachita Headwaters

(08040101)

Arkansas

Little

Missouri

River

Caddo

River

Saline

River

Ouachita

River

Oklahoma

Upper Ouachita

(08040102)

River basin boundary

Watersheds

Tributaries

Watershed name and

(hydrologic unit code)

Figure 1.11—Watersheds of the Ouachita-Saline River Basin with major tributaries and reservoirs.

17
Kiamichi

(11140105)

Lower Little

(11140109)

Upper Little

(11140107)

Mountain Fork

(11140108)

Oklahoma

Arkansas

Kiamichi

River

Little

River

Glover

River Mountain Fork River

Little

River

Lower Little

(11140109)

River basin boundary

Watersheds

Tributaries

Watershed name and

(hydrologic unit code)

Texas

Figure 1.12—Watersheds of the Kiamichi-Little River Basin with major tributaries and reservoirs.

Kiamichi-Little River Basin

The Kiamichi River originates in the Kiamichi

Mountains of southeastern Oklahoma. It flows westward through the mountains, then in a southerly direction to its confluence with the Red River, which forms

the northern boundaries between Texas and Oklahoma

and between Texas and Arkansas (fig. 1.12). The

drainage area of the Kiamichi River, located entirely

within the aquatic study area, is about 1,800 mi2

. The

principal tributaries of the Kiamichi River are Ten Mile

(204 mi2

) and Cedar Creeks (176 mi2). No large urban

areas are located in the Kiamichi-Little River Basin.

Sardis Lake on Jackfork Creek and Hugo Lake on the

Kiamichi River are the major reservoirs in this part of

the basin. The Kiamichi-Little River Basin is primarily

forested.

The Little River also originates in the Kiamichi

Mountains of southeastern Oklahoma (fig. 1.12) and

flows westward through the mountains, then generally to

the southeast to its confluence with the Red River in

southwestern Arkansas. The drainage area of the Little

River, located entirely within the aquatic study area, is

about 4,200 mi2

. The principal tributaries are the Mountain Fork (865 mi2

) and Cossatot (541 mi2) Rivers. No

large urban areas are located in this basin. Millwood Lake

on the Little River and Broken Bow Lake on the Mountain Fork are the major reservoirs in this part of the basin.

18
Major Lakes

More than 30 major Federal reservoirs are located

within the aquatic study area. These reservoirs, each

typically covering many thousand acres, serve many

purposes, including flood control, hydroelectric power

generation, water supply, and/or navigation. A second

cluster of lakes includes medium- to small-sized ones

built for municipal water supplies, recreational fishing

and boating, and/or small watershed flood control. A

third group of lakes, more appropriately called ponds,

includes even smaller water bodies (often privately

owned) built for recreation and/or livestock purposes.

Table 1.3 displays the number and total acres of

lakes and ponds by watershed within each major river

basin in the aquatic study area. This table was developed from the U.S. Environmental Protection Agency’s

(EPA’s) River File version 3 (RF3) data base. While this

data base includes water bodies as small as one-fourth

acre, it does not include every water body of this size or

smaller. Therefore, it is likely that large numbers of the

smallest water bodies are not represented. However,

while the number of lakes and ponds might easily be

doubled, tripled, or more if the data base included all

lakes and ponds, acreage totals would not increase

significantly. The statistical influence of the larger lakes

on the acreage totals in table 1.3 overwhelms whatever

acres of small lakes and ponds were missed.

Because sources and methods of measurement often

vary between data bases, the acreage of any given lake

may differ from data base to data base. For example,

one data base may show that a reservoir has several

hundred acres more than another one shows, when the

only real difference is that islands were included in the

first measurement and excluded in the second. Reservoir acreage might also vary between data bases if the

data were taken from a topographic map based on lake

water elevation or from aerial photographs or satellite

imagery of actual lake water surface area. A variance

between data bases of 10 percent or more might be

expected for the surface area figures.

Ground Water

Ground water is an abundant resource in most of the

Ozark Plateaus Province. Multiple aquifers exist that

can supply water to meet domestic, community, and

commercial needs throughout this portion of the Assessment area. In many parts of the Ozark Plateaus, a

specific site will often intersect with viable aquifers at

multiple horizons. Yields from wells are commonly

measured in 10’s and 100’s of gallons per minute

(gal/min) and occasionally, more than 1,000 gal/min for

some aquifers.

Within the Ouachita Province, ground water is more

limited. Few large-volume users (communities, industries) rely on the area’s supply of ground water. While

ground water can be obtained almost everywhere in the

Ouachitas, yields or “yield rates” are often low, with

most wells yielding less than 50 gal/min. Wells providing

more than 100 gal/min are rare, and wells supplying less

than 10 gal/min are the norm (Albin 1965).

Table 1.3—Number and acres of lakes and ponds in the aquatic study area, by major river basins

River basin All impoundments Lakes > 1,000 acres Lakes 10–1,000 acres Ponds < 10 acres

Number Acres Number Acres Number Acres Number Acres

Osage 1,243 158,108 9 140,586 399 13,397 835 4,126

Gasconade 213 5,474 0 0 92 4,902 121 572

Meramec 436 6,484 0 0 152 4,940 284 1,545

Upper St. Francis 134 3,068 0 0 44 2,575 90 493

Neosho-Illinois 1,035 101,478 13 69,802 335 28,252 687 3,424

Arkansas 3,061 212,254 20 150,698 896 52,999 2,145 8,557

Kiamichi-Little 779 84,728 9 65,454 242 17,354 528 1,919

Ouachita-Saline 560 81,360 6 65,382 239 13,954 315 2,024

Upper White 512 176,279 12 163,899 175 10,899 325 1,480

Upper Black 413 17,569 3 7,999 190 8,449 220 1,120

Total 8,386 846,803 72 663,821 2,764 157,722 5,550 25,260

19
Ground Water in the Ozark Plateaus Province

Ground water divides (places where the flow of

ground water changes direction markedly) in the shallow

aquifers of the Ozark Plateaus generally coincide with

topographic divides. Water table surfaces can be

visualized as a subdued reflection of topography.

Altitudes of ground water levels are highest in the

Boston Mountains and along the major topographic ridge

extending across southern Missouri, which form regional

ground water divides. Ground water flows away from

these regional divides; water flowing in the deep part of

the ground water system discharges into the major rivers

of the area (fig. 1.13). Ground water moving through the

shallow part of the ground water system follows short

Kansas

Missouri

Arkansas

Osage

River

River

Mississippi

Meramec

River

Black

River

River St. Francis

White

River

Neosho

River

Illinois River

Oklahoma

River

Gasconade

River

Figure 1.13—Directions of the flow of ground water in the Ozark Plateaus Province (modified from Adamski

and others 1995). (The St. Francois Mountains are represented by the medium gray area on the eastern edge

of the Ozark Highlands, the Springfield Plateau by the medium gray area in the western half of the Ozark

Highlands and encompassing the words “Illinois River.”)

Osage Plains

Boston Mountains

Springfield Plateau

Salem Plateau

St. Francois Mountains

Mississippi Alluvial Plain Generalized direction of

 regional ground water

 flow

Ground water divide

River basin boundary

National Water-Quality

 Assessment study unit

 boundary

20
(usually less than 10 mi), local flow patterns that terminate at nearby streams (Imes and Emmett 1994).

Regional boundaries for the ground water flow

system in the Ozark Plateaus and adjacent areas include

the Missouri and Mississippi Rivers to the north and

northeast, respectively. To the southeast, ground water

discharges into the unconsolidated sedimentary strata

of the Mississippi Alluvial Plain. The topographic divide

along the crest of the Boston Mountains forms the

southern boundary. The western boundary is formed by

a broad, topographically low area where westwardflowing fresh water mixes with eastward-flowing saline

water along a transition zone between regional flow

systems (Imes and Emmett 1994).

The ground water system in the Ozark Plateaus can

be divided into seven major hydrogeologic units based

on relative rock permeabilities and yields from wells.

These hydrogeologic units consist of three main aquifers

and four confining units that coincide with the province’s

major geologic units and physiographic sections (fig.

1.14). (A confining unit is composed of relatively

impervious layers of rock that separate it from other

aquifers.) These units include the Western Interior

Plains confining system, the Springfield Plateau aquifer,

B

B

C

C

C

C C

B

B

B

B

A

A

E

E

D

D

D

D

C

C

C

Missouri

Arkansas

Kansas

Oklahoma

F

Figure 1.14—Locations of hydrogeologic units in the Ozark Plateaus (modified from Adamski and

others 1995).

Unconsolidated sediments

 (Mississippi Alluvial Plain)

Western Interior Plains

 confining system

Springfield Plateau aquifer

Ozark aquifer and confining

 unit

St. Francois aquifer and

 confining unit

Basement confining unit

Hydrogeologic unit

 boundary

National Water-Quality

 Assessment study unit

 boundary

A

B

C

D

E

F

21
the Ozark confining unit, the Ozark aquifer, the St.

Francois confining unit, the St. Francois aquifer, and the

Basement confining unit. The middle five units compose

the Ozark Plateaus aquifer system and are confined

above and below by the Western Interior Plains confining system and the Basement confining unit, respectively (Imes and Emmett 1994). An eighth

hydrogeologic unit is composed of unconsolidated

sedimentary strata in the Mississippi Alluvial Plain, but

the ground water resources of this unit will not be

further discussed in this report because it is mostly

outside the aquatic study area.

Western Interior Plains Confining System

The Western Interior Plains confining system (fig.

1.14) coincides with parts of two physiographic sections—the Boston Mountains section (in the southern

part of the Ozark Plateaus Province) and the Osage

Plains section (west of the Ozark Plateaus Province).

Rock strata of late Mississippian to Pennsylvanian age

form this confining system (Imes and Emmett 1994).

Altitudes at the top of the Western Interior Plains

confining system range from 800 to 1,000 ft above sea

level in the Osage Plains, and from 1,000 to more than

2,000 ft above sea level in the Boston Mountains. The

confining system is from 40 to 800 ft thick in the Osage

Plains, but averages between 1,500 and 2,000 ft thick in

the Boston Mountains (Imes 1990f).

Rock types in this regional confining system include

relatively permeable sandstone and limestone beds

separated by thick layers of impermeable shale that

together result in an overall low permeability. Hydraulic

conductivities (the ability of water to move through

strata of differing permeabilities while under the influence of a hydraulic gradient) generally range from 0.001

to 0.01 ft per day (ft/d) depending upon thickness and

shale content (Imes and Emmett 1994).

Yields of wells in western Missouri range from 1 to

40 gal/min. Specific capacities (well yield per unit of

drawdown) of these wells range from 0.1 to 3 gal/min

per foot (Kleeschulte and others 1985). Yields of 16

wells completed in this confining system in northwestern

Arkansas range from 2.5 to 19 gal/min (Imes and

Emmett 1994).

Springfield Plateau Aquifer

Where The Springfield Plateau aquifer is unconfined,

it coincides with the Springfield Plateau (fig. 1.14). The

aquifer consists of limestones and cherty limestones of

Mississippian age and is about 100 to 200 ft thick in

most places (but can be more than 400 ft thick in

southwestern Missouri). The rock strata lie flat, but

regionally, they dip gently to the west and south. The

rocks are often fractured and faulted. The Springfield

Plateau aquifer is unconfined over most of the Springfield Plateau, but the Western Interior Plains confining

system, which primarily is composed of shales of

Pennsylvanian age, confines the aquifer in the Osage

Plains and Boston Mountain sections. The Springfield

Plateau aquifer is separated from the underlying Ozark

aquifer by the Ozark confining unit, which consists

primarily of black shale of Devonian age (Imes and

Emmett 1994).

Altitudes at the top of the Springfield Plateau aquifer

range from about 200 to 1,600 ft above sea level where

the aquifer crops out and is unconfined. The dip of the

beds generally is about 11 ft/mi. Thickness of the

aquifer ranges from about 100 ft in south-central

Missouri to about 400 ft in southeastern Kansas (Imes

1990e).

Altitudes of the potentiometric surface (the surface

to which water can rise by hydrostatic pressure) of the

Springfield Plateau aquifer range from more than 1,400

ft in the eastern part of the aquatic study area to less

than 700 ft near the western boundary of the study

area. Regionally, ground water flows from topographic

divides and discharges into seeps and springs and then

to major streams (fig. 1.13). Locally, the ground water

can flow across topographic divides; hence, precise

determination of contributing areas for wells and

recharge basins for springs can be arduous (Adamski

and others 1995).

Fracturing and dissolution of the limestone units in the

Springfield Plateau result in karst features, such as

sinkholes and caves. Karst features and springs are

more abundant in the nonchert-bearing limestones, such

as the St. Joe Member of the Boone Formation, than in

the chert-bearing limestones.

Wells drilled into the Springfield Plateau aquifer

generally have yields of less than 20 gal/min. Most wells

22
are used primarily for domestic water supply and for

watering livestock. However, several industrial wells

completed in the aquifer in southwestern Missouri yield

300 to 400 gal/min (Imes and Emmett 1994).

Ozark Confining Unit

The Ozark confining unit (fig. 1.14) consists of rocks

of Devonian and Mississippian age from the

Chattanooga Shale through the Northview Shales and

Chouteau Limestone. This confining unit consists mostly

of shales and dense limestones that crop out along the

Eureka Springs Escarpment in southwestern Missouri

and northwestern Arkansas and underlie much of the

Springfield Plateau aquifer. The Ozark confining unit

averages about 60 to 80 ft thick but locally is 120 ft

thick in southeastern Kansas (Imes 1990d).

Shales and dense limestones in the Ozark confining

unit hydraulically separate the overlying Springfield

Plateau aquifer from the underlying Ozark aquifer.

Shale content ranges from about 10 to 100 percent in

northwestern Arkansas. Shale is missing from the unit in

parts of southwestern Missouri, northeastern Oklahoma,

and southeastern Kansas (Imes 1990d). Differences in

water levels of about 50 ft between the Springfield

Plateau and Ozark aquifers indicate that, even where

the shale is missing, the low vertical permeability of the

aquifers’ dense limestones effectively separates the two

hydrogeologic units (Imes and Emmett 1994).

Ozark Aquifer

The Ozark aquifer, which consists of a thick sequence

of dolomites, sandstones, limestones, and shales, crops

out in the Salem Plateau in south-central Missouri and

northern Arkansas (fig. 1.14). The highest altitude of

the top of the aquifer is about 1,500 ft above sea level in

south-central Missouri. Altitudes then decrease to 300 ft

above sea level near the eastern boundary of the Ozark

Plateaus to about sea level near the western boundary

and finally to nearly 2,000 ft below sea level near the

southern boundary (Imes 1990c).

Aquifer thickness ranges from about 300 ft in

northeastern Oklahoma to nearly 4,000 ft in northern

Arkansas. However, aquifer thickness averages between 1,500 and 2,000 ft throughout much of the Ozark

Plateaus (Imes 1990c).

The configuration of the potentiometric surface of

the unconfined Ozark aquifer generally mirrors the

overlying topography. Levels of ground water in the

wells drilled in this aquifer average about 700 to 1,000 ft

above sea level over much of the Salem Plateau but are

as high as 1,400 ft above sea level in south-central

Missouri (Imes 1990c). Precipitation recharges the

unconfined Ozark aquifer nearly everywhere. Ground

water flows mostly laterally from the higher altitudes to

points of discharge in springs and seeps along streams.

The confined part of the Ozark aquifer is recharged by

a lateral flow of ground water from the aquifer’s

unconfined area, and, in places, by seepage from the

overlying Ozark confining unit (Imes and Emmett 1994).

Losing streams, sources of recharge to the ground

water system, are common in some drainage areas

overlying the Ozark aquifer. Results from dye-tracing

studies of ground water indicate that water recharging

the aquifer from the losing streams can discharge in

springs in adjacent drainage basins. This is possible

because, on a local scale, ground water divides do not

always coincide with surface water divides (Harvey and

others 1983).

St. Francois Confining Unit

The St. Francois confining unit hydraulically separates the Ozark aquifer from the underlying St.

Francois aquifer. This confining unit consists of shales,

siltstones, and dolomites of Late Cambrian age, which

crop out around the St. Francois Mountains and dip

radially away from the outcrop area. Maximum shale

content in this part of the Assessment area is about 30

percent (Imes 1990b). In places where shale is thin or

absent, impermeable siltstones and dolomites confine

the St. Francois aquifer (Imes and Emmett 1994). The

maximum thickness of the confining unit is about 750 ft

in parts of Missouri and northern Arkansas. This

confining unit is absent in parts of northwestern Arkansas, west-central Missouri, and northeastern Oklahoma

(Imes 1990b).

St. Francois Aquifer

The St. Francois aquifer (fig. 1.14) consists of the

Lamotte and Reagan Sandstones and the Bonneterre

Dolomite of Late Cambrian age, which crop out in the

23
St. Francois Mountains. These units are used as a

ground water resource where they are unconfined but

are rarely used where overlain by the thicker Ozark

aquifer. Thickness of the St. Francois aquifer is as high

as 900 ft in Missouri and as high as 500 ft in northern

Arkansas. Yields of wells from this aquifer commonly

range from 100 to 500 gal/min (Imes 1990a).

Permeability is primary in the aquifer’s loosely

cemented sandstones, but is due mostly to secondary

porosity in the dolomites as a result of fracturing and

dissolutioning. Permeability data are sparse because the

aquifer is rarely used, but the few available data indicate

that horizontal hydraulic conductivity ranges from 0.1 to

8.6 ft/d. Transmissivity (the ability of an aquifer to

transmit water) ranges from 8.6 to 860 square feet per

day (ft2

/d) (Imes and Emmett 1994).

Basement Confining Unit

The Basement confining unit consists mostly of

igneous rocks of Pre-Cambrian age, which underlie the

Ozark Plateaus and crop out in the core of the St.

Francois Mountains (fig. 1.14). These rocks supply

some water locally where they crop out. The igneous

rocks are relatively impermeable; however, some

secondary permeability is generated from fractures in

the rocks. Yields of wells completed in this confining

unit are as large as 70 gal/min but generally are less

than 10 gal/min (Imes and Emmett 1994).

Ground Water in the Ouachita Province

Ground water divides in the shallow aquifers of the

Ouachita Province generally coincide with topographic

divides; water table surfaces roughly conform to the

topography in the plateaus. Deeper ground water in the

confined sections of the system is strongly influenced by

the complex structure of the area (Bedinger and others

1979). Altitudes of ground water levels are highest in

the mountains of the central Ouachita Mountains, which

form a regional divide. Ground water flows away from

the regional divide, and water flowing in the deep part of

the aquifer system discharges into the major rivers of

the Assessment area. Ground water moving through the

shallow part of the aquifer system follows short (usually

less than 10 mi) flow paths that can be expected to end

with discharge into nearby streams.

Regional boundaries for the flow of ground water in

the Ouachita Mountains include the topographic divide

along the crest of the Boston Mountains to the north and

the Red River to the south. To the east, ground water

discharges into the unconsolidated sediments of the

Mississippi Alluvial Plain.

The ground water system of the Arkansas Valley

physiographic section is similar to that of the Ozark

Plateaus Province to the north. In the Arkansas Valley,

some of the same formations are seen at the surface or

in the subsurface strata, although at greater depths. The

system exhibits the same lithologies (types of rock) and

similar hydraulic characteristics as that of the Ozark

Plateaus.

The ground water system of the Ouachita Mountains

section is not formally divided into hydrogeologic units

because of the extreme heterogeneity observed in rock

permeability and well yield throughout the physiographic

area. Rock formations of the Ouachita Mountains

include, in order of abundance, shale, sandstone, novaculite, chert, conglomerate, and limestone. Many of the

rocks comprising the hydrogeologic framework of the

Ouachita Mountains originally had primary porosity

sufficient to render excellent aquifers. However,

changes in the rock fabric have decreased original

porosity below levels needed for good aquifers. Existing

porosity is predominantly secondary, created by mechanical fracturing of the rocks. Fractures, fault traces,

joints, and bedding plane joints compose much of the

porosity. Thus, minimum baseline porosities observed for

all rock types in the province are quite similar, converging on very low values. The principle differences in the

water-bearing and transmitting capacity of the rocks is

the behavior of fractures in specific rock types, that is,

since the time of compressive stress, some fractures

have been preserved or enlarged by fluid flow while

other fractures have sealed. Therefore, brittle rocks

often provide the best aquifers in the Ouachita Mountains, and fractured sequences of differing rock types—

sandstones, as well as typically poor aquifer rocks such

as cherts, novaculite, and even shale—will also provide

water. Areas with limited quantities of ground water are

ubiquitous in the Ouachita Mountains because the entire

belt has experienced the compression responsible for

mountain building and fracturing, thus secondary

fracture porosity has developed in all rocks. The Bigfork

24
Chert is the only formation in the Ouachita Mountains

that is an aquifer throughout its area of occurrence.

Most wells completed in the Ouachita Mountains are

less than 200 ft deep, though some wells with large

yields are completed to depths between 400 and 600 ft.

Aquifer tests at 10 locations across the area show that

transmissivity generally is less than 135 ft2

/d and is often

less than 6.7 ft2

/d. Specific capacities range from 0.013

to 0.13 ft2

/min after 90 minutes of pumping (Albin 1965,

Halberg and others 1968, Cordova 1963).

Climate

The Ozark-Ouachita Highlands region in Missouri,

Arkansas, and Oklahoma is characterized by a temperate climate due to its mid-latitude location in the interior

of the North American continent. Air masses that move

across the Assessment area generally originate from the

Eastern Pacific Ocean, Western United States, the Gulf

of Mexico, and Canada. The sources of moisture for the

region are the Pacific Ocean and the Gulf of Mexico.

Because of the general circulation characteristics of the

atmosphere, weather systems generally move from

west to east across the Highlands. The average temperature and precipitation patterns over the region are

the result of these weather systems moving across the

region as well as interactions between topography and

atmosphere that introduce additional temperature and

precipitation variations. For example, mountain induced

lifting of air can affect local levels of precipitation. As

air rises over a mountain, it cools and condenses, thus

enhancing precipitation on the windward side of mountains and producing drier conditions on the leeward side.

This section provides an overview of the monthly

average temperature and precipitation patterns over the

Assessment area using data from the National Climate

Data Center. It also includes a discussion of extreme

temperature, precipitation, and wind (e.g., tornado)

events (using data obtained from the National Severe

Storms Laboratory), which are particularly important

atmospheric disturbance factors that impact the region’s

natural resources and human population. The patterns of

monthly average temperatures and precipitation along

with the patterns of extreme temperature, precipitation,

and wind events are discussed in the context of the

region’s topography and seasonal variations in atmospheric circulation (wind and weather patterns).

Monthly Average Maximum Temperature

Patterns

Figure 1.15 shows the average daily maximum

temperatures for the Assessment area for January,

April, July, and October. The months of December,

January, February, and March are characterized by very

large north-to-south variations in maximum temperature.

For example, in January, average maximum temperatures range from about 34 oF in northern Missouri to

about 54 oF in southern Arkansas. Within the Assessment area, the largest spatial variations in maximum

temperature in the winter exist along the ArkansasMissouri border north of the Boston Mountains in

Arkansas and in central Missouri just to the north of the

Ozark Plateaus. These topographic features tend to

inhibit the southward movement of cold air masses from

the Northern United States into the southern sections of

the Assessment area and pool the cold air so that

relatively large temperature gradients can develop in the

vicinity of these topographic features. Very little east-towest variation in monthly average maximum temperatures is observed in winter except for east of the

Ouachita Mountains in Arkansas where warm air tends

to protrude northward. This tongue of slightly higher

temperatures is evident in January but is most significant

in March.

With the onset of the spring months and higher daily

maximum temperatures, the large gradients in monthly

average maximum temperatures begin to diminish. Daily

maximum temperatures in northern Missouri increase

more significantly than temperatures in southern Arkansas, resulting in an overall decrease in the north-to-south

average maximum temperature range from winter to

spring. The maximum temperature range generally

decreases through the spring months. In April, average

maximum temperatures range from about 64 oF in

northern Missouri to about 76 oF in southern Arkansas

(fig. 1.15). By June, average maximum temperatures

range from about 83 oF in northern Missouri to near 90

oF in southeastern Arkansas. Even though the north-tosouth temperature variations are smaller in the spring

than in the winter, the most significant variations

25
Figure 1.15—Average daily maximum temperatures (°F) during January, April, July, and October for the region

within and surrounding the Ozark-Ouachita Highlands Assessment area.

26
throughout the spring still occur mainly along the

Missouri-Arkansas border. As in the winter months,

east-to-west variations in average maximum temperatures across the Assessment area are minimal.

During the summer, very warm conditions usually

develop over the southern Great Plains. Average

maximum daily temperatures exceed 94 oF in eastern

Oklahoma and northeastern Texas in July and August.

The very warm air masses that dominate the southern

Great Plains during the summer also influence maximum

daily temperatures in the western sections of the

Assessment area, resulting in a general southwest-tonortheast temperature gradient over the Highlands, with

average maximum daily temperatures ranging from

about 94 oF in southeastern Oklahoma to about 88 oF in

west-central Illinois in July (fig. 1.15). The terrain

effects on temperature over the Ozark Plateaus are

evident during the summer, with typically lower daily

maximum temperatures occurring over the plateaus and

a significant average maximum temperature gradient

existing near the border area of northeastern Oklahoma,

northwestern Arkansas, and southwestern Missouri.

The elevation variations associated with the Ozark

Plateaus and Ouachita Mountains tend to confine the

warmest air to areas west of the Assessment area

during the summer. With the onset of cooler conditions

in the southern Great Plains in September, the overall

maximum temperature pattern over the Highlands

returns to one that is similar to the late spring pattern.

East-to-west maximum temperature variations decrease

in late summer and early fall, although the Ozark

Plateaus still cause noticeable temperature variations

from northeastern Oklahoma into southwestern Missouri

and northwestern Arkansas.

Through September, October, and November, maximum daily temperatures decrease throughout the

Assessment area. The decreases are more pronounced

in the northern sections of the region than in the southern sections, resulting in significant temperature gradients in the north-south direction like those occurring

during the winter. For example, in September, the

average maximum temperature ranges from about 78 oF

in northern Missouri to about 87 oF in southern Arkansas. However, in November, the average maximum

temperature ranges from about 51 oF in northern

Missouri to about 66 oF in southern Arkansas. The

October average maximum temperature pattern is

shown in fig. 1.15.

Monthly Average Minimum Temperature

Patterns

Average minimum temperature patterns over the

Assessment area exhibit many of the same characteristics as the maximum temperature patterns, although

distinct differences exist. In the winter, most of the

variation in average minimum temperature over the

region is in the north-south direction as it is for the

average maximum temperatures. However, the east-towest temperature variations in Arkansas are also

significant, with average minimum temperatures in the

Mississippi Alluvial Plain about 3 to 4 oF higher than

minimum temperatures in the Ouachita Mountains

region. Figure 1.16 shows the average January minimum temperature pattern over the area that encompasses the Assessment area and suggests the importance of topography and bodies of water in keeping

nocturnal temperatures higher in the Mississippi Alluvial

Plain than in the Ouachita Mountains and Ozark

Plateaus. Very strong northwest-to-southeast gradients

in the average minimum temperature field are observed

from north central Arkansas to southeastern Missouri in

the winter. Average January minimum temperatures

range from about 14 oF in northern Missouri to about 32

oF in southern Arkansas. Average minimum temperatures remain below freezing during December, January,

and February for all of the Assessment area except for

the southernmost counties.

The average minimum temperature patterns over the

Assessment area during the spring months of April, May,

and June are similar to the patterns during the winter

months, with relatively high minimum temperatures

occurring in the Mississippi Alluvial Plain in Arkansas

and relatively low minimum temperatures extending from

the Ouachita Mountains northeastward to eastern

Missouri. Average minimum temperatures for the month

of April are shown in fig. 1.16. The strong northwest-tosoutheast gradient in average minimum temperature is

evident from north central Arkansas to southeastern

Missouri. The lowest minimum temperatures during the

spring months are usually observed over the eastern half

of Missouri. In May, for example, average minimum

27
Figure 1.16—Average daily minimum temperatures (°F) during January, April, July, and October for the region

within and surrounding the Ozark-Ouachita Highlands Assessment area.

28
temperatures are about 51 oF in eastern Missouri

(including much of the Mark Twain National Forest)

compared to average minimum temperatures of about 60

oF in nearby northeastern Arkansas.

The highest minimum temperatures in the Assessment area typically occur during the month of July,

ranging from about 66 oF in parts of eastern and northern Missouri to about 70 oF in the Mississippi Alluvial

Plain in eastern Arkansas and in eastern Oklahoma (fig.

1.16). Through the summer, the spatial pattern of

minimum temperatures in the Assessment area is very

similar to the spring pattern.

The months of October (fig. 1.16), November, and

December bring a return to the wintertime pattern of

average minimum temperatures, when relatively strong

north-to-south gradients dominate the temperature field.

The prominent tongue of low average minimum temperatures extending southward through eastern Missouri in

early fall becomes less prominent later in the fall. The

significant minimum temperature variations in the eastwest direction become less significant as winter approaches, while the average north-to-south minimum

temperature variations increase dramatically. By December, the average minimum temperatures over the region

range from about 20 oF in northern Missouri to about 35

oF in southern Arkansas. This typical minimum temperature range is much greater than the summertime range in

minimum temperatures of about 6 to 8 oF over the same

region. Diurnal (day/night) variations are much more

significant during the late fall and winter than during the

summer because the atmospheric moisture content is

much less when the air is cold. Atmospheric moisture

tends to moderate diurnal temperature fluctuations.

Extreme Maximum Temperature Occurrences

Average monthly or seasonal temperature variations

help determine what types of vegetation and wildlife

thrive under normal conditions. However, extreme

climatic events can introduce stresses that can affect

the health and productivity of ecosystems. The occurrence of temperature extremes is one type of climatic

disturbance that can affect the region’s natural resources. “Extreme temperature” is defined as an

occurrence of daily maximum or minimum temperature

greater than 20 oF above or below normal for that

particular day. Using this definition, the Aquatic Team

compiled the number of abnormally high and low daily

maximum temperature occurrences during the 1950

through 1993 period for the region encompassing the

Assessment area.

Figure 1.17 shows the total number of days from 1950

through 1993 when the maximum temperature was

observed to be 20 oF above or below normal over and

surrounding the Assessment area. As shown in fig. 1.17,

most days during which maximum temperature exceeds

20 oF above normal happen in east-central Missouri at the

northern edge of the Assessment area. More than 500

extreme maximum temperature events occurred in this

area from 1950 through 1993 (corresponding to about 11

events per year). Fewer than 100 extreme maximum

temperature events occurred over the southern sections

of the Assessment area (corresponding to about 2 events

per year). Figure 1.17 suggests that the probability of

extreme maximum temperature occurrences increases

significantly in the region between northern Arkansas and

central Missouri. Most of these extreme maximum

temperature events happen during the late fall and winter.

Analyses of monthly extreme maximum temperature

events during winter from 1950 through 1993 show that

the number of extreme events in January ranged from

about 40 over the Ouachita Mountains to about 110 over

east-central Missouri north of the Ozark Plateaus (including Boone and Calloway Counties). During the month of

February from 1950 through 1993, the number of events

ranged from about 25 over much of southern Arkansas to

85 over the same east-central area in Missouri. In March,

the events ranged from about 15 to 110.

Very few episodes of anomalously (unusually) high

maximum temperatures have occurred over the Assessment area during the months of May through September. Over the entire region, fewer than eight events

occurred during each month between 1950 and 1993. In

July, for example, the largest number of episodes of

anomalously high daily maximum temperatures over the

region was seven in west-central Missouri. It is not until

November that the probabilities of occurrence of

extreme maximum temperature increase significantly.

Figure 1.17 also shows the total number of anomalously low maximum temperature events (daily maximum

temperatures 20 oF or more below normal) that occurred

from 1950 through 1993 over the Assessment area.

Most of these extreme temperature events tend to occur

in central Missouri and eastern Kansas and are least

29
likely to occur in southeastern Missouri and in the far

southwestern section of Arkansas. As with anomalously

high maximum temperature events, the low maximum

temperature events tend to occur during the late fall and

winter. However, for the entire region as a whole, there

is a tendency for more anomalously low maximum

temperature events than high temperature events. Figure

1.17 indicates that more than 500 extreme low maximum

temperature events occurred in central Missouri from

1950 through 1993 (about 11 events per year) while

about 300 events occurred in northeastern Arkansas

over the same period (less than 7 events per year). The

location and month of the highest probability of anomalously low maximum temperature events shifts from

northwestern and western Missouri and eastern Kansas

in January to central Missouri in March and April. From

May until October, extremely low maximum temperature

occurrences, as defined here, are fairly rare (averaging

less than 0.5 events per year).

Extreme Minimum Temperature Occurrences

Using the same definition of “extreme” for determining anomalously high or low minimum temperature

occurrences as that used for maximum temperatures,

the Aquatic Team developed maps (fig. 1.18) of the

total number of occurrences of extreme minimum

temperatures over the Assessment area. Figure 1.18

shows the pattern of anomalously high minimum temperature occurrences over the Assessment area based

on minimum temperature data from 1950 through 1993.

Numerous relative maximums appear over much of the

Assessment area, which is a reflection of the influence

of specific observation sites and the limitations of the

kriging (statistical interpolation method) process in

determining temperatures at locations between observation sites over the region. However, the larger scale

pattern over the region suggests more extreme events

over the western half of Arkansas and the southern half

of Missouri. Fewer extremely high minimum temperature events tend to occur in the Mississippi Alluvial Plain

in Arkansas and north of the Missouri River in Missouri.

Figure 1.17—Total number of occurrences where daily maximum temperatures were 20 °F above normal and 20 °F

below normal in the region within and surrounding the Ozark-Ouachita Highlands Assessment area from 1950

through 1993.

30
As with the extreme maximum temperature events,

most extreme minimum temperature events tend to

occur during the late fall and winter; extremely high

minimum temperatures are most likely to occur in

January. From 1950 through 1993, the number of

extreme minimum temperature episodes in January

ranged from about 90 (average of about 2 events) in the

far southeastern sections of Arkansas to about 40 to 45

(average of about 1 event) in the northern half of

Missouri. Extreme events over the Assessment area are

much less likely from April through the spring, summer,

and early fall. No more than one extreme episode

occurred from 1950 through 1993 at any observation site

in the region during the months of June, July, and August.

The number of extreme cold temperature events over

the Assessment area during the 44 years from 1950

through 1993 is also shown in figure 1.18. There is a

general north-to-south decrease in the number of these

extreme events over the region, with a significant

gradient existing over the Ozark Plateaus. Northern

Missouri experienced about 400 extremely low minimum

temperature events during this 44-year period (about 9

events per year), while the southern half of Arkansas

generally experienced less than 150 events (about 3

events per year). Over the Ozark Plateaus, the number

of extreme events differed by about 100 over a distance

of about 50 to 100 mi. The influence of cold air masses

moving southward from Canada and the northern United

States into the Assessment area is evident in the relatively large number of extreme minimum temperature

events that happen during the winter. Most of the

extremely cold episodes happen in December, January,

and February. For example, from 1950 through 1993,

northern Missouri experienced about 80 to 110 events in

December, about 90 to 110 events in January, and about

70 to 90 events in February. During those same 44 years,

southern Arkansas experienced about 25 to 30, 25 to 40,

and 15 to 20 events in those months, respectively. With

the onset of warmer conditions and higher atmospheric

moisture in the spring, fewer extremely low minimum

temperature episodes occur. Through the late spring,

summer, and early fall, extreme minimum temperature

Figure 1.18—Total number of occurrences where daily minimum temperatures were 20 °F above normal and 20 °F

below normal in the region within and surrounding the Ozark-Ouachita Highlands Assessment area from 1950

through 1993.

31
Figure 1.19—Average yearly precipitation (in

inches) in the region within and surrounding the

Ozark-Ouachita Highlands Assessment area.

episodes are rare over the Assessment area (less than

one episode every 2 years from May to October). In

November, the probability of extreme minimum temperatures increases again under the colder and normally

lower atmospheric moisture conditions of late fall.

Average Monthly Precipitation Patterns

Oceans are the primary sources of atmospheric

moisture that lead to precipitation events over the Earth’s

surface. Evaporation from inland lakes and evapotranspiration (total water loss from soil from direct evaporation

and transpiration of plant moisture) from vegetation can

also contribute to the moisture content of the atmosphere.

Because warm air has a greater capacity for holding

water vapor than cold air, air masses that originate over

the warm tropical zones of oceans are responsible for the

evaporation and transport of more precipitable water

(water that may fall as rain or frozen precipitation) than

air masses originating over the cold sections of oceans

(Hirschboeck 1991). On an annual basis, the precipitable

water vapor content of the atmosphere is greatest over

the Southeastern United States and decreases moving

northward and westward. During the summer, precipitable water contents increase over the entire United

States. In July, average atmospheric precipitable water

vapor content over the Assessment area is about 1.6

inches (in.), compared to average July values of about 1.9

in. and 0.7 in. over Florida and the northwestern United

States, respectively (Hirschboeck 1991). The primary

sources of moisture that lead to higher average precipitation over the southeastern United States, including the

Assessment area, are the Gulf of Mexico and the western

Atlantic Ocean. Water vapor carried aloft is transported

northward by upper level winds over much of the Eastern

United States from the Gulf of Mexico. The transport of

water vapor by weather systems is most prominent during

the spring and summer (Hirschboeck 1991).

Average yearly precipitation over the Assessment

area and surrounding areas reflects the large-scale,

northwest-to-southeast variation in precipitable water

over the United States, with southern Arkansas averaging more than 55 in. of precipitation while northern

Missouri and eastern Kansas average about 35 in./year

(fig. 1.19). The topography of the Assessment area also

plays a significant role in influencing precipitation in the

region. A yearly average maximum of more than 55 in.

of precipitation can be found in parts of the Ouachita

Mountains. The decrease in yearly precipitation between Arkansas and eastern Oklahoma is quite significant. Throughout the central sections of the Assessment

area, precipitation is about 40 to 45 in./year.

Figure 1.20 shows the average precipitation over the

Assessment area for January, April, July, and October.

During the winter, a very strong northwest-to-southeast

gradient in precipitation exists over the region. In

January, amounts range from about 1 inch in northwestern Missouri to more than 4.5 in. in southeastern

Arkansas (fig. 1.20). The spatial change in precipitation

is most significant in Arkansas and southeastern

Missouri. From January to March, average monthly

precipitation generally increases over the region,

especially in Missouri and over the Ouachita Mountains

in Arkansas. In March, precipitation ranges from 2.5 in.

in northwestern Missouri to more than 5.5 in. over the

Ouachita Mountains.

32
Figure 1.20—Average monthly precipitation (in inches) during January, April, July, and October in the region

within and surrounding the Ozark-Ouachita Highlands Assessment area.

33
With the onset of higher temperatures during the

spring months and more convective precipitation events

(heat-induced cloud formation with associated rainfall),

the average monthly precipitation patterns change

dramatically from the wintertime pattern. In April and

May, the area of maximum precipitation over the

Assessment area shifts to the west, while precipitation

over Missouri continues to increase. In April (fig. 1.20),

average precipitation totals range from about 3.5 to 4.5

in. in Missouri and from about 4.0 to 5.5 in. in Arkansas.

The peak in total precipitation shifts to west-central

Arkansas and eastern Oklahoma in May, with amounts

exceeding 6 in. in this area. The increase in convective

precipitation events over the southern and central Great

Plains during the spring leads to a general increase in

monthly precipitation from east to west over the region.

In June, the driest sections of the Assessment area

generally can be found in eastern Missouri and eastern

Arkansas—where precipitation totals for the month

average less than 4 in.—and northeastern Arkansas and

southern Missouri where there is less than 3.5 in. These

totals greatly differ from precipitation totals exceeding 5

in. in western Missouri and eastern Kansas. Low

precipitation also occurs over the Arkansas Valley

between the Boston and Ouachita Mountains in western

Arkansas; this area receives about 3.5 to 4.0 in. of rain

in June.

During most of the summer, more rain tends to fall in

northern Missouri than in any other part of the Assessment area, except in July when the southern slopes of

the Ouachita Mountains tend to experience a peak in

precipitation as well (fig. 1.20). Typical monthly precipitation totals range from about 4.5 in. in northern Missouri to 3.5 to 4.0 in. over the rest of the Assessment

area in July, excluding the Ouachita Mountains region

where precipitation totals in July tend to exceed 4.5 in.

A sharp decrease in precipitation is evident moving

southwestward into northeastern Texas, where totals in

July fall below 2.5 in. By late summer, the wettest

portions of the Assessment area are again the western

sections of Missouri and Arkansas. In September,

average precipitation ranges from 3.5 to 4.0 in. over the

eastern half of Missouri and Arkansas. Average rainfall

is a bit higher at 4.5 to 5.0 in. over the far western

sections of Missouri and Arkansas and the far eastern

sections of Kansas and Oklahoma. The east-to-west

gradient in precipitation in September is similar to the

precipitation gradient observed in June.

From October (fig. 1.20) to December, the location of

the peak monthly precipitation moves from the southern

slopes of the Ouachita Mountains to the far southeastern

section of Arkansas and into Mississippi and Louisiana.

By late fall, the east-to-west gradient in precipitation

observed during the late summer and early fall is replaced by the normal wintertime northwest-to-southeast

gradient. The relative maximum precipitation in southwestern Arkansas (> 4.5 in.) moves slightly eastward in

November and increases to about 5.5 in. Average

precipitation totals in November also decrease quite

rapidly from southeastern Missouri (∼ 4.5 in.) to northwestern Missouri (∼ 1.8 in.). Most of Arkansas experiences between 4 to 5 in. of precipitation in November.

December brings an overall reduction in precipitation

over the entire region, ranging from less than 1.5 in. in

northwestern Missouri to about 5 in. in the far southeastern sections of Arkansas. Average precipitation in

December shows significant northwest-to-southeast

variations over the entire region, with the largest northwest-to-southeast variation existing along a line from

west-central Arkansas to north-central Arkansas.

Extreme Precipitation Occurrences

Extreme precipitation events in the Assessment area

can lead to floods that can have a profound effect on

the region’s natural resources. For example, floods can

decrease nutrient, trace metal, and organic chemical

concentrations in streams and deposit gravel in streambeds, which can enhance fish spawning (USDI GS

1991). Flooding can increase the concentrations of

contaminants in reservoirs and increase algal blooms

(noticeable growth of fresh water algae) within them as

a result of enhanced nutrient concentrations. Floods also

can deposit large amounts of sediment on croplands, at

times destroying food crops. Finally, property damage

associated with extreme precipitation events and

flooding can create severe economic stress on a region.

Extreme precipitation events that can lead to flooding

depend on the amount of precipitable atmospheric water

vapor present coupled with an uplift mechanism that can

steer water vapor aloft to higher altitudes where

condensation can occur, thereby producing clouds and

34
eventual precipitation (Hirschboeck 1991). The lifting of

moist air can be accomplished through (1) convectional

processes like thunderstorms, mesoscale convective

complexes (organized, multiple-celled thunderstorm

systems), and tropical cyclones; (2) the large-scale

convergence of air masses and associated extratropical

cyclones and frontal passages; and (3) orographic

(mountain-related) effects. All of these mechanisms can

play a role in the occurrence of extreme precipitation

events in the Assessment area.

Thunderstorm activity in the Assessment area is

most common during the spring, summer, and fall. On

average, thunderstorms develop in the region from 10 to

25 days during each of these seasons. The number of

thunderstorms during the winter is usually fewer than

10. Although thunderstorms are relatively small in size,

they can produce intense precipitation and cause flash

floods in small drainage basins. Mesoscale convective

complexes can produce both local and widespread

intense precipitation. They can produce significant

flooding because of their size (> 40,000 mi2

) and

duration (6 to 36 hours). In the Assessment area,

mesoscale convective complexes are most common

during the spring and summer. Tropical cyclones (e.g.,

hurricanes, tropical storms, and tropical depressions)

and associated thunderstorms embedded within them

are responsible for many extreme precipitation events in

the southern and eastern sections of the United States.

Tropical cyclones have typical diameters on the order of

60 to 600 mi when they are fully developed, usually

from June to October. Those that impact the Assessment area usually originate over the Gulf of Mexico or

Caribbean Sea. Flooding from tropical cyclones can be

both local and widespread.

Precipitation associated with extratropical cyclones

and frontal passages is usually characterized as covering a larger geographical area and being less intense and

of longer duration than the precipitation associated with

convectional processes. However, the convergence of

air masses along frontal boundaries can lead to significant convection, thunderstorm development, and intense

precipitation. Large-scale riverine flooding and local

flash flooding are possible under these conditions. Even

though precipitation tends to be less intense with

extratropical cyclones, such cyclones are responsible for

most of the major floods that occur in large drainage

basins in the conterminous United States (Hirschboeck

1991). Extratropical cyclones mostly affect the Assessment area during winter and spring. They usually

originate in the Western United States and move

eastward across the Great Plains into the Eastern

United States.

The topographically forced lifting of air as it passes

over hills or mountains can result in the formation of

orographic clouds that may produce precipitation

(Wallace and Hobbs 1977). As air is forced upward

when prevailing winds pass over hilly or mountainous

terrain, it can cool sufficiently at higher altitudes to allow

for cloud formation and potential precipitation. Precipitation associated with orographic lifting is usually found

along the windward slopes of hills or mountains and can

be locally intense. Orographic lifting in combination with

convectional processes or the convergence of air

masses can result in significant precipitation events and

potential flooding. Within the Assessment area, topography plays an important role in precipitation events. The

Ouachita Mountains and Ozark Plateaus are important

topographic features that are responsible for orographic

lifting effects. Depending on the direction of prevailing

winds and the moisture content of the atmosphere over

the Assessment area, extreme precipitation events are

possible along the windward slopes of these topographic

features.

For this Assessment report, an “extreme precipitation

event” is defined as an event occurring within 24 hours

that results in 2 or more in. of precipitation. Large

amounts of precipitation and flooding are certainly

possible from longer lasting events. However, to identify

areas of extreme precipitation, the Aquatic Team used

this definition. Figure 1.21 shows the total number of

extreme precipitation events that have occurred over

the Assessment area from 1950 through 1993. Westcentral Arkansas experienced more than 200 extreme

precipitation events during the 44 years, equivalent to

about 4 or 5 events per year. In this portion of the

Assessment area, orographic lifting associated with the

Ouachita Mountains plays a significant role in precipitation processes. The number of extreme events was less

in Missouri; the northeastern half of Missouri experienced less than 100 events during the 44 years.

The monthly distribution of extreme precipitation

events over the 44-year period indicates important

35
seasonal changes in the number and locations of these

events. Figure 1.22 shows the number of extreme

precipitation episodes that occurred from 1950 through

1993 over the Assessment area during January, April,

July, and October. For the months of December, January, and February, more extreme events tend to occur in

the southeastern quarter of Arkansas. For example, in

January, 10 to 15 extreme precipitation events occurred

from 1950 through 1993 over this part of Arkansas. The

numbers of extreme events for December and February

over this same area were slightly higher, exceeding 20

events in parts of southern and east-central Arkansas in

December and in the far southeastern parts of Arkansas in February. For December, January, and February,

fewer than four extreme events on average characterized most of Missouri.

During spring, more extreme precipitation events

tend to occur over the entire Assessment area than

during the colder winter months. As shown in fig. 1.22,

more extreme events tend to occur in western Arkansas

and eastern Oklahoma (Ouachita Mountains) with the

onset of warmer spring weather. Although still rare,

extreme precipitation events in Missouri during April

also are more frequent than wintertime events. The

Ouachita Mountains have experienced more heavy

precipitation events in May than in any other month.

More than 32 events occurred from 1950 through 1993

in this part of the Assessment area.

The summer months are characterized by a shift in

locations of extreme precipitation events from southwestern Arkansas to eastern Oklahoma and Kansas

and western and northern Missouri. More than 20

events have occurred in parts of northwestern and

west-central Missouri, while fewer than 10 events have

occurred in parts of north-central Arkansas and eastcentral Missouri during July. The shift in locations of the

relative maximums of extreme events is consistent with

the similar shift in relative maximums of average

monthly precipitation totals during the summer.

With the return of cooler conditions during the fall,

extreme precipitation events in Missouri become much

less frequent. The maximums in the number of events

that characterize the western sections of Missouri and

the eastern sections of Kansas in summer disappear

during the fall. In October, the preferred location for

extreme precipitation is over southeastern Oklahoma

and southwestern Arkansas (fig. 1.22). Very few

extreme events have occurred over the eastern half of

Missouri in October. In November, extreme events are

rarest in the northern half of Missouri, and most common in central Arkansas. More events also tend to

occur in southeastern Missouri in November than in

October. By late fall, most extreme precipitation events

tend to occur in southeastern Arkansas and over the

Ouachita Mountains in southwestern Arkansas.

Droughts

Most definitions of drought incorporate the characteristic of abnormal dryness (McNab and Karl 1991);

drought is most often recognized during seasons when

substantial precipitation is expected but fails to occur

(Karl and others 1987). The lack of precipitation over a

region for an extended period is the result of persistent

atmospheric circulation patterns that are not conducive

to precipitation (Namias 1985). For example, high

Figure 1.21—Total number of occurrences where

daily precipitation was 2 inches or more in the

region within and surrounding the Ozark-Ouachita

Highlands Assessment area from 1950 through

1993.

36
Figure 1.22—Total number of occurrences where daily precipitation was 2 inches or more in January, April,

July, and October in the region within and surrounding the Ozark-Ouachita Highlands Assessment area from

1950 through 1993.

37
pressure (anticyclonic) circulations over a region usually

result in very little precipitation. If this type of circulation

pattern persists for an extended period, drought probabilities are likely to increase. Drought occurrence over

a region is also possible when weather systems consistently produce only minimal precipitation (Bergman and

others 1986, Karl and Young 1987).

In addition to a lack of precipitation, droughts are also

associated with higher than normal surface temperatures and drier than normal atmospheric moisture

contents. There are many examples of past drought

occurrences where average surface air temperatures

exceeded normal temperatures for an extended period

of time (Bergman and others 1986; Karl and Young

1987; Namias 1982, 1983; Karl and Quayle 1981).

However, some droughts are associated with lower than

normal surface temperatures (Namias 1966). Relative

humidity values are typically lower than normal during

droughts, and these values usually characterize all levels

of the atmosphere that contain substantial water vapor

(Namias 1966).

Numerous droughts have occurred over the Assessment area during the past 50 years. The U.S. Department

of the Interior Geological Survey (USDI GS 1991) noted

that in Missouri, four major droughts occurred between

1950 and 1991: 1952 to 1957—statewide, 1962 to 1969—

statewide, 1975 to 1982—statewide, and 1988—northern

part of the State. In Arkansas, five major droughts

occurred between 1950 and 1991: 1954 to 1956—

statewide, 1963 to 1967—statewide, 1970 to 1972—

statewide except southwest and northeast corners, 1976

to 1978—statewide except the north-central section, and

1980 to 1983—the northern part of the State).

The National Drought Mitigation Center (1997)

examined the amount of time individual climate divisions

within States experienced severe drought conditions,

defined by a Palmer Drought Severity Index value of -3

or less (Palmer 1965) over 10-year periods beginning in

1900. From 1950 to the present, the most severe

drought conditions over a decade in the Assessment

area occurred from 1950 to 1959. During this period, the

southwestern section of Missouri was under severe

drought conditions 40 to 50 percent of the time while the

west-central and northwestern sections of Missouri

were under severe drought conditions 30 to 40 percent

of the time. Less severe drought conditions were

present in eastern Missouri and in Arkansas. Severe

drought conditions were also prevalent throughout the

southern Great Plains and eastern Rocky Mountains

during the 1950’s. From 1960 to the present, 10-year

drought conditions have not been significant over the

Assessment area, as measured by extended periods of

Palmer Drought Severity Index values of -3 or less.

Tornadoes

The Assessment area is located in that portion of the

United States called “Tornado Alley.” This area of

relatively frequent tornado occurrence encompasses the

southern and central Great Plains and the lowland areas

of the Mississippi, Ohio, and lower Missouri River

Valleys. Specific atmospheric conditions are required for

tornadoes to develop. Such favorable conditions frequently occur over the central portions of the United

States and include: (1) a large supply of atmospheric

moisture (northward transport of moisture from the Gulf

of Mexico), (2) low-level wind shear (wind speed

increase with height and wind-direction shift from

southerly at low levels to southwesterly and westerly at

mid-levels of the atmosphere), and (3) a dry and stable

atmospheric layer above the moist low-level atmospheric layer. The atmospheric conditions that can lead

to severe thunderstorm development and tornado

occurrence are more frequent over “Tornado Alley”

than over other parts of the Nation.

Each year in the United States, tornadic winds are

responsible for death, injury, and millions of dollars in

damages to property and natural resources. Wind

speeds associated with tornadoes can range from about

40 mi per hour (mi/h) up to about 320 mi/h. Tornadoes

are classified according to the amount and type of wind

damage they cause using the Fujita Scale, which ranks

tornado intensity from F0 through F5:

• F0 (40 to 72 mi/h): gale tornado that causes light losses

such as damage to chimneys, breakage of tree

branches, and the pushing over of shallow-rooted trees.

• F1 (73 to 112 mi/h): moderate tornado that can peel

the surface off roofs, push mobile homes off their

foundations or overturn them, and push autos off

roads.

• F2 (113 to 157 mi/h): significant tornado that can pull

roofs off frame houses, demolish mobile homes, push

boxcars over, and snap or uproot large trees.

38
• F3 (158 to 206 mi/h): severe tornado that can tear the

roof and walls off well-constructed houses, overturn

trains, and uproot most trees in a forest.

• F4 (207 to 260 mi/h): devastating tornado that can level

well-constructed houses, blow structures with weak

foundations considerable distances, and throw cars.

• F5 (261 to 318 mi/h): incredible tornado that can lift

strong frame houses off foundations and carry them

considerable distances, move automobile-sized

missiles through the air in excess of 100 yards,

debark trees, and badly damage steel-reinforced

concrete structures.

Most reported tornadoes are classified as F0, F1, or

F2 tornadoes. For example, out of the 24 tornadoes

reported in Arkansas in 1995, 17 were F0 tornadoes, 4

were F1 tornadoes, and 3 were F2 tornadoes. Of the 35

tornadoes that were reported in 1996 in Missouri, 22

were F0 tornadoes, 8 were F1 tornadoes, 3 were F2

tornadoes, and 2 were F3 tornadoes.

Between 1950 and 1994, 1,166 tornadoes were

reported in Missouri and 854 tornadoes were reported

in Arkansas. Missouri and Arkansas rank 7th and 16th

,

respectively, in the number of reported tornadoes from

1950 through 1994 in the entire country. During these

45 years, 279 and 155 fatalities due to tornadoes

occurred in Arkansas and Missouri, respectively.

Arkansas ranked third in the Nation in fatalities due to

tornadoes, while Missouri ranked12th. Injuries attributed

to tornadoes ranged from 3,697 in Arkansas to 2,252 in

Missouri, corresponding to ranks of 5th and 15th

, respectively. The dollar losses (adjusted by the Consumer

Price Index) due to these tornadoes from 1950 through

1994 were about $517 million in Arkansas and $739

million in Missouri.

Figure 1.23 shows the yearly distributions of reported

tornadoes in Arkansas and Missouri during the 1950

through 1995 period. Missouri tends to have slightly

more tornadoes each year than Arkansas. Over the 46

years, an average of 26 tornadoes per year were

reported in Missouri; Arkansas averaged 19 reported

tornadoes yearly. Peak numbers of reported tornadoes

in Missouri occurred in 1967, 1973, and 1982. Arkansas

also experienced relatively large numbers of tornadoes

in 1973, 1978, 1979, and 1982. There is no statistically

significant long-term trend in the number of tornadoes

occurring in this region based on the 1950 through 1995

data.

Although tornadoes have been reported during every

month of the year in Arkansas and Missouri, there are

certain months in which tornadoes are more likely to

occur. Figure 1.24 shows the distribution by month of

the number of reported tornadoes that occurred from

1950 through 1995 in these States. More tornadoes tend

to occur during April and May over this region than in

any other months. In Arkansas, April is the peak month

for tornado activity, while in Missouri, most tornadoes

Figure 1.23—Total number of reported tornadoes in Arkansas and Missouri from 1950 through 1995.

0

10

20

30

40

50

60

70

80

90

1950 1955 1960 1965 1970 1975 1980 1985 1990 1995

Year

Number of tornadoes

Arkansas

Missouri

39
are reported in May. Although Missouri typically

experiences more tornadoes during an entire year,

tornado activity is usually greater in Arkansas during

January, February, and March. This is due to the greater

probability of severe thunderstorm development in more

southern latitudes during winter. By April, tornado

activity in Missouri usually exceeds the activity in

Arkansas and remains greater throughout the late spring

to mid-autumn. The number of reported tornadoes in

May and June from 1950 through 1995 was considerably larger in Missouri than in Arkansas. Figure 1.24

suggests that tornado activity in the region falls off

significantly in the months of July and August. Less than

25 tornadoes were reported for the month of August

from 1950 through 1995 in Arkansas and Missouri. The

numbers are somewhat higher for September and show

a marked decrease for January and February with the

onset of the region’s lowest average temperatures.

Runoff

Runoff is the water that drains from the land into

stream or river channels after precipitation. Runoff

volume is a function of the combined influence of

precipitation, topography, geology, soil moisture, and

other factors. Mean annual runoff per square mile of

basin is often used to compare runoff characteristics

between basins. Mean annual runoff can be computed

by dividing the mean annual volume of water leaving the

basin (measured as streamflow at a gauging station) by

the area of that basin.

Mean annual runoff within the Ozark-Ouachita

Highlands Assessment area is shown in figure 1.25

(Gebert and others 1987). Mean annual runoff generally

is least in the Osage Plains, where it ranges from 8 to

10 in. Mean annual runoff in the Springfield and Salem

Plateaus and St. Francois Mountains generally ranges

from 10 to 15 in., although values are more variable in

the eastern Salem Plateau, where they range from

about 8 to 16 in. per year. Mean annual runoff in the

Boston Mountains ranges from 14 to 20 in. Mean

annual runoff is about 16 in. in the Mississippi Alluvial

Plain at the eastern edges of the Assessment area

(Gebert and others 1987). The mean annual runoff

generally is greatest in the Arkansas Valley and

Ouachita Mountains, where it ranges from 8 to 22 in.

and 14 to 22 in., respectively.

Figure 1.24—Total number of reported tornadoes each month in Arkansas and Missouri from 1950

through 1995.

0

50

100

150

200

250

300

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Month

Number of tornadoes

Arkansas

Missouri

40
14

15 16

18

18

20

22

8

10

10

12

14

8

15

16

18

20

22

Line of equal mean

 annual runoff

(interval 1 or 2 inches)

Aquatic study area

Kansas

Oklahoma

Missouri

Arkansas

Figure 1.25—Mean annual runoff (in inches) in the aquatic study area from 1951 through 1980 (Gebert and others 1987).

Geology

The Ozark Plateaus Province is diverse in lithology,

mineralogy, and structure. Rock formations include

igneous, metamorphic, and sedimentary rocks. Secondary mineralization has occurred in many of the rock

units, and uplifting has resulted in fracturing and faulting

of the rock units. All of these factors contribute to the

unique hydrogeology of the Ozark Plateaus.

The Ouachita Province geology is composed predominantly of clastic (fragmented) rock strata that have

been intensely folded and faulted. Rock strata present

today are the highly eroded roots of the frontal element

of the Ouachita orogenic belt (a mountainous belt

formed by folding of the Earth’s crust). Rock formations

include igneous and sedimentary rocks. Both primary

and secondary mineralization has occurred in many of

the Ouachita Province rock units.

41
Geologic Setting of the Ozark Plateaus Province

The stratigraphy of the Ozark Plateaus is complex.

Its basement crystalline rocks are overlain by a

sequence of sedimentary rocks of Paleozoic-age

(fig. 1.26). The sedimentary-rock sequence consists

of Cambrian- through Mississippian-age dolomites

and limestones in some areas, and Pennsylvanian-age

sandstones, shales, and some limestones in other areas.

Pre-Cambrian Units

Basement Pre-Cambrian-age igneous and metamorphic rocks underlie the Ozark Plateaus and crop out in

several places in the eastern and western parts of the

Assessment area (fig. 1.27). Elsewhere, these rocks are

buried under as much as 5,000 ft of sedimentary rock.

The igneous rocks are mainly felsic (silica rich) rocks

such as granite and rhyolite with mafic (silica poor)

intrusions consisting of diabase and gabbro (Kisvarsanyi

1981). Felsic rocks contain minerals such as quartz and

potassium feldspar, which are resistant to weathering. In

contrast, the mafic rocks contain minerals such as

pyroxene and calcium plagioclase, which weather easily.

The igneous rocks also contain commercially important

quantities of several metals, including iron, copper,

manganese, and silver (Kisvarsanyi 1981).

Cambrian and Ordovician Units

Cambrian- and Ordovician-age rocks crop out mainly

in the Salem Plateau (fig. 1.27). (Refer to fig. 1.1 for

province locations.) The rocks range in thickness from

less than 50 ft to more than 4,000 ft and average about

2,000 ft (Imes 1990a, b, c) and consist predominantly of

dolomites, cherty dolomites, sandstones, and limestones

(Caplan 1960).

The basal unit of the Cambrian and Ordovician rocks,

the Lamotte Sandstone (Late Cambrian age), rests

unconformably (in broken sequence) on Pre-Cambrianage igneous rocks and is a well-sorted quartz sandstone.

The Bonneterre Formation is a fine- to medium-grained

dolomite or limestone that crops out near the St.

Francois Mountains; in southeastern Missouri, it contains abundant lead- and zinc-sulfide deposits. The

Davis Formation and Derby-Doe Run Dolomite are

shaley to silty glauconitic dolomites that crop out in a

roughly circular band around the St. Francois Mountains

(Caplan 1960) and are relatively impermeable compared

to the other Cambrian- and Ordovician-age units (Imes

and Emmett 1994).

The Potosi and Eminence Dolomites, which represent the top of the Cambrian section, are fine- to

coarse-grained dolomites with dense chert, drusy quartz,

and, in northern Arkansas, glauconitic green shale

(Caplan 1960). Both units contain barite, mined in eastcentral Missouri (Wharton and others 1975).

The Gasconade Dolomite consists of a basal sandstone member, the Gunter Sandstone, and upper and

lower dolomite members (MacDonald and others 1975).

The Gunter Sandstone is a fine- to coarse-grained

quartz sandstone (Caplan 1960). Chert is present in the

upper minor and lower dolomite members and in some

places can constitute more than 50 percent of the lower

member.

The Roubidoux Formation consists of sandstones,

dolomites, and cherty dolomites (Thompson 1991) and

crops out extensively in central, south-central, and

southeastern Missouri. The dolomites are finely to

medium crystalline, and the sandstones are loosely

cemented.

The Jefferson City, Cotter, and Powell Dolomites and

the Smithville Formation consist of dolomite with chert,

sandstone lenses, and a few shale beds. These units are

pyritic, and the Smithville Formation contains lead and

zinc ore. The units are exposed in southern Missouri and

northern Arkansas (Caplan 1960).

The Everton Formation contains sandy dolomite and

sandstone members that crop out extensively in northern

Arkansas. The St. Peter Sandstone overlies the Everton

Formation, crops out mainly in northern Arkansas and

into eastern Missouri, and is a loosely cemented sandstone containing well-rounded quartz grains.

Silurian and Devonian Units

Silurian- and Devonian-age rocks are thin and most

are not laterally continuous in the Assessment area (fig.

1.27). Most of the units in this interval exist only in

northern Arkansas and parts of Missouri. The most

significant unit is the black, pyritic, thinly bedded Chattanooga Shale that averages about 70 ft thick (Wise and

Caplan 1979).

42
Southern 

Missouri

Southeastern 

Kansas

Northeastern 

Oklahoma

Northern 

Erathem

System

Arkansas

Kansas City 

 Group 

Pleasanton 

 Formation 

Marmaton 

 Group 

Cherokee Shale

Kansas City 

 Group 

Pleasanton 

 Group 

Marmaton 

 Group 

Cherokee 

 Group

Marmaton 

 Group 

Cabaniss 

 Group 

Krebs 

 Group 

Atoka 

 Formation 

Bloyd 

 Shale 

Hale 

 Formation

Atoka 

 Formation 

Bloyd 

 Shale 

Hale 

 Formation 

Pitkin 

 Limestone

Pitkin 

 Limestone

Paleozoic

Mississippian Pennsylvanian

Fayetteville 

 Shale 

Batesville 

 Sandstone 

Hindsville 

 Limestone 

Carterville 

 Formation

Fayetteville 

 Shale 

Batesville 

 Sandstone 

Hindsville 

 Limestone

Fayetteville 

 Shale 

Batesville 

 Sandstone

Moorefield 

 Formation

St. Louis 

 Limestone 

Salem 

 Limestone 

Warsaw 

 Limestone 

Keokuk 

 Limestone 

Burlington 

 Limestone 

Elsey 

 Formation 

Reeds Spring 

 Limestone 

Pierson 

 Formation

St. Louis 

 Limestone 

Salem 

 Limestone 

Warsaw 

 Limestone 

Keokuk 

 Limestone 

Burlington 

 Limestone 

Fern Glen 

 Limestone

Moorefield 

 Formation

Keokuk 

 Limestone

Boone 

 Formation

St. Joe 

 Limestone

Springfield Plateau aquifer

Ozark Plateaus aquifer system

Boone 

 Formation

St. Joe 

 Limestone

Western Interior Plains confining system

Post-Paleozoic sediments

Savanna

 Formation

McAlester

 Group

Hartshore

 Sandstone

Atoka

 Formation

Johns Valley

 Shale

Jackfork

 Group

Stanley

 Shale

Hydrogeologic

Hydrogeologic

unit

Ozark Plateaus Province

Ouachita

Province

system

Figure 1.26—Stratigraphic column of the Assessment area (continued).

43
Mississippian

Ozark confining unit

Chattanooga 

 Shale

Chattanooga 

 Shale

Woodford 

 Chert 

Chattanooga 

 Shale

Paleozoic

Ordovician Devonian

Ozark Plateaus aquifer system

Burgen 

 Sandstone

Northview 

 Shale 

Sedalia 

 Limestone 

Compton 

 Limestone

Chouteau 

 Limestone

Northview 

 Equivalent

Compton 

 Equivalent

Chattanooga 

 Shale

Callaway 

 Formation 

Fortune 

 Formation

Sallisaw 

 Formation 

Frisco 

 Limestone

Clifty 

 Limestone 

Penters 

 Chert

St. Clair 

 Limestone

Lafferty 

 Limestone 

St. Clair 

 Limestone 

Brassfield 

Silurian

 Limestone

Kimmswick 

 Limestone 

Plattin 

 Limestone 

Joachim 

 Dolomite 

St. Peter 

 Sandstone

Sylvan 

 Shale 

Fernvale 

 Limestone 

Viola 

 Limestone 

Fite 

 Limestone 

Tyner 

 Formation

Cason 

 Shale 

Fernvale 

 Limestone 

Kimmswick 

 Limestone 

Plattin 

 Limestone 

Joachim 

 Dolomite 

St. Peter 

 Sandstone

Ozark aquifer

Upper Arkansas

 Novaculite

 Formation

 Arkansas

 Novaculite

 Formation

Missouri

 Mountain

 Formation

Blaylock

 Sandstone

Polk Creek

 Shale

Big Fork

 Chert

Womble

 Shale

Lower and Middle

Figure 1.26—Stratigraphic column of the Assessment area (continued).

44
Ordovician

Paleozoic

Cambrian

Ozark Plateaus aquifer system

Ozark aquifer

Everton 

 Formation 

Smithville 

 Formation 

Powell 

 Dolomite 

Cotter 

 Dolomite 

Jefferson City 

 Dolomite 

Roubidoux 

 Formation 

Gasconade 

 Dolomite 

Gunter 

 Sandstone

Cotter 

 Dolomite 

Jefferson City 

 Dolomite 

Roubidoux 

 Formation 

Gasconade 

 Dolomite 

Van Buren 

 Formation

Smithville 

 Equivalent 

Powell 

 Dolomite 

Cotter 

 Dolomite 

Jefferson City 

 Dolomite 

Roubidoux 

 Formation 

Gasconade 

 Dolomite 

Van Buren 

 Formation

Everton 

 Formation 

Smithville 

 Formation 

Powell 

 Dolomite 

Cotter 

 Dolomite 

Jefferson City 

 Dolomite 

Roubidoux 

 Formation 

Gasconade 

 Dolomite 

Gunter 

 Sandstone 

Van Buren 

 Formation

Eminence 

 Dolomite 

Potosi 

 Dolomite

Derby-Doe Run 

 Dolomite 

Davis 

 Formation

Bonneterre 

 Dolomite 

Reagan 

 Sandstone 

Lamotte 

 Sandstone

St. Francois 

confining unit St. Francois aquifer

 Precambrian igneous and metamorphic rocks

Basement 

confining unit

Blakely

 Sandstone

Mazarn

 Shale

Crystal

 Mountain

 Sandstone

Collier

 Formation

Mississippian Units

Mississippian-age rocks in the Ozark Plateaus are

predominantly finely to coarsely crystalline limestones

and cherty limestones. These units have a total thickness of about 200 to 500 ft (McFarland and others

1979) and crop out extensively in the Springfield Plateau

(fig. 1.27). (Refer to figure 1.1 for province locations.)

The St. Joe Limestone and the Boone Formation in

northern Arkansas are equivalent to the entire lithologic

sequence that ranges from the Compton Limestone to

the Keokuk Limestone in southwestern Missouri.

Secondary mineralization (mineralization that occurs

after a stratum is initially deposited) is extensive in the

Mississippian-age limestones. Lead- and zinc-sulfide

deposits are present in limestones in southwestern

Figure 1.26—Stratigraphic column of the Assessment area (continued).

45
46

Geologic age

Quaternary

Tertiary

Cretaceous

Pennsylvanian

Mississippian

Devonian and Silurian

Ordovician

Cambrian

Pre-Cambrian

Oklahoma

Arkansas

Missouri

Figure 1.27—Geologic age of major formations underlying the Ozark-Ouachita Highlands and portions of some surrounding physiographic

provinces. (White indicates portions of the aquatic study area for which insufficient data were available.)
47

Missouri, southeastern Kansas, and northeastern

Oklahoma. Pyrite, lead- and zinc-carbonates, and zinc

silicates are also present in these deposits (Kiilsgaard

and others 1967).

Late Mississippian-age rocks overlie the Boone

Formation and its equivalent units and crop out on the

northern flank of the Boston Mountains. These units

include the relatively permeable Hindsville and Pitkin

Limestones, which are separated by the thick, impermeable Fayetteville Shale.

Pennsylvanian Units

Pennsylvanian-age rocks crop out in the Boston

Mountains of northern Arkansas and in the Osage

Plains of western Missouri, southeastern Kansas, and

northeastern Oklahoma (fig. 1.27). In general, Pennsylvanian-age rocks rest unconformably (in broken sequence) on Mississippian-age rocks. However, in the

north-central Ozark Plateaus, Mississippian-age rocks

are missing, and in these locales Pennsylvanian-age

rocks directly overlie Ordovician-age rocks.

In northern Arkansas, three geologic units—the Hale

Formation, the Bloyd Shale, and the Atoka Formation—

are of Pennsylvanian age. The Hale Formation and

Bloyd Shale are massive sandstones with interbedded

limestone, shale, and coal. The Atoka Formation is

mostly dark shales with sandstones and sandy limestones (Caplan 1957).

Pennsylvanian-age rocks in western Missouri, southeastern Kansas, and northeastern Oklahoma consist of

four groups, Cherokee, Marmaton, Pleasanton, and

Kansas City. Lithologies are mostly shales and sandstones with some limestones. Black shales in this Pennsylvanian section can be uranium bearing (Coveney and

others 1987). Bituminous coal beds are present in the

Cherokee and Marmaton Groups (Robertson and Smith

1981). In some places, these same Pennsylvanian-age

rock units yield oil and gas (Anderson and Wells 1967).

Cretaceous Through Quaternary Units

According to Fenneman (1938), Cretaceous- through

Quaternary-age sedimentary strata in or adjacent to the

Ozark Plateaus consist of unconsolidated sands, gravels,

and clays. These sedimentary strata crop out in the

Mississippi Alluvial Plain along Crowley’s Ridge and the

Benton Hills. Thin alluvial deposits in some of the major

stream valleys in the aquatic study area, including the

Mississippi Alluvial Plain, are comprised of Quaternaryage sediments (fig. 1.27). (See figure 1.1 for location of

Mississippi Alluvial Plain.)

Structural Geology of the Ozark Plateaus

The Ozark Plateaus Province is underlain by a

structural dome formed by a series of uplifts that have

gradually occurred since Pre-Cambrian time. The total

uplift is approximately 5,000 ft (McCracken 1967). The

dome is asymmetrical with the dip of sedimentary rocks

greater to the east-southeast than to the south, west, or

north (McCracken 1967). Regional dip east of the St.

Francois Mountains is 150 ft/mi (Tikrity 1968) whereas

regional dip in southwestern Missouri is about 10 ft/mi.

The dip to the south increases to 200 ft/mi in the

southern flank of the Boston Mountains as a result of

faulting in the area (Frezon and Glick 1959).

Extensive fracturing, jointing, and faulting of the

rocks have resulted from the uplifting in northwestern

Arkansas. Fractures generally trend northwest, northeast, and east-west (Ogden 1980, Adamski 1987, Leidy

and Morris 1990). Vertically oriented joints (fractures in

rock that do not displace the rock) are present in many

of the Paleozoic-age rocks and trend east to west, north

to south, northwest to southeast, and northeast to

southwest (McCracken 1971). Major faults in the Ozark

Plateaus have a northwest trend (McCracken 1967).

Displacement can be as much as 1,000 ft. Some of the

major faults form escarpments that are visible for

several miles (Beveridge and Vineyard 1990).

Geological History of the Ozark Plateaus

Pre-Cambrian-age granitic and rhyolitic rocks cooled

and crystallized about 1.2 to 1.5 billion years ago in the

Ozark Plateaus and adjacent areas (Tikrity 1968).

These igneous rocks form the basement lithologic

complex of the Ozark Plateaus. After igneous activity

ceased, the landscape was eroded prior to Late Cambrian time (McCracken 1971). The region experienced

nearly continuous deposition of marine carbonates with

brief periods of erosion and deposition from Late

Cambrian to Middle Ordovician time (Frezon and Glick

1959). Geologic forces uplifted the Ozark Plateaus area
and extensively eroded the sedimentary strata. Geologic

units from the St. Peter Sandstone through Fernvale

Limestone were subsequently deposited, but the uplifting

limited sediment deposition from the Middle Ordovician

to Early Devonian time. After the Early Devonian time,

the Ozark Plateaus area was uplifted and eroded again

(McCracken 1971).

Middle Devonian- and Mississippian-age sediments

subsequently were deposited in the Ozark Plateaus.

Mississippian-age limestones formed from sedimentary

layers deposited in the shallow seas that inundated the

Ozark Plateaus during that age. After Mississippian

time, the northern part of the Ozark Plateaus was

uplifted and tilted. Erosional processes beveled

Devonian- and Mississippian-age rocks, exposing

Ordovician-age rocks over much of the area (Frezon

and Glick 1959, McCracken 1971).

Transgressing seas and riverine systems deposited

Pennsylvanian-age sediments in the Ozark Plateaus.

Periodic uplifts of these rocks formed unconformities

(breaks in the depositional sequence of rock from

dislocations, erosion, and nondeposition) in rocks of

Pennsylvanian age. The Ozark Plateaus area was

uplifted and extensively eroded after Pennsylvanian time

(McCracken 1971). Fluvial and marine sediments were

deposited in Late Cretaceous and Early Tertiary times.

Subsequent uplifting exposed the Ozark Plateaus to

erosion, generating the current topography (McCracken

1971).

Geologic Setting of the Ouachita Province

In the Ouachita Province (refer to figure 1.1),

basement crystalline rocks are overlain by a sequence

of Paleozoic-age and younger sedimentary rocks and

thus the crystalline rocks are not exposed in the

Ouachita Province (fig. 1.26). The sequence of sedimentary rocks consists of predominantly sandstones and

shales of Late Cambrian through Pennsylvanian age.

Strata of the Ouachita Province range in total thickness

from less than 30,000 to approximately 50,000 ft. Rock

types observed are, in order of decreasing abundance,

shale, sandstone, siltstone, chert-novaculite, conglomerate, tuff, and limestone (Stone 1994).

In the Ouachita Mountains section of this province,

sedimentary rocks of deep marine origin dominate PrePennsylvanian strata. In Mid-Pennsylvanian-age strata

(middle and upper Atoka Formation), intervals of shale

and sandstones of shallow marine and deltaic (river

mouth) origin become common. In the Arkansas Valley

section, the presence of the Arkoma Basin was central

to geologic evolution of the area and controlled sediment

deposition. Rock of shallow marine to non-marine origin

dominate from Devonian- through Pennsylvanian-age

parts of the stratigraphic section in the basin.

Ordovician Units

The Cambrian- and Ordovician-age Collier Formation

is the oldest rock exposed in the Ouachita Province

(Ham 1959, Thomas 1977) and consists of black shale

and minor layers of dark, thin-bedded limestone. The

Crystal Mountain Sandstone is composed primarily of

silica- and carbonate-cemented, fine- to medium-grained

sandstones with thin interbedded layers of black shale.

The Mazarn Shale is represented predominantly by

fissile black and green shales with minor occurrences of

sandstone, limestone, and chert layers. The Blakely

Sandstone consists of interbedded shale and silica or

carbonate cemented sandstone. The Womble Shale is

black with thin beds of sandstone and limestone. The

Bigfork Chert consists of thin-bedded, highly fractured,

gray to black chert interbedded with varying amounts of

black shale and rare sandstone and limestone. The Polk

Creek Shale is a black, fissile shale.

Silurian Units

The Blaylock Sandstone is the basal Silurian-age unit

which thins rapidly and disappears in the northern part

of the Ouachita Province. The formation consists of

fine-grained, gray sandstone and interbedded dark shale.

The Blaylock Sandstone is overlain by the Missouri

Mountain Formation consisting of shale and sandstone.

Devonian and Mississippian Units

The Arkansas Novaculite is a principal formation in

the central Ouachita Province and composes the

Devonian System part of the Mississippian System. The

Arkansas Novaculite crops out almost continually from

Pulaski County, AR, west to McCurtain County, OK, in

a band of narrow, parallel belts trending east to west.

The Stanley Shale overlies the Arkansas Novaculite and

is composed of dark, fissile shale interbedded with finegrained sandstone.

48
Pennsylvanian Units

Pennsylvanian System rocks in the Ouachita Province, including the Arkansas Valley, are primarily represented by the Jackfork Group, the Johns Valley Shale,

the Atoka Formation, the Hartshorne Sandstone, the

McAlester Group, and the Savanna Formation. These

stratigraphic units compose a sequence predominantly of

shales and sandstones that exceed 30,000 ft in thickness

in some areas. The Jackfork Group is predominantly

sandstone interbedded with a subordinate amount of

dark shale. The Johns Valley Shale is a gray to black.

The Atoka Formation is a dark shale that crops out

across a large area of the northern part of the province

but is present, in part, in the southern Athens Piedmont

Plateau and elsewhere. The Hartshorne is a coarsegrained sandstone with brown silty shales and coal

(Stroud and others 1969). The McAlester is a dark gritty

shale with fine-grained sandstone and coal (Stroud and

others 1969). The Savanna consists of sandy shale with

coarse-grained sandstone and coal (Stroud and others

1969). The Boggy consists of dark clay with coarsegrained sandstone and coal (Stroud and others 1969).

Cretaceous through Quaternary Units

The sedimentary strata of the Cretaceous through

Quaternary age consist of unconsolidated sands,

gravels, and clays. These strata crop out as thin alluvial

deposits along the Arkansas River and in some of the

major stream valleys in the Assessment area.

Structural Geology of the Ouachita Province

The Ouachita Province is generally divided into two

structural zones: the Ouachita Mountains proper and the

Arkoma Basin, which correspond to the Ouachita

Mountains and Arkansas Valley physiographic sections,

respectively. The water-bearing rock formations in this

area were created by three ancient geologic processes:

(1) the formation of a subsiding basin into which a large

mass of sediments was deposited, (2) the deformation

of the resulting rocks into a complexly folded and thrustfaulted mountain belt, and (3) a long period of slow uplift

and erosion (Albin 1965).

The Ouachita Mountains represent the primary

outcrop region of the external fold and thrust belt of the

Late Paleozoic collisional-subductional orogeny (period

of tectonic mountain building). The degree of structural

intensity resulting from compression during the mountain

building is much greater in the Ouachita Mountains than

in the rest of the Assessment area. Shortening (decrease in the original breadth of the rocks in the lateral

dimension parallel to compressive forces) of the crustal

rocks is about 50 percent in the central portion (Arbenz

1989a). Prominently observed structures are folds,

thrust faults, and reverse faults. Folding ranges from

open to tight with steeply dipping limbs. Overturned

folds are common and thrust and reverse faults are

densely spaced. The more brittle rocks, such as the

sandstones, cherts, novaculite, and hard shales, are

intensively fractured, resulting from the intense stresses

experienced during mountain building.

The Arkoma Basin represents the extreme frontal

element of the original orogenic belt and is a mildly

compressed fold belt that diminishes in the north. Broad

anticlines and synclines, normal faults, and thrust faults

characterize the structural geology of the area. Shortening observed in the fold belt is on the order of 5 percent

and decreases to 0 percent in the north (Arbenz 1989a).

In the northern part of the basin, folds generally exhibit

dips of less than 10 degrees, except near normal faults

where dips are more exaggerated. In the southern part

of the basin, stratigraphic dips up to and beyond vertical

are common. Nonvertical southerly dipping faults

comprise the major fault systems in the basin and

typically have angles of 30 to 65 degrees. Most of the

normal faults are growth faults. Thrust faults are

common in the southern part of the basin where structural intensity was greater (Haley 1982).

The unique stratigraphy and structure of the Ouachita

Province contribute to a unique hydrologic setting,

influencing the character of both surface and ground

water. For example, geologic structure and weathering

history of strata influence the surface flow of precipitation and affect surface drainage distribution and gradients. With respect to ground water, aquifers in the

Ouachita Province are generally very discontinuous

because of faults and complex underlying geologic

structure. The intense fracturing seen in the strata that

contain aquifers facilitates the flow of ground water but

causes aquifers to be heterogeneous and, thus, somewhat

unpredictable with respect to their distribution and yields.

49
Geological History of the Ouachita Province

The Ouachita Mountains form part of a mountain

range that fringed the southern and eastern margins of

the North American Craton during the Late Paleozoic

and Early Mesozoic eras. This tectonic belt ran somewhat continuously from the Appalachians in the Eastern

United States through the Ouachitas to the Marathon

Mountains in west Texas and beyond into northern

Mexico.

A few wells drilled to basement rock in the Ouachita

Province show that Pre-Cambrian basement rock in the

area is similar to the Pre-Cambrian igneous rocks

exposed in the St. Francois Mountains. From Late

Cambrian to Early Mississippian time, the southern

margin of the North American continental plate (the

area defining the Ouachita Mountains) was passive

tectonically. It received sediments from shallow- and

deep-water deposition at a stable and relatively slow

rate, which formed rocks of these geologic ages now

seen in the Ouachita Mountains. The Late Paleozoic

orogeny began to affect sedimentation in the southern

marginal area in Mid-Mississippian time. Deep-water

sedimentation began at very high rates and continued

through Middle Pennsylvanian time, resulting in total

thicknesses of strata over basement rock as great as

50,000 ft. Major deformation, thrusting, and folding of

basinal rock strata began during Middle Pennsylvanian

time; collision of continental plates and resultant thrusting

pushed these rocks onto the continental shelf (Arbenz

1989b). During Late Pennsylvanian time, the Arkoma

Basin Formation sediments were mildly compressed,

forming the milder structural deformation observed in the

Arkansas Valley section. The Ouachita Mountains area

rose as a result of epeirogenic uplift (relief-producing

crustal deformation) since the climax of orogenic

deformation in Middle Pennsylvanian time. However,

erosional rates were comparable to or exceeded uplift

rates, and the area was reduced to a peneplain (a vast

area with slight relief shaped by erosion) by the end of

the Mesozoic Era. Renewed uplift and rapid erosion of

less resistant layers of rock lying between belts of more

resistant rock resulted in the present-day Ouachita

physiography of long, even-crested ridges and flat,

intermontane basins. The Athens-Piedmont Plateau and

the floors of the larger basins in the Ouachita Mountains

are parts of the younger Hot Springs Peneplain that had

formed by Early Tertiary time (Albin 1965).

Soils

Soils vary throughout the Assessment area due to

differences in climate, parent material (e.g., sandstone,

limestone, shale), topography (contour of the land), time

of soil development, and soil organisms. Following is a

general description of the soils of the ecological sections

or zones that make up the Assessment area.

The State Soil Geographic (STATSGO) data base

provided the majority of the information for this section.

The USDA Natural Resources Conservation Service

designed STATSGO for regional, multi-State, river basin,

State, and multi-county resource planning, management,

and monitoring purposes. STATSGO consists of statewide soil maps and a relational data base with attributes.

The soil maps are compiled by generalizing more

detailed soil survey maps and contain delineations of

map units from 1 to 21 components. Each component

consists of a phase of a soil series. There are 60 soil

properties and interpretations for 84 different data

elements (for example, flooding) associated with each

component.

Ozark Plateaus Province Soils

The soils of the Ozark Plateaus Province are typically moderately well-drained to well-drained and have

moderate to slow permeability. North of the Boston

Mountains, most of the soils developed in loess (a loamy

material derived from glaciers and transported by the

wind) and in cherty limestone. The soils are generally

old, shallow, stony, highly weathered and acidic, except

on some of the broad ridges and bottomlands. Some of

the soils on broad ridges and bottomlands are neutral to

slightly alkaline compared to the other soils in this

section. Arkana, Moko, Cassville, Viraton, Clarksville,

and Lebanon are names of soil series (groups of soils

with similar characteristics) commonly found in the

Ozark Plateaus. These soils are forested with mixed

oaks, hickories, maples, and eastern red cedar with

areas of native grasses where the trees are sparse.

Farmers use cleared areas as pasture or for growing

corn, small grains, sorghum, and hay.

• The Arkana series includes moderately deep, very

slowly permeable soils that formed in clayey materials. This series weathered from cherty limestone

bedrock on gently sloping to steep ridges and side

slopes.

50
• The Moko series includes shallow, well-drained,

moderately permeable soils that formed in thin loamy

residuum (material that is weathered in place) from

underlying limestone on gently sloping to steep

benches and ridgetops.

• The Cassville series includes moderately deep, welldrained, very slowly permeable soils that formed in

materials weathered from limestone, siltstone, and

shale on nearly level to moderately steep slopes on

the tops and sides of hills.

• The Viraton series includes deep, moderately welldrained loamy soils underlain by cherty limestone

residuum or colluvium, gravelly material derived from

cherty residuum and transported by gravity to foot

slopes and alluvial fans.

• The Clarksville series includes deep, somewhat

excessively drained soils formed in residuum and

locally transported colluvial-alluvial materials (material

moved downslope by gravity and erosion combined

with stream-deposited material). This series was

weathered from cherty dolomite or cherty limestone

on steep side slopes and narrow ridgetops.

• The Lebanon series consists of moderately welldrained soils formed in loess underlain by cherty

limestone on gently to moderately sloping uplands.

The soils of the Boston Mountains physiographic unit

are typically well drained and have moderate

permeabilities. Most of these soils developed in

interbedded acidic sandstones and shales and are old,

highly weathered, and low in both organic matter and

natural fertility.

Some of the common soil series in the Boston Mountains are Linker, Enders, Nella, Mountainburg, Ceda, and

Kenn. The upland soils are forested with mixed oaks,

hickories, sweet gum, and shortleaf pine. Farmers use

cleared areas in the uplands for pasture and growing

cotton, corn, small grains, peaches, and sorghum. The

floodplain soils are forested with mixed oaks, American

sycamore, sweetgum, and shortleaf pine. Cleared

portions of the floodplain are used for pasture.

• The Linker series includes moderately deep, welldrained, moderately permeable soils that formed in

loamy residuum weathered from limestone on broad

plateaus, mountains, hilltops, and benches.

• The Enders series includes well-drained, very slowly

permeable soils that formed in loamy material and

clayey residuum weathered from shale or

interbedded shale and sandstone on crests and side

slopes of mountains.

• The Nella series includes well-drained, moderately

permeable soils on sideslopes, footslopes, and terraces that formed in colluvium (material moved

downslope by gravity and erosion) from weathered

sandstone and shale.

• The Mountainburg series includes soils characterized

by their moderately rapid permeability. They are

well-drained, shallow, and usually found on ridge tops

and side slopes. They were formed in sandstone

residuum.

• The Ceda series includes deep, well-drained, rapidly

permeable soils that formed in loamy alluvium on

nearly level to very gently sloping floodplains.

• The Kenn series includes deep, well-drained, moderately permeable soils that formed in loamy alluvium

on nearly level to gently sloping floodplains.

Ouachita Province Soils

The soils of the Ouachita Mountains are mostly well

drained and have moderate to slow permeabilities. The

soils are highly weathered, acidic, and formed on

surfaces that are 10,000 to 15,000 years old or older.

They formed in material weathered from shale, sandstone, novaculite, and chert. The basins, valley floors,

and lower hills formed in the softer, less resistant shale,

chert, and impure sandstone. The mountains, ridges, and

peaks formed in more resistant novaculite and relatively

pure sandstone.

Some of the common soil series are Carnasaw,

Sherless, Endsaw, Bengal, Avant, and Neff. These soils

are forested with shortleaf pine, red oak, white oak,

black oak, post oak, blackjack oak, hickories,

sweetgum, and blackgum on the uplands and with green

ash, water oak, and willow oak on the floodplains.

Farmers use cleared areas for pastures, and some parts

of terraces and floodplains are used for soybean

production.

• The Carnasaw series includes deep, well-drained,

slowly permeable soils formed in material weathered

from tilted shale and sandstone on uplands.

• The Sherless series consists of moderately deep,

well-drained, moderately permeable soils that formed

in residuum of interbedded shale and sandstone on

the tops and sides of low ridges.

51
• The Endsaw series includes deep, well-drained,

slowly permeable soils that formed in material

weathered from shale on uplands.

• The Bengal series consists of moderately deep, welldrained, slowly permeable soils that formed in

colluvium and residuum weathered from shale.

• The Avant series includes moderately deep, welldrained, moderately permeable soils that formed in

residuum from highly fractured chert bedrock on

mountaintops, sideslopes, and ridges.

• The Neff series consists of deep, somewhat poorly

drained, slowly permeable soils formed in thick

alluvium on floodplains.

The soils of the Arkansas Valley are mostly moderately well to well drained and have moderate to very

slow permeabilities. These soils formed in loamy and

clayey material that weathered from sandstone and

shale. Some of the soils formed in material that was

deposited by streams. The soils in the hills are low in

organic matter and fertility. The soils on the terraces and

floodplains are low to high in organic matter and fertility.

Some of the common soil series are Leadvale,

Spadra, Crevasse, Roxana, and Roellen. The terrace

soils are forested with oaks, hickories, maple, elm,

shortleaf pine, and sweetgum. The floodplain soils are

forested with cottonwood, American sycamore, willow,

and green ash. Cleared areas are used by farmers for

pasture and for growing soybeans, grain sorghum, truck

crops, small grains, alfalfa, and rice.

• The Leadvale series includes deep, moderately welldrained, slowly permeable soils that formed in loamy

sediment weathered from sandstone and shale on

colluvial footslopes and on old stream terraces in

broad valleys.

• The Spadra series includes deep, well-drained,

moderately permeable soils that formed in loamy

alluvium on stream terraces and alluvial fans.

• The Crevasse series consists of deep, excessively

drained, rapidly permeable soils that formed in sandy

alluvial sediments along stream channels.

• The Roxana series includes deep, well-drained,

moderately permeable soils that formed in sandy and

silty alluvial sediments on natural levees along streams.

• The Roellen series includes deep, poorly drained,

slowly permeable soils that formed in clayey alluvium

on floodplains and low terraces.

Changing Land Conditions

Prior to European settlement, the Ozark Plateaus

were primarily oak-hickory forests and oak savannas on

the hilly portions and bluestem prairies on the

undissected plateaus. Lowland forests had a greater

variety of species than upland forests and included

sycamores, cottonwoods, maple, black walnut, butternut,

hackberry, poplar, and bur oak. Prairies were common

only in small patches in the eastern part of the Ozark

Plateaus, but about 50 percent of the western part was

in prairie. Trees were not well established in these

prairies because American Indians and lightning periodically burned the vegetation. Early settlers continued the

practice of burning to provide pastureland. After the

Civil War, however, many of the prairies were allowed

to grow up in trees (Rafferty 1980).

A majority of the woodlands of the Ozark Plateaus

are now second or third growth because of repeated

logging through the years. However, tree species in the

woodlands are similar to those European settlers

encountered.

Land conditions in the Ozark Plateaus today are

primarily those of forest and pasture plus some cropland

(fig. 1.28). (Refer to figure 1.1 for province locations.)

Deciduous forests, mostly oak and hickory, predominate

in the Salem Plateau and Boston Mountains, but mixed

oak-pine occurs in the Upper White River Basin.

Pastureland, which is mostly fescue (used as hay) and

Kentucky blue grass, is found in the river bottoms and

on gentle to steep slopes of the uplands on the Springfield Plateau. Cropland is the predominant land condition

(and land use) in the Osage Plains and Mississippi

Alluvial Plain. Soybeans and sorghum with some corn,

wheat, grains, and other field crops are grown in the

Osage Plains, with rice dominating in the Mississippi

Alluvial Plain.

Poultry, beef and dairy cattle, and hogs are the

dominant livestock raised in the pasturelands of the

Ozark Plateaus. Large concentrations of poultry farms

exist in the southwestern area of the Ozark Plateaus

and in a small area in the north central Ozark Plateaus.

Intensive poultry farming started mainly around northwestern Arkansas in the 1930’s and has expanded

greatly in recent decades, with intensive operations

now extending into southwestern Missouri and

52
northeastern Oklahoma (Rafferty 1980). Dairy cattle

farming is a major land use in the southwestern part and

to a lesser extent in the central part of the Ozark

Plateaus. Commercial dairy farming grew rapidly from

the early through the mid-1900’s in southwestern

Missouri and northwestern Arkansas. In recent years,

dairy farming in the Ozark Plateaus has declined

slightly. Beef cattle and hogs are raised throughout most

of the Ozark Plateaus Province (Rafferty 1980).

Mining has been a major land use in parts of the

Ozark Plateaus. Major deposits of lead, zinc, iron, barite,

and coal and minor deposits of copper, silver, manganese, and tungsten are located in the Ozark Plateaus.

Mining activities in the Ozark Plateaus have occurred

primarily in four main lead-zinc mining districts: the

Southeastern District (Old Lead Belt, Viburnum Trend,

and the Fredericktown subdistricts of southeastern

Missouri), the Tri-State District (Kansas-OklahomaMissouri State line), the Central District (north-central

Ozark Plateaus), and the North Arkansas District. By

far, the most important ore deposits were in the TriState District and the Southeastern District (Wharton

Figure 1.28—Land conditions in the Assessment area.

Land use and cover

Urban

Agriculture

Water

Forest

Oklahoma

Missouri

Arkansas

53
and others 1975). The Southeastern District was

primarily a lead producer, and the Tri-State District was

primarily a zinc and lead producer (Wharton and others

1975). The Central and the North Arkansas Districts

contained relatively small, scattered ore deposits that

were not mined as actively as were deposits in the two

major lead-zinc mining districts (Rafferty 1980). The

Viburnum Trend subdistrict is the only area still actively

mined for lead and zinc (Wharton and others 1975).

Bituminous coal deposits underlie the northwestern

part of the Assessment area. The coal is present in

numerous beds, all associated with rocks of Pennsylvanian age (Robertson and Smith 1981). Historically, coal

production in this area has fluctuated with national and

international economic conditions. Until 1925, most of

the coal was mined underground. Approximately twothirds of the coal mined is used to produce electricity

(Searight 1967).

Prior to European settlement, the Ouachita Mountains and the Arkansas Valley were mostly mixed pine

and hardwood forests, with pines dominating southern

slopes and mixed hardwoods being more common on

northern slopes and in the bottomlands (Foti and Glenn

1991). Prairies and glades were common across the

Ouachita Mountains but were more extensive in the

western portion. By the late 19th century, Europeans

had settled the Ouachita Mountains and cultivated the

best land (Smith 1986). Around 1890, the logging

industry moved into the Ouachita Mountains, and most

of the virgin timber had been cut by 1920. Virtually all

forests in the Ouachitas have been cut at some time in

the past (Smith 1986). However, tree species in the

woodlands are similar to those of the old-growth forests

(Devall and Rudis 1991).

Currently, land conditions in the Ouachita Mountains

and the Arkansas Valley (fig. 1.28) consist primarily of

forest, pasture, and some cropland (the latter concentrated primarily along the Arkansas River floodplain).

Deciduous forest, mostly oak and hickory, is the major

forest type in the Arkansas Valley and bottomlands;

pines are more common to the south in the Ouachita

Mountains. Pastureland is mostly in fescue and bermuda

grasses. Cropland is abundant along the Arkansas River

floodplain with soybeans, corn, rice, and other field

crops most common.

Poultry, beef and dairy cattle, and hogs are the

dominant livestock raised in the area’s pasturelands.

Large concentrations of poultry farms are in the central

and western part of the Ouachita Mountains. Beef

cattle are raised throughout most of the Ouachita

Province. Dairy and hog farming are less common in

the Ouachita Mountains but are important locally.

Mining has been a major land use in parts of the

Ouachita Mountains and Arkansas Valley. Deposits of

bauxite, antimony, mercury, barite, titanium, lead, and

zinc have been mined in the Ouachita Mountains.

Bauxite mining is limited to Pulaski and Saline Counties,

AR. Historically, Arkansas supplied 90 percent or more

of the bauxite mined annually in the United States since

discovery of the ore bodies in 1887 (AR GC 1985).

Currently, many of the mines are inactive because of

the low economic return on remaining ore. Cinnabar, the

primary ore of mercury, has been mined in Pike, Clark,

and Howard Counties, AR; Lake Greeson now covers a

large portion of the mercury district. Barite, a barium

sulfate mineral, has been mined in Hot Spring, Montgomery, and Polk Counties, AR. Stibnite, the sulfide ore

of antimony, has been mined in Sevier County, AR.

Rutile and brookite, ores of titanium, have been mined in

Hot Spring County, AR. Lead and zinc ores, predominantly galena and sphalerite, have been mined in the

west-central Arkansas mineral belt, including parts of

Pulaski, Saline, Hot Spring, Garland, Montgomery, Polk,

Howard, Pike, and Sevier Counties.

In the Arkansas Valley, major deposits of coal,

natural gas, and oil are developed. Commercial mining

of coal on a major scale began in 1870. Coal was mined

in a belt about 33 mi wide and 60 mi long in parts of

Crawford, Franklin, Johnson, Logan, Pope, Sebastian,

and Scott Counties (Stroud and others 1969). The

Arkoma Basin of the Arkansas Valley has been a major

source for production of natural gas and some oil.

Natural gas and condensates are found throughout the

Arkansas Valley. Additional information about land

cover and land use history is provided in the OzarkOuachita Highlands Assessment: Social and Economic Conditions (USDA FS 1999a, Chapters 1, 7,

and 8), and Terrestrial Vegetation and Wildlife (USDA

FS 1999b, Chapter 2).

54
Chapter 2: Status of Aquatic Resources

The first chapter of this report was a general introduction to the physical characteristics of the Assessment

area. Chapter 2 examines two broad categories of the

aquatic ecosystem in the Highlands. “Water Quality”

includes information about the chemical characteristics of

streams, lakes, and ground water. “Aquatic Animals and

their Habitats,” the second major section, discusses the

biological components of water including the status of

fish, mussels, crayfish, aquatic insects, and species of

special concern; commercial and recreational roles of

aquatic species; aquatic habitats; riparian areas; and

wetlands.

Water Quality

Surface Water Quality (Streams)

Question 2.1: What are the status and apparent

trends of the water quality of streams in the

Highlands?

This section describes the quality of the moving (lotic)

surface water in streams of the Assessment area; the

discussion focuses on nutrients, suspended sediment, and

suspended solids. The Aquatic Team defines nutrients in

this report as the various forms of nitrogen and phosphorus. Natural sources of these nutrients in Highlands

streams include: (1) fixation of atmospheric nitrogen by

plants and bacteria, (2) deposition of atmospheric nitrogen

(from lightning), (3) dissolution of rocks or minerals, and

(4) dissolution of soil organic matter and decaying plants

and animals. Anthropogenic sources (originating from

human activities) of nitrogen and phosphorus include

sewage and septic tank discharges, fertilizer applications,

and animal waste.

Background concentrations of nitrogen and phosphorus in streams are generally low because dissolved forms

of the two elements are assimilated rapidly by plants and

bacteria. Aquatic vegetation, particularly algae, requires

nitrogen and phosphorus to grow. When concentrations of

these nutrients in streams or lakes increase beyond

normal levels, they can contribute to a dense growth of

algae (algal blooms). Bacterial decomposition of dead

algal cells after an algal bloom can deplete dissolved

oxygen in the water body and negatively affect aquatic

life (e.g., kill fish).

Nitrogen occurs in surface water as nitrite (NO2

-

),

nitrate (NO3

-

), and ammonium (NH4

+

) ions and in dissolved solutions (Hem 1985). The ammonium ion is in

chemical equilibrium with un-ionized ammonia, which is

toxic to aquatic life under certain conditions. Ammonium

ions predominate at pH values of less than 9.2, which is

above the pH of most natural water (Hem 1985); in other

words, ammonia predominates in most natural water.

(The relative measure of how basic or acidic a substance

is the pH; anything above a pH of 7 is considered basic,

anything below 7 is considered acidic.)

Nitrite and organic forms are unstable in aerated

water, ammonium cations (positively charged ions) tend

to adsorb (bond molecularly) on mineral surfaces, and

nitrate is readily transported in water and is stable over a

wide range of aquatic conditions. The reduced forms of

nitrogen (nitrite, ammonium, and organic forms) are

oxidized to nitrate in most aerobic (oxygen-rich) environments, but in oxygen-poor streams and aquifers, a

substantial portion of the total nitrogen content may be

these reduced forms. High nitrate concentrations are

undesirable in domestic or public water supplies because

of potential health hazards, particularly for infants and

small children. Because of these potential health risks

associated with water-borne nitrates, the U.S. Environmental Protection Agency (EPA) has established a

maximum contaminant level (MCL) of 10 milligrams per

liter (mg/L) of nitrate as nitrogen in drinking water (U.S.

EPA 1987).

The most common phosphorus compound in water is

the fully oxidized orthophosphate ion (PO4

3-), but forms of

organic phosphate synthesized by plants and animals also

constitute a substantial part of the phosphorus in natural

waters (Hem 1985). The orthophosphate ion is the

phosphorus form most readily available for use by aquatic

plants because of its solubility in water. However, most

compounds containing phosphorus are relatively insoluble;

thus they tend to precipitate or be adsorbed onto suspended solids in water.

55
Key Findings

 1. Median concentrations of nitrite plus nitrate,

ammonia, total nitrogen, and total phosphorus

collected at stream sites near sewage treatment

plants in most physiographic areas were

significantly higher than at any other type of site.

 2. Within the Boston Mountains, Springfield and

Salem Plateaus, and Arkansas Valley, nitrite plus

nitrate concentrations at stream sites increased

significantly with more intensive uses of land (e.g.,

acres of “forest-pasture mix” had more of these

concentrations than did “forest” acres).

 3. Where more intensive uses of land occurred in the

Springfield and Salem Plateaus, Arkansas Valley,

and Ouachita Mountains, ammonia concentrations

in streams generally increased significantly. Within

basins that have significant “agriculture” land use,

total phosphorus concentrations were highest at

stream sites in the Arkansas Valley where land

was used for a mix of agriculture and forest

activities.

 4. Concentrations of suspended solids were highest at

stream sites in the Osage Plains (just outside the

Highlands).

 5. From 1970 through 1990 at most stream sites in the

Ozark Plateaus Province, concentrations of

nitrogen and phosphorus forms and suspended

solids did not change substantially; this was also

true from 1975 through 1995 for streams in the

Arkansas Valley and Ouachita Mountains.

Data Sources and Methods of Analysis

Presently, 6 Federal and 15 State agencies from

Arkansas, Kansas, Missouri, and Oklahoma collect and

maintain records of the water quality of various portions

of the Assessment area (see table 2.1). Many other

local agencies and private organizations collect data

about water quality, but much of it is in paper files rather

than in computerized data bases, making it impractical

for use in this analysis. For most of the discussions of

stream water quality in the Assessment area, the

Aquatic Team used Federal or State data. Data concerning the Ozark Plateaus Province were derived from

Davis and others (1995).

Most of the available data on water quality for the

Assessment area are in three national data bases:

(1) the USDI Geological Survey’s National Water

Data Storage and Retrieval System (WATSTORE)

(Hutchison 1975, Maddy and others 1991), (2) the

EPA’s STOrage and RETrieval system (STORET)

(Hoelman 1989), and (3) the U.S. Department of

Energy’s National Uranium Resources Evaluation

(NURE) program. All data used for analyses in this

report are stored in WATSTORE.

