Clean Water Rule Response to Comments – Topic 8: Tributaries

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Clean Water Rule Comment Compendium

Topic 8: Tributaries

The Response to Comments Document, together with the preamble to the final Clean Water 

Rule, presents the responses of the Environmental Protection Agency (EPA) and the Department 

of the Army (collectively “the agencies”) to the more than one million public comments received 

on the proposed rule (79 FR 22188 (Apr. 21, 2014)). The agencies have addressed all significant 

issues raised in the public comments.

As a result of changes made to the preamble and final rule prior to signature, and due to the volume 

of comments received, some responses in the Response to Comments Document may not reflect the 

language in the preamble and final rule in every respect. Where the response is in conflict with the 

preamble or the final rule, the language in the final preamble and rule controls and should be used for 

purposes of understanding the scope, requirements, and basis of the final rule. In addition, due to the 

large number of comments that addressed similar issues, as well as the volume of the comments 

received, the Response to Comments Document does not always cross-reference each response 

to the commenter(s) who raised the particular issue involved. The responses presented in this 

document are intended to augment the responses to comments that appear in the preamble to the 

final rule or to address comments not discussed in that preamble. Although portions of the 

preamble to the final rule are paraphrased in this document where useful to add clarity to 

responses, the preamble itself remains the definitive statement of the rationale for the revisions 

adopted in the final rule. In many instances, particular responses presented in the Response to 

Comments Document include cross references to responses on related issues that are located 

either in the preamble to the Clean Water Rule, the Technical Support Document, or elsewhere 

in the Response to Comments Document. All issues on which the agencies are taking final action 

in the Clean Water Rule are addressed in the Clean Water Rule rulemaking record.

Accordingly, the Response to Comments Document, together with the preamble to the Clean 

Water Rule and the information contained in the Technical Support Document, the Science 

Report, and the rest of the administrative record should be considered collectively as the 

agencies’ response to all of the significant comments submitted on the proposed rule. The 

Response to Comments Document incorporates directly or by reference the significant public 

comments addressed in the preamble to the Clean Water Rule as well as other significant public 

comments that were submitted on the proposed rule.

This compendium, as part of the Response to Comments Document, provides a compendium of 

the technical comments about tributaries submitted by commenters. Comments have been 

copied into this document “as is” with no editing or summarizing. Footnotes in regular font are 

taken directly from the comments.
Clean Water Rule Response to Comments – Topic 8: Tributaries

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TOPIC 8. TRIBUTARIES.............................................................................................................. 19

8.1. DEFINITION ........................................................................................................................ 19

AGENCY SUMMARY RESPONSE.................................................................................... 19

SPECIFIC COMMENTS ................................................................................................... 21

National Association of State Foresters (Doc. #14636)........................................ 21

Tennessee Valley Association (Doc. #17470)...................................................... 23

Bullhead City, Arizona (Doc. #4185)................................................................... 25

Pennsylvania Fish and Boat Commission (Doc. #4826) ...................................... 25

Quapaw Tribe of Oklahoma (the O-Gah-Pah) (Doc. #7980) ............................... 26

Pennsylvania Department of Environmental Protection, Office of Water 

Management (Doc. #7985) ................................................................................... 27

Barona Band of Mission Indians (Doc. #10966) .................................................. 27

Department of Justice, State of Montana (Doc. #13625)...................................... 30

Illinois Farm Bureau (Doc. #14070)..................................................................... 30

North Carolina Department of Agriculture and Consumer Services (Doc. #14747)

............................................................................................................................... 31

San Carlos Apache Tribe (Doc. #15067).............................................................. 31

Florida Department of Environmental Protection (Doc. #15080) ........................ 32

Tennessee Department of Environment and Conservation (Doc. #15135) .......... 32

Wisconsin Department of Natural Resource (Doc. #15141) ................................ 33

California State Water Resources Control Board (Doc. #15213)......................... 34

Sealaska Corporation (Doc. #15356).................................................................... 36

North Dakota Office of the Governor et al. (Doc. #15365).................................. 39

Ohio Department of Natural Resources et al. (Doc. #15421)............................... 40

Wyoming Department of Environmental Quality (Doc. #16393) ........................ 40

Indiana Department of Environmental Management (Doc. #16440) ................... 41

Office of the Governor, State of Utah (Doc. #16534) .......................................... 41

State of South Dakota (Doc. #16925)................................................................... 42

Allen Boone Humphries Robinson LLP (Doc. #19614)....................................... 43

Franconia Township, Pennsylvania (Doc. #8661)................................................ 43

City of Escondido (Doc. #11116)......................................................................... 44

Clark County Regional Flood Control District, Nevada (Doc. #11726) .............. 44

Uintah County, Utah (Doc. #12720)..................................................................... 45

National Association of Flood & Stormwater Management Agencies (Doc. 

#13613) ................................................................................................................. 45

Board of County Commissioners, Otero County, New Mexico (Doc. #14321)... 45

Board of County Commissioners, Delta County, Colorado (Doc. #14405) ......... 46

Board of Supervisors, Cochise County, Arizona (Doc. #14541).......................... 47

Waters of the United States Coalition (Doc. #14589) .......................................... 47

Board of Supervisors, San Joaquin County, California (Doc. #15017.1)............. 48

Flood Control and Water Conservation District, Alameda County, California 

(Doc. #15074) ....................................................................................................... 48

National Association of Counties (Doc. #15081)................................................. 48

Painesville Township, Ohio (Doc. #15183).......................................................... 49

Department of Public Works, County of San Diego, California (Doc. #17920).. 49

Butte County Administration, County of Butte, California (Doc. #19593).......... 50
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Board of Supervisors, Sutter County, California (Doc. #19657).......................... 51

North Dakota Water Resource Districts Association (Doc. #5596) ..................... 52

Utah Association of Counties (Doc. #14756)....................................................... 52

Washington State Water Resources Association (Doc. #16543).......................... 52

League of Oregon Cities (Doc. #16546)............................................................... 54

Michigan Association of Conservation Districts (Doc. #16583).......................... 54

Wyoming Water Development Commission (Doc. #17059)................................ 54

Indiana Cast Metals Association (Doc. #14895.1) ............................................... 55

Golf Course Superintendents Association of America et al. (Doc. #14902)........ 55

Institute of Scrap Recycling Industries, Inc. (Doc. #15041)................................. 55

National Association of Manufacturers (Doc. #15410)........................................ 56

Texas Chemical Council (Doc. #15433)............................................................... 57

GBMC & Associates (Doc. #15770) .................................................................... 57

Federal Water Quality Coalition (Doc. #15822.1)................................................ 58

Water Advocacy Coalition (Doc. #17921.1) ........................................................ 60

American Society of Civil Engineers (Doc. #19572)........................................... 65

Minnkota Power Cooperative, Inc. (Doc. #19607)............................................... 65

Kerr Environmental Services Corps. (Doc. #7937.1)........................................... 66

Kansas Independent Oil & Gas Association (Doc. #12249)................................. 66

Pennsylvania Coal Alliance (Doc. #13074).......................................................... 67

O'Neil LLP (Doc. #14651).................................................................................... 67

West Valley Planned Communities (Doc. #18906).............................................. 68

CEMEX (Doc. #19470) ........................................................................................ 68

National Association of Home Builders (Doc. #19540)....................................... 69

Home Builders Association of Tennessee (Doc. #19581).................................... 71

Freeport-McMoRan Inc. (Doc. #14135, #14135.1, and #14135.2)...................... 73

National Stone, Sand and Gravel Association (Doc. #14412).............................. 78

Wyoming Mining Association (Doc. #14460)...................................................... 79

The Mosaic Company (Doc. #14640)................................................................... 80

Continental Resources, Inc. (Doc. #14655).......................................................... 81

Sinclair Oil Corporation (Doc. #15142) ............................................................... 82

Halliburton Energy Services, Inc. (Doc. #15509)................................................. 83

Illinois Coal Association (Doc. #15517) .............................................................. 84

Dominion Resources Services, Inc. (Doc. #16338).............................................. 85

Montana Wool Growers Association (Doc. #5843.1) .......................................... 86

Alameda County Cattlewomen (Doc. #8674)....................................................... 86

National Sorghum Producers (Doc. #10847)........................................................ 87

Nebraska Cattlemen (Doc. #13018)...................................................................... 87

Missouri Agribusiness Association (Doc. #13025) .............................................. 88

North American Meat Association and American Meat Institute (Doc. #13071) 88

Illinois Corn Growers Association (Doc. #13996) ............................................... 89

Indiana Farm Bureau, Inc. (Doc. #14124)............................................................ 89

Irvine Ranch Water District (Doc. #14774).......................................................... 90

Iowa Farmers Union (Doc. #15007)..................................................................... 91

J.R. Simplot Company (Doc. #15062).................................................................. 91

Klamath Water Users Association (Doc. #15063)................................................ 92
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Colorado Cattlemen's Association (Doc. #15068)................................................ 93

American Forest Foundation (Doc. #15093) ........................................................ 94

El Dorado Irrigation District, Placerville, California (Doc. #15231) ................... 94

Union County Cattlemen (Doc. #15261).............................................................. 96

Weyerhaeuser Company (Doc. #15392)............................................................... 96

Minnesota Soybean Growers Association (Doc. #15542).................................... 96

Alabama Farmers Federation (Doc. #16539)........................................................ 97

Missouri Corn Growers Association (Doc. #16569) ............................................ 98

Agribusiness Association of Kentucky et al. (Doc. #18005)................................ 98

New Mexico Cattle Growers Association et al. (Doc. #19595) ......................... 100

Georgia Department of Transportation (Doc. #14282.1).................................... 100

Lake Charles Harbor and Terminal District, Louisiana (Doc. #14448) ............. 100

Airports Council International - North America (Doc. #16370) ........................ 101

Mohave Electric Cooperative, Inc. (Doc. #10953)............................................. 101

Duke Energy (Doc. #13029)............................................................................... 102

Peabody Energy (Doc. #13560).......................................................................... 102

Florida Power and Light Company (Doc. #13615) ............................................ 103

Arizona Public Service Company (Doc. #15162)............................................... 104

Louisville and Jefferson County Metropolitan Sewer District (Doc. #15413)... 104

Orange County Sanitation District, California (Doc. #16335.1) ........................ 104

West Bay Sanitary District, Novato Sanitary District, West County Wastewater 

District, Union Sanitary District and West Valley Sanitation District, California 

(Doc. #16610) ..................................................................................................... 105

Metropolitan Water District of Southern California (Doc. #14637)................... 106

Arizona's Generation & Transmission Cooperatives (Doc. #14901) ................. 106

Utility Water Act Group (Doc. #15016)............................................................. 107

NiSource Inc. (Doc. #15112).............................................................................. 109

Northern Colorado Water Conservancy District, Berthoud, Colorado (Doc. 

#15114) ............................................................................................................... 109

Nebraska Public Power District (Doc. #15126).................................................. 111

Lower Colorado River Authority (Doc. #16332) ............................................... 111

Tri-State Generation and Transmission Association, Inc. (Doc. #16392).......... 112

Texas Water Development Board (Doc. #16563)............................................... 112

Northern California Association (Doc. #17444)................................................. 113

Cloud Peak Energy (Doc. #18010)..................................................................... 114

Tucson Electric Power Company, UNS Energy Corporation (Doc. #19561) .... 114

Chesapeake Bay Foundation (Doc. #14620) ...................................................... 115

National Wildlife Federation (Doc. #15020)...................................................... 116

Center for Biological Diversity, Center for Food Safety, and Turtle Island 

Restoration Network (Doc. #15233)................................................................... 118

American Rivers (Doc. #15372)......................................................................... 122

Center for Science in Public Participation (Doc. #15426).................................. 122

Natural Resources Defense Council et al. (Doc. #15437) .................................. 124

Defenders of Wildlife and Patagonia Area Resource Alliance (Doc. #16394) .. 126

Waterkeeper Alliance et al. (Doc. #16413) ........................................................ 127

Association of State Floodplain Managers, Inc. (Doc. #19452)......................... 128
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American Association of Port Authorities (Doc. #13559).................................. 129

The Association of State Wetland Managers (Doc. #14131) ............................. 130

Earthjustice (Doc. #14564)................................................................................. 130

Center for Rural Affairs (Doc. #15029).............................................................. 131

National Parks Conservation Association (Doc. #15130) .................................. 131

Endangered Habitats League (Doc. #3384)........................................................ 133

George Washington University Regulatory Studies Center (Doc. #13563)....... 133

Citizens Campaign for the Environment (Doc. #14967) .................................... 133

Neuse Riverkeeper Foundation (Doc. #15095) .................................................. 134

Competitive Enterprise Institute et al. (Doc. #15127)........................................ 134

The River Alliance of Wisconsin (Doc. #16344) ............................................... 135

Wyoming Outdoor Council (Doc. #16528) ........................................................ 136

Tennessee Clean Water Network et al. (Doc. #16537)....................................... 136

Kentucky Waterways Alliance (Doc. #16581) ................................................... 137

Lemon Bay Conservancy, Inc. (Doc. #18908.1) ................................................ 139

Water Environment Federation (Doc. #16584) .................................................. 140

Congress of the United States, Senate Committee on Environment and Public 

Works et al. (Doc. #16564)................................................................................. 141

8.1.1. Relevance of Flow Regime........................................................................................ 141

AGENCY SUMMARY RESPONSE.................................................................................. 141

Issue: Jurisdiction over Intermittent and Ephemeral Waters............................. 141

Issue: Legality of Asserting Jurisdiction over Ephemeral Waters..................... 145

Issue: Requirement of “Contribute Flow” ......................................................... 146

Issue: Regulation of Man-Altered Streams........................................................ 147

Issue: Definitions and Clarity ............................................................................ 148

SPECIFIC COMMENTS: ................................................................................................ 148

Tennessee Valley Association (Doc. #17470).................................................... 148

Pueblo of Sandia (Doc. #2729)........................................................................... 149

Rebekah Warren, Michigan State Senator, 18th District (Doc. #4769)............... 150

Pennsylvania Fish and Boat Commission (Doc. #4826) .................................... 150

New York State Attorney General Office et al. (Doc. #6020.1)......................... 150

Quapaw Tribe of Oklahoma (the O-Gah-Pah) (Doc. #7980) ............................. 151

Navajo Nation Environmental Protection Agency (Doc. #10117) ..................... 151

Washington State Senate (Doc. #10871) ............................................................ 151

District Department of the Environment, Government of the District of Columbia 

(Doc. #12716.1) .................................................................................................. 152

Virginia Department of Transportation (Doc. #12756)...................................... 153

Texas Department of Transportation (Doc. #12757).......................................... 154

New Mexico Department of Agriculture (Doc. #13024).................................... 154

State of Wyoming (Doc. #14584)....................................................................... 155

North Carolina Department of Agriculture and Consumer Services (Doc. #14747)

............................................................................................................................. 157

Office of the Governor, State of Kansas (Doc. #14794)..................................... 157

San Carlos Apache Tribe (Doc. #15067)............................................................ 158

Georgia Environmental Protection Division (Doc. #16348) .............................. 158

Attorney General, State of Michigan (Doc. #16469).......................................... 159
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Tennessee Department of Transportation (Doc. #16470)................................... 159

Department of Health and Environmental Control, State of South Carolina (Doc. 

#16491) ............................................................................................................... 160

New Mexico Environment Department (Doc. #16552)...................................... 161

Nebraska Department of Roads (Doc. #16896).................................................. 162

State of Alaska (Doc. #19465)............................................................................ 162

Allen Boone Humphries Robinson LLP (Doc. #19614)..................................... 163

Lincoln County Conservation District, Washington (Doc. #4236) .................... 163

North Cass Water Resource District (Doc. #5491)............................................. 165

Alameda Corridor East Construction Authority et al. (Doc. #8534.1) ............... 166

Pasco County, Florida (Doc. #9697)................................................................... 166

Pikes Peak Area Council of Governments (Doc. #9732) ................................... 167

Clark County Regional Flood Control District (Doc. #11726)........................... 167

Brown County, Kansas (Doc. #13603)............................................................... 167

North Dakota Association of Soil Conservation Districts (Doc. #15168).......... 168

Los Angeles Department of Water and Power (Doc. #15238)........................... 168

Washington County Commission, Utah (Doc. #15448)..................................... 169

Colorado Springs Utilities (Doc. #16351.1) ....................................................... 170

South Kansas Groundwater Management District No. 3, Garden City, Kansas 

(Doc. #16465) ..................................................................................................... 170

Snowmass Water and Sanitation District, Snowmass Village, Colorado (Doc. 

#16529) ............................................................................................................... 171

Water Managers, Kaweah and Tule Watersheds, San Joaquin Valley, California 

(Doc. #16544) ..................................................................................................... 172

County Commissioners, Hot Springs County, Wyoming (Doc. #16676) .......... 173

City of St. Petersburg, Florida (Doc. #18897).................................................... 175

Massachusetts Department of Environmental Protection (Doc. #19133)........... 175

Mississippi Valley Flood Control Association (Doc. #19488)........................... 176

California State Association of Counties (Doc. # 9692)..................................... 177

National Association of Conservation Districts (Doc. #12349) ......................... 177

Colorado Stormwater Council (Doc. #12981).................................................... 178

California Building Industry Association et al. (Doc. #14523).......................... 178

North Carolina Soil and Water Conservation Commission (Doc. #14790)........ 179

Western Urban Water Coalition (Doc. #15178.1) .............................................. 179

John Deere & Company (Doc. #14136.1) .......................................................... 184

Corporate Environmental Enforcement Council, Inc. (Doc. #14608)................ 185

Arizona Chamber of Commerce and Industry (Doc. #14639)............................ 186

Greater Houston Partnership (Doc. #14726) ...................................................... 186

Indiana Cast Metals Association (Doc. #14895.1) ............................................. 187

Landmark Legal Foundation (Doc. #15364) ...................................................... 187

Idaho Association of Commerce & Industry (Doc. #15461).............................. 188

American Council of Engineering Companies (Doc. #15534)........................... 188

GBMC & Associates (Doc. #15770) .................................................................. 189

Federal Water Quality Coalition (Doc. #15822.1).............................................. 191

Action United et al. (Doc. #18859)..................................................................... 195

Southern Nevada Home Builders Association (Doc. #3251) ............................. 195
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The Elm Group, Inc. (Doc. #9688)..................................................................... 196

National Ready Mixed Concrete Association (Doc. #13956) ............................ 197

Building Industry Association of Greater Louisville (Doc. #16449) ................. 198

National Association of Home Builders (Doc. #19540)..................................... 198

New Mexico Mining Association (Doc. #8644)................................................. 211

Reclamation and Abandoned Mine Lands Divisions, Public Service Commission, 

North Dakota (Doc. #12857) .............................................................................. 212

Enefit American Oil (Doc. #13438).................................................................... 212

Arizona Mining Association (Doc. #13951)....................................................... 213

Nevada Mining Association (Doc. #14930) ....................................................... 214

Barrick Gold of North America (Doc. #16914).................................................. 215

Virginia Coal and Energy Alliance and Virginia Mining Issues Group (Doc. 

#18016) ............................................................................................................... 216

Montana Wool Growers Association (Doc. #5843.1) ........................................ 217

Alameda County Cattlewomen (Doc. #8674)..................................................... 218

Maryland Farm Bureau (Doc. #10755)............................................................... 219

Hancock County, Indiana (Doc. #11980) ........................................................... 220

Montana Farm Bureau Federation (Doc. #12715).............................................. 220

Louisiana Cotton and Grain Association (Doc. #12752).................................... 221

Nebraska Cattlemen (Doc. #13018).................................................................... 222

Missouri Agribusiness Association (Doc. #13025) ............................................ 222

Iowa Corn Growers Association (Doc. #13269)................................................. 223

Western Growers Association (Doc. #14130) .................................................... 223

Sugar Cane Growers Cooperative of Florida (Doc. #14283) ............................. 224

Wyoming Farm Bureau Federation (Doc. #14406)............................................ 225

Kansas Farm Bureau (Doc. #14408)................................................................... 226

Kansas Agriculture Alliance (Doc. #14424)....................................................... 227

Oklahoma Pork Council (Doc. #14911) ............................................................. 228

Indiana Corn Growers Association (Doc. #14933)............................................. 229

National Corn Growers Association (Doc. #14968)........................................... 229

Colorado Cattlemen’s Association (Doc. #15068)............................................. 235

North Carolina Farm Bureau Federation (Doc. #15078).................................... 235

Weyerhaeuser Company (Doc. #15392)............................................................. 236

Jensen Livestock and Land LLC (Doc. #15540) ................................................ 236

Dairy Cares (Doc. #16471)................................................................................. 237

Agribusiness Association of Kentucky et al. (Doc. #18005).............................. 238

Frasier Farms (Doc. #18660).............................................................................. 239

Ohio Pork Council (Doc. #19554)...................................................................... 240

Georgia Department of Transportation (Doc. #14282.1).................................... 240

Charlotte-Mecklenburg Storm Water Services (Doc. #3431)............................. 242

Red River Joint Water Resource District (Doc. #4227) ..................................... 242

Florida Federation of Garden Clubs (Doc. #5725)............................................. 243

Beaufort County Stormwater Utility, South Carolina (Doc. #7326.1) ............... 243

Black Hills Corporation (Doc. #6248)................................................................ 245

Northwest Colorado Council of Governments Water Quality/Quantity Committee 

(Doc. #10187) ..................................................................................................... 245
Clean Water Rule Response to Comments – Topic 8: Tributaries

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Mohave Electric Cooperative, Inc. (Doc. #10953)............................................. 246

Duke Energy (Doc. #13029)............................................................................... 247

Murray Energy Corporation (Doc. #13954) ....................................................... 249

County of San Diego, California (Doc. #14782)................................................ 249

Southeast Metro Stormwater Authority (Doc. #14935)...................................... 250

Arizona Public Service Company (Doc. #15162)............................................... 251

Albuquerque Metropolitan Arroyo Flood Control Authority (Doc. #15221)..... 251

Southern Company (Doc. #14134) ..................................................................... 253

CPS Energy (Doc. #14566)................................................................................. 257

Colorado Water Congress Federal Affairs Committee (Doc. #14569)............... 257

Southern Nevada Water Authority (Doc. #14580) ............................................. 258

Santa Clara Valley Water District, California (Doc. #14776)............................ 259

ERO Resources Corporation (Doc. #14914) ...................................................... 259

Utility Water Act Group (Doc. #15016)............................................................. 260

Colorado River Water Conservation District, Colorado (Doc. #15070) ............ 262

Illinois Fertilizer & Chemical Association (Doc. #15129)................................. 263

Idaho Power Company (Doc. #15501) ............................................................... 263

Lower Colorado River Authority (Doc. #16332) ............................................... 263

Basin Electronic Power Cooperative (Doc. #16447).......................................... 265

Cloud Peak Energy (Doc. #18010)..................................................................... 265

Xcel Energy (Doc. #18023)................................................................................ 266

Ducks Unlimited (Doc. #11014)......................................................................... 267

Choose Clean Water Coalition et al. (Doc. #11773.1) ....................................... 267

Southern Environmental Law Center et al. (Doc. #13610) ................................ 269

National Wildlife Federation (Doc. #15020)...................................................... 271

American Rivers (Doc. #15372)......................................................................... 275

Western Resource Advocates (Doc. #16460)..................................................... 276

National Waterways Conference, Inc. (Doc. #12979)........................................ 280

Trout Unlimited (Doc. #18015).......................................................................... 281

Environment Council of Rhode Island (Doc. #3532)......................................... 281

Clean Water Action et al. (Doc. #13997) ........................................................... 282

Kansas Natural Resource Council (Doc. #14599).............................................. 282

Mystic River Watershed Association (Doc. #14633) ......................................... 283

Citizens Committee to Complete the Refuge (Doc. #14738.1) .......................... 283

Montana Audubon (Doc. #14755)...................................................................... 283

Clean Water Action et al. (Doc. #14884) ........................................................... 284

Amigos Bravos (Doc. #14974) ........................................................................... 285

Clean Water Action Maryland et al. (Doc. #15072)........................................... 287

Environmental Justice Coalition for Water (Doc. #15105) ................................ 288

Friends of the Cacapon River (Doc. #15121)..................................................... 289

Tulane Environmental Law Clinic et al (Doc. #15123)...................................... 289

Audubon California et al. (Doc. #15200) ........................................................... 296

Western Pennsylvania Conservancy (Doc. #15202)........................................... 297

Center for Water Advocacy et al. (Doc. #15225) ............................................... 297

Hackensack Riverkeeper, Hudson Riverkeeper, Milwaukee Riverkeeper, New 

York/New Jersy Baykeeper and Raritan Riverkeeper (Doc. #15360)................ 298
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Sierra Club, Cumberland Chapter (Doc. #15466) .............................................. 298

Wisconsin Wetlands Association (Doc. #15629) ............................................... 299

Friends of the Rappahannock (Doc. #15864) ..................................................... 300

Regulatory Environmental Group for Missouri (Doc. #16337.1)....................... 300

Charles River Conservancy et al. (Doc. #16453) ............................................... 301

Defenders of Wildlife and Patagonia Area Resource Alliance (Doc. #16394) .. 301

Michigan United Conservation Clubs (Doc. #16395) ........................................ 305

Waterkeeper Alliance et al. (Doc. #16413) ........................................................ 305

Wyoming Outdoor Council (Doc. #16528) ........................................................ 307

Tennessee Clean Water Network et al. (Doc. #16537)....................................... 308

Audubon Society of Greater Denver (Doc. #16934) .......................................... 308

Warm Springs Watershed Association (Doc. #18019)....................................... 309

Upper Mississippi, Illinois, & Missouri Rivers Association (Doc. #19563)...... 309

Society for Freshwater Science (Doc. #11783) .................................................. 310

Consortium of Aquatic Scientific Societies (Doc. #14802)................................ 310

United States Senate (Doc. #19655)................................................................... 311

United States House of Representatives (Doc. #17458)..................................... 311

8.1.2. Ordinary High Water Mark (OHWM)...................................................................... 312

AGENCY SUMMARY RESPONSE.................................................................................. 312

Issue: Use of OHWM inappropriate/appropriate – will lead to over/under 

coverage of features............................................................................................ 312

Issue: Need more guidance on determining OHWM and definitions of bed and 

banks and OHWM .............................................................................................. 316

SPECIFIC COMMENTS ................................................................................................. 318

Washington State Department of Ecology et al. (Doc. #13957)......................... 318

Alabama Department of Transportation (Doc. #14116)..................................... 319

Commonwealth Pennsylvania Department of Agriculture (Doc. #14465)......... 319

Alameda Corridor East Construction Authority et al. (Doc. #8534.1) ............... 319

Kendall County Board, Illinois (Doc. #10965)................................................... 320

Board of County Commissioners, Churchill County, Nevada (Doc. #12260) ... 320

Weld County, Colorado (Doc. #12343).............................................................. 321

Brown County, Kansas (Doc. #13603)............................................................... 322

Board of Supervisors, San Joaquin County, California (Doc. #15017.1)........... 322

Painesville Township, Ohio (Doc. #15183)........................................................ 323

Brady Township Supervisors, Clearfield County, Pennsylvania (Doc. #16480) 323

Sienna Plantation Levee Improvement District, Sugar Land, Texas (Doc. #17455)

............................................................................................................................. 324

Butte County, California (Doc. #19593)............................................................. 325

Association of California Water Agencies (Doc. #12978)................................. 325

Colorado Stormwater Council (Doc. #12981).................................................... 327

Flood Control and Water Conservation District, Riverside County, California 

(Doc. #14581) ..................................................................................................... 327

Western Urban Water Coalition (Doc. #15178.1) .............................................. 328

State of Nevada Department of Conservation et al. (Doc. #16932) ................... 330

Montana Association of Conservation Districts (Doc. #18628)......................... 330

Water Advocacy Coalition (Doc. #7981) ........................................................... 331
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John Deere & Company (Doc. #14136.1) .......................................................... 332

Arizona Chamber of Commerce and Industry (Doc. #14639)............................ 333

Steel Manufacturers Association and Specialty Steel Industry of North America 

(Doc. #15416) ..................................................................................................... 333

GBMC & Associates (Doc. #15770) .................................................................. 333

Water Advocacy Coalition (Doc. #17921.1) ...................................................... 334

National Association of Home Builders (Doc. #19540)..................................... 336

Minnkota Power Cooperative, Inc. (Doc. #19607)............................................. 338

American Society of Civil Engineers (Doc. #19572)......................................... 339

Southpace Properties, Inc. (Doc. #6989) ............................................................ 339

Kerr Environmental Services Corp. (Doc. #7937.1)........................................... 339

Portland Cement Association (Doc. #13271) ..................................................... 340

El Dorado Holdings, Inc. (Doc. #14285)............................................................ 341

NAIOP Commercial Real Estate Development Association (Doc. #14621)...... 342

South Carolina Forest Association (Doc. #6855) ............................................... 343

Kansas Independent Oil & Gas Association (Doc. #12249)............................... 343

Pennsylvania Coal Alliance (Doc. #13074)........................................................ 344

Enefit American Oil (Doc. #13438).................................................................... 344

Arizona Mining Association (Doc. #13951)....................................................... 345

Freeport-McMoRan Inc. (Doc. #14135, #14135.1 and #14135.2)..................... 349

Wyoming Mining Association (Doc. #14460).................................................... 353

Devon Energy Corporation (Doc. #14916)......................................................... 354

National Mining Association (Doc. #15059)...................................................... 354

National Sustainable Agriculture Coalition (Doc. #15403)................................ 355

Halliburton Energy Services, Inc. (Doc. #15509)............................................... 355

Pennsylvania Grade Crude Oil Coalition (Doc. #15773) ................................... 356

Dominion Resources Services, Inc. (Doc. #16338)............................................ 356

Washington Cattlemen’s Association (Doc. #3723)........................................... 357

Oregon Cattlemen’s Association (Doc. #5273.1)............................................... 357

National Farmers Union (Doc. #6249) ............................................................... 357

Alameda County Cattlewomen (Doc. #8674)..................................................... 358

Glenn County Rangeland Association (Doc. #12724)........................................ 360

Colorado Farm Bureau (Doc. #12829) ............................................................... 360

Bayless and Berkalew Co. (Doc. #12967).......................................................... 360

North American Meat Association and American Meat Institute (Doc. #13071)

............................................................................................................................. 361

National Chicken Council, National Turkey Federation, and U.S. Poultry & Egg 

Association (Doc. #14469) ................................................................................. 361

Minnesota Farm Bureau (Doc. #14653) ............................................................. 362

Irvine Ranch Water District (Doc. #14774)........................................................ 362

California Association of Winegrape Growers (Doc. #14593) .......................... 363

Monarch-Chesterfield Levee District, St. Louis, Missouri (Doc. #14904) ........ 364

North Carolina Farm Bureau Federation (Doc. #15078).................................... 365

Snell & Wilmer L.L.P. (Doc. #15206)................................................................ 366

Missouri Farm Bureau Federation (Doc. #15224).............................................. 367

Weyerhaeuser Company (Doc. #15392)............................................................. 367
Clean Water Rule Response to Comments – Topic 8: Tributaries

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Utah Farm Bureau Federation (Doc. #16542.1) ................................................. 369

Iowa Farm Bureau Federation (Doc. #15633.1)................................................. 369

Riverport Levee District (Doc. #15655)............................................................. 370

Greene County Farm Bureau (Doc. #17007)...................................................... 371

Agribusiness Association of Kentucky et al. (Doc. #18005).............................. 371

Wilkin County Farm Bureau (Doc. #19489) ...................................................... 372

American Water Company (Doc. #6935.1)........................................................ 373

Northwest Colorado Council of Governments Water Quality/Quantity Committee 

(Doc. #10187) ..................................................................................................... 373

Duke Energy (Doc. #13029)............................................................................... 374

Murray Energy Corporation (Doc. #13954) ....................................................... 375

Department of Public Works, City of Northglenn, Colorado (Doc. #14990)..... 375

Arizona Public Service Company (Doc. #15162)............................................... 376

Louisville and Jefferson County Metropolitan Sewer District (Doc. #15413)... 376

West Bay Sanitary District, Novato Sanitary District, West County Wastewater 

District, Union Sanitary District and West Valley Sanitation District, California 

(Doc. #16610) ..................................................................................................... 377

Southern Company (Doc. #14134) ..................................................................... 377

Metropolitan Water District of Southern California (Doc. #14637)................... 378

Nucor Corp. (Doc. #14963) ................................................................................ 380

Pennsylvania Independent Oil and Gas Association (Doc. #15167).................. 381

Lower Colorado River Authority (Doc. #16332) ............................................... 381

Tri-State Generation and Transmission Association, Inc. (Doc. #16392).......... 381

Northern California Association (Doc. #17444)................................................. 382

Ducks Unlimited (Doc. #11014)......................................................................... 382

Southern Environmental Law Center et al. (Doc. #13610) ................................ 383

The Wildlife Society (Doc. #14899)................................................................... 384

Potomac Riverkeeper, Inc. (Doc. #15013).......................................................... 385

National Wildlife Federation (Doc. #15020)...................................................... 385

American Rivers (Doc. #15372)......................................................................... 387

Western Resource Advocates (Doc. #16460)..................................................... 389

National Waterways Conference, Inc. (Doc. #12979)........................................ 389

Earthjustice (Doc. #14564)................................................................................. 390

Center for Rural Affairs (Doc. #15029).............................................................. 391

Texas Wildlife Association (Doc. #12251) ........................................................ 391

Protect Americans Now (Doc. #12726).............................................................. 391

Citizens Committee to Complete the Refuge (Doc. #14738.1) .......................... 392

Los Angeles Waterkeepers (Doc. #15060)......................................................... 392

Delaware Riverkeeper Network (Doc. #15383) ................................................. 393

Missouri and Associated Rivers Coalition (Doc. #15528) ................................. 394

Defenders of Wildlife and Patagonia Area Resource Alliance (Doc. #16394) .. 394

Waterkeeper Alliance et al. (Doc. #16413) ........................................................ 395

Congress of the United States, Senate Committee on Environment and Public 

Works et al. (Doc. #16564)................................................................................. 397

O'Neil LLP (Doc. #16559).................................................................................. 398

8.2. INCLUSION OF WETLANDS, LAKES, DITCHES AS TRIBUTARIES ..................................... 398
Clean Water Rule Response to Comments – Topic 8: Tributaries

12

AGENCY SUMMARY RESPONSE.................................................................................. 398

Issue: Wetlands, Lakes, and Ponds.................................................................... 399

Issue: Ditches as Tributary................................................................................. 400

SPECIFIC COMMENTS ................................................................................................. 401

Region 10 Tribal Caucus (Doc. #14927)............................................................ 401

Pueblo of Sandia (Doc. #2729)........................................................................... 401

Missouri Department of Transportation (Doc. #3313) ....................................... 402

Virginia Department of Transportation (Doc. #12756)...................................... 402

North Carolina Forest Service, North Carolina Department of Agriculture (Doc. 

#14122) ............................................................................................................... 403

Texas Commission on Environmental Quality (Doc. #14279)........................... 404

North Dakota Office of the Governor et al. (Doc. #15365)................................ 404

Ohio Department of Natural Resources et al. (Doc. #15421)............................. 405

Attorney General, State of Michigan (Doc. #16469).......................................... 407

Tennessee Department of Transportation (Doc. #16470)................................... 408

State of South Dakota (Doc. #16925)................................................................. 408

State of Alaska (Doc. #19465)............................................................................ 409

Skamania County Board of Commissioners, Washington (Doc. #2469.1) ........ 410

Franconia Township, Pennsylvania (Doc. #8661).............................................. 410

Murray County Board of Commissioners (Doc. #7528) .................................... 410

City of Chesapeake, Virginia (Doc. #9615)........................................................ 412

County of Henry, Virginia (Doc. #10949).......................................................... 413

Board of County Commissioners, Otero County, New Mexico (Doc. #14321). 413

New Mexico Environment Department (Doc. #16552)...................................... 413

Bureau of Environmental Services, City of Portland, Oregon (Doc. #16662) ... 414

Dolores Water Conservancy District and Southwestern Water Conservation 

District, Colorado (Doc. #19461) ....................................................................... 414

North Dakota Water Resource Districts Association (Doc. #5596) ................... 416

Nebraska Association of Resources Districts (Doc. #11855)............................. 416

California Association of Sanitation Agencies (Doc. #12832)........................... 417

Association of California Water Agencies (Doc. #12978)................................. 418

Western Coalition of Arid States (Doc. #14407)................................................ 418

Rhode Island Rivers Council (Doc. #16367)...................................................... 420

Washington State Water Resources Association (Doc. #16543)........................ 420

Michigan Association of Conservation Districts (Doc. #16583)........................ 421

Federal Water Quality Coalition (Doc. #15822.1).............................................. 422

Water Advocacy Coalition (Doc. #17921.1) ...................................................... 422

Virginia Manufacturers Association (Doc. #18821)........................................... 423

Action United et al. (Doc. #18859)..................................................................... 424

Minnkota Power Cooperative, Inc. (Doc. #19607)............................................. 424

Kerr Environmental Services Corp. (Doc. #7937.1)........................................... 424

Portland Cement Association (Doc. #13271) ..................................................... 426

Associated General Contractors of America (Doc. #14602) .............................. 429

Vulcan Materials Company (Doc. #14642)........................................................ 430

National Association of Home Builders (Doc. #19540)..................................... 431

New Mexico Mining Association (Doc. #8644)................................................. 434
Clean Water Rule Response to Comments – Topic 8: Tributaries

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Kansas Independent Oil & Gas Association (Doc. #12249)............................... 435

Alliance Coal, LLC (Doc. #14577)..................................................................... 436

Devon Energy Corporation (Doc. #14916)......................................................... 437

Sinclair Oil Corporation (Doc. #15142) ............................................................. 437

Ohio Coal Association (Doc. #15163)................................................................ 438

National Sustainable Agriculture Coalition (Doc. #15403)................................ 438

Pennsylvania Aggregates and Concrete Association (Doc. #16353).................. 439

National Farmers Union (Doc. #6249) ............................................................... 440

Alameda County Cattlewomen (Doc. #8674)..................................................... 441

Michigan Farm Bureau (Doc. #10196)............................................................... 443

North American Meat Association and American Meat Institute (Doc. #13071)

............................................................................................................................. 443

Kennewick Irrigation District, Kennewick, Washington (Doc. #13571) ........... 444

American Exploration & Mining Association (Doc. #13616)............................ 444

Western Growers Association (Doc. #14130) .................................................... 445

National Corn Growers Association (Doc. #14968)........................................... 445

Klamath Water Users Association (Doc. #15063).............................................. 446

Union County Cattlemen (Doc. #15261)............................................................ 446

Beet Sugar Development Foundation (Doc. #15368)......................................... 447

Jensen Livestock and Land LLC (Doc. #15540) ................................................ 448

Florida Crystals Corporation (Doc. #16652) ...................................................... 449

North Dakota Farmers Union (Doc. #16930.1) .................................................. 450

Agribusiness Association of Kentucky et al. (Doc. #18005).............................. 450

Hampton Roads Planning District Commission, Chesapeake, Virginia (Doc. 

#9612) ................................................................................................................. 451

Georgia Department of Transportation (Doc. #14282.1).................................... 451

Department of Public Works, City of Chesapeake, Virginia (Doc. #5612.1) .... 452

Black Hills Corporation (Doc. #6248)................................................................ 453

Clearwater Watershed District et al. (Doc. #9560.1).......................................... 453

Central Massachusetts Regional Stormwater Coalition (Doc. #15443.1) .......... 454

Duke Energy (Doc. #13029)............................................................................... 454

Murray Energy Corporation (Doc. #13954) ....................................................... 455

Southern Company (Doc. #14134) ..................................................................... 456

Santa Clara Valley Water District, California (Doc. #14776)............................ 457

Nucor Corp. (Doc. #14963) ................................................................................ 457

Colorado River Water Conservation District, Colorado (Doc. #15070) ............ 458

Illinois Fertilizer & Chemical Association (Doc. #15129)................................. 458

Tri-State Generation and Transmission Association, Inc. (Doc. #16392).......... 459

Texas Water Development Board (Doc. #16563)............................................... 459

Ducks Unlimited (Doc. #11014)......................................................................... 459

Southern Environmental Law Center et al. (Doc. #13610) ................................ 460

Chesapeake Bay Foundation (Doc. #14620) ...................................................... 461

National Wildlife Federation (Doc. #15020)...................................................... 462

American Rivers (Doc. #15372)......................................................................... 465

Natural Resources Defense Council et al. (Doc. #15437) .................................. 465

National Federation of Independent Business (Doc. #8319).............................. 467
Clean Water Rule Response to Comments – Topic 8: Tributaries

14

Earthjustice (Doc. #14564)................................................................................. 467

Center for Rural Affairs (Doc. #15029).............................................................. 468

Alabama Rivers Alliance (Doc. #14280)............................................................ 468

Atlanta Audubon Society (Doc. #14281)............................................................ 469

Clean Water Action et al. (Doc. #14884) ........................................................... 470

Conservancy of Southwest Florida (Doc. #14980)............................................. 470

Clean Water Action Maryland et al. (Doc. #15072)........................................... 471

Tulane Environmental Law Clinic et al (Doc. #15123)...................................... 471

Stormwater Management Commission, Lake County, Illinois (Doc. #15381) .. 471

Wisconsin Wetlands Association (Doc. #15629) ............................................... 472

The River Alliance of Wisconsin (Doc. #16344) ............................................... 472

Defenders of Wildlife and Patagonia Area Resource Alliance (Doc. #16394) .. 473

Michigan United Conservation Clubs (Doc. #16395) ........................................ 473

Waterkeeper Alliance et al. (Doc. #16413) ........................................................ 474

Red River Valley Association (Doc. #16432) .................................................... 475

Ruby Valley Conservation District, Montana (Doc. #16477) ............................ 476

Society for Freshwater Science (Doc. #11783) .................................................. 476

Florida Stormwater Association (Doc. #14613)................................................. 477

Robert J. Pierce, PhD, Wetland Science Applications, Inc. (Doc. #4958) ......... 477

O'Neil LLP (Doc. #16559).................................................................................. 478

8.3. RELEVANCE OF BREAKS IN OHWM............................................................................... 478

AGENCY SUMMARY RESPONSE.................................................................................. 478

Issue: General Comments Opposing and Supporting Approach to Break in 

OHWM ............................................................................................................... 478

Issue: Difficulties in determining OHWM, length of break, and contribution of 

flow ..................................................................................................................... 479

Issue: Break in OHWM should sever jurisdiction ............................................. 481

SPECIFIC COMMENTS ................................................................................................. 483

U.S. House of Representatives Committee on Space, Science and Technology 

(Doc. #16386) ..................................................................................................... 483

North Carolina Department of Environment and Natural Resources (Doc. #14984)

............................................................................................................................. 483

San Carlos Apache Tribe (Doc. #15067)............................................................ 484

Ohio Department of Natural Resources et al. (Doc. #15421)............................. 484

California Department of Transportation, Division of Environmental Analysis 

(Doc. #19538) ..................................................................................................... 485

Western Coalition of Arid States (Doc. #14407)................................................ 486

Flood Control and Water Conservation District, Riverside County, California 

(Doc. #14581) ..................................................................................................... 486

City of Buckeye, Arizona (Doc. #14591)........................................................... 486

American Foundry Society (Doc. #15148)......................................................... 486

Federal StormWater Association (Doc. #15161)................................................ 487

Water Advocacy Coalition (Doc. #17921.1) ...................................................... 488

Kerr Environmental Services Corp. (Doc. #7937.1)........................................... 488

El Dorado Holdings, Inc. (Doc. #14285)............................................................ 489

National Association of Home Builders (Doc. #19540)..................................... 491
Clean Water Rule Response to Comments – Topic 8: Tributaries

15

Pennsylvania Coal Alliance (Doc. #13074)........................................................ 492

National Stone, Sand and Gravel Association (Doc. #14412)............................ 492

Halliburton Energy Services, Inc. (Doc. #15509)............................................... 493

Alpha Natural Resources, Inc. (Doc. #15624).................................................... 493

Pennsylvania Grade Crude Oil Coalition (Doc. #15773) ................................... 496

Dominion Resources Services, Inc. (Doc. #16338)............................................ 496

Pennsylvania Aggregates and Concrete Association (Doc. #16353).................. 496

Montana Farm Bureau Federation (Doc. #12715).............................................. 497

National Chicken Council, National Turkey Federation, and U.S. Poultry & Egg 

Association (Doc. #14469) ................................................................................. 497

Charlotte-Mecklenburg Storm Water Services (Doc. #3431)............................. 498

Duke Energy (Doc. #13029)............................................................................... 498

EcoSynthesis Scientific & Regulatory Services (Doc. #14586)......................... 499

Metropolitan Water District of Southern California (Doc. #14637)................... 499

ERO Resources Corporation (Doc. #14914) ...................................................... 499

Pennsylvania Independent Oil and Gas Association (Doc. #15167).................. 500

Defenders of Wildlife and Patagonia Area Resource Alliance (Doc. #16394) .. 500

Western Resource Advocates (Doc. #16460)..................................................... 501

Missouri Coalition for the Environment (Doc. #16372)..................................... 502

O'Neil LLP (Doc. #16559).................................................................................. 503

8.4. TRIBUTARIES DISTINGUISHED FROM NON-JURISDICTIONAL GULLIES, RILLS, NONWETLAND SWALES..................................................................................................................... 503

AGENCY SUMMARY RESPONSE.................................................................................. 503

Issue: Distinction between an ephemeral water and a non-jurisdictional gulley, 

rill or non-wetland swale .................................................................................... 503

Issue: Need for additional factors and specific guidance and methodology on 

determining bed and banks and OHWM, especially in the arid West. ............... 506

Issue: Lack of clarity problematic for certain sectors including farming, ranching, 

and mining. ......................................................................................................... 508

SPECIFIC COMMENTS ................................................................................................. 510

U.S. House of Representatives Committee on Space, Science and Technology 

(Doc. #16386) ..................................................................................................... 510

North Carolina Department of Agriculture and Consumer Services (Doc. #14747)

............................................................................................................................. 510

State of Oregon (Doc. #15218)........................................................................... 511

Ohio Department of Natural Resources et al. (Doc. #15421)............................. 511

City of Chesapeake, Virginia (Doc. #9615)........................................................ 512

County of Henry, Virginia (Doc. #10949).......................................................... 513

Board of Supervisors, Maricopa County, Arizona (Doc. #14132.1) .................. 513

Washington County Commission, Utah (Doc. #14991)..................................... 514

South Big Horn County Conservation District, Wyoming (Doc. #17264)......... 514

Virginia Department of Transportation (Doc. #12756)...................................... 514

Association of Clean Water Administrators (Doc. #13069)............................... 515

Western Coalition of Arid States (Doc. #14407)................................................ 515

Western Urban Water Coalition (Doc. #15178.1) .............................................. 515
Clean Water Rule Response to Comments – Topic 8: Tributaries

16

California Department of Transportation, Division of Environmental Analysis 

(Doc. #19538) ..................................................................................................... 518

Arizona Chamber of Commerce and Industry (Doc. #14639)............................ 518

Aluminum Association (Doc. #15388)............................................................... 519

National Association of Manufacturers (Doc. #15410)...................................... 520

American Council of Engineering Companies (Doc. #15534)........................... 521

Business Council of Alabama (Doc. #15538)..................................................... 521

GBMC & Associates (Doc. #15770) .................................................................. 522

Federal Water Quality Coalition (Doc. #15822.1).............................................. 522

Water Advocacy Coalition (Doc. #17921.1) ...................................................... 524

National Association of Home Builders (Doc. #19540)..................................... 526

Pennsylvania Coal Alliance (Doc. #13074)........................................................ 527

Newmont Mining Corporation (Doc. #13596) ................................................... 527

Arizona Mining Association (Doc. #13951)....................................................... 528

Freeport-McMoRan Inc. (Doc. #14135 and Doc. #14135.1) ............................. 529

The Mosiac Company (Doc. #14640)................................................................. 533

National Mining Association (Doc. #15059)...................................................... 534

Halliburton Energy Services, Inc. (Doc. #15509)............................................... 539

Alpha Natural Resources, Inc. (Doc. #15624).................................................... 540

Dominion Resources Services, Inc. (Doc. #16338)............................................ 541

Alameda County Cattlewomen (Doc. #8674)..................................................... 542

Montana Farm Bureau Federation (Doc. #12715).............................................. 542

North American Meat Association and American Meat Institute (Doc. #13071)

............................................................................................................................. 543

Kennewick Irrigation District, Kennewick, Washington (Doc. #13571) ........... 544

Kansas Agriculture Alliance (Doc. #14424)....................................................... 544

Georgia Paper & Forest Products Association (Doc. #14924) ........................... 545

North Carolina Farm Bureau Federation (Doc. #15078).................................... 545

Missouri Farm Bureau Federation (Doc. #15224).............................................. 546

National Alliance of Forest Owners (Doc. #15247)........................................... 547

American Forest & Paper Association (Doc. #15420) ....................................... 548

Jensen Livestock and Land LLC (Doc. #15440) ................................................ 549

Iowa Farm Bureau Federation (Doc. #15633.1)................................................. 549

Montana Stockgrowers Association (Doc. #16937)........................................... 550

Greene County Farm Bureau (Doc. #17007)...................................................... 551

Agribusiness Association of Kentucky et al. (Doc. #18005).............................. 551

Department of Public Works, City of Chesapeake, Virginia (Doc. #5612.1) .... 552

Duke Energy (Doc. #13029)............................................................................... 552

Southern Company (Doc. #14134) ..................................................................... 553

EcoSynthesis Scientific & Regulatory Services (Doc. #14586)......................... 554

ERO Resources Corporation (Doc. #14914) ...................................................... 557

American Public Power Association (Doc. #15008).......................................... 558

Colorado River Water Conservation District, Colorado (Doc. #15070) ............ 558

Association of Metropolitan Water Agencies et al. (Doc. #15157).................... 559

Pennsylvania Independent Oil and Gas Association (Doc. #15167).................. 559

Wisconsin Electric Power Company and Wisconsin Gas LLC (Doc. #15407).. 560
Clean Water Rule Response to Comments – Topic 8: Tributaries

17

Southern Environmental Law Center et al. (Doc. #13610) ................................ 560

Center for Biological Diversity, Center for Food Safety, and Turtle Island 

Restoration Network (Doc. #15233)................................................................... 561

Natural Resources Defense Council et al. (Doc. #15437) .................................. 561

Association of State Floodplain Managers, Inc. (Doc. #19452)......................... 562

The Association of State Wetland Managers (Doc. #14131) ............................. 563

Texas Wildlife Association (Doc. #12251) ........................................................ 563

Wyoming Outdoor Council (Doc. #16528) ........................................................ 564

Office of the Governor, State of Utah (Doc. #16534) ........................................ 566

U.S. Senators Jeff Flake and John McCain (Doc. #1377) .................................. 566

Environmental Technology Consultants (Doc. #2597) ...................................... 567

Whitman, Requardt & Associates, LLP (Doc. #1330) ....................................... 567

8.5. SUPPLEMENTAL COMMENTS ON TRIBUTARIES .............................................................. 568

SPECIFIC COMMENTS ................................................................................................. 568

Anonymous (Doc. #3300.1)............................................................................... 568

L. Banks (Doc. #5554.2).................................................................................... 569

Anonymous (Doc. #7447).................................................................................. 569

Office of the Administrator, Science Advisory Board, U.S. Environmental 

Protection Agency (Doc. #7531) ....................................................................... 569

Board of Douglas County Commissioners, Castle Rock, CO (Doc. #8145)...... 570

Terry E. Branstad, Governor, State of Iowa et al. (Doc. #8377) ........................ 571

Southern California Association of Governments (Doc. #8534.1)..................... 571

B. Forman (Doc. #9065)..................................................................................... 571

Michael Richard (Doc. #9291) ........................................................................... 571

RiverStone Group, Inc. (Doc. #10742)............................................................... 572

County of Henry, Collinsville, Virginia (Doc. #10949)..................................... 573

Anonymous (Doc. #11304)................................................................................. 573

Anonymous (Doc. #11350)................................................................................. 573

T. Walsh (Doc. #11437)...................................................................................... 574

Anonymous (Doc. #11481)................................................................................. 574

Norton County Road & Bridge (Doc. #11746)................................................... 575

Anonymous (Doc. #11761)................................................................................. 576

Jack Kearns (Doc. #11860)................................................................................. 577

Vicki Watson (Doc. #12081)............................................................................. 577

Office of the Board Attorney, Board of Supervisors Jackson County, Mississippi 

(Doc. #12262) ..................................................................................................... 577

Mesa County, Colorado Board of County Commissioners (Doc. #12713) ........ 578

Milan Township Board of Trustees (Doc. #13044)............................................ 578

Jason Reott (Doc. #13199).................................................................................. 579

NRG Energy, Inc. (Doc. #13995)....................................................................... 580

Todd Wilkinson (Doc. #13443).......................................................................... 580

Newmont Mining Corporation (Doc. #13596) ................................................... 581

Southern Environmental Law Center et al. (Doc. #13610) ................................ 582

D. Fleming (Doc. #13654).................................................................................. 582

Tamara Choat (Doc. #13701) ............................................................................. 583

Big Horn County State of Wyoming (Doc. #14571).......................................... 584
Clean Water Rule Response to Comments – Topic 8: Tributaries

18

Waters of the United States Coalition (Doc. #14589) ........................................ 585

The Clean Energy Group Waters Initiative (Doc. #14616)................................ 585

State of Oklahoma (Doc. #14773) ...................................................................... 586

Patti Buck (Doc. #14825) ................................................................................... 587

Clean Water Action (Doc. #15015) .................................................................... 587

The Heritage Foundation (Doc. #15055)............................................................ 589

Lea Soil and Conservation District Board of Supervisors (Doc. #15144.1)....... 590

Arizona Department of Transportation (Doc. #15215)....................................... 591

Southern Ute Indian Tribe Growth Fund (Doc. #15386).................................... 592

Wyoming County Commissioners Association (Doc. #15434).......................... 592

Pennsylvania Farm Bureau (Doc. #15508)......................................................... 593

Countrymark Cooperative Holding Corporation, LLC; Countrymark Refining and 

Logistics, LLC (Doc. #15656)............................................................................ 594

K. Ransford (Doc. #15675)................................................................................. 597

Anonymous (Doc. #16234)................................................................................. 597

North Dakota Farmers Union (Doc. #16390) ..................................................... 597

Virginia Poultry Federation (Doc. #16604)........................................................ 598

D. Gillham (Doc. #16906) .................................................................................. 599

Shasta County Farm Bureau (Doc. #16924)....................................................... 599

Arizona Rock Products Association (Doc. #17055)........................................... 599

Atlantic Legal Foundation (Doc. #17361).......................................................... 601

D. Furtado (Doc. #17659)................................................................................... 602

A. Cilimburg (Doc. #17667)............................................................................... 602

D. Parsons (Doc. #17789)................................................................................... 602

J. Holder (Doc. #17999)...................................................................................... 602

R. McKinnon (Doc. #18845) ............................................................................. 603

Donald Shawcroft (Doc. #18569)....................................................................... 603

Anonymous (Doc. #18801)................................................................................. 604

City of Olathe Kansas (Doc. #18982)................................................................. 604

Jon Klingel (Doc. #19166).................................................................................. 604

J. R. Dorney (Doc. #19235)................................................................................ 607

Halliburton Energy Services, Inc. (Doc. #19458)............................................... 608

REFERENCES............................................................................................................................... 609

SUPPLEMENTAL REFERENCES ................................................................................................... 631
Clean Water Rule Response to Comments – Topic 8: Tributaries

19

Topic 8. TRIBUTARIES

8.1. DEFINITION

Agency Summary Response

The agencies received many comments in response to the proposed definition of “tributary” in 

the proposed rule. The proposed rule defined “tributary” as: 

“a water physically characterized by the presence of a bed and banks and 

ordinary high water mark, as defined at 33 CFR 328.3(e), which contributes flow, 

either directly or through another water, to a water identified in paragraphs (1)(i) 

through (iv) of this definition. In addition, wetlands, lakes, and ponds are 

tributaries (even if they lack a bed and banks or ordinary high water mark) if they 

contribute flow, either directly or through another water to a water identified in 

paragraphs (1)(i) through (iii) of this definition. A water that otherwise qualifies 

as a tributary under this definition does not lose its status as a tributary if, for any 

length, there are one or more man-made breaks (such as bridges, culverts, pipes, 

or dams), or one or more natural break (such as wetlands at the head of or along 

the run of a stream, debris piles, boulder fields, or a stream that flows 

underground) so long as a bed and banks and an ordinary high water mark can 

be identified upstream of the break. A tributary, including wetlands, can be a 

natural, man-altered, or man-made water and includes waters such as rivers, 

streams, lakes, ponds, impoundments, canals, and ditches not excluded in 

paragraph (2)(iii) or (iv) of this definition.”

Many commenters indicated that the proposed definition of “tributary” was ambiguous and

would result in jurisdiction asserted over many waters that have not previously been considered

jurisdictional. Commenters expressed particular concerns with intermittent and ephemeral 

waters and artificial or man-made waters, such as canals and ditches. A number of commenters 

questioned the agencies’ legal ability to assert jurisdiction over such waters, especially 

ephemeral waters and man-made waters. Other commenters supported the proposed inclusion of 

intermittent, ephemeral and man-made waters as tributaries, when those waters functioned as 

tributaries. Many commenters expressed concern that the proposed definition would consider 

ditches, especially stormwater conveyances, as waters of the United States even where such 

features were already regulated as point sources under the National Pollutant Discharge 

Elimination System (NPDES).

Many commenters raised concerns with the proposed definition’s characterization of 

“contributes flow,” and suggested that this could subject nearly any water located anywhere on 

the landscape to jurisdiction as a tributary. Many commenters did not agree that waters such as 

wetlands, lakes, ponds and impoundments should be considered tributaries. These commenters 

believed that including such waters as tributaries rendered the definition confusing, illogical and 
Clean Water Rule Response to Comments – Topic 8: Tributaries

20

contrary to the public’s common understanding of the term “tributary” as a channel or stream 

characterized by flowing water.

Many commenters were uncomfortable with the use of ordinary high water mark (OHWM) in 

the definition of tributary due to inconsistent identification of OHWM indicators regionally and 

among the agencies’ field staff. Other commenters supported the use of OHWM and bed and 

banks as physical indicators of tributaries. Numerous commenters were concerned that the 

jurisdictional status of a tributary would be extended upstream of a natural or man-made break in 

the OHWM and/or presence of bed and bank if such features existed upstream of a break. 

The final rule is similar to the proposal, but important revisions and clarifications have been 

made in response to public comments. The definition of “tributary” in the final rule requires that 

flow must be of sufficient volume, frequency, and duration to create the physical characteristics 

of bed and banks and an OHWM. The rule includes ephemeral streams that meet the definition 

of tributary as waters of the United States, because the agencies determined that such streams 

provide important functions for downstream waters, and in combination with other protected 

tributaries in a watershed significantly affect the chemical, physical, and biological integrity of 

traditional navigable waters, interstate waters, and the territorial seas. If a water lacks sufficient 

flow to create the physical characteristics of bed and banks and an OHWM, it is not considered 

“tributary” under the rule. To further emphasize this point, the final rule expressly indicates in 

paragraph (b) that ephemeral reaches that do not meet the definition of tributary are not waters of 

the United States.

CWA jurisdiction has historically been asserted over intermittent and ephemeral waters. The 

longstanding regulatory definition of “waters of the United States” included “tributaries” without 

any limitations regarding volume or duration of flow. The December 2008 Guidance on postRapanos implementation noted that tributaries that flow only in direct response to rainfall are 

subject to the CWA if they have a significant nexus to a downstream traditional navigable water, 

and that intermittent or seasonal streams were jurisdictional without the need for a case-specific 

showing of significant nexus. Federal court decisions, some of which are decades old, have 

supported assertions that intermittent and ephemeral waters are jurisdictional. 

The final rule does not distinguish among natural, modified, and constructed features in the 

definition of “tributary.” The preamble to the final rule, as well as Section VII of the Technical 

Support Document, describe that the scientific literature supports a conclusion that waters 

meeting the definition of “tributary,” either individually or in combination have a significant 

nexus. The final rule therefore indicates that waters that meet the definition of “tributary” and 

are not excluded under paragraph (b), are considered jurisdictional. The rationale for this 

approach is based on the fact that modified and constructed tributaries perform many of the same 

functions as natural tributaries, especially the conveyance of water that carries nutrients, 

pollutants, and other constituents, both good and bad, to traditional navigable waters, interstate 

waters, and the territorial seas.

Section I of the Technical Support Document, discusses the historic scope of the existing 

regulatory definition of “waters of the United States,” and also describes the consistency of the 

final rule with both the statute and judicial decisions, including those of the U.S. Supreme Court. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

21

While paragraph (b) of the final rule provides for the exclusion of many features from 

consideration as waters of the United States, including stormwater control features created in dry 

land and many ditches regardless of use, Section I of the Technical Support Document also 

provides the legal framework under which a ditch could be considered both a point source and a 

water of the United States.

The definition of “tributary” in the final rule no longer includes wetlands, lakes, ponds and 

impoundments as tributaries. However, the definition retains the phrase “contributes flow, either 

directly or through another water.” This reflects scientific literature about the connectivity 

among waters. The final rule’s definition makes clear that a water is considered tributary only if 

(1) it contributes flow, either directly or through another water, to a traditional navigable water, 

interstate water, or the territorial seas, and (2) it has the physical indicators of a bed and banks 

and an OHWM. The term “ordinary high water mark” has been defined in the regulations of the 

U.S. Army Corps of Engineers (Corps) since 1986. It has been used by Corps Districts 

nationwide to determine the lateral limits of jurisdiction over non-tidal water bodies for the 

CWA section 404 permitting program. The final rule does not change the definition of OHWM, 

but simply incorporates it into EPA’s regulations for consistency and clarity. 

Streams with a break in OHWM can be water of the United States under current practice, which 

dictates that a natural or man-made discontinuity in the OHWM does not necessarily sever 

jurisdiction (e.g., where the stream temporarily flows underground, or where the OHWM has 

been removed by development or agricultural practices). The agencies’ position is supported by

science, and the U.S. Environmental Protection Agency Office of Research and Development 

report, “Connectivity of Streams and Wetlands to Downstream Waters,” which discusses how 

breaks in stream channel characteristics change the nature of the connection to downstream 

waters, but do not remove it. 

Section III(C) of the preamble and Section VII of the Technical Support Document discuss the 

science supporting the agencies’ determination that waters meeting the definition of “tributary” 

have a significant nexus because they significantly affect the chemical, physical, and biological 

integrity of traditional navigable waters, interstate waters, and the territorial seas. See also 

Section 9 “Scientific Evidence Supporting the Rule” of the Response to Comments. 

Specific Comments

National Association of State Foresters (Doc. #14636)

8.1 ...[T]he proposed rule’s attempt at categorically defining “all tributaries” as WOTUS 

including man-made ditches, and certain lands adjacent to tributaries such as riparian 

areas and floodplains, would seem to result in a much broader reach of federal 

jurisdiction, regardless of whether or not the tributary has a significant nexus to, or 

relative permanence of, water. We propose that if a new definition of the term tributary is 

necessary, then that new definition needs to be more precise than what is currently 

proposed as “all tributaries.” (p. 2)

Agency Response: See summary essay 8.1 above for response. With respect to 

commenter’s assertion that the proposed definition is an expansion of jurisdiction --

The agencies disagree with the assertion the definition of tributary would expand 
Clean Water Rule Response to Comments – Topic 8: Tributaries

22

jurisdiction. CWA jurisdiction historically has been asserted over intermittent and 

ephemeral waters. As discussed at greater detail in the summary essay for Section 

8.1.1 below, the longstanding regulatory definition of “waters of the United States” 

included “tributaries” without any limitations regarding volume or duration of 

flow. The December 2008 Guidance on post-Rapanos implementation noted that 

tributaries that flow only in direct response to rainfall are subject to the CWA if 

they have a significant nexus to a downstream traditional navigable water, and that 

intermittent or seasonal streams were jurisdictional without the need for a casespecific showing of significant nexus. Regulations addressing water quality 

standards for waters of the United States provide that states may modify standards 

for streams with natural ephemeral flow but may not declare an ephemeral stream 

non-jurisdictional altogether. Federal court decisions, some of which are decades 

old, have supported assertions that intermittent and ephemeral waters are 

jurisdictional. Practice after Rapanos has considered ephemeral waters as 

jurisdictional under the CWA where they have a significant nexus to a traditional 

navigable water. Similarly, longstanding agency practice has asserted jurisdiction 

over certain ditches, and thus agencies do not view the final rule’s approach to 

ditches as an expansion. For more discussion, see Compendium #6 “Ditches.”With 

respect to commenter’s assertion that the definition is not sufficiently precise -- The 

final rule definition provides greater clarity than under previous definitions of 

waters of the United States by providing, for the first time, a definition of 

“tributary.” Previous definitions of waters of the United States regulated all 

tributary streams without qualification because the regulations did not define 

tributary. The final rule defines “tributary” by requiring a bed and banks and an 

OHWM (physical characteristics created by sufficient volume, frequency, and 

duration of flow), and requiring that the water contributes flow, either directly or 

through another water, to a traditional navigable water, interstate water, or the 

territorial seas. The definition clarifies that natural or man-made breaks in bed and 

banks or OHWM do not result in a water losing its tributary status, and that a 

tributary can be natural, man-altered, or man-made. The definition is based on the 

best available science, intent of the CWA, and caselaw, and is consistent with 

current practice. To ensure clarity on issues that public comments and the agencies’ 

implementation experience indicates would be helpful, the final rule definition 

continues to explain the relevance of breaks in OHWMs and man-made and manaltered streams. 

In response to public comments and to further increase clarity, the final rule 

preamble defines perennial, intermittent, and ephemera flows. In addition, the 

preamble includes a definition of bed and banks adapted largely from longstanding 

agencies’ practice as well as public comments. The agencies have added the Corps’ 

existing regulatory definition of “ordinary high water mark” to EPA’s regulations, 

and Corps technical manuals are available to help ensure consistency with how field 

staff identify presence of an OHWM. For more discussion of definitions and their 

impact on overall final rule clarity, see Compendium #14. The final rule also 

provides that wetlands, lakes, and ponds that lack bed, banks, and an ordinary high 

water mark should be evaluated as adjacent waters and not as tributaries. The final 

rule does not provide quantitative measures for tributary, because peer-reviewed 
Clean Water Rule Response to Comments – Topic 8: Tributaries

23

science establishes no flow threshold below which a tributary would not have an 

important effect on the integrity of downstream traditional navigable waters, 

interstate waters, or the territorial seas either alone or in combination with similarly 

situated waters (See Compendium #9, Scientific Evidence Supporting Rule). 

Tennessee Valley Association (Doc. #17470)

8.2 ...With the proposed "tributary" definition, the Agencies have expanded the scope of 

features that are currently regulated as tributaries, extending jurisdiction to features like 

ephemeral drainages and wet-weather conveyances that have not previously been 

categorically jurisdictional.3)

Agency Response: The agencies disagree with the assertion that intermittent and 

ephemeral waters have not been jurisdictional previously. CWA jurisdiction 

historically has been asserted over intermittent and ephemeral waters. The 

longstanding regulatory definition of “waters of the United States” included 

“tributaries” without any limitations regarding volume or duration of flow. The 

December 2008 Guidance on post-Rapanos implementation noted that tributaries 

that flow only in direct response to rainfall are subject to the CWA if they have a 

significant nexus to a downstream traditional navigable water, and that intermittent 

or seasonal streams were jurisdictional without the need for a case-specific showing 

of significant nexus. Regulations addressing water quality standards for waters of 

the United States provide that states may modify standards for streams with natural 

ephemeral flow but may not declare an ephemeral stream non-jurisdictional 

altogether. See, e.g., 40 CFR § 131.10(g)(2). Several states and tribes expressly 

cover intermittent and ephemeral waters in their water quality standards submitted 

to EPA for review under the CWA, including Arizona, Delaware, New Mexico, 

South Carolina, and the Ute Mountain Ute Tribe, among others. Federal court 

decisions, some of which are decades old, have supported assertions that 

intermittent and ephemeral waters are jurisdictional. For example, the U.S. District 

court in Arizona held in 1975 that the definition of waters of the United States 

includes any waterway: “ ... a legal definition of ‘navigable waters’ or ‘waters of 

the United States’ within the scope of the Act includes any waterway within the 

United States also including normally dry arroyos through which water may flow, 

whether such water will ultimately end up in public waters such as a river or 

stream, tributary to a river or stream, lake, reservoir, bay, gulf, sea or ocean either 

within or adjacent to the United States.” United States v. Phelps Dodge Corp, 391 

F.Supp 1181, 1187 (1975). Practice after Rapanos has considered ephemeral waters 

as jurisdictional under the CWA where they have a significant nexus to a traditional 

navigable water. For example, EPA and the Army Corps of Engineers issued a joint 

memorandum in 2007 asserting jurisdiction over a first-order ephemeral stream in 

Riverside County, California, based on its significant nexus to a traditional 

navigable water. “Assertion of Jurisdiction for Jurisdictional Determination SPL2007-261-FBV” (Dec. 6, 2007), available at: 

http://www.usace.army.mil/Missions/CivilWorks/RegulatoryProgramandPermits/R

elatedResources/CWAGuidance.aspx. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

24

8.3 ... the newly proposed definition of tributaries includes waters and features well beyond 

those that have been deemed jurisdictional based on current practice under existing 

guidance from the Agencies. The proposed rule defines "tributary" as "a water physically 

characterized by the presence of a bed and banks and ordinary high water mark ... which 

contributes flow, either directly or through another water" to a TNW, interstate water, 

territorial sea, or impoundment. 79 Fed. Reg. 22,263. In addition, wetlands, lakes, and 

ponds can be treated as tributaries if they contribute flow to a TNW, interstate water, or 

territorial sea, even if they lack a bed, banks, and ordinary high water mark (OHWM). In 

our experience, this represents a major expansion over recent determinations of 

jurisdiction. Also, the Proposal specifically includes "ditches" in the definition of 

tributary, meaning that ditches with a bed, bank, and OHWM that contribute flow will be 

considered jurisdictional unless they meet one of the narrow exclusions. This change 

conflicts with the 2008 Rapanos Guidance which provided that ditches “ are generally not 

waters of the United States...”. We believe that, in spite of the Agencies' stated position, 

the breadth of this definition for tributaries leaves room for regulating a considerable 

number of water features not previously considered to be "waters of the United States," 

including ephemeral drainages, wet weather conveyances, ditches, and streams carrying 

minimal water volumes and which are remote from any navigable-in-fact water. (p. 5)

Agency Response: As discussed in the summary essay above, the agencies do not 

view the proposed or final rule as an expansion. CWA programs have since its 

enactment in 1972 protected the quality within all waters of the United States, and 

not just the downstream navigable waters. As discussed in the preamble, the U.S. 

Supreme Court is in agreement that the term “waters of the United States” 

encompasses waters that are not navigable in the traditional sense. See Technical 

Support Document for more discussion. As discussed in the response immediately 

above, ephemeral and intermittent streams have been considered “waters of the US” 

under longstanding practice. Similarly, longstanding agency practice has asserted 

jurisdiction over certain ditches, and thus do not view the final rule’s approach to 

ditches as an expansion. For example, under previous regulations, the agencies’ 

longstanding practice has been to consider ditches to be tributaries and thus a water 

of the United States where they contributed flow to the tributary system, 

particularly where a ditch had been excavated in a natural stream or relocated a 

natural stream. When the 2008 interagency Rapanos Guidance discussed ditches 

that were not jurisdictional, the guidance identified non-jurisdictional ditches as 

those ditches (including roadside ditches) excavated wholly in and draining only 

uplands and that did not carry a relatively permanent flow of water. The final rule 

has expanded this exclusion for ditches encompass ephemeral ditches that are not a 

relocated tributary or excavated in a tributary, intermittent ditches that are not a 

relocated tributary, excavated in a tributary, or drain wetlands, and ditches that do 

not flow, either directly or through another water, into a traditional navigable 

water, interstate water, or territorial sea. As a result, not only is the final rule not 

an expansion because it regulates certain ditches, it regulates fewer ditches than 

under current practice. For more discussion, see Compendium #6 “Ditches.” With 

respect to regulation of ditches and wet weather conveyances, it is not the intent of 

the agencies to regulate new types of waters that were not historically regulated. As 

a result, the final rule includes an explicit exclusion from the definition of water of 
Clean Water Rule Response to Comments – Topic 8: Tributaries

25

the United States for stormwater control features constructed to convey, treat, or 

store stormwater that are created in dry land ((b)(6)). This exclusion is discussed 

further in Compendium #7, “Features and Waters Not Jurisdictional.” The CWA 

does not regulate lands as “waters of the United States.” The proposal’s reference 

to riparian areas and floodplains in the definition of “neighboring” adjacent waters 

was to waters in the riparian area or floodplain, and did not seek to regulate lands 

in those areas. The definition of “neighboring” has been revised in response to 

comments received to clarify this and related points. For more information, see 

Compendium #3, “Adjacent Waters,” particularly subsection 3.2 on the definition of 

neighboring. For more discussion on OHWM, see the summary essays and 

individual responses below in this compendium.

Bullhead City, Arizona (Doc. #4185)

8.4 ...EPA also proposes to include "natural, man-altered, or man-made" in the new 

definition of tributary, appearing that the EPA is basing its categorical classification of 

tributaries as "waters of the U.S.", regardless of their size, amount of flow and distance 

from a traditional navigable water, on the significant nexus test articulated by Justice 

Kennedy in his concurring opinion in Rapanos v. United States, 547 U.S. 715 (2006), 

which was meant to be applied in a site-specific analysis; ... (p. 1)

Agency Response: See summary response for section 8.1. Section III of the 

preamble to the final rule and section II of the Technical Support Document 

describes the agencies’ significant nexus analysis.

Pennsylvania Fish and Boat Commission (Doc. #4826)

8.5 From a state resource agency's perspective, the PFBC interprets most of the proposed rule 

as straight forward, however the "tributaries" and "other waters" components of the rule 

appear to be the most challenging to achieve consistency on a nationwide basis. The 

PFBC firmly lauds the facts from scientific peer reviewed literature that reveal the 

importance of tributaries and the ecological importance of maintaining the biological, 

physical, and chemical integrity to the downstream watershed. The PFBC has in fact, 

recognized the value of tributaries and has included in agency policy the following 

provision regarding tributaries within Pennsylvania Code Title 58 Recreation§ 57.11 

Statements of Policy, Listing of wild trout streams. (4) Tributary linkages. Tributaries of 

wild trout streams are classified as wild trout stream for their function as habitat for 

segments of wild trout populations, including nurseries and refuges, and in sustaining 

water quality necessary for wild trout. This language provides protection for a specific 

fish community based on maintenance of the physical, and chemical quality of tributaries 

in a watershed that supports a cold water fish community. The PFBC suggests this policy 

language is analogous in intent and in support of language defining tributaries and their 

functions in the proposed "waters of the United States" definition. (p. 2)

Agency Response: The agencies agree with the commenter that peer-reviewed 

scientific literature, including that discussing aquatic biota such as fish, support the 

approach in the proposed and final rules. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

26

Quapaw Tribe of Oklahoma (the O-Gah-Pah) (Doc. #7980)

8.6 2. Definition of Tributary. Existing regulations do not define this term. In practice, the 

term is usually restricted to active channels with ordinary high water marks that connect 

(either directly or through downstream channels) to a traditional navigable water. Under 

the proposed rule, a tributary would be defined to include natural and manmade water 

bodies with ordinary high water marks (regardless of flow regime), in addition to 

wetlands and other waters that do not have ordinary high water marks, provided that the 

water feature contributes flow (directly or indirectly) to a traditional navigable water. 