The Aquatic Team used water quality data from 3

Federal and 4 State agencies for this analysis, representing a total of 137 water quality sampling sites (table

2.2). For surface water data, the forms of nitrogen and

phosphorus considered in this report were (1) nitrite plus

nitrate, (2) ammonia (includes both ammonium ions and

un-ionized ammonia), (3) total ammonia plus organic

nitrogen, (4) total nitrogen (the sum of the nitrogen

forms), (5) total phosphorus, and (6) orthophosphate.

Because nitrite rapidly oxidizes to nitrate in most

surface water, the team assumed that nitrite concentrations were negligible; thus they analyzed nitrite plus

nitrate instead of the individual forms. Because nitrate is

soluble in water, the team first considered dissolved

nitrite plus nitrate (filtered samples). When dissolved

nitrite plus nitrate data were unavailable, the Aquatic

Team substituted total nitrite plus nitrate (whole water

samples).

Ammonia is less soluble than nitrate, but the team

made the same substitution when dissolved data were

unavailable because samples for ammonia analyses do

not undergo rigorous digestion prior to analysis. For

surface water, total nitrogen is typically calculated using

total nitrite plus nitrate and total ammonia plus organic

nitrogen. For this analysis, the team did not substitute

dissolved ammonia plus organic nitrogen data for

missing total ammonia plus organic nitrogen data

because the Kjeldahl method used involves rigorous

sample digestion. The Aquatic Team substituted dissolved nitrite plus nitrate values in the total nitrogen

calculation when total nitrite plus nitrate data were

unavailable. The orthophosphate ion, like nitrate, is very

soluble. In cases where dissolved orthophosphate data

were unavailable, total orthophosphate data were

substituted.

Because of the substitution and combination of

certain measurements of water quality for other

56
Table 2.1—Federal and State agency sources and major water quality data collection purpose, type, and accessibility for the

Assessment area

Agency Data collection purpose, type, and accessibility

Federal

USDI National Park Service Resource assessment on National Park Service lands; data are collected seasonally in cooperation

with the USDI Geological Survey and universities; data include organic and coliform bacteria

counts; data are computerized, some in WATSTORE; some streamflow data available.

U.S. Army Corps of Engineers Resource assessment on Corps-developed projects; variety of water quality data, sometimes

collected in cooperation with other Federal agencies; data available from STORET and/or

WATSTORE.

U.S. Department of Energy National Uranium Resources Evaluation (NURE) Program; assesses uranium resources of the

Nation; data are computerized, all data are inorganic; some data available on location, depth, and

casing length of water well.

U.S. Environmental Protection Regulatory; wide variety of water quality data, sometimes collected in cooperation with State

Agency agencies; all data in STORET; information on construction of water wells and streamflow available.

USDA Forest Service Resource assessment on national forest lands; some data are computerized, some are paper files

only; data include inorganic and biological analyses, and results of water dye-tracing tests; some

streamflow information available.

USDI Geological Survey Water resources assessment and research; limited monitoring network for ground and surface

water quality; inorganics and some organics; all data are computerized in WATSTORE including

some State agency data; information available on streamflow and water wells construction.

Arkansas

Arkansas Department of Health Monitoring of public water supply system; most samples collected after municipal treatment,

although some raw water sampled; samples analyzed for inorganics, organic, radiochemical, and

biological constituents; most data in paper files, although will soon be computerized; no

streamflow data.

Arkansas Department of Regulatory monitoring of 110 surface water sites statewide; samples analyzed for inorganic

Pollution Control and compounds with some pesticide data and fish tissue analyses for trace elements and organic

Ecology compounds; data are computerized in WATSTORE and STORET; information available on

streamflow.

Arkansas Geological Geologic mapping and mineral assessment with some water resources research; data are collected

Commission in cooperation with the USDI Geological Survey and are computerized; information available on

well construction.

Kansas

Kansas Department of Health Monitoring network of surface and ground water quality originally in cooperation with the USDI

and Environment Geological Survey, but in-house since 1990; 20 years of records with virtually all data in STORET;

chemical and biological analyses for approximately 240 surface water sites statewide, about 30-40

percent have streamflow data.

Kansas Department of Monitoring of surface water quality; data include inorganic analyses and are published, but not

Wildlife and Parks computerized.

(continued)

57
Table 2.1—Federal and State agency sources and major water quality data collection purpose, type, and accessibility for the

Assessment area (continued)

Agency Data collection purpose, type, and accessibility

Kansas Geological Survey Geological investigations and limited ground water resources research; data are computerized;

information available on well construction, particularly for wells drilled after 1975.

Missouri

Missouri Department of Monitoring contaminants in fish; analysis of fish tissue for organic compounds, lead, cadmium,

Conservation and mercury; samples collected at between 75-125 sites statewide; large volume of data, only some

computerized.

Missouri Department of Health Regulatory monitoring of ground water quality; data include coliform bacteria analyses on private

wells statewide, and nitrate and pesticide analyses in west central Missouri; also some tritium

analyses; data are collected in cooperation with the USDI Geological Survey and are computerized;

information available on water well construction.

Missouri Department of Natural Regulatory and some ambient (environmental) monitoring; data include chemical, radiochemical,

Resources—Division of and microbiological analyses of community and noncommunity water supply wells; analyses of

Environmental Quality stream water quality done in cooperation with the USDI Geological Survey; surface water and

microbiological data are computerized, ground water data are being computerized; information

about construction of water wells available mostly for wells drilled after 1975.

Missouri Department of Natural Geologic and water resources research, generally site specific; inorganic and some pesticide

Resources—Division of analyses; some data are computerized, some only in paper files; information on construction of

Geology and Land Survey water wells includes drillers’ logs for about 30,000 wells statewide, some are computerized.

Oklahoma

Oklahoma Conservation Ambient monitoring, as well as prioritization of basins for cost share assistance; data include

Commission nutrients, specific conductance (a measure of the ability of water to conduct an electrical current),

pH, and dissolved oxygen, with some biological data on fish, periphyton (surface attached

organisms), and algae; data are computerized in STORET and WATSTORE.

Oklahoma Department of Monitoring ambient water quality and assessing hazardous waste sites; most data in STORET or

Environmental Quality other computerized data base; some sites are water supply systems with samples taken after

municipal treatment; ground water samples generally are raw; analyses include inorganic, and

some fish tissue, sediment, and pesticide data; some streamflow information is available; information on construction of water wells is available from the Oklahoma Water Resources Board.

Oklahoma Geological Survey All water quality work done in cooperation with the USDI Geological Survey; all data are computerized; information on well site characteristics and construction available for most sampling sites.

Oklahoma Scenic River Monitoring ambient water quality of the Illinois, Flint, and Baron Fork Rivers; analyses include

Commission nutrients, suspended solids, chloride, sulfate, hardness, turbidity, and chemical oxygen demand;

all data in STORET.

Oklahoma Water Resources Monitoring network to establish trends and set water quality standards; 300 water wells statewide;

Board all data in STORET; analyses primarily include inorganics; water well construction information

available as supplied from drillers’ logs.

58
measurements (e.g., total nitrite plus nitrate for dissolved

nitrite plus nitrate), the resulting data for a constituent

(nitrite plus nitrate, for example) often included results

of analyses performed on filtered and whole water

samples. For these constituents, the “total” and “dissolved” adjectives are not included in the following

discussions. The Aquatic Team did not combine data for

total ammonia plus organic nitrogen and total phosphorus

in surface water samples with data for filtered samples;

therefore, the “total” adjective is retained. However, the

“total” in “total nitrogen” refers to a summation of

values for the various forms of nitrogen, some of which

may be from analyses of filtered samples.

The movement of suspended sediment in streams is

an important factor in the transport and fate of chemicals in the environment. (Suspended sediment, which

can be transported in the water column or can settle to

the streambed, is particulate matter consisting of soil

and rock particles eroded from land.) The suspended

particles can absorb or adsorb nutrients, trace elements,

and organic compounds. Fecal bacteria also can be

associated with suspended sediment.

The sediment available for transport by a stream is

determined by a combination of factors including soil

type, vegetative cover, topography, land use, and the

intensity or frequency of precipitation. Overland runoff

of precipitation usually delivers sediment to streams.

Intense storms that increase stream discharge, erosion,

and resuspension of streambed sediments often create

high concentrations of suspended sediments. In addition,

row-crop agriculture, animal grazing, timber harvesting,

mining, road construction and maintenance, and urbanization can increase land erosion and create concentrations of sediment in streams. Excess suspended sediment can adversely affect the quality of surface water.

Turbid (murky or clouded) streams are aesthetically

unsatisfactory for swimming and other recreational

activities and are biologically less productive because

light cannot penetrate to drive photosynthesis by algae

and other plants. Higher than normal concentrations of

suspended sediment can affect fish populations, either

directly or indirectly, by preventing the successful

development of fish eggs and larvae or by decreasing

the available food supply (by blocking photosynthesis

Table 2.2—Summary by Federal and State agency of the number of sites,

collection methods, and frequency of surface water quality samples utilized

in this report

Number Collection Collection

Agency of sites method frequency

U.S. Army Corps of Engineers 3 GB M, D

USDI Geological Survey 63 EWI PD

USDI National Park Service 1 GB M

Arkansas Department of Pollution 67 GB PD

Control and Ecology

Kansas Department of Health 2 GB B-M, M

and Environment

Missouri Department of 0a NA NA

Natural Resources

Oklahoma Department of 7 GB M, W

Environmental Quality

Total 137b

GB = grab; M = monthly; D = daily; NA = not available; EWI = equal width increment;

PD = project dependent frequency; B-M = bimonthly; W = weekly.

a Several of the USDI Geological Survey sites were sampled in cooperation with the MO DNR.

b Includes six sites that were sampled jointly by two agencies.

59
which affects the entire food chain). Deposits of

sediment in reservoirs decrease the storage capacity for

water supply or flood control. Mechanical removal of

such sediment from water supplies is expensive.

The Aquatic Team considered both suspended

sediment and suspended solids for this report. These

two measures are not considered to be comparable

because of differences in collection and analytical

techniques. The Aquatic Team used suspended sediment data in this analysis when these data were available. When the team did use suspended solids data, they

did not compare that data directly to suspended sediment data.

The initial data set for the quality of stream surface

water examined by the Aquatic Team contained

approximately 80,000 samples for 2,300 sites for the

water years 1970 through 1990 (Ozark Plateaus

Province) and 1975 through 1995 (Arkansas Valley and

Ouachita Mountains). (A water year is defined as a 12

month period from October 1st through September 30th.

The water year is designated by the calendar year in

which it ends. For example, the 1990 water year was

from October 1, 1989 through September 30, 1990.)

Some of these 2,300 sites, particularly in the Ozark

Plateaus, were sampled by more than one agency;

therefore, the data selected by the team have the best

temporal, seasonal, or hydrologic distribution or were

collected, processed, preserved, or analyzed using

preferred techniques. The Aquatic Team applied

screening criteria (described below) to the data set,

decreasing the numbers to about 27,000 samples and

137 sites (table 2.2).

Because of the scarcity of data available for the

Arkansas Valley and the Ouachita Mountains, the team

limited screening of samples to the discarding of all but

one of multiple samples collected on the same day at a

specific site. The team performed additional screening

on data from the Ozark Plateaus and removed those

data not meeting the specified criteria. Data were

acceptable if: (1) site-specific information regarding

location, type, number, and seasonal and hydrologic

distributions of samples was available; (2) sample

collection, processing, preservation, and analytical

techniques were appropriate; and (3) quality assurance

and quality control practices were used by the agencies

that collected and analyzed samples.

Sample processing and preservation techniques are

used by many agencies to stabilize the sample so that it

retains as much of its original character as possible.

These procedures involve filtering or adding reagents to

stop biological action. Samples collected for nutrient

analysis are generally preserved with mercuric chloride

(Geological Survey’s method) or sulfuric acid (EPA’s

approved method) and then chilled, or they are preserved by chilling alone. All samples that contributed to

data sets used in this report were preserved prior to

analysis.

The methods used to analyze samples are another

important consideration. For the past decade or so, most

laboratories have used auto-analyzers to determine

presence and concentrations of nitrite, nitrate, ammonia,

phosphorus, and orthophosphate, and have used the

Kjeldahl method to determine ammonia plus organic

nitrogen (Clesceri and others 1989). The Aquatic Team

used only the period including water years 1980 through

1995 for the discussion of the conditions of stream

quality in the Assessment area. Before 1980, other

methods may have been used, potentially resulting in a

positive or negative analytical bias. Data collected

before water year 1980 are shown as part of the

discussion of long-term trends.

Treatment of censored data. Limitations in laboratory analytical techniques and equipment determine the

lower limit below which constituent concentrations

cannot be accurately determined or reported. When the

actual concentration is less than this lower limit, the

concentration is reported as less than the detection limit

or minimum reporting level of the analytical method.

Some of the data reported in this analysis as less than a

certain concentration may actually represent method

detection limits rather than minimum reporting levels. In

the following discussions, “detection limit” will be used

to describe the lower limit of an analytical method. Data

are considered “censored” if greater than 5 percent of

the total number of data values are flagged as less than

a certain detection limit or as not detected. A particular

constituent may have censored values with several

different detection limits because analytical techniques

vary among laboratories or have changed over time.

How these censored data are handled in statistical

analysis varies with each method. When dealing with

censored values, the objective is to maximize information

60
without losing statistical integrity. The specific treatment

of censored data will be discussed in the descriptions of

the individual statistical methods.

Timespan for the assessment of conditions. To

minimize the potential effects of long-term trends and

the number of changes in detection limits, the Aquatic

Team chose relatively short and recent periods to assess

current conditions of surface water in Highlands

streams: water years 1980 through 1990 (Ozark Plateaus Province) and 1985 through 1995 (Arkansas

Valley and Ouachita Mountains). This 11-year period is

short enough because (1) only in extreme cases would

long-term trends affect the overall description of current

conditions found, and (2) detection limits have been

fairly consistent throughout these 11-years, and nutrient

concentrations are frequently at or less than detection

limits.

Descriptive statistics. The Aquatic Team used

descriptive statistics to show the central tendency and

variation in the water quality data. They calculated the

minimum, maximum, 10th, 25th, 50th (median), 75th, and

90th percentiles, choosing the median to represent the

central tendency of the data because the median is less

sensitive to extreme values than the mean. The 25th and

75th percentiles provide more information on the central

tendency and with the 10th and 90th percentiles provide

information on the typical variations in the data. When

the team calculated summary statistics for individual

surface water sites, they estimated percentiles for

censored data by using a log-probability regression

procedure described by Gilliom and Helsel (1986) and

Helsel and Cohn (1988). The team did not report

estimated percentiles if fewer than five observations

higher than the detection limit existed.

The team graphically displayed distributions of

selected nutrient concentrations for surface water data

using side-by-side boxplots. A boxplot is a useful tool for

visually examining the central tendency and variation of

a group of data or for comparing two or more groups of

data (Tukey 1977).

Hypothesis tests. The Aquatic Team used the

nonparametric Kruskal-Wallis analysis-of-variance test

(Helsel and Hirsch 1992) to test for differences in the

distributions of two or more groups of data. The distributions of the groups are considered significantly

different from one another if there is a probability (P

value) of less than 5 percent (< 0.05) that the observed

difference occurs by chance.

Analysis of long-term trends. The Aquatic Team

plotted data from selected sites as time series and added

a line of central tendency or “smooth.” The smoothing

technique used is called the LOWESS (LOcally

WEighted Scatterplot Smoothing) procedure (Cleveland

1979). The purpose of smoothing is to highlight trends or

patterns that exist in the data but are difficult to see

when data are plotted as scatterplots only. Scatterplots

and LOWESS allow a visual examination of trend

patterns for sites with data available for different time

periods and illustrate patterns of similarity or variation in

constituent concentrations between two or more water

quality sites. No statistical trend tests were performed

for this report.

Spatial and temporal distributions of surface

water quality data. Data on nutrients and suspended

solids were available for more than 2,300 surface water

sites located in the Assessment area. Figure 2.1 shows

the locations of the 137 sites selected; table 2.3 shows

the names of the sites. Spatial distribution of the sites is

not uniform, because long-term sampling programs have

not been conducted in the headwaters of streams

draining several physiographic areas (e.g., the Salem

Plateau, and the St. Francois, Boston, and Ouachita

Mountains). However, the sites selected collectively

represent a wide range of the physiography and major

land uses present in the Assessment area.

A land-use type was assigned to each site based on

physiographic area and land use or proximity to a sewage treatment plant (STP). All sites have (1) drainage

basins with relatively homogeneous physiography and

land use and (2) identifiable factors influencing water

quality. The team used Geographic Information Retrieval and Analysis System (GIRAS) data (USDI GS

1990) to determine the major land uses in each basin

and found the categories “forest” and “agriculture”

predominate throughout the Assessment area. To reflect

the different agricultural practices found in the Ozark

Plateaus, “agriculture” was subdivided into “cropland,”

“pasture,” and “forest-pasture mix” (defined as greater

than one-third but less than two-thirds pasture); poultry,

cattle, and swine are commonly raised on these

pasturelands. Other sites were categorized as STP

sites because of the close proximity of STP discharges.

61
1

82

2

6 7

83

5

8

11

10

12

13

14

15

16

43

44

45 17

3 4

26

27

58

59

60

80

56 57

81

77

75

65

72 71

63

62

64

79

61

76 67

68 66 74

69

18

19

20

21

22

23

24

25

73

28

29

30

31

32 33

34

35

36

37

38

39 40

41

46 47

48 49

50

51

78

52

53

54

55

42

100

104

103

109 94 93

95

96

97

98

99

105

101 102

70

90 91

92 89

88

87 86 85

120

121

134

125

84 106

107

108

110

111

117

118

119

137

112

112

115

122

126

130

123

124

128

133

132

131

129

135

136

127

114 116

9

Missouri

Arkansas

Kansas

Oklahoma

Ozark Plateaus Province

Ouachita Province

Surface-water site

 (for site number, name,

 and location refer to table 2.3)

Aquatic study area

Physiographic province

 boundary

Physiographic section

 boundary

Figure 2.1—Locations of surface water sampling sites in the aquatic study area.

62
Site

number Site name and location

1 Little Osage River at Fulton, KS

2 Osage River above Schell City, MO

3 Sac River near Dadeville, MO

4 Little Sac River near Walnut Grove, MO

5 Pomme de Terre River near Polk, MO

6 South Grand River at Urich, MO

7 West Fork Tebo Creek near Lewis, MO

8 Niangua River at Bennett Springs, MO

9 Osage River below St.Thomas, MO

10 Big Piney River at Devil’s Elbow, MO

11 Gasconade River above Jerome, MO

12 Meramec River near Sullivan, MO

13 Bourbeuse River above Union, MO

14 Big River near Richwoods, MO

15 Meramec River near Eureka, MO

16 St. Francis River near Saco, MO

17 St. Francis River at Fisk, MO

18 West Fork White River east of Fayetteville, AR

19 White River near Goshen, AR

20 Richland Creek at Goshen, AR

21 Holman Creek near Huntsville, AR

22 White River Beaver Dam near Eureka Springs, AR

23 Osage Creek southwest of Berryville, AR

24 Osage Creek west of Berryville, AR

25 Kings River near Berryville, AR

26 James River near Wilson Creek, MO

27 James River near Boaz, MO

28 Long Creek near Denver, AR

29 White River at Table Rock Dam near Branson, MO

30 White River at Bull Shoals Dam near Flippin, AR

31 Crooked Creek at Harrison, AR

32 Crooked Creek near Harrison, AR

33 Crooked Creek at Yellville, AR

34 Buffalo River near St. Joe, AR

35 Hicks Creek near Mountain Home, AR

36 White River near Norfork, AR

37 North Fork River near Tecumseh, MO

38 North Fork River at Norfork Dam near Norfork, AR

39 White River at Calico Rock, AR

40 Mill Creek near Melbourne, AR

41 North Sylamore Creek near Fifty Six, AR

42 White River at Oil Trough, AR

43 Black River below Annapolis, MO

44 Black River at Clearwater Dam, MO

45 Black River at Poplar Bluff, MO

46 Current River at Doniphan, MO

Site name and location

47 Little Black River below Fairdealing, MO

48 Current River near Pocahontas, AR

49 Black River at Pocahontas, AR

50 South Fork Spring River at Saddle, AR

51 Spring River at Ravenden, AR

52 Eleven Point River near Bardley, MO

53 Eleven Point River near Pocahontas, AR

54 Black River at Black Rock, AR

55 Strawberry River near Smithville, AR

56 Neosho River near Parsons, KS

57 Lightning Creek near McCune, KS

58 Spring River near Waco, MO

59 Turkey Creek near Joplin, MO

60 Shoal Creek near Galena, KS

61 McKisic Creek tributary near Bentonville, AR

62 Butler Creek near Sulphur Springs, AR

63 Elk River near Tiff City, MO

64 Spavinaw Creek near Cherokee City, AR

65 Neosho River at Fort Gibson Lake, Fort Gibson, OK

66 Illinois River at Savoy, AR

67 Osage Creek near Elm Springs, AR

68 Illinois River near Siloam Springs, AR

69 Baron Fork at Dutch Mills, AR

70 Illinois River at Highway 64 Bridge, OK

71 Baron Fork at Eldon, OK

72 Illinois River near Tahlequah, OK

73 Buffalo River at wilderness boundary, AR

74 Illinois River near Watts, OK

75 Neosho River above Industrial Park, OK

76 Flint Creek near West Siloam Springs, OK

77 Neosho River near Langley, OK

78 Spring River near Thayer, MO

79 Little Sugar Creek at Caverna, MO

80 Spring River at Devils Prominade Bridge, OK

81 Neosho River near Chetopa, KS

82 Marmaton River near Fort Scott, KS

83 Osage River below Truman Dam at Warsaw, MO

84 Poteau River east of Waldron, AR

85 Poteau River northwest of Waldron, AR

86 Poteau River at Cauthron, AR

87 Poteau River at Loving, OK

88 Black Fork below Big Creek near Page, OK

89 Black Fork at Hodgen, OK

90 Fourche Maline near Red Oak, OK

91 Fourche Maline near Le Flore, OK

92 Holson Creek at Summerfield, OK

Table 2.3—Surface water sites for nutrient and suspended solids data (sites mapped in fig. 2.1)

(continued)

Site

number

63
For the Arkansas Valley and Ouachita Mountains, the

team categorized land use as “agriculture-forest mix”

(i.e., greater than one-third but less than two-thirds

agriculture).

Depending upon the agency and program, sampling

can occur on different schedules. For example, nitrite

plus nitrate samples were collected somewhat uniformly

at monthly or bimonthly intervals. The selected 83 sites

in the Ozark Plateaus represent sampling programs

conducted by Federal and State agencies and are

generally characteristic of this part of the Assessment

area. The 54 sites in the Arkansas Valley and Ouachita

Mountains were sampled as part of more variable

sampling programs. A seasonal component (e.g.,

sampling for streamflow during summer and early fall

months) at some locations resulted in additional water

quality samples.

Patterns

The Aquatic Team identified the factors affecting

concentrations of nutrients and suspended solids in

surface water by analyzing the water quality in relation

to various basin characteristics. Based on physiographic

area and category of land use, the team combined the

11 years of data for individual stream sites (see

“Timespan for the assessment of conditions” on page

61). The team considered differences in water quality

within a physiographic area that had multiple categories

of land use and between physiographic areas with

categories of “forested” or “agricultural” land uses.

Because of the availability of data for only a small group

of sites in the Boston, St. Francois, and Ouachita

Mountains, the results of these analyses may not always

be representative of widespread ambient conditions in

these physiographic areas.

Table 2.3—Surface water sites for nutrient and suspended solids data (sites mapped in fig. 2.1) (continued)

Site

number Site name and location

93 James Fork near Hackett, AR

94 Poteau River near Panama, OK

95 Mulberry River at I40 near Mulberry, AR

96 Short Mountain Creek west of Paris, AR

97 Short Mountain Creek north of Paris, AR

98 Big Piney Creek at Highway 164 near Dover, AR

99 Illinois Bayou near Dover, AR

100 Whig Creek near Dardanelle, AR

101 Petit Jean River near Booneville, AR

102 Petit Jean River near Waveland, AR

103 Dutch Creek at Shark, AR

104 Chickalah Creek near Chickalah, AR

105 White Oak Creek near Atkins, AR

106 Fourche La Fave River near Gravelly, AR

107 Fourche La Fave River near Nimrod, AR

108 South Fourche La Fave River at Hollis, AR

109 Stone Dam Creek near Conway, AR

110 Maumelle River at Williams Junction, AR

111 Ouachita River near Mount Ida, AR

112 Ouachita River near Malvern, AR

113 Ouachita River near Donaldson, AR

114 South Fork Caddo River at Fancy Hill, AR

115 Caddo River near Amity, AR

Site name and location

116 Little Missouri River near Langley, AR

117 Alum Fork Saline River near Reform, AR

118 Saline River west of Benton, AR

119 Saline River near Shaw, AR

120 Kiamichi River near Big Cedar, OK

121 Mountain Fork near Hatfield, AR

122 Rolling Fork River below DeQueen Dam, AR

123 Bear Creek near Horatio, AR

124 Little River near Horatio, AR

125 Cossatot River near Vandervoort, AR

126 Cossatot River near Umpire, AR

127 Cossatot River below Gillham Dam, AR

128 Cossatot River near Lockesburg, AR

129 Saline River near Burg, AR

130 Saline River below Dierks Dam, AR

131 Holly Creek east of Dierks, AR

132 Holly Creek at Dierks, AR

133 Saline River near Lockesburg, AR

134 Prairie Creek near Mena, AR

135 Prairie Creek at Murfreesboro, AR

136 Prairie Creek near Murfreesboro, AR

137 Hurricane Creek near Sardis, AR

Site

number

64
The analyzed nutrient forms include: (1) nitrite plus

nitrate, (2) ammonia, (3) total ammonia plus organic

nitrogen, (4) total nitrogen, (5) total phosphorus, and

(6) orthophosphate. Summary statistics of the nutrient

data for all indicator basins grouped by physiographic

area and land use are shown in table 2.4.

Nitrite plus nitrate. Nitrite plus nitrate concentrations differed significantly among samples from streams

draining basins with different land uses within seven

physiographic areas (fig. 2.2). Median concentrations at

STP sites were significantly higher than at any other

type of site except for the Ouachita Mountains. Within

the Boston Mountains and Springfield and Salem

Plateaus, nitrite plus nitrate concentrations increased

significantly with more intensive land uses (“forest”

compared to “forest-pasture mix” compared to “pasture”), indicating a strong association between percent

“pasture” and nitrite plus nitrate concentrations. With

the exception of STP sites, the highest concentrations of

nitrite plus nitrate were found in samples from streams

draining Springfield Plateau “forest-pasture mix” and

“pasture” sites, where some of the highest densities of

poultry, cattle, swine, and agricultural operations in the

Assessment area are located.

Significant differences in nitrite plus nitrate concentrations also occurred between samples from “forested

land use” and “agricultural land use” located in different

physiographic areas (fig. 2.2). Concentrations were

lowest at “forested” sites in the Springfield Plateau,

Arkansas Valley, and Ouachita Mountains. Significant

differences between “forested” sites in the Springfield

and Salem Plateaus would not be expected, but the two

basins representing Springfield Plateau “forested land

use” are 85 percent or more forested. In contrast, the

11 Salem Plateau sites are as much as 33 percent

“pasture.” Nitrite plus nitrate concentrations can be

expected to increase as forest lands are converted to

pasture. Concentrations in the forested Boston Mountains sites were higher than in the other physiographic

areas. The Salem Plateau “forest-pasture mix” sites and

the Arkansas Valley and Ouachita Mountains “agriculture-forest mix” sites had lower nitrite plus nitrate

concentrations than “cropland” sites in the Osage

Plains. All three had concentrations significantly lower

than either of the Springfield Plateau “agricultural land

uses”—“forest-pasture mix” and “pasture.”

Ammonia. Ammonia concentrations, like nitrite plus

nitrate concentrations, were significantly higher in

samples from STP sites in all of the physiographic areas

except for the Ouachita Mountains (fig. 2.3). Ammonia

concentrations for sites in the Springfield and Salem

Plateaus generally increased significantly with more

intensive land uses, with the exception of samples from

“forest-pasture mix” sites in the Springfield Plateau.

Ammonia concentrations differed significantly among

sites with different land uses in the Ouachita Mountains,

but the “agriculture-forest mix” site had a slightly higher

median than the STP sites. Ammonia concentrations in

these instances were significantly higher than those

from basins where “pasture” is the dominant land use.

Significant differences in ammonia concentrations

also occurred between samples from “forested land

use” and “agricultural” land use” located in different

physiographic areas. When comparing data about

“forested land use” among the physiographic areas of

the Assessment area, samples from the Arkansas

Valley and the Boston and Ouachita Mountains forested

sites had significantly higher ammonia concentrations

than was measured at sites in the other physiographic

areas (fig. 2.3). Most of the samples representing

Boston Mountains forest sites were collected at one

site, located in a primarily forested basin on the West

Fork White River east of Fayetteville, AR (site 18 on

table 2.3). However, there was a substantial amount of

pastureland adjacent to the stream for 15 to 20 mi

upstream of the site. In addition, an STP about 15 river

miles upstream and urban nonpoint sources also probably contributed to the higher ammonia concentrations.

Samples from “forest-pasture mix” sites in the Salem

Plateau generally had the lowest ammonia concentrations, and samples from “agriculture-forest mix” sites in

the Ouachita Mountains had the highest concentrations.

Total ammonia plus organic nitrogen. Fewer total

ammonia plus organic nitrogen data were available for

all physiographic areas in the Assessment area; therefore, fewer comparisons could be made. The patterns

for total ammonia plus organic nitrogen were not as

definite as those for nitrite plus nitrate and ammonia

(fig. 2.4). Samples of total ammonia plus organic

nitrogen from STP sites had significantly higher concentrations than samples from other sites within the same

physiographic area. Also, median concentrations at sites

65
Table 2.4—Nutrients and suspended solids measured at surface water quality sites in the aquatic study area,

by physiographic area and land use

Ammonia +

Nitrate + organic Nitrogen, Phosphorus, Ortho- Suspended

Surface water site nitrate Ammonia nitrogen, total total total phosphate solids

 - - - - - - - - - - - - - - mg/L as nitrogen - - - - - - - - - - - - - - - - - - mg/L as phosphorus - - - mg/L

Ozark Plateaus Province and part of the Osage Plains

Osage Plains

All sites

Median 0.50 0.07 — — 0.12 — 42

Minimum <0.10 <0.01 — — <0.01 — <1

Maximum 11 8.2 — — 8.7 — 2,990

Number of samples 633 628 — — 627 — 373

Cropland

Median 0.46 0.06 0.80 1.1 0.11 0.04 40

Minimum <0.10 <0.01 <0.10 0.10 <0.01 <0.01 <1

Maximum 5.5 0.51 3.0 6.8 1.2 0.19 2,990

Number of samples 514 510 229 241 510 110 262

STP

Median 0.67 0.18 — — 0.19 — 44

Minimum <0.10 <0.01 — — 0.01 — <1

Maximum 11 8.2 — — 8.7 — 2,480

Number of samples 119 118 0 0 117 0 111

Boston Mountains

All sites

Median 0.64 0.10 0.80 1.6 0.14 0.08 15

Minimum <0.10 <0.01 <0.10 0.23 <0.01 <0.01 <1

Maximum 25 18 26 32 6.8 4.9 429

Number of samples 376 340 168 165 371 367 319

Forest

Median 0.32 0.05 0.50 0.80 0.07 0.03 18

Minimum <0.10 <0.01 <0.10 0.23 0.01 <0.01 1

Maximum 6.1 2.5 3.5 9.6 0.87 0.45 316

Number of samples 125 134 55 53 124 120 121

Mix

Median 0.50 — — — 0.03 0.01 —

Minimum <0.10 0.01 0.70 0.94 <0.01 <0.01 —

Maximum 1.6 0.25 1.3 2.9 0.32 0.23 —

Number of samples 24 5 4 5 24 24 0

STP

Median 0.90 0.21 0.92 2.3 0.32 0.20 12

Minimum 0.10 <0.01 <0.10 0.46 <0.01 <0.01 <1

Maximum 25 18 26 32 6.8 4.9 429

Number of samples 227 201 109 107 223 223 198

Springfield Plateau

All sites

Median 1.5 0.04 0.35 1.6 0.10 0.06 6

Minimum <0.10 <0.01 <0.10 <0.10 <0.01 <0.01 <1

Maximum 32 15 6.5 18 14 13 480

Number of samples 2,348 2,099 999 879 2,410 1,348 2,250

Forest

Median 0.10 0.03 0.20 0.31 0.01 0.01 3

Minimum <0.10 <0.01 <0.10 <0.10 <0.01 <0.01 <1

Maximum 0.58 0.34 6.4 6.5 0.32 0.13 228

Number of samples 189 188 144 132 200 169 128

Mix

Median 1.2 0.04 0.33 1.3 0.09 0.05 5

Minimum 0.10 <0.01 <0.10 0.26 <0.01 <0.01 <1

Maximum 5.5 1.4 4.0 5.4 2.2 0.55 480

Number of samples 740 522 397 337 775 258 704

(continued)

66
Table 2.4—Nutrients and suspended solids measured at surface water quality sites in the aquatic study area,

by physiographic area and land use (continued)

Ammonia +

Nitrate + organic Nitrogen, Phosphorus, Ortho- Suspended

Surface water site nitrate Ammonia nitrogen, total total total phosphate solids

 - - - - - - - - - - - - - - mg/L as nitrogen - - - - - - - - - - - - - - - - - - mg/L as phosphorus - - - mg/L

Ozark Plateaus Province and part of the Osage Plains (continued)

Pasture

Median 1.6 0.04 0.40 2.1 0.08 0.06 8

Minimum 0.10 <0.01 <0.10 0.60 <0.01 <0.01 <1

Maximum 32 1.6 2.8 4.7 3.4 1.7 480

Number of samples 732 686 318 276 752 515 781

STP

Median 2.1 0.06 0.52 3.0 0.62 0.40 7

Minimum <0.10 <0.01 <0.10 1.0 <0.01 <0.01 <1

Maximum 20 15 6.5 18 14 13 370

Number of samples 687 703 140 134 683 406 637

Salem Plateau

All sites

Median 0.38 0.03 0.46 1.0 0.03 0.02 7

Minimum <0.10 <0.01 <0.10 <0.20 <0.01 <0.01 1

Maximum 18 8.0 9.0 19 7.2 5.7 523

Number of samples 1,751 1,799 385 370 1,854 1,124 1,733

Forest

Median 0.30 0.02 0.40 0.70 0.02 0.01 6

Minimum <0.10 <0.01 <0.10 <0.20 <0.01 <0.01 1

Maximum 6.5 0.63 3.1 3.2 0.99 0.19 288

Number of samples 656 615 156 155 651 189 582

Mix

Median 0.37 0.03 0.38 0.72 0.03 0.01 8

Minimum <0.10 <0.01 <0.10 0.30 <0.01 <0.01 1

Maximum 1.5 0.87 4.0 4.3 1.9 1.7 523

Number of samples 784 867 86 86 872 621 795

STP

Median 0.94 0.08 0.56 1.6 0.11 0.07 6

Minimum <0.10 <0.01 <0.10 0.62 <0.01 <0.01 1

Maximum 18 8.0 9.0 19 7.2 5.7 263

Number of samples 311 317 143 129 331 314 356

St. Francois Mountains

Forest (All sites)

Median 0.20 0.02 — — 0.04 — 5

Minimum <0.10 <0.01 — — <0.01 — <1

Maximum 1.3 0.44 — — 0.31 — 38

Number of samples 66 66 0 0 66 0 65

Ouachita Province

Arkansas Valley

All sites

Median 0.12 0.12 0.70 1.10 0.05 — 44

Minimum <0.10 <0.01 <0.10 0.14 <0.01 — <1

Maximum 52 52 32 54 28.5 — 618

Number of samples 1,570 2,017 986 610 1,564 — 2,197

Forest

Median 0.08 0.08 0.40 0.59 0.04 0.02 5

Minimum <0.10 <0.01 <0.10 0.14 <0.01 <0.01 <1

Maximum 1.1 1.2 4.1 4.2 2.0 0.13 618

Number of samples 837 1,149 353 143 1,063 152 1,151

(continued)

67
Table 2.4—Nutrients and suspended solids measured at surface water quality sites in the aquatic study area,

by physiographic area and land use (continued)

Ammonia +

Nitrate + organic Nitrogen, Phosphorus, Ortho- Suspended

Surface water site nitrate Ammonia nitrogen, total total total phosphate solids

 - - - - - - - - - - - - - - mg/L as nitrogen - - - - - - - - - - - - - - - - - - mg/L as phosphorus - - - mg/L

Ouachita Province (continued)

Mix

Median 0.1 0.1 0.60 0.80 0.06 — 14

Minimum <0.10 <0.01 <0.10 0.15 <0.01 — 2

Maximum 3.7 3.7 6.6 8.3 8.5 — 479

Number of samples 316 365 161 127 320 — 503

Agriculture

Median 0.11 0.12 1.0 1.3 — — 22

Minimum <0.10 <0.01 0.40 0.54 — — 1

Maximum 0.69 0.69 32 25 — — 306

Number of samples 94 111 81 56 — — 124

STP

Median 0.78 0.78 1.3 4.5 0.64 — 14

Minimum <0.10 <0.01 <0.10 0.31 <0.01 — 1

Maximum 52 52 32 54 28.5 — 280

Number of samples 323 392 391 284 181 — 419

Ouachita Mountains

All sites

Median 0.13 0.13 0.50 0.83 0.04 — 5

Minimum <0.10 <0.01 <0.10 0.13 <0.01 — <1

Maximum 7 7 19 19 8.3 — 3,230

Number of samples 1,846 2,216 888 692 2,209 — 1,934

Forest

Median 0.10 0.09 0.41 0.73 0.04 0.01 4

Minimum <0.10 <0.01 <0.10 0.13 <0.01 <0.01 <1

Maximum 1.6 1.6 19 19 6.4 0.04 3,230

Number of samples 1,186 1,438 597 443 1,498 18 1,195

Mix

Median 0.21 0.2 0.20 0.85 0.05 — 6

Minimum <0.10 <0.01 <0.10 0.25 <0.01 — 1

Maximum 1 1 0.80 2.7 0.47 — 95

Number of samples 153 185 19 14 277 — 177

STP

Median 0.19 0.19 0.75 1.4 0.06 — 8

Minimum <0.10 <0.01 <0.10 0.18 <0.01 — <1

Maximum 7 7 12 15 8.3 — 360

Number of samples 507 593 272 235 434 — 562

mg/L = milligrams per liter; — = insufficient data available; STP = sewage treatment plant; Mix = forest-pasture mix.

in forested basins within the Springfield and Salem

Plateaus and Arkansas Valley were equal to or significantly lower than concentrations at sites in basins with

“agriculture” or “agriculture-forest mix” land uses.

Figure 2.4 indicates that the Springfield Plateau had

the lowest concentrations of total ammonia plus organic

nitrogen in samples from basins with “forest” land use

and the Boston Mountains had the highest concentrations. Total ammonia plus organic nitrogen concentrations differed significantly among samples from basins

with “agricultural land use” in the Arkansas Valley and

Ouachita Mountains. Samples from the Springfield

“forest-pasture mix” and Ouachita Mountains “agriculture-forest mix” had the lowest total ammonia plus

organic nitrogen concentrations and samples from the

Arkansas Valley had the highest concentrations. Total

ammonia plus organic nitrogen concentrations did not

differ significantly among samples from basins with

“agricultural land use” in the Springfield and Salem

Plateaus, but all of these constituents were significantly

lower than concentrations in samples collected from

streams in the Osage Plains “cropland” areas.

68
Figure 2.2—Statistical distribution of nitrite plus nitrate concentrations at surface water sites for water years 1980 through 1990 (Ozark

Plateaus) and 1985 through 1995 (Arkansas Valley and Ouachita Mountains) (modified from Davis and others 1995).

a A

p<0.05

b

(316) (94) (153)

(94)

(1,186)

STP STP

M1

AV OM

(837) (1,186)

OM

M1 A

AV

p<0.05

BM SP SA SF

10

1

0.1

0.01

Forested land use by physiographic area

(125) (189) (656) (66)

c c a b

DL

p<0.05

CMP M

OP SP SP SA

Agricultural land use by physiographic area

(514) (740) (732) (784)

b

c

d

a

DL

d e e f

(837) (507)

(316)

M1 A

AV OM

a

p<0.05

e

(66) (323)

SA

M M1 FF F

Land use by physiographic area

p<0.05 p<0.05 p<0.05 p<0.05

b

b

c

c

c

d

C STP STP F F M MP STP F STP

OP BM SP SF

10

1

0.1

0.01

(514) (119) (125) (24) (227) (189) (740) (732) (687) (656) (784) (311)

(153)

a a

b b DL

a a a a c b

10

1

0.1

0.01

Milligrams per liter

Milligrams per liter

Milligrams per liter

P-value—probability that observed difference occurs by chance. Probabilities less than

 5 percent (<0.05) are assumed to be significant.

Number in parentheses—number of analyses included in computation of percentiles.

(66)

p<0.05

90th percentile

75th percentile

50th percentile (median)

25th percentile

10th percentile

Within a compared group, distributions

 associated with the same letter are

 not significantly (p<0.05) different

a

DL Detection limit

Physiographic area

OP

BM

SP

SA

SF

AV

OM

Osage Plains

Boston Mountains

Springfield Plateau

Salem Plateau

St. Francois Mountains

Arkansas Valley

Ouachita Mountains

Land use

A

F

M

M1

P

C

STP

Agriculture

Forest

Forest-pasture mix

Agriculture-forest mix

Pasture

Cropland

Sewage treatment plant

69
Figure 2.3—Statistical distribution of ammonia concentrations at surface water sites for water years 1980 through 1990 (Ozark Plateaus)

and 1985 through 1995 (Arkansas Valley and Ouachita Mountains) (modified from Davis and others 1995).

(392) (185)

M1

(615) (66) (522) (686) (867)

d

D

g

f

M1

AV OM OM

M1 A

AV

p<0.05

CMP M

OP SP SP SA

(510) (365) (111) (185)

DL

c b a

e

p<0.05

BM SP SA SF

(134) (188) (1,149) (1,438)

DL

10

1

0.1

0.01

0.001

aaa

c

b d

p<0.05 p<0.05

(703) (615) (867) (317) (66)

A F M1

AV OM

F

p<0.05 p<0.05 p<0.05 p<0.05

CF F M M F F M P

OP BM SP SA SF

(510) (118) (134) (5) (201) (188) (522) (686) (1,149) (365) (111) (1,438) (593)

DL

b b

c

a a ab d

10

1

0.1

0.01

0.001

a c b

b

a a a a

b

c

STP STP STP STP STP STP

Forested land use by physiographic area Agricultural land use by physiographic area

Land use by physiographic area

P-value—probability that observed difference occurs by chance. Probabilities less than

 5 percent (<0.05) are assumed to be significant.

Number in parentheses—number of analyses included in computation of percentiles.

(66)

p<0.05

90th percentile

75th percentile

50th percentile (median)

25th percentile

10th percentile

Within a compared group, distributions

 associated with the same letter are

 not significantly (p<0.05) different

a

DL Detection limit

Physiographic area

OP

BM

SP

SA

SF

AV

OM

Osage Plains

Boston Mountains

Springfield Plateau

Salem Plateau

St. Francois Mountains

Arkansas Valley

Ouachita Mountains

Land use

A

F

M

M1

P

C

STP

Agriculture

Forest

Forest-pasture mix

Agriculture-forest mix

Pasture

Cropland

Sewage treatment plant

10

1

0.1

0.01

0.001

Milligrams per literMilligrams per liter

Milligrams per liter

70
Figure 2.4—Statistical distribution of total ammonia plus organic nitrogen concentrations at surface water sites for water years 1980

through 1990 (Ozark Plateaus) and 1985 through 1995 (Arkansas Valley and Ouachita Mountains) (modified from Davis and others

1995).

c

b

c

(391) (272)

p<0.05

F

b

b

c

M1

AV OM OM

M1 A

AV

p<0.05

CMPM

OP SP SP SA

(229) (397) (318) (86)

DL

a a

c

a

(353) (597) (161) (81) (19)

p<0.05

BM SP SA SF

(55) (144) (156) (0)

DL

10

1

0.1

0.01

c a b

d

a b

p<0.05 p<0.05

(140) (156) (86) (143) (0) (353) (161) (81) (597) (19)

a

A M1

AV OM

F M1

p<0.05 p<0.05

CF F M M F F M P

OP BM SP SA SF

(229) (0) (55) (4) (109) (144) (397) (318)

DL

10

1

0.1

0.01

b

b

a a b c

a

b a

d a

STP STP STP STP STP STP

10

1

0.1

0.01

Forested land use by physiographic area Agricultural land use by physiographic area

Land use by physiographic area

P-value—probability that observed difference occurs by chance. Probabilities less than

 5 percent (<0.05) are assumed to be significant.

Number in parentheses—number of analyses included in computation of percentiles.

(66)

p<0.05

90th percentile

75th percentile

50th percentile (median)

25th percentile

10th percentile

Within a compared group, distributions

 associated with the same letter are

 not significantly (p<0.05) different

a

DL Detection limit

Physiographic area

OP

BM

SP

SA

SF

AV

OM

Osage Plains

Boston Mountains

Springfield Plateau

Salem Plateau

St. Francois Mountains

Arkansas Valley

Ouachita Mountains

Land use

A

F

M

M1

P

C

STP

Agriculture

Forest

Forest-pasture mix

Agriculture-forest mix

Pasture

Cropland

Sewage treatment plant

Milligrams per liter

Milligrams per liter

Milligrams per liter

71
Total nitrogen. The best indicator of nitrogen loads

in a stream is the total nitrogen concentration, which is

the sum of all nitrogen forms (nitrite, nitrate, ammonia,

and organic nitrogen). Total nitrogen also is the preferred measure to use for comparisons between land

uses and physiographic areas. However, as with total

ammonia and organic nitrogen, fewer total nitrogen

analyses were available from monitoring agencies and

organizations. Fewer analyses were available because

total nitrogen generally is a calculated value and thus

requires values for all the various forms that contribute

to total nitrogen concentrations. Because total ammonia

plus organic nitrogen was not determined for many of

the samples, total nitrogen values could not be calculated for all samples.

Total nitrogen concentrations differed significantly

among samples from streams draining basins with

different land uses within five physiographic areas.

Median concentrations at STP sites were significantly

higher than at any other type of site (fig. 2.5). Within the

Springfield Plateau, total nitrogen concentrations

increased significantly with more intensive land uses

(“forest” compared to “forest-pasture mix” to

“pasture”) and in the Arkansas Valley and Ouachita

Mountains (“agriculture-forest mix” compared to

“agriculture”). For samples from forested basins, the

pattern with nitrite plus nitrate and total ammonia plus

organic nitrogen was repeated.

Within “agricultural land use,” streams in Salem

Plateau “forest-pasture mix” sites had the lowest total

nitrogen concentrations, whereas streams in the Springfield Plateau “pasture” and Arkansas Valley “agriculture” sites had the highest concentrations (fig. 2.5). In

previous comparisons between samples collected from

streams in agricultural areas in the Osage Plains and

Springfield Plateau, samples from the Osage Plains

“cropland” sites had the lowest nitrite plus nitrate

concentrations and the highest ammonia and total

ammonia plus organic nitrogen concentrations. Total

nitrogen concentrations in the Osage Plains were

significantly higher than in the Salem Plateau “forestpasture mix,” Arkansas Valley, and Ouachita Mountain

“agriculture-forest mix” sites but lower than either of

the Springfield Plateau “forest-pasture mix and pasture”

sites or Arkansas Valley “agricultural” Sites.

Total phosphorus. Total phosphorus concentrations

include phosphorus in solution and adsorbed to sediment

particles. Total phosphorus concentrations differed

significantly between streams sampled in different landuse settings in seven physiographic areas of the Assessment area (fig. 2.6). As with the various nitrogen forms,

concentrations at STP sites were significantly higher

than at sites with other land uses. Within the Springfield

Plateau, total phosphorus concentrations at sites in

“forested land use” basins were significantly lower than

concentrations at sites in “agricultural land use” basins.

This difference did not occur in the Salem Plateau.

Within the Arkansas Valley, total phosphorus concentrations at sites in “forested” basins were significantly

lower than concentrations at sites in basins with “agriculture-forest mix.”

Significant differences in total phosphorus concentrations in different physiographic areas in the Assessment

area also occurred in samples from “forested land use”

and “agricultural land use” (fig. 2.6). Concentrations

were lowest from streams in forested parts of the

Springfield Plateau, Arkansas Valley, and Ouachita

Mountains. Total phosphorus concentrations in samples

from the forested Boston Mountains probably were

higher compared to the other physiographic areas

because of the adjacent pastureland and the STP

located upstream from one of the sites. Within “agricultural land use” basins, the Salem Plateau “forest-pasture

mix” sites had the lowest total phosphorus concentrations and the Osage Plain “cropland” sites had the

highest concentrations.

Orthophosphate. Orthophosphate is the most

common phosphorus ion detected in solution in natural

waters. Agencies do not routinely carry out orthophosphate analysis, and consequently fewer data were

available than for total phosphorus. Orthophosphate

concentrations nonetheless had virtually the same pattern

as concentrations of total phosphorus for various land

uses within the physiographic areas (fig. 2.7), except that

concentrations from Springfield Plateau “pasture”

streams were significantly higher than those from the

“forest-pasture mix” streams in the Springfield Plateau.

Patterns similar to those for total phosphorus were

also seen for orthophosphate concentrations from

“forested land use” and “agricultural land use” settings

among the Ozark Plateaus physiographic areas (fig.

2.7). An exception is that concentrations for “cropland”

streams in the Osage Plains were significantly lower

than those from either of the agricultural land uses in the

72
Figure 2.5—Statistical distribution of total nitrogen concentrations at surface water sites for water years 1980 through 1990 (Ozark

Plateaus) and 1985 through 1995 (Arkansas Valley and Ouachita Mountains) (modified from Davis and others 1995).

b a

a

c

F

p<0.05

(284) (235)

c

a b

a

M1

AV OM OM

M1 A

AV

p<0.05

BM SP SA SF

(53) (132) (155) (0)

10

100

1

0.1

b

a

p<0.05

C M PM

OP SP SP SA

(241) (337) (276) (86)

d

c

b a

(143) (127) (56) (443) (14)

d

a b

(134) (155) (86) (129) (0) (143) (127) (56) (14) (443)

p<0.05

b

A M1

AV OM

F M1

p<0.05 p<0.05 p<0.05

CF F M M F F M P

OP BM SP SF SA

(241) (0) (53) (5) (107) (132) (337) (276)

10

100

1

0.1

b b c

d

a a

a

a

e

d

STP STP STP STP STP STP

10

100

1

0.1

Forested land use by physiographic area Agricultural land use by physiographic area

Land use by physiographic area

P-value—probability that observed difference occurs by chance. Probabilities less than

 5 percent (<0.05) are assumed to be significant.

Number in parentheses—number of analyses included in computation of percentiles.

(66)

p<0.05

90th percentile

75th percentile

50th percentile (median)

25th percentile

10th percentile

Within a compared group, distributions

 associated with the same letter are

 not significantly (p<0.05) different

a

DL Detection limit

Physiographic area

OP

BM

SP

SA

SF

AV

OM

Osage Plains

Boston Mountains

Springfield Plateau

Salem Plateau

St. Francois Mountains

Arkansas Valley

Ouachita Mountains

Land use

A

F

M

M1

P

C

STP

Agriculture

Forest

Forest-pasture mix

Agriculture-forest mix

Pasture

Cropland

Sewage treatment plant

Milligrams per liter

Milligrams per liter

Milligrams per liter

73
Figure 2.6—Statistical distribution of total phosphorus concentrations at surface water sites for water years 1980 through 1990 (Ozark

Plateaus) and 1985 through 1995 (Arkansas Valley and Ouachita Mountains) (modified from Davis and others 1995).

F

(1,498) (434)

c

c d

M1

AV OM OM

M1 A

AV

DL

p<0.05

CM PM

OP SP SP SA

(510) (775) (752) (872)

b c d

b a

OP

(320) (1,063) (0) (1,498) (277)

DL

p<0.05

BM SP SA SF

(124) (200) (651) (66)

a b d

c

10

1

0.1

0.01

0.001

b

(1,063) (320) (0) (181) (277)

p<0.05 p<0.05

(683) (651) (872) (331) (66)

b

AV

A M1

OM

F M1

DL

p<0.05 p<0.05 p<0.05 p<0.05

CF F M M F F M P

BM SP SF SA

(510) (117) (124) (24) (223) (200) (775) (752)

c b

b c a b

a a a a b

10

1

0.1

0.01

0.001

a

e e

a b a

STP STP STP STP STP STP

Forested land use by physiographic area Agricultural land use by physiographic area

Land use by physiographic area

P-value—probability that observed difference occurs by chance. Probabilities less than

 5 percent (<0.05) are assumed to be significant.

Number in parentheses—number of analyses included in computation of percentiles.

(66)

p<0.05

90th percentile

75th percentile

50th percentile (median)

25th percentile

10th percentile

Within a compared group, distributions

 associated with the same letter are

 not significantly (p<0.05) different

a

DL Detection limit

Physiographic area

OP

BM

SP

SA

SF

AV

OM

Osage Plains

Boston Mountains

Springfield Plateau

Salem Plateau

St. Francois Mountains

Arkansas Valley

Ouachita Mountains

Land use

A

F

M

M1

P

C

STP

Agriculture

Forest

Forest-pasture mix

Agriculture-forest mix

Pasture

Cropland

Sewage treatment plant

10

1

0.1

0.01

0.001

Milligrams per liter

Milligrams per liter

Milligrams per liter

74
Figure 2.7—Statistical distribution of orthophosphate concentrations at surface water sites for water years 1980 through 1990 (Ozark

Plateaus) and 1985 through 1995 (Arkansas Valley and Ouachita Mountains) (modified from Davis and others 1995).

(0) (0)

F

d

B

M1

AV OM OM

M1 A

OP SP SP SA AV

DL

p<0.05

CM P M

(110) (258) (515) (621)

bc a

DL

p<0.05

BM SP SA SF

(120) (169) (189) (0) 10

1

0.1

0.01

0.001

c a

(152) (18) (0) (0) (0)

(152) (0) (18) (0) (0)

A

(0)

A M1

AV OM

F M1

0.001

DL

p<0.05 p<0.05 p<0.05

CF F M M F F M P

OP BM SP SF SA

(110) (0) (120) (24) (223) (169) (258) (515) (406) (189) (621) (314)

c

c d

10

1

0.1

0.01 b b aa a a b

d b

STP STP STP STP STP STP

10

1

0.1

0.01

0.001

Forested land use by physiographic area Agricultural land use by physiographic area

Land use by physiographic area

P-value—probability that observed difference occurs by chance. Probabilities less than

 5 percent (<0.05) are assumed to be significant.

Number in parentheses—number of analyses included in computation of percentiles.

(66)

p<0.05

90th percentile

75th percentile

50th percentile (median)

25th percentile

10th percentile

Within a compared group, distributions

 associated with the same letter are

 not significantly (p<0.05) different

a

DL Detection limit

Physiographic area

OP

BM

SP

SA

SF

AV

OM

Osage Plains

Boston Mountains

Springfield Plateau

Salem Plateau

St. Francois Mountains

Arkansas Valley

Ouachita Mountains

Land use

A

F

M

M1

P

C

STP

Agriculture

Forest

Forest-pasture mix

Agriculture-forest mix

Pasture

Cropland

Sewage treatment plant

Milligrams per liter

Milligrams per liter

Milligrams per liter

75
Springfield Plateau. These results support the idea that

much of the phosphorus in the Osage Plains “cropland”

streams was associated with sediment particles,

whereas much of the phosphorus in the Springfield

Plateau “forest-pasture mix” and “pasture” streams

was in solution as orthophosphate.

Suspended sediment and suspended solids.

Suspended sediment data are considered more accurate

than suspended solids data as indicators of actual

stream concentrations of inorganic material because of

differences in collection and analytical methods. However, only 26 of the 137 sites had suspended sediment

data, so the Aquatic Team used suspended solids data

for this report.

Concentrations of suspended solids were highest in the

Osage Plains because of easily erodible soils and intensive field- and row-crop agriculture (fig. 2.8). The slightly

higher concentrations in the Boston Mountains, as

compared to the Springfield and Salem Plateaus and St.

Francois Mountains, may be because data were available

for only a small group of possibly unrepresentative sites in

the Boston Mountains. Concentrations of suspended

solids concentrations differed significantly among samples

from different land uses in the Springfield and Salem

Plateaus; concentrations increased with more intensive

land uses (“forest” compared to “forest-pasture mix”

compared to “pasture”). In the Arkansas Valley and

Ouachita Mountains, concentrations of suspended solids

in basins with “agricultural land use” were significantly

higher than concentrations in forested basins. Concentrations in the samples from STP sites are most likely related

to land uses in the basin and not to STP effluents.

Significant differences in concentrations of suspended solids in different physiographic areas of the

Assessment area also occurred among samples from

“forested land use” and “agricultural land use” (fig.

2.8). Concentrations were significantly higher at “forested” sites in the Salem Plateau; St. Francois, Boston,

and Ouachita Mountains; and Arkansas Valley than in

the Springfield Plateau. Concentrations of suspended

solids in samples collected at Springfield Plateau

“pasture” sites, Arkansas Valley “agriculture” and

“agriculture-forest mix” sites, and at Salem Plateau

“forest-pasture mix” sites were significantly higher than

the concentrations in samples collected at Springfield

Plateau “forest-pasture mix” sites.

Trends

In addition to the previously discussed water quality

patterns, the analysis of long-term trends provides

another method to assess water quality. The following

section describes changes in the quality of surface

water during water years 1970 through 1990 (Ozark

Plateaus) and 1975 through 1995 (Arkansas Valley and

Ouachita Mountains).

Water quality trends over time have been a subject of

a number of investigations of streams in the Assessment

area (AR DPCE 1980, 1984, 1986, 1992; KS DHE

1988; Brown and others 1991; Mott 1991; Davis and

Schumacher 1992; Petersen 1992; Davis and Howland

1993; Kenney and Snethen 1993; Kurklin and Jennings

1993; Petersen and others 1993; Yu and Zou 1993; Ford

1992; and Wright 1994).

Because of differing trend analysis methods, periods

of time, and sampling station densities used in these

various investigations, it is difficult to make generalizations and comparisons that would apply to the entire

Assessment area. For example, most of the sites for

which data have been analyzed for trends are in Arkansas, southwestern Missouri, and the Illinois River Basin

in northeastern Oklahoma. Nonetheless, it appears that

concentrations of nitrite plus nitrate, phosphorus, and

orthophosphate have increased at a disproportionately

higher number of sites in northwestern Arkansas,

northeastern Oklahoma, and southwestern Missouri than

in the study area as a whole. Statistically significant

downward trends in total phosphorus concentrations

have occurred at several sites in the Spring River Basin

of southwestern Missouri. The downward trends at

most of these sites in the Spring River Basin can be

attributed to the aging of two large phospho-gypsum

waste piles, which has resulted in decreasing phosphorus concentrations in the leachate from the sites (Davis

and Schumacher 1992). In Arkansas, where most of the

sites are located for which the data have been analyzed

(Petersen 1992), about one-third of the sites had

downward trends in total ammonia concentrations.

Apparent trends can be caused not only by changes

in ambient concentrations but also by changes in field

and laboratory methods. For example, Alexander and

others (1993) studied quality assurance records and

found that a higher positive bias existed for ammonia,

76
Figure 2.8—Statistical distribution of suspended solids concentrations at surface water sites for water years 1980 through 1990 (Ozark

Plateaus) and 1985 through 1995 (Arkansas Valley and Ouachita Mountains) (modified from Davis and others 1995).

(177) (562)

F

b

d

b

a b

M1

AV OM OM

M1 A

BM SP SA SF AV

p<0.05

(121) (128) (582) (65)

c

DL

1,000

10

100

1

0.1

a b d

p<0.05

CMPM

OP SP SP SA

(262) (704) (781) (795)

c

b DL

d

a

OP BM

(1,151) (1,195) (503) (124) (177)

b b

c

(65) (1,151) (503) (124) (419) (1,195)

p<0.05 p<0.05

a

c

A M1

AV OM

F M1

SP SA SF

p=0.66 p<0.05 p<0.05 p<0.05

c c

CF F M M F F M P

1,000

10

100

1

0.1

(262) (111) (121) (0) (198) (128) (704) (781) (637) (582) (795) (356)

a

a a

b

b DL

a a b

b e

a a

STP STP STP STP STP STP

Forested land use by physiographic area Agricultural land use by physiographic area

Land use by physiographic area

1,000

10

100

1

0.1

Milligrams per liter

Milligrams per liter

Milligrams per liter

P-value—probability that observed difference occurs by chance. Probabilities less than

 5 percent (<0.05) are assumed to be significant.

Number in parentheses—number of analyses included in computation of percentiles.

(66)

p<0.05

90th percentile

75th percentile

50th percentile (median)

25th percentile

10th percentile

Within a compared group, distributions

 associated with the same letter are

 not significantly (p<0.05) different

a

DL Detection limit

Physiographic area

OP

BM

SP

SA

SF

AV

OM

Osage Plains

Boston Mountains

Springfield Plateau

Salem Plateau

St. Francois Mountains

Arkansas Valley

Ouachita Mountains

Land use

A

F

M

M1

P

C

STP

Agriculture

Forest

Forest-pasture mix

Agriculture-forest mix

Pasture

Cropland

Sewage treatment plant

77
ammonia plus organic nitrogen, and phosphorus in the

early 1980’s compared to recent periods. Airborne

ammonia contamination in the laboratory may be one

cause; the source of the phosphorus contamination is

unknown. Improvements in field and laboratory methods

that decrease the amount of positive bias would create a

trend analysis that indicates a greater downward trend

than actually occurred. In addition, a change in laboratory methods at the Arkansas Department of Pollution

Control and Ecology for analysis of nitrite, nitrate,

ammonia, and total phosphorus occurred in March 1977

(Thompson 1990). Because other monitoring agencies

also changed laboratory and field methods between

1970 and 1990, these changes must be considered in

any analyses of time trends when using that data.

The Aquatic Team selected 38 sites for subsequent

examination of changes in water quality for water years

1970 through 1990 and 1975 through 1995 (table 2.5).

The team based site selection primarily on the length of

time for which data were available. Sites with the

longest continuous periods of data coverage for the

selected constituents of interest were chosen. Some

chosen sites have little data for one or more of the

constituents. The Aquatic Team did not include sites

that they considered were substantially affected by STP

discharges or that were immediately downstream of

reservoirs.

Available water quality data (concentrations of nitrite

plus nitrate, ammonia, total ammonia plus organic

nitrogen, total phosphorus, orthophosphate, suspended

sediment, and suspended solids) for water years 1970

through 1990 (Ozark Plateaus) and 1975 through 1995

(Arkansas Valley and Ouachita Mountains) were plotted

for all 38 sites. The Aquatic Team used the LOWESS

procedure to draw an “inferred concentration trend

line” on plots. To avoid misrepresenting the data, this

procedure does not draw a concentration trend line

when the proportion of censored values is high. Therefore, lines were not drawn on some plots.

Rather than including plots for all 38 sites in this

report, the Aquatic Team selected a group of sites

representative of most physiographic areas, land uses,

and collecting agencies For several sites the higher

concentrations were not plotted, however the team

included all data for a site in the calculations used to

draw the inferred concentration trend lines.

No statistical tests for trends were performed for

this report: therefore, the Aquatic Team subjectively

determined the decreasing or increasing trends mentioned in the following sections by inspection of the

plots of concentration for all 38 sites. Factors not

always considered include laboratory and field method

changes and the effects of streamflow on constituent

concentrations. The team also inspected plots of

concentrations adjusted for streamflow (Helsel and

Hirsch 1992) and, in general, determined that the “flowadjusted concentration trend lines” were similar to the

concentration trend lines. However, because a substantially lower number of sites had sufficient streamflow

data available, the flow-adjusted data are not shown.

Nitrogen. The concentrations of most forms of

nitrogen did not increase between water years 1970

through 1990 or 1975 through 1995, yet nitrogen fertilizer application rates substantially increased between

1965 and 1985 in all of the major river basins of the

Assessment area. A complete discussion of nitrogen

fertilizer can be found in Chapter 4.

Concentrations of nitrite plus nitrate did not change

substantially at most sites investigated (e.g., sites 1 and

53 in fig. 2.9). However, decreases occurred at most

sites in the Osage Plains (sites 1, 2, 7, 56, and 81). Data

indicate increases occurred at some sites in the Springfield Plateau (sites 64, 66, and 69), but the causes of

these changes are unknown. The Aquatic Team considered none of the sites to be substantially affected by

discharges from STP’s, even though several of the sites

(2, 9, 15, 56, 64, 66, 80, and 81) are downstream from

STP’s. The decreases at sites in the Osage Plains may

be the result of some change in agricultural practices.

Table 2.5— Sampling stations for nutrient and suspended

solids examined for long-term changes in water quality

Physiographic area Site numbers (fig. 2.1 and table 2.3)

Springfield Plateau 26, 34, 41, 60, 63, 64, 66, 69, 71, 72

Salem Plateau 10, 11, 12, 23, 33, 45, 50, 51, 53, 55

Boston Mountains 18, 20

St. Francois Mountains 16

Osage Plains 1, 2, 7, 56, 57, 81

Arkansas Valley 87, 97, 101, 105, 106

Ouachita Mountains 111, 113, 118, 125

78
Figure 2.9—Concentrations of nitrite plus nitrate for water years 1970 through 1990 (Ozark Plateaus) and 1975

through 1995 (Arkansas Valley and Ouachita Mountains) at selected surface water sites.

Water year

Detected value

Censored value

Inferred concentration

 trend line

1970 1975 1980 1985 1990

Milligrams per liter

0

Site 56

Osage Plains cropland

0

Site 1

Osage Plains cropland

0

Site 18

Boston Mountains forest

0

Site 53

Salem mix

0

Site 12

Salem forest

0

Site 72

Springfield mix

0

Site 63

Springfield mix

0

2.5

2.5

2.5

2.5

2.5

2.5

2.5

2.5

Site 41

Springfield forest

1975 1980 1985 1990

0

0

0

0

0

2.5

2.5

2.5

2.5

2.5

 

 

 

 

 

 

Site 105

Arkansas Valley agriculture

Site 106

Arkansas Valley forest

Site 101

Arkansas Valley mix

Site 111

Ouachita Mountains forest

Site 113

Ouachita Mountains mix

1995

Ozark Plateaus

Arkansas Valley

and

Ouachita Mountains

Milligrams per liter

79
The sites in the Springfield Plateau, where concentrations of nitrite and nitrate appear to have increased, are

in drainage basins with substantial amounts of agricultural activity.

Concentrations of ammonia decreased at several sites

(fig. 2.10). Many of these decreases were relatively

small and occurred in concentrations that were near the

detection or reporting limits near which analytical

variance may be greater. Decreases occurred at all of

the sites in the Osage Plains (sites 1, 2, 7, 56, 57, and 81)

and at four or more sites in the Salem Plateau (sites 50,

51, 53, and 55). The causes of these decreases in

concentration are unknown. Although the team did not

consider these sites to be substantially affected by STP

discharges, some are downstream from STP’s that might

be affecting concentrations enough to contribute to these

changes in water quality by reducing ammonia. Some

sites (1, 7, 50, 53, 55, and 57) are in agricultural basins

and are not downstream from STP’s. Most sites in the

Salem Plateau showing decreases are sampled by the

Arkansas Department of Pollution Control and Ecology

(sites 50, 51, 53, and 55) and began showing decreasing

concentrations in the late 1970’s. Differing field or

laboratory methods of the two agencies (such as the

early 1980’s bias of Geological Survey data) may

partially explain the decreases in reported concentrations.

Concentrations of total ammonia plus organic nitrogen seem to have decreased at a few sites and increased at others (fig. 2.11). Most of these decreases

were in the Springfield Plateau (sites 34, 64, 71, and 72)

and Osage Plains (sites 2, 7, and 56). Concentrations of

total ammonia plus organic nitrogen seem to have

increased at site 101 in the Arkansas Valley and at site

118 in the Ouachita Mountains. The causes of these

decreases and increases in concentration are unknown.

Although the sites were not considered to be substantially affected by STP’s, some sites are downstream

from STP’s that might be affecting concentrations

enough to contribute to these changes in water quality.

Some sites (2, 7, and 101) are in agricultural basins and

not downstream from any STP’s.

Phosphorus. The Aquatic Team concluded that

concentrations of total phosphorus have not changed

substantially at most sites (fig. 2.12). Increases in total

phosphorus concentrations have occurred at about onehalf of the sites in the Springfield Plateau (sites 64, 66,

69, 71, 72; and site 60) since about 1980. All of the

Springfield Plateau sites with increasing concentrations

are “pasture” or “forest-pasture mix” sites. Decreases

in total phosphorus concentrations have occurred at

about one-third of the sites in the Salem Plateau (sites

10, 11, and 12); most of these sites with are Salem

Plateau “forest” sites. The Geological Survey laboratory

bias in the early 1980’s may at least partially explain

these decreases. These Salem Plateau sites also are

downstream from STP’s, although the STP’s are not

considered to be substantially affecting the water quality

at these sampling sites.

Concentrations of orthophosphate have not changed

substantially at most sites (fig. 2.13). The relatively few

number of sites and limited orthophosphate data make

any determination of spatial or land-use patterns affecting water-quality trends difficult. The team concluded

that, although data are limited, concentrations might

have decreased at some sites in the Osage Plains in the

time for which data are available (sites 2, 56, and 57).

Suspended sediment and suspended solids.

Little data concerning suspended sediment concentrations were available. Concentrations have not changed

substantially at sites for which data were available.

Similarly, concentrations of suspended solids have

not changed substantially at most sites (fig. 2.14).

However, decreases have occurred at the two sites

representative of the Osage Plains (sites 1 and 81).

Decreases in concentrations also have occurred at

several sites in the Salem Plateau (sites 50, 51, 53, 55,

and possibly others) and Arkansas Valley (site 105).

The decreasing concentrations may be the result of

some change in agricultural practices that has decreased the amount of soil and other suspended particles transported into streams.

Implications and Opportunities

On the whole, the Ozark-Ouachita Highlands are

blessed with clean water. Moreover, the analysis of

trends indicates that these conditions are substantially

unchanged since the 1970’s. However, it is also evident

that sewage treatment plants and more intensive land

uses have a greater effect on stream chemistry than

other land use activities. These more intensive land uses

can lead to impairment (adverse change) in streams.

(See Chapter 4 for a discussion of impaired waters.)

80
Figure 2.10—Concentrations of ammonia for water years 1970 through 1990 (Ozark Plateaus) and 1975

through 1995 (Arkansas Valley and Ouachita Mountains) at selected surface water sites.

1970 1975 1980 1985 1990

0

0.30

0

0.30

0

0.30

0

0.30

0

0.30

0

0.30

0

0.30

Site 1

Osage Plains cropland

Site 18

Boston Mountains forest

Site 53

Salem mix

Site 12

Salem forest

Site 72

Springfield mix

Site 63

Springfield mix

Site 41

Springfield forest

1975 1980 1985 1990 0

0

0

0

0

0.30

0.30

0.30

0.30

0.30

 

 

 

 

 

 

 

 

 Site 113

Ouachita Mountains mix

Site 111

Ouachita Mountains forest

Site 106

Arkansas Valley forest

Site 105

Arkansas Valley agriculture

Site 101

Arkansas Valley mix

1995

Arkansas Valley

and

Ouachita Mountains

Ozark Plateaus

Water year

Detected value

Censored value

Inferred concentration

 trend line

Milligrams per liter

Milligrams per liter

81
Figure 2.11—Concentrations of total ammonia plus organic nitrogen for water years 1970 through 1990 (Ozark

Plateaus) and 1975 through 1995 (Arkansas Valley and Ouachita Mountains) at selected surface water sites.

1970

1975

1975

1980

1980

1985

1985

1990

1990

0

0

0

0

0

0

0

0

0

0

0

1.5

1.5

1.5

1.5

1.5

1.5

1.5

1.5

1.5

1.5

1.5

Site 1

Osage Plains cropland

Site 18

Boston Mountains forest

Site 11

Salem mix

Site 72

Springfield mix

Site 63

Springfield mix

Site 41

Springfield forest

Site 118

Ouachita Mountains mix

Site 125

Ouachita Mountains forest

Site 105

Arkansas Valley agriculture

Site 101

Arkansas Valley mix

Site 97

Arkansas Valley forest

1995

Ozark Plateaus

Water year

Arkansas Valley

and

Ouachita Mountains

Detected value

Censored value

Inferred concentration

 trend line

Milligrams per liter

Milligrams per liter

82
Figure 2.12—Concentrations of total phosphorus for water years 1970 through 1990 (Ozark Plateaus) and 1975

through 1995 (Arkansas Valley and Ouachita Mountains) at selected surface water sites.

0

0.30

0

0.30

0

0.30

0

0.30

0

0.30

0

0.30

0

Site 41

Springfield forest

Site 63

Springfield mix

Site 72

Springfield mix

Site 12

Salem forest

Site 53

Salem mix

Site 18

Boston Mountains forest

Site 1

Osage Plains cropland

1970 1975 1980 1985 1990

1975 1980 1985 1990

0

0

0

0

0

0.30

0.30

0.30

0.30

0.30 

 

 

 

 

 

 

 

 

 

Site 113

Ouachita Mountains mix

Site 111

Ouachita Mountains forest

Site 106

Arkansas Valley forest

Site 105

Arkansas Valley agriculture

Site 101

Arkansas Valley mix

1995

Arkansas Valley

and

Ouachita Mountains

Ozark Plateaus

Water year

Detected value

Censored value

Inferred concentration

 trend line

Milligrams per liter

Milligrams per liter

83
Forest lands serve as the source of the cleanest

waters within the Assessment area. In order to ensure

that they continue to do so, managers will need to

actively implement best management practices (BMP’s)

to prevent decreases in water quality. Opportunities

exist for Federal agencies to continue to work closely

with State and local agencies and private landowners to

protect and promote water quality.

Figure 2.13—Concentrations of orthophosphate for water years 1970 through 1990 (Ozark Plateaus) and 1975 through

1995 (Arkansas Valley and Ouachita Mountains) at selected surface water sites.

1970 1975 1980 1985 1990

0

0.20

0

0.20

0

0

0.20

0.20

Site 18

Boston Mountains forest

Site 11

Salem forest

Site 53

Salem mix

Site 41

Springfield forest

1975 1980 1985 1990

0

0

0.20

0.20

 

Site 125

Ouachita Mountains forest

Site 87

Arkansas Valley forest

1995

Ozark Plateaus

Arkansas Valley

and

Ouachita Mountains

Water year

Detected value

Censored value

Inferred concentration

 trend line

Milligrams per liter

Milligrams per liter

84
Figure 2.14—Concentrations of suspended solids for water years 1970 through 1990 (Ozark Plateaus) and 1975

through 1995 (Arkansas Valley and Ouachita Mountains) at selected surface water sites.

Site 63

Springfield mix

Site 72

Springfield mix

Site 12

Salem forest

Site 53

Salem mix

Site 18

Boston Mountains forest

Site 1

Osage Plains cropland

100

100

100

100

100

100

0

0

0

0

0

0

1970 1975 1980 1985 1990

100

100

100

100

100

0

0

0

0

0

Site 113

Ouachita Mountains mix

Site 111

Ouachita Mountains forest

Site 106

Arkansas Valley forest

Site 105

Arkansas Valley agriculture

Site 101

Arkansas Valley mix

1975 1980 1985 1990 1995

Arkansas Valley

and

Ouachita Mountains

Ozark Plateaus

Water year

Detected value

Censored value

Inferred concentration

 trend line

Milligrams per liter

Milligrams per liter

85
Surface Water Quality (Lakes)

Question 2.2: What is the status of the surface

water quality of lakes within the Assessment

area?

As is true of surface water quality data concerning

streams, a great quantity of data is also available to

assess the water quality of lakes within the Assessment

area. To get as much useful information as possible in

the time allotted, the Aquatic Team investigated studies

where a sizable number of lakes in the Assessment area

were sampled by the States of Arkansas, Missouri, or

Oklahoma under the requirements of the Clean Water

Act (AR DPCE 1996, MO DNR 1994, OK DEQ 1996).

As part of the section 305(b) reporting process, the

Clean Water Act (CWA) requires that each State

submit a biennial assessment of the water quality of its

lakes—including their trophic status. Trophic status is

defined as the degree of eutrophication (see the following explanations) of a lake and provides insight into the

lake’s productivity and its future. In natural lakes, a

correlation exists between the age of a lake and its

trophic status. Reservoirs, because of their generally

higher inflow and outflow rates, do not function in the

same manner as natural lakes, but determining their

trophic status does assist in understanding water quality

problems affecting them (OK DEQ 1996).

Eutrophication is a cumulative process by which

lakes receive (1) agricultural runoff (nutrients such as

nitrogen and phosphorus), (2) rural and urban sewage

and industrial effluents, and (3) natural nutrients (such

as leaves and fallen trees). All these constituents

support increased algal and other aquatic plant growth

and gradually fill lakes with sediment and decaying

organic matter. Trophic status describes how far a

particular lake has advanced in the eutrophication

process and includes the following classifications:

• Oligotrophic: lakes that receive low levels of nitrogen,

phosphorus, and other nutrients and thus have little

algae or other aquatic plant growth;

• Mesotrophic: lakes that have received somewhat

more nutrients and have greater aquatic plant growth.

• Eutrophic lakes that have accumulated high levels of

nitrogen, phosphorus, and other nutrients and thus are

often very green due to large algal blooms.

• Hypereutrophic: lakes (the most advanced stage of

eutrophication) that have received exceptionally large

amounts of nitrogen, phosphorus, and other nutrients

and consequently have very heavy growths of algae

and other aquatic plants.

Trophic status is not necessarily a measure of lake

use. People who use lakes for sightseeing, picnicking,

swimming, or water skiing prefer oligotrophic lakes with

good water clarity. Anglers prefer slightly more

eutrophic lakes because they tend to have more species

and larger fish due to enhanced aquatic plant communities (MO DNR 1994). The team selected trophic status

as a suitable indicator of overall lake water quality.

Key Findings

 1. Within the Assessment area in Arkansas, 35

percent of the 48 lakes were classified as mesotrophic, 63 percent eutrophic, and 2 percent

(1 lake) as hypereutrophic.

 2. Within the Assessment area in Missouri, 13 percent

of the lakes were classified as oligotrophic, 32

percent as mesotrophic, and 55 percent as

eutrophic.

 3. Of the 30 Oklahoma lakes within the Assessment

area, 3 percent were classified as oligotrophic, 30

percent mesotrophic, 43 percent eutrophic, 17

percent hypereutrophic, and 7 percent (2 lakes) as

silt dominated.

Data Sources and Methods of Analysis

The Aquatic Team requested and received water

chemistry data for the major Federal reservoirs in the

Assessment area from the Arkansas, Missouri, and

Oklahoma offices of the Geological Survey. Originally,

the Aquatic Team selected a small list of four to six

water-chemistry parameters for each water body. To

minimize sampling bias, samples were taken around the

first of each year near the surface of each lake close to

the dam. The Aquatic Team intended to analyze these

data in order to establish trends, but found that for

meaningful analysis, they did not have data from similar

testing methodologies (e.g., testing dates, methods, and

86
sites) for enough reservoirs. This approach was therefore abandoned in favor of investigating data from the

Arkansas, Missouri, and Oklahoma 305(b) reports

previously noted.

Patterns and Trends

In 1989 and 1994, the Arkansas Department of

Pollution Control and Ecology (AR DPCE 1996)

sampled lakes across the State to determine their

trophic status as part of the required 305(b) report

analysis. To provide a relative ranking index, the Arkansas Department of Pollution Control and Ecology used

the following: (1) total phosphorus values converted to

micrograms per liter (μg/L) added to (2) chlorophyll-A

values in μg/L (chlorophyll-A is a measure of algal

standing crop and primary productivity) divided by

(3) secchi depth in inches (secchi depth is a visibility

measurement underwater at which equal black and

white quarters of a disk cannot be distinguished from

each other by the human eye). The Arkansas Department of Pollution Control and Ecology collected data for

this index from most of the Arkansas lakes between

mid-July and the end of August. Table 2.6 shows the

lakes selected, location, size, trophic status, total phosphorus, chlorophyll-A, secchi depth, Carlson Trophic

State Index, and type. Lake types include size, average

depth, and ecoregion. Note on table 2.6 that lakes within

the Assessment area generally fall into “A,” “B,” and

“E.” Type “C” and “E” lakes in the section 305(b)

report are all Arkansas Valley lakes. These lake “types”

are as follows:

• Type A—larger lakes, usually several thousand

acres in size, with average depths from 30 to 60 feet

(ft). These deep lakes are located in the Ozark

Plateaus, Ouachita Mountains, or Boston Mountains

and have land cover dominated by forests.

• Type B—smaller lakes, around 500 acres (ac) or

less in size, with average depths ranging from 10 to

25 ft. Most of these lakes—probably the most

heterogeneous group—are in the Ozark Plateaus,

Ouachita Mountains, and Boston Mountains; however, several are in the more mountainous areas of

the Arkansas Valley. Their watersheds are normally

dominated by forestlands.

• Type C—smaller lakes, generally ranging from 300

to 1,000 ac, with average depths normally less than

10 ft. These lakes are in the lowland or flatter terrain

areas of the Arkansas Valley and West Gulf Coastal

Plain physiographic areas. Watersheds of these lakes

include timberlands of both lowland hardwoods and

pines; some watersheds are broken by pasture lands

and small farms.

• Type D—generally 200 to 500 ac in size with

average depths of around 5 ft, including small impoundments in the delta area of the State plus two

similar type lakes from the large river alluvium

(sediment) of the West Gulf Coastal Plain.

• Type E—ranging from several thousand to over

30,000 ac in size with average depths usually less

than 10 ft, these are large lowland lakes of the West

Gulf Coastal Plain and the large alluvial areas of the

Arkansas Valley.

Arkansas ranks its lakes using the above system and

does not determine trophic status. However, by using

the chlorophyll-A and total phosphorus data for lakes

and reservoirs (table 2.6), the team assigned a trophic

status to them using Missouri’s classification scheme

(MO DNR 1994). The Carlson Trophic State Index is a

commonly used formula to derive trophic status: 9.8

natural log [chlorophyll-A] + 30.6. Based on the index,

the team classified each lake with a trophic status (see

table 2.7). Where the chlorophyll-A and total phosphorus values were in different trophic classification levels,

the total phosphorus value was used as the deciding

factor for classifying the particular Arkansas lake. In at

least half of the occurrences where chlorophyll-A and

total phosphorus values for an individual lake gave

differing trophic levels, the phosphorus value gave a

trophic status of eutrophic and the chlorophyll-A value

gave an oligotrophic status. In these situations, the likely

explanation is that something is limiting plankton production, such as turbidity from suspended solids (OK DEQ

1996).

When the Aquatic Team assigned a trophic status to

the 48 Arkansas lakes in the data base, 35 percent

were classified as mesotrophic, 63 percent eutrophic,

and 2 percent (1 lake) as hypereutrophic. Most of the

mesotrophic lakes were borderline eutrophic, and at

least half of the eutrophic lakes were borderline mesotrophic. Most of the large Federal reservoirs, with

87
Table 2.6—Surface area and trophic status of selected Arkansas lakes in the aquatic study area

Trophic Lake

Lake County Size status TP CHL-A Secchi Indexa typeb

 Acres - - - - μg/L - - - - In.

Atkins Pope 750 E 87 12.82 39 2.57 C

Bailey Conway 124 E 87 13.62 40 2.52 C

Barnett White 245 M 30 0.33 62 0.25 B

Beaver Benton 28,200 E 48 0.8 107 0.46 A

Beaverford Faulkner 900 E 77 3.2 81 1.27 B

Blue Mt. Logan 2,900 E 77 3.2 17.5 4.57 E

Bobb Kidd Washington 200 E 55 6.45 46 1.34 B

Brewer Conway 1,165 E 77 0.53 90 0.86 B

Bull Shoals Marion 45,440 M 30 1.34 146 0.11 A

Catherine Hot Spring 1,940 E 56 3 42 1.4 A

Charles Lawrence 562 E 69 25.63 19 4.99 B

Columbia Columbia 2,950 E 78 1.34 44 1.8 E

Conway Faulkner 6,700 E 76 26.7 15.8 6.52 E

Cove Logan 160 M 30 2.94 68 0.26 B

Cox Creek Grant 300 E 76 1.42 31 2.5 C

Crystal Benton 60 E 45 5.07 74 0.68 B

Degray Clark 13,200 E 158 3.2 74 2.18 A

Dequeen Sevier 1,680 M 30 9.5 59 0.42 A

Dierks Howard 1,360 E 50 15 47 0.64 A

Elmdale Washington 180 E 45 1.46 66 0.7 B

Fayetteville Washington 196 E 86 8.81 53 1.8 B

Ft. Smith Crawford 416 M 30 1.34 112 0.15 B

Gillham Howard 1,370 M 30 14 55 0.74 A

Greers Ferry Cleburne 31,500 E 59 1.07 245 0.25 A

Greeson Pike 7,200 E 48 0.01 74 0.65 A

Hamilton Garland 7,300 M 30 2.13 54 0.97 A

Harris Brake Perry 1,300 E 35 2.7 37 1.02 C

Hinkle Scott 965 E 47 1.34 81 0.6 B

Horsehead Johnson 100 M 30 2.8 89 0.2 B

Hurricane Saline 300 M 30 10.3 31 0.82 C

Lee Creek Crawford 634 M 30 1.07 72 0.22 B

Maumelle Pulaski 8,900 E 35 2.1 35 1.06 A

Millwood Little River 29,500 E 51 8.4 27.3 2.19 E

Nimrod Yell 3,600 E 49 7.2 37 1.52 E

Norfork Baxter 22,000 M 30 1.87 142 0.12 A

Ouachita Garland 40,100 E 47 0.27 183 0.26 A

Overcup Conway 1,025 E 87 14.14 31 3.27 C

Pine Bluff Jefferson 500 H 138 26 25.5 6.43 D

Sequoyah Washington 500 E 55 7.38 35 1.79 B

Shepherd Springs Crawford 552 M 30 1.34 112 0.15 B

Shores Franklin 82 M 30 2.4 77 0.23 B

Spring Yell 82 M 30 2.14 72 0.24 B

Sugarloaf Sebastian 250 E 47 1.34 77 0.63 B

Swepco Benton 531 M 30 4.2 61 0.31 B

Wedington Washington 102 M 30 2.67 108 0.16 B

Wilhelmena Polk 200 E 77 0.1 37.5 2.06 B

Winona Saline 1,240 M 30 0.1 134 0.11 A

Wright Sebastian 350 E 67 6.87 44 1.68 B

μg/L = micrograms per liter; in. = inches; E = eutrophic; M = mesotrophic; TP = total phosphorus; CHL-A = chlorophyll-A;

Secchi = visibility measurement.

a The Carlson Trophic State Index; see text for description.

b AR DPCE lake types; see text for definitions.

Source: AR DPCE (1996).

88
high flow-through, fell into these borderline situations

while the smaller lakes fell into the higher value range

of the eutrophic category (due to low flow-through).

Lakes managed by the Arkansas Game and Fish

Commission fall within the eutrophic category due in

part to ongoing fertilization programs to improve fish

production and shade out rooted aquatic weeds by

increasing plankton production.

Missouri also classified trophic levels of its lakes

using the chlorophyll-A and total phosphorus ranges

presented in table 2.7. These values were derived from

trophic classifications for reservoirs in Midwestern

States. Table 2.8 presents the names, locations, trophic

status, total phosphorus, chlorophyll-A, and total nitrogen

of selected Missouri lakes. Research is ongoing in

Missouri to relate algal production in reservoirs to lake

retention times (period of time until the lake water

volume is replaced entirely by new water), turbidity,

nutrients, and fish production (MO DNR 1994). Trophic

status correlated strongly with the physiographic area of

the State. In the northern and western agricultural parts

of Missouri, most lakes with known trophic status were

eutrophic, while in the Highlands the trophic status was

equally divided between eutrophic and mesotrophic or

oligotrophic. All known hypereutrophic lakes were in

historically glaciated northern Missouri while all oligotrophic lakes were in unglaciated, highly weathered

Ozark terrain in southern Missouri (MO DNR 1994).

Within the Assessment area in Missouri, 13 percent

of the lakes were classified as oligotrophic; these mostly

Table 2.7—Trophic status as determined by chlorophyll-A,

total phosphorous, and the Carlson Trophic State Index

Carlson

Total Trophic State

Trophic class CHL-A phosphorus Indexa

 - - - - - - - μg/L - - - - - - -

Oligotrophic <3 <10 <40

Mesotrophic 3–10 10–30 40–50

Eutrophic 11–56 31–100 50–60

Hypereutrophic >56 >100 >60

μg/L = micrograms per liter; CHL-A = chlorophyll-A.

a The Carlson Trophic State Index; see text for description.

Source: MO DNR (1994), OK DEQ (1996).

occurred in the mountainous area of St. Francois

County. Thirty-two percent of the selected Missouri

lakes and reservoirs were classified as mesotrophic and

55 percent as eutrophic.

The two most important water quality parameters

sampled under the Oklahoma Conservation

Commission’s lake sampling program were turbidity and

chlorophyll-A (OK DEQ 1996). In some parts of the

United States, measures of water clarity like secchi

depth or turbidity will often correlate strongly with levels

of chlorophyll-A. Usually algae will be the main constituent reducing water clarity and will account for the

bulk of measured turbidity. When a strong correlation

exists between water transparency and algae, the

water-clarity parameter provides a convenient indirect

measure of the degree of each lake’s trophic status.

Based upon 5 years of monitoring data, the Oklahoma

Conservation Commission determined, that measurements of water clarity parameters, such as turbidity,

were not as highly reliable for evaluating the associated

levels of algae as that measured through chlorophyll-A

for conditions in Oklahoma lakes and reservoirs. For

low turbidity values (< 5 nephelometric turbidity units

(NTU’s)) and for high turbidity values (> 100 NTU’s),

the chlorophyll-A values were generally less than 10

parts per billion. Over most of the range of turbidity

values encountered in sampled Oklahoma lakes, a given

level of turbidity occurring on different lakes could

correspond to widely divergent levels of algae. Since

chlorophyll-A data were collected directly, they were

converted to Carlson Trophic State Index numbers;

trophic status was assigned using the relationship given

in table 2.7.

Of the 28 Oklahoma lakes within the aquatic study

area, 3 percent were classified as oligotrophic, 30

percent mesotrophic, 43 percent eutrophic, 17 percent

hypereutrophic, and 7 percent (2 lakes) as silt dominated

(table 2.9). Fort Gibson Reservoir was hypereutrophicsilt dominated, and Wister Reservoir was eutrophichypereutrophic. Oklahoma lakes were unusual with

respect to their colloidal clay content. Resuspension of

colloidal clays can produce very high levels of turbidity,

a condition found in many Oklahoma lakes. In addition,

most of Oklahoma’s larger lakes were characterized by

a large degree of horizontal mixing. Because of these

conditions, the Oklahoma Water Board is exploring

alternative ways to determine trophic status.

89
Table 2.8—Trophic status of selected Missouri lakes in the aquatic study area

Trophic

Lake County status CHL-A T N

 - - - - - - - - -μg/L - - - - - - - - -

Atkinson St. Clair E 83 40 1,047

Austin Texas M 18 — 501

Binder Cole E 50 12 719

Bull Shoals Taney M 18 7 359

Council Bluff Iron M 9 3 298

Creve Couer St. Louis E 148 53 1,090

Fourche Ripley O 10 2 255

Fredericktown City Madison E 67 33 801

Goose Creek St. Francois M 14 4 399

H.S. Truman Benton E 44 12 1,120

Harrisonville Cass E 42 16 830

Indian Hills Crawford E 27 11 562

Lake Capri St. Francois O 7 1 314

Lake Carmel St. Francois O 8 1 326

Lake Forest (Lake Ann) Ste. Genevieve E 39 18 654

Lake Killarney Iron E 70 32 692

Lake Marseilles St. Francois O 10 2 356

Lake Northwoods Gasconade M 24 6 462

Lake of the Ozarks (Lower) Miller E 26 12 578

Lake of the Ozarks (Mid) Camden E 44 16 618

Lake Taneycomo Taney M 24 4 815

Lake Tishomingo Jefferson M 19 6 488

Lake Turner Dent E 20 18 —

Lake Wapapello Wayne E 35 18 525

Lake Wauwanoka Jefferson M 14 3 935

Lake Ziske Dent E 25 175 —

Lamar Barton E 82 46 1,015

Little Prairie Phelps E 29 8 501

Loggers Dent M 9 4 230

Macs Dent E 24 24 630

Miller Carter M 18 6 494

Monsanto (St. Joe State Park) St. Francois O 10 2 374

Montrose Henry E 195 68 1,295

Noblett Douglas M 20 5 247

Norfork Ozark M 24 6 614

North Cass E 64 25 850

Pleasant Valley Gasconade E 31 26 882

Pomme de Terre Hickory E 25 14 523

Pomona Howell E 50 10 605

Raintree Cass E 55 23 991

Ripley County Ripley E 38 35 904

Roby Texas M 16 4 434

Shane Dent O 7 1 393

Shawnee Dent E 32 28 656

Sims Valley Texas E 28 12 484

Spring Fork Pettis E 134 46 1,186

Stockton Cedar M 14 — 391

Sunnen Washington M 11 2 264

Table Rock Stone M 13 6 408

Tebo (Westmoreland) Pettis M 18 4 592

Timberline St. Francois O 10 2 309

Wanda Lee Ste. Genevieve E 63 30 64

Winnebago Cass E 50 19 799

E = eutrophic; M = mesotrophic; O = oligotrophic; TP = total phosphorus; CHL-A = chlorophyll-A;

TN = total nitrogen; μg/L = micrograms per liter; — = data unavailable.

Source: MO DNR (1994).

TP

90
Table 2.9—Surface area and trophic status of selected

Oklahoma lakes in the aquatic study area

Surface Trophic

Lake County area status

Acres

Broken Bow McCurtain 14,200 M

Brown Pittsburg 319 SD

Carl Albert Latimer 183 M

Cedar (Mena) Le Flore 78 M

Church (Lloyd) Latimer 160 E

Clayton (Old) Pushmataha 66 M

Eucha Delaware 2,860 H

Fort Gibson Cherokee 14,900 H, SD

Greenleaf Muskogee 920 M

Hudson Mayes 10,900 E

Hugo Choctaw 13,250 E

John Wells Haskell 194 O

Kerr Le Flore 43,800 E

Grand Lake O’ the

Cherokees Mayes 46,500 E

Nanih Waiya Pushmataha 131 E

Ozzie Cobb Pushmataha 116 E

Pine Creek McCurtain 3,750 E

Raymond Gary Choctaw 263 E

Sardis Pushmataha 13,610 M

Spavinaw Mayes 1,584 E

Spiro (New) Le Flore 254 E

Spiro (Old) Le Flore 34 H

Stillwell Adair 188 M

Talihina Latimer 23 E

W.R. Holway Mayes 715 M

Wayne Wallace Latimer 94 M

Webbers Falls Muskogee 11,600 H

Wister Le Flore 7,333 E, H

E = eutrophic; M = mesotrophic; O = oligotrophic;

H = hypereutrophic; SD = silt dominated.

Source: OK DEQ (1996).

Only the 1996 Arkansas Water Quality Inventory

Report (AR DPCE 1996) contained a trend analysis

(comparing 1989 versus 1994 data). The Aquatic Team

noted no significant trends in these data, which consist

of only one or two measurements during the 6 years.

Within the Assessment area, Oklahoma had a slightly

higher percentage (78 percent) of Federal reservoirs

that were eutrophic or hypereutrophic compared to

Missouri at 44 percent and Arkansas at 75 percent. Had

the two main stem lock and dam reservoirs on the

Arkansas River in Arkansas (at Ozark and Dardanelle,

AR) been classified, then Oklahoma and Arkansas

would have had nearly the same percentage split

between eutrophic and mesotrophic reservoirs. All large

lakes and reservoirs in the Arkansas Valley drainage

were eutrophic or hypereutrophic. The reservoirs of all

other Assessment-area river basins were more evenly

split between eutrophic and mesotrophic.

Implications and Opportunities

Given the concerns discussed earlier in this section

about turbidity or secchi visibility and chlorophyll-A

measurements not being the most accurate measures to

determine aquatic productivity or trophic status, additional research is certainly appropriate. While the use of

a standardized formula to calculate trophic status for

lakes across the Nation might be quite useful for some

purposes, it is a very weak analytical tool at a more

localized level. The research being conducted on trophic

classification by Missouri and Oklahoma may provide

better monitoring tools for the Ozark-Ouachita Highlands. States in the Assessment area will continue to

strive for better ways of determining trophic status and

water quality of lakes.

 Ground Water Quality

Question 2.3: What are the status and apparent

trends of the quality of ground water in the

Highlands?

Dissolved, colloidal, and suspended constituents in

ground water define water quality with respect to the

various potential uses of the resource. The presence of

many dissolved constituents at low concentrations is

acceptable and even desirable for most uses. However,

concentrations above certain threshold levels (depending

upon the particular constituent and specific water use)

can impair water quality. Chemical constituents that

define water quality derive from (1) natural geochemical

processes occurring in the hydrologic cycle, (2) general

biological activity, and (3) human activities. The quality

of ground water varies widely from one location to

another, often on a local scale, and even from one

91
subsurface horizon to another at the same site. Indeed,

the very definitions of good water quality versus poor

water quality are subjective and vary at the regional and

even local scale. For example, administrators of water

use in some municipalities might consider chloride

concentrations of more than 1,000 mg/L or nitrate

concentrations of 7 mg/L as nitrogen as “acceptable.”

However, other administrators, whose aquifers yield

water with less than 20 mg/L chloride and less than 0.2

mg/L nitrate, might consider the former values unacceptable. Thus, analysis of data on the quality of ground

water must include regional and local hydrologic conditions, land uses, definitions, and human effects on water

chemistry and water use.

With the advent of industrial fixation of nitrogen for

fertilizers, the amount of global atmospheric nitrogen that

is converted each year to a form accessible for use by

living organisms on land has doubled during this century

(Smil 1997). The results of this historic environmental

change—coupled with increasing human population,

conversion of land to agricultural use, and greatly

increased reliance upon nitrogen- and phosphorousbearing fertilizers within the Ozark Plateaus and

Ouachita Provinces—has led to notable changes in

water quality in some parts of the Assessment area. This

section of Chapter 2 includes discussions of the distribution of inorganic substances and nutrients in ground

water and other influential factors related to these

resulting effects on the water quality in the Highlands.

Key Findings

 1. The Springfield Plateau aquifer, the Ozark aquifer,

and aquifers of the Ouachita Province generally

provide water of excellent quality, though substantial differences in basic water chemistry occur

among these three settings.

 2. Ground water from springs differed substantially in

quality from that from wells in the Ozark aquifer,

the Springfield Plateau aquifer, and the aquifers of

the Ouachita Province. Springs in the Springfield

Plateau and Ozark aquifers are more susceptible to

contamination from surface sources.

 3. Wide-ranging, inorganic concentrations observed in

aquifers in the Ouachita Province are indicative of

both the province’s diverse geochemical environments and, for some water quality measures, the

influential land uses that are present.

 4. Background concentrations of nutrients in the

Springfield Plateau and Ozark aquifers are low;

nutrient concentrations were below detection limits

in many samples collected from sites in heavily

forested areas.

 5. Nitrite plus nitrate was detected more often and in

greater concentrations than any of the other

nutrients. Concentrations were greater than

background concentrations in many samples from

the Springfield Plateau and Ozark aquifers and

were positively correlated to the percent of agricultural land use around each site. Values ranged from

less than 0.05 to 25 milligrams per liter (mg/L) as

nitrogen, with a median of 1.6 mg/L in samples

from the Springfield Plateau and Ozark aquifers.

 6. In the Springfield Plateau and Ozark aquifers,

median nitrite plus nitrate concentrations generally

were greater in samples from springs than in

samples from wells.

 7. Concentrations of nitrite, ammonia, and ammonia

plus organic nitrogen were affected by land use in

the Springfield Plateau and Ozark aquifers.

 8. Background concentrations of nutrients in ground

water of the Ouachita Province are low; nutrient

concentrations were below detection limits in many

ground water samples. Nitrite plus nitrate was

detected in samples of ground water from sites in

the Ouachita Province at concentrations ranging

from below detection limits to 4.7 mg/L as nitrogen,

with a median of 0.16 mg/L.

 9. The occurrence of nutrients in ground water in the

Ouachita Province did not show a statistically

significant correlation with the percentage of

agricultural land use or urban land use around each

site.

Data Sources and Methods of Analysis

The Geological Survey began full implementation of

the National Water-Quality Assessment (NAWQA)

program in 1991 to provide a nationally consistent

description of the water quality for a large part of the

Nation’s water resources. Results contained in this

report for the Ozark Plateaus are from a NAWQA

92
study of data collected from 1993 through 1995

(Adamski 1997a, b). The NAWQA program is

described in reports by Hirsch and others (1988), Leahy

and others (1990), and Freiwald (1991) and is found on

the following Web site: <http://wwwrvares.er.usgs.gov/

nawqa/nawqa_home.html>.

Previous investigations of the regional hydrogeology

and movement and quality of ground water in the Ozark

Plateaus were part of the Geological Survey’s central

Midwest analysis of the regional aquifer system

(RASA) (Imes and Emmett 1994, Baker and Leonard

1995). Feder (1979) investigated the geochemistry of

the ground water of Missouri. The hydrogeology and

water quality of northwestern Arkansas were investigated by Lamonds (1972), Steele and others (1986),

Steele and Adamski (1987), Leidy and Morris (1990),

and Adamski and others (1995).

The limited number of studies of ground water quality

in the Ouachita Province have been more localized in

scope and have not involved uniform sampling and

analysis methods to ensure comparability of results as

have the NAWQA studies. Marcher and others (1987)

and Bryant and others (1983) described regional hydrology pertaining to coal mining. Independent assessments

of local and regional ground water resources and

potential mining effects in the western Ouachita Mountains and Arkansas Valley have been conducted and

presented in a series of reports by Marcher and others

(1981; 1983a, b, c), Slack (1983), and Christenson

(1995). Bedinger and others (1979) investigated the

ground water hydrology of the Hot Springs, AR, area.

Ground water in the Arkansas Valley was studied by

Bedinger and others (1963) and Cordova (1963). Albin

(1965), Plebuch and Hines (1967), and Halberg and

others (1968) described ground water resources at a

local scale in the eastern Ouachita Mountains. Cavalier

and Lavy (1987) conducted sampling for the Forest

Service to monitor the quality of ground water across

the central area of the Ouachita Mountains.

In the Ozark Plateaus Province, 229 samples of

ground water were collected from 215 sites as part of

the Ozark Plateaus NAWQA study unit (Adamski

1997a). Samples were collected from 1993 through

1995 using a network of springs and wells that were

randomly selected within the Springfield Plateau and

Ozark aquifers. (The unconfined parts of the Ozark

aquifer coincide with the Salem Plateau (Adamski

1997b). Samples were analyzed for field-measured

parameters (temperature, specific conductance, pH, and

alkalinity), major ions, nutrients, dissolved organic

carbon, methylene blue active substances, tritium, and

88 pesticides including metabolites. Using descriptive

and statistical methods, the Aquatic Team analyzed

water quality data from 199 sites for inorganics and

nutrients from the NAWQA study.

In the Ouachita Province, data were available from

107 sites, which included 33 springs and 74 wells (fig.

2.15). These data were derived for this report from

Geological Survey and Forest Service data bases for

1970 to 1994. Many of these samples were collected

between 1977 and 1986, but comprehensive data were

not available for all sites. Temperature and specific

conductance data were available for 103 sites, pH for

107 sites, alkalinity for 45 sites, sulfate for 107 sites, and

dissolved solids for 53 sites. Ammonia and nitrite data

were available for 12 sites, nitrite plus nitrate for 45

sites, and orthophosphorous for 20 sites.

The Aquatic Team analyzed these data to identify

factors affecting the geochemistry of the aquifer. The

team used the non-parametric Kruskal-Wallis analysisof-variance test (Helsel and Hirsch 1992) to identify

statistically significant differences in the medians of

inorganics and nutrients between samples from different

physiographic areas and site types (springs and wells).

The difference is assumed to be significant if the probability (P value) is less than 5 percent (< 0.05) that the

observed difference occurs by chance. In other words, if

the differences in the median values between the two

groups are greater than would be expected by chance,

these data will be described as statistically significant.

Patterns

Following is a brief, general discussion of the inorganic constituents of the Springfield Plateau and Ozark

aquifers and the aquifers of the Ouachita Province.

Nutrients in the ground water of these areas are

discussed next. Pesticide use affecting ground water

quality is presented in detail in Chapter 4 of this report.

Inorganics. Water samples for inorganics were

collected from 59 springs and 49 domestic wells in the

Springfield Plateau aquifer from 1993 through 1995. The

water type throughout most of this aquifer is calcium or

93
Figure 2.15—Location of ground water sampling sites in the aquatic study area.

Kansas

Oklahoma

Missouri

Arkansas

Aquatic study area

Physiographic province

 boundary

Physiographic section

 boundary

Ground water sample sites

Wells

Springs

Ozark Plateaus

Province

Ouachita Province

calcium-magnesium bicarbonate. The first third of table

2.10 shows that water temperatures ranged from 12.2

to 25 °C and specific conductance ranged from 81 (at

12.5 °C) to 1,553 microsiemens per centimeter (μS/cm)

at 25 °C in the Springfield Plateau aquifer. Values of pH

varied from 5.2 (acidic) to 7.9 (slightly basic). Alkalinity

ranged from 16 to 297 mg/L as calcium carbonate

(CaCO3

), sulfate from 0.7 to 180 mg/L as SO4, and

concentrations of dissolved solids ranged from 55 to 872

mg/L.

Water from Springfield Plateau aquifer springs was

geochemically different from water from wells in the

Springfield Plateau aquifer. In general, median specific

conductance, pH, alkalinity, and dissolved solids as well

as concentrations of calcium and magnesium were

statistically greater in samples from wells than in samples

from springs in the Springfield Plateau aquifer. In

contrast, concentrations of dissolved oxygen, potassium,

chloride, and silica were statistically greater in spring

samples than in well samples. Locally high concentrations of other ions in ground water, including sodium,

chloride, and sulfate, probably result from the ground

water interacting with nearby Pennsylvanian-age shales.

As shown on the middle third of table 2.10, water

samples for inorganics were collected from 32 springs

and 60 domestic wells in the Ozark aquifer from 1993

94
Table 2.10—Ground water quality data for major aquifers in the Assessment area

Water Specific pH, Nitrate + Orthotemper- conduct- field Alka- Sulfate, Dissolved nitrate, phosSites ature ance test linity dissolved solids Ammonia Nitrite dissolved phate

°C μS/cm at mg/L as mg/L as mg/L - - - - - -mg/L as nitrogen - - - - - - mg/L

25 °C CaCO3 SO4 as P

Springfield Plateau aquifer

All sites

Mean 14.9 358 7.0 155 11.6 206 0.02 0.01 2.60 0.02

Median 14.8 345 7.0 159 4.1 193 0.02 0.01 2.0 0.01

Minimum 12.2 81 5.2 16 0.7 55 0.01 0.01 0.03 0.01

Maximum 25 1,553 7.9 297 180 872 0.15 0.08 25 0.16

Number of samples 107 102 108 108 107 107 107 108 108 107

Wells

Mean 15.8 391 7.0 171 17.8 225 0.02 0.01 2.17 0.01

Median 15.4 366 7.1 183 5.5 214 0.02 0.01 1.1 0.01

Minimum 12.5 81 5.2 16 0.7 55 0.01 0.01 0.03 0.01

Maximum 25 1,553 7.9 284 180 872 0.15 0.08 25 0.16

Number of samples 49 49 49 49 48 48 48 49 49 48

Springs

Mean 14.2 327 6.9 141 6.47 190 0.02 0.01 2.95 0.02

Median 14 327 7.0 134 4.0 178 0.01 0.01 2.6 0.02

Minimum 12.2 83 6.0 24 1.8 61 0.01 0.01 0.3 0.01

Maximum 18.8 570 7.6 297 33 382 0.06 0.02 8.3 0.13

Number of samples 58 53 59 59 59 59 59 59 59 59

Ozark aquifer

All sites

Mean 15.6 498 7.3 243 15.3 278 0.03 0.01 0.84 0.01

Median 15.3 468 7.3 237 7.65 259 0.02 0.01 0.21 0.01

Minimum 9.5 225 6.7 116 0.20 133 0.01 0.01 0.03 0.01

Maximum 24.2 1,825 8.2 478 190 1,220 0.36 0.18 5.2 0.03

Number of samples 92 87 92 87 90 90 91 91 91 91

Wells

Mean 16.4 529 7.3 241 19.5 299 0.04 0.01 0.78 0.01

Median 15.9 511 7.4 230 11 275 0.02 0.01 0.10 0.01

Minimum 9.5 225 6.8 116 0.20 133 0.01 0.01 0.03 0.01

Maximum 24.2 1,825 8.2 478 190 1,220 0.36 0.18 5.2 0.02

Number of samples 60 57 60 57 59 59 60 60 60 60

Springs

Mean 14.3 437 7.1 244 7.2 238 0.02 0.01 1.0 0.01

Median 14.2 453 7.0 248 5.5 250 0.02 0.01 0.5 0.01

Minimum 12.9 247 6.7 146 1.5 143 0.01 0.01 0.03 0.01

Maximum 16.9 637 7.7 365 36 332 0.04 0.01 4.2 0.03

Number of samples 32 30 32 30 31 31 31 31 31 31

Ouachita Province aquifers

All sites

Mean 21 754 6.8 155 90 404 0.09 0.01 0.43 0.03

Median 19.5 475 7.0 116 16 219 0.06 0.01 0.16 0.01

Minimum 6.9 23 3.2 1 0.05 15 0.02 0.01 0.01 0.0

Maximum 61.5 6,380 12.2 604 2,900 5,170 0.3 0.01 4.74 0.3

Number of samples 103 103 104 45 107 53 12 12 45 20

(continued)

95
Table 2.10—Ground water quality data for major aquifers in the Assessment area (continued)

Water Specific pH, Nitrate + Orthotemper- conduct- field Alka- Sulfate, Dissolved nitrate, phosSites ature ance test linity dissolved solids Ammonia Nitrite dissolved phate

°C μS/cm at mg/L as mg/L as mg/L - - - - - -mg/L as nitrogen - - - - - - mg/L

25 °C CaCO3 SO4 as P

Ouachita Province aquifers (continued)

Wells

Mean 20 971 7.0 191 116 497 0.13 0.01 0.27 0.03

Median 19.3 639 7.0 128 22.5 292 0.09 0.01 0.09 0.01

Minimum 6.9 56 3.2 1.0 0.05 42 0.02 0.01 0.01 0.0

Maximum 30 6,380 12.2 604 2,900 5,170 0.3 0.01 1.10 0.3

Number of samples 70 70 71 25 74 33 7 7 19 15

Springs

Mean 23 291 6.5 109 29 249 0.04 0.01 0.54 0.03

Median 19.8 171 6.7 65 10 161 0.04 0.01 0.20 0.01

Minimum 10 23 4.8 2.3 1.2 15 0.02 0.01 0.02 0.01

Maximum 61.5 2,010 8.0 360 450 1,290 0.08 0.01 4.74 0.12

Number of samples 33 33 33 20 33 20 5 5 26 5

°C = degrees Celsius; μS/cm = microsiemens per centimeter at 25 °C; mg/L = milligrams per liter; CaCO3 = calcium carbonate; P = phosphorus;

SO4 = sulfate.

through 1995. Water type throughout most of the Ozark

aquifer is calcium or calcium-magnesium bicarbonate.

Temperatures ranged from 9.5 to 24.2 °C, specific

conductance from 225 to 1,825 μS/cm, pH from 6.7 to

8.2, alkalinity from 116 to 478 mg/L as CaCO3

, sulfate

from 0.2 to 190 mg/L as SO4

, and concentrations of

dissolved solids ranged from 133 to 1,220 mg/L.

Water from Ozark aquifer springs was geochemically

different than water from wells in the Ozark aquifer. In

general, median temperature, pH, and sulfate concentrations were statistically greater in samples from wells

than in samples from springs in this aquifer.

As shown on the last third of table 2.10, data on

inorganic characteristics were available for 33 springs

and 74 wells sampled since 1970 in the Ouachita Province aquifers, and water temperatures ranged from 6.9 to

61.5 oC. Specific conductance ranged from 23 to 6,380

μS/cm, pH from 3.2 to 12.2, alkalinity from 1 to 604 mg/

L as CaCO3

, sulfate from 0.05 to 2,900 mg/L, and

concentrations of dissolved solids from 15 to 5,170 mg/L.

Nutrients. Data about ground water quality compiled for this study were analyzed for nitrite, nitrite plus

nitrate, ammonia, ammonia plus organic nitrogen,

phosphorus, and orthophosphate. Summary statistics of

selected nutrient data for the ground water samples

compiled during this study are listed in table 2.10.

Sufficient data for statistical comparisons between

aquifers of the Ozark Plateaus and Ouachita Provinces

only exist for nitrite plus nitrate. No data existed in the

Ouachita Province for ammonia plus organic nitrogen

and phosphorus.

Background concentrations of nutrients in ground

water of the Springfield Plateau and Ozark aquifers—

determined from concentrations in samples from

reference sites and forested areas—were below

detection limits in many samples (Adamski 1997a). In

samples collected from 25 heavily forested sites (where

the forest cover is greater than or equal to 90 percent of

the area within a 1-mile radius of the site), the 90thpercentile concentrations (assumed to represent maximum background concentrations) for nutrients were as

follows: ammonia, 0.02 mg/L; nitrite, less than 0.01

mg/L; nitrite plus nitrate, 0.98 mg/L; ammonia plus

organic nitrogen, less than 0.20 mg/L; phosphorus, 0.02

mg/L; and orthophosphate, 0.01 mg/L.

Background concentrations of nitrite plus nitrate in

ground water of Ouachita Province aquifers were

estimated at 0.4 mg/L as nitrogen, based on five

samples from heavily forested areas in the Ouachita

Province. Not enough data on other nutrient forms exist

in the Ouachita Province to determine background

concentrations.

96
Nitrite. Nitrite concentrations generally were low in

samples of ground water in the Springfield Plateau and

Ozark aquifers. About 80 percent of the nitrite concentrations in these aquifers were less than the detection

limit of 0.01 mg/L as nitrogen. The source of nitrite in

ground water of the Springfield Plateau and Ozark

aquifers appears to be related to land use. Results of

Kruskal-Wallis test indicated that the percentage of

agricultural land use was greater around sites where

nitrite was detected than around sites where nitrite was

not detected.

Nitrite concentrations in samples from the Springfield

Plateau and Ozark aquifers were inversely correlated

with dissolved oxygen, particularly for wells in the

Springfield Plateau aquifer. Dissolved oxygen in most

samples was high, ranging from less than 0.1 to 12

mg/L, with a median of 6.8 mg/L. Nitrite is unstable in

aerated water (Hem 1985); hence, most of the nitrite in

ground water of the Springfield Plateau and Ozark

aquifers probably oxidizes rapidly to nitrate.

Nitrite probably is more common and more stable in

deep parts of the Springfield Plateau and Ozark aquifers

than in shallow parts. Nitrite concentrations in samples

from three deep monitoring wells were greater than 0.1

mg/L, whereas nitrite concentrations in samples from all

but one of the shallow monitoring wells were less than

0.04 mg/L. In addition, nitrite was detected more often

in samples from wells than in samples from springs.

Data exist for only 12 nitrite analyses of the Ouachita

Province aquifers. None of the samples showed concentrations above the 0.10 mg/L detection limit.

Nitrite plus nitrate. Median nitrite plus nitrate

concentrations were statistically greater in Springfield

Plateau wells and springs than in wells and springs in

the Ozark and Ouachita Province aquifers (fig. 2.16).

Median nitrite plus nitrate concentrations were 2 mg/L

as nitrogen for the Springfield Plateau sites and 0.21 and

0.16 mg/L as nitrogen for all sites in the Ozark and

Ouachita Province aquifers, respectively.

In the Springfield Plateau and Ozark aquifers, nitrite

plus nitrate was detected in ground water samples more

often and in greater concentrations than any other form

of nitrogen. Because nitrite was below the detection

limit in most samples, nitrite plus nitrate in ground water

samples consisted primarily of nitrate.

Nitrite plus nitrate concentrations in the Springfield

Plateau and Ozark aquifers commonly exceeded

background levels. Nitrite plus nitrate concentrations

were greater than 0.98 mg/L as nitrogen in 57 percent

of the samples. Nitrite plus nitrate concentrations in

samples from four sites exceeded the maximum contaminant level (MCL) of 10 mg/L as nitrogen for nitrate

in drinking water. These results indicate that (1) elevated concentrations of nitrite plus nitrate in ground

water of the Springfield Plateau and Ozark aquifers are

widespread, particularly in areas where land use is

predominantly agricultural, and (2) ground water in both

aquifers is vulnerable to surface contamination. Susceptibility of the aquifers to such contamination stems from

Figure 2.16—Concentrations of nitrite plus nitrate concentrations in

wells and springs in the three major aquifers of the Assessment area.

100

10

1

0.1

0.01

WS WS WS

W

S

Well

Spring

Ozark

Aquifer

Springfield

Plateau

Ouachita

Province

(60) (31) (49) (59)

b

a

(19) (26)

b

P-value—probability that observed difference occurs by chance. Probabilities less than

5 percent (<0.05) are assumed to be significant.

Number in parentheses—number of analyses included in computation of percentiles.

(66)

p<0.05

90th percentile

75th percentile

50th percentile (median)

25th percentile

10th percentile

Within a compared group, distributions

associated with the same letter are

not significantly (p<0.05) different

a

DL Detection limit

a

a a

DL

Milligrams per liter

p<0.05

97
Agricultural or urban land uses did not appear to be

significant factors affecting nitrite plus nitrate concentrations in the Ouachita Province. Nitrite plus nitrate

concentrations in samples showed no correlation to the

percentages of agricultural or urban land uses around

each sampled site.

Median nitrite plus nitrate concentrations were

greater in samples collected from springs (0.2 mg/L)

compared to samples collected from wells (0.09 mg/L);

however, the difference is not statistically significant.

Land use around well and spring sites was not statistically different, either.

Ammonia. As with nitrite plus nitrate, ammonia

concentrations in most samples of ground water in the

Springfield Plateau and Ozark aquifers were low (table

2.10). Ammonia concentrations were less than the

detection limit of 0.01 mg/L as nitrogen in 22 percent of

the samples. Ammonia concentrations were less than or

equal to the background concentration of 0.02 mg/L as

nitrogen in 76 percent of the samples. Thirty samples

had ammonia concentrations greater than 0.03 mg/L.

As with nitrite and nitrite plus nitrate, the source of

ammonia in ground water samples in the Springfield

Plateau and Ozark aquifers probably was related to land

use, however, concentrations of ammonia in samples did

not statistically correlate with percent agricultural land

use around sites. Data exist for only 12 ammonia

analyses for the Ouachita Province aquifers. Only one

concentration was detected above the detection limit.

Ammonia plus organic nitrogen. As with nitrite

and ammonia, concentrations of ammonia plus organic

nitrogen in samples from Springfield Plateau and Ozark

aquifers were low. Ammonia plus organic nitrogen was

detected in less than 10 percent of the samples.

The ammonia plus organic nitrogen detected in the

samples in the Springfield Plateau and Ozark aquifers

consisted primarily of organic nitrogen. Organic nitrogen

ranged from 27 to 98 percent of the concentration, with

a median of 75 percent. The presence of organic

nitrogen in water indicates contamination by sewage or

other organic wastes (Hem 1985). Because most of

these samples were from sites near pastures and

livestock operations, the source of organic nitrogen in

the samples probably was animal wastes.

Like nitrite and ammonia, organic nitrogen is unstable

in water with high concentrations of dissolved oxygen

the region’s permeable soils and the fractures and

solution openings in the bedrock that allow rapid recharge of the ground water by percolation (the slow

passage of a liquid through a filtering medium).

Nitrite plus nitrate concentrations in ground water of

the Ozark Plateaus were negatively correlated with

percent forest cover within a 1-mi radius and positively

correlated with agriculture use. These correlations are

strong considering the complexities of the Ozark

Plateaus hydrogeology and the difficulty and potential

degree of error in determining the exact recharge areas

of springs and contributing areas to wells. These results

indicate that concentrations of nitrite plus nitrate in

ground water increase as percent of agricultural land

use around the site increases. The correlation was

stronger for samples from springs than for samples from

wells.

Median concentrations of nitrite plus nitrate were

statistically greater in samples collected from springs in

the Springfield Plateau aquifer than in samples collected

from springs in the Ozark and Ouachita Province

aquifers (fig. 2.16). These results probably are related

to the substantially greater agricultural land use overlying the Springfield Plateau aquifer compared to the

Ozark and Ouachita aquifers. Median agricultural land

use around spring sites in the Springfield Plateau aquifer

was 67 percent compared to 9 percent agricultural land

use around spring sites in the Ozark aquifer.

Median nitrite plus nitrate concentrations were not

statistically different between samples from wells and

samples from springs in the aquifers (fig. 2.16). Median

nitrite plus nitrate concentrations for samples from both

springs and wells in the Ozark aquifer were less than 1

mg/L, which is within background levels, because most

sites, particularly springs, have a large percent of forest

cover associated with them.

In the Ouachita Province, nitrite plus nitrate was

detected in ground water samples more often and in

greater concentrations than any other form of nitrogen.

Nitrite plus nitrate concentrations in the aquifers of the

Ouachita Province exceeded the background level of

0.4 mg/L in 13 of 45 samples (29 percent). Nitrite plus

nitrate did not commonly exceed 1 mg/L (5 of 45

samples, 11 percent). Nitrite plus nitrate concentrations

did not exceed the MCL of 10 mg/L as nitrogen for

nitrate in drinking water in any sample.

98
(Hem 1985) and is probably oxidized rapidly to nitrate.

Samples from springs and domestic wells, even sites

located in or near pastures, commonly had concentrations of nitrite, ammonia, and organic nitrogen less than

the detection limit. This result is consistent with the high

concentrations of dissolved oxygen common in samples

from Ozark Plateaus sites.

Phosphorus and orthophosphate. Concentrations

of phosphorus and orthophosphate (table 2.10) were low

in ground water samples collected in the Springfield

Plateau and Ozark aquifers. Phosphorus and orthophosphate were less than the detection limit of 0.01 mg/L as

phosphorus in 41 percent of the samples. Phosphorus

was greater than the background concentration of 0.02

mg/L in about 15 percent of the samples; orthophosphate was greater than the background concentration of

0.01 mg/L as phosphorus in 30 percent of the samples.

Twenty-one samples had phosphorus or orthophosphate

concentrations greater than or equal to 0.05 mg/L as

phosphorus.

Phosphorus concentrations in samples were measured as the sum of all phosphorus forms present,

including orthophosphate. The median of the differences

between phosphorus and orthophosphate concentrations

in samples in the Springfield Plateau and Ozark aquifers

was less than 0.01 mg/L as phosphorus. With few

exceptions, phosphorus in samples consisted primarily of

orthophosphate.

Median orthophosphate concentrations were statistically greater in samples from Springfield Plateau springs

(0.02 mg/L) than in samples from Ozark aquifer springs

(0.01 mg/L). As with nitrite plus nitrate, the differences

in orthophosphate concentrations between samples from

the two aquifers probably resulted from differences in

land use overlying the aquifers.

Median phosphorus and orthophosphate concentrations were statistically different between samples from

springs (0.02 mg/L) and samples from domestic wells

(less than 0.01 mg/L) in the Springfield Plateau aquifer.

The results, which correspond with the results of nitrite

plus nitrate analyses, indicate that water from springs

generally is more susceptible to surface contamination

than water from wells.

In the Ouachita Province aquifers, data exist for only

20 samples for orthophosphate; 2 concentrations were

detected above the detection limit. There was no

statistical difference between orthophosphate concentrations between aquifers in the Ozark Plateaus and

Ouachita Province.

The solubility of phosphorus is affected by pH and

concentrations of other ions in the water. Phosphorus

can form insoluble residues with calcium and with

aluminum and iron hydroxides. Phosphorus also can be

absorbed and/or adsorbed onto clay minerals such as

kaolinite (Brady 1984). Hence, most of the phosphorus

applied to pastures in the Assessment area could either

remain in the soil or be transported with particulates in

the water.

Implications and Opportunities

Ground water from springs differed substantially

from wells in the Springfield Plateau, the Ozark, and the

Ouachita Province aquifers. Differences observed may

be attributed to shallower and shorter average flow

paths for water discharging in springs, closer proximity

to recharge areas, and greater contact with the surface

environment. These data indicate that springs are more

susceptible to contamination from surface sources.

Wide-ranging, inorganic water quality values observed in

the Ouachita Province are indicative of the Province’s

diverse geochemical environments and, for some water

quality resources, influential land uses that are present.

Nutrient concentrations in ground water were related

to land use in the Springfield Plateau and Ozark aquifers. Median concentrations of nutrients were greater in

samples from the Springfield Plateau aquifer, where

agricultural land use predominates, than in samples from

the Ozark aquifer, where forested land cover predominates. Nitrite plus nitrate concentrations positively

correlated to percent agricultural land use around each

site. The presence of organic nitrogen in some samples

indicates contamination by organic wastes—likely from

manure.

In the Ouachita Province, nitrite plus nitrate was

detected in ground water at concentrations ranging from

below detection limits to 4.7 mg/L as nitrogen, with a

median of 0.16 mg/L. Background concentrations of

nutrients in ground water of the Ouachita Province were

low; nutrient concentrations were below detection limits

in many samples. Nutrient data from forested sites in the

Ouachita Province may be used to define background

99
concentrations of nitrite plus nitrate. The occurrence of

nutrients in the Ouachita Province did not show a

statistically valid correlation with percent agricultural

land use or urban land use around each sampled site.

The Springfield Plateau, Ozark, and Ouachita Province aquifers generally provide water of excellent

quality, though substantial differences exist in the basic

water chemistry of these settings. With minimal treatment, the water in these aquifers generally is usable for

demanding applications (e.g., municipal water supply

and agricultural use). However, quantities are very

limited in some areas, particularly in the Ouachita

Province. In addition, all the aquifers are locally affected by land uses such as mining, agriculture, and

urbanization.

Aquatic Animals and Their Habitats

This section addresses the biology of aquatic systems

and, to a lesser degree, the kinds and types of aquatic

and riparian habitats within the Assessment area. In

contrast to the preceding portions of this chapter, the

following discussion does not make use of physiographic

provinces. Instead, the Aquatic Team chose to use

ecological sections to provide a more ecologically

refined way to examine patterns across the watersheds

of the Assessment area (as explained in the “Data

Sources and Methods of Analysis” subsection).

Diversity of Fishes

Question 2.4: What are the status and

distribution of fishes within the Assessment

area?

The Ozark-Ouachita Highlands are part of a region—the Southern United States plus the Missouri

Ozarks—that harbors the richest freshwater fish fauna

on the North American continent (Warren and Burr

1994). The Highlands’ streams and rivers alone are

home to at least 190 native fish species, representing 51

percent of the native freshwater fishes of the entire

Mississippi River Basin, about 24 percent of those of the

Continental United States, and 18 percent of all native

freshwater fishes of North America (Burr and Mayden

1992, Warren and Burr 1994). Arkansas, Missouri, and

Oklahoma each have a higher diversity of fishes than

any other State of comparable size west of the Mississippi River (Warren and Burr 1994). A major portion of

that diversity is concentrated in the Assessment area

(Pflieger 1975, Cross and others 1986, Robison and

Buchanan 1988).

The fishes of the aquatic study area reside within a

much larger natural region that encompasses geographically disparate and large tributaries of the western

Mississippi Alluvial Basin (e.g., the Missouri, Arkansas,

and Red Rivers) and borders or encompasses all or part

of eight ecological sections (see “Data Sources and

Methods of Analysis”). Complex drainage histories

beginning prior to the Pleistocene Age set the stage for

the division, isolation, and mixing of fish faunas that in

large part account for the richness and distinctiveness of

the region’s fishes (Mayden 1985, 1987a, b; 1988a, b;

Cross and others 1986; Robison 1986). The Highlands

are drained by several major river basins emptying into

the Mississippi Alluvial Basin. These may be divided

into two major groups: easterly flowing tributaries

(primarily the Gasconade, Osage, Meramec, St. Francis,

Black, White, and Arkansas Rivers) and southerly

flowing tributaries (primarily the Kiamichi, Little, and

Ouachita Rivers).

The Forest Service’s national hierarchical framework for classifying and mapping aquatic ecological

units (Maxwell and others 1995) places the Assessment area in the Arctic-Atlantic subzone, Mississippi

region, Interior Highlands subregion. As major rivers

flow into or out of the Highlands, most breach or border

one or more major ecotones (transitional zones between ecological communities) that influence diversity

and composition of fishes (Pflieger 1971, 1975;

Matthews and Robison 1988). To the north and west,

the region is bounded by the Central Lowlands and to

the south and east, by the West Gulf Coastal Plain and

Mississippi Alluvial Plain, respectively. These factors—

numerous river systems with varied histories and

ecological settings—provide the backdrop for the

uniqueness and high diversity of fishes in the OzarkOuachita Highlands.

100
 Key Findings

 1. Twenty-four fish families are represented by native

species in the Assessment area, with five families

containing about 78 percent of the fish fauna of the

region; two families—the perches (Percidae) and

minnows (Cyprinidae)—comprise more than half of

the fish fauna.

 2. The fish faunas of the aquatic study area have been

classified into four distinct geographical regions

based on species composition as follows: the Ozark

Fish Faunal Region, Southern Ozark and Ouachita

Mountain Fish Faunal Region, Big River Fish Faunal

Region, and a Lowlands Fish Faunal Region—West

Gulf Coastal Plain-Mississippi Delta (Mississippi

Alluvial Basin).

 3. In the northeastern part of the Assessment area,

native fish species richness is concentrated in the

Upper St. Francis River, Upper Black River, and

Upper White River drainages; in the west, it is

concentrated in the drainages of the Neosho-Illinois

Rivers and western portions of the Arkansas River.

 4. Native fish species density varies across the

Assessment area, with the highest densities of fish

species associated with ecological-hydrologic units

that are generally small and species rich or small

and adjacent to species-rich units.

 5. Conservatively, at least 14 percent of the fish fauna

is endemic to the Assessment area (restricted to a

particular geographic area); endemic species are

distributed among five fish families, with highest

endemicity among darters and minnows. Endemic

fishes are concentrated in 2 ecological sections: the

Ozark Highlands (16 endemic fish species) and the

Ouachita Mountains (7 endemic fish species).

Data Sources and Methods of Analysis

To examine the distribution of fish species, each of

the 10 major basins within the Assessment area was

subdivided into hydrologic units (watersheds) according

to standard eight-digit hydrologic unit codes (HUC’s)

(fig. 1.2). The Aquatic Team further subdivided 32 of

these 50 watersheds to form 2 or 3 “ecological-hydrologic units” by digitally overlaying ecological sections

(slightly modified from Keys and others 1995).

From north to south on figure 2.17, the four ecological sections in the Assessment area are the Ozark

Highlands (OZ), Boston Mountains (BM), Arkansas

Valley (AV), and Ouachita Mountains (OM). Some

watersheds within the aquatic study area lie partially in

sections outside the Highlands (those italicized in the

following tabulation). The following tabulation shows

how the ecological sections used in this analysis and in

the remainder of this chapter are roughly equivalent to

all or portions of the various physiographic units used

earlier in this chapter and elsewhere in this report:

Ecological section Physiographic unit

Ozark Highlands Ozark Plateaus Province minus

Boston Mountains

Boston Mountains Boston Mountains section of

Ozark Plateaus Province

Arkansas Valley Arkansas Valley section of

Ouachita Province

Ouachita Mountains Ouachita Province minus

Arkansas Valley section

Mississippi Alluvial Basin Mississippi Alluvial Plain

section of Coastal Plains

Province

Middle Coastal Plains, West Gulf Coastal Plain section

Western of Coastal Plains Province

Cross Timbers and Prairie Small part of Osage Plains

section of Central Lowland

Province

Osage Plains Portion of Osage Plains section

of Central Lowland Province

The distribution of fishes within a particular ecologicalhydrologic unit was determined primarily from maps in

Pflieger (1971, 1975), Miller and Robison (1973), and

Robison and Buchanan (1988). The determination of a

species’ occurrence within a unit depended on the

temporal (time) coverage, quality, and scale of source

distribution maps. Distributions in both Pflieger (1975) and

Robison and Buchanan (1988) were presented as

drainage maps for each species with dots indicating the

occurrence of a fish species at that point within the

drainage. The drainage maps allowed the team to make

relatively unambiguous interpretations of fish distributions.

101
Figure 2.17—River basins, watersheds, and ecological sections of the aquatic study area (showing derivation of ecological-hydrologic units).

Miller and Robison (1973) also used drainage maps for

each species, but distributions were shaded rather than

indicated by discrete points of occurrence. Nevertheless,

the quality and scale of these maps along with textual

descriptions of distributions permitted an accurate

delineation of a species’ occurrence within an ecologicalhydrologic unit. Pflieger (1975) reported known collections of fishes in Missouri from about 1905 to 1969. Miller

and Robison (1973) are current through the early 1970’s

for Oklahoma. Robison and Buchanan (1988) covered all

known and verified collections of fishes in Arkansas

before 1987.

 Information from these primary sources was augmented with fish distributional information presented in

Lee and others (1980), Cross and others (1986), and

Page and Burr (1991). Scientific and common names of

fishes generally follow that of Mayden and others

(1992). Distributions of species described subsequent to

the previously cited works were obtained from Harris

(1986, Ozark chub); Mayden (1988a, cardinal shiner);

and Humphries and Cashner (1994, rocky shiner). The

undescribed darter, Percina species, documented by

Robison and Buchanan (1988) from the Ouachita River

drainage, is included here under the longnose darter.

Oklahoma

Arkansas

River Basin Missouri

Gasconade

River Basin

Meramec

River Basin

Upper Black

 

River Basin

Upper White

River Basin

Neosho-Illinois

i

River Basin

Arkansas 

Ouachita-Saline

River Basin

Kiamichi-Little

River Basin

Upper St. Francis

River Basin

Ecological section

Ozark Highlands (OZ)

Boston Mountains (BM)

Arkansas Valley (AV)

Ouachita Mountains (OM)

Watershed boundary (hydrologic unit)

River basin boundary

River Basin

Osage

102
During late stages of preparation of this chapter, Ceas

and Page (1997) described one new species (brook

darter) and elevated two subspecies to species status

(strawberry and current darters). These last three

species are included here under the orangethroat darter.

Fish species were noted as present or absent within

each ecological-hydrologic unit and classified as native,

endemic, or introduced. Fishes occurring in peripheral

(outside the Highlands) ecological-hydrologic units also

were noted. The status of a fish species reflects its

known historical presence within a unit but does not

necessarily indicate its continued present-day occurrence in a unit. Information to account for changes to

the fauna is inadequately synthesized for area-wide

analysis. Fishes were considered native if the Assessment area is within their known historical range and no

evidence of their having been artificially introduced is

available. Scientists define endemic fishes as those

species that have a restricted range within one locale.

Introduced fishes are defined as those that have been

intentionally or accidentally released in a locale. Some

species can be described as native, endemic, and

introduced. For example, Ozark bass initially were found

only in the Upper White River Basin drainage where

they are native and endemic. Ozark bass have also been

introduced to the Illinois watershed. Therefore, Ozark

bass occur in all three categories.

Diversity was analyzed using native fish species

richness, native fish species density, and number of

endemic species. Native fish species richness is the

number of native fish species within each ecologicalhydrologic unit. Ecological-hydrologic units vary in areal

extent, and fish species richness often increases with

increases in stream size or area drained. To examine the

effect of areal additivity (increases in area may be

accompanied by an increase in species), native species

richness was divided by the number of square miles

(multiplied by 100) to produce native fish species density

values for each unit. In addition, the log of native fish

species richness was regressed on the log area of

ecological-hydrologic units to examine the relationship

between species richness and unit size. Native fish

species richness, native fish species densities, and

regional endemicity were plotted on separate ecologicalhydrologic unit maps. Three levels of relative richness,

density, and endemicity were recognized among ecological-hydrologic units: primary, secondary, and tertiary.

Primary levels were assigned to the 15 to 17 units

(depending on tied scores) with the highest values;

secondary levels were assigned to the next highest 15 to

21 units; and tertiary levels, to the remaining units.

Hence, primary levels approximate values in the fourth

quartile or top 25 percent; secondary levels approximate

values in the third quartile or second 25 percent; and

tertiary levels approximate values in the first and second

quartiles or bottom 50 percent.

Fish faunal composition among drainages of the

region was taken from existing works for Arkansas

(Matthews and Robison 1988, Matthews and others

1992) and Missouri (Pflieger 1971). Although methods

of analysis varied among these authors, each relied on

comparing distributions of native fish species and

classifying the resulting similarity patterns into fish

faunal regions. The fish faunal regions recognized by

these authors are highly compatible and generally

congruent even along the shared Missouri-Arkansas

border. For Assessment purposes, the Aquatic Team

assumed that sections of drainages not included in these

previous works (e.g., units wholly in eastern Oklahoma)

are classified in the same fish faunal regions as adjacent

drainages in Arkansas.

Patterns and Trends

Fish faunal composition. Native fish diversity is

divided unevenly among families in the Assessment

area. Twenty-four fish families are represented by

native species within the region (table 2.11). Five

families contain about 78 percent of the fish fauna:

minnows (69 native species), perches (41), suckers (18),

sunfishes and basses (16), and bullhead catfishes (16).

Over 52 percent of the native fish fauna is comprised of

darters (perch family) and minnows. Some families

have fewer representatives, but the Assessment area

supports a significant number of North American

species in these families. For example, about 25 percent

of all topminnows (Fundulidae) and lampreys

(Petromyzontidae) from North America are recorded

from the Assessment area (Mayden and others 1992).

Analyses of fish faunal composition have been

independently undertaken for Arkansas (Matthews and

Robison 1988, Matthews and others 1992) and Missouri

(Pflieger 1971). The study by Matthews and Robison

(1988) used smaller drainage units than used here and

103
Table 2.11—Native, endemic, and introduced fishes of the aquatic study area

Family Species Common name Native Endemic Introduceda

Acipenseridae Acipenser fulvescens Lake sturgeon X

Acipenseridae Scaphirhynchus platorynchus Shovelnose sturgeon X

Amblyopsidae Amblyopsis rosae Ozark cavefish X X

Amblyopsidae Typhlichthys subterraneus Southern cavefish X

Amiidae Amia calva Bowfin X

Anguillidae Anguilla rostrata American eel X

Aphredoderidae Aphredoderus sayanus Pirate perch X

Atherinidae Labidesthes sicculus Brook silverside X

Atherinidae Menidia beryllina Inland silverside X

Catostomidae Carpiodes carpio River carpsucker X

Catostomidae Carpiodes cyprinus Quillback X

Catostomidae Carpiodes velifer Highfin carpsucker X

Catostomidae Catostomus commersoni White sucker X X

Catostomidae Cycleptus elongatus Blue sucker X

Catostomidae Erimyzon oblongus Creek chubsucker X

Catostomidae Erimyzon sucetta Lake chubsucker X

Catostomidae Hypentelium nigricans Northern hog sucker X X

Catostomidae Ictiobus bubalus Smallmouth buffalo X

Catostomidae Ictiobus cyprinellus Bigmouth buffalo X

Catostomidae Ictiobus niger Black buffalo X

Catostomidae Minytrema melanops Spotted sucker X

Catostomidae Moxostoma anisurum Silver redhorse X

Catostomidae Moxostoma carinatum River redhorse X

Catostomidae Moxostoma duquesnei Black redhorse X

Catostomidae Moxostoma erythrurum Golden redhorse X

Catostomidae Moxostoma macrolepidotum Shorthead redhorse X

Catostomidae Moxostoma poecilurum Blacktail redhorse X

Centrarchidae Ambloplites ariommus Shadow bass X

Centrarchidae Ambloplites constellatus Ozark bass X X X

Centrarchidae Ambloplites rupestris Rock bass X X

Centrarchidae Centrarchus macropterus Flier X

Centrarchidae Lepomis auritus Redbreast sunfish X

Centrarchidae Lepomis cyanellus Green sunfish X X

Centrarchidae Lepomis gibbosus Pumpkinseed X

Centrarchidae Lepomis gulosus Warmouth X

Centrarchidae Lepomis humilis Orangespotted sunfish X

Centrarchidae Lepomis macrochirus Bluegill X X

Centrarchidae Lepomis marginatusb Dollar sunfish X

Centrarchidae Lepomis megalotis Longear sunfish X X

Centrarchidae Lepomis microlophus Redear sunfish X X

Centrarchidae Lepomis miniatus Redspotted sunfish X

Centrarchidae Lepomis symmetricusb Bantam sunfish X

Centrarchidae Micropterus coosae Redeye bass X

Centrarchidae Micropterus dolomieu Smallmouth bass X X

Centrarchidae Micropterus punctulatus Spotted bass X

Centrarchidae Micropterus salmoides Largemouth bass X X

Centrarchidae Pomoxis annularis White crappie X X

Centrarchidae Pomoxis nigromaculatus Black crappie X

Clupeidae Alosa alabamae Alabama shad X

Clupeidae Alosa chrysochloris Skipjack herring X

Clupeidae Dorosoma cepedianum Gizzard shad X X

Clupeidae Dorosoma petenense Threadfin shad X X

Cottidae Cottus carolinae Banded sculpin X X

Cottidae Cottus hypselurus Ozark sculpin X X

Cyprinidae Campostoma anomalum Central stoneroller X X

Cyprinidae Campostoma oligolepis Largescale stoneroller X

Cyprinidae Carassius auratus Goldfish X

Cyprinidae Ctenopharyngodon idella Grass carp X

(continued)

104
Table 2.11—Native, endemic, and introduced fishes of the aquatic study area (continued)

Family Species Common name Native Endemic Introduceda

Cyprinidae Cyprinella camura Bluntface shiner X

Cyprinidae Cyprinella galactura Whitetail shiner X

Cyprinidae Cyprinella lutrensis Red shiner X

Cyprinidae Cyprinella spiloptera Spotfin shiner X

Cyprinidae Cyprinella venusta Blacktail shiner X

Cyprinidae Cyprinella whipplei Steelcolor shiner X

Cyprinidae Cyprinus carpio Common carp X

Cyprinidae Ericymba buccata Silverjaw minnow X

Cyprinidae Erimystax harryi Ozark chub X X

Cyprinidae Erimystax x-punctatus Gravel chub X

Cyprinidae Hybognathus argyritis Western silvery minnow X

Cyprinidae Hybognathus nuchalis Mississippi silvery minnow X

Cyprinidae Hybognathus placitus Plains minnow X

Cyprinidae Hypophthalmichthys molitrix Silver carp X

Cyprinidae Hypophthalmichthys nobilis Bighead carp X

Cyprinidae Luxilus cardinalis Cardinal shiner X

Cyprinidae Luxilus chrysocephalus Striped shiner X

Cyprinidae Luxilus pilsbryi Duskystripe shiner X X

Cyprinidae Luxilus zonatus Bleeding shiner X X

Cyprinidae Lythrurus fumeus Ribbon shiner X

Cyprinidae Lythrurus snelsoni Ouachita Mountain shiner X X

Cyprinidae Lythrurus umbratilis Redfin shiner X

Cyprinidae Macrhybopsis aestivalis Speckled chub X

Cyprinidae Macrhybopsis meekib Sicklefin chub X

Cyprinidae Macrhybopsis storeriana Silver chub X

Cyprinidae Nocomis asper Redspot chub X

Cyprinidae Nocomis biguttatus Hornyhead chub X

Cyprinidae Notemigonus crysoleucas Golden shiner X X

Cyprinidae Notropis amblops Bigeye chub X X

Cyprinidae Notropis amnis Pallid shiner X

Cyprinidae Notropis atherinoides Emerald shiner X

Cyprinidae Notropis atrocaudalis Blackspot shiner X

Cyprinidae Notropis bairdib Red river shiner X

Cyprinidae Notropis blennius River shiner X

Cyprinidae Notropis boops Bigeye shiner X

Cyprinidae Notropis buchanani Ghost shiner X

Cyprinidae Notropis chalybaeusb Ironcolor shiner X

Cyprinidae Notropis dorsalisb Bigmouth shiner X

Cyprinidae Notropis girardi Arkansas River shiner X

Cyprinidae Notropis greenei Wedgespot shiner X X

Cyprinidae Notropis heterolepis Blacknose shiner X

Cyprinidae Notropis hubbsib Bluehead shiner X

Cyprinidae Notropis maculatus Taillight shiner X

Cyprinidae Notropis nubilus Ozark minnow X X

Cyprinidae Notropis ortenburgeri Kiamichi shiner X X

Cyprinidae Notropis ozarcanus Ozark shiner X X

Cyprinidae Notropis perpallidus Peppered shiner X X

Cyprinidae Notropis potterib Chub shiner X

Cyprinidae Notropis rubellus Rosyface shiner X X

Cyprinidae Notropis sabinae Sabine shiner X

Cyprinidae Notropis shumardi Silverband shiner X

Cyprinidae Notropis stramineus Sand shiner X

Cyprinidae Notropis suttkusi Rocky shiner X X

Cyprinidae Notropis telescopus Telescope shiner X

Cyprinidae Notropis texanus Weed shiner X

Cyprinidae Notropis volucellus Mimic shiner X

Cyprinidae Opsopoeodus emiliae Pugnosed minnow X

(continued)

105
Table 2.11—Native, endemic, and introduced fishes of the aquatic study area (continued)

Family Species Common name Native Endemic Introduceda

Cyprinidae Phenacobius mirabilis Suckermouth minnow X

Cyprinidae Phoxinus erythrogaster Southern redbelly dace X

Cyprinidae Pimephales notatus Bluntnose minnow X X

Cyprinidae Pimephales promelas Fathead minnow X X

Cyprinidae Pimephales tenellus Slim minnow X

Cyprinidae Pimephales vigilax Bullhead minnow X

Cyprinidae Platygobio gracilisb Flathead chub X

Cyprinidae Semotilus atromaculatus Creek chub X X

Elassomatidae Elassoma zonatum Banded pygmy sunfish X

Esocidae Esox americanus Grass pickerel X

Esocidae Esox lucius Northern pike X

Esocidae Esox masquinongy Muskellunge X

Esocidae Esox niger Chain pickerel X

Fundulidae Fundulus blairae Western starhead topminnow X

Fundulidae Fundulus catenatus Northern studfish X X

Fundulidae Fundulus chrysotus Golden topminnow X

Fundulidae Fundulus dispar Northern starhead topminnow X

Fundulidae Fundulus notatus Blackstripe topminnow X

Fundulidae Fundulus olivaceus Blackspotted topminnow X

Fundulidae Fundulus sciadicus Plains topminnow X

Fundulidae Fundulus zebrinus Plains killifish X

Hiodontidae Hiodon alosoides Goldeye X

Hiodontidae Hiodon tergisus Mooneye X

Ictaluridae Ameiurus catus White catfish X

Ictaluridae Ameiurus melas Black bullhead X

Ictaluridae Ameiurus natalis Yellow bullhead X X

Ictaluridae Ameiurus nebulosus Brown bullhead X

Ictaluridae Ictalurus furcatus Blue catfish X

Ictaluridae Ictalurus punctatus Channel catfish X X

Ictaluridae Noturus albater Ozark madtom X X

Ictaluridae Noturus eleutherus Mountain madtom X

Ictaluridae Noturus exilis Slender madtom X X

Ictaluridae Noturus flavater Checkered madtom X X

Ictaluridae Noturus flavus Stonecat X

Ictaluridae Noturus gyrinus Tadpole madtom X

Ictaluridae Noturus lachneri Ouachita madtom X X

Ictaluridae Noturus miurus Brindled madtom X

Ictaluridae Noturus nocturnus Freckled madtom X

Ictaluridae Noturus placidus Neosho madtom X

Ictaluridae Noturus taylori Caddo madtom X X

Ictaluridae Pylodictis olivaris Flathead catfish X

Lepisosteidae Atractosteus spatula Alligator gar X

Lepisosteidae Lepisosteus oculatus Spotted gar X

Lepisosteidae Lepisosteus osseus Longnose gar X

Lepisosteidae Lepisosteus platostomus Shortnose gar X

Moronidae Morone chrysops White bass X

Moronidae Morone mississippiensis Yellow bass X

Moronidae Morone saxatilis Striped bass X

Mugilidae Mugil cephalus Striped mullet X

Percidae Ammocrypta clara Western sand darter X

Percidae Ammocrypta vivax Scaly sand darter X

Percidae Crystallaria asprella Crystal darter X

Percidae Etheostoma asprigene Mud darter X

Percidae Etheostoma blennioides Greenside darter X

Percidae Etheostoma caeruleum Rainbow darter X

Percidae Etheostoma chlorosomum Bluntnose darter X

Percidae Etheostoma collettei Creole darter X

Percidae Etheostoma cragini Arkansas darter X

(continued)

106
Table 2.11—Native, endemic, and introduced fishes of the aquatic study area (continued)

Family Species Common name Native Endemic Introduceda

Percidae Etheostoma euzonum Arkansas saddled darter X X

Percidae Etheostoma flabellare Fantail darter X X

Percidae Etheostoma fusiformeb Swamp darter X

Percidae Etheostoma gracile Slough darter X

Percidae Etheostoma histrio Harlequin darter X

Percidae Etheostoma juliae Yoke darter X X

Percidae Etheostoma microperca Least darter X

Percidae Etheostoma moorei Yellowcheek darter X X

Percidae Etheostoma nianguae Niangua darter X X

Percidae Etheostoma nigrum Johnny darter X

Percidae Etheostoma pallididorsum Paleback darter X X

Percidae Etheostoma parvipinneb Goldstripe darter X

Percidae Etheostoma proeliare Cypress darter X

Percidae Etheostoma punctulatum Stippled darter X X

Percidae Etheostoma radiosum Orangebelly darter X

Percidae Etheostoma spectabile Orangethroat darter X X

Percidae Etheostoma stigmaeum Speckled darter X

Percidae Etheostoma tetrazonum Missouri saddled darter X X

Percidae Etheostoma whipplei Redfin darter X

Percidae Etheostoma zonale Banded darter X

Percidae Percina caprodes Logperch X X

Percidae Percina copelandi Channel darter X

Percidae Percina cymatotaenia Bluestripe shiner X X

Percidae Percina evides Gilt darter X

Percidae Percina maculata Blackside darter X

Percidae Percina nasuta Longnose darter X X

Percidae Percina pantherina Leopard darter X X

Percidae Percina phoxocephala Slenderhead darter X

Percidae Percina sciera Dusky darter X

Percidae Percina shumardi River darter X

Percidae Percina uranidea Stargazing darter X

Percidae Percina vigil Saddleback darter X

Percidae Stizostedion canadense Sauger X

Percidae Stizostedion vitreum Walleye X X

Percopsidae Percopsis omiscomaycusb Trout-perch X

Petromyzontidae Ichthyomyzon castaneus Chestnut lamprey X

Petromyzontidae Ichthyomyzon fossor Northern brook lamprey X

Petromyzontidae Ichthyomyzon gagei Southern brook lamprey X

Petromyzontidae Lampetra aepyptera Least brook lamprey X

Petromyzontidae Lampetra appendix American brook lamprey X

Poeciliidae Gambusia affinis Western mosquitofish X X

Polyodontidae Polyodon spathula Paddlefish X

Salmonidae Oncorhynchus clarki Cutthroat trout X

Salmonidae Oncorhynchus mykiss Rainbow trout X

Salmonidae Salmo trutta Brown trout X

Salmonidae Salvelinus fontinalis Brook trout X

Salmonidae Salvelinus namaycush Lake trout X

Sciaendae Aplodinotus grunniens Freshwater drum X

a Species “native” to the Assessment area (as a whole) may be classified as “introduced” in certain watersheds where they did not occur naturally. b Denotes a fish species found within the aquatic study area but outside of the Ozark-Ouachita Highlands.

Source: Miller and Robison (1973), Pflieger (1975), Robison and Buchanan (1988).

107
provided an extensive and detailed analysis. These

studies also were limited to the political boundaries of

the respective States and varied in the level of classification achieved. A summary of their primary results is

presented here; for details, the reader is referred to the

original studies.

Analyses in Arkansas and Missouri identified a clear

split in fish distributions that separates lowland from

upland fishes. Most of the Assessment area is dominated by upland fish species; however, distinct groupings

of fishes exist within the uplands. Both studies identified

an Ozark Fish Faunal Region, consisting of fish assemblages in the Osage, Gasconade, Meramec, and Upper

St. Francis Rivers, much of the Upper White and Upper

Black Rivers, and the Neosho-Illinois drainages. The

Ozark Fish Faunal Region is the largest and most

distinctive such region in the Ozark-Ouachita Highlands

(Pflieger 1971, Matthews and Robison 1988).

Matthews and Robison (1988) also identified a

Southern Ozark and Ouachita Fish Faunal Region. It

includes several of the easternmost tributaries of the

Ozark uplift in Arkansas (e.g., the Eleven Point, Strawberry, and lowermost Spring Rivers and portions of the

Middle Fork White River), the White River below

Batesville, and the Little Red River. The Southern

Ozark and Ouachita Fish Faunal Region also includes

most of the tributaries of the Arkansas River that drain

the southern flanks of the Boston Mountains. Virtually

all the streams on the Ouachita Mountains also were

included, as the name implies (Matthews and Robison

1988). The drainages included in this faunal region

indicate that a strong similarity of fishes occurs among

drainages from southwestern to northeastern Arkansas.

Furthermore, although some of these rivers drain areas

that are geologically Ozarkian, the fishes of those rivers

have more affinity with fishes on the Ouachita uplift

than with more northern Ozark fishes. Mayden (1985)

suggested a continuous pre-glacial connection existed

between the Ozarks and Ouachitas before the area was

topographically split by headwater erosion of the

Arkansas River. This view is supported by present-day

similarities in upland fishes of the Ouachita Mountains

and southern Ozarks (Matthews and Robison 1988).

At least two other fish faunal regions were identified

by both Matthews and Robison (1988) and Pflieger

(1971) that either occur within or exert substantial

influence on fish composition in the Assessment area: a

Big River Fish Faunal Region and a Lowlands (West

Gulf Coastal Plain-Mississippi Delta) Fish Faunal Region.

Within the Ozark-Ouachita Highlands, the Big River Fish

Faunal Region is represented primarily by the Arkansas

River main stem. To the north, the big river fish fauna of

the Missouri River and Mississippi River main stems

exerts influence on the fish species composition of the

lower reaches of the Meramec, Gasconade, and Osage

Rivers. Likewise, lowland fishes influence composition of

faunas in drainages extending beyond the Assessment

area. This is particularly true for the lower reaches of

the Upper St. Francis, Upper Black, and Upper White

River drainages in the northeast and the Ouachita and

Kiamichi-Little River drainages in the south.

Native fish species richness and density. The

number of native fish species is not evenly distributed

among the ecological-hydrologic units (fig. 2.18), nor is

it oriented to a simple geographical axis or direction.

Species richness averaged 75 fish species per ecological-hydrologic unit and ranged from 22 to 114 species.

Most units, however, showed diverse fish faunas—57 of

the 61 units in the Highlands have more than 50 species.

Two separate geographical centers with primary

levels of fish species richness (89 to 114 species) are

apparent (fig. 2.18). One occurs near the western edge

and the other along the northeastern edge of the Assessment area. The western center is comprised of

units within the Neosho-Illinois drainage (Lake O’ the

Cherokees (OZ), Lower Neosho (OZ), and Illinois (OZ

and BM) units) and the Arkansas River drainage (DirtyGreenleaf (BM), Kerr Reservoir (AV), Kerr Reservoir

(BM), Dardanelle Reservoir (AV), and Poteau units).

The northeastern center is comprised of the Upper St.

Francis River Basin and units of the Upper Black River

Basin (Current (OZ), Upper Black (OZ), Spring (OZ),

and Strawberry (OZ)). The Lower Little River (OM)

and Upper Ouachita (OM) units along the southern

edge of the area also show primary levels of richness.

Units with secondary levels of fish species richness

(75 to 87 species) generally are located in the southern

two-thirds of the Assessment area, and those with tertiary

levels, in the northern one-third (fig. 2.18). Two exceptions are the Meramec unit (Meramec River drainage

(OZ)) and Lower Osage unit (Osage River drainage

(OZ)), which show secondary levels of richness. Aggregations of secondary-level richness occur in units of the

Upper White River drainage (e.g., Little Red (BM),

108
Figure 2.18—Levels of native fish species richness by ecological-hydrologic unit.

Middle White (BM), Middle White (OZ), Bull Shoals

(OZ) and Beaver Reservoir units (OZ)); Ouachita-Saline

drainage (Upper Saline (OM) and Ouachita Headwater

(OM) units); and Kiamichi-Little drainage (Mountain Fork

(OM) and Upper Little (OM) units). Most units in the

Gasconade and Osage River Basins show tertiary levels

of richness (less than 75 species).

Ecological-hydrologic units positioned as ecotones

tended to be associated with primary levels of richness.

The cluster of primary levels of richness observed in the

northeastern units reflects their ecotonal position

between the uplands of the eastern Ozarks and lowlands of the Mississippi Alluvial Basin. These drainages

are enriched by having representatives of both upland

and lowland fish species and by high numbers of

endemic fishes (Pflieger 1971, Cross and others 1986,

Matthews and Robison 1988). Likewise, the primary

richness levels observed along the western edge of the

Assessment area reflect a major shift from prairie to

upland complemented by the influence of the lowland

and big river fish fauna of the Arkansas Valley

(Matthews and Robison 1988). Fish diversity increases

generally from west to east across the Prairie Division,

which lies immediately west and northwest of the

Species richness

Primary

Secondary

Tertiary

Outside units

Oklahoma

Arkansas

Missouri

109
Assessment area, and reaches its highest levels in the

Assessment area (Pflieger 1971, Miller and Robison

1973, McAllister and others 1986). The aggregation of

units with tertiary levels of richness in the Gasconade

and Osage Rivers reflects the relatively sparse prairie

fish fauna of the Missouri River Basin as well as effects

of Pleistocene Age glaciation (Cross and others 1986).

The fish fauna in these units is not enriched to the

extent of other units that are positioned as ecotones.

The density of native fish species was highly variable

among ecological-hydrologic units ranging from 3 to 36

and averaging 10.5 native species per 100 square miles

(mi2

). The density of native species in a unit was

correlated negatively with unit area (r = -0.71, P <

0.0001). Regression of the log of native species richness

with the log of square miles in units also was statistically

significant (P < 0.0007). However, the relationship

accounted for only 18 percent of the variation in native

species richness (where log (species richness) = 1.29 +

0.193 log (unit area) and r2

 = 0.18).

Primary levels of fish species density (13 to 36 fish

species per 100 mi2

) were associated generally with

smaller units (fig. 2.19). Twelve of the 15 units with

primary levels of density were less than 600 mi2

 in area.

In contrast, 48 units with varying levels of density were

greater than 600 mi2

 in area. Ten of the units with

primary density levels also had primary or secondary

levels of species richness (fig. 2.18). For example, units

in the species-rich Neosho-Illinois drainage (Lake O’

the Cherokees (OZ), Lower Neosho (BM), and Illinois

(BM) units) showed primary levels of fish species

density as did units along the southern and eastern

edges (e.g., Lower Little (OM), Upper Ouachita (OM),

and Middle White (BM) units) of the Assessment area.

One unit in the relatively species-poor Osage River

drainage was an exception to these patterns—the South

Grand (OZ) unit showed primary levels of species

density but not primary or secondary levels of species

richness.

Secondary levels of species density (8 to 12 fish

species per 100 mi2

) (fig. 2.19) were associated with

units along the boundary of the Assessment area and

near the Arkansas and Missouri Rivers. Nine of 18 units

showing secondary levels of species density also had

primary or secondary levels of species richness. Six

units along the southern and eastern boundaries showed

secondary levels of species density: the Upper Little

(OM), Little Missouri (OM), Upper Saline (OM),

Middle White (OZ), Strawberry (OZ), and Spring (OZ)

units. Six of these also showed primary or secondary

levels of species richness. Secondary levels occurred

within four units in the Arkansas River drainage

(Cadron (AV), Dardanelle Reservoir (AV), FrogMulberry (BM), and Kerr Reservoir (AV) units); three

of these units coincided with primary or secondary

levels of richness. Finally, five units in the northern

drainages of the Assessment area showed secondary

levels of species density: the Harry S. Truman Reservoir (OZ) (Osage River drainage), Lower Osage River

(OZ), Bourbeuse (OZ) (Meramec River drainage),

Lower Gasconade (OZ), and Big Piney (OZ) units (both

Gasconade River drainages). None of these, with the

exception of the Lower Osage (OZ) unit, had primary

or secondary levels of species richness.

Small ecological-hydrologic units within the OzarkOuachita Highlands may show high native fish species

densities because these units are influenced by the fish

fauna of surrounding units (Sheldon 1987). Put simply,

the high densities in these units would be predicted to

decline if these units were isolated from surrounding

units. This hypothesis is supported by the strong negative correlation between density of native fishes and

area and by the weak relationship between number of

native species and area. Nevertheless, units with

primary or secondary levels of both native fish richness

and density may be considered exceptional areas of fish

diversity within the Assessment area.

Endemic fishes. Conservatively, at least 26 species

of fishes (14 percent of the fish fauna) are endemic to

the Assessment area. Ongoing studies indicate that

several currently recognized species are, in fact, two or

more distinct species. For example, Eisenhour (1996)

indicated that at least two distinct species now included

under the name speckled chub inhabit the Assessment

area. Likewise, the stippled darter consists of additional

distinct, but not yet formally described, species (Robison

and Buchanan 1988), as do the Ozark madtom (Grady

and LeGrande 1992) and longnose darter (Robison and

Buchanan 1988). Several other subspecies of fishes in

the area likely will be recognized as distinct endemic

species after further study (Cross and others 1986,

Robison and Buchanan 1988, Mayden and others 1992).

110
Endemic fishes within the Assessment area represent six fish families: the perch, minnow, catfish, sculpin,

cavefish, and sunfish (table 2.11). The perch (all

darters) and minnow families have the highest numbers

of endemic species with 10 and 9, respectively. Hence,

within these two largest families, 24 percent of all

darters and 16 percent of all minnows within the area

are endemic. In addition, the Assessment area harbors

at least four endemic madtom catfishes (Caddo, checkered, Ouachita, and Ozark madtoms), one endemic

sculpin (Ozark sculpin), one endemic cavefish (Ozark

cavefish), and one endemic sunfish (Ozark bass).

At least one endemic fish species is found in 57 of

the 61 ecological-hydrologic units in the Assessment

area (table 2.12). Endemicity averaged 4.6 endemic

species per unit and ranged from 0 to 13. Primary levels

of endemicity (7 to 13 endemic fishes) were aggregated

around the Upper White and Upper Black River

drainages (fig. 2.20). The number of endemic species

was highest in units of the Upper White River drainage

(9 to 13 endemic species), including Beaver Reservoir

(OZ and BM), James (OZ), Middle White (OZ and

BM), Bull Shoals (OZ), North Fork White (OZ), Little

Red (OZ), and Buffalo (OZ) units. The next highest the

Figure 2.19—Levels of native fish density by ecological-hydrologic unit.

Species density

Primary

Secondary

Tertiary

Outside units

Oklahoma

Arkansas

Missouri

111
Table 2.12—Native, endemic, and introduced fish species of the aquatic study area, by basin and

ecological-hydrologic unit

River basin Watershed code Native Endemic Introduced

Ecological-hydrologic unit name (HUC) Area species species species

 Mi2

Osage River Basin

Harry S. Truman Reservoir - OZ 10290105 497 59 2 1

Harry S. Truman Reservoir - OA 10290105 714 29 0 0

Sac - OZ 10290106 1,716 62 7 2

Sac - OA 10290106 255 18 0 0

Pomme de Terre - OZ 10290107 848 61 3 3

South Grand - OZ 10290108 89 22 0 1

South Grand - OA 10290108 1,959 37 0 2

Lake of the Ozarks - OZ 10290109 1,385 65 4 5

Niangua - OZ 10290110 1,031 67 7 5

Lower Osage - OZ 10290111 952 75 6 4

Lower Osage - OA 10290111 124 60 5 3

Gasconade River Basin

Upper Gasconade - OZ 10290201 1,788 61 6 3

Big Piney - OZ 10290202 756 61 6 4

Lower Gasconade - OZ 10290203 865 68 6 3

Lower Gasconade - OA 10290203 170 49 1 1

Meramec River Basin

Meramec - OZ 07140102 1,815 77 4 6

Meramec - OA 07140102 345 78 4 1

Bourbeuse - OZ 07140103 785 63 3 1

Bourbeuse - OA 07140103 52 44 1 1

Big - OZ 07140104 806 56 4 1

Big - OA 07140104 156 50 3 1

Upper St. Francis River Basin

Upper St. Francis - OZ 08020202 1,298 94 6 2

Neosho-Illinois River Basin

Lake O’ the Cherokees - OZ 11070206 586 90 3 2

Lake O’ the Cherokees - OA 11070206 334 74 1 1

Spring - OZ 11070207 1,793 87 2 4

Spring - OA 11070207 785 40 0 1

Elk - OZ 11070208 1,031 57 4 32

Lower Neosho - OZ 11070209 1,028 91 3 8

Lower Neosho - BM 11070209 238 86 2 5

Lower Neosho - OA 11070209 944 69 1 5

Illinois - OZ 11110103 1,329 97 4 8

Illinois - BM 11110103 321 99 2 6

Arkansas River Basin

Dirty-Greenleaf - BM 11110102 288 95 3 2

Dirty-Greenleaf - AV 11110102 229 77 1 1

Dirty-Greenleaf - OA 11110102 273 65 0 1

Robert S. Kerr Reservoir - BM 11110104 732 100 4 2

Robert S. Kerr Reservoir - AV 11110104 1,074 105 4 4

Poteau - OM 11110105 1,904 95 2 5

Frog-Mulberry - BM 11110201 719 56 3 2

Frog-Mulberry - AV 11110201 539 89 1 4

Dardanelle Reservoir - BM 11110202 668 39 3 2

Dardanelle Reservoir - AV 11110202 1,193 91 2 6

Lake Conway-Point Remove - AV 11110203 1,137 77 0 7

Petit Jean - AV 11110204 1,090 73 1 7

Cadron - AV 11110205 769 67 1 0

Fourche La Fave - OM 11110206 1,119 69 3 5

(continued)

112
Table 2.12—Native, endemic, and introduced fish species of the aquatic study area, by basin and

ecological-hydrologic unit (continued)

River basin Watershed code Native Endemic Introduced

Ecological-hydrologic unit name (HUC) Area species species species

 Mi2

Arkansas River Basin (continued)

Lower Arkansas-Maumelle - AV 11110207 280 68 0 5

Lower Arkansas-Maumelle - OM 11110207 197 29 0 1

Lower Arkansas-Maumelle - OA 11110207 630 72 0 6

Kiamichi-Little River Basin

Kiamichi - OM 11140105 1,316 68 2 1

Kiamichi - OA 11140105 506 84 1 1

Upper Little - OM 11140107 1,010 82 3 1

Upper Little - OA 11140107 399 100 3 3

Mountain Fork - OM 11140108 787 85 4 2

Mountain Fork - OA 11140108 69 94 3 1

Lower Little - OM 11140109 674 92 4 3

Lower Little - OA 11140109 1,301 114 4 7

Ouachita-Saline River Basin

Ouachita Headwaters - OM 08040101 1,546 75 6 9

Upper Ouachita - OM 08040102 673 89 4 9

Upper Ouachita - OA 08040102 1,089 105 2 4

Little Missouri - OM 08040103 613 68 4 8

Little Red - BM 11010014 1,320 83 8 6

Little Red - AV 11010014 411 54 3 2

Little Red - OA 11010014 90 18 0 1

Upper Black River Basin

Upper Black - OZ 11010007 1,439 101 5 3

Upper Black - OA 11010007 471 68 0 0

Current - OZ 11010008 2,453 105 9 5

Current - OA 11010008 172 64 3 0

Lower Black - OZ 11010009 490 72 5 2

Lower Black - OA 11010009 289 63 2 3

Spring - OZ 11010010 1,217 114 8 9

Eleven Point - OZ 11010011 1,202 71 7 2

Strawberry - OZ 11010012 789 89 4 4

HUC = hydrologic unit code; mi2

 = square mile; OZ = Ozark Highlands section; BM = Boston Mountains section;

AV = Arkansas Valley section; OM = Ouachita Mountains section; OA = Outside the Highlands Assessment area.

was in the drainage of the Upper Black River (7 to 9

endemic species), including the Current (OZ), Spring

(OZ), and Eleven Point (OZ) units. Together, these two

drainages are outstanding with regard to endemicity in

the Assessment area as well as within the entire

western Mississippi River Basin (Cross and others

1986). The Sac (OZ) and Niangua (OZ) units on the

Osage River also showed primary levels for endemicity

(seven endemic fishes each). Secondary levels of

endemicity (4 to 6 endemic fishes) include 21 units

scattered broadly across the Assessment area (fig.

2.20).

Few endemic fishes are widespread within the

Assessment area and most occur naturally only in

limited geographic areas or drainages. Two general

geographical distributions of endemic species may be

recognized: Ozark Highlands endemics and Ouachita

Mountains endemics. The wedgespot shiner, Kiamichi

shiner, and longnose darter are apparent exceptions to

this generalization, occurring in streams of both the

Ozark Highlands and Ouachita Mountains.

About 16 regionally endemic fish species occur only

in streams of the Ozark Highlands. Of these, six are

restricted to the Upper White and/or Upper Black River

113
Figure 2.20—Levels of endemic fish species richness by ecological-hydrologic unit.

Oklahoma

Arkansas

Missouri

Endemic species richness

Primary

Secondary

Tertiary

No endemics

Outside unit

Basins (i.e., duskystripe shiner, checkered madtom,

Ozark bass, yellowcheek darter, yoke darter, and

Arkansas saddled darter). The Ozark chub and Ozark

madtom are exclusively shared between these two

drainages and the Upper St. Francis; the Ozark minnow

is shared among the Upper White, Upper Black, Upper

St. Francis, and Illinois River drainages. The remaining

seven Ozark Highlands endemic fishes are found as

follows: (1) relatively widely distributed in the Ozark

Highlands (e.g., Ozark sculpin, bleeding shiner, stippled

darter), (2) only in the Ozark Highlands in Missouri and/

or in Meramec River tributaries (e.g., Niangua darter,

bluestripe darter, Missouri saddled darter), or (3)

extremely limited in distribution (e.g., Ozark cavefish

occur only in karst areas—areas dominated by limestone geology—of the Salem Plateau subsection of the

Ozark Highlands).

Seven regionally endemic fishes are essentially

restricted to streams of the Ouachita Mountains. Three

of these—the Ouachita Mountain shiner, rocky shiner,

and leopard darter—occur only in units of the KiamichiLittle drainage within the Assessment area. The Caddo

madtom, Ouachita madtom, and paleback darter have

very restricted ranges in Ouachita River tributaries of

114
the Ouachita-Saline drainage. The peppered shiner is

the only Ouachita Mountain endemic that occurs in both

the Kiamichi-Little and Ouachita-Saline drainages.

Implications and Opportunities

The Aquatic Team synthesized information on the

geographic patterns of fish distribution within the

Assessment area. The synthesis revealed that the

Ozark-Ouachita Highlands supports a large portion of

continental, national, and regional fish species diversity,

including a substantial number of endemic fish species.

The Aquatic Team was able to examine these rich fish

faunas on a relatively large and coarse scale only (i.e.,

presence or absence of fishes in ecological-hydrologic

units). The synthesis did not account for declines in fish

populations in recent times even though evidence is

available that some fish species have experienced a

reduction in range or fragmentation of populations within

the Assessment area (Robison and Buchanan 1988).

Many fishes in the Assessment area are found in

waters under Federal management (e.g., in national

forests). Given the trend toward continued human

population growth and accompanying modification of

aquatic habitats across the Assessment area, waters on

Federally managed lands are becoming increasingly

important for the continued existence of viable populations and communities of native fishes.

The effect of forest management practices on fishes

is an important, but little understood, component of land

management within the Assessment area. The response

of salmonid fishes to forest disturbance has been

examined extensively in the Pacific Northwest (e.g.,

Meehan 1991). As yet, no comparable body of literature

exists for fishes of the Assessment area, even though

the fishes of the Assessment area are the best known

members of the aquatic community (Pflieger 1971,

Cross and others 1986, Robison and Buchanan 1988).

The Aquatic Team considers the synthesis of data

about the distribution of fish to be a starting point for

identifying and prioritizing information needs that can

then be used to better conserve fish diversity.

Diversity of Mussels

Question 2.5: What are the status and distribution of unionacean bivalves (mussels, clams,

naiads, or unionids) within the Assessment area?

Unionacean bivalves (Mollusca: Bivalvia:

Pelecypoda: Unionaceae)—commonly referred to as

freshwater clams, mussels, naiads, or unionids—are

found worldwide. Their greatest diversity is in North

America, with about 297 recognized taxa (281 species

and 16 subspecies) (Williams and others 1993).

Seventy-five native freshwater mussel species and subspecies occur or have occurred in Arkansas (Gordon

and others 1980, Williams and others 1993, Posey and

others 1996); 65 mussel species are recognized from

Missouri (Oesch 1984, Williams and others 1993); and

55 freshwater mussel taxa have occurred historically

within Oklahoma (Branson 1973, 1982, 1983, 1984;

Williams and others 1993). There are now 73 native

freshwater mussel species in the Assessment area,

representing 26 percent of the native North American

mussel fauna.

The Assessment area encompasses 10 major river

basins that include the main stems of and tributaries to

the Missouri, Arkansas, Red, Ouachita, White, and St.

Francis River systems. Within the Assessment area,

these drainage systems traverse 24 ecological subsections of 4 ecological sections: (1) the Ozark Highlands,

(2) the Boston Mountains, (3) the Arkansas Valley, and

(4) the Ouachita Mountains.

Because freshwater mussels require a fish host to

complete the early stages of their life cycle, distributions

of fishes and mussels have coevolved. As discussed in

the previous section on fish diversity, complex drainage

histories beginning prior to the Pleistocene Age have

provided for division, isolation, and mixing of these two

aquatic faunas. Both the diversity of habitats and

histories of drainage evolution have resulted in a unique

and species-rich aquatic biota within the OzarkOuachita Highlands.

115
ecological-hydrologic units were recognized within the

four ecological sections. The team categorized an

additional 25 hydrologic units or watersheds that extended outside the borders of the Assessment area as

“peripheral,” making a total of 86 ecological-hydrologic

units within the aquatic study area (fig. 2.17).

The team noted freshwater mussels as present or

absent within each ecological-hydrologic unit and, using

the conservation rank for individual species given by

Williams and others (1993), rated them as (1) currently

stable, (2) of special concern, (3) threatened, or (4)

endangered. Finally, the team combined the ecologicalhydrologic units into their respective hydrologic units

with associated presence or absence and conservationrank data. They omitted the introduced Asian clam and

zebra mussel from these analyses. Only data for

existing freshwater mussels (i.e., records of live individuals or fresh dead shells taken within the past 30

years) were used in this analysis. Nomenclature and

species concepts generally follow Turgeon and others

(1988), as modified by Williams and others (1993).

The team analyzed diversity of freshwater mussels

using species richness, conservation-rank species

richness, species density, and conservation-rank species

density. Unionacean bivalve richness is defined as the

total number of freshwater mussel species within an

ecological-hydrologic unit or hydrologic unit. Ecologicalhydrologic and hydrologic units vary in areal extent, and

freshwater mussel richness may increase as stream

size, stream length, or drainage area increases.

To examine the effect of drainage area size, the

Aquatic Team divided freshwater mussel richness by

drainage area size to produce freshwater mussel density

values (expressed as density per 100 mi2

) for each unit.

The team totaled species conservation ranks for both

ecological-hydrologic and hydrologic units to arrive at

the conservation-rank species richness. For example, if

an ecological-hydrologic unit contained one stable

species (rank = 1), one species of special concern (rank

= 2), and one threatened or endangered species (rank =

3), then the conservation-rank species richness for that

unit would be 6 (1 + 2 + 3 = 6). The team then divided

conservation-rank species richness by drainage unit

area to determine conservation-rank species density.

Forty-five hydrologic units and 47 ecologicalhydrologic units had sufficient data to use for analysis

 Key Findings

 1. Seventy-three species of native freshwater mussels

representing 37 genera occur within the Assessment area. Eleven species are endemic to the

Assessment area, and there are two introduced

species—the Asian clam and the zebra mussel.

 2. Twenty-four freshwater mussel species are widely

distributed across the Assessment area; 16 species

occurring within the Assessment area are restricted to streams draining the Ozark Highlands,

and 8 species are restricted to streams draining the

Ouachita Mountains.

 3. North American conservation status rankings for

freshwater mussel species in the Assessment area

reveal that 40 species are considered currently

stable, 18 species are of special concern, 9 are

ranked as threatened, and 6 are listed as

endangered.

 4. Ecological-hydrologic units with relatively high

species richness and density occur primarily in tierlike clusters in the northeastern, central, and

southern portions of the Assessment area and

appear to be associated with hydrologic units

possessing both headwater and main stem habitats.

 5. The Aquatic Team calculated a relative importance

index value to rank hydrologic units in terms of

combined mussel species richness, species density,

and habitat availability for rare species. The five

highest ranking hydrologic units were the Spring

and Strawberry Rivers (Upper Black River Basin),

the Bourbeuse and Big Rivers (both in the

Meramec River Basin), and the Upper Ouachita

River (Ouachita-Saline River Basin).

Data Sources and Methods of Analysis

As in the preceding section—“Diversity of Fishes”—

the Aquatic Team subdivided each of the major drainages within the Assessment area using the watersheds

indicated in Chapter 1 (fig. 1.2). The team further

subdivided 32 of the 50 hydrologic units within the

Assessment area by overlaying ecological unit boundaries of the Ozark Highlands, Boston Mountains,

Arkansas Valley, and Ouachita Mountains. Sixty-one

116
of freshwater mussel spatial patterns (species distribution), species richness, and density. Three levels of

relative richness and density were recognized among

ecological-hydrologic and hydrologic units: primary,

secondary, and tertiary. Ecological-hydrologic and

hydrologic unit values for richness, density, conservation-rank richness, and conservation-rank density were

sorted and ranked, and levels were assigned based on

breaks in sequence. The Aquatic Team assigned

primary levels to grouped ecological-hydrologic and

hydrologic units with the highest parameter values

(e.g., for richness and density), secondary levels to the

next highest natural group of units, and tertiary levels to

the remaining units. Hence, primary levels approximate

values in the fourth quartile (top 25 percent); secondary

levels, values in the third quartile (second 25 percent);

and tertiary levels, values in the first and second

quartiles (bottom 50 percent). The team plotted species

richness, species density, and conservation-rank

species richness on both ecological-hydrologic and

hydrologic maps of the Assessment area to show

patterns of distribution, richness, and density. Individual

rank orders of hydrologic units for species richness,

species density, conservation-rank species richness,

and conservation-rank species density were added

together to provide a value of the relative importance

of hydrologic units as a freshwater mussel habitat in

the Assessment area.

The Aquatic Team determined distributions of

freshwater mussels within ecological-hydrologic units

from an array of data sources. Johnson (1980) presented mussel presence or absence data for drainages

encompassing much of the Assessment area. For

drainages in Missouri, dot distribution maps provided by

Oesch (1984) were the primary data source. The team

used Buchanan (1980) extensively to determine mussel

distributions within the Meramec River Basin. Gordon

(1980) and Clarke and Obermeyer (1996) provided data

about mussel distribution in the Spring and Elk Rivers

(Neosho-Illinois Basin) in Missouri. Warren (1991)

discussed the mussels of the upper Eleven Point River

(Upper Black River Basin). Gordon and others (1980)

summarized the distributional data for Arkansas mussels, and Gordon (1980) discussed the systematics and

zoogeography (geographic distribution of animals) of the

Mollusca in Arkansas.

Several studies of mussels have taken place in the

large Upper White and Upper Black River drainages of

Arkansas. Freshwater mussel distributions for the

Spring and Black Rivers were reported by the Arkansas

Highway and Transportation Department (AR HTD

1984), Gordon and others (1984), Miller and Nelson

(1984), Miller and Hartfield (1986), Rust (1993), and

Davidson and others (1997). Rust (1993) also surveyed

mussel distributions and population structures in portions

of the Strawberry and Current Rivers. Buchanan (1993)

and Sietman and Sadler (1994) surveyed selected sites

in northeast Arkansas and southwest Missouri to

monitor the declining status of the Curtis pearlymussel.

Meek and Clark (1912) first studied the distribution of

freshwater mussels in the Buffalo River, and Harris

(1996) resurveyed the same Buffalo River reaches to

determine if population densities and distributions had

remained stable. Miller and Harris (1987), Harris (1987,

1994b, 1995), and Christian (1995) studied mussel

distributions in the main stem of the White River

downstream of its confluence with the Black River.

Gordon (1980) surveyed the mussels of the White River

upstream from Beaver Reservoir, and Gordon (1982)

summarized the available data for the main stem of the

White River in Arkansas and Missouri. Freshwater

mussel distributions within the Little Red River (Upper

White River Basin) were documented by Clarke (1987)

and Harris (1992a, 1993).

Little published data are available for mussel distributions in rivers and streams draining the Arkansas

Valley. Relatively large Arkansas River tributaries such

as the Illinois Bayou, Fourche La Fave River, Petit Jean

River, Point Remove Creek, Cadron Creek, Maumelle

River, and Little Maumelle River have not been surveyed to determine mussel species composition and

distribution. Limited data about mussel distribution are

available for the Neosho River of Oklahoma, e.g.,

Branson (1973, 1982, 1983, 1984), White (1977),

Shepard and Covich (1982), Mather (1990), and

Vaughn (1996a). Gordon (1979) and Harris (1991c,

1997b) surveyed mussel distributions within the Illinois

River (Neosho-Illinois Basin) in Arkansas, and Vaughn

(1995) provided distributional data for the Oklahoma

portion of the Illinois River. Gordon (1980, 1985)

surveyed the mussels of Frog Bayou, and Stoeckel and

others (1996) investigated the mussel fauna of the

117
Mulberry River (Frog-Mulberry watershed). Davidson

(1997) surveyed the Ozark and Dardanelle reservoirs

of the Arkansas River (also known as the KerrMcClellan Navigation System) for mussels, and Harris

(1991a) surveyed a portion of Dardanelle Reservoir.

Harris (1992b, 1994c, respectively) also surveyed the

mussel populations in a short reach of the South

Fourche La Fave River and tributaries (Arkansas River

Basin) and the freshwater mussel distribution in the

Arkansas reach of the Poteau River.

Freshwater mussel distributions in the Kiamichi-Little

River drainage of Oklahoma were taken from Branson

(1982, 1983, 1984), Clarke (1987), Mehlhop and Miller

(1989), Vaughn and others (1993, 1994, 1996), Vaughn

and Pyron (1995), and Vaughn (1996a, 1996b, 1997).

Gordon and Harris (1983) and Clarke (1987) studied the

mussels of the Red River and tributaries in southwestern Arkansas.

Mussels of the Ouachita River drainage were first

reported by Wheeler (1918); Gordon and Harris (1983)

summarized the results of surveys in several Ouachita

River tributaries. Harris and Gordon (1988) provided the

most comprehensive data set regarding mussels of the

upper Ouachita River system during their status survey

of the Arkansas fatmucket. Additional studies (Harris

1989a, 1991b, 1994a; Burns and McDonnell 1992a,

1992b) to elucidate the status of the Arkansas

fatmucket provided data about the distribution of mussel

species associates. The mussels of portions of the Little

Missouri and Ouachita River main stems were surveyed

by Davidson (1997) and Posey (1997).

Distributional data for mussels in the Upper St. Francis

River came primarily from Oesch (1984) and Ecological

Consultants, Inc. (1984). Additional distributions in the St.

Francis River Basin were obtained from Ahlstedt and

Jenkinson (1987) and Jenkinson and Ahlstedt (1987

[synthesized in Ahlstedt and Jenkinson (1991)]).

Patterns and Trends

Composition of freshwater mussel species. The

Aquatic Team determined that 73 native mussel species

representing 37 genera (the first part of each species

name) occur within the Assessment area (table 2.13).

Twenty-one genera (57 percent) are represented by a

single species. The genera having the most species

within the Assessment area are Lampsilis and

Quadrula, represented by 11 and 7 species, respectively.

Within the subfamilies of the Unionidae, the following

number of species occur in the Assessment area: 37

lampsilines, 23 amblemines, 12 anodontines, and 1

cumberlandine (table 2.13).

North American conservation ranks of the 73 native

species occurring within the Assessment area (Williams

and others 1993) reveal that 40 are considered stable, 18

are of special concern, and 9 are federally listed as

threatened and 6 as endangered (table 2.13). Average

species richness for the 10 major river basins ranged

from a high of 51 in the Upper Black River Basin to a

low of 31 in the Upper St. Francis River Basin. In

descending order, average species richness for the

remaining 8 major basins was as follows: Kiamichi-Little

(49), Meramec (47), Ouachita (47), Upper White (47),

Osage (45), Neosho-Grand (39), Arkansas (35), and

Gasconade (33). Twenty-four species are distributed

broadly across the Assessment area—mucket, elktoe,

threeridge, spike, fatmucket, threehorn wartyback, round

pigtoe, giant floater, monkeyface, pimpleback, mapleleaf,

squawfoot, lilliput, pistolgrip, fawnsfoot, deertoe, fragile

papershell, butterfly, yellow sandshell, fluted-shell, paper

pondshell, pondhorn, washboard, and spectaclecase.

Analysis of species distributions within the Assessment area showed that there are 16 species of Ozarkian

fauna found in the Ozark Highland streams of the

Missouri, Neosho, St. Francis, and/or White River

systems: the Arkansas broken-ray, bleedingtooth mussel,

Curtis pearlymussel, elephant-ear, ellipse, long-solid,

Neosho mucket, Ohio pigtoe, Ozark pigtoe, pink

heelsplitter, purple wartyback, salamander mussel,

sheepnose, slippershell, snuffbox, and speckled pocketbook. The elephant-ear and sheepnose mussels were

restricted to the Missouri River system; the long-solid,

Curtis pearlymussel, Ohio pigtoe, and speckled pocketbook were found only in White River system streams;

and the Neosho mucket was restricted to the Neosho

River Basin.

The Ouachita fauna of the Assessment area was

composed of those species found in the Ouachita

Mountains streams of the Red River, Ouachita River,

and/or Arkansas River systems. This fauna included the

following eight species: Arkansas fatmucket, Louisiana

fatmucket, Ouachita creekshell, Ouachita rock-pocketbook, sandbank pocketbook, southern mapleleaf,

southern pocketbook, and winged mapleleaf. Most of

118
Table 2.13—Native and introduced mussels of the Ozark-Ouachita Highlands and their conservation status

 Conservation rank

Family Intro- Currently Special Threat- EndanSubfamily Species Common name Native Endemic duced stable concern ened gered

Corbiculidae Corbicula fluminea Asian clam X

Dreissenidae Dreissena polymorpha Zebra mussel X

Unionidae

Ambleminae Amblema plicata Threeridge X X

Ambleminae Cyclonaias tuberculata Purple wartyback X X

Ambleminae Elliptio crassidens Elephant-ear X X

Ambleminae Elliptio dilatata Spike X X

Ambleminae Fusconaia ebena Ebonyshell X X

Ambleminae Fusconaia flava Wabash pigtoe X X

Ambleminae Fusconaia ozarkensis Ozark pigtoe X X X

Ambleminae Fusconaia subrotunda Long-solid X X

Ambleminae Megalonaias nervosa Washboard X X

Ambleminae Plectomerus dombeyanus Bankclimber X X

Ambleminae Plethobasus cyphus Sheepnose X X

Ambleminae Pleurobema coccineum Round pigtoe X X

Ambleminae Pleurobema cordatum Ohio pigtoe X X

Ambleminae Pleurobema pyramidatum Pyramid pigtoe X X

Ambleminae Quadrula apiculata Southern mapleleaf X X

Ambleminae Quadrula cylindrica Rabbitsfoot X X

Ambleminae Quadrula fragosa Winged mapleleaf X X

Ambleminae Quadrula metanevra Monkeyface X X

Ambleminae Quadrula nodulata Wartyback X X

Ambleminae Quadrula pustulosa Pimpleback X X

Ambleminae Quadrula quadrula Mapleleaf X X

Ambleminae Tritogonia verrucosa Pistolgrip X X

Ambleminae Uniomerus tetralasmus Pondhorn X X

Anodontinae Alasmidonta marginata Elktoe X X

Anodontinae Alasmidonta viridis Slippershell X X

Anodontinae Anodonta suborbiculata Flat floater X X

Anodontinae Anodontoides ferussacianus Cylindrical papershell X X

Anodontinae Arcidens confragosus Rock-pocketbook X X

Anodontinae Arkansia wheeleri Ouachita rock-pocketbook X X X

Anodontinae Lasmigona complanata White heelsplitter X X

Anodontinae Lasmigona costata Fluted shell X X

Anodontinae Pyganodon grandis Giant floater X X

Anodontinae Simpsonaias ambigua Salamander mussel X X

Anodontinae Strophitus undulatus Squawfoot X X

Anodontinae Utterbackia imbecillis Paper pondshell X X

Cumberlandinae Cumberlandia monodonta Spectaclecase X X

Lampsilinae Actinonaias ligamentina Mucket X X

Lampsilinae Cyprogenia aberti Western fanshell X X X

Lampsilinae Ellipsaria lineolata Butterfly X X

Lampsilinae Epioblasma curtisi Curtis pearlymussel X X X

Lampsilinae Epioblasma triquetra Snuffbox X X

Lampsilinae Lampsilis abrupta Pink mucket X X

Lampsilinae Lampsilis cardium Pocketbook X X

Lampsilinae Lampsilis hydiana Louisiana fatmucket X X

Lampsilinae Lampsilis ornata Southern pocketbook X X

Lampsilinae Lampsilis powelli Arkansas fatmucket X X X

Lampsilinae Lampsilis rafinesqueana Neosho mucket X X X

Lampsilinae Lampsilis reeveiana Arkansas broken-ray X X X

Lampsilinae Lampsilis satura Sandbank pocketbook X X

Lampsilinae Lampsilis siliquoidea Fatmucket X X

Lampsilinae Lampsilis streckeri Speckled pocketbook X X X

Lampsilinae Lampsilis teres Yellow sandshell X X

Lampsilinae Leptodea fragilis Fragile papershell X X

(continued)

119
these species have primarily southern distributions and

may also be found in Gulf Coastal Plain and Mississippi

Alluvial Plain streams. The winged mapleleaf has a

somewhat unique distributional pattern, with disjunct

relict populations (isolated populations) apparently

remaining in the upper Mississippi River Valley outside

the Assessment area and in the Kiamichi and Ouachita

Rivers within the Assessment area.

The least widely distributed freshwater mussels in

the Assessment area were the cylindrical papershell,

known only from the Bourbeuse River hydrologic unit;

the Curtis pearlymussel, which persists only in the

Current River hydrologic unit; and the speckled pocketbook, which is endemic to the Little Red River hydrologic unit (Upper White River Basin).

Mussels species richness and density. Data for

mussel species richness and species density were

available for 47 of 61 ecological-hydrologic units within

the Assessment area (77 percent). When peripheral

ecological-hydrologic units were included, sufficient

data were available for 67 of the 86 total ecologicalhydrologic units (78 percent). When ecologicalhydrologic units were combined within their respective

hydrologic units, data were available for 45 of 50

hydrologic associated with the Assessment area units

(90 percent).

Ecological-hydrologic units. The species richness

mean was 24.5 mussel species per ecological-hydrologic

unit within the Assessment area (table 2.14). Of the

ecological-hydrologic units for which data were available

within the Assessment area, 53.2 percent (25 of 47 units)

have 25 or more species. The average species richness

was highest for ecological-hydrologic units in the Ozark

Highlands (28 species in 28 units) and Boston Mountains

(21.8 species in 4 units). Species density was highest for

ecological-hydrologic units in the Ozark Highlands (3.1

species per 100 mi2

 in 28 units), Boston Mountains (2.7

species per 100 mi2

 in 4 units), and Ouachita Mountains

(2.2 species per 100 mi2

 in 10 units) (table 2.14).

The distribution of ecological-hydrologic units with

respect to species richness levels—primary (6 units with

a range of 35 to 46 species), secondary (19 units with a

range of 25 to 33 species), and tertiary (22 units with a

range of 7 to 24 species)—revealed that one large

geographically contiguous area and several smaller,

separate areas of high species richness (primary and

secondary levels) are within the Assessment area (fig.

2.21). The six ecological-hydrologic units with primary

Table 2.13—Native and introduced mussels of the Ozark-Ouachita Highlands and their conservation status (continued)

 Conservation rank

Family Intro- Currently Special Threat- EndanSubfamily Species Common name Native Endemic duced stable concern ened gered

Lampsilinae Leptodea leptodon Scaleshell X X

Lampsilinae Ligumia recta Black sandshell X X

Lampsilinae Ligumia subrostrata Pondmussel X X

Lampsilinae Obliquaria reflexa Threehorn wartyback X X

Lampsilinae Obovaria jacksoniana Southern hickorynut X X

Lampsilinae Obovaria olivaria Hickorynut X X

Lampsilinae Potamilus alatus Pink heelsplitter X X

Lampsilinae Potamilus ohiensis Pink papershell X X

Lampsilinae Potamilus purpuratus Bleufer X X

Lampsilinae Ptychobranchus occidentalus Ouachita kidneyshell X X X

Lampsilinae Toxolasma lividus Purple lilliput X X

Lampsilinae Toxolasma parvus Lilliput X X

Lampsilinae Toxolasma texasensis Texas lilliput X X

Lampsilinae Truncilla donaciformis Fawnsfoot X X

Lampsilinae Truncilla truncata Deertoe X X

Lampsilinae Venustaconcha ellipsiformis Ellipse X X

Lampsilinae Venustaconcha pleasi Bleedingtooth mussel X X X

Lampsilinae Villosa arkansasensis Ouachita creekshell X X X

Lampsilinae Villosa iris Rainbow X X

Lampsilinae Villosa lienosa Little spectaclecase X X

Source: see “Data Sources and Methods of Analysis” of this section.

120
Table 2.14—Average mussel species richness and density for sections within the Assessment area

Number of

Conservation- ecologicalConservation-rank rank species hydrologic

Section or area Richness species richness Density density units

 - - Species per 100 mi2

 - -

Ozark Highlands 28.0 42.0 3.1 4.5 28

Boston Mountains 21.8 31.5 2.7 3.7 4

Arkansas Valley 14.0 15.0 1.7 1.8 5

Ouachita Mountains 21.1 29.2 2.2 2.9 10

Assessment area 24.5 35.5 2.7 3.8 47

Peripheral area 26.1 36.2 13.4 18.5 20

All ecological-hydrologic units 25.0 35.7 5.9 8.2 67

Figure 2.21—Levels of native freshwater mussel species richness by ecological-hydrologic unit.

Species richness

Primary

Secondary

Tertiary

Outside units or insufficient data

Oklahoma

Arkansas

Missouri

121
levels for species richness are all in the Ozark Highlands ecological section. They include three Upper

Black River Basin units—Spring River (OZ) (46

species), Current River (OZ) (42 species), and Strawberry River (OZ) (39 species)—the Upper White River

Basin’s Bull Shoals Lake (OZ) (35 species), and the

Meramec River drainage units—Meramec River (OZ)

(39 species) and Bourbeuse River (OZ) (37 species).

Ecological-hydrologic units of the Upper Black, St.

Francis, Meramec, and Gasconade River Basins, located

in the northeastern quarter of the Assessment area, form

the major contiguous center for species richness. Ecological-hydrologic units of the Kiamichi-Little River and

Ouachita-Saline River Basins draining southward from

the Ouachita Mountains into the western Gulf Coastal

Plain form a southern center of relatively high species

richness. Four ecological-hydrologic units in the NeoshoIllinois and Upper White River Basins form an interior

area of species richness that spans portions of the Ozark

Highlands and Boston Mountains ecological sections. A

third smaller center of relatively high species richness

occurs in upstream tributaries to the Osage River Basin in

the northwestern portion of the Assessment area.

Conservation-rank species richness values of ecological-hydrologic units—obtained by summing species

conservation ranks (1 = currently stable, 2 = of special

concern, 3 = threatened, 4 = endangered) for each

species present—showed a pattern that is similar to the

analysis just shown (fig. 2.22). These values ranged

from 8 to 76 (table 2.15), with an average conservation

Figure 2.22—Levels of freshwater mussel conservation-rank species richness by ecological-hydrologic unit.

Conservation-rank species richness

Primary

Secondary

Tertiary

Outside units or insufficient data

Oklahoma

Arkansas

Missouri

122
Table 2.15—Freshwater mussel species richness and density, conservation-rank values, and total endemics

within the Assessment area by ecological-hydrologic unit

Conservation- ConservationRiver basin Watershed Species Species rank species rank species Endemic

Ecological-hydrologic unit name code (HUC) Area richness density richness density species

Mi2 Number Number per

per 100 100 mi2

mi2

Osage River Basin

Harry S. Truman Reservoir-OZ 10290105 497 26 5.2 34 6.8 1

Harry S. Truman Reservoir-OA 10290105 714 22 3.1 26 3.6 1

Sac-OZ 10290106 1,716 27 1.6 41 2.4 3

Sac-OA 10290106 255 18 7.1 22 8.6 1

Pomme de Terre-OZ 10290107 848 25 3.0 34 4.0 3

South Grand-OZ 10290108 89 14 15.7 16 18.0 1

South Grand-OA 10290108 1,959 22 1.1 26 1.3 0

Lake of the Ozarks-OZ 10290109 1,385 19 1.4 21 1.5 0

Niangua-OZ 10290110 1,031 27 2.6 38 3.7 3

Lower Osage-OZ 10290111 952 33 3.5 46 4.8 2

Lower Osage-OA 10290111 124 22 17.7 29 23.4 0

Gasconade River Basin

Upper Gasconade-OZ 10290201 1,788 22 1.2 30 1.7 1

Big Piney-OZ 10290202 756 12 1.6 17 2.2 2

Lower Gasconade-OZ 10290203 865 28 3.2 43 5.0 1

Lower Gasconade-OA 10290203 170 30 17.7 48 28.2 1

Meramec River Basin

Meramec-OZ 07140102 1,815 39 2.2 63 3.5 3

Meramec-OA 07140102 345 41 11.9 62 18.0 2

Bourbeuse-OZ 07140103 785 37 4.7 55 7.0 2

Bourbeuse-OA 07140103 52 32 61.2 47 90.4 1

Big-OZ 07140104 806 27 3.4 40 5.0 3

Big-OA 07140104 156 28 18.0 40 25.6 1

Upper St. Francis River Basin

Upper St. Francis-OZ 08020202 1,298 31 2.4 48 3.7 3

Neosho-Illinois River Basin

Lake O’ the Cherokees-OZ 11070206 586 — — — — —

Lake O’ the Cherokees-OA 11070206 334 12 3.6 13 3.9 0

Spring-OZ 11070207 1,793 24 1.3 36 2.0 3

Spring-OA 11070207 785 20 2.5 26 3.3 1

Elk-OZ 11070208 1,031 23 2.2 39 3.8 5

Lower Neosho-OZ 11070209 1,028 — — — — —

Lower Neosho-BM 11070209 238 — — — — —

Lower Neosho-OA 11070209 944 — — — — —

Illinois-OZ 11110103 1,329 30 2.3 42 3.2 4

Illinois-BM 11110103 321 — — — — —

Arkansas River Basin

Dirty-Greenleaf-BM 11110102 288 — — — — —

Dirty-Greenleaf-AV 11110102 229 — — — — —

Dirty-Greenleaf-OA 11110102 273 — — — — —

Robert S. Kerr Reservoir-BM 11110104 732 — — — — —

Robert S. Kerr Reservoir-AV 11110104 1,074 — — — — —

Poteau-OM 11110105 1,904 28 1.5 31 1.6 1

Frog-Mulberry-BM 11110201 719 20 2.8 28 3.9 0

Frog-Mulberry-AV 11110201 539 18 3.3 19 3.5 0

Dardanelle Reservoir-BM 11110202 668 — — — — —

Dardanelle Reservoir-AV 11110202 1,193 18 1.5 19 1.6 0

Lake Conway-Point Remove-AV 11110203 1,137 7 0.6 8 0.7 0

Petit Jean-AV 11110204 1,090 15 1.4 16 1.5 0

(continued)

123
Table 2.15—Freshwater mussel species richness and density, conservation-rank values, and total endemics

within the Assessment area by ecological-hydrologic unit (continued)

Conservation- ConservationRiver basin Watershed Species Species rank species rank species Endemic

Ecological-hydrologic unit name code (HUC) Area richness density richness density species

Mi2 Number Number per

per 100 100 mi2

mi2

Arkansas River Basin (continued)

Cadron-AV 11110205 769 12 1.6 13 1.7 0

Fourche La Fave-OM 11110206 1,119 20 1.8 22 2.0 0

Lower Arkansas-Maumelle-AV 11110207 280 — — — — —

Lower Arkansas-Maumelle-OM 11110207 197 — — — — —

Lower Arkansas-Maumelle-OA 11110207 630 — — — — —

Kiamichi-Little River Basin

Kiamichi-OM 11140105 1,316 33 2.5 49 3.7 3

Kiamichi-OA 11140105 506 27 5.3 39 7.7 2

Upper Little-OM 11140107 1,010 21 2.1 28 2.8 2

Upper Little-OA 11140107 399 29 7.3 39 9.8 3

Mountain Fork-OM 11140108 787 13 1.7 17 2.2 1

Mountain Fork-OA 11140108 69 24 35.0 31 44.9 1

Lower Little-OM 11140109 674 6 0.9 10 1.5 1

Lower Little-OA 11140109 1,301 36 2.8 54 4.2 3

Ouachita-Saline River Basin

. Ouachita Headwaters-OM 08040101 1,546 28 1.8 41 2.7 4

Upper Ouachita-OM 08040102 673 25 3.7 40 4.0 4

Upper Ouachita-OA 08040102 1,089 37 3.4 53 4.9 3

Little Missouri-OM 08040103 613 12 2.0 20 3.3 3

Little Missouri-OA 08040103 1,484 29 2.0 44 3.0 2

Upper Saline-OM 08040203 673 25 3.7 34 5.1 3

Upper Saline-OA 08040203 1,037 39 3.8 55 5.3 4

Upper White River Basin

Beaver Reservoir-OZ 11010001 1,610 30 1.9 44 2.7 5

Beaver Reservoir-BM 11010001 946 29 3.1 43 4.5 5

James-OZ 11010002 1,448 23 1.6 36 2.5 4

Bull Shoals Lake-OZ 11010003 2,600 35 1.4 59 2.3 6

Middle White-OZ 11010004 1,034 — — — — —

Middle White-BM 11010004 407 11 2.7 13 3.2 0

Middle White-OA 11010004 34 17 50.5 23 67.6 0

Buffalo-OZ 11010005 653 22 3.4 37 5.7 5

Buffalo-BM 11010005 689 — — — — —

North Fork White-OZ 11010006 1,836 16 0.9 28 1.5 5

Little Red-BM 11010014 1,320 27 2.1 42 3.2 5

Little Red-AV 11010014 411 — — — — —

Little Red-OA 11010014 90 — — — — —

Upper Black River Basin

Upper Black-OZ 11010007 1,439 32 2.2 52 3.6 6

Upper Black-OA 11010007 471 23 4.9 31 7.4 0

Current-OZ 11010008 2,453 42 1.7 62 2.5 6

Current-OA 11010008 172 14 8.2 16 9.3 0

Lower Black-OZ 11010009 490 33 6.7 46 9.4 1

Lower Black-OA 11010009 289 — — — — —

Spring-OZ 11010010 1,217 46 3.8 76 6.2 5

Eleven Point-OZ 11010011 1,202 22 1.8 32 2.7 5

Strawberry-OZ 11010012 789 39 4.9 61 7.9 5

HUC = hydrologic unit code; mi2

 = square mile; OZ = Ozark Highlands; BM = Boston Mountains; AV = Arkansas Valley;

OM = Ouachita Mountains; OA = Outside the Highlands Assessment ecological sections; — = insufficient data.

124
rank of 35.5 per unit in the Assessment area (table

2.14). Conservation-rank species richness values in

ecological-hydrologic units are as follows—primary (7

units with a range of 52 to 76), secondary (18 units with

a range of 36 to 49), and tertiary (22 units with a range

of 8 to 35). This distribution showed that the high

richness area in the northeastern quarter of the Assessment area persisted, as did the smaller southern center

of richness. The interior and upper Osage tributary areas

of high species richness coalesced in the conservationrank species richness analysis to form a broader western

Ozark center of high conservation-rank species richness.

The five ecological-hydrologic units with the highest

conservation-rank species richness in the Assessment

area were the Spring (OZ) (76), Current (OZ) (62), and

Strawberry (OZ) (61) units, of the Upper Black River

Basin and the Meramec (OZ) (63) and the Bull Shoals

(OZ) (59) units of the Upper White River Basin. (Of

the 11 highest ranking ecological-hydrologic units, one

was not in the Ozark Highlands—the Kiamichi in the

Ouachita Mountains.) The freshwater mussel communities of the 11 highest ranking ecological-hydrologic units

were characterized by high numbers of species (31 to

46), of which 5 to 7 species are considered threatened

or endangered.

The density of freshwater mussel species varied

among ecological-hydrologic units of the Assessment

area. The average species density for 47 of the ecological-hydrologic units was 2.7 species per 100 mi2

 (table

2.14). The species density distribution of ecologicalhydrologic units in the Assessment area shows northern

and central centers of high species density (fig. 2.23).

The primary level has 5 units with a range of 4.7 to 15.7

species per 100 mi2

; the secondary level has 11 units

with a range of 2.8 to 3.8 species per 100 mi2

; and the

tertiary level has 31 units with a range of 0.6 to 2.7

species per 100 mi2

. Ecological-hydrologic units with

primary levels of species density had relatively small

drainage areas (89 to 789 mi2

) and species richness

values ranging from 14 to 39. Seven of the 10 smallest

ecological-hydrologic had primary or secondary levels of

species density. However, regression of species richness

with drainage area was not statistically significant for

ecological-hydrologic units.

Conservation-rank species density for ecologicalhydrologic units inside the Assessment area ranged

from 0.7 to 18.0 species per 100 mi2

 (table 2.15), with

an average value of 3.8 species per 100 mi2

. The

distribution of ecological-hydrologic units with primary

(7 units with a range 5.7 to 18.0 species per 100 mi2

);

secondary (15 units with a range of 3.5 to 5.1 species

per 100 mi2

); and tertiary (25 units with a range of 0.7

to 3.3 species per 100 mi2

) levels of conservation-rank

species density within the Assessment area illustrates a

pattern similar to species density with distinct northern

peripheral, central, and southern concentrations (not

shown here).

Hydrologic units. The most species-rich hydrologic

units were the Spring (Upper Black River Basin) with 46

species and the Meramec with 44 species, followed

closely by the Current (Upper Black River Basin) and

Upper Ouachita hydrologic units (43 and 42 species,

respectively) (table 2.16). Four of the hydrologic units

with relatively low species richness (North Fork White

River, Dardanelle Reservoir, Lake of the Ozarks, and

Middle White River) have been ecologically altered by

major river channel reservoirs or adverse biological

effects that affect aquatic habitats downstream of dams.

(The “adverse biological effects” are associated with

hypolimnetic releases—discharges from reservoirs of

deeper, colder, less oxygenated water.) The average

species richness was 28.7 per unit for 45 of the

hydrologic units within the aquatic study area. The

distribution of hydrologic units in terms of species

richness was similar to that of ecological-hydrologic

units: primary (4 watersheds with a range of 42 to 46

species), secondary (19 watersheds with a range of 29

to 39 species), and tertiary (22 watersheds with a range

of 12 to 28 species). However, there was a more

pronounced southern tier of species-rich units for

southward draining Ouachita River and Red River

system tributaries (fig. 2.24).

Nineteen of the 23 hydrologic units exhibiting primary

or secondary levels of species richness were positioned

at ecotones between uplands of the Ouachita Mountains

or Ozark Highlands and lowlands of the West Gulf

Coastal Plain or the Mississippi Alluvial Basin. These

hydrologic units were enriched with species characteristically found in both tributaries and large rivers and thus

exhibited higher species richness.

Conservation-rank species richness values ranged from

13 to 76 (mean = 41.4) for the 45 hydrologic units analyzed in the aquatic study area (table 2.16). The distribution of hydrologic units for conservation-rank species

125
Figure 2.23—Levels of freshwater mussel species density by ecological-hydrologic unit.

Species density

Primary

Secondary

Tertiary

Outside units or insufficient data

Oklahoma

Arkansas

Missouri

richness—primary (11 watersheds with a range of 54 to

76), secondary (13 watersheds with a range of 41 to 50),

and tertiary (21 watersheds with a range of 13 to 39)—

was generally congruent with results for species richness.

Two centers of conservation-rank species richness were

evident among hydrologic units (fig. 2.25). The largest

centers of conservation-rank species richness were

located in the northeastern quarter and in the southernmost tier of hydrologic units of the Assessment area.