Features that would otherwise meet the definition of tributary do not lose that status if, 

for any length, there are natural or manmade breaks, provided that there is an ordinary 

high water mark upstream of the break. The proposed rule's definition of tributaries 

would add a large number of previously unregulated features to those considered 

tributaries to traditional navigable waters, and thus by rule, are Waters of the U.S.

(p. 2)

Agency Response: See the section on OHWM below in this compendium for 

discussion and responses to comments on OHWM. With respect to waters being 

newly regulated, the agencies disagree with the assertion that many types of 

previously unregulated waters would be jurisdictional as tributaries. Longstanding 

agency practice has asserted jurisdiction over certain ditches, and thus do not view 

the final rule’s approach to ditches as an expansion. For example, under previous 

regulations, the agencies’ longstanding practice has been to consider ditches to be 

tributaries and thus a water of the United States where they contributed flow to the 

tributary system, particularly where a ditch had been excavated in a natural stream 

or relocated a natural stream. When the 2008 interagency Rapanos Guidance 

discussed ditches that were not jurisdictional, the guidance identified nonjurisdictional ditches as those ditches (including roadside ditches) excavated wholly 

in and draining only uplands and that did not carry a relatively permanent flow of 

water. The final rule has expanded this exclusion for ditches encompass ephemeral 

ditches that are not a relocated tributary or excavated in a tributary, intermittent 

ditches that are not a relocated tributary, excavated in a tributary, or drain 

wetlands, and ditches that do not flow, either directly or through another water, into 

a traditional navigable water, interstate water, or territorial sea. As a result, not 

only is the final rule not an expansion because it regulates certain ditches, it 

regulates fewer ditches than under current practice. For more discussion, see 

Compendium #6 “Ditches.” Similarly, CWA jurisdiction historically has been 

asserted over intermittent and ephemeral waters. The longstanding regulatory 

definition of “waters of the United States” included “tributaries” without any 

limitations regarding volume or duration of flow. The December 2008 Guidance on 

post-Rapanos implementation noted that tributaries that flow only in direct 

response to rainfall are subject to the CWA if they have a significant nexus to a 

downstream traditional navigable water, and that intermittent or seasonal streams 

were jurisdictional without the need for a case-specific showing of significant nexus. 

Regulations addressing water quality standards for waters of the United States 

provide that states may modify standards for streams with natural ephemeral flow 

but may not declare an ephemeral stream non-jurisdictional altogether. See, e.g., 40 

CFR § 131.10(g)(2). Several states and tribes expressly cover intermittent and 
Clean Water Rule Response to Comments – Topic 8: Tributaries

27

ephemeral waters in their water quality standards submitted to EPA for review 

under the CWA, including Arizona, Delaware, New Mexico, South Carolina, and 

the Ute Mountain Ute Tribe, among others. Federal court decisions, some of which 

are decades old, have supported assertions that intermittent and ephemeral waters 

are jurisdictional. For example, the U.S. District court in Arizona held in 1975 that 

the definition of waters of the United States includes any waterway: “ ... a legal 

definition of ‘navigable waters’ or ‘waters of the United States’ within the scope of 

the Act includes any waterway within the United States also including normally dry 

arroyos through which water may flow, whether such water will ultimately end up 

in public waters such as a river or stream, tributary to a river or stream, lake, 

reservoir, bay, gulf, sea or ocean either within or adjacent to the United States.” 

United States v. Phelps Dodge Corp, 391 F.Supp 1181, 1187 (1975). Practice after 

Rapanos has considered ephemeral waters as jurisdictional under the CWA where 

they have a significant nexus to a traditional navigable water. For example, EPA 

and the Army Corps of Engineers issued a joint memorandum in 2007 asserting 

jurisdiction over a first-order ephemeral stream in Riverside County, California, 

based on its significant nexus to a traditional navigable water. “Assertion of 

Jurisdiction for Jurisdictional Determination SPL-2007-261-FBV” (Dec. 6, 2007), 

available at: 

http://www.usace.army.mil/Missions/CivilWorks/RegulatoryProgramandPermits/R

elatedResources/CWAGuidance.aspxType here

Pennsylvania Department of Environmental Protection, Office of Water Management (Doc. 

#7985)

8.7 Tributary - Define to mean a channel or conveyance of surface water having both defined 

bed and banks, whether natural or artificial, with perennial or intermittent flow that flows 

to a larger stream or other body of water; the "bed" being the bottom/substrate area/base 

of the channel or conveyance; and "banks" being the break in slope between the edge of 

the bed of the channel and the surrounding terrain and generally parallel to the channel or 

conveyance. (p. 6-7)

Agency Response: See summary response for section 8.1. The preamble to the 

final rule indicates “for purposes of the rule, ‘bed and banks’ means the substrate 

and sides of a channel between which flow is confined. The banks constitute a break 

in slope between the edge of the bed and the surrounding terrain, and may vary 

from steep to gradual.” 

Barona Band of Mission Indians (Doc. #10966)

8.8 -The final rule Section 328(c)(5) defines "tributary" expansively...

Taken literally, this standard would define most of the land area of the United States as 

"waters of the United States." Much rain that falls is not immediately absorbed into the 

ground, and, instead, runs off and is collected through ever-increasing courses, from 

trickles, to runnels, to rivulets, to gullies, to rills, to brooklets, to streamlets, to brooks, to 

creeks, to streams, and to rivers that empty into the ocean. During and after rains, such 

flows, even if only occasional, all drain into the ocean and other indisputably 

jurisdictional waters, from the smallest drainage feature to the largest, through a network 
Clean Water Rule Response to Comments – Topic 8: Tributaries

28

of can include tributaries of tributaries of tributaries, etc. Each of these drainage features, 

from the smallest to the largest, from the most occasional and with ephemeral to the most 

massive and continuous, contributes to the flow of water into some navigable water or 

ocean Presumably, a drop of rain falling on the west edge of the continental divide in 

Colorado that is not absorbed or diverted will eventually find its way into the Colorado 

River and thence into the Pacific Ocean. Presumably, that drop could also carry a 

molecule of a pollutant, a grain of sediment, etc. from the continental divide into the 

Pacific Ocean. While the effect of that single drop on interstate commerce may be de 

mnimis, the Tribe will assume that the cumulative effects of many such drops may be 

aggregated to produce a significant effect.

That single drop of water, along with others like it, will have a cumulative significant 

effect on the physical, biological, and chemical integrity of the indisputably jurisdictional 

waters into which they eventually flow. The EPA is correct in this conclusion. See 79 

F.R. at p. 22206. But the mere fact that such a cumulative effect may exist does not, in 

itself, justify the regulation of that drop of water from the very first point, near the 

continental divide, where it first enters the most evanescent, ephemeral, and tiny drainage 

with a bed, banks, and OHWM, especially if that confluence of characteristics 

immediately ceases and does not reappear for many miles. If this conclusion did follow, 

then virtually the entire land mass of the United States would become "waters of the 

United States". At some point, virtually every drop of rain that is not absorbed or diverted 

will enter something that qualifies as a "tributary". From that point onward, even if there 

is a no further confluence of bed, banks, and OHWM for any indefinite distance, the land 

over which that drop passes on its way to the sea will be "waters of the United States", 

thereby expanding the jurisdiction of the EPA and ACE under the Clean Water Act from 

not just "waters of the United States" to "lands of the United States". (p. 2-3)

Agency Response: See summary responses for sections 8.1 and 8.4. Section I of 

the Technical Support Document describes the legal basis of the final rule and also 

provides a review of the historic scope of the regulatory definition of “waters of the 

United States.”

8.9 C. The Tribe suggests a paradigm for a more practical definition of "tributary".

Another major provision of the CWA deals with regulation of pollutants from "point 

sources." All sources of such pollutants must be either point sources or non-point sources, 

but only "point source" is defined. A "point source" is

any discernable, confined and discrete conveyance, including but not limited to 

any pipe, ditch, channel, tunnel, conduit, well, discrete fissure, container, rolling 

stock, concentrated animal feeding operation, or vessel or other floating craft, 

from which pollutants are or may be discharged. [33 U.S.C. §1362(14)]

There is no definition for non-point source, largely because, by its nature, it is so diffuse 

as to defy useful definition:

Stormwater that is not collected or channeled and then discharged, but rather runs 

off and dissipates in a natural and unimpeded manner, is not a discharge from a 

point source as defined by §502(14). As we wrote in League of Wilderness 
Clean Water Rule Response to Comments – Topic 8: Tributaries

29

Defenders/Blue Mountains Biodiversity Project v. Forsgren, 309 F.3d 1881, 1884 

(9th Cir., 2002):

Although nonpoint source pollution is not statutorily defined, it is widely 

understood to be the type of pollution that arises from many dispersed 

activities over large areas, and is not traceable to any single discrete 

source. Because it arises in such a diffuse way, it is very difficult to 

regulate through individual permits.

Northwest Environmental Defense Center v. Brown, 640 F.3d 1063, 1070 

(9th Cir., 2011)

Point sources and non-point sources are thus the two ends of a spectrum of discharges 

that, at some intermediate point, switches from one to the other. In this way, they are 

similar to the water spectrum of trickle, rivulet, fill, gully, brooklet, streamlet, brook, 

creek, stream, river, and ocean. As the Ninth Circuit has recently noted in this regard,

However, when stormwater runoff is collected in a system of ditches, culverts, and 

channels and then is discharged into a stream or river, there is a "discernable, confined 

and concrete conveyance" of pollutants, and there is therefore a discharge from a point 

source. In other words, runoff is not inherently a nonpoint or point source of pollution. 

Rather, it is a nonpoint or point source under §502(14) depending on whether it is 

allowed to run off naturally (and is thus a nonpoint) or is collected, channeled, and 

discharged through a system of ditches, channels, culverts, and similar conveyances (and 

is thus a point source discharge).

Id

The point of inflexion of the pollutant source spectrum is the point at which runoff 

becomes confined into a ditch, channel, culvert, or similar structure and is thus 

segregated from natural free-ranging flow. The proposed rule sets this point of inflexion 

for water courses at the point where a rill or gully first acquires an OHWM and either a 

bed or a bank. The impracticality of and Constitutional problems with this definition are 

noted above. Instead, The Tribe suggests that the EPA replace this proposed point of 

inflexion for the water course spectrum to be a point that can be identified by objective 

and measurable factors (e.g., volume of flow, duration of flow, time of year of flow, 

likelihood of and capacity for carrying a significant quantity of pollutants, actual quantity 

and of pollutants and/or sediment, seasonality, distance to a navigable water, etc.). A 

point of inflexion with objective criteria is (1) far easier to administer, (2) much less 

likely to generate legal challenges, (3) predictable for the benefit of the regulated public, 

and (4) not presenting the kinds of constitutional issues that the current proposal raises. 

The Tribe will leave it to the EPA to consider this suggestion, in the hope that the above 

advantages will induce it to abandon a definition of "tributary" that needlessly causes the 

problems noted above, in favor of one that equally serves the purposes of the CWA 

without endlessly prolonging the conflicts engendered by Rapanos. (p. 8-9)

Agency Response: See summary response for section 8.1. Section I of the 

Technical Support Document provides the legal framework under which a ditch 

could be considered both a point source and a water of the United States. 

Paragraph (b) of the final rule excludes many features, including most ditches that 
Clean Water Rule Response to Comments – Topic 8: Tributaries

30

are not relocated tributaries or excavated in tributaries. See section IV(I) of the 

preamble to the final rule and summary responses in Compendium #7 “Features 

and Waters Not Jurisdictional,” for a broad discussion of the final rule’s exclusions.

Department of Justice, State of Montana (Doc. #13625)

8.10 While this discussion was about tributaries and adjacent wetlands, it indicates a 

regulation must contain specific criteria that allow objective identification of 

jurisdictional waters. But in your agencies' proposal, the definitions of "neighboring," 

"riparian area," "floodplain," and "significant nexus," lack any such specific limiting or 

defining criteria as to volume off low, proximity to navigable waters, or any other 

parameter. The only definition containing such criteria is the definition of "tributary," in 

its reference to bed, banks and ordinary high water mark, but after naming those, the 

definition quickly departs from any objectively identifiable criteria when it says: "In 

addition, wetlands, lakes, and ponds are tributaries (even if they lack a bed and banks or 

ordinary high water mark) if they contribute flow, either directly or through another water 

to a water identified in paragraphs (a)(l) though (3) of this definition." (p. 3)

Agency Response: See summary response for section 8.1.

Illinois Farm Bureau (Doc. #14070)

8.11 In their WOTUS proposal, EPA and the Corps have defined for the first time what they 

consider to be a “tributary.” Making all ephemeral and intermittent tributaries 

jurisdictional is simply extraordinary. In practice, relying on the plain English meanings 

of the proposed rule, literally millions of drainage features in every part of every farming 

region of the country will have characteristics – a bed, bank and ordinary high water 

mark – that would make them tributaries. This will expand the jurisdiction of EPA and 

the Corps in an unprecedented manner that conflicts with both the clear direction and 

intent of the Supreme Court’s prior numerous decisions that sought to limit the federal 

jurisdiction over private lands.

One of EPA’s and the Corps’ expressly stated goals for the proposed rule was to create 

certainty for the regulated community. In fact and in practice, for farmers, the exact 

opposite will occur. As proposed, the drainage features that exist in farm fields in nearly 

every farming region in the country, many with visible channels, beds, banks and high 

water marks, all appear to be WOTUS. Whether they are or are not WOTUS will depend 

on the outcome of a formal determination, a process and status that will be a source of 

unprecedented uncertainty for farmers. Not only is there uncertainty created by the 

definition of tributary as it might be interpeted in the field, every farmer knows that field 

judgments will have their own uncertain outcome, depending on the subjective and 

different judgment calls made by different agency personnel. (p. 2)

Agency Response: See summary response for section 8.1. Paragraph (b) of the 

final rule excludes many features of concern to the agriculture community. Such 

exclusions include prior converted cropland, most ditches that are not relocated 

tributaries or excavated in tributaries, artificially irrigated areas that would revert 

to dry land should application of water to that area cease, artificial lakes and ponds 

created in dry land and used primarily for such uses as stock watering or irrigation, 

and erosional features that do not meet the definition of “tributary” in the final rule. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

31

Paragraph (b) also makes it clear that the features identified therein “are not waters 

of the United States even where they otherwise meet the terms of paragraphs (a)(1) 

through (a)(8)” of the rule. Thus, any feature excluded under paragraph (b) may 

not be considered waters of the United States under any other provision of the rule. 

Additionally, all statutory exemptions, including those exempting normal farming, 

silviculture and ranching activities from CWA section 404 permitting, remain in 

effect and unchanged by the final rule.

North Carolina Department of Agriculture and Consumer Services (Doc. #14747)

8.12 As currently drafted, the proposed rule raises legitimate concerns about the regulation of 

on farm ephemeral streams, ditches, ponds, and isolated wetlands. NCDA&CS opposes 

the new definition of tributaries as it encompasses far more waters than intended under 

the CWA and Supreme Court decisions, including ditches and ephemeral streams. If a 

definition of tributary is included in the final rule, this definition should be revised to 

include fewer waters. (p. 2)

Agency Response: See summary response for section 8.1. Paragraph (b) of the 

final rule excludes many features of concern to the agriculture community. Such 

exclusions include prior converted cropland, most ditches that are not relocated 

tributaries or excavated in tributaries, artificially irrigated areas that would revert 

to dry land should application of water to that area cease, artificial lakes and ponds 

created in dry land and used primarily for such uses as stock watering or irrigation, 

and erosional features that do not meet the definition of “tributary” in the final rule. 

Paragraph (b) also makes it clear that the features identified therein “are not waters 

of the United States even where they otherwise meet the terms of paragraphs (a)(1) 

through (a)(8)” of the rule. Thus, any feature excluded under paragraph (b) may 

not be considered waters of the United States under any other provision of the rule. 

Additionally, all statutory exemptions, including those exempting normal farming, 

silviculture and ranching activities from CWA section 404 permitting, remain in 

effect and unchanged by the final rule.

San Carlos Apache Tribe (Doc. #15067)

8.13 Existing regulations do not define tributary. In practice, the term is usually restricted to 

active channels with ordinary high water marks that connect (either directly or through 

downstream channels) to traditional navigable waters. Under the proposed rule, a 

tributary would be defined to include natural and manmade water bodies with banks and 

beds and high water marks (regardless of flow regime), in addition to wetlands and other 

waters that do not have ordinary high water marks (“OHWM”), provided that the water 

feature contributes flow (directly or indirectly) to a traditional navigable water.

Presumably, a drop of rain falling on the west edge of the continental divide that is not 

absorbed or diverted will eventually find its way into the Pacific Ocean. Presumably, that 

drop could also carry a molecule of a pollutant from the continental divide into the 

Pacific Ocean. Thus, any single drop of water may have a cumulative effect on the 

physical, biological, and chemical integrity of jurisdictional waters into which they 

eventually flow. The EPA is correct in this conclusion. See 79 F.R. at p. 22206. The mere 

fact that such a cumulative effect may exist does not, in itself, justify the regulation of 
Clean Water Rule Response to Comments – Topic 8: Tributaries

32

every drop of water that may ultimately flow into a jurisdictional water. At some point, 

virtually every drop of rain that is not absorbed or diverted will enter something that 

qualifies as a “tributary” under the proposed rule. (p. 4)

Agency Response: See summary response for section 8.1. Section I of the 

Technical Support Document describes the legal basis of the final rule and also 

provides a review of the historic scope of the regulatory definition of “waters of the 

United States.”

Florida Department of Environmental Protection (Doc. #15080)

8.14 ...Size, flow frequency, flow rate, and distance from the nearest core federal water do not 

appear to be relevant inquiries when determining the jurisdictional status of tributaries. 

79 Fed. Reg. at 22,206. 

 The Department asks that the federal agencies clarify whether size, flow 

frequency, flow rate, and distance are relevant factors when assessing the degree 

of connectivity between individual water bodies. If so, is there opportunity to 

refine the jurisdictional category to account for variability in these factors? (p. 4)

Agency Response: Section III of the preamble to the final rule and section II of 

the Technical Support Document describes the agencies’ significant nexus analysis. 

Tennessee Department of Environment and Conservation (Doc. #15135)

8.15 The SAB review of the proposed rule includes:

Tributaries, as a group, exert strong influence on the physical, chemical, biological 

integrity of downstream waters, even though the degree of connectivity is a function of 

variation in the frequency, duration, magnitude, predictability, and consequences of 

physical, chemical and biological processes. SAB advises EPA to reconsider the 

definition of tributaries because not all tributaries have ordinary high water marks- they 

may be absent in ephemeral streams within arid and semi-arid environments or low 

gradient landscapes where the flow of waters is unlikely to cause an ordinary high water 

mark. SAB advises EPA to consider changing the wording to "bed, bank and other 

evidence of flow."

Comment: The state agencies have concerns regarding EPA's broad tributary definition, 

specifically in the ephemeral context that will be discussed in detail below. Our 

experience is that there is already inconsistent distinction between erosional features or 

wet weather conveyances and actual streams in the field. Removing the requirement for 

an ordinary high water mark, when such a mark may be one of the driving characteristics 

that could demonstrate connectivity (and the effects that may follow) is not insubstantial 

or speculative would clearly call into question whether the legal test for jurisdiction 

would be satisfied. Whether the use of aggregated connectivity to demonstrate the 

required legal nexus is appropriate is also unclear. In science, any flow and any 

connection may be enough for connection, influence and impact, but that is not the end of 

the inquiry for federal jurisdiction. The law requires the nexus to be significant. (p. 12)

Agency Response: See summary response for section 8.1., 8.1.1 and 8.1.2. See also 

Section 9 “Scientific Evidence Supporting the Rule” of the Response to Comments.
Clean Water Rule Response to Comments – Topic 8: Tributaries

33

8.16 With regard to the definition of tributary, and within the context described above 

whereby at least one Corps district is asserting federal jurisdiction over erosional features 

and/or wet weather conveyances, we are skeptical that all features with any evidence a 

federal agency deems adequate of a bed, bank and ordinary high water mark that 

contributes flow in any manner to any down gradient water that eventually reaches a 

traditionally jurisdictional water are appropriately jurisdictional under the CWA within 

the confines the law places on that jurisdiction. Again, the state agencies do not debate 

the federal jurisdiction with regard to the vast majority of the tributary network to 

traditionally navigable water bodies. However, we are concerned with the assertion of 

federal jurisdiction over waters and features that have not historically been federal waters 

in Tennessee and should not become such due to this federal rule proposal. These waters 

and features are either significantly remote in geographic distance from traditionally 

navigable waters and/or erosional in nature and should not get absorbed in the reach of 

federal jurisdiction through the broad definition of tributary and its categorical 

application. The state agencies recommend EPA and the Corps revise the definition of 

tributary to include qualifying language making it clear that erosional features should 

not be considered tributaries and provide some minimum threshold for the amount of 

flow that must be present and/or the amount of time water must be present with in the 

water body. (p. 21)

Agency Response: See summary response for section 8.1. Section I of the 

Technical Support Document describes the legal basis of the final rule. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

determination that waters meeting the definition of “tributary” in the final rule 

have a significant nexus because they significantly affect the chemical, physical, and 

biological integrity of traditional navigable waters, interstate waters, and the 

territorial seas. Paragraph (b) of the final rule excludes many features, including 

non-wetland swales and most ditches that are not relocated tributaries or excavated 

in tributaries. See section IV(I) of the preamble to the final rule and summary 

responses in Compendium 7 “Features and Waters Not Jurisdictional,” for a broad 

discussion of the final rule’s exclusions. See summary responses for section 6.0, 

“Ditches,” and 6.2, “Excluded Ditches,” in this RTC for a focused description of 

how the exclusions for ditches were revised and clarified for the final rule.

Wisconsin Department of Natural Resource (Doc. #15141)

8.17 The definition of tributary includes waters that have a defined bed and banks and an 

ordinary high water mark and contributes flow directly or through another water to a 

traditional WOTUS. The definition goes on to say that wetlands, lakes and ponds do not 

need to have a bed, banks or OHWM to fall within the definition of tributary as long as it 

contributes flow directly or through another water to a traditional WOTUS. The rule is 

unclear and it should be clarified whether a tributary that contributes flow through 

another water must also have a bed and bank and OHWM.

Although the proposed definition includes waters, such as wetlands, lakes and ponds that do 

not have a bed and banks or an ordinary high water mark but contribute flow to traditional 

waters, the definition would not include tributaries, such as head water streams, that may not 

exhibit a bed and banks or ordinary high water mark. Although these waters may be 
Clean Water Rule Response to Comments – Topic 8: Tributaries

34

regulated as "adjacent waters" it seems counterintuitive to regulate some waters, which do 

not exhibit a bed and banks and OHWM, but not others. The WI DNR suggests the agencies 

make a determination on the proposed regulatory construct, so that comments that are 

provided can be responsive to the proposal. Additionally, we would recommend the proposed 

regulations not result in any increase of jurisdiction over current federal guidance. (p. 2)

Agency Response: See summary response for section 8.1.

California State Water Resources Control Board (Doc. #15213)

8.18 We also strongly support the Agencies' science -based approach to the rulemaking, 

particularly with respect to further defining the types of water bodies that are considered 

to be "waters of the United States" because they significantly affect the chemical, 

physical, or biological integrity of traditional navigable waters, interstate waters, or the 

territorial seas.

For example, the inclusion of all tributaries (including headwaters, ephemeral and 

intermittent streams, and tributary wetlands and ponds) as jurisdictional waters is an 

important step in protecting water quality in California. Both the Agencies' peer- reviewed 

scientific report and the Science Advisory Board's October 17, 2014 review of the Agencies' 

report correctly recognize the importance of all tributaries in maintaining the biological, 

physical, and chemical integrity of downstream waters. As shown in Attachment A of this 

letter, intermittent and ephemeral streams cover a significant portion of California's surface 

area. As recommended by the Science Advisory Board in its September 30, 2014 letter to the 

Agencies, however, the Agencies should consider whether the proposed definition of 

"tributary" actually includes all ephemeral streams as intended, but also clearly distinguishes 

such tributaries from excluded non -tributary ditches. In addition, natural discontinuous 

channels in dry land stream systems should also be considered to be tributaries, even when 

there are one or more natural breaks in the channel. (p. 1-2)

Agency Response: See summary response for section 8.1.

8.19 The following specific comments are provided by the California State Water Resources 

Control Board and the nine California regional water quality control boards (collectively, 

the "Water Boards ") staff regarding the proposed "Definition of 'Waters of the United 

States' Under the Clean Water Act" (Proposed Rule) for 40 CFR 230.3. Specific 

recommended changes to the proposed regulations are shown in strikeout/underline 

format. Additional comments are presented as endnotes.

...

(5) Tributary. The term tributary means a water physically characterized by the presence 

of a bed and banks and ordinary high water mark, as defined at 33 CFR 328.3(e), which 

contributes flow, either directly or through another water, to a water identified in 

paragraphs (s)(1) through (4) of this section. In addition, wetlands,[9] lakes, and ponds 

are tributaries (even if they lack a bed and banks or ordinary high water mark) if they 

contribute flow, either directly or through another water to a water identified in 

paragraphs (s)(1) through (3) of this section. A water that otherwise qualifies as a 

tributary under this definition does not lose its status as a tributary if, for any length, there 

are one or more man -made breaks (such as bridges, culverts, pipes, or dams), or one or 

more natural breaks (such as wetlands at the head of or along the run of a stream, natural 
Clean Water Rule Response to Comments – Topic 8: Tributaries

35

discontinuous channels in dryland stream systems,[10] debris piles, boulder fields, or a 

stream that flows underground) so long as a bed and banks and an ordinary high water 

mark can be identified upstream of the break. A tributary, including wetlands, can be a 

natural, man -altered, or man -made water and includes waters such as rivers, streams, 

lakes, ponds, impoundments, canals, and ditches not excluded in paragraph (t)(3) or (4) 

of this section. (6) Wetlands. The term wetlands means those areas that are inundated or 

saturated by surface or groundwater 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. 

...

[Endnotes]

[9] We support the proposed language including wetlands as tributary. However, the 

Agencies should consider whether interconnecting non -wetland swales that provide 

critical hydrologic connectivity to wetland complexes should be excluded. In California,

this is commonly found in vernal pool complexes. Although vernal pools may be 

considered jurisdictional, swales that provide chemical, physical, and biological 

connectivity would be excluded. For clarity, we suggest that the Agencies consider 

whether to add "interconnecting swales" to clarify that interconnecting swales in wetland 

complexes should be considered jurisdictional because they directly contribute flows and 

function as part of the tributary system to waters of the United States.

We agree that gullies and rills, and non -wetland swales in upland areas that are purely 

erosional features and do not contribute flow, either directly or through another water, to 

waters of the United States correctly should not be considered jurisdictional by rule. 

However, as suggested by the Scientific Advisory Board, the Agencies should consider 

whether non -wetland swales in arid and semi -arid environments and low gradient 

landscapes should be included as tributaries if they contribute flow to waters of the 

United States (particularly headwaters in zero order basins), regardless of the presence of 

an ordinary high water mark. There are many ephemeral and intermittent tributaries in the 

arid West, such as those ephemeral channels that are tributary to the Mojave River and 

Amargosa River in California. As shown on the National Hydrography Dataset (NHD) 

high resolution map (Attachment A), the majority of streams in California (79 percent) 

are intermittent or ephemeral (INDUS Corporation, 2013).

Headwaters undergo geomorphic processes, such as erosion and incision, which may take 

the initial form of non -wetland swales. Therefore, these headwater features can 

significantly affect the chemical, physical, and biological integrity of waters of the United 

States. The importance of headwater stream systems is noted throughout the preamble to 

the Proposed Rule on page 22201: "The great majority of tributaries are headwater 

streams, and whether they are perennial, intermittent, or ephemeral, they play an 

important role in the transport of water, sediments, organic matter, nutrients, and 

organisms to downstream environments. Tributaries serve to store water, thereby 

reducing flooding, provide biogeochemical functions that help maintain water quality, 

trap and transport sediments, transport, store and modify pollutants, provide habitat for 

plants and animals, and sustain the biological productivity of downstream rivers, lakes 
Clean Water Rule Response to Comments – Topic 8: Tributaries

36

and estuaries." Additionally, the preamble to the Proposed Rule clearly recognizes on 

page 22206 the benefits of headwater and ephemeral streams: "[t]ributaries that are small, 

flow infrequently, or are a substantial distance from the nearest (a)(1) through (a)(3) 

water (e.g., headwater perennial, intermittent, and ephemeral tributaries) are essential 

components of the tributary network and have important effects on the chemical, 

physical, and biological integrity of (a)(1) through (a)(3) waters, contributing many of the 

same functions downstream as larger streams. When their functional contributions to the 

chemical, physical, and biological conditions of downstream waters are considered at a 

watershed scale, the scientific evidence supports a legal determination that they meet the 

"significant nexus" standard articulated by Justice Kennedy in Rapanos."

[10] We note that there are ephemeral and intermittent streams in arid and semi -arid 

regions that are commonly referred to as "drylands" (Levick et al., 2008; CDFG, 2010). 

Natural discontinuous channels in dryland stream ephemeral channels are characterized 

by alternating erosional and depositional reaches that may vary in length (USACE, 2008). 

These channels are constantly in flux and are characterized by temporal and spatial 

changes in channel morphology for any given location. These systems are subject to 

prolonged wet and dry cycles and typically have many years of discontinuous flows. 

Since jurisdiction should be based on physical structure rather than the vagaries of 

climate, these features when contributing flow either directly or through another water to 

a water of the United States, should be considered jurisdictional. (p. 5, 6-7, 8-9)

Agency Response: See summary responses for sections 8.1, 8.1.1 and 8.4. Section 

IV(H) of the preamble to the final rule and section IX of the Technical Support 

Document address “Case-Specific Waters of the United States,” including western 

vernal pools in California.

Sealaska Corporation (Doc. #15356)

8.20 ...the Agencies’ proposal to categorically regulate all “tributaries” would extend to 

intermittent and ephemeral streams, and most ditches. Such an expansive and unilateral 

claim of jurisdiction over tributaries is inconsistent with the plain language of the CWA, 

the Supreme Court’s interpretations of the Act, and the evidence in the administrative 

record. Further as stated above the Connectivity report does not explain how waters, in 

this case tributaries, and wetland systems that may be hydrologically connected 

demonstrate significant nexus. In the coastal temperate rainforest snowmelt and rainfall 

create temporary overland flows, shallow perched areas that create isolated pockets of 

standing water until they evaporate or drain.

Rather than automatically regulating most or all water bodies with a bed and a bank, the 

Agencies should adopt the approach described in Justice Scalia’s plurality opinion in

Rapanos. 

Regardless of whether or not the plurality opinion represents the holding of Rapanos, that 

opinion is most consistent with the Supreme Court’s historic treatment of non-wetland 

areas such as streams. As noted above, Rapanos and Riverside Bayview concerned the 

unique question of whether wetlands, which are “inseparably bound up” with adjacent 

water bodies, are jurisdictional. Their holdings did not address non-wetland water bodies 

such as ponds, natural streams and manmade ditches. SWANCC, by contrast, addressed 
Clean Water Rule Response to Comments – Topic 8: Tributaries

37

the question of whether an isolated pond was jurisdictional. The Court’s clear answer was 

that such ponds were not jurisdictional because the CWA was not intended to regulate 

“nonnavigable, isolated, intrastate waters.”

Consistent with SWANCC’s limited view of CWA jurisdiction over non-wetland water 

bodies, the plurality opinion in Rapanos limited jurisdiction to “those relatively 

permanent, standing or continuously flowing bodies of water ‘forming geographic 

features’ that are described in ordinary parlance as ‘streams,’ ‘oceans, rivers, [and] 

lakes.’” The Rapanos plurality further held that CWA jurisdiction does not include 

channels through which water flows intermittently or ephemerally, or channels that 

periodically provide drainage for rainfall. The plurality opinion also indicated that the 

Agencies’ attempt to regulate manmade water bodies as tributaries is not supported by 

the CWA:

In applying the definition to “ephemeral streams,” “wet meadows,” storm sewers 

and culverts, “directional sheet flow during storm events,” drain tiles, man-made 

drainage ditches, and dry arroyos in the middle of the desert, the Corps has 

stretched the term “waters of the United States” beyond parody. The plain 

language of the statute simply does not authorize this “Land Is Waters” approach 

to federal jurisdiction.1

The Agencies should revise the proposed rule to define jurisdiction over tributaries 

consistent with the Rapanos plurality. Under the plurality’s approach, the Agencies 

would define a tributary as a water that contributes direct flow to a traditional navigable 

water via a continuous surface connection. The plurality’s approach is consistent with the 

plain language of the CWA and its policy to preserve States’ authority over land and 

water use. It is also consistent with SWANCC. The plurality opinion provides a clear, 

defensible basis for the Agencies to draw bright lines including certain types of water 

bodies within CWA jurisdiction and excluding other types of water bodies. (p. 12-13)

Agency Response: See summary response for section 8.1. Section I of the 

Technical Support Document describes the legal basis of the final rule. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

determination that waters meeting the definition of “tributary” in the final rule 

have a significant nexus because they significantly affect the chemical, physical, and 

biological integrity of traditional navigable waters, interstate waters, and the 

territorial seas. Paragraph (b) of the final rule excludes many features, including 

most ditches that are not relocated tributaries or excavated in tributaries. See 

section IV(I) of the preamble to the final rule and summary responses in 

Compendium 7 “Features and Waters Not Jurisdictional,” for a broad discussion of 

the final rule’s exclusions. See summary responses for section 6.0, “Ditches,” and 

6.2, “Excluded Ditches,” in this RTC for a focused description of how the exclusions 

for ditches were revised and clarified for the final rule.

8.21 The Agencies’ proposed definition for “tributary” is overly broad and lacks sufficient 

clarity. As noted above, the Agencies’ definition fails to give adequate consideration to 

 

1

79 Fed. Reg. at 22,201.
Clean Water Rule Response to Comments – Topic 8: Tributaries

38

the plurality opinion in Rapanos and the holding in SWANCC, and it relies almost 

exclusive on legally irrelevant portions of Justice Kennedy’s concurring opinion in 

Rapanos or an incorrect interpretation of ‘significant nexus’ to mean any hydrologic 

connection. Moreover, even if the Agencies’ definition for “tributary” were consistent 

with the law, it is ambiguous, leaving the regulated public to guess as to which water 

bodies the Agencies intend to regulate. The Agencies propose to identify a “tributary” 

based on the presence of a bed, bank, OHWM, and any minimal amount of flow that 

eventually reaches navigable waters. As Justice Kennedy stated in his Rapanos opinion, 

however, these terms are not sufficiently detailed to provide appropriate limits on the 

Agencies’ exercise of jurisdiction.2

The terms used by the Agencies to define “tributaries” should be clarified. The terms 

“bed” and “bank” can include any land at lower elevation that lies between lands at 

higher elevation. All but the flattest terrain will feature some natural areas of lower 

elevations that water will follow. The term “OHWM” is similarly broad, and can 

encompasses any physical sign of water flow, such as changes in the soil, vegetation or 

debris. The Agencies themselves have admitted that their definition of OHWM is vague, 

ambiguous, and inconsistently applied.3The Agencies should revise the rule to clarify 

how field staff will determine the presence of a bed, bank, and OWHM.

In determining whether a water body is a jurisdictional tributary, the Agencies should 

consider not only the presence of these features but also factors such as the frequency, 

duration, volume of flow and significance to receiving waters. As discussed above, the 

Agencies must consider such factors to maintain consistency with Justice Kennedy’s 

concurring opinion in Rapanos and to give meaning to the word “navigable” in the CWA.

The jurisdictional status of Southeast Alaska water bodies will be particularly difficult to 

determine for streams that contribute no direct flow to navigable waters, but may 

contribute flow “indirectly,” through other waters, especially in short seasonal high water 

events in a region that gets 100 to 200 inches of precipitation annually. The Agencies fail 

to clarify how such an indirect contribution may be identified, and fail to specify whether 

such a contribution must be made via a surface water connection or rather, in the 

Agencies’ view, may be made via groundwater. To the extent that the Agencies intend to 

establish indirect connections via groundwater, Sealaska objects to such an interpretation, 

which is unsupported by the CWA or any of the Supreme Court’s decisions. (p. 13-14)

Agency Response: Section I of the Technical Support Document describes the 

legal basis of the final rule and Section VII describes the rationale and support for 

the tributaries definition. The term “ordinary high water mark” has been defined 

in Corps regulations since 1986, and used by Corps Districts nationwide to 

determine the lateral limits of jurisdiction over non-tidal water bodies for the CWA 

section 404 permitting program. As described in the preamble, for purposes of the 

 

2 Rapanos, 547 U.S. at 734.

3 GAO Report “Waters and Wetlands: Corps of Engineers Needs to Evaluate Its District Office Practices in 

Determining Jurisdiction, Feb. 2004, available at ___. See also Farm Bureau Testimony (“the Corps’ Philadelphia 

District has observed that, due to inconsistent interpretations of the OHWM concept, as well as inconsistent field 

indicators and delineation practices, identifying precisely where the OHWM ends is nothing more than a judgment 

call.”).
Clean Water Rule Response to Comments – Topic 8: Tributaries

39

rule, “bed and banks” means the substrate and sides of a channel between which 

flow is confined. The banks constitute a break in slope between the edge of the bed 

and the surrounding terrain, and may vary from steep to gradual. See also 

summary response 8.3. 

North Dakota Office of the Governor et al. (Doc. #15365)

8.22 2. The definition of tributary in the proposed rule is expansive and unacceptable to 

the State of North Dakota.

The proposed rule attempts to establish a chain of nexus extending up endless orders of 

streams into ephemeral flows in washes, drains, and ditches feeding the higher order 

navigable streams. This federal jurisdictional claim violates the intent of the court 

outlined in Rapanos. Instead of regulating the water quality effects of distant tributaries 

on the navigable streams, EPA proposes regulating water quality within tributaries 

themselves.

Take, for example, if federal water quality standards specify that a certain nutrient may 

not exceed a specific amount in a navigable stream. The proposed rule would subject 

influent tributaries to that same standard, rather than regulating the tributary’s 

contribution to the standard in the navigable stream. Next, the lower order tributary 

influent to the first tributary is regulated not by the effect on the navigable water, or even 

the first tributary, but is subjected to the same standard as the navigable water. This 

overreaching jurisdiction is applied up into washes, ditches, and drains, which are 

themselves subjected to the standard applied to the navigable waterbody itself.

The cumulative effect of the above outlined water bodies on receiving navigable water 

bodies is moderated by timing, freshwater influx from stream beds and seeps, and other 

minimally affected tributaries. These factors make it so any given individual tributary or 

drain may have little final impact on the major receiving waterbody. To claim authority 

and apply the same standard within a flowing agricultural or municipal drain as is applied 

to an interstate water--without reference to intervening moderating effects--allows federal 

micromanagement and interference with virtually all human enterprises and a blank 

check to apply standards in any manner it chooses. EPA and cooperating federal agencies 

are appropriating for themselves the authority to become the arbiter of all economic 

enterprises and the power to impede or vet them at will.

EPA must limit its federal jurisdictional claims to a nexus that is defined by proximity, 

not remote connectivity. (p. 3-4)

Agency Response: See summary response for section 8.1 and 8.1.1. Section I of 

the Technical Support Document describes the legal basis of the final rule. Existing 

regulations addressing water quality standards for waters of the United States 

provide that states may modify standards for streams with natural ephemeral flow 

but may not declare an ephemeral stream non-jurisdictional altogether. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

determination that waters meeting the definition of “tributary” in the final rule 

have a significant nexus because they significantly affect the chemical, physical, and 

biological integrity of traditional navigable waters, interstate waters, and the 

territorial seas.
Clean Water Rule Response to Comments – Topic 8: Tributaries

40

Ohio Department of Natural Resources et al. (Doc. #15421)

8.23 Under the agencies' proposed rule, when a tributary flows through a wetland into another 

tributary (e.g., a run-of-stream wetland), losing its OHWM through the wetland, It 

remains a tributary, and the wetland itself is considered a tributary. Logically, one would 

assume that as a tributary (such as a stream) entered a wetland and completely lost Its 

defined bed, bank, and OHWM, it would no longer be considered a stream type 

"tributary", but rather a wetland type "tributary." However, the rule is unclear. From the 

perspective of a regulator or an applicant, would the "tributary" be considered wetland, 

stream, or both as it passes through the wetland? What about a run-of-stream 

Impoundment? How would you calculate a stream length for a tributary that had lost its 

OHWM while passing through a wetland or Impoundment? This will have important 

implications for waterway permit thresholds based on acreage and/or linear footage of 

resources. It would also have implications on mitigation requirements. This is another 

example where defining the specific types of "tributary" (streams, ditches, ponds, lakes, 

etc ...) would be critical for practical implementation of the proposed rule change. Failure 

to do so would result in continued regulatory inconsistencies across the nation. (p. 9)

Agency Response: See summary response for section 8.1.

8.24 Ohio EPA Comments:

The definition as proposed is lengthy and difficult to understand, especially for the 

landowner and general public. Ohio EPA would recommend the alternative approach 

suggested in the preamble text. (p. 24)

Agency Response: See summary response for section 8.1.

Wyoming Department of Environmental Quality (Doc. #16393)

8.25 The proposed rule assumes jurisdiction over multiple categories of waters. The most 

troubling parts - and there are many - involve determinations for "tributaries" and "other 

waters." Tributaries are defined in the proposed rule as waters that have a bed, bank and 

high water mark and contribute some flow to a navigable water. But the inclusion of a 

"flow" condition in this definition is meaningless given the rule's formulation of the 

jurisdictional test. All tributaries under the proposed rule would be considered 

jurisdictional because in the aggregate they are considered to have a significant effect on 

downstream waters. The amount or frequency of flow from any particular tributary will 

not be considered because flow is presumed to occur at some point in time, even when it 

is rare. Therefore, in reality, any channel with a bed, bank and high watermark would 

become jurisdictional under this rule regardless of the amount of flow.

In arid states like Wyoming and much of the Western United States, a considerable 

percentage of the mapped ephemeral stream miles are actually grassy swales or erosional 

gullies. These may or may not meet the tributary criteria in the proposed rule (bed, bank 

and high water mark) and likely will require a case-by-case evaluation, undermining the 

regulatory certainty espoused by EPA and the Corps. In addition, there are many more 

miles of unmapped drainages and channels, all of which are subject to water quality 

standards and discharge permitting requirements in Wyoming under existing state law. 

All would likely be considered "other waters" under the proposed rule, and may or may 

not be jurisdictional depending upon a case-specific determination. How those 
Clean Water Rule Response to Comments – Topic 8: Tributaries

41

determinations will be made is not clear under the proposal, but the process seems to rely 

on a very poorly developed concept of evaluating similarly situated drainages in the area. 

In contrast, the plurality opinion in Rapanos, which has been ignored by the federal 

agencies, described a much clearer concept by requiring the presence of a relatively 

permanent flow and a hydrologic surface connection to another water of the United States 

in order to establish jurisdiction.

These uncertainties will have very real impacts in Wyoming. Based on the 1:24,000 scale 

National Hydrographic Dataset (NHD), approximately 80% of Wyoming's stream miles 

are intermittent or ephemeral. While the portion that is ephemeral cannot be precisely 

estimated with available data, it is widely known that ephemeral channels comprise a 

large fraction of stream miles in arid and semi-arid regions. (p. 4)

Agency Response: See summary response for section 8.1. Paragraph (b) of the 

final rule excludes many features, including non-wetland swales, grassed waterways, 

and erosional features like gullies and rills that do not meet the definition of 

tributary. See section IV(I) of the preamble to the final rule and summary 

responses in Compendium 7 “Features and Waters Not Jurisdictional,” for a broad 

discussion of the final rule’s exclusions. Section VII of the Technical Support 

Document discusses the science supporting the agencies’ determination that waters 

meeting the definition of “tributary” in the final rule have a significant nexus 

because they significantly affect the chemical, physical, and biological integrity of 

traditional navigable waters, interstate waters, and the territorial seas. Section I of 

the Technical Support Document describes the legal basis of the final rule.

Indiana Department of Environmental Management (Doc. #16440)

8.26 d. The final rule must clarify that connecting waters will themselves not be 

considered jurisdictional.

The proposed definition of "tributary" includes water that goes underground and the 

proposed definition of "neighboring" includes water that has a connection to navigable 

water only through shallow groundwater or through a "confined surface hydrologic 

connection." We question the inclusion of groundwater as connecting water. Regardless 

of how connections are defined, the final rule must clarify that it is not the Agencies' 

intent to claim jurisdiction over the connecting features themselves. (p. 5)

Agency Response: Section VIII of the Technical Support Document addresses 

“adjacent waters,” including the revised and clarified definition of “neighboring.” 

Groundwater is explicitly excluded under paragraph (b) of the final rule.

Office of the Governor, State of Utah (Doc. #16534)

8.27 The Proposed Rule declares that all "tributaries" of both core waters and impoundments 

of core waters (dams or reservoirs) are always covered by the CWA.4The Proposed 

definition of "tributaries" is extremely broad, and includes "ponds, impoundments, 

 

4

See 79 Fed. Reg. 22263 (proposed April 21, 2014) (to potentially be codified at 40 C.F.R. § 230.3(s)(5)).
Clean Water Rule Response to Comments – Topic 8: Tributaries

42

canals, and ditches" not otherwise excluded in the proposed rule.5 Waters are even 

deemed tributaries under the proposed rule "if they contribute flow, either directly or 

through another water" to a jurisdictional water, and tributaries are still deemed as such 

even if the water passes man-made breaks such as "culverts, pipes, or dams.”6The EPA 

and Army explain that this definition is correct because the tributaries "significantly" 

affect chemical, physical and biological integrity of traditional navigable waters, 

interstate waters, and/or territorial seas. Specifically, the term "significant" is used to 

justify the expansion to the proposed rules tributary definition. However, "significance" 

has not been clearly defined with quantitative measures of the chemical, biological, or 

physical effects of a tributary on downstream waters. The absence of quantitative 

measures makes it extremely difficult to determine which waters qualify as a tributary. 

(p. 8-9)

Agency Response: See summary response for section 8.1. Section VII of the 

Technical Support Document discusses the science supporting the agencies’ 

determination that waters meeting the definition of “tributary” in the final rule 

have a significant nexus because they significantly affect the chemical, physical, and 

biological integrity of traditional navigable waters, interstate waters, and the 

territorial seas.

State of South Dakota (Doc. #16925)

8.28 Tributaries Determined Jurisdictional-by-Rule - SDDOT recommends modifying the 

proposed rule to ensure that tributaries are evaluated under the same criteria used in the 

2008 Guidance. Tributaries should be deemed jurisdictional by rule only if they have 

perennial flow, that is typically flow year-round or have continuous flow seasonally. 

Such tributaries must include the presence of bed and banks with ordinary high water 

marks. Without this requirement, the universe of tributaries deemed jurisdictional is 

unreasonably broadened. The final rule should clarify that exclusions take precedence 

over the jurisdictional-by-rule provisions and, therefore, if a ditch is excluded by 

paragraphs (b)(3) or (b)(4) , the ditch would be non-jurisdictional. (p. 5)

Agency Response: See summary response for section 8.1. Section VII of the 

Technical Support Document discusses the science supporting the agencies’ 

determination that waters meeting the definition of “tributary” in the final rule 

have a significant nexus because they significantly affect the chemical, physical, and 

biological integrity of traditional navigable waters, interstate waters, and the 

territorial seas. Paragraph (b) of the final rule excludes most ditches that are not

relocated tributaries or excavated in tributaries and makes it clear that all of the 

features excluded in paragraph (b) “are not waters of the United States even where 

they otherwise meet the terms of paragraphs (a)(1) through (a)(8)” of the rule. 

Thus, any feature excluded under paragraph (b) may not be considered waters of 

the United States under any other provision of the rule.

 

5

See 79 Fed. Reg. 22263 (proposed April21, 2014) (to potentially be codified at40 C.F.R. § 230.3(u)(5)).

6

Id.
Clean Water Rule Response to Comments – Topic 8: Tributaries

43

Allen Boone Humphries Robinson LLP (Doc. #19614)

8.29 "Tributary" is defined in the Proposed Rule as "a water physically characterized by the 

presence of a bed and banks and ordinary high water mark [OHWM] . .. which 

contributes flow, either directly or through another [jurisdictional water]," and, 

additionally, "wetlands, lakes, and ponds are tributaries (even if they lack a bed and 

banks or ordinary high water mark) if they contribute flow."7This proposed definition of 

“tributary" is vague and overbroad. In many locations a bed, banks and OHWM cannot 

be easily identified. The definition is silent as to volume or frequency of flow. And 

"tributary" could be interpreted to include man-made waters with artificial features, such 

as drainage ditches or artificial ponds. This ambiguity will require extensive examination 

of miles of upstream tributary features, and create uncertainty and the potential for 

jurisdictional over-reaching. (p. 7)

Agency Response: See summary responses for sections 8.1, 8.1.2 and 8.4.

Franconia Township, Pennsylvania (Doc. #8661)

8.30 This definition, if adopted, would significantly increase the jurisdictional reach of the 

CWA. This definition will bring into play countless streams, creeks, rivulets, washes, and 

other features where water does, will or could run to (eventually) navigable waters. We 

believe there needs to be a limit, a "bright line" set by the rule as to just how far the CWA 

manifests its dominion over local, regional and state waters. The agencies continue to say 

the proposed rule will not expand this jurisdiction, but we believe otherwise. (p. 2)

Agency Response: See summary response for section 8.1. Paragraph (b) of the 

final rule excludes many features. See section IV(I) of the preamble to the final rule 

and summary responses in Compendium 7 “Features and Waters Not 

Jurisdictional,” for a broad discussion of the final rule’s exclusions. 

8.31 The agencies should provide assurances in a final rule that the definition of "tributary" 

will be limited to those with "bed and banks with an ordinary high water mark" that have 

formed over several years, and that would not include temporary accumulations of 

sediment or hydraulic activity resulting from specific isolated precipitation or runoff 

events. Definitions must be fleshed out for the terms "ordinary high water mark", "bed 

and banks", and other subjective terminology used in the proposed rule that can and will 

cause uncertainty in the implementation of a final rule. Jurisdictional tributaries should 

meet a new " bright line" test related to size of bed and banks, amount of flow, distance 

from the jurisdictional navigable water in order to be considered a "water of the U.S.", or 

establishing a limit on just how small or how far upstream the CWA would apply from 

the jurisdictional navigable water. (p. 2-3)

Agency Response: See summary response for section 8.1. The term “ordinary 

high water mark” has been defined in Corps regulations since 1986, and used by 

Corps Districts nationwide to determine the lateral limits of jurisdiction over nontidal water bodies for the CWA section 404 permitting program. As described in 

the preamble, for purposes of the rule, “bed and banks” means the substrate and 

 

7

79 Fed. Reg. at 22,263.
Clean Water Rule Response to Comments – Topic 8: Tributaries

44

sides of a channel between which flow is confined. The banks constitute a break in 

slope between the edge of the bed and the surrounding terrain, and may vary from 

steep to gradual. 

City of Escondido (Doc. #11116)

8.32 Expansion of the Definition of Waters of the U.S. The expansion of the definition of 

Waters of the U.S. is seen in the last three bullets of the definition (page 22913) relating 

to:

 All tributaries of a traditional navigable water, instate water, the territorial seas 

or impoundment;

 All waters, including wetlands, adjacent to a traditional navigable water, 

interstate water, the territorial seas, impoundment or tributary; and

 On a case-specific basis other waters, including wetlands, provided that those 

waters alone, or in combination with other similarly situated waters, including 

wetlands, located in the same region, have a significant nexus to a traditional 

navigable water, interstate water or the territorial seas.

How would we define a tributary? Could this be a storm drain that has persistent dry 

weather flows? This could mean that we could not maintain our storm drain system 

without obtaining a permit. We recommend that the first bullet be revised to 

specifically limit the tributary to downstream of a stormdrain or channel outlet to a 

stream. If not, storm drain systems should be specifically excluded from the 

definition. (p. 1-2)

Agency Response: See summary response for section 8.1. Paragraph (b) of the 

final rule excludes many features, including most ditches that are not relocated 

tributaries or excavated in tributaries and erosional features that do not meet the 

definition of tributary and stormwater control features created in dry land. See 

section IV(I) of the preamble to the final rule and summary responses in 

Compendium 7 “Features and Waters Not Jurisdictional,” for a broad discussion of 

the final rule’s exclusions. See summary responses for section 6.0, “Ditches,” and 

6.2, “Excluded Ditches,” in this RTC for a focused description of how the exclusions 

for ditches were revised and clarified for the final rule.

Clark County Regional Flood Control District, Nevada (Doc. #11726)

8.33 While it is true that some ephemeral streams are headwaters for the nation's major rivers, 

not all ephemeral streams are headwaters. Many ephemeral washes in the desert 

southwest may not convey any actual water to downstream "waters" for years on end. In 

these washes, the presence of an ordinary high water mark indicates only that water has 

flowed through the area at some time in the past, NOT that it ordinarily flows through 

there. (p. 2)

Agency Response: See summary responses for sections 8.1 and 8.4.
Clean Water Rule Response to Comments – Topic 8: Tributaries

45

Uintah County, Utah (Doc. #12720)

8.34 Because the definition proposed for tributary is so broad, the Agencies could insert 

themselves into local building and zoning processes. In a rural setting like the majority of 

the western United States, individual homes could be subject to EPA or COE approval 

for any aspect of design and construction where natural run-off would not be captured by 

a waste water system. Purely from the standpoint of the affect of gravity upon water, the 

case makes itself that water flows downhill. The notion that any flow in any physical 

feature, dry or wet, qualifies it as a water of the US is nonsense. (p. 4)

Agency Response: The agencies have no desire to be involved with local building 

or zoning processes. See summary response for section 8.1.

National Association of Flood & Stormwater Management Agencies (Doc. #13613)

8.35 NAFSMA appreciates the agencies’ efforts to provide new definitions in the proposed 

rule but we are concerned that the definitions are not clear and in aggregate, are 

excessively expansive. As an example, per (a)(5), all tributaries would be WOTUS; then 

(a)(6) establishes area adjacent to Tributaries as WOTUS; then, (c)(1) Adjacent includes 

Neighboring, which is subsequently defined to include (c)(3) Riparian Area and (c)(4) 

Floodplain. By multiple convoluted definitions, a tributary has become categorically vast. 

Consequently, WOTUS encompasses noncontiguous areas in the floodplain and riparian 

areas neighboring a tributary, which could be (but may not have to be) a bed and bank 

with an Ordinary High Water Mark, but does not have to be flowing. Under these 

definitions, the entire watershed could be categorically determined to be WOTUS which 

is inconsistent with EPA’s stated intent. Furthermore, since definition (c)(2) Tributary 

specifies that shallow subsurface hydrologic connections can be jurisdictional nexus, 

WOTUS could extend beyond the surface water watershed boundaries. (p. 3)

Agency Response: See summary response for section 8.1. See section IV(I) of the 

preamble to the final rule and summary responses in Compendium 7 of this RTC, 

“Features and Waters Not Jurisdictional,” for a broad discussion of the final rule’s 

exclusions. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ determination that waters meeting the definition of 

“tributary” in the final rule have a significant nexus because they significantly affect 

the chemical, physical, and biological integrity of traditional navigable waters, 

interstate waters, and the territorial seas. Section VIII of the Technical Support 

Document addresses “adjacent waters,” including the revised and clarified 

definition of “neighboring.”

Board of County Commissioners, Otero County, New Mexico (Doc. #14321)

8.36 The definition of “tributary”: For legal and scientific clarity, the agencies should 

withdraw the Proposed Rule and replace it with a rule that defines tributaries as only 

those waters that maintain a permanent, surface water connection to an (a)(1) or (a)(3) 

water. (p. 14)

Agency Response: See summary response for section 8.1.
Clean Water Rule Response to Comments – Topic 8: Tributaries

46

Board of County Commissioners, Delta County, Colorado (Doc. #14405)

8.37 The proposed rule presumes that all ephemeral and includes intermittent drainages that 

have the presence of a bed and banks and an Ordinary High Water Mark (OHWM) and 

that contribute flow, either directly or through water, to a WUS are jurisdictional. The 

proposed rule does not recognize that there are differences among not only types of 

drainages, but individual drainages and their potential for affecting the chemical, 

physical, or biological integrity of a Waters of the United States (WUS). The proposed 

presumption of jurisdiction by rule for ephemeral and intermittent drainages runs counter 

to the guidance and process established by the SWANCC and Rapanos opinions.

The broad definition of tributaries encompasses ponds, ditches and other features that are 

beyond the agencies' authority. The plain language of the definition of tributary 

encompasses numerous isolated and, in many cases, dry features that are far beyond the 

agencies' authority under the CWA. It would encompass isolated ponds not otherwise 

excluded that somehow be connected through a surface connection, groundwater, or any 

other connection to a nearby (a)(1) through (4) water. It encompasses isolated wetlands in 

pastures that may be connected to a nearby creek through ground water or ditches. It 

encompasses virtually all artificial stock ponds west of the Mississippi River, of which, 

virtually all will have been built on a drainage (and ephemeral streams) in order to fill 

with water. It is clear that the plain language of the definition makes the category almost 

limitless.

Delta County BoCC assert that the agencies' definition of "tributary" is a limitless 

category that has the potential to wrap every natural pond, isolated wetland, or ditch into 

the federal regulatory scheme, which violates the language and spirit of the Supreme 

Court's decisions in SWANCC and Rapanos.

8

It is clear that the phrase "waters of the 

U.S." is not limitless, yet that is exactly what the agencies have proposed through their 

broad and ill-defined term "tributary." Key phrases have been left undefined. The 

definition for "through another water," a key phrase in the definition, was simply left out 

by the agencies. Not only does this foster confusion instead of clarity in the regulated 

community, it could be stretched by regulators or litigants now or in the future. If the 

agencies' intent was not to create such a broad definition, than they should have put such 

intent in the regulation. 

The agencies cannot categorically make anything with a bed, bank and OHWM that takes 

water somewhere downstream jurisdictional. The proposed rule is clear that the definition 

of `tributary' does in fact include all ephemeral, intermittent and perennial features and 

that rate of flow (or any flow) is simply not a factor. (Proposed Rule at 22206; ("...the 

agencies conclude that tributaries, including headwaters, intermittent, ; intermittent and 

ephemeral streams, and especially when all tributaries in a watershed are considered in 

combination, have a significant nexus to traditional navigable waters, interstate waters, or 

 

8 Rapanos v. United States, 547 U.S. 715 (2006); (J. Scalia, Indicating "navigable" invokes a limit on the CWA

jurisdiction the plurality stated "...that the qualifier "navigable" is not devoid of significance ... the waters of the

United States in 1362(7) cannot bear the expansive meaning that the Corps would give it"); SWANCC v. U.S. Army

Corps of Engineers, 531 U.S. 159 (2001); (In striking down the agencies' Migratory Bird Rule the court stated, "we 

find nothing approaching a clear statement from Congress that it intended 404(a) to reach an abandoned sand and 

gravel pit such as we have here").
Clean Water Rule Response to Comments – Topic 8: Tributaries

47

territorial seas...")). Delta BoCC believes that the definition of tributary is overly broad 

because the agencies cannot make all tributaries per se jurisdictional without satisfying 

the significant nexus analysis. (p. 3-4)

Agency Response: See summary response for section 8.1. Section I of the 

Technical Support Document describes the legal basis of the final rule. Paragraph 

(b) of the final rule excludes many features, including most ditches that are not 

relocated tributaries or excavated in tributaries and erosional features that do not 

meet the definition of tributary. See section IV(I) of the preamble to the final rule 

and summary responses in Compendium 7 of this RTC, “Features and Waters Not 

Jurisdictional,” for a broad discussion of the final rule’s exclusions.

Board of Supervisors, Cochise County, Arizona (Doc. #14541)

8.38 As noted in the proposed rule on page 22192, a "four-Justice plurality in Rapanos

interpreted the term "waters of the United States" as covering "relatively permanent, 

standing or continuously flowing bodies of water ... that are connected to traditional 

navigable waters ... ," Many of the tributaries and other waters that the agencies are trying 

to include as jurisdictional fail to meet this requirement. The definition of a tributary 

must be rewritten to include the four-Justice requirements in Rapanos. The proposed rule 

ignores this requirement and must be rewritten to address this requirement in addition to 

the significant nexus requirement on which it is currently based.

Also as noted in the proposed rule on page 22213, "Justice Kennedy was clear that waters 

with a significant nexus must significantly affect the chemical, physical, or biological 

integrity of a downstream navigable water and that the requisite nexus must be more than 

"speculative or insubstantial," ... " While some tributaries may have connectivity with the 

jurisdictional a(1) to a(3) waters of the US, their contribution to the downstream 

navigable water is extremely minor when compared with other tributaries in the total sum 

of contributions. As a result, the nexus for that tributary with the jurisdictional water 

becomes insubstantial and thus insignificant, and that tributary does not have a significant 

nexus. As a result of this rationale, the definition for tributary should be revised to 

include the requirement that the tributary provides a significant contribution to the 

navigable water. This same rationale applies to "other waters" as described in the 

proposed rule.

Further, the agencies have drawn the conclusion that "While Justice Kennedy focused on 

adjacent wetlands in light of the facts of the cases before him, it is reasonable to utilize 

the same standard for tributaries." However, the agencies fail to include the requirements 

of the four-Justice plurality of "relatively permanent, standing or continuously flowing 

bodies of water" to that conclusion. This conclusion must be revised in light of that 

requirement. (p. 1-2)

Agency Response: Section I of the Technical Support Document describes the 

legal basis of the final rule. 

Waters of the United States Coalition (Doc. #14589)

8.39 Definition of “Tributary” – The Proposed Rule will reclassify manmade channels that 

discharge to traditional navigable waters as “waters of the United States.” This change 
Clean Water Rule Response to Comments – Topic 8: Tributaries

48

will capture aqueducts, storm drain systems, and other manmade channels. Under the 

Clean Water Act, these conveyances are point sources that discharge into waters of the 

United States rather than waters of the United States themselves. Designation as waters of 

the United States will interfere with or prevent manmade channels from being used to 

convey water whether it is in a water supply, flood control, or waste treatment capacity. 

(p. 4)

Agency Response: See summary response for section 8.1, 8.1.1 and 8.1.2.

Paragraph (b) of the final rule excludes many features, including waste treatment 

systems designed to meet the requirements of the CWA, stormwater control features 

created in dry land and most ditches that are not relocated tributaries or excavated 

in tributaries. See section IV(I) of the preamble to the final rule and summary 

responses in Compendium 7 of this RTC, “Features and Waters Not Jurisdictional,” 

for a broad discussion of the final rule’s exclusions.

Board of Supervisors, San Joaquin County, California (Doc. #15017.1)

8.40 Jurisdictional tributaries should meet a new "bright line" test related to size of bed and 

banks, amount, duration and frequency of flow, or distance from the jurisdictional 

navigable water in order to be considered a "water of the U.S.", establishing limits based 

on size, flow volume and frequency, and/or distance from the jurisdictional navigable 

water where the CWA would apply. Finally, wetlands should not be considered 

"tributaries" in the final rule, as they should have to meet "adjacency" or "significant 

nexus" tests associated with "adjacent" or "other waters" to be considered "waters of the 

U.S." (p. 4)

Agency Response: See summary response for section 8.1, 8.1.1 and 8.1.2.

Flood Control and Water Conservation District, Alameda County, California (Doc. #15074)

8.41 4. The proposed rule defines tributary as “water physically characterized by the presence 

of bed and banks and ordinary high water mark (OHWM) (33CFR 328.3(e) and 

contributes flows as describe in paragraph (a) (1) through (4). However, it is not clear 

what flow discharge basis (i.e.; 2-year or 10 year) should be used in to delineating the 

lateral extent of Waters and other waters. The proposed use of Lichvar methodology 

(based on geomorphology) overestimates the lateral extent of the OHWM. The 

characteristic soil, vegetation and or descendible hydrology required to confer 

jurisdiction are often discounted or ignored. This results in excessively large 

jurisdictional areas and corresponding high mitigation demands. The rulemaking process 

should consider a method that is science based, equitable and truly results in meeting the 

intent of the Clean Water Act. (p. 2)

Agency Response: See summary responses for sections 8.1, 8.1.1 and 8.1.2.

National Association of Counties (Doc. #15081)

8.42 Recommendations

...
Clean Water Rule Response to Comments – Topic 8: Tributaries

49

 Create a national map that clearly shows which waters and their tributaries are 

considered jurisdictional

... (p. 11)

Agency Response: Determining the jurisdictional status of a water feature often 

requires site specific knowledge. Although the final rule provides increased clarity 

and “bright line” distinctions to help differentiate waters of the United States from 

non-jurisdictional features, it will not eliminate the need for consideration of site 

specific knowledge. The agencies generally only conduct jurisdictional 

determinations at the request of individual landowners, thus we do not have maps 

depicting the geographic scope of the CWA. Such maps do not exist and the costs 

associated with a national effort to develop them are cost prohibitive and would 

require access to private property across the country. The U.S. Geological Survey 

and the U.S. Fish and Wildlife Service collect information on the extent and location 

of water resources across the country and use this information for many nonregulatory purposes, including characterizing the national status and trends of 

wetlands losses. This data is publicly available and the agencies have relied on 

USGS and USFWS information to characterize qualitatively the location and types 

of national water resources. This information is depicted on maps but not for 

purposes of quantifying the extent of waters covered under CWA regulatory 

programs.

Painesville Township, Ohio (Doc. #15183)

8.43 This definition, if adopted, would significantly increase the jurisdictional reach of the 

CWA. This definition will bring into play countless streams, creeks, rivulets, washes, and 

other features where water does, will or could run to (eventually) navigable waters. We 

believe there needs to be a "bright line" set by the rule as to just how far the CWA 

manifests its dominion over local, regional and state waters. (p. 1-2)

Agency Response: See summary response for section 8.1. Paragraph (b) of the 

final rule excludes many features. See section IV(I) of the preamble to the final rule 

and summary responses in Compendium 7 of this RTC, “Features and Waters Not 

Jurisdictional,” for a broad discussion of the final rule’s exclusions. 

Department of Public Works, County of San Diego, California (Doc. #17920)

8.44 Simplify the definition for tributaries

The definition for tributaries should be revised to contain less subjective terms, include 

appropriate exemptions, and be simply defined so as to minimize broad interpretation. 

Tributaries have never before been defined in the regulations for Waters of the U.S. In 

the proposed rule, the definition for tributaries is vaguely defined, lacking necessary 

exemptions, and containing many subjective terms. Furthermore, this definition of 

tributary could be interpreted to include stormwater conveyance or treatment facilities 

that previously were not defined as a tributary. By broadening the definition, clean-up 

activities in stormwater conveyance channels could trigger the need for additional 

permits and lengthy certification processes. Because man-made features could be 

considered tributaries under the proposed definition, it should be revised to include 
Clean Water Rule Response to Comments – Topic 8: Tributaries

50

appropriate exemptions for features that require County maintenance and oversight. 

Features such as BMPs, roadside ditches, and water conveyances should be exempt. 

Additionally, the definition states that the flow in the tributary may be ephemeral, 

intermittent or perennial. These terms are not further defined in the new rule, and can 

have varying definitions. To avoid broad and subjective interpretation, the terms 

ephemeral and intermittent should be removed, as these terms could be applied to any 

area that is wet and carries water during a single rain event. The term perennial is more 

appropriate for the definition of tributaries and in-line with the existing regulatory 

language, which defines a tributary as being relatively permanent.

EXAMPLE: The County maintains and monitors waterways including roadside ditches, 

flood control channels, and drainage conveyances, which are used to safely guide water 

away from homes, businesses, properties and roads. Man-made feature s such as ditches 

and canals can be considered tributaries under the proposed definition. Therefore, the 

definition needs to be revised to contain appropriate exemptions in order to appropriately 

monitor and maintain these features. In addition, a ditch that carries water once a year 

and ultimately connects to a Traditionally Navigable Water can be considered ephemeral 

and, therefore, would be a tributary based on the new definition. The word ephemeral

should be eliminated from the definition because it can be too broadly and subjectively 

applied. (p. 7)

Agency Response: See summary response for section 8.1. Paragraph (b) of the 

final rule excludes many features, including waste treatment systems designed to 

meet the requirements of the CWA, stormwater control features created in dry land 

and most ditches that are not relocated tributaries or excavated in tributaries. See 

section IV(I) of the preamble to the final rule and summary responses in 

Compendium 7 of this RTC, “Features and Waters Not Jurisdictional,” for a broad 

discussion of the final rule’s exclusions. All existing statutory exemptions, including 

those exempting maintenance of existing irrigation and drainage ditches from CWA 

section 404 permitting, remain in effect and unchanged by the final rule. Section 

IV(F) of the preamble to the final rule describes flow regimes, as they are related to 

tributaries and ditches. Section VII of the Technical Support Document discusses 

the science supporting the agencies’ determination that waters meeting the 

definition of “tributary” in the final rule have a significant nexus because they 

significantly affect the chemical, physical, and biological integrity of traditional 

navigable waters, interstate waters, and the territorial seas. Section VIII of the 

Technical Support Document addresses “adjacent waters.”

Butte County Administration, County of Butte, California (Doc. #19593)

8.45 The agencies should provide assurances in a final rule that the definition of “tributary” 

will be limited to those with “bed and banks with an ordinary high water mark” that have 

formed over several years, and that would not include temporary accumulations of 

sediment or hydraulic activity resulting from specific isolated precipitation or runoff 

events. Definitions must be fleshed out for the terms “ordinary high water mark”, “bed 

and banks”, and other subjective terminology used in the proposed rule that can and will 

cause uncertainty in the implementation of a final rule.
Clean Water Rule Response to Comments – Topic 8: Tributaries

51

Also, the SAB recently advised the EPA to reconsider the definition of tributaries in the 

proposed rule because the SAB maintains that not all tributaries may have ordinary high 

water marks. The SAB stated that “an ordinary high water mark may be absent in 

ephemeral streams within arid and semi-arid environments or in low gradient landscapes 

where the flow of water is unlikely to cause an ordinary high water mark.”9 The SAB 

advised the agency to “consider changing the wording in the definition to ‘bed, bank, and 

other evidence of flow’.”10 We believe this would further broaden the jurisdiction of the 

CWA beyond what Congress intended, as any indication of surface water runoff from an 

isolated rain event in a field, dirt road or parking lot could meet this new expanded 

definition, becoming a “water of the U.S.” subject to CWA regulation. (p. 5)

Agency Response: See summary response for section 8.1 and 8.1.2. See also 

Section 9 “Scientific Evidence Supporting the Rule” of the Response to Comments.

The term “ordinary high water mark” has been defined in Corps regulations since 

1986, and used by Corps Districts nationwide to determine the lateral limits of 

jurisdiction over non-tidal water bodies for the CWA section 404 permitting 

program. As described in the preamble, for purposes of the rule, “bed and banks” 

means the substrate and sides of a channel between which flow is confined. The 

banks constitute a break in slope between the edge of the bed and the surrounding 

terrain, and may vary from steep to gradual. 

Board of Supervisors, Sutter County, California (Doc. #19657)

8.46 ... Jurisdictional tributaries should meet a new "bright line" test related to size of bed and 

banks, amount of flow, distance from the jurisdictional navigable water in order to be 

considered a "water of the U.S.", or establishing a limit on just how small or how far 

upstream the CWA would apply from the jurisdictional navigable water. Wetlands should 

also not be considered "tributaries" in the final rule, as they should have to meet 

"adjacency" or "significant nexus" tests associated with "adjacent" or "other waters" to be 

considered "waters of the U.S."

...

To address these issues, we request that the agencies make the following changes to the 

Proposed Rule: 

 Revise the proposed definition of "tributary" in 33 CF.R § 328.3(c)(S) to exclude: 

"any water that contributes flows to waters of the United States, if at all, 

exclusively as a result of mechanical pumping." 

...(p. 7, 8)

Agency Response: See summary response for section 8.1, 8.1.1 and 8.1.2.

 

9

[EPA-SAB-14-007] Science Advisory Board letter to EPA Administrator Gina McCarthy dated September 30, 

2014 re: Science Advisory Board (SAB) Consideration of the Adequacy of the Scientific and Technical Basis of the 

EPA’s Proposed Rule titled “Definition of Waters of the United States under the Clean Water Act”

10 Id.
Clean Water Rule Response to Comments – Topic 8: Tributaries

52

North Dakota Water Resource Districts Association (Doc. #5596)

8.47 A concern with the jurisdictional by-rule approach to tributaries is that it leaves behind 

Justice Kennedy's narrow "significant nexus" test from Rapanos and adopts merely a 

"nexus'' test, regardless of volume of flow, proximity to navigable waters or other 

relevant factors to the significance of a tributary to a Water. (p. 1)

Agency Response: Section III of the preamble to the final rule and section II of 

the Technical Support Document describes the agencies’ significant nexus analysis. 

Section VII of the Technical Support Document discusses the science supporting the 

agencies’ determination that waters meeting the definition of “tributary” in the final 

rule have a significant nexus because they significantly affect the chemical, physical, 

and biological integrity of traditional navigable waters, interstate waters, and the 

territorial seas.

Utah Association of Counties (Doc. #14756)

8.48 33 CFR 328.3 Current Rule: (5) Tributaries of waters identified in paragraphs (a)(1) 

through (4) of this section;

Proposed Change to 33 CFR 328.3: (5) All tributaries of waters (other than waters that 

are themselves wetlands) identified in paragraphs (a)(1) through (4) of this section, 

provided the tributaries have a significant nexus to such waters; (p. 9-10)

Agency Response: See summary response for section 8.1.

8.49 Proposed Change to 33 CFR 328.3: (5) (4) Tributary. The term tributary means a water 

physically characterized by the presence of a bed and banks and ordinary high water 

mark, as defined at 33 CFR 328.3(e), which contributes flow, either directly or through 

another water, to a water identified in paragraphs (a)(1) through (4) of this section. In 

addition, wetlands, lakes, and ponds are tributaries (even if they lack a bed and 

banks or ordinary high water mark) if they contribute flow, either directly or 

through another water to a water identified in paragraphs (a)(1) through (3) of this 

section. A water that otherwise qualifies as a tributary under this definition does not 

lose its status as a tributary if, for any length, there are one or more man-made 

breaks (such as bridges, culverts, pipes, or dams), or one or more natural breaks 

(such as wetlands at the head of or along the run of a stream, debris piles, boulder 

fields, or a stream that flows underground) so long as a bed and banks and an 

ordinary high water mark can be identified upstream of the break. A tributary, 

including wetlands, can be a natural, man-altered, or man-made water and includes 

waters such as rivers, streams, lakes, ponds, impoundments, canals, and ditches not 

excluded in paragraph (b)(3) or (4) of this section. (p. 17-18)

Agency Response: See summary response for section 8.1.