Freshwater mussel species density was highly

variable among hydrologic units (table 2.16), ranging

from 0.9 to 4.9; the average mussel species density was

2.1 species per 100 mi2

. Regression of species richness

with unit area was significant (P < 0.002). The relationship log (species richness) = 0.425 + 0.312 log (unit

area) accounted for only 20 percent of the species

richness. Species density in a hydrologic unit was

negatively correlated with unit area (k = -0.686, P <

0.0001). The distribution of hydrologic units in terms of

species density—primary (6 watersheds with a range of

3.6 to 4.9 species per 100 mi2

), secondary (11 watersheds with a range of 2.2 to 3.3 species per 100 mi2

),

126
Table 2.16—Mussel species richness and density, conservation-rank richness and density, index of relative importance, and overall

rank for watersheds within the aquatic study area

Species Conservation-rank Conservation-rank Index of relative Overall

River basin Watershed richness (rank Species density species richness species density importance (sum rank

Watershed name code (HUC) order) (rank order) (rank order) (rank order) of rank orders) ordera

 No. per 100 mi2 No. per 100 mi2

Osage River Basin

H.S. Truman Reservoir 10290105 28 (16) 2.3 (11) 36 (21) 3.0 (14) 62 22

Sac 10290106 29 (15) 1.5 (17) 43 (15) 2.2 (20) 67 24

Pomme de Terre 10290107 25 (18) 2.9 (8) 34 (23) 4.0 (8) 57 20

South Grand 10290108 24 (19) 1.2 (20) 30 (27) 1.5 (24) 90 30

Lake of the Ozarks 10290109 19 (23) 1.4 (18) 21 (30) 1.5 (24) 95 32

Niangua 10290110 27 (17) 2.6 (9) 38 (19) 3.7 (11) 56 19

Lower Osage 10290111 36 (8) 3.3 (6) 49 (11) 4.5 (6) 31 7

Gasconade River Basin

Upper Gasconade 10290201 22 (21) 1.2 (20) 30 (27) 1.7 (22) 90 30

Big Piney 10290202 12 (27) 1.6 (16) 17 (32) 2.3 (19) 94 31

Lower Gasconade 10290203 32 (12) 3.1 (7) 50 (10) 4.9 (5) 34 9

Meramec River Basin

Meramec 07140102 44 (2) 2.0 (13) 68 (2) 3.2 (13) 30 6

Bourbeuse 07140103 38 (6) 4.6 (2) 56 (7) 6.7 (2) 17 3

Big 07140104 37 (7) 3.8 (4) 57 (6) 5.9 (4) 21 4

Upper St. Francis River Basin

Upper St. Francis 08020202 31 (13) 2.4 (10) 48 (12) 3.7 (11) 46 14

Neosho-Illinois River Basin

Lake O’ the Cherokees 11070206 15 (26) 1.6 (16) 16 (33) 1.7 (22) 97 33

Spring 11070207 32 (12) 2.6 (9) 47 (13) 3.9 (9) 43 12

Elk 11070208 23 (20) 2.2 (12) 39 (18) 3.8 (10) 60 21

Lower Neosho 11070209 — — — — ——

Illinois 11110103 30 (14) 1.8 (15) 42 (16) 2.6 17) 62 22

Arkansas River Basin

Dirty-Greenleaf 11110102 — — — — ——

Robert S. Kerr Reservoir 11110104 — — — — ——

Poteau 11110105 28 (16) 1.5 (17) 31 (26) 1.6 (23) 82 28

Frog-Mulberry 11110201 25 (18) 2.0 (13) 33 (24) 2.6 (17) 72 26

Dardanelle Reservoir 11110202 18 (24) 1.0 (21) 19 (31) 1.0 (25) 101 36

Conway- Pt. Remove 11110203 — — — — ——

Petit Jean 11110204 15 (26) 1.4 (18) 16 (33) 1.5 (24) 101 36

Cadron 11110205 12 (27) 1.5 (17) 13 (34) 1.7 (22) 100 35

Fourche La Fave 11110206 21 (22) 1.9 (14) 27 (29) 2.4 (18) 83 29

Lower Ark-Maumelle 11110207 — — — — ——

Kiamichi-Little River Basin

Kiamichi 11140105 34 (10) 1.9 (14) 50 (10) 2.8 (15) 49 16

Upper Little 11140107 32 (12) 2.3 (11) 42 (9) 3.0 (14) 53 18

Mountain Fork 11140108 31 (13) 3.6 (5) 36 (21) 4.2 (7) 46 14

Lower Little 11140109 36 (8) 1.8 (15) 54 (9) 2.7 (16) 48 15

Ouachita-Saline River Basin

Ouachita Headwaters 08040101 28 (16) 1.8 (15) 41 (17) 2.7 (16) 64 23

Upper Ouachita 08040102 42 (4) 2.4 (10) 64 (3) 3.6 (12) 29 5

Little Missouri 08040103 32 (12) 1.5 (17) 50 (10) 2.4 (18) 57 20

Upper Saline 08040203 39 (5) 2.3 (11) 55 (8) 3.2 (13) 37 10

Upper White River Basin

Beaver Reservoir 11010001 33 (11) 1.3 (19) 47 (13) 1.8 (21) 64 23

James 11010002 23 (20) 1.6 (16) 35 (22) 2.4 (18) 76 26

Bull Shoals Lake 11010003 35 (9) 1.3 (19) 59 (5) 2.3 (19) 52 17

Middle White 11010004 21 (22) 1.4 (18) 27 (29) 1.8 (21) 90 30

Buffalo 11010005 22 (21) 1.6 (16) 37 (20) 2.8 (15) 72 26

(continued)

127
Table 2.16—Mussel species richness and density, conservation-rank richness and density, index of relative importance, and overall

rank for watersheds within the aquatic study area (continued)

Species Conservation-rank Conservation-rank Index of relative Overall

River basin Watershed richness (rank Species density species richness species density importance (sum rank

Watershed naame code (HUC) order) (rank order) (rank order) (rank order) of rank orders) ordera

 No. per 100 mi2 No. per 100 mi2

Upper White River Basin (continued)

North Fork White 11010006 16 (25) 0.9 (22) 28 (28) 1.5 (24) 99 34

Little Red 11010014 27 (17) 1.5 (17) 42 (16) 2.3 (19) 69 25

Upper Black River Basin

Upper Black 11010007 35 (9) 1.8 (15) 57 (6) 3.0 (14) 44 13

Current 11010008 43 (3) 1.6 (16) 64 (3) 2.4 (18) 40 11

Lower Black 11010009 33 (11) 4.2 (3) 46 (14) 5.9 (4) 32 8

Spring 11010010 46 (1) 3.8 (4) 76 (1) 6.2 (3) 9 1

Eleven Point 11010011 22 (21) 1.8 (15) 32 (25) 2.7 (16) 77 27

Strawberry 11010012 39 (5) 4.9 (1) 61 (4) 7.9 (1) 11 2

HUC = hydrologic unit code; mi2 = square mile; — = insufficient data. a Rank order identifies the order of importance with 1 being the highest, 34 the lowest.

Source: see “Data Sources and Methods of Analysis” of this section.

Figure 2.24—Levels of freshwater mussel species richness by watershed.

Species richness

Primary

Secondary

Tertiary

Insufficient data

Oklahoma

Arkansas

Missouri

128
and tertiary (28 watersheds with a range of 0.9 to 2.0

species per 100 mi2

)—was generally congruent with

that previously presented for ecological-hydrologic units,

with the exception that the southern tier of hydrologic

units increased in density level (fig. 2.26). These

increases were due to the addition of species from

ecological-hydrologic units outside of the Assessment

area, and included several large river mussel species

encountered in the ecotones between the Ouachita

Mountains and the Gulf Coastal Plain.

Conservation-rank species density values ranged

from 1.0 to 7.9 species per 100 mi2

 with an average of

3.1 (table 2.16). The hydrologic units exhibited primary

(6 watersheds with a range of 4.9 to 7.9 species per 100

mi2

), secondary (13 watersheds with a range of 3.0 to

4.5 species per 100 mi2

), and tertiary (25 watersheds

with a range of 1.0 to 2.8 per 100 mi2

) levels of conservation-rank density.

The Aquatic Team summed rank order values for

each species richness and species density index to give

an “index of relative importance” for each watershed

(lower sums in this column on table 2.16 indicate greater

richness and density). In the aquatic study area, this

index ranked 10 watersheds as having the greatest

Figure 2.25—Levels of freshwater mussel conservation-rank species richness by watershed.

Conservation-rank species richness

Oklahoma

Arkansas

Missouri

Primary

Secondary

Tertiary

Insufficient data

129
richness and density: 3 each in the Upper Black River

and Meramec River Basins, 2 in the Ouachita-Saline

River Basin, and 1 each in the Osage River and Gasconade River Basins. The Spring and Strawberry Rivers

(both in the Upper Black River Basin) received the

number one and two “overall rank,” respectively, for

watersheds within the aquatic study area. Both ranked

among the top five watersheds for each richness and

density category. The Spring River ranked first in both

species richness (46 species) and conservation-rank

species richness (value = 76), and the Strawberry River

ranked first in both species density (4.9 species per 100

mi2

) and conservation-rank density (7.9 per 100 mi2).

The Spring River mussel community included four

threatened species, two endangered species, and five

endemic species.

Endemic freshwater mussels. Johnson (1980)

identified 10 species as being endemic to the Interior

Highlands. In addition, Gordon (1980) and Gordon and

Harris (1983) discussed the distributional patterns and

zoogeography for Arkansas mussels and categorized

seven species found within Arkansas as Interior Highlands endemic species.

Using current species concepts, 11 species (15.1

percent of the native mussels) are endemic to the

Interior Highlands (table 2.13). Further inspection of

Figure 2.26—Levels of freshwater mussel species density by watershed.

Species density

Primary

Secondary

Tertiary

Insufficient data

Oklahoma

Arkansas

Missouri

130
these endemic species indicates three patterns of

endemism that coincide with ecological sections: Ozark

Highlands endemic species, Ouachita Mountains

endemic species, and endemic species common to both

ecological sections. Six species (Arkansas broken-ray,

bleedingtooth mussel, Curtis pearlymussel, Neosho

mucket, Ozark pigtoe, and speckled pocketbook) are

restricted to the Ozark Highlands; three species (Arkansas fatmucket, Ouachita creekshell, and Ouachita rockpocketbook) are found only in the Ouachita Mountains;

and two species (Ouachita kidneyshell and western

fanshell) occur in both the Ozark and Ouachita ecological sections.

At least one endemic mussel species was present in

38 of 47 ecological-hydrologic units in the Assessment

area for which data were available. Endemicity

averaged 2.6 endemic species per ecological-hydrologic unit. Primary levels of endemicity (11 units with a

range of 5 to 6 species) were associated with ecological-hydrologic units in the Upper White and Upper

Black River Basins (10 units) and the Neosho River

Basin (number = 1 unit) of the Ozark Highlands.

Secondary levels of endemicity (13 units with a range

of 3 to 4 species) occurred in the Osage (2 units) and

Meramec (2 units) Basins, the Upper White River

Basin (2 units), the Upper St. Francis River Basin

(1 unit), the Neosho-Illinois River Basin (1 unit), the

Kiamichi River-Little Basin (1 unit), and all four

ecological-hydrologic units of the Ouachita-Saline

River Basin within the Highlands.

Implications and Opportunities

Freshwater mussels have been described as an

imperiled fauna threatened by habitat destruction,

overutilization (for commercial or other purposes),

disease, predation, introduction of nonindigenous

species, pollution, hybridization, and restricted range

(Williams and others 1993). The single most important

cause of decline in mussel diversity and abundance has

been habitat destruction. Causes of this destruction have

ranged from the obvious—dams, dredging, and

channelization—to the subtler—siltation and contaminants. Erosion, caused in part by deforestation, poor

agricultural practices, and destruction of riparian zones,

has led to both increased silt loads and shifting, unstable

stream bottoms. While habitat destruction continues,

expansion of the distribution and numbers of

nonindigenous mollusks such as the Asian clam and

zebra mussel appears poised to destroy many remaining

native mussel populations (Williams and others 1993).

Several hydrologic units with high “relative importance” indices are either on federally managed land or

are within close proximity to such land. These include

the Upper Ouachita and Upper Saline watersheds

associated with the Ouachita National Forest and the

Big River and Meramec River watersheds associated

with the Mark Twain National Forest. Therefore,

activities on federally managed lands can affect some of

the best remaining populations of freshwater mussels

within the Assessment area. Activities potentially

harmful to freshwater mussels include timber management and road building and maintenance activities that

may adversely affect water quality by increasing

turbidity and sedimentation. A subtler—yet possibly

lethal impact to mussels on Federal lands—would be the

introduction of zebra mussels at recreational stream

access sites by boaters.

Habitat protection and good conservation practices

are essential to maintain existing freshwater mussel

populations. Managers must implement best management practices (BMP’s) when conducting timber

harvests, road building and maintenance, and/or other

construction activities near streams. Maintenance of

riparian zones along streams is important to good water

quality, nutrient levels, cover, and habitat—not only for

freshwater mussels but also for the intimately associated fish and macroinvertebrate communities.

Managers and scientists interested in the recovery

of freshwater mussel populations must understand

community structure and function and then seek to

reestablish key components that may have been

eliminated or diminished by human activities. The first

step to understanding community function is to understand the life cycle of each individual species. For

freshwater mussels, this begins with acquiring knowledge concerning the fish host(s) required for successful

reproduction; currently, the fish hosts of less than half

of the mussel species in the Assessment area are

known. Secondly, the interaction of physical and

biological habitat variables in viable mussel communities

is poorly understood. Additional research is needed to

131
determine the combination of biological and physicalchemical attributes required to establish and maintain

viable mussel communities. Partnerships among natural

resource agencies, scientists and resource specialists,

mussel researchers at academic institutions, and others

may be the most effective way to sustain the needed

research.

Preventing the introduction and spread of nuisance

species to aquatic systems within the Assessment area

is of increasing importance. A high priority is the

education of users of Federal lands and waters regarding the catastrophic effects of introduced species.

Partnerships among State and Federal resource agencies, academic institutions at all levels, and the media

are critical to successfully stemming the tide of invaders

such as the Asian clam and zebra mussel.

Diversity of Crayfishes

Question 2.6: What are the status and

distribution of crayfishes within the Assessment

area?

Decapod crustaceans in the families Astacidae,

Cambaridae, and Parastacidae, commonly known as

crayfishes or crawfishes, can be found nearly worldwide. Their highest diversity is in North America north of

Mexico (Taylor and others 1996). The Southern United

States harbors the most crayfish species, and within the

Ozark-Ouachita Highlands, crayfishes are one of the

most conspicuous and diverse components of the aquatic

fauna (Bouchard and Robison 1980, Pflieger 1996). The

Assessment area and immediately adjacent lowlands and

prairies support about 17 percent (at least 57) of the

crayfishes of the United States and Canada. Of the

combined crayfish fauna of Arkansas, Missouri, and

Oklahoma (Taylor and others 1996), 79 percent (about

72 taxa) occur within or immediately adjacent to the

Assessment area. Many crayfishes in the Assessment

area have extremely limited ranges (e.g., single springs

or cave systems) or may occur widely in one basin and

be absent from adjacent drainages. For example, within

the relatively rich crayfish fauna of the Ozark Highlands,

at least 16 species are unknown outside the area; many

of these species are confined to single hydrologic units

(Pflieger 1996).

Crayfishes, significant components of aquatic

ecosystems, are large invertebrates often found in

streams, rivers, and lakes. They facilitate important

ecological processes, sustain recreational and commercial bait fisheries, and are a profitable and popular food

(Taylor and others 1996, Pflieger 1996). Within the

Assessment area, crayfishes often make up a large

proportion of the biomass produced in aquatic systems

(Rabeni 1992) and provide a critical food resource for

stream fishes (Probst and others 1984). Nevertheless,

knowledge of the basic biology and distribution of

crayfishes in the Assessment area lags behind that of

other aquatic organisms such as fishes and mussels.

Recently, Pflieger (1996) published an excellent

synthesis of information on the distribution and biology

of the crayfishes of Missouri. That monograph along

with the work of Bouchard and Robison (1980) and

Hobbs (1989) formed the basis for this part of the

Assessment. A comprehensive monograph on the

biology and distribution of crayfishes of Arkansas is in

preparation.

Crayfishes occupy many aquatic habitats in the

Assessment area. Based on their usual or predominant

habitat, crayfishes can be divided into four broad (but

sometimes overlapping) categories: (1) stream dwellers; (2) swamp, marsh, and pond dwellers; (3) burrowers; or (4) cave dwellers (Pflieger 1996). Stream

dwellers predominate the crayfish fauna of the OzarkOuachita Highlands, but species in all categories are

represented. Several species usually associated with

lowlands have penetrated the periphery of the OzarkOuachita Highlands, particularly along the Arkansas

Valley (Bouchard and Robison 1980) and the interface

of the Ozark Highlands and Mississippi Alluvial Basin

(Pflieger 1996). The richness of crayfishes in the

Assessment area is a result not only of varied aquatic

habitats but also of the landscape and drainage patterns of its geologically ancient streams (Pflieger

1996).

132
 Key Findings

 1. Crayfish species representing 6 genera and 1

family (Cambaridae) are present in the OzarkOuachita Highlands Assessment area, and the

genera Orconectes (24 species), Procambarus

(13 species), and Cambarus (9 species) comprise

84 percent of the crayfish fauna in the 50 hydrologic units.

 2. Crayfish species richness averaged 5.9 crayfish

species per hydrologic unit with a range of from 2

to 14 species; however, most hydrologic units

showed diverse crayfish faunas, with 29 of 50 units

having crayfish richness values greater than 4

species.

 3. The southeastern Ouachita Mountains and an area

trending southwest to northeast from the western

Boston Mountains to the eastern Ozark Plateaus

showed primary or secondary levels of crayfish

richness (6 to 14 species).

 4. Crayfish density averaged 0.4 species per 100 mi2

of a hydrologic unit and ranged from 0.1 to 0.9; 17

of 50 hydrologic units had densities equal to or

exceeding 0.5 crayfish species per 100 mi2

.

 5. Concentrations of hydrologic units with primary

levels of crayfish density occurred along the

northeastern edge of the Assessment area (Middle

White unit, Upper St. Francis unit, and most units in

the Black River and Meramec drainages) and in

the southern part of the Assessment area (most

units in the Ouachita-Saline drainage and the

Lower Little unit of the Kiamichi-Little drainage).

 6. The Ozark-Ouachita Highlands area supports at

least 37 endemic crayfishes or 61 percent of the

region’s crayfish fauna; most of these endemic

species are confined to the Ozark Plateaus and

Boston Mountains (at least 22 endemic crayfishes),

but endemicity is also relatively high in the

Ouachita Mountains (at least 13 endemic crayfishes).

Data Sources and Methods of Analysis

To account for the distributions of crayfishes, the

Aquatic Team subdivided each of 10 major drainages

within the Assessment area according to hydrologic

units or watersheds. River basins and watersheds are

shown in figure 1.2. Fifty hydrologic units or watersheds

were recognized within the aquatic study area. Half of

these watersheds extend beyond the Assessment area

and contain portions of other ecological sections (e.g.,

the Mississippi Alluvial Basin). Within a particular

hydrologic unit, the team determined the presence or

absence of a crayfish species or subspecies primarily

from maps, distributional tables, and descriptions in

Williams (1954), Reimer (1969), Bouchard and Robison

(1980), Hobbs and Brown (1987), Hobbs and Robison

(1985, 1988, 1989), Hobbs (1989), Pflieger (1996),

Robison and Leeds (1996), and Taylor and others

(1996). The team also used these sources for species

regarded as endemic to the aquatic study area. With the

exception of Missouri (Pflieger 1996), no recent distributional monographs for crayfishes are available for

much of the study region; in particular, there are no

current maps of crayfish distributions for Arkansas and

Oklahoma. The status of a crayfish species reflects its

known historical presence within a hydrologic unit but

does not indicate its continued or present-day occurrence there. Available maps (e.g., Pflieger 1996)

depicted distributions by discrete points of occurrence,

allowing relatively unambiguous interpretation of

crayfish distributions. In cases where the Aquatic Team

could not interpret the location of data points or maps

were not available, the team attempted to identify

referenced site locations. In a limited number of cases,

reference data were unavailable or not interpretable; the

presence of a species in those hydrologic units was not

included in the final data set. Because of the lack of

detailed information on distribution, assignment to

hydrologic units may have resulted in an underestimation

of the range of some crayfish species, particularly those

within Arkansas or Oklahoma. Likewise, some crayfish

that occur predominantly in portions of hydrologic units

extending outside the Assessment area were included in

estimates of the species richness of those units. Scientific names are generally consistent with Taylor and

others (1996); less than one-quarter of crayfish taxa

have common names (Williams and others 1989a).

Because of uncertainty regarding the distribution of

subspecies, we treat Orconectes palmeri palmeri and

Orconectes palmeri longimanus under the species

name Orconectes palmeri (Penn 1957, Pflieger 1996).

133
The Aquatic Team analyzed diversity of crayfishes

using species richness, species density, and numbers of

endemic species. Species richness is the total number of

crayfishes within each hydrologic unit. Hydrologic units

vary in size, and richness often increases with an

increase in stream size or area drained (areal additivity).

To examine the effect of areal additivity, the team

divided species richness by the number of square miles

to produce species density values (times 100) for each

unit. Species richness, species density, and number of

endemic species were plotted on separate hydrologic

unit maps. Three levels of relative species richness,

density, and endemicity were recognized among hydrologic units: primary, secondary, and tertiary. Primary

levels were assigned to the 12 to 17 units (depending on

tied scores) with highest values, secondary levels to the

next highest 11 to 12 units, and tertiary values to the

remaining units. Hence, primary levels approximate

values in the fourth quartile; secondary levels, values in

the third quartile; and tertiary levels, values in the first

and second quartile.

Patterns and Trends

Composition of crayfish species. Crayfish faunal

composition is distributed unevenly among genera.

Present in the hydrologic units are 1 family

(Cambaridae) and 57 species or subspecies representing

6 genera (table 2.17): Cambarellus (2 species);

Cambarus (9 species); Fallicambarus (5 species);

Faxonella (2 species); Orconectes (24 species, two of

which are represented by 2 subspecies each); and

Procambarus (13 species). The crayfish genera

Orconectes, Procambarus, and Cambarus comprise

84 percent of the fauna in the 50 hydrologic units. The

genus Orconectes predominates within the Ozark

Highlands, Boston Mountains, and Ouachita Mountains.

These ecological sections also support about 10 percent

of the species and subspecies recognized in the entire

genus Cambarus, the second most diverse genus in the

family. Although several of the 13 representatives of the

genus Procambarus are primarily lowland in distribution, others are completely adapted to upland habitats

(e.g., Procambarus tenuis) or have penetrated the

region from adjacent prairie regions or lowlands

(Bouchard and Robison 1980, Pflieger 1996). Eight of

the nine representatives of the genus Cambarus in the

Table 2.17—Crayfishes of the Ozark-Ouachita Highlands

Species Common name Endemic

Cambarellus puer Cajun dwarf

Cambarellus shufeldtii Shufeldt’s dwarf

Cambarus aculabrum X

Cambarus causeyi X

Cambarus diogenes Devil crayfish

Cambarus hubbsi Hubb’s crayfish X

Cambarus hubrichti Salem Cave crayfish X

Cambarus maculatus Freckled crayfish X

Cambarus setosus Bristly Cave crayfish X

Cambarus tartarus X

Cambarus zophonastes X

Fallicambarus caesius X

Fallicambarus fodiens Digger crayfish

Fallicambarus harpi Harp’s crayfish X

Fallicambarus jeanae X

Fallicambarus strawni X

Faxonella blairi X

Faxonella clypeata Shield crayfish

Orconectes acares X

Orconectes eupunctus Coldwater crayfish X

Orconectes harrisonii Belted crayfish X

Orconectes hylas Woodland crayfish X

Orconectes immunis Papershell crayfish

Orconectes leptogonopodus X

Orconectes longidigitus Longpincered crayfish X

Orconectes luteus Golden crayfish

Orconectes macrus Neosho midget crayfish X

Orconectes marchandi Mammoth Spring crayfish X

Orconectes medius Saddlebacked crayfish X

Orconectes meeki brevis X

Orconectes meeki meeki Meek’s crayfish X

Orconectes menae X

Orconectes nais

Orconectes nana X

Orconectes neglectus X

chaenodactylus

Orconectes neglectus neglectus Ringed crayfish

Orconectes ozarkae Ozark crayfish X

Orconectes palmeri

Orconectes peruncus Big Creek crayfish X

Orconectes punctimanus Spothanded crayfish X

Orconectes quadruncus St. Francis River crayfish X

Orconectes saxatilis X

Orconectes virilis Northern crayfish

Orconectes williamsi William’s crayfish X

Procambarus acutus White River crayfish

Procambarus clarkii Red swamp crayfish

Procambarus curdi

Procambarus gracilis Grassland crayfish

Procambarus liberorum X

Procambarus ouachitae X

Procambarus parasimulans

Procambarus regalis X

Procambarus reimeri X

Procambarus simulans

Procambarus tenuis

Procambarus tulanei

Procambarus viaeviridis Vernal crayfish

Source: see “Data Sources and Methods of Analysis” of this section.

134
aquatic study area are endemics and are either cave

dwellers or are adapted to clear, spring-fed streams

(Robison and Allen 1995, Pflieger 1996). The aquatic

study area supports about 30 percent of all species

known in the genus Fallicambarus and represents a

significant center of diversity for this group of small,

primarily burrowing crayfishes.

Crayfish richness and density. The number of

crayfish species is not distributed evenly among the

hydrologic units. Species richness averaged 5.9 crayfish

species per hydrologic unit and ranged from 2 to 14

species (table 2.18). No crayfish were recorded as

present in the Dirty-Greenleaf unit because of insufficient data for Oklahoma. Most units, however, showed

diverse crayfish faunas; 29 of 50 units showed crayfish

richness greater than 4 species.

Three geographic areas had primary levels of

crayfish richness (8 to 14 species) (fig. 2.27): (1) the

southeastern part of the Ouachita Mountains, (2) the

central part of the Highlands in the Upper White River

Basin, and (3) the northeastern corner of the Ozark

Highlands. Hydrologic units of the southeastern

Ouachita Mountains showing primary levels of crayfish

richness included three of the four watersheds in the

Ouachita-Saline drainage and the Lower Little watershed of the Kiamichi-Little drainage. The second group

of hydrologic units with primary levels of crayfish

richness includes (from southwest to northeast): Beaver

Reservoir and Bull Shoals watersheds (Upper White

River drainage); Spring, Current, and Upper Black

watersheds (Upper Black River drainage); the Upper

St. Francis watershed; and the Big and Meramec

watersheds (Meramec River drainage). The highest

values of crayfish species richness are in the Upper

Black River drainage (Current watershed—14 crayfish

species; Upper Black watershed—12 species) and the

Kiamichi-Little River Basin (Lower Little watershed—

13 species) (table 2.18).

Secondary levels of crayfish species richness (6 to 7

species) generally follow geographic patterns of units

with primary levels of richness. For example, the Illinois,

Lower Neosho, and Elk watersheds (Neosho-Illinois

drainage); James unit (Upper White River drainage);

and Robert S. Kerr and Frog-Mulberry watersheds

(Arkansas River drainage) surround much of the central

area with primary levels of diversity. Similarly, the Little

Table 2.18—Crayfish species richness, species density, and

number of endemic species by watershed

River basin Watershed Species Species Endemic

Watershed name code (HUC) richness density species

 No./100 mi2

Osage River Basin

H.S. Truman Reservoir 10290105 4 0.3 0

Sac 10290106 4 0.2 1

Pomme de Terre 10290107 2 0.2 0

South Grand 10290108 2 0.1 0

Lake of the Ozarks 10290109 2 0.1 0

Niangua 10290110 3 0.3 1

Lower Osage 10290111 3 0.3 0

Gasconade River Basin

Upper Gasconade 10290201 4 0.2 2

Big Piney 10290202 3 0.4 2

Lower Gasconade 10290203 4 0.4 2

Meramec River Basin

Meramec 07140102 9 0.4 6

Bourbeuse 07140103 4 0.5 1

Big 07140104 8 0.8 5

Upper St. Francis River Basin

Upper St. Francis 08020202 10 0.8 6

Neosho-Illinois River Basin

Lake O’ the Cherokees 11070206 5 0.5 2

Spring 11070207 5 0.2 2

Elk 11070208 7 0.7 4

Lower Neosho 11070209 7 0.3 4

Illinois 11110103 6 0.4 4

Arkansas River Basin

Dirty-Greenleaf 11110102 0 0.0 0

Robert S. Kerr Reservoir 11110104 6 0.3 3

Poteau 11110105 5 0.3 2

Frog-Mulberry 11110201 6 0.5 4

Dardanelle Reservoir 11110202 5 0.3 3

Conway-Pt. Remove 11110203 5 0.4 1

Petit Jean 11110204 3 0.3 0

Cadron 11110205 3 0.4 0

Fourche La Fave 11110206 4 0.4 1

Lower Ark-Maumelle 11110207 4 0.4 0

Kiamichi-Little River Basin

Kiamichi 11140105 4 0.2 2

Upper Little 11140107 2 0.1 1

Mountain Fork 11140108 2 0.2 2

Lower Little 11140109 13 0.7 3

Ouachita-Saline River Basin

Ouachita Headwaters 08040101 8 0.5 5

Upper Ouachita 08040102 11 0.6 5

Little Missouri 08040103 10 0.5 6

Upper Saline 08040203 7 0.4 1

Upper White River Basin

Beaver Reservoir 11010001 11 0.4 7

James 11010002 7 0.5 5

Bull Shoals Lake 11010003 11 0.4 8

Middle White 11010004 7 0.5 5

Buffalo 11010005 3 0.2 2

North Fork White 11010006 6 0.3 4

Little Red 11010014 6 0.3 4

Upper Black River Basin

Upper Black 11010007 12 0.6 2

Current 11010008 14 0.5 4

Lower Black 11010009 3 0.4 1

Spring 11010010 11 0.9 8

Eleven Point 11010011 7 0.6 5

Strawberry 11010012 6 0.8 3

HUC = hydrologic unit code; mi2

 = square mile.

135
Figure 2.27—Levels of crayfish species richness by watershed.

Species richness

Primary

Secondary

Tertiary

Insufficient data

Oklahoma

Arkansas

Missouri

Red, Middle White, and North Fork White (Upper

White drainage), and the Strawberry and Eleven Point

watersheds (Upper Black River drainage) are associated with the northeastern group of watersheds with

primary levels of crayfish species richness.

Tertiary levels of crayfish species richness (fewer

than six species) are concentrated primarily in hydrologic units in the northwestern one third of the Assessment area. All hydrologic units in the Osage and

Gasconade River drainages show tertiary levels of

crayfish richness as do the Spring and Lake O’ the

Cherokees watersheds (Neosho-Illinois drainage).

Most watersheds in the Arkansas River and the

Kiamichi-Little drainages also showed tertiary levels of

crayfish richness.

The density of crayfish species is not distributed

evenly among the hydrologic units (fig. 2.28). Crayfish

density averaged 0.4 crayfish species per 100 mi2

 of a

hydrologic unit and ranged from 0.1 to 0.9 (table 2.18).

Seventeen of 50 hydrologic units had crayfish species

densities of at least 0.5 species per 100 mi2

.

Two concentrations of primary levels of crayfish

species density (0.5 to 0.9 species per 100 mi2

) are

apparent (fig. 2.28). One concentration lies in the

northeastern corner of the Assessment area and

consists of the Middle White watershed and most

136
Secondary levels of crayfish species density (all

those watersheds with 0.4 species per 100 mi2

) occurred in one notable concentration in the eastern

Arkansas River Basin. Other watersheds showing

secondary levels of crayfish density were scattered

among the Neosho-Illinois, Upper White, Meramec, and

Gasconade drainages (fig. 2.28). Most of these scattered watersheds were adjacent to watersheds showing

primary levels of crayfish density.

watersheds in the Upper Black River, Upper St.

Francis, and Meramec drainages. A second group

showing primary levels of crayfish species density

consists of most watersheds in the Ouachita-Saline

drainage and the Lower Little watershed (KiamichiLittle drainages). In addition, two watersheds in the

Neosho-Illinois drainage (Lake O’ the Cherokees and

Elk), and one each in the Upper White River drainage

(James) and Arkansas River drainage (Frog-Mulberry)

showed primary levels of crayfish density.

Figure 2.28—Levels of crayfish species density by watershed.

Species density

Oklahoma

Arkansas

Missouri

Primary

Secondary

Tertiary

Insufficient data

137
(Pflieger 1996), most are in one or few a hydrologic

units. Many are known from very limited areas within a

single hydrologic unit (e.g., Cambarus zophonastes,

Orconectes eupunctus); (Robison and Allen 1995,

Pflieger 1996). Within the crayfish genus Orconectes,

at least 19 species or subspecies are endemic to the

Assessment area, 14 of which are in the Ozark Plateaus

and Boston Mountains. Within the northern half of the

Assessment area, the Upper White and Upper Black

drainages support at least six endemic species of the

crayfish genus Orconectes; the Meramec and Upper

St. Francis Rivers support two each. The Ouachita

Mountains area supports five endemic crayfishes of the

genus Orconectes.

Nearly all members of the crayfish genus Cambarus

within the Assessment area are endemic species;

similar to the genus Orconectes, the highest number

occurred on the Ozark Highlands and Boston Mountains. Most of the narrowly distributed Cambarus

endemic species are highly adapted for life in caves or

springs and show very restricted distributions (Robison

and Allen 1995, Pflieger 1996). Five species are primarily cave dwellers or nearly so: Cambarus aculabrum,

an Ozark endemic; Cambarus hubrichti, a widespread

cave dweller of the Ozark Highlands; Cambarus

setosus, confined to three spring systems in the Salem

Plateau; Cambarus tartarus, known from one Oklahoma cave; and Cambarus zophonastes, a White

River Basin endemic (Bouchard and Robison 1980,

Hobbs 1989, Robison and Allen 1995, Pflieger 1996).

Of these, Cambarus aculabrum, C. tartarus, and

C. zophonastes are known only from one or two cave

systems each. Cambarus hubbsi and C. maculatus

(the latter a Meramec River endemic) are adapted to

life in streams (Robison and Allen 1995, Pflieger 1996).

Within the crayfish genera Fallicambarus, Faxonella,

and Procambarus, eight species are endemic to the

southern portion of the Ouachita Mountains (Robison

and Allen 1995).

Implications and Opportunities

Crayfishes are found in almost every type of aquatic

habitat, where they facilitate many important ecological

processes. However, compared to other aquatic

organisms such as fish and mussels, there is limited

Patterns of tertiary levels of crayfish density (0.1 to

0.3 species per 100 mi2

) were similar to patterns

observed for tertiary levels of crayfish species richness.

A distinct concentration of hydrologic units with tertiary

levels of crayfish species density occupies the northern

one-third of the Assessment area and includes watersheds of the Osage River; most watersheds in the

Gasconade River drainage; the Spring watershed

(Neosho-Illinois drainage), and the North Fork White

watershed (Upper White drainage). Likewise, several

watersheds in the Arkansas River drainage, Upper

White drainage, and those along the western edge of the

Assessment area show tertiary levels of crayfish

species density.

Endemic crayfishes. The Ozark-Ouachita Highlands support at least 37 endemic crayfishes (table

2.17), which represent about 61 percent of the crayfish

fauna known from the study area. Five of the six

crayfish genera (Orconectes, Cambarus,

Fallicambarus, Faxonella, and Procambarus) within

the Assessment area are represented by endemic

species. Most endemic species occur in waters of the

Ozark Plateaus and Boston Mountains (at least 22

endemic crayfishes), but endemicity is also relatively

high in the Ouachita Mountains (at least 13 endemic

crayfishes).

At least one endemic crayfish species is represented

in 41 of the 50 hydrologic units. Endemicity averaged

2.8 species per unit (two standard errors = 0.06) and

ranged from 0 to 8 (table 2.18). Primary levels of

endemicity (five to eight endemic crayfishes) were

concentrated in the Ozark Highlands in watersheds of

the Upper White, Upper Black, Upper St. Francis, and

Meramec River Basins. Hydrologic units in the

Ouachita-Saline drainage of the southeastern Ouachita

Mountains also showed primary levels of endemicity

(fig. 2.29). The number of endemic species was highest

(7 to 8 species) in the Upper White River Basin (Beaver Reservoir and Bull Shoals Lake watersheds and the

Upper Black River Basins’ Spring watershed. Secondary levels of endemicity (3 to 4 species) include 11

watersheds located primarily in the Boston Mountains

and southeastern Ozark Highlands (fig. 2.29).

Although a few endemic crayfishes enjoy a relatively

wide distribution across several hydrologic units of the

Ozark-Ouachita Highlands (e.g., Cambarus hubbsi);

138
knowledge about basic crayfish biology, distribution, and

ecological importance. The Aquatic Team synthesized

the known information on crayfishes and discovered

that there are distinct information voids.

Species richness, densities, and endemism were

unevenly distributed within the Assessment area. The

high numbers of endemic species (61 percent of the

crayfish in the Assessment area)—many with extremely limited range—suggest opportunities for

academic research. Incorporation of crayfish study and

monitoring into routine State and Federal management

and monitoring plans will provide valuable information

for stream quality and greatly augment knowledge of

this diverse resource. A lack of historical information

results in an even greater urgency to establish a

baseline of information to accurately examine crayfish

populations.

Figure 2.29—Levels of endemic crayfish species richness by watershed.

Endemic species richness

Primary

Secondary

Tertiary

Insufficient data or no endemics

Oklahoma

Arkansas

Missouri

139
Diversity of Aquatic Insects

Question 2.7: What are the status and

distribution of aquatic insects within the

Assessment area?

The Aquatic Team focused its assessment of aquatic

insects on two orders—the caddisflies (order

Trichoptera) and stoneflies (order Plecoptera)—because

comprehensive distributional monographs are available

on them for the Interior Highlands (Poulton and Stewart

1991, Moulton and Stewart 1996). Members of both

orders are used routinely in biological monitoring due to

their sensitivity to changes in water quality (Platts and

others 1983, Rohm and others 1987, Plafkin and others

1989, U.S. EPA 1989b, Clingenpeel and Cochran 1992).

The caddisfly fauna of the Assessment area is allied

most closely with counterparts in the Eastern (e.g.,

Appalachian Mountains) and Southeastern United

States. For example, the number of shared caddisfly

species in the Assessment area, the eastern Highlands

(Appalachians), and the southeastern Gulf Coastal Plain

is so high and the intermixing so thorough that clear

differences among the three regions’ caddisfly assemblages are difficult to distinguish (Hamilton and Morse

1990).

Caddisfly richness is lower in the Highlands than in

other mountainous areas of North America. According

to Ross (1965) and Rafferty (1985), this lower richness

may be due to (1) the size of the Highlands and (2) the

area being the most arid, low-level mountainous part of

North America. No known caddisfly lineages appear to

have originated in the Highlands. The relatively low

caddisfly richness indicates that the fauna is relatively

recent in its origin in the Highlands (Moulton and

Stewart 1996).

The mountainous topography, high-gradient streams,

varying levels of flow permanence (i.e., the influence of

storms and drought on streamflow seasonality), temperature regimes, and generally mild climate of the

Highlands account in large part for the unique stonefly

and caddisfly faunas of the Assessment area (Poulton

and Stewart 1991, Moulton and Stewart 1996). Three

patterns of primary species distribution describe the

observed richness of the stonefly and caddisfly faunas of

the Assessment area: (1) endemic species; (2) widespread species with continuous distributions or open

dispersal routes (i.e., regional populations can disperse

across the Illinois Ozarks corridor); and (3) species with

discontinuous distributions (i.e., regional populations that

are geographically separated from their main ranges)

(Poulton and Stewart 1991, Moulton and Stewart 1996).

 Key Findings

 1. Streams and rivers of the Ozark-Ouachita Highlands harbor a richness of species representing

about 15 percent and 17 percent of all stoneflies

and caddisflies, respectively, known from North

America. Eight families including 23 stonefly

genera and 82 species and 17 families including 57

caddisfly genera and 206 species are known to

occur in the Ozark-Ouachita Highlands Assessment area.

 2. The Ouachita Mountains support the greatest

richness of stoneflies and caddisflies (195 species)

in the Assessment area. Nineteen of the regionally

endemic stonefly species occur in the Ouachita

Mountains; six of these occur in no other subregion. Three of the 13 endemic caddisfly species

(Cheumatopsyche robisoni, Ochrotrichia

robisoni, and Ochrotrichia weddleae) found in

the Ouachita Mountains are not known elsewhere.

Data Sources and Methods of Analysis

To analyze distributions of stoneflies and caddisflies,

the Aquatic Team subdivided each of 10 major drainages within the Assessment area according to hydrologic units or watersheds. River basins and watersheds

are shown in figure 1.2. Fifty hydrologic units or

watersheds were recognized within the aquatic study

area. Half of these watersheds extend beyond the

Assessment area and contain portions of other ecological sections (e.g., the Mississippi Alluvial Basin).

Within a particular hydrologic unit, the team determined

the presence or absence of a stonefly or caddisfly

species as well as endemicity. This was done primarily

from maps and distributional tables in Poulton and

Stewart (1991) and Moulton and Stewart (1996),

respectively.

140
Poulton and Stewart (1991) and Moulton and Stewart

(1996) independently undertook analyses of faunal

composition of stoneflies and caddisflies. Both studies

used smaller drainage units and more finely divided

ecological regions than were used in this Assessment

report. Each study also included several variables to

classify or predict the presence of stonefly or caddisfly

species (e.g., stream size, flow permanence, and

vegetational types for stoneflies; and latitude, longitude,

physiography, geology, springs, and vegetational type for

caddisflies). A summary and synthesis of the primary

results of the two studies are presented here; for details,

the reader is referred to the original studies.

Poulton and Stewart (1991) collected specimens

from more than 1,200 sites. These researchers included

monthly collections of stoneflies from 693 stream sites

across 123 watersheds between November 1983 and

May 1988. They found stoneflies at 523 sites and

subsequently made repeat collections at 191 of these.

For caddisflies, Moulton and Stewart (1996) collected

from over 500 different locations between March 1990

and March 1994. Limited collecting occurred after

November 1992. These researchers augmented their

field collection records by examining and including

museum material. In both of these substantial and

unprecedented studies, most collection localities were

within the Assessment area.

The Aquatic Team used species richness, species

density, and number of regionally endemic species to

analyze diversity of stoneflies and caddisflies. Species

richness is the number of stoneflies and caddisflies

within each hydrologic unit. Hydrologic units vary in

size, and aquatic species richness often increases with

an increase in stream size or area drained (areal

additivity). To examine the effect of areal additivity, the

Aquatic Team divided species richness by the number

of square miles to produce species density values

(expressed as density per 100 mi2

) for each unit. In

addition, the team examined the regression of the log of

stonefly and caddisfly species richness with the log of

square miles in hydrologic units.

The Aquatic Team plotted species richness, species

density, and regional endemicity on separate hydrologic

unit maps of the Assessment area. The team recognized

three levels of relative species richness, density, and

endemicity among hydrologic units: primary, secondary,

and tertiary. Primary levels were assigned to the 15 to

17 units, depending on tied scores, with highest values;

secondary levels to the next highest 15 to 21 units; and

tertiary values to the remaining units. Hence, primary

levels approximate values in the fourth quartile (or top

25 percent); secondary levels, values in the third quartile

(or second 25 percent); and tertiary levels, values in the

first and second quartiles (or bottom 50 percent).

Patterns and Trends

Stonefly and caddisfly species composition.

Richness is divided unevenly among stoneflies and

caddisflies in the aquatic study area. For the stoneflies,

8 families, 23 genera, and 82 species are represented

(Poulton and Stewart 1991). Three stonefly families,

Perlidae (26 species), Capniidae (15 species), and

Perlodidae (14 species) represent 67 percent of the

stonefly fauna of the study area. Caddisflies are represented by 206 species distributed among 57 genera and

17 families. The families Hydroptilidae (59 species),

Leptoceridae (42 species), and Hydropsychidae (31

species) account for 64 percent of the study area’s

caddisfly fauna (Moulton and Stewart 1996).

Analyses of similarity of stonefly assemblages among

study area watersheds showed a primary split between

upland and lowland stonefly species similar to that

described for freshwater fishes (Pflieger 1971, 1975;

Mayden 1985; Matthews and Robison 1988; Poulton and

Stewart 1991; Moulton and Stewart 1996). Watersheds

with primarily lowland stonefly species included those

bordering the Assessment area in the Mississippi Alluvial

Basin, Missouri River border, and Illinois Ozarks.

Most of the Assessment area is dominated by upland

stonefly species, where distinct groupings of stoneflies

occur within the Assessment area. One faunal region

for stoneflies, which is at least in part analogous to the

Ozark Fish Faunal Region, includes most of the watersheds of the Ozark Plateaus, excluding the Black River

drainage. The Black River and several immediately

adjacent and connecting watersheds in the Gasconade

and Meramec Rivers have a distinctive assemblage of

stoneflies associated primarily with the presence of

high-volume springs. Watersheds in the Ouachita

Mountains, Arkansas Valley, and parts of the Boston

Mountains comprise another distinct grouping of

stoneflies—one that possesses the highest numbers of

endemic species (Poulton and Stewart 1991).

141
Although some species have strong affinities for

particular geographic areas, the presence or absence of

many uncommon species reflects historical (often

influenced by the glacial era) distributions as well as

ecological or geographic isolation. For example, 23

species were common in intermittent or dry streams,

and an additional 28 were restricted to permanently

flowing streams or spring-fed streams. Poulton and

Stewart (1991) concluded that the best predictors of

stonefly occurrence were stream thermal regime and

flow permanence—variables related strongly to lifecycle requirements of different stonefly species.

Caddisflies showed fewer distinct faunal groupings

than either stoneflies or fishes (Moulton and Stewart

1996). The Ozark Highlands are distinguished clearly as

a faunal region, but caddisfly assemblages do not vary

among the watersheds of the Mississippi Alluvial Plain,

West Gulf Coastal Plain, or most of the Ouachita

Mountains. Interwatershed dispersals of caddisflies tend

to minimize regional differences. Because of this

homogeneity of caddisfly assemblages among watersheds, physiographic subregion served as the best

predictor of the presence of endemic caddisflies

(Moulton and Stewart 1996).

Stonefly and caddisfly combined species richness and density. Numbers of stonefly and caddisfly

species were not evenly distributed among the watersheds (table 2.19), nor were their distributions oriented

to a simple geographical axis or direction. Combined

species richness averaged 66.4 species per watershed

and ranged from 9 to 123 species. Most watersheds,

however, showed diverse, rich faunas: 35 of the 50

hydrologic units showed stonefly and caddisfly species

richness of 50 or more species.

Three geographic centers of primary levels of

stonefly and caddisfly species richness (85 to 123

species) were apparent within the aquatic study area

(fig. 2.30): (1) a north central center in the Ozark

Highlands, (2) a western center in the Arkansas and

Neosho-Illinois River Basins, and (3) a southern center

in southward draining rivers of the Ouachita Mountains.

The northern center included the Upper and Lower

Gasconade watersheds in the Gasconade River Basin;

North Fork White, Middle White, and Bull Shoals

watersheds in the Upper White drainage; and the

Current watershed in the Upper Black River Basin. The

western center comprised watersheds within the

Neosho-Illinois drainage (Illinois watershed) and

Arkansas River drainage (Robert S. Kerr Reservoir,

Dardanelle Reservoir, Frog-Mulberry, and Poteau

watersheds). The southern center comprised watersheds in the Kiamichi-Little drainage (Kiamichi, Mountain Fork, and Lower Little watersheds) and the

Ouachita-Saline drainage (Little Missouri, Ouachita

Headwaters, and Upper Ouachita watersheds).

Secondary levels of stonefly and caddisfly species

richness (49 to 84 species) generally were located in the

northern two thirds of the Assessment area (fig. 2.30).

Most watersheds with secondary levels of species

richness (57 percent) occurred as tributaries to the

Neosho-Illinois (Spring and Elk watersheds), Upper

White (James, Beaver, Buffalo, Little Red watersheds),

and Upper Black River Basins (Spring, Eleven Point,

Strawberry, and Upper and Lower Black watersheds).

Other areas with secondary levels of species richness

are scattered throughout the Assessment area (fig. 2.30).

Stonefly and caddisfly combined species density was

highly variable among hydrologic units of the Assessment area (table 2.19). The average species density

was 4.7 species per 100 mi2

, and the range in density

was 0.6 to 10.4 species per 100 mi2

. Regression of the

log of stonefly and caddisfly species richness with the

log of square miles in units was significant (P < 0.0007).

However, the relationship accounted for only 18 percent

of the variation in species richness (where log species

richness = 1.98 + 0.193 log (unit area) and r2

 = 0.18).

The density of stonefly and caddisfly species was

correlated negatively with watershed area (r = -0.71,

P < 0.0001). This indicates that the smaller watersheds

tended to have greater species density.

Watersheds with primary density levels (5.6 to 10.4

stonefly and caddisfly species per 100 mi2

) were found

in four clusters, the western portion of the Arkansas

Valley, the Ouachita Mountains, and both the lower

eastern and the north central areas of the Ozark

Highlands (fig. 2.31). Of these watersheds, nine also

had primary and seven had secondary levels of species

richness. Watersheds in the species-rich Arkansas

River drainage (Frog-Mulberry and Robert S. Kerr

watersheds); Neosho-Illinois drainage (Illinois

watershed); Ouachita-Saline River drainage (Ouachita

Headwaters and Upper Ouachita watersheds); and

142
143

Table 2.19—Stoneflies (Plecoptera), caddisflies (Tricoptera), and combined species richness and density within

watersheds of the aquatic study area

Tricoptera and Tricoptera and

River basin Watershed code Tricoptera Plecoptera Plecoptera combined Plecoptera combined

Watershed name (HUC) Area species species species richness species density

100

 mi2

 - - - - - - - - - - - - - - - - Number - - - - - - - - - - - - - - - Number per 100 mi2

Osage River Basin

H.S. Truman Reservoir 10290105 12.1 4 13 17 1.4

Sac 10290106 19.7 48 24 72 3.6

Pomme de Terre 10290107 8.5 33 22 55 6.5

South Grand 10290108 20.6 4 9 13 0.6

Lake of the Ozarks 10290109 13.8 13 26 39 2.8

Niangua 10290110 10.4 54 27 81 7.8

Lower Osage 10290111 10.8 10 28 38 3.5

Gasconade River Basin

Upper Gasconade 10290201 17.9 83 30 113 6.3

Big Piney 10290202 7.5 15 19 34 4.5

Lower Gasconade 10290203 10.3 52 35 87 8.4

Meramec River Basin

Meramec 07140102 21.5 22 37 59 2.7

Bourbeuse 07140103 8.3 7 23 30 3.6

Big 07140104 9.7 11 22 33 3.4

Upper St. Francis River Basin

Upper St. Francis 08020202 13.0 28 36 64 4.9

Neosho-Illinois River Basin

Lake O’ the Cherokees 1107020146 9.2 6 11 17 1.9

Spring 11070207 25.7 34 28 62 2.4

Elk 11070208 10.4 35 28 63 6.1

Lower Neosho 11070209 22.1 6 21 27 1.2

Illinois 11110103 16.4 74 37 111 6.8

Arkansas River Basin

Dirty-Greenleaf 11110102 7.9 9 24 33 4.2

Robert S. Kerr Reservoir 11110104 18.1 57 46 103 5.7

Poteau 11110105 18.9 75 26 101 5.3

Frog-Mulberry 11110201 12.7 48 37 85 6.7

Dardanelle Reservoir 11110202 18.6 64 33 97 5.2

Conway- Pt. Remove 11110203 11.4 18 21 39 3.4

Petit Jean 11110204 10.9 2 31 33 3.0

Cadron 11110205 7.8 16 22 38 4.9

Fourche La Fave 11110206 11.2 32 42 74 6.6

Lower Ark-Maumelle 11110207 11.1 0 9 9 0.8

Kiamichi-Little River Basin

Kiamichi 11140105 18.2 75 24 99 5.4

Upper Little 11140107 14.0 29 20 49 3.5

Mountain Fork 11140108 8.6 66 24 90 10.4

Lower Little 11140109 19.7 66 38 104 5.3

Ouachita-Saline River Basin

Ouachita Headwaters 08040101 15.4 66 36 102 6.6

Upper Ouachita 08040102 17.7 79 35 114 6.5

Little Missouri 08040103 21.0 72 39 111 5.3

Upper Saline 08040203 17.1 23 31 54 3.1

Upper White River Basin

Beaver Reservoir 11010001 25.6 34 40 74 2.9

James 11010002 14.4 25 27 52 3.6

Bull Shoals Lake 11010003 26.0 59 37 96 3.7

(continued)
144

Figure 2.30—Levels of stonefly and caddisfly species richness (combined) by watershed.

Species richness

Primary

Secondary

Tertiary

Oklahoma

Arkansas

Missouri

Table 2.19—Stoneflies (Plecoptera), caddisflies (Tricoptera), and combined species richness and density within

watersheds of the aquatic study area (continued)

Tricoptera and Tricoptera and

River basin Watershed code Tricoptera Plecoptera Plecoptera combined Plecoptera combined

Watershed name (HUC) Area species species species richness species density

100

 mi2

 - - - - - - - - - - - - - - - - Number - - - - - - - - - - - - - - - Number per 100 mi2

Upper White River Basin (cont.)

 Middle White 11010004 15.0 65 36 101 6.7

Buffalo 11010005 13.4 29 35 64 4.8

North Fork White 11010006 18.3 59 28 87 4.8

Little Red 11010014 17.9 29 31 60 3.3

Upper Black River Basin

Upper Black 11010007 19.1 46 36 82 4.3

Current 11010008 26.3 85 38 123 4.7

Lower Black 11010009 7.8 27 32 59 7.6

Spring 11010010 12.2 34 34 68 5.6

Eleven Point 11010011 12.1 33 22 55 4.6

Strawberry 11010012 7.7 18 32 50 6.5

HUC = hydrologic unit code; mi2

 = square mile.
Gasconade River drainage (Upper and Lower Gasconade watersheds) also showed primary levels of stonefly

and caddisfly species density, as did the Mountain Fork

(Kiamichi-Little drainage) and Middle White (Upper

White River drainage) watersheds. The Spring, Strawberry, and Lower Black (Upper Black River drainage);

Fourche La Fave (Arkansas River drainage); Elk

(Neosho-Illinois drainage); and the Pomme de Terre

and Niangua (Osage River drainage) watersheds all

had primary levels of species density but secondary

levels of species richness.

Areas with secondary levels of species density (3.6

to 5.4 caddisfly and stonefly species per 100 mi2

)

traverse the study area from southwest to northeast (fig.

2.31). Fourteen of 18 watersheds showing secondary

levels of species density also had primary or secondary

levels of species richness. Seven hydrologic units within

the Upper White and Upper Black River drainages

showed secondary density levels (the James, Bull

Shoals, Buffalo, North Fork White, Eleven Point,

Current, and the Upper Black watersheds). All of these

watersheds also showed either primary or secondary

levels of species richness. Other watersheds that

showed secondary levels of density and either primary

or secondary levels of species richness included: the

Kiamichi and Lower Little (Kiamichi-Little drainage);

Dardenelle and Poteau (Arkansas River drainage);

Upper St. Francis drainage; Little Missouri (Ouachita

drainage); and the Sac (Osage drainage). Finally, four

watersheds showed secondary levels of species density

Figure 2.31—Levels of stonefly and caddisfly species density (combined) by watershed.

Species density

Primary

Secondary

Tertiary

Oklahoma

Arkansas

Missouri

145
and only tertiary levels of species richness: the

Bourbeuse (Meramec River drainage), Dirty Greenleaf

and Cadron (Arkansas River drainage), and Big Piney

(Gasconade drainage) watersheds. Watersheds with

primary or secondary levels of both species richness and

density may be considered exceptional areas of insect

diversity within the study area.

Endemic caddisflies and stoneflies. Fifty-one (16

percent) of the 316 stonefly and caddisfly species

represented in the Highlands are considered endemic

species, including 24 species (25 percent) of stoneflies

and 27 species (11 percent) of caddisflies (table 2.20).

Eleven of 17 caddisfly families have at least 1 endemic

species in the study area. The families Hydroptilidae,

Leptoceridae, and Glossosomatidae have seven, four,

and three endemic species, respectively, in the area.

The families Hydropsychidae and Lepidostomatidae

have two endemic species in the study area, and the

families Brachycentridae, Helicopsychidae,

Limnephilidae, Odontoceridae, Philopotamidae, and

Rhyacophilidae each have one (Moulton and Stewart

1996). Six of the eight stonefly families are represented

by multiple endemic species—eight from Perlidae,

seven from Capniidae, three from Leuctridae, two from

Taeniopterygidae, two from Chloroperlidae, and two

from Perlodidae (Poulton and Stewart 1991).

According to Poulton and Stewart (1991) and

Moulton and Stewart (1996), this estimate of the

number of endemic stonefly and caddisfly species is

conservative. Ongoing systematic studies of stoneflies

and caddisflies of the Assessment area indicate that

several currently recognized species may be two or

more distinct species or that further phylogenetic

analyses are needed (Moulton and Stewart 1996). For

example, the fieldwork of Poulton and Stewart (1991)

and Moulton and Stewart (1996) revealed four species

new to science and provided the first descriptions of the

immature stages of several species.

The number of endemic stonefly and caddisfly

species averaged 8.46 endemic species per watershed

and ranged from 0 to 22 species. Primary levels of

endemic species (11 to 22 species) were aggregated in

the Upper White and Upper Black (35 percent of the

primary level endemic watersheds); Arkansas (35

percent); Kiamichi-Little (15 percent); and OuachitaSaline (15 percent) drainages to form an almost contiguous grouping in the southern half of the study area (fig.

2.32). Twelve percent of the hydrologic units showed

primary levels of endemic species as well as primary

levels of species richness and density (Illinois, Robert S.

Kerr, Frog-Mulberry, Mountain Fork, Ouachita Headwaters, Upper Ouachita, and Middle White watersheds). All of the other watersheds with primary levels

of endemicity showed either primary or secondary

levels for species richness and density except for the

Beaver and Petit Jean watersheds, which had a tertiary

level of species density. The Current River watershed

had the highest endemicity (22 species) and species

richness (123 species) in the Highlands.

All watersheds with secondary levels of endemic

species (6 to 10 endemic species) occurred adjacent to

watersheds with primary levels of endemic species.

Nine (56 percent) of the 16 secondary-level watersheds

also had primary and/or secondary levels of species

richness and density. The Cadron watershed (Arkansas

River) showed a secondary level of endemic species,

but only a tertiary (one to five endemic species per

watershed) level of species richness and density.

Recently described, undescribed, and rare endemic

caddisfly species may occur in one or only a few hydrologic units. For example, Protoptila species A occurred

only in the Current River watershed; Neotrichia kitae,

only in the Bull Shoals watershed; Ceraclea

maccalmonti, only in Bennett Springs (Niangua watershed); and Marilia species A, only in the Spring River

and Upper Illinois watersheds. Glyphopsyche missouri,

although restricted to Meremec Spring, was a dominant

component of the benthic community. Agapetus artesus

was restricted to a few cold, high-volume Ozark springs

in Missouri, and Agapetus medicus occurred only in

perennial or ephemeral headwater streams in the Ozark

and Ouachita Mountains. Cheumatopsyche robisoni and

Cheumatopsyche rossi, two closely related endemic

species, were restricted primarily to free-flowing spring

habitats in the Ouachita Mountains and Ozark Highlands,

respectively. Ochrotrichia contorta was found only in

the high-volume spring habitat of the Eleven Point River

drainage; Ochrotrichia robisoni was restricted to small

to medium-sized streams in the Ouachita and Boston

Mountains physiographic regions; and Ochrotrichia

weddleae occurred only in second and third order

streams of the Kiamichi River (Moulton and Stewart

146
Table 2.20—Aquatic insects by order, family, and species found within the Assessment area

Ouachita Arkansas Boston Ozark

Order Family Species Mtns Valley Mtns Highlands

Plecoptera Capniidae Allocapnia granulata X XX X

Plecoptera Capniidae Allocapnia jeanaea X XX X

Plecoptera Capniidae Allocapnia malverna X X

Plecoptera Capniidae Allocapnia mohria X XX X

Plecoptera Capniidae Allocapnia mystica X X

Plecoptera Capniidae Allocapnia oribataa X

Plecoptera Capniidae Allocapnia ozarkanaa X X

Plecoptera Capniidae Allocapnia peltoidesa X X

Plecoptera Capniidae Allocapnia pygmaea X

Plecoptera Capniidae Allocapnia rickeri X XX X

Plecoptera Capniidae Allocapnia sandersonia XX X

Plecoptera Capniidae Allocapnia vivipara X

Plecoptera Capniidae Allocapnia warrenia X

Plecoptera Capniidae Nemocapnia carolina X

Plecoptera Capniidae Paracapnia angulata X XX

Plecoptera Chloroperlidae Alloperla caddoa X

Plecoptera Chloroperlidae Alloperla caudata X XX X

Plecoptera Chloroperlidae Alloperla hamata X XX

Plecoptera Chloroperlidae Alloperla leonarda X

Plecoptera Chloroperlidae Alloperla ouachitaa X

Plecoptera Chloroperlidae Haploperla brevis X XX X

Plecoptera Leuctridae Leuctra tenuis X XX

Plecoptera Leuctridae Zealeuctra cherokeea X XX X

Plecoptera Leuctridae Zealeuctra claasseni X XX X

Plecoptera Leuctridae Zealeuctra narfi X XX X

Plecoptera Leuctridae Zealeuctra wachitaa X

Plecoptera Leuctridae Zealeuctra warrenia X XX X

Plecoptera Nemouridae Amphinemura delosa X XX X

Plecoptera Nemouridae Amphinemura nigritta X

Plecoptera Nemouridae Prostoia completa X XX X

Plecoptera Nemouridae Prostoia similis X

Plecoptera Nemouridae Shipsa rotunda X

Plecoptera Perlidae Acroneuria evoluta X XX X

Plecoptera Perlidae Acroneuria filicis X XX X

Plecoptera Perlidae Acroneuria internata

Plecoptera Perlidae Acroneuria mela X XX X

Plecoptera Perlidae Acroneuria ozarkensisa X

Plecoptera Perlidae Acroneuria perplexa X XX X

Plecoptera Perlidae Agnetina capitata X

Plecoptera Perlidae Agnetina flavescens X XX X

Plecoptera Perlidae Attaneuria ruralis X

Plecoptera Perlidae Neoperla carlsoni X XX X

Plecoptera Perlidae Neoperla catharae X XX

Plecoptera Perlidae Neoperla choctaw XX X

Plecoptera Perlidae Neoperla falayaha X XX X

Plecoptera Perlidae Neoperla harpia X XX X

Plecoptera Perlidae Neoperla osagea X XX X

Plecoptera Perlidae Neoperla robisonia X XX

Plecoptera Perlidae Paragnetina kansensis X X

Plecoptera Perlidae Paragnetina media X

Plecoptera Perlidae Perlesta baumannia X X

Plecoptera Perlidae Perlesta brownia XX X

Plecoptera Perlidae Perlesta cinctipes X XX X

(continued)

147
Table 2.20—Aquatic insects by order, family, and species found within the Assessment area (continued)

Ouachita Arkansas Boston Ozark

Order Family Species Mtns Valley Mtns Highlands

Plecoptera Perlidae Perlesta decipiens X XX X

Plecoptera Perlidae Perlesta fuscaa X XX X

Plecoptera Perlidae Perlesta shubuta X

Plecoptera Perlidae Perlinella drymo X XX X

Plecoptera Perlidae Perlinella ephyre X XX X

Plecoptera Perlodidae Clioperla clio X XX X

Plecoptera Perlodidae Helopicus nalatus X XX X

Plecoptera Perlodidae Hydroperla crosbyi X XX X

Plecoptera Perlodidae Hydroperla fugitans X

Plecoptera Perlodidae Isoperla bilineata X

Plecoptera Perlodidae Isoperla burksi X XX X

Plecoptera Perlodidae Isoperla coushatta XX X

Plecoptera Perlodidae Isoperla decepta X

Plecoptera Perlodidae Isoperla dicala X X

Plecoptera Perlodidae Isoperla mohri X XX X

Plecoptera Perlodidae Isoperla namata X XX X

Plecoptera Perlodidae Isoperla ouachitaa X XX X

Plecoptera Perlodidae Isoperla signata X X

Plecoptera Perlodidae Isoperla szczytkoia X

Plecoptera Pteronarcyidae Pteronarcys pictetii X

Plecoptera Taeniopterygidae Strophopteryx arkansaea X XX X

Plecoptera Taeniopterygidae Strophopteryx cucullataa X XX X

Plecoptera Taeniopterygidae Strophopteryx fasciata X XX X

Plecoptera Taeniopterygidae Taeniopteryx burksi X XX X

Plecoptera Taeniopterygidae Taeniopteryx lita X X

Plecoptera Taeniopterygidae Taeniopteryx lonicera X

Plecoptera Taeniopterygidae Taeniopteryx maura X X

Plecoptera Taeniopterygidae Taeniopteryx metequi X XX X

Plecoptera Taeniopterygidae Taeniopteryx parvula X X

Trichoptera Brachycentridae Brachycentrus numerosus X

Trichoptera Brachycentridae Bracycentrus lateralis X

Trichoptera Brachycentridae Micrasema ozarkanaa X

Trichoptera Brachycentridae Micrasema rusticum X XX X

Trichoptera Brachycentridae Micrasema wataga X

Trichoptera Dipseudopsidae Phylocentropus placidus X X

Trichoptera Glossosomatidae Agapetus artesusa X

Trichoptera Glossosomatidae Agapetus illini X XX X

Trichoptera Glossosomatidae Agapetus medicusa X

Trichoptera Glossosomatidae Glossosoma intermedium X

Trichoptera Glossosomatidae Proptoptila species Aa X

Trichoptera Glossosomatidae Protoptila lega X X

Trichoptera Glossosomatidae Protoptila maculata X XX

Trichoptera Glossosomatidae Protoptila tenebrosa X

Trichoptera Helicopsychidae Helicopsyche borealis X XX X

Trichoptera Helicopsychidae Helicopsyche limnellaa X XX X

Trichoptera Helicopsychidae Helicopsyche piroa X X

Trichoptera Hydropsychidae Ceratopsyche bronta X X

Trichoptera Hydropsychidae Ceratopsyche morosa X X

Trichoptera Hydropsychidae Ceratopsyche piatrixa X X

Trichoptera Hydropsychidae Ceratopsyche slossonae X X

Trichoptera Hydropsychidae Cheumatopsyche aphanta X XX X

Trichoptera Hydropsychidae Cheumatopsyche burksi X XX X

Trichoptera Hydropsychidae Cheumatopsyche campyla X XX X

Trichoptera Hydropsychidae Cheumatopsyche gracilis X X

Trichoptera Hydropsychidae Cheumatopsyche harwoodi enigma X

(continued)

148
Table 2.20—Aquatic insects by order, family, and species found within the Assessment area (continued)

Ouachita Arkansas Boston Ozark

Order Family Species Mtns Valley Mtns Highlands

Trichoptera Hydropsychidae Cheumatopsyche lasia X X

Trichoptera Hydropsychidae Cheumatopsyche miniscula X XX X

Trichoptera Hydropsychidae Cheumatopsyche oxa X XX

Trichoptera Hydropsychidae Cheumatopsyche pasella X X

Trichoptera Hydropsychidae Cheumatopsyche pettiti X XX X

Trichoptera Hydropsychidae Cheumatopsyche robisonia X

Trichoptera Hydropsychidae Cheumatopsyche rossia XX X

Trichoptera Hydropsychidae Cheumatopsyche sordida X X

Trichoptera Hydropsychidae Cheumatopsyche speciosa X X

Trichoptera Hydropsychidae Diplectrona metaqui X

Trichoptera Hydropsychidae Diplectrona modesta X XX X

Trichoptera Hydropsychidae Homoplectra doringa XX X

Trichoptera Hydropsychidae Hydropsyche alvata X X

Trichoptera Hydropsychidae Hydropsyche arinale X XX X

Trichoptera Hydropsychidae Hydropsyche betteni X XX X

Trichoptera Hydropsychidae Hydropsyche bidens X X

Trichoptera Hydropsychidae Hydropsyche orris X XX X

Trichoptera Hydropsychidae Hydropsyche rossi X XX X

Trichoptera Hydropsychidae Hydropsyche scalaris X XX

Trichoptera Hydropsychidae Hydropsyche simulans X XX

Trichoptera Hydropsychidae Macrostemum carolina XX X

Trichoptera Hydropsychidae Potamyia flava X XX X

Trichoptera Hydroptilidae Dibusa angata X XX

Trichoptera Hydroptilidae Hydroptila ajax X

Trichoptera Hydroptilidae Hydroptila albicornis X

Trichoptera Hydroptilidae Hydroptila amoena X XX

Trichoptera Hydroptilidae Hydroptila angusta X X

Trichoptera Hydroptilidae Hydroptila armata X XX X

Trichoptera Hydroptilidae Hydroptila artesaa X

Trichoptera Hydroptilidae Hydroptila berneri X

Trichoptera Hydroptilidae Hydroptila broweri X

Trichoptera Hydroptilidae Hydroptila consimilis X X

Trichoptera Hydroptilidae Hydroptila delineata X

Trichoptera Hydroptilidae Hydroptila grandiosa X XX X

Trichoptera Hydroptilidae Hydroptila hamata X XX X

Trichoptera Hydroptilidae Hydroptila oneili X

Trichoptera Hydroptilidae Hydroptila perdita X XX X

Trichoptera Hydroptilidae Hydroptila quinola X X

Trichoptera Hydroptilidae Hydroptila remita X

Trichoptera Hydroptilidae Hydroptila sandersoni X XX X

Trichoptera Hydroptilidae Hydroptila spatulata X X

Trichoptera Hydroptilidae Hydroptila strepha X

Trichoptera Hydroptilidae Hydroptila tusculum X

Trichoptera Hydroptilidae Hydroptila vala XX X

Trichoptera Hydroptilidae Hydroptila virgata X XX X

Trichoptera Hydroptilidae Hydroptila waubesiana X XX X

Trichoptera Hydroptilidae Ithytrichia clavata X X

Trichoptera Hydroptilidae Ithytrichia mazon X

Trichoptera Hydroptilidae Leucotrichia pictipes X

Trichoptera Hydroptilidae Mayatrichia ayama X

Trichoptera Hydroptilidae Neotrichia arkansasensisa X XX X

Trichoptera Hydroptilidae Neotrichia kitaea X

Trichoptera Hydroptilidae Neotrichia minutisimella X

Trichoptera Hydroptilidae Neotrichia okopa XX X

Trichoptera Hydroptilidae Neotrichia riegeli X X

Trichoptera Hydroptilidae Neotrichia vibrans X XX

Trichoptera Hydroptilidae Ochrotrichia anisca X XX X

(continued)

149
Table 2.20—Aquatic insects by order, family, and species found within the Assessment area (continued)

Ouachita Arkansas Boston Ozark

Order Family Species Mtns Valley Mtns Highlands

Trichoptera Hydroptilidae Ochrotrichia arva X X

Trichoptera Hydroptilidae Ochrotrichia contortaa X

Trichoptera Hydroptilidae Ochrotrichia eliaga X

Trichoptera Hydroptilidae Ochrotrichia riesi X X

Trichoptera Hydroptilidae Ochrotrichia robisonia X X

Trichoptera Hydroptilidae Ochrotrichia spinosa X XX

Trichoptera Hydroptilidae Ochrotrichia tarsalis X XX

Trichoptera Hydroptilidae Ochrotrichia unio X

Trichoptera Hydroptilidae Ochrotrichia weddleaea X

Trichoptera Hydroptilidae Ochrotrichia xena X

Trichoptera Hydroptilidae Orthotrichia aegerfasciella X XX X

Trichoptera Hydroptilidae Orthotrichia cristata X

Trichoptera Hydroptilidae Orthotrichia instabilis X

Trichoptera Hydroptilidae Oxyethira coercens X X

Trichoptera Hydroptilidae Oxyethira dualis X X

Trichoptera Hydroptilidae Oxyethira forcipata X

Trichoptera Hydroptilidae Oxyethira janella X

Trichoptera Hydroptilidae Oxyethira novasota X X

Trichoptera Hydroptilidae Oxyethira pallida X XX X

Trichoptera Hydroptilidae Oxyethira rivicola X X

Trichoptera Hydroptilidae Oxyethira zeronia XX X

Trichoptera Hydroptilidae Paucicalcaria ozarkensisa X X

Trichoptera Hydroptilidae Stactobiella delira X XX

Trichoptera Hydroptilidae Stactobiella palmata XX X

Trichoptera Lepidostomatidae Lepidostoma carrolli X

Trichoptera Lepidostomatidae Lepidostoma griseum X X

Trichoptera Lepidostomatidae Lepidostoma leschenia X X

Trichoptera Lepidostomatidae Lepidostoma libum X X

Trichoptera Lepidostomatidae Lepidostoma ozarkensea X X

Trichoptera Lepidostomatidae Lepidostoma togatum XX X

Trichoptera Leptoceridae Ceraclea ancylus X XX X

Trichoptera Leptoceridae Ceraclea cancellata X XX X

Trichoptera Leptoceridae Ceraclea flava X XX X

Trichoptera Leptoceridae Ceraclea maccalmontia X

Trichoptera Leptoceridae Ceraclea maculata X XX X

Trichoptera Leptoceridae Ceraclea nepha X XX X

Trichoptera Leptoceridae Ceraclea ophioderus X X

Trichoptera Leptoceridae Ceraclea protonepha X XX X

Trichoptera Leptoceridae Ceraclea punctata X XX X

Trichoptera Leptoceridae Ceraclea resurgens X

Trichoptera Leptoceridae Ceraclea tarsipunctata X XX X

Trichoptera Leptoceridae Ceraclea transversa X XX X

Trichoptera Leptoceridae Leptocerus americanus XX X

Trichoptera Leptoceridae Mystacides sepulchralis X XX

Trichoptera Leptoceridae Nectopsyche candida X XX X

Trichoptera Leptoceridae Nectopsyche diarina X

Trichoptera Leptoceridae Nectopsyche exquisita X XX X

Trichoptera Leptoceridae Nectopsyche pavida X XX X

Trichoptera Leptoceridae Nectopsyche spiloma X X

Trichoptera Leptoceridae Oecetis avara X XX X

Trichoptera Leptoceridae Oecetis cinerascens XX X

Trichoptera Leptoceridae Oecetis ditissa X XX X

Trichoptera Leptoceridae Oecetis eddlestoni X XX

Trichoptera Leptoceridae Oecetis inconspicua X XX X

Trichoptera Leptoceridae Oecetis nocturna X XX X

Trichoptera Leptoceridae Oecetis osteni X

(continued)

150
Table 2.20—Aquatic insects by order, family, and species found within the Assessment area (continued)

Ouachita Arkansas Boston Ozark

Order Family Species Mtns Valley Mtns Highlands

Trichoptera Leptoceridae Oecetis ouachitaa X

Trichoptera Leptoceridae Oecetis ozarkensisa X

Trichoptera Leptoceridae Oecetis persimilis X XX X

Trichoptera Leptoceridae Setodes oxapiusa X X

Trichoptera Leptoceridae Triaenodes aba X

Trichoptera Leptoceridae Triaenodes cumberlandensis X

Trichoptera Leptoceridae Triaenodes dipsius X XX X

Trichoptera Leptoceridae Triaenodes flavescens X

Trichoptera Leptoceridae Triaenodes ignitus XX X

Trichoptera Leptoceridae Triaenodes injustus XX X

Trichoptera Leptoceridae Triaenodes marginatus X XX X

Trichoptera Leptoceridae Triaenodes melacus X

Trichoptera Leptoceridae Triaenodes nox X

Trichoptera Leptoceridae Triaenodes perna X X

Trichoptera Leptoceridae Triaenodes tardus XX X

Trichoptera Leptoceridae Triaenodes tridontus X

Trichoptera Limnephilidae Frenesia missa X

Trichoptera Limnephilidae Glyphopsyche missouria X

Trichoptera Limnephilidae Ironoquia punctatissima X XX X

Trichoptera Limnephilidae Limnephilus submonilifer X X

Trichoptera Limnephilidae Platycentropus radiatus X

Trichoptera Limnephilidae Pseudostenophylax uniformis X

Trichoptera Limnephilidae Pycnopsyche guttifer X

Trichoptera Limnephilidae Pycnopsyche indiana XX X

Trichoptera Limnephilidae Pycnopsyche lepida X XX X

Trichoptera Limnephilidae Pycnopsyche rossi X XX

Trichoptera Limnephilidae Pycnopsyche subfasciata X XX X

Trichoptera Molannidae Molanna blenda X XX

Trichoptera Molannidae Molanna ulmerina X XX

Trichoptera Molannidae Molanna uniophila X XX

Trichoptera Odontoceridae Marilia flexuosa X X

Trichoptera Odontoceridae Marilia species Aa X

Trichoptera Philopotamidae Chimarra aterrima XX X

Trichoptera Philopotamidae Chimarra feria X XX X

Trichoptera Philopotamidae Chimarra obscura X XX X

Trichoptera Philopotamidae Chimarra parasocia X X

Trichoptera Philopotamidae Chimarra socia X X

Trichoptera Philopotamidae Wormaldia moesta X XX X

Trichoptera Philopotamidae Wormaldia shawnee X

Trichoptera Philopotamidae Wormaldia strotaa X XX X

Trichoptera Phryganeidae Agrypnia vestita XX X

Trichoptera Phryganeidae Phryganea sayi X

Trichoptera Phryganeidae Ptilostomis ocellifera X XX X

Trichoptera Phryganeidae Ptilostomis postica XX X

Trichoptera Polycentropodidae Cernotina calcea X XX X

Trichoptera Polycentropodidae Cernotina spicata X

Trichoptera Polycentropodidae Cyrnellus fraternus X XX X

Trichoptera Polycentropodidae Neureclipsis crepuscularis X XX X

Trichoptera Polycentropodidae Paranyctiophylax affinis X XX X

Trichoptera Polycentropodidae Paranyctiophylax serratus XX X

Trichoptera Polycentropodidae Polycentropus centralis X XX X

Trichoptera Polycentropodidae Polycentropus chelatus X

Trichoptera Polycentropodidae Polycentropus cinereus X XX X

Trichoptera Polycentropodidae Polycentropus confusus X

Trichoptera Polycentropodidae Polycentropus crassicornis X XX X

Trichoptera Polycentropodidae Polycentropus harpi X XX X

(continued)

151
Figure 2.32—Levels of endemic stonefly and caddisfly species richness (combined) by watershed.

Endemic species richness

Primary

Secondary

Tertiary

Oklahoma

Arkansas

Missouri

Table 2.20—Aquatic insects by order, family, and species found within the Assessment area (continued)

Ouachita Arkansas Boston Ozark

Order Family Species Mtns Valley Mtns Highlands

Trichoptera Polycentropodidae Polycentropus stephania X X

Trichoptera Psychomyiidae Lype diversa XX X

Trichoptera Psychomyiidae Paduniella nearcticaa XX X

Trichoptera Psychomyiidae Psychomyia flavida X XX X

Trichoptera Rhyacophilidae Rhyacophila banksi X

Trichoptera Rhyacophilidae Rhyacophila fenestra X

Trichoptera Rhyacophilidae Rhyacophila glaberrima X X

Trichoptera Rhyacophilidae Rhyacophila kiamichia X XX X

Trichoptera Rhyacophilidae Rhyacophila lobifera X X

Trichoptera Uenoidae Neophylax concinnus X XX

Trichoptera Uenoidae Neophylax fuscus X

a Endemic species.

Source: Poulton and Stewart (1991), Moulton and Stewart (1996).

152
1996). Lepidostoma lescheni originally was found only

on Magazine Mountain (Petit Jean watershed) but has

since been collected in seeps and springs in the Little

Missouri watershed. Other endemic caddisflies were

locally abundant or evenly distributed throughout the

Highlands: Wormaldia strota (occurred in 20 percent of

the hydrologic units), Setodes oxapius (16 percent),

Neotrichia arkansasensis (16 percent), Helicopsyche

limnella (16 percent), Rhyacophila kiamichi (15

percent), and the newly described Paduniella nearctica

(8 percent).

Recently described endemic stonefly species also

have been found in one or only a few of the hydrologic

units. Isoperla szczytkoi occurred only in the Petit Jean

watershed; Alloperla caddo only in the Upper Saline

and Fourche La Fave watersheds; Alloperia ouachita

only in small, clear, rapid rocky streams in the Little

Missouri watershed; Acroneuria ozarkensis only in the

Buffalo and Lower Gasconade watersheds; Zealeuctra

wachita only in intermittent streams in the Upper

Ouachita watershed; Allocapnia oribata only in

perennial streams in the Little Red watershed; and

Allocapnia warreni only in the Illinois watershed

(Poulton and Stewart 1991). Endemic stonefly species

that occurred more abundantly and/or were more evenly

distributed within the Highlands were Isoperla

ouachita (occurs in 100 percent of the watersheds);

Allocapnia mohri (80 percent); Neoperla harpi (77

percent); Neoperla osage (75 percent); Strophopteryx

cucullata (56 percent); Strophopteryx arkansae (44

percent); Zealeuctra warreni (34 percent); and

Neoperla falayah (34 percent).

Implications and Opportunities

The levels of species richness, density, and numbers

of endemic stoneflies and caddisflies in the study area,

particularly the Ozark Highlands and Ouachita Mountains, indicate that habitat diversity for these aquatic

insects is high. Typical of mountainous areas, the

Highlands have extensive headwater streams, seeps,

and springs. These aquatic habitats are particularly rich

in aquatic insects and, in turn, are sensitive to detrimental effects from human activities.

The Aquatic Team examined and compared the

population distributions, species richness, species

density, and endemic distributions of Plecoptera and

Trichoptera, but much more could be added to achieve

as accurate a picture as possible. While studies by

Poulton and Stewart (1991) and Moulton and Stewart

(1996) offer unprecedented documentation of stoneflies

and caddisflies in the Assessment area, these insects

represent only a small part of the total aquatic invertebrate community. Plecoptera and Trichoptera are only 2

of the 12 aquatic insect orders listed in Merritt and

Cummins (1996). A more comprehensive list of aquatic

insects and other aquatic invertebrates would help

natural resource managers to better understand, monitor,

and support the health of aquatic systems.

Endangered, Threatened, and Other Aquatic

Species of Special Concern

Question 2.8: What are the status and

distribution of endangered, threatened, and other

aquatic species of special concern within the

Assessment area?

As is true elsewhere, conservation of aquatic

biodiversity in the Assessment area is a battle against

extinction (Minckley and Deacon 1991) and ultimately, a

battle for ecological integrity at landscape scales

(Angermeier and Karr 1994). The loss of and decline in

populations of aquatic species are attributed primarily to

alteration of habitats, chemical pollution, overexploitation, and/or the introduction of competitive

nonindigenous organisms (Allan and Flecker 1993,

Williams and others 1993, Warren and Burr 1994). The

process of extinction often can be related to landscapescale phenomena that decrease habitat area or quality

and increase isolation of populations (Angermeier 1995).

However, loss of diversity via extinction is not usually

observable or cataclysmic. Rather, the process is

gradual, with total extinction preceded by local or

regional annihilations (Angermeier 1995). Understanding

(and ultimately preventing) human-caused imperilment

and extinction of aquatic organisms is likely to require

far greater focus on landscape-level patterns and

processes than traditional approaches to maintaining

diverse aquatic communities have used in the past.

One of the most important lines of defense against

extinction of aquatic and other organisms in the United

153
154

States is the Endangered Species Act (ESA) of 1973, as

amended. However, the Clean Water Act (CWA) of

1972, as amended, is another potentially powerful

statutory vanguard for habitat and species conservation

that can prevent human-caused endangerment of

aquatic species and communities (Angermeier and Karr

1994). The ESA established a process whereby Federal

legal protections are available to protect animal and

plant species in jeopardy of extinction. Under the ESA,

the term “species” includes species, subspecies, and

certain distinctive populations (Littell 1992). Endangered, threatened, proposed endangered, and proposed

threatened animals and plants are provided protection

under the ESA and are listed under these categories by

the USDI Fish and Wildlife Service (1997a, b). Candidate species are those for which the Fish and Wildlife

Service has sufficient information to initiate listing under

the ESA (USDI FWS 1997a, b).

Other organizations and agencies, both public and

private, are playing increasing roles in the early recognition and long-term monitoring of species that are

potentially at risk of extinction or population declines.

Using protocols developed by The Nature Conservancy,

the States in the Assessment area track the distributions

and populations of species with Federal ESA status.

States also monitor those that are considered globally

imperiled through globally rare (i.e., ranked as G1, G2,

or G3 by The Nature Conservancy), and those with

State distributions (S1 through S5 as ranked by State

heritage programs). For a complete explanation of these

ranks, see the “Glossary of Terms” at the end of this

report.

In addition, the American Fisheries Society, using

panels of professional biologists, has provided independent rankings of conservation status for fishes (Williams

and others 1989b), mussels (Williams and others 1993),

and crayfishes (Taylor and others 1996). In this report,

the Aquatic Team discusses species recognized by State

heritage programs and the American Fisheries Society

as “of special concern” species. The information

provided by these groups can serve as a primary source

from which future candidates for Federal status may be

drawn (USDI FWS 1996) and as important planning and

prioritizing tools for recovery efforts, status surveys, and

research on aquatic organisms.

 Key Findings

 1. A total of 125 aquatic taxa have 1 or more of the

following designations: Federal status (14 species),

globally imperiled through globally rare (78 taxa

have G1, G2, or G3 ranks), and State critically

imperiled (68 taxa have S1 ranks). Included are 7

insects; 37 mollusks, 35 of which are freshwater

mussels; 23 crustaceans, 15 of which are crayfish;

55 fishes; and 3 herptiles (amphibians or reptiles).

 2. Of the 14 aquatic taxa with Federal status, 6 are

mollusks, 2 are crustaceans, and 6 are fishes.

 3. In the Assessment area, about 32, 50, and 26

percent of fishes, mussels, and crayfishes, respectively, have Federal status, globally rare ranks, and/

or S1 State ranks.

 4. Sixty percent of the hydrologic units recorded at

least one species with a Federal status on Element

Occurrence Records (EOR’s); the pattern of

distribution (i.e., 0 to 4 species per unit out of 14

possible species) suggests that the presence of

such species differs dramatically across units.

 5. Hydrologic units with three or four species with

Federal status were located in the southern

Ouachita Mountains (Upper Little, Lower Little,

and Upper Ouachita units), in the Neosho-Illinois

drainage (Lake O’ the Cherokees, Illinois, Elk, and

Spring units), and in the Sac unit (Osage River

drainage). Units with one to two species with

Federal status were scattered widely across the

Assessment area.

 6. Two concentrations of hydrologic units showed

primary levels of endangered, threatened, and other

species of special concern (10 to 30 species with

Federal status, global ranks, or State ranks): (1)

along the southern edge of the Assessment area in

the Ouachita Mountains and (2) along the northeastern edge of the Assessment area in the Upper

Black River and Upper St. Francis drainages.

Secondary levels of endangered, threatened, and

other species of special concern (seven to nine

species per watershed) tended to be associated

with hydrologic units adjacent to those with primary

levels.
Data Sources and Methods of Analysis

The Aquatic Team synthesized information on

endangered, threatened, and other aquatic organisms of

special concern, including aquatic insects, mollusks,

crayfishes, totally aquatic herptiles, and fishes. To

analyze and display the distribution of these aquatic

species, each of 10 major drainages within the aquatic

study area was subdivided, yielding 50 hydrologic units

or watersheds (fig. 2.17).

The team noted each endangered, threatened, and

other species of special concern that was present or

absent within each hydrologic unit. Some species with

occurrences in portions of hydrologic units extending

outside the Assessment area were included in the

analysis. The team included species with Federal status

(i.e., endangered, proposed endangered, threatened, and

proposed threatened under the ESA); those ranked

globally as G1, G2, or G3 by The Nature Conservancy;

and those ranked as S1, S2, or S3 by the State heritage

programs. The team referred to these three conservation rankings as “Federal status,” “global ranks,” and

“State ranks,” respectively. The team presented separately the conservation status rankings of the American

Fisheries Society (see the “Management Indicator

Species” section later in this chapter).

The team determined distributions of endangered,

threatened, and other aquatic species of special concern

within a particular hydrologic unit from Element Occurrence Records (EOR’s) received from heritage programs in Arkansas, Oklahoma, and Missouri (USDA FS

1997a, b). The EOR data sets were based on information updated by the States in 1997.

The team used the temporal coverage, spatial

coverage, and quality of information on State EOR’s to

determine the occurrence of each species within

hydrologic units. The presence of an endangered,

threatened, or other aquatic species of special concern

reflects known historical presence within a unit but does

not necessarily indicate the continued occurrence of a

species in that watershed. Recent verification of the

continued presence of species documented in historical

EOR’s (i.e., those 10 or 20 years old) may be limited by

constraints on funding, personnel, and expertise in State

heritage programs. Further, the collection of EOR data

tends to be weighted toward surveys or environmental

assessments associated with State or Federally regulated projects or lands. The team compared lists of

species compiled from EOR data with lists of endangered, threatened, proposed endangered, and proposed

threatened species of the USDI Fish and Wildlife

Service (1997a, b), and corrected inconsistencies. They

also augmented and corrected information from the

States by using information for fishes from Pflieger

(1975) and Robison and Buchanan (1988) and for

crayfishes from Pflieger (1996).

The Aquatic Team analyzed endangered, threatened,

and other aquatic organisms of special concern by major

groups of organisms (insects, mollusks, crustaceans,

fishes, and herptiles) and by geographic distribution. The

number of endangered and threatened species accounted

for by EOR’s was tallied for each hydrologic unit, and

the results were mapped across hydrologic units in four

categories: no Federal status species or insufficient data;

one to two Federal status species; three Federal status

species; and four Federal status species. The Aquatic

Team added the number of other species of special

concern (i.e., those with global and State ranks) to the

Federal status tally for each hydrologic unit and mapped

the results to show total imperilment for each unit. Three

levels of total imperilment were recognized among

hydrologic units: primary, secondary, and tertiary. Primary levels were assigned to the 13 units with highest

values, secondary levels to the next highest 14 units, and

tertiary values to the remaining units. Hence, primary

levels approximate values in the fourth quartile (top 25

percent), secondary levels (second 25 percent), values in

the third quartile, and tertiary levels, values in the first

and second quartiles (bottom 50 percent).

Patterns and Trends

Composition of Federal status and other aquatic

species of special concern. Representation of endangered, threatened, and other species of special concern

was uneven across major groups of aquatic organisms

(i.e., fish, mollusks, crayfishes, insects, and herptiles)

within the Assessment area. The 125 taxa included 7

insects, 37 mollusks (35 of which are freshwater

mussels), 23 crustaceans (15 of which are crayfish), 55

fishes, and 3 herptiles (table 2.21). Fourteen (including

two candidate species) of these have Federal status (six

155
Table 2.21—Endangered, threatened, and other species of special concern in the aquatic study area

Group Species Common name Globala Federalb MOc ARc OKc

Insect Allocapnia jeanae Winter stonefly G1? S1?

Insect Allocapnia ozarkana Winter stonefly G1? S1?

Insect Dannella provonshai Mayfly G1?

Insect Glyphopsyche missouri Missouri glyphopsyche caddisfly G1G3 S1S3

Insect Gomphus ozarkensis Ozark clubtail dragonfly G4 S2

Insect Ophiogomphus westfalli Arkansas snaketail dragonfly G2 S?

Insect Paduniella nearctica Nearctic paduniellan caddisfly G1? S1?

Mollusk Alasmidonta marginata Elktoe G5 S1

Mollusk Amnicola cora Foushee cavesnail G1 S1

Mollusk Anodonta grandis corpulenta Giant floater G5T3Q S2

Mollusk Anodonta suborbiculata Flat floater G4 S1?

Mollusk Antrobia culveri Tumbling creek cave snail G1 C S1

Mollusk Arcidens confragosus Rock pocketbook G3 S1

Mollusk Arkansia wheeleri Ouachita rock pocketbook G1 E S1 S1

Mollusk Cumberlandia monodonta Spectaclecase G2G3 S2

Mollusk Cyprogenia aberti Western fanshell G2 S1 S2

Mollusk Ellipsaria lineolata Butterfly G4 S2

Mollusk Elliptio dilatata Spike G5 S1

Mollusk Epioblasma curtisi Curtis pearlymussel G1T1 E S1 S1?

Mollusk Epioblasma triquetra Snuffbox G3 S1 S1

Mollusk Fusconaia ebena Ebonyshell G4 S1

Mollusk Glebula rotundata Round pearlshell G3G4 S1

Mollusk Lampsilis abrupta Pink mucket G2 E S2 S2

Mollusk Lampsilis hydiana Louisiana fatmucket G2 S1

Mollusk Lampsilis ornata Southern pocketbook G5 S1?

Mollusk Lampsilis powellii Arkansas fatmucket G1G2 T S2?

Mollusk Lampsilis rafinesqueana Neosho mucket G2 S1 S1 S1

Mollusk Lampsilis streckeri Speckled pocketbook G1Q E S1

Mollusk Lasmigona costata Fluted shell G5 S1

Mollusk Leptodea leptodon Scaleshell G2G3 S1 S? S1

Mollusk Ligumia recta Black sandshell G5 S1

Mollusk Obovaria jacksoniana Southern hickorynut G1G2 S2

Mollusk Plectomerus dombeyanus Bankclimber G4 S2

Mollusk Plethobasus cyphyus Sheepnose G3 S2

Mollusk Pleurobema cordatum Ohio River pigtoe G3 S2

Mollusk Ptychobranchus occidentalis Ouachita kidneyshell G3G4 S? S2

Mollusk Quadrula cylindrica Rabbitsfoot G4T2T3 S1 S? S1

Mollusk Quadrula metanevra Monkeyface G3 S1

Mollusk Simpsonaias ambigua Salamander mussel G2 S1?

Mollusk Toxolasma lividus Purple lilliput G1G2Q S1

Mollusk Toxolasma texasensis Texas lilliput G4 S1

Mollusk Villosa arkansasensis Ouachita creekshell G2 S1S2

Mollusk Villosa iris Rainbow G4 S1

Mollusk Villosa lienosa Little spectacle case G5 S2

Crustacean Allocrangonyx hubrichti Central Missouri cave amphipod G1G3 S1S3

Crustacean Caecidotea dimorpha Isopod G1 S3

Crustacean Caecidotea macropoda Bat cave isopod G1G3 SU

Crustacean Caecidotea steevesi Isopod G1 S1

Crustacean Caecidotea stiladactyla Isopod G1 S1

Crustacean Cambarus aculabrum Crayfish G1 E S?

Crustacean Cambarus causeyi Crayfish G1 S1

Crustacean Cambarus hubrichti Salem Cave crayfish G3 S2

Crustacean Cambarus setosus Bristly Cave crayfish G2 S2

Crustacean Cambarus zophonastes Cave crayfish G1 E S1

Crustacean Fallicambarus harpi Harp’s crayfish G1 S1

Crustacean Fallicambarus jeanae Crayfish G1 S?

Crustacean Fallicambarus strawni Crayfish G1G2 S1?

Crustacean Faxonella blairi Crayfish G2 S1S2

Crustacean Orconectes eupunctus Coldwater crayfish G3 S3

(continued)

156
Table 2.21—Endangered, threatened, and other species of special concern in the aquatic study area (continued)

Group Species Common name Globala Federalb MOc ARc OKc

Crustacean Orconectes marchandi Mammoth Spring crayfish G3 S3

Crustacean Orconectes peruncus Big Creek crayfish G2 S3

Crustacean Orconectes williamsi Williams’ crayfish G1 S?

Crustacean Procambarus parasimulans Crayfish G3 S?

Crustacean Procambarus reimeri Crayfish G3 S1?

Crustacean Stygobromus montanus Mountain cave amphipod G1 S1

Crustacean Stygobromus onondagaensis Onondaga cave amphipod G1G3 S1S3

Crustacean Stygobromus ozarkensis Ozark cave amphipod G? S1 S1

Fish Acipenser fulvescens Lake sturgeon G3 S1

Fish Amblyopsis rosae Ozark cavefish G2 T S1 S1 S1

Fish Ammocrypta clara Western sand darter G3G4 S2? S3

Fish Ammocrypta vivax Scaly sand darter G5 S1S2

Fish Atractosteus spatula Alligator gar G5 S2 S1

Fish Crystallaria asprella Crystal darter G3 S1 S2?

Fish Cycleptus elongatus Blue sucker G3 S3

Fish Cyprinella spiloptera Spotfin shiner G5 S1

Fish Esox niger Chain pickerel G5 S1SX

Fish Etheostoma fragi Strawberry (River) darter G5T1 S1

(E. spectabile fragi)

Fish Etheostoma cragini Arkansas darter G3GT C S2 S1 S2

Fish Etheostoma fusiforme Swamp darter G5 S2

Fish Etheostoma microperca Least darter G5 S1

Fish Etheostoma moorei Yellowcheek darter G1 S1

Fish Etheostoma nianguae Niangua darter G2 T S2

Fish Etheostoma pallididorsum Paleback darter G2 S2

Fish Etheostoma parvipinne Goldstripe darter G4G5 S2

Fish Fundulus blairae Blair’s starhead topminnow G3G4Q S2

Fish Fundulus sciadicus Plains topminnow G4 S1

Fish Hiodon alosoides Goldeye G5 S2

Fish Ictalurus nebulosus Brown bullhead G5 S1SH

Fish Lampetra aepyptera Least brook lamprey G5 S2?

Fish Lampetra appendix American brook lamprey G5 S2?

Fish Lythrurus snelsoni Ouachita Mountain shiner G2 S? S2

Fish Macrhybopsis aestivalis Arkansas River speckled chub G5T5 S?

tetranemus

Fish Moxostoma anisurum Silver redhorse G5 S1?

Fish Moxostoma macrolepidotum Shorthead redhorse G5 S2?

Fish Mugil cephalus Striped mullet G5 S1?

Fish Nocomis asper Redspot chub G4 S2?

Fish Notropis amnis Pallid shiner G4 S1S2

Fish Notropis atrocaudalis Blackspot shiner G4 S1

Fish Notropis bairdi Red River shiner G3 S3

Fish Notropis chalybaeus Ironcolor shiner G5 S1

Fish Notropis girardi Arkansas River shiner G2G3 P E SX S1

Fish Notropis hubbsi Bluehead shiner G3 S3 S1

Fish Notropis maculatus Taillight shiner G5 S1

Fish Notropis ortenburgeri Kiamichi shiner G3 S2 S3

Fish Notropis ozarcanus Ozark shiner G3 S3

Fish Notropis perpallidus Peppered shiner G3 S2 S2S3

Fish Notropis sabinae Sabine shiner G4 S2?

Fish Noturus eleutherus Mountain madtom G5 S2

Fish Noturus lachneri Ouachita madtom G2 S2

Fish Noturus placidus Neosho madtom G2 T S1 S1

Fish Noturus taylori Caddo madtom G1 S1

Fish Percina cymatotaenia Bluestripe darter G2 S3

Fish Percina maculata Blackside darter G5 S2

Fish Percina nasuta Longnose darter G3 S1 S1

Fish Percina pantherina Leopard darter G1 T S1 S1

Fish Percina phoxocephala Slenderhead darter G5 S2

(continued)

157
Table 2.21—Endangered, threatened, and other species of special concern in the aquatic study area (continued)

Group Species Common name Globala Federalb MOc ARc OKc

Fish Percina shumardi River darter G5 S2

Fish Percina uranidea Stargazing darter G3 S2

Fish Phenacobius mirabilis Suckermouth minnow G5 S1

Fish Polyodon spathula Paddlefish G4 S2?

Fish Scaphirhynchus platorynchus Shovelnose sturgeon G4 S1

Fish Typhlichthys subterraneus Southern cavefish G3 S3 S1

Herptile Cryptobranchus alleganiensis Ozark hellbender G4T3 S3

bishopi

Herptile Macroclemys temminckii Alligator snapping turtle G3G4 S1

Herptile Sternotherus carinatus Razorback musk turtle G5 S1

a Global ranks: see “Glossary of Terms” for definitions. b Federal ranks: C = candidate; T = threatened; E = endangered; PE = potentially endangered.

c State ranks: Denoted by S and a number (1–5) or letter code.

Source: see “Data Sources and Methods of Analysis” of this section.

mollusks, two crustaceans, and six fishes). Taxa with

G1 to G3 global ranks (excluding Federal status taxa)

include 6 aquatic insects, 15 mollusks, 20 crustaceans,

19 fishes, and 1 herptile. The remaining 50 taxa are

State ranked and include: 1 insect, 16 mollusks, 1

crustacean, 30 fishes, and 2 herptiles. In the Assessment

area, about 32, 50, and 26 percent of fishes, mussels,

and crayfishes, respectively, have Federal status, global

ranks, and/or State ranks (see previous analyses of

richness and density of these groups).

The degree of imperilment of aquatic organisms in

the study area as estimated by numbers of species with

Federal status may be conservative. For example, 18

species of freshwater mussels within the aquatic study

area are regarded as endangered or threatened by the

American Fisheries Society (Williams and others 1993),

and 14 received global ranks from The Nature Conservancy. However, only 6 species of freshwater mussels

have Federal status. Similarly, only 2 crayfishes in the

Assessment area have Federal status, but the American

Fisheries Society (Taylor and others 1996) recognized

13 as endangered or threatened, and The Nature

Conservancy considers 13 as globally rare. The scant

representation of aquatic insects on the lists of imperiled

fauna reflects the relatively incomplete documentation

of their distribution and status and is not unique to the

Assessment area (Murphy 1991). For other groups of

aquatic organisms, the discrepancy between Federal

status lists and other sources may be attributed, in part,

to the backlog in the listing process that is ongoing under

the Endangered Species Act (Reffalt 1991, Warren and

Burr 1994).

Federal status and other aquatic species of

special concern among hydrologic units. Endangered and threatened aquatic species were not distributed evenly among the hydrologic units (fig. 2.33), but

60 percent of the hydrologic units had at least one

Federal status aquatic species recorded on EOR’s. The

total number of Federal status species for the Assessment area is 14, but the number of Federal status

species ranged from 0 to 4 across watersheds (table

2.22). Hydrologic units with three or four Federal status

species were located in the southern Ouachita Mountains (Upper Little, Lower Little, and Upper Ouachita

watersheds), the Neosho-Illinois River Basin (Spring,

Lake O’ the Cherokees, Elk, and Illinois watersheds),

and the Sac watershed (Osage River drainage). Hydrologic units with one or two Federal status species were

scattered widely across the Assessment area.

The number of Federal status and other special

concern species recorded on EOR’s is not distributed

evenly among the hydrologic units (fig. 2.34). Total

numbers of Federal status, global rank, and State rank

aquatic species averaged 7.4 (two standard errors =

1.79) per hydrologic unit and ranged from 0 to 30

species. Seven hydrologic units had no Federal status or

other imperiled species, but 30 hydrologic units had

EOR’s for 6 or more imperiled species.

Two concentrations of hydrologic units showed

primary levels of total imperilment (10 to 30 species per

158
Figure 2.33—Number of endangered and threatened aquatic species by watershed.

4 species

3 species

2 species

1 species

No species

Oklahoma

Arkansas

Missouri

hydrologic unit) (fig. 2.34). One group is along the

southern edge of the Assessment area in the Ouachita

Mountains, and another is along the northeastern edge

of the Assessment area in the Upper Black River and

Upper St. Francis drainages and to a lesser extent the

Upper White River drainage. Hydrologic units of the

southern Ouachita Mountains with primary levels of

total imperilment included the Upper Little (30 imperiled

species), Mountain Fork (21 species), Lower Little (22

species), and Kiamichi (14 species) watersheds

(Kiamichi-Little drainage) and to the east, the Upper

Ouachita watershed (17 species; Ouachita-Saline

drainage). Hydrologic units within the Kiamichi-Little

drainage showed the highest levels of total imperilment

in the Assessment area. For perspective, the Upper

Little, Lower Little, and Mountain Fork watersheds

showed EOR’s comprising 24, 18, and 17 percent,

respectively, of Federal status and other special concern

aquatic species in the Assessment area. The second

concentration of watersheds with primary levels of total

imperilment includes: the Middle White watershed

(Upper White River drainage); the Spring, Current, and

Eleven Point watersheds (Black River drainage); and

the Upper St. Francis watershed. Of these, the Current

and Spring watersheds showed EOR’s representing 12

and 15 percent, respectively, of Federal status and other

159
imperiled species within the Assessment area. In the

western part of the Assessment area, one watershed in

the Arkansas River drainage (Robert S. Kerr Reservoir

watershed) and two in the Neosho-Illinois drainage

(Illinois and Spring watersheds) also showed primary

levels of total imperilment.

Secondary levels of total imperilment (seven to nine

species per hydrologic unit) tended to be associated with

hydrologic units adjacent to those with primary levels of

total imperilment (fig. 2.34). In the Ouachita Mountains,

for example, the Little Missouri and Ouachita Headwaters watersheds (Ouachita-Saline drainage), both with

secondary levels of total imperilment, complemented

watersheds in this province with primary levels of total

imperilment. Likewise, the Meramec watershed

(Meramec River drainage), Upper Black, Lower Black,

and Strawberry watersheds (Black River drainage), and

Little Red watershed (Upper White River drainage) lie

adjacent to watersheds with primary levels of total

imperilment in the northeastern portion of the Assessment area. The Sac watershed (Osage River drainage),

the Lower Neosho and Elk watersheds (Neosho-Illinois

drainage), Poteau and Dardanelle watersheds (Arkansas River drainage), and Bull Shoals Lake and Beaver

Reservoir watersheds (Upper White River drainage)

also showed secondary levels of total imperilment.