Washington State Water Resources Association (Doc. #16543)

8.50 The proposal would, for the first time, categorize all “tributaries” as jurisdictional by rule, 

negating any opportunity to scientifically rebut the case for jurisdiction based on such 

factors as the size of the tributary, the temporal nature of its flow, whether the so-called 

waterbody is ephemeral or intermittent in nature, the distance to a traditional navigable 
Clean Water Rule Response to Comments – Topic 8: Tributaries

53

water (TNW), the nature of any breaks in the bed, bank and ordinary high water mark 

(OHWM), whether the waterbody is natural or man-made, and the nature, if any, of 

affects from the tributary on downstream water quality.

...Clarify that jurisdictional “tributaries” are limited to waters that contribute direct flow 

to a traditional navigable water via a continuous surface connection;... (p. 3-4, 15)

Agency Response: See summary response for section 8.1.

8.51 Despite the proposals stated objective to add clarity to the regulatory process, the 

proposal in fact creates great confusion and uncertainty. Some of the unanswered 

questions have been alluded to above, e.g., what will be the effect of the proposal on the 

construction and operation of stormwater control facilities, or the repair and replacement 

of ditches. Other issues that must be addressed, through clarification and in the context of 

an ongoing dialogue amongst stakeholders, include:

...

 Are isolated waters without any direct surface or shallow subsurface connection 

to TNWs, but which periodically capture sheet flows containing pollutants, 

jurisdictional; 

...

 Is it accurate to state that “all” ephemeral or intermittent streams will now be 

considered jurisdictional;

 Is it accurate to state that waters adjacent to tributaries, including non-navigable 

tributaries, regardless of how remote or insubstantial the connection, are now 

jurisdictional;

... 

 If a pipeline is constructed across a normally dry wash or dry arroyo, and the 

construction activity occurs only when water is not flowing, will the project 

nevertheless need a section 404 permit (if the answer is “yes” or “maybe,” are 

there any limits on the amount or frequency of flow that must pass through the 

wash or arroyo);

... (p. 17, 18)

Agency Response: See summary response for section 8.1. Paragraph (b) of the 

final rule excludes many features, including stormwater control features created in 

dry land and most ditches that are not relocated tributaries or excavated in 

tributaries. See section IV(I) of the preamble to the final rule and summary 

responses in Compendium 7 of this RTC, “Features and Waters Not Jurisdictional,” 

for a broad discussion of the final rule’s exclusions. All existing statutory 

exemptions, including those exempting maintenance of existing irrigation and 

drainage ditches from CWA section 404 permitting, remain in effect and unchanged 

by the final rule. Section II of the Technical Support Document describes the 

agencies’ significant nexus analysis. Section VII of the Technical Support 

Document discusses the science supporting the agencies’ determination that waters 

meeting the definition of “tributary” in the final rule have a significant nexus 

because they significantly affect the chemical, physical, and biological integrity of 

traditional navigable waters, interstate waters, and the territorial seas. Section VIII 

of the Technical Support Document addresses “adjacent waters.”
Clean Water Rule Response to Comments – Topic 8: Tributaries

54

League of Oregon Cities (Doc. #16546)

8.52 The EPA "Facts about the Waters of the U.S. Proposal" document indicates that the 

proposed rule "does NOT include any waters that have not have historically been 

covered under the Clean Water Act.” ... Furthermore, the definition of "tributaries", 

which includes certain ephemeral streams, and inclusion of neighboring waters will 

create a broadened scope under which the agencies will have enhanced jurisdictional 

authority. (p. 1)

Agency Response: See summary response for section 8.1. Section I of the 

Technical Support Document describes the legal basis of the final rule, and also 

includes a summary of the historic scope of the existing regulatory definition of 

“waters of the United States.”

Michigan Association of Conservation Districts (Doc. #16583)

8.53 Additional Concerns with the Proposed Rule:

 Tributary Definition. The difference between streams and ditches under the 

definition of tributary is very important to agriculture in Michigan and the 

proposed rule needs to clarify the definition and when, where and how there 

might be a significant nexus between remote drainage features or isolated 

waters and downstream navigable waters. As currently drafted, the proposal 

raises legitimate concerns about the potential regulation of on-farm ditches, 

ponds, and isolated wetlands that are located in a natural stream or have a 

hydrologic connection to a downstream jurisdictional water body. This creates 

the very real potential for the regulation of on-farm water features, regardless 

of intended use. Because of the great diversity in natural features across the 

United States, MACO strongly encourages the use of local input to ascertain 

and develop local parameters, criteria and defined standards regarding the 

relevance of tributaries to traditional navigable WOTUS. (p. 2-3)

Agency Response: See summary response for section 8.1. Paragraph (b) of the 

final rule excludes many features, including prior converted cropland, most ditches 

that are not relocated tributaries or excavated in tributaries, and artificial lakes and 

ponds created in dry land and used primarily for such uses as stock watering, 

irrigation, etc. See section IV(I) of the preamble to the final rule and summary 

responses in Compendium 7 of this RTC, “Features and Waters Not Jurisdictional,” 

for a broad discussion of the final rule’s exclusions. See summary responses for 

section 6.0, “Ditches,” and 6.2, “Excluded Ditches,” in this RTC for a focused 

description of ditches, the regulatory history of ditches and how the exclusions for 

ditches were revised and clarified for the final rule.

Wyoming Water Development Commission (Doc. #17059)

8.54 Tributaries are defined to have a bed, a channel, and an ordinary high water mark. The 

fact that water is not required to be present with any frequency seems counter intuitive 

because the intent of the CWA is to regulate pollutant discharges into streams and rivers.

In an arid state such as Wyoming, most of the terrain is marked by dry channels that only 

flow water during periods of intense rainfall or melting snow. To propose that "navigable 
Clean Water Rule Response to Comments – Topic 8: Tributaries

55

waters" are to now include dry channels with a bed, channel and ordinary high water 

mark which resulted from an intense thunderstorm several years in the past defies logic. 

(p. 1-2)

Agency Response: See summary response for sections 8.1, 8.1.1 and 8.4. Section 

VII of the Technical Support Document discuss the science supporting the agencies’ 

determination that waters meeting the definition of “tributary” in the final rule 

have a significant nexus because they significantly affect the chemical, physical, and 

biological integrity of traditional navigable waters, interstate waters, and the 

territorial seas.

Indiana Cast Metals Association (Doc. #14895.1)

8.55 In defining a tributary as a drainage feature having a bed, bank and an ordinary high 

water mark (OHWM), the agencies want the public to believe that the assertion of CWA 

authority over “tributaries” is appropriate. This assertion fails to recognize the 

unnecessary inclusion of numerous other land features that fall within the definition of 

“tributary,” such as those areas with drainage features that do not even resemble any 

stream, brook or creek. Instead, the agencies advance new jurisdictional authority by 

introducing ambiguity and vague concepts of connectivity. (p. 2)

Agency Response: See summary response for section 8.1. Section II of the 

Technical Support Document describes the agencies’ significant nexus analysis, 

which includes discussions on “connectivity.”

Golf Course Superintendents Association of America et al. (Doc. #14902)

8.56 The proposed rule’s “tributary” definition vastly expands the scope of features that are 

currently regulated as tributaries, extending jurisdiction to features like ephemeral 

drainages, irrigation and ornamental ponds, and stormwater conveyances (like nonwetland swales) that contribute to flow. These have not been and should not be

jurisdictional. Conveyances that were once not jurisdictional may not provide ecological 

value and should not be regulated. This only adds to the permitting burden for 

landowners and regulatory agencies. (p. 13)

Agency Response: See summary response for section 8.1. Paragraph (b) of the 

final rule excludes many features. See section IV(I) of the preamble to the final rule 

and summary responses in Compendium 7 of this RTC, “Features and Waters Not 

Jurisdictional,” for a broad discussion of the final rule’s exclusions.

Institute of Scrap Recycling Industries, Inc. (Doc. #15041)

8.57 Taken as a whole, the subdefinition of “Tributary” also arguably allows for the possibility 

that a tributary could be “man-made” and could “lack a bed and banks or ordinary high 

water mark[] if [it] contribute[s] flow, either directly or through another water to a water 

identified in [the first three inclusions] of this definition”. That possibility could 

conceivably allow pipes and storm sewers to be tributaries and thus “waters of the U.S.” 

by the fifth inclusion and would effectively render the proposed definition unclear and its 

applicability uncertain. (p. 7)
Clean Water Rule Response to Comments – Topic 8: Tributaries

56

Agency Response: See summary response for section 8.1. Paragraph (b) of the 

final rule excludes many features. See section IV(I) of the preamble to the final rule 

and summary responses in Compendium 7 of this RTC, “Features and Waters Not 

Jurisdictional,” for a broad discussion of the final rule’s exclusions.

National Association of Manufacturers (Doc. #15410)

8.58 Beyond being inconsistent with the holding of Rapanos, the proposed rule’s definition of 

tributary is also arbitrary and capricious because it is based on the erroneous assumption 

that all “tributaries,” as broadly defined, have a “significant nexus” to traditional 

navigable waters—an assumption that is fundamentally inconsistent with the “significant 

nexus” test used to define “other waters,” which, as proposed, is a multi-factored, caseby-case test that recognizes, for example, that the distance between the water-in-question 

and a traditional navigable water is highly relevant to whether there is a “significant 

nexus.” 79 Fed. Reg. at 22214.

Yet the factors found by the proposed rule to define “significant nexus” are entirely 

ignored when it comes to defining “tributaries” even though the agencies purport to be 

basing their definition of “tributaries” on the “significant nexus” standard. The proposed 

rule classifies all “tributaries” as “navigable waters” even when they would not, in fact, 

satisfy the very “significant nexus” definition that the agencies are now proposing. 

Having found the controlling legal issue—“significant nexus”—requires a fact-intensive, 

case-by-case analysis, the agencies cannot simply decree that relevant variations in 

individual tributaries can be ignored because it analyzes these landform features in 

aggregate. See Business Roundtable v. SEC, 647 F.3d 1144, 1153 (D.C. Cir. 2011) 

(vacating agency action as “arbitrary” because it was “internally inconsistent”); Gen. 

Chem. Corp. v. United States, 817 F.2d 844, 846 (D.C. Cir. 1987) (vacating agency 

action as “arbitrary and capricious” because it was “internally inconsistent and 

inadequately explained”).

Certainly, at a minimum, the agencies cannot just assert that all tributaries have a 

“significant nexus” without explaining how that “significant nexus” is determined. Even 

if all tributaries individually have some impact on downstream water quality, that does 

not mean the impact is significant. An agency cannot simply declare a standard is 

satisfied without even explaining what the standard is—in such circumstances, there can 

be no reasoned basis for its decision. See Motor Vehicle Mfrs. Ass’n, 463 U.S. at 43; Int’l 

Union, UAW v. NRLB, 514 F.3d 574, 583 (6th Cir. 2008); U.S. Tel. Ass’n v. FCC, 188 

F.3d 521, 526 (D.C. Cir. 1999). (p. 16)

Agency Response: Section VII of the Technical Support Document discuss the 

science supporting the agencies’ determination that waters meeting the definition of 

“tributary” in the final rule have a significant nexus because they significantly affect 

the chemical, physical, and biological integrity of traditional navigable waters, 

interstate waters, and the territorial seas. Section II of the Technical Support 

Document describes the agencies’ significant nexus analysis, and Section I describes 

the legal basis of the final rule, including its consistency with the statute and case 

law.
Clean Water Rule Response to Comments – Topic 8: Tributaries

57

Texas Chemical Council (Doc. #15433)

8.59 As written, the proposed definition would include features on land that do not necessarily 

have a continuous surface hydrological connection to a traditional navigable water. It is 

conceivable that an EPA or Corps employee could determine on their own and without 

additional scrutiny, whether a bed and bank, or an ordinary high water mark, exists. 

Locating and utilizing the ordinary high water mark as a demarcation point for 

jurisdictional purposes presents a number of complications, including the lack of 

adequate notice to the public upon whom jurisdiction will be exercised.

In considering the potential enforcement actions that are furnished by the CWA, 

including civil judicial enforcement, civil administrative enforcement, criminal 

enforcement, and citizen suits, it is absolutely imperative that the public have adequate 

notice of what waters are considered jurisdictional.

Additionally, the proposed rule is too light regarding specific temporal and geographic

limits related to tributaries. First, there are no limitations on whether or how often water 

needs to be present in the “tributary.” For example, tributary streams could appear no 

more than once every 10 years under this definition. Additionally, there are no 

geographical or distance limitations regarding how far a tributary can be located from a 

traditional navigable waterway to constitute a jurisdictional water. EPA is proposing to 

use the “significant nexus” test as defining which waters are jurisdictional, and therefore 

need to tie specific limitations to tributaries that in fact represent a significant nexus. (p. 

5-6)

Agency Response: See summary responses in sections 8.1, 8.1.2, 8.2 and 8.4. 

Concerns regarding “due process” as it pertains to similarly situated waters within 

a region are addressed in the Technical Support Document.

GBMC & Associates (Doc. #15770)

8.60 2. The agencies (USACE and EPA) note in the Supplementary Information that "...the 

scope of the regulatory jurisdiction in this proposed rule is narrower than that under the 

existing regulations." In addition much of the rhetoric from EPA in their public meetings 

and webcasts on this subject have indicated that this proposed rule is only a clarification 

and that no new waters would be considered jurisdictional under the proposed rule, than 

are currently considered jurisdictional. It is difficult to see how this could be accurate. It 

appears as though the agencies have maintained their current concept of a "significant 

nexus" to a traditionally navigable water (TNW) being necessary to a finding that a water 

is a water of the US (WOUS) and jurisdictional under Section 404 of the Act. The 

proposed rule makes this claim in several locations but none better than where it states 

that "...a significant nexus is touchstone for CWA jurisdiction." (Sec.III.G.1.) However, 

the proposed rule goes through great effort to show that all tributaries, no matter their 

size, form, function or distance from a TNW have a significant nexus to the TNW and are 

by definition jurisdictional (Sec III.F). The agencies also state on several occasions that 

this is consistent with Rapanos ruling (Sec. III.F.3.) However, after the Rapanos decision 

the USACE and EPA issued a memorandum Regarding Clean Water Act Jurisdiction 

Following Rapanos v. United States and guidance entitled US Army Corps of Engineers 

Jurisdictional Determination Form Instructional Guidebook. These documents state that 
Clean Water Rule Response to Comments – Topic 8: Tributaries

58

the "...agencies will assert jurisdiction over the following categories of water bodies: 

TNWs; all wetlands adjacent to TNWs; non-navigable tributaries of TNWs that are 

relatively permanent (i.e. tributaries that typically flow year-round or have continuous 

flow at least seasonally); and wetlands that directly about such tributaries. In addition, the 

agencies' will assert jurisdiction over every water body that is not an RPW if that water 

body is determined (on the basis of fact specific analysis) to have a significant nexus with 

a TNW."11 The agencies' own guidance at that point in time limits their authority, and 

clearly indicates that not all tributaries would be considered jurisdictional. Now, under 

the proposed rule all tributaries that meet the definition of tributary (defined bed and 

banks with ordinary high water (OHW) features) would be jurisdictional water no mater 

its size. We request that the agencies re-evaluate their definition of significant nexus, 

clarify what constitutes a tributary and explain how the Rapanos decision supports their 

conclusion that all tributaries have a significant nexus to TNW in their response to these 

comments. (p. 1-2)

Agency Response: Section VII of the Technical Support Document discuss the 

science supporting the agencies’ determination that waters meeting the definition of 

“tributary” in the final rule have a significant nexus because they significantly affect 

the chemical, physical, and biological integrity of traditional navigable waters, 

interstate waters, and the territorial seas. Section I of the Technical Support 

Document describes the legal basis of the final rule, and also includes a summary of 

the historic scope of the existing regulatory definition of “waters of the United 

States.”

Federal Water Quality Coalition (Doc. #15822.1)

8.61 The proposed rule expands jurisdiction over this category of water by proposing to define 

tributaries to include features on the land where an EPA or Corps employee believes he 

or she can discern a bed, bank, and ordinary high water mark (OHWM), even if these 

features disappear underground, as long as these features can be identified upstream of 

where they disappear.3 And even these features would not be required for a wetland, 

lake, or pond to qualify as a tributary. A tributary would include wetlands and manmade 

conveyances. A tributary must contribute flow to a navigable or interstate water or 

territorial sea, but there are no temporal limits on how often a tributary contributes such 

flow. It could take years, decades, or even centuries for flow to reach a navigable water. 

There also are no geographic limits on how distant the flow that is per se jurisdictional is 

from navigable water and no need to show that the flow could carry pollutants to 

navigable water. Finally, given the fact that a tributary that disappears remains a 

tributary, it appears that the flow can be contributed through groundwater, which can take 

centuries to recharge to surface water.12 (p. 10)

Agency Response: See summary responses for sections 8.1 and 8.2. Section VII of 

the Technical Support Document discuss the science supporting the agencies’ 

 

11 RPW is "relatively permanent water". The concept came out of the Rapanos ruling

12 Nadeau, T. L., and M. C. Rains, Hydrological connectivity of headwaters to downstream waters: Introduction to 

the featured collection. Journal of the American Water Resources Association 43:1-4 (2007), at 126 (a survey article 

cited in the Draft Connectivity Report).
Clean Water Rule Response to Comments – Topic 8: Tributaries

59

determination that waters meeting the definition of “tributary” in the final rule 

have a significant nexus because they significantly affect the chemical, physical, and 

biological integrity of traditional navigable waters, interstate waters, and the 

territorial seas. See summary response 8.3 below for discussion of how breaks in 

OHWM are addressed. See summary response in Compendium 7.3.6 for discussion 

of the exclusion for groundwater. 

8.62 3. Evolution of the expansion of “tributary” jurisdiction.

The agencies did not originally assert jurisdiction under the CWA over ephemeral water 

features. In fact, their assertion of authority over ephemeral water is relatively recent. In 

1975, the preamble to the Corps’ interim final regulations specified that the upstream 

limit of jurisdiction is the headwaters, or point where average annual stream flow is five 

cubic feet per second.13 In 1977, the preamble to the final Corps regulations specified that 

jurisdiction extends to the entire surface tributary system.14 In 1994, the Corps Baltimore 

District issued a guidance letter specifying that ephemeral waters act as rain gutters, 

conveying water for a brief period of time following rain events. As such, they do not 

ordinarily develop an ordinary high water mark that would indicate they are part of a 

tributary system. Consequently, they were not regulated.15 However, in 2000, the Corps 

Nationwide Permits preamble specified that federal jurisdiction extends to ephemeral 

streams, provided they have an ordinary high water mark, overturning the Baltimore 

District’s presumption that ephemeral streams would not have an ordinary high water 

mark.16 This assertion of jurisdiction led to abuses.17 Moreover, even though the Corps 

took this position in 2000, as discussed below, both the plurality and Justice Kennedy 

were not persuaded that an ordinary high water mark is a basis for jurisdiction.

The agencies also did not assert authority over ditches until relatively recently. In fact, 

the 1977 Corps definition of waters of the U.S. expressly excluded “manmade nontidal 

drainage and irrigation ditches excavated on dry land” from the definition of tributaries, 

stating that they “are not considered waters of the United States under this definition.” 33 

C.F.R. § 323.2(a)(3)(1977).18

 

13 40 Fed. Reg. 31,320, 31,321 (July 25, 1975).

14 42 Fed. Reg. at 37,129.

15 Branch Guidance Letter, COE, Baltimore District, CENAB-OP-R, No.95-01, Oct. 17, 1994 (“Project Managers

are frequently required to determine the upstream limits of regulatory jurisdiction, including differentiating between

intermittent streams, which are regulated (33 CFR § 328.3(a)(3)), and ephemeral streams, which are not regulated.”)

(attached). This has been relied upon by numerous entities. See attached Montgomery County, MD guidance.

16 65 Fed. Reg. 12,818, 12,823 (Mar. 9, 2000).

17 For example, in a March 30, 2004, hearing of the Water Resources and Environment Subcommittee of the House

Committee on Transportation and Infrastructure on “Inconsistent Regulation of Wetlands and Other Water,” one 

witness testified that a Corps official used a 25-year old skidder rut to connect a wetland to a ditch to a stream.

House Doc. No. 108-58 at 81-82 (attached). Under the proposed rule, Corps officials would remain free to conclude 

that a skidder rut has an OHWM and therefore is part of the tributary system.

18 “We have adopted the suggestion of many commenters that we incorporate into our definition (and not in the

Preamble as we did in 1975) the statement that nontidal drainage and irrigation ditches that feed into navigable 

waters will not be considered ‘waters of the United States’ under this definition. To the extent that these activities 

cause water quality problems, they will be handled under other programs of the FWPCA, including Sections 208 and 

402.” 42 Fed. Reg. at 37127. Even though the preamble stated that the regulations were merely reorganized, the
Clean Water Rule Response to Comments – Topic 8: Tributaries

60

In addition, the agencies have not traditionally asserted jurisdiction over water based on 

subsurface connections that are not diversions of former surface streams and have never 

done so categorically.19 For example, a 2001 policy issued by the Galveston District of 

the Corps of Engineers states that it does not use groundwater connections to establish 

jurisdiction.20 Moreover, directly contradicting the position in the proposed rule, in 

litigation, EPA has taken the position that identification of a connection to surface water 

via groundwater must be made on a site-specific basis.

21

Yet the agencies now claim that all waters proposed to be defined as “tributaries,” 

including ephemeral waters, ditches, and waters with subsurface connections, have a 

“significant nexus” to navigable or interstate waters or the territorial sea and therefore are 

per se jurisdictional. This is an expansion of jurisdiction.

This proposed expansion of the definition of tributary has created tremendous uncertainty 

regarding the status of land that exhibits erosion features from wind or water even if dry 

for many years, the status of water conveyance systems, the status of water drainage 

systems, the status of ephemeral streams, and the status of features that have no 

continuous surface connection to navigable water. (p. 12-13)

Agency Response: See summary responses for sections 8.1 and 8.1.1. See 

summary responses for the Ditches Sections 6.0 and 6.2 for a focused description of 

ditches, the regulatory history of ditches and how the exclusions for ditches were 

revised and clarified for the final rule. Section VII of the Technical Support 

Document discuss the science supporting the agencies’ determination that waters 

meeting the definition of “tributary” in the final rule have a significant nexus 

because they significantly affect the chemical, physical, and biological integrity of 

traditional navigable waters, interstate waters, and the territorial seas. Section I of 

the Technical Support Document describes the legal basis of the final rule, and also 

includes a summary of the historic scope of the existing regulatory definition of 

“waters of the United States.”

Water Advocacy Coalition (Doc. #17921.1)

8.63 By its terms, the proposed rule expands CWA jurisdiction to ephemeral drainages, 

ditches (including roadside, flood control, irrigation, stormwater, railroad right-of-way, 

and agricultural ditches), waters in riparian and floodplain areas, industrial ponds, and 

isolated waters that have not previously been regulated as “waters of the United States.” 

(p. 14) 

 

1986 definition of waters of the U.S. moved this clarification from rule language to preamble language and reserved 

the right to regulate ditches on a case by case basis. 51 Fed. Reg. at 41217.

19 Waters and Wetlands, Corps of Engineers Needs to Evaluate Its District Office Practices in Determining

Jurisdiction (GAO-04-297), at 24 (discussing using connections through subsurface closed conveyances to establish 

jurisdiction only if the pipe replaced a historic stream) (attached). No such limitation appears in the proposed rule.

20 Adjacent/Isolated Criteria, Galveston District Policy Number 01-001 (attached).

21 Conservation Law Foundation et al. v U.S. EPA, et. al., Case No. 1:10-cv-11455-MLW, Memorandum in Support 

of Defendants’ Motion for Summary Judgment, at 20-21 (noting that a hydrological connection to surface water via 

groundwater is a site-specific determination) (attached).
Clean Water Rule Response to Comments – Topic 8: Tributaries

61

Agency Response: Paragraph (b) of the final rule excludes many features. See 

section IV(I) of the preamble to the final rule and summary responses in 

Compendium 7 of this RTC, “Features and Waters Not Jurisdictional,” for a broad 

discussion of the final rule’s exclusions. Sections IV(F) and IV(G) of the preamble 

discusses the revisions and clarifications of “tributaries” and “adjacent waters,” 

respectively.

8.64 This definition allows for regulation of ephemeral drainages, ditches, and conveyances, 

including stormwater conveyances, that are not currently treated as “waters of the United 

States.” The agencies’ determination that these features, many of which may flow for 

only a few hours or days following a rain event, categorically have a significant nexus is 

not supported by science. As explained in the GEI Report, “all tributaries . . . exist on a 

gradient of connectivity, and the science has not identified the point on that gradient (i.e., 

the strength of connectivity) where the significant nexus falls.”22 The studies cited by the 

agencies “largely fail to assess the significance of connectivity,” and therefore “the 

existing scientific literature and analyses presented by EPA do not support these 

categorical jurisdictional determinations.” Id. 

...

Ephemeral drainages, for example, should not be per se jurisdictional. Although they 

may exhibit a bed, bank, and OHWM, ephemeral drainages only flow in response to 

precipitation events, which in some parts of the country only occur occasionally during a 

portion of the wet season. In particular, the arid West is covered with dry washes, 

arroyos, seasonal waterbodies, and ephemeral drainages. Rarely can a development 

project or industrial facility be constructed without affecting one or more of these 

ubiquitous features. Many stormwater conveyances are constructed to prevent 

degradation of downstream waters and should not become a source of regulatory burden 

for property owners. Ephemeral drainages were historically outside CWA jurisdiction,23

and for good reason – they flow only rarely, and even more rarely in quantities that could 

affect other more permanent or significant waterbodies.24 Indeed, the science does not 

demonstrate that treating ephemeral features as waters of the United States will have 

benefits for downstream waters. As Dr. Michael Josselyn notes, “These low order 

features may have flow for only a few hours or days following storm events and are the 

most likely candidates for being on the low end of the [connectivity] gradient. . . . .”25

These are not features with significant effects on downstream navigable waters. The State 

of Missouri, for instance, determined, based on a U.S. Geological Survey (“USGS”) 

analysis, that data did not exist to support a significant connection between ephemeral 

 

22 GEI Report, Exhibit 6 at 4.

23 Even the 2008 Rapanos Guidance, which is still in effect, requires “continuous flow at least seasonally (e.g., 

typically three months).” Rapanos Guidance at 5-6 (emphasis added). The agencies have failed to explain this 

change.

24 In fact, the reasons cited by the agencies for not regulating puddles are similarly applicable for ephemeral 

drainages. The preamble states that a puddle, which “forms . . . immediately after a rainstorm,” “cannot reasonably 

be considered a water body or aquatic feature at all, because usually it exists for only a brief period of time before 

the water in the puddle evaporates or sinks into the ground.” 79 Fed. Reg. at 22,218. Such is the case with ephemeral 

drainages.

25 SAB Panel Member Comments, Exhibit 7 at 42 (comments of Dr. Michael Josselyn).
Clean Water Rule Response to Comments – Topic 8: Tributaries

62

streams and aquatic uses.26 Accordingly, the State of Missouri (with EPA approval) 

determined that it would not set water quality standards for certain ephemeral streams.27

Similarly, if ephemeral drainages are now jurisdictional “waters of the United States,” as 

proposed, Kansas estimates a more than four-fold increase from 32,000 miles of streams 

to 134,000 miles of streams that will be “waters of the United States” and therefore 

subject to water quality standards.28 Neither the Connectivity Report nor Appendix A of 

the preamble demonstrates that ephemeral features have significant chemical, physical 

and biological effects on TNWs. Instead, the agencies have not assessed the significance 

of these connections and have ignored the caution from the SAB Panel that “temporal and 

spatial predictability of connectivity is especially important to quantify when assessing 

potential for downgradient effects in systems without permanent or continuous 

flowpaths.”29 Dr. Michael Josselyn of the SAB Panel notes that “the science needs to be 

more substantial than currently demonstrated in the Draft Science Report” for the 

agencies to assert jurisdiction over ephemeral drainages.30 Indeed, these “very small 

drainages” “are not usually considered in the scientific studies that deal with headwater 

streams,” and the agencies should recognize the “uncertainty and limits of the scientific 

knowledge” with respect to these features.31 As Dr. Mark Murphy of the SAB Panel 

observed, “inclusion by rule of all ephemeral tributaries, ‘regardless of size or flow 

duration,’ is not scientifically justified.”32 Furthermore, by asserting jurisdiction over 

such attenuated waters and potentially wet features, the agencies will misuse their limited 

resources and the limited resources of the States and regulated community. For all these 

reasons, ephemeral drainages should not be considered “waters of the United States.” 

...

Asserting categorical jurisdiction over all features covered by the proposed “tributary” 

definition would result in huge land areas, in all parts of the country, becoming subject to 

federal control. For an illustration of the reach of the proposed rule’s “tributary” 

definition, one need look no further than the EPA maps, released to the public by Rep. 

Lamar Smith and the U.S. House of Representatives Committee on Science, Space, and 

Technology, that rely on USGS data and appear to depict the scope of CWA 

jurisdiction.33 These maps indicate a total of approximately 8.1 million miles of 

 

26 See Missouri Department of Natural Resources, Regulatory Impact Report In Preparation for Proposing An 

Amendment to 10 CSR 20-7.031, Missouri Water Quality Standards at 4, 25 (Nov. 9, 2012), available at 

http://www.dnr.mo.gov/env/wpp/docs/master-rir-wqs-112312.pdf (Based on USGS study, “A Gap Analysis for 

Riverine Ecosystems of Missouri” (2005), Missouri decided to designate all perennial rivers and streams, 

intermittent streams with permanent pools, and those waters spatially represented by the 1:100,000 scale NHD, but 

not ephemeral waters.)

27 See Mo. Code Reg. Ann. tit. 10, § 20-7.031.

28 See Presentation of Mike Tate and Tom Stiles, Kansas Department of Health and Environment, Waters of the U.S. 

(May 2, 2014) ( attached hereto as Exhibit 9) at 11-12 (map of currently designated “Waters of the United States” in 

Kansas and map of additional “waters of the United States” in Kansas if ephemerals are added).

29 SAB Panel Review of Connectivity Report, Exhibit 5 at 15.

30 SAB Panel Member Comments, Exhibit 7 at 42 (comments of Dr. Michael Josselyn).

31 See id.

32 Id. at 99 (comments of Dr. Mark Murphy).

33 See EPA State and National Maps of Waters and Wetlands, available at http://science.house.gov/epamaps-state2013#overlay-context. (last visited Oct. 29, 2014).
Clean Water Rule Response to Comments – Topic 8: Tributaries

63

perennial, intermittent, and ephemeral streams across the 50 States, all of which would be 

categorically regulated as tributaries under the proposed rule.34 Unfortunately, these maps 

are just the tip of the iceberg, as they depict only a fraction of the land and waters that 

would be “tributaries” subject to federal CWA jurisdiction because they do not depict 

ditches and other manmade conveyances that would be categorically jurisdictional 

tributaries under the proposed rule. The agencies go too far in asserting such broad 

jurisdiction over tributaries without legal or scientific support. (p. 43-46, 47)

Agency Response: See section IV(I) of the preamble to the final rule and 

summary responses in Compendium 7 of this RTC, “Features and Waters Not 

Jurisdictional,” for a broad discussion of the final rule’s exclusions. Section III(C) 

of the preamble and Section VII of the Technical Support Document discuss the 

science supporting the agencies’ determination that waters meeting the definition of 

“tributary” in the final rule have a significant nexus because they significantly affect 

the chemical, physical, and biological integrity of traditional navigable waters, 

interstate waters, and the territorial seas. See also Section 9 “Scientific Evidence 

Supporting the Rule” of the Response to Comments. Section I of the Technical 

Support Document describes the legal basis of the final rule, and also includes a 

summary of the historic scope of the existing regulatory definition of “waters of the 

United States.” The agencies do not have maps illustrating the extent of 

jurisdictional waters of the United States. Determining the jurisdictional status of a 

water feature often requires site specific knowledge. Although the final rule 

provides increased clarity and “bright line” distinctions to help differentiate waters 

of the United States from non-jurisdictional features, it will not eliminate the need 

for consideration of site specific knowledge. The agencies generally only conduct 

jurisdictional determinations at the request of individual landowners, thus we do 

not have maps depicting the geographic scope of the CWA. Such maps do not exist 

and the costs associated with a national effort to develop them are cost prohibitive 

and would require access to private property across the country. The U.S. 

Geological Survey and the U.S. Fish and Wildlife Service collect information on the 

extent and location of water resources across the country and use this information 

for many non-regulatory purposes, including characterizing the national status and 

trends of wetlands losses. This data is publicly available and the agencies have 

relied on USGS and USFWS information to characterize qualitatively the location 

and types of national water resources. This information is depicted on maps but not 

for purposes of quantifying the extent of waters covered under CWA regulatory 

programs.

 

34 In a blog post, EPA states that these maps “do not show the scope of waters . . . proposed to be covered under 

EPA’s proposed rule” and “cannot be used to determine Clean Water Act jurisdiction – now or ever.” Tom 

Reynolds, Mapping the Truth, EPA Connect Blog (Aug. 28, 2014), 

http://blog.epa.gov/epaconnect/2014/08/mapping-the-truth/. But why not? The proposed rule indicates that the 

agencies intend to treat all perennial, intermittent, and ephemeral streams as per se jurisdictional (no case-specific 

analysis), and the preamble suggests that the agencies will identify tributaries using USGS maps and other 

appropriate information. 79 Fed. Reg. at 22,202. How, then, can the agencies claim that these maps do not show the 

scope of streams subject to federal CWA jurisdiction under the proposed rule?
Clean Water Rule Response to Comments – Topic 8: Tributaries

64

8.65 B. The Proposed Rule’s Treatment of Tributaries Is Not Supported by Science and 

Will Result in Confusion in the Field.

One of the most problematic aspects of the proposed rule is how the agencies propose to 

regulate tributaries. As we have noted in previous comments, the regulation of 

“tributaries” has caused longstanding problems.35 The proposed rule categorically 

determines that tributaries, regardless of size or significance, have a significant nexus to 

TNWs, interstate waters, and the territorial seas. 79 Fed. Reg. at 22,201. Thus, any water 

that meets the rule’s broad definition of “tributary” will be a jurisdictional “water of the 

United States.” Id. And waters and wetlands adjacent to tributaries will be automatically 

jurisdictional. Id. at 22,263. As explained in the Appendix to these comments, the 

proposed rule’s categorical regulation of all channelized features with an ordinary high 

water mark (“OHWM”) and flow is contrary to the limits of CWA jurisdiction 

recognized by the plurality and Justice Kennedy in Rapanos. In addition to these legal 

concerns, the proposed treatment of tributaries is overbroad and would extend jurisdiction 

to many features that the agencies have not previously regulated. Equally troubling, the 

proposed definition of “tributary” is vague and confusing, and will likely lead to 

inconsistent application in the field.

...

Instead of categorically regulating all channels, canals, and ditches, and then trying to 

exempt particular features such as stormwater conveyances, the agencies should identify 

a new standard for tributaries that is based on scientific evidence and covers only 

traditionally understood tributaries that either themselves qualify as TNWs or have the 

requisite relationship under Supreme Court limits with TNWs. Constructed stormwater, 

process water, and wastewater conveyances (swales, channels, ditches, and 

detention/retention ponds), excavated or otherwise constructed as part of site 

development projects, agricultural fields, or other sites, should not be treated as 

jurisdictional “waters of the United States.” (p. 43, 49)

Agency Response: Section III of the preamble and Section VII of the Technical 

Support Document discuss the science supporting the agencies’ determination that 

waters meeting the definition of “tributary” in the final rule have a significant nexus 

because they significantly affect the chemical, physical, and biological integrity of 

traditional navigable waters, interstate waters, and the territorial seas. Section I of 

the Technical Support Document describes the legal basis of the final rule, including 

its consistency with the statute and case law. Paragraph (b) of the final rule 

excludes many features, including most ditches that are not relocated tributaries or 

excavated in tributaries, erosional features that do not meet the definition of 

“tributary,” waste treatment systems designed to meet the requirements of the 

CWA and stormwater control features created in dry land. See summary responses 

in Compendium 7 of this RTC, “Features and Waters Not Jurisdictional,” for a 

broad discussion of the final rule’s exclusions and Compendium 6, Section 6.2 of this 

 

35 See WAC Comments on 2011 Draft Rule, Exhibit 1 at 61-62; AFBF Comments on 2008 Rapanos Guidance, 

Exhibit 2 at 73-75; FEEP Comments on 2003 ANPRM, Exhibit 3 at 20-21.
Clean Water Rule Response to Comments – Topic 8: Tributaries

65

RTC, “Excluded Ditches,” for a more focused discussion on the revisions and 

clarifications of the ditch exclusions. 

American Society of Civil Engineers (Doc. #19572)

8.66 EPA and USACE propose definitions for a number of critical terms used in the proposed 

rule. We provide the following examples and comments of definitions that are too broad 

in scope, ambiguous or may require additional revisions.

Tributary: The proposed definition of tributary is too broadly defined. In the proposed 

rule a tributary is characterized by a bed, bank and ordinary high water mark which 

contributes flow directly or through other water bodies to a “water of the U.S.”36 The 

proposed rule states that a tributary does not lose its status if there are man-made breaks 

(such as bridges, culverts, pipes, dams) so long as a bed, bank and ordinary high water 

mark can be identified up and downstream of the break. Importantly, a tributary can be a 

natural, man-altered, or man-made and includes rivers, streams, lakes, impoundment, 

canals and ditches (unless excluded). Our members have expressed particular concern 

that, broadly read, the rule may significantly impact municipalities who manage local 

streets that could be considered jurisdictional under proposed definition. Taken to the 

extreme, the question has been posed: are rain gutters subject to jurisdiction? ASCE urges 

EPA and USACE to consider adding exemptions and clarifications to this definition. (p. 

7-8)

Agency Response: See summary response for section 8.1. Paragraph (b) of the 

final rule excludes many features, including most ditches that are not relocated 

tributaries or excavated in tributaries, erosional features that do not meet the 

definition of “tributary” and stormwater control features created in dry land. See 

summary responses in Compendium 7 of this RTC, “Features and Waters Not 

Jurisdictional,” for a broad discussion of the final rule’s exclusions and 

Compendium 6, Section 6.2 of this RTC, “Excluded Ditches,” for a more focused 

discussion on the revisions and clarifications of the ditch exclusions. As stated in the 

preamble to the final rule, curbs and gutters have never been considered “waters of 

the United States.”

Minnkota Power Cooperative, Inc. (Doc. #19607)

8.67 The expanded definition of a tributary in this Proposed Rule seeks to expand CWA 

jurisdiction to potentially include any channelized feature, such as a ditch, ephemeral 

drainages, storm water conveyances, wetlands, ponds, impoundments, erosional features, 

etc. that directly or indirectly may contribute water flow to a navigable water, 

disregarding frequency or duration of flow. (p. 2)

Agency Response: See summary response for section 8.1. Paragraph (b) of the 

final rule excludes many features, including most ditches that are not relocated 

tributaries or excavated in tributaries, erosional features that do not meet the 

definition of “tributary” and stormwater control features created in dry land. See 

summary responses in Compendium 7 of this RTC, “Features and Waters Not 

 

36 See Definition of “Waters of the United States” Under the Clean Water Act; Proposed Rule, 79 Fed. Reg. 22, 201.
Clean Water Rule Response to Comments – Topic 8: Tributaries

66

Jurisdictional,” for a broad discussion of the final rule’s exclusions and 

Compendium 6, Section 6.2 of this RTC, “Excluded Ditches,” for a more focused 

discussion on the revisions and clarifications of the ditch exclusions.

Kerr Environmental Services Corps. (Doc. #7937.1)

8.68 The "Jurisdictional Determination Form Instructional Guidebook" prepared jointly by the 

USEPA and USACE (May 30, 2007) as a means of interpreting the Rapanos decision 

indicates that: "Tributary is a natural man-altered, or man-made water body. Examples 

include Rivers, streams and lakes that flow directly or indirectly into TNWs." 

We recommend the proposed rule adopt the standard used in the Guidebook. The 

proposed definition as written is far too vague and broad will undermine clarity and 

predictability and is contrary to congressional intent and court-precedent. (p. 8)

Agency Response: The agencies disagree and believe instead that the revised 

definition of “tributary” in the final rule, together with the revised and clarified 

exclusions under paragraph (b), will limit jurisdiction to only those waters that have 

a significant nexus to traditional navigable waters, interstate waters, and the 

territorial seas. See summary response for section 8.1. 

Kansas Independent Oil & Gas Association (Doc. #12249)

8.69 There is no language in the proposal that would provide for any limit as to which 

tributaries (and most ditches) are part of the "navigable waters" as contemplated by 

Congress. Quite the contrary, the definition of "tributary" and the preamble discussion go 

to great lengths to explain away potential distinctions that would result in a less inclusive 

jurisdictional result. As proposed, all tributaries would become jurisdictional. Absent 

from the proposal or the docket is a clear assessment of whether this definition delivers a 

jurisdictional water that is based on a threat to "waters of the United States" that is more 

than speculative. The agencies' goal of "eliminating the need to make a case-specific 

determination for tributaries" is not a goal that is consistent with the Clean Water Act. (p. 

14)

Agency Response: The agencies disagree and believe instead that the revised 

definition of “tributary” in the final rule, together with the revised and clarified 

exclusions under paragraph (b), will limit jurisdiction to only those waters that have 

a significant nexus to traditional navigable waters, interstate waters, and the 

territorial seas. See summary response for section 8.1. Section III(C) of the 

preamble and Section VII of the Technical Support Document discuss the science 

supporting the agencies’ determination that waters meeting the definition of 

“tributary” have a significant nexus because they significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas. Paragraph (b) of the final rule excludes many features, 

including most ditches that are not relocated tributaries or excavated in tributaries. 

See summary responses in Compendium 7 of this RTC, “Features and Waters Not 

Jurisdictional,” for a broad discussion of the final rule’s exclusions and 

Compendium 6, Section 6.2 of this RTC, “Excluded Ditches,” for a more focused 

discussion on the revisions and clarifications of the ditch exclusions.
Clean Water Rule Response to Comments – Topic 8: Tributaries

67

Pennsylvania Coal Alliance (Doc. #13074)

8.70 The Proposed Rule broadens the definition of “waters of the United States” by revising 

the definitions and scope of tributaries... Under the Proposed Rule, all tributaries are 

categorically presumed to have a significant nexus to a traditional navigable water, 

interstate water or territorial sea. In contrast, under current guidance,37 jurisdiction over 

tributaries that are not relatively permanent is determined on a case-by-case basis. The 

Proposed Rule broadly defines tributary to include any water with a bed and banks and 

ordinary high water mark (OHWM), or any wetland, lake or pond, that contributes flow, 

either directly or indirectly to other jurisdictional waters. Ditches are only excluded from 

this definition in certain, narrow circumstances. (p. 3)

Agency Response: See summary response for section 8.1. Section III(C) of the 

preamble and Section VII of the Technical Support Document discuss the science 

supporting the agencies’ determination that waters meeting the definition of 

“tributary” have a significant nexus because they significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas. Paragraph (b) of the final rule excludes many features, 

including most ditches that are not relocated tributaries or excavated in tributaries. 

See summary responses in Compendium 7 of this RTC, “Features and Waters Not 

Jurisdictional,” for a broad discussion of the final rule’s exclusions and 

Compendium 6, Section 6.2 of this RTC, “Excluded Ditches,” for a more focused 

discussion on the revisions and clarifications of the ditch exclusions.

O'Neil LLP (Doc. #14651)

8.71 Tributary

The Proposed Rule's definition of the term "tributary" as any feature with a bed and bank 

that contributes flow to any water on the Proposed Rule's initial list of Waters of the 

United States allows for a far too broad potential application of the term, and thus a too 

broad definition of what the Agencies can regulate under the CWA. Many features -

particularly in large portions of the arid western United States, including many parts of 

California -- such as dry arroyos and mountain channels, have a bed and bank even 

though they only flow when it rains or the snow melts. Manmade ditches can also exhibit 

these features which the Proposed Rule would now define as a "tributary" to be regulated 

under the CWA. This new definition is too expansive, and significantly exceeds the limits 

of the agencies' authority to regulate "waters" under the language of the CWA. (p. 3)

Agency Response: See summary response for section 8.1. Paragraph (b) of the 

final rule excludes many features, including most ditches that are not relocated 

tributaries or excavated in tributaries. See summary responses in Compendium 7 of 

this RTC, “Features and Waters Not Jurisdictional,” for a broad discussion of the 

final rule’s exclusions and Compendium 6, Section 6.2 of this RTC, “Excluded 

 

37 At present, industry relies extensively on the December 2, 2008 guidance memorandum issued by the EPA and 

Corps (2008 Guidance) to interpret the meaning of “waters of the United States” under the CWA. “Clean Water Act 

Jurisdiction Following the U.S. Supreme Court’s Decision in Rapanos v. United States and Carabell v. United 

States,” (December 2, 2008).
Clean Water Rule Response to Comments – Topic 8: Tributaries

68

Ditches,” for a more focused discussion on the revisions and clarifications of the 

ditch exclusions.

West Valley Planned Communities (Doc. #18906)

8.72 A lake, pond, or other ornamental water feature in combination with drainage 

canals/washes could be considered a tributary and, thus, by rule "waters of the U.S." if it 

could contribute flow into a traditionally navigable or interstate water either directly or 

through a tributary. Recall, a tributary can be perennial, seasonal, or ephemeral. 

Consequently, as written, this rule would allow the EPA, Army Corps, or a citizen using 

the Citizen Suit provision, to assert that a lake, pond, other ornamental water feature, or 

drainage canal/wash is a tributary if during ephemeral flow conditions, i.e., seasonal 

flooding, water could flow through such water features into the Gila River or the 

Colorado River directly or through any other natural or manmade tributary.

Because this definition does not require a "significant nexus" finding, rather, by rule, a 

"significant nexus" is assumed and the burden is shifted from the EPA and Army Corps 

and placed onto the planned community to demonstrate a particular water feature does 

not have a "significant nexus" to downstream interstate or traditionally navigable water. 

This poses significant regulatory uncertainty, with the prospect of significant fines if the 

EPA or Army Corps determines that a particular water feature, i.e., anything from a 

stormwater drainage ditch to a lake on a golf course, is a "tributary" because it 

contributes flows, directly or even through a flood control canal owned by the flood 

control district, to an interstate or traditionally navigable water. Given the uncertainty and 

regulatory burden, the proposed definition of "tributary" must be abandoned. (p. 3-4) 

Agency Response: See summary response for section 8.1. Paragraph (b) of the 

final rule excludes many features, including stormwater control features created in 

dry land and most ditches that are not relocated tributaries or excavated in 

tributaries. See summary responses in Compendium 7 of this RTC, “Features and 

Waters Not Jurisdictional,” for a broad discussion of the final rule’s exclusions and 

Compendium 6, Section 6.2 of this RTC, “Excluded Ditches,” for a more focused 

discussion on the revisions and clarifications of the ditch exclusions.

CEMEX (Doc. #19470)

8.73 Contrary to the claims of the EPA and the Corps, the proposed rule will actually cause 

more confusion than clarity. The agencies "categorical" inclusion of all tributaries 

defined by an observed "mark" on the landscape and its regulation of wetlands and waters 

adjacent to tributaries based on vague "neighboring," "riparian," "floodplain" and 

"shallow subsurface" connection criteria makes it virtually impossible to know what 

areas are regulated and what areas are not. Adjacent waters cannot and should not 

arbitrarily be considered tributaries. (p. 2)

Agency Response: See summary response for section 8.1. Section III(C) of the 

preamble and Section VII of the Technical Support Document discuss the science 

supporting the agencies’ determination that waters meeting the definition of 

“tributary” have a significant nexus because they significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 
Clean Water Rule Response to Comments – Topic 8: Tributaries

69

and the territorial seas. Similarly, section IV(G) of the preamble and section VIII 

of the Technical Support Document discuss “adjacent waters.” 

National Association of Home Builders (Doc. #19540)

8.74 3. The Agencies have Expanded Clean Water Act Jurisdiction by Requiring only 

Three Geomorphic Traits to Meet the Tributary Definition.

According to the Agencies, a water must only have a bed, bank, and an OHWM and 

contribute flow, directly or indirectly, to a traditional navigable water, an interstate water, 

a territorial sea, or an impoundment to be a tributary. Any water meeting the tributary 

definition would be jurisdictional by rule. This definition is both significant and an 

unlawful expansion of the jurisdictional scope of the CWA, as it is overbroad and 

inconsistent with the Supreme Court's Rapanos ruling. In Rapanos, Justice Kennedy 

opined, "[T]he Corps deems a water a tributary if it feeds into a traditional navigable 

water (or a tributary thereof) and possesses an ordinary highwater mark . . .. [T]he 

breadth of this standard-which seems to leave wide room for regulation of drains, ditches, 

and streams remote from any navigable-in-fact water and carrying only minor water 

volumes toward it-precludes its adoption . . . ."38 He continued, "[T]he dissent would 

permit federal regulation whenever wetlands lie alongside a ditch or drain, however 

remote and insubstantial, that eventually may flow into traditional navigable waters. The 

deference owed to the Corps' interpretation of the statute does not extend so far."39

Justice Kennedy was not alone in his opinion regarding the limited jurisdiction that 

should be extended to tributaries. Justice Scalia, in his four-Justice plurality, wrote ". . . 

the Corps interpreted its own regulations to include 'ephemeral streams' and 'drainage 

ditches' as 'tributaries' that are part of the 'water of the United States,' see 33 CFR section 

328.3(a)(5), provided that they have a perceptible 'ordinary high water mark' . . . This 

interpretation extended 'the waters of the United States' to virtually any land feature over 

which rainwater or drainage passes and leaves a visible mark - even if only 'the presence 

of litter and debris.' 33 CFR section 328.3(e) . . . Prior to our decision in SWANCC, lower 

courts upheld the application of this expansive definition of 'tributaries' to such entities as 

storm sewers that contained flow to cover waters during heavy rainfall . . . and dry 

arroyos connected to remote waters through the flow of groundwater over 'centuries.’”40

Justice Scalia continued, "Even after SWANCC, the lower courts have continued to 

uphold the Corps' sweeping assertions of jurisdiction over ephemeral channels and drains 

as 'tributaries."'41 The Supreme Court has interpreted a definition of "tributary" based 

upon the presence of an OHWM as "expansive," yet the Agencies conveniently ignore 

this and publicly attest on their website,42 on official EPA blog posts,43 during outreach 

 

38 Rapanos, 547 U.S. at 781.

39 Id. at 778-779.

40 Id. at 725-726.

41 Id. at 726

42 See www.ena.zov/uswaters. Under the heading "What the Rule Does Not Do," we read, "Does not broaden

coverage of Clean Water Act" (last visited Nov. 6,2014); see also http:l/www2.eoa~ov/sites/nroductionlfiles/2014-

09/documents/facts about wotus.pdf, "The proposed rule does not expand jurisdiction [of the Clean Water Act]"

(last visited Nov. 6,2014)

43 In a blog post EPA Office of Water Acting Assistant Administrator Nancy Stoner, entitled "Setting the Record
Clean Water Rule Response to Comments – Topic 8: Tributaries

70

with stakeholder,44 in op-eds, 45 and in testimony at congressional hearings46 that the 

proposed rule does not broaden coverage of the CWA. This is simply not true. What's 

more, the Agencies cite no studies supporting the premise that the presence of an OHWM 

indicates a channel has sufficient flow to significantly impact the chemical, physical, and 

biological integrity of an (a)(l) through (4) water.

The Agencies consider ephemeral features to be tributaries and jurisdictional by rule 

provided they meet the tributary definition: "All tributary streams, including perennial, 

intermittent, and ephemeral streams, are physically and chemically connected to 

downstream traditional navigable waters, interstate waters, and the territorial seas . . ."47

The proposed rule continues, "The flow in the tributary may be ephemeral, intermittent or 

perennial . . ."48 Indeed, asserting categorical jurisdiction over ephemeral and intermittent 

flow is inconsistent with current regulatory guidance which states, '"[R]elatively 

permanent' waters do not include ephemeral tributaries which flow only in response to 

precipitation and intermittent streams which do not typically flow year-round or have 

continuous flow at least seasonally. However, CWA jurisdiction over these waters will be 

evaluated under the significant nexus standard . . . "49 By categorically asserting 

jurisdiction over ephemeral and intermittent streams on the purported basis that all 

tributaries have a significant nexus to downstream waters, the Agencies are sweeping in 

millions of miles of predominantly dry channels for which they are currently required to 

perform a significant nexus test. Indeed, of the nation's river miles reported on recent 

EPA maps developed by the U.S. Geological Survey, some 4.6 million miles of streams 

in the United States (77% of all mapped river and stream miles) are listed as ephemeral or 

intermittent.50 Expanding the tributary definition will undoubtedly expand the number of 

waters deemed under the jurisdiction of the CWA.

Equally problematic, the science does not demonstrate that treating ephemeral features as 

“waters of the United States” will have benefits for downstream waters. The state of 

Missouri, for instance, determined based on U.S. Geological Survey analysis, that it 

would not set water quality standards for ephemeral streams because data do not exist to 

support a significant connection to aquatic uses.51 Neither the draft Connectivity Report 

 

Straight on Waters of the US," she writes, "The, proposed rule does not expand jurisdiction [of the Clean Water

Act]." (June 30,2014) available at http://blog.epa.gov/epaconnect/2014/06/setting-the-record-straight-on-wous/

(last visited Nov. 6, 2014)

44 During a July 2014 stakeholder meeting with fanners in Missouri, EPA Administrator Gina McCarthy stated, "

you don't need a permit now you won't need one [under the proposed rule]."

45 See EPA Administrator Gina McCarthy's Huffington Post op-ed (March 25,2014) ("Some may think that this

rule will broaden the reach of EPA regulations -- but that's simply not the case. Our proposed rule will not add to or

expand the scope of waters historically protected under the Clean Water Act.") available at 

http://www.huffingtonpost.com/gina-mccarthy/cleaer-protections-for-c_b_5029328.html

46 In testimony before the House Committee on Science, Space and Technology on July 9, 2014, EPA Deputy 

Administrator Robert Perciasepe stated at 1:04:40: “We’re not expanding the jurisdiction of the Clean Water Act.”, 

available at http://www.c-span.org/video/?320360-1/hearing-clean-water-act-regulations

47 79 Fed. Reg. at 22,197 (emphasis added).

48 Id. at 22,202 (emphasis added)

49 2008 Rapanos Guidance at 7 (emphasis added).

50 See http://science.house.gov/epa-maps-state-2013#overlay-context

51 See Missouri Department of Natural Resources, Regulatory Impact Report In Preparation for Proposing An
Clean Water Rule Response to Comments – Topic 8: Tributaries

71

nor Appendix A of the preamble refute this decision, as they do not demonstrate that 

ephemeral features have significant chemical, physical, or biological effects on traditional 

navigable waters. For these reasons, ephemeral drainages should not automatically be 

considered "waters of the United States." (p. 58-60)

Agency Response: See summary response for section 8.1. Section III(C) of the 

preamble and Section VII of the Technical Support Document discuss the science 

supporting the agencies’ determination that waters meeting the definition of 

“tributary” have a significant nexus because they significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas. Section I of the Technical Support Document describes the 

legal basis of the final rule, including its consistency with the statute and case law. 

See summary response for section 8.1.1, “Relevance of Flow Regime.” Regulations 

addressing water quality standards for waters of the United States provide that 

states may modify standards for streams with natural ephemeral flow, but may not 

declare an ephemeral stream non-jurisdictional altogether. The agencies do not 

have maps illustrating the extent of jurisdictional waters of the United States. 

Determining the jurisdictional status of a water feature often requires site specific 

knowledge. Although the final rule provides increased clarity and “bright line” 

distinctions to help differentiate waters of the United States from non-jurisdictional 

features, it will not eliminate the need for consideration of site specific knowledge. 

The agencies generally only conduct jurisdictional determinations at the request of 

individual landowners, thus we do not have maps depicting the geographic scope of 

the CWA. Such maps do not exist and the costs associated with a national effort to 

develop them are cost prohibitive and would require access to private property 

across the country. The U.S. Geological Survey and the U.S. Fish and Wildlife 

Service collect information on the extent and location of water resources across the 

country and use this information for many non-regulatory purposes, including 

characterizing the national status and trends of wetlands losses. This data is 

publicly available and the agencies have relied on USGS and USFWS information to 

characterize qualitatively the location and types of national water resources. This 

information is depicted on maps but not for purposes of quantifying the extent of 

waters covered under CWA regulatory programs.

Home Builders Association of Tennessee (Doc. #19581)

8.75 The Proposed Rule establishes a one-size-fits-all designation for all tributaries to covered 

waters. The proposed deconstructed definition of tributary means a water: [P]hysically 

characterized by the presence of a bed and banks and ordinary high water mark, as 

defined at 33 CFR 328.3(e), which contributes flow, either directly or through another 

water, to a water identified in paragraphs (1)(i) through (iv) of this definition. 

 

Amendment to 10 CSR 20-7.031, Missouri Water Quality Standards at 4,25 (Nov. 9,2012) available at

http://www.dor_mo.gov/env/wpp/docs/master-rir-wqs-112312.pdf

(Based on USGS study, "A Gap Analysis for Riverine Ecosystems of Missouri" [2005], Missouri decided to 

designate all perennial rivers and stream, intermittent streams with permanent pools, and those waters spatially 

represented by the 1 : 100,000 scale NHD, but not ephemeral waters.)
Clean Water Rule Response to Comments – Topic 8: Tributaries

72

In addition, wetlands, lakes, and ponds are tributaries (even if they lack a bed and banks 

or ordinary high water mark) if they contribute flow, either directly or through another 

water to a water identified in paragraphs (1)(i) through (iii) of this definition. 

A water that otherwise qualifies as a tributary under this definition does not lose its status 

as a tributary if, for any length, there are one or more man-made breaks (such as bridges, 

culverts, pipes, or dams), or one or more natural breaks (such as wetlands at the head of 

or along the run of a stream, debris piles, boulder fields, or a stream that flows 

underground) so long as a bed and banks and an ordinary high water mark can be 

identified upstream of the break.

A tributary, including wetlands, can be a natural, man-altered, or man-made water 

and includes waters such as rivers, streams, lakes, ponds, impoundments, canals, 

and ditches not excluded in paragraph (2)(iii) or (iv) of this definition. 

The definition of tributary causes substantial concern for the construction industry. For 

example, jurisdictional waters may require lateral buffering, permitting and costly 

compensatory mitigation. When all tributaries are considered jurisdictional, even all 

ephemeral streams, including Tennessee's wet weather conveyances, they become 

federalized and not only create additional jurisdictional waters, but also cause significant 

land use determinations that now are within the sole province of the states. Construction 

projects require regulatory certainty particularly when platting subdivisions and making 

investment decisions. Identifying nearly all conveyances as jurisdictional may increase 

certainty, but hinders actual operations. For example, in Tennessee with the general 

permit for wet weather conveyances, excess material, such as rock and dirt, can be 

disposed of in wet weather conveyances. If, however, these wet weather conveyances are 

waters of the United States, as described in the Proposed Rule, the ability to use such

features could be severely restricted if not entirely eliminated. This creates extra cost to 

the home builder with no appreciable environmental benefit as described in Paragraph III 

of these comments. Likewise, some wet weather conveyances may require construction 

buffers which would limit the footprint of a subdivision, and, in some cases make 

development impractical. Impacts to wet weather conveyances from moving equipment 

across a wet weather conveyance during construction will also become a substantial issue 

and create enforcement concerns. This results in notices of violations, agency orders, or 

even civil or criminal enforcement for what has been a lawful activity. (p. 3-4)

Agency Response: See summary response for section 8.1. Section III(C) of the 

preamble and Section VII of the Technical Support Document discuss the science 

supporting the agencies’ determination that waters meeting the definition of 

“tributary” have a significant nexus because they significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas. Planning and zoning for land use decisions is solely a local 

and/or state authority, and is beyond the scope of this rule.
Clean Water Rule Response to Comments – Topic 8: Tributaries

73

Freeport-McMoRan Inc. (Doc. #14135, #14135.1, and #14135.2)

8.76 The plain text of the Clean Water Act limits EPA and the Corps’ jurisdiction to waters of 

the United States.52 While it is well-established that this means something more than 

simply navigable waters,53 Justice Kennedy’s concurrence in Rapanos requires the 

Agencies to demonstrate that waters “either alone or in combination with similarly 

situated lands in the region, significantly affect the chemical, physical, and biological 

integrity of other covered waters more readily understood to be ‘navigable’” in order to 

establish jurisdiction.54 The Agencies themselves recognize this in their proposed 

definition of “significant nexus,” which requires that the connection be more than 

speculative and insubstantial.55 However, when applied to the arid west, the Proposed 

Rule’s definition of “tributary” and its conclusion that all tributaries are jurisdictional 

does not meet this requirement.

II. Features that would be defined as “tributaries” in the arid west under the 

Proposed Rule may not have the biological connection to traditional navigable 

waters that the Draft Connectivity Report and Proposed Rule assert.

With respect to biological connectivity, the Proposed Rule concludes that “[t]ributaries, 

including intermittent and ephemeral streams, are critical in the life cycles of many 

organisms capable of moving throughout river networks.”56 The Proposed Rule further 

finds that tributaries “have important effects on the biological integrity of . . . [traditional 

navigable] waters, contributing materials to downstream food networks and supporting 

populations for aquatic species, . . . .”57 With respect to ephemeral streams specifically, 

the Proposed Rule notes that they can play an important role in sediment storage that 

improves downstream water quality.58 While all of these observations may be correct in 

humid systems and perennial streams that receive regular flows, they do not hold when 

applied to the channels of the arid west, in which the impact of ephemeral tributaries in 

particular is frequently insignificant and insubstantial, much less critical.

Most biological communities require the sustained presence of water in channels to 

form.59 As a result, they are unlikely to exist in arid west channel systems where flow is 

 

52 See 33 U.S.C. § 1362(7) (defining “navigable waters” to be “waters of the United States, including the territorial 

seas.”).

53 United States v. Riverside Bayview Homes, 474 U.S. 121, 133 (1985).

54 547 U.S. 715, 780 (2006) (emphasis added). In rejecting the Corps’s existing standard for tributaries at the time of 

Rapanos, Justice Kennedy noted that the standard “seems to leave wide room for regulation of drains, ditches, and 

streams remote from any navigable-in-fact water and carrying only minor water volumes towards it.” Id. at 781. 

Justice Kennedy stated that this flawed standard “precludes its adoption as the determinative measure of whether 

adjacent wetlands are likely to play an important role in the integrity of an aquatic system comprising navigable 

waters as traditionally understood.” Id. (emphasis added). The existing standard for tributaries rejected in Rapanos

(i.e., “the Corps deems a water a tributary if it feeds into a traditional navigable water (or a tributary thereof) and 

possesses an ordinary high-water mark” (id.)) is the same flawed standard that the Agencies are attempting to 

support in the Proposed Rule.

55 79 Fed. Reg. at 22,220.

56 79 Fed. Reg. at 22,205.

57 Id.

58 Id. at 22,231.

59 Technical Comments at 3.
Clean Water Rule Response to Comments – Topic 8: Tributaries

74

an abnormal condition.60 The Draft Connectivity Report notes that isolated pools in 

dryland rivers are key refuges for fish and aquatic insects to survive in ephemeral waters 

during periods when there is no flow.61 However, the Draft Connectivity Report provides 

no evidence of biological connectivity or support of fish or aquatic insect populations in 

cases where the predominant condition of the water is not only no flow but also a 

completely dry channel bed for most of the year. In cases such as the Santa Cruz River

where both the mainstem and channels flowing into it are nearly always dry, the 

biological connections posited by the Draft Connectivity Report and the Proposed Rule 

simply do not exist.

III. Features that would be defined as “tributaries” in the arid west under the 

Proposed Rule do not always have the chemical connection to traditional navigable 

waters that the Draft Connectivity Report and Proposed Rule assert.

The Proposed Rule concludes that tributaries “influence the chemical composition of 

downstream waters, through the transport and removal of chemical elements and 

compounds, such as nutrients, ions, dissolved and particulate organic matter, pollutants, 

and contaminants.”62 However, the Proposed Rule notes that “chemical effects are 

closely related to hydrological connectivity.”63 The Proposed Rule further suggests that 

ephemeral streams can play an important role in nutrient cycling.64 Based on the San 

Pedro River “case study” the Proposed Rule concludes that “[e]xtensive downstream 

river riparian communities are supported by water, sediment, and nutrients exported to 

the river from ephemeral tributaries . . . .”65

However, these conclusions are not relevant to arid west channel systems that lack 

sustained flows. In most arid west systems, water flows are “flashy,” meaning that water 

moves quickly across the landscape in response to a rain event and quickly dissipates. In 

contrast, many of the chemical processes described in the Proposed Rule only occur when 

waters have a long residence time in channels.66 Because of the flashy nature of flows in 

arid west channels, the potential for chemical transformations is minimal.67

...

V. Even when “tributaries” in the arid west have a physical connection with 

traditional navigable waters, it is not possible to conclude this is more than a mere 

hydrologic connection without site-specific data.

The Proposed Rule claims that its legal basis is Justice Kennedy’s concurrence in 

Rapanos and concedes that under this test “a mere hydrologic connection may not suffice 

in all cases to establish CWA jurisdiction and there needs to be ‘some measure of the 

 

60 Id. at 4.

61 Draft Connectivity Report at 4-68.

62 79 Fed. Reg. at 22,205.

63 Id.

64 Id. at 22,231.

65 Id. at 22,232.

66 Technical Comments at 3.

67 Id.
Clean Water Rule Response to Comments – Topic 8: Tributaries

75

significance of the connection for downstream water quality.’”68 According to the 

Proposed Rule, there are two measures by which tributaries meet this criterion based on a 

physical connection to traditional navigable waters. First, the Proposed Rule concludes 

that even seasonally dry tributaries are the dominant source of flow for the rivers they 

feed and that “[t]he physical effects of tributaries are particularly clear after intense 

rainfall occurs over only the upper tributary reaches of a river network.”69 As explained 

in the attached Technical Comments, in the “losing streams” common in the arid west, 

rainfall events over the upper reaches of a network will often fail to reach downstream 

traditional navigable waters.70 In these cases, without site-specific data confirming the 

continuity of flows, EPA and the Corps cannot interpret a continuous network of features 

that appear to be dry channels as more than a “mere hydrologic connection” that 

evidences water at one time flowed there. This does not meet the standard of Rapanos

and therefore cannot be used as a basis for the broad assertion of jurisdiction resulting 

from the Proposed Rule’s definition of “tributary.”

Second, the Proposed Rule finds that “[t]ributaries, particularly headwaters, shape and 

maintain river channels by accumulating and gradually or episodically releasing sediment 

and large woody debris into river channels.”71 The proposal also concludes that evidence 

of sediment transport is seen in ephemeral streams.72 However, as explained in the 

attached Technical Comments, the losing nature of arid west streams means that there is 

no hydrologic connection (and therefore no sediment transport) for most rainfall events.73

Further, because of the likely disconnection between headwaters and traditional 

navigable waters in losing streams, neither sediment nor water will be conveyed to them 

through arid west channels at any regular intervals.74

The Proposed Rule fails to demonstrate that the occasional connection between arid west 

channels and traditional navigable waters in losing streams rises above the level of a 

“mere hydrologic connection.” To do so, the Agencies would need to establish threshold 

criteria for flow—in terms of both volume and duration—that are required for the 

connectivity the Agencies assume to be present.75 Further these criteria should be crafted 

in a way that recognizes continuous flows from headwater “tributaries” to traditional 

navigable waters will depend on the specific geologic characteristics of the watershed. 

Therefore, without site-specific data to demonstrate that these losing streams have a 

physical connection that has relevance to downstream flows or water quality, the 

Agencies do not have the authority to adopt the broad proposed definition of “tributary” 

and apply it to arid west systems. (Doc. #14135, p. 3-5, 6-7)

8.77 Because of the lack of review of arid landscape headwaters in the Agencies' analysis of 

connectivity, below we begin with a brief review of the relevant processes and features in 

 

68 40 79 Fed. Reg. at 22,195 (quoting 547 U.S. at 784-85).

69 Id. at 22,227.

70 Technical Comments at 12.

71 79 Fed Reg. at 22,227.

72 Id.

73 Technical Comments at 13.

74 Id.

75 Id. at 14.
Clean Water Rule Response to Comments – Topic 8: Tributaries

76

arid landscapes and how they operate at the most distal extent of the channel network in 

arid landscapes.

2. Relevant Processes in Arid Tributaries

The objective of the Clean Water Act is to sustain and restore the physical, chemical, and 

biological integrity of the nation’s waters. This objective provides a rubric with which to 

consider what types of processes are important when evaluating the potential upstream 

reach of jurisdiction that is legally supportable under the CWA. Here we briefly review 

processes relevant to headwater arid systems.

Chemical transformations of materials (e.g., nitrogen, carbon, phosphorus) occur in 

tributaries, and thus downstream waters can be affected by the characteristics of the 

tributaries. For instance, the width and depth, along with sediment size of the tributary, 

can affect the chemical transformations that occur. These types of transformations are 

one of the primary factors for the agencies expanding their jurisdiction beyond navigable 

waters and upstream into tributaries. However, it is increasingly recognized that these 

chemical transformations are quite dependent on the flows in the channel; during high 

flows, there is limited, and possibly no opportunity for transformations to occur.76 During 

lower flows when flowing water is in contact with channel boundaries for longer periods 

of time, the channel itself can be a location of transformations, and thus make the 

tributary important in and of itself and not just as a conveyor of chemicals. In systems in 

which most materials and water are moved during infrequent, rare storm events, the role 

of “flashy” tributaries in chemical transformations will be minimal or negligible.77

Similarly, biological processes and communities can occur in tributaries. Clearly, many 

of these communities and processes are unique to tributaries, and thus often the impetus 

for the protection of channels—to protect the channel-dwelling organisms and associated 

ecosystems. Similar to chemical processes, the duration of water flowing within channels 

is a clear necessity for many, if not most, of the biological characteristics to form and be 

sustained. While some biological processes and communities can recover and occur 

quickly and for short periods of time, many biological processes and communities require 

sustained presence of some water, and often sustained quantities of flowing water; 

discharge is often considered the “master variable” for stream ecosystems.78 While 

certainly droughts—the lack of flow in stream ecosystems—are important ecological 

events, the research that has emphasized the importance of droughts has emphasized its 

importance as a disturbance event, i.e., its importance when it is unusual in comparison to 

the usual characteristics of baseflow.6 In arid streams, no-flow can be the normal 

condition and flow the abnormal condition.

As an example, the Santa Cruz River in Arizona (at the Continental USGS gage) has a 

drainage area of 1,682 square miles yet has a median annual flow of 0 cfs and typically 

has no flow in the river for 326 days per year (see case study below). Flow in the river 

 

76 Doyle, M.W., 2005. Incorporating hydrologic variability into nutrient spiraling. Journal of Geophysical Research 

– Biogeosciences 110, G1, doi:10.1029/2005JG000015.

77 Ibid, Doyle, 2005.

78 Poff, N.L., J.D. Allan, M.B. Bain, J.R. Karr, K.L. Prestegaard, B.D. Richter, R.E. Sparks, and J.C. Stromberg, 

1997. The natural flow regime. BioScience 47, 769-784.
Clean Water Rule Response to Comments – Topic 8: Tributaries

77

occurs only in response to unusually heavy rain events, with flows lasting only a few 

days at a time. That is, the normal condition for this large arid river is no flow. Most 

tributaries of the Santa Cruz River will have even rarer flows as headwater systems are 

more “flashy” than their downstream main channels, thus making biological processes 

nonexistent and expectations of chemical transformations unrealistic in either the main 

channel or, in particular, the headwater tributaries. Federal regulatory agency researchers 

have relied heavily on the San Pedro River as their prototype arid system. Importantly, 

the San Pedro River behaves quite differently from most arid rivers like the Santa Cruz 

(discussed in more detail in case study below). This marked contrast between these two 

adjacent systems emphasizes the fact that arid systems are distinct from humid systems, 

and are often distinct from each other. These distinctions translate to large differences in 

expectations of chemical or biological processes that might occur. In many arid systems, 

the sustained lack of flow makes the expectation of chemical transformations or 

sustaining of biological processes unrealistic.

In sum, some type of sustained water presence and flow must be present for chemical or 

biological processes or communities to exist in a channel. Absent sustained flow, a 

channel will function solely as a physical conveyance of water, sediment, and materials. 

Absent sustained flow, a tributary will have minimal, if any role in transforming 

materials through biogeochemical processes. Absent sustained flow, a channel’s primary 

role in the surface water system will be in its physical conveyance of water, sediment, 

and materials. Absent sustained flow, the regulatory justification for asserting 

jurisdiction on a channel must be its influence on downstream waters through its physical 

conveyance of water, sediment, and materials.

Based on this rationale, it is clear that the physical processes which occur in arid stream 

systems are essential to understand, along with the potential for identifying the 

longitudinal extent of characteristic “fluvial” processes. (Doc. #14135.1, p. 3-4)

Agency Response: See summary responses for sections 8.1, 8.1.1 and 8.1.2. See 

also TSD Section VII, including Section VII.B.vi, and the Compendium 9 summary 

response for specific discussion of how intermittent, ephemeral and headwaters 

tributaries significantly affect the physical chemical and biological integrity of (a)(1) 

through (a)(3) waters.

8.78 While EPA and the Corps have, in some cases, historically asserted CWA jurisdiction 

over these types of features, assertion of such jurisdiction has been controversial. It has 

also been limited by the requirement that these features are only jurisdictional if they 

have a "significant nexus" to a traditionally-navigable water. The Draft Proposed Rule 

does away with this important limitation on CWA jurisdiction, expanding CWA 

jurisdiction to features that are effectively dry land so long as they ever---or might ever---

contribute the slightest increment of water flow to downstream traditional navigable 

waters, no matter how small that flow or how far away a navigable water might be. While 

this is flatly inconsistent with Rapanos,

79 this submission focuses on the scientific and 

land-use issues, not the legal ones. Moreover, the Draft Proposed Rule's exemption of 

"gullies" and "rills" does not suffice to address this concern, because the rule provides no 

 

79 547 U.S. 784-5 ("mere hydrologic connection should not suffice in all cases") (Kennedy, J.).
Clean Water Rule Response to Comments – Topic 8: Tributaries

78

well-defined basis to distinguish when something is a gully or rill in contrast to an 

ephemeral ''tributary" - all of which may have an "ordinary high water mark" as that term 

is used in the Draft Proposed Rule. In fact, it has not been our experience that any 

drainage or dry wash has ever been deemed exempt as a gully or rill. (Doc. #14135.2, p. 

2)

Agency Response: See summary response for section 8.1. Section III(C) of the 

preamble and Section VII of the Technical Support Document discuss the science 

supporting the agencies’ determination that waters meeting the definition of 

“tributary” have a significant nexus because they significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas. Similarly, section IV(G) of the preamble and section VIII 

of the Technical Support Document discuss “adjacent waters.” Section I of the 

Technical Support Document describes the legal basis of the final rule, including its 

consistency with the statute and case law.

National Stone, Sand and Gravel Association (Doc. #14412)

8.79 The "jurisdiction by rule" means that any water meeting the new definition of "tributary" 

has a significant nexus to a TNW based on the evidence of some flow based on an 

observed “Ordinary High Water Mark" (OHWM) or presence of a "bed and banks" (even 

for water features that are dry most of year.) This proposed rule will categorically sweep 

in any waters meeting this definition, including all adjacent waters, and stretches Justice 

Kennedy's significant nexus test beyond any logical reading. (p. 7)

...the Association respectfully requests that EPA and the Corps withdraw the proposed 

rule, and any new rule must incorporate the following recommendations:

 Eliminating "jurisdiction by rule" for any water that meets the tributary 

definition including adjacent waters and wetlands. Defining "tributary" to 

require clear evidence of (1) an OHWM and (2) clear evidence that the water 

and its adjacent wetlands provide identifiable water quality benefits to the 

closest TNW due to demonstrated overland flow. Clarify that a water loses its 

tributary status if, for any length, there are one or more man-made breaks 

(such as bridges, culverts, pipes, dams or roads) unless site specific evidence 

demonstrates that, under normal circumstances, it is likely that water will flow 

on the other side of the break. This clarification should also state that the 

presence of a continuous OHWM on the opposite side of the break is not 

determinative of a significant nexus to the closest TNW. 

... (p. 7, 55)

Agency Response: See summary response for section 8.1. Section III(C) of the 

preamble and Section VII of the Technical Support Document discuss the science 

supporting the agencies’ determination that waters meeting the definition of 

“tributary” have a significant nexus because they significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas. Similarly, section IV(G) of the preamble and section VIII 

of the Technical Support Document discuss “adjacent waters.” Section I of the 
Clean Water Rule Response to Comments – Topic 8: Tributaries

79

Technical Support Document describes the legal basis of the final rule, including its 

consistency with the statute and case law.

Wyoming Mining Association (Doc. #14460)

8.80 ...The Science Advisory Board (SAB) stated in their review of the Connectivity Report 

that it is not appropriate to treat connectivity as a binary property (connected versus not 

connected). Further the SAB recommended "that the interpretation of connectivity be 

revised to reflect a gradient approach that recognizes variation in the frequency, duration, 

magnitude, predictability and consequences of connections."4 As pointed out in the GEI 

report provided in the WAC comments, "all tributaries ... exist on a gradient of 

connectivity, and the science has not identified the point on the gradient (i.e., the strength 

of connectivity) where the significant nexus falls." Additionally this connectivity report, 

on which the EPA is relying to support their proposed definition of "tributary", has failed 

to go through the process of peer review for finalization prior to the close of the comment 

period on the proposed rule.

Ephemeral streams are common in the state of Wyoming and many surface mines 

traverse numerous ephemeral drainages throughout the life of a mine. Under the tributary 

definition, ephemeral drainages are per se jurisdictional80. This is a huge shift from the 

current regulations as ephemeral drainages have historically been outside CWA 

jurisdiction81 because they flow only infrequently and the flows are rarely in quantities 

that could affect other more permanent or significant water bodies. Neither the 

Connectivity Report nor Appendix A of the preamble demonstrate that all ephemeral 

features have significant chemical, physical and biological effects to TNW and therefore 

ephemeral drainages should not be considered jurisdictional in an all-inclusive manner. 

Note that according to the proposed rule "Approximately 59% of streams across the 

United States (excluding Alaska) flow intermittently or ephemerally...".82 This proposed 

rule has the potential to drastically increase the number of streams currently considered 

jurisdictional if all ephemeral drainages become automatically jurisdictional. (p. 4)

Agency Response: See summary responses for sections 8.1, 8.1.1 and 8.1.2. 

Section III(C) of the preamble and Section VII of the Technical Support Document 

discuss the science supporting the agencies’ determination that waters meeting the 

definition of “tributary” have a significant nexus because they significantly affect 

the chemical, physical, and biological integrity of traditional navigable waters, 

interstate waters, and the territorial seas. See also Section 9 “Scientific Evidence 

Supporting the Rule” of the Response to Comments.

8.81 Indefinite Definition of Tributaries

 

80 79 Fed. Reg. at 22,218-19.

81 See Missouri Department of Natural Resource, Regulatory Impact Report In Preparation for Proposing An 

Amendment to 10 CSR 20-7.031, Missouri Water Quality Standards at 4, 25 (Nov. 9,2013), available at

http://www.dnr.mo.gov/env/wpp/docx/master-rir-wqs-112312.pdf (Based on USGS study, "A Gap Analysis for 

Riverine Ecosystems of Missouri" (2005), Missouri decided to designate all perennial rivers and streams, 

intermittent streams with permanent pools, and those waters spatially represented by the 1:100,000 scale NHD, but 

no ephemeral waters.)

82 79 Fed. Reg. at 22,231.
Clean Water Rule Response to Comments – Topic 8: Tributaries

80

The proposed rule catalogs tributaries in an all-inclusive manner which will lead to overreaching jurisdiction. According to the proposed definition, tributaries can be natural, 

man-altered, or manmade waters and includes waters such as rivers, streams, lakes, 

ponds, impoundments, canals, and ditches. Open ended statements regarding such matters 

as "indefinite lengths of disruptions" to tributary features (bed, bank, or Ordinary High 

Water Mark [OHWM]) and waters contributing flow directly or indirectly to 

jurisdictional waters in any way create concern as the ambiguity of the tributary 

definition effectively classifies nearly all bodies of water, even those remote from 

navigable-in- fact water and those that carry minor volumes of water ephemerally, as 

categorically jurisdictional.

The rule proposes that any water considered as a tributary even if there is a man-made 

(e.g., bridge, culvert, pipe or dam) or natural break (e.g., debris piles, boulder fields) for 

any length as long as the bed, bank and OHWM can be identified upstream of the break 

will remain jurisdictional. This is a common occurrence in arid regions and is an 

unreasonable requirement. Assuming a significant nexus based on such tenuous 

connections is not supported by any science (cite SAB report on connectivity as a 

gradient and GEI report). It greatly expands the scope of waters that would be considered 

tributaries and therefore jurisdictional. (p. 5)

Agency Response: See summary response for section 8.1. See summary response 

for section 8.3, “Ordinary High Water Mark (OHWM).” Section III(C) of the 

preamble and Section VII of the Technical Support Document discuss the science 

supporting the agencies’ determination that waters meeting the definition of 

“tributary” have a significant nexus because they significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas. See also Section 9 “Scientific Evidence Supporting the Rule” 

of the Response to Comments. Section I of the Technical Support Document 

describes the legal basis of the final rule, including its consistency with the statute 

and case law.

The Mosaic Company (Doc. #14640)

8.82 The determination of significant nexus for all waters defined as tributaries in the 

proposed rule is based on the draft EPA Connectivity Report as well as additional 

information presented in Appendix B of the preamble. The proposed rule states that all 

tributaries, including small, intermittent, and ephemeral systems either alone or in 

combination with other tributaries in a watershed have a significant nexus to downstream 

traditional navigable waters. Mosaic agrees that tributaries have the potential to provide 

important functions as sources and sinks of materials and pollutants, and as a source of 

flow to downstream waters. But Mosaic disagrees that the scientific evidence allows for a 

categorical determination that all tributaries, regardless of flow magnitude or duration, or 

position in the watershed meet the significant nexus standard. Additionally, Mosaic 

disagrees that aggregating the potential effects of multiple small waterbodies in a 

watershed is a defensible approach to determining significant nexus. 

...An alternative approach for determining what tributaries categorically have a 

significant nexus and are, therefore, jurisdictional is to refine the existing 2008 Guidance 

on jurisdiction and the Supreme Court's plurality opinion concerning relatively 
Clean Water Rule Response to Comments – Topic 8: Tributaries

81

permanent waters (RPW) . Ignoring the plurality opinion, the proposed definition of 

tributary eliminates any discussion of RPWs and resorts to the more tenuous aggregation 

of certain connections to establish significant nexus. The agencies should define RPW in 

terms of metrics such as flow rate, volume and duration of hydrologic connection, and 

distance from traditional navigable water in conjunction with ecological metrics to 

establish a threshold above which a tributary not only has a connection, but meets a 

threshold of "significance" necessary to establish jurisdiction. This RPW threshold would 

define when an individual conveyance meets the definition of tributary and is 

categorically jurisdictional by rule. Conveyances not meeting the RPW threshold as a 

tributary for jurisdictional purposes would not automatically be considered nonjurisdictional, but would be subject to an individual determination based on the site 

specific potential to affect the nearest downstream traditional navigable water.

The above approach is more scientifically defensible given the draft EPA Connectivity 

Report conclusion that individual effects from small intermittent and ephemeral 

conveyances may be "small", but aggregation "might" make the effects substantial. The 

recommended approach allows for site specific identification of potential aggregation 

effects that "might" be substantial for a given watershed or region , but does not 

categorically assume that potential effects of small, intermittent, and ephemeral 

conveyances will be substantial. The conclusion that downstream effects "might" be 

substantial when aggregated is not justification for the determination that all small, 

intermittent, or ephemeral conveyances have a significant nexus to downstream waters 

and directly contravenes both the plurality's and Kennedy's Rapanos opinions. (p. 20, 21)

Agency Response: Section III(C) of the preamble and Section VII of the Technical 

Support Document discuss the science supporting the agencies’ determination that 

waters meeting the definition of “tributary” have a significant nexus because they 

significantly affect the chemical, physical, and biological integrity of traditional 

navigable waters, interstate waters, and the territorial seas. Section II of the 

Technical Support Document describes the agencies’ significant nexus analysis, and 

Section I describes the legal basis of the final rule, including its consistency with the 

statute and case law.

Continental Resources, Inc. (Doc. #14655)

8.83 A number of additional aspects of the proposed definition of "tributary" are also 

troublesome. First, there is no requirement that a tributary (or ditch) have a bed, bank, or 

ordinary high water mark ("OHWM"). The definition includes the entire length of the 

tributary including areas upstream of a natural or man-made break (e.g., bridges, culverts, 

pipes, dams, debris, or underground flow). Second, the definition of tributary no longer 

requires a certain volume of flow, frequency of flow, or notion of proximity to a 

traditional navigable water. Third, all tributaries are per se jurisdictional if they contribute 

directly or indirectly to flow. See generally 79 Fed. Reg. at 22,262 (Proposed 33 C.F.R. § 

328.3(a)(5)). The agencies' legal and scientific justifications for this expanded definition 

of tributaries are utterly insufficient. There is every reason to believe the majority of the 

justices in Rapanos would have struck down this definition of "tributary" in the Proposed 

Rule based on its lack of any statutory or judicial support and the agencies' not-so-subtle 

effort to expand markedly the limited extent of their jurisdictional reach. (p. 7)
Clean Water Rule Response to Comments – Topic 8: Tributaries

82

Agency Response: See summary response for section 8.1. See summary response 

for section 8.3, “Ordinary High Water Mark (OHWM).” Section III(C) of the 

preamble and Section VII of the Technical Support Document discuss the science 

supporting the agencies’ determination that waters meeting the definition of 

“tributary” have a significant nexus because they significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas. Section I of the Technical Support Document describes the 

legal basis of the final rule, including its consistency with the statute and case law.

Sinclair Oil Corporation (Doc. #15142)

8.84 While it is possible that categorical determinations could be condoned if the proposed 

rule defined the categories of water which are per se jurisdictional with a degree of 

specificity sufficient to ensure that jurisdiction did not extend beyond the limits 

established by SWANCC, and only applied to waters that did, in fact, have a significant 

nexus to traditional navigable waters, the proposed rule does not do that. Instead, the 

proposed rule establishes per se jurisdiction over "tributaries" and "adjacent" waters and 

defines both in such ambiguous terms that there is no perceptible limit to the reach of 

those definitions. In addition to making it practically impossible to know whether a 

particular water is going to be considered per se jurisdictional, the ambiguity in the 

definitions destroys any legal basis for making categorical jurisdictional determination.

For example, the proposed rule asserts that all tributaries are per se jurisdictional, 

because tributaries have a "significant nexus to a traditional navigable water, interstate 

water, territorial sea." 79 Fed. Reg. 22,201. However, the Agencies define "tributaries" to 

include any water that contributes any flow to a downstream jurisdictional water. Id. at 

22,263. Such a definition is a clear contradiction of Justice Kennedy's warning that a 

significant nexus cannot be presumed for a water with a hydrologic connection because 

"a mere hydrologic connection should not suffice in all cases; the connection may be too 

insubstantial for the hydrologic linkage to establish the required nexus with navigable 

waters as traditionally understood." Rapanos, 547 U.S. at 784. (p. 7-8)

Agency Response: Section III(C) of the preamble and Section VII of the Technical 

Support Document discuss the science supporting the agencies’ determination that 

waters meeting the definition of “tributary” have a significant nexus because they 

significantly affect the chemical, physical, and biological integrity of traditional 

navigable waters, interstate waters, and the territorial seas. Similarly, section 

IV(G) of the preamble and section VIII of the Technical Support Document discuss 

“adjacent waters.” Section I of the Technical Support Document describes the legal 

basis of the final rule, including its consistency with the statute and case law.

8.85 If the Agencies move forward with a version of the proposed rule, the Agencies must

modify several aspects of the proposed rule. To withstand review and provide the clarity,

certainty and efficiency the Agencies claim is the reason for the proposed rule, the rule 

must at a minimum:

...
Clean Water Rule Response to Comments – Topic 8: Tributaries

83

 Limit the definition of "tributary'' to those channelized features exhibiting a 

bed and bank and ordinary high water mark that is consistently identifiable all 

the way to the downstream "water of the United States" into which it flows.

 Amend the definition of "tributary'' to set a minimum contribution of flow to 

the traditional navigable water, interstate water, or territorial sea that is 

necessary to establish the channelized feature as a "water of the United 

States." 

... (p. 19)

Agency Response: See summary response for section 8.1. See summary response 

for section 8.3, “Ordinary High Water Mark (OHWM).”

Halliburton Energy Services, Inc. (Doc. #15509)

8.86 In effect, federal jurisdiction would extend to all tributaries, no matter how remote or 

ephemeral and without regard to the significance of a specific tributary's relationship to a 

traditional navigable water - i.e., without regard to the nature of the flow in the stream, 

the evaporative losses within the stream and distance to a navigable-in-fact water (which 

might preclude a contaminant from ever reaching that water), or the relative effect of the 

tributary on navigable waters compared to the impact of more directly adjacent but 

unregulated areas. Indeed, the proposed definition goes further, extending beyond what 

would commonly be viewed as a "tributary" by ignoring breaks in the OHWM to capture 

additional upstream stretches with even further attenuated connections to traditional 

navigable waters. Thus, no matter how implausible the likelihood of conveyance of 

pollutants to navigable waters, the "tributary" would be per se jurisdictional.

The Agencies justify this result by aggregating the impacts of all streams in a watershed 

on the physical, chemical and biological integrity of traditionally navigable waters, 

concluding that the aggregated effects are significant without any analysis of specific 

facts relevant to particular watersheds or streams within them. Thus, while Justice 

Kennedy suggested that the Agencies could identify categories of tributaries that are 

"significant enough that wetlands adjacent to them are likely . . . to perform important 

functions for an aquatic system incorporating navigable waters,"83 the Agencies have 

instead adopted the simple expedient of claiming that all tributaries fit neatly into a single 

category. (p. 3-4)

Agency Response: See summary response for section 8.1. Section I of the 

Technical Support Document describes the legal basis of the final rule, including its 

consistency with the statute and case law. Section III(C) of the preamble and 

Section VII of the Technical Support Document discuss the science supporting the 

agencies’ determination that waters meeting the definition of “tributary” have a 

significant nexus because they significantly affect the chemical, physical, and 

biological integrity of traditional navigable waters, interstate waters, and the 

territorial seas. See also summary response for section 8.3, “Ordinary High Water 

Mark (OHWM).”

 

83 Rapanos v. United States, 547 U.S. 715, 781 (2006) (Kennedy, J., concurring).
Clean Water Rule Response to Comments – Topic 8: Tributaries

84

Illinois Coal Association (Doc. #15517)

8.87 Yet the Proposed Rule, with its revised definition of "tributary," seeks to do just that, 

sweeping all tributaries, including most ditches, into the definition of waters of the U.S., 

without regard to flow, duration of flow, proximity to or effect upon traditional navigable 

waters. See Proposed Rule at 22263. To compound this error, the Agencies jettison even 

the barest and minimal requirements of OHWM and bed and bank, well-established 

features of the historical definition of tributaries under the CWA, by proposing to expand 

the definition of tributaries to water features, such as wetlands, that lack bed and bank 

and OWHM. See Proposed Rule at22202. ("T]he water must also have a bed and banks 

and ordinary high water mark (except where a wetlands is a tributary) . . .").

8.88 The new definition of "tributary" in the Proposed Rule would also radically alter this 

term's traditional meaning and long-held practice by extending the term to lakes, ponds 

and wetlands, even where they lack traditional indicia of tributary - i.e., OHWM and bed 

and bank. Provided the tributary "contribute[s] flow, either directly or through" (a)(l) to 

(a)(4) waters, no matter how significant or insignificant the flow is, under this Proposed 

Rule it will be deemed jurisdictional. Proposed Rule at 22272.

The Agencies' proposed approach deeming all tributaries as per se jurisdictional is 

inconsistent with the Agencies' desire for consistency, clarity and certainty to the extent 

the new definition of "tributary" includes wetlands and other water bodies that do not 

contain clear and discernible features such as bed and bank: and OHWM. The definition 

is also at odds with the Agencies' description of a tributary elsewhere in the Proposal, 

where the agencies seem to acknowledge the necessary presence of bed and bank: and 

OHWM. ("A tributary is a longitudinal surface feature that results from directional 

surface water movement and sediment dynamics demonstrated by the presence of bed 

and banks, bottom and lateral boundaries, or other indicators of OHWM "). Id. at 22202 

(emphasis added). 

In addition to the questionable legality of the Agencies' significant departure from 

established terminology and meaning, we are deeply concerned about the practical 

hardships that the new definition of "tributary" would impose on the regulated 

community. The revised definition is hardly the picture of clarity that has been promised. 

Even after this revision, the question will remain - where does a tributary begin? As the 

Proposed Rule notes, although the upper limit of a tributary is usually established "where 

the channel begins" (see id.), under this new definition, which now includes waters 

without an OWHW or bed and bank, a tributary could begin well into the headwaters far 

above any defined channel and remote from traditional navigable waters, provided that it 

merely "contributes flow, either directly or through another water. ... " Id. at 22272. 

The use of OHWM as the primary physical indicator in determining the lateral limits of 

jurisdiction has been the Corps' practice for many years.84 To abandon its use and 

redefine a jurisdictional tributary as any feature that "drains" to a traditional navigable 

 

84 See Corps RGL 05-05, Ordinary High Water Mark Identification, located at 

http://www.usace.anny.miVPortals/2/docs/civilworks/regulatory/cwa guide/app 11 rg105-05.pdf; See also GAO04297 Report, Waters and Wetlands, Corps of Engineers Needs to Evaluate Its District Office Practices in 

Determining Jurisdiction, located at http://www.gao.gov/assets/250/24l520.pdf
Clean Water Rule Response to Comments – Topic 8: Tributaries

85

water, regardless of the volume of flow or presence of an OHWM, creates even greater 

confusion and uncertainty regarding the lateral limits of a tributary. (p. 9-10)

Agency Response: See summary response for section 8.1. See summary response 

for section 8.3, “Ordinary High Water Mark (OHWM).” Paragraph (b) of the final 

rule excludes many features, including most ditches that are not relocated 

tributaries or excavated in tributaries. See summary responses in Compendium 7 of 

this RTC, “Features and Waters Not Jurisdictional,” for a broad discussion of the 

final rule’s exclusions and Compendium 6, Section 6.2 of this RTC, “Excluded 

Ditches,” for a more focused discussion on the revisions and clarifications of the 

ditch exclusions.

Dominion Resources Services, Inc. (Doc. #16338)

8.89 The proposed rule categorically establishes that tributaries have a significant nexus to 

traditional navigable waters, interstate waters, and the territorial seas. In a separate 

definition, the proposed rule categorically establishes waters and wetlands “adjacent” to a 

“tributary” as jurisdictional. Any channelized feature, including ditches and other manmade conveyances, no matter how remote from navigable waters, will be jurisdictional 

tributaries if they exhibit a bed, bank and ordinary high water mark. The proposed rule’s 

“tributary” definition would significantly expand the scope of features that are currently 

regulated as tributaries, extending jurisdiction to features like ephemeral drainages and 

stormwater conveyances that have not been and should not be jurisdictional.

...many of our new construction projects and existing operations, both on the electric and 

the natural gas side of the business, conduct activities that are likely to impact ephemeral 

drainages and ditches that could now be considered jurisdictional as a “tributary”. We 

request the agencies meet with stakeholders and federal and state regulatory agencies to 

fully understand the implications of the definition of “tributary” on the regulated 

community and on other federal and state regulatory programs and revise the rule to 

avoid duplication and conflicting requirements... 

...To the extent the agencies move forward with the proposal, we make the following 

recommendations:

 The inclusion of all features that have a bed and bank and contribute flow to 

another WOTUS extends jurisdiction to ephemeral conveyances that have not 

been and should not be jurisdictional. We request that ephemeral features be 

included as features that are not WOTUS as identified in 33 CFR 328.3(b) and 

associated regulatory references. This would be consistent with the rules handling 

of similar features such as “gullies and rills” which are categorically excluded.

... (p. 7)

Agency Response: The commenter is incorrect that “any channelized feature, 

including ditches and other man-made conveyances, no matter how remote from 

navigable waters, will be jurisdictional tributaries if they exhibit a bed, bank and 

ordinary high water mark.” See summary response for section 8.1. Paragraph (b) 

of the final rule excludes many features, including most ditches that are not 
Clean Water Rule Response to Comments – Topic 8: Tributaries

86

relocated tributaries or excavated in tributaries, erosional features that do not meet 

the definition of tributary and stormwater control features created in dry land.

Montana Wool Growers Association (Doc. #5843.1)

8.90 The Preamble states Section (a)(5) provides a categorical rule that requires "no additional 

analysis." 79 Fed. Reg. at 22189. In the same paragraph, the Preamble says determining 

whether a water is a Section (a)(5) tributary requires an inquiry into the "data, science, 

the CWA, and caselaw." 79 Fed. Reg. at 22189. If one statement is true, the other cannot 

be. (p. 7)

Agency Response: The agencies categorical finding of jurisdiction for tributaries 

and adjacent waters was based on a determination that the nexus, alone or in 

combination with similarly situated waters in the region, is significant based on 

data, science, the CWA and caselaw. Because the agencies have determined that 

such waters are jurisdictional by rule, no additional analysis of such waters is 

required. See Section III(C) of the Preamble and Section VII of the Technical 

Support Document.

Alameda County Cattlewomen (Doc. #8674)

8.91 The Proposed Rule Is Beyond the Scope of Authority Provided to the Agencies Under the 

Clean Water Act and Therefore Is Arbitrary, Capricious, an Abuse of Discretion, or 

Otherwise Not in Accordance with the Law

... Never before have the agencies claimed per se jurisdiction over features simply 

because they have a bed, bank and ordinary high water mark and might flow once per 

100 years into a jurisdictional water... And never before have the agencies claimed and it 

been upheld by the Supreme Court that an isolated pond or wetland could become a 

"water of the U.S." based on some tenuous connection to downstream waters. Even the 

Congressional Research Service (CRS) stated that the proposed rule has a "broadly 

defined" new definition of tributary, validating our concern that the proposed rule is a 

significant expansion compared to current regulations.85 (p. 5-6)

Agency Response: Section I of the Technical Support Document describes the 

legal basis of the final rule, including its consistency with the statute and case law. 

Section III(C) of the preamble and Section VII of the Technical Support Document 

discuss the science supporting the agencies’ determination that waters meeting the 

definition of “tributary” have a significant nexus because they significantly affect 

the chemical, physical, and biological integrity of traditional navigable waters, 

interstate waters, and the territorial seas. Also see summary response for section 

8.1.

 

85 Congressional Research Service, EPA and the Army Corps' Proposed Rule to Define "Waters of the United

States", available at 

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&sqi=2&ved=0CB4QFj

AA&url=http%3A%2F%2Ffas.org%2Fsgp%2Fcrs%2Fmisc%2FR43455.pdf&ei=JRYGVJJIzqjIBPjvgcgK&usg=A

FQjCNGq5dlTONe-KCN-v-5FOmTuh38v2w&sig2=UBrr5c69WZitk_UwSF9Odg&bvm=bv.74115972,d.aWw, 

(accessed on Sept. 2, 2014) ("the term "tributary" is newly and broadly defined in the proposal").
Clean Water Rule Response to Comments – Topic 8: Tributaries

87

National Sorghum Producers (Doc. #10847)

8.92 Significant Nexus Test is not Fully Applied

Third, the significant nexus test under the proposed rule does not appear to be applied in 

determining whether tributaries are waters of the United States but rather the existence of 

a bed, banks, and an ordinary high water mark is regarded as sufficient...

But, again, in Rapanos, Justice Kennedy wrote that, in SWANCC, “the Court held...that 

to constitute “navigable waters” under the Act, a water or wetland must possess a 

“significant nexus” to waters that are or were navigable in fact or that could reasonably 

be so made.” However, under the proposed rule, all tributaries and adjacent waters as 

cavernously defined, are off the hook from having to bear any significant nexus to an 

authentically jurisdictional water...

Our assertion here is not necessarily that Justice Kennedy articulated the true reaches of 

the Clean Water Act in Rapanos but rather to point out that beyond far exceeding 

textbook definitions of terms and the reaches of federal jurisdiction according to the 

plurality opinion in Rapanos, the proposed rule appears to also vastly exceed the extra 

latitude that Justice Kennedy was extending. In so doing, we believe that federal and 

constitutional considerations and the private property rights of our producer members are 

at stake here. (p. 5)

Agency Response: Section III(C) of the preamble and Section VII of the Technical 

Support Document discuss the science supporting the agencies’ determination that 

waters meeting the definition of “tributary” have a significant nexus because they 

significantly affect the chemical, physical, and biological integrity of traditional 

navigable waters, interstate waters, and the territorial seas. Similarly, section 

IV(G) of the preamble and section VIII of the Technical Support Document discuss 

“adjacent waters.” Section I of the Technical Support Document describes the legal 

basis of the final rule, including its consistency with the statute and case law.

Nebraska Cattlemen (Doc. #13018)

8.93 Much of the cause for unlawful expansion of jurisdiction is due to the broad scope of 

definitions contained in the proposed rule. The definition of "tributary" is overly broad. 

As proposed, the definition is a land feature which has two banks, a bed and a high water 

mark. The land feature does not lose its tributary status if there are man-made breaks 

(bridges, culverts, etc.) so long as the bed and bank can be identified upstream and 

downstream of the break. And, a tributary can be natural, man-altered, or man-made and 

includes rivers, streams, lakes, impoundments, canals, and ditches (unless excluded).

In direct contradiction to this definition the proposed rule also states, a tributary need not 

even have two banks, a bed and a high water mark if the water feature contributes flow 

directly or through another water to a traditionally navigable water. (Proposed rule at 

22241). The definition also goes on to include isolated water features that might 

somehow be connected through groundwater to a traditionally navigable water. Lastly, 

EPA has entirely excluded any consideration of flow or impact to traditionally navigable 

waters, by including in the definition of tributaries intermittent and ephemeral streams. 

(Proposed rule at 22206). Clearly the plain sense reading of the definition of tributary is 

virtually limitless in its jurisdictional application.
Clean Water Rule Response to Comments – Topic 8: Tributaries

88

There are many examples in Nebraska of waterways that have a bed and bank and a high 

water mark but only run during precipitation events. And, unless there is a significant 

amount of precipitation, many of those examples are waters that flow only a short 

distance before evaporating or seeping into the ground. Many rarely, if ever, have flow 

that actually reaches a flowing stream. This is especially true in the more arid western 

part of the state. (p. 9)

Agency Response: See summary response for section 8.1. Section III(C) of the 

preamble and Section VII of the Technical Support Document discuss the science 

supporting the agencies’ determination that waters meeting the definition of 

“tributary” have a significant nexus because they significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas.

Missouri Agribusiness Association (Doc. #13025)

8.94 Regarding tributaries, the proposed rule states that "while the agencies have not defined 

tributary in any previous regulation, this proposed definition is consistent with longstanding practice and historical implementation of CWA programs." The key point here 

is that the 'long-standing practices' that many were unaware of is now being codified in 

rulemaking and is counter to law and rulings of the Supreme Court. (p. 4)

Agency Response: Section I of the Technical Support Document reviews the 

historic scope of the existing regulatory definition of “waters of the United States” 

and also describes the legal basis of the final rule, including its consistency with the 

statute and case law.

North American Meat Association and American Meat Institute (Doc. #13071)

8.95 --The proposal, if adopted, however, would 1) be an unjustified expansion of Clean 

Water Act (CWA) jurisdiction beyond the limits established by Congress and affirmed by 

the courts and 2) create more uncertainty and confusion for entities subject to CWA 

regulation and those that have not.

For example, EPA recently developed and released detailed maps showing more than 8.1 

million miles of rivers and streams across the 50 states subject to CWA regulation under 

the revised “waters of the United States” (WOTUS) definition. Those values dwarf the 

3.5 million miles estimate of currently regulated waters as detailed in EPA’s January 

2009 report to Congress. This increase represents an expansion in federally jurisdictional 

“ of tributary” miles of at least 130%. For the reasons set forth below, AMI and NAMA 

oppose the proposed rule and urge the agencies to withdraw it. (p. 2)

Agency Response: Section I of the Technical Support Document describes the 

legal basis of the final rule, including its consistency with the statute and case law. 

The agencies do not have maps illustrating the extent of jurisdictional waters of the 

United States. Determining the jurisdictional status of a water feature often 

requires site specific knowledge. Although the final rule provides increased clarity 

and “bright line” distinctions to help differentiate waters of the United States from 

non-jurisdictional features, it will not eliminate the need for consideration of site 

specific knowledge. The agencies generally only conduct jurisdictional 
Clean Water Rule Response to Comments – Topic 8: Tributaries

89

determinations at the request of individual landowners, thus we do not have maps 

depicting the geographic scope of the CWA. Such maps do not exist and the costs 

associated with a national effort to develop them are cost prohibitive and would 

require access to private property across the country. The U.S. Geological Survey 

and the U.S. Fish and Wildlife Service collect information on the extent and location 

of water resources across the country and use this information for many nonregulatory purposes, including characterizing the national status and trends of 

wetlands losses. This data is publicly available and the agencies have relied on 

USGS and USFWS information to characterize qualitatively the location and types 

of national water resources. This information is depicted on maps but not for 

purposes of quantifying the extent of waters covered under CWA regulatory 

programs.

Illinois Corn Growers Association (Doc. #13996)

8.96 None of the following should be categorically considered jurisdictional waters of the 

United States: includes intermittent and ephemeral tributaries; man-made ditches, 

including ditches constructed in dry lands and drain only dry lands or ditches dug in dry 

lands which do not flow all the time or do not flow into a jurisdictional water; normal 

farming and ranching water-related activities such as irrigation which are not regulated 

under the CWA; wet areas on fields or erosional features on fields; farm ponds; 

impoundments with any of the foregoing features; and adjacent wetlands or any other 

waters adjacent to such features (whether in floodplain or riparian areas or otherwise 

physically proximate with some hydrological connection). (p. 3)

Agency Response: See summary response for section 8.1. Section III(C) of the 

preamble and Section VII of the Technical Support Document discuss the science 

supporting the agencies’ determination that waters meeting the definition of 

“tributary” have a significant nexus because they significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas. Paragraph (b) of the final rule excludes many features, 

including most ditches that are not relocated tributaries or excavated in tributaries, 

artificial lakes and ponds created in dry land and used primarily for such uses as 

stock watering or irrigation, and erosional features that do not meet the definition of 

“tributary” in the final rule. See section IV(I) of the preamble. Additionally, all 

statutory exemptions, including those exempting normal farming, silviculture and 

ranching activities from CWA section 404 permitting, remain in effect and 

unchanged by the final rule.

Indiana Farm Bureau, Inc. (Doc. #14124)

8.97 According to the online version of Merriam-Webster1, a “tributary” is “a stream that 

flows into a larger stream or river or into a lake.” This is a logical definition and one that 

is generally understood. This stands in stark contrast to the proposed definition of “a 

water physically characterized by the presence of a bed and banks and ordinary high 

water mark... which contributes flow, either directly or through another water” to a 

jurisdictional water. 79 Fed Reg. at 22,263. This definition is so expansive that it includes 
Clean Water Rule Response to Comments – Topic 8: Tributaries

90

features which are ephemeral in nature and those which would normally be considered 

ditches or erosional features.

The expansive reach of this definition is demonstrated by activities in southern Indiana 

related to construction of I-69. As one drives down the newly constructed interstate, the 

side of the road is regularly marked with white signs in black letters that state 

“JURISDICTIONAL WATER.” From the road, those signs appear to be frequently 

placed along the valleys between small ridgelines in which water is channeled during 

storms. There is no doubt they are ephemeral in nature. Those areas are covered in 

vegetation, yet they are jurisdictional. If those areas are jurisdictional, there would seem 

to be no limit to what will be claimed to have a bed and bank and ordinary high water 

mark. As noted by the plurality in Rapanos, in defining what may be a “water of the US,” 

the phrase “does not include channels through which water flows intermittently or 

ephemerally, or channels that periodically provide drainage for rainfall.” 547 U.S. at 739. 

Justice Kennedy, in his separate opinion, noted that “mere hydrologic connection should 

not suffice in all cases: the connection may be too insubstantial for the hydrologic linkage 

to establish the required nexus with navigable waters.” Id. at 784-85. In summary, we 

believe that the interpretation given to declare all “tributaries” to be jurisdictional is not 

consistent with the principles established by the U.S. Supreme Court. (p. 2-3)

Agency Response: See summary response for section 8.1. Paragraph (b) of the 

final rule excludes many features, including most ditches that are not relocated 

tributaries or excavated in tributaries, as well as erosional features that do not meet 

the definition of “tributary” in the final rule. Tributaries are discussed in section 

IV(F) of the preamble and section VII of the Technical Support Document. Section 

I of the Technical Support Document describes the legal basis of the final rule, 

including its consistency with the statute and case law.

Irvine Ranch Water District (Doc. #14774)

8.98 CWA jurisdiction should be limited to the surface expression of natural waters and 

wetlands on a project site, including on-site tributaries. Applicants should not be required 

to provide information on upstream tributaries unless they are trying to prove that a 

surface expression on site has no connectivity to a natural tributary and is therefore nonjurisdictional. (p. 6)

Agency Response: In this final rule, EPA and the Corps clarify the scope of 

“waters of the United States” that are protected under the CWA, using the text of 

the statute, Supreme Court decisions, the best available peer-reviewed science, 

public input, and the agencies’ technical expertise and experience in implementing 

the statute. This rule makes the process of identifying waters protected under the 

CWA easier to understand, more predictable, and consistent with the law and peerreviewed science, while protecting the streams and wetlands that form the 

foundation of our nation’s water resources. The final rule does not change the way 

jurisdictional determinations will be processed by the Corps, where insufficient 

information is provided by the requesting party, whether that be information about 

the specific site or the landscape and watershed context of the site, the Corps will 

gather the information necessary to make a decision. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

91

Iowa Farmers Union (Doc. #15007)

8.99 The proposed rule is the first time that EPA and the Corps have proposed a regulatory 

definition of "tributary," and in general, we support the creation of clearly defined per se 

categories of jurisdictional waters to promote increased regulatory certainty. However, 

the proposed definition of "tributary" has led to considerable confusion and concern 

among farmers particularly regarding the inclusion of wetlands, lakes, and ponds that 

lack the specific enumerated features of a tributary (bed, banks, and an ordinary high 

water mark). To further the goal of crafting an easily applied bright-line rule, we propose 

incorporating the following changes in the final rule:

 Include the plain language definition of "ordinary high water mark" in the text of 

the rule, rather than referring back to another regulation.

 Clarify that the specific enumerated features of a tributary (bed, banks and an 

ordinary high water mark) take years to form, and that the rule will not regulate 

temporary accumulations of water resulting from isolated events, such as heavy 

precipitation.

 As part of the non-exhaustive list of examples of regulated tributaries (rivers, 

streams, lakes, ponds, impoundments, canals, and ditches), specify that regulated 

ditches are only those ditches that are constructed through a wetland or stream 

and that have a perennial flow. Agricultural drainage ditches have been a 

particularly sore topic among farmers in discussing the proposed rule, and any 

additional clarity that can be directly incorporated into the language of the final 

rule on this topic would be extremely helpful. 

 Limit the definition of "tributary" to those waters that actually have a bed and 

banks and an "II ordinary high water mark. Wetlands and other waters lacking 

these features can be adequately covered as either "adjacent waters" under 

paragraph (6), or on a case-by-case basis pursuant to the "significant nexus" text 

under paragraph (7). Including wetlands and other waters with no bed or banks or 

ordinary high water mark within the definition of "tributary" undermines the goal 

of creating a clear, bright-line rule, making it more difficult for the regulated 

community to easily apply the rule, and is not necessary to the overall goal of 

protecting and enhancing water quality. (p. 5)

Agency Response: See summary response for section 8.1.

J.R. Simplot Company (Doc. #15062)

8.100 In the proposed rule, the agencies claim jurisdiction broadly over all tributaries with no 

site-specific analysis needed. The agencies, in the proposal, have declared anything with 

a bed, bank and OHWM that might ever contribute flow to be a jurisdictional water; the 

proposed rule would make all tributaries "waters of the U.S."

Under the current guidance, tributaries that flow greater than 90-days/year to a TNW are 

jurisdictional, while tributaries that typically flow less than 90-days/year have to meet the 

significant nexus criteria (the current, not proposed, definition) to be considered waters of 

the U.S. Under the proposed rule, tributaries also include wetlands, lakes, and ponds, 

even if they lack a bed and bank ordinary high watermark (OHWM), if they contribute 
Clean Water Rule Response to Comments – Topic 8: Tributaries

92

flow, either directly or indirectly, to jurisdictional water. The potential impact of this rule 

are shown in these examples.

Example 1: A remote ephemeral drainage that carries water infrequently (i.e., during 

large storm events) and does not have a defined bed and bank throughout it (but does in 

some places), would be a tributary and categorically a water of the U.S. under the 

proposed rule.

Example 2: Is a livestock watering pond that is in a remote area within an ephemeral 

drainage, and that at times could overflow water back into the drainage, be a water of the 

U.S.? The exemption states “artificial lakes or ponds created by excavating and/or dry 

diking land and used exclusively for purposes as stock watering, irrigation, settling 

basins, or rice growing.” If a pond is within an ephemeral drainage (as the case for many 

watering ponds in remote areas in the West, the in appears to be classified as a water of 

the U.S. under the proposed rule.

For example 1, a review of a 3,000 acre potential mineral extraction area located in the 

arid West, that has a number of ephemeral natural depressions and drainage pathways, 

shows that number of acres considered "waters of the U.S." will double under this 

proposed rule. Such pathways may have water in them for a period of just several days or 

weeks during snowmelt or intense rain storms; such waters may never actually 

flow/connect with a perennial stream. And there is no aquatic community present in such 

pathways, rather just barren earth and typical high desert steppe vegetation (an example 

being sagebrush). Defining such landscape features as 'waters of the U.S." defies reason.

Livestock watering ponds (example 2) are often built in ephemeral drainages. The 

purpose of such ponds is to capture the snowmelt and rain events for the purpose of 

providing water for livestock throughout the spring and summer. Under the definitions 

proposed in the rule, such ponds would be considered "waters of the U.S." making them 

subject to water quality standards among other requirements. Once again, this defies 

reason; these are man-made ponds made for very specific purpose. Also, this proposed 

rule would likely hinder new livestock pond creation as the construction of such ponds 

would likely have to go through Section 404 permitting.

Having this broad definition of "tributaries" will have a significant impact and burden on 

businesses that utilize the landscape (i.e., ranching and mining being two examples). (p. 

4)

Agency Response: See summary response for section 8.1. Paragraph (b) of the 

final rule excludes many features, including most ditches that are not relocated 

tributaries or excavated in tributaries, artificial lakes and ponds created in dry land 

and used primarily for such uses as stock watering or irrigation, and erosional 

features that do not meet the definition of “tributary” in the final rule. 

Additionally, all statutory exemptions, including those exempting normal farming, 

silviculture and ranching activities from CWA section 404 permitting, remain in 

effect and unchanged by the final rule.

Klamath Water Users Association (Doc. #15063)

8.101 The agencies should provide assurances in a final rule that the definition of “tributary” 

will be limited to those with “bed and banks with an ordinary high water mark” that have 
Clean Water Rule Response to Comments – Topic 8: Tributaries

93

formed over several years and that would not include systems or facilities developed for 

irrigation water or agricultural drainage conveyance. Definitions must be further clarified 

for the terms “ordinary high water mark,” “bed and banks,” and other terminology used 

in the proposed rule that can and will cause uncertainty in the implementation of a final 

rule.

Jurisdictional tributaries should meet a new bright line test related to the size of bed and 

banks, amount of flow, or distance from the jurisdictional navigable water in order to be 

considered a “water of the U.S.” This test would establish a limit on just how small or 

dry, or how far upstream, the tributary can be from the traditionally jurisdictional water 

for the CWA to apply... (p. 5)

Agency Response: See summary response for section 8.1, as well as the summary 

response for Section 6.2 of this RTC, “Excluded Ditches.” The term “ordinary high 

water mark” has been defined in Corps regulations since 1986, and used by Corps 

Districts nationwide to determine the lateral limits of jurisdiction over non-tidal 

water bodies for the CWA section 404 permitting program. As described in the 

preamble, for purposes of the rule, “bed and banks” means the substrate and sides 

of a channel between which flow is confined. The banks constitute a break in slope 

between the edge of the bed and the surrounding terrain, and may vary from steep 

to gradual. 

Colorado Cattlemen's Association (Doc. #15068)

8.102 CCA assert that the agencies' definition of "tributary" is a limitless category that has the 

potential to wrap every natural pond, isolated wetland, or ditch into the federal regulatory 

scheme, which violates the language and spirit of the Supreme Court's decisions in 

SWANCC and Rapanos.

86

 It is clear that the phrase "waters of the U.S." is not limitless, 

yet that is exactly what the agencies have proposed through their broad and ill-defined 

term "tributary." Key phrases have been left undefined. The definition for "through 

another water," a key phrase in the definition, was simply left out by the agencies. Not 

only does this foster confusion instead of clarity in the regulated community, it could be 

stretched by regulators or litigants now or in the future. If the agencies' intent was not to 

create such a broad definition, than they should have put such intent in the regulation.

The agencies have excluded consideration of flow, making the definition completely 

dependent on land features, not actual water. And even with regard to the land features, 

the agencies contradict themselves. The agencies state that a tributary needs a bed, bank 

and OHWM but then turned around in the next sentence and contradicted themselves, 

saying that in fact a regulator does NOT need to find a bed, bank or OHWM to find a 

jurisdictional tributary. (Proposed Rule at 22241). Again, these contradictions only 

provide added confusion.

 

86 Rapanos v. United States, 547 U.S. 715 (2006); (1. Scalia, Indicating "navigable" invokes a limit on the CWA

jurisdiction the plurality stated " ...that the qualifier "navigable" is not devoid of significance ...the waters of the

United States in 1362(7) cannot bear the expansive meaning that the Corps would give it"); SWANCC v. Us. Army

Corps of Engineers, 531 U.S. 159 (2001); (In striking down the agencies' Migratory Bird Rule the court stated, "we

find nothing approaching a clear statement from Congress that it intended 404(a) to reach an abandoned sand and

gravel pit such as we have here").
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94

The agencies cannot categorically make anything with a bed, bank and OHWM that takes 

water somewhere downstream jurisdictional. The proposed rule is clear that the definition 

of 'tributary' does in fact include all ephemeral,streams; intermittent and perennial 

features and that rate of flow (or any flow) is simply not a factor. (Proposed Rule at 

22206; (" ...the agencies conclude that tributaries, including headwaters, intermittent, and 

ephemeral streams, and especially when all tributaries in a watershed are considered in 

combination, have a significant nexus to traditional navigable waters, interstate waters, or 

territorial seas ...")). CCA believes that the definition of tributary is overly broad because 

the agencies cannot make all tributaries per se jurisdictional without satisfying the 

significant nexus analysis. (p. 4-5)

Agency Response: The agencies disagree that the definition of "tributary" is a 

limitless category that will include every natural pond, isolated wetland, or ditch.

See summary response for section 8.1. Tributaries are discussed in section IV(F) of 

the preamble and section VII of the Technical Support Document. The definition of 

“adjacent waters” in the final rule has been revised and clarified. See section IV(G)

of the preamble and section VIII of the Technical Support Document. Section I of 

the Technical Support Document describes the legal basis of the final rule, including 

its consistency with the statute and case law.

American Forest Foundation (Doc. #15093)

8.103 ...by defining “all tributaries” as WOTUS including man‐made ditches, and certain lands 

adjacent to tributaries such as riparian areas and floodplains, the proposed rule would 

significantly increase the reach of federal jurisdiction, regardless of whether or not the 

tributary has a significant nexus to, or relative permanence of, water. We would 

encourage you to more clearly define “all tributaries.” (p. 4)

Agency Response: See summary response for section 8.1. Tributaries are 

discussed in section IV(F) of the preamble and section VII of the Technical Support 

Document. The definition of “adjacent waters” in the final rule has been revised 

and clarified. See section IV(G) of the preamble and section VIII of the Technical 

Support Document. Section I of the Technical Support Document describes the legal 

basis of the final rule, including its consistency with the statute and case law.

El Dorado Irrigation District, Placerville, California (Doc. #15231)

8.104 Extending the definition of tributaries to man-made, non-stream conveyances is 

unnecessary because such conveyances may already be regulated as point sources when 

they add pollutants to waters of the United States. The proposed rule's justification for 

extending the definition of tributaries to man-made, non-stream conveyances fails to 

recognize important distinctions between CWA sections 402 and 404. The Supreme 

Court and the Ninth Circuit Court of Appeals have noted that the definition of "waters of 

the United States" for both sections 402 and 404 is functionally equivalent. (See 

Rapanos, 547 U.S. at 742; San Francisco Baykeeper, et al. v. Cargill Inc., 481 F.3d 700, 

705, 704, n.4 (9th Cir. 2007).) Nevertheless, there are important distinctions between the 

two sections. Section 402 is an exception to the general prohibition against the discharge 

of any pollutant to navigable waters. (33 U.S.C. § l 342(a).) That section allows for the 

discharge of pollutants from point sources by permit and is primarily concerned with 
Clean Water Rule Response to Comments – Topic 8: Tributaries

95

regulation of pollution-which when discharged into waters of the United States, travels 

downstream. (Id. at § 1342(a); Rapanos, 547 U.S. at 744-745.) By contrast, section 404, 

which allows for the discharge of dredged or fill material, is primarily concerned with the 

regulation of material "which is typically deposited for the sole purpose of staying put, 

[and] does not normally wash downstream ...." (Rapanos, 547 U.S. at 744.) This 

distinction is important because, as discussed more fully below, the requirements of 

section 402 may still apply to man-made, non-stream conveyances that are not 

themselves jurisdictional, whereas, the requirements of section 404 do not.

The Supreme Court has noted that "there is no reason to suppose that our construction [of 

'waters of the United States' under section 404] significantly affects the enforcement of § 

[402] .... The [CWA] does not forbid the 'addition of any pollutant directly to navigable 

waters from any point source,' but rather the 'addition of any pollutant to navigable 

waters.' " (Id., emphasis in original.) Consequently, a water body that is nonju1isdictional 

under section 404, may still be subject to EPA's enforcement authority under section 402. 

For example, it is possible that a pollutant discharged to an intermittent channel such as a 

gully, rill, or non-wetland swale (not considered "waters of the United States" even under 

the proposed rule (79 Fed. Reg. 76, 22 199)) may eventually wash downstream into 

navigable water. Even though the channel to which the pollution was originally 

discharged does not constitute "waters of the United States," EPA may still regulate such 

a discharge because it constitutes the addition of a pollutant to navigable waters. 

(Rapanos, 547 U.S. at 743.)

The Supreme Court noted that, in fact, some courts have held that upstream 

inte1mittently flowing channels themselves constitute point sources under the Act. 

(Rapanos, 547 at 743 (citing 33 U.C.S. § 1362(14); United States v. Ortiz, 427 F.3d 

1278, 1281 (l01 h Cir. 2005) (a storm drain that carried flushed chemicals from a toilet to 

the Colorado River was a "point source").) A point source need not be the original source 

of the pollutant; it need only convey the pollutant to navigable waters. (South Fla. Water 

Management Dist. v. Miccosukee Tribe, 541 U.S. 95, 105 (2004).) 

Thus, characterizing man-made, non-stream conveyances as tributaries is unnecessary for 

subjecting them to the permitting requirements of section 402. Such facilities, when 

discharging pollutants to waters of the United States (which may affect the physical, 

chemical, or biological integrity of navigable waters), constitute point sources that are 

subject to the permitting requirements of section 402, whether or not they constitute 

tributaries under the definition of waters of the United States. Such man-made, nonstream conveyances, however, should not automatically be subject to the permitting 

requirements of section 404 because the discharge of "fill" material does not necessarily 

affect the physical, chemical, or biological integrity of navigable waters that might be 

located some distance downstream. For example, replacing a length of pipe on a flume 

(such as those found on EID's Project 184) that may indirectly contribute flow to a 

traditional navigable water, does not affect the chemical, physical, or biological integrity 

of that water.

In this sense, the proposed rule would unnecessarily expands jurisdiction of "tributaries" 

to manmade facilities simply because they are capable of conveying pollution to 

navigable waters. (p. 6-8)
Clean Water Rule Response to Comments – Topic 8: Tributaries

96

Agency Response: See summary response for section 8.1. Section I of the 

Technical Support Document provides the legal framework under which a ditch 

could be considered both a point source and a water of the United States. 

Paragraph (b) of the final rule excludes many features, including most ditches that 

are not relocated tributaries or excavated in tributaries. Section I of the Technical

Support Document describes the legal basis of the final rule, including its 

consistency with the statute and case law.

Union County Cattlemen (Doc. #15261)

8.105 FR Page 22205 More generally, in addition to providing critical habitat for complex life 

cycle completion, tributaries provide refuge from predators and adverse physical 

conditions in rivers, and they are reservoirs of genetic- and species-level diversity. These 

connections between tributaries and (a)(1) through (a)(3) waters significantly influence 

the biologic integrity of these waters. Tributaries have important effects on the biological 

integrity of(a)(1) through (a)(3) waters, contributing materials to downstream food 

networks and supporting populations for aquatic species, including economically 

important species such as salmon, etc.,

Comment: We disagree and find the information about critical habitat to be a stretch 

across the country. All tributary connections do not have a significant influence on the 

biologic integrity of the waters. This is an over -blown statement and exaggeration of the 

science research results. (p. 1)

Agency Response: See summary response for section 8.1 and section VII of the 

Technical Support Document.

Weyerhaeuser Company (Doc. #15392)

8.106 The proposed rule’s new definition of “tributary” and the categorical assertion of 

jurisdiction over all water features that meet that definition go too far. The Agencies 

should withdraw the proposed definition and instead adopt a standard that: (i) includes 

bright-line, objective scientific standards for identifying tributaries with a significant 

nexus to navigable waters; (ii) is not dependent on an overly broad categorical 

determination that effectively cannot be rebutted; and (iii) does not depend upon a flawed 

interpretation of the significant nexus test. (p. 6)

Agency Response: See summary response for section 8.1.

Minnesota Soybean Growers Association (Doc. #15542)

8.107 The definition of "tributary" is confusing and circular. The definition uses terms such as 

"another water" which is not defined. There is no guidance as to whether "another water" 

has to be a WOTUS or can be an exempted water. It is hard to imagine that a water that is 

connected through a non-WOTUS can then itself be a WOTUS and not be confusing or 

take a great deal of hours of staff time to determine. The definition also states that there 

needs to be a "bed and banks and ordinary high water mark." Except, those requirements 

are not required for "wetlands, lakes and ponds." The rule is unclear then if a wetland was 

drained 100 years ago and is now "prior converted cropland" if it is a tributary since that 

designation is forever, or if it is exempted from the rule. How the designation of 
Clean Water Rule Response to Comments – Topic 8: Tributaries

97

"tributary" actually works with and "compares to the exemptions should be better 

defined. This definition adds uncertainty to the rule and invites litigation. Every area that 

is poorly defined or drafted is another potential Supreme Court case that could take years 

and years to resolve with no set answer to what a WOTUS actually is under the CWA... 

(p. 2)

Agency Response: Section III of the preamble and section II of the Technical 

Support Document address “significant nexus” evaluations as they pertain to 

connections provided by non-jurisdictional waters. See summary response for 

section 8.1. Paragraph (b) of the final rule excludes many features of concern to the 

agriculture community. Such exclusions include prior converted cropland, most 

ditches that are not relocated tributaries or excavated in tributaries, artificially 

irrigated areas that would revert to dry land should application of water to that 

area cease, artificial lakes and ponds created in dry land and used primarily for 

such uses as stock watering or irrigation, and erosional features that do not meet the 

definition of “tributary” in the final rule. Paragraph (b) also makes it clear that the 

features identified therein “are not waters of the United States even where they 

otherwise meet the terms of paragraphs (a)(1) through (a)(8)” of the rule. Thus, any 

feature excluded under paragraph (b) may not be considered waters of the United 

States under any other provision of the rule. Additionally, all statutory exemptions, 

including those exempting normal farming, silviculture and ranching activities from 

CWA section 404 permitting, remain in effect and unchanged by the final rule.

Alabama Farmers Federation (Doc. #16539)

8.108 Ephemeral streams would be regulated as a "tributary" under this rule. Ditches that are 

dry most of the year would be categorically regulated as a ''tributary'' under this rule if 

they ever carry any amount water that eventually flows to a traditionally defined 

"navigable" water. Low areas or depressions in a farm field that the agencies deem as 

being adjacent to jurisdictional waters or located in a floodplain would be regulated as 

well. In addition, the concept of "significant nexus" as defined by the agencies in the 

proposed rule would allow for the regulation of virtually any other feature not 

specifically or categorically defined as a water of the United States by the rule. 

Collectively, this rule would give the agencies the ability to regulate virtually every 

isolated wetland, pond, ditch or low area on farms across the country. (p. 1)

Agency Response: See the summary response for section 8.1 for a general 

description of the definition of “tributary” in the final rule. Paragraph (b) of the 

final rule excludes many features of concern to the agriculture community. Such 

exclusions include prior converted cropland, most ditches that are not relocated 

tributaries or excavated in tributaries, artificially irrigated areas that would revert 

to dry land should application of water to that area cease, artificial lakes and ponds 

created in dry land and used primarily for such uses as stock watering or irrigation, 

and erosional features that do not meet the definition of “tributary” in the final rule. 

Paragraph (b) also makes it clear that the features identified therein “are not waters 

of the United States even where they otherwise meet the terms of paragraphs (a)(1) 

through (a)(8)” of the rule. Thus, any feature excluded under paragraph (b) may 

not be considered waters of the United States under any other provision of the rule. 
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98

Additionally, all statutory exemptions, including those exempting normal farming, 

silviculture and ranching activities from CWA section 404 permitting, remain in 

effect and unchanged by the final rule.

Missouri Corn Growers Association (Doc. #16569)

8.109 The definition of “tributary” creates another boundless regulated category that has the 

potential to bring ponds, isolated wetlands, and dry ditches into federal jurisdiction. This 

definition of tributary will encompass an enormous number of isolated and predominately 

dry features that, for no other reason that practicability, should be far beyond EPA’s 

authority. Appendix A provides images of several features that are common in fields 

across Missouri. (p. 4)

Agency Response: The agencies disagree that the definition of “tributary” in the 

final rule will categorically bring ponds, isolated wetlands and dry ditches into 

federal jurisdiction. See the summary response for section 8.1 for a general 

description of the definition of “tributary” in the final rule. Paragraph (b) of the 

final rule excludes many features of concern to the agriculture community. Such 

exclusions include prior converted cropland, most ditches that are not relocated 

tributaries or excavated in tributaries, artificially irrigated areas that would revert 

to dry land should application of water to that area cease, artificial lakes and ponds 

created in dry land and used primarily for such uses as stock watering or irrigation, 

and erosional features that do not meet the definition of “tributary” in the final rule. 

Agribusiness Association of Kentucky et al. (Doc. #18005)

8.110 The Agencies' stated goal for this rule is to provide "clarity" and reduce the confusion, 

red tape and uncertainty allegedly caused by the Supreme Court over what waters are 

jurisdictional. This proposal, however, clarifies only that the Agencies could regulate 

almost any low spot on a farmer's field where water sometimes stands or channels. The 

proposal would categorically regulate as "navigable waters" countless ephemeral 

drainages, ditches and other features across the countryside that are wet solely from 

precipitation and may be miles from the nearest truly "navigable" water. It would also 

regulate small, remote "wetlands"—which may look like nothing more than low spots on 

a farm field — just because those areas happen to be near a jurisdictional ditch or 

ephemeral, or located in a floodplain.

The proposal does not provide clarity to farmers and ranchers; it only exposes them to 

unknowing violations of the law by farming in, and discharging typical farm nutrients 

and pesticides into, features that look more like land than water. Because farmers and 

ranchers can be liable for heavy CWA civil and even criminal fines and jail time for 

unlawful discharges to "navigable waters," they must be able understand how that term 

applies to their land.

... The Agencies also provide an incomplete description to the general public about what 

types of waters the Agencies intend to regulate. EPA's marketing campaign provides 

images of flowing rivers, streams and marshes teeming with wildlife and recreational 

activity. These waters bear no resemblance to the majority of the features that the rule 

would regulate as "tributaries," wetlands or ponds. Typical features on farms and across 

the countryside include low areas that collect water from local drainage and over time 
Clean Water Rule Response to Comments – Topic 8: Tributaries

99

develop wetland characteristics.87 Others are subtle channels formed by rolling hills or 

even more subtle changes in elevation, where water naturally channels when it rains. Just 

as common are ditches that carry water only when it rains but that fall outside proposed 

ditch exclusion because they contain wetlands somewhere along their length, or because 

they sometimes receive stormwater flows from nearby ephemeral drains or wetlands. 

These are all common features found on our nation's farms and ranches, and they will all 

be open to regulation under the proposed rule.

The proposed rule will cause continued confusion over the boundaries of federal 

jurisdiction. As explained in the following sections, it provides little clarity in the three 

primary definitional changes described below, each of which results in a significant 

expansion of federal control over land and water resources across the nation. (p. 5-6)

...

Nor can the Agencies point to explicit regulatory language to justify reliance on past 

agency ephemeral streams have historically been regulated and can be WOUS under 

current practice. For example, the Agencies claim to have always regulated ephemeral 

streams. But the term "ephemeral" (unlike the term "intermittent" or "perennial"), which 

is used 75 times in the current proposal, is never mentioned in prior regulations. The text 

and preamble of the current regulations (promulgated in 1986 by the Corps and in 1988 

by EPA) contain no reference to regulating "ephemeral" streams or drainages. Neither do 

the 1977 regulations. Likewise, current and past regulatory text says nothing to suggest 

that ditches are a category of "tributaries." (The Agencies have indicated in past 

preambles that certain ditches may qualify as "navigable waters" on a case-specific basis, 

but they were never categorically defined as "tributaries.") The Agencies have asserted in 

guidance documents and in enforcement actions that certain ditches and "ephemeral 

streams" are subject to CWA jurisdiction, but those are examples of ad hoc "regulatory 

creep," not notice-and-comment rulemaking. In other words, the fact that the Agencies 

have occasionally asserted jurisdiction over these types of features in the past does not 

make it lawful to categorically assert jurisdiction over them now. (p. 5-6, 19)

Agency Response: The agencies do not believe that the final rule will “regulate 

almost any low spot on a farmer's field where water sometimes stands or channels.” 

See the summary response for section 8.1 for a general description of the definition 

of “tributary” in the final rule. Paragraph (b) of the final rule excludes many 

features of concern to the agriculture community. Such exclusions include prior 

converted cropland, most ditches that are not relocated tributaries or excavated in 

tributaries, artificially irrigated areas that would revert to dry land should 

application of water to that area cease, artificial lakes and ponds created in dry land 

and used primarily for such uses as stock watering or irrigation, and erosional 

features that do not meet the definition of “tributary” in the final rule. Paragraph 

(b) also makes it clear that the features identified therein “are not waters of the 

United States even where they otherwise meet the terms of paragraphs (a)(1) 

through (a)(8)” of the rule. Thus, any feature excluded under paragraph (b) may 

not be considered waters of the United States under any other provision of the rule. 

 

87 U.S. Army Corps of Engineers, Wetlands Delineation Manual, January 1987.
Clean Water Rule Response to Comments – Topic 8: Tributaries

100

Additionally, all statutory exemptions, including those exempting normal farming, 

silviculture and ranching activities from CWA section 404 permitting, remain in 

effect and unchanged by the final rule. Section I of the Technical Support 

Document reviews the historic scope of the existing regulatory definition of “waters 

of the United States” and also describes the legal basis of the final rule, including its 

consistency with the statute and case law.

New Mexico Cattle Growers Association et al. (Doc. #19595)

8.111 Specific Concerns and Comments 

i. Section (a)(5) and definition of “tributary”: For legal and scientific clarity, the 

agencies should withdraw the Proposed Rule and replace it with a rule that defines 

tributaries as only those waters that maintain a permanent, surface water connection to an 

(a)(1) or (a)(3) water.

The proposed definition of “tributary” will substantially increase the burdens on our 

nation’s agricultural producers. As currently drafted, the definition includes “ditches” that 

contribute water directly or through another water (even if only intermittently or 

ephemerally) to an (a)(1) through (a)(4) water. 

... Because the determination is automatic, the costs of complying with permitting and 

restrictions should be more properly analyzed. Ephemeral and intermittent waters and 

erosional features that lack permanent surface water connections should be exempted 

from any proposed definition of “tributary.” (p. 11-12)

Agency Response: See summary response for section 8.1. Paragraph (b) of the 

final rule excludes many features from consideration as waters of the United States, 

including most ditches that are not relocated tributaries or excavated in tributaries 

and erosional features that do not meet the definition of “tributary” in the final rule. 

Additionally, all statutory exemptions, including those exempting normal farming, 

silviculture and ranching activities from CWA section 404 permitting, remain in 

effect and unchanged by the final rule.

Georgia Department of Transportation (Doc. #14282.1)

8.112 The proposed rule defines tributaries of certain other waters as jurisdictional by rule and 

includes a new definition of "tributary." We agree with the concept of defining certain 

tributaries as jurisdictional by rule. We also agree that it is appropriate and useful to 

include a definition of the term "tributary" in the regulations. However, we are concerned 

that the proposed rule would, in effect, substantially broaden the universe of tributaries 

that are deemed jurisdictional by rule. We recommend revising the rule to be more 

consistent with the treatment of tributaries in the 2008 Guidance. (p. 5)

Agency Response: See summary response for section 8.1.

Lake Charles Harbor and Terminal District, Louisiana (Doc. #14448)

8.113 The District is concerned that the proposed treatment of "tributary" and "adjacent" waters 

will result in a significant expansion of features (both natural and artificial) subject to 

regulation as "waters of the United States." Definitions like "all tributaries" and "all 
Clean Water Rule Response to Comments – Topic 8: Tributaries

101

waters adjacent" are too broad and could impact port facilities. We recommend 

clarification of these definitions. (p. 2)

Agency Response: The final rule has been revised and clarified in response to 

public comments. See section IV(F) and IV(G) of the preamble to the final rule for 

a discussion of “tributaries” and “adjacent waters,” respectively.

Airports Council International - North America (Doc. #16370)

8.114 In an effort to further understand the jurisdictional reach and related impacts of the 

Proposed Rule the following general questions need to be answered:

...

The definition of tributary seems excessive, especially if there are manmade breaks, 

which under the proposal does not disqualify status. Would complex drainage networks 

in many urban settings be considered tributaries? Does the definition of tributaries 

eliminate many end-of-pipe BMPs or regional approaches to stormwater management 

and treatment? (p. 6-7)

Agency Response: The agencies are unclear what the commenter means in his 

reference to “complex drainage networks in urban settings” or “end-of-pipe BMPs.” 

Paragraph (b) of the final rule excludes many features from consideration as waters 

of the United States, including stormwater control features created in dry land.

Mohave Electric Cooperative, Inc. (Doc. #10953)

8.115 The Agencies assert that one of the primary purposes of the Proposed Rule is to provide a 

level of clarity regarding the extent of waters of the U.S. that both the regulated public 

and the Supreme Court have demanded. However, despite the broad conclusion in the 

Proposed Rule that "[m]ost prairie streams and southwest intermittent and ephemeral 

streams are likely to be considered tributaries to (a)(1) through (a)(3) waters....", and that 

tributaries are, by definition, jurisdictional under the Proposed Rule, the extent of federal 

jurisdiction over non-navigable tributaries is still very much in question. 

Tributaries are defined in the Proposed Rule as "a water physically characterized by the 

presence of a bed and banks and ordinary high water mark, as defined at 33 CFR 

328.3(e), which contributes flow, either directly or through another water, to a water 

identified in paragraphs (a)(1) through (4)." However, as noted right in the definition of 

"tributary", only the term "ordinary high water mark" is defined in the regulations. The 

Agencies make no attempt to define "bed and bank" or, more problematically, 

"contributes flow". (p. 3-4)

Agency Response: As described in the preamble, for purposes of the final rule, 

“bed and banks” means the substrate and sides of a channel between which flow is 

confined. The banks constitute a break in slope between the edge of the bed and the 

surrounding terrain, and may vary from steep to gradual. Section IV(F) of the 

preamble describes that a water that does not contribute flow to a traditional 

navigable water, interstate water or the territorial seas is fundamentally not a 

“tributary” by definition in the final rule.
Clean Water Rule Response to Comments – Topic 8: Tributaries

102

Duke Energy (Doc. #13029)

8.116 Duke Energy recommends that the agencies reexamine the definition for tributary and 

modify it to represent actual tributaries that have the requisite relationship with TNWs 

and the meet the requirements set for in Rapanos. In general, this category of water 

should not include impoundments; lentic-type waters (lakes, ponds, or wetlands) whether 

natural, man-made or man-altered; or ephemeral waters. In addition, the definition should 

remove the references to man-made or natural breaks since there is no evidence that these 

categorically have significant physical, chemical, and biological effects on downstream 

traditional navigable waters. The definition for tributary should also remove the explicit 

references to ditches as tributaries. (p. 26) 

Agency Response: See summary responses for Section 8.1 and 8.1.1. The final 

rule categorically considers tributaries, as defined in the rule that are not otherwise 

excluded under paragraph (b) to be waters of the United States. Section III(C) of 

the preamble and Section VII of the Technical Support Document discuss the 

science supporting the agencies’ determination that waters meeting the definition of 

“tributary” have a significant nexus because they significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas. Paragraph (b) of the final rule excludes many features from 

consideration as waters of the United States, including most ditches that are not 

relocated tributaries or excavated in tributaries. 

Peabody Energy (Doc. #13560)

8.117 Although the stated purpose of the rule is to clarify jurisdiction, the proposed rule is 

confusing and contradictory both within the document and in light of public statements 

by the Environmental Protection Agency (EPA) and the ACOE about the rule. The EPA 

and ACOE publicly state that tributaries must have a bed and bank and ordinary high 

water mark (OHWM) to be jurisdictional. However, the proposed rule states that a 

tributary is anything that connects downstream, including ponds, canals, concrete 

channels and manmade ditches. The connection does not have to be direct but can be 

through groundwater, occasional pond overflow or flows that occur on a limited basis. 

Based on the subjective language in the proposed rule, arguably anything can be called a 

tributary. Tributaries are jurisdictional per se as opposed to applying the significant nexus 

test as is currently required. The proposed rule repeatedly points to importance and use of 

the OHWM. However, it is difficult to evaluate the effect of this variable because the 

definition keeps changing. The latest version was quietly placed on the ACOE's website 

only a few weeks ago. The proposed rule claims to increase clarity but asks for comments 

on the definition of gullies, how to determine adjacent, the use of significance, vernal 

pools, how to determine floodplain size, etc. The lack of definition of critical components 

of the proposed rule not only makes evaluation of its impacts virtually impossible but 

also eliminates the possibility of clarity in implementation. (p. 1)

Agency Response: See summary response for Section 8.1, 8.1.2and 8.3. The final 

rule contains a definition of tributary which was modified in response to comments 

to provide increased clarity. As described in the summary response for Section 8.1, 

the final rule clearly requires the presence of both bed and banks and another 

indicator of OHWM, if one is not present then the water does not qualify as a 
Clean Water Rule Response to Comments – Topic 8: Tributaries

103

tributary. Wetlands, lakes, ponds, and other features lacking a bed and banks 

and/or OHWM are no longer defined as tributaries in the Final Rule, but may be 

considered jurisdictional “waters of the United States” as adjacent waters or 

similarly situated waters with a significant nexus to (a)(1) through (3) waters. The 

term “ordinary high water mark” has been defined in Corps regulations since 1986, 

and used by Corps Districts nationwide to determine the lateral limits of jurisdiction 

over non-tidal water bodies for the CWA section 404 permitting program. Section I 

of the Technical Support Document describes the legal basis of the final rule, 

including its consistency with the statute and case law.

Florida Power and Light Company (Doc. #13615)

8.118 ...the proposed definitions of tributary should be revised as follows to make clear that the 

wastewater treatment exclusion applies regardless of other aspects of the rule, with 

additions in underlined bold and deletions shown in strikethrough: 

(5) Tributary. The term tributary means a water physically characterized by the 

presence of a bed and banks and ordinary high water mark, as defined at 33 CFR 

328.3(e), which contributes flow, either directly or through another water, to a 

water identified in paragraphs (a)(1) through (4) of this section provided that 

hydric soils or hydrophytic vegetation are present. In addition, wetlands, lakes, 

and ponds are tributaries (even if they lack a bed and banks or ordinary high water 

mark) if they contribute flow, either directly or through another water to a water 

identified in paragraphs (a)(1) through (3) of this section provided that hydric 

soils or hydrophytic vegetation are present. A water that otherwise qualifies as 

a tributary under this definition does not lose its status as a tributary if, for any 

length, there are one or more man-made breaks (such as bridges, culverts, pipes, 

or dams), or one or more natural breaks (such as wetlands at the head of or along 

the run of a stream, debris piles, boulder fields, or a stream that flows 

underground) so long as a bed and banks and an ordinary high water mark can be 

identified upstream of the break. However, these interrupted portions are not 

considered a jurisdictional tributary. A tributary, including wetlands, can be a 

natural, man-altered, or man-made water and includes waters such as rivers, 

streams, lakes, ponds, impoundments, canals, and ditches not excluded in 

paragraph (b)(1), (3), or (4) or (6) of this section. Man-made structures with 

engineered bed, banks, and top of banks that are not created from 

jurisdictional waters or whose construction pre-dates the Clean Water Act 

are not considered a jurisdictional tributary. (p. 5-6)

Agency Response: Paragraph (b) of the final rule excludes many features from 

consideration as waters of the United States, including waste treatment systems 

designed to meet the requirements of the CWA, stormwater control features created 

in dry land and most ditches that are not relocated tributaries or excavated in 

tributaries. Paragraph (b) of the final rule also makes clear that the features 

identified therein “are not waters of the United States even where they otherwise 

meet the terms of paragraphs (a)(1) through (a)(8)” of the rule. Thus, any feature 

excluded under paragraph (b) may not be considered waters of the United States 

under any other provision of the rule. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

104

Arizona Public Service Company (Doc. #15162)

8.119 -The proposed final rule contains a definition of “tributary” is so broad that it overlaps 

and includes other waters that are separately defined as WOTUS, such as impoundments. 

Again, the Agencies fail to include any specifics to clarify the definition... (p. 10)

Agency Response: See summary response for Section 8.1. 

Louisville and Jefferson County Metropolitan Sewer District (Doc. #15413)

8.120 Tributary: The proposed definition of tributary is too broadly defined. In the proposed 

rule a tributary is characterized by a bed, bank and ordinary high water mark which 

contributes flow directly or through other water bodies to a "water of the U.S." The 

proposed rule states that a tributary does not lose its status if there are man-made breaks 

(such as bridges, culverts, pipes, dams) so long as a bed and can be identified up and 

downstream of the break. A tributary can be a natural, man-altered, or man-made and 

includes rivers, streams, lakes, impoundment, canals and ditches (unless excluded). As 

written and applied to the management of stormwater from streets and roads, it is 

arguable that rain gutters and other collection appurtenances are subject to this rule. 

Accordingly, MSD requests clarifications to this definition. (p. 1-2)

Agency Response: See summary response for section 8.1. Paragraph (b) of the 

final rule excludes many features from consideration as waters of the United States, 

including waste treatment systems designed to meet the requirements of the CWA, 

stormwater control features created in dry land and most ditches that are not 

relocated tributaries or excavated in tributaries. As the preamble to the final rule 

notes, curbs and gutters have never been considered waters of the United States.

Orange County Sanitation District, California (Doc. #16335.1)

8.121 [The] overly broad definition of tributary could potentially increase the number of 

manmade conveyances, ditches and conveyance facilities, including those utilized by 

wastewater entities, under federal jurisdiction, and the lack of certainty surrounding the 

rule's definition of a tributary could lead to regulation of previously unregulated waters. 

This broad classification of "tributaries" would be considered jurisdictional regardless of 

perennial, intermittent or ephemeral flow. Even dry washes could be considered 

jurisdictional under the proposed rule. This is significant for a variety of reasons.

One example of the potential impacts of defining what constitutes a "tributary" too 

broadly is the potential discharge from sanitary sewer systems to dry 

creeks/sloughs/washes when no pollutants ever actually reach water. It is entirely unclear 

whether this constitutes a discharge of pollutants to a water of the U.S. Under the broad 

definition of tributary in the proposed rule, it is possible that spills to dry creeks, sloughs, 

or washes would be considered a "discharge" even if there are absolutely no real or 

potential impacts to surface waters of any kind. Similarly, there are circumstances where 

sewer spills occur in a street that drains to a roadside ditch or local creek bed that has no 

flow and is unconnected to a water of the U.S. The responsible party may fully remediate 

the spill and address all real and potential water quality impacts before the spill ever 

reaches a water source. It is difficult to understand how can this kind of circumstance 
Clean Water Rule Response to Comments – Topic 8: Tributaries

105

could be envisioned as a discharge to "waters of the United States" when there is no 

actual water in a dry creek or ditch nor an adverse impact to the environment. (p. 6-7)

Agency Response: See summary response for section 8.1. Paragraph (b) of the 

final rule excludes many features from consideration as waters of the United States, 

including waste treatment systems designed to meet the requirements of the CWA, 

stormwater control features created in dry land and most ditches that are not 

relocated tributaries or excavated in tributaries. 

West Bay Sanitary District, Novato Sanitary District, West County Wastewater District, Union 

Sanitary District and West Valley Sanitation District, California (Doc. #16610)

8.122 NOTE: Although edits are only suggested for the regulatory language most applicable to 

the District, similar changes should be made to each of the proposed sections dealing 

with Waters of the United States (e.g., Parts 112, 116, 117, 230, 232, 300, 302, and 401). 

Alternatively, to simplify the program, a single section setting forth the definition should 

be adopted and utilized for each of the Clean Water Act programs.

...