Tertiary levels of total imperilment (1 to 6 species per

hydrologic unit) were concentrated primarily in the

Osage and Gasconade River drainages as well as the

Arkansas River drainage (fig. 2.34). All hydrologic units

in the Gasconade River drainage and all but the Sac

watershed in the Osage River drainage show tertiary

levels of total imperilment. Likewise, all watersheds in

the Arkansas River drainage with the exception of the

Poteau, Dardanelle Reservoir, and Robert S. Kerr

Reservoir watersheds show tertiary levels of total

imperilment. The team emphasizes, however, that 16 of

23 watersheds with tertiary levels of total imperilment

had 1 to 6 imperiled species.

No consistent pattern was revealed for Federal

status or other species of special concern being associated with watersheds having high percentages of

national forest ownership. Some basins and watersheds

that have national forest lands have relatively high

numbers of Federal status and/or other species of

special concern (Kiamichi-Little, Upper Black, and

portions of the Ouachita-Saline and Upper White River

Table 2.22—Number of aquatic species with Federal status or

special concern status that are found in the aquatic study areaa

River basin Watershed code Federal Special

Watershed name (HUC) status status

Osage River Basin

H.S. Truman Reservoir 10290105 0 0

Sac 10290106 3 7

Pomme de Terre 10290107 1 1

South Grand 10290108 0 0

Lake of the Ozarks 10290109 0 1

Niangua 10290110 1 3

Lower Osage 10290111 2 6

Gasconade River Basin

Upper Gasconade 10290201 0 5

Big Piney 10290202 0 4

Lower Gasconade 10290203 1 5

Meramec River Basin

Meramec 07140102 0 9

Bourbeuse 07140103 0 1

Big 07140104 0 0

Upper St. Francis River Basin

Upper St. Francis 08020202 0 11

Neosho-Illinois River Basin

Lake O’ the Cherokees 11070206 3 6

Spring 11070207 3 10

Elk 11070208 3 7

Lower Neosho 11070209 2 9

Illinois 11110103 4 11

Arkansas River Basin

Dirty-Greenleaf 11110102 0 0

Robert S. Kerr Reservoir 11110104 1 10

Poteau 11110105 0 8

Frog-Mulberry 11110201 0 6

Dardanelle Reservoir 11110202 1 7

Conway- Pt. Remove 11110203 0 0

Petit Jean 11110204 0 1

Cadron 11110205 0 0

Fourche La Fave 11110206 0 0

Lower Ark-Maumelle 11110207 0 2

Kiamichi-Little River Basin

Kiamichi 11140105 1 14

Upper Little 11140107 3 30

Mountain Fork 11140108 1 21

Lower Little 11140109 3 22

Ouachita-Saline River Basin

Ouachita Headwaters 08040101 1 8

Upper Ouachita 08040102 3 17

Little Missouri 08040103 0 7

Upper Saline 08040203 1 5

Upper White River Basin

Beaver Reservoir 11010001 1 9

James 11010002 1 5

Bull Shoals Lake 11010003 1 8

Middle White 11010004 1 11

Buffalo 11010005 0 4

North Fork White 11010006 1 5

Little Red 11010014 1 7

Upper Black River Basin

Upper Black 11010007 2 9

Current 11010008 1 15

Lower Black 11010009 1 9

Spring 11010010 2 19

Eleven Point 11010011 1 10

Strawberry 11010012 0 7

HUC = hydrologic unit code.

a Data derived from State heritage program records; see text for definitions.

160
apparent from recent work documenting the distribution

and status of aquatic species (e.g., Pflieger 1996) that

comprehensive inventory efforts in some States are

given higher priority and greater support than in others.

The ability of natural resource managers to recognize

species threatened with extinction or experiencing

population declines depends primarily on the timeliness

and comprehensiveness of inventory information

available to them. The data base assembled by the team

for the report provides a basis for increased interstate

and Federal-State coordination of efforts to provide upto-date status information on aquatic species in the

Ozark-Ouachita Highlands.

Basins). Other basins have relatively low numbers of

both, notably those watersheds in the Arkansas River

and Gasconade River Basins.

Implications and Opportunities

Increased and coordinated efforts to inventory and

monitor aquatic species are needed within the Assessment area. The current information for the true status

(population sizes, trends, and threats) of many species is

so fragmentary that some species that are now considered imperiled may be undeserving of consideration

whereas other species may be in jeopardy of extinction

but go unrecognized (Williams and Neves 1992). It is

Figure 2.34—Levels of endangered, threatened, and special concern aquatic species by watershed.

Levels

Primary

Secondary

Tertiary

Insufficient data 

Oklahoma

Arkansas

Missouri

161
Commercially and Recreationally Important

Species

Question 2.9: What is the status of commercial

and recreational aquatic species within the

Assessment area?

In 1996, 35.2 million people 16 years of age and older

engaged in recreational fishing in the United States

(USDI FWS 1997c). Within the Assessment area,

fishing is one of the more popular outdoor activities (see

“Recreation,” Chapter 5 of the Ozark-Ouachita

Highlands Assessment: Social and Economic Conditions (USDA FS 1999a)). The Assessment area is

home to world-class fishing; popular fishing resorts;

thriving fishing guide services; major fishing boat and

fishing tackle manufacturers, wholesalers, and retailers;

and major professional fishing tournaments and champions. These aspects of recreational fishing are highly

visible and generate considerable cash flow for the

economies of the Assessment area.

Further evidence of the public’s interest in recreational fishing occurred when Missouri and Arkansas

voters approved special sales taxes that include funding

for improved management of recreational fisheries. This

increased funding, in part, finances land acquisition, new

or improved fishing access, and additional staff to

improve management of aquatic species. These new

taxes were not aimed solely at improving recreational

fishing; hunting, State park facilities, and other similar

outdoor activities and resources also were funded. Few

other States have had similar boosts in funding to bolster

budgets of fish and wildlife agencies.

The high level of recreational fishing, of course,

would not have developed had the fishery resources not

been available. While the early inhabitants of the

Highlands found plentiful stream and river fishery

resources, these environments have been significantly

altered by construction of dams, locks, levees, reservoirs, lakes, and ponds (see Chapter 1 of this report)

and by increasing demands on and harvest of fish.

Fishery managers respond to the challenge of altered

habitats by trying to manage for sustainable yield

(through natural fish reproduction) where possible.

When necessary, managers supplement and replenish

stocks with fish from hatcheries. The subsequent yields

are determined by sport and commercial angling pressure tempered by (1) the capability of the habitat to

sustain aquatic species, (2) the effectiveness of fishing

regulations to prohibit excessive and/or illegal take, and

(3) the ability of the fish and wildlife agency to direct

resources to improve habitat or increase fish stocking.

Managers meet changes in angling pressure and/or

harvest with changes that often include revised angling

regulations. Supplemented yield implies at least some

part of the harvest cannot be naturally sustained and

must be artificially boosted by supplemental stocking of

fishes. Yield is also tempered by the aquatic resources

available, hatchery capability, and funding support for

hatchery operations. Natural, sustainable yield is the

relative equilibrium that exists in many bass, bluegill, and

crappie fisheries where no stocking occurs. Examples

of supplemented yield are stocked trout fisheries where

anglers’ license fees finance the hatchery stockings that

allow harvest levels to remain at desired levels.

It is not possible in this report to define past, present,

and projected levels of game fish and commercial fish

species in other than general terms because the data are

not specific enough for the Assessment area. The data

are either State totals that include data outside the

Assessment area or are solely from selected commercial fisheries within the Assessment area.

In this section, the Aquatic Team discusses available

harvest information for commercial species of fishes

and mussels as well as trend analysis when the team

had more than 1 year of data. The team identifies

differences in legal definitions of game fish, commercial

fish, and mussel species among Assessment area

States. They also present information on the stocking of

non-native fish populations and the supplemental

stocking of selected native game fish species by State

and river drainages within the Assessment area.

162
 Key Findings

 1. Commercial fish harvesting within the Assessment

area is limited to Arkansas waters. The only legal

commercial fishing in Oklahoma occurs within the

Eufaula Reservoir just west of the Assessment

area, where one individual has a commercial

license.

 2. Commercial fish harvests and the number of

commercial fishers are somewhat stable.

 3. Mussel harvesting regulations in Arkansas govern

whether an area is open, closed, or set aside as a

refugium (protected area) within an open area.

 4. Oklahoma had only one licensed shell (mussel)

buyer in 1997. The majority of the buying is of

shells from backwater areas of lakes in northeast

Oklahoma; the few species in this area with thick,

large shells and little surface erosion are in demand

commercially.

 5. Demand for shells is driven by the market for pearl

blanks (a round piece of shell inserted in commercial pearl oysters to stimulate pearl formation).

Actual harvest levels are lower than harvest limits

because of the pearl industry’s requirements for a

specific color and size.

 6. Legally designated species of game and commercial fish vary by State, although sought-after

species differ little among States. Designating a

species as a game fish generally regulates its

harvest more closely than harvests of other recreational species.

 7. Significant efforts have been made—mostly

introductions of non-native fish species—to manage open-water habitats of large reservoirs within

the Assessment area and to utilize adequately cool

and cold water habitats within and downstream

from these reservoirs.

 8. State and Federal fisheries-management agencies

protect native stocks of smallmouth bass, walleye,

and sauger by foregoing some stocking opportunities that might contaminate these native stocks

genetically. Where supplemental stocking is needed

in habitats containing protected native species,

hatcheries are using spawners of the same genetic

stock as the protected native species found in the

receiving water bodies.

Data Sources and Methods of Analysis

Arkansas, Missouri, and Oklahoma agencies that

license such activities furnished the most recent commercial fishing and mussel harvesting information.

Because of both personnel constraints and fairly

consistent trends in harvests (Armstrong 1997), Arkansas stopped collecting data on commercial fishing in

1992 except for a few selected lakes. The Arkansas

Game and Fish Commission provided data about mussel

harvests from 1992 through 1996 and commercial fish

harvests in the Nimrod and Blue Mountain Reservoirs

from 1995 through 1997.

The Oklahoma Department of Wildlife Conservation

provided data about commercial fishing harvests for

1995 and mussel harvests for 1986 through 1995.

Similarly, the Missouri Department of Conservation

provided data for commercial fish harvests from 1945 to

1994 and for shell harvests from 1992 through 1996.

The Aquatic Team derived lists of species of legal

game and commercial fish from the Wildlife Codes

(hunting and fishing regulations) of each State. The

team found that, in many cases, fish family groups were

listed as game and/or commercial species when, in fact,

a particular species in a group does not grow large

enough to have angling or commercial value. Therefore,

the team attempted to identify only the species within

the fish family that might have commercial or angling

value. Thus, channel catfish are shown as a game and

commercial species whereas small “madtom” catfish

are not. The Oklahoma buyer furnished the list of

commercial species of mussels bought there. The team

combined an in-house update of Arkansas commercial

mussels species with a list found in “Arkansas Mussels”

(Harris and Gordon, n.d.). Similarly, they used the list of

commercial species from “Missouri Naiades” (Oesch

1984). These last two publications were written before

a rise in demand for shells for the pearl trade and reflect

a wider range of species than is currently most in

demand (Downing 1997, Harris 1997a). The team

examined State regulations for shell harvesting to

determine what is and is not legal. They found commercial harvest records are somewhat ambiguous because

different species are sometimes grouped together.

The team obtained stocking records, generally from

1994 into 1997, from each Assessment State. They used

information about major species of game fish not native

163
to the receiving waters and, in several cases, species

that are non-reproducing hybrid game fish. Because the

team knew that largemouth bass, bluegill and other

panfish, and channel catfish are stocked extensively

across the Assessment area, they felt it likely that most

Assessment area waters contain these fish (with the

exception of some of the trout waters). Therefore, the

Aquatic Team did not attempt to examine bass, panfish,

and catfish stocking records.

Patterns and Trends

Mussel harvest. The Arkansas Game and Fish

Commission, Missouri Department of Conservation, and

Oklahoma Department of Wildlife Conservation regulate

freshwater shell harvesting in their respective States.

Shell buyers are not only required to have a license but

must also report purchases annually or quarterly.

Waters open for commercial shell harvesting in

Missouri are restricted to the Missouri River (which

represents the northern border of the aquatic study

area) and the Mississippi and lower St. Francis Rivers

(which are just outside the eastern border) (MO DC

1997).

All waters from Pulaski County, AR, northeast to

Randolph County, AR—the most eastern Arkansas

counties in the Assessment area—are open for mussel

harvesting year round. The remainder of the State in the

Assessment area is closed to commercial mussel

harvesting except for (1) the Arkansas River from the

Oklahoma State line to Pulaski County; (2) the lower

Petit Jean River; (3) the lower Fourche La Fave River;

(4) sections of Cadron, North Cadron, and Point Remove Creeks; and (5) the White and Strawberry Rivers.

Portions of the lower White, Black, Spring, and St.

Francis Rivers have areas designated as refugia (protected areas) (AR GFC 1995a).

All Oklahoma waters are open for commercial mussel

harvesting with the exception of Tenkiller Lake, the

Kiamichi and Illinois Rivers, and mussel sanctuaries that

include the first 2 mi of rivers entering the State and the

first 2 mi below impoundments (OK DWC 1996b).

However, according to the licensed shell buyer (Downing

1997), the demand is only for the thicker shells of a few

species with little shell-surface erosion. These preferences restrict harvesting to a few backwater areas of

reservoirs within or west of the Assessment area.

Although these three States restrict species and

minimum size allowed for harvest, the regulations allow

more species to be harvested than are currently of

commercial interest. Table 2.23 lists species currently

harvested or deemed to have had commercial value

since the 1980’s. The 1996 harvest of mussels in

Missouri apparently was concentrated in Pools 11, 17,

18, and 19 of the Mississippi River and consisted of

washboard, threeridge, and mapleleaf mussels

(Buchanan 1997). In Arkansas, the 1996 harvest

consisted of 42 percent washboard, 34 percent

threeridge, 8 percent ebonyshell, 5 percent mapleleaf, 3

percent mucket, and 8 percent a mix of species

(Burnley 1996, 1997). The Oklahoma harvest was

predominantly mapleleaf and threeridge mussels

(Wallace 1996).

The Aquatic Team collected data on the mussels

bought in Missouri from 1989 through 1996. The least

productive year was 1992 when harvesters collected

only 8,808 pounds of mussels worth $10,814. The peak

year was 1995, when 642,757 pounds were collected

worth an estimated $941,189. In 1989, harvesters

collected 399,086 pounds for $199,086, and 1996 yielded

a harvest of 109,688 pounds worth $155,798. Though

these data are not from the Assessment area, they are

relevant due to the proximity of the harvested area to

the Assessment area (Koch 1993, Buchanan 1997).

The Arkansas harvest of mussels ranged from

452,892 pounds valued at $256,759 in 1992 to 1,250,958

pounds in 1996 with an estimated value of $1,388,661

(Todd 1993, 1994, 1995; Burnley 1996, 1997). As with

Missouri, the peak Arkansas harvest was in 1995, with

2,191,198 pounds valued at $2,589,782. For 1996, the St.

Francis River supported 30 percent of the total reported

harvest, the White River 21 percent, the Black River 10

percent, the Arkansas River about 9 percent, and the

Ouachita River less than 0.1 percent. In 1996, the

Fourche La Fave River produced about 11 percent of

that year’s harvest (the only year of the 5 years of

record showing a harvest from this river). These

reports are not sufficiently detailed to be able to determine what percent of Arkansas’ harvest of mussels

was from the Assessment area (Todd 1993, 1994, 1995;

Burnley 1996, 1997).

Oklahoma’s harvest ranged from 459,669 pounds

purchased for $242,464 in 1986 to a peak of 992,947

pounds purchased for $1,327,597 in 1990; 338,277

164
165

pounds were purchased for $609,850 in 1995. From

1986 to 1995, the lowest harvest was in 1992 when

161,834 pounds were purchased for $162,625 (Wallace

1996). The Oklahoma report did not specify locations of

harvests.

For 1995, the peak harvest year, the total for the

three States was 3,172,232 pounds of shells harvested

and purchased from the pickers for an estimated value

of $4,140,821. (Note that this dollar value does not

reflect what the buyers ultimately received for the

shells.) Arkansas accounted for 69 percent of this

harvest; Missouri, 20 percent; and Oklahoma, 11

percent. The Aquatic Team estimated that from 5 to 15

percent of this harvest was from within the Assessment

area in Arkansas and Oklahoma.

Mussel harvesting appears to be driven by the

market for shells used in the cultured pearl industry.

Also playing a role are depletion of mussel beds and

regulation of harvests through minimum size limits, area

closures, and season limits (Koch 1993). In 1996,

Arkansas raised license fees but found that when prices

are high and shells are abundant, higher license fees are

no deterrent to shell pickers and buyers (Burnley 1996,

1997).

Experts anticipate that shell harvest will decline

because the market for pearl blanks has decreased due

to decimation of eastern pearl oysters from disease. As

soon as the problems with eastern pearl culture are

solved, market demand for shells is likely to increase

again.

Commercial fish harvest. Species legally available

for harvest in Arkansas, Missouri, and Oklahoma are

presented in table 2.24 minus those that (1) do not reach

minimum size requirements, (2) are quite rare, or (3) are

present in areas either not open to commercial harvest

or that are open but unlikely to be commercially fished.

Oklahoma considered all non-game fish species

available for commercial harvest; however, only three

fish families—sucker, gar, and minnow—are harvested.

These three families contain up to nine potentially

harvestable species. The three States present the

commercial harvest information by fish family only, so

Table 2.23—Commercial mussel species in the aquatic study area, by State

Species Common name Arkansas Missouri Oklahoma

Actinonaias ligamentina Mucket X X

Amblema plicata Threeridge X X

Cyclonaisa tuberculate Purple wartyback X

Cyprogenia aberti Western fanshell X

Ellipsaria lineolata Butterfly X X

Elliptio dilatata Spike X X

Fusconaia ebena Ebonyshell X X X

Fusconaia flava Wabash pigtoe X X

Lampsilis cardium Plain pocketbook X

Lampsilis siliquoidea Fatmucket X

Lampsilis teres Yellow sandshell X X

Ligumia recta Black sandshell X

Megalonaias nervosa Washboard X X X

Obliquaria reflexa Threehorn wartyback X X X

Obovaria olivaria Hickorynut X

Plectomerus dombeyanus Bankclimber X X

Pleurobema coccineum Round pigtoe X X

Potamilus purpuratus Bleufer X X

Ptychobranchus occidentalis Ouachita kidneyshell X

Quadrula metanevra Monkeyface X X X

Quadrula nodulata Wartyback X X

Quadrula pustulosa Pimpleback X X X

Quadrula quadrula Mapleleaf X X X

Tritogonia verrucosa Pistolgrip X X

Total 22 18 7

Source: Harris (1997a), Oesch (1984), Downing (1997).
Table 2.24—Game and commercial fish species of the Assessment area, by State

 Arkansas Missouri Oklahoma

Species Common name Game Commercial Game Commercial Game Commercial

Acipenser fulvescens Lake sturgeon X

Ambloplites ariommus Shadow bass X X

Ambloplites constellatus Ozark bass X X

Ambloplites rupestris Rock bass X X

Ameiurus catus White catfish X X X

Ameiurus melas Black bullhead X X

Ameiurus natalis Yellow bullhead X X

Ameiurus nebulosus Brown bullhead X X

Amia calva Bowfin X X

Aplodinotus grunniens Freshwater drum X X

Atractosteus spatula Alligator gar X X X X

Carpiodes carpio River carpsucker X X

Carpiodes cyprinus Quillback X X

Carpiodes velifer Highfin carpsucker X X

Catostomus commersoni White sucker X X X

Centrarchus macropterus Flier X

Ctenopharyngodon idella Grass carp X X

Cycleptus elongatus Blue sucker X X X

Cyprinus carpio Common carp X X X

Esox lucius Northern pike X X X

Esox masquinongy Muskellunge X X

Esox masquinongy x lucius Tiger muskellunge X X

Esox niger Chain pickerel X X

Hypentelium nigricans Northern hogsucker X

Hypophthalmichthys molitrix Silver carp X X X

Hypophthalmichthys nobilis Bighead carp X X X

Ictalurus furcatus Blue catfish X X X X X

Ictalurus punctatus Channel catfish X X X X X

Ictiobus bubalus Smallmouth buffalo X X X

Ictiobus cyprinellus Bigmouth buffalo X X X

Ictiobus niger Black buffalo X X X

Lepisosteus osseus Longnose gar X X X

Lepisosteus platostomus Shortnose gar X X X

Lepomis cyanellus Green sunfish X

Lepomis gibbosus Pumpkinseed X

Lepomis gulosus Warmouth X X

Lepomis macrochirus Bluegill X

Lepomis megalotis Longear sunfish X

Lepomis microlophus Redear sunfish X

Lepomis miniatus Redspotted sunfish X

Micropterus dolomieu Smallmouth bass X X X

Micropterus punctulatus Spotted bass X X X

Micropterus salmoides Largemouth bass X X X

Minytrema melanops Spotted sucker X X X

Morone chrysops White bass X X X

Morone mississippiensis Yellow bass X X

Morone saxatilis Striped bass X X X

Monore saxatilis x chrysops Hybrid striped bass X X

Moxostoma anisurum Silver redhorse X X X

Moxostoma carinatum River redhorse X X X

Moxostoma duquesnei Black redhorse X X X

Moxostoma erythrurum Golden redhorse X X X

Moxostoma macrolepidotum Shorthead redhorse X X X

Moxostoma poecilurum Blacktail redhorse X

Oncorhynchus clarki Cutthroat trout X

(continued)

166
Table 2.24—Game and commercial fish species of the Assessment area, by State (continued)

 Arkansas Missouri Oklahoma

Species Common name Game Commercial Game Commercial Game Commercial

Oncorhynchus mykiss Rainbow trout X X X

Polyodon spathula Paddlefish X X X X

Pomoxis annularis White crappie X X X

Pomoxis nigromaculatus Black crappie X X X

Pylodictis olivaris Flathead catfish X X X

Salmo trutta Brown trout X X X

Salvelinus fontinalis Brook trout X X X

Salvelinus namaycush Lake trout X

Scaphirhynchus platorynchus Shovelnose sturgeon X X

Stizostedion canadense Sauger X X X

Stizostedion canadense x vitreum Saugeye X

Stizostedion vitreum Walleye X X X

Total 51 30 27 30 15 9

Source: see “Data Sources and Methods of Analysis” of this section.

further breakdown by species is not possible from their

reports.

Arkansas waters open to commercial fishing (AR

GFC 1996) within the Assessment area consisted of (1)

the lower Fourche La Fave River, (2) the entire Arkansas River, (3) the lower Petit Jean River, (4) portions of

the lower White River, and (5) the Black River. No

commercial fish harvest is occurring in Arkansas lakes

and reservoirs within the Ozarks (Oliver 1997). Commercial fish harvest is occurring in the Arkansas River,

Nimrod Lake on the Fourche La Fave River, and Blue

Mountain Lake on the Petit Jean River. With the

exception of the two lakes, no efforts have been made

since 1992 to compile data about commercial harvests

for Arkansas (Armstrong 1997). From July 1, 1987,

through June 30, 1988—the last year of record for the

entire State of Arkansas—22,955,319 pounds of fish

were commercially harvested worth an estimated

$8,598,055 (Farwick 1997). Of that figure, 5,023,626

pounds were harvested from the whole Arkansas River

system, worth an estimated $2,166,122. Fishers harvested over 2 million pounds each of buffalo and catfish

from the Arkansas River.

For the 1996 through 1997 and 1995 through 1996

commercial fishing seasons, four commercial fishers

harvested at Nimrod Lake and three at Blue Mountain

Lake, according to Arkansas Game and Fish Commission reports (Limbird and Ahlert 1993, 1996, 1997).

During the 1994 through 1995 season, there was one

commercial fisher at Nimrod Lake and four at Blue

Mountain Lake. For the above three seasons, commercial harvests at Blue Mountain Lake were 9,362, 14,173,

and 40,432 pounds of fish, respectively. Buffalo and

carp made up 46 and 32 percent, 44 and 45 percent, and

45 and 43 percent, respectively, of the harvest for the

three seasons at Blue Mountain Lake. The harvests at

Nimrod Lake were 42,480, 57,764, and 17,638 pounds

for the years 1996 to 1997, 1995 to 1996, and 1994 to

1995, respectively. For these times, the percent catch by

weight of buffalo and carp was 90 and 2 percent, 92

and 1 percent, and 93 and 2 percent, respectively, for

the three seasons at Nimrod Lake. Flathead catfish

made up 11 percent of the harvest by weight at Blue

Mountain Lake during 1996 to 1997, 5 percent of the

harvest by weight the preceding year, and 2 percent in

1994 to 1995. Numbers harvested for the same periods

were 127, 108, and 88 flatheads. For Nimrod Lake, the

flathead catfish harvest by weight (percentages) and

numbers harvested were 2 percent and 115 flatheads

during 1996 to 1997, 0.8 percent and 51 flatheads during

1995 to 1996, and 2.5 percent and 33 flatheads in 1994

to 1995. Gar harvests for the 3 seasons ranged from 33

to 637 gar from Blue Mountain. From 0 to 230 gar were

caught over the 3 seasons at Nimrod. Combined netted

species of game fish amounted to 1.5 percent or less of

the harvest (by weight per year per lake) and represented an insignificant loss. The game fish losses are

minimized by fishing gear being restricted to gill and

167
trammel nets of 31⁄2-inch bar mesh and larger. Statewide

commercial fishing efforts appear to be consistent as

measured by sales of commercial fishing licenses. It is

also believed that anglers are using commercial harvests

for personal use, with a decline in what is sold

(Armstrong 1997). In addition, some drops or shifts in

license sales and fishing efforts have occurred, likely the

result of Arkansas fish consumption advisories and

commercial harvest closures in response to elevated

mercury levels in fish in some locales. These drops

occurred on a localized basis in the lower Ouachita

River Basin, south of the Assessment area.

The report “Missouri Commercial Fish Harvest,

1993” (Robinson 1995) had the most recent information

on Missouri fish harvests available at the time of this

Assessment; 1994 and 1995 tables were compiled later

(Robinson 1998). Waters open to commercial fishing in

Missouri all lie to the north and east of the Assessment

area. As is true for mussel harvests, only the Missouri,

Mississippi, and lower St. Francis Rivers are open to

commercial fishing (MO DC 1997). From 1993 through

1995, the number of licensed commercial fishers with

gear was 340, 319, and 395, respectively. A commercial

fishing license is also required of mussel harvesters, but

their nets and other fishing gear are not regulated. Most

commercial fishers (94 percent) have reported harvesting fewer than 5,000 pounds of fish annually since the

1988 license period. This level of harvesting strongly

suggests that few anglers make much money from

commercial fishing (Robinson 1995).

Removal of all catfish species from the commercial

fish list on the Missouri River (which became effective

July 1, 1992) is also considered to have caused a drop in

the number of commercial fishers (Robinson 1995). The

reported 1993 Missouri commercial fish harvest was

566,000 pounds with common carp and all buffalo

contributing 47 percent of the total harvest by weight.

The 1994 harvest was 668,000 pounds, with 49.5 percent

buffalo and common carp by weight. The 1995 harvest

was 541,000 pounds, with 57 percent buffalo and

common carp by weight. The grass carp harvest has

grown from 8,787 pounds in 1993 to 15,330 pounds in

1994 and 21,366 pounds in 1995. The grass carp harvest

was only 4 pounds in the St. Francis River in 1993, with

none reported harvested in the St. Francis the last 2

years of record (1994 and 1995). In 1994, approximately

53 percent of the grass carp harvest was from the

Missouri River, and 63 percent was harvested from the

Mississippi River in 1995. Since 1945, an average of 23

commercial anglers per year have fished the St. Francis

River fairly constantly. Both the Mississippi and Missouri

Rivers have seen drops in numbers of commercial

fishers since the early 1980’s, when peaks of nearly 700

anglers on the Mississippi and over 1,000 anglers on the

Missouri occurred. The 1995 totals for the 2 rivers

indicate the presence of an estimated 194 and 124

commercial fishers, respectively. The Mississippi River’s

estimated number of commercial fishers has remained

fairly level since 1988, but the precipitous drop in commercial fishers on the Missouri River bottomed out in

1994 at 110. Commercial fishing is anticipated to remain

fairly constant on these waters unless (1) license fees

increase significantly, (2) consumption advisories are

imposed, (3) further restrictions on the harvest of catfish

are imposed, or (4) the market for fresh fish changes

dramatically. As previously noted, few commercial

fishers make their living solely from commercial fishing.

In 1995, Oklahoma issued one commercial fishing

license that restricted the fisherman to one area in Lake

Eufaula (Wallace 1996). This lake is just to the west of

the Assessment area. From 1994 to 1995, the number of

commercial fishers dropped from two to one for the

same area. Commercial fish harvests in Lake Eufaula

decreased from 11,725 pounds in 1994 to 10,991 pounds

in 1995. The commercial fish harvest from Lake

Eufaula during 1995 comprised 9,166 pounds of buffalo,

870 pounds of common carp, and 955 pounds of gar.

Turtles can be harvested with a fishing license in

Missouri, Arkansas, and Oklahoma. Oklahoma opened

commercial turtle harvesting in 1994 and requires either

a buyer’s or a harvester’s license (OK DWC 1996a).

Arkansas and Missouri commercial fishing licenses

allow the turtles to be harvested for commercial sales.

Alligator snapping turtles are not allowed to be taken or

harvested in Arkansas or Missouri; this prohibition shut

down a growing industry in Arkansas (Armstrong

1997). Missouri commercial fishing records (Robinson

1995, 1998) do not include turtle harvests, so turtle

harvesting is either not occurring or is not being reported

in Missouri. Arkansas commercial turtle harvest records

have not been compiled. For 1995, Oklahoma (Wallace

1996) reported the harvest of 18,946 turtles of 11

168
species. Red-eared turtles comprised nearly 45.5

percent of the turtles purchased; common snapping

turtles, smooth soft-shell turtles, and spiny soft-shell

turtles were the next most common species harvested.

In 1995, buyers paid turtle harvesters over $28,000.

Origins of these harvested turtles were not given in the

Oklahoma report.

Recreational fisheries. Designated species of

game fish are listed in table 2.24. These listed species

reflect named species of game fish or members of

families of game fish sought by anglers. While Arkansas

includes the members of the sunfish family as game

fish, Oklahoma does not; Missouri lists only rock bass

and warmouth as game fish within this fish family

grouping (AR GFC 1996, MO DC 1997, and OK DWC

1996a). The paddlefish, the recreational harvest of

which is regulated by the three States, is not listed as a

game species by Oklahoma. Of the three States,

Arkansas is the only one that includes bullhead catfish

as a game species (because of its inclusion in the catfish

family); however, no State limit is set for their harvest.

Arkansas imposes a 50-fish limit on sunfish. Missouri

also has a 50-fish limit on sunfish by virtue of having a

50-fish limit for all non-game fish species. Missouri has

a 15-fish limit on rock bass and warmouth. Oklahoma

does not impose a limit on the number of sunfish that

can be harvested. While Oklahoma does not list hybrid

striped bass as a game fish, it does regulate harvest with

creel limits (the number of fish that can be harvested).

The full suite of game fish listed for the three States

reflects what recreational fishers seek. In addition,

many—if not most—of the commercial species are also

caught and harvested. While the three States may have

different lists of game fish, in practice, similar species

are being managed through the imposition of statewide

creel limits.

Arkansas is stocking eight additional species of game

fish in waters within the Arkansas portion of the

Assessment area besides the standard bass, bluegill, and

other sunfish and channel catfish stockings (table 2.25)

(Armstrong 1997). The stockings are conducted to:

(1) develop self-sustaining fisheries; (2) provide unique

sport-fishing opportunities; and (3) encourage nonreproducing species to take advantage of unique

habitats (e.g., reservoirs and their tail water fisheries)

and/or underutilized forage fish. Trout are stocked in

many of the large reservoirs (at least seasonally, when

and where water temperature and oxygen levels will

support the trout). They are also stocked in the cool to

cold tailwaters downstream from the reservoirs with

deep releases of cold water. Striped bass and hybrid

striped bass (a hybrid of striped bass and white bass)

are stocked in many of the large reservoirs to prey upon

shad in the open water environment, particularly the

larger-sized shad. Hybrid striped bass and saugeye (a

hybrid of walleye and sauger) are stocked in some

smaller waters to reduce the numbers of forage species,

including underutilized sunfish. Walleye are stocked in

several reservoirs in Arkansas to supplement natural

reproduction of established walleye populations.

Table 2.25—Additional game fish speciesa stocked in study area water bodies, by State and river basin

 State River basin

Upper Kiamichi- Neosho- Ouachita- Upper St. Upper

Species AR MO OK Arkansas Black Gasconade Little Meramec Illinois Osage Saline Francis White

Striped bass X X X X X X X

Hybrid striped bass X X X X X X X X X

Saugeye X X X X X

Walleye X X X X X X X X X X X

Muskellunge X X

Rainbow trout X X X X X X X X X X X X

Cutthroat trout X X X

Brook trout X X X

Brown trout X X X X X X X X X X

Flathead catfish X X X

a Game fish species in addition to largemouth bass, sunfish, and catfish, which are stocked in each of the three States and all of the river basins.

Source: see “Data Sources and Methods of Analysis” of this section.

169
Missouri implements an ongoing stocking program

very similar to that of Arkansas with the addition of trout

stocking in cold water springs such as the immensely

popular Bennett Springs State Park and several other

put-and-take trout stream fisheries (Wulff 1997). Missouri also has a number of self-sustaining rainbow trout

fisheries in cold water streams and springs within the

Assessment area (MO DC, n.d.). Oklahoma is stocking

five additional game fish species in similar reservoir and

tailwaters situations (Smith 1997, Harper 1997).

The Assessment States are taking care not to tamper

with the genetic stock of the region’s fishes. All three

States are avoiding stocking sauger and saugeye in

several drainages that could genetically contaminate

native populations of sauger. To protect native walleye

populations, Missouri is raising six different strains to

ensure the genetic integrity of different native river runs

of walleye (Wulff 1997). Genetic research on smallmouth bass from eastern Oklahoma and throughout its

range has identified Neosho and Ouachita forms of

smallmouth bass as being distinct from Upper Mississippi River and Ohio River drainage forms (Stark and

others 1995). The Neosho form of smallmouth bass is

found in the Arkansas River tributaries draining the

southern and western Ozark Highlands; the Ouachita

form is found within the Ouachita Mountains in southeastern Oklahoma and southwestern Arkansas (which

includes the Little and Ouachita Rivers and their

tributaries). With such recent findings, all three States

are exercising care in managing smallmouth bass stocks

to ensure the genetic integrity of this species.

Implications and Opportunities

The era of major introductions of new species into

the Assessment area is probably over because it is fairly

likely there will not be any new reservoirs or major

changes made in management of existing reservoirs and

their water releases. It is possible that some species

manipulation could still occur. For instance, if Arkansas

experiences a great deal of success with brook trout

and/or cutthroat trout, the Missouri Department of

Conservation and/or the Oklahoma Department of

Wildlife Conservation may add one of both of these

species to their trout stocking programs. Lake trout

stocked in Greers Ferry Lake from 1986 through 1989

apparently spawned at least once—a few offspring of

the stocked trout have shown up in recent harvests

(Perrin 1997). Whether this one-time reproduction from

the original stockings will also fade out as did the

original stocked fish or whether reproduction of the lake

trout will continue to grow, resulting in a major new

fishery, is presently unknown.

It is anticipated that fisheries management throughout

the Assessment area will increasingly focus on maintaining or restoring significant warm-water and coolwater stream fisheries and improving game-fish populations and angling in progressively smaller water bodies

as time goes on. Emphasis on managing trout and

reservoir game fish is not likely to diminish. While public

management efforts for trout and reservoir fisheries are

quite visible, considerable technical assistance is still

available to the landowner for management of private

waters. Bass, bluegill, crappie, and catfish are still the

“species of choice” of recreationists in the Assessment

area.

Commercial mussel harvesting is driven by the

overseas demand for shell blanks for the cultured pearl

industry. Mussel harvesting needs to be monitored to

ensure sustainability of the harvested species as well as

other species that may be indirectly affected by harvest

activities. Uniformity of harvest regulations (including

minimum shell sizes, season dates, and time of day open

for harvest) and uniformity of reporting would support

management of harvests within the Assessment area

and beyond. Knowledge of the source of shells—both

in-State and out-of-State—seems necessary to efficiently monitor and protect the resource.

Commercial fish harvesting within the Assessment

area is restricted to Arkansas waters at this time. Lack

of analysis of required commercial fishers reports and

lack of close monitoring of the fishing (at other than

Blue Mountain and Nimrod Lakes) is seen as a handicap for efficient fisheries management. State fish and

game agencies in the Highlands may wish to remind the

general public periodically that commercial fishing is

harvesting a renewable resource, and as such, can be

incorporated into a management scheme to improve

recreational fishing. Commercial fishing is a lifestyle of

some and in most cases is compatible with management

objectives of the State agencies and the public they

serve. Commercial turtle harvesting may need closer

scrutiny to determine the sustainability of the Assessment area’s resources in this regard.

170
Management of recreational fish species is an

evolving science. Great strides in improving habitat and

populations have been made and will continue to be

made. Working with landowners on the myriad of small

lakes and ponds throughout the Assessment area

provides continued opportunities to meet demand for

quality recreational fishing. Conserving the native

genetic stocks of game fish is imperative. Further

analysis of the genetics of smallmouth bass, walleye,

rock bass, warmouth, and other sought-after species is

possibly warranted to ensure the integrity of existing

populations. Continuing research on expectations of

recreational anglers is important in focusing management to improve the anglers’ experiences on these

waters. Citizen involvement in conservation and restoration programs such as Missouri and Arkansas Stream

Teams will continue to mobilize resources to restore and

protect the fishing quality of Assessment area waters.

Professional biologists and conservation agencies need

to work diligently with users of aquatic resources and

serve as support for grass-roots efforts like the Stream

Teams to restore, protect, and enhance the plentiful

aquatic resources of the Assessment area.

Management Indicator Species

Question 2.10: What management indicator

species are located within the Assessment area,

and what is their potential role for the aquatic

resources?

The National Forest Management Act calls for the

selection and use of “management indicator species”

(MIS) as a means to evaluate and monitor species and

their habitats during project or forest planning and

through project or forest plan implementation and

follow-up. Implementing regulations in the Code of

Federal Regulations (CFR) state:

In order to estimate the effects of each planning

or project alternative on fish and wildlife populations, certain vertebrate and/or invertebrate

species present in the area shall be identified and

selected as management indicator species and the

reasons for their selection will be stated. These

species shall be selected because their population

changes are believed to indicate the effects of

management activities. In the selection of management indicator species, the following categories

shall be represented where appropriate: endangered and threatened plant and animal species

identified on State and Federal lists for the planning

area; species with special habitat needs that may

be influenced significantly by planned management

programs; species commonly hunted, fished, or

trapped; non-game species of special interest; and

additional plant or animal species selected because

their population changes are believed to indicate

the effects of management activities on other

species of selected major biological communities or

on water quality (36 CFR, 1995).

This selection process is identified in 36 CFR Chapter II (7-1-95 edition) and will be followed in the revision

of national forest plans unless superseded by new or

additional direction. The base lists of aquatic species

from which to choose MIS are contained in this section

and the “Endangered, Threatened, and Other Aquatic

Species of Special Concern” section of this chapter.

Planners are not restricted solely to these lists of MIS

candidates, but these lists represent a starting point for

further analysis and consultations.

 Key Findings

 1. Lists of fish, mussels, crayfish, and aquatic insects

gathered during this Assessment include data about

their special status as reported and ranked by

Federal and State agencies, The Nature Conservancy, and the American Fisheries Society; such

rankings can form the basis for the selection of

management indicator species for forest plan

revision.

 2. The American Fisheries Society identified 19 fish,

76 mussel, and 59 crayfish species that occur in the

Highlands as endangered, threatened, of special

concern, or currently stable.

Data Sources and Methods of Analysis

Source tables for different MIS candidates were

developed, as discussed in the respective subsections

concerning fish, crayfish and mussels. Three articles in

Fisheries, a journal of the American Fisheries Society,

171
Table 2.26—Fish species in the aquatic study area ranked as endangered, threatened, or of special

concern by the American Fisheries Societya

Special

Species Common name Endangered Threatened concern

Acipenser fulvescens Lake sturgeon X

Amblyopsis rosae Ozark cavefish X

Crystallaria asprella Crystal darter X

Cycleptus elongatus Blue sucker X

Etheostoma cragini Arkansas darter X

Etheostoma moorei Yellowcheek darter X

Etheostoma nianguae Niangua darter X

Etheostoma pallididorsum Paleback darter X

Lythrurus snelsoni Ouachita Mountain shiner X

Macrhybopsis meekib Sicklefin chub X

Notropis perpallidus Peppered shiner X

Noturus lachneri Ouachita madtom X

Noturus placidus Neosho madtom X

Noturus taylori Caddo madtom X

Percina cymatotaenia Bluestripe shiner X

Percina nasuta Longnose darter X

Percina pantherina Leopard darter X

Percina uranidea Stargazing darter X

Polyodon spathula Paddlefish X

Total 0 11 8

a Rankings may differ from those assigned by the USDI Fish and Wildlife Service.

b Species within the aquatic study area but outside the Assessment area.

Source: Williams and others (1989b).

provided the rankings for this section (Williams and

others 1989b, 1993; Taylor and others 1996).

Patterns and Trends

Patterns and trends for MIS species are covered in

preceding sections of this report. The American Fisheries Society rankings are given in tables 2.26 through

2.28. The ranking categories are as follows: (1) endangered—a species or subspecies in danger of extinction

throughout all or a significant portion of its range; (2)

threatened—a species or subspecies likely to become

endangered throughout all or a significant portion of its

range; (3) special concern—a species or subspecies

that may become endangered or threatened by relatively

minor disturbances to its habitat and deserves careful

monitoring of its abundance and distribution; (4) currently stable—a species or subspecies the distribution of

which is widespread and stable and is not in need of

immediate conservation management actions (Williams

and others 1993). The fish species list (table 2.26)

predates the mussel and crayfish lists and was not

developed with the “currently stable” category. American Fisheries Society rankings do not convey official

status under the Endangered Species Act (ESA) even

though they contain categories of threatened and

endangered species; Federal rankings under the ESA

supersede State and AFS rankings. Federal rankings

can be found in the “Endangered, Threatened, and

Other Aquatic Species of Special Concern” section in

this chapter and in table 2.21.

Implications and Opportunities

Lists of species for the aquatic environments of the

Assessment area are presented in preceding sections of

this chapter. These lists can serve to begin the refinement process in selecting MIS for the aquatic environments in the Highlands. While identification and use of

MIS is mandated by regulations governing national

forest planning, any agency can find MIS useful at any

decision or project level.

172
Table 2.27—Mussel species in the aquatic study area ranked as endangered, threatened, of special concern,

or currently stable by the American Fisheries Societya

Special Currently

Species Common name Endangered Threatened concern stable

Actinonaias ligamentina Mucket X

Alasmidonta marginata Elktoe X

Alasmidonta viridis Slippershell X

Amblema plicata Threeridge X

Anodonta suborbiculata Flat floater X

Anodontoides ferussacianus Cylindrical papershell X

Arcidens confragosus Rock-pocketbook X

Arkansia wheeleri Ouachita rock-pocketbook X

Cumberlandia monodonta Spectaclecase X

Cyclonaias tuberculata Purple wartyback X

Cyprogenia aberti Western fanshell X

Ellipsaria lineolata Butterfly X

Elliptio crassidens Elephant-ear X

Elliptio dilatata Spike X

Epioblasma curtisi Curtis pearlymussel X

Epioblasma triquetra Snuffbox X

Epioblasma turgidula Turgid blossom X

Fusconaia ebena Ebonyshell X

Fusconaia flava Wabash pigtoe X

Fusconaia ozarkensis Ozark pigtoe X

Fusconaia subrotunda Long-solid X

Lampsilis abrupta Pink mucket X

Lampsilis cardium Pocketbook X

Lampsilis hydiana Louisiana fatmucket X

Lampsilis ornata Southern pocketbook X

Lampsilis powelli Arkansas fatmucket X

Lampsilis rafinesqueana Neosho mucket X

Lampsilis reeveiana Arkansas broken-ray X X

Lampsilis satura Sandbank pocketbook X

Lampsilis siliquoidea Fatmucket X

Lampsilis streckeri Speckled pocketbook X

Lampsilis teres Yellow sandshell X

Lasmigona complanata White heelsplitter X

Lasmigona costata Fluted-shell X

Leptodea fragilis Fragile heelsplitter X

Leptodea leptodon Scaleshell X

Ligumia recta Black sandshell X

Ligumia subrostrata Pondmussel X

Megalonaias nervosa Washboard X

Obliquaria reflexa Threehorn wartyback X

Obovaria jacksoniana Southern hickorynut X

Obovaria olivaria Hickorynut X

Plectomerus dombeyanus Bankclimber X

Plethobasus cyphyus Sheepnose X

Pleurobema coccineum Round pigtoe X

Pleurobema pyramidatum Pyramid pigtoe X

Potamilus alatus Pink heelsplitter X

Potamilus capax Fat pocketbook X

Potamilus ohiensis Pink papershell X

Potamilus purpuratus Bleufer X

Ptychobranchus occidentalis Ouachita kidneyshell X

Pyganodon grandis Giant floater X

Quadrula apiculata Southern mapleleaf X

Quadrula cylindrica Rabbitsfoot X

Quadrula fragosa Winged mapleleaf X

Quadrula metanevra Monkeyface X

Quadrula nodulata Wartyback X

(continued)

173
Table 2.27—Mussel species in the aquatic study area ranked as endangered, threatened, of special concern,

or currently stable by the American Fisheries Societya

 (continued)

Special Currently

Species Common name Endangered Threatened concern stable

Quadrula pustulosa Pimpleback X

Quadrula quadrula Mapleleaf X

Simpsonaias ambigua Salamander mussel X

Strophitus undulatus Squawfoot X

Toxolasma lividus Purple lilliput X

Toxolasma parvus Lilliput X

Toxolasma texasensis Texas lilliput X

Tritogonia verrucosa Pistolgrip X

Truncilla donaciformis Fawnsfoot X

Truncilla truncata Deertoe X

Uniomerus declivus Tapered pondhorn X

Uniomerus tetralasmus Pondhorn X

Utterbackia imbecillis Paper pondshell X

Venustaconcha ellipsiformis Ellipse X

Venustaconcha pleasi Bleedingtooth mussel X

Villosa arkansasensis Ouachita creekshell X

Villosa iris Rainbow X

Villosa lienosa Little spectaclecase X

Total 8 10 17 41

a Rankings may differ from those assigned by the USDI Fish and Wildlife Service.

Source: Williams and others (1989a).

174
Table 2.28—Crayfish species in the aquatic study area ranked by the American Fisheries Society as endangered,

threatened, of special concern, or currently stablea

Special Currently

Species Common name Endangered Threatened concern stable

Cambarellus puer Cajun dwarf X

Cambarellus shufeldtii Shufeldt’s dwarf X

Cambarus aculabrum X

Cambarus causeyi X

Cambarus diogenes Devil crayfish X

Cambarus hubbsi Hubb’s crayfish X

Cambarus hubrichti Salem Cave crayfish X

Cambarus maculatus Freckled crayfish X

Cambarus setosus Bristly Cave crayfish X

Cambarus subterraneus X

Cambarus tartarus X

Cambarus zophonastes X

Fallicambarus caesius X

Fallicambarus fodiens Digger crayfish X

Fallicambarus harpi Harp’s crayfish X

Fallicambarus jeanae X

Fallicambarus strawni X

Faxonella blairi X

Faxonella clypeata Shield crayfish X

Orconectes acares X

Orconectes eupunctus Coldwater crayfish X

Orconectes harrisonii Belted crayfish X

Orconectes hylas Woodland crayfish X

Orconectes immunis Papershell crayfish X

Orconectes leptogonopodus X

Orconectes longidigitus Longpincered crayfish X

Orconectes luteus Golden crayfish X

Orconectes macrus Neosho midget crayfish X

Orconectes marchandi Mammoth Spring crayfish X

Orconectes medius Saddlebacked crayfish X

Orconectes meeki brevis X

Orconectes meeki meeki Meek’s crayfish X

Orconectes menae X

Orconectes nais X

Orconectes nana X

Orconectes neglectus chaenodactylus X

Orconectes neglectus neglectus Ringed crayfish X

Orconectes ozarkae Ozark crayfish X

Orconectes palmeri longimanus X

Orconectes palmeri palmeri Grey-speckled crayfish X

Orconectes peruncus Big Creek crayfish X

Orconectes punctimanus Spothanded crayfish X

Orconectes quadruncus St. Francis River crayfish X

Orconectes saxatilis X

Orconectes virilis Northern crayfish X

Orconectes williamsi William’s crayfish X

Procambarus acutus White River crayfish X

Procambarus clarkii Red swamp crayfish X

Procambarus curdi X

Procambarus gracilis Grassland crayfish X

Procambarus liberorum X

Procambarus ouachitae X

Procambarus parasimulans X

Procambarus regalis X

Procambarus reimeri X

Procambarus simulans X

Procambarus tenuis X

Procambarus tulanei X

Procambarus viaeviridis Vernal crayfish X

Total 8 5 10 36

a Rankings may differ from those assigned by the USDI Fish and Wildlife Service; common names provided if known.

Source: Taylor and others (1996).

175
Aquatic Habitats

Question 2.11: What is the status of the aquatic

habitats within the Assessment area?

The presence and abundance of aquatic organisms

(e.g., fish and aquatic invertebrates) and features of the

physical habitat (e.g., stream size) are primary tools to

assess the quality of aquatic habitats (Karr and others

1986, Plafkin and others 1989, Dolloff and others 1993).

To examine the status of aquatic habitats, a series of

measurements and samples usually is taken at a specific

site or series of sites within a stream or river. Such

specific information is unavailable for large portions of

the Assessment area.

Investigations of habitat quality are usually limited by

both the area investigated and the length of the study

and may differ in primary objectives (e.g., water

pollution detection versus suitability of habitat for a

fishery). Recently initiated efforts by the Geological

Survey’s NAWQA program are designed to provide a

consistent description of the features of physical

habitats as part of an evaluation of water quality. The

focus of the NAWQA program within the Assessment

area to date has been the Ozark Plateaus, but that study

was released after writing ceased for this report and is

not included here (Femmer 1997). Large-scale analyses

in Arkansas have linked water quality and other physical

variables to overall patterns of fish distribution (Rohm

and others 1987, Matthews and Robison 1988,

Matthews and others 1992). In previous sections of this

chapter, the Aquatic Team evaluated the diversity of

selected groups of aquatic organisms (i.e., fishes,

mussels, crayfishes, stoneflies, and caddisflies) across

the study area. However, no comparable information

base exists that can be used to directly examine the

status of aquatic habitats across the Ozark-Ouachita

Highlands (see “Surface Water Quality (Streams)” and

“Surface Water Quality (Lakes)” in this chapter,

“Outstanding Resource Waters” in Chapter 4, and other

studies referenced above).

The Aquatic Team used the number of stream types

within hydrologic units to examine the large-scale

patterns of diversity of aquatic habitats across the

Assessment area. Each “stream type” is a unique

combination of three landscape-scale attributes:

(1) hydrologic unit, (2) ecological section, and (3) stream

size. Each of these attributes may include habitat

conditions that influence the number and kinds of

aquatic organisms found across the Assessment area.

For example, endemic and other native aquatic species

are associated with specific drainage systems or, as

termed in this report, hydrologic units. Likewise, sections within hydrologic units often have different stream

water chemistry and geomorphologies (i.e., differing

conditions that arise from the distinctive geological

evolution of each section’s landscape, riparian zones,

and water bodies). Consequently, streams show differences in the makeup of their aquatic communities.

Finally, different stream sizes within different ecological

sections within a hydrologic unit generally support

different numbers of aquatic species. When combined,

these three attributes—hydrologic unit, ecological

section, and stream size—provide a description of largescale differences among running-water habitats within

and among hydrologic units. For example, a first-order

stream (i.e., smallest headwater) in the Ozark Highlands

of the Upper White River hydrologic unit represents a

distinctly different stream type than a first-order stream

in the West Gulf Coastal Plain section of the Upper

Ouachita River hydrologic unit. Likewise, a small

stream is expected to differ in physical habitat and

faunal composition from a medium-sized river within the

same province and hydrologic unit.

 Key Findings

 1. Over half of the hydrologic units in the Assessment

area have 10 or more stream types per hydrologic

unit (average = 8.7 stream types per hydrologic unit;

range of 5 to 15 per hydrologic unit), and no hydrologic unit has fewer than 5 stream types.

 2. Primary levels of stream type diversity (11 to 15

stream types per hydrologic unit) are located mostly

in the southern half of the Assessment area;

secondary levels (10 stream types per hydrologic

unit) are located in hydrologic units along the

periphery of the Assessment area.

 3. Native fish species richness is associated significantly and positively with the number of different

stream types in hydrologic units.

176
 4. Numbers of endemic fish species and stream types

are not associated among hydrologic units.

 5. Hydrologic units with primary and secondary levels

of stream type diversity and native fish species

richness may be considered of particular significance in maintaining present and future aquatic

biodiversity within the Ozark-Ouachita Highlands.

 6. Available analyses indicate that strong associations

exist between environmental variables (e.g., water

quality, geology, substrate) and the distribution of

fishes over much of the Assessment area, and any

pervasive alteration of existing habitat conditions

likely would affect the composition and distribution

of the fish fauna.

Data Sources and Methods of Analysis

The Aquatic Team calculated stream type diversity

by summing the combinations of stream orders and

ecological sections for each hydrologic unit within the

Assessment area, following Warren and others (1997).

The team recognized 50 hydrologic units (watersheds)

as occurring partly or wholly within the Assessment

area. As reported in the “Diversity of Fishes” subsection

of this chapter, the team further subdivided 32 of these

watersheds by digitally overlaying ecological sections

(Keys and others 1995) onto each hydrologic unit to

form two or more ecological-hydrologic units (fig. 2.17).

Twenty-five hydrologic units include lands and

waters outside the Assessment area. For these units,

stream type diversity includes stream types not necessarily within the Highlands. The team used the EPA’s

River File version 3 (RF3), to determine stream size.

The Aquatic Team recognized stream sizes as ranging

from first order (smallest streams) to seventh order

(largest streams), where order was determined following Strahler (1964). The team then delineated three

levels of stream type diversity among hydrologic units:

primary, secondary, and tertiary. Primary levels were

assigned to the 13 units with highest values; secondary

levels were assigned to the next highest 13 units; and

tertiary levels, to the remaining 24 units. Hence, primary

levels approximate values in the fourth quartile (top 25

percent); secondary levels (second 25 percent), values

in the third quartile; and tertiary levels, values in the first

and second quartiles (bottom 50 percent).

The Aquatic Team used two approaches to examine

the association of stream type diversity with elements of

the aquatic fauna. First, using data synthesized for this

report, the team examined stream type diversity for

association with richness of native fish species and

richness of endemic fish species in hydrologic units.

Second, the team summarized the work of Matthews and

Robison (1988) and Matthews and others (1992) on largescale physical habitat attributes and distribution of fishes.

Fish species richness is the total number of native

fishes recorded as present in a hydrologic unit; richness

of endemic fish species is the number of fishes that are

endemic to the Assessment area and occur exclusively

in a particular hydrologic unit (see “Diversity of Fishes”

in this chapter). The Aquatic Team used a rank correlation procedure (known in statistics as Kendall’s tau beta

coefficient) to test the association between stream type

diversity, richness of native fish species, and richness of

endemic species among hydrologic units.

In this report, stream type diversity accounts only for

flowing surface waters and the presence of a unique

combination of ecological section and stream size within

a hydrologic unit. Some hydrologic units certainly

contain other unique habitat types such as springs,

caves, wetlands, or natural lakes that are not accounted

for by stream type diversity. Hydrologic units also may

have impoundments (e.g., reservoirs) that have altered

the habitats available to aquatic organisms. The gains or

losses of habitat diversity in these inundated areas are

not reflected in this report as contributing to or lessening

the number of stream types within a hydrologic unit.

Likewise, the measure of stream type diversity in this

report does not account for the spatial extent of a

particular stream type within a hydrologic unit. The

Aquatic Team accounted only for the presence of

certain stream types within a unit.

Patterns and Trends

Stream type diversity is not evenly distributed across

the Assessment area (table 2.29). The average stream

type diversity was 8.7 stream types per hydrologic unit

(two standard errors = 0.86), and the range was 5 to 15

different stream types per hydrologic unit. Thirty-eight

of 50 hydrologic units had at least 6 stream types; no

hydrologic unit had fewer than 5 stream types. Half of

177
Table 2.29—Stream type diversity and numbers of native and endemic fish species in the

aquatic study area watersheds

River basin Watershed code Stream type Native fish Endemic fish

Watershed name (HUC) diversitya species species

Osage River Basin

H.S. Truman Reservoir 10290105 10 63 2

Sac 10290106 10 62 7

Pomme de Terre 10290107 5 61 3

South Grand 10290108 10 40 0

Lake of the Ozarks 10290109 6 65 4

Niangua 10290110 5 67 7

Lower Osage 10290111 11 85 6

Gasconade River Basin

Upper Gasconade 10290201 6 61 6

Big Piney 10290202 5 61 6

Lower Gasconade 10290203 10 86 6

Meramec River Basin

Meramec 07140102 9 96 4

Bourbeuse 07140103 10 65 3

Big 07140104 11 66 4

Upper St. Francis River Basin

Upper St. Francis 08020202 5 94 6

Neosho-Illinois River Basin

Lake O’ the Cherokees 11070206 10 90 3

Spring 11070207 10 88 2

Elk 11070208 6 57 4

Lower Neosho 11070209 15 98 3

Illinois 11110103 9 106 4

Arkansas River Basin

Dirty-Greenleaf 11110102 15 100 3

Robert S. Kerr Reservoir 11110104 11 112 5

Poteau 11110105 6 95 2

Frog-Mulberry 11110201 11 95 3

Dardanelle Reservoir 11110202 11 92 3

Conway- Pt. Remove 11110203 5 77 0

Petit Jean 11110204 5 73 1

Cadron 11110205 5 67 1

Fourche La Fave 11110206 5 69 3

Lower Ark-Maumelle 11110207 12 90 0

Kiamichi-Little River Basin

Kiamichi 11140105 10 87 2

Upper Little 11140107 8 103 4

Mountain Fork 11140108 9 101 5

Lower Little 11140109 11 118 5

Ouachita-Saline River Basin

Ouachita Hdwaters 08040101 5 75 6

Upper Ouachita 08040102 10 113 5

Little Missouri 08040103 10 94 4

Upper Saline 08040203 10 96 2

Upper White River Basin

Beaver Reservoir 11010001 11 82 13

James 11010002 6 63 12

Bull Shoals Lake 11010003 6 79 11

Middle White 11010004 15 112 11

Buffalo 11010005 9 54 10

North Fork White 11010006 6 74 11

Little Red 11010014 15 90 8

Upper Black River Basin

Upper Black 11010007 10 111 5

Current 11010008 10 116 9

Lower Black 11010009 8 98 5

Spring 11010010 5 114 8

Eleven Point 11010011 5 71 7

Strawberry 11010012 5 89 4

HUC = hydrologic unit code.

a Stream type diversity is the sum of the stream order occurence for each ecological section present in the watershed.

Source: see “Data Sources and Methods of Analysis” of this section.

178
the hydrologic units had stream type diversity values of

10 or more.

Primary levels of stream type diversity (11 to 15

stream types) were located mostly in the middle of the

aquatic study area (fig. 2.35). Hydrologic units straddling two ecological sections tended to show primary

levels of stream type diversity. For example, most

hydrologic units containing parts of both the Arkansas

Valley and Boston Mountains or Ozark Highlands and

Boston Mountains showed primary levels (i.e., Lower

Neosho, Dirty-Greenleaf, Robert S. Kerr Reservoir,

Beaver Reservoir, Frog-Mulberry, Dardanelle Reservoir,

Little Red, and Middle White units). Several other units

along the periphery of the Assessment area also

showed primary levels of stream type diversity: the

Lower Little, Lower Arkansas-Maumelle, and Upper

Black units. In the north, the Lower Osage (Osage

River drainage) and the Big (Meramec River drainage)

units also showed primary levels.

Secondary levels of stream type diversity (10 stream

types per hydrologic unit) occur particularly along the

periphery of the Assessment area (fig. 2.35). This

pattern was most apparent along the northwestern,

western, and southern borders of the aquatic study area,

where almost all units showed at least secondary levels

of stream type diversity.

Tertiary levels of stream type diversity (fewer than

10 stream types per hydrologic unit) were concentrated

Figure 2.35—Stream type diversity by watershed.

Levels of stream type diversity

Primary

Secondary

Tertiary

Oklahoma

Arkansas

Missouri

179
in hydrologic units primarily in the Ozark Highlands and

in those units draining into the Arkansas River (fig.

2.35). These hydrologic units typically had values of five

or six stream types.

Native fish species richness was associated with the

number of stream types in hydrologic units. The correlation of the rank of native fish species richness and

stream types of hydrologic units was significant and

positive (Kendall’s tau beta coefficient = 0.29, P <

0.0066). The rank of endemic fish species richness and

stream types within hydrologic units was not correlated

(Kendall’s tau beta coefficient = -0.01, P < 0.9474).

The association of native fish species richness with

stream type diversity is not unexpected. Increasing

heterogeneity of habitats from small to large spatial

scales often is associated with increasing levels of

faunal diversity (Schluter and Ricklefs 1993). Those

hydrologic units with primary and secondary levels of

stream type diversity and native fish species richness

may be considered of particular significance in maintaining present and future aquatic biodiversity within the

Ozark-Ouachita Highlands.

In their analyses, Matthews and Robison (1988) and

Matthews and others (1992) included the portion of the

Assessment area within the State of Arkansas. Matthews

and Robison (1988) examined the association of fish

distribution in 101 drainage units of Arkansas by focusing

on three groups of environmental variables: (1) geographical (elevation, longitude, latitude); (2) meteorological (annual precipitation, frost-free days, mean January

temperature, mean July temperature); and (3) local or

site-specific (turbidity, substrate, width, geology). In an

extension of that work, Matthews and others (1992)

also examined the association of fish distribution in

Arkansas by using 11-year averages of Arkansas

Department of Pollution Control and Ecology and

Geological Survey water quality data (Petersen 1988)

for 70 of the original 101 drainage units in Arkansas.

These water quality data included oxygen, pH, conductivity, alkalinity, total hardness, magnesium, sulfate,

chloride, total dissolved solids, total phosphorus, nitrate,

ammonia, turbidity, and biochemical oxygen demand.

Hence, their work and this summary of their work are

directly applicable only to that portion of the Assessment area in Arkansas.

Matthews and Robison (1988) found that values for

10 of 11 geographic, meteorological, and local variables

were associated with the presence or absence of fish

species in upland (highland habitats within the Arkansas

Assessment area) versus lowland habitats in Arkansas.

In constructing predictive models, they reported that a

variety of combinations of these variables provided a

good basis for predicting the presence or absence of

fishes associated with specific drainage units. In

particular, local factors (turbidity, substrate, width, and

geology) and one strongly defining meteorological factor

(mean January temperature) were most predictive of

the presence or absence of a fish species.

Matthews and others (1992) found significant

associations between fish distributions and general

water quality patterns. They reported specific associations between water quality variables and fishes of the

Southern Ozark and Ouachita Mountain Fish Faunal

and Ozark Upland Fish Faunal Regions (which together encompass most of the Assessment area in

Arkansas). Fishes characteristics of the Assessment

area were associated with lower total dissolved solids,

hardness, chloride, conductivity, ammonia, and biochemical oxygen demand, and with higher dissolved

oxygen, pH, alkalinity, and magnesium. Matthews and

others (1992) emphasized that environmental variables

such as water quality parameters are likely to operate

in concert with each other and not as isolated single

variables. They further emphasized that evidence of a

high degree of association between fishes and environmental variables in the Assessment area should be

considered carefully before projects are undertaken

that may instigate pervasive alteration of existing

aquatic habitat conditions.

Implications and Opportunities

The method of addressing aquatic habitats presented here provides only a small portion of the

information necessary to understand aquatic ecosystems. However, combining watersheds, size classes,

and ecological units is a promising method for classifying aquatic habitats.

180
 Key Findings

 1. Of the almost 3 million acres of riparian areas

identified within the Assessment area, approximately 57 percent are forested, 37 percent are

agricultural, 2 percent are urban, and 4 percent

are classified as “other.”

 2. The Upper Saline watershed has the greatest

percentage (87.4 percent) and the South Grand

watershed has the lowest percentage (14.9 percent) of forested riparian areas in the study area.

 3. National forests generally have highly forested

riparian areas (86 to 93 percent).

Data Sources and Methods of Analysis

Two GIS data layers were required for this section.

The stream GIS layer is from the EPA’s RF3 data base,

and the land cover GIS layer is from the Geological

Survey’s Geographic Information Retrieval and Analysis

System (GIRAS). The RF3 data layer was derived from

1:100,000 maps. This data layer has not been released

by the EPA for general public use and does contain

some mapping errors. The GIRAS data were at the

1:250,000 scale. Unfortunately, the GIRAS data set was

developed in the late 1970’s and early 1980’s. While

probably not representative of the latest land cover in

the Assessment area, it is the best data base currently

available.

The Aquatic Team identified riparian areas by

buffering 100 ft on each side of the streams in the RF3

data base. The team then intersected this buffered area

with the land use data base and executed queries about

the resulting data set by watershed and national forest

ownership layers. Empty values resulting from the

intersecting process were ignored.

Patterns and Trends

The Aquatic Team identified 2,966,192 acres of

riparian areas within the Assessment area; approximately 57 percent of the acres are forested, 37 percent

are agricultural, 2 percent was urban, and 4 percent are

classified as “other” (table 2.30).

Riparian Areas

Question 2.12: What are the extent and

vegetative composition of riparian areas within

the Assessment area?

A riparian area is a zone immediately adjacent to a

river, stream, lake, or pond. A healthy stream riparian

area, one with stable stream banks with little or no

erosion, sustains many ecological functions (Gregory

and others 1991). Healthy riparian areas will withstand

seasonal flooding and support the aquatic system by

contributing organic matter (e.g., fallen trees, leaves) for

the food chain. Such areas also provide structures for

habitats (e.g., undercut banks, large woody debris, and

rootwads). In addition, riparian areas provide essential

shade and stream temperature regulation as well as

cover and travel corridors for wildlife. Finally, they

serve as filters to reduce erosion and sediment inputs

from upland erosion that may occur outside the riparian

area (Barling and Moore 1994). All streams need wellestablished riparian areas of natural vegetation to attain

and maintain their biological integrity.

Land uses within riparian areas provide insight into

the condition of the riparian and aquatic systems.

Watersheds or river basins with large percentages of

forested or undisturbed riparian areas tend to be more

stable in terms of overall water quality and biological

integrity. Agricultural, urban, and residential riparian

areas are at a greater risk of incurring adverse effects

from human activities. Assessments of riparian areas

covering large areas are generally not available. With

the advent of remote sensing and Geographic Information System (GIS) technologies, it is now possible to

develop inventories of riparian area conditions over

large geographical areas (Hunsaker and Levine 1995,

Steedman 1988) such as the Highlands.

181
Table 2.30—Acres in riparian areas and predominant land uses within riparian zones of Assessment area watersheds

River basin Watershed code Riparian

Watershed name (HUC) area Forest Agriculture Urban Other

Acres Acres % Acres % Acres % Acres %

Osage River Basin

H.S. Truman Reservoira 10290105 42,950 17,779 41.4 24,038 56.0 190 0.4 943 2.2

Saca 10290106 67,173 20,345 30.3 43,316 64.5 1,053 1.6 2,459 3.7

Pomme de Terre 10290107 33,759 13,443 39.8 18,893 56.0 735 2.2 688 2.0

South Grand 10290108 81,843 12,176 14.9 66,662 81.5 699 0.9 2,307 2.8

Lake of the Ozarks 10290109 67,697 41,932 61.9 17,772 26.3 1,261 1.9 6,732 9.9

Niangua 10290110 45,317 26,099 57.6 17,884 39.5 369 0.8 964 2.1

Lower Osage 10290111 38,762 17,343 44.7 19,001 49.0 141 0.4 2,276 5.9

Gasconade River Basin

Upper Gasconade 10290201 74,499 37,876 50.8 35,670 47.9 907 1.2 46 0.1

Big Piney 10290202 31,490 18,708 59.4 12,174 38.7 576 1.8 32 0.1

Lower Gasconade 10290203 44,191 25,913 58.6 17,857 40.4 237 0.5 183 0.4

Meramec River Basin

Meramec 07140102 89,491 55,196 61.7 29,990 33.5 2,462 2.8 1,843 2.1

Bourbeuse 07140103 32,450 14,469 44.6 17,301 53.3 284 0.9 396 1.2

Big 07140104 41,441 24,095 58.1 14,693 35.5 909 2.2 1,743 4.2

Upper St. Francis River Basin

Upper St. Francis 08020202 54,052 30,688 56.8 20,823 38.5 297 0.5 2,244 4.2

Neosho-Illinois River Basin

Lake O’ the Cherokeesa 11070206 25,258 7,782 30.8 13,612 53.9 1,059 4.2 2,806 11.1

Springa 11070207 59,363 10,939 18.4 45,168 76.1 1,229 2.1 2,028 3.4

Elka 11070208 23,718 10,058 42.4 12,358 52.1 794 3.3 509 2.1

Lower Neoshoa 11070209 65,775 24,777 37.7 34,386 52.3 897 1.4 5,716 8.7

Illinois 11110103 62,643 27,856 44.5 31,138 49.7 2,289 3.7 1,360 2.2

Arkansas River Basin

Dirty-Greenleaf 11110102 32,767 10,531 32.1 18,711 57.1 980 3.0 2,545 7.8

Robert S. Kerr Reservoir 11110104 74,885 34,335 45.8 30,537 40.8 1,711 2.3 8,303 11.1

Poteau 11110105 93,900 53,927 57.4 36,472 38.8 1,082 1.2 2,419 2.6

Frog-Mulberry 11110201 48,495 29,998 61.9 14,667 30.2 982 2.0 2,847 5.9

Dardanelle Reservoir 11110202 76,594 47,879 62.5 22,782 29.7 1,109 1.4 4,824 6.3

Conway- Pt. Remove 11110203 50,867 24,512 48.2 19,878 39.1 977 1.9 5,499 10.8

Petit Jean 11110204 41,429 23,608 57.0 16,608 40.1 279 0.7 934 2.3

Cadron 11110205 37,256 20,324 54.6 16,379 44.0 218 0.6 335 0.9

Fourche La Fave 11110206 51,225 38,911 76.0 10,895 21.3 113 0.2 1,307 2.6

Lower Ark-Maumelle 11110207 55,560 27,281 49.1 17,468 31.4 3,612 6.5 7,199 13.0

Kiamichi-Little River River Basin

Kiamichi 11140105 71,546 48,960 68.4 19,629 27.4 594 0.8 2,363 3.3

Upper Littlea 11140107 42,871 34,795 81.2 6,471 15.1 368 0.9 1,238 2.9

Mountain Forka 11140108 32,296 26,777 82.9 3,154 9.8 223 0.7 2,142 6.6

Lower Littlea 11140109 73,601 54,667 74.3 15,017 20.4 709 1.0 3,208 4.4

Ouachita-Saline River Basin

Ouachita Headwaters 08040101 66,307 48,287 72.8 10,159 15.3 1,740 2.6 6,121 9.2

Upper Ouachita 08040102 88,334 70,565 79.9 13,446 15.2 1,253 1.4 3,070 3.5

Little Missouri 08040103 91,523 61,959 67.7 20,500 22.4 6,955 7.6 2,108 2.3

Upper Saline 08040203 86,278 75,390 87.4 7,836 9.1 1,150 1.3 1,902 2.2

Upper White River Basin

Beaver Reservoir 11010001 84,621 48,970 57.9 25,467 30.1 1,911 2.3 8,272 9.8

James 11010002 52,889 19,143 36.2 31,802 60.1 1,303 2.5 642 1.2

Bull Shoals Lake 11010003 115,836 69,459 60.0 32,143 27.7 1,606 1.4 12,628 10.9

Middle White 11010004 59,994 38,409 64.0 17,186 28.6 465 0.8 3,935 6.6

Buffalo 11010005 50,547 40,049 79.2 10,004 19.8 74 0.1 420 0.8

North Fork White 11010006 74,760 47,014 62.9 23,061 30.8 247 0.3 4,437 5.9

Little Red 11010014 79,921 52,446 65.6 19,275 24.1 1,189 1.5 7,011 8.8

Upper Black River Basin

Upper Black 11010007 80,174 48,414 60.4 30,176 37.6 900 1.1 683 0.9

Current 11010008 106,619 75,859 71.1 30,328 28.4 334 0.3 98 0.1

Lower Black 11010009 38,438 11,363 29.6 26,351 68.6 193 0.5 530 1.4

Spring 11010010 47,600 26,262 55.2 20,296 42.6 730 1.5 312 0.7

Eleven Point 11010011 46,996 28,565 60.8 18,274 38.9 107 0.2 49 0.1

Strawberry 11010012 30,191 15,154 50.2 14,617 48.4 186 0.6 234 0.8

Total 2,966,192 1,691,287 57.0 1,092,325 37.0 49,688 2.0 132,890 4.0

HUC = hydrologic unit code.

a Streams and corresponding riparian areas were mapped at a lower density in the River File 3 data base for portions of these watersheds.

182
Figure 2.36 displays the percent of forested riparian

area for the watersheds within the aquatic study area.

Riparian forest cover was separated into three catego

Figure 2.36 displays the percent of forested riparian

area for the watersheds within the aquatic study area.

Riparian forest cover was separated into three categories: ries: less than 32 percent, 33 to 68 percent, and

greater than 68 percent. Of the nine watersheds with

the highest percent of forested riparian area, seven are

located in the Ouachita Mountains. The Upper Saline

watershed has the greatest percentage of forested

riparian area (87.4 percent).

Of the six watersheds with the lowest percentage of

forested riparian area, all are located on the outlying

watersheds. Most are in the northwestern portion of the

Assessment area where there is a strong influence of

prairie. The South Grand watershed (with only 14.9

percent) has the lowest percentage of forested riparian

cover.

The riparian areas of the Ozark-St. Francis, Ouachita,

and Mark Twain National Forests are 93, 92, and 86

percent forested, respectively (table 2.31).

Figure 2.36—Percent of forested riparian areas by Assessment area watershed.

Forested riparian area

< 32%

33–68%

> 69%

Oklahoma

Arkansas

Missouri

183
Generally, land uses in riparian areas parallel land

uses within their respective watersheds. The outlying

watersheds typically have greater percentages of

agricultural and “other” use categories. Watersheds

within the mountainous areas typically have greater

percentages of forested riparian area.

Implications and Opportunities

As better data bases about land uses become available, this type of analysis will become more meaningful.

However, it is clear that some watersheds in the

Assessment area have very low percentages of forest

cover in riparian areas, which may signal higher potential for problems associated with unhealthy riparian

areas if forest is the primary indigenous vegetation.

The national forests within the Assessment area

conserve large areas of forested riparian areas. The

opportunity exists for the Forest Service (and other

public land management agencies) to continue sound

management of these areas and to promote the restoration, wise use, and continued protection of riparian areas.

Wetlands

Question 2.13: What are the extent and

composition of wetlands within the Assessment

area?

There are several definitions for wetlands, and most

of them share similar meanings. In most definitions, a

wetland area is required to (1) be periodically flooded,

(2) have plants that are adapted to growing in wet

conditions, and (3) have soils that developed under wet

conditions. Despite these similarities, no single conclusive definition exists for wetlands. Following are examples of some of the current definitions for wetlands:

• “Wetlands are those areas that are inundated or

saturated by surface or ground water at a frequency

and duration sufficient to support, and that under

normal circumstances do support, a prevalence of

vegetation typically adapted for life in saturated soil

conditions. Wetlands generally include swamps,

marshes, bogs, and similar areas” (EPA, 40 CFR

230.3, December 24, 1980; and CE, 33 CFR 328.3,

November 13, 1986).

• The Food Security Act of 1985 (as amended)

contains a similar definition of wetlands that also

emphasizes hydrology, the presence of plants that are

adapted for life in water-saturated soils, and saturated soil conditions.

• The Fish and Wildlife Service’s definition of wetlands

includes both vegetated and nonvegetated wetlands,

recognizing that some types of wetlands lack vegetation (for example, mud flats, sand flats, rocky shores,

gravel beaches, and sand bars).

Wetlands are important because they store floodwaters, reduce flood peaks, filter sediments and nutrients

from runoff, and provide habitats for wetlands-dependent plants and animals. The Assessment area has a

variety of wetlands including (1) bottomland hardwood

wetlands, (2) swamps, (3) fens (wet alkaline areas with

peaty or other organic rooting medium), (4) wet prairies,

and (5) freshwater marshes. Bottom land hardwood

wetlands are seasonally flooded areas near streams and

rivers where pin oak, silver maple, cottonwood, black

willow, and river birch are the dominant vegetation;

flooding is frequent; and the soils are poorly drained.

Swamps consist of depressions, oxbow ponds, and

backwater sloughs along stream and river floodplains

where bald cypress and/or tupelo gum are the dominant

trees; flooding is frequent; and the soils are very poorly

drained. Fens occur on side slopes of hills in narrow

Table 2.31—Acres in riparian areas and the predominant land uses within those riparian

areas, by national forest

National forest Forest Agriculture Urban Other

Acres % Acres % Acres % Acres %

Ozark 75,453 93 3,765 5 0 0 1,828 2

Ouachita 117,906 92 7,582 6 58 <1 2,596 2

Mark Twain 127,386 86 19,380 13 100 <1 738 2

184
are areas along floodplains of larger streams and rivers

where tall grasses and sedges are the dominant vegetation, flooding is frequent, and the soils are poorly

drained. Freshwater marshes are depressions along

rivers where cattails, bulrushes, and sedges are the

dominant forms of vegetation; flooding is frequent

during winter and spring; and the soils are very poorly

drained (Nelson 1987).

 Key Findings

 1. Since the 1780’s, wetland losses in Assessment

area States have ranged from 50 to greater than 75

percent (Dahl 1990).

 2. Most of the State Soil Geographic data base soilmap units that include hydric soils (soils that are

saturated, flooded, or ponded long enough during

the growing season to deplete the oxygen in the

upper part of the soil) are found along the Grand,

Sac, Black, White, Arkansas, Ouachita, and Little

Rivers. These areas are potential wetlands because

they have saturated soils, one of the essential

components of the designation “wetlands.”

 3. According to the State 305(b) inventory reports of

water quality, most of the wetlands in Arkansas,

Missouri, and Oklahoma have been converted to

agricultural production during historic times.

 4. Camden and Taney Counties, MO, and Pulaski

County, AR, had the most Clean Water Act 404

permits issued from 1988 through 1996. If the

number of permits issued indicates activity in

wetlands and other water bodies, the Osage, Upper

White, and Arkansas River Basins had the most

activity from 1988 through 1996.

Data Sources and Methods of Analysis

The State Soil Geographic (STATSGO) data base for

Arkansas, Missouri, and Oklahoma provided the data

needed to locate potential wetland areas in the study

area. Dahl’s (1990) study of wetland losses provided an

estimate of the amount of wetlands lost in the Assessment area up to 1990. The State 305(b) water quality

reports for Arkansas, Missouri, and Oklahoma provided

information on the reasons for wetlands loss. The

Aquatic Team used data compiled by the Environmental

Working Group (1997) on the numbers of nationwide

404 permits issued by the U.S. Army Corps of Engineers to determine where most of the activities have

occurred in wetlands in the Assessment area. Nelson

(1987) provided locations and descriptions of some of

the important wetlands in the Ozark Highlands section.

The Fish and Wildlife Service’s Regional Wetlands

Concept Plan (1992) provided information on wetlands

in Arkansas.

Patterns and Trends

Most of the STATSGO map units that include hydric

soils (soils that are saturated, flooded, or ponded long

enough during the growing season to deplete the oxygen

in the upper part of the soil) are found within the Osage,

Upper Black, Meramec, Gasconade, and OuachitaSaline River Basins and the following noncontiguous

units: Spring (Neosho-Illinois River Basin), Little Red,

Lower Arkansas-Maumelle, and Lower Little (fig.

2.37). Table 2.32 lists some of the important wetlands in

the Assessment counties (many are just outside the

Highlands per se).

The U.S. Army Corps of Engineers issues permits

for activities that require dredging and any filling of

material into the waters of the United States. The

permits are issued under section 404 of the Clean

Water Act (see Chapter 3 of this report). The term

“waters of the United States” includes rivers, lakes,

streams, intermittent streams, mudflats, and wetlands

(33 CFR 328.3, 1995). General permits are issued at a

national or regional level and are designed to regulate

activities that have minimal effects on water resources.

Larger and more complex projects often require

individual permits that entail more oversight by the

Corps of Engineers. The number of permits issued can

be used to get a general indication of the activity that is

occurring in wetlands and other water bodies. Camden

and Taney Counties, MO, and Pulaski County, AR, had

the most permits issued from 1988 through 1996 in

Assessment area counties. Assuming that the number

of permits issued indicates activity in wetlands and

other water bodies, then the Osage, Upper White, and

Arkansas River Basins had the most activity. Table 2.33

shows the numbers of 404 permits denied, issued, and

withdrawn by the Corps of Engineers in Assessment

area counties from 1988 through 1996.

185
Wetland losses from the 1780’s to the 1980’s range

from 50 to greater than 75 percent in present-day States

of the Assessment area (Dahl 1990). According to the

Arkansas Statewide Comprehensive Outdoor Recreation Plan for 1995 (Turner 1995), Arkansas continues

to experience significant wetland loss. Turner (1995)

cites (1) drainage and flood protection;

(2) dredging and stream channelization; (3) conversion

from forested wetlands to scrub-scrub, emergent, or

open-water wetlands; (4) alteration of drainage patterns; (5) construction of dikes and levees; and

(6) discharge of pollutants as threats to the remaining

forested wetlands of Arkansas. Most of the wetlands

lost in Arkansas have been converted to agriculture.

Johnston (1994) cites a Fish and Wildlife Service study

that estimates that 54 percent of the wetlands lost

between the 1950’s and 1970’s were forested wetlands.

From the mid-1970’s to the 1980’s, 95 percent of all

wetlands lost were forested wetlands. According to the

Fish and Wildlife Service, Arkansas was one of the

States with the largest losses of forested wetlands.

Conversion to agricultural production, clearing of

hardwood forests, railroad construction, federally

encouraged draining and filling of wetlands, river and

stream channelization projects, extensive Federal and

private levee development, and dams for flood control

Figure 2.37—Areas of hydric soils in and adjacent to the Ozark-Ouachita Highlands.

Oklahoma

Hydric soils

Arkansas

Missouri

186
Table 2.32—Some important wetlands in Assessment area counties

Wetland County and State

Mingo National Wildlife Refugea Wayne and Stoddard, MO

Fiddler Pond, Irish Wilderness Oregon, MO

Peck Ranch Sinkhole Pond Natural Area Carter, MO

Tupelo Gum Pond Natural Area Carter, MO

Sunklands Natural Area Shannon, MO

Burr Oak Basin Natural Area Shannon, MO

Sand Ponds State Forest Butler, MO

Coonville Creek Natural Area St. Francois, MO

Hussman Fen Natural Area Shannon, MO

Sutton Creek Fen Shannon, MO

Medley Hollow Fen Shannon, MO

Coakley Hollow Fen Natural Area Camden, MO

Bennett Spring Hanging Fen Natural Area Dallas and Laclede, MO

Ruble Meadow Reynolds, MO

Grasshopper Hollow Natural Area Reynolds, MO

Raised Fen Reynolds, MO

Wash Creek Alder Bog Bollinger, MO

Big Buffalo Creek Marsh Natural Area Benton, MO

Mint Spring Natural Area Gasconade, MO

Cupola Pond Natural Area Ripley, MO

Allred Lake Natural Area Butler, MO

Lily Pond Natural Area Reynolds, MO

Garrison Fen Fulton, AR

Rock Creek Seep Fen Sharp, AR

Arnold Cemetery Road Pondberrya Jackson, AR

Centerville Pondberrya Jackson, AR

Otter Lakea Jackson, AR

Swifton Sand Pondsa Jackson, AR

Bald Knob White, AR

Bayou Des Arca White and Prairie, AR

Raft Creek Bottoms White and Prairie, AR

Wingmead Farmsa Prairie, AR

Seaton Dumpa Lonoke, AR

White Rivera Prairie, AR

Bayou Metoa Arkansas, Prairie, and Lonoke, AR

Fourche Bottomsa Pulaski, AR

Big Lake/Lorance Creeka Pulaski and Saline, AR

Pond Creek Bottomsa Sevier, AR

Buttermilk Spring Montgomery, AR

Meyer’s Creek Seep Garland, AR

Holla Bend National Wildlife Refuge Yell and Pope, AR

Dave Donaldson Black River Wildlife Management Area Clay and Randolph, AR

Cossatot National Wildlife Refugea Sevier, AR

Little River National Wildlife Refugea McCurtain, OK

a Outside the Highlands but within the aquatic study area.

Source: Nelson (1987), USDI FWS (1992).

187
Source: Environmental Working Group (1997).

General Individual

Permits permits permits Permits

County denied issued issued withdrawn

Missouri

Barry 0 54 9 0

Barton 0 9 1 0

Benton 9 66 26 9

Bollinger 0 9 11 0

Boone 0 66 3 2

Butler 1 77 20 3

Camden 21 274 198 31

Carter 0 15 3 1

Cedar 1 7 2 3

Christian 0 31 7 3

Cole 1 75 16 3

Crawford 0 43 10 3

Dade 0 15 1 0

Dallas 2 37 9 6

Dent 0 17 6 2

Douglas 2 13 9 2

Franklin 1 89 14 3

Gasconade 2 52 15 7

Greene 2 91 8 3

Henry 0 115 33 6

Hickory 0 33 2 2

Howell 0 19 0 0

Iron 0 40 7 0

Jasper 1 90 3 1

Jefferson 1 116 12 7

Laclede 0 16 5 1

Lawrence 0 41 4 6

McDonald 1 24 4 1

Madison 0 12 0 0

Maries 4 16 4 3

Miller 2 69 35 6

Morgan 13 109 69 8

Newton 0 41 1 0

Oregon 0 1 3 0

Osage 5 34 10 1

Ozark 0 30 7 0

Phelps 1 68 9 1

Polk 1 23 3 3

Pulaski 0 24 7 4

Reynolds 0 15 6 2

Ripley 0 84 16 1

Shannon 1 4 4 3

St. Clair 0 15 18 0

St. Francois 0 14 1 0

Ste. Genevieve 0 20 5 3

Stone 2 81 11 3

Taney 2 135 54 6

Texas 1 81 6 8

Washington 1 30 5 2

Wayne 1 80 9 4

Webster 0 16 4 2

Wright 1 11 3 0

Arkansas

Baxter 1 88 26 4

Benton 3 132 5 3

Table 2.33—Permits denied, general and individual permits issued, and permits withdrawn under Section 404 of the Clean Water

Act in Assessment area counties (1988–1996)

General Individual

Permits permits permits Permits

County denied issued issued withdrawn

Arkansas (continued)

Boone 0 24 3 1

Carroll 0 31 11 0

Clark 0 26 0 1

Cleburne 0 54 6 1

Conway 1 26 13 4

Crawford 0 70 13 3

Faulkner 1 53 10 4

Franklin 1 57 12 4

Fulton 0 25 2 0

Garland 0 53 7 1

Hot Springs 0 18 1 0

Howard 0 24 3 1

Independence 0 21 11 2

Izard 0 32 11 2

Jackson 5 35 15 2

Johnson 1 55 10 2

Lawrence 3 30 8 3

Logan 0 62 12 0

Lonoke 0 30 17 8

Madison 5 14 1 1

Marion 1 37 14 1

Montgomery 0 12 2 0

Newton 0 8 3 0

Perry 0 21 2 1

Pike 0 11 1 0

Polk 0 9 1 0

Pope 1 87 27 4

Pulaski 7 174 122 17

Randolph 1 71 8 1

Saline 0 20 2 4

Scott 0 10 2 0

Searcy 0 8 1 1

Sebastian 4 85 20 6

Sevier 0 12 4 0

Sharp 1 10 2 1

Stone 1 13 12 0

Van Buren 0 14 1 0

Washington 0 74 2 1

White 3 38 15 2

Yell 0 53 12 2

Oklahoma

Adair 0 11 4 0

Atoka 0 30 3 0

Cherokee 0 44 12 3

Delaware 0 18 24 3

Haskell 0 41 2 0

Latimer 0 35 5 1

LeFlore 0 78 6 2

Mayes 0 14 5 0

McCurtain 0 75 2 4

Muskogee 0 46 7 0

Ottawa 0 19 4 0

Pittsburg 0 55 3 0

Pushmataha 0 26 0 0

Sequoyah 0 17 6 3

188
contributed to wetland loss in Missouri (MO DNR

1994).

The Fish and Wildlife Service and the Natural

Resources Conservation Service estimate that historical

wetland loss ranges from 50 to 67 percent in Oklahoma.

Agriculture, including conversion to cropland and

pastureland, is responsible for approximately 80 percent

of the total wetlands lost in Oklahoma. The loss of

adjacent buffers (contiguous areas that support wetlands) threatens the State’s remaining wetlands. Statewide, the loss of wetlands has contributed to (1) decreased quality of surface and ground water supplies,

(2) increased flooding, and (3) reduced ability of wetlands to absorb and cycle sediments and nutrients

(USDI FWS 1992). Unfortunately, information does not

exist that is specific to the Assessment area.

Educating the public about critical functions of

wetlands will be a key to their conservation and restoration. A telephone survey conducted for the Arkansas

Department of Parks and Tourism (Turner 1995) found

that 65 percent of the respondents didn’t think that

destruction of wetlands was an environmental problem

in Arkansas or did not know if it was a problem.

Another survey conducted by the Arkansas MultiAgency Wetland Planning Team reports the following:

• Arkansas respondents do not know a great deal about

wetlands, but many think wetlands are declining.

• Respondents support protection of wetlands for

wildlife habitats both as vital components of the

ecosystem and for future generations.

• A few Arkansas respondents oppose wetland

conservation because they fear government regulation or consider wetlands “just swamps.”

• Many more consider wetland conservation important

and think that State government and landowners

should be responsible for protecting them.

• Some respondents support incentives for landowners

to restore and protect wetlands and endorse partnerships between the government and the private sector

to conserve wetlands.

Implications and Opportunities

The surveys mentioned suggest there is a need for

more education about wetlands. Some support already

exists for wetland conservation and restoration.

Voluntary (incentive based) wetland conservation and

restoration programs for private landowners will increase in importance. Most of the Nation’s wetland

ecosystems (nearly 74 percent) are privately owned.

Federal or State agencies manage 25 percent, and local

governments manage 2 percent (USDA FS 1994). Less

than 5 percent of Arkansas’ original wetlands are

currently protected in State parks, wildlife management

areas, natural areas, and national wildlife refuges (AR

M-AWPT 1997).

Conflicts over land use will have to be resolved if

wetland conservation efforts are to succeed. The

Natural Resources Conservation Service’s 1992 National Resources Inventory (NRI) indicated that wetland

losses due to agriculture will continue, but at a much

slower rate. Commercial and residential development,

drainage and filling, road building, water development

projects, ground water withdrawals, loss of instream

flows, water pollution, and vegetation removal continue

to threaten wetlands (USDI FWS 1992).

Wetland losses will likely continue to decrease and

may approach the national policy of “no net loss” in the

Ozark-Ouachita Highlands in the future. The level of

public support that is generated for wetland conservation and restoration programs will determine whether or

not the wetlands in the Assessment area approach or

attain this “no net loss” status.

189

Chapter 3: The Clean Water Act and Aquatic Restoration Programs

Question 3.1: What laws, policies, and programs

for the protection of water quality, streams,

wetlands, and riparian areas are in place?

Federal and State laws and policies concerning aquatic

resources provide a legal mandate to ensure that human

activities are conducted with consideration for the

protection, preservation, and restoration of our Nation’s

water resources.

This chapter discusses and summarizes many of the

laws and policies that are in effect and reviews the

success of these regulations to date. Topics specifically

addressed include: section 404 of the Clean Water Act

(CWA); the National Pollutant Discharge Elimination

System (NPDES); total maximum daily loads (TMDL’s);

and the control of nonpoint source pollution, which

includes best management practices (BMP’s). Table 3.1

summarizes a number of statutes that have been enacted

and linked to the protection of water quality.

In addition to laws, many federally funded programs

exist to protect, restore, or improve aquatic resources.

This chapter also discusses and summarizes many of

these programs in the context of the Assessment area.

Portions of this chapter draw heavily upon SAMAB

(1996).

 Key Findings

 1. There have been significant changes in regulations

that affect water resources, particularly regulations

concerning nonpoint source problems such as

sedimentation and nutrient loading.

 2. Nonpoint source pollution is one of the major water

quality issues to contend with in the future.

 3. There are several U.S. Department of Agriculture

(USDA) incentive programs that focus on the

restoration of riparian areas and wetlands, including

the Wetlands Reserve Program (WRP) and Environmental Quality Incentive Program (EQIP).

The Clean Water Act (CWA)

The protection of aquatic resources is governed by the

Federal Water Pollution Control Act (FWPCA), which

dates back to 1948. This law was passed after a half

century of debate over the responsibility of the Federal

Government for resolving water pollution problems. The

FWPCA incorporated principles from State and Federal

cooperative program development, limited Federal

enforcement authority, and limited financial assistance.

Now known as the Clean Water Act (CWA), the

FWPCA was largely shaped by the comprehensive 1972

amendments, which are often viewed as the starting point

for modern water pollution control laws. The 1972

amendments established a regulatory system for point

sources of pollution (e.g., pipes that carry industrial

effluent or sewage). They also extended water quality

standards to intra-State waters and provided for implementation of water quality standards through discharge

permits that require monitoring the frequency, amounts,

source, and nature of effluents. The CWA has been

amended several times; the most recent changes occurred with the passage of the Water Quality Act of

1987.

The objective of the CWA is to “restore and maintain

the chemical, physical, and biological integrity of the

Nation’s waters” (CWA 101(a)). The CWA of 1987

explicitly reaffirmed the national goal to eliminate discharges of pollutants into navigable waters of the United

States and, wherever attainable, to achieve water quality

that provides for the protection and propagation of fish,

shellfish, and wildlife. Providing for propagation means

protecting or improving the full range of aquatic habitats

necessary to support reproducing populations of all native

forms of aquatic life (U.S. EPA 1990). The CWA of

1987 further states as a national goal that programs be

developed and implemented for the control of nonpoint

source pollution. (Nonpoint source pollution originates

from diffuse sources such as runoff from construction

activities.) The primary mechanism for controlling

nonpoint source pollution is the adoption and implementation of BMP’s.

191
Table 3.1—A summary of statutes related to water qualitya

Popular name; general citation Specific citation; topic Purpose

Federal Insecticide, Fungicide, and Rodenticide [7 U.S.C. 5506] Water policy with respect to To develop programs for users and dealers of

Act [7 U.S.C. 136] agrichemicals agrichemicals to insure that they and the general

public understand the implications of their

actions and the potential effects on water.

Clean Air Act [42 U.S.C. 7401] [42 U.S.C. 7403] Research, investigation, To improve the understanding of the long- and

training, and other activities short-term causes, effects, and trends of

ecosystem damage from air pollutants, including

their effects on water quality.

Federal Water Pollution Control Act [33 U.S.C. 1251] Congressional declaration of To restore and maintain the chemical, physical,

[33 U.S.C. 1251] goals and policy and biological integrity of the Nation’s water.

Safe Drinking Water Act [42 U.S.C. 300f] Safety of public water systems: definitions To maintain the quality of the Nation’s drinking

water by setting water quality standards.

Soil and Water Resources Conservation Act [16 U.S.C. 2003] Congressional policy and To appraise on a continuing basis the soil, water,

[16 U.S.C. 2001] declaration of purpose and related resources of the Nation and develop

and update periodically a program for furthering

the conservation, protection, and enhancement

of the soil, water, and related resources of the

Nation consistent with the roles and program

responsibilities of other Federal agencies and

State and local governments.

Surface Mining Control and Reclamation Act [30 U.S.C. 1202] Statement of purpose To establish a nationwide program to protect

[30 U.S.C. 1201] society and the environment from the adverse

effects of surface coal mining operations.

Coastal Zone Management Act [16 U.S.C. 1452] Congressional declaration of To protect natural resources including wetlands,

[16 U.S.C. 1451] policy floodplains, estuaries, beaches, dunes, barrier

islands, coral reefs, and fish and wildlife and their

habitats within the coastal zone.

Wild and Scenic Rivers Act [16 U.S.C. 1271] [16 U.S.C. 1271] Congressional declaration of To preserve in a free-flowing condition certain

policy select rivers of the Nation that possess outstand

ing scenic, recreational, geologic, fish and

wildlife, historic, cultural, or other similar values.

National Forest Management Act of 1976 [16 U.S.C. 1604] National forest system land To protect water bodies during timber harvest

[16 U.S.C. 1600] and resource management plans operations to prevent adverse effects on water

quality or fish habitats.

Marine Protection, Research, and Sanctuaries [33 U.S.C. 1401] Congressional finding, policy, To regulate the dumping of materials into the

Act, sec. 2 [33 U.S.C. 1401] and declaration of purpose ocean that would adversely affect human health

or welfare, the marine environment, ecological

systems, or economic potentials.

Solid Waste Disposal Act [42 U.S.C. 6901] [42 U.S.C. 6902(10)] Objectives and national To promote the demonstration, construction,

policy and application of solid waste management,

resource recovery, and resource conservation

systems that preserve and enhance the quality

of air, water, and soil resources.

Executive Orders (E.O.) for Floodplain and E.O. 11988 and 11990 Insures that wetlands and floodplain functions

Wetland Management 11988 and 11990 and values are considered and potential effects

are evaluated during the planning and implemen

tation of all Federal actions. Alternatives will be

considered to avoid adverse impacts; if no

practical alternative is available, mitigation

measures will be implemented to minimize

impacts.

(continued)

192
Considerable debate and concern continue over the

implications of making changes in current water resource legislation. When opposing interest groups

advocate fewer or greater environmental controls,

water pollution issues often become polarized.

Clean Water Act (CWA) Sections

Sections of the CWA that are pertinent to natural

resource management in the Assessment area are

summarized here, and several are then discussed in

more detail.

Section 301 prohibits the discharge of any pollutant

into waters of the United States without a permit and

allows issuance of permits under section 404.

Section 303 requires that water quality standards

contain two components: (1) designated use and

(2) water quality criteria. This section also requires that

projects be consistent with both components. Accordingly, a project that does not comply with a designated

use of the water does not comply with the applicable

water quality standard. Section 303(d) and the EPA’s

Water Quality Planning and Management Regulations

(40 CFR 130) established a process to implement State

water quality standards.

Section 308 gives the EPA the authority to obtain

information that is necessary to carry out enforcement

responsibilities under the CWA.

Section 309(a) requires the EPA to take appropriate

enforcement action to assure compliance with sections

301, 308, 401, and 404 of the CWA.

Section 309(g), as amended in 1987, authorizes the

EPA to assess administrative penalties for, among other

things, discharges resulting from dredge and fill activities

not authorized by sections 301, 308, 401, and 404 of the

CWA.

Section 319 authorizes the EPA to issue grants to

States to implement management programs approved by

the EPA. Under section 319, States assess causes of

nonpoint source pollution within their boundaries, adopt

management programs to control this pollution, and

implement watershed management programs.

Section 401—Water Quality Certification—requires

an applicant for a Federal license or permit to conduct

any activity that “may result in any discharge into the

navigable waters to obtain a State water quality certification so that the discharge will comply with the

applicable provisions of sections 1311, 1312, 1313, 1316,

and 1317 of this title.” Section 401(d) further provides

that “any certification . . . shall set forth any effluent

limitations and other limitations, and monitoring requirements necessary to ensure that any applicant . . . will

comply with any applicable effluent limitations and other

limitations, under sections 1311 and 1312 of this title . . .

and with any other appropriate requirement of State law

set forth under such certification” (33 U.S.C. 401).

Table 3.1—A summary of statutes related to water qualitya(continued)

Popular name; general citation Specific citation; topic Purpose

National Environmental Policy Act (NEPA) [42 U.S.C. 4321] Congressional declaration Declares a national policy to promote efforts

[42 U.S.C. 4371-4375] of purpose that will prevent or eliminate damage to the

environment.

Endangered Species Act (ESA) [16 U.S.C. 1531] Congressional findings and The ESA requires the Secretary of the Interior,

[16 U.S.C. 1531] declaration of purposes and policy through the Fish and Wildlife Service and the

Department of Commerce’s National Marine

Fisheries Service, to identify endangered and

threatened species and to develop recovery plans

for such species. It requires that all Federal

agencies cooperate with State and local agencies

to resolve water resource issues in concert with

the conservation of endangered and threatened

species. The ESA also provides Federal assistance

to States to implement conservation activities

for species likely to become endangered or

threatened.

a For more details and/or recent changes in these and other laws, see the following Web sites: <http://www4.law.cornell.edu/uscode/> and <http://

www.epa.gov/epahome/rules.html>.

193
Section 402(p)—Stormwater Discharges—requires

the EPA to address stormwater discharges associated

with industrial activities. The EPA’s definition of such an

industrial discharge is found in 40 CFR 122.26(b)(14):

“the discharge from any conveyance which is used for

collecting and conveying stormwater and which is

directly related to manufacturing, processing, or raw

materials storage areas at an industrial plant.” These

regulations are targeted at the control of stormwater

runoff from construction sites where disturbed areas

will be 5 acres or larger, including a collection and

delivery system that discharges the runoff through a

point source.

Section 404 of the CWA (33 U.S.C. 1344) directs

the U. S. Army Corps of Engineers to regulate the

“discharge of dredged and fill material into all waters of

the United States, including wetlands.” The intent of the

law is to protect the Nation’s waters from the indiscriminate discharge of material capable of causing

pollution.

Wetlands—Section 404

Established under the FWPCA of 1972, the section

404 regulatory program makes it unlawful to discharge

dredged or fill material into “waters of the United

States” without first receiving a permit from the Corps

of Engineers. The term “waters of the United States”

includes traditionally navigable waters, interstate waters

and wetlands, all impoundments of jurisdictional waters,

all tributaries of waters of the United States, the territorial seas, and wetlands adjacent to any of these waters

(33 CFR 328.3(a); 40 CFR 230.3(s), 232.2).

A discharge of fill material involves the physical

placement of soil, sand, gravel, dredged material, or

other material into these waters. Exemptions were

added to section 404 in 1977 to exclude normal farming,

ranching, and forestry activities that have been active

and ongoing (33 CFR 323.4). For example, if farmers

plow, plant, and harvest in wetlands, they can continue

to do so without a section 404 permit as long as they do

not convert wetlands to dry land. Activities that convert

a wetland that has not been used for farming or forestry

or that is not part of an ongoing program are not exempt

from section 404 permit requirements. The conversion

of a bottomland hardwood wetland to a pine plantation

or for crop production, for example, would not be

exempt. Activities that do not involve discharge of

dredged or fill material into U.S. waters never require a

permit. However, excavation of materials may require a

permit.

Debate continues on the definition of wetlands and

activities that fall under the section 404 exemptions.

Currently, jurisdictional wetlands are defined by the

Corps of Engineers as “those areas that are inundated

or saturated by surface or ground water at a frequency

and duration sufficient to support and that under normal

circumstances do support a prevalence of vegetation

typically adapted for life in saturated soils.” Identification methods for wetlands are outlined in the Wetlands

Delineation Manual (U.S. ACE 1987).

Nationwide and Section 404 Permits

Nationwide permits (NWP’s) are a general type of

permit authorized by the Corps of Engineers for activities that are not specifically restricted (33 CFR

330.2(b)). NWP’s are designed to efficiently regulate 40

types of activities that have minimal impact on water

resources. For example, a specific permit is not required

to stabilize a stream bank that affects less than 500 ft of

stream and does not exceed an average of 1 cubic yard

of material per running foot of bank. Minor road crossings, deposition of fill material, and minor discharges are

also permitted under the provisions of the NWP system

(33 CFR app. (b)). Activities that are not specifically

authorized under the NWP system may require an

individual permit, regional general permit, or a dredgeand-fill permit under section 404 of the CWA. A water

quality certification under section 401 of the CWA or a

waiver from the appropriate State water quality agency

may be required for those NWP’s that result in a

discharge into waters of the United States.

Activities Not Requiring a Section 404 Permit

Most silvicultural activities are exempt from section

404 permit requirements provided they meet 15 road

BMP’s or baseline provisions for road construction.

Specific requirements for BMP application are outlined

in 33 CFR 323.4. For example, “the design, construction,

and maintenance of a road crossing shall not disrupt the

migration or other movement of those species of aquatic

life inhabiting the water body” (33 CFR 323.4(6)(vii)).

194
Mechanical site preparation in seasonally, intermittently, or temporarily flooded wetlands or saturated

wetlands does not require a permit if the BMP’s listed

below are implemented. “Saturated wetlands” are

characterized by subsoil saturated to the land surface

for extended periods during the growing season or by

surface water that is seldom visible and include pine

flatwoods and wet flats (e.g., certain pine-hardwood

forests). To exempt activities from section 404 permit

requirements, managers of forested wetlands must

follow these BMP’s:

• Position shear blades or rakes at or near the soil

surface and windrow, pile, and otherwise move logs

and logging debris by methods that minimize dragging

or pushing through the soil to minimize soil disturbance associated with shearing, raking, and moving

trees, stumps, brush, and other unwanted vegetation;

• Conduct activities in such a manner as to avoid

excessive soil compaction and maintain soil tilth;

• Arrange windrows in such a manner as to limit

erosion, overland flow, and runoff;

• Prevent disposal or storage of logs and logging debris

in streamside management zones (defined as areas

adjacent to streams, lakes, and other water bodies) to

protect water quality;

• Maintain the natural contour of the site, and ensure

that activities do not immediately or gradually convert

the wetland to a nonwetland; and

• Conduct activities with appropriate water management mechanisms to minimize off-site water quality

impacts.

Exemption of Farm and Forest Roads

Section 404(f)(1) exempts farm and forest roads

from 404 permit requirements (33 CFR 323.4(a)(6) and

April 4, 1996, Regulatory Guidance Letter—EPA

Headquarters to Region X). Determination of whether a

road is a forest road under section 404(f)(1)(e) is not

based solely on its use for timber hauling. A forest road

may also provide access for planting, fire control, or

other silvicultural support, but it cannot serve purposes

unrelated to forest management. For example, a road to

a gravel pit used to transport gravel for purposes other

than forest road construction cannot be exempt as a

forest road. Similarly, if a road through a national forest

principally serves people visiting a recreational site—not

the actual business of silviculture—it is not a forest

road. Because farm roads are covered by the same law

and regulation, similar guidance applies to farm roads.

To qualify for a section 404(f) exemption, a forest or

farm road must comply with the requirements of 33

CFR 323.4(a)(6), 33 CFR 323.4(b), and 33 CFR

323.4(c) (implementing section 404(f)(2)). The forest or

farm road must be part of an ongoing silvicultural,

farming, or ranching operation that complies with the

BMP’s of 33 CFR 323.4(a)(6).

National Pollutant Discharge Elimination

System (NPDES)

At the heart of the Clean Water Act is the NPDES,

which regulates both direct and indirect discharges of

pollutants into surface waters. The act makes unlawful

the discharge of any pollutant from a point source into

surface waters without a permit. Thus, no one has the

right to add pollutants to water unless expressly permitted to do so.

Under the CWA, two types of regulation control the

discharge of pollutants—those that are “water quality

based” and those that are “technology based.” Requirements that are water quality based limit permissible

amounts of pollutants allowed in a defined water body

or segment of a water body. The amount of allowable

pollution is based on the capacity of the receiving water

to accept or absorb a pollutant and varies according to

the beneficial use of the water. A beneficial use is

defined as a use for recreation, industrial, or public

drinking water (CWA section 303(c)). The ability of a

receiving water to accept pollution is a function of the

size and flow of a stream, existing water quality conditions, the type of pollutant, and other site specific

factors.

Standards that are technology based tend to dominate

the CWA regulatory system. These standards focus on

the treatment of a pollutant before it is discharged into a

stream and define a level of effluent quality that is

achievable using the best available pollution control

technology. All dischargers must meet minimum treatment requirements. Additionally, toxics—a special class

of harmful pollutants—are singled out for special

treatment by the CWA.

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Water quality standards (designated beneficial uses

and the criteria to protect those uses) are implemented

and enforced through compliance with the NPDES as

administered by the EPA. Under section 402 of the

CWA, a discharger must obtain an NPDES permit from

the EPA or from a State that has an EPA-certified

program (CWA section c 402(b)). Water quality standards (both water quality based and technology based)

are written into permits according to the particular

situation that exists at a given site. The standards

consider the type of pollutant and the condition and

beneficial use of the receiving waters. NPDES permits

are issued for 5 years and may include requirements for

monitoring and reporting of discharge effluents. Discharging pollution without a permit or violation of the

terms or standards of an issued permit may result in civil

and criminal penalties.

Compliance with the terms of an NPDES permit

meets almost all of the CWA’s regulatory provisions and

may be achieved under State authority. A delegated

State program is bound by many of the same statutory

requirements applicable to the Federal program. The

EPA’s goal is to give States the authority to administer

and enforce the NPDES program in its entirety. All of

the States within the Assessment area have NPDES

permitting authority.

Specific requirements for the issuance of an NPDES

permit are described in CWA 402(a)(1). The NPDES

permit system is an effective means of controlling

discharge wastes from discrete point sources that are

easily identifiable (e.g., industrial facilities, municipal

water treatment plants, and combined sewers).

Silvicultural activities, excluded from NPDES permitting requirements per 40 CFR 122.3(3), July 1, 1990,

include “Any introduction of pollutants from nonpoint

source agricultural and silvicultural activities including

storm water runoff from . . . range lands and forest

lands . . . but not discharges from silvicultural point

sources as defined in section 122.7” (section 122.3(e)).

Section 122.7 defines a silvicultural point source as

“. . . any discernible, confined, and discreet conveyance

related to rock crushing, gravel washing, log sorting, or

log storage facilities” that is operated in connection with

silvicultural activities and from which pollutants are

discharged into the waters of the United States. (Log

sorting and storage facilities are those facilities of a

relatively permanent nature found at mills and major

reloading facilities. Landings authorized under a timber

sale contract are part of the harvesting activities and do

not fall into this category.) Section 122.7 does not

address nonpoint source silvicultural activities such as

“nursery operations, site preparation, reforestation and

subsequent cultural treatment, thinning, prescribed

burning, pest and fire control, harvesting operations,

surface drainage, or road construction and maintenance

from which there is natural runoff.”

While the requirements for use designations and

water quality criteria result in fairly uniform water

quality standards among States, actual implementation

of standards varies considerably due to provisions in

some State standards for mixing zones to dilute pollution. These provisions can also result in variability in

NPDES permit limit requirements.

Total Maximum Daily Loads (TMDL’s),

Section 303(d)

Section 303(d) of the Clean Water Act requires

States to prepare a list of impaired surface waters and

to develop a priority ranking for the determination of

total maximum daily loads (TMDL’s). The TMDL’s

guide implementation of State water quality standards.

A TMDL is the sum of (1) a waste load allocation

(WLA), or that portion of a surface water’s loading

capacity that is allocated to an existing or future point

source discharge; (2) a load allocation (LA), or that

portion of the surface water’s loading capacity that is

due to either existing or future nonpoint source pollution

or to natural background sources; and (3) a margin of

safety (MS), or that portion of a surface water’s loading

capacity that is allocated to uncertainty. The relationship

is represented by TMDL = WLA + LA + MS. States

are required to identify and list water bodies where

water quality standards are not met following the

application of technology-based controls and to establish

TMDL’s for these water quality limited waters. The

EPA is required to approve or disapprove State lists and

TMDL’s and to develop lists and TMDL’s when States

fail to do so.

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Antidegradation Policy

Even though the CWA recognizes that States have

the authority to set their own water quality standards,

the EPA reviews the State’s standards and has the

authority to supersede those that do not meet minimum

Federal requirements. For example, a State must

designate “beneficial uses” for its waters such as

“fishable” or “swimmable” that are consistent with

criteria established in the CWA. Furthermore, State

water quality criteria must be shown to protect the

designated uses, and the criteria must be at least as

stringent as Federal guidelines.

The EPA requires that State water quality standards

include “a statewide antidegradation policy” to ensure

that existing instream water uses and the level of water

quality necessary to protect the existing uses be maintained. This policy requires that State standards be

sufficient to maintain existing beneficial uses of navigable

waters and prevent their further degradation. The policy

sets a three-tiered approach for water quality protection.

Tier I maintains and protects existing uses and the water

quality necessary to protect these uses. Tier II protects

the water quality where it is better than that necessary to

protect fishable or swimmable uses. Tier III prohibits a

lowering of existing water quality standards.

States are allowed to designate Outstanding Resource Waters (ORW’s), which are given the highest

level of protection—Tier III—under the Antidegradation

Policy (40 CFR 131).

Nonpoint Source Pollution Control

Nonpoint source pollution is defined as diffuse

sources of pollution not regulated as point sources (U.S.

EPA 1987). Nonpoint sources of pollution include

atmospheric deposition (e.g., acid rain); contaminated

sedimentation (untraceable pollutants found in streambed sediment); and many widely distributed activities

that disturb land and may generate polluted runoff (e.g.,

agricultural activities, logging operations, and onsite

sewage disposal). The control of nonpoint source

pollution is somewhat more difficult than point sources

regulated under the NPDES. Nonpoint source pollution

is less visible, less traceable, and thus more difficult to

control through applying pre-established criteria.

Siltation and nutrients are most often associated with

nonpoint source impacts to water resources. In 1992,

the EPA reported that nonpoint sources of pollution are

more widespread than point sources and introduce vast

quantities of pollutants into our Nation’s waters (U.S.

EPA 1992c). Agricultural activities accounted for 72

percent of the Nation’s impaired rivers. Reporting

States pointed out that siltation and nutrients affected 45

and 35 percent of all impaired stream miles, respectively. Nationally, silviculture (forestry) accounted for

approximately 8 percent of the impaired river miles.

Such a national survey may not capture regional

differences and variability in land use. For example, a

region that is predominantly industrial and urban would

produce a much different type of nonpoint source

pollution than one dominated by agricultural or forestry

activities. Furthermore, because it is impractical for

States to report on the quality of all streams, only 18

percent of the Nation’s 3.5 million miles of rivers were

assessed in the summary document. Notwithstanding the

limitations of such a survey, the scientific community and

regulatory agencies generally recognize that nonpoint

source pollution is one of the major water quality issues

to contend with in the future (U.S. EPA 1989a).

Section 319

As early as 1972, Congress recognized the need to

establish a nationwide program to control nonpoint

sources (section 208—FWPCA). In 1987, it enacted

section 319 of the CWA. The following language was

added to CWA section 101(a)(7): “It is the national

policy that programs for the control of nonpoint sources

be developed and implemented in an expeditious manner

so as to enable the goals of this Act to be met through

the control of both point and nonpoint sources of

pollution.”

Section 319 requires States to assess their waters

and to develop management programs to control and

reduce specific nonpoint source pollution. The section

further authorizes Federal loan and grant funds to assist

States, units of local government, conservation districts,

individuals, farmers, and foresters in managing nonpoint

source pollution. Consistent with section 319, States are

completing their assessments and management programs that, after review by the EPA, will serve as the

197
cornerstone for the national nonpoint source pollution

program (U.S. EPA 1989a). All States within the

Assessment area have implemented or are designing

programs to implement water quality BMP’s to control

nonpoint source pollution.

The primary mechanism for regulating nonpoint

source pollution is the adoption and implementation of

BMP’s. The EPA describes BMP’s as: “Methods,

measures, or practices selected by an agency to meet

its nonpoint control needs. BMP’s include but are not

limited to structural and nonstructural controls and

operation and maintenance procedures. BMP’s can be

applied before, during, and after pollution producing

activities to reduce or eliminate the introduction of

pollutants into receiving waters.” Specific examples of

BMP’s include stabilization and treatment of disturbed

ground during road construction or the proper placement

of waterbars on skid trails during timber harvesting

operations.

State water quality agencies may certify BMP’s for

Federal agencies conducting activities that disturb land.

This certification delegates responsibility to Federal

agencies to protect and restore those waters under their

jurisdiction. The USDA Forest Service has memoranda

of understanding or letters of certification with Arkansas and Oklahoma that confirm that Forest Service

BMP’s meet current requirements of respective State

BMP’s. Forest Service standards and guidelines for

management activities are designed to meet or exceed

all State BMP’s.

In a 1994 study of regional BMP’s for the South,

investigators concluded that, as a whole, forestry

represents a relatively minor source of nonpoint source

pollution compared to sources such as agriculture, urban

development, hydrologic alterations such as dams, and

mining activities (NCASI 1994). However, forestry

activities can become a significant source of nonpoint

source pollution if BMP’s are not properly implemented.

Two examples of effective BMP compliance programs

are Virginia and South Carolina. A study of BMP

effectiveness in South Carolina found that during 1990

and 1991, silvicultural BMP’s were implemented on

84.7 percent of the harvesting operations (Adams and

Hook 1993). A survey of BMP implementation in

Virginia during 1994 indicated that BMP implementation

averaged 91 to 96 percent for related timber harvest

activities (Austin 1994). Both studies concluded that

improper implementation of BMP’s or a lack of awareness of sensitive areas were the major problems with

poor implementation and outcomes of the BMP programs. A recent study of BMP effectiveness monitoring showed no significant impacts to benthic invertebrate communities or water quality when BMP’s are

followed for forestry activities with proper streamside

management (FL DEP 1997).

It has been shown that BMP’s can curtail nonpoint

source pollution. For example, Swift (1988) found that

proper design of forest roads could reduce sediment

washing into streams by more than 90 percent. Swift

pointed out that guidelines for road design are available

to minimize the impacts on water quality from both road

construction and use. It is important that such improved

technology is transferred from researchers to those

involved in forest management as well as to those in

industrial, urban, and rural development (Hackney and

others 1992).

Implications and Opportunities

In the last 10 years, the Nation has witnessed a

significant turning point in water resource legislation and

water pollution control. With the passage of the 1987

Water Quality Act, Congress acknowledged the need to

strengthen existing laws and create new programs to

protect our Nation’s waters. Programs specifically

designed to deal with such problems as nonpoint source

pollution, toxic pollutants, other point source pollution,

and the protection of national treasures, such as the

Mississippi River and Gulf of Mexico, are examples of

this newfound emphasis.

The water pollution regulatory program administered

by the EPA has been largely successful in reducing

pollution and destruction of the Nation’s aquatic resources. Many streams and lakes have gradually

recovered from years of abuse and now support

abundant aquatic life and provide for swimming and

other kinds of recreation. However, recent evidence

shows that much work remains to be done to protect

and enhance aquatic resources for the future.

Ultimately, the responsibility for meeting the mandates of the CWA falls on society as a whole. Private

businesses, citizens, and Federal, State, and local

governments all share in this important effort.

198
Aquatic Restoration Programs

Some federally funded programs to protect, restore,

or improve the Nation’s aquatic resources have a long

history of application in the Assessment area; others are

still in the planning stages. A variety of departments and

agencies are involved, including U.S. Department of

Agriculture agencies (the Forest Service, Natural

Resources Conservation Service, and Farm Service

Agency), U.S. Department of the Interior agencies

(National Park Service, Bureau of Land Management,

and Fish and Wildlife Service), U.S. EPA, and the

Department of the Army, Corps of Engineers.

Each program is unique and is oriented toward

improving specific aspects of the aquatic resource.

Some involve specific non-Federal partners and State

cooperators; others are open to participation by the

general public. All are nonregulatory. A brief synopsis

of these programs follows. More detailed information is

available from sources listed as points of contact and

from individual national forests and State headquarters

of the respective agencies.

Bring Back the Natives

This 50/50 challenge cost-share program targets the

restoration of native fish habitats. National forests

match cooperators (such as Trout Unlimited) to improve

conditions for the restoration of native fish populations in

streams. The National Fish and Wildlife Foundation

receives Federal appropriations; it shares such funds

with public and private partners for the same purpose.

For additional information, contact the nearest Forest

Service national forest supervisor’s office (the agency’s

home page is <http://www.fs.fed.us/>), Trout Unlimited

chapter (Web site is <http://www.tu.org/index.html>), or

the National Fish and Wildlife Foundation (Web site is

<http://www.nfwf.org/bbn/bbn.htm>).

Challenge 21

Challenge 21 is a new Army Corps of Engineers

program to expand the use of nonstructural flood

reduction measures and allow for more effective

coordination of Federal programs on a watershed basis.

The program was developed under the reauthorization

of the Water Resources Development Act. The Corps’

Web site is <http://cw71.cw-wc.usace.army.mil/>.

Clean Water Action Plan

A new initiative, the Clean Water Action Plan,

focuses on partnerships between Federal agencies,

State agencies, and public and private cooperators to

solve water quality related problems on a watershed

basis. The initiative will also target riparian restoration,

grazing allotment strategies, forest road management,

and other stewardship activities on Federal lands. More

information can be obtained at the following USDA and

EPA Web sites: <http://www.nhq.nrcs.usda.gov/

cleanwater/index.html> or <http://www.epa.gov/

cleanwater/action/overview.html>.

Conservation Reserve Program (CRP)

Administered by the Farm Service Agency, the

Conservation Reserve Program (CRP) reduces soil

erosion, reduces sedimentation in streams and lakes,

improves water quality, establishes wildlife habitat, and

enhances forest and wetland resources. The program

encourages farmers to convert highly erodible cropland

or other environmentally sensitive acreage to vegetative

cover such as tame or native grasses, wildlife plantings,

trees, filterstrips, or riparian buffers. Farmers receive an

annual rental payment for the term of the multiyear

contract. Cost sharing is provided to establish the

vegetative cover practices. The Conservation Reserve

Enhancement Program is a new subprogram of the

CRP that focuses on riparian restoration and protection

and sets criteria for enrolling land based on location,

watershed characteristics, and conservation practices

that can be demonstrated to be of unusually high

environmental value. State agencies submit the plans.

The primary benefit of such a program is that landowners who meet these criteria can enroll in CRP

automatically without participating in the bidding process. For additional information, contact a local Farm

Service Agency office or the agency’s Web site at

<http://www. fsa.usda.gov/>.

199
Conservation Technical Assistance

(CTA) Program

The Natural Resources Conservation Service offers

technical assistance through conservation district offices

to private agricultural landowners under the Conservation Technical Assistance program. Farm plans are

prepared with recommended conservation operations

such as erosion control, stream channel improvement,

stream crossings, and riparian area protection. The

Natural Resources Conservation Service identifies costshare options and other programs that the landowner

may wish to pursue to implement the plan. Contact any

Natural Resources Conservation Service district

conservationist for additional information and/or the

agency’s home page on the Web at <http://www.

nrcs.usda.gov/>.

Emergency Watershed Protection

(EWP) Program

The Natural Resources Conservation Service, in

conjunction with other agencies, manages the Emergency Watershed Protection (EWP) program to restore

stream channels, remove blockages, stabilize landslides,

and solve flooding problems caused by catastrophic

natural events. Restoration of watershed conditions

following hurricanes, tornadoes, fires, and other storm

events is provided for both private and public lands,

depending on the source of problems. Costs on these

improvements can be shared or a project can be fully

funded, depending on the immediacy of the need for

treatment. Contact a State conservationist for additional

information or the EWP “Fact Sheet” at <http://

www.nhq.nrcs.usda.gov/CCS/ewpFs.html>.

Environmental Quality Incentives

Program (EQIP)

The Natural Resources Conservation Service

administers the new Environmental Quality Incentives

Program (EQIP) that combines the functions of the

Agricultural Conservation Program, Water Quality

Incentives Program, Great Plains Conservation Program, and the Colorado River Basin Salinity Control

Program. The EQIP establishes conservation priority

areas where significant water, soil, and other natural

resource problems exist and establishes 5- to 10-year

technical assistance contracts and up to 75 percent cost

share for manure management, pest management, and

erosion control. Information on other incentive programs

such as the Wildlife Habitat Incentives Program funded

under the 1996 Farm Bill can be found at the following

Web site: <http://www.nhq.nrcs.usda.gov/>. Contact

any Natural Resources Conservation Service area

office for additional information.

Fisheries Across America

This USDI Fish and Wildlife Service’s cost-share

program provides for aquatic habitat improvement, with

emphasis on information and education. Contact the

Regional Fish and Wildlife Service office in Atlanta, GA

(for Arkansas), Albuquerque, NM (for Oklahoma), or

Minneapolis, MN (for Missouri) for additional information and/or the agency’s Web site <http://www.nwi.

fws.gov/>.

Forestry Incentives Program (FIP)

The Forestry Incentives Program (FIP), administered

by the Natural Resources Conservation Service,

supports forestry BMP’s on privately owned, nonindustrial forest lands nationwide. FIP is designed to benefit

the environment while meeting future demands for

wood products. Eligible practices are tree planting,

timber stand improvement, site preparation for natural

regeneration, and other related activities. FIP is available in counties designated by a Forest Service survey

of eligible private timber acreage. Contact a State or

regional office of the Natural Resources Conservation

Service for more information on FIP and/or the

agency’s home page at <http://www.nrcs.usda.gov/>.

Partners for Wildlife

Partners for Wildlife offers technical and financial

assistance to private landowners of degraded wetlands

or other wildlife habitat. The Fish and Wildlife Service

provides the funds for restoration work administered

under a cooperative agreement with the landowner.

Lands received by easement or fee title transfer by the

Farm Services Administration are also eligible for

200
habitat restoration using these funds. Contact the

Regional Fish and Wildlife Service office in Atlanta, GA

(for Arkansas), Albuquerque, NM (for Oklahoma), or

Minneapolis, MN (for Missouri) for additional information and/or the agency’s Web site at <http://www.

nwi.fws.gov/>.

Rivers, Trails, and Conservation

Assistance Program

The National Park Service’s Rivers, Trails, and

Conservation Assistance Program is oriented toward

local and State governmental agencies. It helps carry

out statewide river assessments, wild and scenic river

studies, and river conservation strategies. Contact the

Midwest Regional Office in Omaha, NB, for additional

information or the agency’s Web site at <http://www.

nps.gov/rtca/>.

Section 319 Nonpoint Source Program

This EPA program provides grants to State water

quality agencies to carry out nonpoint source pollution

planning and management activities. Approximately half

of the grant is used to implement and manage the

overall nonpoint source program; the remainder is

intended to demonstrate BMP’s on the ground. While

the EPA provides grants primarily to States, cooperators

and subgrantees can include public agencies, watershed

associations, universities, and private landowners.

Practices must be oriented to nonpoint pollution prevention or abatement, and projects must include public

education and technology transfer components. Contact

the State water quality management agency for additional information or visit this agency’s Web site at

<http://www.epa.gov/>.

Section 1135 Program

The section 1135 program, aimed at cost sharing with

local sponsors to improve degraded fish and wildlife

habitat, is associated with such Corps of Engineers

water projects as impoundments and channel maintenance activities. For example, 1135 funds helped on a

cost-share basis to reconnect former oxbows and

construct fish ladders to facilitate migration around

dams. Contact any district office of the Corps of

Engineers for additional information. The agency’s Web

site is <http://cw71.cw-wc.usace.army.mil/>.

Small Watershed Program and

Flood Prevention Program

This program authorizes the Natural Resources

Conservation Service to initiate cooperative watershed

studies in which both on- and off-site soil and water

resource impacts are analyzed and corrective actions

recommended. Programs occur only in some watersheds (with 250,000 or fewer acres) having clearly

identified needs and a local sponsoring organization. The

Forest Service provides technical assistance to the

Natural Resources Conservation Service for forestry

analysis.

Typically the lands involved are private, but public

lands may be either treated or utilized to help solve

problems originating on private land. Flood control

structures are an example of a measure taken, often on

public land and for public benefit, to solve problems

generated by upstream activities on private land. If the

Natural Resources Conservation Service determines that

recommended improvement measures are cost effective

and funding is secured, cost sharing becomes available.

Contact a local Natural Resources Conservation Service

district conservationist for additional information and/or

the following Web page: <http://www.nrcs.usda.gov/

NRCSProg.html#Anchor-Watersheds>.

State and Private Forestry,

Cooperative Forestry

Administered by the Forest Service, Cooperative

Forestry programs offer landowner assistance, natural

resource conservation education, urban and community

forestry, and economic action programs. Further

information is available on the Internet at this Web site:

<http://willow.ncfes.umn.edu/coop/coop.htm>.

Stewardship Incentives Program (SIP)

The Stewardship Incentives Program (SIP), administered by the Forest Service but delivered at the State

level by State forestry agencies, provides funds for the

development of stewardship plans for private, nonindustrial landowners. These plans provide for such

201
activities as timber and wildlife management, recreational use, and water quality improvement. Landowners agree to carry out practices compatible with the

plan and can receive cost-share assistance for approved

practices. State forestry agencies establish most of the

terms of the approved practices (e.g., wildlife habitat

improvement, reforestation, and erosion control). An

interagency stewardship committee guides the program

statewide. Eligible landowners must have an approved

Forest Stewardship Plan and own 1,000 or fewer acres

of qualifying land. Authorizations may be obtained for

exceptions of up to 5,000 acres. Contact the nearest

Forest Service office (home page <http://www.

fs.fed.us/>) or the local county forester for additional

information.

Watershed and River Basin Planning

and Installation (Public Law 566)

This Department of Agriculture program, coordinated

by the Natural Resources Conservation Service,

provides technical and financial assistance (in cooperation with local sponsoring organizations, State, and other

public agencies) to plan and install watershed-based

projects on private lands to create and restore wetlands.

Some of the purposes for watershed projects are flood

prevention; soil erosion reduction; protection of rural,

municipal, and industrial water supplies; sedimentation

control; and fish and wildlife habitat enhancement.

Contact a State conservationist for additional information and/or the following Web site: <http://www.

ftw.nrcs.usda.gov/pl566/pl566.html>.

Wetlands Reserve Program (WRP)

The Wetlands Reserve Program (WRP), administered by the Natural Resources Conservation Service,

funds the purchase of easements on private wetlands

and follows up on wetland restoration and revegetation

efforts. Eligible lands include altered but restorable

wetlands and adjacent, critical nonwetlands. The

Natural Resources Conservation Service and Fish and

Wildlife Service develop management plans with which

landowners agree. Landowners then become responsible for 25 percent of the restoration cost and maintenance. Land use is restricted to activities compatible

with maintaining wetland functions. All 50 States are

eligible for the program.

The revised WRP required that, beginning on October 1, 1996, one third of the total program acres be

enrolled in permanent easements, one third in 30-year

easements, and one third in cost-share agreements for

restoration only. Individuals may choose the category

for their eligible land when they apply. Contact any

Natural Resources Conservation Service area office for

additional information and/or the agency’s home page at

<http://www.nrcs.usda.gov/>.

Implications and Opportunities

To fulfill the goals of the Clean Water Act and

related watershed improvement incentive programs,

State and Federal agencies administer laws, policies,

and programs for aquatic resource protection. Water

quality and riparian problems still persist in some

watersheds of the Assessment area, but cooperative

approaches for restoration and protection have improved and protected conditions of some aquatic

ecosystems. Although USDA and other Federal agencies have had local successes with various restoration

and stewardship programs and regulatory agencies have

had similar successes with water quality enforcement

and nonpoint source grant programs, results have not

been quantified or evaluated in the Assessment area.

No conclusion, therefore, can currently be drawn about

the effectiveness of laws, policies, and programs on

improving aquatic conditions in the Assessment area.

Such an evaluation might prove very valuable in identifying and implementing future laws, policies, and

voluntary programs for aquatic resources.

In the future, States, Federal agencies, and local

partners will reprioritize actions to restore watersheds

and aquatic resources. These efforts will need to be at a

large enough scale to include all watershed components

such as aquatic ecosystems, terrestrial components, air,

and socioeconomic conditions. Finally, the sharing of

natural resource information and spatial data among

State, Federal, private, and local partners can help

achieve goals of both the CWA and forest stewardship.

This Assessment is an attempt to encourage such

sharing in the future.

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Chapter 4: Effects of Human Activities

State and Federal Classifications of

Water Quality

This first section of Chapter 4 discusses some State

and Federal classifications of waters within the Assessment area. The Aquatic Team focused on three areas for

this discussion: “Outstanding Resource Waters,” “Impaired Waters,” and “Index of Watershed Indicators.” In

addition, under the direction of the EPA, each State is

currently completing a Unified Watershed Assessment.

Because of time constraints, this information was not

included in this report. However, information concerning

the Unified Watershed Assessment can be found at the

following Web site: <http://www.epa.gov/cleanwater/

uwafinal/>. Final reports can be found at <http://

www.deq.state.ok.us/Water1/home/index.html> for

Oklahoma, at <http://www.cares.missouri.edu/mowiap/>

for Missouri, and at <http://www.ar.nrcs.usda.gov/uwa/

index.htm> for Arkansas.

Outstanding Resource Waters (ORW’s)

Question 4.1: Which streams and rivers have been

designated as Oustanding Resource Waters by

pollution control agencies in Missouri, Oklahoma,

and Arkansas?

Outstanding Resource Waters (ORW’s) serve as

“baselines” against which other waters within the same

ecoregion may be compared. These waters include

extraordinary (State determined), ecologically sensitive

(State determined), and legislatively designated (State or

Federally designated) streams and lakes. Extraordinary

waters are those recognized by the States as having

exceptional combinations of physical, chemical, and

biological characteristics that sustain healthy aquatic

habitats. Ecologically sensitive waters provide habitat for

threatened, endangered, or endemic aquatic or semiaquatic species. Legislatively designated waters in the

Assessment area include the National Wild and Scenic

River System and State scenic river systems.

Within the framework of the Clean Water Act (CWA),

each State designates its own ORW’s and develops an

antidegradation policy that stipulates that designated uses

of a water body (e.g., public water supply and recreation)

cannot be impaired to allow greater discharge of pollutants into that water body. The CWA prohibits any

lowering of existing water quality in ORW’s. For further

discussion of the CWA, see Chapter 3 of this report. See

Chapter 5 of the Ozark-Ouachita Highlands Assessment: Social and Economic Conditions (USDA FS

1999a) for a further discussion of legislatively designated

waters and their associated recreational activities.

 Key Findings

 1. There are 4,113 stream miles of extraordinary,

ecologically sensitive, and legislatively designated

waters within the Assessment area. A single body

of water may fall within more than one of these

categories.

 2. Of those miles, 17 percent occur on or adjacent to

national forest lands.

Data Sources and Methods of Analysis

The Aquatic Team used maps and descriptions from

each State’s water quality regulations (AR DPCE 1991,

MO DNR 1996a, OK WRB 1996) to include extraordinary, ecologically sensitive, and legislatively designated

waters on the EPA’s River File version 3 (RF3) data

layer. While the Aquatic Team made every effort to

accurately depict the characteristics of these waters of

the Assessment area, errors are present because of the

difficulty of locating stream segments (many stretches of

extraordinary waters were simply based on stream

names). Because of this difficulty and occasional differences in stream densities mapped on the RF3 layer, the

Aquatic Team analyzed and displayed the identified

extraordinary waters using the EPA’s River File version 2

(RF2) data layer. Unfortunately, this data base identifies a

stream as an ORW only and does not identify mapped

stream segments as extraordinary, ecologically sensitive,

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Table 4.1—Miles of Assessment area streams classified as

Outstanding Resource Waters (ORW’s) (by State and

national forest), portion of these ORW’s in the States and

national forests, and portion of the Assessment area

occupied by each national forest

Portion of NF lands as

State, ORW portion of

national Length of stream Assessment

forest ORW’s miles area

Miles - - - - - - - Percent - - - - - - -

Oklahoma 563 14

Arkansas 3,089 75

Missouri 461 11

Total 4,113 100

Ouachita NF 364 9 3

Ozark NF 226 5 2

Mark Twain NF 111 3 3

Total 701 17 9a

ORW’s = Outstanding Resource Waters; NF = national forest. a Difference in total is a result of rounding.

or legislatively designated. The Aquatic Team identified

streams within national forest lands by intersecting

stream segments with each forest’s ownership layer. All

stream mileages were taken from the RF2 data.

Patterns and Trends

State agencies are responsible for monitoring extraordinary, ecologically sensitive, and legislatively

designated waters. As of late 1997, 4,113 stream mi in

the Assessment area fit within one or more of these

categories (table 4.1 and fig. 4.1).

National forests occupy only about 9 percent of the

Assessment area, but 17 percent of all extraordinary,

ecologically sensitive, and legislatively designated

waters occur on or near national forest lands. A significant percentage of ORW’s exist on lands managed by

the National Park Service as well, but the team did not

develop quantitative estimates for them. The U.S. Army

Corps of Engineers and various State agencies are

responsible for smaller percentages of the region’s

ORW’s.

The 1996 land exchange between the Ouachita

National Forest and Weyerhaeuser Corporation increased the percentage of extraordinary and ecologically sensitive waters within the Ouachita National

Forest, particularly in Oklahoma. With the possible

exception of Crooked Creek in Arkansas, which has

been proposed as an extraordinary stream, no other

additions or removals of streams from the network of

ORW’s in the Highlands are likely in the near future.

See Chapter 5 of this Assessment’s Social and

Economic Conditions (USDA FS 1999a) for a list of

streams that might be considered for special Federal or

State designations over the next 5 to 10 years.

Implications and Opportunities

Some of the richest and highest quality streams in the

Highlands are located on national forests and national

rivers, where their careful stewardship is a high priority.

Application of appropriate best management practices

(BMP’S) in watersheds feeding into these streams is

critical to their long-term health.

The precise locations of ORW’s are not available in

digital format, hampering computer analysis. An opportunity exists for the national forests and State agencies

to work together to develop an accurate, complete data

base of ORW’s of the Highlands.

Impaired Waters

Question 4.2: Which waters have pollution

control agencies in Missouri, Oklahoma, and

Arkansas determined to be impaired or

threatened, and what are the suspected sources

of impairment?

As a result of the CWA, each State is responsible for

identifying impaired or threatened waters. Impairment

occurs when a water body is not fully supporting its

designated beneficial uses (e.g., as a domestic water

supply, swimming area, or fishery). Impairment may

result from a point source (such as untreated sewage

flowing out of a pipe directly into a water body or one of

its tributaries) or a nonpoint source (such as erosion

moving from a field into a stream). After a State

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Figure 4.1—Locations of Outstanding Resource Waters (ORW’s) within the Assessment area.

pollution control agency monitors and evaluates streams

and lakes to see if their beneficial uses are being

protected, the State designates contaminated waters as

impaired or threatened. At a minimum, each State must

list the contaminant(s) and probable source(s) of

contaminants affecting each impaired or threatened

water body. (For this report, a contaminant is defined as

an unwholesome or undesirable element that causes

water to be unfit for use, e.g., raw sewage in a lake

used for fishing and swimming. A contaminant source

(or source of impairment) is the origin of the undesirable

element, e.g., a factory could be a primary source and a

dairy farm could be a secondary source of bacteria that

impairs a stream.)

Each State formally reports the results of its monitoring efforts to the EPA, including impaired water bodies

as is required under section 303(d) of the CWA. These

lists were taken from the State 305(b) reports to

Congress (AR DPCE 1996, MO DNR 1994, OK DEQ

1996). While these reports are rich in information, the

Aquatic Team listed impaired streams by contaminants

and sources of contaminants only to allow for a common discussion of impaired waters within the Assessment area among the three States.

Oklahoma

Arkansas

Missouri

Outstanding Resource Waters

205
 Key Findings

 1. The State 305(b) lists identify 5,588 mi of impaired

streams within the Assessment area.

 2. The predominant sources of impairment of water

quality (primary and secondary sources combined)

within the Assessment area are agriculture (36.1

percent), unknown (10.9 percent), and mining (10.2

percent).

 3. Of the 5,588 mi of impaired streams, 133 are

associated with national forest lands.

 4. Major sources of impairment for stream segments

within national forest lands include agriculture, road

construction, and silviculture.

Data Sources and Methods of Analysis

The Aquatic Team took the lists of threatened or

impaired waters from the 1996 305(b) reports from

Oklahoma and Arkansas and from the 1994 Missouri

305(b) report (AR DPCE 1996, MO DNR 1994, OK

DEQ 1996). The team then linked these reported

impaired streams with the EPA’s RF3 data base. To

simplify data, the team analyzed the results in EPA’s

River File version 1 (RF1) data layer and then categorized the data by the source of contamination. Stream

mileages were taken from the EPA’s RF1 data layer.

The team sorted the data for stream segments having

their centers within national forest lands. The original

data from Oklahoma and Missouri were not linked to a

Geographic Information System (GIS) layer or data

base; therefore, the team entered these data based on

maps or narratives. As a result, all stream mileages are

based on the developed GIS layers and will not necessarily match published values. Because each State uses

different criteria for monitoring and reporting, the

Aquatic Team identified impaired waters only rather

than all waters monitored by the States.

Patterns and Trends

Within the Assessment area, the State 305(b) reports

identify 5,588 mi of stream as not fully supporting or

only partially supporting beneficial uses (table 4.2).

Figure 4.2 displays the locations of those impaired

streams. The majority of impaired streams occur in

Table 4.2—Stream miles within the Assessment area

identified as impaired in State 305(b) reports by primary and

(where known) secondary source(s) of contamination

Source of contamination

(primary, secondary) Milesa

Acid deposition 320

Agriculture 1,022

Agriculture, acid deposition 2

Agriculture, flow modification 73

Agriculture, industry 53

Agriculture, mining 362

Agriculture, municipal 283

Agriculture, natural 369

Agriculture, riparian modification 41

Agriculture, road construction 280

Agriculture, silviculture 328

Agriculture, urban 74 Flow

regulation 1 Flow

regulation, unknown 19

Industry 42

Industry, municipal 18

Mining 269

Mining, municipal 43

Mining, natural 158

Mining, unknown 9

Municipal 143

Municipal, agriculture 24

Municipal, industry 24

Municipal, road construction 40

Municipal, unknown 21

Natural 9

Road construction 21

Road construction, agriculture 39

Road construction, municipal 48

Road construction, silviculture 110

Silviculture, acid deposition 193

Unidentified 274

Unknown 838

Unknown, agriculture 10

Urban, agricultural 19

Urban, natural 11

Total 5,588

a Rounded to nearest whole number.

Source: AR DPCE (1996), MO DNR (1994), OK DEQ (1996).

206
Figure 4.2—Locations of impaired streams within the Assessment area as identified in the Oklahoma,

Missouri, and Arkansas 305(b) reports.

Oklahoma and Arkansas. However, this is a result of

each State’s reporting process and is not necessarily

indicative of a negative trend in water quality.

By combining the primary and secondary sources of

impairment and expressing the associate stream mileages as a percent, the team found that agriculture (as

either a primary or secondary source) is the major

source (36.1 percent) of impairment to water quality

across the Assessment area (table 4.3). The “unknown”

source on table 4.3 is primarily linked to bacteria,

alterations of pH, and suspended solids and is the

second greatest “source” of contamination, representing

10.9 percent of the impaired streams. Mining, the third

greatest source of impairment, contaminates 10.2

percent of all affected streams.

Of the 5,588 mi of impaired streams within the

Assessment area, 133 are associated with national

forest lands (table 4.4). The Aquatic Team arrived at

this figure by summing the lengths of stream segments

that had their centers within national forest land. This

exercise determined whether the impaired stream

segments are on national forest lands, not whether the

source of impairment is on national forest lands or other

lands upstream (i.e., although a stream segment within

national forest boundaries may be impaired, the source

of the impairment may have come from sources upstream, outside the national forest boundaries). The

team found that major sources of impairment on stream

segments within national forest boundaries include

agriculture, road construction, and silviculture.

Oklahoma

Arkansas

Missouri

Threatened or impaired

waters

207
Table 4.3—Sources (primary or secondary) and types of contaminants and their relative contributions to stream impairment in the

Assessment areaa

Portion of

Contaminant impaired

source Contaminant(s) stream miles

Percent

Acid deposition Altered pH 6.2

Agriculture Bacteria, nutrients, organics, pesticides, and siltation 36.1

Flow regulation Flow alteration, nutrients, organics, and siltation 1.1

Industry Bacteria, minerals, and nutrients 1.7

Mining Metals, minerals, nutrients, organics, altered pH, unknown toxic, and siltation 10.2

Municipal Bacteria, minerals, nutrients, and organics 7.8

Natural Metals, altered pH, and unknown toxic 6.6

Riparian modification Habitat alterations 0.5

Road construction Siltation 6.5

Silviculture Pesticides and nutrients 7.7

Unidentified Nutrients 3.3

Unknown Bacteria, mercury, noxious plants, nutrients, organics, pesticides, altered pH, 10.9

siltation, suspended solids, and unknown toxic

Urban Nutrients, organics, and pesticides 1.3

a Total is less than 100 percent due to rounding; see “Glossary of Terms” for definitions of impairment, contaminant source, and contaminant.

Source: AR DPCE (1996), MO DNR (1994), OK DEQ (1996).

Table 4.4—Stream miles within national forests affected by contaminants, as identified in State 305(b) reports showing primary

and (where listed) secondary sources and associated contaminants

National forest Stream miles Contaminant source(s) Contaminant(s)

Mark Twain 5.11 Agriculture Siltation

Total 5.11

Ouachita 8.79 Acid deposition Altered pH

24.71 Agriculture Siltation and bacteria

2.90 Agriculture, industry Siltation and bacteria

24.72 Road construction, silviculture Siltation

3.92 Unknown Bacteria, pesticides, and altered pH

Total 65.04

Ozark 1.74 Agriculture, mining Siltation and nutrients

2.16 Agriculture, road construction Siltation

35.76 Agriculture, silviculture Siltation

8.20 Municipal Bacteria

15.10 Road construction, municipal Siltation and bacteria

Total 62.96

Grand total 133.11

Source: AR DPCE (1996), MO DNR (1994), OK DEQ (1996).

208
Implications and Opportunities

The Forest Service needs to work closely with

appropriate State agencies to share data and resources

related to monitoring and evaluating waters in and near

national forest lands. Where monitoring identifies

problems on public lands, joint State and Federal remedies can be sought. Where impaired streams cross

multiple ownerships, opportunities exist for cooperative

watershed improvement efforts among willing landowners, local organizations, the Forest Service, and other

agencies.

EPA Index of Watershed Indicators (IWI)

Question 4.3: How does the condition of

Assessment area watersheds compare with the

rest of the United States?

The Index of Watershed Indicators (IWI) is an EPA

program designed to describe broadly the condition and

vulnerability (sensitivity) of aquatic systems in each of

the 2,111 watersheds of the continental United States.

This index establishes baseline conditions and allows

scientists and others to monitor progress toward achieving clean water goals at the watershed scale. The IWI

uses watersheds (hydrologic units with an eight-digit

code) as its basic units. Fifty of these watersheds occur

within the Assessment area.

 Key Findings

 1. Of the 50 watersheds within the Assessment area,

24 (48 percent) are designated as having “better

water quality and low vulnerability to stressors”

(pollutants that could further strain the aquatic

resource). Nationwide, EPA gave this rating to only

9 percent of watersheds.

 2. Within the Assessment area, only the Spring

watershed in the Neosho-Illinois River Basin has a

rating of “more serious water quality problems and

high vulnerability to stressors.” The South Grand

and Fourche La Fave watersheds are in the

following class: “more serious water quality

problems and low vulnerability to stressors.”

Data Sources and Methods of Analysis

The EPA compiled the data base using individual

State 305(b) reports for information about (1) rivers that

meet designated uses set in State and tribal water

quality standards, (2) indicators of source water conditions for drinking water systems, and (3) contaminated

sediments. States also provided consumption advisories

concerning potential problems involved with eating fish

and wildlife found in the Assessment area. Indicators of

source water conditions for drinking water systems and

water quality data for pollutants came from the EPA’s

data STOrage and RETrieval system (STORET). (For

more information on this water quality data base, see

the Web site at <http://www.epa.gov/owow/

STORET>.) Wetlands loss was determined using the

USDA, Natural Resources Conservation Service,

National Resource Inventory (NRI) data base. (For

more information about the NRI, see <http://www.

nhq.nrcs.usda.gov/NRI/intro.html>.)

Vulnerability scores of pollutant loads above permitted discharge limits are taken from the National Pollutant Discharge Elimination System (NPDES) permits. A

watershed with low vulnerability suggests pollutants or

other stressors are low, and, therefore there exists a

lower potential for future declines in aquatic health.

Actions to prevent declines in aquatic conditions in these

watersheds are appropriate but at a lower priority than

in watersheds with higher vulnerability. The index of

agricultural runoff potential is taken from the NRI data

base. Population change is taken from USDC Bureau of

the Census data. Hydrologic modification caused by

dams is taken from the National Inventory of Dams

data base. Urban runoff potential is derived from the

EPA’s Urban Runoff Potential Measure and Bureau of

the Census data. Information about aquatic and wetlands species at risk is taken from the Natural Heritage

Data Center in each State. The estuarine pollution

susceptibility index is derived from Coastal and Estuarine and Marine Eutrophication Vulnerability data.

Watershed condition scores. The EPA assigns

a “condition score” to each river within each watershed. The “condition score” is based on the following

criteria: (1) whether it meets some or all designated

uses set for State and tribal water quality standards,

(2) fish and wildlife consumption advisories, (3) indicators of source water condition for drinking water

209
systems, (4) contaminated sediments, (5) ambient water

quality data (four toxic pollutants and four conventional

pollutants), (6) and wetlands loss index. Condition

scores are then categorized as follows:

• Better water quality,

• Water quality with less serious problems, or

• Water quality with more serious problems.

Watershed vulnerability scores. The EPA assigns

a vulnerability rating of high or low to watersheds by

scoring them according to the following criteria:

• Aquatic and wetlands species at risk,

• Amount of toxic and conventional pollutants discharged above permitted limits,

• Urban runoff potential,

• Index of agricultural runoff potential,

• Population change,

• Hydrologic modification caused by dams, and

• Estuarine pollution susceptibility index (not applicable

to the Assessment area).

Condition and vulnerability. These two sets of

indicators (condition and vulnerability) are then combined to create the following ratings:

• Better water quality and low vulnerability to

stressors,

• Better water quality and high vulnerability to

stressors,

• Less serious water quality problems and low vulnerability to stressors,

• Less serious water quality problems and high vulnerability to stressors,

• More serious water quality problems and low vulnerability to stressors,

• More serious water quality problems and high

vulnerability to stressors, and

• Insufficient data exists to make an assertion of

condition or vulnerability.

Access to more detailed information about IWI is

available at: <ftp.epa.gov/pub/iwi/surf/> and through the

search engine “Surf Your Watershed” at: <http://www.

epa.gov/surf2/>.

To rate “condition,” individual data layers received

scores of 0—no effect or no information, 1—moderate

effect, or 2—the worst case. Assessed rivers meeting

all designated uses were weighted with a possible score

of 0, 6, 12, or 18. Scores were summed for each

watershed. When scores for condition exceed 18, the

watershed is considered to have serious water quality

problems. Watersheds with combined scores between 8

and 17 are classified as having less serious water

quality problems. Scores below 8 are associated with

watersheds that have better water quality (once they

have been determined to have sufficient data for

classification).

The eight stressors for the vulnerability index were

summed. Values less than 8 were scored as low vulnerability and values greater than 8 were scored as high

vulnerability (U.S. EPA 1997a).

Patterns and Trends

Data for this analysis were accessed in June of 1997.

Of the 50 watersheds within the Assessment area, 24

(48 percent) score as having better water quality with a

low vulnerability to activities that could further stress the

aquatic resource (fig. 4.3). Nationwide, only 9 percent

score this high. Compared to the rest of the continental

United States, watersheds within the Assessment area

generally have a higher water quality and are not readily

susceptible to stressors. No watersheds were identified

as having better water quality and high vulnerability to

stressors. Sixteen watersheds were classified as less

serious water quality problems and low vulnerability to

stressors, and one watershed (the Lower Neosho

watershed in the Neosho-Illinois River Basin) was rated

as “less serious water quality problems and high vulnerability to stressors.” To simplify figure 4.3, the watersheds with less serious water quality problems and those

with high and low vulnerability were combined. Six

watersheds had insufficient data to determine condition

or vulnerability.

Within the Assessment area, only the Spring watershed in the Neosho-Illinois River Basin scored as having

more serious water quality problems with a high vulnerability. This watershed lies in a karst area (a landscape

high in limestone and marked by numerous caves and

springs) near the intersections of the Arkansas, Missouri, and Oklahoma State lines. Animal wastes and

other agriculture-related runoff are the major sources of

the water quality problems there. Two other watersheds—South Grand and Fourche La Fave—were

classed as having “more serious water quality problems

and low vulnerability to stressors.” Neither watershed is

fully supporting its beneficial uses.

210
Figure 4.3—Water quality (WQ) categories of Assessment area watersheds as determined by the Index of Watershed

Indicators (IWI).

Implications and Opportunities

The IWI, which permits comparisons within and

between regions, is a useful index of watershed conditions across the Nation. Regular updating of the IWI

would provide measures of progress toward meeting

goals for water quality and watershed conditions.

The only watershed with serious water quality

problems and an appreciable amount of national forest

land is the Fourche La Fave.

Point Sources

Point sources of water pollution are single conveyances from which contaminants enter a stream; they

often originate from municipal and industrial processes.

Examples of point sources include wastewater discharge pipes, stormwater drains, mine pits, industrial

facilities, smokestacks, and ditches.

Unlike nonpoint pollution, water pollution from point

sources enters streams or lakes at identifiable locations

Oklahoma

Arkansas

Missouri

IWI categories

Better WQ, low vulnerability

Less serious WQ, combined vulnerability

More serious WQ, low vulnerability

More serious WQ, high vulnerability

Insufficient data

211
and can be easily monitored. The 1972 amendments to

the CWA prohibit the discharge of any pollutant to

navigable waters from a point source unless the discharge is authorized by an NPDES permit. Efforts to

improve water quality under the NPDES have traditionally focused on reducing pollutants in discharges of

industrial process wastewater and municipal sewage. At

the onset of the program in 1972, many sources of

industrial process wastewater and municipal sewage

were not adequately controlled, thus they represented

pressing environmental problems. In addition, discharges

from sewer pipes and industrial processes were easily

identified as responsible for poor, often drastically

degraded water quality conditions. Since enactment of

the 1972 amendments to the CWA, significant progress

has been made in cleaning up industrial process wastewater and municipal sewage.

The EPA stores information on wastewater dischargers in the Permits Compliance System (PCS). The PCS

updates information about dischargers, including locations, permitted volumes and concentrations of discharges, monitoring requirements, and information on

permit violations. In addition to the PCS, an EPA data

base integrates data from three other major EPA

program systems: the Comprehensive Environmental

Response, Compensation, and Liability Information

System (CERCLIS), Toxic Release Inventory System

(TRIS), and Resource Conservation and Recovery

Information System (RCRIS).

CERCLA and Superfund Sites

Question 4.4: What are the current status and

potential effects of hazardous waste sites on

aquatic resources within the Assessment area?

The Comprehensive Environmental Response,

Compensation, and Liability Act (CERCLA) was

enacted in 1980 and amended by the Superfund Amendments and Reauthorization Act of 1986. These acts

establish broad authority for the Federal Government to

respond to problems posed by the release, or threat of

release, of hazardous substances, pollutants, or contaminants. The CERCLA also imposes liability on those

responsible for releases and provides the authority for

the Government to undertake enforcement and abatement action against responsible parties. The EPA’s data

base CERCLIS contains information on hazardous

waste sites, site inspections, preliminary assessments,

and remedial status. Customers have several ways of

obtaining access to CERCLIS information. For background on the Superfund, the National Priorities List

(which contains hazardous waste sites eligible for longterm cleanup), CERCLA, and CERCLIS, consult the

following Web site: <http://www.epa.gov/superfund/>.

 Key Findings

 1. Within the Assessment area, there are 798 sites in

CERCLIS.

 2. Of the 798 sites, 15 are Superfund sites on the

National Priorities List (NPL).

Data Sources and Methods of Analysis

Data were retrieved from the EPA’s CERCLIS and

Better Assessment Science Integrating Point and

Nonpoint Sources (BASINS) data bases (U.S. EPA

1996a, b) and the Right-To-Know Network (1997). A

CERCLIS query allows the user to locate and learn

about the status of Superfund facilities. The number of

sites was normalized by dividing the number of sites by

the area of the watershed. This value is then expressed

as the number of sites per 1,000 square miles (mi2

).

Patterns and Trends

The CERCLIS data base identified 798 sites within

the Assessment area. Watersheds that have the highest

number of CERCLIS sites (including Superfund sites)

are the Meramec, Spring (Neosho-Illinois River Basin),

and Lower Arkansas-Maumelle with 162, 81, and 49

sites, respectively. The Meramec, Lower ArkansasMaumelle, and Dirty-Greenleaf watersheds have the

highest densities of CERCLIS sites with 75, 44.26 and

31.69 sites per 1,000 mi2

, respectively. Currently, the

rate of identification of new CERCLIS sites is low.

Furthermore, CERCLIS sites are not usually significant

sources of the types of pollution that are causing

widespread impacts in the Assessment area. Many

212
Figure 4.4—Locations of Superfund sites in the Assessment area as reported by Oklahoma,

Arkansas, Kansas, and Missouri to the EPA (U.S. EPA 1996a, b). (See table 4.5 for names of

watersheds with Superfund sites.)

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●

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● Superfund sites

Oklahoma

Arkansas

Missouri

CERCLIS sites do not require immediate action, and

most have a low priority for future remedial action.

There are 15 Superfund sites in the Highlands: 4 in

Arkansas, 1 each in Kansas and Oklahoma (in very

close proximity to each other along their shared boundaries), and 9 in Missouri (fig. 4.4). These sites are

eligible for extensive, long-term cleanup under the

Superfund program. Types of facilities include industrial

landfills and mining and wood products facilities. The

Superfund sites in the Assessment area generally are

found in developed areas such as the Meramec, Sac,

and Spring (Neosho-Illinois River Basin) watersheds,

which together have 10 of the 15 sites (table 4.5).

Implications and Opportunities

As a whole, the Assessment area does not experience widespread impacts due to CERCLIS sites.

However, these contaminated sites can have significant

localized impacts on the environment and human health.

To address watershed- and landscape-scale impacts,

States should assess CERCLIS sites and sanitary

landfills that contribute contamination that may be linked

to fish advisories or violations of water quality standards

in nearby surface and ground water. If current Federal

and State hazardous waste management regulations and

practices are maintained, the number of CERCLIS sites

should decrease over time.

213
Table 4.5—Superfund (NPL) and CERCLIS sites within the aquatic study area, by watershed

River basin Watershed Superfund CERCLIS NPL site Density, all

Watershed name code (HUC) Area sites sites density sites

Mi2 - - -Sites per 1,000 mi2 - - -

Osage River Basin

H.S. Truman Reservoir 10290105 1,211 2 0 1.65

Sac 10290106 1,971 3 28 1.52 14.21

Pomme de Terre 10290107 848 2 0 2.36

South Grand 10290108 2,048 18 0 8.79

Lake of the Ozarks 10290109 1,385 8 0 5.78

Niangua 10290110 1,031 5 0 4.85

Lower Osage 10290111 1,077 7 0 6.50

Gasconade River Basin

Upper Gasconade 10290201 1,788 4 0 2.24

Big Piney 10290202 756 2 0 2.65

Lower Gasconade 10290203 1,035 8 0 7.73

Meramec River Basin

Meramec 07140102 2,160 4 162 1.85 75.00

Bourbeuse 07140103 837 19 0 22.70

Big 07140104 962 29 0 30.15

Upper St. Francis River Basin

Upper St. Francis 08020202 1,298 13 0 10.02

Neosho-Illinois River Basin

Lake O’ the Cherokees 11070206 920 1 15 1.09 16.30

Spring 11070207 2,578 3 81 0 31.42

Elk 11070208 1,031 3 0 2.91

Lower Neosho 11070209 2,210 37 0 16.74

Illinois 11110103 1,651 34 0 20.59

Arkansas River Basin

Dirty-Greenleaf 11110102 789 25 0 31.69

Robert S. Kerr Reservoir 11110104 1,807 34 0 18.82

Poteau 11110105 1,904 9 0 4.73

Frog-Mulberry 11110201 1,259 1 4 0.79 3.18

Dardanelle Reservoir 11110202 1,861 9 0 4.84

Conway-Point Remove 11110203 1,137 6 0 5.28

Petit Jean 11110204 1,090 1 5 0.92 4.59

Cadron 11110205 769 1 0 1.30

Fourche La Fave 11110206 1,119 2 0 1.79

Lower Arkansas-Maumelle 11110207 1,107 49 0 44.26

Kiamichi-Little River Basin

Kiamichi 11140105 1,821 2 0 1.10

Upper Little 11140107 1,409 8 0 5.68

Mountain Fork 11140108 856 1 2 1.17 2.34

Lower Little 11140109 1,975 6 0 3.04

Ouachita-Saline River Basin

Ouachita Headwaters 08040101 1,546 14 0 9.06

Upper Ouachita 08040102 1,762 24 0 13.62

Little Missouri 08040103 2,097 13 0 6.20

Upper Saline 08040203 1,709 11 0 6.44

Upper White River Basin

Beaver Reservoir 11010001 2,556 1 2 0.39 0.78

James 11010002 1,448 29 0 20.03

Bull Shoals Lake 11010003 2,600 9 0 3.46

Middle White 11010004 1,474 11 0 7.46

Buffalo 11010005 1,342 0 0 0.00

North Fork White 11010006 1,836 1 0 0.54

Little Red 11010014 1,821 9 0 4.94

(continued)

214
Table 4.5—Superfund (NPL) and CERCLIS sites within the aquatic study area, by watershed (continued)

River basin Watershed Superfund CERCLIS NPL site Density, all

Watershed name code (HUC) Area sites sites density sites

Mi2

 - - - - - - Number- - - - - - - - -Sites per1,000 mi2 - - -

Upper Black River Basin

Upper Black 11010007 1,910 19 0 9.95

Current 11010008 2,625 4 0 1.52

Lower Black 11010009 780 4 0 5.13

Spring 11010010 1,217 . 3 2.47 2.47

Eleven Point 11010011 1,202 4 0 3.33

Strawberry 11010012 789 2 0 2.53

NPL = National Priorities List; CERCLIS = Comprehensive Environmental Response, Compensation, and Liability Information System;

HUC = hydrologic unit code.

Source: U.S. EPA (1996a, b).

National Pollutant Discharge Elimination

System (NPDES) Sites

Question 4.5: What are the current status and

potential effects of permitted discharges on

aquatic resources?

All facilities in the United States that release point

source discharges—including wastewater treatment

plants—are required to have a permit under the

NPDES. Such a permit specifies (1) limits for mass (or

concentration) of specific pollutants, (2) monitoring

requirements, and (3) other provisions such as spill

prevention plans. All three specifications can be used to

assess pollution loading and risks.

Data Sources and Methods of Analysis

As mentioned previously, the PCS stores information

on permitted wastewater dischargers—including

location, allowed flows, limits for each allowable

pollutant, monitoring requirements, monitoring reports,

and permit violations. The PCS data base contains

location data for more than 85 percent of the point

sources in the Assessment area; precise locations are

not available for some of the other smaller sources. The

Aquatic Team obtained data from the Better Assessment Science Integrating Point and Nonpoint Sources

(BASINS) CD-ROM (Version 1.0) provided by the

EPA (U.S. EPA 1996a, b).

 Key Findings

 1. About 136 point sources currently discharge

treated wastewater into surface waters of the

Assessment area. Many of these sources with

NPDES permits are considered major facilities

based on volume of discharge and pollutant loadings (concentrations of pollutants in discharged

effluent).

 2. The majority of the permit sources with discharges

greater than 1 million gallons per day (gal/d) are

municipal treatment facilities.

 3. Approximately 200 sewage treatment plants that

serve populations ranging from 1,000 to 132,000

discharge treated water into surface waters of the

Ozark-Ouachita Highlands. Average facility flows

range from 1,000 to 2 million gal/d. Larger municipal sewage treatment plants include those of

Springfield, MO, and Little Rock, AR.

 4. Four industries constitute most of the point source

dischargers: sewage treatment plants, pulp mills,

lead and zinc ore operations, and electrical services.

 5. Of the four types of NPDES facilities that are

ranked as major, the largest number are found in

the Lower Neosho, Upper Black, and James River

watersheds.

 6. Bull Shoals Lake watershed in the Upper White

River Basin has the most NPDES sites in the

Assessment area.

215
Discharge sources were divided into municipal and

industrial categories and further classified by size.

Major point sources are defined as (1) any municipal

facility that has a design flow of at least 1 million

gallons per day (gal/d), a service population of 10,000

persons or more, or a significant impact on water

quality; or (2) any industrial facility that receives a high

score in a rating procedure that is based on flow,

pollutant loadings, potential health impacts, and water

quality factors. All other sources are considered

“minor.”

Patterns and Trends

Table 4.6 shows NPDES sites by (1) major watersheds, (2) watershed size, (3) number of NPDES

sites, and (4) site density/mi2

. The average site density

was 0.024 sites/mi2

. More than 498 facilities currently

discharge effluents into surface waters within the

Assessment area (fig. 4.5). Pollutant loading for a

watershed is not necessarily related to the number of

facilities because a single large facility can make a

greater impact than many small ones. However,

discharges from small facilities into small streams can

also cause significant detrimental impacts. Pollutant

loads from permitted discharges were compiled on a

countywide basis to adjust for the incomplete data that

are associated with some individual discharges. Smaller

facilities are not required to report flow data, so their

loading could not be calculated. The countywide

estimates represent primarily the loads from facilities

with complete data sets. These estimates should

adequately represent the distribution of point source

loads on a regional basis.

About 136 point sources currently discharge

treated wastewater into surface waters of the Assessment area. Many of these sources with NPDES

permits are considered major facilities based on volume

of discharge and pollutant loading (concentrations of

pollutants in discharged effluent). The majority of the

permit sources with discharges greater than 1 million

gal/d are municipal treatment facilities. Approximately

200 sewage treatment plants that serve populations

ranging from 1,000 to 132,000 discharge treated water

into surface waters of the Ozark-Ouachita Highlands.

Average facility flows range from 1,000 to 2 million

gal/d. Larger municipal sewage treatment plants

include those of Springfield, MO, and Little Rock,

AR.

Four industries constitute most of the point sources:

sewage treatment plants, pulp mills, lead and zinc ore

operations, and electrical services. Of the four types of

NPDES facilities that are ranked as major, the largest

number are found in the Lower Neosho, Upper Black,

and James River watersheds.

Bull Shoals Lake watershed in the Upper White

River Basin had the most NPDES sites in the Assessment area. Watersheds having the greatest density of

discharge sites per square mile include the Lower

Arkansas-Maumelle River, Lake O’ the Cherokees,

Big River, Meramec River, James River, Bull Shoals

Lake, and Spring Creek (Neosho-Illinois River Basin).

Watersheds with the lowest density of NPDES sites

include the Fourche La Fave, Kiamichi, Upper Little,

and Eleven Point Rivers (table 4.6 and fig. 4.6).

Implications and Opportunities

The Assessment area is expected to continue to

experience growth in industrial, commercial, and

residential developments, each of which requires

sewage treatment plants and often other waste treatment facilities. Population growth and urbanization

will result in proportional increases in point source

pollutant loads. The lack of complete information for

all point sources complicates assessment and planning

efforts.

As a whole, the Assessment area does not experience widespread impacts due to NPDES permitted

effluents. Localized impacts on the environment may

occur where there are high amounts of outfalls. Procedures to evaluate all permits within a watershed or river

basin will help identify cumulative impacts from all point

and nonpoint sources.

216
Table 4.6—NPDES sites and site density within the aquatic study area

River basin Watershed NPDES

Watershed name code (HUC) Area sites Site density

Mi2 No./mi2

Osage River Basin

H.S. Truman Reservoir 10290105 1,211 15 0.012

Sac 10290106 1,971 20 0.010

Pomme de Terre 10290107 848 15 0.018

South Grand 10290108 2,048 42 0.021

Lake of the Ozarks 10290109 1,385 51 0.037

Niangua 10290110 1,031 29 0.028

Lower Osage 10290111 1,077 35

Gasconade River Basin

Upper Gasconade 10290201 1,788 16 0.009

Big Piney 10290202 756 11 0.015

Lower Gasconade 10290203 1,035 12 0.012

Meramec River Basin

Meramec 07140102 2,160 122 0.056

Bourbeuse 07140103 837 41 0.049

Big 07140104 962 61 0.063

Upper St. Francis River Basin

Upper St. Francis 08020202 1,298 54 0.042

Neosho-Illinois River Basin

Lake O’ the Cherokees 11070206 920 58 0.063

Spring 11070207 2,578 132 0.051

Elk 11070208 1,031 34 0.033

Lower Neosho 11070209 2,210 72 0.033

Illinois 11110103 1,651 15 0.009

Arkansas River Basin

Dirty-Greenleaf 11110102 789 13 0.016

Robert S. Kerr Reservoir 11110104 1,807 35 0.019

Poteau 11110105 1,904 35 0.018

Frog-Mulberry 11110201 1,259 18 0.014

Dardanelle Reservoir 11110202 1,861 24 0.013

Conway-Point Remove 11110203 1,137 20 0.018

Petit Jean 11110204 1,090 13 0.012

Cadron 11110205 769 7 0.009

Fourche La Fave 11110206 1,119 2 0.002

Lower Arkansas-Maumelle 11110207 1,107 86 0.078

Kiamichi-Little River Basin

Kiamichi 11140105 1,821 6 0.003

Upper Little 11140107 1,409 7 0.005

Mountain Fork 11140108 856 8 0.009

Lower Little 11140109 1,975 21 0.011

Ouachita-Saline River Basin

Ouachita Headwaters 08040101 1,546 37 0.024

Upper Ouachita 08040102 1,762 29 0.016

Little Missouri 08040103 2,097 28 0.013

Upper Saline 08040203 1,709 35 0.020

Upper White River Basin

Beaver Reservoir 11010001 2,556 90 0.035

James 11010002 1,448 87 0.060

Bull Shoals Lake 11010003 2,600 138 0.053

Middle White 11010004 1,474 46 0.031

Buffalo 11010005 1,342 12 0.009

North Fork White 11010006 1,836 24 0.013

Little Red 11010014 1,821 44 0.024

(continued)

217
Figure 4.5—Facilities discharging effluents into surface waters of the Assessment area that

have National Pollutant Discharge Elimination System (NPDES) permits (U.S. EPA

1996a, b).

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Arkansas

Missouri

#

NPDES sites

Table 4.6—NPDES sites and site density within the aquatic study area (continued)

River basin Watershed NPDES

Watershed name code (HUC) Area sites Site density

Mi2 No./mi2

Upper Black River Basin

Upper Black 11010007 1,910 79 0.041

Current 11010008 2,625 26 0.010

Lower Black 11010009 780 12 0.015

Spring 11010010 1,217 28 0.023

Eleven Point 11010011 1,202 6 0.005

Strawberry 11010012 789 8 0.010

NPDES = National Pollution Discharge Elimination System; HUC = hydrologic unit code;

mi2

 = square mile.

Source: U.S. EPA (1996a, b).

·

218
Municipal Water Supplies

Question 4.6: How do municipal water facilities

affect water quality within the Assessment area?

Municipal water supplies are essential to the wellbeing and growth of communities in the Assessment

area. Adequate volumes of clean water allow communities to grow; inadequate or contaminated water supplies

can stifle or financially cripple a community. While they

provide for human needs (see Chapter 5 of this report

for a further discussion of water supply and use),

municipal water supplies may also affect aquatic resources. Reservoirs that supply municipal water change

the hydrologic regimes and water quality of streams.

Reservoirs may stop downstream movement of sediment

(sediment will “settle out” in the reservoir bottom),

initiate downstream channel erosion (when they release

water), and influence downstream water temperatures.

Figure 4.6—Density of National Pollutant Discharge Elimination System (NPDES) permits in

the Assessment area (U.S. EPA 1996a, b).

Oklahoma

Arkansas

Missouri

NPDES site density

Above average

Average

Below average

219
Figure 4.7—Locations of public drinking water sources in the Assessment area (U.S. EPA

1996a, b).

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● Drinking water sites

Oklahoma

Arkansas

Missouri

 Key Findings

 1. Municipal water supplies provide over 80 percent

of the drinking water in the Assessment area.

 2. The largest drinking water supplies are located in

the Meramec, Arkansas, Kiamichi, and Upper

White River Basins, which serve about 1.6 million

people.

 3. Smaller water supplies in the Assessment area are

located in less populated watersheds such as the

Upper Black and Upper St. Francis River Basins.

Data Sources and Methods of Analysis

Municipal water supply data were retrieved from the

BASINS Version 1.0 CD ROM (U.S. EPA 1996a, b).

From these data, the Aquatic Team developed a map of

drinking water intake sites. These data may contain

some inaccurate latitudinal and longitudinal data and

incomplete information for some drinking water intakes,

but it was the most complete data set available to the

team.

Patterns and Trends

Figure 4.7 shows the locations for public water

supplies in the Assessment area from which more than

80 percent of the population obtains drinking water. Of

the 152 sites identified, over 87 percent are surface

water sources (table 4.7). The largest drinking water

source is located in the Meramec watershed and

supplies the city of St. Louis.

Water supplies may become stressed for localized

areas in the future during droughts and after further

220
Table 4.7—Number of drinking water sites, sources, volume produced, and population served, by watershed

River basin Watershed Square Drinking Number of Volume in Population

Watershed name code (HUC) miles water sites water sources Mgal/d served

Osage River Basin

H.S. Truman Reservoir 10290105 1,211 3 S(3) 9– 500 6,375

Sac 10290106 1,971 3 S(1) U(2) 7,000– 11,4000 13,175

Pomme de Terre 10290107 848 0 NA

South Grand 10290108 2,048 13 S(13) 22– 891 34,404

Lake of the Ozarks 10290109 1,385 1 U(1) 3 – 100

Niangua 10290110 1,031 0 NA

Lower Osage 10290111 1,077 0 NA

Gasconade River Basin

Upper Gasconade 10290201 1,788 2 S(1) U(1) 0– 33 19,600

Big Piney 10290202 756 1 S(1) — 34,900

Lower Gasconade 10290203 1,035 0 NA

Meramec River Basin

Meramec 07140102 2,160 6 S(4) U(1) G(1) 0– 88,400,000 1,076,172

Bourbeuse 07140103 837 1 S(1) 500– 5,200

Big 07140104 962 1 U(1) 450– 3,225

Upper St. Francis River Basin

Upper St. Francis 08020202 1,298 5 S(4) U(1) 250– 385 9,207

Neosho-Illinois River Basin

Lake O’ the Cherokees 11070206 920 0 NA — —

Spring 11070207 2,578 6 S(5) G(1) 500– 750,000 114,235

Elk 11070208 1,031 0 NA

Lower Neosho 11070209 2,210 9 S(9) 0– 360000 360,000

Illinois 11110103 1,651 7 S(7) 65,000– 90,0000 32,355

Arkansas River Basin

Dirty-Greenleaf 11110102 789 4 U(4 250,000– 730,000 3,098

Robert S. Kerr Reservoir 11110104 1,807 2 S(2) 0– 200,000 15,373

Poteau 11110105 1,904 14 S(14) 110,000– 3,600,000 56,454

Frog–Mulberry 11110201 1,259 6 S(6) 20,000– 15,000,000 71,876

Dardanelle Reservoir 11110202 1,861 4 S(4) 0– 500,000 27,412

Conway-Point Remove 11110203 1,137 0 NA

Petit Jean 11110204 1,090 4 S(4) 200,000– 540,000 5,505

Cadron 11110205 769 1 S(1) 2,900,000– 25,000

Fourche La Fave 11110206 1,119 2 S(1) U(1) 0– 400,000 7,815

Lower Arkansas-Maumelle 11110207 1,107 1 S(1) — 132,483

Kiamichi-Little River Basin

Kiamichi 11140105 1,821 5 S(2) U(3) 36,000– 2,000,000 22,076

Upper Little 11140107 1,409 3 S(2) U(1) 0– 1,000,000 13,068

Mountain Fork 11140108 856 1 S(1) — 3,800

Lower Little 11140109 1,975 3 S(3) 385,000– 1,200,000 8,318

Ouachita-Saline River Basin

Ouachita Headwaters 08040101 1,546 7 S(7) 70,000– 425,000 148,873

Upper Ouachita 08040102 1,762 6 S(6) 100,000– 1,500,000 38,919

Little Missouri 08040103 2,097 2 S(2) 0– 50,000 10,467

Upper Saline 08040203 1,709 4 S(4) 0– 440,000 168,483

Upper White River Basin

Beaver Reservoir 11010001 2,556 4 S(4) 14,400– 13,000,000 79,146

James 11010002 1,448 0 NA

Bull Shoals Lake 11010003 2,600 3 S(3) 26– 1,800,000 17,570

Middle White 11010004 1,474 5 S(5) 143,000– 2,000,000 17,898

Buffalo 11010005 1,342 0 NA

North Fork White 11010006 1,836 0 NA

Little Red 11010014 1,821 7 S(7) 0– 260,000 45,041

(continued)

221
Table 4.7—Number of drinking water sites, sources, volume produced, and population served, by watershed (continued)

River basin Watershed Square Drinking Number of Volume in Population

Watershed name code (HUC) miles water sites water sources Mgal/d served

Upper Black River Basin

Upper Black 11010007 1,910 2 S(2) 250– 2,000 22,100

Current 11010008 2,625 1 U(1) 205– 800

Lower Black 11010009 780 1 S(1) — 7,000

Spring 11010010 1,217 1 S(1) — 496

Eleven Point 11010011 1,202 0 NA

Strawberry 11010012 789 1 U(1) — 309

HUC = hydrologic unit code; Mgal/d = million gallons per day; S = surface; G = ground water; U = unknown; NA = not applicable; — = not available.

Source: U.S. EPA (1996a, b).

increases in urban sprawl and commercial and industrial

development in and around the Assessment area (see

Chapter 5 of this report). Careful planning for future

water supplies will require collaboration among landowners, developers, municipalities, and other watershed

partners to ensure that there are adequate water

supplies as the general population increases and climatological events such as severe droughts place additional

demands on surface and ground water supplies in the

Assessment area.

Implications and Opportunities

Every State is responsible for the protection of

drinking water supplies (both surface and ground water

sources) as an integral part of their watershed management. Strategies for protecting drinking water supplies

are incorporated in the watershed management planning

process in some States. Measures should include ways

to ensure the appropriate level of treatment of continuous discharges as well as contingency measures to

handle spills, emergency bypasses of upstream waste

treatment systems, and periods of low water supply.

Toxic Releases

Question 4.7: What are the current status and

potential effects of toxic pollutants on aquatic

resources in the Assessment area?

As in many other parts of the world, hundreds of

toxic chemicals are stored, transported, used, and

disposed in the Assessment area. Toxic chemicals

include any chemical listed in EPA rules as “Toxic

Chemicals Subject to section 313 of the Emergency

Planning and Community Right-to-Know Act of 1986.”

A toxic substance is a chemical or mixture that may

present unreasonable risk of injury to health or the

environment.

 Key Findings

 1. Densities of toxic release sites are highest in and

near urban areas such as Little Rock, AR; Fort

Smith, AR; Springfield, MO; St.Louis, MO; and

areas that have large industries or concentrations

of industries.

 2. The Spring (Neosho-Illinois River Basin), Lower

Arkansas-Maumelle, James, and Illinois watersheds have the highest number and density of toxic

release sites in the region.

 3. Discharge media for toxic releases include land,

underground, air, water, and off-site transfer. Of

these media, air releases account for 53 percent of

all discharges.

222
Figure 4.8—Toxics Release Inventory (TRI) sites in the Assessment area by watershed, 1992 (U.S. EPA

1996a, b).

Data Sources and Methods of Analysis

The team obtained information on toxic discharges

from the EPA’s Toxics Release Inventory (U.S. EPA

1996a, b). The Toxics Release Inventory (TRI) contains

the annual records of releases of toxic or hazardous

substances to air, water, and land. Reports of quantities

released to water are based on a variety of data gathering techniques, including direct measurements and

estimates provided by the facilities.

Patterns and Trends

Under section 313 of the Emergency Planning and

Community Right-to-Know Act, certain manufacturers

must report annually the amounts of approximately 650

chemicals (in 29 categories) that they release to the air,

land, or water or inject underground. The reports also

include information on amounts transferred to off-site

locations for treatment or disposal. The locations of

toxic release sites in the aquatic study area are displayed (fig. 4.8) from the BASINS data (U.S. EPA

1996a, b). Densities of toxic release sites are highest in

and near urban areas such as Little Rock, AR; Fort

Smith, AR; Springfield, MO; St. Louis, MO, and areas

that have large industries or concentrations of industries.

The Spring (Neosho-Illinois River Basin), Lower

Arkansas-Maumelle, James, and Illinois watersheds

have the highest number and density of toxic release

sites in the region (table 4.8). Discharge media for toxic

releases include air, land, water, and off-site transfer. Of

these media, air releases account for 53 percent of all

discharges.

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● Toxics Release Inventory

sites

223
Table 4.8—Number and density of toxic release sites and discharge areas in the aquatic study area

 Number of discharge areas to

River basin Watershed Number Sites per

Watershed name code (HUC) of sitesa square mile Air Land Water Off-site

Osage River Basin

H.S. Truman Reservoir 10290105 1 0.001 1

Sac 10290106 11 0.006 7 2 1 3

Pomme de Terre 10290107 7 0.008 6 1 4

South Grand 10290108 6 0.003 2 3

Lake of the Ozarks 10290109 6 0.004 6 4

Niangua 10290110 2 0.002 1 1

Lower Osage 10290111 4 0.004 3 2

Gasconade River Basin

Upper Gasconade 10290201 6 0.003 5 1

Big Piney 10290202 6 0.008 2 1

Lower Gasconade 10290203 0

Meramec River Basin

Meramec 07140102 22 0.010 22 1 17

Bourbeuse 07140103 12 0.014 12 2 9

Big 07140104 2 0.002 2 1 1 2

Upper St. Francis River Basin

Upper St. Francis 08020202 2 0.002 2 1 1 2

Neosho-Illinois River Basin

Lake O’ the Cherokees 11070206 5 0.006 5 1 2

Spring 11070207 73(2) 0.028 49 4 7 30

Elk 11070208 4 0.004 4 1 2

Lower Neosho 11070209 9 0.004 9 1 1 5

Illinois 11110103 35 0.021 35 2 2 5

Arkansas River Basin

Dirty-Greenleaf 11110102 3 0.004 3 1 1 2

Robert S. Kerr Reservoir 11110104 16 0.009 16 4 4 13

Poteau 11110105 19 0.010 16 1 13

Frog-Mulberry 11110201 3 0.002 3 1 1 3

Dardanelle Reservoir 11110202 10 0.005 10 1 3

Conway-Point Remove 11110203 0

Petit Jean 11110204 4 0.004 4 2 4

Cadron 11110205 1 0.001 1

Fourche La Fave 11110206 0

Lower Arkansas-Maumelle 11110207 56(1) 0.051 56 2 3 31

Kiamichi-Little River Basin

Kiamichi 11140105 1 0.001 1 1

Upper Little 11140107 4 0.003 4 1 1

Mountain Fork 11140108 5 0.006 3 3

Lower Little 11140109 10 0.005 7 2 2 5

Ouachita-Saline River Basin

Ouachita Headwaters 08040101 11 0.007 9 1 2 6

Upper Ouachita 08040102 10 0.006 7 3

Little Missouri 08040103 5(1) 0.002 2 1 2

Upper Saline 08040203 13 0.008 8 1 2 6

Upper White River Basin

Beaver Reservoir 11010001 21(1) 0.008 14 1 12

James 11010002 48 0.033 34 1 2 27

Bull Shoals Lake 11010003 13 0.005 11 1 9

Middle White 11010004 13 0.009 11 2 2 8

Buffalo 11010005 1 0.001

North Fork White 11010006 1 0.001 1 1

Little Red 11010014 13 0.007 10 1 12

(continued)

224
Table 4.8—Number and density of toxic release sites and discharge areas in the aquatic study area (continued)

 Number of discharge areas to

River basin Watershed Number Sites per

Watershed name code (HUC) of sitesa square mile Air Land Water Off-site

Upper Black River Basin

Upper Black 11010007 6 0.003 5 4

Current 11010008 5(1) 0.002 3 1

Lower Black 11010009 3 0.004 3 3

Spring 11010010 4 0.003 3 2

Eleven Point 11010011 0

Strawberry 11010012 0

HUC = hydrologic unit code.

a Number of closed sites, if any, shown in parentheses.

Source: U.S. EPA (1996a, b).

For the most current information on chemical exposure, the Right-to-Know Computer Network (RTK

NET) has TRI data from 1987 through 1996; see the

Web site at <http://www.rtk.net/datadoc/tris.html>.

Health factsheets for a variety of chemical data are

available on the Internet, including the complete text and

tables from the public data release documents at EPA’s

Envirofacts Web site: <http://www.epa.gov/enviro/

index_java.html> or at <http://www.epa.gov/chemfact>.

The latter Web site includes information on 40 selected

TRI chemicals and describes (1) how citizens might be

exposed to these chemicals, (2) how exposure to them

might affect the public and the environment, (3) what

happens to the chemicals in the environment, (4) who

regulates them, and (5) who to contact for additional

information. A list of TRI chemicals classified as

carcinogens by either the Occupational Safety and

Health Administration (OSHA) or the EPA is also

included, and the Web site explains the basis of the

classifications.

The OSHA carcinogens are limited to 0.1 percent

concentration, while the EPA uses 1 percent. Amounts

of TRI chemicals that are present below the concentration limits in mixtures do not have to be included in

threshold and release calculations. The EPA provides

answers to frequently asked questions about health

effects of 60 hazardous substances in a Toxic Substance and Disease Registry (available at <http://

atsdr1.atsdr.cdc.gov:8080/toxfaq.html>). About 50 of

these chemicals are also TRI chemicals. It is beyond

the scope of this report to identify and characterize toxic

compounds in watersheds of the Assessment area or to

estimate exposure and effects of toxins upon human

health and the environment.

Implications and Opportunities

Because the manufacture of most bioaccumulative

chemicals (substances that increase in concentrations in

living organisms as they take in contaminated air, water,

or food because the substances are very slowly metabolized or excreted) has either been banned or is now

strictly regulated, levels of these chemicals should

decrease in the Assessment area over time. However,

toxic chemicals often persist for long periods in aquatic

environments, and opportunities exist to improve future

monitoring of toxins in water and aquatic biota. Watersheds with potentially high impacts from toxins deserve

special attention.

TRI reports reflect releases of chemicals, not

exposures of the public to those chemicals. Release

estimates alone are not sufficient to determine exposure

or to calculate potential adverse effects on human

health and the environment. Release estimates are

aggregate annual estimates and do not provide information about peak concentrations. Estimating and measuring release amounts in complex manufacturing processes is not an exact science; estimation techniques

need further research and development.

Toxic waste discharges are likely to continue in the

Assessment area. Existing regulatory requirements

should control point sources of toxic chemicals including

225
follow up on the progress of individual control strategies

for those facilities identified under section 304(l) regulations. Although TRI discharges continue, release

amounts have declined yearly since the implementation

of the TRI program.

Nonpoint Sources

Nonpoint sources of water pollutants are nonidentifiable, diffuse conveyances from which contaminants enter and impair a stream; they often originate

from diffuse sources. Nonpoint sources include activities associated with construction, agriculture, or silviculture. This section discusses many of the nonpoint

sources within the Assessment area and includes roads

and highways, agriculture and silviculture, pesticides,

fertilizers, urbanization, mineral extraction, and introduced species.

Roads and Highways

Question 4.8: What are the current status and

potential effects of roads and highways on

aquatic resources in the Highlands?

Roads, highways, and bridges contribute measurable

amounts of pollutants to the Nation’s waters (U.S. EPA

1995). The impervious surface of roads and highways

prevents the infiltration of rainfall and causes runoff to

increase. Runoff may carry sediments, nutrients, oil,

grease, gasoline, metals, salts, and other pollutants

generated by vehicular traffic and road maintenance.

When the polluted runoff enters a stream, water quality

can be degraded. Obviously, roads and highways near

streams, lakes, and rivers have the greatest potential to

deposit pollutants in water bodies.

Sediment is one of the primary pollutants from

gravel and dirt roads. Periodic maintenance of the

roadbeds and ditches of these roads exposes soil to

erosion (as does neglecting road maintenance). The

increase in runoff sediment caused by road construction and maintenance can cause physical changes in the

aquatic habitat (MacDonald and others 1991). Sediment loads can affect channel shape, sinuosity, the ratio

of stream length to valley length, and the relative

balance between pools and riffles. Increased sediment

can also alter the quantity and quality of habitats for

fish and invertebrates.

Road construction that creates a greater impervious

surface area and/or interrupts the subsurface lateral

flow of water can increase peak runoff flows

(MacDonald and others 1991). Careful layout and

construction of roads can minimize changes in the

volume and route of peak flows. When roads occupy a

significant proportion of a watershed, total water yield

and flow timing will be observably affected.

Places where roads cross streams can be barriers to

fish movement and gravel distribution in streams. Filipek

(1993) indicates that in the Ozark and Ouachita Mountains, low water bridges and culverts affect not only fish

migration (by impeding fish movement directly or by

creating new gravel bars that impede fish) but also

affect gravel distribution in these streams.

Riparian areas are transition areas between the

uplands and water bodies. The riparian area filters

sediments and absorbs nutrients from upland runoff to

varying degrees before it reaches streams. Road

construction and maintenance within riparian zones,

however, can reduce these filtering and absorption

processes.

 Key Findings

 1. All watersheds in the Assessment area have road

segments within 100 feet of streams.

 2. The Upper Black River, Bull Shoals Lake, Current

River, Beaver Reservoir, and Illinois River watersheds have the most road miles within riparian

areas in the Assessment area.

 3. Class 2 and 3 roads (State highways and county

roads) have the highest number of miles within

Highlands riparian areas.

 4. Class 3 roads (county and national forest roads)

have the most miles within riparian areas in national

forests.

Data Sources and Methods of Analysis

Data sources are the GIS roads and streams layers.

The Aquatic Team built the GIS road layer using

1:100,000 Digital Line Graph (DLG) files. These were

226
assembled in three files for the Assessment area, based

on road size and use:

• Class 1 includes Federal interstate highways;

• Class 2 consists of State highways;

• Class 3 includes paved, gravel, and dirt county roads.

The team built the GIS stream layer using the EPA’s

RF3, which is based on the 1:100,000 scale DLG data.

Streams in some portions of the stream layer were not

mapped originally at the same density (see “Riparian

Areas” in Chapter 2 of this report for a further discussion of the stream layer). To estimate the impacts of

roads on Highlands aquatic resources, the team used a

buffer of 100 feet (ft) on either side of each road

segment in each of the three road files. Then the team

intersected the stream layer with the buffered road layer.

Next, the team totaled the lengths of streams within

these buffers for each watershed. Finally, the team

conducted analyses by road class and by watershed.

Patterns and Trends

Table 4.9 displays miles and classes of roads found

within riparian areas in the aquatic study area. (Class 1

is Federal interstate highways, Class 2 is State highways, and Class 3 is county roads.) These lands adjacent to streams or lakes can lessen the effects of

disturbances in the watersheds above them. Riparian

areas cannot make up for mismanagement of the

uplands, but they can more readily reduce the impacts to

water bodies when uplands are managed properly.

All Assessment area watersheds have roads of varying

classes within 100 ft of streams. The Osage, NeoshoIllinois, Arkansas, Upper White, and Upper Black River

Basins have the most road miles within riparian areas.

Within these river basins and in descending order, the

Upper Black, Bull Shoals Lake, Current, Beaver Reservoir, and Illinois watersheds have the most road miles

within riparian areas in the Assessment area (table 4.9).

For this analysis, the riparian area is defined as the

area within 100 ft of streams. Road segments within

100 ft of streams have a greater potential to degrade

water quality than road segments more than 100 ft from

streams. “Studies in the Southern Appalachian Mountains have shown that a forested buffer that is 100 ft

wide will trap most of the sediment from a newly

constructed graveled road” (Swift 1986, SAMAB

1996).

Table 4.10 displays the miles and types of roads

found within riparian areas on national forest lands

within the Assessment area (there are no Class 1

roads). Class 3 roads have the greatest potential to

degrade water quality because they have the most road

miles within Highlands’ riparian areas (306 mi of roads

compared with 133 mi of Class 2 roads). In addition,

Class 3 roads are often unsurfaced (dirt), which allows

soil to wash from the road’s surface into streams.

Implications and Opportunities

An opportunity exists for the Forest Service, States,

and counties to work together to reduce the impact of

road construction and maintenance on aquatic resources. Simple but effective measures are available to

control road runoff and sediment. Examples of these

measures are sediment basins and waterbars.

Opportunities also exist to locate new roads and

relocate old roads outside the riparian area. The riparian

area can filter sediments, absorb nutrients, and delay or

catch other pollutants from road runoff. Damage to the

riparian area should be prevented or minimized so that

the buffering capacity of the riparian area can be

maintained.

Road crossings can be designed so that fish and

stream gravel can pass freely instream. The opportunity

to design road crossings so that fish and stream gravel

can pass freely is increasingly being exercised. As old

stream crossings that function as fish and gravel

barriers deteriorate, there will be more opportunities to

replace them with crossings that allow free passage of

fish and gravel.

227
Table 4.9—Miles of roads in riparian areas of the aquatic study area watersheds, by road class

River basin Watershed Class 1 (Federal Class 2 (State Class 3 (paved, gravel

Watershed name code (HUC) interstate highways) highways) and dirt county roads) Total

 - - - - - - - - - - - - - - - - - - - - - - - - - - - Miles - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Osage River Basin

H.S. Truman Reservoir 10290105 0.1 51.2 26.2 77.5

Sac 10290106 0.8 108.8 51.3 160.9

Pomme de Terre 10290107 0.3 45.9 20.7 66.9

South Grand 10290108 0 128.4 57.6 186.0

Lake of the Ozarks 10290109 0.4 75.3 186.3 262.0

Niangua 10290110 0.7 50.0 46.5 97.2

Lower Osage 10290111 0 42.9 27.9 70.8

Gasconade River Basin

Upper Gasconade 10290201 1.8 103.8 69.2 174.8

Big Piney 10290202 0.2 47.3 41.3 88.8

Lower Gasconade 10290203 0.8 38.6 38.3 77.7

Meramec River Basin

Meramec 07140102 1.9 76.7 170.1 248.7

Bourbeuse 07140103 2.6 37.5 18.3 58.4

Big 07140104 0 55.3 102.6 157.9

Upper St. Francis River Basin

Upper St. Francis 08020202 0 77.3 89.1 166.4

Neosho-Illinois River Basin

Lake O’ the Cherokees 11070206 0.3 44.1 34.9 79.3

Spring 11070207 1.3 101.7 38.4 141.4

Elk 11070208 0 95.5 43.8 139.3

Lower Neosho 11070209 0.3 122.1 90.5 212.9

Illinois 11110103 0.2 158.4 113.4 272.0

Arkansas River Basin

Dirty-Greenleaf 11110102 3.2 58.0 31 92.2

Robert S. Kerr Reservoir 11110104 4.0 107.3 77.4 188.7

Poteau 11110105 0.2 106.1 120.8 227.1

Frog-Mulberry 11110201 1.8 48.0 85.7 135.5

Dardanelle Reservoir 11110202 3.0 101.6 97.4 202.0

Conway-Point Remove 11110203 1.5 57.2 59.8 118.5

Petit Jean 11110204 0 47.9 58.6 106.5

Cadron 11110205 0.2 54.3 27.0 81.5

Fourche La Fave 11110206 0 49.5 112.1 161.6

Lower Arkansas-Maumelle 11110207 4.3 34.8 142.3 181.4

Kiamichi-Little River Basin

Kiamichi 11140105 0.2 65.9 48.4 114.5

Upper Little 11140107 0 30.7 59.7 90.4

Mountain Fork 11140108 0 18.7 54.9 73.6

Lower Little 11140109 0 63.4 72.7 136.1

Ouachita-Saline River Basin

Ouachita Headwaters 08040101 0 108.9 122.8 231.7

Upper Ouachita 08040102 1.7 103.1 91.1 195.9

Little Missouri 08040103 1.8 90.4 103.8 196.0

Upper Saline 08040203 1.5 97.7 85.0 184.2

Upper White River Basin

Beaver Reservoir 11010001 0 136.9 140.8 277.7

James 11010002 0.1 123.1 87.9 211.1

Bull Shoals Lake 11010003 0.2 146.1 146.6 292.9

Middle White 11010004 0 65.8 100.2 166.0

Buffalo 11010005 0 49.8 69.5 119.3

North Fork White 11010006 0 99.0 94.1 193.1

Little Red 11010014 0.9 60.3 82.0 143.2

228
Agriculture and Silviculture

Question 4.9: What are the current status and

estimated effects of potential erosion from agriculture and silviculture on aquatic resources

within the Assessment area?

Agriculture and silviculture are sources of sediment,

which is a major nonpoint source pollutant of aquatic

habitats. Sediment creates turbidity, fills in stream channels and reservoirs, changes aquatic habitat, and carries

nutrients into streams. In 1991 and 1992, States attributed

41 percent of their nonpoint source pollution to agriculture

and 3 percent to silviculture (U.S. EPA 1992a).

 Key Findings

 1. Total potential erosion declined in more than half of

the watersheds in the Assessment area for the 3

years studied (1982, 1987, and 1992).

 2. The South Grand watershed had the highest

average potential erosion rate in 1992.

 3. Most of the cropland potential erosion as a percent

of total potential erosion came from watersheds

along the eastern and western boundaries of the

Assessment area for the 3 years studied.

 4. The Fourche La Fave, Ouachita Headwaters, and

Upper Little River watersheds had the lowest

average potential erosion rates for the 3 years

studied.

 5. Forest potential erosion as a percent of total potential

erosion was 3 percent or less for most of the

Assessment area watersheds for the 3 years studied.

 6. In 1982, 1987, and 1992, watersheds with the

highest forest potential erosion as a percent of total

potential erosion were in the southern part of the

Assessment area.

 7. The category with the highest potential erosion in

most Assessment area watersheds for the 3 years

studied was pasture lands.

 8. Most watersheds in the Assessment area had no

appreciable potential erosion from rangelands.

 9. In more than half of the Assessment area watersheds, potential erosion rates from “other” lands

were 2 percent or less of total potential erosion.

Table 4.10—Miles of roads within riparian areas on national

forests in the Assessment area, by road classa

National forest Class 1 Class 2 Class 3 Total

 - - - - - - - - - - - - - Miles - - - - - - - - - - - - -

Ouachita 0 78 171 249

Ozark 0 25 64 89

Mark Twain 0 30 70 101

Total 0 133 306 439

a Class 1 = Federal interstate highways; Class 2 = State highways;

Class 3 = county roads.

Table 4.9—Miles of roads in riparian areas of the aquatic study area watersheds, by road class (continued)

River basin Watershed Class 1 (Federal Class 2 (State Class 3 (paved, gravel

Watershed name code (HUC) interstate highways) highways) and dirt county roads) Total

 - - - - - - - - - - - - - - - - - - - - - - - - - - - Miles - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Upper Black River Basin

Upper Black 11010007 0 133.7 161.3 295.0

Current 11010008 0 123.2 166.4 289.6

Lower Black 11010009 0 48.0 38.9 86.9

Spring 11010010 0 60.2 46.7 106.9

Eleven Point 11010011 0 49.2 52.2 101.4

Strawberry 11010012 0 31.1 28.1 59.2

Total 36.3 3,830.7 3,931.6 7,798.6

HUC = hydrologic unit code.

229
“Potential erosion estimates” are tentative predictions

of onsite erosion of agricultural and forested lands. Much

of the estimated eroded soil is trapped by vegetation or in

depressions in the land. A portion of the estimated

eroded soil could enter water bodies and become

sediment. Land management practices can influence

(positively or negatively) the amount of eroded soil that

reaches water bodies. Best management practices

(BMP’s) and conservation measures can reduce the

amount of eroded soil that reaches water bodies. (See

Chapter 3 of this report for a discussion of BMP’s.)

Data Sources and Methods of Analysis

The team collected estimates of potential erosion

for Assessment area watersheds from the National

Resources Inventory (NRI), which is conducted by the

Natural Resources Conservation Service (USDA NRCS

1997). The NRI is based on a 0.7 percent sample of all

non-Federal rural land in the Nation. Categories of

similar land uses were grouped together into a sampling

universe (clusters of sites by land use that make data

extraction easier). Primary sampling units (PSU’s) were

randomly selected within each sampling universe. Within

each PSU, three sampling points were selected. The

data from each sampling point were multiplied by the

number of acres per sampling point in the sampling

universe and then summed to give totals for the universe.

Natural Resources Conservation Service personnel

made estimates of potential erosion using the Universal

Soil Loss Equation at sampling points where agriculture

was the primary land use. Agency personnel return to the

sampling points every 5 years to collect data about land

uses and to make estimates of potential erosion. Data

from the 1982, 1987, and 1992 NRI inventories were

used in this analysis. Because the Natural Resources

Conservation Service did not make potential erosion

estimates where forestry was the primary land use, the

Aquatic Team provided such estimates for this report.

Patterns and Trends

Table 4.11 displays potential erosion in the aquatic

study area by watershed for 1982, 1987, and 1992 using

NRI data. Average potential erosion declined in more

than half of the Assessment area watersheds for the 3

years studied.

Figure 4.9 shows average potential erosion by

watershed for 1992. The South Grand watershed had

the highest average potential erosion (2.44 thousand

tons/mi2

), and the Spring watershed in the NeoshoIllinois River Basin had the second highest average

potential erosion (0.93 thousand tons/mi2

). The Fourche

La Fave, Ouachita Headwaters, and Upper Little

watersheds had the lowest average potential erosion

rates for the years studied (table 4.11).

During 1982, 1987, and 1992, most of the potential

cropland erosion as a percent of TPE came from

watersheds along the eastern and western boundaries of

the Assessment area. Some of the watersheds with a

high percentage of TPE from cropland during 1992

were the Upper Black (91 percent), Lower ArkansasMaumelle (87 percent), Lower Black (69 percent),

Harry S. Truman Reservoir (69 percent), Conway-Point

Remove (63 percent), and Lower Neosho (60 percent).

The Harry S. Truman Reservoir, Lower ArkansasMaumelle, Upper Black, and Lower Black watersheds

experienced reductions in potential cropland erosion as a

percent of TPE for the 3 years studied, while the Lower

Neosho watershed experienced a slight increase in

potential erosion of croplands as a percent of TPE

during the same period.

Potential erosion of forest lands was 3 percent of

TPE or less for most of the Assessment area watersheds for the years studied. Watersheds with the highest

potential forest erosion were in the southern part of the

Assessment area. The Fourche La Fave (13 percent),

Upper Little River (10 percent), and Upper Ouachita (8

percent) watersheds had the highest percentages of

potential forest erosion in 1992.

Pasture lands had the highest potential erosion rates

in most Assessment area watersheds for the 3 years

studied. The Big Piney (99 percent), Spring (Upper

Black River Basin, 97 percent), Buffalo (94 percent),

Meramec (87 percent), Dardanelle Reservoir (81

percent), and Elk (79 percent) watersheds had some of

the highest percentages of TPE in 1992. Pasture

potential erosion increased for 1982, 1987, and 1992 in

all of the watersheds listed above.

While most of the Assessment area watersheds had

no potential rangeland erosion, some watersheds in the

central and southwestern parts of the Assessment area

did. The Kiamichi (20 percent), Bull Shoals Lake (18

percent), and North Fork White (13 percent) watersheds had the highest rangeland potential erosion rates

in 1992. Rangeland potential erosion in 1992 dropped

below the 1982 levels in all three watersheds.