(5) Tributary. The term tributary means a water physically characterized by the presence 

of a bed and banks and ordinary high water mark, as defined at 33 CFR C.F.R. §328.3(e), 

which contributes perennial flow, either directly or through another water, to a water 

identified in paragraphs (a)(l) through (4) of this definition. In addition, abutting

wetlands, lakes, and ponds are may be tributaries (even if they lack a bed and banks or 

ordinary high water mark) if they contribute perennial flow, either directly or through 

another water to a water identified in paragraphs (a)( 1) through (3) of this definition. A 

water that otherwise qualifies as a tributary under this definition does not lose its status as 

a tributary if, for any length, there are one or more man-made breaks (such as bridges, 

culverts, pipes, or dams), or one or more natural breaks (such as wetlands at the head of 

or along the run of a stream, debris piles, or boulder fields, or a stream that flows 

underground) so long as a bed and banks and an ordinary high water mark can be 

identified upstream of the break. A tributary, including wetlands, can be a natural, manaltered, or man-made water, but does not and includes waters such as rivers, intermittent 

or seasonal streams, channels, lakes, ponds, impoundments, canals and ditches not and 

other water-related features excluded in paragraphs (b)(3) or (4) of theis definition of 

Waters of the United States. 

... (p. 13)

Agency Response: See summary response for Section 8.1. The final rule 

categorically considers tributaries, as defined in the rule that are not otherwise 

excluded under paragraph (b) to be waters of the United States. Section III(C) of 

the preamble and Section VII of the Technical Support Document discuss the 

science supporting the agencies’ determination that waters meeting the definition of 

“tributary” have a significant nexus because they significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas. In response to public comments and in order to increase 

clarity, the final rule does not include wetlands, lakes and ponds as tributaries.
Clean Water Rule Response to Comments – Topic 8: Tributaries

106

Metropolitan Water District of Southern California (Doc. #14637)

8.123 a. The Agencies should evaluate tributaries on a case-by-case basis

...this policy stance means that the jurisdictional scope of the proposed rule is expanded 

from current practice to include features in the bright-line categories that might not be 

found to have a significant nexus to waters of the U.S. on a case-by-case basis. However, 

this same approach was rejected by Justice Kennedy in Rapanos. As stated in Rapanos, 

the Corps deemed water a tributary "if it feeds into a traditional navigable water (or a 

tributary thereof) and possesses an ordinary highwater mark." Rapanos, at 781. Justice 

Kennedy found this standard too broad because it seemed "to leave wide room for 

regulation of drains, ditches, and streams remote from any navigable-in-fact water and 

carrying only minor water volumes toward it." Id. In this way, the breadth of the standard 

"precludes its adoption as the determinative measure of whether adjacent wetlands are 

likely to play an important role in the integrity of an aquatic system comprising navigable 

waters as traditionally understood." Id. Justice Kennedy went on to state that "in many 

cases wetlands adjacent to tributaries covered by this standard might appear little more 

related to navigable-in-fact waters than were the isolated ponds held to fall beyond the 

Act's scope in SWANCC." Rapanos, at 781-82. Accordingly, Metropolitan requests that 

the Agencies continue to evaluate tributaries on a case-by-case basis since under the 

current proposal, many remote and ephemeral tributaries in the arid west, that would not 

significantly affect the (a)(1) through (a)(4) waters, would become jurisdictional, 

resulting in significant additional regulatory burdens on agencies like Metropolitan. (p. 7, 

8)

Agency Response: See summary response for section 8.1. The agencies disagree 

that tributaries should be evaluated on a case-by-case basis. Section III(C) of the 

preamble and VII of the Technical Support Document discuss the science 

supporting the agencies’ determination that waters meeting the definition of 

“tributary” have a significant nexus because they significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas. Section I of the Technical Support Document describes the 

legal basis of the final rule, including its consistency with the statute and case law.

Arizona's Generation & Transmission Cooperatives (Doc. #14901)

8.124 Tributaries are defined in the Proposed Rule as “a water physically characterized by the 

presence of a bed and banks and ordinary high water mark, as defined at 33 CFR 

328.3(e), which contributes flow, either directly or through another water, to a water 

identified in paragraphs (a)(1) through (4).” However, as noted right in the definition of 

“tributary”, only the term “ordinary high water mark” is defined in the regulations. The 

Agencies make no attempt to define “bed and bank” or, more problematically, 

“contributes flow”. (p. 4)

Agency Response: As described in the preamble, for purposes of the final rule, 

“bed and banks” means the substrate and sides of a channel between which flow is 

confined. The banks constitute a break in slope between the edge of the bed and the 

surrounding terrain, and may vary from steep to gradual. Section IV(F) of the 

preamble describes that a water that does not contribute flow to a traditional 
Clean Water Rule Response to Comments – Topic 8: Tributaries

107

navigable water, interstate water or the territorial seas is fundamentally not a 

“tributary” by definition in the final rule.

Utility Water Act Group (Doc. #15016)

8.125 In the Proposed Rule, the Agencies often remark on the function of tributaries as the 

source of inorganic and organic constituents (including particulate organic matter) and 

nutrients, which are transported and utilized by the biota in these reaches. This paradigm 

has parallels to the River Continuum Concept (“RCC”), Vannote et al. (1980),88 one of 

many models that describe the sources of energy in rivers and streams, how this energy is 

utilized downstream, and the trophic structure of the biota. The Proposed Rule states:

Tributaries also influence the chemical composition of downstream waters, through 

the transport and removal of chemical elements and compounds, such as nutrients, 

ions, dissolved and particulate organic matter, pollutants, and contaminants. 

Ecosystem processes in tributaries transform, remove, and transport these substances 

to downstream waters. In turn, these chemical compounds can influence water 

quality, sediment deposition, nutrient availability, and biotic functions in rivers . . . 

Organic carbon, in both dissolved and particulate forms, exported from tributaries is 

consumed by downstream organisms. The organic carbon that is exported 

downstream thus supports biological activity (including metabolism) throughout the 

river network.

79 Fed. Reg. at 22,205 cols. 2-3.

While this generalized hierarchical model – or variations of it – likely is relevant to many 

waterbodies, it is not the only paradigm of an energy source-receptor linkage. 

Autochthonous production and energy inputs from lateral sources occur in streams and 

rivers also. Where instream energy sources are important, the role of energy sources from 

upstream reaches is less. Zale et al. (1989) states:

Headwaters of streams have traditionally been considered heterotrophic (i.e., 

community respiration exceeds production) because seminal studies of stream 

metabolism were conducted in forested regions. Within forests, riparian 

vegetation shades streams and contributes large amounts of allochthonous leaf

litter. . . . However, in prairie ecosystems canopies are open, insolation is high, 

and litter inputs are low. Primary production by benthic algae produces most of 

the organic material. Therefore, headwaters of intermittent streams in the plains 

tend to be autotrophic except perhaps where turbidities are high.

Id. at 5 (emphasis added).

Karr and Dudley (1978)89 paint a similar picture of the sources of energy for mediumsized rivers:

 

88 Robin L. Vannote et al., The River Continuum Concept, 37 Canadian J. Fisheries & Aquatic Sci. 130 (1980).

89 James R. Karr & Daniel R. Dudley, Biological Integrity of a Headwater Stream: Evidence of Degradation, 

Prospects for Recovery, in EPA, EPA-905/9-77-007-D, Environmental Impact of Land Use on Water Quality, Final 

Report on the Black Creek Project (Supplemental Comments) at 3 (Sept. 1978).
Clean Water Rule Response to Comments – Topic 8: Tributaries

108

Functional attributes are markedly different in undisturbed intermediate-sized rivers. 

The stream becomes autotrophic (P/R [production to respiration ratios] > 1) as the 

stream becomes less shaded and algae and vascular plants increase in abundance. 

CPOM [coarse particulate organic matter] inputs are reduced . . . . Incoming 

allochthonous material is primarily FPOM [fine particulate organic matter] from 

headwater areas . . . .

Id. at 8.

The applicability of the RCC model to lower reaches of rivers has been questioned. 

Thoms (2006) states:

The River Continuum Concept . . . was the first of a number of conceptual models 

that have been later criticized . . . because of its inability to evaluate biotic 

assemblages in large rivers and metabolic interactions in ecosystems and its emphasis 

on longitudinal linkages rather than lateral transfers between the channel and 

floodplain.

Id. at 177.

Similarly, Thorp and Delong (1994)90 question the RCC’s relevance to large rivers: 

Previous models of large rivers have ignored or minimized the role of authochthonous 

production. The RCC stated that primary production is often severely limited by 

depth and turbidity, with most production derived from phytoplankton. Field studies 

have shown, however, that benthic algae and aquatic macrophytes are substantial 

sources of organic carbon in some large rivers with constricted channels.

Id. at 307.

Lastly, Thorp et al. (2006) review the various riverine functional models that were 

proposed after the RCC, including the flood pulse concept. The authors themselves 

propose and describe a new lotic functional model termed the riverine ecosystem 

synthesis.

In summary, UWAG believes that the Agencies should have provided more discussion on 

the role of authochthony, a process that is important in some flowing waterbodies. In 

addition, we believe the Agencies were too simplistic in conveying the concept that all 

tributaries conform – more or less – to the principal attributes of the RCC. (p. 126-129)

Agency Response: Section VII of the Technical Support Document discusses the 

science supporting the agencies’ determination that waters meeting the definition of 

“tributary” have a significant nexus because they significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas. See also Compendium 9 on the Scientific Evidence 

Supporting the Rule. In addition, the Science Report on connectivity also addresses 

the important role of autochthonous production especially in prairie streams, see 

Science Report sections 3.4.2 and Case study B.4 Prairie streams. 

 

90 James H. Thorp & Michael D. Delong, The Riverine Productivity Model: An Heuristic View of Carbon Sources 

and Organic Processing in Large River Ecosystems, 70 OIKOS 305 (1994).
Clean Water Rule Response to Comments – Topic 8: Tributaries

109

NiSource Inc. (Doc. #15112)

8.126 The proposed rule categorically determines that tributaries have a significant nexus to 

traditional navigable waters, interstate waters, and the territorial seas. 79 Fed. Reg. at 

22,201. Likewise, waters and wetlands adjacent to tributaries will be automatically 

jurisdictional. Id. at 22,263. Any channelized feature, including ditches and other manmade conveyances, no matter how remote from navigable waters, will be jurisdictional 

tributaries if they exhibit a bed, bank and ordinary high water mark. The proposed rule's 

"tributary" definition, vastly expands the scope of features that are currently regulated as 

tributaries, extending jurisdiction to features like ephemeral drainages and stormwater 

conveyances that have not been and should not be jurisdictional. (p. 4)

Agency Response: See summary response for section 8.1. Paragraph (b) of the 

final rule excludes many features from consideration as waters of the United States, 

including most ditches that are not relocated tributaries or excavated in tributaries 

and stormwater control features created in dry land. Section IV(I) of the preamble 

to the final rule and the summary responses in Compendium 7 of this RTC, 

“Features and Waters Not Jurisdictional,” provide a broad discussion of the final 

rule’s exclusions. Section 6.2 of this RTC, “Excluded Ditches,” provides a more 

focused discussion on the revisions and clarifications of the ditch exclusions. 

Northern Colorado Water Conservancy District, Berthoud, Colorado (Doc. #15114)

8.127 The proposed definition of a jurisdictional "tributary" would significantly expand the 

scope of CWA jurisdiction. 'Tributary" would be defined as any water that is physically 

characterized by the presence of a bed and bank and ordinary high water mark and which 

contributes flow (directly or indirectly) to other waters that eventually flow into a 

traditional navigable water or interstate water.91 We have the following concerns with 

this approach:

A.The treatment of all "tributaries" as jurisdictional-by-rule would inappropriately lump 

together large rivers and perennial streams with minor, often dry ephemeral and 

intermittent drainages. Under the proposed rule, there would be no minimum frequency, 

duration or volume of flow required-perennial, intermittent, and ephemeral streams 

would all automatically qualify as jurisdictional tributaries.92 This fails to recognize that 

there are differences among various types of drainages and even within individual 

drainages in terms of their associated resources and potential for affecting the chemical, 

physical or biological integrity of downstream waters. This is especially true for drainage 

areas that are dry during all or part of most years. It is important to preserve a process for 

individually determining the jurisdictional status of ephemeral and intermittent drainages 

that can consider and accommodate the variability between drainage types and how they 

differ regionally. 

B. The assertion of jurisdiction over relatively remote intermittent and ephemeral 

drainages is not supported by Justice Scalia's plurality opinion in Rapanos v. United 

 

91 Definition of "Waters of the United States" under the Clean Water Act, 79 Fed. Reg. at 22 199 (proposed 

amendment to 33 C.F.R. 328.3(a) (5)).

92 Definition of "Waters of the United State s" under the Clean Water Act, 79 Fed. Reg. at 22202.
Clean Water Rule Response to Comments – Topic 8: Tributaries

110

States.

93 As described in that opinion, CWA jurisdiction would extend only to "those 

relatively permanent, standing or continuously flowing bodies of water ‘forming 

geographic features’ that are described in ordinary parlance as ‘streams [.] .. . oceans, 

rivers, [and] lakes.’”94 The Rapanos plurality stated that CWA jurisdiction does "not 

include channels through which water flows only intermittently or ephemerally, or 

channels that periodically provide drainage for rainfall.”95 Even Justice Kennedy's 

concurring opinion in Rapanos, upon which this rulemaking effort relies most heavily, 

does not support a broad regulation of tributaries in the absence of more specific 

criteria.96

...

Accordingly, if the agencies proceed to establish a jurisdictional-by-rule category for 

"tributaries," that category should be restricted to features that contribute flow to a 

traditional navigable water On a relatively permanent basis, consistent with the plurality 

opinion in Rapanos. The agencies should evaluate intermittent and ephemeral water 

bodies on a case-by-case basis to determine whether to treat a given water as 

jurisdictional, consistent with current practice. These case-by-case evaluations could be 

facilitated through further guidance on factors (such as frequency, duration and volume 

of flow) indicative of the varying strengths of connections between features and the 

jurisdictional waters into which they convey flow. Other factors could include the 

strength (or lack) of the ordinary high water mark and bed/bank indicators, the presence 

and length of breaks in jurisdictional features, flow loss from infiltration and 

evaporation, and distance to a traditional navigable water. This type of approach would 

be consistent with Justice Kennedy's concurring opinion, which suggested the need for 

"more specific" criteria defining jurisdictional tributaries. (p. 4-5)

Agency Response: See summary response for Section 8.1. The final rule 

categorically considers tributaries, as defined in the rule that are not otherwise 

excluded under paragraph (b) to be waters of the United States. Section III(C) of 

the preamble and Section VII of the Technical Support Document discuss the 

science supporting the agencies’ determination that waters meeting the definition of 

“tributary” have a significant nexus because they significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 

 

93 Rapanos v. United States, 547 U.S. 715 (2006).

94 Id. at 739.

95 Id.

96 Justice Kennedy' s opinion in Rapanos concurred in the judgment but not in the plurality opinion's rationale 

regarding Congress's limits on the reach of CWA jurisdiction. Justice Kennedy's concurring opinion noted that the

agencies' existing standard for tributaries (which relies on the presence of a connection to a traditional navigable

water and certain physical characteristics indicating an ordinary high water mark) was too expansive to provide the

basis for a jurisdictional determination regarding adjacent wetlands because it seemed to " leave wide room for 

regulation of drains, ditches, and streams remote from any navigable-ill-fact water and carrying only minor water 

volumes toward it." Rapanos, 547 U.S. at 781. He suggested that the agencies could " identify categories of

tributaries that, due to their volume of flow (either annually or on average), their proximity to navigable waters, or 

other relevant considerations, are significant enough that wetlands adjacent to them are likely, in the majority of 

cases, to perform important functions for an aquatic sys tem incorporating navigable waters." Id.
Clean Water Rule Response to Comments – Topic 8: Tributaries

111

and the territorial seas. Section I of the Technical Support Document describes the 

legal basis of the final rule, including its consistency with the statute and case law.

Nebraska Public Power District (Doc. #15126)

8.128 The Preamble uses the word "convey" when discussing the characteristics of tributaries: 

waters are tributaries when they "convey water to traditionally navigable waters, 

interstate waters, and territorial seas." But if most bodies of water eventually convey 

water somewhere else, would not most of them meet the definition of tributary under the 

proposed rule?

NPPD does not agree with the way tributaries are defined in the proposed rule. Many 

areas that were non-jurisdictional waters become jurisdictional. The statement that the 

jurisdiction in the proposed rule is narrower than that under the existing regulations is 

simply not true. For this reason, NPPD recommends the elimination of the proposed 

provision. (p. 7)

Agency Response: See summary response for Section 8.1. The final rule 

categorically considers tributaries, as defined in the rule that are not otherwise 

excluded under paragraph (b) to be waters of the United States. Section III(C) of 

the preamble and Section VII of the Technical Support Document discuss the 

science supporting the agencies’ determination that waters meeting the definition of 

“tributary” have a significant nexus because they significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters,

and the territorial seas. Section I of the Technical Support Document describes the 

legal basis of the final rule, including its consistency with the statute and case law.

Lower Colorado River Authority (Doc. #16332)

8.129 The Agencies’ proposed definition for “tributary” is overly broad and lacks sufficient 

clarity. As noted above, the Agencies’ definition fails to give adequate consideration to 

the plurality opinion in Rapanos and the holding in SWANCC, and it relies almost 

exclusively on legally irrelevant portions of Justice Kennedy’s concurring opinion in 

Rapanos. Moreover, even if the Agencies’ definition for “tributary” were consistent with 

the law, it is ambiguous, leaving the regulated public to guess as to which water bodies 

the Agencies intend to regulate. The Agencies propose to identify a “tributary” based on 

the presence of a bed, bank, OHWM, and any minimal amount of flow that eventually 

reaches navigable waters. As Justice Kennedy stated in his Rapanos opinion, however, 

these terms are not sufficiently detailed to provide appropriate limits on the Agencies’ 

exercise of jurisdiction.97 (p. 15)

Agency Response: See summary response for Section 8.1. The final rule 

categorically considers tributaries, as defined in the rule that are not otherwise 

excluded under paragraph (b) to be waters of the United States. Section III(C) of 

the preamble and Section VII of the Technical Support Document discuss the 

science supporting the agencies’ determination that waters meeting the definition of 

“tributary” have a significant nexus because they significantly affect the chemical, 

 

97 Rapanos, 547 U.S. at 734.
Clean Water Rule Response to Comments – Topic 8: Tributaries

112

physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas. Section I of the Technical Support Document describes the 

legal basis of the final rule, including its consistency with the statute and case law.

Tri-State Generation and Transmission Association, Inc. (Doc. #16392)

8.130 Reliance on the ordinary high water mark concept, which is known to be problematic in 

arid/desert regions for intermittent and ephemeral streams,98 and categorizing all 

tributaries as jurisdictional by rule sets up a situation where individual landowners will 

have little ability to counter assertions of jurisdiction over a particular ephemeral 

tributary when absence of a significant nexus is likely. Accordingly, TriState requests 

that the final rule establish an off-ramp for intermittent and ephemeral tributaries and 

request the definition of tributaries in the final rule include a rebuttable presumption of 

jurisdiction for non-perennial tributaries rather than strict jurisdiction by rule. 

Alternatively, the definition of tributaries could be modified to specify perennially 

flowing tributaries and intermittent and ephemeral streams could be incorporated into the 

definition of other waters. This would address the lack of scientific basis for the 

jurisdictional by rule approach noted above by several SAB panelists while allowing 

regulated entities the option of either rapidly accepting a tributary as jurisdictional (e.g., 

similar to the present practice under Preliminary JDs), or providing a site specific 

significant nexus analysis to the Agencies for review. (p. 12-13)

Agency Response: See summary response for Section 8.1. The final rule 

categorically considers tributaries, as defined in the rule that are not otherwise 

excluded under paragraph (b) to be waters of the United States. Section III(C) of 

the preamble and Section VII of the Technical Support Document discuss the 

science supporting the agencies’ determination that waters meeting the definition of 

“tributary” have a significant nexus because they significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas. See also Section 9 “Scientific Evidence Supporting the Rule” 

of the Response to Comments. See summary response for Section 8.4 below, 

“Tributaries distinguished from non-jurisdictional gullies, rill, non-wetland swales.”

Texas Water Development Board (Doc. #16563)

8.131 The proposed rule uses the existence of an ordinary high water mark as a minimal 

starting point for determining if a tributary has defined bed and banks and is potentially 

jurisdictional. This factor might be useful as a first step in eliminating waterways that are 

not jurisdictional. But the rule then goes on to suggest that tributaries with defined bed 

and banks and contributes flow, either directly or indirectly, would be expected to be 

jurisdictional. This presumption would apparently be applicable to intermittent and 

ephemeral streams as well.

 

98 Engineer Research & Development Center, U.S. Army Corps of Engineers, "A Guide to Ordinary High Water 

Mark (OHWM) Delineation for Non-Perennial Streams in the Western Mountains, Valleys, and Coast Region of the 

United States," at 1 (August 2014).
Clean Water Rule Response to Comments – Topic 8: Tributaries

113

All tributary streams, including perennial, intermittent, and ephemeral streams, are 

physically, chemically, and biologically connected to downstream rivers or open waters 

via channels and associated alluvial deposits. Headwater streams (primarily intermittent 

and ephemeral) are the most abundant stream type in most river networks and supply 

most of the water in rivers, to the greatest extent in arid areas. Headwater streams are the 

source of approximately 60% of the total mean annual flow to all northeastern U.S. 

streams and rivers. Based on the high level of in response to comments to provide 

increased clarity. The agencies believe that the connectivity, the EPA and Corps could 

claim all such waters as categorically waters of the U.S. 

...

Specific Recommendations

...

3. EPA and the Corps should consider only relatively permanent tributaries as 

jurisdictional and provide objective steps to determine connectivity based on the plurality 

opinion in Rapanos. (p. 6, 7)

Agency Response: See summary response for Section 8.1. The final rule 

categorically considers tributaries, as defined in the rule that are not otherwise 

excluded under paragraph (b) to be waters of the United States. Section III(C) of 

the preamble and Section VII of the Technical Support Document discuss the 

science supporting the agencies’ determination that waters meeting the definition of 

“tributary” have a significant nexus because they significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas. Section I of the Technical Support Document describes the 

legal basis of the final rule, including its consistency with the statute and case law.

Northern California Association (Doc. #17444)

8.132 The agencies should provide assurances in a final rule that the definition of “tributary” 

will be limited to those with “bed and banks with an ordinary high water mark” that have 

formed over several years, and that would not include temporary accumulations of 

sediment or hydraulic activity resulting from specific isolated precipitation or runoff 

events. Definitions must be fleshed out for the terms ordinary high water mark, bed and 

banks, and other subjective terminology used in the proposed rule that can and will cause 

uncertainty in the implementation of a final rule.

...

Jurisdictional tributaries should meet a new "bright line" test related to size of bed and 

banks, amount of flow, or distance from the jurisdictional navigable water in order to be 

considered a "water of the U.S.", establishing a limit on just how small, or dry, or how far 

upstream the CWA would apply from the jurisdictional navigable water. Wetlands 

should not be considered "tributaries" in the final rule, as they should have to meet 

"adjacency" or "significant nexus" tests associated with "adjacent" or "other waters" to be 

considered "waters of the U.S." (p. 6-7)

Agency Response: See summary response for section 8.1. The term “ordinary 

high water mark” has been defined in Corps regulations since 1986, and used by 
Clean Water Rule Response to Comments – Topic 8: Tributaries

114

Corps Districts nationwide to determine the lateral limits of jurisdiction over nontidal water bodies for the CWA section 404 permitting program. As described in 

the preamble, for purposes of the rule, “bed and banks” means the substrate and 

sides of a channel between which flow is confined. The banks constitute a break in 

slope between the edge of the bed and the surrounding terrain, and may vary from 

steep to gradual. In response to public comments and in order to increase clarity, 

the final rule does not include wetlands, lakes and ponds as tributaries.

Cloud Peak Energy (Doc. #18010) 

8.133 The expanded definition of WOTUS would include channels that flow infrequently such 

as ephemeral and intermittent drainages, non-navigable ditches and isolated waters. 

Currently there are rules in place to protect these non-navigable waters such as the 

Section 402 National Pollutant Discharge Elimination System (NPDES), Section 401 

state water quality certification process, Section 311 oil spill program, and Section 303 

water quality standards and total maximum daily load programs. The proposed rule does 

not provide any documentation to show that the existing rules do not adequately protect 

these non-navigable waters. The rule’s expansion of jurisdictional waters is unwarranted 

as there are regulations in place that protect these waters. (p. 2) 

Agency Response: See summary response for section 8.1. Paragraph (b) of the 

final rule excludes many features from consideration as waters of the United States, 

including most ditches that are not relocated tributaries or excavated in tributaries 

and erosional features that do not meet the definition of tributary. Section IV(I) of 

the preamble to the final rule and the summary responses in Compendium 7 of this 

RTC, “Features and Waters Not Jurisdictional,” provide a broad discussion of the 

final rule’s exclusions. See summary response for section 6.2, “Excluded Ditches” in 

this RTC and summary response for section 8.4 below. All provisions of the CWA 

referenced in the comment above utilize the same definition of “waters of the United 

States,” so those streams were and will continue to be protected because they are 

“waters of the U.S.” In this final rule, the agencies are responding to requests from 

across the country to make the process of identifying waters protected under the 

CWA easier to understand, more predictable, and more consistent with the law and 

peer-reviewed science.

Tucson Electric Power Company, UNS Energy Corporation (Doc. #19561)

8.134 We believe there needs to be a defined limit in the definition of tributary such as exact 

wash width, flow rate, distance from a TNW, and set by the rule that identifies with 

certainty the extent of CWA jurisdiction over [ephemeral drainages] local, regional and 

state waters. The agencies continue to profess that the proposed rule will not expand 

federal jurisdiction, but we believe otherwise. 

Recommendations:

To reduce any uncertainty in identifying the limit of WUS subject to CWA jurisdiction, 

the final rule should include the following with regards to the definition of "tributary":

The agencies should provide assurances in the final rule that the definition of "tributary" 

will be limited to those with "bed and banks with an ordinary high water mark" that have 
Clean Water Rule Response to Comments – Topic 8: Tributaries

115

formed from ordinary precipitation events in the region, and that would not include 

temporary accumulations of sediment, debris or other indicators of extreme hydraulic 

activity resulting from specific isolated or peak-flow precipitation or runoff events.

Definitions for the terms "ordinary high water mark", "bed and banks", and other 

subjective terminology used in the proposed rule that can and will cause uncertainty in 

the implementation of a final rule should be more clearly and precisely described in the 

rule.

The final rule should establish a "bright line" or set of regionally-specific metrics, 

establishing a limit (Le. specifically report indicates the size or width of bed and banks, 

amount of flow, or distance upstream) for a "tributary" to be considered WUS. (p. 5)that 

numerous features which contribute to the physical, chemical or biological integrity of 

downstream waters do not necessarily have hydric soils/hydrophytic vegetation within 

the channel. 

Agency Response: See summary response for section 8.1. The term “ordinary 

high water mark” has been defined in Corps regulations since 1986, and used by 

Corps Districts nationwide to determine the lateral limits of jurisdiction over nontidal water bodies for the CWA section 404 permitting program. As described in 

the preamble, for purposes of the rule, “bed and banks” means the substrate and 

sides of a channel between which flow is confined. The banks constitute a break in 

slope between the edge of the bed and the surrounding terrain, and may vary from 

steep to gradual.

Chesapeake Bay Foundation (Doc. #14620)

8.135 i. CBF supports the agencies’ finding that tributaries have a significant nexus with waters 

defined in (s) 1-3 of the proposed definition. This finding is consistent with our 

experience in the Chesapeake Bay Watershed where there is a clear chemical, physical, 

and biological interrelationship between a water, the tributary network, shallow 

groundwater aquifers and traditional navigable waters, interstate waters, and the 

territorial seas. This interrelationship is central to our efforts to reduce loads of nitrogen, 

phosphorus and sediment under the Chesapeake Bay TMDL and associated state 

Watershed Implementation Plans (WIP). For example, a U.S. Geological Survey 

investigation into the possible causes of the 1997 Pfisteria outbreak which killed 

thousands of fish and sickened residents in the Pocomoke River, MD linked the 

contribution of nutrient sources from both surface and shallow groundwater as a 

contributing factor.99 (p. 5)

Agency Response: The final rule categorically considers tributaries, as defined in 

the rule that are not otherwise excluded under paragraph (b) to be waters of the 

United States. 

 

99 Fish Health, Fungal Infections, and Pfiesteria: The Role of the U.S. Geological Survey, U.S. Geological Survey 

Fact Sheet 114-98 , By Vicki Blazer, Scott Phillips, and Edward Pendleton
Clean Water Rule Response to Comments – Topic 8: Tributaries

116

National Wildlife Federation (Doc. #15020)

8.136 We support the agencies’ proposed rule that “all waters that meet the proposed definition 

of tributary are “waters of the United States” by rule, unless excluded under section (b), 

because tributaries and the ecological functions they provide, alone or in combination 

with other tributaries in the watershed, significantly affect the chemical, physical, and 

biological integrity of traditional navigable waters, interstate waters, and territorial seas.” 

79 Fed. Reg. 22201.100 (p. 30)

Agency Response: The final rule categorically considers tributaries, as defined in 

the rule that are not otherwise excluded under paragraph (b) to be waters of the 

United States. 

8.137 The proposed rule is strongly supported by the draft Connectivity Report, which 

thoroughly documents and supports its conclusion that “[a]ll tributary streams, including 

perennial, intermittent, and ephemeral streams, are physically, chemically, and 

biologically connected to downstream rivers via channels and associated alluvial deposits 

where water and other materials are concentrated, mixed, transformed, and transported.” 

Connectivity Report at 1-3. The report includes a thorough examination of the literature 

with respect to ephemeral stream connectivity, particularly in the arid southwest.

This conclusion with regard to all tributary streams is strongly supported by the SAB 

Connectivity Peer Review Report as well,101 and is fully consistent with and relevant to 

Justice Kennedy’s significant nexus test. Justice Kennedy suggests the current definition 

of tributary “may well provide a reasonable measure of whether specific minor tributaries 

bear a sufficient nexus with other regulated waters to constitute ‘navigable waters’ under 

the Act.” Rapanos at 2249.

We urge the agencies to swiftly finalize this rule, clearly restoring longstanding 

protections for all tributary waters. Our research, as well as comments submitted by 

Corps officials, indicate that many lower order intermittent and ephemeral streams were 

left unprotected following issuance of the Guidance in 2007 and 2008, likely because of 

the inability to aggregate streams impacts. A Corps employee has commented that:

[O]ur district has determined that we cannot defensibly say that most individual 

first order/ephemeral stream reaches have a significant effect on a TNW. EPA and 

the Sierra Club argue that those first order/ephemeral headwater streams should 

be regulated because cumulatively they greatly effect [sic] the integrity of the 

 

100 We remind the agencies that Justice Kennedy does not assert that categorical regulation of tributaries is no longer 

permissible, or that a case-by-case determination of a “significant nexus” to TNWs or IWs is required to regulate 

any tributary. Justice Kennedy’s opinion limited his basis for remand to the lower court to the question of “whether 

the specific wetlands at issue possess a significant nexus with navigable waters.” 126 S. Ct. 2252. This contrasts 

with the plurality’s broader basis for remand to determine “whether the ditches and drains near wetlands are

‘waters,’” and “whether the wetlands in question” are also jurisdictional. Id. at 2235. This contrast is further 

indication Justice Kennedy may not require a case-by-case significant nexus determination for tributaries. It is only 

in regards to wetlands adjacent to minor tributaries that Justice Kennedy refuses to allow categorical assertion of 

jurisdiction under the current regulations. Id. at 2249 (“Absent more specific regulations, . . . the Corps must 

establish a significant nexus on a case-by-case basis when it seeks to regulate wetlands based on adjacency to nonnavigable tributaries.”).

101 See discussion supra at 22.
Clean Water Rule Response to Comments – Topic 8: Tributaries

117

TNWs. We do not argue that. However, the Supreme Court ruling and the 

Rapanos guidance did not say to look at them cumulatively. Not until several first 

or second order streams merge into a higher order stream can we defensibly argue 

that a stream has a significant effect.102

We have also found several instances where streams, some quite sizable, are not being 

protected.103 Some of these streams are being subjected to channelization and other 

projects that can have significant and harmful water quality and habitat implications. And 

failing to protect these streams leaves them vulnerable to other pollution, like the 

dumping of industrial and other waste that poses clear threats to downstream water 

quality, not to mention the tributary itself.

We urge the agencies to finalize this rule, confirming that any water that meets the 

definition of tributary (and is not excluded under section (b) of the proposed rule) has a 

significant nexus to a traditionally navigable water, interstate water, or territorial sea such 

that it is a ‘waters of the United States’ without the need for a separate, case-specific 

significant nexus analysis. Id. (p. 31-32)

Agency Response: See summary response for Section 8.1. The final rule 

categorically considers tributaries, as defined in the rule that are not otherwise 

excluded under paragraph (b) to be waters of the United States. Section III(C) of 

the preamble and Section VII of the Technical Support Document discuss the 

science supporting the agencies’ determination that waters meeting the definition of 

“tributary” have a significant nexus because they significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas. See also Section 9 “Scientific Evidence Supporting the 

Rule” of the Response to Comments.

8.138 A. The agencies’ definition of tributary is consistent with existing law and science, 

and does not expand Clean Water Act jurisdiction.

The agencies’ definition of “tributary” includes several clarifying elements, all of which 

are consistent with existing law, science, and past practice. See 33 CFR 328.3 (c)(5); 79 

Fed. Reg. 22201-06, 22263. Fundamentally, the proposed rule defines “tributary” as:

[A] water physically characterized by the presence of a bed and banks and 

ordinary high water mark, as defined at 33 CFR 328.3(e), which contributes flow, 

either directly or through another water, to a water identified in paragraphs (a)(1) 

 

102 Email from Cody Wheeler, codywheeler68@sbcglobal.net, Corps Employee, to OW-Docket@EPA (Nov. 16, 

2007).

103 See, e.g., Approved Jurisdictional Determination Form, U.S. Army Corps of Engineers, File NWK-2007-01586-1 

(Aug. 17, 2007) (no jurisdiction found for second order stream with 384 acres of drainage, estimated to be 8,000 

linear feet in length with 626 acre watershed); Approved Jurisdictional Determination Form, U.S. Army Corps of 

Engineers, File NWK-2007-01586-2, (Aug. 17, 2007) (no jurisdiction found for a first order stream with 115 acres 

of drainage and a watershed size that is also 115 acres. It is estimated to be 3,800 linear feet in length); Approved

Jurisdictional Determination Form, U.S. Army Corps of Engineers, File NWO-2007-2195-DEN (Nov. 1, 2007) 

(ephemeral stream flowing into a reservoir used for water supply not jurisdictional).
Clean Water Rule Response to Comments – Topic 8: Tributaries

118

through (4) [traditionally navigable waters, interstate waters, territorial seas, and 

impoundments of these waters as well as tributaries]. Id.

Importantly, and consistent with the science, law, and past practice, the agencies’ 

tributary definition clarifies specific tributary circumstances where the OHWM is not 

determinative of tributary status: 1) “wetlands, lakes, and ponds are tributaries (even if 

they lack a bed and banks or ordinary high water mark) if they contribute flow, either 

directly or through another waters to a water identified in paragraphs (a)(1) through (3);” 

and 2) a water “does not lose its status as a tributary if, for any length, there are one or 

more man-made breaks ..., or one or more natural breaks ... so long as a bed and banks 

and an ordinary high water mark can be identified upstream of the break.” While the

OHWM typically provides a strong indicator of relatively frequent flow for linear stream 

channels, it is not a reliable indicator of flow for non-linear water bodies such as 

wetlands, lakes, and ponds which none the less do contribute flow downgradient. See 79 

Fed. Reg. at 22203; 22235.

Also consistent with the Act, the legal precedent, and the underlying connectivity science 

is the definition’s clarification that a tributary, including a wetland, can be “natural, manaltered, or man-made” and includes “rivers, streams, lakes, ponds, impoundments, canals, 

and ditches not excluded in paragraph (b)(3) or (4) of this section.” Id. There is 

significant case law that supports the regulation of man-made and man-altered waters as 

tributaries.104 (p. 32)

Agency Response: See summary response for Section 8.1. In response to public 

comments and in order to increase clarity, the final rule does not include wetlands, 

lakes and ponds as tributaries. See summary response for section 8.2 below. These 

waters may still be considered “waters of the United States” under other provisions 

of the final rule.

Center for Biological Diversity, Center for Food Safety, and Turtle Island Restoration Network 

(Doc. #15233)

8.139 While tributaries, like other water bodies, vary in their degree of their influence on 

downstream waters, including traditionally jurisdictional downstream waters, overall, 

tributaries play a highly significant role in the chemical, physical, and biological 

 

104 See, e.g, United States v. Moses, 496 F.3d 984 (9th Cir. 2007), cert denied, 554 U.S. 918 (2008) (stream impacted 

by man-made diversion jurisdictional); Vierstra, supra, at *5 (“The fact that the Low Line Canal is man-made is of 

no moment. The canal is part of a tributary system connecting navigable waters upstream and downstream for six to 

eight months of the year. Its man-made nature makes it no less capable of carrying pollution to navigable and 

interstate waters. Moreover, there are many water-ways in the Intermountain West that have been re-routed, recountered, and re-channeled in an effort to control, store, and use the limited water we have. Excluding these waterways from the jurisdiction of the CWA when they might otherwise constitute tributaries of navigable waters makes 

little practical sense.”); see also, United States v. Gerke Excavating, Inc., 412 F.3d 804, 805-06 (7th Cir. 2005), 

vacated and remanded 548 U.S. 901 (2006) (ordering further consideration in light of Rapanos), remanded 464 F.3d 

723, 725 (7th Cir. 2006) (remanding to district court for further fact finding to determine whether particular 

wetlands were jurisdictional “waters of the United States” under Justice Kennedy’s significant nexus test). (Finding 

that, “A stream can be a tributary; why not a ditch? A ditch can carry as much water as a stream, or more; many 

streams are tiny. It wouldn’t make much sense to interpret the [Corps’] regulation[s] as distinguishing between a 

stream and its man-made counterpart.”).
Clean Water Rule Response to Comments – Topic 8: Tributaries

119

character of their downstream waters. We therefore concur that tributaries, “as a category 

. . . play a critical role in the integrity of aquatic systems comprising traditional navigable 

waters and interstate waters, and therefore are ‘’waters of the United States’ within the 

meaning of the Clean Water Act.” 79 Fed. Reg. 22260.

However, the conservation groups regard the proposed rule’s definition of “tributary” to 

be confusing and unwarrantedly cramped, and thus insufficiently protective of tributary 

water bodies and the downstream waters they affect. In particular, we are concerned that 

the overly narrow definitions may not adequately protect headwaters, as well as seasonal 

and ephemeral tributaries. 

The proposed definition of tributary requires such a water body to be “physically 

characterized by the presence of a bed and banks and ordinary high water mark . . .which 

contributes flow, either directly or through another water” to a traditionally jurisdictional 

water body. 79 Fed. Reg. 22268. Your proposed definition then proceeds to hedge as to 

this requirement for an ordinary high water mark (hereinafter, “OHWM”) – reflecting 

your uncertainty as to this requirement – by stating that “[a] water that otherwise qualifies 

as a tributary . . . does not lose its status as a tributary if, for any length, there are one or 

more man-made breaks . . . or one or more natural breaks. . . so long as a bed and banks 

and an [OHWM] can be identified upstream of the break.”

In fact, your requirement for an OHWM, even an intermittent OHWM, would work to 

exclude from the definition and, thus, the protection accorded water bodies with tributary 

“status,” certain streams whose flow, either alone or in the aggregate, would have an 

important effect on the physical, chemical or biological integrity of traditionally 

jurisdictional water bodies. As the EPA’s SAB has observed,“[t]he absence of OHWM is 

relatively common in ephemeral streams within arid and semi-arid environments or low 

gradient landscapes.” SAB Sept. 2, at 5. With respect to streams in areas of limited 

precipitation, an EPA expert report previously concluded:

When functioning properly, arid and semi-arid region streams provide many of

the same services as perennial streams that affect water quality and ecosystem

health. These services include landscape hydrologic connections; surface and

subsurface water storage and exchange; ground-water recharge and discharge;

sediment transport, storage, and deposition; flood plain development; nutrient

cycling; wildlife habitat including movement and migration corridors; support for

vegetation communities that help stabilize stream banks and provide wildlife

services; water supply and water quality filtering or cleansing; and stream energy

dissipation associated with high-water flows that reduces erosion and improves

water quality (USFWS, 1993; BLM, 1998). In addition, riparian areas associated

with ephemeral and intermittent streams help mitigate and control water pollution

by removing pollutants and sediment from surface runoff (Sonoran Institute,

2007). Thus, these streams play a significant role in the physical, biological, and

chemical integrity of an ecosystem and must be afforded the same importance as

other wetter systems in the U.S.

EPA, The Ecological and Hydrological Significance of Ephemeral and Intermittent 

Streams in the Arid and Semi-arid American Southwest (2008), at 76.
Clean Water Rule Response to Comments – Topic 8: Tributaries

120

As noted, a large number of ephemeral and intermittent streams may fail to generate an 

OHWM, yet still contribute substantial flows and ecosystem functions, either individually 

or collectively. Indeed, there are many such streams. Analysis presented by EPA 

establishes that intermittent and ephemeral streams comprise 59 percent of total stream 

length in the lower 49 states, and that one third of the U.S. population gets “some or all of 

their drinking water from public drinking water systems that rely in part on headwater, 

seasonal, or rain-dependent streams.” See “Map of seasonal and rain-dependent streams,” 

and “Map of county-by-county drinking water data,” viewed Sept. 26, 2014 at 

http://water.epa.gov/lawsregs/guidance/wetlands/CWAwaters.cfm.

The operative question is whether the water body contributes flow or otherwise 

influences the functioning of other waters, as evidenced by your inclusion of wetlands, 

lakes and ponds that contribute flow irrespective of whether they are characterized by an 

OHWM (or, for that matter, a discernible bed or a bank). 79 Fed. Reg. 22268.105 Rather 

than relying on a morphological test, the conservation groups urge you to make the 

contribution of flows or their influence on downstream waters the center of the definition, 

while retaining the bed and bank and OWHM tests as operationally useful. Second, we 

also urge you to provide for those streams which are functionally important individually 

or collectively, but do not have they typical bed and bank or OWHM morphology. 

Accordingly, the conservation groups urge that you amend your definition of tributary as 

follows:

Tributary. The term tributary means a water that contributes flow to or influences 

the physical, chemical or biological characteristics of a water identified in 

paragraphs (a)(1) through (4) of this definition, either directly or through another 

water and either individually or in combination with other similarly situated 

waters in the region. A water contributes flow or influences the physical, 

chemical, or biological characteristics of a receiving water when the water is 

physically characterized by the presence of a bed and banks, physically 

characterized by an ordinary high water mark as defined at 33 CFR 328.3(e), or 

characterized by other evidence or indicators of flow, which contributes flow, 

either directly or through another water, to a water identified in paragraphs (a)(1) 

through (4) of this definition.

79 Fed. Reg. at 22268 (proposed 40 CFR 122.2 (c)(6)). This definition has three 

beneficial characteristics. First, it retains the key scientific principles that justify the 

inclusion of tributaries at its core such that in cases of disputes, it is the functions of the 

waterway that ultimately determine its status. Second, the two-stage definition allows 

field offices to rely on the important bed and bank and OWHM tests for the many waters 

where those approaches are appropriate. Third, the final prong allows the EPA and Army 

Corps of Engineers the flexibility to rely on other evidence where necessary to account 

for waters where the OWHM and bed and bank tests are not appropriate.

 

105 SAB Sept. 17 at 2 also advises that tributaries “are not typically defined to include lentic systems (e.g., lakes, 

ponds, wetlands). Thus, the EPA may want to consider whether flow-through lentic systems should be included as 

adjacent waters and wetlands, rather than as tributaries.” The conservation groups agree with the SAB’s observation 

about the typical definition, but reserve comment at this time on whether your special definition is unmanageable.
Clean Water Rule Response to Comments – Topic 8: Tributaries

121

As a companion to defining “tributary” in functional, rather than morphological, terms, 

we urge you to remove the exclusion of “gullies” and “rills” throughout the rule. As you 

note at 79 Fed. Reg. 22219, the definition of tributary cannot easily be reconciled with 

this exclusion, precisely because there is not a functional principle suggesting that gullies 

and rills function differently from other waterways of similar size and position. As 

described above, particularly in arid, semi-arid, and seasonal regions, deeply incised and 

erosional features contribute considerable flows and exert critical functional influence on 

downstream waters, and are often permanent features. In addition, in many contexts, 

human activities that remove vegetation and accelerate in-stream velocities, such as 

overgrazing or development, can convert existing streams into deeply incised “gullies.” 

These human activities can also divert surface or subsurface flows into defined and 

permanent streams that contribute important flows and sediments to downstream waters 

on an ongoing and permanent basis. As noted in section 3.3.6 of the SAB report, although 

these impacts may be recent in a dynamic and altered landscape, this does not mean that 

these waters are not functionally important and connected to down-gradient waters.

Simply because such streams are recent in origin does not remove their functional 

importance. In these contexts, morphological features such as deep incision, downcutting and head-cutting do not provide any scientific basis for excluding such 

functionally important streams from regulation. Indeed, the EPA’s difficulty in 

differentiating between excluded “gullies” and “rills” on the one hand, and categorical 

jurisdictional ephemeral tributaries in arid regions on the other, points clearly to the fact 

that this exclusion is poorly grounded in terms of the hydrological function of such 

features. The discussion of the exclusion appears to rest on the age of features and their 

origin as erosional features on steep and erodible soils, yet neither of those characteristics 

have direct bearing on the hydrological connection to other waters. As noted above, 

gullies and rills may be permanent in some landscapes and in others may result from 

damage to existing waterways. In neither case is there a scientific basis for their 

exclusion. Therefore, we recommend that the exclusions of gullies and rills be removed 

from the rule entirely rather than seeking a contrived and cramped distinction that does 

not exist in real world terms. (p. 3-5)

Agency Response: See summary response for Section 8.1. The agencies’ 

interpretive task in this rule – determining which waters have a “significant nexus” 

– requires the integration of the science with policy judgment and legal 

interpretation. The final rule categorically considers tributaries, as defined in the 

rule that are not otherwise excluded under paragraph (b) to be waters of the United 

States. Section III(C) of the preamble and Section VII of the Technical Support 

Document discuss the science supporting the agencies’ determination that waters 

meeting the definition of “tributary” have a significant nexus because they 

significantly affect the chemical, physical, and biological integrity of traditional 

navigable waters, interstate waters, and the territorial seas. See also Section 9 

“Scientific Evidence Supporting the Rule” of the Response to Comments. In 

response to public comments and in order to increase clarity, the final rule does not 

include wetlands, lakes and ponds as tributaries. See summary response for section 

8.2 below. These waters may still be considered “waters of the United States” under 

other provisions of the final rule.
Clean Water Rule Response to Comments – Topic 8: Tributaries

122

American Rivers (Doc. #15372)

8.140 E. Effects of Ambiguous WOTUS Definition...

3. Impacts to Drinking Water Supply

Approximately 286 million Americans get their water from a public water system 

monitored and regulated by the EPA.106 Of those, 117 million get their drinking water 

from public systems that rely on seasonal, intermittent, and ephemeral headwater 

streams.107 Restoring protections to these small streams and surrounding wetlands under 

the proposed rule is critical to protecting drinking water. The status quo puts protections 

for these waters into question, leaving them vulnerable to pollution and degradation.

Americans obtain two-thirds of their drinking water from surface water sources and the 

other one-third from groundwater.108 However, surface water and groundwater are not 

exclusive entities. Groundwater can recharge surface water and surface waters can 

discharge into groundwater. The recharge that occurs from groundwater can be 

significant. In dry regions during the dry season as much as 95% of a stream’s flow can 

come from groundwater.109 Headwater streams and wetlands play a vital role in recharge 

due to their large surface area of soil to water contact.66 If wetlands and small streams 

become altered and lose their connection to groundwater then downstream flow could be 

adversely impacted and may even start to dry up. (p. 13)

Agency Response: See summary response for Section 8.1. In response to public 

comments and in order to increase clarity, the final rule does not include wetlands, 

lakes and ponds as tributaries. See summary response for section 8.2 below. These 

waters may still be considered “waters of the United States” under other provisions 

of the final rule.

Center for Science in Public Participation (Doc. #15426)

8.141 Wetlands, ephemeral streams, intermittent streams, and headwaters provide vital 

ecological functions to downstream rivers. The EPA draft review correctly identifies the 

roles they play in cycling and transport of sediment, nutrients, and contaminants and in 

providing habitat for fauna that move between rivers and other water bodies, and the 

biological connectivity of migratory fauna.

I would encourage EPA to re-examine the definition of a tributary. Currently it is defined 

as having an ordinary high water mark. This is not always the case for important 

 

106 U.S. EPA, EPA 816-K-07-004, FACTOIDS: Drinking Water and Ground Water Statistics for 2007 4 (March

2008), available at http://www.epa.gov/ogwdw/databases/pdfs/data_factoids_2007.pdf.

107 EPA, Geographic Information System Analysis of the Surface Drinking Water Provided by Intermittent,

Ephemeral, and Headwater Streams in the U.S., http://water.epa.gov/lawsregs/guidance/wetlands/

surface_drinking_water_index.cfm (last updated Oct. 29, 2013).

108 Meyer, supra note 57, at 11. [J.L. Meyer, L.A. Kaplan, J.D. Newbold, D.L. Strayer, C.J. Woltemade, J.B. Zedler, 

R. Beilfuss, Q. Capenter, R. Semlitsch, M.C. Watzin, & P.H. Zedler, Where Rivers are Born: The Scientific 

Imperative for Defending Small Streams and Wetlands. American Rivers and Sierra Club 8 (February 2007), 

available at http://www.americanrivers.org/assets/pdfs/ reports-and-publications/WhereRiversAreBorn1d811.pdf? 

422fcb]

109 Id.
Clean Water Rule Response to Comments – Topic 8: Tributaries

123

intermittent and ephemeral streams. The EPA’s SAB suggests changing the definition 

from “ordinary high water mark” to “bed, bank, and other evidence of flow”; I support 

this recommendation.

In Alaska, we expect earlier spring melt, longer dry periods, and a general increase in 

temperatures and precipitation110. Longer dry periods and low snowpack– such as have 

been observed in Prince William Sound111-- could create longer periods during which a 

stream becomes ephemeral or intermittent. Headwater streams that form in rivulets from 

snowmelt may be ephemeral, with no ordinary high water mark, but are critical to the 

physical, biological, and chemical character of downstream waters, particularly those that 

support a salmon ecosystem. A “high water mark” definition also would not include 

streams that form on peatlands, which can be important in supplying flow to streams112, 

but a “bed and bank” definition might be applicable, although the bed and bank 

themselves are peat. A “bed and bank” definition should continue to include water bodies 

– such as off-channel habitat-- that seasonally connect with flowing systems and can be 

important biological habitat. If off-channel habitat such as gravel quarries are utilized as 

“mitigation” for the removal of wetland and aquatic habitat, then these must also come 

under the Clean Water Act for the extent of the period they are in use as mitigation.

Further north, as permafrost melts the land sinks, shifts, cracks and forms new wetlands 

and may form new hydrologic connections to downstream waters. These may not have 

defined ordinary high water marks with bank and bed characteristics. These new freezethaw wetlands along with ephemeral streams and land-locked pockets of water perform 

biological functions, such as mercury methylation113 that can be the basis of a significant 

nexus.

Additionally, ephemeral perched or flow-through ponds, such as those that may form at 

snowmelt or with new wetlands, may have important connections, particularly for 

maintaining groundwater resources114. (p. 1-2)

Agency Response: See summary response for Section 8.1. In response to public 

comments and in order to increase clarity, the final rule does not include wetlands, 

lakes and ponds as tributaries. See summary response for section 8.2 below. These 

waters may still be considered “waters of the United States” under other provisions 

of the final rule. See also TSD section VII for the rationale supporting the decisions 

made in the final rule regarding tributaries. See the Science Report on connectivity 

for discussion of Alaskan streams. See also Section 9 “Scientific Evidence 

Supporting the Rule” of the Response to Comments.

 

110 https://www.snap.uaf.edu/

111 http://www.thecordovatimes.com/article/1420water-supply-crisis-or-conservation; 

http://www.cityofcordova.net/residents/services/water-status/490-water-update-may-22; http://nveyak.com/watershortage-update/

112 Gracz, M, M Moffett, D Siegel, P Glaser. 2014. End member mixing analysis [in a homogenous watershed] to 

identify the contribution of peatlands to stream flow. In prep.

113 Zamzow comment, Docket #EPA-HQ-OA-2013-0582.

114 Rains, M. 2011 Water sources and hydrodynamics of closed-basin depressions, Cook Inlet Region, AK. Wetlands 

31: 377-387; Rains, M. 2008. Surface-water and groundwater interactions in small pools on the Pebble property. 

Powerpoint to federal agencies, Anchorage, AK. November.
Clean Water Rule Response to Comments – Topic 8: Tributaries

124

Natural Resources Defense Council et al. (Doc. #15437)

8.142 THE PROPOSED CATEGORICAL PROTECTIONS FOR TRIBUTARIES AND 

ADJACENT WATERS ARE LEGALLY AND SCIENTIFICALLY JUSTIFIED AND 

MUST BE INCLUDED IN THE FINAL RULE.

...

A. Tributaries

EPA and the Corps propose to define the term “waters of the United States” as including 

all tributaries of traditionally navigable waters, interstate waters, the territorial seas, and 

impoundments of those same waters, thereby categorically extending legal protections to 

all such tributaries. This approach is fully consistent with Justice Kennedy’s “significant 

nexus” test, even though – as discussed above – the Supreme Court’s decisions do not 

require any change in the existing regulations concerning tributaries.115

The scientific justification for categorically protecting tributaries is extremely robust. 

This conclusion is supported by a review and synthesis of more than 1,000 publications 

from the peer-reviewed scientific literature, often referred to as the Connectivity 

Report.116 In that report, EPA concluded that tributaries, as a class, have an undeniable 

impact on downstream navigable waters, stating:

The scientific literature demonstrates that streams, individually or cumulatively, 

exert a strong influence on the character and functioning of downstream waters. 

All tributary streams, including perennial, intermittent, and ephemeral streams, 

are physically, chemically, and biologically connected to downstream rivers via 

channels and associated alluvial deposits where water and other materials are 

concentrated, mixed, transformed, and transported. Headwater streams 

(headwaters) are the most abundant stream type in most river networks and supply 

most of the water in rivers. In addition to water, streams transport sediment, 

wood, organic matter, nutrients, chemical contaminants, and many of the 

organisms found in rivers. Streams are biologically connected to downstream 

waters by the dispersal and migration of aquatic and semiaquatic organisms, 

including fish, amphibians, plants, microorganisms, and invertebrates, that use 

both up- and downstream habitats during one or more stages of their life cycles, 

or provide food resources to downstream communities. Physical, chemical, and 

 

115 Justice Kennedy indicated that an existing regulatory provision that uses the presence of an ordinary high water 

mark to identify the lateral limits of a tributary could itself “provide a reasonable measure of whether specific minor 

tributaries bear a sufficient nexus with other regulated waters to constitute ‘navigable waters’ under the Act.” 547 

U.S. at 781. However, Justice Kennedy did not say that the presence of an OHWM is a necessary prerequisite to 

jurisdiction, and it certainly is not needed if tributaries are shown to have a significant nexus without regard to 

whether a OHWM is present. As proposed, the rule would use OHWM as a guidepost; it proposes to define 

“tributary,” with respect to flowing waters, as any water that: (1) is “physically characterized by the presence of a 

bed and banks and ordinary high water mark,” and that it (2) “contributes flow, either directly or through another 

water,” to a traditionally jurisdictional water. See, e.g., 79 Fed. Reg. at 22,263 (proposed 33 C.F.R. § 328.3(c)(5). As 

discussed below, we are not convinced that these requirements are necessary, but they are certainly sufficient.

116 U.S. EPA, Office of Research & Development, Connectivity of Streams and Wetlands to Downstream Waters: A 

Review and Synthesis of the Scientific Evidence – External Review Draft (Sept. 2013) (hereinafter “Connectivity 

Report”).
Clean Water Rule Response to Comments – Topic 8: Tributaries

125

biological connections between streams and downstream waters interact via 

processes such as nutrient spiraling, in which stream communities assimilate and 

chemically transform large quantities of nitrogen (N) and other nutrients that 

would otherwise increase nutrient loading downstream.117

These conclusions apply equally to very small and infrequently flowing tributary streams. 

According to the Connectivity Report, “Even infrequent flows through ephemeral or 

intermittent channels influence fundamental biogeochemical processes....”118 And 

headwater streams, which are the smallest channels where stream flows begin, are the 

source of approximately 60% of the total mean annual flow to all northeastern U.S. 

streams and rivers, making their impact on the chemical, physical, and biological 

integrity of our waters indisputable.119

These findings have been confirmed by the Science Advisory Board in its peer review of 

the Connectivity Report. In its final report to EPA, the SAB wrote:

The Report concludes that these streams exert a strong influence on the character 

and functioning of downstream waters, and indeed that all tributary streams are 

physically, chemically, and biologically connected to downstream waters. Strong 

scientific support has been provided for this overall conclusion and related 

findings. The SAB notes that there is a gradient of connectivity that is a function 

of the frequency, duration, magnitude, predictability, and consequences of 

physical, chemical, and biological connections. The SAB recommends that the 

conclusions and findings concerning ephemeral, intermittent, and perennial 

streams be quantified when possible, related to the four dimensions of 

connectivity (longitudinal, lateral, vertical and temporal), and discussed with 

additional detail on biogeochemical transformations and biological connections. 

In addition, some hydrologic aspects of connectivity require additional detail; 

these include descriptions of key linkages and exchanges in tributary streams, 

such as groundwater-surface water interactions, and the role of transition areas 

between uplands and headwaters. Likewise, the Report should explain how 

hydrologic connectivity sustains both streams and aquifers, particularly in alluvial 

systems in the Southwest and in karst systems in the eastern United States.120

Although this conclusion should surprise nobody, the fact that the Connectivity Report’s 

assessment that tributaries have a “strong influence” on downstream waters is backed by 

“[s]trong scientific support” is a more than adequate basis on which to conclude that 

tributaries, as a class, have a significant nexus to other covered waters and thus should be 

categorically protected. Indeed, in providing advice to EPA on the proposed rule (as 

opposed to the Connectivity Report), the SAB stated, “[t]here is strong scientific 

 

117 Id. at 1-3.

118 Id. at 1-7.

119 Id.

120 U.S. EPA Science Advisory Board, SAB Review of the Draft EPA Report Connectivity of Streams and Wetlands 

to Downstream Waters: A Review and Synthesis of the Scientific Evidence, EPA-SAB-15-001, at 3-4 (Oct 17, 2014) 

(hereinafter “SAB Connectivity Review”), available at 

http://yosemite.epa.gov/sab/sabproduct.nsf/fedrgstr_activites/AF1A28537854F8AB85257D74005003D2/$File/EPA

-SAB-15-001+unsigned.pdf.
Clean Water Rule Response to Comments – Topic 8: Tributaries

126

evidence to support the EPA’s proposal to include all tributaries within the jurisdiction of 

the Clean Water Act.”121

Ensuring that tributaries are covered under the Clean Water Act’s pollution control 

programs frequently means cleaner water for larger downstream rivers, estuaries, and 

oceans. Even when they are not helping to make downstream waters better, tributaries 

have significant impacts on the biological, chemical, and physical condition of 

downstream waters: pollution dumped into streams high up in the watershed can cause 

harm in larger water bodies (a classic example being the Gulf of Mexico “Dead Zone”); 

and filling in upstream tributaries can dramatically alter the physical hydrology of 

downstream waters (a simple example is a dam built to divert flow from the tributary to 

an industrial use). It is both intuitive and demonstrably true that processes occurring 

upstream within these small bodies of water affect the entire river network’s structure and 

function. As the Connectivity Report shows, the science conclusively establishes that 

tributaries have not only significant but overwhelming effects on downstream navigable 

waters. The proposal’s categorical protections for tributaries are both justified and 

compelled by these findings, and they must be included in the final rule. (p. 32-34)

Agency Response: The agencies agree that those features meeting the definition of 

“tributary” in the final rule have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. The final rule categorically considers tributaries, as defined in the rule that 

are not otherwise excluded under paragraph (b) to be waters of the United States.

See also Section 9 “Scientific Evidence Supporting the Rule” of the Response to 

Comments.

Defenders of Wildlife and Patagonia Area Resource Alliance (Doc. #16394)

8.143 Finally, Defenders also objects to the limitation in the definition of tributaries in proposed

subsection (u)(5) to waters identified in subsections (s)(1) through (s)(4). This definition 

should include tributaries to waters identified in subsections (s)(6) and (s)(7) as well. 

There is no principled scientific or legal basis to exclude tributaries to any waters of the 

U.S. from the Act’s jurisdiction.

In short, the inclusion of tributaries in the definition of waters of the U.S. is solidly 

grounded in science and the law and is required by the purpose and intent of the Act. See 

Chevron, USA v. NRDC, 467 U.S. 837, 842-43 (1984). At a minimum, including 

tributaries as waters of the United States is a reasonable interpretation of the Clean Water 

Act, while excluding them would be inconsistent with the science in the record and the 

purpose and intent of the statute and an impermissible interpretation of the agency’s 

authority. See id. Defenders urges the agencies to retain the inclusion of tributaries in the 

final definition and strengthen it as noted above. (p. 8)

 

121 U.S. EPA Science Advisory Board, Science Advisory Board (SAB) Consideration of the Adequacy of the 

Scientific and Technical Basis of the EPA’s Proposed Rule titled “Definition of Waters of the United States under 

the Clean Water Act,” EPA-SAB-14-007, at (Sept. 30, 2014) (hereinafter “SAB Rule Review”), available at 

http://yosemite.epa.gov/sab/sabproduct.nsf/0/518D4909D94CB6E585257D6300767DD6/$File/EPA-SAB-14-

007+unsigned.pdf.
Clean Water Rule Response to Comments – Topic 8: Tributaries

127

Agency Response: See summary response for Section 8.1. The agencies’ 

interpretive task in this rule – determining which waters have a “significant nexus” 

– requires the integration of the science with policy judgment and legal 

interpretation. The final rule categorically considers tributaries, as defined in the 

rule that are not otherwise excluded under paragraph (b) to be waters of the United 

States. Section III(C) of the preamble and Section VII of the Technical Support 

Document discuss the science supporting the agencies’ determination that waters 

meeting the definition of “tributary” have a significant nexus because they 

significantly affect the chemical, physical, and biological integrity of traditional 

navigable waters, interstate waters, and the territorial seas. Section I of the 

Technical Support Document describes the legal basis of the final rule, including its 

consistency with the statute and case law.

Waterkeeper Alliance et al. (Doc. #16413)

8.144 III. ALL TRIBUTARIES TO ANY OTHER WATER OF THE U.S. MUST CONTINUE 

TO BE INCLUDED IN THE DEFINITION.

The Proposed Definition improperly narrows jurisdiction over tributaries. First, it limits 

jurisdiction to tributaries of traditionally navigable waters, interstate waters, territorial 

seas, and impoundments. Second, it improperly relies on the "significant nexus test" as 

the sole basis for asserting jurisdiction. Third, it adopts a new definition of tributaries that 

reduces the types of tributaries covered by the rule in a manner that is not supported by 

law and science. Fourth, it categorically exempts "ditches" from coverage even if the 

ditches are otherwise tributaries contrary to law and science.

Under the agencies' existing regulations, all tributaries to traditionally navigable waters, 

interstate waters, impoundments, and "other waters" are defined as "waters of the United 

States."122 All of the tributaries protected under the existing regulation must continue to 

be covered in the Proposed Definition. As demonstrated previously, the Supreme Court 

has not issued any opinion that limits the jurisdiction over tributaries. To the contrary, it 

is well settled that tributaries are jurisdictional waters within the meaning of "waters of 

the United States."123 Neither SWANCC nor Rapanos invalidated or limited the scope of 

jurisdiction provided by the existing definition's inclusion of tributaries.124 Additionally, 

all tributaries to all other "water of the United States" must be included with the 

definition and given categorical protection. Tributaries are obviously connected, and thus 

adversely impact, their downstream waters. This is consistent with the findings of the 

 

122 See e.g., 40 C.F.R. §122.2; 33 C.F.R. § 328.3(a).

123 See, e.g., N. Cal. River Watch v. City of Healdsburg, 496 F.3d 993, 997 (9th Cir. 2007) ("The Supreme Court has 

since confirmed that regulable waters of the United States include tributaries of traditionally navigable waters and 

wetlands adjacent to navigable waters and their tributaries. The only question reserved in Riverside Bayview Homes

was the issue of CWA jurisdiction over truly isolated waters." citing Bayview, 474 U.S. at 106; 33 C.F.R. 

328.3(a)(1),(4),(7); and Rapanos, 547 U.S. at 792 n. 3); see also Benjamin v. Douglas Ridge Rifle Club, 673 

F.Supp.2d 1210,1215 & n. 2 (D. Or. 2009) (indicating that jurisdiction over tributaries did not require demonstration 

of significant nexus); United States v. Vierstra, 2011 WL 1064526, at '5 (D. Id. Mar. 18, 2011) [“It is an open 

question as to whether Justice Kennedy's concurrence applies in the tributary context."). But see, e.g., United States 

v. Robison, 505 F.3d 1208 (11th Cir 2007) (applying "significant nexus" analysis to tributary stream).

124 See 2011 Comments, supra note 48, at pp. 9-15; see also 2003 Comments, supra note 36 at pp. 46.
Clean Water Rule Response to Comments – Topic 8: Tributaries

128

Connectivity Report and the SAB Report, as well as the individual comment of the SAB 

members.125 (p. 26-27)

Agency Response: See summary response for Section 8.1. The agencies’ 

interpretive task in this rule – determining which waters have a “significant nexus” 

– requires the integration of the science with policy judgment and legal 

interpretation. The final rule categorically considers tributaries, as defined in the 

rule that are not otherwise excluded under paragraph (b) to be waters of the United 

States. Section III(C) of the preamble and Section VII of the Technical Support 

Document discuss the science supporting the agencies’ determination that waters 

meeting the definition of “tributary” have a significant nexus because they 

significantly affect the chemical, physical, and biological integrity of traditional 

navigable waters, interstate waters, and the territorial seas. See also Section 9 

“Scientific Evidence Supporting the Rule” of the Response to Comments. Section I 

of the Technical Support Document describes the legal basis of the final rule, 

including its consistency with the statute and caselaw.

8.145 Another SAB member similarly commented that the Proposed Definition should allow 

"flexibility to for [sic] field personnel to define functional tributaries, even where those 

functional tributaries might lack obvious indicators of bed and bank (e.g., alluvial 

deposits on the bed of a headwater stream in a humid mountain 8 G setting) but have less 

obvious indicators of tributary flows (e.g., directionally bent herbaceous vegetation and 

subtle debris lines in swales connecting vernal pools to downstream waters in arid and 

semi-arid settings)."126 (p. 33)

Agency Response: In this final rule, the agencies are responding to requests from 

across the country to make the process of identifying waters protected under the 

CWA easier to understand, more predictable, and more consistent with the law and 

peer-reviewed science. See summary response 8.1.2 below and TSD section VII(A)

for further explanation. See also Section 9 “Scientific Evidence Supporting the 

Rule” of the Response to Comments.

Association of State Floodplain Managers, Inc. (Doc. #19452)

8.146 The proposed rule recognizes the importance of protecting and managing stream 

networks in totality – including tributaries – to maintain the physical, chemical, and 

biological integrity of navigable waters.

All components of the stream continuum function together to protect the following: 

physical (channel and channel bank integrity), natural flood water storage, chemical (e.g. 

drinking water) and biological (e.g. habitat and migration) ecological services. These 

services are interrelated and not addressed by protection of only limited reaches of a 

stream. ASFPM supports the fundamental definition of streams and their tributaries in the 

proposed rule, based on the presence of physical structure which may include a bed, 

 

125 Compilation of Preliminary Comments from Individual Panel Members on the Scientific and Technical Basis of 

the Proposed Rule Title "Definition of 'Waters of the United States' Under the Clean Water Act" (August 14, 2014) 

(hereinafter "Member Comments").

126 Member Comments, supra note 72, Rains at 71.
Clean Water Rule Response to Comments – Topic 8: Tributaries

129

banks, floodplain and evidence of flow. This approach is consistent with most state legal 

definitions. It may, however, be helpful to discuss in more detail what the agencies are 

describing when they use the term “ephemeral” as it is used in the preamble to the 

proposed rule (or in future guidance), given that this term is defined differently by 

various states from both a legal and a scientific perspective. In addition some discussion 

of how the methodology used to identify streams takes into consideration their 

contribution to the physical, chemical, and/or biological integrity of navigable waters is 

recommended. (p. 4)

Agency Response: The preamble to the final rule describes ephemeral streams as 

those that “have flowing water only in response to precipitation events in a typical 

year, and are always above the water table.” Section III(C) of the preamble 

describes the agencies’ determination that waters meeting the definition of 

“tributary” have a significant nexus because they significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas.

American Association of Port Authorities (Doc. #13559)

8.147 AAPA members have also expressed concern that the proposed treatment of “tributary” 

and “adjacent” waters will result in a significant expansion of features (both natural and 

artificial) subject to regulation as “waters of the United States.” Definitions like “all 

tributaries” and “all waters adjacent” are too broad and could impact port facilities. We 

recommend clarification of these definitions. 

AAPA is concerned with the term “contributes flow,” as no distinction is made between 

perennial, intermittent or ephemeral flows. This represents a significant departure from 

the current “continuous surface connection” standard. Under the proposed definition, 

most, if not all, of a port’s stormwater collection infrastructure, consisting of open ditches 

and canals (representing perennial, intermittent and ephemeral storm flows), could be 

considered “waters” if they have a permeable bed and banks and an ordinary high water 

mark (OHWM). We recommend further clarification of this definition. (p. 1-2)

Agency Response: See summary response for Section 8.1. Section III(C) of the 

preamble describes the agencies’ determination that waters meeting the definition of 

“tributary” have a significant nexus because they significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas. Section VII of the Technical Support Document discusses 

the science supporting the agencies’ conclusion, see specifically section VII(B). 

Paragraph (b) of the final rule excludes many features from consideration as waters 

of the United States, including most ditches that are not relocated tributaries or 

excavated in tributaries and stormwater control features created in dry land. 

Section IV(I) of the preamble to the final rule and the summary responses in 

Compendium 7 of this RTC, “Features and Waters Not Jurisdictional,” provide a 

broad discussion of the final rule’s exclusions. See summary response for section 

6.2, “Excluded Ditches” in this RTC for a more focused discussion of revised and 

clarified ditch exclusions.
Clean Water Rule Response to Comments – Topic 8: Tributaries

130

The Association of State Wetland Managers (Doc. #14131)

8.148 6. The proposed rule recognizes the importance of protecting and managing stream 

networks in totality – including tributaries – to maintain the physical, chemical, and 

biological integrity of navigable waters.

All components of the stream continuum function together to protect physical (e.g. water 

supply), chemical (e.g. drinking water) and biological (e.g. habitat and migration) 

ecological services. These services are interrelated and cannot be maintained by 

protection of only limited reaches of a stream. ASWM supports the fundamental 

definition of streams and their tributaries in the proposed rule, based on the presence of 

physical structure (a bed, banks, and evidence of flow). This approach is consistent with 

most state legal definitions. It may, however, be helpful to discuss in more detail what the 

agencies are describing when they use the term “ephemeral” as it is used in the preamble 

to the proposed rule (or in future guidance), given that this term is defined differently by 

various states from both a legal and a scientific perspective. In addition, some discussion 

of how the methodology used to identify streams takes into consideration their 

contribution to the physical, chemical, and/or biological integrity of navigable waters is 

recommended.127 (p. 3-4)

Agency Response: The preamble to the final rule describes ephemeral streams as 

those that “have flowing water only in response to precipitation events in a typical 

year, and are always above the water table.” Section III(C) of the preamble 

describes the agencies’ determination that waters meeting the definition of 

“tributary” have a significant nexus because they significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas.

Earthjustice (Doc. #14564)

8.149 Subsection (s)(5) identifies tributaries and it makes the same error as (s)(4). Again, there 

is no scientific or legal reason to exclude tributaries of any water that is identified as a 

water of the U.S. through this rule. Tributaries plainly affect downstream waters and if 

the downstream water is a water of the U.S. then its tributaries must be protected under 

the Clean Water Act. Indeed, a predecessor to the Clean Water Act recognized over a 

century ago that tributaries must receive federal protection from pollution. 33 U.S.C. 

§407. In enacting the comprehensive Clean Water Act, designed in part as a successor to 

that prior law, 33 U.S.C. §1342(a)(4) and (5), Congress clearly did not intend to cut back 

on the prior law’s safeguards for tributaries. In short, including these tributaries is 

required under Chevron Step One and would, at least, be a permissible and reasonable 

interpretation of the Act that comports with Step Two of Chevron. Conversely, given the 

Act’s broad protective scope and the scientific evidence that these tributaries have a 

hydrologic connection with covered waters and significantly affect them, excluding them 

 

127 ASWM recently compiled a Report on State Definitions, Jurisdiction and Mitigation Requirements in State 

Programs for Ephemeral, Intermittent and Perennial Streams in the United States (April, 2014), with financial 

support from EPA. This report may be downloaded at http://aswm.org/stream_mitigation/streams_in_the_us.pdf.
Clean Water Rule Response to Comments – Topic 8: Tributaries

131

would fail under Step Two—and would not constitute reasoned decisionmaking 

supported by the record. (p. 6)

Agency Response: The agencies’ interpretive task in this rule – determining 

which waters have a “significant nexus” – requires the integration of the science 

with policy judgment and legal interpretation. The final rule categorically considers 

tributaries, as defined in the rule that are not otherwise excluded under paragraph 

(b) to be waters of the United States. Section I of the Technical Support Document 

describes the legal basis of the final rule, including its consistency with the statute 

and case law.

Center for Rural Affairs (Doc. #15029)

8.150 We are generally supportive of providing clarity to the regulated community by 

establishing tributaries to traditionally navigable waters, interstate waters, territorial seas, 

and impoundments ((a)(1) through (4) waters) as per se jurisdictional. Tributaries, 

especially headwater tributaries, greatly affect the chemical, physical, and biological 

integrity of (a)(1) through (4) waters by contributing flow and pollutants, impacting the 

geomorphology of the water bodies, and providing additional aquatic habitat. Given the 

impact of tributaries, it would be unreasonable to argue that they lack a significant nexus 

to waters of the United States. (p. 2)

Agency Response: The agencies agree that those features meeting the definition of 

“tributary” in the final rule have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. The final rule categorically considers tributaries, as defined in the rule that 

are not otherwise excluded under paragraph (b) to be waters of the United States. 