230
Table 4.11—Potential erosion rates in the aquatic study area, by land use category and year (1992, 1987, 1982)

Watershed Total Average Potential Potential Potential Potential Potential

River basin code potential potential erosion from erosion from erosion from erosion from erosion from

Watershed name (HUC) erosion erosion croplands forest lands pasture lands rangelands other lands

k tons k tons/mi2

 k tons % k tons % k tons % k tons % k tons %

1992

Osage River Basin

H.S. Truman Reservoir 10290105 820 0.68 569 69 4 1 110 13 1 0 136 17

Sac 10290106 1,005 0.51 372 37 7 1 606 60 2 0 19 2

Pomme de Terre 10290107 246 0.29 44 18 3 1 188 77 0 0 11 4

South Grand 10290108 5,001 2.44 2,756 55 3 0 330 7 0 0 1,913 38

Lake of the Ozarks 10290109 421 0.30 65 16 11 3 345 82 0 0 0 0

Niangua 10290110 297 0.29 79 27 8 3 210 71 0 0 0 0

Lower Osage 10290111 527 0.49 89 17 7 1 428 81 0 0 4 1

Gasconade River Basin

Upper Gasconade 10290201 1,211 0.68 60 5 8 1 1,129 93 0 0 14 1

Big Piney 10290202 311 0.41 2 1 3 1 306 99 0 0 0 0

Lower Gasconade 10290203 395 0.38 39 10 7 2 343 87 0 0 7 2

Meramec River Basin

Meramec 07140102 776 0.36 84 11 16 2 675 87 0 0 0 0

Bourbeuse 07140103 342 0.41 136 40 4 1 197 58 0 0 4 1

Big 07140104 380 0.40 19 5 7 2 311 82 0 0 42 11

Upper St. Francis River Basin

Upper St. Francis 08020202 388 0.30 59 15 9 2 321 83 0 0 0 0

Neosho-Illinois River Basin

Lake O’ the Cherokees 11070206 631 0.69 344 55 3 0 169 27 9 1 106 17

Spring 11070207 2,388 0.93 1,582 66 5 0 369 15 35 1 396 17

Elk 11070208 674 0.65 125 19 5 1 534 79 0 0 9 1

Lower Neosho 11070209 831 0.38 495 60 8 1 208 25 102 12 18 2

Illinois 11110103 538 0.33 51 10 9 2 389 72 10 2 78 15

Arkansas River Basin

Dirty-Greenleaf 11110102 673 0.85 183 27 3 0 408 61 80 12 0 0

Robert S. Kerr Reservoir 11110104 773 0.43 265 34 10 1 345 45 71 9 82 11

Poteau 11110105 574 0.30 37 7 10 2 383 67 18 3 125 22

Frog-Mulberry 11110201 587 0.47 205 35 4 1 378 64 0 0 0 0

Dardanelle Reservoir 11110202 844 0.45 94 11 7 1 686 81 0 0 58 7

Conway-Point Remove 11110203 585 0.51 369 63 6 1 210 36 0 0 0 0

Petit Jean 11110204 344 0.32 27 8 5 1 312 91 0 0 0 0

Cadron 11110205 285 0.37 101 35 3 1 161 57 0 0 19 7

Fourche La Fave 11110206 34 0.03 8 23 4 13 21 64 0 0 0 0

Lower Arkansas-Maumelle 11110207 597 0.54 517 87 5 1 8 1 0 0 67 11

Kiamichi-Little River Basin

Kiamichi 11140105 644 0.35 9 1 14 2 494 77 128 20 0 0

Upper Little 11140107 136 0.10 0 0 14 10 116 85 0 0 7 5

Mountain Fork 11140108 117 0.14 0 0 7 6 95 81 0 0 15 13

Lower Little 11140109 236 0.12 0 0 17 7 188 80 0 0 31 13

Ouachita-Saline River Basin

Ouachita Headwaters 08040101 93 0.06 0 0 7 7 86 93 0 0 0 0

Upper Ouachita 08040102 287 0.16 140 49 23 8 107 37 0 0 18 6

Little Missouri 08040103 319 0.15 89 28 20 6 188 59 0 0 23 7

Upper Saline 08040203 628 0.37 38 6 18 3 35 6 0 0 536 85

Upper White River Basin

Beaver Reservoir 11010001 955 0.37 7 1 15 2 821 86 111 12 0 0

James 11010002 974 0.67 132 14 5 1 821 84 0 0 16 2

Bull Shoals Lake 11010003 1,951 0.75 45 2 15 1 1,509 77 350 18 33 2

Middle White 11010004 509 0.35 137 27 10 2 330 65 31 6 0 0

(continued)

231
Table 4.11—Potential erosion rates in the aquatic study area, by land use category and year (1992, 1987, 1982) (continued)

Watershed Total Average Potential Potential Potential Potential Potential

River basin code potential potential erosion from erosion from erosion from erosion from erosion from

Watershed name (HUC) erosion erosion croplands forest lands pasture lands rangelands other lands

k tons k tons/mi2

 k tons % k tons % k tons % k tons % k tons %

1992 (continued)

Upper White River Basin

(continued)

Buffalo 11010005 601 0.45 2 0 9 1 563 94 0 0 27 4

North Fork White 11010006 962 0.52 126 13 11 1 679 71 125 13 21 2

Little Red 11010014 408 0.22 69 17 14 3 223 55 0 0 103 25

Upper Black River Basin

Upper Black 11010007 1,028 0.54 938 91 12 1 78 8 0 0 0 0

Current 11010008 800 0.30 305 38 19 2 476 59 0 0 0 0

Lower Black 11010009 642 0.82 446 69 3 1 173 27 0 0 20 3

Spring 11010010 573 0.47 5 1 7 1 556 97 0 0 5 1

Eleven Point 11010011 470 0.39 21 4 7 1 428 91 0 0 14 3

Strawberry 11010012 454 0.58 31 7 5 1 362 80 54 12 2 0

1987

Osage River Basin

H.S. Truman Reservoir 10290105 1,127 0.93 881 78 4 0 108 10 1 0 133 12

Sac 10290106 1,454 0.74 580 40 6 0 812 56 2 0 55 4

Pomme de Terre 10290107 364 0.43 130 36 3 1 211 58 0 0 21 6

South Grand 10290108 6,100 2.98 3,795 62 3 0 378 6 0 0 1,924 32

Lake of the Ozarks 10290109 546 0.39 128 23 10 2 408 75 0 0 0 0

Niangua 10290110 307 0.30 58 19 8 3 241 78 0 0 0 0

Lower Osage 10290111 504 0.47 94 19 7 1 399 79 0 0 4 1

Gasconade River Basin

Upper Gasconade 10290201 1,585 0.89 79 5 8 0 1,484 94 0 0 14 1

Big Piney 10290202 178 0.24 7 4 3 2 168 95 0 0 0 0

Lower Gasconade 10290203 554 0.54 194 35 7 1 347 63 0 0 7 1

Meramec River Basin

Meramec 07140102 879 0.41 192 22 16 2 635 72 0 0 36 4

Bourbeuse 07140103 541 0.65 307 57 4 1 225 42 0 0 4 1

Big 07140104 462 0.48 48 10 7 1 383 83 0 0 24 5

Upper St. Francis River Basin

Upper St. Francis 08020202 305 0.23 6 2 9 3 290 95 0 0 0 0

Neosho-Illinois River Basin

Lake O’ the Cherokees 11070206 709 0.77 570 80 3 0 106 15 19 3 11 2

Spring 11070207 3,082 1.20 2,131 69 5 0 468 15 33 1 445 14

Elk 11070208 464 0.45 149 32 5 1 301 65 0 0 9 2

Lower Neosho 11070209 799 0.36 475 59 8 1 209 26 107 13 0 0

Illinois 11110103 457 0.28 50 11 9 2 330 72 30 7 37 8

Arkansas River Basin

Dirty-Greenleaf 11110102 763 0.97 271 36 2 0 409 54 80 11 0 0

Robert S. Kerr Reservoir 11110104 954 0.53 285 30 10 1 300 31 94 10 265 28

Poteau 11110105 413 0.22 27 7 10 2 208 50 42 10 125 30

Frog-Mulberry 11110201 625 0.50 266 42 4 1 315 50 7 1 33 5

Dardanelle Reservoir 11110202 871 0.47 117 13 7 1 689 79 0 0 58 7

Conway-Point Remove 11110203 657 0.58 431 66 6 1 211 32 0 0 9 1

Petit Jean 11110204 402 0.37 41 10 5 1 333 83 0 0 23 6

Cadron 11110205 240 0.31 110 46 3 1 116 48 0 0 11 5

Fourche La Fave 11110206 63 0.06 34 54 4 7 24 39 0 0 0 0

Lower Arkansas-Maumelle 11110207 478 0.43 422 88 6 1 8 2 0 0 43 9

(continued)

232
Table 4.11—Potential erosion rates in the aquatic study area, by land use category and year (1992, 1987, 1982) (continued)

Watershed Total Average Potential Potential Potential Potential Potential

River basin code potential potential erosion from erosion from erosion from erosion from erosion from

Watershed name (HUC) erosion erosion croplands forest lands pasture lands rangelands other lands

k tons k tons/mi2

 k tons % k tons % k tons % k tons % k tons %

1987 (continued)

Kiamichi-Little River Basin

Kiamichi 11140105 461 0.25 6 1 14 3 286 62 155 34 0 0

Upper Little 11140107 80 0.06 0 0 14 17 66 83 0 0 0 0

Mountain Fork 11140108 117 0.14 0 0 7 6 95 81 0 0 15 13

Lower Little 11140109 224 0.11 18 8 17 8 190 85 0 0 0 0

Ouachita-Saline River Basin

Ouachita Headwaters 08040101 96 0.06 0 0 7 7 90 93 0 0 0 0

Upper Ouachita 08040102 215 0.12 127 59 23 11 65 30 0 0 0 0

Little Missouri 08040103 402 0.19 129 32 20 5 220 55 0 0 33 8

Upper Saline 08040203 2,263 1.32 31 1 18 1 76 3 0 0 2,138 94

Upper White River Basin

Beaver Reservoir 11010001 917 0.36 9 1 15 2 774 84 118 13 0 0

James 11010002 1,336 0.92 221 17 5 0 1,051 79 0 0 59 4

Bull Shoals Lake 11010003 1,765 0.68 59 3 14 1 1,327 75 334 19 32 2

Middle White 11010004 690 0.47 185 27 10 1 282 41 113 16 101 15

Buffalo 11010005 758 0.56 5 1 9 1 691 91 0 0 53 7

North Fork White 11010006 1,002 0.55 105 11 11 1 754 75 111 11 20 2

Little Red 11010014 619 0.34 352 57 14 2 200 32 0 0 54 9

Upper Black River Basin

Upper Black 11010007 1,318 0.69 1,187 90 12 1 88 7 0 0 30 2

Current 11010008 1,003 0.38 325 32 19 2 658 66 0 0 0 0

Lower Black 11010009 774 0.99 585 76 3 0 171 22 0 0 14 2

Spring 11010010 416 0.34 4 1 8 2 399 96 0 0 5 1

Eleven Point 11010011 579 0.48 37 6 7 1 535 92 0 0 0 0

Strawberry 11010012 316 0.40 32 10 5 2 263 83 4 1 12 4

1982

Osage River Basin

H.S. Truman Reservoir 10290105 1,474 1.22 1,232 84 4 0 127 9 4 0 108 7

Sac 10290106 1,655 0.84 591 36 6 0 999 60 9 1 50 3

Pomme de Terre 10290107 349 0.41 88 25 2 1 254 73 0 0 5 1

South Grand 10290108 7,326 3.58 3,750 51 2 0 495 7 0 0 3,078 42

Lake of the Ozarks 10290109 638 0.46 90 14 10 2 538 84 0 0 0 0

Niangua 10290110 288 0.28 45 16 8 3 234 81 0 0 0 0

Lower Osage 10290111 613 0.57 185 30 6 1 418 68 0 0 3 1

Gasconade River Basin

Upper Gasconade 10290201 976 0.55 71 7 8 1 883 90 0 0 14 1

Big Piney 10290202 181 0.24 4 2 3 2 174 96 0 0 0 0

Lower Gasconade 10290203 621 0.60 219 35 6 1 395 64 0 0 0 0

Meramec River Basin

Meramec 07140102 1,210 0.56 317 26 16 1 877 72 0 0 0 0

Bourbeuse 07140103 664 0.79 404 61 4 1 252 38 0 0 4 1

Big 07140104 567 0.59 238 42 7 1 322 57 0 0 0 0

Upper St. Francis River Basin

Upper St. Francis 08020202 510 0.39 57 11 9 2 444 87 0 0 0 0

Neosho-Illinois River Basin

Lake O’ the Cherokees 11070206 603 0.66 456 76 3 0 137 23 6 1 0 0

Spring 11070207 3,341 1.30 2,363 71 4 0 611 18 32 1 331 10

(continued)

233
Table 4.11—Potential erosion rates in the aquatic study area, by land use category and year (1992, 1987, 1982) (continued)

Watershed Total Average Potential Potential Potential Potential Potential

River basin code potential potential erosion from erosion from erosion from erosion from erosion from

Watershed name (HUC) erosion erosion croplands forest lands pasture lands rangelands other lands

k tons k tons/mi2

 k tons % k tons % k tons % k tons % k tons %

1982 (continued)

Neosho-Illinois River Basin

(continued)

Elk 11070208 566 0.55 222 39 5 1 330 58 0 0 9 2

Lower Neosho 11070209 873 0.40 510 58 8 1 207 24 132 15 17 2

Illinois 11110103 446 0.27 21 5 9 2 275 62 37 8 104 23

Arkansas River Basin

Dirty-Greenleaf 11110102 882 1.12 342 39 2 0 422 48 116 13 0 0

Robert S. Kerr Reservoir 11110104 755 0.42 317 42 10 1 222 29 110 15 96 13

Poteau 11110105 387 0.20 62 16 10 3 246 63 69 18 0 0

Frog-Mulberry 11110201 383 0.30 150 39 4 1 188 49 7 2 33 9

Dardanelle Reservoir 11110202 638 0.34 134 21 7 1 439 69 0 0 58 9

Conway-Point Remove 11110203 679 0.60 429 63 6 1 244 36 0 0 0 0

Petit Jean 11110204 337 0.31 38 11 5 2 271 80 0 0 23 7

Cadron 11110205 482 0.63 334 69 3 1 141 29 0 0 4 1

Fourche La Fave 11110206 59 0.05 34 57 4 7 21 36 0 0 0 0

Lower Arkansas-Maumelle 11110207 510 0.46 475 93 6 1 9 2 0 0 21 4

Kiamichi-Little River Basin

Kiamichi 11140105 500 0.27 5 1 14 3 344 69 138 28 0 0

Upper Little 11140107 114 0.08 0 0 14 12 93 82 0 0 7 6

Mountain Fork 11140108 83 0.10 0 0 7 8 61 74 0 0 15 18

Lower Little 11140109 150 0.08 38 26 17 11 94 63 0 0 0 0

Ouachita-Saline River Basin

Ouachita Headwaters 08040101 73 0.05 10 13 7 9 56 77 0 0 0 0

Upper Ouachita 08040102 275 0.16 171 62 23 8 81 30 0 0 0 0

Little Missouri 08040103 447 0.21 175 39 20 4 222 50 0 0 31 7

Upper Saline 08040203 2,317 1.36 28 1 18 1 131 6 0 0 2,140 92

Upper White River Basin

Beaver Reservoir 11010001 1,051 0.41 5 0 15 1 911 87 120 11 0 0

James 11010002 1,354 0.94 231 17 4 0 1,076 79 0 0 43 3

Bull Shoals Lake 11010003 1,834 0.71 64 4 14 1 1,353 74 370 20 31 2

Middle White 11010004 577 0.39 167 29 10 2 186 32 113 20 100 17

Buffalo 11010005 775 0.58 5 1 9 1 709 91 0 0 53 7

North Fork White 11010006 978 0.53 134 14 11 1 645 66 169 17 20 2

Little Red 11010014 1,050 0.58 777 74 14 1 237 23 0 0 22 2

Upper Black River Basin

Upper Black 11010007 1,262 0.66 1,171 93 12 1 79 6 0 0 0 0

Current 11010008 1,199 0.46 372 31 19 2 807 67 0 0 0 0

Lower Black 11010009 750 0.96 564 75 3 0 178 24 0 0 5 1

Spring 11010010 424 0.35 13 3 8 2 398 94 0 0 5 1

Eleven Point 11010011 553 0.46 111 20 7 1 421 76 0 0 15 3

Strawberry 11010012 218 0.28 32 15 5 2 168 77 4 2 10 4

HUC = hydrologic unit code; k = thousand; mi2 = square mile.

Source: USDA NRCS (1997).

234
Figure 4.9—Average potential erosion in the aquatic study area by watershed for all land use

categories in 1992 (USDA NRCS 1997).

The Natural Resources Conservation Service defines

“other” lands (table 4.11) as developed land and other

rural land including marshlands, farmsteads, barren land

such as salt flats, and land enrolled in the Conservation

Reserve Program. In more than half of the Assessment

area watersheds, potential erosion rates from other

lands are 2 percent or less TPE. The watersheds with

the highest potential erosion from “other” lands are in

the southeastern, east central, and western portions of

the Assessment area. The Upper Saline (85 percent),

South Grand (38 percent), and Little Red (25 percent)

watersheds had the highest potential erosion rates for

“other” lands in 1992.

Implications and Opportunities

Best management practices and other conservation

measures appear to be working, because total erosion

declined in more than half of the Ozark-Ouachita

Highlands area watersheds for the 3 years studied.

Since pasture lands had the highest potential erosion in

most Assessment area watersheds for 1982, 1987, and

1992, it is apparent that pasture management needs

improvement.

Oklahoma

Arkansas

Missouri

High

Medium

Low

235
Pesticides—Applications and Distributions

Question 4.10: Which pesticides are most

frequently applied in the Assessment area,

and to what extent are they distributed?

Pesticides are chemicals, primarily synthetic organic

compounds, that are not naturally present in water, air,

or soil and are used to control unwanted plants or

animals (Ware 1989). These chemicals may have

effects other than those intended for their use, including

impacts on non-target organisms; accumulation in soil,

water, and organisms; and degradation of water quality.

 Key Findings

Ozark Plateaus

 1. Approximately 4.4 million pounds (lbs) of active

ingredients per year from 130 pesticides were

applied on 25 crop types within the Ozark Plateaus

Province from 1987 through 1991.

 2. The herbicides 2,4-D, atrazine, propanil,

metolachlor, alachlor, trifluralin, dicamba, and

glyphosate were the eight pesticides used most

extensively on or in the Ozark Plateaus.

 3. The most frequently applied pesticide was 2,4-D;

an estimated 750,000 lbs per year of 2,4-D were

applied in the Ozark Plateaus.

Arkansas Valley

 1. Approximately 771,000 lbs of active ingredients per

year from 128 pesticides were applied on 25 crop

types within the Arkansas Valley from 1987 to

1991.

 2. The seven pesticides used most extensively in the

Arkansas Valley were the herbicides 2,4-D,

propanil, trifluralin, atrazine, metolachlor, and

dicamba and the fungicide sulfur.

 3. The most frequently applied pesticide was 2,4-D;

an estimated 108,000 lbs per year of 2,4-D were

applied in the Arkansas Valley.

Ouachita Mountains

 1. Approximately 356,000 lbs of active ingredients per

year from 127 pesticides were applied on 22 crop

types within the Ouachita Mountains from 1987 to

1991.

 2. The herbicides 2,4-D, dicamba, atrazine,

metolachlor, trifluralin, and glyphosate and the

fungicide, sulfur, were the seven pesticides used

most extensively in the Ouachita Mountains.

 3. The most frequently applied pesticide in the

Ouachita Mountains was 2,4-D, with an estimated

application of 65,000 lbs per year.

Data Sources and Methods of Analysis

Data about pesticide applications on croplands are

available for 130 pesticides and 25 crop types from 1987

through 1991 (Gianessi and Puffer 1991, 1992a, 1992b).

In this report, data from crop and pasture applications of

pesticides only are considered because data from other

land uses were not available in computerized data

bases. However, pesticide use in forest areas is minimal

in comparison with its use on crops (Courtenay 1996).

Pesticide use in urban areas is confined to a minor part

of the Assessment area. The Aquatic Team estimated

pesticide use from county-level totals. For counties

located along the boundary of the Highlands or for

counties included more than once because of their

position in multiple physiographic sections within the

Assessment area, the team applied a correction factor

based on the percentage of the county within the

Assessment or physiographic area.

Patterns and Trends

Ozark Plateaus. Approximately 4.4 million lbs of

active ingredients per year from 130 pesticides were

applied on 25 crop types within the Ozark Plateaus from

1987 through 1991 (table 4.12). The herbicides 2,4-D,

atrazine, propanil, metolachlor, alachlor, trifluralin,

dicamba, and glyphosate were the eight pesticides used

most extensively throughout the Ozark Plateaus. Use of

these herbicides accounts for approximately 63 percent

of the total pesticides applied in the Ozark Plateaus.

Pesticide use generally was greatest in areas where the

236
Table 4.12—Estimated annual cropland and pasture applications of selected pesticides in the Assessment

area, pesticide type, and use, 1987 through 1991

Active ingredient

Pesticide applied Type Use

k lb/year

Ozark Plateaus

2,4-D 750 Herbicide Grains, pasture, selected fruits and vegetables

Atrazine 494 Herbicide Corn and sorghum

Propanil 463 Herbicide Rice

Metolachlor 289 Herbicide Vegetables, nuts, and cotton

Alachlor 257 Herbicide Vegetables, cotton, and nuts

Trifluralin 187 Herbicide Grains, vegetables, and nuts

Dicamba 167 Herbicide Corn and forage

Glyphosate 165 Herbicide Rice, cotton, soybeans, and sorghum

Othera 1,628

Total 4,400

Arkansas Valley

2,4-D 108 Herbicide Grains, pasture, selected fruits and vegetables

Sulfur 78 Fungicide Fruits and vegetables

Propanil 66 Herbicide Rice

Trifluralin 54 Herbicide Grains, vegetables, and nuts

Atrazine 46 Herbicide Corn and sorghum

Metolachlor 43 Herbicide Vegetables, nuts, and cotton

Dicamba 40 Herbicide Corn and forage

Otherb 336

Total 771

Ouachita Mountains

2,4-D 65 Herbicide Grains, pasture, selected fruits and vegetables

Sulfur 48 Fungicide Fruits and vegetables

Dicamba 26 Herbicide Corn and forage

Atrazine 26 Herbicide Corn and sorghum

Metolachlor 17 Herbicide Vegetables, nuts, and cotton

Trifluralin 18 Herbicide Grains, vegetables, and nuts

Glyphosate 16 Herbicide Rice, cotton, soybeans, and sorghum

Otherc 211

Total 356

Total applied in the

 Assessment area 5,521

k lb/year = thousand pounds per year.

a Additional 122 pesticides with application rates of less than 150,000 pounds per year of active ingredient.

b Additional 121 pesticides with application rates less than 40,000 pounds per year of active ingredient.

c Additional 120 pesticides with application rates less than 15,000 pounds per year of active ingredient.

Source: Active ingredient applied from Gianessi and Puffer (1991, 1992a, b); description of use modified from Baldwin and

others (1994), Becker and others (1992), Johnson and Jones (1994), Sine (1991), Spradley (1991, 1992).

237
Figure 4.10—Major pesticide use in the Assessment area by county, 1987 through 1991 (calculated from data in Gianessi and Puffer 1991;

1992a, b).

dominant land use was pasture land in the Springfield

and Salem Plateaus and in croplands in the Osage

Plains and Mississippi Alluvial Plain.

The most frequently applied pesticide in the Assessment area was 2,4-D (fig. 4.10). A selective herbicide,

2,4-D was most often applied to control broadleaf

weeds in pastures and cropland. Within the Ozark

Plateaus, 2,4-D was applied most heavily in areas

where pasture was the dominant crop type (in the

Springfield and Salem Plateaus). An estimated 750,000

lbs/year of 2,4-D were applied in the 90 counties of the

Ozark Plateaus. Usage per county within the Ozark

Plateaus ranged from 1 lb/year in several counties in

Arkansas, Missouri, and Oklahoma to 14,000 lbs/year in

Wright County, MO. The median usage in this area was

184 lbs/year.

2,4-D Atrazine Propanil

Metolachlor Alachlor Trifluralin

Study unit boundary

1,000–10,000

Greater than 10,000

Less than 10

10–100

100–1,000

State boundary

Pesticide use, in pounds per year

238
Atrazine, propanil, metolachlor, alachlor, trifluralin,

dicamba, and glyphosate were the other most frequently

used pesticides in the Ozark Plateaus. All of these

pesticides are herbicides used to control various weeds

and grasses, primarily in cropland areas. Use of these

pesticides within counties of the Ozark Plateaus ranges

from 1 to about 141,000 lbs/year, with median per

county application ranging from about 15 to 37,000 lbs/

year.

Arkansas Valley. Approximately 771,000 lbs/year of

active ingredients from 128 pesticides were applied on

25 crop types within the Arkansas Valley from 1987

through 1991. The herbicides 2,4-D, propanil, trifluralin,

atrazine, metolachlor, and dicamba, and the fungicide,

sulfur, were the seven pesticides used most extensively

in the Arkansas Valley, accounting for approximately 56

percent of the total pesticides applied (table 4.12).

The most frequently applied pesticide in the Arkansas Valley was 2,4-D (table 4.12, fig. 4.10), applied

mainly to control broadleaf weeds in pasture and

cropland. An estimated 108,000 lbs/year of 2,4-D were

applied in the 32 counties in the Arkansas Valley. Usage

ranged from 1 lb/year in several counties in Arkansas

and Oklahoma to 6,000 lbs/year in Muskogee County,

OK. The median usage in the Assessment area was

144 lbs/year.

Sulfur, propanil, trifluralin, atrazine, metolachlor, and

dicamba were the other most frequently used pesticides

in the Arkansas Valley. With the exception of sulfur—a

fungicide used on fruits and vegetables—these pesticides are herbicides used to control various weeds and

grasses primarily in cropland areas. Use of each of

these pesticides ranged from 1 to about 34,000 lbs/year

in individual counties, with median county application

rates ranging from about 47 to 4,500 lbs/year.

Ouachita Mountains. Approximately 356,000 lbs of

active ingredients per year from 127 pesticides were

applied on 22 crop types within the Ouachita Mountains

part of the Assessment area from 1987 to 1991. The

herbicides 2,4-D, dicamba, atrazine, metolachlor, trifluralin, and glyphosate and the fungicide sulfur were the

seven pesticides used most extensively throughout the

Ouachita Mountains. Use of these pesticides accounts

for approximately 59 percent of the total pesticides

applied in the Ouachita Mountains (table 4.12).

The most frequently applied pesticide in the Ouachita

Mountains was 2,4-D (table 4.12, fig. 4.10). This

herbicide most often was applied to control broadleaf

weeds in pasture and cropland. An estimated 65,000 lbs/

year of 2,4-D were applied in the 26 counties of the

Ouachita Mountains from 1987 through 1991. Usage

ranged from 1 lb/year in several counties in Arkansas

and Oklahoma to 4,900 lbs/year in McCurtain County,

OK. The median usage in this area was 135 lbs/year.

Sulfur, dicamba, atrazine, metolachlor, trifluralin, and

glyphosate were the other most frequently used pesticides in the Ouachita Mountains (table 4.12, fig. 4.10).

With the exception of sulfur, these pesticides are

herbicides used to control various weeds and grasses

primarily in cropland areas. Use of each of these

pesticides ranges from 1 to about 17,000 lbs/year in

individual counties, with median county application rates

ranging from about 10 to 300 lbs/year.

Pesticides in Surface Water

Question 4.11: What are the current and

potential effects of pesticides on surface water

in the Highlands?

Pesticides in surface water discussed in this report

include a wide variety of classes of herbicides and

insecticides. However, data about pesticides affecting

water quality for the Assessment area are limited. The

Ozark Plateaus NAWQA study recently increased the

amount of available pesticide data for that province

(Bell and others 1996, 1997).

239
 Key Findings

Ozark Plateaus

 1. Pesticide data are available for 1,002 samples from

141 surface water sampling sites in the Ozark

Plateaus.

 2. Many sites were sampled only once (42 sites) or

twice (19 sites) during the 1970 through 1990

period of record.

 3. About 50 percent of the 1,002 samples were

collected in the mid-1970’s and early 1980’s.

 4. Thirty-four of the 50 pesticides were below the

detection limit for all the samples collected; 16

pesticides were detected in 132 samples collected

from 43 sites.

 5. The pesticide detected most often was the insecticide toxaphene, detected in 17 of 866 samples from

5 of 112 sites. The concentration of toxaphene in

samples with detections ranged from 0.1 to 6.0

milligrams per liter (mg/L).

Arkansas Valley

 1. Pesticide data are available for 53 samples from 14

sites in the Arkansas Valley.

 2. Many sites were sampled only once (four sites) or

twice (seven sites) during the 1975 through 1995

period of record.

 3. About 65 percent of the 53 samples were collected

in the early and mid-1980’s.

 4. Three of the nine pesticides were below the

detection limit for all the samples collected; six

pesticides were detected in three samples collected

from three sites.

 5. Five pesticides (DDE, DDT, aldrin, dieldrin, and

lindane) were detected in 3 of 53 samples from 3

of 14 sites. The maximum concentration for these

pesticides was 0.001 mg/L, except for DDT (0.002

mg/L).

Ouachita Mountains

 1. Pesticide data are available for 245 samples from

19 sites in the Ouachita Mountains.

 2. About 64 percent of the 245 samples were collected in the late 1970’s and early 1980’s.

 3. Sixteen of 23 pesticides were below the detection

limit for all the samples collected; 7 pesticides were

detected in 13 samples collected from 10 sites.

 4. The most commonly detected pesticide is methyl

parathion, found in 10 of 234 samples at 10 of 20

sites, with concentrations ranging from 0.001 to

0.002 mg/L.

Data Sources and Methods of Analysis

Pesticide concentration data (here the term “pesticide” is used to refer to both pesticides and pesticide

metabolites, the latter being a product of the chemical

breakdown of pesticides in the environment) and other

water quality data are collected by many Federal, State,

and local governmental agencies for a variety of

purposes. Numerous sources of pesticide data were

available for the Assessment area, but the Aquatic

Team used data collected by Federal or State governmental agencies and stored in computerized data bases

only (table 4.13). Three Federal and three State agencies collected and maintained records of pesticide data

for the majority of the surface water sampling sites in

the Assessment area during the period of record (water

years 1970 through 1990 for the Ozark Plateaus and

1975 through 1995 for the Arkansas Valley and

Ouachita Mountains). Each agency has different

objectives for collecting pesticide data; these objectives

affect the spatial, temporal, and hydrologic distributions

of the data. No long-term pesticide monitoring networks

were in operation in the Assessment area during the

period of record.

Most of the available computerized pesticide data

resides in two national data bases: (1) the Geological

Survey’s national Water Data Storage and Retrieval

System (WATSTORE), and (2) The EPA’s STORET.

The initial retrieval from WATSTORE and STORET

located about 80,000 samples from 2,300 sample sites in

the Assessment area for the water years 1970 through

1990 (Ozark Plateaus) and 1975 through 1995

(Ouachita Province). The Aquatic Team searched these

80,000 samples for pesticide data, using more than 700

pesticide names, and then applied several additional

screening techniques: (1) for cases in which more than

one agency collected samples at sites that were in close

proximity to each other, the team combined these sites

to represent a single site; (2) for cases in which more

240
than one sample was collected at a particular site on a

single day, the team used data from the first sample of

the day only to avoid creating bias in the statistical

analysis; and (3) the team excluded from the final data

set any pesticides represented by fewer than five

samples. The final data set for this report contains 1,300

samples from 173 sites. All of the surface water

pesticide data for the Ozark Plateaus described in this

report is from the Ozark Plateaus NAWQA study

contained in Bell and others (1996). Table 4.14 summarizes the number of pesticide sampling sites and samples

collected for the Assessment area by agency.

Patterns and Trends

Spatial and temporal distributions of pesticide

data. The spatial and temporal distributions (sampling

places and time periods) of pesticide data are important

factors in evaluating the significance of that data. When

assessing how representative and suitable data are for

statistical analysis, important factors are site and basin

characteristics, land use, and spatial and temporal

distributions.

Spatial distribution of the surface water sampling

sites is not uniform. Pesticide data are available for

Table 4.13—Major sources of pesticide data for the aquatic study area

Agency Data collection purpose, type, and accessibility

Federal agencies

U.S. Army Corps of Engineers Resource assessment on Corps-developed projects; variety of water-quality

data, sometimes collected in cooperation with other Federal agencies; data

available from STORET and WATSTORE.

U.S. Environmental Protection Agency Regulatory. Wide variety of water-quality data, sometimes collected in cooperation with State agencies; all data in STORET; information on well construction

and streamflow available.

U.S. Geological Survey Water resources assessment and research; limited monitoring network for

ground and surface water quality; all data are computerized in WATSTORE

including some State agency data; information on streamflow and well construction available.

State agencies

Arkansas Dept. of Pollution Control Regulatory monitoring of 110 surface water sites statewide, 46 sites within the

and Ecology Assessment area; samples analyzed for inorganic constituents, with some

pesticide data and fish-tissue analysis for metals and organics; data are

computerized in WATSTORE and STORET; information available on

streamflow.

Kansas Dept. of Health and Environment Monitoring network of surface and ground water quality originally in cooperation with the U.S. Geological Survey, but independently since 1990; 20 years of

records, virtually all data in STORET; chemical and biological analyses for

approximately 240 surface water sites statewide, 15 sites within the aquatic

study area, of which 30 to 40 percent have streamflow data.

Oklahoma Dept. of Environmental Quality Monitoring ambient water quality and assessment of hazardous waste sites;

most data in STORET or other computerized data base; some fish tissue and

bed sediment data available, some pesticide data available; some streamflow

information available.

241
Table 4.14—Numbers of pesticide sampling sites and samples collected in physiographic areas of the Ozark-Ouachita Highlands,

by monitoring agency

 Ozark Plateaus Arkansas Valley Ouachita Mountains

Agency Sites Samples Sites Samples Sites Samples

U.S. Army Corps of Engineers 1 2 0 0 0 0

U.S. Environmental Protection Agency 39 70 0 0 0 0

U.S. Geological Survey 30 158 1 2 1 7

AR Dept. of Pollution Control and Ecology 46 582 13 51 18 238

KS Dept. of Health and Environment 17 168 0 0 0 0

OK Dept. of Environmental Quality 8 22 0 0 0 0

Total 141a 1,002 14 53 19 245

a The Illinois River near Tahlequah, OK, was sampled by the U.S. Geological Survey and Oklahoma Department of Environmental Quality (and therefore

was counted twice here).

1,002 samples from 141 surface water sites in the

Ozark Plateaus, for 53 samples from 14 sites in the

Arkansas Valley, and for 245 samples from 19 sites in

the Ouachita Mountains (fig. 4.11 and table 4.15). The

density of sampling sites is greatest in the Springfield

Plateau and Osage Plains and least for the St. Francois

Mountains and western part of the Salem Plateau,

Arkansas Valley, and Ouachita Mountains. In the Ozark

Plateaus, most surface water sampling sites have

drainage basins in the Springfield (45 sites) and Salem

(43 sites) Plateaus; fewer have drainage basins in the

Osage Plains (18 sites) and Boston Mountains (3 sites).

Thirty-one surface water sites have drainage basins that

cover parts of two or more physiographic areas within

the Assessment’s borders. All or part of the drainage

basins for 8 of the 11 sites where 20 or more samples

were collected are located in the Springfield Plateau.

In general, sites were sampled infrequently in the

mid-1970’s and early 1980’s. In the Ozark Plateaus,

many sites were sampled only once (42 sites) or twice

(19 sites) during the water years 1970 through 1990.

The sites with the most samples collected are the White

River near Norfork, AR (site 33, 39 samples), and the

Neosho River at Chetopa, KS (site 82, 33 samples).

About 50 percent of the 1,002 samples were collected in

the mid-1970’s and early 1980’s. The 5 years in which

the largest number of samples were collected are 1982

(124 samples), 1981 (117 samples), 1974 (97 samples),

1975 (83 samples), and 1973 (82 samples). Samples

were collected in 16 or more years at the Spring River

near Waco, MO (site 106, 17 years), and the Neosho

River at Chetopa, KS (site 82, 16 years). The White

River near Norfork, AR (site 33), had the most consecutive years (water years 1981 to 1987) in which

three or more samples were collected.

In the Arkansas Valley, many sites were sampled

only once (four sites) or twice (seven sites) during the

water years 1975 through 1995. The sites with the most

samples collected are the Petit Jean River near

Booneville, AR (site 147, 18 samples), and the Fourche

La Fave River near Gravelly, AR (site 151, 11 samples).

About 65 percent of the 53 samples were collected in

the early and mid-1980’s. The 2 years in which the

largest number of samples were collected are 1984 (14

samples) and 1985 (8 samples). The Petit Jean River

near Booneville, AR (site 147), had the most consecutive years (water years 1976 through 1982) in which at

least one sample was collected.

In the Ouachita Mountains, most sites were sampled

more than twice during the water years 1975 to 1995.

The sites with the most samples collected are the Little

River near Horatio, AR (site 165, 34 samples), and

Cossatot River near Lockesburg, AR (site 167, 31

samples), both just south of the Ouachita Mountains.

About 64 percent of the 245 samples were collected in

the late-1970’s and early 1980’s. The 2 years in which

the largest number of samples were collected are 1982

(36 samples) and 1981 (31 samples). The Cossatot

River near Lockesburg, AR (site 167), had the most

consecutive years (water years 1975 through 1982) in

which at least one sample was collected.

Assessment of conditions at surface water sites.

Water quality is affected by factors related to physiography, geology, land use, and other human activities.

242
Figure 4.11—Locations of surface water pesticide sampling sites and sites where pesticides were detected in the

Assessment area (Bell and others 1996).

141

142

143

144

145

146

147 148

149

150

151 152

153

154

155

156

157 159 160

161

165 167 169

173

158 162

164

166

168

170

171

172

44

26

35

6

1

61

48

30

27 24

9

21

7

68 67

50 36

37 31

18 25

15 13

57 58

20

64

65

59

54

52

23

60

11 10

8

43 32

38

39

40

41

55 46

33

17

29

12

22

62

63

66 69

53 49

34 42

51 47

56

45 28

19 16 14

4

5 3

2

120

111

113

110

107

100 98

70

121

74 72

78

75

76

77

79

89

97

86

109

108

115

116

118

114

112

119

117

123

124

125

122

135 132

130 133

128

127

126

129

131 134

136

137 138

139

140

104 105

96

84

85

82

71

101

103

93

87

73

106

102

94

95 92 90

88

91

83

80

81

99

Kansas

Oklahoma

Missouri

Arkansas

169

163 Surface water pesticide sampling site—number

 refers to site number in table 4.15

Surface water pesticide sampling site where

 at least one pesticide was detected—number

 refers to site number in table 4.15

Ozark Plateaus

Province

Ouachita

Province

243
Site

number in

fig. 4.11 Site name

1 Illinois River at Highway 64 Bridge, OK

2 White River at Oil Trough, AR

3 White River near Salado, AR

4 White River at Batesville, AR

5 White River above Batesville, AR

6 Grand Neosho River near Fort Gibson Dam, OK

7 Baron Fork at Dutch Mills, AR

8 Bear Creek west of Marshall, AR

9 Illinois River near Tahlequah, OK

10 Buffalo River near St. Joe, AR

11 Buffalo River near Hasty, AR

12 North Sylamore Creek near Fifty Six, AR

13 White River below Fayetteville, AR

14 Strawberry River near Smithville, AR

15 West Fork White River east of Fayetteville, AR

16 Mill Creek near Melbourne, AR

17 Buffalo River near Harriet, AR

18 Illinois River at Savoy, AR

19 Black River at Black Rock, AR

20 White River near Goshen, AR

21 Illinois River south of Siloam Springs, AR

22 White River at Calico Rock, AR

23 Holman Creek near Huntsville, AR

24 Illinois River near Watts, OK

25 Illinois River near Siloam Springs, AR

26 Grand Neosho River above Industrial Park, OK

27 Sager Creek near Siloam Springs, AR

28 Spring River at Imboden, AR

29 North Fork River at Norfork, AR

30 Flint Creek near West Siloam Springs, OK

31 Osage Creek near Elm Springs, AR

32 Crooked Creek at Yellville, AR

33 White River near Norfork, AR

34 Spring River at Ravenden, AR

35 Neosho River at State Highway 33 Bridge, OK

36 Spavinaw Creek north of Sycamore, OK

37 Flint Creek north of Siloam Springs, AR

38 Crooked Creek at Harrison, AR

39 Crooked Creek above Harrison, AR

40 Crooked Creek near Harrison, AR

41 Crooked Creek below Harrison, AR

42 Eleven Point River near Pocahontas, AR

43 Crooked Creek at Pyatt, AR

44 Pryor Creek at Highway 69a Bridge, OK

45 Black River at Pocahontas, AR

46 Hicks Creek near Mountain Home, AR

47 Current River near Pocahontas, AR

48 Spavinaw Creek near Sycamore, OK

49 Spring River near Hardy, AR

50 Spavinaw Creek near Cherokee City, AR

51 Eleven Point River near Ravenden Springs, AR

52 Osage Creek above Berryville, AR

53 South Fork Spring River at Saddle, AR

54 Osage Creek below Berryville, AR

55 White River at Bull Shoals Dam near Flippin, AR

56 Black River near Corning, AR

57 Mckisic Creek tributary near Bentonville, AR

Table 4.15—Surface water sampling sites for which pesticide data are available

 Site name

58 White River at Beaver Dam near Eureka Springs, AR

59 Kings River near Berryville, AR

60 Long Creek near Denver, AR

61 Neosho River near Langley, OK

62 South Fork of Spring River near Moko, AR

63 South Fork of Spring River near Salem, AR

64 White River at Beaver, AR

65 White River near Beaver, AR

66 Spring River near Thayer, MO

67 Little Sugar Creek at Caverna, MO

68 Butler Creek near Sulphur Springs, AR

69 Myatt Creek near Lanton, MO

70 Current River below Hawes Campground, MO

71 Neosho River near Commerce, OK

72 Spring River near Verona, MO

73 Spring River at Devil’s Prominade Bridge, OK

74 Spring River 0.6 mi. upstream from U.S. 60 Bridge, MO

75 Unnamed creek between Syntex and Spring, MO

76 Spring River west of Verona, MO

77 Douger Brook at State Route P Bridge, MO

78 Spring River 2.4 mi. downstream of Douger Bridge, MO

79 James River near Boaz below Wilson Creek, MO

80 Spring River at Baxter Springs, KS

81 Spring River near Baxter Springs, KS

82 Neosho River at Chetopa, KS

83 Shoal Creek near Galena, KS

84 Neosho River near Chetopa, KS

85 Labette Creek near Chetopa, KS

86 James River 2 mi. above Wilson Creek, MO

87 Short Creek near Galena, KS

88 Jones Creek near Fidelity, MO

89 Wilson Creek downstream of South Creek, MOa

90 Center Creek above Fidelity, MO

91 Turkey Creek near Joplin, MO

92 Center Creek near Carterville, MO

93 Shawnee Creek near Crestline, KS

94 Center Creek near Smithfield, MO

95 Center Creek south of Smithfield, MO

96 Neosho River near Oswego, KS

97 Wilson Creek upstream of South Creek, MOb

98 Current River above Powder Mill, MO

99 Spring River near Crestline, KS

100 Jacks Fork above Two Rivers, MO

101 Spring River near Galena, KS

102 Spring River south of Waco, MO

103 Cow Creek near Lawton, KS

104 Labette Creek near Labette, KS

105 Lightning Creek near Oswego, KS

106 Spring River near Waco, MO

107 Current River below Montauk State Park, MO

108 Neosho River water station no. 1, KS

109 Marmaton River near Fort Scott, KS

110 Devil’s Elbow on Big Piney, MO

111 Gasconade at Highway Y, MO

112 Marmaton River near Nevada, MO

113 Gasconade River near Jerome, MO

114 Little Osage River near Horton, MO

Site

number in

fig. 4.11

(continued)

244
Site

number in

fig. 4.11 Site name

115 Little Osage River near Fulton, KS

116 Little Osage River at Fulton, KS

117 Osage River above Schell City, MO

118 Marais des Cygnes drainage ditch, MO

119 Miami Creek near Butler, MO

120 Osage Gasconade, Bagnell Dam, MO

121 Meramec River at Meramec Park, MO

122 Calvey Creek no. 1, MO

123 Tebo Creek, Henry Co. Highway PP, MO

124 Calvey Creek no. 2, MO

125 Calvey Creek no. 3, MO

126 Meramec River at Highway 21 Bridge, MO

127 Romaine Creek near mouth, MO

128 Sugar Creek near mouth, MO

129 Saline Creek before confluence of Sugar Creek, MO

130 Meramec River upstream of I-44 Bridge at Times Beach, MO

131 Meramec River below Fenton and upstream of Marina, MO

132 Meramec River downstream of Glencoe, MO

133 Meramec River upstream of Valley Park Bridge, MO

134 Chrysler car plant-industrial waste, MO

135 Fishpot Creek at Hanna Road Bridge, St. Louis, MO

136 Grand Glaize Creek at Marshall Road Bridge, MO

137 Meramec R. near Kirkwood, MO, wastewater-treatment

intake

138 Grand Glaize Creek at Carmen Road Bridge, MO

139 Sugar Creek near Ozark View Subdivision, St. Louis, MO

140 Grand Glaize Creek Below Sulphur Springs Road, MO

141 Poteau River east of Waldron, AR

142 Poteau River northwest of Waldron, AR

143 James Fork near Hackett, AR

Table 4.15—Surface water sampling sites for which pesticide data are available (continued)

 Site name

144 Mulberry River at I40 near Mulberry, AR

145 Big Piney Creek at highway 164 near Dover, AR

146 Illinois Bayou near Dover, AR

147 Petit Jean River near Booneville, AR

148 Dutch Creek at Shark, AR

149 Chickalah Creek near Chickalah, AR

150 White Oak Creek near Atkins, AR

151 Fourche La Fave River near Gravelly, AR

152 South Fourche La Fave River at Hollis, AR

153 Stone Dam Creek near Conway, AR

154 Maumelle River at Williams Junction, AR

155 Ouachita River near Mount Ida, AR

156 Ouachita River near Malvern, AR

157 Ouachita River near Donaldson, AR

158 South Fork Caddo River at Fancy Hill, AR

159 Caddo River near Amity, AR

160 Little Missouri River near Langley, AR

161 Saline River west of Benton, AR

162 Saline River near Shaw, AR

163 Kiamichi River near Big Cedar, OK

164 Mountain Fork near Hatfield, AR

165 Little River near Horatio, AR

166 Cossatot River near Umpire, AR

167 Cossatot River near Lockesburg, AR

168 Saline River near Burg, AR

169 Saline River near Lockesburg, AR

170 Prairie Creek near Mena, AR

171 Prairie Creek at Murfreesboro, AR

172 Prairie Creek near Murfreesboro, AR

173 Hurricane Creek near Sardis, AR

a Original site name is “Wilson Creek, downstream”; reference to South Creek added for clarification. b Original site name is “Wilson Creek, upstream”; reference to South Creek added for clarification.

Because of the limited spatial distribution of sampling

sites and gaps in the temporal distribution of the

samples, the available pesticide data are insufficient to

provide an analysis of the effects of these factors on

water quality in the Ozark-Ouachita Highlands area.

The following sections provide a descriptive statistical

summary of recent historical pesticide data collected at

surface water sites in the Assessment area.

Descriptive statistics are used to show the central

tendency and variation in the pesticide data. The minimum, maximum, and 50th percentile (median) of samples

with detected concentrations are presented. The median

is used to represent the central tendency of the data

instead of the mean because the median is less sensitive

to extreme values. The median is not reported unless five

or more observations exceeded the detection limit. The

maximum detection limit shows the censored concentration with the highest value for a particular parameter.

The locations of the 56 sites within the Assessment

area where at least 1 pesticide was detected are shown

in figure 4.11. (See table 4.15 for the site names.)

Pesticides were detected in most parts of the Assessment area where sampling sites are located, but primarily in the southern, western, and extreme northeastern

parts of the Ozark Plateaus and in the Arkansas Valley.

A statistical summary of pesticide data collected for 50

pesticides in the Ozark Plateaus, 9 pesticides in the

Arkansas Valley, and for 23 pesticides in the Ouachita

Mountains is shown in table 4.16. In the Ozark Plateaus,

34 of the 50 pesticides were below the detection limit

for all the samples collected; 16 pesticides were

detected in 132 samples collected from 43 sites. In the

Site

number in

fig. 4.11

245
Table 4.16—Statistical summary of detected pesticide concentrations from surface water sampling sites in the Ozark Plateaus

(water years 1970 through 1990), the Arkansas Valley, and Ouachita Mountains (1975 through 1995)

Minimum Median Maximum Sites with a

STORET Pesti- detected detected detected detectable Samples with Max.

parameter cide concen- concen- concen- concen- a detectable detection

codea Parameter name type tration tration tration Samples Sites tration concentration limit

 - - - - - - - - - - - - mg/L - - - - - - - - - - - mg/L

Ozark Plateaus

34541 1,2-dichloropropane, total F 54 26 0 0 10

39730 2,4-D, total H 0.02 0.03 0.61 514 76 9 13 0.8

34601 2,4-dichlorophenol, total G 55 27 0 0 52

39360 DDD, total I 0.01 – 0.01 312 54 1 1 1.0

39365 DDE, total M 0.001 0.001 0.01 718 75 15 16 1.0

39370 DDT, total I 0.001 0.002 0.023 794 88 14 15 10

39305 o,p’-DDT, total I 90 11 0 0 10

39300 p,p’-DDT, total I 169 48 0 0 1.1

39040 DEF, total D 17 2 0 0 0.01

39250 PCN, total I 59 16 0 0 5.0

77825 Alachlor, total recoverable H 0.015 0.66 4.2 115 23 5 6 0.5

39330 Aldrin, total I 0.001 0.001 0.001 977 122 13 14 1.0

39337 Alpha benzene hexachloride, I 0.02 – 0.02 93 44 3 3 0.19

total

39338 Beta benzene hexachloride, I 72 30 0 0 0.38

total

39062 Chlordane, cis isomer, ww, I 10 3 0 0 0.1

total

39350 Chlordane, total I 0.2 0.3 0.5 353 76 3 7 3.8

39065 Chlordane, trans isomer, ww, I 10 3 0 0 0.1

total

39071 Chlordane-nonachlor, trans I 10 3 0 0 0.1

isomer, ww, total

81403 Chloropyrifos, total I 62 28 0 0 10

34704 Cis-1,3-dichloropropene, F 51 23 0 0 1.0

total

34699 Trans-1,3-dichloropropene, F 52 24 0 0 1.0

total

39570 Diazinon, total I 0.01 – 0.01 60 14 1 1 0.1

39380 Dieldrin, total I 0.001 0.001 0.01 990 132 15 15 2.0

39011 Disyston, total I 17 2 0 0 0.01

39388 Endosulfan I, total I 188 50 0 0 1.0

34361 Endosulfan I, ww, recoverable I 70 29 0 0 0.38

34356 Endosulfan beta, total I 70 29 0 0 0.63

34351 Endosulfan sulfate, total I 70 29 0 0 1.3

39398 Ethion, total I 46 10 0 0 0.01

39421 Heptachlor epoxide, dissolved I 7 7 0 0 1.0

39420 Heptachlor epoxide, total I 438 97 0 0 1.0

39410 Heptachlor, total I 0.014 – 0.23 439 97 1 3 1.0

39700 Hexachlorobenzene, total I 71 32 0 0 10

39340 Lindane, total I 0.012 0.052 0.29 194 59 6 12 0.2

39782 Lindane, total I 0.03 – 0.07 810 81 1 3 10

39530 Malathion, total I 235 60 0 0 1.0

39480 Methoxychlor, total I 365 69 0 0 50

39600 Methyl parathion, total I 510 59 0 0 7.0

39356 Metolachlor, ww H 80 17 0 0 0.25

81408 Metribuzin, ww H 0.57 – 0.57 101 17 1 1 0.1

39755 Mirex, total I 60 14 0 0 0.01

39540 Parathion, total I 51 11 0 0 0.01

39034 Perthane, total I 34 10 0 0 0.1

39023 Phorate, total I 17 2 0 0 0.01

39760 Silvex, total H 99 17 0 0 0.01

39055 Simazine, total H 843 100 0 0 0.5

39402 Toxaphene, suspended, total I 20 14 0 0 2.5

39400 Toxaphene, total I 0.1 0.7 6.0 866 112 5 17 7.0

34757 Triazine screen by enzyme H 1.0 4.0 5.0 5 5 5 5 –

ww, recoverable

39786 Trithion, total I 46 10 0 0 0.01

(continued)

246
247

Table 4.16—Statistical summary of detected pesticide concentrations from surface water sampling sites in the Ozark Plateaus

(water years 1970 through 1990), the Arkansas Valley, and Ouachita Mountains (1975 through 1995) (continued)

Minimum Median Maximum Sites with a

STORET Pesti- detected detected detected detectable Samples with Max.

parameter cide concen- concen- concen- concen- a detectable detection

codea Parameter name type tration tration tration Samples Sites tration concentration limit

 - - - - - - - - - - - - mg/L - - - - - - - - - - - mg/L

Arkansas Valley

39730 2,4-D, total H 19 7 – – 0.01

39365 DDE, total I – – 0.001 46 13 3 3 0.002

39370 DDT, total I 0.001 – 0.002 46 15 3 3 0.004

39330 Aldrin, total I – – 0.001 46 13 3 3 0.002

39380 Dieldrin, total I – – 0.001 46 15 3 3 0.002

39782 Lindane, total I – – 0.001 46 16 3 3 0.01

39530 Malathion, total I 12 4 0 0 0.001

39600 Methyl parathion, total I – – 0.001 47 16 2 2 0.01

39400 Toxaphene, total I 51 16 0 0 1

Ouachita Mountains

39730 2,4-D, total H 0.04 – 0.04 125 13 1 1 0.01

39365 DDE, total I – – 0.001 219 17 6 6 1

39370 DDT, total I 0.001 0.002 0.003 221 19 7 7 4

39300 p,p’-DDT, total I 23 3 0 0 0.01

77825 Alachlor, total recoverable H 11 3 0 0 0.01

39330 Aldrin, total I 242 14 0 0 0.03

39337 Alpha benzene hexachloride, I 22 3 0 0 0.01

total

39338 Beta benzene hexachloride, I 22 3 0 0 0.01

total

39350 Chlordane, total I 17 4 0 0 0.1

81403 Chloropyrifos, total I 11 3 0 0 0.01

39570 Diazinon, total I 19 5 0 0 0.1

39380 Dieldrin, total I – – 0.001 231 18 7 7 0.06

34361 Endosulfan I, ww, recoverable I 23 3 0 0 0.01

34356 Endosulfan beta, total I 23 3 0 0 0.01

34351 Endosulfan sulfate, total I 23 3 0 0 0.06

39420 Heptachlor epoxide, total I 29 4 0 0 0.01

39410 Heptachlor, total I 29 4 0 0 0.01

39340 Lindane, total I 29 4 0 0 0.01

39782 Lindane, total I 0.01 0.01 0.01 214 18 5 5 0.01

39530 Malathion, total I 93 14 0 0 0.1

39480 Methoxychlor, total I 15 5 0 0 0.07

39600 Methyl parathion, total I 0.001 0.001 0.002 234 20 10 10 0.1

39400 Toxaphene, total I 0.1 0.35 0.7 244 18 3 6 1

mg/L = milligrams per liter; ww = whole water; – = unknown; F = soil fumigant; H = herbicide; G = germicide; I = insecticide; M = metabolite; D = defoliant. a EPA’s Storage and Retrieval code assigned to a parameter based on factors including the medium type and the analytical method used for the analysis.

Arkansas Valley, three of the nine pesticides were

below the detection limit for all the samples collected;

six pesticides were detected in three samples collected

from three sites. In the Ouachita Mountains, 16 of 23

pesticides were below the detection limit for all the

samples collected; 7 pesticides were detected in 13

samples collected from 10 sites.

In the Ozark Plateaus, the insecticide toxaphene

(detected in 17 of 866 samples from 5 of 112 sites) was

the pesticide with the most number of detections. The

concentration of toxaphene in samples with detections

ranged from 0.1 to 6.0 milligrams per liter (mg/L). The

toxaphene sample having the maximum concentration

was collected at the White River near Norfork, AR (site

33), in 1982. Site 33 had 12 toxaphene detections

between 1981 and 1985. Other sites that had toxaphene

samples above the detection limit include: Strawberry

River near Smithville, AR (site 14; 2 samples, 1975,

1982); Spavinaw Creek north of Sycamore, OK (site

36; 1 sample, 1975); Spavinaw Creek near Sycamore,

OK (site 48; 1 sample, 1975); and South Fork Spring

River at Saddle, AR (site 53; 1 sample, 1985).
Table 4.17—Comparison of maximum detected pesticide concentrations in surface

water samples by physiographic area, with selected quality criteria and standards

Maximum concentrationa Drinking

water

Ozark Arkansas Ouachita standard

Pesticide Plateaus Valley Mountains AALCb MCLb

 - - - - - - - - - - - - - - - - - - - - - - - mg/L- - - - - - - - - - - - - - - - - - - - - - - -

Alachlor 4.2 — nd nsg 2.0

Chlordane 0.5 — nd 2.4 2.0

DDT total 0.023 0.002 0.003 1.1 nsg

Dieldrin 0.01 0.001 0.001 2.5 nsg

Heptachlor 0.23 — nd 0.52 0.4

Toxaphene 6.0 nd 0.7 nsg 3.0

AALC = acute aquatic life criteria; MCL = maximum contaminant level; mg/L = milligrams per liter;

— = no samples analyzed; nd = not detected; nsg = no standard or guideline established. a Maximum concentration of samples given in this report.

b Criteria and standards established by the U.S. EPA (AALC, MCL) listed in Nowell and Resek (1994).

Six other pesticides were detected in 12 or more

samples: DDE was detected in 16 of 718 samples from

15 of 75 sites; dieldrin was detected in 15 of 990

samples from 15 of 132 sites; DDT was detected in 15

of 794 samples from 14 of 88 sites; aldrin was detected

in 14 of 977 samples from 13 of 122 sites; 2,4-D was

detected in 13 of 514 samples from 9 of 76 sites; lindane

(parameter code 39340) was detected in 12 of 194

samples from 6 of 59 sites. The maximum concentration

for these six pesticides was less than 1.0 mg/L. The

samples with the maximum concentration of these six

pesticides were collected prior to 1983, with the exception of DDE, which was collected in 1990 at the Illinois

River near Tahlequah, OK (site 9).

In the Arkansas Valley, five pesticides (DDE, DDT,

aldrin, dieldrin, and lindane) were detected in 3 of 53

samples from 3 of 14 sites. The maximum concentration

for these pesticides was 0.001 mg/L, except for DDT

(0.002 mg/L). The three samples were collected at

James Fork near Hackett, AR (site 143), Petit Jean River

near Booneville, AR (site 147), and Fourche La Fave

River near Gravelly, AR (site 151), in the mid-1970’s.

In the Ouachita Mountains, methyl parathion had the

most detections; it was found in 10 of 234 samples at 10

of 20 sites with concentrations ranging from 0.001 to

0.002 mg/L. The two methyl parathion samples having

the maximum concentration were collected at the

Hurricane Creek near Sardis, AR (site 173), in 1976 and

the Ouachita River near Malvern, AR (site 156), in 1976.

For the Assessment area, the highest percentage of

samples with concentrations above the detection limit

were those analyzed for triazine herbicides and metabolites using an enzyme screening technique. All five

samples collected in the northwestern part of the

Assessment area in 1990 had concentrations above the

detection limit. These concentrations ranged from 1.0

mg/L at the Marmaton River near Nevada, MO (site

112), to 5.0 mg/L at the Marais des Cygnes, MO (site

118). Of the other 15 pesticides that had 5 or more

detectable concentrations, only lindane (6.2 percent) and

alachlor (5.2 percent) had detections in more than 4

percent of the samples.

Comparison of pesticide data with selected

quality criteria and standards. The EPA has established quality criteria (suggested but nonenforceable

values) or standards (legally enforceable values) for six

pesticides detected in surface water at sites in the

Assessment area. The maximum concentrations of

these pesticides in surface water samples summarized

in this report are compared with selected quality criteria

and standards and are shown in table 4.17.

The acute aquatic life criterion or criteria (AALC)

established by the EPA (Nowell and Resek 1994)

provide a basis of comparison with the maximum

248
concentration of each of the detected pesticides having

an AALC value. The AALC is a national numerical

criterion designed to prevent unacceptable short-term

effects on a variety of species of fish, benthic invertebrates, and zooplankton. None of the four detected

pesticides that have an AALC value (chlordane, DDT,

dieldrin, or heptachlor) exceeded that value.

The maximum contaminant level (MCL) established

by the EPA (Nowell and Resek 1994) provides a basis of

comparison with the maximum concentration of each of

the detected pesticides having an MCL value (the level to

which a contaminant must be removed to meet Safe

Drinking Act requirements). Because the MCL applies to

treated drinking water, the comparison of concentrations

of detected pesticides in this report with the MCL is

merely for informational purposes.

The comparison of detected pesticides with selected

quality criteria and standards suggests that pesticides do

not pose any widespread or persistent problems in the

Assessment area. However, a complete evaluation was

not possible because of the limited spatial and temporal

distributions of samples, limited number of criteria and

MCL’s, and the synergistic effects of multiple pesticides. The AALC were not exceeded by any samples,

and the MCL was exceeded at two sites, one just

outside the Assessment area, the other near Norfolk,

AR.

Pesticides in Ground Water

Question 4.12: What are the current and

potential effects of pesticides on ground water

in the Highlands?

Pesticides in ground water considered in this report

include a wide range of classes of herbicides and

insecticides. Recent activities and completion of the

Ozark Plateaus NAWQA study have provided abundant

data about pesticides in the ground water of the Ozark

Plateaus. However, there is a shortage of information

for general, non-site-specific pesticide data in the

ground waters of the Ouachita Province.

 Key Findings

Ozark Plateaus Province

 1. Pesticides were detected in 80 of 229 samples of

ground water from 73 of 215 sites.

 2. Twenty pesticides were detected; a maximum of

five pesticides was detected in any one sample.

 3. The most commonly detected pesticides are

tebuthiuron, atrazine, prometon, desethylatrazine,

and simazine. Maximum concentrations range from

0.003 to 1.0 mg/L.

 4. The occurrence and distribution of pesticides are

related to land use. Samples with detectable

pesticides come from sites having a higher percent

of land used for agriculture than samples from sites

with no pesticides detected.

 5. Pesticides are detected more often in samples from

springs than in samples from wells.

Ouachita Province

 1. For the Ouachita Province, very little data are

available from monitoring pesticides in ground

water.

 2. Commonly applied pesticides in forest land—2,4-D,

dichlorprop, hexazinone, and picloram were not

found at any of the eight Ouachita Mountains sites

sampled in 1986.

Data Sources and Methods of Analysis

Several studies have investigated the pesticide

ground water quality in areas in or adjacent to the Ozark

Plateaus. Ground water samples were collected from

near surface aquifers in all or parts of 12 States (Illinois,

Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri,

Nebraska, North Dakota, Ohio, South Dakota, and

Wisconsin) and analyzed for selected herbicides (Kolpin

and others 1994). Ground water samples were collected

in 1990 and 1991 from four counties in west central

Missouri and analyzed for selected herbicides (Ziegler

and others 1994), although little of these data are from

within the Assessment area. Pesticide data were

available for 103 samples collected from 1970 through

1990 from 92 ground water sites within the Ozark

249
Plateaus NAWQA study (Bell and others 1996). Most

of these data were from Ziegler and others (1994) with

only seven sites sampled in the Springfield Plateau and

Ozark aquifers.

Pesticide data and interpretations presented in this

report for the Ozark Plateaus are derived from the

Ozark Plateaus NAWQA study (Adamski 1997).

Ground water samples from 215 wells and springs in the

Springfield Plateau and Ozark aquifers were collected

between 1993 and 1995 and analyzed for 88 pesticides

and metabolites.

Very little ambient ground water monitoring data are

available for pesticides in the Ouachita Province.

Cavalier and Lavy (1987) analyzed for pesticides at

eight sites in the Ouachita Mountains during two

sampling events in May and August of 1987. The sites

sampled comprised five wells and two springs at seven

national forest recreation areas and one well located

near a small community. These ground water samples

were analyzed for four of the herbicides most commonly applied in forest settings—2,4-D, dichlorprop,

hexazinone, and picloram.

Patterns and Trends

Pesticides were detected in about one-third of the

samples collected in the Ozark Plateaus (Adamski

1997a). Pesticides were detected in 80 of 229 ground

water samples (35 percent) from 73 of the 215 sites

(fig. 4.12). Pesticides were detected in samples from 43

springs and 30 wells.

Twenty pesticides were detected in the Ozark

Plateaus (table 4.18) with a maximum of five pesticides

detected in any one sample. The most commonly

detected pesticides were tebuthiuron (31 detections),

atrazine (30), prometon (25), desethylatrazine, a

metabolite of atrazine (19), and simazine (18). These

compounds are herbicides that are commonly used on

Table 4.18—Pesticides detected in ground water and their range of concentrations

in the Ozark Plateaus

Range of

Pesticide Detections concentrations Use

From

Total estimatesa mg/L

Atrazine 30 6 0.001– 1.0 Herbicide

Benfluralin 1 0.003 Herbicide

Carbaryl 4 4 0.012– 0.03 Insecticide

Carbofuran 2 2 0.007– 0.016 Insecticide

Chlorpyrifos 2 1 0.003– 0.013 Insecticide

DCPA 3 0.002– 0.014 Herbicide

Desethylatrazine 19 19 0.002– 0.35 None (metabolite)

Dieldrin 2 0.025– 0.057 Insecticide (banned)

Diuron 2 2 0.01 – 0.18 Herbicide

Lindane 2 0.028– 0.032 Insecticide

Linuron 1 0.016 Herbicide

Metolachlor 5 0.002– 0.003 Herbicide

Metribuzin 3 1 0.004– 0.14 Herbicide

p,p’–DDE 10 10 0.001– 0.003 None (metabolite)

Prometon 25 15 0.002– 0.88 Herbicide

Propanil 2 0.007– 0.012 Herbicide

Propargite 1 0.008 Acaricide

Simazine 18 13 0.001– 0.026 Herbicide

Tebuthiuron 31 9 0.005– 0.24 Herbicide

Trifluralin 1 0.003 Herbicide

mg/L = milligrams per liter.

a Detections for which the reported concentration was an estimated value.

250
Figure 4.12—Locations of ground water pesticide sampling sites and sites where pesticides were

detected in the Ozark Plateaus Province (Adamski 1997a).

Springs Domestic wells Monitoring wells

Missouri

Arkansas

Kansas

Oklahoma

Springs Domestic wells

Kansas

Oklahoma

Missouri

Arkansas North

Flint

Cr.

East

Flint

Cr.

Big Spring

Monitoring wells

Sites sampled with pesticides detected 

Salem Plateau

Springfield Plateau

Inset A

Inset A Inset B

Inset B

Sites sampled with no pesticides detected 

251
pastures and non-crop areas. Atrazine is commonly used

to control weeds in cornfields (Thomson 1989). All other

pesticides were detected in 10 or fewer samples. Sixtyeight other pesticides were not detected in any samples.

For example, Alachlor and 2,4-D, two of the most

commonly used pesticides in the Ozark Plateaus (Bell

and others 1996), were not detected in any samples.

Maximum pesticide concentrations ranged from

0.003 (benfluralin, metolachlor, p,p’-DDE, and trifluralin)

to 1.0 mg/L (atrazine). No pesticide exceeded MCL’s or

health advisory levels for drinking water set by the EPA

(Nowell and Resek 1994).

The occurrence of pesticides in ground water of the

Springfield Plateau and Ozark aquifers confirms the

vulnerability of these aquifers to surface contamination.

Analysis indicates pesticides were detected statistically

more often in samples collected from the Springfield

Plateau aquifer than in samples from the Ozark aquifer.

Pesticides were detected in 18 of 36 samples (50

percent) from the Springfield Plateau aquifer and in 14

of 63 samples (22 percent) from the Ozark aquifer

collected during the survey of 1993 from the Ozark

Plateaus NAWQA study (Adamski 1997a). The relation

between pesticide occurrence and aquifer probably

results from greater percent agricultural land use around

sites in the Springfield Plateau aquifer compared to sites

in the Ozark aquifer.

Pesticide detections were related to land use in

Ozark Plateaus samples with tritium activities greater

than 2.5 picocuries per liter (pCi/L). Tritium activities

greater than about 2.5 pCi/L in ground water indicate

that some portion of the water was recharged to the

ground water system within the past 40 years (Plummer

and others 1993); therefore, the water could be affected

by relatively recent land uses.

Statistically, there were more land uses for agriculture around sites with samples that had detectable

pesticide concentrations than around sites with samples

that had no detectable pesticides within the Ozark

Plateaus. Conversely, percent forest cover was statistically less for sites with samples that had detectable

pesticide concentrations than for sites with samples that

had no detectable pesticides.

Pesticides were detected statistically more often in

samples from springs than in samples from domestic

wells in the Ozark Plateaus. Pesticides were detected in

samples collected from about 47 percent of the springs

and about 22 percent of the wells.

Pesticide detections were related to nitrite plus

nitrate and phosphorus concentrations in samples from

sites in agricultural areas (greater than 80 percent

agricultural land use) of the Springfield Plateau aquifer.

Median nitrite plus nitrate and phosphorus concentrations were statistically greater in samples with detectable pesticide concentrations (median nitrite plus nitrate

= 3.0 mg/L as nitrogen; median phosphorus = 0.02 mg/

L) than in samples with no pesticides detected (median

nitrite plus nitrate = 1.6 mg/L as nitrogen; median

phosphorus < 0.01 mg/L). These results suggest that the

hydrogeologic conditions and land uses that allow

elevated concentrations of nitrite plus nitrate and

phosphorus in ground water also allow pesticides to

occur in ground water.

The pesticides p,p’-DDE and dieldrin were detected

in 10 and 2 samples, respectively, in the Ozark Plateaus.

The EPA banned DDT in 1973 and dieldrin in 1984

(Ware 1989). The occurrence of p,p’-DDE, a metabolite of DDT, and dieldrin in ground water samples

indicates the great stability and persistence of these

compounds in the environment.

In the Ouachita Province, the pesticides 2,4,-D,

dichlorprop, hexazinone, and picloram were not detected

at eight sites distributed across the central area of the

Ouachita Mountains (Cavalier and Lavy 1987). Five

wells and two springs at seven national forest recreation

areas and one well located near a small community

were sampled twice during 1986. These sites represented land uses that were predominantly “forested.”

The pesticides analyzed were chosen as representative

because of the frequency of their use in the area and

for transport and persistence characteristics favoring

potential introduction into the ground water system. The

springs sampled had a relatively low discharge (less

than 1 cubic foot per second) and, as such, are possibly

indicative of short flowpath conditions within smaller

basins. The wells sampled were relatively shallow (less

than 200 ft) and representative of shallow to intermediate aquifer depths.

The limited pesticide data available in the Ouachita

Province make broad interpretation difficult. However,

the pesticides analyzed do not appear to be problematic

with respect to ground water in the central area of the

Ouachita Mountains.

252
Implications and Opportunities

The presence of pesticides in ground water of the

Ozark Plateaus, which was somewhat unexpected

because of the relatively low pesticide use in most of

the province, indicates that water in both the Springfield

Plateau and Ozark aquifers is susceptible to surface

contamination. Like nutrient concentrations, pesticide

detections in the Ozark Plateau aquifers were related to

land use. Increased pesticide applications could easily

result in higher concentrations for ground water in the

Ozark Plateaus.

Pesticide data in ground water are limited for the

Ouachita Province. Only four pesticides were analyzed

at eight sites distributed across the central part of the

Ouachita Mountains. None of these pesticides were

detected, but certainly more data are needed to completely assess the Ouachita Province aquifers.

Animal Wastes

Question 4.13: What are the current status and

potential effects of animal confinement and

waste on aquatic resources in the Assessment

area?

Livestock and poultry wastes are a major source of

nutrient loading in parts of the Assessment area. The

nutrient composition of animal wastes varies widely with

respect to animal species, feed consumption and

content, and age (Fulhage 1989). Animal wastes contain

three major nutrients (nitrogen, phosphorus, and potassium) essential for plant production and are, therefore,

used as a fertilizer for pasture lands. The quantity of

nutrients ultimately available for use by plants from

livestock and poultry wastes varies substantially from

the amount initially excreted. The types of animal

production housing and waste handling systems used

plus different storage times greatly affect the nitrogen

and phosphorus content of animal wastes. The longer

animal wastes remain in the soil before plant uptake, the

more nutrients can be lost through mineralization,

volatilization, denitrification, leaching, and erosion.

Fulhage (1989) indicates that more than one-half of

the nitrogen content of manure will be either used by

plants or volatilized to the atmosphere. Phosphorus in

manure is found in the organic form but is not readily

available to plants until it is broken down by bacteria (a

slow process). Also, phosphorus tends to remain

attached to soil that can erode into receiving waters and

cause excessive plant and algae growth (Fulhage 1989).

 Key Findings

 1. An estimated 358,300 tons (7 tons per square mile

(tons/mi2

)) of nitrogen and 123,400 tons (3 tons/

mi2

) of phosphorus were available from animal

wastes in the Ozark Plateaus in 1992.

 2. An estimated 82,312 tons (6 tons/mi2

) of nitrogen

and 29,460 tons (2 tons/mi2

) of phosphorus were

available from animal wastes in the Arkansas

Valley in 1992.

 3. An estimated 57,555 tons (4 tons/mi2

) of nitrogen

and 20,207 tons (2 tons/mi2

) of phosphorus were

available from animal wastes in the Ouachita

Mountains in 1992.

Data Sources and Methods of Analysis

The Aquatic Team obtained the data used in the

discussion of animal waste nutrient contributions from

two sources: (1) Davis and others (1995) for the Ozark

Plateaus and (2) Puckett (1997) for the Arkansas Valley

and Ouachita Mountains. To facilitate the comparison of

estimates between the two sources of data, the Aquatic

Team developed a correction factor that relates the

values of animal populations and nutrient contributions to

the Ozark Plateaus provided by Davis and others (1995)

with the values provided by Puckett (1997). The team

then applied the correction factor to animal population

and animal waste contribution estimates for the Arkansas Valley and Ouachita Mountains provided by Puckett

(1997).

Patterns and Trends

Amounts of nitrogen and phosphorus available from

the animal wastes produced by livestock and poultry

within the Assessment area in 1992 are shown in table

4.19. An estimated 498,166 tons (7 tons/mi2

) of

nitrogen and 173,067 tons (2 tons/mi2

) of phosphorus

253
Table 4.19—Estimated animal populations and nutrient contributions from

animal wastes by physiographic area in 1992

Animal

Animal population Nitrogen Phosphorus

 - - - - - - - - - -Tons - - - - - - - - - -

Ozark Plateausa

Beef cattle 4,264,000 264,000 85,300

Dairy cattle 231,000 17,300 3,100

Swine 1,087,000 22,400 7,500

Chickensc 498,325,000 29,200 12,400

Turkeysc 25,178,000 25,000 15,100

Total 358,300 123,400

Arkansas Valleyb

Beef cattle 838,763 52,000 16,768

Dairy cattle 26,884 2,013 360

Swine 304,627 6,278 2,102

Chickensc 272,612,423 16,441 6,866

Turkeysc 5,617,476 5,580 3,365

Total 82,312 29,460

Ouachita Mountainsb

Beef cattle 553,816 34,448 11,187

Dairy cattle 4,412 331 60

Swine 362,836 7,477 2,503

Chickensc 258,658,370 15,299 6,457

Turkeysc 496 0 0

Total 57,555 20,207

Total, Assessment area 498,167 173,067

a Davis and others (1995).

b Puckett (1997).

c Chicken and turkey populations are totals produced during a year; nutrient contributions

adjusted based on the average number of chickens and turkeys produced on a single day.

Multiple flocks of chickens (6) and turkeys (2.25) are produced each year.

were available from animal waste. The Ozark

Plateaus Province—with an estimated 358,300 tons (7

tons/mi2

) of nitrogen and 123,400 tons (3 tons/mi2) of

phosphorus—had the largest nutrient contributions

from animal wastes for that year. The Arkansas Valley

had an estimated 82,312 tons (6 tons/mi2

) of nitrogen

and 29,460 tons (2 tons/mi2

) of phosphorus available

from animal waste. The Ouachita Mountains had an

estimated 57,555 tons (4 tons/mi2

) of nitrogen and

20,207 tons (2 tons/mi2

) of phosphorus available from

animal waste.

254
Fertilizers

Question 4.14: What are the current status and

potential effects of fertilizer applications on

aquatic resources within the Assessment area?

Fertilizers are a nonpoint source of nitrogen and

phosphorus. Most of the dissolved nitrogen that enters

streams from runoff of agricultural fertilizers occurs as

nitrate (Puckett 1994). Soil erosion may add considerable amounts of suspended phosphorus to streams

(Hem 1985). Trends in concentrations of nitrate and

total phosphorus at sites in river basins in the United

States were investigated by Smith and others (1987) and

Smith and others (1993). Studies such as these demonstrate the effects of fertilizers on the concentrations of

nitrogen and phosphorus found at those sites.

 Key Findings

Ozark Plateaus Province

 1. In 1985, nitrogen fertilizer application rates for the

counties within the Ozark Plateaus ranged from an

estimated 0 to 12 tons/mi2

.

 2. Phosphorus fertilizer application rates in 1985 for

the counties within the Ozark Plateaus ranged from

an estimated 0 to 5 tons/mi2

.

Arkansas Valley

 1. In 1985, nitrogen fertilizer application rates for the

counties within the Arkansas Valley ranged from

an estimated 0 to 12 tons/mi2

.

 2. Phosphorus fertilizer application rates in 1985 for

the counties within the Arkansas Valley ranged

from an estimated 0 to 1 ton/mi2

.

Ouachita Mountains

 1. In 1985, nitrogen fertilizer application rates for the

counties within the Ouachita Mountains ranged

from an estimated 0 to 3 tons/mi2

.

 2. Phosphorus fertilizer application rates in1985 for

the counties within the Ouachita Mountains ranged

from an estimated 0 to 0.5 ton/mi2

.

Data Sources and Methods of Analysis

The Aquatic Team obtained the data used in the

discussion of fertilizer use in the Assessment area from

Alexander and Smith (1990). Their study included

nitrogen and phosphorus fertilizers commercially

available for farm and nonfarm applications. Fertilizer

applications were estimated from county-level totals.

For counties located along the boundary of the Assessment area or for counties included more than once

because of their position in multiple river basins, a

correction factor was applied based on the percentage

of the county within the Assessment area or river basin.

Patterns and Trends

Ozark Plateaus Province. Use of nitrogen and

phosphorus fertilizers in the Ozark Plateaus part of the

Assessment area has increased substantially since 1965.

Estimates (Alexander and Smith 1990) indicate that

uses of nitrogen and phosphorus fertilizers have increased 147 percent and 52 percent, respectively, from

1965 through 1985.

The application rates for nitrogen and phosphorus

fertilizer in the Ozark Plateaus are well below the

national median. Estimates of nitrogen and phosphorus

fertilizer application rates for 1985 were computed as a

ratio of fertilizer use to fertilized acreage. The national

median of nitrogen fertilizer application rate was 28 tons/

mi2

; median application rates by State ranged from 14 to

64 tons/mi2

. Nitrogen fertilizer application rates in 1985

for the counties within the Ozark Plateaus ranged from

an estimated 0 to 12 tons/mi2

. The national median of

phosphorus fertilizer application rate was 6 tons/mi2

;

median application rates by State ranged from 3 to 17

tons/mi2

. Phosphorus fertilizer application rates (1985) for

the counties within the Ozark Plateaus ranged from an

estimated 0 to 5 tons/mi2

 (Alexander and Smith 1990).

Fertilizer use differed substantially among the Ozark

Plateaus river basins (table 4.20). Annual nitrogen

fertilizer use in 1965 ranged from 0.49 ton/mi2

 in the

Upper St. Francis River Basin to 2.34 tons/mi2

 in the

Osage River Basin. In 1985, annual nitrogen fertilizer

use ranged from 1.24 tons/mi2

 in the Upper St. Francis

to 4.93 tons/mi2

 in the Osage River Basin. Nitrogen

fertilizer use in the Osage and the Neosho-Illinois River

Basins nearly equaled the combined total nitrogen

255
fertilizer use in the rest of the entire Ozark Plateaus

Province. Annual phosphorus fertilizer use in 1965

ranged from 0.13 ton/mi2

 in the Upper St. Francis to

0.62 ton/mi2

 in the Osage River Basin. In 1985, annual

phosphorus fertilizer use ranged from 0.22 ton/mi2

 in the

Upper St. Francis River Basin to 0.86 ton/mi2

 in the

Osage River Basin. As with nitrogen fertilizer use,

nearly half of the total phosphorus fertilizer used in the

Ozark Plateaus was applied in the Osage and NeoshoIllinois River Basins.

The physiographic area with the largest nitrogen

fertilizer use in 1985 was the Mississippi Alluvial Plain

(about 8 tons/mi2

) followed by the Osage Plains (about

7 tons/mi2

), Salem and Springfield Plateaus (each about

3 tons/mi2

), and the Boston Mountains (about 2 tons/

mi2

). The largest phosphorus fertilizer use in 1985

occurred in the Mississippi Alluvial Plain and the Osage

Plains (each about 1 ton/mi2

), followed by the Springfield and Salem Plateaus (each about 0.5 ton/mi2

), and

the Boston Mountains (about 0.2 ton/mi2

).

Arkansas Valley. Fertilizer use in the Arkansas

Valley also has increased substantially. Fertilizer use

estimates (Alexander and Smith 1990) indicate that

nitrogen and phosphorus fertilizer use increased 233

percent and 62 percent, respectively, from 1965 to 1985

(table 4.20).

The application rates for nitrogen and phosphorus

fertilizer in the Arkansas Valley are well below the

national median. Estimates of nitrogen and phosphorus

fertilizer application rates for 1985 were computed as a

ratio of fertilizer use to fertilized acreage. The national

median of nitrogen fertilizer application rate was 28

tons/mi2

; median application rates by State ranged from

14 to 64 tons/mi2

. Nitrogen fertilizer application rates in

1985 for the counties within the Arkansas Valley

ranged from an estimated 0 to 12 tons/mi2

. The national

median of phosphorus fertilizer application rates was 6

tons/mi2

; median application rates by State ranged from

3 to 17 tons/mi2

. Phosphorus fertilizer application rates

in 1985 for the counties within the Arkansas Valley

ranged from an estimated 0 to 1 ton/mi2

 (Alexander and

Smith 1990).

Ouachita Mountains. Fertilizer use in the Ouachita

Mountains part of the Assessment area also has

Table 4.20—Estimated nitrogen and phosphorus fertilizer use by major river basin, 1965 and 1985

Nitrogen fertilizer Phosphorus fertilizer

River basin 1965 1985 Increase 1965 1985 Increase

 Acres Tons per square mile Percent Tons per square mile Percent

Ozark Plateaus

Upper Black 5,435,238 1.27 3.05 140 0.33 0.47 42

Gasconade 2,180,647 1.27 3.22 153 0.34 0.56 65

Meramec 2,553,402 0.79 1.89 139 0.21 0.33 57

Neosho-Illinois 5,948,454 1.50 4.13 175 0.42 0.68 62

Osage 6,332,800 2.34 4.93 110 0.62 0.86 39

Upper St. Francis 849,216 0.49 1.24 153 0.13 0.22 69

Upper White 7,170,362 0.83 2.45 195 0.21 0.36 71

Arkansas Valley

Arkansas River 8,225,920 0.48 1.60 233 0.13 0.21 62

Ouachita Mountains

Kiamichi-Little 3,874,560 0.24 1.25 421 0.07 0.18 157

Ouachita-Saline 4,555,520 0.20 0.94 370 0.05 0.12 140

Source: Alexander and Smith (1990).

256
increased substantially since 1965 (table 4.20). Fertilizer

use estimates (Alexander and Smith 1990) indicate that

nitrogen and phosphorus fertilizer use increased 396

percent and 149 percent, respectively, from 1965 to

1985.

The application rates for nitrogen and phosphorus

fertilizer in the Ouachita Mountains are well below the

national median. Estimates of nitrogen and phosphorus

fertilizer application rates for 1985 were computed as a

ratio of fertilizer use to fertilized acreage. The national

median of nitrogen fertilizer application rate is 28 tons/

mi2

; median application rates by State ranged from 14 to

64 tons/mi2

. Nitrogen fertilizer application rates in 1985

for counties within the Ouachita Mountains ranged from

an estimated 0 to 3 tons/mi2

. The national median of

phosphorus fertilizer application rate was 6 tons/mi2

;

median application rates by State ranged from 3 to 17

tons/mi2

. Phosphorus fertilizer application rates in 1985

for counties within the Ouachita Mountains ranged from

an estimated 0 to 0.5 ton/mi2

 (Alexander and Smith

1990).

Urbanization

Question 4.15: What are the current status and

potential effects of urbanization on aquatic

resources within the Assessment area?

Increases in the human population serve as an

indicator of the many environmental stresses resulting

from urbanization. Construction, sewage treatment

facilities and other utilities, changes in runoff patterns

from pavement and other impervious artificial surfaces,

and stream channelization (cleaning, straightening, and/

or paving stream banks) are all activities or actions

associated with urbanization that have the potential to

stress or damage aquatic ecosystems (Lull and Sopper

1969).

 Key Findings

 1. The 1990 population of the Assessment watersheds

was 3,361,301.

 2. Between 1980 and 1990, an 8 percent population

increase occurred within the Assessment watersheds.

 3. Twenty-four watersheds experienced population

increases of 7 percent or more between 1980 and

1990.

 4. Between 1980 and 1990, the rate of urbanization

was greater within the Assessment area than

nationwide.

 5. Two Assessment area watersheds (the Upper

Little River in southeastern Oklahoma and the

Little Missouri in southern Arkansas) had a 7

percent decrease in population from 1980 to 1990.

Data Sources and Methods of Analysis

The Aquatic Team obtained data from the “Surf Your

Watershed” Web site (U.S. EPA 1997a). To estimate

population and population density for each watershed,

the EPA used the internal point of each U.S. Census

block group to locate it within a specific watershed

(hydrologic unit with an eight-digit code). Each block

group was then associated with a specific watershed.

The block groups for each watershed were then combined to form an area roughly, but not exactly, equal to

the watershed area. Population density was computed

by dividing the total watershed population by the approximate watershed area. Percent changes in populations from 1980 to 1990 were computed by the following

equation (pop90-pop80)/pop80 (U.S. EPA 1997a).

Any watershed that had a decline in population

between 1980 and 1990 or had a population density of

less than 6.88 persons/mi2

 was placed in a “no change”

category. Population density values less than 6.88

persons/mi2

 are considered to be low enough to pose

minimal impacts on water quality.

If a watershed had greater than 6.88 persons/mi2

 and

a population change between 0 and 7 percent, it was

placed in the category “0 to 7 percent increase” (fig.

4.13). All watersheds with changes greater than 7

percent were grouped in the “greater than 7 percent

increase” category (U.S. EPA 1997a).

257
Figure 4.13—Human population changes from 1980 to 1990 by watershed (U.S. EPA 1997a).

Oklahoma

Arkansas

Missouri

Population change, 1980–1990

> 7% increase

0 to 7% increase

No change

> 7% decrease

Patterns and Trends

The 1990 population of the Assessment watersheds

was 3,361,301 (table 4.21). Between 1980 and 1990,

there was an overall population increase of 8 percent

(rounded) within the Assessment watersheds. Of the 50

watersheds, 24 had population increases greater than 7

percent between 1980 and 1990; 4 watersheds had

increases in population equal to or greater than 19

percent. The aquatic systems within these watersheds

have a greater vulnerability or potential to be stressed

and possibly damaged as a result of this increased

urbanization. Nationwide, 30 percent of the 2,202

watersheds had population increases greater than 7

percent in the same decade. Within the Interior Highlands area, 48 percent of the watersheds had population

increases greater than 7 percent in the same decade.

Between 1980 and 1990, the rate of urbanization was

greater within the Assessment area than nationwide

(U.S. EPA 1997a).

Two Assessment area watersheds (the Upper Little

River in southeastern Oklahoma and the Little Missouri

River in southern Arkansas) had a 7 percent decrease

in population from 1980 to 1990. This trend suggests

258
Table 4.21—Human population and percent change in population from 1980 to 1990,

by watershed

River basin Watershed 1980 1990 Change

Watershed name code (HUC) population population (rounded)

 Percent

Osage River Basin

H.S. Truman Reservoir 10290105 19,058 19,367 2

Sac 10290106 76,878 81,269 6

Pomme de Terre 10290107 23,710 27,199 15

South Grand 10290108 75,118 85,335 14

Lake of the Ozarks 10290109 44,392 53,616 21

Niangua 10290110 23,738 27,287 15

Lower Osage 10290111 26,525 28,658 8

Gasconade River Basin

Upper Gasconade 10290201 65,988 66,910 1

Big Piney 10290202 16,455 17,334 5

Lower Gasconade 10290203 23,111 23,416 1

Meramec River Basin

Meramec 07140102 277,030 311,029 12

Bourbeuse 07140103 40,175 45,200 13

Big 07140104 71,448 81,248 14

Upper St. Francis River Basin

Upper St. Francis 08020202 36,607 40,186 10

Neosho-Illinois River Basin

Lake O’ the Cherokees 11070206 51,354 52,130 2

Spring 11070207 209,541 218,000 4

Elk 11070208 45,463 56,154 24

Lower Neosho 11070209 77,081 80,382 4

Illinois 11110103 140,648 163,593 16

Arkansas River Basin

Dirty-Greenleaf 11110102 55,840 57,203 2

Robert S. Kerr Reservoir 11110104 117,905 125,602 7

Poteau 11110105 71,516 77,522 8

Frog-Mulberry 11110201 42,879 46,952 9

Dardanelle Reservoir 11110202 62,365 70,704 13

Conway-Point Remove 11110203 64,988 79,624 23

Petit Jean 11110204 17,395 19,069 10

Cadron 11110205 21,096 24,569 16

Fourche La Fave 11110206 8,119 8,409 4

Lower Arkansas-Maumelle 11110207 303,968 308,855 2

Kiamichi-Little River Basin

Kiamichi 11140105 18,878 19,009 1

Upper Little 11140107 28,691 26,614 -7

Mountain Fork 11140108 10,980 11,129 1

Lower Little 11140109 42,366 41,855 -1

Ouachita-Saline River Basin

Ouachita Headwaters 08040101 74,811 77,035 3

Upper Ouachita 08040102 52,122 51,657 -1

Little Missouri 08040103 34,289 31,992 -7

Upper Saline 08040203 68,403 78,750 15

Upper White River Basin

Beaver Reservoir 11010001 84,541 94,184 11

James 11010002 181,014 215,140 19

Bull Shoals Lake 11010003 73,781 83,049 13

Middle White 11010004 47,337 49,301 4

Buffalo 11010005 14,520 13,747 -5

North Fork White 11010006 31,979 36,389 14

Little Red 11010014 55,828 60,423 8

(continued)

259
that aquatic resources within these watersheds had

decreased vulnerability or potential to be stressed by

urbanization.

Implications and Opportunities

Increases in population can mean many things to a

watershed. There may be a demand for new home

construction, or land uses within the watershed may

shift from forested or rural to urban. Increased demands

for roads, schools, sewage treatment plants, water

supplies, and solid waste disposal may occur. In step,

the tax base may increase sufficiently to meet these

new demands and even improve inadequate existing

facilities. The Aquatic Team felt there were too many

factors involved related to the effects of urbanization to

draw reasonable implications.

In areas of population increases, national forest lands

can reasonably anticipate increases in demand and

requests for recreational opportunities, special use

permits, firewood harvesting, and access to public lands.

Mineral Extraction

Question 4.16: What are the current status and

potential effects of activities associated with the

exploration and extraction of minerals on

aquatic resources within the Assessment area?

The Assessment area is rich in mineral diversity,

which includes lead, zinc, quartz crystal, natural gas,

coal, and various stones. The national forests in the

Assessment area are important sources for many of

these minerals. Chapter 7 of the Ozark-Ouachita

Highlands Assessment: Social and Economic Conditions (USDA FS 1999a) discusses the significance and

value of these mineral resources.

Extractions of some mineral resources have adversely affected aquatic systems within the Assessment

area. Effects of mining-related extraction activities

primarily come from two sources: (1) increased sediment discharges into streams from present-day operations and (2) runoff waters leaching metals and chemicals into streams from abandoned, unreclaimed mines

and ore tailings left by historical operations. (The

historical operations took place before modern environmental laws were enacted.)

Table 4.21—Human population and percent change in population from 1980 to 1990,

by watershed (continued)

River basin Watershed 1980 1990 Change

Watershed name code (HUC) population population (rounded)

 Percent

Upper Black River Basin

Upper Black 11010007 55,366 55,303 0

Current 11010008 32,102 31,801 -1

Lower Black 11010009 19,322 19,206 -1

Spring 11010010 40,065 40,093 0

Eleven Point 11010011 14,853 14,705 -1

Strawberry 11010012 12,885 13,097 2

Total 3,104,524 3,361,301 8

HUC = hydrologic unit code.

Source: U.S. EPA (1997a).

260
 Key Findings

 1. In 1996, approximately 692 mining-related operations for hardrock and coal extraction occurred in

the Assessment area.

 2. The primary mining activity in the Assessment area

is surface mining of common variety minerals that

generally go to the building and road construction

industries.

 3. Several abandoned, historical mine sites continue to

contribute to chemical and metal leachates and

runoff, increasing acidity in some cases and

affecting aquatic resources within the Assessment

area.

 4. Effects on aquatic resources from present-day

mining activities are primarily associated with

increased sedimentation of streams caused by

instream gravel and sand extraction.

 5. Approximately 595 mi of rivers, streams, and lakes

are impaired as a result of mining activities within

the Assessment area.

Data Sources and Methods of Analysis

The Aquatic Team developed a data base for the

Assessment area mines from seven data bases obtained

from (1) the U.S. Department of Labor, Mine Safety and

Health Administration (MSHA); (2) the three State mine

permitting and regulating agencies; and (3) Forest Service

records for the Ouachita, Ozark-St. Francis, and Mark

Twain National Forests. These data are used throughout

this section as the basis for discussions of mine and

mining-related statistics, mine locations by counties, and

mineral commodities within the Assessment area in 1996.

Chapter 7 of this Assessment’s Social and Economic

Conditions (USDA FS 1999a) provides further details on

how the data base was developed and used.

Water quality data were obtained from the State

305(b) reports for Arkansas, Missouri, and Oklahoma

(AR DPCE 1996, MO DNR 1994, OK DEQ 1996).

These reports show the type and cause of effects on

aquatic resources in each State. Each State took a

slightly different approach to evaluating overall water

quality issues. However, enough similarities exist in the

State reports for them to complement each other. To

produce an analysis of the effects of mining activities on

the aquatic resources in the Assessment area, the

Aquatic Team compared locations and types of mines in

each of the Assessment watersheds with the States’

information on affected aquatic resources.

Patterns and Trends

In 1996, approximately 692 mining-related operations

for hardrock and coal extraction occurred in the

Assessment area (table 4.22). The largest number of

operations extracted common variety minerals such as

building stone and aggregate materials, sand and gravel,

and clay. The extraction of this commodity group

caused the most major and minor effects on water

quality in the Assessment area.

Table 4.22—Number of mining-related operations for selected mineral commodity groups in

the Assessment area in 1996

Mineral commodity group Number

Hardrock and coal

Common variety mineral materials (stone, aggregate, sand and gravel, clay) 535

Quartz (quartz crystal and #1 industrial grade quartz) 58

Coal 43

Industrial minerals (barite, novaculite, tripoli, cement, gypsum) 27

Metallic minerals (bauxite, lead, zinc, iron, vanadium) 23

Other gem minerals (diamond, wavellite, turquoise) 6

Gas and oil

Natural gas wells (producing) 6,426

Source: AR DPCE (1997), MO DNR (1997), OK DM (1996), USDA Forest Service (1996).

261
Many laws are concerned with the extraction of

these products precisely because of their impact on the

environment. In particular, the removal of instream

gravel that results in increased stream sediment and

turbidity is listed in the States’ water quality reports as

an “effects contributor” in 14 Assessment area stream

segments (AR DPCE 1996, MO DNR 1994, OK DEQ

1996). Gravel exploration and extraction are not relegated to a particular area or zone but occur on a

number of streams throughout the Assessment area.

Instream gravel removal is prohibited within Statedesignated extraordinary resource waters. Other

controls, such as the Arkansas Act 827 of 1991 that

requires a State permit for instream gravel removal

operations, result in operations with more environmental

accountability. The likely future trend throughout the

Assessment area will be fewer unregulated instream

gravel removal operations.

Arkansas, Missouri, and Oklahoma 305(b) reports for

1996 show the various activities affecting the quality of

aquatic resources within the Assessment area. Table

4.23 is a synopsis of the effects from both past and

present Assessment area mining activities and shows

that mineral exploration and development has affected

the area’s aquatic resources. The most common mining

activities were historic metal ore, coal, and instream

gravel extractions (AR DPCE 1996; MO DNR 1994,

1996b; OK DEQ 1996).

Several Assessment area watersheds have aquatic

resources that are still being affected by abandoned

lead-zinc and coal mines. Unregulated mining practices

took place at these sites between the early 1800’s and

mid-1900’s. Chemical runoff and leachates developing

from unused metals coming into contact with rainwater

have had an adverse effect on the pH of many of the

Assessment area watersheds.

The States’ water quality reports indicate how many

miles of Assessment area streams are affected by

mining activity (table 4.23). The “Impaired Waters”

section in this chapter shows, according to GIS data,

how many stream miles have been affected. Resource

extraction (mining) in Arkansas is noted in the 1996

Arkansas Water Quality Inventory Report (AR

DPCE 1996) as a “major effects contributor” to segments of four streams totaling 116 mi in length (Hurricane Creek, Lost Creek, Crooked Creek, and Kings

River). Resource extraction merits a “minor effects

contributor” rating for another 83.9 mi of stream

segments in three streams (James Fork, Illinois River,

and War Eagle Creek).

In Missouri, approximately 79 mi of streams in 10

watersheds are affected by past or present resource

extraction activities. Erosion of abandoned mine tailings

into streams has seriously affected 18.5 mi of classified

streams, including 3 mi that were severe enough to

preclude their use as aquatic habitat (MO DNR 1994).

The 1996 Oklahoma Water Quality Assessment

Report states that 23 streams and lakes (269 mi) are

partially affected by past or present mining-related

activities. These streams are within four Oklahoma

watersheds. Eighteen streams are located in the Lake

O’ the Cherokees system in Delaware, Craig, Mayes,

and Ottawa Counties. These streams are primarily

contaminated by acids from metal extraction that

occurred in the Oklahoma portion of the old Tri-State

Lead-Zinc Mining District between 1910 and the 1940’s

(OK DEQ 1996). Approximately 130 mi of the Lake O’

the Cherokees system are affected, including bays,

coves, and associated inlets and streams. Table 4.24

shows that approximately 595 mi of rivers, streams, and

lakes are impaired as a result of past or present mining

activities within the Assessment area.

Implications and Opportunities

Protecting the quality of aquatic resources is critical

to continued prosperity in the Interior Highlands. The

effects of historical mining operations continue to plague

parts of the Assessment area. Today’s environmental

awareness and improved extraction and reclamation

technologies are a vast improvement over the techniques of the past. Most present-day effects on aquatic

resources are from sedimentation resulting from operations taking place directly in streams. These are much

less harmful than the chemical runoff and harmful

leachates allowed by previous environmental regulations. Opportunities exist for continued cooperation

between State and Federal agencies and industry to

study and implement Assessment area reclamation

practices that have protected aquatic resources most

successfully.

262
Table 4.23—Mining-related effects on streams in the Assessment area by State, stream, and

watershed

Watershed

Stream code (HUC) Milesa Mining effectsb Effects contributorsc

Arkansas

Hurricane Creek 08040203 31 RE, minerals—major Historic mining: bauxite

Lost Creek 08040203 34 RE, minerals—major Historic mining: bauxite

James Fork 11110105 18 RE—minor

Illinois River 11110103 1.8 RE, S—minor

Illinois River 11110103 11 S—major, RE minor

Illinois River 11110103 22.5 S—major, RE—minor

Crooked Creek. 11010003 32 RE, S—major

War Eagle Creek 11010001 30.6 S—major, RE—minor

War Eagle Creek 11010001 28 RE, S—major

Kings River 11010001 19 RE, S—major

Missouri

Saline, Goose, Village 08020202 4 RE, S—major Historic mining: lead-zinc

Creeks

Osage River 10290111 0.2 D—minor

Osage River 10290111 0.2 D—minor

Barkers, tributary 10290108 1 A—minor Historic mining: coal

Tebo Creek, east 10290109 2.5 A Historic mining: coal

Tebo Creek, mid 10290110 9 A Historic mining: coal

Meramec River 07140102 0.2 D—minor

Meramec River 07140102 0.2 D—minor

Shibboleth Creek 07140104 0.5 S—minor

Big, Flat River, Shaw 07140104 45 M—major, S—minor Historic mining: lead-zinc

Branch

Black River 11010007 0.2 D—minor

Center Creek 11070207 11 M—major & minor Historic mining: lead-zinc

Turkey Creek 11070208 3 M—major & minor Historic mining: lead-zinc

Grove Creek 11070209 2 M—major & minor Historic mining: lead-zinc

Oklahoma

Lake O’ the Cherokees 11070209 130d RE—minor

Sans Bois Creek 11110104 38d AM—minor

Beaver Creek 11110104 15d PA—minor

Sallisaw Creek 11110104 38d AM—minor

Arkansas River 11110104 19d OP—minor

Brazil Creek 11110105 29d OP—minor

HUC = hydrologic unit code; RE = resource extraction; PA = petroleum activities; AM = abandoned mine

tailings; S = siltation; OP = open pit; M = metals; D = dredging; A = acidity.

a Stream miles actually impaired as reported in the States’ 1996 Water Quality Reports. See the “Impaired

Waters” section of Chapter 4 for numbers taken from Geographic Information System data. b Major and minor effects on aquatic resources from mine-related contributions.

c State listed contributors to effects on aquatic resources.

d Approximate stream length.

Source: AR DPCE (1996), MO DNR (1994, 1996b), OK DEQ (1996).

263
Introduced Species

Question 4.17: What effects are introduced

aquatic species having on the Assessment area?

Burr and Warren (1986) define “introduced species”

as an individual, group, or population of organisms that

occur in a particular locale due to human actions that

inadvertently or deliberately moved the species from

one place to another. They further categorized these

introductions as “exotic”—a species introduced from a

foreign country whose entire native range is outside the

country where found—and “transplanted”—a species

moved outside its native range but within a country

where it occurs naturally. These two categories were

further described as: (1) established—an introduced

species with a permanent population that is unlikely to

be eliminated by human or natural causes; (2) possibly

established—an introduced species without the status of

a permanent population but reproducing in an area

where its elimination by humans would be impractical;

(3) localized—a confirmed, reproducing population of an

introduced species that can be eliminated using standard

methods; and (4) reported—an introduced species

collected without evidence of reproduction. These

categories are used for individual species discussed in

this report.

 Key Findings

 1. Introduced species such as zebra mussels, common

carp, and a number of aquatic weeds have become

pests.

 2. Arkansas, Missouri, and Oklahoma are making

concerted efforts to retard the spread of zebra

mussels both through general public education and

the education of individual anglers and boaters.

 3. It is likely that zebra mussels eventually will show

up in most lakes and reservoirs in the Assessment

area as the result of a transient boating public.

Zebra mussels are expected to ravage the native

mussel fauna as well as disrupt the food chain of

any water body they colonize.

 4. Nonindigenous species (non-native or transplanted

species) require constant management attention to

reduce the likelihood of introduced species, particularly exotics (non-natives), becoming established.

Data Sources

The Geological Survey, Biological Resources Division, Gainesville, FL, provided the majority of the

information for “Introduced Species” from data bases

they maintain on nonindigenous aquatic species for the

United States. This data base is specific only by State.

The Geological Survey office furnished individual

species summaries, and the Aquatic Team accessed

their home page for additional species factsheets. For

more information, see their Web site at <http://

www.nfrcg.gov>.

Table 4.24—Stream miles impaired by historic, gravel, sediment, and other mining

activities by State

State Historic Instream gravel Sediment Other

 - - - - - - - - - - - - - - - - - - Stream miles - - - - - - - - - - - - - - - - - -

Arkansas 84.0 98.8 64.1 0

Missouri 77.5 1.0 0.5 0

Oklahomaa 130 0 86 53

a Oklahoma did not report actual stream reach distances; approximate stream lengths shown here.

Source: AR DPCE (1996), MO DNR (1994), OK DEQ (1996).

264
Patterns and Trends

The species lists maintained by the Geological

Survey, Biological Resources Division, reflect documented stockings over the course of this century and

earlier. Not all of these fish species can presently be

found in Assessment area waters. Since 1900, 46 fish

species have been introduced into Arkansas waters

(statewide, not just the Arkansas portion of the Assessment area) of which 20 are established and 10 are

either unknown or questionable as to their establishment. During the same time, Missouri has had 38 fish

species introduced with 15 established and 11 of questionable or unknown status, and Oklahoma has had 45

fish species introduced with 19 established and 18 of

questionable or unknown status. The differences

between total numbers introduced and established plus

questionable or unknown status reflect those introduced

species that did not develop reproducing populations.

The majority of these introduced species are game fish

stocked to provide recreational fishing. By virtue of

these fish being “moved,” they are classified as introduced species. While the green sunfish in a landlocked

pond is an introduced species, that same species would

not be considered “introduced” in another lake built on a

stream containing native green sunfish. Common carp,

established across the Nation for more than a century,

are still considered an established exotic even though

they are established in just about every water body

other than the coldest trout streams and most remote

mountain lakes.

Zebra mussels and Asian clams are the only two

exotic mussels established in the three States in the

Assessment area. Zebra mussels are present in the

Arkansas River in the Assessment area in Arkansas

and Oklahoma. Asian clams are present in aquatic

habitats throughout the Assessment area. The daphnia,

a zooplankton, is established in several reservoirs within

each State within the Assessment area. It too is an

established exotic. Arkansas has had 19 aquatic plant

introductions; Missouri, 18; and Oklahoma, 12—all of

which are established but not necessarily within the

Assessment area of the three States. The following

summaries provide information about species considered

most significant to the States in the Assessment area.

More details on these species are available from the

earlier referenced Geological Survey Web site.

Asian or Asiatic clams. This mussel species can be

found throughout Arkansas in such rivers as the Arkansas, Boeuf, Little, Ouachita, Red, Spring, St. Francis,

Strawberry, Sulphur, and White. Similar widespread

distribution also occurs in Missouri. This mussel has

been found in the following Missouri rivers: Big, Black,

Bourbeuse, Little Black, Meramec, Mississippi, Missouri, Moreau, Osage, and St. Francis. In Oklahoma,

they have been found in the Arkansas, Little, and Red

Rivers, and in Lakes Overholser and Thunderbird.

According to Foster and Fuller (1997), Asian or Asiatic

clams are an established exotic from temperate to

tropical Southern Asia west to the Eastern Mediterranean; Africa, except in the Sahara desert; and Southeastern Asian islands south into Central and Eastern

Australia. They were first documented in this country in

1938 along the banks of the Columbia River near

Knappton, WA. The most prominent effect of the

introduction of the Asian clam has been biofouling,

especially of complex power plant and industrial water

systems, drinking water supplies, and irrigation canals

and pipes. It also alters benthic (lake or stream bottom)

substrate and competes with native species for limited

food and space. Densities of this species have been

documented in the thousands per square meter, often

dominating the benthic community.

Zebra mussels (Dreissena polymorpha). In

Arkansas, zebra mussels are flourishing in the Arkansas

River and can be found in the Mississippi and White

Rivers. In Missouri, this species is found in the Mississippi River only. In Oklahoma, it is found in the Arkansas and Verdigris Rivers. Every year the densities at

measured sites continue to increase.

According to the Geological Survey, Biological

Resources Division (USDI GS BRD 1997b), this

species is an established exotic originating from the

Balkans, Poland, and the former Soviet Union. They

were first discovered in North America in 1988; by

1990, zebra mussels had been found in all of the Great

Lakes. In 1991, they escaped the Great Lakes Basin

and found their way into the Hudson and Illinois Rivers.

The Illinois River was their avenue to expansion into the

Mississippi River drainage. Their rapid advance through

the Mississippi River drainage is attributed to barge

traffic. It is theorized that mussels attached to barge

hulls were scraped or fell off during routine navigation

of the Mississippi and major tributaries. Overland

265
dispersal occurs when people move boats via trailer

from contaminated to uncontaminated waters (zebra

mussels adhere to boat hulls and motors). Live zebra

mussels have been found on two houseboats in Lake

Ouachita that were recently moved there from the

Arkansas River.

Zebra mussels are fouling water intake structures

and water lines at hydroelectric and nuclear power

plants, public water supply plants, and industrial facilities. Navigational and recreational boating is affected by

increased drag due to attached mussels. Smaller zebra

mussels can be sucked into engine cooling systems,

causing overheating and damage. Navigational buoys

have reportedly sunk from the weight of attached zebra

mussels. Continued attachment of zebra mussels can

cause corrosion of steel and concrete affecting its

structural integrity. Navigation locks in the Arkansas

River system are being cleaned of mussels at great

expense. Zebra mussels also attach themselves to the

hard surfaces of native mussels. Some native mussel

shells have more than 10,000 zebra mussels attached to

them. The more rare native mussels species are not

likely to survive the smothering by zebra mussel attachments or the competition for limited food resources. The

fact that under cool, humid conditions, zebra mussels

can stay alive for several days out of the water makes

them even more dangerous to native populations. It is

expected that zebra mussels will upset the food chain

for other species as well.

The high population levels of zebra mussels and their

filter-feeding habits reduce plankton availability for other

species and increase light penetration that stimulates

growth of aquatic vegetation. The resulting decline of

smaller, plankton-dependent fish will likely diminish the

prey base (food chain) for recreational fish species; and

consequently their populations will also decline. Clearing

the water column of plankton can also lead to increased

aquatic vegetation beds where sunlight can penetrate to

lake bottoms. Aquatic vegetation beds provide cover

and act as nurseries for some species of fish. If they

become excessive, they can upset predator and prey

relationships and diminish recreational fisheries. Excessive vegetation beds can also seriously hamper fishing

from the shore and, if extensive enough, may seriously

impact boating. Arkansas, Missouri, and Oklahoma are

making concerted efforts to retard the spread of zebra

mussels through general public education and, more

specifically, through the education of anglers and

boaters. Zebra mussels are likely to show up eventually

in most lakes and reservoirs with a transient boating

public, but the slowing of the spread of zebra mussels is

worth the effort. At this time, no control measures are

known for eradicating the species in the wild, but

scientists continue to investigate possible control

measures.

Daphnia lumholtzi. An established exotic from

tropical and subtropical lakes in east Africa, east

Australia, and the Asian subcontinent of India (USDI

GS BRD 1997a), Daphnia lumholtzi has been found in

Lake Dardanelle in Arkansas; Robert S. Kerr Reservoir, Ten Killer Ferry, and Lake Texoma in Oklahoma;

and Harry S. Truman, Harrisonville, Stockton, Nehai,

Tonkayea, Montrose, Pomme De Terre, Lake of the

Ozarks, Monroe, Bull Shoals, Norfork, Mark Twain,

Thomas Hill, and Atkinson Reservoirs in Missouri. The

impacts of this invader are not yet known. One recent

study indicates it does not appear to be displacing other

daphnia species in the Norris Reservoir. It also has not

shown up in stomach samples of fish from the same

reservoir. It may be too soon to detect the ecological

effects of this exotic on aquatic habitats in the Assessment area.

Grass carp or white amur (Ctenopharyngodon

idella). This species of carp is an established exotic

from eastern Asia (from the Amur River of eastern

Russia and China south to the West River of Southern

China). Both authorized and unauthorized stockings of

grass carp have taken place in the United States for

biological control of unwanted aquatic vegetation. These

carp were introduced into the United States in 1963 at

Auburn, AL, and Stuttgart, AR. The first release of this

species into open waters took place at Stuttgart, AR,

when fish escaped the Fish Farming Experimental

Station. The species spread rapidly thereafter as a result

of widely scattered research projects, agency stockings,

interstate distributions from private hatcheries by

individuals, and natural dispersal from stocked sites.

Nico and Fuller (1997) have documented the reproduction of grass carp populations in the following rivers:

Mississippi, Missouri, Illinois, Ohio, and Trinity (in

Texas). Grass carp have a short gut and can digest only

50 percent of the up to 100 lbs of plant material they eat

266
each day. The undigested portion is excreted and

therefore enriches the aquatic habitat and promotes

algal blooms. These blooms can reduce water clarity

and decrease oxygen levels. Removal of aquatic

vegetation by carp can have negative effects on native

fish through the elimination of food sources, shelter, and

spawning substrates supported by the vegetation. On

the other hand, grass carp are used extensively for

aquatic vegetation control when vegetation becomes

excessive and begins to seriously interfere with boating

and fishing. At low population densities, grass carp may

feed on preferred rather than on target plant species.

Grass carp may also reduce aquatic vegetation that is

desirable for waterfowl and other wildlife species. It is

believed that grass carp imported from China were the

source of the introduced Asian tapeworm Bothriocephalus opsarichthydis; these carp are known to have

spread the parasite to other fish in Arkansas. The

stocking of grass carp is not prohibited in Arkansas,

Missouri, and Oklahoma.

Eurasian or spike water milfoil (Myriophyllum

spicatum). This milfoil is one of the most widely

distributed of the exotic aquatic plants; it now occurs in

42 States. It has become a significant problem in

Missouri’s Lake of the Ozarks and Bootheel region

water bodies. In Oklahoma, it is well established in

reservoirs in Stevens, Sequoyah (within the Assessment

area), and Cleveland Counties. It has been a major

nuisance in the Kerr Reservoir. The first report of this

species’ presence in Arkansas came, most recently,

from Lake Ouachita. In the lakes, reservoirs, and ponds

it invades, the milfoil’s abundant growth usually causes

problems such as the displacement of native vegetation.

The best method for minimizing dispersal and impacts of

this aggressive, submerged plant is to prevent inadvertent transfer of milfoil from one water body to another

on the motors of trailers and boats.

Purple loosestrife (Lythrum salicaria). Predominantly occurring in the northeastern corner of Missouri,

most populations of purple loosestrife are located around

the edges of lakes and ponds. A single stand was

reported in 1985 in Craighead County in northeastern

Arkansas; however, it has not been verified if this

reported occurrence still exists. In Oklahoma, an

isolated population has been reported since 1992 at a

roadside location in Oklahoma City. These reported

occurrences are outside the Assessment area. Purple

loosestrife is responsible for large-scale deterioration of

wetlands and loss of wildlife habitat throughout the

Northern and Northeastern United States. This species

can be found as far south as the piney woods region of

east Texas. Recent reports have also been received of

occurrences in Tennessee Valley Authority (TVA) lakes

and streams.

Other aquatic problem plants. The following 10

aquatic plants (in alphabetical order) have also been

reported in the Assessment States as causing problems.

Each is discussed briefly.

• Alligatorweed (Alternanthera philoxeroides) is

found throughout southeastern Arkansas where it

ranges as far north as Perry County (within the

southern quarter of the Assessment area). The

species was recently identified in Oklahoma within

the Lower Verdigris watershed in Wagoner County

just to the west of the Assessment area. Usually

found emerging from the edges of lakes, streams,

and ditches, alligatorweed is a problem aquatic plant

in the Southern States.

• Bog bulrush (Scirpus mucronatus) is a relatively

new Eurasian species introduction to the Midwest.

Bog bulrush has been collected from ponds in eastern

Missouri.

• Brazilian waterweed (Egeria densa) has been

reported in the Eleven Point River of Missouri and is

expected to eventually appear throughout the Eleven

Point and other watersheds in the Missouri Ozarks.

This species is established in southern Oklahoma and

central Arkansas and is well known as a pest in lakes

and streams in 30 States nationwide.

• Brittle naiad or waternymph (Najas minor) is

abundant in areas of the Missouri Bootheel and in the

Lake of the Arbuckles, Murray County, OK. An

aggressive weed in many States, brittle waternymph

thrives in impounded and polluted areas. It is common in Tennessee reservoirs of the TVA. Native

Najas species are often dominated by brittle

waternymph.

• Creeping yellowcress (Rorippa sylvestris) has been

reported in swampy woods and wet ditches along the

Mississippi River in Missouri and in Arkansas. This

species has also been reported in moist, rocky banks

of Hickory Creek in western Missouri. Creeping

267
yellowcress forms spreading, massive colonies in wet

or riverine environments by budding from the roots.

• Curly pondweed (Potamogeton crispus) currently

occurs in springs, lakes, and ponds throughout

Missouri. Occurrences of it have been reported in a

dozen counties in Oklahoma, including Cherokee and

Bryan, and in northwest Arkansas. Curly pondweed

is very aggressive in aquatic habitats in the northern

regions of the United States.

• Dotted duckweed (Spirodela punctata) is reported

in ponds in the western and southwestern areas of

Missouri and throughout Oklahoma. In the Southeastern United States, dotted duckweed can blanket

ponds, competing with native Lemna species and

blocking light to other submersed plant species.

However, dotted duckweed is sensitive to long

periods of cold temperatures and may be expected to

occur only in localized areas of the Assessment area.

• European waterclover (Marsilea quadrifolia) is

spreading westward from the Northeastern United

States and has been reported in northern Missouri. In

1985, this species’ southernmost range was within

the Lower Missouri-Morreau watershed. At that

time, the native Marsilea vestita (listed as endangered in Missouri) was no longer found within the

State.

• Watercress (Rorippa nasturtium-aquaticum) is

found throughout the temperate United States. It is

found in Missouri, Oklahoma, and Arkansas where it

can dominate the vegetation of cold water springs

and streams and lakeshores.

• Yellow floatingheart (Nymphoides peltata) forms

dense mats covering ponds and stream channels and

is prevalent in southern Oklahoma. Occurrences of

this species have additionally been reported in

northwest Arkansas and in Missouri.

Implications and Opportunities

Introduced aquatic species have the potential to

seriously disrupt indigenous aquatic fauna and flora.

However, as in the case of largemouth bass and

bluegill, some stockings can be quite beneficial. As

discussed in “Commercially and Recreationally Important Species” in Chapter 2, a number of species have

been successfully introduced, resulting in tremendous

benefit to fisheries. These are examples of species,

native to this Nation, being stocked into aquatic systems

with either natural predators or the fisheries management resources needed to limit any negative impacts.

Exotic aquatic species introductions—either accidental

or the result of well-intentioned actions—have resulted

in environmental calamities of varying magnitudes.

All planned introductions (even native, but particularly exotic species) need to be well researched and

thought out in advance and thoroughly reviewed before

implementation. All applicable laws, executive orders,

regulations, and governmental and scientific organizational policies should be examined prior to approving

nonindigenous species introductions. Potential genetic

impacts of such introductions on indigenous species

should also be considered when deciding the merits

and sources of fishes to use in introductions (such as

are being considered in the three Assessment area

States for walleye, sauger, and smallmouth bass; see

Chapter 2, “Commercially and Recreationally Important

Species”).

Measures to educate the public about the devastation

caused by zebra mussels and nonindigenous aquatic

plant introductions must continue and may need to be

expanded and intensified. Once many of these introduced species become established, they simply cannot

be controlled, let alone eliminated. Prevention is the

strongest recourse. It is clear that more research on

methods to control zebra mussels and protect native

mussel fauna in the Assessment area is needed.

Where not already in place, State and Federal

agencies should develop and use protocols that would

help prevent the spread of introduced species. For

instance, fisheries sampling equipment is a prime

candidate for spreading unwanted species if not decontaminated properly between uses in affected and

unaffected water bodies.

Efforts to track the spread of introduced species

should continue and all information updates kept current

and easily accessible. A central clearinghouse for this

information (such as that provided by the Geological

Survey) is very useful at the national level. Similar,

additional State-level clearinghouses would be very

helpful.

268
Chapter 5: Water Supply and Use

The Ozark-Ouachita Highlands encompass headwaters for 13 major rivers (the Gasconade, Meramac, St.

Francis, Neosho, Illinois, White, Black, Kiamichi, Little,

Ouachita, and Saline Rivers, and portions of the Arkansas and Osage Rivers). These rivers serve instream and

offstream water needs for much of the South-Central

United States. Streamflow from these rivers eventually

empties into the Mississippi River. The purpose of this

chapter is to compare water supply with past and

present water uses in the Assessment area and examine

trends in uses that may occur in the future.

Past and Present Supply and Use

Question 5.1: What are the past and current

water supplies and uses in the Assessment area?

Currently, the supply of water in the Highlands vastly

exceeds use in most areas. In a few locations, however,

use has risen to consume a substantial portion of the

supply.

 Key Findings

 1. Total withdrawals of water in the Assessment area

in 1995 were 6,622 million gallons per day (gal/d).

Of these withdrawals, 1,322 million gal/d (20

percent) were consumed and not returned to a

stream.

 2. Twenty-two percent of the total 1995 withdrawals

came from ground water pumping; the other 78

percent of withdrawals came from surface water.

 3. Hydropower plants used almost 103 billion gal/d of

surface water to produce electricity.

 4. From 1985 to 1995, withdrawals increased in four

categories of offstream water use (domestic and

public, commercial, thermoelectric, and irrigation)

and decreased in three other categories (industrial,

mining, and livestock).

 5. Increases in withdrawals, especially those at

thermoelectric plants and for irrigation, far outpaced decreases, resulting in substantial net

increases.

 6. In 1995, 64 percent of withdrawn water was for

cooling at thermoelectric plants; another 20 percent

was for crop irrigation.

 7. Annual precipitation in the Assessment area

averages about 44 inches, of which roughly 70

percent evaporates. The rest is available as

streamflow, to recharge ground water reservoirs, or

for offstream use.

 8. Across the entire area in the average year, only 6.7

percent of the 53.7 billion gal/d of water yield is

withdrawn for offstream use, and only 1.2 percent

is consumed.

 9. Withdrawals vary widely across watersheds and

exceed 20 percent of available water in four

watersheds. In three of these watersheds (South

Grand, Illinois, and Dardanelle Reservoir), withdrawals for thermoelectric plants account for 83 to

97 percent of total withdrawals. In the other

watershed (Lower Black), irrigation accounts for

97 percent of total withdrawals.

Comparisons of Water Supply and Use

Data Sources and Methods of Analysis

The USDI Geological Survey has estimated the

Nation’s water use at 5-year intervals since 1950. Early

estimates were for whole States and even larger

watersheds. In 1985, however, the agency began

estimating use for counties and watersheds (hydrologic

units) that tend to be slightly larger than a typical

county. State totals for these periodic surveys of water

use have been published in Geological Survey circulars;

for example, the 1990 data are found in Solley and

others (1993). The Geological Survey also provides

detailed water use and supply estimates as data files.

For this report, the Aquatic Team summed estimates of

water use and supply for counties and watersheds

within the aquatic study area. Estimates are reported

269
for various water uses including domestic, municipal,

industrial, agricultural (for irrigation), thermoelectric

(largely for cooling), and hydroelectric uses. All uses

except hydroelectric involve offstream withdrawals. Of

the water withdrawn, a portion is consumed (e.g., by

being incorporated into a product or evaporated from an

irrigated field) and is removed from the immediate

water environment; the remainder returns to the stream

or perhaps seeps into ground water storage where it is

available to be used again. The other principal data for

this report are estimates of water supply. The team

estimated supply by subtracting evapotranspiration from

precipitation using monthly data from 1962 to 1988. The

team estimated precipitation from data of weather

stations within the Assessment area. Evapotranspiration

was estimated using the Complementary Relationship

Areal Evapotranspiration model (Morton 1965, 1983),

which is based on the complementary relation between

potential and actual evapotranspiration (Bouchet 1963).

This model uses meteorological data including precipitation, humidity, solar radiation, albedo (reflectivity of the

Earth’s surface), and temperature. These data were

mapped spatially using Geographic Information System

technology, and missing data points were then estimated

by interpolation to achieve a grid cell size of 10 kilometers (km) for input to the model. Claessnes (1996)

describes the complete methodology. To verify the

model’s accuracy, model estimates of average annual

evapotranspiration were compared with estimates

computed as precipitation minus runoff for 164 relatively undisturbed watersheds in the United States. The

average error in estimation across these watersheds

was less than 2 percent of average annual precipitation

(Claessnes 1996).

The Aquatic Team projected future withdrawals in

the Assessment area based on county-level estimates

of future population and income to the year 2040

provided by the USDC’s Bureau of Economic Analysis

(USDC BEA 1992) and on assumptions about rates of

change in other factors affecting water use. These

assumed rates of change, listed below, are based on an

assessment of national water uses over the past 35

years (Brown 1998). The rates of change are applied

to the 1995 withdrawal levels of the Assessment area.

Patterns and Trends

Counties. The Assessment area comprises major

portions of Arkansas and Missouri plus a small section

of Oklahoma. Water withdrawals in Arkansas and

Missouri have risen sevenfold since 1950 (fig. 5.1).

Withdrawals within the Assessment area have also

risen. Rates of increase for the two States and for the

Assessment area have been similar since 1985; there

was about a 25 percent increase from 1985 to 1990

and about a 7 percent increase from 1990 to 1995.

Total withdrawals in the Assessment area in 1995

were 6,622 million gal/d (table 5.1). Of these withdrawals, 1,322 million gal/d (20 percent) were consumed.

Twenty-two percent of the total withdrawals came from

ground water pumping; the other 78 percent was

withdrawn from surface water. In addition, almost 103

billion gal/d of surface water were used to produce

electricity at hydropower plants.

Figure 5.1—Total water withdrawals in million gallons per day (Mgal/d) in Arkansas and Missouri

from 1950 to 1995, including 1985 to 1995 withdrawals in the Assessment area.

Assessment area

0

4,000

8,000

12,000

16,000

20,000

1950 1955 1960 1965 1970 1975 1980 1985 1990 1995

Mgal/d

270
Table 5.1—Fresh water uses in the Ozark-Ouachita Highlands, 1985–1995

Uses 1985 1990 1995

 - - - - - Million gallons/day - - - - -

Withdrawal

Domestic and public 440 464 538

Commercial 97 277 203

Industrial 139 114 136

Thermoelectric 2,947 3,901 4,234

Mining 29 26 11

Livestock 210 149 184

Crop irrigation 986 1,216 1,315

Total 4,847 6,148 6,622

Consumptive use 1,006 1,205 1,322

Hydroelectric water use 141,942 116,793 102,884

Source: Solley and others (1988, 1993).

Watersheds. Water availability and use were compared for watersheds within the Assessment area (table

5.3). Total withdrawals shown in table 5.3 are considerably less than those in tables 5.1 and 5.2 because the

watersheds included in table 5.3 omit some areas of high

water use on the perimeter of the Assessment area that

are included in the county-based tables.

Precipitation in the Assessment area averages about

44 inches (in.) annually, of which roughly 70 percent

evaporates; and the rest is available as streamflow to

recharge ground water reservoirs or for offstream use.

It should be noted that the model for computing evapotranspiration has a greater margin of error when used

for specific years than when used to estimate a mean

over several years, so these estimates must be used

with caution. Across the entire area in the average year,

only 6.7 percent of the 53.7 billion gal/d of water yield is

withdrawn for offstream use, and only 1.2 percent is

consumed. However, the portion withdrawn varies

widely across watersheds and exceeds 20 percent in

four watersheds. In three of these watersheds (South

Grand, Illinois, and Dardanelle Reservoir), withdrawals

for thermoelectric plants account for 83 to 97 percent of

total withdrawals. In the other watershed (Lower

Black), irrigation accounts for 97 percent of total

withdrawals. Note that because thermoelectric plants

return nearly all of their withdrawals to the stream,

Figure 5.2—Categories of water withdrawals in the Assessment area

for 1995.

Livestock

3%

Crop irrigation

20%

Domestic and

public

8% Commercial,

industrial, and

mining

5%

Thermoelectric

64%

From 1985 to 1995, withdrawals increased for four

categories of water use: (1) domestic and public,

(2) commercial, (3) thermoelectric, and (4) crop irrigation. Withdrawals decreased during this period for the

other three categories: (1) industrial, (2) mining, and

(3) livestock (table 5.1). Increases, especially those at

thermoelectric plants and for irrigation, far outpaced

decreases, resulting in substantial net increases.

In 1995, 64 percent of withdrawn water was for

cooling at thermoelectric plants, and another 20 percent

was for crop irrigation (fig. 5.2). Domestic and public

uses (public includes parks, government offices, and

firefighting) account for another 8 percent, with the

remaining 8 percent for commercial, industrial, mining,

and livestock.

Table 5.2 lists 1995 withdrawals by county and

shows that withdrawals for the largest water users

are unevenly distributed. Thermoelectric plants use

water in 15 of the 107 counties in the Assessment area

and very large amounts in 8 of those counties. The

eight counties with the large thermoelectric plants

account for 64 percent of the total Assessment area

withdrawals. Irrigation is more widespread but uses

very large quantities of water in only six counties.

Hydroelectric plants operate in 22 counties and use

enormous quantities of water, although nearly all of this

use occurs instream.

271
Table 5.2—Water use by State and county in 1995 in the Ozark-Ouachita Highlands

Offstream

withdrawal Offstream

Domestic thermo- withdrawal, Live- Crop

County and public Commercial Industrial electric mining stock irrigation Total Hydroelectric

 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Million gallons per day - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Arkansas

Baxter 2.73 1.23 1.23 0 0 0.34 0 6 999

Benton 11.77 0.94 0.94 319.27 0 2.92 0.45 336 0

Boone 2.71 0.36 0.35 0 0 1.15 0.03 5 0

Carroll 2.91 1.45 1.45 0 0.01 1.44 0.02 7 8,073

Clark 2.20 0.57 1.10 0 0 0.33 0.96 5 337

Cleburne 3.95 0.24 0.13 0 0 2.37 0.10 7 848

Conway 1.55 0.16 20.66 0 0 1.62 4.55 29 0

Crawford 12.33 1.22 1.66 0 0 0.62 0.06 16 0

Faulkner 7.38 1.48 1.48 0 0 0.93 0.63 12 0

Franklin 2.64 0.40 0.32 8.23 0 0.89 0.08 13 15,018

Fulton 1.00 72.02 0.02 0 0 0.62 0.09 74 0

Garland 9.81 3.08 5.47 247.15 0 0.76 0.01 266 2,275

Hot Spring 3.13 0.24 0.76 0 0 0.30 3.67 8 1,326

Howard 3.87 0 1.14 0 0 0.84 0 6 0

Independence 3.83 1.57 1.60 8.56 0 0.78 20.23 37 0

Izard 2.19 0.09 0.09 0 0 0.56 0 3 0

Jackson 1.96 0.09 0.09 0 0 7.72 288.42 298 0

Johnson 2.14 0.61 0.53 0 0 0.64 0.31 4 0

Lawrence 1.27 1.05 0.18 0 0 0.41 278.48 281 0

Logan 2.75 0.37 0.36 0 0 1.07 0.37 5 0

Lonoke 4.35 0.11 1.07 0 0 71.66 295.75 373 0

Madison 1.62 0.37 0.36 0 0 1.30 0 4 0

Marion 1.07 0.11 0.10 0 0 0.46 0 2 4,718

Montgomery 1.12 0.03 0.05 0 0 0.42 0.04 2 0

Newton 0.63 0.01 0 0 0 0.33 0.06 1 0

Perry 0.94 0.05 0.04 0 0 0.37 2.98 4 0

Pike 0.92 0.23 0.22 0 0 0.50 0 2 185

Polk 3.22 0.36 0.36 0 0 0.69 0.23 5 0

Pope 5.66 34.99 2.53 967.12 0 0.92 1.22 1,012 8,948

Pulaski 47.70 7.20 7.28 0 0 0.71 23.37 86 0

Randolph 1.57 0.12 0.11 0 0 0.49 78.14 80 0

Saline 7.88 0.39 0.98 0 0.12 0.25 0.07 10 0

Scott 1.11 0.47 0.46 0 0 0.70 0 3 0

Searcy 1.06 0.08 0.08 0 0 0.54 0 2 0

Sebastian 17.88 6.93 6.93 0 0 0.52 0.11 32 0

Sevier 1.57 0.94 0.94 0 0 0.92 0 4 0

Sharp 1.14 0.21 0.21 0 0 0.46 0 2 0

Stone 0.91 0.19 0.18 0 0 0.52 0 2 0

Van Buren 1.92 0.02 0.02 0 0 0.56 0 3 0

Washington 13.96 5.36 5.33 0 0 2.60 0.12 27 0

White 6.36 1.04 1.03 0 0 3.13 102.46 114 0

Yell 3.55 2.99 0.31 0 0 1.02 1.83 10 0

Missouri

Barry 2.55 0.23 2.55 0 0 1.80 0.18 7 0

Barton 1.33 0.23 0.02 0 0 0.76 2.40 5 0

Benton 1.08 0.10 0 0 0 0.69 0.02 2 4,127

Bollinger 0.77 0.20 0 0 0 0.43 8.32 10 0

Butler 4.35 0.16 0 0 0 0.13 151.11 156 0

Camden 2.70 0.21 0.12 0 0 0.36 0.32 4 161

Carter 0.50 0.02 0 0 0 0.12 0.01 1 0

Cedar 1.03 0.20 0.19 0 0 0.66 0.01 2 353

Christian 3.03 0.09 0.59 0 0 0.88 0.12 5 0

Cole 7.35 0.92 0.18 0 0 0.58 0.25 9 0

Crawford 1.69 0.34 0 0 0 0.40 0.03 2 0

Dade 0.53 0.12 0 0 0 0.91 2.25 4 0

Dallas 1.03 0.06 0.01 0 0 0.91 0.07 2 0

Dent 0.96 0.16 0 0 0 0.48 0.12 2 0

(continued)

272
Table 5.2—Water use by State and county in 1995 in the Ozark-Ouachita Highlands (continued)

Offstream

withdrawal Offstream

Domestic thermo- withdrawal, Live- Crop

County and public Commercial Industrial electric mining stock irrigation Total Hydroelectric

 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Million gallons per day - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Missouri (continued)

Douglas 1.16 0.09 0 0 0 1.06 0.34 3 0

Franklin 7.69 0.37 0.04 957.51 0 0.94 0.01 967 0

Gasconade 1.64 0.29 0 0 0 0.52 0.10 3 0

Greene 24.09 3.96 4.68 141.72 0 1.30 0.15 176 0

Henry 1.64 0.10 0 354.9 0 0.89 0.47 358 0

Hickory 0.52 0.03 0 0 0 0.51 0.01 1 0

Howell 3.40 0.29 0.30 0 0 1.35 0.07 5 0

Iron 0.70 0.05 4.21 0 0 0.16 0.01 5 0

Jasper 11.30 1.73 7.75 1.68 0 0.93 2.52 26 0

Jefferson 10.95 0.79 3.22 819.8 0 0.27 0.18 835 0

Laclede 2.84 0.62 0.42 0 0 1.12 0.04 5 0

Lawrence 2.17 0.30 0.70 0 0 1.57 0.58 5 0

McDonald 1.97 0.34 1.13 0 0 1.37 0.48 5 0

Madison 0.91 0.16 0 0 0 0.26 0.02 1 0

Maries 0.56 1.94 0.06 0 0 0.67 0.06 3 0

Miller 1.52 0.29 0 0 0 1.20 0.15 3 8,382

Morgan 1.20 0.04 0.06 0 0 0.85 0.25 2 0

Newton 4.62 0.50 0.65 0 0 1.36 0.11 7 0

Oregon 2.89 0.23 0.02 0 0 0.78 0.09 4 0

Osage 0.82 0.16 0 32.47 0 1.28 0.05 35 0

Ozark 4.13 0.07 0 0 0 0.86 0.17 5 0

Phelps 3.12 0.25 0 0 0 0.41 0.12 4 0

Polk 2.39 0.20 0.01 0 0 1.55 0.19 4 0

Pulaski 6.05 0.91 0.16 0 0 0.33 0.03 7 0

Reynolds 0.42 0.02 0.22 0 2.89 0.15 0.01 4 0

Ripley 1.18 0.04 0 0 0 0.24 17.72 19 0

St. Clair 0.64 0.03 0 0 0 0.69 0.15 2 0

Ste. Genevieve 1.11 0.05 0.16 0 0 0.47 0 2 0

St. Francois 4.70 0.55 0 299.05 1.78 0.36 0.10 307 0

Shannon 0.56 0.08 0.05 0 0 0.27 0.01 1 0

Stone 2.24 0.87 0.12 0 0 0.58 0.02 4 0

Taney 8.28 0.55 0.27 0 0 0.37 0.04 10 3,623

Texas 1.83 0.07 0.57 0 0 1.43 1.47 5 0

Washington 1.49 0.42 0.06 0 6.63 0.27 0.01 9 0

Wayne 1.38 0.14 0.10 0 0 0.16 0.02 2 0

Webster 2.04 0.10 0 0 0 1.36 0.71 4 0

Wright 1.56 0.10 0.03 0 0 1.45 0.65 4 0

Oklahoma

Adair 2.10 2.12 0.52 0 0 2.46 2.44 10 0

Atoka 53.75 0.11 0 0 0 1.45 0.15 55 0

Cherokee 4.80 14.24 0.01 0 0 1.36 2.57 23 3,583

Delaware 1.30 1.32 0.36 0 0 2.87 0.02 6 0

Haskell 1.07 0.54 0 0 0 2.52 0.01 4 3,687

Latimer 0.89 0.23 0.03 0 0 0.89 0.17 2 0

Le Flore 7.89 1.38 0.77 0 0 2.75 1.45 14 15,393

McCurtain 5.32 1.81 1.27 0 0 2.83 0.07 11 605

Mayes 59.37 0.46 11.81 10.92 0 1.90 0 84 9,231

Muskogee 6.09 4.39 21.39 44.34 0 2.11 5.22 84 10,010

Ottawa 0.41 0.83 1.41 0 0 2.39 0 5 0

Pittsburg 3.77 2.73 1.07 0 0 2.71 0.11 10 0

Pushmataha 0.93 0.29 0 0 0 1.21 0.22 3 0

Sequoyah 9.14 1.50 0.31 0 0 1.33 1.80 14 1,000

Totals 519.70a 201.09a 135.75 4,212.72a 11.43 182.61 1,311.39a 6,575a 102,884

a Totals differ from table 5.1 as a result of rounding.

273
Table 5.3—Average annual water availability (from precipitation) compared with

withdrawals and consumptive use in the Highlands in 1995

River basin Watershed Water availability

Watershed name code (HUC) from precipitation Yield Withdrawal Consumptive use

 - - - - - - - Million gallons per day - - - - - - - % of yield Mgal/d % of yield

Osage River Basin

H.S. Truman Reservoir 10290105 2,395 703 4 0.6 2.5 0.4

Sac 10290106 3,904 1,150 18 1.5 7.7 0.7

Pomme de Terre 10290107 1,661 465 5 1.1 2.4 0.5

South Grand 10290108 3,844 1,249 366 29.3 9.2 0.7

Lake of the Ozarks 10290109 2,686 765 8 1.0 2.8 0.4

Niangua 10290110 2,053 629 5 0.8 2.4 0.4

Lower Osage 10290111 2,071 603 7 1.2 2.9 0.5

Gasconade River Basin

Upper Gasconade 10290201 3,548 1,268 12 0.9 4.9 0.4

Big Piney 10290202 1,506 527 5 0.9 1.9 0.4

Lower Gasconade 10290203 1,960 624 5 0.7 1.8 0.3

Meramec River Basin

Meramec 07140102 4,091 1,268 60 4.8 10.6 0.8

Bourbeuse 07140103 1,602 497 7 1.4 2.0 0.4

Big 07140104 1,806 519 12 2.3 2.4 0.5

Upper St. Francis River Basin

Upper St. Francis 08020202 3,826 1,164 10 0.9 3.5 0.3

Neosho-Illinois River Basin

Lake O’ the Cherokees 11070206 1,857 622 9 1.5 4.9 0.8

Spring 11070207 5,058 1,760 42 2.4 14.1 0.8

Elk 11070208 2,080 786 8 1.0 4.1 0.5

Lower Neosho 11070209 4,357 1,326 120 9.1 21.6 1.6

Illinois 11110103 3,424 1,350 381 28.2 14.4 1.1

Arkansas River Basin

Dirty-Greenleaf 11110102 1,527 416 68 16.3 20.5 4.9

Robert S. Kerr Reservoir 11110104 3,741 1,269 54 4.2 15.9 1.3

Poteau 11110105 4,025 1,476 18 1.2 7.0 0.5

Frog-Mulberry 11110201 2,753 1,056 23 2.2 6.9 0.7

Dardanelle Reservoir 11110202 4,047 1,381 1,017 73.6 8.5 0.6

Conway- Pt. Remove 11110203 2,585 811 29 3.5 9.9 1.2

Petit Jean 11110204 2,337 764 8 1.0 4.4 0.6

Cadron 11110205 1,774 593 18 3.0 2.1 0.3

Fourche La Fave 11110206 2,562 880 8 0.9 3.9 0.4

Lower Ark-Maumelle 11110207 2,628 908 110 12.2 46.9 5.2

Kiamichi-Little River Basin

Kiamichi 11140105 4,075 1,377 14 1.0 6.8 0.5

Upper Little 11140107 3,320 1,294 5 0.4 2.7 0.2

Mountain Fork 11140108 2,033 839 7 0.9 2.2 0.3

Lower Little 11140109 4,788 1,640 17 1.0 8.0 0.5

Ouachita-Saline River Basin

Ouachita Hdwaters 08040101 3,912 1,474 271 18.4 4.8 0.3

Upper Ouachita 08040102 4,372 1,377 46 3.3 11.3 0.8

Little Missouri 08040103 5,238 1,747 7 0.4 4.5 0.3

Upper Saline 08040203 4,264 1,519 9 0.6 2.2 0.1

Upper White River Basin

Beaver Reservoir 11010001 5,379 2,261 29 1.3 12.9 0.6

James 11010002 2,896 1,003 177 17.6 11.4 1.1

Bull Shoals Lake 11010003 5,328 1,615 19 1.2 5.9 0.4

Middle White 11010004 3,269 979 28 2.9 14.8 1.5

Buffalo 11010005 2,867 1,130 2 0.2 1.5 0.1

North Fork White 11010006 3,672 1,196 8 0.7 3.9 0.3

Little Red 11010014 4,149 1,420 46 3.2 27.8 2

Upper Black River Basin

Upper Black 11010007 4,098 1,339 174 13.0 121.0 9

Current 11010008 5,546 1,842 70 3.8 49.3 2.7

Lower Black 11010009 1,723 549 124 22.5 90.3 16.5

Spring 11010010 2,599 843 82 9.7 4.2 0.5

Eleven Point 11010011 2,601 872 5 0.5 2.2 0.3

Strawberry 11010012 1,666 508 8 1.6 5.8 1.1

Totala 159,502 53,652 3,583 6.7 635.3 1.2

HUC = hydrologic unit code; Mgal/d = million gallons per day.

a

 Totals differ from table 5.2 because watersheds included here omit some areas included in counties.

274
consumption in those three watersheds is low. Irrigation,

however, tends to consume 50 percent or more of

withdrawals, as demonstrated by the much higher

portion of water yield that is consumed in the Lower

Black watershed.

Table 5.3 reports average annual water use per

watershed. In dry years, watersheds yield much less

than normal. These yield differences are substantial.

For 1963—the driest year in the 1962 to 1988 study

period—water yield is estimated to have been about 8.4

billion gal/d or only 15 percent of the mean. Total 1995

withdrawals represent 43 percent of the 1963 water

supply. For 1980—the “next driest” year of the

record—water yield equaled about 23 billion gal/d or

about 42 percent of the mean. Total 1995 withdrawals

represented 16 percent of the 1980 available water

supply. The respective portions of available supply that

would have been consumed, given 1995 use levels, are 8

percent for 1963 weather conditions and 3 percent for

1980 conditions.

An important caution to this analysis at the watershed level is that the streamflow available in a given

watershed may receive flow from an upstream watershed; only the watersheds of the headwaters rely solely

on streamflow generated within their boundaries. Of the

four watersheds mentioned above that experience

relatively high withdrawal levels, the Lower Black is on

the Black River, which receives flow from several

headwater streams in upstream watersheds, and the

Dardanelle Reservoir takes its water from the Arkansas

River. The thermoelectric plants in the South Grand and

Illinois watersheds are in the headwaters and thus rely

on relatively limited water supplies. There are few, if

any, users between the intake and outflow points of the

thermoelectric plants in these watersheds, so effects of

such plants using a large quantity of water on other

users are likely to be minimal.

Future Patterns and Trends

Question 5.2: What future trends are likely for

water use and supply?

Adequate water supplies are critical for long-term

economic growth of any area or community. This

section calculates future water demands for the Assessment area. The Aquatic Team projects that overall

future use will remain a small fraction of the water

supply in most years to come.

 Key Findings

 1. Domestic and public withdrawals are projected to

increase from 143 gallons per day (gal/d) per

person in 1995 to 156 in 2040. Total domestic and

public withdrawals are thus projected to increase

from 538 million gal/d in 1995 to 675 in 2040.

 2. Total industrial and commercial withdrawals are

projected to drop from 339 million gal/d in 1995 to

214 in 2040.

 3. Total annual energy production at thermoelectric

plants in the Assessment area is projected to

increase from 75 billion kilowatt hours (kWh) in

1995 to 107 billion kWh in 2040.

 4. Total withdrawals for thermoelectric plants are

projected to drop from 4.2 billion gal/d in 1995 to

3.8 in 2040.

 5. Acres of crops irrigated are expected to increase

from 798 thousand in 1995 to 1,226 thousand in

2040. Total irrigation withdrawals are projected to

increase from 1.3 billion gal/d in 1995 to 2.0 billion

gal/d in 2040.

 6. Total withdrawals are projected to increase until

2020 and remain rather stable after that, staying

within 5 percent of 1995 withdrawals. Essentially

the increases in withdrawals for domestic and

public use and for irrigation are largely balanced by

the decreases in withdrawals for industrial, commercial, and thermoelectric uses.

275
Figure 5.3—Past and projected millions of gallons of water withdrawals per day (Mgal/d) for domestic and

public purposes in the Assessment area and population in millions (persons x 106

).

0

200

400

600

800

1,000

1985 1990 1995 2000 2010 2020 2030 2040

Mgal/d

0.0

1.0

2.0

3.0

4.0

5.0

Persons x 106

Population

Withdrawal

Withdrawals

Assumptions and Projections

The Aquatic Team projected domestic and public

withdrawals based on two assumptions. First, the team

assumed the number of persons per household (i.e., per

occupied housing unit) will drop at a rate of 1 percent

per decade. With this assumption, persons per household

will drop from 2.52 in 1995 to 2.41 in 2040. Second, the

team assumed withdrawals per household will increase

at a rate of 1 percent per decade. Based on this assumption, withdrawals per household increase from 359

gallons per day (gal/d) in 1995 to 376 in 2040.

Given these two assumptions, domestic and public

withdrawals are projected to increase from 143 gal/d

per person in 1995 to 156 in 2040. Total domestic and

public withdrawals are thus projected to increase from

538 million gal/d in 1995 to 675 in 2040 (fig. 5.3). Based

on Geological Survey estimates for 1995, about twothirds of those amounts are attributable to domestic use,

with the remainder allotted to public uses and losses.

The team projected industrial and commercial

withdrawals based on estimates of future populations

and income and assumptions about the rate of change in

withdrawals per dollar of income. The Bureau of

Economic Analysis projects per capita income in the

Assessment area, in 1990 dollars, to increase from

$15,005 in 1995 to $22,350 in 2040. The team assumed

that withdrawals per $1,000 of income, which has been

dropping steadily since 1960 due largely to enhanced

efficiency and recycling (Brown 1998), will continue

dropping at the somewhat lower rate than the previous

rate of 20 percent per decade. Given this assumption,

withdrawals per $1,000 of income drop from 6 gal in

1995 to 2.2 gal in 2040. Given these two assumptions,

total industrial and commercial withdrawals are projected to drop from 339 million gal/d in 1995 to 214 in

2040 (fig. 5.4).

The team projected withdrawals at thermoelectric

plants based on estimates of future populations and

assumptions about the rate of change in energy use per

person and in water use per kilowatt hour (kWh)

produced. The team assumed that per capita use of

energy generated at thermoelectric plants will increase

by 5 percent per decade. Given this assumption, the

team projected that the use of energy generated at

thermoelectric plants would increase from 19,917 kWh

per person per year in 1995 to 24,814 in 2040. This

trend, along with the expected population increase,

yields an increase in total annual energy production at

thermoelectric plants in the Assessment area from 75

billion kWh in 1995 to 107 billion in 2040 (fig. 5.5).

The team assumed that water withdrawals per kWh,

which have dropped consistently since 1960 with

increased recycling (Brown 1998), will continue decreasing at the somewhat lower rate than the previous

rate of 10 percent per decade. Given this rate of

decrease, water withdrawals per kWh produced at

thermoelectric plants in the Assessment area drop from

21 gal/kWh in 1995 to 13 in 2040. This trend, along with

the increase in energy production, causes total withdrawals for thermoelectric plants to drop from 4.2 in

1995 to 3.8 billion gal/d in 2040 (fig. 5.5).

276
Water withdrawals for crop irrigation were projected

based on assumptions about withdrawals per acre and

number of acres irrigated. The team assumed future

withdrawals per acre will remain constant at the 1985 to

1995 average of 22.2 in. They also assumed that future

numbers of acres irrigated will increase at a rate of 10

percent per decade. Acres irrigated are thus expected

to increase from 798 thousand in 1995 to 1,226 thousand

in 2040 (fig. 5.6). Total irrigation withdrawals are thus

projected to increase from 1.3 in 1995 to 2.0 billion gal/d

in 2040.

Figure 5.7 shows the future change in total withdrawals compared with the 1995 total withdrawal. Total

withdrawals are projected to increase until 2020 and

remain rather stable after that, staying within 5 percent

of the 1995 withdrawal. Essentially, the increases in

withdrawals for domestic and public use and for irrigation are largely balanced by the decreases in withdrawals for industrial, commercial, and thermoelectric uses.

These projections are based, by necessity, on educated guesses about future trends in population, income,

and the various factors that affect withdrawals in the

different water use categories. To give an idea of the

sensitivity of the projections to the assumptions, consider

the effect of an increase in energy use per person of 10

percent per decade, rather than the 5 percent increase

assumed above. In this case, 2040 total withdrawals

increase by 18 percent over 1995 withdrawals, rather

than the net increase of under 5 percent shown in fig.

5.7. Finally, it should be noted that these projections

ignore site specific changes that may place considerable

pressure on local water supplies.

Figure 5.4—Past and projected millions of gallons of water withdrawals per day (Mgal/d) for industrial and

commercial purposes and costs in billions of 1990 dollars (dollars x 109).

0

100

200

300

400

500

1985 1990 1995 2000 2010 2020 2030 2040

Mgal/d

0

20

40

60

80

100

120

Dollars x 109

Withdrawal

Total income

Figure 5.5—Past and projected millions of gallons of water withdrawals per day (Mgal/d) for thermoelectric

purposes and billions of kilowatt hours of energy production.

0

2,000

4,000

6,000

1985 1990 1995 2000 2010 2020 2030 2040

Mgal/d

0

40

80

120

Kilowatt hours x 109

Withdrawal

Kilowatt hours

277
Figure 5.7—Projected net change in millions of gallons of water per day (Mgal/d) withdrawn for all purposes

and percent increases compared to 1995 withdrawals (as a baseline).

0

50

100

150

200

250

300

1995 2000 2010 2020 2030 2040

Mgal/d

0

1

2

3

4

Percent change

While the overall picture is one of water abundance,

many communities and cities in the Highlands face

future shortages and are actively seeking new supplies

for domestic, industrial, and commercial use. Little

Rock, AR, for instance, which currently has two

reservoirs in the Ouachita Mountains, seeks a third

source to meet its long-term needs. Fort Smith, AR,

seeks to expand its existing water supply lake. Many

smaller communities (e.g., Benton and Marshall, AR)

are actively looking for new supplies. For a variety of

reasons, it is highly likely that communities will look to

Federal and State lands for as least some of their

freshwater needs.

Implications and Opportunities

In the typical year, water availability in the Assessment area as a whole is ample and easily supports

current and expected future water needs. With over 40

in. of average annual precipitation and relatively low

levels of crop irrigation in comparison to drier portions

of the United States, water use in the Assessment

region is relatively secure. However, as in most locations, severe droughts can cause short-term disruptions

in water use, especially in localized areas of unusually

heavy withdrawals. The individual users most likely to

be affected during droughts are those using the most

waterthermoelectric plants and farmers. Reservoir

storage within the region helps lower the severity of

such disruptions, as does temporarily increased reliance

on ground water. A comprehensive list of users with

potential shortages would be helpful for planning efforts.

Figure 5.6—Past and projected millions of gallons of water withdrawals per day (Mgal/d) for crop irrigation and

thousands of acres irrigated (acres x 103

).

0

500

1,000

1,500

2,000

2,500

3,000

1985 1990 1995 2000 2010 2020 2030 2040

Mgal/d

0

350

700

1,050

1,400

Acres x 103

Acres irrigated

Withdrawal

278
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297

Glossary of Terms

404 permit: a permit issued under section 404 of the CWA for

activities that require dredging and any filling of materials

into the waters of the United States.

adsorb: to bond molecularly.

aerate: to introduce air into a liquid.

algal blooms: noticeable growth of algae.

alkalinity: relative measure of basicity of a substance;

opposite of acidity; relative ability of a substance to donate

electron pairs to other substances or receive a hydrogen

atom from other substances. Any substance with a pH

higher than 7 is considered to be basic or have high

alkalinity.

alluvial: of, found in, or made of, alluvium.

alluvial fan: the fan-like pattern of a drainage or stream where it

issues from a gorge or a divide upon a plain or of a stream at

its confluence with a larger body of water.

alluvium: sediment gradually deposited by moving water on,

for example, flooded land, lakebeds, streambeds, alluvial

fans, or ocean floors.

ammonia: NH3

; gas that is very soluble in water; can be used

to create fertilizers and acid-neutralizing substances.

anomalously: unusually.

anticline: an upfold or arch of stratified rock in which the beds

or layers bend downward in opposite directions from the

crest.

antidegradation policy: requirement that State standards be

sufficient to maintain existing beneficial uses of navigable

waters, and prevent degradation. The U.S. Environmental

Protection Agency (EPA) requires that State water quality

standards include “a statewide antidegradation policy” to

ensure the maintenance of existing instream water uses and

the level of water quality necessary to protect the existing

uses.

aquifer: an underground geological formation or group of

formations that contain water, a source of ground water for

wells and springs.

areal: of, relating to, or involving area.

areal additivity: an increase in one factor accompanying an

increase in area.

atmospheric deposition: the addition of elements or substances found in the air to the surface of the Earth.

assessment: the act of estimating or determining the significance, importance, or value of something.

background source: a natural source, as opposed to a humancaused source; any recorded or observed activity in nature

that is other than that being tested for.

barite: a white, yellow, or colorless mineral consisting of native

barium sulfate BaSO4

.

basal: of or relating to the foundation.

baseline: scientifically gathered data on any subject that

provide a description of initial or “base” conditions.

basement: a compact, firm rock underlying less firmly consolidated earth materials.

basin: the entire tract of land drained by a river and its

tributaries.

benthic: of or pertaining to the bottom of a stream, lake, sea, or

ocean.

best management practices (BMP’s): methods, measures, and

practices selected by an agency to meet its need to control

nonpoint sources. BMP’s include but are not limited to

structural and nonstructural controls and operation and

maintenance procedures. BMP’s can be applied before,

during, and after activities to reduce or eliminate water

pollution caused by the activities.

biotic: of or pertaining to life; caused or produced by living

beings.

bituminous: having the quality of hydrocarbons that are

usually dark brown or black and occur naturally or are

obtained as residues.

buffering capacity: the ability of a solution to accept additions

of acid or alkali and not significantly change pH.

buffers: strips of vegetation separating a water body from land

that could generate nonpoint pollution. Such buffers vary in

width and length and can range from narrow vegetated filter

strips to extensive wetland or riparian areas. See nonpoint

source.

Cambrian Period: the first period of the Paleozoic Era that

began approximately 545 million years B.P. (before present)

and ended 495 million years B.P.

Carboniferous: pertaining to the portion of geologic time

between the Devonian and the Permian periods that began

approximately 360 million years B.P. and ended 286 million

299
years B.P., including the Mississipian and Pennsylvanian

periods.

carcinogen: a cancer-causing agent.

Carlson Trophic State Index: a formula to derive trophic status:

9.8 natural log [chlorophyll-A] + 30.6.

category 1: taxa for which USDI Fish and Wildlife Service

(USDI FWS) has sufficient information to support proposals

to list them as endangered or threatened species, but for

which proposed rules have not been issued.

category 2: formerly taxa for which USDI FWS had information

to indicate that proposing to list them as endangered or

threatened was possibly appropriate but for which persuasive data were not currently available.

Cenozoic Era: the fourth and current era of geologic time,

including the Quarternary and Tertiary periods, that began

approximately 65 million years B.P.

censored values: a set of figures in which greater than 5

percent of the total number of data values are flagged as

less than a certain detection limit or as not detected.

channelization: the modification of a channel by clearing,

excavation, realignment, lining, or other means to increase

its capacity for water flow.

cherty: substance resembling flint and consisting essentially of

cryptocrystalline quartz or fibrous chalcedony.

chlorophyll-A: a measure of algal standing crop and primary

productivity, pigment that allows photosynthesis to occur

in plants.

chroma: a color dimension that refers to the strength or purity

of the dominant soil color or the degree of saturation of the

dominant color.

clastic: fragmented.

colloid: a substance in a fine state of subdivision with particles

too small to be seen in a microscope that is dispersed in a

solid, liquid, or gaseous medium.

condition score: classification system for the water quality of

watersheds that uses the following categories as determined

by the EPA: better water quality, water quality with less

serious problems, or water quality with more serious

problems.

confining unit/confining system: relatively impervious layers

of rock that separate an aquifer from other aquifers.

confluence: portion of a stream where two or more streams

come together.

conglomerate: a rock consisting of pebbles and gravel

embedded in a loosely cementing material.

consumptive use: that part of withdrawn water that is evaporated, transpired, incorporated into products or crops,

consumed by humans or livestock, or otherwise removed

from the immediate water environment (also referred to as

water consumed).

contaminant: an unwholesome or undesirable element that

causes water to be polluted or unfit for use, e.g., bacteria

from raw sewage in a lake used for fishing and swimming.

contaminant source: the origin of the undesirable element that

causes water to be polluted, e.g., a sewage treatment plant

could be the primary source of bacteria that impairs a

stream. See impairment.

convectional: thermally or mechanically created upward or

downward movement of a limited part of the atmosphere.

convective precipitation events: atmospheric turbulence with

rainfall, snow, or icy precipitation caused by the collision of

warm and cool air masses that sets up convection-like

atmospheric circulations with warm air rising and cool air

falling sequentially.

conveyance: a channel or passage for conduction or transmission, as a pipe, canal, conduit, or ditch.

creel limits: limits on the number of fish that may be caught.

creel survey: a survey of anglers.

Cretaceous Period: the third and last period of the Mesozoic

Era that began approximately 144 million years B.P. and

ended 65 million years B.P.

currently stable species: a species or subspecies the status of

which is relatively unchanging throughout all or a significant portion of its range.

dendritic: a type of delta, alluvial, or wetland drainage in which

water flows through a branching, interlacing pattern of

channels.

detection limit: the lower limit of an analytical method.

Devonian Period: the fourth period of the Paleozoic Era that

began approximately 417 million years B.P. and ended 360

million years B.P.

digestion: the extraction of soluble materials.

dissolutioning: dissecting something into its component parts.

dolomite: a limestone or marble rich in magnesium carbonate.

drought: abnormal dryness, most often recognized during

seasons when substantial precipitation is expected but fails

300
to occur. Drought also is associated with higher than normal

surface temperatures and drier than normal atmospheric

moistures.

drusy: covered with minute crystals or containing cavities lined

with crystals.

easement: an interest in real property that conveys use or other

rights but not ownership.

ecological section: an area or region of land designated for

study purposes that has distinct geology, landforms, soils,

flora, and fauna that set it apart from surrounding geographic areas.

ecological-hydrologic unit: a combined unit of analysis created

by superimposing ecological sections on hydrologic units

to analyze animal species occurrence, richness, density, and

distribution.

ecology: the branch of biology that deals with relationships

between living organisms and their environment.

ecoregion: a region with distinctive, identifiable ecological

attributes.

ecosystem management: an ecological approach to natural

resource management to assure productive, healthy

ecosystems by blending social, economic, physical, and

biological needs and values.

ecotone: a transitional zone between two adjacent communities,

containing species characteristic of both as well as other

species occurring only within the zone.

effluent: that which flows out or forth; the outflow of a sewer,

septic tank, or industrial facility.

Element Occurrence Record (EOR): documentation for the

occurrence of a species in a specific location, as recorded

by a State natural heritage agency or The Nature Conservancy.

embayment: bay or formation resembling a bay.

endangered species: a species or subspecies in danger of

extinction throughout all or a significant portion of its range,

as rated and listed by the USDI FWS.

endemic (endemism): species restricted to a particular geographic area; for aquatic species, usually limited to one or a

few small streams, a single drainage, or an ecological

section.

Environmental Quality Incentives Program (EQIP): USDA

NRCS cost-share program for riparian restoration.

epeirogenic uplift: relief-producing deformation of the Earth’s

crust.

escarpment: a steep slope or cliff formed by erosion or faulting.

estuarine: of or relating to an estuary, which is an inlet or arm

of the sea, especially the lower portion or wide mouth of a

river where salty tide meets freshwater current.

eutrophic: the second highest trophic state. Eutrophic lakes

have accumulated high levels of nitrogen, phosphorous,

and other nutrients, and are thus often very green due to

large algal blooms.

eutrophication: a cumulative process by which lakes receive

(1) agricultural runoff (nutrients such as nitrogen and

phosphorus), (2) rural and urban sewage and industrial

effluents, and (3) natural nutrients (such as leaves and fallen

trees), supporting increased algal and other aquatic plant

growth and gradually filling lakes with sediment and

decaying organic matter; process of elevation of trophic

state.

evapotranspiration: total water loss from the soil, including that

by direct evaporation and that by transpiration from the

surfaces of plants.

extirpation: elimination of a species in part of its range, e.g.,

from a State, river basin, or watershed.

extraordinary resource waters: water bodies and their

watersheds that are characterized by scenic beauty, scientific values, broad scope recreation potential, and intangible

social values.

extratropical: any climatic zone outside of the tropics.

extreme precipitation event: an event occurring within 24

hours that results in 2 or more inches of moisture.

extreme temperature: an occurrence of maximum or minimum

temperature greater than 20 oF above or below normal for a

particular day.

fault: a fracture in the Earth’s crust accompanied by a displacement of one side of the fracture with respect to the other

and in a direction parallel to the fracture.

Federal status: category assigned to plant and animal species

by the USDI FWS: threatened, endangered, potentially

endangered, or candidate. Candidate species are those for

which the USDI FWS has sufficient information to initiate

listing under the Endangered Species Act.

fertilizer: chemically prepared substance that provides

nutrients to soil.

fissile: capable of being split, cleft, or divided.

floodplain: a lowland area adjoining a watercourse.

301
fold: a bending into an arch or a trough of rock produced by

forces after the depositing or consolidation of the rock

freshwater: water that contains less than 1,000 milligrams per

liter (mg/L) of dissolved solids; generally, more than 500 mg/

L of dissolved solids is undesirable for drinking and many

industrial uses.

fungicides: chemicals used to kill unwanted fungi.

game fish: any fish species that may be legally caught for

recreational purposes.

geochemical: of, relating to, or using the methods of the

science that concerns itself with the chemical composition

of and actual or possible changes of substances within the

Earth’s crust.

geomorphology: a science that deals with the land and submarine relief features of the Earth’s surface and seeks a genetic

interpretation of them; physiography.

glauconitic: resembling glauconite, a mineral of dull green iron

potassium silicate.

global ranks: ranks assigned to plant and animal species by

The Nature Conservancy and State heritage programs based

on the number of occurrences of each species and denoted

by “G” and a number (1-5) or a letter code: G?, G_Q_,

G_T_, G1, G2, G3, G4, and G5. Two G, T, or S rankings

together (e.g., G2G3) indicate the range in uncertainty about

the status of the taxa. Also see State ranks and individual

G and S rankings.

G?: unranked, or rank uncertain. See global ranks and State

ranks.

G_Q_: questionable taxonomic assignment.

G_T_: rank of a subspecies or variety (e.g., G5T1 denotes a

critically imperiled subspecies of a globally secure species).

G1: extremely rare and critically imperiled species, as

determined by the network of State natural heritage

programs, The Nature Conservancy, and other experts

with five or fewer occurrences, very few remaining

individuals and/or especially vulnerable to extinction.

G2: very rare and imperiled, with 6 to 20 occurrences, few

remaining individuals, and/or extremely vulnerable to

extinction.

G3: characterized by at least one of the following: (1) very

rare and local throughout its range, (2) very rare and

found locally (sometimes abundantly within that area) in

a restricted range, or (3) vulnerable to extinction; usually

fewer than 100 occurrences are known.

G4: apparently secure globally, although possibly quite rare

in parts of its range, especially at the periphery; usually

100 to 1,000 occurrences.

G5: demonstrably secure globally, though possibly quite

rare in parts of its range, especially at the periphery;

usually at least 1,000 occurrences.

ground water: generally, all subsurface water (as distinct from

surface water); specifically, that part of the subsurface water

in the saturated zone (a zone in which all voids are filled

with water) where the water is under pressure greater than

atmospheric.

ground water divides: places where the flow of ground water

changes direction markedly; structures that separate one

aquifer from another; see confining unit/confining system.

growing season: the portion of the year when soil temperatures

19.7 inches below the soil surface are higher than biologic

zero (5 oC). For ease of determination, this period can be

approximated by the number of frost-free days.

herbaceous growth: plant growth having the nature of an herb

or herbs, as distinguished from woody plants.

herbicides: chemicals used to kill unwanted plant pests.

herptiles: amphibians and reptiles.

hydraulic: of, involving, moved, or operated by a fluid,

especially water under pressure.

hydraulic conductivities: the ability of water to move through

strata of different permeablities while under the hydraulic

gradient.

hydric soil: a soil that is saturated, flooded, or ponded long

enough during the growing season to develop anaerobic

(oxygen-lacking) conditions that favor the growth and

regeneration of hydrophytic vegetation.

hydroelectric power water use: the use of water in the generation of electricity at plants where the turbine generators are

driven by falling water. Hydroelectric water use is classified

as an instream use in this report.

hydrogeology: water and terrain interactions.

hydrologic unit: a geographic area representing part or all of a

surface drainage basin or distinct hydrologic feature as

delineated by the Office of Water Data Coordination on

State hydrologic unit maps; each hydrologic unit is identified by an eight-digit number; in this report, hydrologic

units are also referred to as watersheds.

hydrologic unit code (HUC): an eight-digit code used to

catalog watersheds.

302
hydrology: the science dealing with the study of water on the

surface of the land, in soil and underlying rocks, and in the

atmosphere.

hypereutrophic: the highest trophic state. Hypereutrophic

lakes have received exceptionally large amounts of nitrogen,

phosphorus, and other nutrients and consequently have

very heavy growths of algae and other plants.

hypolimnetic releases: discharges from reservoirs of deeper,

colder water with lower oxygen.

igneous: rocks formed by solidification from a molten or

partially molten state.

impaired or threatened waters: water body that is not supporting or may not support potentially beneficial uses. After a

State pollution control agency monitors and evaluates

streams and lakes to see if their beneficial uses are being

protected, the State designates contaminated waters as

impaired or threatened.

impairment: adverse change that results in a water body not

fully supporting its designated beneficial uses (e.g., as a

domestic water supply, swimming area, or fishery). Impairment may result from a point source (e.g., untreated sewage

flowing out of a pipe directly into a water body or one of its

tributaries) or a nonpoint source (e.g., erosion moving from

a field into a stream).

impounded: confined and stored as by a reservoir or dam.

impoundments: human-engineered and dammed lakes, ponds,

and reservoirs.

industrial water use: water used in processing, such as

smelting, refining petroleum, or slurry pipeline operations.

inorganics: being or composed of matter other than plant or

animal; minerals.

instream: within the aquatic environment of a stream, river, or

channel.

instream use: water that is used, but not withdrawn, from a

ground or surface water source for such purposes as

hydroelectric power generation, navigation water quality

improvement, fish propagation, and recreation. Sometimes

called nonwithdrawal use or in-channel use.

Interior Highlands: that region of the South-Central United

States that contains the Ozarks Plateaus Province and

Ouachita Province; more or less equivalent to the OzarkOuachita Highlands.

introduced species: species that has been intentionally or

accidentally released in a locale by humans.

irrigation water use: artificial application of water on lands to

assist in the growing of crops and pastures or to maintain

vegetative growth in recreational lands such as parks and

golf courses.

Jurassic Period: the second period of the Mesozoic Era that

began approximately 213 million years B.P. and ended 144

million years B.P.

karst: an area of irregular limestone in which erosion has

produced fissures, sinkholes, underground streams, and

caverns.

kilowatt hour (kWh): unit of work or energy equal to that

expended in 1 hour at a steady level of 1 kilowatt.

kriging: statistically spacing instrument readings or other data

over distance.

lake retention time: period of time until the volume of lake

water is replaced entirely by new water.

land use: particular function to which a region is being put,

e.g., agricultural or forested.

leachate: any element or compound that is separated from

strata, landfills, or other sources through percolating

chemical processes.

legislatively designated waters: streams and lakes that

Congress and/or State legislatures have designated for

special recognition and protection.

lithology: study of the outermost solid layers of the Earth or

description (e.g., structure, composition, color) of rock

found in a geological area.

loess: an unstratified loamy soil material distributed by wind.

management indicator species (MIS): species whose population changes are believed to indicate the effects of management activities.

meander: a turn or bend in a stream.

mesotrophic: the second lowest trophic state. Mesotrophic

lakes have received somewhat more nutrients and have

greater aquatic plant growth than oligotrophic lakes.

Mesozoic Era: the third era of geologic time, including the

Cretaceous, Jurassic, and Triassic periods, that began

approximately 248 million years B.P. and ended 65 million

years B.P. This era is characterized by the predominance of

reptilian life forms.

million gallons per day (Mgal/d): a rate of flow of water.

Mississippian Period: the fifth period of the Paleozoic Era that

began approximately 360 million years B.P. and ended 320

million years B.P.

303
mussel: an aquatic bivalve mollusk that is especially abundant

in waters of the Central United States and has a shell with a

lustrous lining.

National Priorities List (NPL): a published list of hazardous

waste sites in the United States that are eligible for extensive, long-term cleanup under the Superfund program.

National Resources Inventory (NRI): a statistically based,

nationwide inventory of land uses and natural resource

conditions and trends (e.g., erosion potential) on rural, nonFederal lands.

native species: species that is within its known historical range

and for which there is no evidence of humans having

artificially introduced it.

nitrate: salts of nitric acid formed from reaction of nitric acid

with metals, their oxides, and hydroxides.

nitrite: family of compounds containing the NO2

-

 ion; usually

bonded to other compounds through one of the oxygen

atoms to form substances such as nitric acid.

nitrogen fixation: act of converting nitrogen as it is found in air

into a form usable by plants and animals, e.g., the making of

nitrogen fertilizer.

nonpoint source: any nonidentifiable conveyance from which

contaminants (pollutants) enter and impair a stream, e.g.,

erosion moving soil from a field into a lake. See point

source, buffers.

nonpoint source pollution: a diffuse source of pollution not

regulated as a point source. May include atmospheric

deposition, agricultural runoff, and sediment from landdisturbing activities.

novaculite: a very hard, fine-grained siliceous rock that

outcrops in the Ouachita Mountains (AR, OK).

nutrient: chemical substances or compounds taken in by living

things that are necessary to sustain growth and life, e.g.,

nitrogen and phosphorus.

nutrient loading: an effect of urbanization, concentrated animal

production (e.g., poultry and hog farming) and intensive,

high-input agriculture whereby runoff and residues containing treated and untreated human and animal waste, nitrogen

fertilizers, and other nutrient-rich elements load soils and

water bodies, creating “nutrient sinks” (areas containing

high nutrient levels) that increase problems such as algal

blooms in water bodies and impaired drinking water supplies.

offstream use: water withdrawn or diverted from a ground or

surface water source for public water supply, industry,

irrigation, livestock, thermoelectric power generation, and

other uses. Sometimes called off-channel use or withdrawal.

oligotrophic: the lowest trophic state. Oligotrophic lakes

received low levels of nitrogen, phosphorus, and other

nutrients and thus have little algae or other aquatic plant

growth.

Ordovician Period: the second period of the Paleozoic Era that

began approximately 495 million years B.P. and ended 445

million years B.P.

organic: of or pertaining to living things; compounds containing carbon that also have either carbon-carbon or carbonhydrogen bonds.

orogeny: mountain building era.

orographic: of or relating to mountains.

orthophosphate: PO4

3-; form of phosphorus most readily used

by aquatic plants because of its solubility in water.

oxidation (or oxidize): chemical process by which oxygen is

added to a compound or electrons are removed; the process

of rusting; combustion.

Paleozoic Era: the second era of geologic time (Cambrian

Period through Permian Period) that began approximately

545 million years B.P. and ended 248 million years B.P.

parent material: substance from which soils are derived, e.g.,

limestone, sandstone, shale.

pearl blanks: a round piece of shell inserted in commercial

pearl oysters to stimulate pearl formation.

Pennsylvanian Period: the sixth period of the Paleozoic Era that

began approximately 320 million years B.P. and ended 286

million years B.P.

per capita use: the average amount of water used per person

during a standard time period, e.g. per day or per year.

percolation: the slow passage of a liquid through a filtering

medium.

perennial stream: streams that flow throughout the year.

permeability: the rate at which liquids pass through soil.

Permian Period: the seventh and last period of the Paleozoic

Era that began approximately 286 million years B.P. and

ended 248 million years B.P.

pH: the negative logarithm of hydrogen ion activity. Substances with lower pH’s are more likely to donate hydrogen

ions to other substances. Substances with higher pH’s are

more likely to accept hydrogen ions from other substances.

A pH of 7 is considered neutral. Anything with a pH lower

than 7 is considered acidic, anything higher is considered

alkaline. A difference of 1 pH unit indicates a tenfold change

in hydrogen ion activity.

304
phosphorus: an active nonmetal that forms compounds used in

foods, explosives, matches, agricultural chemicals, soaps,

and some special metal alloys; nutrient essential to plants

and animals.

physiography: the study of the surface features of the land.

physiographic area: a geographic area defined by its surface

features.

Pleistocene Age (Epoch): a division of geologic time that began

approximately 1,800,000 years B.P. and ended 10,000 years

B.P.

point source: any single, identifiable conveyance from which

pollutants enter the waters of the United States, e.g.,

wastewater discharge pipes, stormwater drains, mine pits,

ditches, channels, tunnels, industrial facilities, smokestacks,

and conduits. See nonpoint source.

point source pollution: contamination or impairment from a

known specific point of origination, such as sewer outfalls

or pipes.

pollutant: something that causes something else to be unclean,

contaminated, or impaired.

pollution: the act of impairing or the state of being impaired,

e.g., mill wastes can cause pollution in streams.

population density: number of persons per unit area, i.e., people

per square mile.

porosity: the state of being capable of absorbing moisture.

potential erosion: erosion that is determined by a mathematical

formula designed to estimate the amount of actual erosion

that is possible from an area of land characterized by a

predominant use of the land.

Pre-Cambrian Era: the first era of geologic time that began

when Earth was formed and ended approximately 545 million

years B.P.

precipitable water: water that may fall as rain or frozen precipitation.

precipitate: (1) the deposition of condensed material, such as

rain; (2) the condensed and solidified result of chemical

processes.

precipitation: a deposit on the Earth of rain, mist, hail, sleet, or

snow; also, the amount of water deposited.

precipitation gradient: the rate of change in the amount of rain,

snow or icy precipitation over a prescribed distance.

primary mineralization: mineralization that occurs while a

stratum is being deposited.

province: in the context used in the report, a geographic area

having particular geologic and landform characteristics.

P-value: probability.

Quarternary Period: the current period of geologic time that

began approximately 1.6 million years B.P.

rare species: any native species that exists in a State in small

numbers.

relief: differences in height, collectively, of landforms in a

given area (e.g., from valley floor to mountain top).

reservoir: an artificial lake in which water is impounded for a

variety of uses.

residuum: rock and soil material that is weathered in place.

resource extraction: the removal of natural resources from the

Earth for use by human beings.

rhyolitic: of or relating to a very acid volcanic rock.

riparian zone/riparian area: in this report, the area of land on

either side of streams, channels, rivers, and other water

bodies. These areas are normally distinctly different from

the surrounding lands because of unique soil and vegetation characteristics (e.g., wetter soil than adjacent soil

conditions where aquatic vegetative communities thrive),

and they generally provide corridors for wildlife use.

road class: classification of roads using the following designations: Class 1 is Federal interstate highways, Class 2 is State

highways, and Class 3 is county roads.

rootwads: large clumps or networks of exposed roots.

runoff: water that drains from the land into stream or river

channels after precipitation.

secchi depth: a visibility measurement to determine the

underwater depth at which equal black and white quarters of

a disk cannot be distinguished from each other by the

human eye.

secondary mineralization: mineralization that occurs after a

stratum is initially deposited.

section 303(d): part of the Clean Water Act that requires

designated use and water quality criteria components be

contained in water quality standards.

sediment: material created by activities (mechanical and

chemical) and deposited by water, wind, or glaciers.

sensitive species: a term used for species of special concern by

some States.

305
shale: a fissile rock that has been formed by the consolidation of

clay, mud, or silt, has a finely stratified or laminated structure

parallel to the bedding, and is composed of minerals that

have been essentially unaltered since deposition.

siltation: the process whereby waterborne soil constituents are

deposited in succeeding layers by the force of gravity on

flooded land, lakebeds, streambeds, alluvial fans, and ocean

floors.

Silurian Period: the third period of the Paleozoic Era that

began approximately 445 million years B.P. and ended 417

million years B.P.

silviculture: the theory and practice of controlling forest

establishment, growth, composition, and structure.

soil series: groups of soils with similar characteristics.

soil tilth: the texture and friability (crumbling quality) of soil,

often apparent after plowing or shovel testing.

special concern: a term used by some States for certain native

species determined to require monitoring and/or special

management.

species density: total number of native species per square mile.

species richness: the total number of native species within a

particular region.

State 305(b) reports: water quality reports submitted by each

State to the EPA; these reports show the type and cause of

effects on aquatic resources in each State.

State ranks: ranks assigned to the species by State heritage

programs based on number of known occurrences of each

species in the State. The ranks (S1 through S5) are the same

as global ranks, which are described in detail under this

term.

S1: Critically Imperiled—Critically imperiled species in a

State because of extreme rarity or because of some

factor(s) making it especially vulnerable to extirpation

from the State. Typically, there are five or fewer occurrences of a critically imperiled species or there are very

few remaining individuals or acres in which they occur.

S2: Imperiled—Imperiled species in a State because of rarity

or because of some factor(s) making it very vulnerable to

extirpation from the State. Typically, there are 6 to 20

occurrences of an imperiled species or there are few

remaining individuals or acres in which they occur.

S3: Vulnerable—Vulnerable species in a State because it is

rare or uncommon. Typically, 21 to 100 occurrences of the

species are found only in a restricted range (even if

abundant at some locations); or because of other factors

making the species vulnerable to extirpation.

SH: Historical—Element occurred historically in the State

(with an expectation that it may be rediscovered),

perhaps having not been verified in the past 20 years,

and is suspected to be present still. Naturally, an element

would be SH without such a 20-year delay if the only

known occurrences in a State were destroyed or if it had

been extensively and unsuccessfully looked for. The SH

rank should be reserved for elements for which some

effort has been made to relocate occurrences, rather than

simply ranking all elements not known from verified

extant occurrences with this rank.

SX: Extirpated—Element is believed to be extirpated from

the State (or province or other subnational unit).

stewardship: careful and responsible management of resources.

STOrage and RETrieval system (STORET): EPA’s oldest and

largest computerized environmental repository for water

quality and biological monitoring data. For more information, see the Web site at <http://www.epa.gov/OWOW/

STORET/>.

strata: layers of rock.

stratigraphic: pertaining to strata, or layers, as in a description

of layers of rock types.

stratigraphy: the arrangement of strata.

stream reach: a segment of a stream.

streamside management area (SMA) or streamside

management zone (SMZ): a designated area that consists of

the stream itself and an adjacent area of varying width

where management practices that might affect water quality,

fish, or other aquatic resources are modified. An SMA is an

area that acts as a filter and absorption zone for sediments,

maintains shade, protects riparian and terrestrial riparian

habitat; protects channels and stream banks, and promotes

floodplain stability.

stream type: a combination of three landscape-scale attributes

that determine the classification of a moving body of water:

(1) hydrologic unit, (2) ecological section, and (3) stream

size.

stressor: pressure or change brought upon an ecosystem by

pollution sources such as contaminants and toxins.

subsidence: something that is deposited, such as sediment.

Superfund: a congressionally mandated fund administered by

the EPA to clean up designated toxic landfills and other U.S.

306
sites that contain levels of toxins and contaminants that are

deemed a threat to public and environmental health.

Superfund site: a hazardous waste site that poses health and

environmental threats, particularly through contaminated

drinking, surface, or ground water.

surface water: an open body of water such as a stream or lake.

suspended sediment: matter that would usually sink to the

bottom of a liquid that has been mixed with, but not dissolved in a liquid.

suspended solid: material in a suspending medium that, when

removed, would retain the properties of the solid state of

matter.

syncline: a trough of layered rock in which the beds dip toward

each other from either side.

taxa: two or more taxonomic groups or entities.

taxon: a taxonomic group or entity, the name applied to a

taxonomic group in a formal system of nomenclature.

taxonomy: classification of organisms into categories according

to their natural relationships.

tectonic: relating to rock structures formed by forces that

deform the Earth’s crust.

temperature gradient: the rate of change of temperature over a

set distance.

temporal: having to do with time. Temporal distribution of data

includes sampling time periods and frequency.

Tertiary Period: the first period of the Cenozoic Era that began

approximately 65 million years B.P. and ended 1.6 million

years B.P.

thermoelectric power water use: water used to generate

thermoelectric power.

threatened species: a species or subspecies that is likely to

become endangered throughout all or a significant portion

of its range and listed as such by the USDI FWS.

topography: the configuration of a surface (usually the Earth’s

surface) including its relief and the position of its natural

and artificial features.

total maximum daily load (TMDL): the sum of (1) a waste load

allocation (WLA), or that portion of a surface water’s

loading capacity that is allocated to an existing or future

point source discharge; (2) a load allocation (LA), or that

portion of the surface water’s loading capacity that is due to

either existing or future nonpoint source pollution or to

natural background sources; and (3) a margin of safety

(MS), or that portion of a surface water’s loading capacity

that is allocated to uncertainty.

total potential erosion (TPE): the sum of potential erosion

estimates for cropland, forest, pasture, rangeland, and

“other” land.

toxics: pollutants that reach poisonous levels in the air, water

or soil; examples include heavy metals, pesticides, herbicides, fertilizers, and other nutrients.

transmissivity: the ability of an aquifer to transmit water.

Triassic Period: the first period of the Mesozoic Era that began

approximately 248 million years B.P. and ended 213 million

years B.P.

tributary: a stream feeding a larger stream, river, or lake.

trophic status: the degree of eutrophication of a lake. It

includes the designations of oligotrophic, mesotrophic,

eutrophic, and hypereutrophic. Trophic status provides

insight into the lake’s productivity and its future.

turbid: murky; opaque or clouded with suspended matter.

turbidity: a measure of water clarity.

ubiquitous: existing everywhere.

unconformities: breaks in the depositional sequence of rock

from dislocations, erosion, and nondeposition.

unionacean bivalves: aquatic lifeforms commonly referred to as

mussels, clams, naiads, or unionids.

Universal Soil Loss Equation (USLE): an equation developed

to predict soil losses due to runoff from specific field areas

in specified agricultural cropping and management systems.

The equation consists of a rainfall and runoff factor, soil

erodibility factor, slope-length factor, slope-steepness factor,

cover and management factor, and support practice factor.

vulnerability: capability of being injured. A watershed with low

vulnerability can easily tolerate increases of pollutants while

a watershed with a high vulnerability cannot easily absorb

increases in pollutants.

vulnerability indicator: a condition of aquatic system quality

that, when present, points to a threat to the aquatic system;

examples of vulnerability indicators are fish and wildlife

consumption advisories and contaminated sediments.

vulnerability scores: classification system of water quality that

categorizes watersheds as either having high or low

vulnerability to stressors as determined by the EPA.

Water Data Storage and Retrieval System (WATSTORE):

USDI’s Geological Survey data base, a part of the National

307
Water Information System (NWIS). Files are maintained for

the storage of (1) surface water, quality of water, and ground

water data measured daily or more frequently, (2) annual

peak values and peaks above a base flow for streamflow

stations, (3) chemical analyses for surface and ground water

sites, (4) geologic and inventory data for ground water sites,

and (5) water use summary data. For more information,

consult the following on the Internet: <http://

water.usgs.gov/public/nawdex/wats/intro.html>.

water quality: information about the chemical, physical and/or

biological characteristics, overall usefulness, and varieties

of streams, lakes, and ground water.

water quality standard: a standard that defines the goals for a

water body or portion of a water body, by designating the

beneficial use or uses to be made of the water and by

setting criteria necessary to protect the uses. Water quality

standards should provide for the protection and propagation of fish, shellfish, and wildlife and for recreation in and

on the water, and should take into consideration the use and

value of public water supplies. Such standards establish

water quality goals for a specific water body and serve as

the regulatory basis for the establishment of water qualitybased treatment controls and strategies beyond the

technology-based treatment required by sections 301(b) and

306 of the CWA.

water use: (1) in a restrictive sense, water that is actually used

for a specific purpose, such as for domestic use, irrigation,

or industrial processing. In this report, the quantity of water

use for a specific category is the combination of selfsupplied withdrawals and public supply deliveries; (2) more

broadly, water use pertains to human interaction with and

influence on the hydrologic cycle, and includes elements

such as water withdrawal, delivery, consumptive use,

wastewater release, reclaimed wastewater, return flow, and

instream use. See offstream use and instream use.

water year: a 12-month period from October 1st through

September 30th; a water year is designated by the calendar

year in which it ends (e.g., the 1998 water year was from

October 1, 1997, through September 30, 1998).

watershed: the area of land above a given point on a stream

that contributes water to the volume of a body of surface

water; also referred to as hydrologic unit or drainage basin.

wetlands: those areas that are inundated or saturated by

surface or ground water at a frequency and duration

sufficient to support, and that under normal circumstances

do support, a prevalence of vegetation typically adapted for

life in saturated soil conditions (U.S. ACE 1987). Wetlands

generally include (1) swamps, marshes, bogs, and similar

areas, and (2) lands that are transitional between terrestrial

and aquatic systems where the water table is usually at or

near the surface of the land and is covered by shallow water.

For purposes of this classification, wetlands must have one

or more of the following attributes: (1) at least periodically,

the land predominantly supports hydrophytes (plants

dependent on saturated soils or a water medium); (2) the

substrate is predominantly undrained hydric soil; and (3)

the substrate is nonsoil and is saturated with water or

covered by shallow water at some time during the growing

season of each year.

Wetlands Reserve Program (WRP): USDA NRCS cost-share

program for restoring wetlands. For more information, see

the following Web site: <http://www.nrcs.usda.gov/

NRCSProg.html#Anchor-Wetlands>.

wind shear: an increase in wind speed with a shift in the height

and wind direction from southerly to southwesterly and

westerly.

withdrawal: water removed from the ground or diverted from a

surface water source for use. See offstream use.

zoogeography: geographic distribution of animals.

308
Glossary of Abbreviations and Acronyms

AALC: acute aquatic life criterion or criteria

AFS: American Fisheries Society

AR DPCE: Arkansas Department of Pollution Control and

Ecology

AR GC: Arkansas Geological Commission

AR GFC: Arkansas Game and Fish Commission

AR HTD: Arkansas Highway and Transportation Department

AR M-AWPT: Arkansas Multi-Agency Wetlands Planning

Team

BASINS: Better Assessment Science Integrating Point and

Nonpoint Sources

BMP’s: best management practices

B.P.: before the present time

CERCLA: Comprehensive Environmental Response, Compensation, and Liability Act of 1980, P.L. 96-510 Stat. 2767, 42

U.S.C. 9601-9675

CERCLIS: Comprehensive Environmental Response, Compensation, and Liability Information System; the data base is

maintained by the EPA

CFR: Code of Federal Regulations

CTA: Conservation Technical Assistance program

CWA: Clean Water Act

DLG: Digital Line Graph (USDI GS data)

EOR’s: Element Occurrence Records

EPA: U.S. Environmental Protection Agency

EQIP: Environmental Quality Incentives Program

ESA: Endangered Species Act

EWP: Emergency Watershed Protection

FL DEP: Florida Department of Environmental Protection

FR: Federal Register

ft: foot or feet

ft/d: feet per day

ft2

/d: square feet per day

ft3/s: cubic feet per second

FWPCA: Federal Water Pollution Control Act

gal/d: gallon or gallons per day

gal/min: gallon or gallons per minute

GIRAS: Geographic Information Retrieval and Analysis System

(USDI GS data)

GIS: Geographic Information System

HUC: hydrologic unit code

in.: inch or inches

IWI: Index of Watershed Indicators

KS DHE: Kansas Department of Health and Environment

kWh: kilowatt hour

lb: pound or pounds

MCL: maximum contaminant level

Mgal/d: million gallons per day

mg/L: milligrams per liter

mi: mile or miles

mi/h: miles per hour

MIS: management indicator species

MO DC: Missouri Department of Conservation

MO DNR: Missouri Department of Natural Resources

MS: margin of safety

MSHA: Mine Safety and Health Administration

μg/L: micrograms per liter

NAWQA: National Water-Quality Assessment program

NCASI: National Council of the Paper Industry on Air and

Stream Improvement

NPDES: National Pollutant Discharge Elimination System

NPL: National Priorities List

NRI: National Resources Inventory

NSP: Nonpoint Source Pollution

NWP’s: nationwide permits

OK DEQ: Oklahoma Department of Environmental Quality

OK DM: Oklahoma Department of Mines

309
OK DWC: Oklahoma Department of Wildlife Conservation

OK WRB: Oklahoma Water Resources Board

ORW: Outstanding Resource Water

OSHA: Occupational Safety and Health Administration

PCS: Permits Compliance System

pH: hydrogen ion concentration; relative measure of acidity or

alkalinity.

P.L.: Public Law (Federal)

P-value: probability

RF1: River File version 1 (EPA data base)

RF2: River File version 2 (EPA data base)

RF3: River File version 3 (EPA data base)

SCORP: the Statewide Comprehensive Outdoor Recreation

Plan in Arkansas

SMA: Streamside Management Area (also called SMZ)

SMZ: Streamside Management Zone (also called SMA)

STATSGO: State Soil Geographic data base

STORET: EPA’s data STOrage and RETrieval system

STP: sewage treatment plant

TMDL: Total Maximum Daily Load

TPE: total potential erosion

TRI: Toxics Release Inventory

TRIS: Toxic Release Inventory System

U.S. ACE: U.S. Army Corps of Engineers

U.S. BOR: U.S. Bureau of Outdoor Recreation

U.S.C.: United States Code

U.S. DOA: U.S. Department of the Army

U.S. EPA: U.S. Environmental Protection Agency

USDA: U.S. Department of Agriculture

USDA FS: U.S. Department of Agriculture, Forest Service

USDA NRCS: U.S. Department of Agriculture, Natural

Resources Conservation Service

USDC: U.S. Department of Commerce

USDC BEC: U.S. Department of Commerce, Bureau of Economic Analysis

USDI: U.S. Department of the Interior

USDI FWS: U.S. Department of the Interior, Fish and Wildlife

Service

USDI GS: U.S. Department of the Interior, Geological Survey

USDI GS BRD: U.S. Department of the Interior, Geological

Survey, Biological Resources Division

USDI NPS: U.S. Department of the Interior, National Park

Service

USDL Mine Safety and Health Administration: U.S. Department of Labor, Mine Safety and Health Administration

WATSTORE: Water Data Storage and Retrieval System

WLA: waste load allocation

WRP: Wetlands Reserve Program

310
List of Tables

Page

Table 1.1—Major river basins of the aquatic study area and their drainage areas, land uses, principal tributaries,

and major reservoirs, by principle physiographic area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Table 1.2—Drainage area and national forest lands of aquatic study area watersheds . . . . . . . . . . . . . . . . . . . . . 8

Table 1.3—Number and acres of lakes and ponds in the aquatic study area, by major river basins . . . . . . . . . . . . 19

Table 2.1—Federal and State agency sources and major water quality data collection purpose, type, and

accessibility for the Assessment area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Table 2.2—Summary by Federal and State agency of the number of sites, collection methods, and frequency of

surface water quality samples utilized in this report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Table 2.3—Surface water sites for nutrient and suspended solids data (sites mapped in fig. 2.1) . . . . . . . . . . . . . 63

Table 2.4—Nutrients and suspended solids measured at surface water quality sites in the aquatic study area,

by physiographic area and land use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Table 2.5—Sampling stations for nutrient and suspended solids examined for long-term changes in water

quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

Table 2.6—Surface area and trophic status of selected Arkansas lakes in the aquatic study area . . . . . . . . . . . . . 88

Table 2.7—Trophic status as determined by chlorophyll-A, total phosphorous, and the Carlson Trophic State

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

Table 2.8—Trophic status of selected Missouri lakes in the aquatic study area . . . . . . . . . . . . . . . . . . . . . . . . . . 90

Table 2.9—Surface area and trophic status of selected Oklahoma lakes in the aquatic study area . . . . . . . . . . . . 91

Table 2.10—Ground water quality data for major aquifers in the Assessment area . . . . . . . . . . . . . . . . . . . . . . . . 95

Table 2.11—Native, endemic, and introduced fishes of the aquatic study area . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

Table 2.12—Native, endemic, and introduced fish species of the aquatic study area, by basin and ecologicalhydrologic unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

Table 2.13—Native and introduced mussels of the Ozark-Ouachita Highlands and their conservation status . . . 119

Table 2.14—Average mussel species richness and density for sections within the Assessment area . . . . . . . . . . 121

Table 2.15—Freshwater mussel species richness and density, conservation-rank values, and total endemics

within the Assessment area by ecological-hydrologic unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

Table 2.16—Mussel species richness and density, conservation-rank richness and density, index of relative

importance, and overall rank for watersheds within the aquatic study area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

Table 2.17—Crayfishes of the Ozark-Ouachita Highlands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134

Table 2.18—Crayfish species richness, species density, and number of endemic species by watershed . . . . . . . . 135

Table 2.19—Stoneflies (Plecoptera), caddisflies (Tricoptera), and combined species richness and density

within watersheds of the aquatic study area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143

Table 2.20—Aquatic insects by order, family, and species found within the Assessment area . . . . . . . . . . . . . . . 147

Table 2.21—Endangered, threatened, and other species of special concern in the aquatic study area . . . . . . . . . 156

311
Page

Table 2.22—Number of aquatic species with Federal status or special concern status that are found in the

aquatic study area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

Table 2.23—Commercial mussel species in the aquatic study area, by State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

Table 2.24—Game and commercial fish species of the Assessment area, by State . . . . . . . . . . . . . . . . . . . . . . . . . 166

Table 2.25—Additional game fish species stocked in study area water bodies, by State and river basin . . . . . . . 169

Table 2.26—Fish species in the aquatic study area ranked as endangered, threatened, or of special concern

by the American Fisheries Society . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172

Table 2.27—Mussel species in the aquatic study area ranked as endangered, threatened, of special concern,

or currently stable by the American Fisheries Society . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173

Table 2.28—Crayfish species in the aquatic study area ranked by the American Fisheries Society as

endangered, threatened, of special concern, or currently stable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175

Table 2.29—Stream type diversity and numbers of native and endemic fish species in the aquatic study area

watersheds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178

Table 2.30—Acres in riparian areas and predominant land uses within riparian zones of Assessment area

watersheds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182

Table 2.31—Acres in riparian areas and the predominant land uses within those riparian areas, by national

forest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184

Table 2.32—Some important wetlands in Assessment area counties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187

Table 2.33—Permits denied, general and individual permits issued, and permits withdrawn under Section 404

of the Clean Water Act in Assessment area counties (1988–1996) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188

Table 3.1—A summary of statutes related to water quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192

Table 4.1—Miles of Assessment area streams classified as Outstanding Resource Waters (ORW’s) (by State

and national forest), portion of these ORW’s in the States and national forests, and portion of the Assessment

area occupied by each national forest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204

Table 4.2—Stream miles within the Assessment area identified as impaired in State 305(b) reports by primary

and (where known) secondary source(s) of contamination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206

Table 4.3—Sources (primary or secondary) and types of contaminants and their relative contributions to stream

impairment in the Assessment area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208

Table 4.4—Stream miles within national forests affected by contaminants, as identified in State 305(b) reports

showing primary and (where listed) secondary sources and associated contaminants . . . . . . . . . . . . . . . . . . . . . 208

Table 4.5—Superfund (NPL) and CERCLIS sites within the aquatic study area, by watershed . . . . . . . . . . . . . . . 214

Table 4.6—NPDES sites and site density within the aquatic study area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217

Table 4.7—Number of drinking water sites, sources, volume produced, and population served, by watershed . . 221

Table 4.8—Number and density of toxic release sites and discharge areas in the aquatic study area . . . . . . . . . . 224

Table 4.9—Miles of roads in riparian areas of the aquatic study area watersheds, by road class . . . . . . . . . . . . . 228

Table 4.10—Miles of roads within riparian areas on national forests in the Assessment area, by road class . . . . 229

Table 4.11—Potential erosion rates in the aquatic study area, by land use category and year (1992, 1987, 1982) . 231

Table 4.12—Estimated annual cropland and pasture applications of selected pesticides in the Assessment area,

pesticide type, and use, 1987 through 1991 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

312
313

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Table 4.13—Major sources of pesticide data for the aquatic study area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241

Table 4.14—Numbers of pesticide sampling sites and samples collected in physiographic areas of the

Ozark-Ouachita Highlands, by monitoring agency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242

Table 4.15—Surface water sampling sites for which pesticide data are available . . . . . . . . . . . . . . . . . . . . . . . . . . 244

Table 4.16—Statistical summary of detected pesticide concentrations from surface water sampling sites in

the Ozark Plateaus (water years 1970 through 1990), the Arkansas Valley, and Ouachita Mountains

(1975 through 1995). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246

Table 4.17—Comparison of maximum detected pesticide concentrations in surface water samples by

physiographic area, with selected quality criteria and standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248

Table 4.18—Pesticides detected in ground water and their range of concentrations in the Ozark Plateaus . . . . . . 250

Table 4.19—Estimated animal populations and nutrient contributions from animal wastes by physiographic

area in 1992 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254

Table 4.20—Estimated nitrogen and phosphorus fertilizer use by major river basin, 1965 and 1985 . . . . . . . . . . . 256

Table 4.21—Human population and percent change in population from 1980 to 1990, by watershed . . . . . . . . . . 259

Table 4.22—Number of mining-related operations for selected mineral commodity groups in the Assessment

area in 1996 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261

Table 4.23—Mining-related effects on streams in the Assessment area by State, stream, and watershed . . . . . . . 263

Table 4.24—Stream miles impaired by historic, gravel, sediment, and other mining activities by State . . . . . . . . . 264

Table 5.1—Fresh water uses in the Ozark-Ouachita Highlands, 1985–1995 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271

Table 5.2—Water use by State and county in 1995 in the Ozark-Ouachita Highlands . . . . . . . . . . . . . . . . . . . . . . 272

Table 5.3—Average annual water availability (from precipitation) compared with withdrawals and consumptive

use in the Highlands in 1995 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274
List of Figures

Page

Figure 1.1—Physiographic subdivisions of the aquatic study area (adapted from Fenneman 1938). . . . . . . . . . . . xxiv

Figure 1.2—Major river basins and watersheds (with hydrologic unit codes) of the aquatic study area. . . . . . . . 5

Figure 1.3—Watersheds of the Upper White River Basin with major tributaries and reservoirs. . . . . . . . . . . . . . . 9

Figure 1.4—Watersheds of the Neosho-Illinois River Basin with major tributaries and reservoirs. . . . . . . . . . . . . 10

Figure 1.5—Watersheds of the Osage River Basin with major tributaries and reservoirs. . . . . . . . . . . . . . . . . . . . 11

Figure 1.6—Watersheds of the Gasconade River Basin with major tributaries. . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Figure 1.7—Watersheds of the Meramec River Basin with major tributaries. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Figure 1.8—Upper St. Francis River Basin with major tributaries and reservoir. . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Figure 1.9—Watersheds of the Upper Black River Basin with major tributaries. . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Figure 1.10—Watersheds of the Arkansas River Basin with major tributaries and reservoirs. . . . . . . . . . . . . . . . . 16

Figure 1.11—Watersheds of the Ouachita-Saline River Basin with major tributaries and reservoirs. . . . . . . . . . . . 17

Figure 1.12—Watersheds of the Kiamichi-Little River Basin with major tributaries and reservoirs. . . . . . . . . . . . . 18

Figure 1.13—Directions of the flow of ground water in the Ozark Plateaus Province (modified from Adamski

and others 1995). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Figure 1.14—Locations of hydrogeologic units in the Ozark Plateaus (modified from Adamski and others 1995). 21

Figure 1.15—Average daily maximum temperatures (°F) during January, April, July, and October for the region

within and surrounding the Ozark-Ouachita Highlands Assessment area.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Figure 1.16—Average daily minimum temperatures (°F) during January, April, July, and October for the region

within and surrounding the Ozark-Ouachita Highlands Assessment area.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Figure 1.17—Total number of occurrences where daily maximum temperatures were 20 °F above normal and

20 °F below normal in the region within and surrounding the Ozark-Ouachita Highlands Assessment area from

1950 through 1993. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Figure 1.18—Total number of occurrences where daily minimum temperatures were 20 °F above normal and

20 °F below normal in the region within and surrounding the Ozark-Ouachita Highlands Assessment area from

1950 through 1993. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Figure 1.19—Average yearly precipitation (in inches) in the region within and surrounding the Ozark-Ouachita

Highlands Assessment area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Figure 1.20—Average monthly precipitation (in inches) during January, April, July, and October in the region

within and surrounding the Ozark-Ouachita Highlands Assessment area.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Figure 1.21—Total number of occurrences where daily precipitation was 2 inches or more in the region within

and surrounding the Ozark-Ouachita Highlands Assessment area from 1950 through 1993. . . . . . . . . . . . . . . . . . 36

Figure 1.22—Total number of occurrences where daily precipitation was 2 inches or more in January, April, July,

and October in the region within and surrounding the Ozark-Ouachita Highlands Assessment area from 1950

through 1993. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Figure 1.23—Total number of reported tornadoes in Arkansas and Missouri from 1950 through 1995. . . . . . . . . . 39

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Figure 1.24—Total number of reported tornadoes each month in Arkansas and Missouri from 1950 through

1995. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Figure 1.25—Mean annual runoff (in inches) in the aquatic study area from 1951 through 1980 (Gebert and

others 1987). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Figure 1.26—Stratigraphic column of the Assessment area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Figure 1.27—Geologic age of major formations underlying the Ozark-Ouachita Highlands and portions of some

surrounding physiographic provinces.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Figure 1.28—Land conditions in the Assessment area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Figure 2.1—Locations of surface water sampling sites in the aquatic study area. . . . . . . . . . . . . . . . . . . . . . . . . . 62

Figure 2.2—Statistical distribution of nitrite plus nitrate concentrations at surface water sites for water years

1980 through 1990 (Ozark Plateaus) and 1985 through 1995 (Arkansas Valley and Ouachita Mountains) (modified

from Davis and others 1995). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Figure 2.3—Statistical distribution of ammonia concentrations at surface water sites for water years 1980

through 1990 (Ozark Plateaus) and 1985 through 1995 (Arkansas Valley and Ouachita Mountains) (modified

from Davis and others 1995). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Figure 2.4—Statistical distribution of total ammonia plus organic nitrogen concentrations at surface water sites

for water years 1980 through 1990 (Ozark Plateaus) and 1985 through 1995 (Arkansas Valley and Ouachita

Mountains) (modified from Davis and others 1995). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Figure 2.5—Statistical distribution of total nitrogen concentrations at surface water sites for water years 1980

through 1990 (Ozark Plateaus) and 1985 through 1995 (Arkansas Valley and Ouachita Mountains) (modified

from Davis and others 1995). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

Figure 2.6—Statistical distribution of total phosphorus concentrations at surface water sites for water years

1980 through 1990 (Ozark Plateaus) and 1985 through 1995 (Arkansas Valley and Ouachita Mountains) (modified

from Davis and others 1995). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Figure 2.7—Statistical distribution of orthophosphate concentrations at surface water sites for water years

1980 through 1990 (Ozark Plateaus) and 1985 through 1995 (Arkansas Valley and Ouachita Mountains) (modified

from Davis and others 1995). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Figure 2.8—Statistical distribution of suspended solids concentrations at surface water sites for water years

1980 through 1990 (Ozark Plateaus) and 1985 through 1995 (Arkansas Valley and Ouachita Mountains) (modified

from Davis and others 1995). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Figure 2.9—Concentrations of nitrite plus nitrate for water years 1970 through 1990 (Ozark Plateaus) and 1975

through 1995 (Arkansas Valley and Ouachita Mountains) at selected surface water sites. . . . . . . . . . . . . . . . . . . 79

Figure 2.10—Concentrations of ammonia for water years 1970 through 1990 (Ozark Plateaus) and 1975 through

1995 (Arkansas Valley and Ouachita Mountains) at selected surface water sites. . . . . . . . . . . . . . . . . . . . . . . . . . 81

Figure 2.11—Concentrations of total ammonia plus organic nitrogen for water years 1970 through 1990 (Ozark

Plateaus) and 1975 through 1995 (Arkansas Valley and Ouachita Mountains) at selected surface water sites. . . . 82

Figure 2.12—Concentrations of total phosphorus for water years 1970 through 1990 (Ozark Plateaus) and 1975

through 1995 (Arkansas Valley and Ouachita Mountains) at selected surface water sites. . . . . . . . . . . . . . . . . . . 83

Figure 2.13—Concentrations of orthophosphate for water years 1970 through 1990 (Ozark Plateaus) and 1975

through 1995 (Arkansas Valley and Ouachita Mountains) at selected surface water sites. . . . . . . . . . . . . . . . . . . 84

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Figure 2.14—Concentrations of suspended solids for water years 1970 through 1990 (Ozark Plateaus) and 1975

through 1995 (Arkansas Valley and Ouachita Mountains) at selected surface water sites. . . . . . . . . . . . . . . . . . . 85

Figure 2.15—Location of ground water sampling sites in the aquatic study area. . . . . . . . . . . . . . . . . . . . . . . . . . 94

Figure 2.16—Concentrations of nitrite plus nitrate concentrations in wells and springs in the three major aquifers

of the Assessment area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

Figure 2.17—River basins, watersheds, and ecological sections of the aquatic study area (showing derivation of

ecological-hydrologic units). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

Figure 2.18—Levels of native fish species richness by ecological-hydrologic unit. . . . . . . . . . . . . . . . . . . . . . . . 109

Figure 2.19—Levels of native fish density by ecological-hydrologic unit.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

Figure 2.20—Levels of endemic fish species richness by ecological-hydrologic unit. . . . . . . . . . . . . . . . . . . . . . . 114

Figure 2.21—Levels of native freshwater mussel species richness by ecological-hydrologic unit. . . . . . . . . . . . . 121

Figure 2.22—Levels of freshwater mussel conservation-rank species richness by ecological-hydrologic unit. . . 122

Figure 2.23—Levels of freshwater mussel species density by ecological-hydrologic unit. . . . . . . . . . . . . . . . . . . 126

Figure 2.24—Levels of freshwater mussel species richness by watershed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

Figure 2.25—Levels of freshwater mussel conservation-rank species richness by watershed. . . . . . . . . . . . . . . . 129

Figure 2.26—Levels of freshwater mussel species density by watershed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

Figure 2.27—Levels of crayfish species richness by watershed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

Figure 2.28—Levels of crayfish species density by watershed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

Figure 2.29—Levels of endemic crayfish species richness by watershed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

Figure 2.30—Levels of stonefly and caddisfly species richness (combined) by watershed. . . . . . . . . . . . . . . . . . 144

Figure 2.31—Levels of stonefly and caddisfly species density (combined) by watershed. . . . . . . . . . . . . . . . . . . 145

Figure 2.32—Levels of endemic stonefly and caddisfly species richness (combined) by watershed. . . . . . . . . . . 152

Figure 2.33—Number of endangered and threatened aquatic species by watershed. . . . . . . . . . . . . . . . . . . . . . . 159

Figure 2.34—Levels of endangered, threatened, and special concern aquatic species by watershed. . . . . . . . . . . 161

Figure 2.35—Stream type diversity by watershed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179

Figure 2.36—Percent of forested riparian areas by Assessment area watershed. . . . . . . . . . . . . . . . . . . . . . . . . . . 183

Figure 2.37—Areas of hydric soils in and adjacent to the Ozark-Ouachita Highlands. . . . . . . . . . . . . . . . . . . . . . 186

Figure 4.1—Locations of Outstanding Resource Waters (ORW’s) within the Assessment area. . . . . . . . . . . . . . . 205

Figure 4.2—Locations of impaired streams within the Assessment area as identified in the Oklahoma, Missouri,

and Arkansas 305(b) reports. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207

Figure 4.3—Water quality (WQ) categories of Assessment area watersheds as determined by the Index of

Watershed Indicators (IWI). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

Figure 4.4—Locations of Superfund sites in the Assessment area as reported by Oklahoma, Arkansas, Kansas,

and Missouri to the EPA (U.S. EPA 1996a, b). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213

Figure 4.5—Facilities discharging effluents into surface waters of the Assessment area that have National

Pollutant Discharge Elimination System (NPDES) permits (U.S. EPA 1996a, b). . . . . . . . . . . . . . . . . . . . . . . . . . . . 218

316
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Figure 4.6—Density of National Pollutant Discharge Elimination System (NPDES) permits in the Assessment

area (U.S. EPA 1996a, b). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219

Figure 4.7—Locations of public drinking water sources in the Assessment area (U.S. EPA 1996a, b). . . . . . . . . . 220

Figure 4.8—Toxics Release Inventory (TRI) sites in the Assessment area by watershed, 1992 (U.S. EPA

1996a, b). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223

Figure 4.9—Average potential erosion in the aquatic study area by watershed for all land use categories in

1992 (USDA NRCS 1997). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235

Figure 4.10—Major pesticide use in the Assessment area by county, 1987 through 1991 (calculated from data

in Gianessi and Puffer 1991; 1992a, b). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238

Figure 4.11—Locations of surface water pesticide sampling sites and sites where pesticides were detected in

the Assessment area (Bell and others 1996). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243

Figure 4.12—Locations of ground water pesticide sampling sites and sites where pesticides were detected in

the Ozark Plateaus Province (Adamski 1997a). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251

Figure 4.13—Human population changes from 1980 to 1990 by watershed (U.S. EPA 1997a). . . . . . . . . . . . . . . . . 258

Figure 5.1—Total water withdrawals in million gallons per day (Mgal/d) in Arkansas and Missouri from 1950 to

1995, including 1985 to 1995 withdrawals in the Assessment area.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270

Figure 5.2—Categories of water withdrawals in the Assessment area for 1995. . . . . . . . . . . . . . . . . . . . . . . . . . . . 271

Figure 5.3—Past and projected millions of gallons of water withdrawals per day (Mgal/d) for domestic and

public purposes in the Assessment area and population in millions (persons x 106

). . . . . . . . . . . . . . . . . . . . . . . . 276

Figure 5.4—Past and projected millions of gallons of water withdrawals per day (Mgal/d) for industrial and

commercial purposes and costs in billions of 1990 dollars (dollars x 109

). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277

Figure 5.5—Past and projected millions of gallons of water withdrawals per day (Mgal/d) for thermoelectric

purposes and billions of kilowatt hours of energy production. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277

Figure 5.6—Past and projected millions of gallons of water withdrawals per day (Mgal/d) for crop irrigation

and thousands of acres irrigated (acres x 103

). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278

Figure 5.7—Projected net change in millions of gallons of water per day (Mgal/d) withdrawn for all purposes

and percent increases compared to 1995 withdrawals (as a baseline). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278

317

U.S. Department of Agriculture, Forest Service. 1999. Ozark-Ouachita Highlands

Assessment: aquatic conditions. Report 3 of 5. Gen. Tech. Rep. SRS-33. Asheville,

NC: U.S. Department of Agriculture, Forest Service, Southern Research Station.

317 p.

This publication provides citizens, private and public organizations, scientists, and

others with information about the aquatic conditions in or near national forests in the

Ozark-Ouachita Highlands: the Mark Twain in Missouri, the Ouachita in Arkansas and

Oklahoma, and the Ozark-St. Francis National Forests in Arkansas. This report includes

water quality analyses, status of aquatic species, aquatic and riparian habitat conditions, water laws and policies, effects of human activities, and water resource usage

and trends in the Ozark-Ouachita Highlands Assessment area.

Keywords: Climate, crayfishes, fishes, geology, invertebrates, lakes, land use, mussels,

nonpoint sources, point sources, rivers, soils, threatened and endangered species,

water.

The Forest Service, U.S. Department of Agriculture, provides leadership in the

management, protection, and use of the Nation’s forests and rangelands. The Agency

takes an ecological approach to the implementation of multiple-use management,

providing sustained yields of renewable resources such as water, forage, wildlife,

wood, and recreation. The Forest Service has embraced ecosystem management as its operating

philosophy and is committed to the preservation of wilderness, biodiversity, and landscape beauty

as well as the protection of the basic resources of soil, water, and air quality.

The Forest Service is responsible for the 191.8-million-acre National Forest System, with its 155

national forests and 20 grasslands in 44 States, Puerto Rico, and the Virgin Islands. In addition, the

Agency works with State land management organizations to help private landowners apply good

natural resource management practices on their lands. The International Program of the Forest

Service enables the Agency to share its technical expertise and managerial skills with other nations.

The Research and Development Program of the Forest Service conducts extensive research to

enhance and protect productivity on all of America’s forests and rangelands, with special attention

to long-term natural resource issues of national and international scope.

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

activities on the basis of race, color, national origin, gender, religion, age, disability, political beliefs,

sexual orientation, and marital or familial status. (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 USDA, Director, Office of Civil Rights, Room 326-W,

Whitten Building, 14th and Independence Avenue, SW, Washington, DC 20250, or call 202-720-5964

(voice or TDD). USDA is an equal employment opportunity provider and employer.
This report is one of five that documents the results of the Ozark-Ouachita Highlands

Assessment. Three of the remaining reports examine Air Quality, Social and Economic

Conditions, and Terrestrial Vegetation and Wildlife, respectively, and the fourth provides an

overall summary.

Air Quality

REPORT

2

OF 5

Highlands Assessment

Ozark-Ouachita

Summary Report

REPORT

1

OF 5

Ozark-Ouachita

Highlands Assessment

Terrestrial Vegetation and Wildlife

REPORT

5

OF 5

Highlands Assessment

United States

Department of Ozark-Ouachita Agriculture

Forest Service

General Technical

Report SRS-35

REPORT

4

OF 5

Ozark-Ouachita

Highlands Assessment

United States

Department of

Agriculture

Forest Service

General Technical

Report SRS-34 Social and Economic Conditions

United States

Department of

Agriculture

Forest Service

General Technical

Report SRS-31 General Technical

Report SRS-32

United States

Department of

Agriculture

Forest Service