National Parks Conservation Association (Doc. #15130)

8.151 Recent regulatory uncertainties especially threaten headwater, ephemeral, and 

intermittent streams as well as other upstream areas that feed into park units. About 117 

million (one-third of Americans) – and many park visitors – depend on drinking water 

from public water systems that are fed in whole or in part by intermittent, headwater, or 

ephemeral streams (EPA 2009). For the past 13 years, confusion resulting from both the 

Supreme Court decisions and agency guidance particularly muddied the protection status 

of these types of waters, which respectively comprise 53 percent (headwater, see Figure 2 

in Appendix) and 59 percent (intermittent and ephemeral, see Figure 3 in Appendix) of 

total stream length in the United States, excluding Alaska (Nadeau and Rains 2007; 

Levick et al. 2008). The new rule provides a clear standard for treating these streams as 

jurisdictional tributaries (EPA Federal Register 2014, 22206), which benefits water 

quality and availability in downstream parks.

Headwaters include streams where surface water first collects and converges into visible 

channels. They provide the original source of water for watersheds by supplying more 

than half of the water volume of higher-order streams (Alexander et al. 2007), and as 

such they strongly indicate water quality, biological content, and habitat quality in 

downstream systems (Dodds and Oakes 2008; Snyder et al. 2013; Clarke et al. 2008; Finn 
Clean Water Rule Response to Comments – Topic 8: Tributaries

132

et al. 2011).128 Also, due to their large spatial coverage, headwater networks are major 

entry points for non-point source pollution into riparian networks around parks.129

Ironically, headwater, intermittent, and ephemeral streams, which science shows are 

important to protecting water quality and wildlife habitat, are the very waters at risk 

because of policy and legal decisions. Because these decisions called into question 

protections for streams without “strong connectivity” to traditionally navigable 

waterways, headwater streams potentially lost protection because 50 percent are 

seasonally ephemeral or intermittent (Nadeau and Rains 2007). Ephemeral and 

intermittent streams do not continually flow into higher order streams throughout the 

year. However, they still substantially affect traditionally navigable waterways (EPA 

Federal Register 2014). According to the EPA, ephemeral and intermittent streams:

“provide landscape hydrologic connections; stream energy dissipation during 

high-water flows to reduce erosion and improve water quality; surface and 

subsurface water storage and exchange; ground-water recharge and discharge; 

sediment transport, storage, and deposition to aid in floodplain maintenance and 

development; nutrient storage and cycling; wildlife habitat and migration 

corridors; support for vegetation communities to help stabilize stream banks and 

provide wildlife services; and water supply and water-quality filtering” (Levick et 

al. 2008).

In terms of biological connectivity, the extensive spatial coverage of headwater, 

ephemeral, and intermittent streams allows these areas to host large portions of an entire 

river system’s biodiversity (for macro invertebrates, see Finn et al. 2011; for microbes, 

plants, and other animals, see Meyer et al. 2003 and 2007). Scientists have repeatedly 

shown that the water quality of headwater streams directly affects biological (through 

nutrient concentration and flux) and chemical (Peterson et al. 2001) signatures of higherorder stream features and downstream water bodies (Lowe and Likens 2005; Gomi, Sidle, 

and Richardson 2002). All of these scientific considerations have direct implications for 

how these streams affect national park waters.

In addition to protecting scientifically-important headwater, ephemeral, and intermittent 

streams themselves, the rule also provides for the evaluation of these waters in 

“networks” and aggregation of small features. When considered together, these networks 

represent a collection of waters with strong connectivity to downstream water bodies and 

other features (Gomi, Sidle, and Richardson 2002), like park units. Taken individually, 

small streams in headwater systems may not always display discretely significant 

contributions to higher order streams; however, their strong biological and chemical 

connections become more apparent when headwater streams are analyzed as the networks 

 

128 Areas with headwaters overlap many national park unit boundaries such as Shenandoah, Yellowstone, and Rocky 

Mountain National Parks.

129 NPS studies show that nonpoint source pollution and sedimentation are responsible for more than 70 percent of 

the known threats to park water quality and wetland loss. National park lands surrounding headwaters and streams 

provide important cleansing services by regulating nutrient and pollutant loads, but this filtering capacity can be 

degraded overtime if it is overtaxed, as was observed to some extent, for example, in Great Smoky Mountain 

National Park (Cai et al., 2010).
Clean Water Rule Response to Comments – Topic 8: Tributaries

133

that science has clear methods for identifying (e.g., see NCDWQ 2010 and various 

guidance documents from USACE).130 (p. 1-3)

Agency Response: The agencies agree that those features meeting the definition of 

“tributary” in the final rule have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. The final rule categorically considers tributaries, as defined in the rule that 

are not otherwise excluded under paragraph (b) to be waters of the United States. 

Endangered Habitats League (Doc. #3384)

8.152 EHL supports the many important clarifications provided by the Clean Water Protection 

Rulemaking, including defining "tributary" for the first time and affirming once again 

that Waters of the U.S. categorically include all tributaries to Traditional Navigable 

Waters (TNW) and interstate waters. (p. 2)

Agency Response: See summary response for section 8.1.

George Washington University Regulatory Studies Center (Doc. #13563)

8.153 Under the proposed rule, all tributaries are now per se or categorically jurisdictional. 

“Tributaries” are defined as being “a water physically characterized by the presence of a 

bed and banks and ordinary high water mark...which contributes flow, either directly or 

through another water to a water identified in paragraphs (a)(1) through (4),” those 

traditional navigable waters, interstate waters, territorial seas and impoundments of these 

same waters identified in those sections. Wetlands, lakes, and ponds are all tributaries, 

even without a bed and bank or ordinary high water mark, if they deliver flow directly or 

through another water identified in (a)(1) through (a)(3). Neither “bank” nor “flow” is 

defined in the rule, raising questions as to whether or not magnitude or duration or 

seasonality of the flow matters in these circumstances. (p. 4)

Agency Response: See summary response for section 8.1. In response to public 

comments and in order to increase clarity, the final rule does not include wetlands, 

lakes and ponds as tributaries. See summary response for section 8.2 below.

Citizens Campaign for the Environment (Doc. #14967)

8.154 This rule will allow the EPA to once again protect critical streams and wetlands while 

restoring the vital water protection measures originally promised in the Clean Water Act. 

The latest peer-reviewed science supports the assertion that wetlands and streams are 

essential to supporting the larger lakes, rivers, and estuaries, which are currently under 

federal protections. These waters are hydrologically connected and dependent upon each 

 

130 Overzealous application of the aggregation concept is prevented by the rule’s requirement that the case-specific 

scientific analysis of aggregations be “more than speculative or insubstantial,” as Justice Kennedy suggested. 

Furthermore, delineations of streams with significant nexuses are fairly reliable in areas with healthy bank 

vegetation, which helps channel locations to not naturally move over time; this is especially true in mountainous 

areas which contain many headwaters with winter permafrost that hardens banks and slows stream flow (Crawford 

and Stanley 2014).
Clean Water Rule Response to Comments – Topic 8: Tributaries

134

other, and failing to protect streams and wetlands puts local waterways and recreational 

economies at risk. CCE supports providing clear and predictable protections for streams, 

wetlands, and other waters that are currently vulnerable. It does this in part by providing 

a clearer, scientifically supported definition of tributaries than in the past, stating that 

streams must have a defined bed, bank, and ordinary high water mark and flow to water 

already covered by the Act. (p. 2)

Agency Response: The agencies agree that those features meeting the definition of 

“tributary” in the final rule have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. The final rule categorically considers tributaries, as defined in the rule that 

are not otherwise excluded under paragraph (b) to be waters of the United States. 

In response to public comments and in order to increase clarity, the final rule does 

not include wetlands, lakes and ponds as tributaries. See summary response for 

section 8.2 below. These waters may still be considered “waters of the United 

States” under other provisions of the final rule. 

Neuse Riverkeeper Foundation (Doc. #15095)

8.155 The EPA should ensure that the new rule:

...

2. FULLY PROTECTS JURISDICTIONAL COVERAGE OF ALL TRIBUTARIES: 

The definition should not require the presence of an Ordinary High Water Mark, should 

not categorically exclude ditches that meet the definition of a tributary, and should 

protect tributaries to all WOTUS (not just TNWs, Interstate Waters, Territorial Seas and 

Impoundments). Additionally, the agencies should maintain all jurisdictional bases for 

categorically protecting tributaries. 

... (p. 2)

Agency Response: See Summary response to Section 8.1. The agencies’ 

interpretive task in this rule – determining which waters have a “significant nexus” 

– requires the integration of the science with policy judgment and legal 

interpretation. The final rule categorically considers tributaries, as defined in the 

rule that are not otherwise excluded under paragraph (b) to be waters of the United 

States.

Competitive Enterprise Institute et al. (Doc. #15127)

8.156 According to the proposed rule, a “tributary” will be “a water physically characterized by 

the presence of a bed and banks and ordinary high water mark, . . . which contributes 

flow, either directly or through another water,” to waters over which the Agencies have 

proper jurisdiction. 79 Fed. Reg. at 22,272. Breaks in that flow, natural or man-made, do 

not cause a water to “lose its status as a tributary . . . so long as a bed and banks and an 

ordinary high water mark can be identified upstream of the break.” Id. The term 
Clean Water Rule Response to Comments – Topic 8: Tributaries

135

“ordinary high water mark,” which is crucial to determining “tributary” under the 

proposed rule, is not itself clearly defined.131

At first glance, the proposed definition appears to be little more than the recitation of the 

physical characteristics of a body of water—bed, banks, high water mark. Yet a closer 

look reveals that the proposed definition expands the concept of “tributaries” to include 

dry land over which water occasionally flows. As the explanatory notes accompanying 

the proposed rule make explicit, “[a] bed and banks and ordinary high water mark . . . . 

can be created by ephemeral, intermittent, and perennial flows.” Id. at 22,202. And such 

ephemeral and intermittent waters need not contribute flow directly to navigable waters, 

so long as some circuitous route can be traced through a series of other waters. Thus, if 

the Agencies can show, for example, that the runoff in an ordinarily dry drainage ditch at 

the side of the road leads, at times of extreme weather, to other ditches that themselves 

eventually feed into navigable waters, the Agencies can claim that that ditch is a “water 

of the United States.” (p. 5-6)

Agency Response: See summary response for Section 8.1. The term “ordinary 

high water mark” has been defined in Corps regulations since 1986, and used by 

Corps Districts nationwide to determine the lateral limits of jurisdiction over nontidal water bodies for the CWA section 404 permitting program. Paragraph (b) of 

the final rule excludes many features from consideration as waters of the United 

States, including most ditches that are not relocated tributaries or excavated in 

tributaries. Section IV(I) of the preamble to the final rule and the summary 

responses in Compendium 7 of this RTC, “Features and Waters Not Jurisdictional,” 

provide a broad discussion of the final rule’s exclusions. See summary response for 

section 6.2, “Excluded Ditches” in this RTC for a more focused discussion of revised 

and clarified ditch exclusions.

The River Alliance of Wisconsin (Doc. #16344)

8.157 RECOMMENDATION: River Alliance recommends that the definition of tributary in 

(u)(5) be broadened to incorporate a more scientific understanding of what constitutes a 

tributary.

When read in conjunction with the definition of tributaries in (u)(5), we are concerned 

that this is an overly narrow definition of a tributary. There are many waters that would 

be excluded from CWA protection if they had to be characterized as having a bed, bank 

and ordinary high water mark. And yet these “non-conforming” tributaries still transport 

pollutants from the land and have a significant impact on quality and quantity of 

downstream waters is indisputable. SAB reviewers made suggestions including 

modifying the definition to read “having a bed, bank and sometimes an ordinary high 

water mark” to capture groundwater-fed stream. Other reviewers commented that the 

definition needs to capture the important intermittent flows that exert a strong influence 

on downstream systems. (p. 2)

 

131 To the extent that the Agencies intend to elucidate the meaning of “ordinary high water mark,” or other central 

terms, outside of this rulemaking, that would only confirm that the proposed rule is incomplete. Attempts to define 

such terms through guidance, blog posts, etc., would be an improper attempt to circumvent the requirements of the 

Administrative Procedures Act.
Clean Water Rule Response to Comments – Topic 8: Tributaries

136

Agency Response: The agencies’ interpretive task in this rule – determining 

which waters have a “significant nexus” – requires the integration of the science 

with policy judgment and legal interpretation. The final rule categorically considers 

tributaries, as defined in the rule that are not otherwise excluded under paragraph 

(b) to be waters of the United States. See also Section 9 “Scientific Evidence 

Supporting the Rule” of the Response to Comments.

Wyoming Outdoor Council (Doc. #16528)

8.158 Under the proposed regulations "tributaries of waters" that are identified in paragraphs 

(a)(l)-(4) (or (i)-(iv)) of the various regulatory modifications would be defined by rule as 

"waters of the United States." This would include tributaries to traditional navigable 

waters, interstate waters, the territorial seas, and impoundments. Tributaries would be 

defined as waters with a bed and banks and an ordinary high water mark, or wetlands, 

lakes, or ponds that contribute flow directly or indirectly to an (a)(l)-(4) water. Man-made 

or natural breaks would not cause a tributary to lose its status. Tributaries, including 

wetlands, could be natural, man-altered, or man-made. In addition, impoundments would 

not cause a loss of tributary status, and the definition of tributary would apply to 

perennial, intermittent, and ephemeral waters.

We encourage the EPA and the Corps to maintain these provisions in the final rule. We 

believe they are well justified. (p. 2)

Agency Response: The agencies agree that those features meeting the definition of 

“tributary” in the final rule have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. The final rule categorically considers tributaries, as defined in the rule that 

are not otherwise excluded under paragraph (b) to be waters of the United States. 

In response to public comments and in order to increase clarity, the final rule does 

not include wetlands, lakes and ponds as tributaries. See summary response for 

section 8.2 below. These waters may still be considered “waters of the United 

States” under other provisions of the final rule. 

Tennessee Clean Water Network et al. (Doc. #16537)

8.159 We support the science-based determination that all tributaries, including "ephemeral" 

and "intermittent" streams, are categorically waters of the United States because they are 

physically, chemically and biologically connected to traditionally navigable waters. The 

proposed rule clarifies which small streams and headwaters are covered by the Act. 

Paragraph (s)(5) recognizes "tributaries" as waters of the United States, and defines 

"tributary" as "a water physically characterized by the presence of a bed and banks and 

ordinary high water mark, as defined at 33 C.F.R. § 328.3(e), which contributes flow, 

either directly or through another water, to a water identified in paragraphs (s)(l) through 
Clean Water Rule Response to Comments – Topic 8: Tributaries

137

(4) of [the proposed Rule]."132 Tributaries are further defined to include wetlands, lakes, 

ponds, and-notably-headwater streams.133 (p. 2)

Agency Response: The agencies agree that those features meeting the definition of

“tributary” in the final rule have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. The final rule categorically considers tributaries, as defined in the rule that

are not otherwise excluded under paragraph (b) to be waters of the United States. 

In response to public comments and in order to increase clarity, the final rule does 

not include wetlands, lakes and ponds as tributaries. These waters may still be 

considered “waters of the United States” under other provisions of the final rule. 

See summary response for section 8.2 below.

Kentucky Waterways Alliance (Doc. #16581)

8.160 EPA and the Corps propose to define the term “waters of the United States” as including 

all tributaries of traditionally navigable waters, interstate waters, the territorial seas, and 

impoundments of those same waters, thereby categorically extending legal protections to 

all tributaries. This approach is fully consistent with the “significant nexus” test. The 

agencies have proposed a definition of “tributary” that ensures that the term includes all 

tributaries that reliably have a “significant nexus” to downstream waters. The core 

standards for a tributary under this proposed definition are that it (1) is “physically 

characterized by the presence of a bed and banks and ordinary high water mark,”[14] and 

that it (2) “contributes flow, either directly or through another water,” to a traditionally 

jurisdictional water. This definition builds upon the currently applicable one, which does 

not require the presence of a bed and banks.

The scientific justification for categorically protecting tributaries meeting this definition 

is extremely robust. The definition is supported by EPA’s Connectivity Report, a review 

and synthesis of more than 1,000 publications from the peer-reviewed scientific 

literature.134 In that report, EPA concluded that tributaries, under the proposed definition, 

as a class, have an undeniable impact on downstream navigable waters, stating:

The scientific literature demonstrates that streams, individually or cumulatively, 

exert a strong influence on the character and functioning of downstream waters. 

All tributary streams, including perennial, intermittent, and ephemeral streams, 

are physically, chemically, and biologically connected to downstream rivers via 

channels and associated alluvial deposits where water and other materials are 

concentrated, mixed, transformed, and transported. Headwater streams 

(headwaters) are the most abundant stream type in most river networks and supply 

most of the water in rivers. In addition to water, streams transport sediment, 

wood, organic matter, nutrients, chemical contaminants, and many of the 

 

132 Definition of "Waters of the United States" Under the Clean Water Act, 79 Fed. Reg. 22,188, 22,269 (proposed 

Apr. 21, 2014)(tobecodifiedat40C.P.R.pts.110, 112, 116, 117, 122, 230, 232, 300, 302 & 401).

133 Id.

134 U.S. EPA, Office of Research & Development, Connectivity of Streams and Wetlands to Downstream Waters: A 

Review and Synthesis of the Scientific Evidence – External Review Draft (Sept. 2013) (hereinafter “Connectivity 

Report”).
Clean Water Rule Response to Comments – Topic 8: Tributaries

138

organisms found in rivers. Streams are biologically connected to downstream 

waters by the dispersal and migration of aquatic and semi-aquatic organisms, 

including fish, amphibians, plants, microorganisms, and invertebrates, that use 

both up- and downstream habitats during one or more stages of their life cycles, 

or provide food resources to downstream communities. Physical, chemical, and 

biological connections between streams and downstream waters interact via 

processes such as nutrient spiraling, in which stream communities assimilate and 

chemically transform large quantities of nitrogen (N) and other nutrients that 

would otherwise increase nutrient loading downstream.135

These conclusions apply equally to very small and infrequently flowing tributary streams. 

According to the Connectivity Report, “Even infrequent flows through ephemeral or 

intermittent channels influence fundamental biogeochemical processes....”136 And 

headwater streams, which are the smallest channels where stream flows begin, are the 

source of approximately 60% of the total mean annual flow to all northeastern U.S. 

streams and rivers, making their impact on the chemical, physical, and biological 

integrity of our waters indisputable.137

Categorical protection of all tributaries, including headwaters is essential, because 

tributaries connect the river network and provide vital ecosystem functions. The 

importance of headwater streams and wetlands to the health of larger, navigable rivers in 

Kentucky, like the Ohio, Green, Tennessee, Cumberland, Kentucky, Mississippi, Big 

Sandy, and Licking Rivers.

In fact, in Kentucky, of the 92,000 stream miles, EPA estimates that at a minimum, 55% 

of streams have no upstream tributary, and at least 29% of streams are intermittent or 

ephemeral.138 Recent efforts by EPA to map the waters of the U.S., including ephemeral 

and intermittent streams, show this number could be even higher, with up to 51,960 

stream miles being intermittent or ephemeral – or 65% of the state’s stream network.139

Intermittent, ephemeral, or headwater streams in Kentucky are critically important for a 

number of reasons. First and foremost, for human use, these streams make up a 

considerable amount of stream miles in drinking water source protection areas (SPA).

 3,282,980 = total population served by public drinking water systems relying on 

I/E/H

 15,064.8 = total stream miles in SPA

 8,184.7 = miles of I/E/H in SPAs

 

135 Id. at 1-3.

136 Id. at 1-7.

137 Id.

138 Natural Resources Defense Council, Missing Protection: Polluting the Mississippi River Basin’s Small Streams 

and Wetlands. NRDC Issue Paper, p. 21 (2008).

139 U.S. Environmental Protection Agency: Streams and Waterbodies Maps, the National Hydrography Dataset, 

High

Resolution (October, 2013). Prepared by INDUS Corporation under contract with U.S. EPA, Office of Water, and 

published on the House Committee on Science, Space, and Technology webpage: http://science.house.gov/epamaps-state-2013
Clean Water Rule Response to Comments – Topic 8: Tributaries

139

 54% = % of streams in SPAs that are I/E/H140

These streams are likewise critical resources for ecosystems in Kentucky. In Appalachia, 

headwater streams have been the recipient of the catastrophic impacts of surface coal 

mining operations. As a result of these operations, thousands of miles of headwaters 

streams have been altogether removed from the Appalachian Mountain landscape. The 

impacts, however, do not halt at the mining site. These sites, and the waterways that 

formerly occupied the sites, are connected to downstream waterways. The result of 

impacts upstream, and the filling of streams with toxic waste from surface mining 

processes, has caused downstream biological and fish communities to decrease.141 142

The connectivity of headwater tributaries to downstream impacts is not only illustrated in 

Appalachia of Kentucky, but in Kentucky’s other bioregions as well. Many areas of 

Kentucky have limestone geology that is rich in phosphorus. As a result, much of 

Kentucky’s soils are equally rich in phosphorus. Often, in the Bluegrass Region and 

down into the Pennyrile region, farmers’ lands host ephemeral and intermittent waters, as 

well as perennial waters. Farming operations that do not utilize responsible nutrient 

management practices can lead to the transport of sediment laden with high phosphorus 

into downstream waters. In fact, Kentucky is the 5th leading source of phosphorus to the 

Gulf of Mexico Dead Zone, even though we have significantly less farming acreage than 

other Midwestern states.143

Headwater streams are clearly connected to downstream waterways and biological 

communities, and these waters must be equally as protected as perennially-flowing and 

navigable waters. (p. 6-8)

Agency Response: The agencies agree that those features meeting the definition of 

“tributary” in the final rule have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. The final rule categorically considers tributaries, as defined in the rule that 

are not otherwise excluded under paragraph (b) to be waters of the United States.

Lemon Bay Conservancy, Inc. (Doc. #18908.1)

8.161 Your rule proposals explicitly include tributaries and adjacent waters in your jurisdiction 

and we strongly support this inclusion. Even individually small tributaries or adjacent 

wetlands may cumulatively have impacts on total flow.

The discussion accompanying your proposal recognizes this impact to some extent, but it 

tends to talk in terms of pollutants contributed, or blocked, by tributaries or adjacent 

 

140 Id.

141 Pond et al. Downstream effects of mountaintop coal mining: comparing biological conditions using family- and 

genus-level macroinvertebrate bioassessment tools. J. N. Am. Benthol. Soc., 2008, 27(3):717–737. 

http://www.epa.gov/owow/wetlands/pdf/Pond_2008.pdf

142 Nathaniel P. Hitt and Douglas B. Chambers. Temporal changes in taxonomic and functional

diversity of fish assemblages downstream from mountaintop mining Freshwater Science, Vol. 33, No. 3 (September

2014), pp. 915-926. Published by: The University of Chicago Press on behalf of Society for Freshwater Science

http://www.usgs.gov/newsroom/article.asp?ID=3927#.VGYkhvnF98H

143 http://water.usgs.gov/nawqa/sparrow/gulf_findings/ES&T_states.pdf
Clean Water Rule Response to Comments – Topic 8: Tributaries

140

waters. See e.g. 76 F.R. 22194. We urge you to recognize more explicitly the impacts of 

dilution and the mixing of different water sources in changing the downstream 

environment and the desirability of regulating the upstream tributaries and adjacent 

waters to maintain the function of downstream waters. (p. 1)

Agency Response: Section VII of the Technical Support Document discusses the 

science supporting the agencies’ conclusion in regards to tributaries. In addition, 

the Science Report (aka Connectivity Report) discusses tributaries and their 

chemical, physical and biological effects on downstream waters in detail.

Water Environment Federation (Doc. #16584)

8.162 This overly broad definition of tributary could potentially increase the number of manmade conveyances, ditches and conveyance facilities, including those utilized by 

wastewater entities, under federal jurisdiction, and the lack of certainty surrounding the 

rule’s definition of a tributary could lead to regulation of previously unregulated waters. 

This broad classification of “tributaries” would be considered jurisdictional regardless of 

perennial, intermittent or ephemeral flow. Even dry washes could be considered 

jurisdictional under the proposed rule. This is significant for a variety of reasons.

One example of the potential impacts of defining what constitutes a “tributary” too 

broadly is the potential discharge from sanitary sewer systems to dry 

creeks/sloughs/washes when no pollutants ever actually reach water. It is entirely unclear 

whether this constitutes a discharge of pollutants to a water of the U.S. Under the broad 

definition of tributary in the proposed rule, it is possible that spills to dry creeks, sloughs, 

or washes would be considered a “discharge” even if there are no real or potential 

impacts to surface waters of any kind. Similarly, there are circumstances where sewer 

spills occur in a street that drains to a roadside ditch or local creek bed that has no flow 

and is unconnected to a water of the U.S. The responsible party may fully remediate the 

spill and address all real and potential water quality impacts before the spill ever reaches 

a water source. It is difficult to understand how can this kind of circumstance could be 

envisioned as a discharge to “waters of the United States” when there is no actual water 

in a dry creek or ditch nor an adverse impact to the environment. (p. 5-6)

Agency Response: See summary response for Section 8.1. By grounding the 

definition of “tributary” in the final rule to specific physical indicators of flow, the 

agencies believe that confusion regarding whether a feature is a “tributary” or a 

non-jurisdictional “erosional feature” will be minimal. See the summary response 

for Section 8.4, particularly the sub-section titled, “Distinction between an 

ephemeral water and a non-jurisdictional gulley, rill or non-wetland swale.” The 

agencies’ position in regard to tributaries is rooted in a science-based conclusion 

that such waters have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

conclusion. See also Section 9 “Scientific Evidence Supporting the Rule” of the 

Response to Comments. In addition, paragraph (b) of the final rule excludes many 

features from consideration as waters of the United States, including most ditches 

that are not relocated tributaries or excavated in tributaries and stormwater control 

features created in dry land.
Clean Water Rule Response to Comments – Topic 8: Tributaries

141

Congress of the United States, Senate Committee on Environment and Public Works et al. (Doc. 

#16564)

8.163 The proposed "waters of the United States" rule designates "tributaries" as jurisdictional 

per se.144 "Tributary," however, does not mean "a stream feeding a larger stream or a 

lake," as one would understand this term in normal parlance.145 Instead, EPA and the 

Corps have proposed a sweeping definition for "tributary"146:

 Under the proposed rule, "tributary" means "a water physically characterized by 

the presence of a bed and banks and ordinary high water mark [(OHWM)] ... 

which contributes flow, either directly or through another water" to a traditionally 

navigable water (TNW), an interstate water, territorial sea, or impoundment. On 

its face, this definition reaches water features far removed from TNW's and other 

truly national waters. The term's emphasis on mere flow from one water feature to 

a downstream water will bring countless perennial , intermittent, and ephemeral 

streams within the definition of "waters of the United States," and the agencies 

concede as much." (p. 3)

Agency Response: See summary response for section 8.1. 

8.1.1. Relevance of Flow Regime

Agency Summary Response

An extensive number of comments addressed the inclusion of intermittent and ephemeral waters 

in the definition of “tributary.” The proposed rule defined “tributary” as a water physically 

characterized by the presence of a bed and banks and an ordinary high water mark, which 

contributes flow either directly or through another water to a traditional navigable water, and its

preamble indicates that the scientific literature supports a conclusion that waters meeting the 

definition of “tributary,” either individually or in combination have a significant nexus or thus 

are jurisdictional per se. A variety of commenter issues associated with flow regime are 

discussed below.

Issue: Jurisdiction over Intermittent and Ephemeral Waters 

Many commenters indicated that the proposed definition of “tributary” is ambiguous and will 

result in jurisdiction asserted over many additional waters that were not previously jurisdictional, 

particularly intermittent and ephemeral waters. 

The agencies disagree with the assertion that intermittent and ephemeral waters have not been 

jurisdictional previously. CWA jurisdiction historically has been asserted over intermittent and 

ephemeral waters. The longstanding regulatory definition of “waters of the United States” 

 

144 Definition of "Waters of the United States" Under the Clean Water Act, 79 Fed. Reg. 22 188, 22262-22263

(proposed April 21, 20 14) (hereinafter, " Proposed Rule") .

145 See Webster's New Collegiate Dictionary 1238 (Merriam-Webster 1979).

146 See Proposed Rule, 79 Fed. Reg. at 22263.
Clean Water Rule Response to Comments – Topic 8: Tributaries

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included “tributaries” without any limitations regarding volume or duration of flow. The 

December 2008 Guidance on post-Rapanos implementation noted that tributaries that flow only 

in direct response to rainfall are subject to the CWA if they have a significant nexus to a 

downstream traditional navigable water, and that intermittent or seasonal streams were 

jurisdictional without the need for a case-specific showing of significant nexus. Regulations 

addressing water quality standards for waters of the United States provide that states may modify 

standards for streams with natural ephemeral flow but may not declare an ephemeral stream nonjurisdictional altogether. See, e.g., 40 CFR § 131.10(g)(2). Several states and tribes expressly 

cover intermittent and ephemeral waters in their water quality standards submitted to EPA for 

review under the CWA, including Arizona, Delaware, New Mexico, South Carolina, and the Ute 

Mountain Ute Tribe, among others. Federal court decisions, some of which are decades old, 

have supported assertions that intermittent and ephemeral waters are jurisdictional. For example, 

the U.S. District court in Arizona held in 1975 that the definition of waters of the United States 

includes any waterway: “ ... a legal definition of ‘navigable waters’ or ‘waters of the United 

States’ within the scope of the Act includes any waterway within the United States also including 

normally dry arroyos through which water may flow, whether such water will ultimately end up 

in public waters such as a river or stream, tributary to a river or stream, lake, reservoir, bay, gulf, 

sea or ocean either within or adjacent to the United States.” United States v. Phelps Dodge Corp, 

391 F.Supp 1181, 1187 (1975). Practice after Rapanos has considered ephemeral waters as 

jurisdictional under the CWA where they have a significant nexus to a traditional navigable 

water. For example, EPA and the Army Corps of Engineers issued a joint memorandum in 2007 

asserting jurisdiction over a first-order ephemeral stream in Riverside County, California, based 

on its significant nexus to a traditional navigable water. “Assertion of Jurisdiction for 

Jurisdictional Determination SPL-2007-261-FBV” (Dec. 6, 2007), available at: 

http://www.usace.army.mil/Missions/CivilWorks/RegulatoryProgramandPermits/RelatedResour

ces/CWAGuidance.aspx. 

A number of commenters urged the agencies to categorically exclude ephemeral waters, while 

others suggest intermittent and ephemeral waters should not be considered jurisdictional per se

but instead only if a case-by-case analysis indicates a water has a significant nexus. Those 

calling for a categorical exclusion for ephemeral waters noted that ephemeral channels only carry 

surface water immediately after a major rainfall event, and that chemical, physical, and 

biological processes are limited to the short time water is flowing in the channel so there can be 

no significant nexus to downstream waters. Commenters suggesting intermittent and ephemeral 

waters should be subject to a case-by-case significant nexus analysis emphasized that 

characteristics of these waters vary significantly based on adjacent land uses and historic 

activities.

Several commenters stressed that intermittent and ephemeral streams should be protected as 

water of the United States. Several commenters indicated these waters provide habitat for a 

variety of fauna and are important to the watershed even though only flowing during parts of the 

year. Others emphasized that non-perennial streams are more vulnerable to degradation and loss 

because of their size and location, responding quickly to small changes in hydrology and adverse 

water quality impacts. To exclude intermittent and ephemeral tributaries, some commenters 

argued, would greatly narrow the CWA’s jurisdiction and allow serious pollution to accumulate 

during the dry season to legally enter and pollute clean waters during the wet season.
Clean Water Rule Response to Comments – Topic 8: Tributaries

143

The agencies disagree with some commenters’ conclusion that intermittent and ephemeral waters 

cannot have a significant nexus to traditional navigable waters, interstate waters, or territorial 

seas and thus should be excluded per se from jurisdictional consideration. The agencies agree 

with other commenters’ characterization of intermittent and ephemeral waters as having 

significant effects on and, therefore, a significant nexus to the chemical, physical and biological 

integrity of downstream traditional navigable waters provided they meet the rule’s definition of 

“tributary.” For the reasons discussed below, the final rule does not require that a case-by-case 

determination be made regarding whether an ephemeral or tributary stream has a significant 

nexus to navigable waters. Instead, the case-by-case inquiry is whether or not the water under 

consideration meets the rule’s definition of “tributary” and is not excluded by paragraph (b).

The rule’s definition of tributary requires two physical indicators of flow: there must be a bed 

and banks, and an additional indicator of ordinary high water mark. These physical indicators of 

water flow are only created by sufficient and regular intervals of flow. Because the rule’s 

definition of tributary requires these physical indicators, the agencies are not defining “waters of 

the United States” to include all streams that might be considered “tributaries” in the general 

scientific literature. The agencies determined based on their scientific and technical expertise 

that waters meeting the definition of “tributary” in a watershed are similarly situated and have a 

significant nexus alone or in combination with other tributaries, because they significantly affect 

the chemical, physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas. As such, it is appropriate to conclude that intermittent and ephemeral 

waters that meet the definition of tributaries, as defined by the rule, as a category are “waters of 

the United States.” Scientific literature also supports some commenters’ observation that size 

and location of non-perennial streams cause such waters to respond quickly to small changes in 

hydrology and adverse water quality impacts. 

The rule’s conclusion that waters meeting the definition of “tributary” have a significant nexus is 

informed by EPA’s Office of Research and Development (ORD) Science Report, a peerreviewed compilation and analysis of published peer-reviewed scientific literature summarizing 

the current scientific understanding of the connectivity of and mechanisms by which streams and 

wetlands, singly or in combination, affect the chemical, physical, and biological integrity of 

downstream waters. As summarized in the Science Report, scientific literature unequivocally 

demonstrates that tributary streams, individually or cumulatively, exert a strong influence on the 

chemical, physical, and biological integrity of downstream waters. All tributary streams, 

including perennial, intermittent, and ephemeral streams, are chemically, physically, and 

biologically connected to downstream rivers via channels and associated alluvial deposits where 

water and other materials are concentrated, mixed, transformed, and transported. Streams are the 

dominant source of water in most rivers, and the majority of tributaries are perennial, 

intermittent, or ephemeral headwater streams. Headwater streams also convey water into local 

storage compartments such as ponds, shallow aquifers, and floodplains, and into regional and 

alluvial aquifers; these local storage compartments are important sources of water for 

maintaining baseflow in rivers. In addition to water, streams transport sediment, wood, organic 

matter, nutrients, chemical contaminants, and many of the organisms found in rivers. The 

scientific literature provides robust evidence that streams are biologically connected to 

downstream waters by the dispersal and migration of aquatic and semiaquatic organisms, 
Clean Water Rule Response to Comments – Topic 8: Tributaries

144

including fish, amphibians, plants, microorganisms, and invertebrates, that use both upstream 

and downstream habitats during one or more stages of their life cycles, or provide food resources 

to downstream communities. In addition to material transport and biological connectivity, 

ephemeral, intermittent, and perennial flows influence fundamental biogeochemical processes by 

connecting channels and shallow groundwater with other landscape elements. Chemical, 

physical, and biological connections between streams and downstream waters interact via 

integrative processes such as nutrient spiraling. This occurs when stream communities 

assimilate and chemically transform large quantities of nitrogen and other nutrients that, in the 

absence of the above referenced transformations, would be transported directly downstream, 

thereby increasing nutrient loads and associated impairments due to excess nutrients in 

downstream waters. The final Science Report is available at 

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=296414. See also Section 9 “Scientific 

Evidence Supporting the Rule” of the Response to Comments.

The independent EPA Science Advisory Board (SAB) peer reviewed the draft ORD Science 

Report, which was revised and finalized in response to SAB comments. In addition to its peer 

review of the draft ORD Science Report, in a separate effort the SAB also reviewed the 

adequacy of the scientific and technical basis of the proposed rule and provided its advice and 

comments on the proposal in September 2014. The SAB found that the available science 

provides an adequate scientific basis for the key components of the proposed rule. In particular, 

the SAB expressed support for the proposed rule’s inclusion of tributaries as categorical waters 

of the United States. The SAB found “[t]here is strong scientific evidence to support the EPA’s 

proposal to include all tributaries within the jurisdiction of the Clean Water Act. Tributaries, as a 

group, exert strong influence on the physical, chemical, and biological integrity of downstream 

waters, even though the degree of connectivity is a function of variation in the frequency, 

duration, magnitude, predictability, and consequences of physical, chemical, and biological 

process.” The Board advised the agencies to reconsider the definition of tributaries because not 

all tributaries have ordinary high water marks (OHWMs). Examples of tributaries the SAB 

suggested might lack OHWMs but have significant effects downstream include ephemeral 

streams with arid and semi-arid environments or in low gradient landscapes where the flow of 

water is unlikely to cause an OHWM. The SAB also advised the agencies to consider changing 

the wording in the definition to “bed, bank, and other evidence of flow.” SAB 2014a at 2. In 

addition, the SAB suggested that the agencies reconsider whether flow-through lentic systems 

should be included as adjacent waters and wetlands, rather than as tributaries. (The SAB’s final 

letter to the EPA Administrator can be found on the SAB website and in the docket for this rule; 

2014. SAB Consideration of the Adequacy of the Scientific and Technical Basis of the EPA’s 

Proposed Rule titled “Definition of Waters of the United States under the Clean Water Act.” 

EPA-SAB-14-007, U.S. Environmental Protection Agency, Washington, DC). See also Section 9 

“Scientific Evidence Supporting the Rule” of the Response to Comments.

The agencies analyzed the Science Report, SAB comments, and other scientific literature to 

determine which tributaries to traditional navigable waters, interstate waters, or the territorial 

seas have a significant nexus to constitute “waters of the United States” under the Act such that it 

is reasonable to assert CWA jurisdiction over them by rule. As discussed above, the rule’s 

definition of “tributary” requires bed and banks and OHWM as physical indicators of flow, 

which as a result does not include all waters considered tributary in the scientific literature. The 
Clean Water Rule Response to Comments – Topic 8: Tributaries

145

agencies conclude tributaries as defined have a significant impact on the chemical, physical, and 

biological integrity of waters into which they eventually flow— for CWA purposes, traditional 

navigable waters, interstate waters, and the territorial seas. The great majority of covered 

tributaries are headwater streams, and whether they are perennial, intermittent, or ephemeral, 

they play an important role in the transport of water, sediments, organic matter, nutrients, and 

organisms to downstream waters. Covered tributaries serve to store water, thereby reducing 

flooding; provide biogeochemical functions that help maintain water quality; trap and transport 

sediments; transport, store and modify pollutants; provide habitat for plants and animals; and 

sustain the biological productivity of downstream rivers, lakes, and estuaries. Such waters have 

these significant effects whether they are natural, modified, or constructed, as discussed below.

For further discussion, see Final Rule Preamble and the Technical Support Document. See also 

the summary responses in Section 9 “Scientific Evidence Supporting the Rule” of the Response 

to Comments.

The rule’s definition of “tributary” retains many elements from the proposed rule, but reflects 

public comments in several important ways. In particular, the final rule emphasizes the 

importance of flow. The rule definition of “tributary” requires that flow must be of sufficient 

volume, frequency, and duration to create the physical characteristics of bed and banks and an 

OHWM. If a water lacks sufficient flow to create such characteristics, it is not considered 

“tributary” under this rule. To further emphasize this point, the final rule expressly indicates in 

paragraph (b) that ephemeral reaches that do not meet the definition of tributary are not “waters 

of the United States.” The rule includes ephemeral streams that meet the definition of tributary 

as “waters of the United States” because the agencies determined that such streams provide 

important functions for downstream waters, and in combination with other protected tributaries 

in a watershed significantly affect the chemical, physical, and biological integrity of traditional 

navigable waters, interstate waters, and the territorial seas. 

Issue: Legality of Asserting Jurisdiction over Ephemeral Waters

A number of commenters questioned the agencies’ legal ability to assert jurisdiction over 

ephemeral waters. Some observed that Congress did not intend the Clean Water Act (CWA) to 

regulate ephemeral streams, instead limiting the CWA’s jurisdiction to waters and not landscape 

features which can transmit waters such as dry washes, arroyos, and ephemeral streams. Several 

commenters noted that Justice Kennedy’s opinion in Rapanos called for the agencies to identify 

categories of jurisdictional tributaries and the volume of flow and other factors taken into 

consideration. They asserted that considering ephemeral waters as “tributaries” relies on a mere 

hydrologic connection and not the presence of the significant nexus that Justice Kennedy 

indicated was the basis for jurisdiction. Other commenters believed that omission of the 

“relatively permanent” requirement from Justice Scalia’s opinion in Rapanos substantially 

broadens the universe of jurisdictional tributaries, and call for the agencies to incorporate the 

approach in the 2008 Rapanos Guidance, which indicates tributaries that flow after rainfall are 

subject to a case-specific significant nexus analysis. Some commenters asserted that Supreme 

Court precedent requires both the Kennedy and Scalia standards to be met, and only relatively 

permanent waters with a significant impact are protected. 

The final rule concludes that all waters meeting the definition of “tributary” have a significant 
Clean Water Rule Response to Comments – Topic 8: Tributaries

146

nexus, regardless of their flow regime, and thus are considered as per se waters of the United 

States. CWA jurisdiction has historically been asserted over intermittent and ephemeral waters. 

The longstanding regulatory definition of “waters of the United States” included “tributaries” 

without any limitations regarding volume or duration of flow. The December 2008 Guidance on 

post-Rapanos implementation noted that tributaries that flow only in direct response to rainfall 

are subject to the CWA if they have a significant nexus to a downstream traditional navigable 

water, and that intermittent or seasonal streams were jurisdictional without the need for a casespecific showing of significant nexus. Federal court decisions, some of which are decades old, 

have supported assertions that intermittent and ephemeral waters are jurisdictional. See the 

summary response 8.1 above and 8.1.2 below for further discussion about CWA protection of 

ephemeral tributaries. The discussion above summarizes the scientific basis for the rule’s 

conclusion that tributaries, as defined, have a significant nexus and thus are “waters of the 

United States,” including tributaries with ephemeral flow. See the Technical Support document 

for a complete discussion of the legal basis for asserting jurisdiction over ephemeral tributaries, 

section VII including VII.B.vi, and the appropriateness of applying Justice Kennedy’s significant 

nexus standard to tributaries. See also the summary responses in Section 9 “Scientific Evidence 

Supporting the Rule” of the Response to Comments.

Issue: Requirement of “Contribute Flow”

Several commenters raised concerns regarding the element of the “tributary” definition that 

requires that the water “contributes flow, either directly or through another water” to a traditional 

navigable water, interstate water, or the territorial seas. Some recommend the phrase “through 

another water” be struck entirely, while others believe the phrase should be qualified to clarify 

that the flow contribution cannot be through a non-jurisdictional feature. Some expressed 

concern that “another water” was undefined, suggesting the vague term would allow the 

contribution to be through cloud vapor or rain or through groundwater over sixty years. Many 

commenters recommended that a water should be required to contribute flow on a regular basis, 

with a significant flow volume and significant flow duration. Several also expressed concern

that the proposal does not describe methods to quantify contributions of flow as well as 

transmission losses. Some commenters thought that no OHWM is necessary for a water to be 

considered tributary so long as it contributes flow, while others understood that a water can be a 

tributary even if it does not contribute flow so long as it has an OHWM. 

The definition of “tributary” in the final rule retains the phrase “contributes flow, either directly 

or through another water.” This reflects scientific literature about the connectivity among 

waters, discussed earlier. Chapter 2.2 of the ORD Science Report, “An Introduction to River 

Systems” discusses drainage systems that make up a river system and its associated watershed. 

Essentially, in a given watershed, there are many smaller contributing streams (analogous to the 

twigs of a tree), which then are joined together as tributaries and flow into the watershed’s larger 

streams and rivers (the branches and the trunk of the tree). If jurisdictional streams were only 

those streams that themselves flow directly into a traditional navigable water, interstate water, or 

territorial sea, the dendritic nature of the tributary system would make it virtually impossible to 

protect the integrity of downstream waters. The final rule does not require that the flow be 

contributed either directly or through waters that are themselves jurisdictional. Nutrients, 

organic matter, pollutants and biotic drift does not stop at the threshold of a pipe, culvert, ditch, 
Clean Water Rule Response to Comments – Topic 8: Tributaries

147

or swale, and the effect of headwaters on downstream waters is not eliminated by connecting 

through a non-jurisdictional water feature either. Water contributed through non-jurisdictional 

features can have the same impact on the integrity of downstream waters as water contributed 

through jurisdictional waters. For example, a protected tributary with a bed and banks and 

OHWM may flow into a non-wetland swale excluded under paragraph (b) before the flow 

reaches downstream waters. The mere fact that the water flows through the non-jurisdictional 

swale does not sever the significant connection between the upstream protected tributary and the 

downstream water or eliminate the water’s impact downstream; swales can quickly move water 

downstream, transporting sediment, nutrients, and other materials downstream. Note that a nonjurisdictional feature contributing a tributary’s flow does not itself become jurisdictional as a 

result. The preamble to the final rule, as did the proposed rule, includes language clarifying the 

terms water and waterbody as they are used in the rule. Groundwater and atmospheric moisture 

are not waters. For discussion of the term “through another water” also see the Technical 

Support Document Section VII.

The final rule definition makes clear that a water is considered tributary if (1) it contributes flow, 

either directly or through another water, to a traditional navigable water, interstate water, or the 

territorial seas, and (2) the water has the physical indicators of a bed and banks and an ordinary 

high water mark (OHWM). Where the water flows through another water, that other water need 

not itself be jurisdictional. The physical indicators of bed, banks, and an OHWM demonstrate 

there is sufficient volume, frequency and duration of flow to significantly affect downstream 

waters and thus to qualify as a tributary. This definition should clarify commenters’ 

misunderstandings that only OHWM or only flow are sufficient for a water to be considered a 

tributary under the final rule. It also clarifies that any flow sufficient to create these physical 

indicators has enough flow to be considered a tributary.

Determinations of whether a water “contributes flow” are expected to be done in a manner 

similar to what has been practiced in the field for decades. While precise measurements of flow 

volume and duration are not required, tools such as aerial photographs, topographic maps, flow 

gauges, and the like will be helpful in determining contribution of flow. The final rule preamble 

discusses this process in greater length in Section IV(F).

Issue: Regulation of Man-Altered Streams

Some commenters objected to the proposed definition of “tributary” including manmade 

features, arguing protection is wasteful for such features. They think that asserting jurisdiction 

over constructed and modified canals, ditches, culverts, and similar waters is an expansion of 

jurisdiction to waters that were not previously regulated. Several commenters suggested that the 

rule expressly exclude all constructed waters from the definition of “waters of the United States.” 

While the rule does exclude several types of constructed waters from jurisdiction, it continues 

existing practices which consider constructed tributaries as jurisdictional unless expressly 

excluded in paragraph (b) for the reasons described in the final rule preamble, and in the 

Technical Support Document. The agencies also note that current practice regulates many 

modified and constructed features as waters of the United States, and therefore disagree with 

some commenters’ assertions that asserting jurisdiction over constructed or modified water 

features is an expansion of CWA regulation. For example, under the 2008 Rapanos Guidance 
Clean Water Rule Response to Comments – Topic 8: Tributaries

148

ditches have been considered jurisdictional where they contribute flow to the tributary system 

and have at least seasonal flow or are not excavated in uplands. 

The final rule does not distinguish among natural, modified, and constructed features in the 

definition of “tributary.” If a water meets the definition of “tributary” and is not excluded under 

paragraph (b), the water is considered jurisdictional. The rationale for this approach is based on 

the fact that modified and constructed tributaries perform many of the same functions as natural 

tributaries, especially the conveyance of water that carries nutrients, pollutants, and other 

constituents, both good and bad, to traditional navigable waters, interstate waters, and the 

territorial seas. The scientific literature recognizes that features that convey water, whether they 

are natural, modified, or constructed, provide substantial connectivity between streams and 

downstream waters. For example, scientific studies have documented how ditches quickly move 

water downstream due to their often straightened and channelized nature, transporting 

downstream sediment, nutrients, and other materials. Studies have explored how ditches used to 

drain agricultural fields to stream networks serve as conveyances for nutrients, sediment, and 

contaminants. Similarly, data from the Baltimore Ecosystem Study Long-Term Ecological 

Research site suggest that increased hydrologic connectivity from urban infrastructure (e.g., 

pipes, storm drains, ditches) in headwaters increases the frequencies of occurrence and transport 

rates of nutrients, carbon, and metals to downstream surface waters. Modified and constructed 

tributaries also provide corridors for movement of organisms between headwaters and traditional 

navigable waters, interstate waters, and the territorial seas. The important effect – and thus the 

significant nexus – between a tributary and a traditional navigable water, interstate water, and the 

territorial sea is not broken where the tributary flows through a culvert or other structure. The 

effects of altered streams and man-made features is discussed further in the ORD Science

Report, particularly in Section 2.4.4. See also the TSD section VII and the summary responses 

in Section 9 “Scientific Evidence Supporting the Rule” of the Response to Comments.

Issue: Definitions and Clarity

Numerous commenters asked that the final rule define terms related to the definition of 

“tributary,” to increase clarity and make implementation easier. In response, the final rule 

preamble includes definitions of bed and banks, perennial, intermittent, and ephemeral, adapted 

largely from longstanding agencies’ practice as well as public comments. Several commenters 

suggested that the rule should add a definition of “ordinary high water mark.” The rule adds the 

Corps’ existing regulatory OHWM definition to EPA’s regulations, and the preamble notes that 

several Corps technical manuals are available to help identify OHWM. For a discussion of the 

agencies’ response to comments regarding clarity for definitions, see Compendium 14.3 and 

associated summary essay and individual responses.

Specific Comments:

Tennessee Valley Association (Doc. #17470)

8.164 b. Develop a More Focused Definition of Tributaries

TVA supports development of a bright line definition of tributaries that includes 

perennial and intermittent streams as jurisdictional. It is our opinion that such streams 

should receive a higher level of protection than ephemeral streams and wet weather 

conveyances. A focused definition of tributaries should be based on the frequency and 
Clean Water Rule Response to Comments – Topic 8: Tributaries

149

duration of flow as well as a defined proximity to traditional navigable waters. It should 

also categorically exclude as jurisdictional ephemeral streams, wet weather conveyances, 

and ditches. (p. 8)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters.

8.165 c. Provide Alternative Protection for Minor Watercourses

In order to provide an adequate level of protection for minor watercourses, EPA could 

develop a defined hydrologic determination process for those watercourses that flow only 

in direct response to precipitation runoff in their immediate locality, whose channels are 

at all times above the ground water table, that are not suitable for drinking water supplies, 

and in which due to naturally occurring ephemeral or low flow there is not sufficient 

water to support fish, or multiple populations of obligate lotic aquatic organisms whose 

life cycle includes an aquatic phase of at least two months. These can be covered with a 

more streamlined and efficient general permit process such as that currently employed by 

the Tennessee Department of Environment and Conservation (TDEC). TVA believes that 

the current TDEC Aquatic Resource Alteration rule and associated permitting process is 

appropriately protective of aquatic resources and has proven efficient and effective over 

the last several years. See http://www.tn.gov/sos/rules/0400/0400-40/0400-40-

07.20131216.pdf for details. (p. 8)

Agency Response: EPA appreciates the commenter’s suggestion about providing 

alternative protection levels for “minor watercourses.” We are not sure what the 

commenter means by “a defined hydrologic determination process.” For an 

explanation of the agencies definition of “tributary,” see preamble, TSD and 

summary response for “Relevance of Flow Regime” above, particularly subsection 

on jurisdiction over intermittent and ephemeral waters. The agencies note that the 

CWA authorizes general permits under sections 402 and 404 for discharges that 

have only minimal impacts individually and cumulatively, and that such general 

permits are helpful to streamline administrative processes. However, permit 

requirements apply only to discharges into waters of the U.S.

Pueblo of Sandia (Doc. #2729)

8.166 The Pueblo supports the defining of all tributaries as "waters of the US". As you are 

aware headwater streams provide most of the flow to downstream waters and are a major 

supply of public drinking water systems. These clean water supplies are crucial to local 

areas, especially Albuquerque, New Mexico which uses surface water from the San JuanChama Rivers in Northern New Mexico. Intermittent and ephemeral streams are equally 

important. Although they may flow only during parts of the year they provide habitat for 

a variety of fauna and are important to the watershed. (p. 2)

Agency Response: See summary response for 8.1 and “Relevance of Flow 

Regime” above, particularly subsection on jurisdiction over intermittent and 

ephemeral waters.
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Rebekah Warren, Michigan State Senator, 18th District (Doc. #4769)

8.167 As you know, wetlands and small streams, including those that flow only seasonally, 

have a direct impact on the health and quality of larger streams and rivers downstream. 

Not only are these resources critical drinking water sources, they also protect 

communities from flooding and filter pollutants. (p. 1)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsection on jurisdiction over intermittent and ephemeral waters. 

Pennsylvania Fish and Boat Commission (Doc. #4826)

8.168 Within the tributary language section in the proposed rule, the agencies introduced the 

term "distant headwaters". In Part II: Additional Scientific Support, the agencies provide 

evidence for the importance of tributaries and indicate that, "distant headwaters with 

stronger connections to groundwater or consistently higher precipitation levels than 

downstream reaches contribute more water to downstream rivers". The proposed rule also 

indicates that, "to understand the health, behavior and sustainability of downstream 

waters, the effects of small waterbodies in a watershed need to be considered in 

aggregate". In Pennsylvania, the Ridge and Valley Ecoregion supports small first order 

tributaries with their genesis on a ridge with continued stream flow toward the valley 

floor. Many of these streams flow into a sinkhole or other opening in the landscape and, 

not having a distinguishable significant nexus to a traditional navigable water, interstate 

water or territorial sea, enter the groundwater and arise as springs in the downstream 

watershed. Geological formations, (e.g., sandstone ridges and limestone/dolomitic 

valleys) are often the landscape features that create this flow pattern. In the Ridge and 

Valley Ecoregion, these flow patterns are common and provide significant biological, 

physical and chemical benefits to the watershed. The PFBC strongly recommends that the 

agencies consider these "distant headwaters" or tributary waters as jurisdictional within 

the CWA definition of "waters of the United States." (p. 2)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

on requirement of “contribute flow.” See also summary 8.3 on breaks in OHWM. 

New York State Attorney General Office et al. (Doc. #6020.1)

8.169 First, the proposed rule is grounded in peer-reviewed scientific studies that confirm 

fundamental hydrologic principles. Water flows downhill, and connected waters, singly 

and in the aggregate, transport physical, chemical and biological pollution that affects the 

function and condition of downstream waters, as demonstrated by the many studies on 

which EPA and the Corps rely. The health and integrity of watersheds, with their 

networks of tributaries and wetlands that feed downstream waters, depend upon 

protecting the quality of upstream headwaters and adjacent wetlands. Comprehensive 

coverage under the CWA of these ecologically connected waters is essential to achieve 

the water quality protection purpose of the act. (p. 2)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

on requirement of “contribute flow.”
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Quapaw Tribe of Oklahoma (the O-Gah-Pah) (Doc. #7980)

8.170 3. Seasonal Tributaries. Existing regulations require establishment of a significant nexus 

for tributaries that flow less than seasonally (typ. 90 continuous days in a year). In 

practice, the USACE has regularly determined that many remote ephemeral drainages are 

not Waters of the U.S. The proposed rule will bring most, if not all, of these tributaries 

into the scope of jurisdictional Waters of the U.S. This would eliminate the USACE's 

flexibility in making individual determinations based on site-specific conditions. (p. 2)

Agency Response: See summary response for “Relevance of Flow Regime” above. 

The commenter is correct that the December 2008 guidance calls for a significant 

nexus evaluation for tributaries that are not relatively permanent, i.e., flow less than 

seasonally. Existing regulations do not require a significant nexus evaluation for 

any waters; one of the reasons for this rulemaking is to ensure current regulations 

reflect the 2006 Rapanos decision and 2001 SWANCC decision. In Rapanos, Justice 

Kennedy noted that the agencies could through regulations or adjudication identify 

categories of waters that have a significant nexus either individually or in 

combination, which would support an assertion of jurisdiction over the categories 

without the need for a case-specific significant nexus determination. See Rapanos at 

781. The agencies are making such a categorical determination for waters that 

meet the rule’s definition of “tributary.”

Navajo Nation Environmental Protection Agency (Doc. #10117)

8.171 The Navajo Nation EPA Water Quality Program agrees with and supports the proposed 

definition of "tributary" because, as explained in the proposal, it recognizes that "the flow 

in the tributary may be ephemeral, intermittent or perennial, but the tributary must drain, 

or be part of a network of tributaries that drain, into an (a)(1) through (a)(4) water under 

today 's proposed rule." 79 Fed. Reg. at 22202. This definition recognizes that when 

surface flow in ephemeral waters ceases, subsurface flow still may exist and may 

transport pollutants into downstream water bodies. Subsurface transport of pollutants in 

ephemeral water bodies into downstream receiving water bodies is a predominant 

condition in the arid southwest, including in the Navajo Nation. (p. 2-3)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

on requirement of “contribute flow.” While shallow subsurface pollutant transport 

can have an important impact on the integrity of downstream traditional navigable 

waters, interstate waters, and the territorial seas, the agencies note that shallow 

subsurface water itself is not a water of the U.S. Paragraph (b) of the rule provides 

that groundwater is excluded from the definition of waters of the U.S. because 

numerous courts have held that the CWA is a surface water statute. See also 

summary response 8.3 below on breaks in OHWM. 

Washington State Senate (Doc. #10871)

8.172 ...[W]e support the agencies' proposal to include tributary streams and wetlands that are 

seasonal, intermittent, or ephemeral where they have a "significant nexus" to traditional 

navigable water, interstate water, or the territorial seas. We understand that in most cases 

involving such streams, the determination of whether the nexus is "significant" will turn 
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152

on a case-by-case determination of whether the stream or wetland significantly affects the 

chemical, physical, or biological integrity of navigable water. (p. 1)

Agency Response: See summary response for “Relevance of Flow Regime” above. 

The proposed and final rules categorically assert jurisdiction over waters meeting 

the rule’s definition of “tributary.” As a result, the commenter’s understanding is 

incorrect to the extent it thinks that the rule requires a case-by-case determination 

on whether a tributary stream has a significant nexus. Instead, the case-by-case 

question is whether or not the water under consideration meets the rule’s definition 

of tributary and is not excluded by paragraph (b).

8.173 Your agencies will likely receive negative comments from some other Washington State 

legislators about the proposed "continuously flowing" standard, arguing that it would 

exacerbate the Act's enforcement problems by exposing routine acts such as land 

preparation for residential development or farming to enforcement under the Act, which 

they might contend has no apparent connection to water pollution. They are likely to 

contend that the "significant nexus" standard is not clear and will be applied 

inconsistently by the agencies.

We strongly disagree with these arguments. We believe the proposed rule does an 

excellent job of providing clear standards for determining the jurisdictional application of 

the Act to seasonal, intermittent and ephemeral streams and wetlands. The rule properly 

requires a significant connection to downstream traditional navigable waters, a 

connection that significantly affects the downstream water's chemical, physical or 

biological integrity. To exclude these tributary streams because they are not 

"continuously flowing" would greatly narrow the Act's jurisdiction, which we believe is 

the principal goal of those advocating for such a standard, rather than achieving a clearer 

standard for enforcement purposes.

It would allow serious pollution accumulating during the dry season to legally enter and 

pollute clean waters during the wet season. For example, much of the state of Washington 

receives relatively little precipitation during several months of the year, with seasonal 

streams becoming dry streambeds and swales. At the same time we are experiencing 

unprecedented shipments of petroleum by rail crossing dozens of these "dry" streambeds, 

with any leaks or larger releases from these shipments into these areas inevitably destined 

to be washed down-gradient into our state's navigable waters. (p. 2)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters.

District Department of the Environment, Government of the District of Columbia (Doc. 

#12716.1)

8.174 ...the District requests clarification of the proposed rule's definition of the term 

"tributary" to ensure that the proposed rule does not have unintended consequences for 

urban jurisdictions. Specifically, was EPA's intent to include piped sections of streams in 

its definition of "tributary," and therefore consider those sections "waters of the United 

States"? The District suggests amending the proposed rule to clarify that while a tributary 

may have piped or buried sections incorporated into a storm sewer system, the 
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153

designation of "waters of the United States" should extend only to the day-lit sections of 

the tributary. (p. 1)

Agency Response: Streams with a break in OHWM can be WOUS under current 

practice (2008 Rapanos Guidance, including the currently used Approved 

Jurisdictional Determination Form, which states, “A natural or man-made 

discontinuity in the OHWM does not necessarily sever jurisdiction (e.g., where the 

stream temporarily flows underground, or where the OHWM has been removed by 

development or agricultural practices). Where there is a break in the OHWM that 

is unrelated to the waterbody’s flow regime (e.g., flow over a rock outcrop or 

through a culvert), the agencies will look for indicators of flow above and below the 

break,” (footnote 6 page 3). The final rule states: “A water that otherwise qualifies 

as a tributary under this definition does not lose its status as a tributary if, for any 

length, there are one or more man-made breaks (such as bridges, culverts, pipes, or 

dams), or one or more natural breaks (such as wetlands at the head of or along the 

run of a stream, debris piles, boulder fields, or a stream that flows underground) so 

long as a bed and banks and an ordinary high water mark can be identified 

upstream of the break.” However, the final rule also includes an exclusion at 

paragraph (b) for stormwater control features constructed in dry land. 

Virginia Department of Transportation (Doc. #12756)

8.175 VDOT is concerned that the Proposed Rule goes too far with respect to claiming 

jurisdiction over tributaries.... The current definitions of 'Tributary' ... provided in the 

proposed rule could be interpreted by federal staff to allow more ambiguity and result in 

agencies claiming jurisdiction over many additional waters that were not previously 

jurisdictional. For example, the definition of 'Tributary' implies that nearly every channel 

will now be jurisdictional up to the headwaters. We agree that this measure would save 

time in that fewer significant nexus determinations would need to be completed by 

applicants and agencies could reduce review time in preparing jurisdictional 

determinations. However, such rulings would needlessly result in more jurisdictional 

surface water features identified in project study areas, more project impacts, more 

mitigation required and possibly more complicated permitting strategies that will result in 

more time, effort and money spent to authorize project impacts in those areas. This level 

of effort is wasteful for a manmade feature that truly should not be considered 

jurisdictional. (p. 5)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

on requirement of “contribute flow.” The final rule, like the proposed rule, 

establishes categorical jurisdiction over all waters that meet the definition of 

“tributary” and that are not excluded in paragraph (b). This position is rooted in a 

science-based conclusion that such waters have a significant nexus either 

individually or in the aggregate with traditional navigable waters, interstate waters, 

and the territorial seas. Section VII of the Technical Support Document discusses 

the science supporting the agencies’ conclusion.
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154

Texas Department of Transportation (Doc. #12757)

8.176 ...the 2008 Guidance deemed tributaries as jurisdictional by rule- that it, without the need 

for a significant-nexus determination- only when the tributaries "are relatively permanent 

where the tributaries typically flow year-round or have continuous flow at least 

seasonally (e.g., typically three months)." That guidance also specifically noted that 

"relatively permanent" waters "do not include ephemeral tributaries which flow only in 

response to precipitation and intermittent streams which do not typically flow year-round 

or have continuous flow at least seasonally.

The omission of the "relatively permanent" requirement would substantially broaden the 

universe of tributaries deemed jurisdictional by rule. In effect, a tributary would be 

deemed jurisdictional by rule without any consideration of the flow regime in that 

tributary. A stream with intermittent or even ephemeral flow could be found 

jurisdictional by rule, simply because it has an indirect, infrequent downstream 

connection to a jurisdictional water. We believe this approach is inconsistent with the 

intent of the proposed to clarify, not expand, the scope of jurisdiction under the Clean 

Water Act.

Recommendation: We recommend revising modifying the proposal rule to ensure that 

tributaries are evaluated under the same criteria used in the 2008 Guidance: tributaries 

should be deemed jurisdictional by rule only if they have a "relatively permanent flow" 

(or an equivalent requirement, such as "perennial flow"), meaning that they "typically 

flow year-round or have continuous flow at least seasonally (e.g., typically three 

months)." (p. 3)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters. 

The final rule, like the proposed rule, establishes categorical jurisdiction over all 

waters that meet the definition of “tributary” and that are not excluded in 

paragraph (b). Compared to the historic scope of the existing rule, the final rule is 

narrower; compared to agency practice in light of guidance issued after SWANCC 

and Rapanos, the final rule is generally broader, but not broader than the prior 

regulatory definition. The agencies’ position in regard to tributaries is rooted in a 

science-based conclusion that such waters have a significant nexus either 

individually or in the aggregate with traditional navigable waters, interstate waters, 

and the territorial seas. Section VII of the Technical Support Document discusses 

the science supporting the agencies’ conclusion.

New Mexico Department of Agriculture (Doc. #13024)

8.177 Previously, paragraph (s)(5) states that EPA will assert jurisdiction over "tributaries of 

waters identified in paragraphs (s)( 1) through (4)." However, this paragraph depicts a 

much broader jurisdictional reach because of the definition of the term tributary in (u)(5).

Due to the qualifier "or through another water," NMDA notes that waters may pass 

through nonjurisdictional waters and still be classified as tributaries. This is because the 

term another water is not defined hence may refer to non jurisdictional water. This is true 

especially when another water is contrasted with a "water that contributes flow directly" 

to a jurisdictional water.
Clean Water Rule Response to Comments – Topic 8: Tributaries

155

We recommend striking the qualifier "or through another water," and leaving the 

wording, "The term tributary means a water physically characterized by the presence of a 

bed and banks and ordinary high water mark, as defined at 33 eFR 328.3 (e), which 

contributes flow directly to a water identified in paragraphs (s)(1) through (4) of this 

section. " (p. 13)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsection on the requirement of “contribute flow.” The final rule does 

not require that the flow be contributed either directly or through waters that are 

themselves jurisdictional. Waters contributed through non-jurisdictional features 

can have the same impact on the integrity of downstream waters as water 

contributed through jurisdictional waters. The agencies maintain that some waters 

may pass through non-jurisdictional waters, such as excluded ditches, but will still 

be classified as tributaries both upstream and downstream of the non-jurisdictional 

feature. 

8.178 Tributary (u) (5) (page 11 -12)

Due to the qualifier "or through another water," NMDA notes that waters may pass 

through nonjurisdictional waters and still be classified as tributaries. This qualifier should 

be removed from the definition. (p. 27)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsection on the requirement of “contribute flow.” The final rule does 

not require that the flow be contributed either directly or through waters that are 

themselves jurisdictional. Waters contributed through non-jurisdictional features 

can have the same impact on the integrity of downstream waters as water 

contributed through jurisdictional waters. The agencies maintain that some waters 

may pass through non-jurisdictional waters, such as excluded ditches, but will still 

be classified as tributaries both upstream and downstream of the non-jurisdictional 

feature.

State of Wyoming (Doc. #14584)

8.179 The Agencies' proposed definition of tributaries is flawed. It includes any geomorphic 

feature capable of carrying water (if it can physically be characterized as having a bed, 

banks and ordinary high water marks) that contributes flow either directly or through 

another water. It is overbroad, ambiguous and greatly expands federal jurisdiction beyond 

the scope of the Act. It incorporates dry washes, arroyos, seasonal water bodies, and 

ephemeral streams (that rarely have sufficient flow and volume to significantly affect 

more permanent water bodies). Congress clearly intended to limit the Act's jurisdiction to 

waters- not to landscape features which can transmit waters or lands which can affect 

waters.

The Agencies have ignored the Supreme Court's plurality decision on the need for 

relatively permanent, standing, or continually flowing bodies of water. The proposed 

definition of a tributary and the intent to federally regulate tributaries must be 

reconsidered. Only waters with significant and measureable flows and relatively 

permanent, continual hydrologic connections to navigable or interstate waters should be 

included. This would be consistent with Justice Kennedy's assessment that there must be 
Clean Water Rule Response to Comments – Topic 8: Tributaries

156

"some measure of the significance of the connection for downstream water quality." 547 

U.S. at 784-785. (p. 4)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

the legality of asserting jurisdiction over ephemeral waters. Section I of the 

Technical Support Document further discusses the legal basis of the final rule, 

including consistency with the statute and Supreme Court decisions.

8.180 Justice Kennedy stated that the Agencies could, through rulemaking, "identify categories 

of tributaries" that were jurisdictional. 547 U.S. at 781. He specifically identified 

"volume of flow," "proximity" and "other relevant considerations" as factors on which to 

base and limit the categories. Id. The Agencies have disregarded both the plurality and 

Justice Kennedy in their attempt to expand the definition of tributary to include 

everything. (p. 5)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

the legality of asserting jurisdiction over ephemeral waters. Section I of the 

Technical Support Document further discusses the legal basis of the final rule, 

including consistency with the statute and Supreme Court decisions. The agencies’ 

position in regard to tributaries is rooted in a science-based conclusion that such 

waters have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

conclusion.

8.181 The Agencies should establish not if there is a connection but rather at what level waters 

become relatively permanent or continually flowing bodies that contribute significantly to 

interstate or navigable streams. They should then develop appropriate categories leaving 

significant room for the states. Given the science, the Agencies are derelict in failing to 

propose alternative, quantifiable, and objective measures. The Agencies should withdraw 

the current proposal and work instead on a quantifiable, standards-based approach, like 

that suggested by Justice Kennedy. (p. 5)

Agency Response: Section I of the Technical Support Document discusses the 

legal basis of the final rule, including consistency with the statute and Supreme 

Court decisions. The agencies’ conclusions that certain categories of waters are 

jurisdictional are not based on an “any connection” theory; instead they are based 

on careful examinations of the science and the law to conclude that particular 

categories of waters significantly affect the chemical, physical, and biological 

integrity of a traditional navigable water, interstate water, or the territorial seas. 

The agencies’ position in regard to tributaries is rooted in a science-based 

conclusion that such waters have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion. 
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157

North Carolina Department of Agriculture and Consumer Services (Doc. #14747)

8.182 The new definition of "tributary" does not exclude ephemeral water bodies (features 

which contain water only after a precipitation event). Therefore, ephemeral streams or 

water bodies that contain a bed and bank and an ordinary high water mark will be subject 

to jurisdiction. 

NCDA&CS opposes the language of the proposed rule that makes ephemera l streams 

and water bodies subject to jurisdiction. This was clearly not the intent of Congress or the 

Supreme Court. CWA jurisdiction should be limited to water bodies that are permanent 

or relatively permanent. Ephemeral streams clearly do not meet this standard. One 

particular concern of NCDA&CS is grassed waterways. Under no circumstances should 

grassed waterways, which are a widely recognized conservation practice, be considered 

jurisdictional. (p. 3)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

the legality of asserting jurisdiction over ephemeral waters. Section I of the 

Technical Support Document discusses the legal basis of the final rule, including 

consistency with the statute and Supreme Court decisions. The agencies’ position in 

regard to tributaries is rooted in a science-based conclusion that such waters have a 

significant nexus either individually or in the aggregate with traditional navigable 

waters, interstate waters, and the territorial seas. Section VII of the Technical 

Support Document discusses the science supporting the agencies’ conclusion. 

Grassed waterways are excluded under paragraph (b)(4) of the final rule and are 

therefore not considered waters of the United States.

Office of the Governor, State of Kansas (Doc. #14794)

8.183 Kansas acknowledges that some ephemeral streams may actually be significant 

contributors affecting the conditions of downstream waters. Therefore, we believe such 

streams should not be dealt as tributaries as outlined in the proposed rule but viewed by 

the Federal agencies as "other waters". That approach requires case-by-case 

determinations, which is an appropriate evaluation for ephemeral streams. This analysis 

does add to the work burden of Federal staff, but correct jurisdictional determinations 

demand such an investment. Under the proposed rule, Federal expenditure of resources 

and energy will be forthcoming as necessary in rebutting appeals of the automatic 

inclusion of all tributaries as jurisdictional. Kansas believes the citizens of the State are 

better served when determinations are done upfront in light of all available data pertinent 

to the issue at hand. State agency personnel have the knowledge, background and 

experience in assisting the Federal agencies in jurisdictional determinations with these 

specific "other waters". The interaction of Federal and State personnel better advances 

cooperative Federalism than the blanket application of the Clean Water Act envisioned 

under the proposed rule. As a backstop, many of the waters found not to be jurisdictional 

are protected, where warranted, by State authorities applied to waters of the State. As 

stated previously, the watershed orientation of programs, such as the Kansas TMDL 

program, applies corrective actions to any contributing sources within that watershed, 

regardless if they lie on classified or unclassified waters. (p. 6)
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158

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

the legality of asserting jurisdiction over ephemeral waters. The agencies’ position 

in regard to tributaries is rooted in a science-based conclusion that such waters have

a significant nexus either individually or in the aggregate with traditional navigable 

waters, interstate waters, and the territorial seas. Section VII of the Technical 

Support Document discusses the science supporting the agencies’ conclusion.

San Carlos Apache Tribe (Doc. #15067)

8.184 Existing regulations require establishment of a significant nexus for tributaries that flow 

less than seasonally. In practice, the EPA has regularly determined that remote ephemeral 

drainages are not waters of the U.S. The proposed rule will bring most, if not all, of these 

drainages into the scope of the jurisdictional waters of the U.S. This would eliminate the 

flexibility in making individual determinations based on site-specific conditions. 

... The proposed rule is overly broad, subjective and, frankly, illogical. The proposed rule 

makes no mention of objective, measurable features such as flow volume, seasonality, 

duration of flow, or distance to a navigable water. Instead, all that seems to be required 

for even the slightest and most occasional ephemeral drainage feature to be a covered 

“tributary” is a discernible high water mark and either a bed or a bank. Despite the 

contention that the rule promotes “transparency, predictability, and consistency” (77 F.R. 

at 22190), it will not. (p. 5)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsection on jurisdiction over intermittent and ephemeral waters. The 

agencies’ position in regard to tributaries is rooted in a science-based conclusion

that such waters have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

conclusion.

Georgia Environmental Protection Division (Doc. #16348)

8.185 The term "tributary" does not just include streams. The proposed definition of tributaries 

includes the presence of a bank, a bed, and an ordinary high water mark but has no 

reference to flow. All intermittent and some ephemeral tributaries would therefore be 

jurisdictional and not subject to case-by-case analysis. (p. 1)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsection on jurisdiction over intermittent and ephemeral waters. The 

agencies’ position in regard to tributaries is rooted in a science-based conclusion

that such waters have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

conclusion.
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159

Attorney General, State of Michigan (Doc. #16469)

8.186 Under the proposed rule, all tributaries are categorically determined to have a significant 

nexus to core waters, and are "Water of the United States" subject to federal jurisdiction. 

But it is far from clear that there is a legal or scientific justification for categorical federal 

regulation of an area as a tributary when it does not have any visible evidence that water 

remains in the area for any period of time. Further, it is unclear what it means for an area 

to "contribute flow" to a core water. If any amount of water flows over an area, and some 

of that water ultimately reaches a core water, does that "contribute flow"? Is that 

sufficient to create a per se significant nexus with core waters? And how is a farmer or 

other landowner to know that they have an area that "contributes flow" to a core water 

when it has no physical indicators of that water? I concur with Michigan Farm Bureau 

that none of these questions have been adequately answered. (p. 5)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters, the 

legality of asserting jurisdiction over ephemeral waters and the requirement of 

“contribute flow.” Section I of the Technical Support Document discusses the legal 

basis of the final rule, including consistency with the statute and Supreme Court 

decisions. The agencies’ position in regard to tributaries is rooted in a science-based 

conclusion that such waters have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion. No feature that lacks the physical indicators of 

bed and bank and an OHWM will be jurisdictional as tributaries. 

Tennessee Department of Transportation (Doc. #16470)

8.187 The proposed rule defines tributaries of certain other waters as jurisdictional by rule and 

includes a new definition of "tributary." TDOT agrees with the concept of defining 

certain tributaries as jurisdictional by rule. TDOT also agrees that it is appropriate and 

useful to include a definition of the term "tributary" in the regulations. However, TDOT 

is concerned that the proposed rule would, in effect, substantially broaden the universe of 

tributaries that are deemed jurisdictional by rule. In as much, TDOT recommends 

revising the rule to be more consistent with the treatment of tributaries in the 2008 

Guidance.

A. "Reasonably permanent flow"

The proposed rule defines "tributary" without any reference to the frequency or extent of 

flow. Tributaries are defined to include any water that is "physically characterized by the 

presence of a bed and banks and ordinary high water mark" and that "contributes flow, 

either directly or through another water, to a water identified in paragraphs (a)( 1) 

through (4) of this section." (79 Fed. Reg. 22263). If a water meets these criteria, it is 

jurisdictional by rule.

By contrast, the 2008 Guidance (p. 6) deemed tributaries as jurisdictional by rule - that it, 

without the need for a significant-nexus determination - only when the tributaries "are 

relatively permanent where the tributaries typically flow year-round or have continuous 

flow at least seasonally (e .g., typically three months) ." That guidance also specifically 
Clean Water Rule Response to Comments – Topic 8: Tributaries

160

noted that "relatively permanent" waters "do not include ephemeral tributaries which 

flow only in response to precipitation and intermittent streams which do not typically 

flow year- round or have continuous flow at least seasonally.

The omission of the "relatively permanent" requirement would substantially broaden the 

universe of tributaries deemed jurisdictional by rule. In effect, a tributary would be 

deemed jurisdictional by rule without any consideration of the flow regime in that 

tributary. A stream with intermittent or even ephemeral flow could be found 

jurisdictional by rule, simply because it has an indirect, infrequent downstream 

connection to a jurisdictional water. TDOT believes this approach would expand, not 

clarify, the scope of the federal jurisdiction under the Clean Water Act.

TDOT recommends modifying the proposal rule to ensure that tributaries are evaluated 

under the same criteria used in the 2008 Guidance: tributaries should be deemed 

jurisdictional by rule only if they have a "relatively permanent flow" (or an equivalent 

requirement, such as "perennial flow"), meaning that they "typically flow year-round or 

have continuous flow at least seasonally (e .g., typically three months)." If relatively 

permanent flow is not found, the tributary still could be evaluated under the significant 

nexus test , as was the case under the 2008 Guidance.

B. "Do not contribute flow, either directly or through another water"

As discussed above in the context of the ditch exclusions, TDOT is concerned that the 

phrase "contributes flow, either directly or through another water" could be interpreted 

very broadly, so that it encompasses waters that have a highly remote or tenuous 

downstream connection to other jurisdictional waters.

As noted above, TDOT recommends clarifying that a tributary does not "contribute flow 

"to another water if its only connection to that water is "insubstantial or remote." TDOT 

recommends making this change regardless of whether the definition is modified to 

include a requirement for "relatively permanent" flow. (p. 4-5)

Agency Response: Compared to the historic scope of the existing rule, the final 

rule is narrower; compared to agency practice in light of guidance issued after 

SWANCC and Rapanos, the final rule is generally broader, but not broader than 

the prior regulatory definition. See summary response for “Relevance of Flow 

Regime” above, particularly subsections on jurisdiction over intermittent and 

ephemeral waters and the requirement of “contribute flow.” The final rule, like the 

proposed rule, establishes categorical jurisdiction over all waters that meet the 

definition of “tributary” and that are not excluded in paragraph (b). This position 

is rooted in a science-based conclusion that such waters have a significant nexus 

either individually or in the aggregate with traditional navigable waters, interstate 

waters, and the territorial seas. Section VII of the Technical Support Document 

discusses the science supporting the agencies’ conclusion.

Department of Health and Environmental Control, State of South Carolina (Doc. #16491)

8.188 It is immediately clear that this definition is broader, than the Agencies' current practice 

in accordance with the post-Rapanos guidance which calls for relatively permanent 

tributaries to be categorically jurisdictional, but requires a case by case analysis for 

tributaries that are not relatively permanent. ,
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161

In the Proposed Rule, the Agencies explain that their assessment of hundreds of peerreviewed scientific studies have led to the conclusion that all tributaries have a significant 

nexus to downstream navigable waters, Hence, for the new definition, flow permanence 

does not matter. Instead any flow is enough to make a tributary jurisdictional provided it 

conforms to the other features.

SCDHEC is concerned that this represents a departure from current practices and is 

another means by which the Agencies are asserting jurisdiction more broadly. (p. 3)

Agency Response: Compared to the historic scope of the existing rule, the final 

rule is narrower; compared to agency practice in light of guidance issued after 

SWANCC and Rapanos, the final rule is generally broader, but not broader than 

the prior regulatory definition. See summary response for “Relevance of Flow 

Regime” above, particularly subsections on jurisdiction over intermittent and 

ephemeral waters and the legality of asserting jurisdiction over ephemeral waters. 

Section I of the Technical Support Document discusses the legal basis of the final 

rule, including consistency with the statute and Supreme Court decisions. The 

agencies’ position in regard to tributaries is rooted in a science-based conclusion

that such waters have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

conclusion.

New Mexico Environment Department (Doc. #16552)

8.189 Although the Department recognizes the interrelatedness of all water, to make a 

determination that a water is a "water of the U.S.," there must be, taking the plurality's 

position in Rapanos, both a permanence to the adjacent water or wetland and an 

observable surface connection to the jurisdictional water; or taking Justice Kennedy's 

concurring opinion, if not directly "adjacent" to jurisdictional water (which implies a 

rationale and reasonable connection), there must be a "substantial nexus" between the inquestion water(s) and jurisdictional water. Rapanos, 547 U.S. at 780, citing SWANCC, 

531 U.S. at 167. In both situations, there must be at least some "adjacency" of the water 

or wetland and some permanent or seasonal intermittent flows from the tributary or 

adjacent water and the jurisdictional water or waters. Rapanos, 547 U.S. at 732, n. 5 

("relatively permanent" water does not necessarily exclude streams, rivers, or lakes that 

might dry up in extraordinary circumstances, such as drought, or seasonal rivers, which 

contain continuous flow during some months of the year but no flow during dry months.).

...

It is disconcerting how the Agencies can claim, in light of Rapanos, SWANCC, and 

Riverside Bayview, that all waters that simply touch or connect through a tributary system 

to jurisdictional waters, no matter the lack of permanence, visible hydrologic connection, 

distance, or finding of a "substantial nexus," can be found a federal jurisdictional water. 

The Department agrees with Michael Campbell's assessment that the Rapanos decision 

would reject "that the CWA protects every discernible water that contributes flow, 

directly or indirectly, to a traditionally navigable water, no matter how remote or 

insignificant the contribution-such as an ephemeral stream that might be 100 miles or 
Clean Water Rule Response to Comments – Topic 8: Tributaries

162

more upstream of a traditionally navigable water. Michael Campbell, Waters Protected 

by the Clean Water Act: Cutting Through the Rhetoric on the Proposed Rule, 44 Envtl. L. 

Rep. News & Analysis 10559, 10561 (2014) (emphasis added); citing Rapanos, 547 U.S. 

at 781 (Kennedy, J., concurring). (p. 13, 14)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

the legality of asserting jurisdiction over ephemeral waters. Section I of the 

Technical Support Document discusses the legal basis of the final rule, including 

consistency with the statute and Supreme Court decisions. The agencies’ position in 

regard to tributaries is rooted in a science-based conclusion that such waters have a 

significant nexus either individually or in the aggregate with traditional navigable 

waters, interstate waters, and the territorial seas. Section VII of the Technical 

Support Document discusses the science supporting the agencies’ conclusion.

Nebraska Department of Roads (Doc. #16896)

8.190 Tributaries are defined in rule for the first time, and the definition could be broadly 

interpreted because tributaries “contribute flow” to other waters. NDOR does not support 

a broad definition of tributaries. This definition could include streams that do not 

typically have water or flow, similar to some found in higher topographical regions of

eastern Nebraska, or in the more arid areas found in western Nebraska. It would be 

appropriate to clearly state that tributaries should have perennial or relatively permanent 

flow in order to be considered jurisdictional, to avoid the potential expansion of 

jurisdiction possible with such a broad definition. (p. 2)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters, the 

legality of asserting jurisdiction over ephemeral waters and the requirement of 

“contribute flow.” Section I of the Technical Support Document discusses the legal 

basis of the final rule, including consistency with the statute and Supreme Court 

decisions. The agencies’ position in regard to tributaries is rooted in a science-based 

conclusion that such waters have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion.

State of Alaska (Doc. #19465)

8.191 D. Tributaries – The proposed rule would apply the significant nexus test to 

tributaries and isolated waters, when Justice Kennedy held it was only applicable to 

wetlands.

All tributaries of jurisdictional waters would become jurisdictional by rule. Under the 

2008 guidance, ephemeral (or non-relatively permanent) tributaries to traditional 

navigable waters required a significant nexus to establish jurisdiction. Under the 

Proposed Rule, the agencies determined that all tributaries of traditional navigable 

waters, including ephemeral tributaries, have a significant nexus with traditional 

navigable waters and are therefore proposed to be jurisdictional by rule. The significant 
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163

nexus finding is based on the conclusions of the draft Connectivity Report (EPA 2013), 

which has not been completed, nor does it address Alaska’s unique circumstances. (p. 25)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsection on jurisdiction over intermittent and ephemeral waters. The 

agencies’ position in regard to tributaries is rooted in a science-based conclusion

that such waters have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

conclusion.

Allen Boone Humphries Robinson LLP (Doc. #19614)

8.192 Moreover, the agencies' conclude that all tributaries have a significant nexus to 

jurisdictional waters without any case-specific review to identify factors of significance. 

Thus both the proposed assertion of jurisdiction over all tributaries without any analysis, 

as well as the definition of the term "tributary," are excessively broad. The definition 

could encompass impermanent waters that lack consistent flow, clearly deviating from 

the standard articulated by Justice Scalia in the Rapanos plurality opinion147 and, at the 

least, raising questions under the “significant nexus" test. (p. 7-8)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

the legality of asserting jurisdiction over ephemeral waters. Section I of the 

Technical Support Document discusses the legal basis of the final rule, including 

consistency with the statute and Supreme Court decisions. The agencies’ position in 

regard to tributaries is rooted in a science-based conclusion that such waters have a 

significant nexus either individually or in the aggregate with traditional navigable 

waters, interstate waters, and the territorial seas. Section VII of the Technical 

Support Document discusses the science supporting the agencies’ conclusion.

Lincoln County Conservation District, Washington (Doc. #4236)

8.193 The proposed Waters of the United States Rule does not do a very good job of explaining 

the differing opinions of the Supreme Court in the Rapanos case in a concise and readily 

understandable manner, and it does not do a good job either of explaining how tributaries 

are already treated differently in the existing 2008 Guidance based on whether or not the 

tributaries are perennial or have “relatively permanent” (significant intermittent) flow on 

a seasonal basis, or if the tributaries do not even have “relatively permanent” flow. 

Instead, the proposed rule lumps ephemeral, intermittent and perennial streams into the 

definition of tributaries, as long they “contribute flow” to a traditional navigable water, 

interstate water, or territorial sea, and have a bed, bank and OHWM (ordinary high water 

mark). This lumping of ephemeral, intermittent and perennial streams together is based 

upon EPA’s “Connectivity of Streams and Wetlands to Downstream Waters: A Review 

and Synthesis of the Scientific Evidence,” which is used to conclude that it is reasonable 

 

147 547 Ll.S. at 739 (Finding that the agencies' authority should extend only to "relatively permanent, standing or 

continuously flowing bodies of water" connected to traditional navigable waters.).
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164

to establish categories of water which have a significant nexus to traditional navigable 

waters, interstate waters, or to territorial seas, and that categorically defining nearly all 

tributaries in the country as a significant nexus is justified because it will reduce or 

eliminate case specific jurisdictional determinations and “...improve clarity for 

regulators, stakeholders and the regulated public by defining certain categories of waters 

as ‘Waters of the United States...’”. 

The proposed rule really fails to define tributaries when it uses the term “contribute 

flow,” but then makes no attempt to define what “contribute flow” is supposed to mean. 

The 2008 Guidance mentions that flow volume, flow duration and flow frequency are to 

be considered in any determinations of significant nexus for tributaries. Why aren’t these 

factors mentioned in an easily found location in the proposed rule? Categorically defining 

nearly every tributary as a significant nexus, regardless of whether or not it contributes 

flow on a regular basis with significant flow volume and significant flow duration, does 

not appear to be the intent of any majority of the Supreme Court in the Rapanos case 

decision or the 2008 Guidance either.

The Lincoln County Conservation District does not agree with the term “contribute 

flow” in the proposed rule, without any definition of what “contribute flow” means. In 

the absence of any definition of “contribute flow” in the proposed Rule, the District 

proposes and requests that for any tributary within the county to be considered as “Waters 

of the United States,” it would be required to contribute flow to a larger traditional 

navigable water, interstate water or territorial sea on a regular basis, with significant 

flow volume and significant flow duration. To keep this definition to a reasonable and 

simple basis, contributing flow on a regular basis would involve the contribution of 

significant flow volume for at least 50% or more of the time on a yearly basis for a 

minimum 10 year period or more. A significant flow volume would require at least a flow 

of 1 cfs (cubic foot per second) or more for a significant duration. Since both the plurality 

opinion and the dissenting opinion in the Rapanos case already came to the conclusion 

that the duration of flow for “relatively permanent” or significant intermittent water 

would typically involve at least 3 months of continuous flow, significant flow duration 

would include at least 3 months continuous flow in a given year at 1 cfs or higher. 

Without contributing flow on a regular basis, with significant flow volume and 

significant flow duration, the District does not believe that a tributary has a 

significant effect on the chemical, physical and biological integrity of any traditional 

navigable water, interstate water, or territorial sea downstream, and any such 

tributary should not be categorically classified as “Waters of the United States.” (p. 

2-3)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters, the 

legality of asserting jurisdiction over ephemeral waters and the requirement of 

“contribute flow.” Section I of the Technical Support Document discusses the legal 

basis of the final rule, including consistency with the statute and Supreme Court 

decisions. The final rule does not require an evaluation of flow volume, flow 

duration and flow frequency for tributaries, which was referenced in the 2008 

Guidance, because the agencies have determined that existing science supports the 
Clean Water Rule Response to Comments – Topic 8: Tributaries

165

conclusion that all waters that meet the definition of “tributary” and that are not 

excluded in paragraph (b), have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Section VII of the Technical Support Document discusses this conclusion in 

detail. 

8.194 The proposed rule includes a very broad definition for tributaries that covers any type of 

stream reach, including ephemeral and intermittent reaches within a watershed, and that 

ultimately makes it easier for federal and state regulatory agencies to classify just about 

all parts of defined tributary systems as tributaries under the proposed rule, regardless of 

whether or not they contribute flow on a regular basis, with significant flow volume and 

with significant flow duration to a traditional navigable water. The proposed rule also 

intends to lump all reaches of a stream with the same stream order (size, flow) together 

into one stream reach, including both perennial and intermittent reaches, which ultimately 

leads again to increased ease of classification and regulation. The District has serious 

concerns with regulatory agencies lumping perennial stream reaches in with intermittent 

stream reaches when evaluating tributaries... (p. 5)

Agency Response: See summary response for section 8.1.1. The agencies’ position 

in regard to tributaries is rooted in a science-based conclusion that such waters have 

a significant nexus either individually or in the aggregate with traditional navigable 

waters, interstate waters, and the territorial seas. Section VII of the Technical 

Support Document discusses the science supporting the agencies’ conclusion. 

Various public, private or institutional parties may use or develop many different 

stream classification systems for many different purposes. The final rule does not 

address stream classification in any way. Under the final rule, the agencies or any 

other interested party will still be able to distinguish tributary flow regimes 

(perennial, intermittent, ephemeral).

North Cass Water Resource District (Doc. #5491)

8.195 ...the proposed definition of "tributary" is alarmingly expansive. The proposed rules 

define "tributary" to include any "water" with stream-like physical characteristics, 

including "a bed, banks, and ordinary high water mark" that "contributes flow" directly or 

through "another water" to navigable, interstate, or territorial waters, or an impoundment 

of any of those. The new definition could conceivably include even manmade channels 

that may "contribute flow" at some point to any downstream jurisdictional water. For 

example, consider a manmade pond that overflows during a high water event, then flows 

overland and discharges into a downstream manmade pond; then the downstream 

manmade pond also overflows, flows overland during a high water event, and discharges 

into a manmade ditch; then the manmade ditch discharges into another downstream ditch 

that ultimately discharges into a tributary of a tributary of a navigable/jurisdictional 

water, the new rule suggests the original manmade upstream pond is jurisdictional under 

the definition of "tributary." This seemingly ridiculous example of the breadth of the 

proposed rules may not be the intent of the rules, but would be a consequence of the 

rules. Despite EPA's suggestions otherwise, the new language in the rules that defines 

"tributary" is extremely expansive and does, in fact, greatly extend the jurisdiction of 

EPA and the Corps under the CWA. (p. 2) 
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166

Agency Response: See summary response for “Definition” above.

Alameda Corridor East Construction Authority et al. (Doc. #8534.1)

8.196 2. We request that the rule specifically state that delineated tributaries on a site do not 

require documentation of the extent of the upstream tributary. This process should be left 

for situations where an applicant is attempting to show that a drainage is not a tributary. 

We are concerned that in practice, we may be asked to document the upstream limits of 

all tributaries on all project sites, which would be very time consuming and costly. (p. 2)

Agency Response: The agencies do not currently require the regulated public to 

delineate waters upstream from the segment of tributary in question. The final rule 

does not deviate from the current practice.

Pasco County, Florida (Doc. #9697)

8.197 Previous guidance deemed tributaries as jurisdictional by rule without the need for a 

significant nexus determination only when the tributaries "are relatively permanent where 

the tributaries typically flow year-round or have continuous flow at least seasonally (e.g., 

typically three months)." That guidance also specifically noted that "relatively 

permanent" waters "do not include ephemeral tributaries which flow only in response to 

precipitation and intermittent streams which do not typically flow year-round or have 

continuous flow at least seasonally." However, CWA jurisdiction over these waters will 

be evaluated under the significant nexus standard. The omission of the "relatively 

permanent" requirement would substantially expand the number of tributaries that could 

be deemed jurisdictional by rule. In effect, a tributary would be deemed jurisdictional by 

rule without any consideration of the flow regime in that tributary. A stream with 

intermittent or even ephemeral flow could be found jurisdictional by rule, simply because 

it has an indirect, infrequent downstream connection to a jurisdictional water. The phrase 

"contributes flow, either directly or through another water" could be interpreted very 

broadly, so that it encompasses waters that have a highly remote or tenuous downstream 

connection to other jurisdictional waters.

Recommendation: the Final Rule should be modified to say that tributaries are 

jurisdictional by rule only if they have a "relatively permanent flow" (or an equivalent 

requirement, such as "perennial flow"), meaning that they "typically flow year-round or 

have continuous flow at least seasonally (e.g., typically three months)." If relatively 

permanent flow is not found, the tributary still could be evaluated under the significant 

nexus test. This would be consistent with the 2008 Guidance Document. Also, it should 

be clarified in the Final Rule that a tributary does not "contribute flow" to another water 

if its only connection to that water is "insubstantial or remote." (p. 2-3)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

the requirement of “contribute flow.” The final rule, like the proposed rule, 

establishes categorical jurisdiction over all waters that meet the definition of 

“tributary” and that are not excluded in paragraph (b). This position is rooted in a 

science-based conclusion that such waters have a significant nexus either 

individually or in the aggregate with traditional navigable waters, interstate waters, 
Clean Water Rule Response to Comments – Topic 8: Tributaries

167

and the territorial seas. Section VII of the Technical Support Document discusses 

the science supporting the agencies’ conclusion.

Pikes Peak Area Council of Governments (Doc. #9732)

8.198 Ephemeral and intermittent streams, including normally dry arroyos and washes, which 

are extremely common in Colorado due to the arid conditions, would be considered 

tributary waters under the proposed guidance and therefore subject to federal 

regulations...Many such tributaries are not physically connected to waters of the US 

through other than extremely infrequent surface flow, and it should not be assumed that 

such ephemeral or intermittent streams/waterways are "per se" jurisdictional. This 

language needs to be modified. (p. 1)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly the subsection on jurisdiction over intermittent and ephemeral waters. 

The final rule, like the proposed rule, establishes categorical jurisdiction over all 

waters that meet the definition of “tributary” and that are not excluded in 

paragraph (b). This position is rooted in a science-based conclusion that such 

waters have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

conclusion.

Clark County Regional Flood Control District (Doc. #11726)

8.199 Under the proposed rule, ephemeral washes that have a bed and bank and ordinary high 

water mark would by rule be jurisdictional waters. However, a ditch that 1) is excavated 

wholly in uplands; 2) drains only uplands; and 3) has less that perennial flow would be 

exempt from the definition of "waters of the United States" and not subject to regulation 

under the Clean Water Act. Ephemeral washes in the desert southwest, excavated by 

infrequent flow in response to highly localized and very intense rainfall, largely meet 

the definition of the excluded ditches. (p. 2)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly the subsection on jurisdiction over intermittent and ephemeral waters. 

The final rule, like the proposed rule, establishes categorical jurisdiction over all 

waters that meet the definition of “tributary” and that are not excluded in 

paragraph (b). This position is rooted in a science-based conclusion that such 

waters have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

conclusion.

Brown County, Kansas (Doc. #13603)

8.200 We object to the definition of a tributary as it extends definition of waters of the US 

upstream to erosion features, and stretches of a channel that are merely short term 

conduits for surface water that have no significant nexus to downstream water quality. 

These ephemeral channels only carry surface water immediately after a major rainfall 

event. Physical, chemical and biological processes are limited due to the short time 
Clean Water Rule Response to Comments – Topic 8: Tributaries

168

period water is flowing in the channel so there can be no significant nexus to downstream

water quality. For this reason we believe that that first stream order ephemeral channels 

in waters of the US until there is science to show where along the channel significant 

processes occur in the channel that have a significant affect downstream, and that 

regulations that protect waters of the US will have a significant effect on downstream 

water quality. (p. 2)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly the subsection on jurisdiction over intermittent and ephemeral waters. 

The final rule, like the proposed rule, establishes categorical jurisdiction over all 

waters that meet the definition of “tributary” and that are not excluded in 

paragraph (b). This position is rooted in a science-based conclusion that such 

waters have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

conclusion.

North Dakota Association of Soil Conservation Districts (Doc. #15168)

8.201 1. Tributaries

The proposed rule’s definition of tributaries as perennial, intermittent and ephemeral can 

be interpreted to include a vast group of waters never intended to be regulated under 

CWA. Rulemaking should be clear and concise. NDASCD requests the term 

“ephemeral” not be used.

We are concerned the proposed rule may potentially allow regulation of on-farm ditches, 

ponds and isolated wetlands which may have a hydrologic connection to navigable 

waters, which flies in the face of the SWANCC ruling. Farm ditches, waterways, holding 

ponds and other structures are often constructed to improve water quality and water 

usage. We urge you to limit your jurisdiction to traditionally navigable waters. In areas of 

discrepancy, we encourage you to consult with local agencies such as soil conservation 

districts, water resource boards and others to develop local parameters, criteria and 

standards. (p. 1-2)

Agency Response: The final rule includes specific exclusions for many ditches, as 

well as artificial lakes and ponds created in dry land and used primarily for stock 

watering, irrigation, settling basins, etc. (see paragraph (b) of the final rule). 

Excluded features are not jurisdictional waters of the United States. In addition, all 

existing statutory exemptions, including those at CWA section 404(f) for normal 

farming, silviculture and ranching activities and for maintenance of existing 

irrigation and drainage ditches remain in effect and unchanged by the final rule.

Los Angeles Department of Water and Power (Doc. #15238)

8.202 Tributaries can be perennial, intermittent, and ephemeral. The Agencies propose to 

regulate tributaries using jurisdiction by rule. In the proposed rule, the Agencies define a 

tributary as a water physically characterized by a bed and banks and ordinary high water 
Clean Water Rule Response to Comments – Topic 8: Tributaries

169

mark; which contributes flow to another water, regardless of whether the waterbody has 

man-made or natural breaks in flow.148

The Agencies' approach is over-inclusive. LADWP believes that there will be 

circumstances where tributaries are jurisdictional, however as written in the proposed 

rule, most or any tributary could become jurisdictional. Under this scenario, the 

permitting process could interfere with the reliability of LADWP's system in cases due to 

circumstances beyond LADWP's control or because a natural disaster has occurred and 

requires immediate attention. The plurality in Rapanos vs. the United States held that to 

be regulated under the CWA, a non-navigable tributary must have permanent water 

flowing and it must have significant impacts to the downstream navigable water. In his 

concurring opinion, Justice Kennedy disputed that permanent flow was required, but 

echoed the requirement that non-navigable tributaries must affect downstream navigable 

water quality to be regulated under the CWA.149 Therefore, in order for a non-navigable 

tributary to be jurisdictional by the CWA, it must have permanent water flowing and 

significant impacts to the downstream navigable water. (p. 3)

...

LADWP suggests that the Agencies clarify the language as follows:

 Waters in different watersheds should not be deemed tributaries to each other and 

that any "connection" between them cannot constitute a significant nexus;

... (p. 3, 4)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters, the 

legality of asserting jurisdiction over ephemeral waters and the requirement of 

“contribute flow.” Section I of the Technical Support Document discusses the legal 

basis of the final rule, including consistency with the statute and Supreme Court 

decisions. The agencies’ position in regard to tributaries is rooted in a science-based 

conclusion that such waters have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion.

Washington County Commission, Utah (Doc. #15448)

8.203 ...the Agencies' proposed rule would greatly expand the Agencies' jurisdiction beyond 

what is permissible under the law. Dry washes do not have a "significant nexus'" to 

traditional jurisdictional waters such as navigable waterways. Flow from any WOUS, 

eliminating the need for case-specific dry wash rarely, if ever, contributes to 

jurisdictional water. When the flow does reach jurisdictional water, it only does so for a 

time period lasting mere hours to a day or two. A rule that establishes all dry washes as 

jurisdictional clearly is not supported by the CWA or U.S. Supreme Court case law. (p. 3)

 

148 79 Federal Register, 22263

149 Rapanos, 547 U.S. at 781-82
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170

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

the legality of asserting jurisdiction over ephemeral waters. Section I of the 

Technical Support Document discusses the legal basis of the final rule, including 

consistency with the statute and Supreme Court decisions. 

Colorado Springs Utilities (Doc. #16351.1)

8.204 The proposal would establish ephemeral and intermittent waterbodies as jurisdictional by 

rule regardless of how tenuous their connection to a TNW. Such drainages are common 

in the arid West, flowing only periodically in response to infrequent precipitation events 

or snowmelt run-off. However, infrastructure must oftentimes cross such features, 

creating new permitting/NEPA hurdles. On a similar note, dry arroyos, washes and 

similar erosion features may now, without further clarification, be treated as 

jurisdictional. (p. 2)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly the subsection on jurisdiction over intermittent and ephemeral waters. 

The final rule, like the proposed rule, establishes categorical jurisdiction over all 

waters that meet the definition of “tributary” and that are not excluded in 

paragraph (b). This position is rooted in a science-based conclusion that such 

waters have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

conclusion.

South Kansas Groundwater Management District No. 3, Garden City, Kansas (Doc. #16465)

8.205 The proposed rule will unnecessarily expanding the CWA's jurisdiction and increasing 

confusion about how it will be implemented will make it more difficult to meet water 

needs. In order to meet water supply and wastewater treatment needs, as well as 

stormwater control requirements, water suppliers like irrigation districts and municipal 

utilities must make substantial infrastructure investments. These investments will include 

new or expanded storage reservoirs; reuse facilities; desalinization plants; water 

collection, delivery and distribution canals, ditches and pipelines; pump-back projects; 

groundwater recharge facilities; and reverse osmosis water treatment plants. Many of 

these facilities will, of necessity, be in somewhat close proximity to the types of "waters" 

discussed in the current proposal. It is essential that these critical activities, many of 

which may be undertaken in direct response to emergency conditions related to drought, 

fire, or post-fire damage, do not unnecessarily trigger a federal nexus and its lengthy and 

costly permitting procedures...

To address the issues identified in this letter the Federal Agencies should:

...

 Clarify that jurisdictional "tributaries" are limited to waters that determinations 

where waters contribute direct flow to a traditional navigable water via a 

continuous surface connection;

... (p. 3)
Clean Water Rule Response to Comments – Topic 8: Tributaries

171

Agency Response: The final rule will clarify and simplify implementation of the 

CWA through clearer definitions and increased use of bright-line rules. The final 

rule includes specific exclusions for many ditches, as well as artificial lakes and 

ponds created in dry land and used primarily for stock watering, irrigation, settling 

basins, etc. (see paragraph (b) of the final rule). There are additional exclusions for 

waste treatment systems designed to meet the requirements of the CWA, 

stormwater control features created in dry land, and wastewater recycling 

structures constructed in dry land. None of these excluded features will be 

jurisdictional waters of the United States. In addition, all existing statutory 

exemptions, including those at CWA section 404(f) for maintenance of existing 

irrigation and drainage ditches remain in effect and unchanged by the final rule. 

See the preamble of the final rule for additional information on the rule’s 

exclusions. Also Topic 6 of this RTC addresses ditches and the ditch exclusions, and 

Topic 7 covers exclusions other than ditches.

Snowmass Water and Sanitation District, Snowmass Village, Colorado (Doc. #16529)

8.206 2. Tributaries.

The proposed definition of a jurisdictional "tributary" would significantly expand the 

scope of CWA jurisdiction. "Tributary" would be defined as any water that is physically 

characterized by the presence of a bed and bank and ordinary high water mark and which 

contributes flow (flow, directly or indirectly) to other waters that eventually flow into a 

traditional navigable water or interstate water. We have the following concerns with this 

approach: to a TNW. 

A. The treatment of all "tributaries" as jurisdictional-by-rule would inappropriately lump 

together large rivers and perennial streams with minor, often dry ephemeral and 

intermittent drainages. Under the proposed rule, there would be no minimum frequency, 

duration or volume of flow required-perennial, intermittent, and ephemeral streams 

would all automatically qualify as jurisdictional tributaries.150 This fails to recognize that 

there are differences among various types of drainages and even within individual 

drainages in terms of their associated resources and potential for affecting the chemical, 

physical or biological integrity of downstream waters. This is especially true for drainage 

areas that are dry during all or part of most years. It is important to preserve a process for

individually determining the jurisdictional status of ephemeral and intermittent drainages 

that can consider and accommodate the variability between drainage types and how they 

differ regionally.

...

C. This proposal would change the jurisdictional status of many ephemeral and 

intermittent drainages in the arid West that have long been regarded as non-jurisdictional. 

The vast majority of drainages in Colorado fit in this category. The expansion of 

jurisdiction under the regulatory changes proposed may have serious unintended 

consequences, including the risks inherent in a regulatory approach that will consume and 

 

150 Definition of "Waters of the United States" under the Clean Water Act, 79 Fed. Reg. at 22202.
Clean Water Rule Response to Comments – Topic 8: Tributaries

172

dilute scarce federal and non-federal agency resources as the result of the extension of 

jurisdictional status to virtually the entire universe of drainages.

Accordingly, if the agencies proceed to establish a jurisdictional-by-rule category for 

"tributaries," that category should be restricted to features that contribute flow to a 

traditional navigable water on a relatively permanent basis, consistent with the plurality 

opinion in Rapanos. The agencies should evaluate intermittent and ephemeral water 

bodies on a case-by-case basis to determine whether to treat a given water as 

jurisdictional, consistent with current practice. These case-by-case evaluations could be 

facilitated through further guidance on factors (such as frequency, duration and volume 

of flow) indicative of the varying strengths of connections between features and the 

jurisdictional waters into which they convey flow. Other factors could include the 

strength (or lack) of the ordinary high water mark and bed/bank indicators, the presence 

and length of breaks in jurisdictional features, flow loss from infiltration and 

evaporation, and distance to a traditional navigable water. This type of approach would 

be consistent with Justice Kennedy's concurring opinion, which suggested the need for 

"more specific" criteria defining jurisdictional tributaries. (p.3, 4-5)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

the legality of asserting jurisdiction over ephemeral waters. Section I of the 

Technical Support Document discusses the legal basis of the final rule, including 

consistency with the statute and Supreme Court decisions. Section VII of the 

Technical Support Document discusses the science supporting the agencies’ 

conclusion that all waters that meet the definition of “tributary” and that are not 

excluded in paragraph (b), have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas.

Water Managers, Kaweah and Tule Watersheds, San Joaquin Valley, California (Doc. #16544)

8.207 The use of the term “contributes flows” alone, without more limiting conditions or 

elements, will bring into play countless streams, creeks, rivulets, washes, and other 

features (roads, gutters, etc.) where water does, will, or could run to (eventually) 

navigable waters. The Agencies themselves profess to not anticipate this outcome. Their 

explanation for the rule, as described in the rule making notice, asserts that tributaries are 

appropriate for jurisdiction because they “exert a strong influence on the character and 

functioning of downstream traditional navigable waters, interstate waters, and the 

territorial seas, either individually or cumulatively.” (Federal Register, Vol. 79 No. 76, 

April 21, 2014, p. 22197.) Yet the rule itself does not require this characteristic; rather, a 

water body may be considered tributary if it merely “contributes flow”. The Kaweah and 

Tule Commenters suggest that the Agencies’ own phrase, quoted earlier, should appear in 

the rule itself. In other words, a water body may be considered tributary, and therefore 

“jurisdictional”, only if it features a defined bed and banks with a mean high water mark 

AND contributes flow that “exerts a strong influence on the character and functioning of 

downstream traditional navigable waters.”

Further, the Kaweah and Tule Commenters have experienced attempts by the Agencies to 

assert jurisdiction over water bodies that receive water from navigable water bodies; in 
Clean Water Rule Response to Comments – Topic 8: Tributaries

173

other words, the reverse of tributary. Present rules and the current proposal both appear to 

adequately define tributary as “contributing to downstream waters”, and not “receiving 

from upstream waters.” However, given the history of attempts by the agencies to apply a 

“reverse tributary” rule, the Kaweah and Tule Commenters request that an express 

exclusion for water bodies that merely receive water from upstream navigable waters be 

stated in the rule’s definition of “tributary”. (p. 3)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

the requirement of “contribute flow.” The final rule, like the proposed rule, 

establishes categorical jurisdiction over all waters that meet the definition of 

“tributary” and that are not excluded in paragraph (b). This position is rooted in a 

science-based conclusion that such waters have a significant nexus either 

individually or in the aggregate with traditional navigable waters, interstate waters, 

and the territorial seas. Section VII of the Technical Support Document discusses 

the science supporting the agencies’ conclusion. The commenter did not provide 

enough information in his scenario describing “jurisdiction over water bodies that 

receive water from navigable water bodies,” and we cannot provide an accurate 

response. 

County Commissioners, Hot Springs County, Wyoming (Doc. #16676)

8.208 As noted by the Congressional Research Service, the rule defines tributary for the first 

time and does so "broadly."151 The Hot Springs County Commission objects to this 

expansive definition that automatically declares a tributary a water of the U.S. even if it 

only sometimes contributes flow to another water that only sometimes contributes flow to 

still another water, and on and on until eventually the flow drains into a currently 

jurisdictional water. At best, when combined with the terms "adjacent," "neighboring," 

and excluded "ditches," the definition provides no certainty to Wyoming's counties or 

constituents about what is considered jurisdictional waters, even when they flow for only 

very brief periods. At worst, when taken in the context of the recently released and 

aforementioned U.S. Geological Survey (USGS) maps, the definition could be construed 

to wrest jurisdictional control of all of Wyoming's approximately 270,000 miles of 

streams, over 80% of which are intermittent or ephemeral.

In response to requests from the House Committee on Science, Space and Technology, 

the EPA insists that the USGS maps have not been used for regulatory purposes, and 

further, that the "EPA is not aware of maps prepared by any agency, including the EPA, 

of waters that are currently jurisdictional under the CWA or that would be jurisdictional 

under the proposed rule.152

The EPA's response poses two related problems. First, given the domino effect of the 

tributary definition, the USGS maps illustrate the potential reach of the proposed rule 

 

151 EPA and the Army Corps' Proposed Rule to Define “Waters of the United States.” Copeland, Claudia.

Congressional Research Service. June 24, 2014.

152 Letter from Nancy Stoner, Acting Assistant Administrator, to U.S. Representative Lamar Smith. July 28, 2014.

Available at 

http://science.house.gov/sites/republicans.science.house.gov/files/documents/epareleases_maps_letter.pdf
Clean Water Rule Response to Comments – Topic 8: Tributaries

174

regardless of the EPA's use of the maps to date. As a headwaters county, Hot Springs 

County is particularly sensitive to the discussion of headwaters in the proposed rule. The 

EPA repeatedly argues that headwaters are particularly important to regulate because of 

their effects on downstream, jurisdictional waters, even if the headwaters are intermittent, 

ephemeral, or are a "substantial distance from the nearest [jurisdictional water].”153 The 

EPA claims that no case-specific analysis is necessary on these often dry creek beds 

because "tributaries, including headwaters, intermittent, and ephemeral streams, and

especially when all tributaries in a watershed are considered in combination, have a 

significant nexus to traditional navigable waters."154 (emphasis added) Despite the EPA's 

claims of a limiting rule, it is difficult for a reasoned observer to not view these 

statements in plain writing as a dramatic, in fact unprecedented, grab for federal 

authority.

The second problem posed by the EPA's response to the House Committee on Science, 

Space, and Technology is that if the USGS maps have not been used as EPA claims, and 

if no such maps exist in any agency, then clarity as to what is a tributary and what is not 

simply cannot be offered by the EPA, USACE or any other agency. No baseline data 

exists, and no map exists to show potential impacts.

Further, the EPA has not defined what aerial photography, "reliable" remote sensing data, 

or "other appropriate information" will be allowed. The Hot Springs County Commission 

and its member counties have significant experience (both positive and negative) with the 

United States Department of Interior regarding the development (or lack thereof) of 

accurate, on-the-ground information used to develop federal policy. We strongly believe 

that any determination of land or water must first be vetted and proven by the local 

government as co-regulators. (p. 5-6)

Agency Response: Cooperative federalism is a hallmark of the CWA, and this 

rule does nothing to change current practice. The agencies do not have maps 

illustrating the extent of jurisdictional waters of the United States. Determining the 

jurisdictional status of a water feature often requires site specific knowledge. 

Although the final rule provides increased clarity and “bright line” distinctions to 

help differentiate waters of the United States from non-jurisdictional features, it will 

not eliminate the need for consideration of site specific knowledge. The agencies 

generally only conduct jurisdictional determinations at the request of individual 

landowners, thus we do not have maps depicting the geographic scope of the CWA. 

Such maps do not exist and the costs associated with a national effort to develop 

them are cost prohibitive and would require access to private property across the 

country. The U.S. Geological Survey and the U.S. Fish and Wildlife Service collect 

information on the extent and location of water resources across the country and 

use this information for many non-regulatory purposes, including characterizing the 

national status and trends of wetlands losses. This data is publicly available and the 

agencies have relied on USGS and USFWS information to characterize qualitatively 

the location and types of national water resources. This information is depicted on 

 

153 79 Fed. Reg. at 22,206.

154 Id.
Clean Water Rule Response to Comments – Topic 8: Tributaries

175

maps but not for purposes of quantifying the extent of waters covered under CWA 

regulatory programs

City of St. Petersburg, Florida (Doc. #18897)

8.209 ...The definition fails to characterize the type of contribution of flow necessary to trigger 

inclusion as a water of the U.S. A definition that fails to define the connectivity based on 

flow duration (e.g., perennial, seasonal, intermittent, ephemeral) fails to address the 

"significant nexus" issue raised by Justice Kennedy's opinion in Rapanos. Allowing for 

the indirect contribution of flow is also concerning and similarly seems to disregard the 

need for a significant nexus. The City further disagrees with any definition of tributary

that includes lacustrine or wetland features, and supports only a traditional interpretation 

of the term as a stream or river that contributes flow to a larger water body downstream 

or as part of a dendritic river system. (p. 2)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

the legality of asserting jurisdiction over ephemeral waters. Section I of the 

Technical Support Document discusses the legal basis of the final rule, including 

consistency with the statute and Supreme Court decisions. Section VII of the 

Technical Support Document discusses the science supporting the agencies’ 

conclusion that all waters that meet the definition of “tributary” and that are not 

excluded in paragraph (b), have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. The definition of “tributary” in the final rule was modified based on 

comments received on the proposed rule, and now does not include either lacustrine 

or wetland features in the definition.

Massachusetts Department of Environmental Protection (Doc. #19133)

8.210 Massachusetts supports the proposed definition of "tributary" and the confirmation that 

tributary waters have a significant nexus to traditional navigable waters, interstate waters 

(including interstate wetlands), territorial seas and impoundments of these waters" and 

thus, are waters of the United States. We also strongly support the specification that 

tributaries are those waters that contribute flow either directly or through another water to 

the abovementioned waters including wetlands lakes and ponds (even if they lack bed 

and banks or ordinary high water mark) if they contribute flow, either directly or through 

another water to the abovementioned waters. This rule will provide protection to 

headwater streams, which have been substantially degraded across the nation. Headwater 

streams and their associated wetlands are small, often intermittent or ephemeral, and less 

visible systems than rivers, lakes and other large wetlands but they are more vulnerable to 

degradation and loss because of their size and location. Headwater streams and adjacent 

wetlands that do not have a permanent surface water connection (e.g. intermittent and 

ephemeral streams) are particularly vulnerable since they respond quickly to small 

changes in hydrology and adverse water quality impacts from increased impervious 

surfaces and impacts of stormwater. They are also frequently crossed by roadways and 

driveways resulting in fragmentation of aquatic and terrestrial habitats. Massachusetts has 

been working for many years to protect headwater streams since in combination they 
Clean Water Rule Response to Comments – Topic 8: Tributaries

176

form a crucial network that serves to keep the waters of the US clean and healthy. Thus 

we support these protective changes to the rule. (p. 2-3)

Agency Response: The agencies agree with the commenter that headwater 

streams provide important functions that support the chemical, physical and 

biological integrity of downstream waters. In making the determination of which 

waters have a “significant nexus,” the agencies must rely, not only on the science, 

but also on their technical expertise and practical experience in implementing the 

CWA during a period of over 40 years. In addition, the agencies are guided, in part, 

by the compelling need for clearer, more consistent and easily implementable 

standards to govern administration of the CWA, including brighter lines where 

feasible and appropriate. The definition of “tributary” in the final rule was 

modified based on comments received on the proposed rule, and now does not 

include either wetlands, lakes or ponds in the definition.

Mississippi Valley Flood Control Association (Doc. #19488)

8.211 The jurisdiction by rule over tributaries and the definition of “tributary” are too broad. 

The Proposed Rule classifies tributaries as jurisdictional by rule and, for the first time, 

defines the term. The agencies’ conclusion that all tributaries have a significant nexus to 

jurisdictional waters without any case-specific review to identify factors of significance 

exceeds the intended limits of Rapanos. Thus both the proposed assertion of jurisdiction 

over all tributaries without any analysis, as well as the definition of the term “tributary,” 

are excessively broad. 

“Tributary” is defined in the Proposed Rule as “a water physically characterized by the 

presence of a bed and banks and ordinary high water mark . . . which contributes flow, 

either directly or through another [jurisdictional water],” and, additionally, “wetlands, 

lakes, and ponds are tributaries (even if they lack a bed and banks or ordinary high water 

mark) if they contribute flow.”155 The definition contains no reference to the volume or 

frequency of such flow, creating uncertainty and the potential for jurisdictional overreaching. The definition could encompass impermanent waters that lack consistent flow, 

clearly deviating from the standard articulated by Justice Scalia in the Rapanos plurality 

opinion156 and, at the least, raising questions under the “significant nexus” test. (p. 9)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

the legality of asserting jurisdiction over ephemeral waters. Section I of the 

Technical Support Document discusses the legal basis of the final rule, including 

consistency with the statute and Supreme Court decisions. Section VII of the 

Technical Support Document discusses the science supporting the agencies’ 

conclusion that all waters that meet the definition of “tributary” and that are not 

excluded in paragraph (b), have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

 

155 79 Fed. Reg. at 22,263.

156 547 U.S. at 739 (Finding that the agencies’ authority should extend only to “relatively permanent, standing or 

continuously flowing bodies of water” connected to traditional navigable waters.).
Clean Water Rule Response to Comments – Topic 8: Tributaries

177

seas. The definition of “tributary” in the final rule was modified based on 

comments received on the proposed rule, and now does not include either lacustrine 

or wetland features in the definition.

California State Association of Counties (Doc. # 9692)

8.212 Tributary: CSAC agrees that this definition should consider bed, bank, and ordinary highwater mark. However, the frequency and amount of flows, infiltration, evaporation, and 

transpiration should also be considered before determining that a feature is a tributary. 

The current definition would not properly account for the dry weather conditions in 

southeastern California. For example, because desert rainfall events are so infrequent in 

these areas (Palm Springs 5 inches/year, Blythe 4 inches/year), the existing bed and 

banks may have been formed during very infrequent events. CSAC believes that defining 

these features as a jurisdictional tributary is not a proper exercise of the agencies' 

authority. 

The CR states that all tributaries, including perennial, intermittent and ephemeral streams 

are connected to downstream rivers via channels and associated alluvial deposits. 

Alluvial deposits should not be used as a basis for connectivity because groundwater is 

not regulated by the CWA. (p. 2-3)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

the legality of asserting jurisdiction over ephemeral waters. Section I of the 

Technical Support Document discusses the legal basis of the final rule, including 

consistency with the statute and Supreme Court decisions. Section VII of the 

Technical Support Document discusses the science supporting the agencies’ 

conclusion that all waters that meet the definition of “tributary” and that are not 

excluded in paragraph (b), have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. The final rule specifically excludes groundwater in paragraph (b), thus 

ensuring that groundwater will not be considered a water of the United States.

National Association of Conservation Districts (Doc. #12349)

8.213 Defining tributaries as perennial, intermittent and ephemeral carries the potential to 

capture a great number of areas unintended by the CWA. EPA is proposing that these 

three categories (perennial, intermittent and ephemeral) are per se jurisdictional without 

the need for a site-specific “significant nexus” test. The term “ephemeral” has different 

meanings throughout the country, and those differences are creating a great deal of 

confusion. Substantially, any use of the term “ephemeral” could fall under the definition 

of “intermittent.” Therefore, NACD requests that this term not be used. (p. 4)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

the legality of asserting jurisdiction over ephemeral waters. Section I of the 

Technical Support Document discusses the legal basis of the final rule, including 

consistency with the statute and Supreme Court decisions. Section VII of the 

Technical Support Document discusses the science supporting the agencies’ 

conclusion that all waters that meet the definition of “tributary” and that are not 
Clean Water Rule Response to Comments – Topic 8: Tributaries

178

excluded in paragraph (b), have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. The agencies believe that there is a difference in the terms ephemeral and 

intermittent, and the Corps has defined these terms previously (March 9, 2000 

Nationwide Permit regulations).

Colorado Stormwater Council (Doc. #12981)

8.214 Definition of Tributary. Existing regulations do not define this term. In practice the 

USACE has regularly determined that many remote ephemeral drainages are not 

WOTUS. The Proposed Rule will bring most, if not all, of these tributaries into the scope 

of jurisdictional WOTUS. This would eliminate the USACE's flexibility in making 

individual determinations based on site-specific conditions. Features that would 

otherwise meet the definition of tributary do not lose that status if, for any length, there 

are natural or manmade breaks, provided that there is an ordinary high water mark 

upstream of the break. The Proposed Rule's definition of tributaries would increase the 

number of hydraulically connected features that are considered tributaries, 

notwithstanding exclusions such as ditches, to traditional navigable waters. (p. 3)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly the subsection on jurisdiction over intermittent and ephemeral waters. 

Section VII of the Technical Support Document discusses the science supporting the 

agencies’ conclusion that all waters that meet the definition of “tributary” and that 

are not excluded in paragraph (b), have a significant nexus either individually or in 

the aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. 

California Building Industry Association et al. (Doc. #14523)

8.215 ...this new definition of tributary and the Proposed Rule’s categorical effect of blanketing 

jurisdiction in all instances in this vague universe of features raises multiple concerns. 

Among them are the fact that ephemeral features that rarely if ever contain an appreciable 

flow are included; many features in MS4 storm sewer systems regulated under CWA 

Section 402 will now be automatically designated waters of the United States rendering 

their intended and permitted operation under one CWA regime illegal; and the 

perpetuation and heightened importance of terms proven problematic in the field such as 

“ordinary high water mark.” (p. 14)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

the legality of asserting jurisdiction over ephemeral waters. Section I of the 

Technical Support Document discusses the legal basis of the final rule, including 

consistency with the statute and Supreme Court decisions. Section VII of the 

Technical Support Document discusses the science supporting the agencies’ 

conclusion that all waters that meet the definition of “tributary” and that are not 

excluded in paragraph (b), have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. The agencies’ longstanding practice is to view stormwater water control 

measures that are not built in “waters of the United States” as non-jurisdictional. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

179

Conversely, the agencies view some waters, such as channelized or piped streams, as 

jurisdictional currently even where used as part of a stormwater management 

system. Nothing in the proposed rule was intended to change that practice, and the 

final rule is consistent with that intent. The term “ordinary high water mark” has 

been defined in the Corps’ regulations since 1986. The final rule does not change 

that definition, but simply incorporates it into EPA’s regulations for consistency 

and clarity.

North Carolina Soil and Water Conservation Commission (Doc. #14790)

8.216 Jurisdiction of Ephemeral Streams

The new definition of “tributary” does not exclude ephemeral water bodies (features 

which contain water only after a precipitation event). Therefore, ephemeral streams or 

water bodies that contain a bed and bank and an ordinary high water mark will be subject 

to jurisdiction.

The SWCC opposes the language of the proposed rule that makes ephemeral streams and 

water bodies subject to jurisdiction. One particular concern of the SWCC is grassed 

waterways. Under no circumstances should grassed waterways, which are a widely 

recognized conservation practice, be considered jurisdictional. (p. 2)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

the legality of asserting jurisdiction over ephemeral waters. Section I of the 

Technical Support Document discusses the legal basis of the final rule, including 

consistency with the statute and Supreme Court decisions. Section VII of the 

Technical Support Document discusses the science supporting the agencies’ 

conclusion that all waters that meet the definition of “tributary” and that are not 

excluded in paragraph (b), have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Grassed waterways are excluded under paragraph (b)(4) of the final rule and 

are therefore not considered waters of the United States.

Western Urban Water Coalition (Doc. #15178.1)

8.217 2.2 Proposed Rule

The proposed rule makes a presumption connectivity report supports the final rule’s 

definition that all tributaries, including ephemeral and intermittent drainages, are 

jurisdictional by rule. This approach lumps together large rivers and perennial streams 

with minor, often dry, ephemeral and intermittent drainages. In doing so, the geographic 

scope of the proposed rule substantially expands the current scope of CWA jurisdiction. 

This is particularly true in the arid West where substantial portions of the landscape are 

comprised of ephemeral and intermittent drainages that are often dry for all or most of the 

year. Some of these western ephemeral and intermittent drainages are supplied seasonally 

by irrigation water surface runoff and or ground water discharges that exist due to 

infiltration of irrigation water to the ground water table.

2.3 Problems with the Proposed Rule
Clean Water Rule Response to Comments – Topic 8: Tributaries

180

The proposed rule presumes that all ephemeral and intermittent drainages that have the 

presence of a bed and banks and a OHWM and that contribute flow, either directly or 

through another water, to a WUS are jurisdictional. The proposed rule does not recognize 

that there are differences among not only types of drainages, but individual drainages and 

their potential for affecting the chemical, physical, or biological integrity of a WUS. The 

proposed presumption of jurisdiction by rule for ephemeral and intermittent drainages

runs counter to the guidance and process established by the SWANCC and Rapanos

opinions. These problems with the proposed rule are discussed further below. (p. 6)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly the subsection on jurisdiction over intermittent and ephemeral waters. 

Section VII of the Technical Support Document discusses the science supporting the 

agencies’ conclusion that all waters that meet the definition of “tributary” and that 

are not excluded in paragraph (b), have a significant nexus either individually or in 

the aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. As described in the Response to Comments from Compendium 6, “Ditches,”

the agencies believe that perennial flow caused by agricultural irrigation is none the 

less perennial flow. Irrigation water that infiltrates the soil surface, percolates 

through the upper soil horizons and is eventually expressed as flow in an adjacent 

ditch or tributary allows that ditch or tributary to effectively function in a similar 

manner as perennial ditches or tributaries whose flow is supported by sources other 

than agricultural irrigation. 

8.218 Compared with rivers and perennial streams, the ecological resources associated with 

ephemeral and intermittent drainages are typically less well developed. The ecological 

resources associated with ephemeral and intermittent drainages can differ substantially 

due to the differences in hydrology (e.g., compare the ephemeral drainages in Photos 1 

through 8 with the intermittent drainages in Photos 9 and 10, Appendix A). The 

aggregation of all tributaries as “jurisdictional by rule” does not consider the continuum 

of resources and functions provided, or not provided, by the wide variety of drainage 

types. (p. 21)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly the subsection on jurisdiction over intermittent and ephemeral waters. 

Section VII of the Technical Support Document discusses the science supporting the 

agencies’ conclusion that all waters that meet the definition of “tributary” and that 

are not excluded in paragraph (b), have a significant nexus either individually or in 

the aggregate with traditional navigable waters, interstate waters, and the territorial 

seas.

8.219 ...Based on the Rapanos opinions, when determining the jurisdiction of tributaries, the 

Corps currently considers a relatively permanent water (RPW) (i.e., a tributary that is not 

a TNW and that typically flows year-round or has a continuous flow at least 

“seasonally”) that is tributary to a TNW to be jurisdictional. This presumption is not 

extended to non-RPWs like ephemeral and intermittent drainages. The non- RPWs are 

subject to a significant nexus analysis (SNA) to determine if the water and/or wetland in 

question have more than a speculative or insubstantial effect on the chemical, physical, 

and/or biological integrity of a TNW.
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The current approach recognizes the wide range of types of non-RPWs and the broad 

continuum of potential effects the non-RPWs could have, or might not have, on the 

chemical, physical, and/or biological integrity of a TNW and, therefore, are WOUS, 

eliminating the need to evaluate non-RPWs individually based on specific facts 

associated with each non-RPW. As discussed below, the arid West provides excellent 

examples of just how varied drainages can be and how this wide variation in drainages 

translates to a broad continuum of potential connections and effects the drainages may or 

may not have on the chemical, physical, and/or biological integrity of a WUS. The 

continuum of potential connections and potential effects on the chemical, physical, and/or 

biological integrity of a WUS are driven by the magnitude, duration, frequency, 

predictability, and location in the watershed of flows in ephemeral and intermittent 

drainages.

Comments from the Science Advisory Board Panel (EPA SAB Panel) for the Review of 

EPA Water Body Connectivity Report expressed a similar concept of a gradient of 

connectivity and stated “... that the concept of a connectivity gradient applies to all 

waters, including tributaries and adjacent waters and wetlands, though most panelists 

agreed that certain types of water bodies typically fall at the higher end of the 

connectivity gradient” (EPA SAB Panel 2014). In commenting on significant nexus, the 

EPA SAB Panel states that “the relative strength of downstream effects should inform the 

conclusions about the significance of those effects for purposes of interpreting the Clean 

Water Act” (EPA SAB Panel 2014, Page 6).

Currently, the Corps considers various factors to determine if a drainage or wetland has a 

significant nexus to a TNW. Consideration of these factors is specific to the water and 

wetland and include: the strength (or lack thereof) of OHWM and bed and bank 

indicators, length of breaks in jurisdictional features and channel deformation, sporadic 

flow, flow loss from infiltration and evapotranspiration, distance to a TNW, 

impoundments, and potential to affect the chemical, physical, and/or biological integrity

of a TNW.

The proposed rule takes a “one size fits all” approach to a very wide range of drainage 

types (except for the narrow range of drainages that qualify as exempt). Assuming that all 

tributaries, including ephemeral and intermittent drainages, are jurisdictional by rule is an 

oversimplification. While this approach may be expedient from the agencies’ perspective, 

it is not supported by the literature (discussed below in Sections 2.4.1 and 2.4.2), 

intuitively does not make sense, is contrary to the Rapanos opinions, and does not 

provide the regulated community an opportunity to demonstrate that an ephemeral or 

intermittent drainage lacks a significant nexus to a jurisdictional water.

The proposed presumption that all waters that meet the definition of tributary are 

jurisdictional by rule is only accurate over a portion of the spectrum of potential tributary 

types. The presumption is applicable at the wet end of the spectrum (e.g., rivers and 

perennial streams) and becomes increasingly less applicable as one moves toward the 

drier end of the tributary spectrum, particularly with smaller drainages in the arid West. 

At the drier portion of the tributary spectrum, the presumption of jurisdictional by rule is 

no longer accurate and becomes arbitrary.

2.4 Description of Ephemeral and Intermittent Drainages in the Arid West
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The following description of ephemeral and intermittent drainages in the arid West is 

provided to demonstrate the physical, hydrological and ecological differences in these 

types of drainages in the arid West compared to more moist regions of the U.S. The 

discussion of current considerations provides context for the how the Corps has 

considered differences in the arid West in developing guidance for its Section 404 

program.

2.4.1 Current Considerations

When considering how ephemeral and intermittent drainages in the arid West differ from 

drainages in other parts of the U.S., it is important to consider how they are currently 

addressed in implementing the CWA. The Corps, through implementation of the Section 

404 program, has provided substantial information on ephemeral and intermittent 

drainages and wetlands in the arid West. The Corps describes “arid West” for its 

Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Arid West 

Region (Version 2.0) as encompassing a wide variety of landforms and ecosystems, but is 

differentiated from the surrounding areas by its predominately dry climate and long 

summer dry season. Annual average precipitation is mostly less than 15 inches and

evapotranspiration exceeds precipitation across most of the region. Drainage basins often 

lack outlets and the water table is often perched. The episodic precipitation patterns often 

lead to a lack of base flow (unless ground water influences are present) and, as a result, 

decreased incision of arid West channel forms (Corps 2008).

For the purposes of these comments, the arid West is defined as the arid and semi-arid 

portions of the western United States that extend from south-central Texas west to 

southeastern California and north along the east side of the Sierra Nevada and Cascade 

Ranges to the Canadian Border in eastern Washington. The eastern boundary of this 

region extends from central North Dakota south through central South Dakota, Nebraska, 

western Kansas, and Oklahoma to south-central Texas. The arid and semi-arid areas of 

this region, which incorporates portions of 17 western states, is characterized generally 

by annual precipitation of less than 10 and 20 inches, respectively (Arid West Water 

Quality Research Project 

http://cdm16658.contentdm.oclc.org/cdm/ref/collection/p267501ccp2/id/1699). 1

The Corps has observed that ephemeral and intermittent channel forms dominate the arid 

West (Lichvar and McColley 2008). When considering the jurisdictional status of 

ephemeral and intermittent drainages and how they fit within the broad spectrum of 

tributary types, it is important to first consider how ephemeral and intermittent drainages 

are treated nationally under Section 404 of the CWA. The Corps currently recognizes the 

differences between an ephemeral stream and an intermittent stream. The Corps defines 

“ephemeral stream” as having “flowing water only during and for a short duration after, 

precipitation events in a typical year. Ephemeral streambeds are located above the water 

table year-round. Ground water is not a source of water for the stream. Runoff from 

rainfall is the primary source of water for stream flow.” The Corps defines “intermittent 

stream” as having “flowing water during certain times of the year, when groundwater 

provides water for stream flow. During dry periods, intermittent streams may not have 

flowing water. Runoff from rainfall is a supplemental source of water for stream flow” 

(77 Fed. Reg. 10288-10289 (February 21, 2012)). Presently, some intermittent drainages 
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with seasonal flows may be considered a RPW and thus jurisdictional (unlike ephemeral 

drainages).

Using the Corps’ definitions, it is clear that ephemeral and intermittent drainages have 

different characteristics that can influence how they could potentially affect the chemical, 

physical, and/or biological integrity of a WUS. These differences can be readily seen by 

comparing Photos 1 through 8 with Photos 9 and 10 (Appendix A).

The proposed rule does not distinguish between ephemeral and intermittent drainages, 

which further underscores how the rule considers all tributaries to be the same and 

inappropriately biases dry intermittent and ephemeral drainages toward jurisdiction as 

“jurisdictional by rule.” These differences are accentuated in the arid West where 

precipitation is limited and seasonal, and year-to-year ground water levels can vary 

considerably. It is also clear that the hydrology of ephemeral and intermittent drainages is 

very different from rivers and perennial streams. The Corps currently recognizes these 

differences in the Nationwide Permit (NWP) regulations. For example, for NWPs 29 

Residential Development, 39 Commercial and Institutional Developments, and 42 

Recreational Facilities, the Corps distinguishes between the impact threshold for loss of 

streambed for perennial streams and ephemeral or intermittent streams. For ephemeral or 

intermittent streambeds, the district engineer can waive the 300-linear-foot impact 

threshold. If the Corps believed that the resources of all tributaries were equal, the 

NWPspecific impact thresholds would not distinguish between perennial streams and 

ephemeral or intermittent streams.

Again, similar to what was previously described for the approved JD process, the Corps’ 

NWP impact thresholds currently recognize the variability in drainage types and the 

variability in resources associated with the drainage types. As described below, 

ephemeral and intermittent drainages can differ significantly from each other physically, 

hydrologically, and ecologically. Because of this variability, it is important to have a 

process for determining the jurisdictional status of ephemeral and intermittent drainages 

that recognizes the variability between these drainage types, how they vary regionally, 

and how different they are from rivers and perennial streams... (p. 13-16)

Agency Response: The longstanding regulatory definition of “waters of the United 

States” included “tributaries” without any limitations regarding volume or duration 

of flow. The December 2008 Guidance on post-Rapanos implementation noted that 

tributaries that flow only in direct response to rainfall are subject to the CWA if 

they have a significant nexus to a downstream traditional navigable water. 

Regulations addressing water quality standards for waters of the United States 

provide that states may modify standards for streams with natural ephemeral flow 

but may not declare an ephemeral stream non-jurisdictional altogether. See, e.g., 40 

CFR § 131.10(g)(2). See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

the legality of asserting jurisdiction over ephemeral waters. Section I of the 

Technical Support Document discusses the legal basis of the final rule, including 

consistency with the statute and Supreme Court decisions. Section VII of the 

Technical Support Document discusses the science supporting the agencies’ 

conclusion that all waters that meet the definition of “tributary” and that are not 

excluded in paragraph (b), have a significant nexus either individually or in the 
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184

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. The exclusions outlined in paragraph (b) are broad and include most ditches 

that are not actually relocated tributaries or excavated in tributaries. As 

summarized in the Science Report, scientific literature unequivocally demonstrates 

that streams, individually or cumulatively, exert a strong influence on the chemical, 

physical, and biological integrity of downstream water, and the Science Advisory 

Board expressed support for the proposed rule’s inclusion of tributaries as 

categorical waters of the United States. The agencies further note that the final rule 

is solely a definitional rule, and specific implementation of permitting programs, 

including the CWA 404 Nationwide Permit program, are beyond the scope of the 

rule.

John Deere & Company (Doc. #14136.1)

8.220 The Proposed Definition For Tributary Sets Forth Poorly Defined and Optional Criteria 

Creating Confusion and Uncertainty

...under the proposed tributary definition, no ordinary high water mark is deemed 

necessary if it is a water that “contributes flow” to certain other jurisdictional waters. 

Specific scientific criteria for identification such as flow duration, volume, and degree are 

not provided. Perhaps the closest the agencies come to defining the term “contributes 

flow” can be found in the rule’s preamble in which they offer that “tributaries do not need 

to flow perennially to have a significant nexus to downstream waters” and that “episodic 

events can be very important for transmitting a substantial amount of material into 

downstream rivers.”15 Apparently, any flow, at any time, over all land features 

functioning as a drainage way leading to waters of the United States would be considered 

within the definition of a tributary and, therefore, subject to regulation. Further adding to 

the confusion is the agencies’ proposal to make all tributaries “jurisdictional by rule” 

meaning that a for case-specific determination will not be conducted. This could mean 

that any water that determinations where waters contribute flow, directly or indirectly 

“contributes flow” to a jurisdictional water, is now considered a jurisdictional water. 

Moreover, under the proposed tributary definition, no ordinary high water mark is 

deemed necessary if it is a water that “contributes flow” to certain other jurisdictional 

waters. Specific scientific criteria for identification such as flow duration, volume, and 

degree are not provided. Perhaps the closest the agencies come to defining the term 

“contributes flow” can be found in the rule’s preamble in which they offer that 

“tributaries do not need to flow perennially to have a significant nexus to downstream 

waters” and that “episodic events can be very important for transmitting a substantial 

amount of material into downstream rivers.”15 Apparently, any flow, at any time, over 

all land features functioning as a drainage way leading to waters of the United States 

would be considered within the definition of a tributary and, therefore, subject to 

regulationto a TNW.

Further adding to the confusion is the agencies’ proposal to make all tributaries 

“jurisdictional by rule” meaning that a case-specific determination will not be conducted. 

This could mean that any water that directly or indirectly “contributes flow” to a 

jurisdictional water, is now considered a jurisdictional water. (p. 8)
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185

Agency Response: The definition of “tributary” in the final rule specifically 

requires physical indicators of bed and bank and an ordinary high water mark in 

order for a feature to be considered a tributary. The simple fact that a feature 

might “contribute flow” to a jurisdictional water does not automatically make that 

feature a tributary. Furthermore, the exclusions outlined in paragraph (b) of the 

final rule are broad and include most ditches that are not actually relocated 

tributaries or excavated in tributaries. See summary response for “Relevance of 

Flow Regime” above, particularly subsections on jurisdiction over intermittent and 

ephemeral waters, the legality of asserting jurisdiction over ephemeral waters and 

the requirement of “contribute flow.” Section I of the Technical Support Document 

discusses the legal basis of the final rule, including consistency with the statute and 

Supreme Court decisions. Section VII of the Technical Support Document discusses 

the science supporting the agencies’ conclusion that all waters that meet the 

definition of “tributary” and that are not excluded in paragraph (b) have a 

significant nexus either individually or in the aggregate with traditional navigable 

waters, interstate waters, and the territorial seas. 

Corporate Environmental Enforcement Council, Inc. (Doc. #14608)

8.221 ...how will contribution be measured? Will it be based on volume alone or instead on 

some combination of volume, duration, frequency, magnitude, predictability and impact? 

The proposed definition also says that a tributary will still be jurisdictional even in the 

face of man-made breaks such as bridges, culverts, pipes or dams. But how will this be 

interpreted in the field? How far back in time will the Agencies go to establish 

jurisdiction? CEEC notes that many of the Nation’s iconic city-scapes, including 

Washington, D.C. and New York City have been built on, over or adjacent to natural 

rivers, streams and wetlands. Over time, most of these natural features have been bridged, 

culverted, piped and dammed to provide space for structures, roads and other urban 

infrastructure. Are these century-old and now heavily engineered natural features 

jurisdictional? (p. 7)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters, the 

requirement of “contribute flow” and regulation of man-altered streams. 

Determinations of whether a water “contributes flow” are expected to be done in a 

manner similar to what has been practiced in the field for decades. While precise 

measurements of flow volume and duration are not required, tools such as aerial 

photographs, topographic maps, flow gauges, and the like will be helpful in 

determining contribution of flow. The final rule preamble discusses this process in 

greater length in Section IV.F.1. Section VII of the Technical Support Document 

discusses the science supporting the agencies’ conclusion that all waters that meet 

the definition of “tributary” and that are not excluded in paragraph (b) have a 

significant nexus either individually or in the aggregate with traditional navigable 

waters, interstate waters, and the territorial seas. Section VII also specifically 

discusses man-made or man-altered tributaries and their effect on the physical, 

chemical and biological integrity of traditional navigable waters, interstate waters 

and the territorial seas. Man-made and man-altered tributaries, despite human 

manipulation, usually continue to have chemical, physical, or biological connections 
Clean Water Rule Response to Comments – Topic 8: Tributaries

186

downstream and to serve important functions downstream. Tributary ditches and 

other man-made or man-altered waters that meet the definition of “tributary” have 

a significant nexus to traditional navigable waters, interstate waters, and the 

territorial seas due to their impact, either individually or with other tributaries, on 

the chemical, physical, or biological integrity of those downstream waters. .

Arizona Chamber of Commerce and Industry (Doc. #14639)

8.222 The proposed rule also improperly attempts to extend federal jurisdiction to all tributaries 

to traditional navigable waters, including all ephemeral tributaries (i.e., tributaries that 

flow only in response to storm events). The proposed expansion of federal jurisdiction to 

all ephemeral features in Arizona’s desert lands is not supported by science and clearly 

exceeds the EPA and Corps’ authority under the Clean Water Act.

The science underlying this proposal was developed in Eastern states that receive far 

more rain and is simply not applicable to the arid West, where hydrologic drainage 

conditions are very different. The proposal to extend jurisdiction to all ephemeral 

tributaries no matter how small or remote from traditional navigable waters would have a 

disproportionate impact on states such as Arizona that have vast areas of desert lands 

characterized by sparse vegetation, highly erodible soils, and infrequent, but high 

intensity, rain events. These conditions result in numerous erosional features, such as 

small dry desert washes and arroyos that crisscross the desert landscape. Although these 

erosional features would seldom if ever contribute flow to a traditional navigable water, 

the proposed rule appears to suggest that the mere presence of bed and banks and 

ordinary high water mark is sufficient evidence of flow to extend jurisdiction to even 

ephemeral drainage features in arid landscapes. (p. 2)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters, the 

legality of asserting jurisdiction over ephemeral waters and the requirement of 

“contribute flow.” Section I of the Technical Support Document discusses the legal 

basis of the final rule, including consistency with the statute and Supreme Court 

decisions. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion that all waters that meet the definition of 

“tributary” and that are not excluded in paragraph (b) have a significant nexus 

either individually or in the aggregate with traditional navigable waters, interstate 

waters, and the territorial seas.

Greater Houston Partnership (Doc. #14726)

8.223 GHP is also concerned that the approach used in current guidance to assert jurisdiction 

over tributaries has been abandoned in the proposed rule. Under current guidance the 

agencies have indicated that they would only assert jurisdiction over non-navigable 

tributaries of traditional navigable water that are relatively permanent where tributaries 

typically flow year round or have continuous flow at least seasonally (at least three 

months per year). GHP suggests that this current guidance approach be incorporated into 

the rulemaking and continued. (p. 2)

Agency Response: The longstanding regulatory definition of “waters of the United 

States” included “tributaries” without any limitations regarding volume or duration 
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187

of flow. The December 2008 Guidance on post-Rapanos implementation noted that 

tributaries that flow only in direct response to rainfall are subject to the CWA if 

they have a significant nexus to a downstream traditional navigable water. 

Regulations addressing water quality standards for waters of the United States 

provide that states may modify standards for streams with natural ephemeral flow 

but may not declare an ephemeral stream non-jurisdictional altogether. See, e.g., 40 

CFR § 131.10(g)(2). See summary response for “Relevance of Flow Regime” above, 

particularly the subsection on jurisdiction over intermittent and ephemeral waters.

Indiana Cast Metals Association (Doc. #14895.1)

8.224 The proposed rule would assert jurisdictional authority over countless dry creeks, ditches, 

swales and low spots that are wet only occasionally because it rains. Even worse, the 

proposed rule attempts to claim authority over remote “wetlands” and other drainage 

features solely because they are near an ephemeral drainage feature or ditch that are now 

defined as a water of the U.S. subject to CWA jurisdiction. Such unnecessary expansion 

of CWA jurisdiction significantly burdens metalcasting operations without providing any 

meaningful human health or environmental benefits. (p. 2)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters. 

Section VII of the Technical Support Document discusses the science supporting the 

agencies’ conclusion that all waters that meet the definition of “tributary” and that 

are not excluded in paragraph (b) have a significant nexus either individually or in 

the aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Paragraph (b) of the final rule outlines numerous exclusions for features that 

will not be waters of the United States, including most ditches that are not relocated 

tributaries or excavated in tributaries, water-filled depressions created in dry land 

incidental to mining or construction activity and erosional features, including 

gullies, rills, and other ephemeral features that do not meet the definition of 

“tributary.” 

Landmark Legal Foundation (Doc. #15364)

8.225 The nearly boundless new authority the Agencies seek is demonstrated by the 

examination of EPA-created maps displaying what it considers wetlands and waterways. 

The maps were provided to the US. House of Representative's Committee on Science, 

Space and Technology ("Committee") and are publically available via the Committee's 

website. (http://science.house.gov/epa-maps-state-20 l3#overlay-context). These maps 

display what EPA labels "perennial, intermittent and ephemeral streams"

Looking at EPA's maps of Missouri, for example, would lead one to think that the entire 

state is a waterway of some sort or other. (It is not.) (Exhibit I, "Streams and Waterbodies 

in Missouri," and Exhibit 2, "EPA Region 7 National Wetlands Inventory.") As presented 

in these maps, "waterbodies'' cover the entirety of the states -including non-navigable, 

and non-adjacent waters. EPA's maps demonstrate EPA's and the Corps' intent to expand 

their regulatory and permitting powers under the Clean Water Act to all water-navigable 

or non, permanent or fleeting. (p. 10-11)
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188

Agency Response: The agencies do not have maps illustrating the extent of 

jurisdictional waters of the United States. Determining the jurisdictional status of a 

water feature often requires site specific knowledge. Although the final rule 

provides increased clarity and “bright line” distinctions to help differentiate waters 

of the United States from non-jurisdictional features, it will not eliminate the need 

for consideration of site specific knowledge. The agencies generally only conduct 

jurisdictional determinations at the request of individual landowners, thus we do 

not have maps depicting the geographic scope of the CWA. Such maps do not exist 

and the costs associated with a national effort to develop them are cost prohibitive 

and would require access to private property across the country. The U.S. 

Geological Survey and the U.S. Fish and Wildlife Service collect information on the 

extent and location of water resources across the country and use this information 

for many non-regulatory purposes, including characterizing the national status and 

trends of wetlands losses. This data is publicly available and the agencies have 

relied on USGS and USFWS information to characterize qualitatively the location 

and types of national water resources. This information is depicted on maps but not 

for purposes of quantifying the extent of waters covered under CWA regulatory 

programs.

Idaho Association of Commerce & Industry (Doc. #15461)

8.226 IACI objects to the Agencies' proposal to categorically regulate all "tributaries." a term 

that includes intermittent and ephemeral streams and most ditches...Accordingly, the 

Agencies should revise their jurisdictional-by-rule proposal to clarify that jurisdictional 

"tributaries" are limited to waters that contribute direct flow to a traditional navigable 

water via a continuous surface connection... (p. 3)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly the subsection on jurisdiction over intermittent and ephemeral waters. 

Section VII of the Technical Support Document discusses the science supporting the 

agencies’ conclusion that all waters that meet the definition of “tributary” and that 

are not excluded in paragraph (b) have a significant nexus either individually or in 

the aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Paragraph (b) of the final rule outlines numerous exclusions for features that 

will not be waters of the United States, including most ditches that are not relocated 

tributaries or excavated in tributaries.

American Council of Engineering Companies (Doc. #15534)

8.227 In the past, ephemeral streams, ephemeral ditches, and other waters with less than 

intermittent flow or flow only in direct response to rainfall have commonly been 

determined to be non-jurisdictional features with no regulatory or permitting requirement. 

Including ephemeral streams as jurisdictional waters constitutes a significant expansion 

of the definition as they are now explicitly regulated by Section 404 of the CWA.

...

The discussion in the proposed rule regarding ephemeral streams lacks sufficient clarity 

to enable the regulated community and professional practitioners to consistently 

differentiate between natural ephemeral streams and erosional features that occur in 
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189

different ecoregions of the U.S. Erosional features can be the result of past land use 

practices employed between the mid-20th century and the present day. These erosional 

features may have adverse influence on the conditions downstream which may be 

improved using modern design criteria for vegetated swales and channels. Therefore, 

clarification is needed to assist field practitioners in differentiating between ephemeral 

streams that would be considered tributaries under the proposed revisions. There should 

be very clear guidance in the rule as to what constitutes an ephemeral stream as 

contrasted with erosional features, particularly in light of the significant nexus 

requirements of the Rapanos guidance jointly issued by the USACE and EPA in response 

to the Supreme Court's plurality decision in Rapanos v. USACE.

The specific inclusion of ephemeral streams and the specific exclusion of upland ditches, 

gullies, rills, and non-wetland swales create confusion and potential risk for our clients as 

the interpretation in delineating these features can overlap. The intent of the new rule is to 

provide clarity and predictability to determinations of jurisdiction, yet this proposed 

definition of waters of the U.S. still remains uncertain. These proposed changes could 

create significant additional review and revision of delineations, design, planning, and 

permitting scenarios. (p. 3-4)

Agency Response: The longstanding regulatory definition of “waters of the United 

States” included “tributaries” without any limitations regarding volume or duration 

of flow. The December 2008 Guidance on post-Rapanos implementation noted that 

tributaries that flow only in direct response to rainfall are subject to the CWA if 

they have a significant nexus to a downstream traditional navigable water. 

Regulations addressing water quality standards for waters of the United States 

provide that states may modify standards for streams with natural ephemeral flow 

but may not declare an ephemeral stream non-jurisdictional altogether. See, e.g., 40 

CFR § 131.10(g)(2). See summary response for “Relevance of Flow Regime” above, 

particularly the subsection on jurisdiction over intermittent and ephemeral waters. 

Section VII of the Technical Support Document discusses the science supporting the 

agencies’ conclusion that all waters that meet the definition of “tributary” and that 

are not excluded in paragraph (b) have a significant nexus either individually or in 

the aggregate with traditional navigable waters, interstate waters and the territorial 

seas. 

GBMC & Associates (Doc. #15770)

8.228 ...The scientific literature reviewed and synthesized by the ORD included numerous 

papers addressing connectivity of intermittent and ephemeral streams to traditionally 

navigable waters. While the research provided support that intermittent and ephemeral 

streams can have "some measure of significance for connection to downstream water 

quality" as proposed by Justice Kennedy, it is hard to see that it provided justification that 

all ephemeral streams contain a significant nexus to downstream waters. Much of the 

literature lumps intermittent and ephemeral streams into a single category such as small 

streams or headwater streams and do not differentiate the specific functions of ephemeral 

streams. Thomas C. Winter, in his article titled The Role of Tround Water in Generating 

Streamflow in Headwater Areas and in Maintaining Base Flow, states that "nearly all 

streams need to have some contribution from ground water in order to provide reliable 
Clean Water Rule Response to Comments – Topic 8: Tributaries

190

habitat for aquatic organisms". Lack of a ground water connection to many ephemeral 

streams would not provide reliable habitat for aquatic organisms based on this statement. 

The literature often references the function of small/headwater wetted streams in 

providing habitat for aquatic invertebrates and nutrient transformations/spiraling. In the 

paper Ecological Linkages Between Headwaters and Downstream Ecosystems: Transport 

of Organic Matter, Invertebrates, and Wood Down Headwater Channels by Whipfli 

et.al., headwaters and headwater streams are defined as "small (usually <1m wide) wetted 

channels, and typically containing no fish, usually because of the lack of suitable habitat 

or the presence of fish migration barriers, but are fluvially connected to downstream 

water bodies that do". The upper reaches of many ephemeral streams only contain water 

for a few hours to a few days following a rain event and likely do not serve the function 

of providing suitable habitat, nor do they provide sufficient retention time for nutrient 

transformations or significant retention. (p. 2-3)

Agency Response: Providing habitat for aquatic organisms and conditions 

amenable for nutrient spiraling are only two of many potential functions of 

ephemeral and intermittent streams. Section VII of the Technical Support 

Document discusses the science supporting the agencies’ conclusion that ephemeral 

and intermittent tributaries significantly affect the chemical, physical or biological 

integrity of traditional navigable waters, interstate waters and the territorial seas. 

Thus, the agencies conclude that all waters that meet the definition of “tributary” 

and that are not excluded in paragraph (b) have a significant nexus either 

individually or in the aggregate with these downstream waters. 

8.229 4. The proposed rule makes several statements indicating that Intermittent streams and 

ephemeral streams will be treated the same, as they share similar functions in relation to a 

finding of significant nexus (Sec.II.C.2 and Sec.III.F.) This is far from the truth in many 

watersheds. Intermittent157 streams have flow at least seasonally and generally have 

sustained perennial pools during a normal climatic year. Ephemeral158 streams only have 

flow for a few days (at most) following a rainfall run-off event and do not have sustained 

perennial pools. This major difference precludes the development of significant aquatic 

habitat and aquatic communities in ephemeral streams. This reality also precludes 

significant chemical exchange from occurring in the channel, that is cited so frequently in 

the proposed rule as affecting the "chemical integrity" of waters listed in (a)(1) Through 

(a)(3). In many ephemeral streams, and particularly in those in moderate to high slope 

land surfaces, the travel time is too great for any substantial chemical exchange to occur. 

Ephemeral streams primary functions are water and sediment transport, not aquatic life or 

chemical exchange. These primary functions are easily replaced by whatever drainage 

pathways the stream might find should a headwater ephemeral stream be omitted from 

the landscape. For example, in a common development project (which the 404 program is 

designed to regulate) where an ephemeral stream channel is filled, the water volume on 

the site is still present, and will still need to be controlled through site drainage features 

 

157 North Carolina Department of Environmental and Natural Resources.

http://portal.ncdenr.org/web/wq/swp/ws/401/waterresources/faqs#What_is_a_stream_

158 Ephemeral Stream." Merriam-Webstercom. Merriam-Webster, n.d. Web. 10 Oct. 2014. 

http://www.merriamwebstercom/dictionary/ephemeral stream>.
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191

that might include naturally allowing the water to find its way to the next closest stream 

channel, creation of man-made drainage ditches to reroute the water flow or other 

relevant storm water best management practices. Any of these drainage controls, and 

others not mentioned, easily replaces the uses (water and sediment transport) lost by 

elimination of the ephemeral stream. We request that the agencies differentiate between 

intermittent and ephemeral streams, that ephemeral streams be more clearly defined and 

that they be treated differently in the significant nexus determination. Many ephemeral 

streams, if not all, should be excluded from Section 404 jurisdictional by definition; as 

they do not have functions that would be lost should the stream channel be eliminated. 

Redefining ephemeral streams in this way will provide the clarity and improved program 

efficiency that the agencies desire and would not be expected to cause a significant 

adverse impact to TNWs. (p. 3-4)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

the legality of asserting jurisdiction over ephemeral waters. Section I of the 

Technical Support Document discusses the legal basis of the final rule, including 

consistency with the statute and Supreme Court decisions. Section VII of the 

Technical Support Document discusses the science supporting the agencies’ 

conclusion that all waters that meet the definition of “tributary” and that are not 

excluded in paragraph (b), have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. 

Federal Water Quality Coalition (Doc. #15822.1)

8.230 3. Evolution of the expansion of “tributary” jurisdiction.

The agencies did not originally assert jurisdiction under the CWA over ephemeral water 

features. In fact, their assertion of authority over ephemeral water is relatively recent. In 

1975, the preamble to the Corps’ interim final regulations specified that the upstream 

limit of jurisdiction is the headwaters, or point where average annual stream flow is five 

cubic feet per second.159 In 1977, the preamble to the final Corps regulations specified 

that jurisdiction extends to the entire surface tributary system.160 In 1994, the Corps 

Baltimore District issued a guidance letter specifying that ephemeral waters act as rain 

gutters, conveying water for a brief period of time following rain events. As such, they do 

not ordinarily develop an ordinary high water mark that would indicate they are part of a 

tributary system. Consequently, they were not regulated.161 However, in 2000, the Corps 

Nationwide Permits preamble specified that federal jurisdiction extends to ephemeral 

streams, provided they have an ordinary high water mark, overturning the Baltimore 

District’s presumption that ephemeral streams would not have an ordinary high water 

 

159 40 Fed. Reg. 31,320, 31,321 (July 25, 1975).

160 42 Fed. Reg. at 37,129.

161 Branch Guidance Letter, COE, Baltimore District, CENAB-OP-R, No.95-01, Oct. 17, 1994 (“Project Managers

are frequently required to determine the upstream limits of regulatory jurisdiction, including differentiating between

intermittent streams, which are regulated (33 CFR § 328.3(a)(3)), and ephemeral streams, which are not regulated.”)

(attached). This has been relied upon by numerous entities. See attached Montgomery County, MD guidance.
Clean Water Rule Response to Comments – Topic 8: Tributaries

192

mark.162 This assertion of jurisdiction led to abuses.163 Moreover, even though the Corps 

took this position in 2000, as discussed below, both the plurality and Justice Kennedy 

were not persuaded that an ordinary high water mark is a basis for jurisdiction.

The agencies also did not assert authority over ditches until relatively recently. In fact, 

the 1977 Corps definition of waters of the U.S. expressly excluded “manmade nontidal 

drainage and irrigation ditches excavated on dry land” from the definition of tributaries, 

stating that they “are not considered waters of the United States under this definition.” 33 

C.F.R. § 323.2(a)(3)(1977).164

In addition, the agencies have not traditionally asserted jurisdiction over water based on 

subsurface connections that are not diversions of former surface streams and have never 

done so categorically.165 For example, a 2001 policy issued by the Galveston District of 

the Corps of Engineers states that it does not use groundwater connections to establish 

jurisdiction.166 Moreover, directly contradicting the position in the proposed rule, in 

litigation, EPA has taken the position that identification of a connection to surface water 

via groundwater must be made on a site-specific basis.167

Yet the agencies now claim that all waters proposed to be defined as “tributaries,” 

including ephemeral waters, ditches, and waters with subsurface connections, have a 

“significant nexus” to navigable or interstate waters or the territorial sea and therefore are 

per se jurisdictional. This is an expansion of jurisdiction.

This proposed expansion of the definition of tributary has created tremendous uncertainty 

regarding the status of land that exhibits erosion features from wind or water even if dry 

for many years, the status of water conveyance systems, the status of water drainage 

systems, the status of ephemeral streams, and the status of features that have no 

continuous surface connection to navigable water. (p. 12-13)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

 

162 65 Fed. Reg. 12,818, 12,823 (Mar. 9, 2000).

163 For example, in a March 30, 2004, hearing of the Water Resources and Environment Subcommittee of the House

Committee on Transportation and Infrastructure on “Inconsistent Regulation of Wetlands and Other Water,” one 

witness testified that a Corps official used a 25-year old skidder rut to connect a wetland to a ditch to a stream.

House Doc. No. 108-58 at 81-82 (attached). Under the proposed rule, Corps officials would remain free to conclude 

that a skidder rut has an OHWM and therefore is part of the tributary system.

164 “We have adopted the suggestion of many commenters that we incorporate into our definition (and not in the

Preamble as we did in 1975) the statement that nontidal drainage and irrigation ditches that feed into navigable 

waters will not be considered ‘waters of the United States’ under this definition. To the extent that these activities 

cause water quality problems, they will be handled under other programs of the FWPCA, including Sections 208 and 

402.” 42 Fed. Reg. at 37127. Even though the preamble stated that the regulations were merely reorganized, the

1986 definition of waters of the U.S. moved this clarification from rule language to preamble language and reserved 

the right to regulate ditches on a case by case basis. 51 Fed. Reg. at 41217.

165 Waters and Wetlands, Corps of Engineers Needs to Evaluate Its District Office Practices in Determining

Jurisdiction (GAO-04-297), at 24 (discussing using connections through subsurface closed conveyances to establish 

jurisdiction only if the pipe replaced a historic stream) (attached). No such limitation appears in the proposed rule.

166 Adjacent/Isolated Criteria, Galveston District Policy Number 01-001 (attached).

167 Conservation Law Foundation et al. v U.S. EPA, et. al., Case No. 1:10-cv-11455-MLW, Memorandum in 

Support of Defendants’ Motion for Summary Judgment, at 20-21 (noting that a hydrological connection to surface 

water via groundwater is a site-specific determination) (attached).
Clean Water Rule Response to Comments – Topic 8: Tributaries

193

the legality of asserting jurisdiction over ephemeral waters. Section I of the 

Technical Support Document discusses the legal basis of the final rule, including 

consistency with the statute and Supreme Court decisions. The agencies’ position in 

regard to tributaries is rooted in a science-based conclusion that such waters have a 

significant nexus either individually or in the aggregate with traditional navigable 

waters, interstate waters, and the territorial seas. Section VII of the Technical 

Support Document discusses the science supporting the agencies’ conclusion that all 

waters that meet the definition of “tributary” and that are not excluded in 

paragraph (b) have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Paragraph 

(b) of the final rule outlines numerous exclusions for features that will not be waters 

of the United States, including most ditches that are not relocated tributaries or 

excavated in tributaries.

8.231 Under the Rapanos case, a showing that regulation of a tributary is necessary to protect 

navigable water must be based whether the flow in the tributary is “relatively permanent” 

and whether that flow could affect water quality. The plurality decision determined that 

flow must be relatively permanent to have any impact on downstream navigable water. 

Justice Kennedy added a requirement that not just any impact was sufficient; it must be a 

significant impact. As discussed above, Supreme Court precedent requires that both tests 

be met for a non-navigable water to be jurisdictional under the CWA.

Applying that test to “tributaries,” tributaries would be defined as waters of the U.S. 

based on whether a natural channel of water that maintains flow even when it is not 

raining such that it is “relatively permanent.” In addition, the tributary must be capable of 

transporting pollution to a navigable water such that it could have a significant impact on 

the navigable water. This legal basis for this recommendation is the fact that the purpose 

of the CWA is to protect navigable waters from pollution. The technical basis would be 

an evaluation of the permanence of the flow and whether that flow could carry pollutants 

to a navigable water in a particular geographic area.168 This definition would not extend 

to water that goes underground, so the agencies would not need to make arbitrary 

decisions about the distance groundwater can travel, or how many years can elapse before 

groundwater is recharged to surface water, and remain a “tributary.” The CWA does not 

apply to groundwater, shallow or not. Water that becomes groundwater loses its status as 

a water of the U.S. Thus, non-navigable water that flows on the surface before it becomes 

groundwater cannot be considered a water of the U.S. These distinctions will do much to 

increase the clarity of a proposed rule.

Under this definition, identification of a tributary would not be based on U.S. Geological 

Survey maps, aerial photography, or remote sensing information, as proposed by the 

agencies. Instead, it would be based on quantitative information about flows, adding 

 

168 The agencies’ subjective determination that an OHWM can be discerned is not an appropriate surrogate. In 2003, 

Robert Pierce reviewed the reliability of the use of the term “OHWM” and other terms that the Corps uses to 

determine the limits of its jurisdiction in inland landscapes and identified technically-based alternative concepts that 

would be more appropriate and defensible. He concluded that: “The COE needs to assess what a reasonable level of 

flow is necessary to have an effect on a navigable waterbody before it concludes that any particular landscape 

feature that exhibits an OHWM is jurisdictional.” See Pierce, supra n. 126, at 22.
Clean Water Rule Response to Comments – Topic 8: Tributaries

194

certainty and clarity and greatly reducing arbitrary differences among jurisdictional 

determination[.] (p. 64-65)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

“Requirement of Contribute Flow.”

8.232 B. Focus on Water Bodies, Not Overland Flow, Point Source Conveyances, or Water 

Used for Municipal, Industrial, or Commercial Purposes.

The agencies claim the authority to identify what waters are “the focus of the CWA.” 79 

Fed. Reg. at 22218. However, they do not explain what that focus is. We urge the 

agencies to recognize that the CWA is focused on the protection of the quality of 

navigable waters and is not focused on the use of land or water. Further, not all water is a 

water of the United States even if it can convey pollutants to navigable water. To 

facilitate future decision-making and promote certainty regarding when the CWA does 

and does not apply, the agencies should articulate the legal and policy rationales for 

identifying water that is not a “water of the U.S.”

1. Overland flow.

First, the agencies should clearly explain that the CWA does not regulate the overland 

flow of rain and snow melt. All overland runoff may eventually flow to a channel, but 

this water is considered a nonpoint source.169 It would not become part of the waters of 

the U.S. until it flows into a water of the U.S.

Applying this clarification, water that flows only in response to rain or snow melt would 

not be a water of the U.S. Thus, a reproposal would not need to define gullies and rills or 

distinguish them from an “ephemeral stream.” None of these features would be subject to 

federal jurisdiction.

... (p. 66-67)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

the legality of asserting jurisdiction over ephemeral waters. The definition of 

“tributary” in the final rule requires that flow must be of sufficient volume, 

frequency, and duration to create the physical characteristics of bed and banks and 

an OHWM. The rule includes ephemeral streams that meet the definition of 

tributary as waters of the United States, because the agencies determined that such 

streams provide important functions for downstream waters, and in combination 

with other protected tributaries in a watershed significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas. See also the summary response for Section 8.4. “Distinction 

between an ephemeral water and a non-jurisdictional gulley, rill or non-wetland 

swales.” Section VII of the Technical Support Document also discusses the 

 

169 Trustees for Alaska v. EPA, 749 F.2d 549, 558 (9th Cir.1984) (“[P]oint and nonpoint sources are not 

distinguished by the kind of pollution they create or by the activity causing the pollution, but rather by whether the 

pollution reaches the water through a confined, discrete conveyance.”).
Clean Water Rule Response to Comments – Topic 8: Tributaries

195

differences between rills and other non-jurisdictional erosional features and 

ephemeral tributaries that are waters of the United States.

Action United et al. (Doc. #18859)

8.233 We support the Agencies' proposal to define all tributaries as "waters of the United 

States," including headwaters and small streams that may only flow seasonally. 

Headwater streams provide most of the flow to downstream streams and rivers, and make 

up 59% of Pennsylvania's stream miles. Intermittent and ephemeral streams may only 

flow during parts of the year, but they support water quality in downstream waters by 

filtering pollutants and capturing nutrients and make up 25% of Pennsylvania's stream 

miles. These streams are also critical habitat for fish and other aquatic species.

Headwater and seasonal streams also feed the drinking water sources of 117 million 

Americans, including 8 million residents in Pennsylvania. Clarifying that all tributary 

streams, regardless of size or frequency of flow are covered under the Clean Water Act 

will restore protections to 10,720 miles of streams in Pennsylvania that 63% of our 

residents depend on for drinking water. (p. 2)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters. 

The definition of “tributary” in the final rule requires that flow must be of sufficient 

volume, frequency, and duration to create the physical characteristics of bed and 

banks and an OHWM. The rule includes ephemeral streams that meet the 

definition of tributary as waters of the United States, because the agencies 

determined that such streams provide important functions for downstream waters, 

and in combination with other protected tributaries in a watershed significantly 

affect the chemical, physical, and biological integrity of traditional navigable waters, 

interstate waters, and the territorial seas. 

Southern Nevada Home Builders Association (Doc. #3251)

8.234 The EPA's proposed rule change also contains several assumptions and definitional 

changes that will inarguably result in an expansion of jurisdiction. For example, the 

proposed rule assumes that all "tributaries" have a significant nexus to TNWs and/or 

other interstate waters and, therefore, constitute de facto "jurisdictional waters" subject to 

regulation under the CWA. The proposed rule change appears to make this assumption 

solely on the basis of the Connectivity Study and without any further site-specific 

analysis or consideration of the size, flow or location J of these areas classified as 

"tributaries". In addition, the term "tributaries" is so broadly defined that it nearly 

includes anything that carries any periodic water flows, including "man-altered and manmade" canals, ditches and other similar man-made waterways, all of which were 

previously not regulated under the CWA. (p. 2)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

the legality of asserting jurisdiction over ephemeral waters. The definition of 

“tributary” in the final rule requires that flow must be of sufficient volume, 

frequency, and duration to create the physical characteristics of bed and banks and 

an ordinary high water mark. If a water lacks sufficient flow to create such 
Clean Water Rule Response to Comments – Topic 8: Tributaries

196

characteristics, it is not considered “tributary” under this rule. Section VII of the 

Technical Support Document further discusses the science supporting the agencies’ 

conclusion that all waters that meet the definition of “tributary” and that are not 

excluded in paragraph (b), have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. For these reasons, the final rule does not require that a case-by-case 

determination be made regarding whether an ephemeral or tributary stream has a 

significant nexus to navigable waters. Instead, the case-by-case inquiry is whether 

or not the water under consideration meets the rule’s definition of “tributary” and 

is not excluded by paragraph (b). Section VII also specifically discusses man-made 

or man-altered tributaries and their effect on the physical, chemical and biological 

integrity of traditional navigable waters, interstate waters and the territorial seas. 

Man-made and man-altered tributaries, despite human manipulation, usually 

continue to have chemical, physical, or biological connections downstream and to 

serve important functions downstream. The rule’s conclusion that waters meeting 

the definition of “tributary” have a significant nexus is informed by EPA’s Office of 

Research and Development (ORD) Science Report (a peer-reviewed compilation 

and analysis of published peer-reviewed scientific literature summarizing the 

current scientific understanding of the connectivity of and mechanisms by which 

streams and wetlands, singly or in combination, affect the chemical, physical, and 

biological integrity of downstream waters). The agencies also must rely on their 

technical expertise and practical experience in implementing the CWA during a 

period of over 40 years. In addition, the agencies are guided, in part, by the 

compelling need for clearer, more consistent and easily implementable standards to 

govern administration of the CWA, including brighter lines where feasible and 

appropriate.

The Elm Group, Inc. (Doc. #9688)

8.235 The proposed rule considers all tributaries "waters of the United States" based on their 

ability to affect the biological, chemical, and/or physical quality of the downstream 

receiving waterbody regardless of their position in the watershed and flow characteristics 

(ephemeral versus perennial). However, the biological, chemical, and physical 

characteristics of the streams located in a shared watershed can differ significantly based 

on adjacent land uses and historic activities/use, and are not always a reflection of the 

upstream areas. As such, the new definition should allow for the exemption of some 

tributaries (i.e., ephemeral, small intermittent) based on a lack of similar biological, 

chemical, and physical characteristics and the absence of a significant connection 

(potential affect) to the downstream regulated waterbody. (p. 1)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters. 

The definition of “tributary” in the final rule requires that flow must be of sufficient 

volume, frequency, and duration to create the physical characteristics of bed and 

banks and an ordinary high water mark. If a water lacks sufficient flow to create 

such characteristics, it is not considered “tributary” under this rule. Section VII of 

the Technical Support Document further discusses the science supporting the 

agencies’ conclusion that all waters that meet the definition of “tributary” and that 
Clean Water Rule Response to Comments – Topic 8: Tributaries

197

are not excluded in paragraph (b), have a significant nexus either individually or in 

the aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. 

8.236 As currently defined in the new rule, a tributary that has defined bed/bank and a high 

water mark but no longer conveys water due to adjacent land use changes would be 

considered an ephemeral, regulated waterbody. Considering the ongoing changes in 

numerous watersheds and water resource management practices, the new rule should 

further clarify when and how frequently a stream/tributary needs to "contribute flow" to a 

downstream waterbody in order to have a significant impact on the receiving streams' 

chemical, biological, and physical quality. More specifically, ELM suggests a stream 

should be required to contribute flow for a period at least twice as long as the annual 

number of days of flow that is directly associated precipitation-driven surface water 

runoff events. Otherwise, the contributed flow during storm events will be dominated by 

surface runoff with little contribution of the biogeochemical processes in the area of 

runoff. (p. 1-2)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

“Requirement of ‘Contribute Flow’”. The definition of “tributary” in the final rule, 

like the proposed rule, requires that flow must be of sufficient volume, frequency, 

and duration to create the physical characteristics of bed and banks and an 

ordinary high water mark. If a water lacks sufficient flow, it is likely that these 

characteristics will not be maintained. The agencies recognize that land use changes 

can influence the amount of flow associated with receiving streams. These changes 

can be taken into account by field personnel when making jurisdictional 

determinations. Determinations of whether a water “contributes flow” are expected 

to be done in a manner similar to what has been practiced in the field for decades. 

This is why determinations of jurisdiction are done on a case by case basis based on 

the best information available and they are only valid for five years, to allow for 

changes in environmental conditions to shape the outcome over time. The final rule 

preamble discusses this process in greater length in Section IV.F.1. See also 

summary response 8.3 below. 

National Ready Mixed Concrete Association (Doc. #13956)

8.237 NRMCA is extremely concerned about the inclusion of ephemeral streams as waters of 

the U.S. These small features run for a short time, only after rain events, and their 

inclusion is an enormous expansion of jurisdiction. In Kansas, it would increase the 

amount of jurisdictional stream miles more than 400%, from 32,000 miles to 134,000 

miles while having a negligible impact on environmental quality.170 Because the agencies 

use the term ‘‘water’’ and ‘‘waters’’ in the proposed rule not just to “refer solely to the 

water contained in these aquatic systems, but to the system as a whole including 

 

170 Letter to Nancy Stoner, Acting Assistant Administrator for Water, U.S. Environmental Protection Agency from 

Sam Brownback, Governor of Kansas (July 14, 2011).
Clean Water Rule Response to Comments – Topic 8: Tributaries

198

associated chemical, physical, and biological features, ”171 including ephemeral streams 

will inevitably result in regulating land use as they are dry most of the time. (p. 10)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

the legality of asserting jurisdiction over ephemeral waters. Section I of the 

Technical Support Document discusses the legal basis of the final rule, including 

consistency with the statute and Supreme Court decisions. The agencies’ position in 

regard to tributaries is rooted in a science-based conclusion that such waters have a 

significant nexus either individually or in the aggregate with traditional navigable 

waters, interstate waters, and the territorial seas. Section VII of the Technical 

Support Document discusses the science supporting the agencies’ conclusion. 

Building Industry Association of Greater Louisville (Doc. #16449)

8.238 The proposed rule redefines and expands the reach of the Clean Water Act (CWA) 

jurisdiction in that the rule:

 More broadly reaches inclusion of ephemeral waterways that may flow only 

intermittently and indirectly over a long distance to reach a navigable water;

... (p. 1)

Agency Response: See summary response for section 8.1.1. Also, Section I of the 

Technical Support Document discusses the legal basis of the final rule, including 

consistency with the statute and Supreme Court decisions. The agencies’ position in 

regard to tributaries is rooted in a science-based conclusion that such waters have a 

significant nexus either individually or in the aggregate with traditional navigable 

waters, interstate waters, and the territorial seas. Section VII of the Technical 

Support Document discusses the science supporting the agencies’ conclusion. 

National Association of Home Builders (Doc. #19540)

8.239 This overbroad streams is an expansion of jurisdiction. The definition of tributaries will 

sweep in waters and features well beyond the reach of the Agencies' CWA authority and 

any commonsense definition of the word.

1. Asserting Categorical Jurisdiction over all Tributaries is Legally 

Indefensible.

The Agencies' categorical assertion of jurisdiction over all tributaries is inconsistent with 

the Rapanos Court and inappropriately reverts back to regulating any mere hydrologic 

connection.

a. The Tributary Definition Contravenes the Supreme Court in Rapanos. 

Both the Rapanos plurality and Justice Kennedy raised concerns about far-reaching 

jurisdiction over features distant from navigable waters and carrying insignificant 

volumes of flow. The plurality even went so far as to chastise the Corps for extending 

 

171 Footnote 3 – 79 FR 22191.
Clean Water Rule Response to Comments – Topic 8: Tributaries

199

jurisdiction to "'ephemeral streams,' 'wet meadows,' storm sewers and culverts, 

'directional sheet flow during storm events,' drain tiles, man-made drainage ditches, and 

dry arroyos in the middle of the desert,172"n and in doing so, stated, "the Corps has 

stretched the term 'waters of the United States' beyond parody."173 Justice Kennedy 

similarly criticized the Agencies' "existing standard" for tributaries which "deems a water 

a tributary if it feeds into a traditional navigable water (or tributary thereof) and possesses 

and ordinary high water mark" because this definition "leave[s] wide room for regulation 

of drains, ditches, and streams remote from any navigable-in-fact water and carrying only 

minor volumes toward it."174 Indeed, Justice Kennedy noted, "the dissent would permit 

federal regulation whenever wetlands lie alongside a ditch or drain, however remote or 

insubstantial, that eventually may flow into traditional navigable waters. The deference 

owed the Corps' interpretation of the statute does not extend so far."175

Despite these clear statements and contrary to the limits of CWA jurisdiction recognized 

by the Rapanos plurality and Justice Kennedy’s concurrence, the proposed definition of 

tributary allows for per se jurisdiction over features with remote proximity and tenuous 

connections to traditional navigable waters, including ephemeral drainages. Indeed, just 

like the Agencies’ previous standard that the Supreme Court considered too far-reaching, 

the Agencies’ new definition allows for categorical regulation of conveyances, drains, 

ditches, and ephemeral streams that have little or no relationship to traditional navigable 

waters. Clearly, the proposed rule’s definition of tributary is over broad and ignores the 

limits of the CWA recognized by the Supreme Court. In the words of Justice Scalia, 

“[t]he plain language of the statute simply does not authorize this ‘Land is Waters’ 

approach to federal jurisdiction.” Yet with the over broad definition of tributary, the 

Agencies are again attempting to stretch the definition of “waters of the United States” 

beyond parody. (p. 55-56)

Agency Response: Compared to the historic scope of the existing rule, the final 

rule is narrower; compared to agency practice in light of guidance issued after 

SWANCC and Rapanos, the final rule is generally broader, but not broader than 

the existing rule. See summary response for "Relevance of Flow Regime" above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

the legality of asserting jurisdiction over ephemeral waters. Section I of the 

Technical Support Document discusses the legal basis of the final rule, including 

consistency with the statute and Supreme Court decisions. The agencies' position in 

regard to tributaries is rooted in a science-based conclusion that such waters have a 

significant nexus either individually or in the aggregate with traditional navigable 

waters, interstate waters, and the territorial seas. Section VII of the Technical 

Support Document discusses the science supporting the agencies' conclusion. 

8.240 b. Basing the Tributary Definition on the Contribution of Flow Inappropriately 

Reverts Back to Regulating any Mere Hydrologic Connection - a Theory Rejected 

by both the Rapanos Plurality and Justice Kennedy. 

 

172 Rapanos, 547 U.S. at 734

173 See id at 734.

174 See id at 781.

175 Id. at 778, 779.
Clean Water Rule Response to Comments – Topic 8: Tributaries

200

The proposed rule designates any water a tributary and per se jurisdictional if it 

"contributes flow, either directly or through another water," to a traditional navigable 

water, interstate water territorial sea, or impoundment of any of those three. By defining 

any water as jurisdictional by rule if it has a bed, bank, and an ordinary high water mark 

(OHWM) and contributes flow to such a jurisdictional water, the Agencies have 

disregarded the Supreme Court ruling in Rapanos in which five Justices rejected the 

notion that CWA jurisdiction applies to any water if it possesses a hydrologic connection 

to a traditional navigable water. Justice Kennedy opined, ". . . mere hydrologic 

connection should not suffice in all cases; the connection may be too insubstantial far the 

hydrologic linkage to establish the required nexus with navigable waters as traditionally 

understood.176 He continued, “...a...ditch could...be located many miles from any 

navigable-in-fact water and carry only insubstantial flow towards it. A more specific 

inquiry, based on the significant nexus standard, is therefore necessary."177 The Rapanos 

plurality note "relatively continuous flow is a necessary condition for qualification as a 

'water,' not an adequate condition."178 The concurring Justices may not have all agreed on 

the test required to determine jurisdiction, but they did agree that jurisdiction should not 

be based on the presence a hydrologic connection in and of itself. The Agencies must 

honor this commonality in the proposed rule.

By defining tributary as a feature that "contributes flow," the Agencies ignore the tests 

developed by the Supreme Court in Rapanos and wrongfully revert back to regulating 

any hydrologic connection. Furthermore, the Agencies disregard Justice Kennedy's 

"significant nexus" test by making all connections categorically jurisdictional. Such a 

broad overreach is impermissible. (p. 56)

Agency Response: The definition of “tributary” in the final rule specifically 

requires physical indicators of bed and bank and an ordinary high water mark in 

order for a feature to be considered a tributary. The simple fact that a feature 

might “contribute flow” to a jurisdictional water does not automatically make that 

feature a tributary. Furthermore, the exclusions outlined in paragraph (b) of the 

final rule are broad and include most ditches that are not actually relocated 

tributaries or excavated in tributaries. See summary response for “Relevance of 

Flow Regime” above, particularly subsections on jurisdiction over intermittent and 

ephemeral waters, the legality of asserting jurisdiction over ephemeral waters and 

the requirement of “contribute flow.” Section I of the Technical Support Document 

discusses the legal basis of the final rule, including consistency with the statute and 

Supreme Court decisions. Section VII of the Technical Support Document discusses 

the science supporting the agencies’ conclusion that all waters that meet the 

definition of “tributary” and that are not excluded in paragraph (b) have a 

significant nexus either individually or in the aggregate with traditional navigable 

waters, interstate waters, and the territorial seas. 

8.241 2. Lacking Scientific Support, the Agencies Wrongly Assert that All Tributaries 

have a Significant Nexus to Downstream Waters.

 

176 Id. at 784,785.

177 Id. at 786.

178 ld at 736 n.7 (original emphasis).
Clean Water Rule Response to Comments – Topic 8: Tributaries

201

The Agencies assert that all tributaries have a significant nexus to traditional navigable 

waters: “With this proposed rule, the Agencies conclude, based on existing science and 

the law, that a significant nexus exists between tributaries . . . and the traditional 

navigable waters, interstate waters, and the territorial seas . . . Consequently, this rule 

establishes as ‘waters of the United States,’ all tributaries . . . of the traditional navigable 

waters, interstate waters, and the territorial seas . . . it has been determined that as a 

category, [tributaries] have a significant nexus and thus are ‘waters of the United 

States.”179 The authors of the Connectivity Report, however, recognize the decreasing 

impact a water has on downstream waters with increasing distance between those waters, 

stating, “all else being equal, materials traveling shorter distances could enter the river 

with less transformation or dilution [than materials traveling longer distances],”180 and 

continuing, “[h]ydrologic connectivity between streams and rivers can be a function of 

the distance between the two water bodies.”181 Further, Justice Kennedy recommended 

the Corps consider the distance of a tributary to a navigable water when making a 

jurisdictional determination: “ . . . the Corps may choose to identify categories of 

tributaries that . . . due to their . . . proximity to navigable waters . . . are significant 

enough that wetlands adjacent to them are likely . . . to perform important functions for 

an aquatic system incorporating navigable waters.”182

Dr. Mark Murphy of EPA’s SAB also raised concerns about the assertion that all 

tributaries are per se jurisdictional, stating, “the inclusion by rule of all tributaries to 

traditional navigable waters is not scientifically justified by the published literature, the 

Connectivity report or the SAB review. Inclusion by rule violates the conclusion of the 

SAB review that connectivity exists as a gradient of causal phenomena that operate 

variably over flowpaths, and result in consequential disturbances in the watershed.”183 In 

other words, Dr. Murphy recognizes that not all tributaries have the same impact on 

downstream waters. Rather, connectivity between tributaries and traditional navigable 

waters exists on a gradient from insubstantial to significant. Indeed, an ephemeral stream 

in Arizona that only flows as a trickle several hours a year does not have the same 

chemical, physical, and biological effects on the Colorado River as does the Little 

Colorado River, a perennial tributary contributing most of the flow to the Colorado.184

(See Section VI. b. i. 4. for a more detailed discussion of the Agencies’ failure to 

recognize connectivity and significant nexus along a gradient).

Despite suggestions put forth by a United States Supreme Court Justice, an SAB panelist, 

and peer-reviewed science cited by a cadre of ecologists, the Agencies ignore the 

decreasing impact a water has on downstream waters with increasing distance between 

those waters. The proposed rule states, “[t]ributaries have vitally important effects on the 

physical integrity of (a)(1) through (a)(3) waters, contributing not only the majority of 

flow in these waters but affecting the structure of the waters. These effects occur . . . even 

 

179 79 Fed. Reg. at 22,193.

180 Draft Connectivity Report at 1-5.

181 Id. at 3-41.

182 Rapanos, 547 U.S. at 781 (emphasis added).

183 8/14/14 SAB Comments on the Proposed Rule at 63.

184 Benke, A.C., and C.E. Cushing. Editors. Rivers of North America, Burlington, MA: Elsevier Academic Press, 

2005. Print.
Clean Water Rule Response to Comments – Topic 8: Tributaries

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when the tributaries are significant distances from the (a)(l) through (a)(3) water."185 The 

proposed rule continues, "[t]ributaries that . . . are a substantial distance from the nearest 

(a)(l) through (a)(3) water . . . are essential components of the tributary network and have 

important effects on the chemical, physical, and biological integrity of (a)(l) through 

(a)(3) waters . . ."'186 Indeed, ,the Agencies have ignored the science in an aggressive 

effort to sweep all features with a bed, a bank, and an OHWM that contribute flow -

regardless of magnitude, duration, and frequency - under the jurisdiction of the CWA. 

This is illogical and cannot be supported. (p. 57-58)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters, 

legality of asserting jurisdiction over ephemeral waters and requirement of 

“Contribute Flow.” The definition of “tributary” in the final rule emphasizes the 

importance of flow. Flow must be of sufficient volume, frequency, and duration to 

create the physical characteristics of bed and banks and an ordinary high water 

mark. If a water lacks sufficient flow to create such characteristics, it is not 

considered “tributary” under this rule. Section VII of the Technical Support 

Document further discusses the science supporting the agencies’ conclusion that all 

waters that meet the definition of “tributary” and that are not excluded in 

paragraph (b), have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. While the 

agencies’ conclusion is informed by the Science Report, the agencies also must rely 

on their technical expertise and practical experience in implementing the CWA 

during a period of over 40 years. In addition, the agencies are guided, in part, by the 

compelling need for clearer, more consistent and easily implementable standards to 

govern administration of the CWA, including brighter lines where feasible and 

appropriate.

8.242 5. The Agencies Fail to Define Key Terms and Describe Key Methods Necessary to 

Determine Whether or not a Water Meets the Tributary Definition, Thereby 

Increasing Regulatory Uncertainty.

The Agencies claim that the proposed rule will increase clarity as to the scope of “waters 

of the United States” protected under the CWA. However, they have failed to define three 

key terms used to determine whether or not a water meets the tributary definition and if 

that water is jurisdictional by rule. By not defining “bank,” “flow,” and “another water” 

the Agencies have not increased clarity regarding the jurisdictional scope of the CWA, 

yet have provided more hooks with which to claim authority.

a. The Agencies Fail to Define Critical Parameters Needed to Identify the 

“Bank” of a Tributary.

In addition to the challenges associated with identifying the OHWM, NAHB finds it 

troublesome that no parameters or bright lines are identified to objectively quantify the 

point at which a “bank” occurs and a water exhibits one of the three geomorphic 

characteristics necessary to meet the definition of tributary. For instance, the proposed 

 

185 79 Fed. Reg. at 22,205 (emphasis added).

186 Id. at 22,206 (emphasis added).
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rule explicitly excludes “non-wetland swales” from jurisdiction and differentiates nonjurisdictional non-wetland swales from jurisdictional tributaries in that non-wetland 

swales are “non-channelized, shallow trough-like depressions that carry water mainly 

during rainstorms or snowmelt” – a definition that could possibly be used to define many 

of the “tributaries” the Agencies seek to regulate.187 According to the proposal, however, 

a non-channelized “swale” becomes a “tributary” at the point at which it becomes 

channelized; that is, when it exhibits a bank. While the Agencies claim the proposed rule 

provides clarity to regulated entities as to whether individual water bodies are 

jurisdictional, without a clearly defined threshold for bank, the point at which a nonjurisdictional swale becomes a jurisdictional tributary is left to speculation (Fig. 4). This 

will add unnecessary regulatory confusion, and make it difficult for home builders and 

others in the regulated community to know with certainty whether or not a water is under 

federal jurisdiction. At a minimum, the Agencies must define bank within the tributary 

definition in order to provide any semblance of clarity.

Figure 4: The Agencies assert that features with a bed, a bank, and an OHWM are tributaries and categorically 

jurisdictional. Non-wetland swales that lack a bank, however, are explicitly excluded from CWA jurisdiction. 

Without defining the point at which a geomorphic feature exhibits a bank, the Agencies have not provided clarity as 

to whether a feature is a jurisdictional tributary or a non-jurisdictional non-wetland swale.

(p. 63-64)

Agency Response: Agency response: The preamble of the final rule defines bed 

and banks to mean the substrate and sides of a channel between which flow is 

confined. The banks constitute a break in slope between the edge of the bed and the 

surrounding terrain, and may vary from steep to gradual. For a discussion of the 

agencies’ response to comments regarding clarity for definitions, see Compendium 

 

187 Id. at 22,219.
Clean Water Rule Response to Comments – Topic 8: Tributaries

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14.3 and associated summary essay and individual responses. See also the summary 

response for “Relevance of Flow Regime” above.

8.243 b. The Agencies Fail to Define “Flow” and Associated Ecologically Critical 

Parameters.

In addition to the case law inconsistencies related to the contribution of flow, the 

tributary definition fails to describe and define critical scientific streamflow parameters. 

Flow, a “master variable” defining stream structure and function188 and arguably one of 

the most well studied parameters in lotic ecology, is undefined. In one of the most oftcited papers in stream ecology, entitled “The Natural Flow Regime,” Dr. LeRoy Poff and 

colleagues state, “streamflow quantity and timing are critical components of water 

supply, water quality and the ecological integrity of river systems. Indeed, streamflow, 

which is strongly correlated with many critical physicochemical characteristics of rivers, 

such as water temperature, channel geomorphology, and habitat diversity, can be 

considered a master variable that . . . regulates the ecological integrity of flowing water 

systems.”189 Dr. Poff et al. describe a widely accepted framework highlighting the central 

importance of flow magnitude, frequency, duration, timing, and rate of change on the 

ecological integrity of stream ecosystems (Fig. 5).

 

188 Poff, N.L., J.D. Allan, M.B. Bain, J.R. Karr, K.L. Prestegaard, B.D. Richter, R.E. Sparks, J.C. Stromberg. 1997. 

The Natural Flow Regime. BioScience, Vol. 47(11):769-784.

189 Id at 769.
Clean Water Rule Response to Comments – Topic 8: Tributaries

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Figure 5: The "natural flow regime" framework highlighting the central importance of flow magnitude, frequency, 

duration, timing, and rate of change on the ecological integrity of stream ecosystems.190

Streamflow is commonly described in lotic ecology according to the flow parameters Dr. 

Poff and his colleagues described in 1997. Yet, the proposed rule - which the Agencies 

purport to be based on the "best available science"191- provides no descriptors to define 

flow. In Rapanos, Justice Kennedy suggested the Corps consider flow volume when 

determining the jurisdiction of tributaries: “ . . . the Corps may choose to identify 

categories of tributaries that, due to their volume of flow . . . are significant enough that 

wetlands adjacent to them are likely . . . to perform important functions for an aquatic 

system incorporating navigable waters.”192 Yet the Agencies have failed to heed this 

advice.

Flow parameters are critical toward determining the degree to which a water significantly 

affects the chemical, physical, and biological integrity of traditional navigable waters.193

For example, the greater the magnitude (i.e., discharge volume) of flow, the longer the 

duration of flow, and the greater the frequency of flow between a water and a traditional 

navigable water, the greater the probability that water will significantly affect the 

chemical, physical, and biological integrity of a traditional navigable water. Indeed, 

EPA's SAB included a figure describing this phenomenon in its final review of the draft 

Connectivity Report (see Fig. 2 above), where it depicts the decreasing probability of a 

water to affect a downstream water as the magnitude, duration, and frequency of flow 

between those waters decreases. Yet, the draft Connectivity Report and the proposed rule 

 

190 Source: id. at 770.

191 79 Fed. Reg. at 22,202.

192 Rapanos, 547 U.S. at 781 (emphasis added).

193 Poff et al. at 770; Allan. J.D. and M. M. Castillo. Stream Ecology, 2nd ed . New York: Springer, 2007. Print.
Clean Water Rule Response to Comments – Topic 8: Tributaries

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both interpret hydrologic connectivity among waters as binary - that is either connected 

or not connected - when connectivity and subsequent chemical, physical, and biological 

impacts between waterbodies occur along a gradient.194

By failing to define flow and associated hydrologically and ecologically critical 

parameters, including magnitude, duration, and frequency, the Agencies wrongfully 

consider all tributary flows to be equal in their ability to significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters. In reality, hydrologic 

connectivity and the degree of subsequent physicochemical impacts on downstream 

waters exist along a gradient from insubstantial to significant. This gradient must be 

reflected in the approach the Agencies use to determine those waters that are "waters of 

the United States" and those that are not. (See Section VI. b. i. 4. for further discussion of 

the gradient of connectivity and, in turn, significant nexus). (p. 64-66)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly the subsection on jurisdiction over intermittent and ephemeral waters.

The final rule relies on physical characteristics rather than a particular flow regime

to identify tributaries with a significant nexus, either individually or in the 

aggregate, with traditional navigable waters, interstate waters, and the territorial

seas. The rule’s definition of tributary requires two physical indicators of flow: 

there must be a bed and banks, and an additional indicator of OHWM. These 

physical indicators of water flow are only created by sufficient and regular intervals 

of flow. By grounding the definition of “tributary” in the final rule to the above 

referenced specific physical features, the agencies believe that confusion regarding 

whether a feature is a “tributary” or a non-jurisdictional “erosional feature” will be 

minimal. See also summary response under section 8.4: Distinction between 

ephemeral water and a non-jurisdictional gulley, rill or non-wetland swale.

8.244 i. The Agencies Fail to Describe Methods to Quantify Contributions of Flow to an 

(a)(l) through (4) Water.

To meet the definition of tributary, and subsequently be jurisdictional by rule, a water 

must contribute flow, either directly or through another water to a traditional navigable 

water, interstate water, territorial sea, or impoundment. The Agencies, however, have 

proposed no methods to quantify the contribution of flow from tributaries to downstream 

waters. This causes particular concerns related to how the Agencies will determine if a 

water contributes flow in those instances where a break occurs along the length of a 

tributary. For example, what if flow from the tributary goes subsurface or evaporates 

along the length of the break? If 100% of the flow entering the break infiltrates to a deep 

groundwater aquifer or evaporates along the length of the break, the upstream tributary is 

in fact not contributing flow to a downstream (a)(l) through (4) water and thus would not 

meet the definition of tributary.

Similarly, both water quantity and quality change along stream reaches and tributary 

networks. In fact, the draft Connectivity Report recognizes that "streams and rivers are 

not pipes," and because of this, "water can be lost from the channel through evaporation 

 

194 Leibowitz, S.G. 2003. Isolated wetlands and their functions: an ecological perspective. Wetlands: 23(3):517-531
Clean Water Rule Response to Comments – Topic 8: Tributaries

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and bank storage and diluted through downstream inputs."195 Additionally, the draft 

Connectivity Report states, "if geographically isolated unidirectional wetlands have 

surface water outputs [which would be defined as tributaries if they possess a bed, bank, 

and OHWM and contribute flow to an (a)(l) through (5) water] . . . the probability that 

surface water will infiltrate or be lost through evapotranspiration increases with 

distance."196

Without methods to determine if a water actually contributes flow, the Agencies will 

likely rely on visual assessments alone. Clearly, the presence of a bed, a bank, and an 

OHWM and surface 1 flow in an Arid West ephemeral stream channel could be mistaken 

for a contributing flow when I in fact the water flowing across the landscape does not 

contribute flow to a downstream I traditional navigable water, interstate water, territorial 

sea, or impoundment. As an example, we highlight research that has been conducted by 

the United States Department of Agriculture at the Walnut Gulch Experimental 

Watershed in southeastern Arizona. The Walnut Gulch watershed is characterized by a 

dense network of ephemeral stream channels (Fig. 6).

Figure 6: Ephemeral stream network in Walnut Gulch watershed (near Tucson, 

Arizona).197

The Walnut Gulch watershed is classified as semi-arid, and receives an average of 13.8 

inches of rain per year. When it does rain, both the ground and the air are very “thirsty.” 

As a result, an overwhelming amount of the precipitation is lost to groundwater (i.e., 

infiltration) or the sky (i.e., evaporation). The below figure shows the water balance for 

the Walnut Gulch watershed (Fig. 7).

 

195 Draft Connectivity Report at 3-23 and 3-41.

196 Id. at 3-42.

197 Modified from Walnut Gulch Experimental Watershed Research Brochure. United States Department of

Agriculture, Agricultural Research Service, and Southwest Watershed Research Center (October, 2003), at 17.
Clean Water Rule Response to Comments – Topic 8: Tributaries

208

Figure 7: Walnut Gulch watershed annual water balance.198

The take home from Fig. 7 is that while 13.8 inches of rain falls on the watershed 

annually, less than 0.1 inches travels as streamflow down the network. Of the rain that 

falls on the watershed – a network of hundreds of miles of ephemeral channels with beds, 

banks, and OHWMs – only 0.5% flows to downstream waters! Across the Walnut Gulch 

watershed and, indeed much of the arid Western United States, most stream flows 

traverse dry channels. As water flows over these “thirsty” channels, even more flow 

volume is lost to transmission losses, or infiltration to stream banks and groundwater 

(Fig. 8). The landscape is highly dissected by a dense dry channel network (Fig. 6) 

providing significant opportunity for transmission losses. In a recent report on nonperennial streams in the arid and semi-arid Southwestern United States, EPA and USDA 

scientists note, “Numerous authors have documented substantial transmission losses in 

ephemeral streams, frequently to such an extent that flows infiltrate completely before 

reaching the watershed outlet (Keppel and Renard, 1962; Aldridge, 1970).”199 Without 

describing methods to determine the contribution of flow from these so-called 

“tributaries,” a bed, a bank, an OHWM, and the mere presence of flow might be 

wrongfully interpreted as meeting the proposed definition of tributary. It is critical that

the Agencies describe methods that will be used to distinguish the presence of flow in a 

channel from the contribution of flow from that channel to an (a)(1) through (4) water.

 

198 Source: Id. at 21.

199 Levick, L., J. Fonseca, D. Goodrich, M. Hernandez, D. Semmens, J. Stromberg, R. Leidy, M. Scianni, D. P. 

Guertin, M. Tluczek, and W. Kepner. 2008. The Ecological and Hydrological Significance of Ephemeral and 

Intermittent Streams in the Arid and Semi-arid American Southwest. U.S. Environmental Protection Agency and 

USDA/ARS Southwest Watershed Research Center, EPA/600/R-08/134, ARS/233046, at 33, citing: Keppel, R.V. 

and K.G. Renard. 1962. Transmission losses in ephemeral stream beds. Journal of the Hydraulics Division, ASCE, 

v. 8, n. HY3, p. 59-68; Aldridge, B.N. 1970. Floods of November 1965 to January 1966 in the Gila River Basin, 

Arizona and New Mexico, and adjacent basins in Arizona; US Geological Survey Water-Supply Paper 1850-C, 176
Clean Water Rule Response to Comments – Topic 8: Tributaries

209

Figure 8: An example of transmission losses in Walnut Gulch watershed. The August 27, 1982 storm was isolated in 

the NW portion of the watershed (top panel). The runoff measured at Flume 6 (left peak) amounted to 2.46 x 10m3. 

Runoff then traversed 4.2 km of dry streambed between Flume 6 and Flume 2, resulting in significant infiltration 

losses (middle peak). During the course of the 6.6 km from Flume 2 to Flume 1, the peak discharge was further 

reduced (right peak). The image in the bottom right depicts an advancing flow front down the dry channel.200

Indeed, the importance of quantifying flow is noted in the existing guidance: “For 

purposes of demonstrating a connection to traditional navigable waters, it is appropriate 

and reasonable to assess the flow characteristics of the tributary at the point at which 

water is in fact being contributed to a higher order tributary or to a traditional navigable 

water.”201 The Agencies must propose scientific methods to quantify the contribution of 

flow from a water to an (a)(l) through (4) water. Determining if a water contributes flow 

to a downstream water should not be made based on visual identification alone, precisely 

because "streams and rivers are not pipes." This particularly true in arid regions, as noted 

in the Walnut Gulch example (see Section VI. c. iv. 5.b. i.), and in instances where a 

break (s) exist between the water and the downstream water (see Section VI. c. iv. 4.) (p. 

66-70)

Agency Response: See summary responses for sections 8.1.1 and 8.4. The 

definition of “tributary” in the final rule requires that flow must be of sufficient 

volume, frequency, and duration to create the physical characteristics of bed and 

banks and an ordinary high water mark. The final rule does not require an 

evaluation of flow volume, flow duration and flow frequency for tributaries because 

the agencies have determined that existing science supports the conclusion that all 

waters that meet the definition of “tributary” and that are not excluded in 

 

200 From id. at 18.

201 2008 Rapanos Guidance at 10.
Clean Water Rule Response to Comments – Topic 8: Tributaries

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paragraph (b), have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. By 

grounding the definition of “tributary” to the above referenced specific physical 

features, the agencies believe that confusion regarding whether a feature is a 

“tributary” or a non-jurisdictional “erosional feature” will be minimal. Section VII 

of the Technical Support Document further discusses the science supporting the 

agencies’ conclusion that all waters that meet the definition of “tributary” and that 

are not excluded in paragraph (b), have a significant nexus either individually or in 

the aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. See also summary response under section 8.4: Distinction between ephemeral 

water and a non-jurisdictional gulley, rill or non-wetland swale. See also responses 

addressing significance of “breaks” in bed and bank and OHWM and discussion in 

TSD and elsewhere regarding consistency of rule with applicable Supreme Court 

cases.

8.245 c. The Agencies Fail to Define “Another Water.”

A water satisfies the definition of tributary if it has a bed, bank, and OHWM and 

contributes flow, either directly or through another water, to an (a)(l) through (4) water. 

Again, the Agencies have failed to define a critical term within the tributary definition. In 

this instance, they have not defied "another water." Left undefined, "another water" is left 

open to limitless interpretation. For example, if 100% of the surface water in an 

ephemeral stream with a bed, bank, and OHWM in the Arid West evaporates to water 

vapor, condenses on tiny particles in the air to form a cloud, and then falls from the cloud 

as rain into the Colorado River, it has contributed flow to a traditional navigable water; it 

would meet the tributary definition. Let's say manmade aqueducts and tanker trucks 

collect water from a waterbody and deliver it to a drinking water reservoir during a 

period of drought, those aqueducts and trucks have contributed flow. Would the water 

from which the drinking water was collected meet the tributary definition? As another 

example, a USGS study of the Delmarva Peninsula found that groundwater return times 

(the time required for recharge at the water table to return to a stream through 

groundwater) can take from years to decades.202 If an ephemeral stream on the Delmarva 

Peninsula recharges groundwater and only returns to a downstream tributary some 60 

years later, has it contributed flow and met the tributary definition?

Is "another water" synonymous with the Agencies' overbroad definition of "water" 

provided in footnote 3 of the preamble? In other words, does "another water" include 

"chemical, physical, and biological features" associated with water bodies as traditionally 

understood? If so, if a muskrat associated with a tributary (which would meet the 

overbroad footnote definition of "water") drinks water from that tributary, travels to a 

downstream (a)(l) through (4) water, and urinates therein, the muskrat has functioned as 

"another water" to contribute flow to an (a)(l) through (4) water.

While these hypotheticals may seem farfetched, without defining "another water," the 

contribution of flow necessary to meet the tributary definition can result from any two 

 

202 Sanford, W.E., and J.P Pope. Quantifying Groundwater's Role in Delaying Improvements to Chesapeake Bay

Water Quality. Environ. Sci. Technol. 2013,47,13330-13338.
Clean Water Rule Response to Comments – Topic 8: Tributaries

211

atoms of hydrogen combined with one atom of oxygen that together make their way to 

any downstream (a)(l) through (4) water. This is absurd. "Another water" must be defined 

if the Agencies intend the proposed rule to provide clarity to the "waters of the United 

States" definition. (p. 70)

Agency Response: The definition of “tributary” in the final rule retains the 

phrase “contributes flow, either directly or through another water.” This reflects 

scientific literature about the connectivity among waters discussed in the summary 

response of this section, the Technical Support Document, and the Science Report. 

The final rule does not require that the flow be contributed either directly or 

through waters that are themselves jurisdictional. Water contributed through nonjurisdictional features can have the same impact on the integrity of downstream 

waters as water contributed through jurisdictional waters. See further discussion in 

summary response 8.1.1 above. 

New Mexico Mining Association (Doc. #8644)

8.246 Comment 3: The final rule should not permit jurisdiction under (a)(5) or (a)(6) on 

the basis of surface connections or contributions of flow that are less than perennial.

In two instances, the proposed rule confusingly permits jurisdiction over waters based on 

the vague and undefined concepts of ephemeral and intermittent surface connections. 

First, the proposed rule states that a wetland, lake or pond that contributes even

ephemeral or intermittent flow to a water identified in (a)(l) through (a)(3), is a tributary 

and jurisdictional under (a)(5). See 79 Fed. Reg. 22202 . Second, the proposed rule states 

that a water with an intermittent or ephemeral confined surface connection with a water 

identified in (a)(l) through (a)(5), can be "adjacent" and therefore jurisdictional under 

(a)(6). See 79 Fed. Reg. 22208 .

The rule's use of ephemeral and intermittent connections is both unclear and overexpansive. Could a surface connection or contribution of flow be too intermittent? For 

instance, especially in the arid Southwest, flooding events can lead to "fill and spill" 

contributions of flow through confined surface paths, but only once every 50 or more 

years. In this commenter's view, if such flooding events, despite their infrequency, 

subjected otherwise isolated and distant waters to the agencies' jurisdiction, such an 

expansive approach is well beyond the "significant nexus" standard.

The final rule should be amended such that only perennial flows are sufficient to establish 

jurisdiction. Alternatively, the final rule should more clearly define the frequency of 

surface connection or contribution of flow required to be considered "intermittent" for 

purposes of inclusion as a "tributary" or "adjacent" water. (p. 3)

Agency Response: See summary responses for sections 8.1.1, 8.3 and 8.4. 

Ephemeral streams with sufficient flow to create the physical characteristics of bed 

and banks and an OHWM meet the definition of tributary under the final rule, and 

are thus considered waters of the United States. The agencies concluded that such 

streams provide important functions for downstream waters, and in combination 

with other protected tributaries in a watershed significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas. However, the final rule expressly indicates in paragraph (b) 
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212

that ephemeral reaches that do not meet the definition of tributary are not waters of 

the United States. Section VII of the Technical Support Document discusses the 

science supporting the agencies’ conclusion. See also summary responses in 

Compendium 7 of this RTC, “Features and Waters Not Jurisdictional,” for a broad 

discussion of the final rule’s excluded features.

Reclamation and Abandoned Mine Lands Divisions, Public Service Commission, North Dakota 

(Doc. #12857)

8.247 ... to better explain and illustrate areas to be covered by the proposed rule, we strongly 

recommend that EPA/COE provide specific examples of tributaries (especially ephemeral 

streams) and isolated water bodies in different regions of the country that would be 

categorically considered as jurisdictional waters under the proposed definition and those 

that would not be jurisdictional. More specific examples should also be provided where 

case-by-case jurisdictional determinations will be needed. Providing these examples and 

then re-opening the comment period will provide all interested parties with a better 

understanding of the scope of the "waters of the United States" definition. (p. 2)

Agency Response: See summary responses for Sections 8.1 and 8.4. The final rule 

does not require that a case-by-case determination be made regarding whether an 

ephemeral or tributary stream has a significant nexus to navigable waters; rather, 

waters that meet the definition of tributary (as defined in the rule) that are not 

otherwise excluded under paragraph (b) are categorically considered to be waters of 

the United States are tributaries. Section III(C) of the preamble and Section VII of 

the Technical Support Document discuss the science supporting the agencies’ 

determination that waters meeting the definition of “tributary” have a significant 

nexus because they significantly affect the chemical, physical, and biological 

integrity of traditional navigable waters, interstate waters, and the territorial seas. 

Section I of the Technical Support Document describes the legal basis of the final 

rule, including its consistency with the statute and case law. The agencies will work 

to provide the public technical guidance and examples of final jurisdictional 

determinations during rule implementation. 

Enefit American Oil (Doc. #13438)

8.248 The agencies’ determination that these ephemeral features, many of which may flow for 

only a few hours or days following a rain event, categorically have a significant nexus to 

traditional navigable waters and are therefore jurisdictional is not supported by science 

and therefore cannot be used in any final rule.

Enefit recommends the agencies revisit the definition of a “tributary” and base that 

definition in sound science and legal precedent. Enefit also recommends that the carte 

blanche treatment of tributaries as WoUS be re-evaluated. While Enefit acknowledges 

and appreciates the agencies’ attempt at improving clarity and efficiency in WoUS 

jurisdictional determinations (“JDs”), the proposed rule is a dramatic expansion of 

Federal regulation under the CWA, particular in the arid western U.S. If evaluating the 

significance of a nexus by a tributary to a traditional navigable water is necessary for 

determining jurisdiction under the CWA, then so be it – that work must be done. To 

simply default to a position that the mere presence of a nexus means that it is significant 
Clean Water Rule Response to Comments – Topic 8: Tributaries

213

is unreasonable, arbitrary and capricious, and represents a gross expansion of Federal 

jurisdiction in the arid western U.S. Further, this presumption is in direct conflict with 

Justice Kennedy’s opinion in Rapanos, where the significant nexus test has its genesis. 

(p. 3)

Agency Response: Agency Response: The agencies disagree that tributaries 

cannot be categorically considered waters of the United States. See summary 

response for section 8.1.1. The agencies’ position in regard to tributaries is rooted in 

a science-based conclusion that such waters have a significant nexus either 

individually or in the aggregate with traditional navigable waters, interstate waters, 

and the territorial seas. Section VII of the Technical Support Document discusses 

the science supporting the agencies’ conclusion. Further, Section I of the Technical 

Support Document discusses the legal issues concerning the final rule, including 

consistency with the statute and Supreme Court decisions.

Arizona Mining Association (Doc. #13951)

8.249 4. The “contribute flow” standard in the proposed definition of “tributary” needs to be 

defined with specificity as applied to the ephemeral systems in the arid West: The 

requirement to determine whether a potential water “contributes flow” to a downstream 

water, and is thus a regulated tributary under the proposal, can be complicated in arid 

systems. Small ephemeral washes distant from larger regulated waters may contribute 

water to those larger waters only on a very infrequent basis (e.g., in a 5, 10, 25, 50, 100 or 

even 500 year event). Are all of these washes treated as “contributing flow” to the 

downstream water? Is the mere presence of a traceable physical connection, no matter 

how lengthy or tenuous, sufficient to establish a tributary relationship, and thus create a 

presumption of jurisdiction? That certainly seems to be the intent of the proposal, but as 

noted above, such an approach flatly contradicts the statement in Justice Kennedy’s 

concurring opinion in Rapanos that “mere hydrologic connection should not suffice in all 

cases; the connection may be too remote or insubstantial for the hydrologic linkage to 

establish the required nexus with navigable waters as traditionally understood.” See 547 

U.S. at 784.

Due to infrequent flow, in combination with transmission losses and other factors, even 

dry desert washes located in close proximity to a TNW often will lack any ability (or 

possess very limited ability) to contribute flow to the TNW. Ephemeral washes in the arid 

West tend to be “losing systems,” meaning that much of the water that may flow in 

ephemeral washes in response to infrequent storm events will be lost to infiltration before 

it travels very far. One may be able to trace a line on a map that connects a distant 

headwater ephemeral wash to a downstream TNW, but in reality water from the wash 

may have little or no potential of reaching the downstream water in any realistic scenario. 

The proposed rule’s assumption that ephemeral washes always or routinely contribute 

flow to TNWs is factually flawed. Rather, in most instances, dry desert washes will lack 

any relevant physical connection much less any type of “significant nexus” to a 

downstream TNW. For example, at the Silver Bell Mine in Pima County, Arizona, an 

applicant provided information showing that even in a 100-year, 24-hour storm event, 

water in headwater ephemeral washes would only travel an estimated 12.9 miles from the 

mine. The nearest TNW in that case was over 100 miles away. In a situation such as that, 
Clean Water Rule Response to Comments – Topic 8: Tributaries

214

the headwater wash has no realistic chance of contributing flow to the TNW, and should 

not be considered a tributary that is automatically regulated. (p. 12)

Agency Response: See summary response for sections 8.1.1 and 8.4. The definition 

of “tributary” in the final rule requires that flow must be of sufficient volume, 

frequency, and duration to create the physical characteristics of bed and banks and 

an ordinary high water mark. The Agencies believe that grounding the definition of 

“tributary” in the final rule to the above referenced specific physical features will 

help clarify the distinction between covered tributaries and erosional features, and 

simplify implementation of the final rule. Section VII of the Technical Support 

Document further discusses the science supporting the agencies’ conclusion and its 

consistency with Supreme Court case law.

Nevada Mining Association (Doc. #14930)

8.250 Many Ephemeral and Intermittent Drainages Could Be Deemed "Tributaries": It is highly 

questionable, to say the least, whether ephemeral and intermittent drainages in the arid 

and semi-arid West that flow for at most a few days or weeks every year or every few 

years, and where the flow may reach a TNW or a tributary thereof once every decade, 

have or could have any impact on a TNW located scores of miles away, let alone a 

significant impact. As the WAC comments show, the Agencies lack any sound scientific 

basis for concluding that such drainages could have any such significant adverse impact 

on a TNW. Nonetheless, under the Proposal, it appears that all such ephemeral and 

intermittent drainages would be deemed "tributaries" and therefore per se jurisdictional if 

they physically connect with, and contribute even one drop of surface flow to, a TNW or 

its major tributaries. Thus, the Proposal defines the term "tributary" to mean any "water 

physically characterized by the presence of bed and banks and ordinary high water mark" 

and "which contributes flow, either directly or through another water," to a TNW. See, 

e.g., paragraph (c)(5) at 79 Fed. Reg. 22263. Moreover, a "tributary" as so defined does 

not lose its status as a tributary if, for any length , there are one or more natural breaks 

(such as a stream that flows underground) so long as a bed and bank and an ordinary high 

water mark can be identified upstream of the break. Id.

In certain member companies' meetings with Corps and EPA officials, those officials 

stated that ephemeral and intermittent drainages are jurisdictional under the Proposal, 

regardless of how infrequently flow is actually observed from the drainage to a seasonal 

or perennial stream (even if only once every decade or several decades), so long as the 

drainage has a bed, banks, and ordinary high water mark, and it physically connects 

(without losing its channel definition) to a TNW or tributary to a TNW. EPA and Corps 

officials were adamant that the bed, banks, and ordinary high water mark are physical 

manifestations that the drainage has a high enough volume, frequency, and duration of 

flow that it "contributes flow" to a TNW or tributary system. See also, 79 Fed. Reg. 

22202 (stating these features "generally are physical indicators of flow"). Thus, in the 

Agencies' view, regulators need not demonstrate that an ephemeral or intermittent 

drainage actually "contributes flow" - even one drop of water - to a TNW to be 

considered a jurisdictional "tributary"; rather, so long as the drainage has the physical 

characteristics defined by the Agencies as indicating flow, and the drainage channel 

connects by surface to a TNW or a tributary of a TNW, it is per se jurisdictional. This 
Clean Water Rule Response to Comments – Topic 8: Tributaries

215

approach fails to conform with the morphogenesis of certain features in the Great Basin, 

where some drainages are established during very rare (hundreds of years) extreme 

precipitation events. 

The Agencies' assertion of jurisdiction over all such "tributaries" is a reversal of the 

position taken in the 2008 Guidance, and is directly contrary to Justice Kennedy's 

"significant nexus" test set forth in the Rapanos decision. It is also contrary to the 

Rapanos plurality's concept of a "tributary," which requires that streams flow 

continuously at least seasonally to be considered per se jurisdictional. In NvMA's view, 

the Agencies' position in the 2008 Guidance that only "relatively permanent" tributaries 

are per se jurisdictional is reasonable, while the definition of a tributary in the Proposal is 

not. Drainages that rarely flow, and in particular ephemeral or intermittent drainages that 

flow once every decade or so, cannot rationally be said to affect in all cases, much less to 

significantly affect, the chemical, physical, or biological integrity of a downstream TNW, 

which in the arid/semi-arid West would be many, many miles away. To the extent the 

Agencies are relying on the U.S. EPA Draft Report: "Connectivity of Streams and 

Wetlands to Downstream Waters: A Review and Synthesis of Scientific Evidence," 

Docket No. EPA-HQ-OA-2013-0582 (November 6, 2013) to support the proposed 

definition of "tributary," NvMA notes that, as explained in the WAC comments, the 

science underlying this Report deals mostly with areas of the U.S. where ephemeral and 

intermittent drainages do experience significant flows on an annual basis, not with the 

arid/semi-arid West.

As such, and as we discuss more fully below, we believe that the Agencies must, at a 

minimum, exclude ephemeral and intermittent drainages from the category of per se 

jurisdictional waters and include flow volume and duration requirements when 

determining on a case-by-case basis the jurisdictional status of particular ephemeral and 

intermittent drainages. Absent such changes to the Proposal, there is a significant chance 

that many ephemeral and intermittent drainages on mine properties that no regulator 

would ever heretofore have considered as even potentially jurisdictional (because their 

flow is so small that they could not, under any stretch of the imagination, significantly 

affect a downstream TNW) , might now be regulated as "tributaries." (p. 17-19)

Agency Response: See summary responses for sections 8.1.1 and 8.4. The 

agencies' position in regard to tributaries is rooted in a science-based conclusion 

that such waters have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Section I of 

the Technical Support Document further discusses the legal issues concerning the 

final rule, including consistency with the statute and Supreme Court decisions. 

Section VII of the Technical Support Document discusses the science supporting the 

agencies' conclusion.

Barrick Gold of North America (Doc. #16914)

8.251 ...a channel could be declared a tributary without any documentation that flow from the 

channel actually reached the jurisdictional water. And even if flow were documented, the 

significance of it is beside the point. By using aggregation, the agencies have made the 

significance of contribution by the individual channel irrelevant.
Clean Water Rule Response to Comments – Topic 8: Tributaries

216

The unnamed channel at Barrick’s Goldstrike/Arturo facility is not atypical. There are

ephemeral drainages like this all over the West. They may conduct flow once or twice a 

year during precipitation or snowmelt, or may do so much less frequently. As likely as 

not, their bed, banks and ordinary high water marks are evidence of extraordinary 

flooding that happened in the distant past. In all but the most unusual circumstances, 

these kinds of drainages would have zero impact on remotely located traditional 

navigable waters. The agencies cannot justify a rule that imposes jurisdiction on all such 

drainages per se.

...the agencies could address many of Barrick’s concerns with the proposed rule by 

taking the following actions:

...

 Clarify that in order to be considered a tributary, the agencies must establish that 

the channel in question actually contributes flow to a traditional navigable water, 

interstate water, or territorial sea, and that the flow is of a quantity and frequency 

that constitutes a “significant nexus.”

... (p. 18, 29)

Agency Response: See summary response for sections 8.1.1 and 8.4. The final rule 

does not require an evaluation of flow volume, flow duration and flow frequency for 

tributaries because the agencies have concluded that all waters that meet the 

definition of "tributary" and that are not excluded in paragraph (b), have a 

significant nexus either individually or in the aggregate with traditional navigable 

waters, interstate waters, and the territorial seas. Section VII of the Technical 

Support Document discusses the science that supports this conclusion in detail.

Virginia Coal and Energy Alliance and Virginia Mining Issues Group (Doc. #18016)

8.252 II. Extending Jurisdiction to Ephemeral Streams is an Impermissible Expansion of 

Federal Jurisdiction

Under the Proposal, all tributaries - perennial, intermittent and ephemeral - are deemed to 

be per se jurisdictional. But this is a flawed position that deviates from binding Supreme 

Court precedent established in Rapanos v. United States, 547 U.S. 715 (2006) and that 

rests on the unsupported scientific and legal assumption that all tributaries are important 

to the chemical, physical and biological integrity of traditional navigable waters, 

interstate waters and the territorial seas. See Proposed Rule at 22201. Historically, only 

ephemeral streams with an ordinary high water mark ("OHWM") have been deemed 

jurisdictional. See 65 Fed. Reg. 12823(2000) and GAO-04-297 Report "Waters and 

Wetlands: Corps of Engineers Needs to Evaluate Its District Office Practices in 

Determining Jurisdiction; see also EPA and USACE, Questions and Answers for 

Rapanos and Carabell Decision, June 5, 2007, at pg. 11 (" ... some ephemeral tributaries 

and their adjacent wetlands will not be jurisdictional under the CWA.") (emphasis 

added).203 Yet now, without justification, the Agencies are seeking to abandon this past 

 

203 Available at http://www.usace.anny.mil/Portals/2/docs /civilworks/regulatory/cwa_guide/rapanos ga 06-0507.

pdf.
Clean Water Rule Response to Comments – Topic 8: Tributaries

217

practice and instead assert blanket jurisdiction over all tributaries, including ephemeral 

streams.

As a threshold matter of statutory construction, the fact that Congress explicitly sought to 

limit federal jurisdiction under the CWA to only certain "navigable" "waters of the 

United States" underscores the fact that certain other waters necessarily fall beyond its 

reach. See 33U.S.C. §§ 1311(a), 1342(a) and 1362(7). Claiming per se jurisdiction over 

ephemeral streams would essentially render the word "navigable" meaningless. Surely 

Congress did not intend for this critical term to be read out of the Act by agency 

regulation.

At the same time, this move to automatically capture ephemeral streams as jurisdictional 

would directly contravene the "significant nexus" test that Justice Kennedy set forth in 

Rapanos ("This standard presumably provides a rough measure of the volume and 

regularity of flow. Assuming it is subject to reasonably consistent application ... it may 

well provide a reasonable measure of whether specific minor tributaries bear a sufficient 

nexus with other regulated waters to constitute ' navigable waters' under the Act.") 

(quoting J. Kennedy) (Rapanos at 781-782). Justice Kennedy's significant nexus test does 

not support a broad and unlimited assertion of jurisdiction over all tributaries without 

regard to their connection to downstream waters.

Ephemeral streams and drainages are a common feature across the SVC landscape. Most 

of these ephemeral streams are long distances from traditionally navigable waters 

("TNWs") and have not been determined to be jurisdictional in the past. Under the 

Proposal, they would now become jurisdictional.

...

In sum, what the Agencies have proposed with respect to ephemeral streams is both 

legally deficient and unworkable in practice, particularly for Virginia's coal mining 

industry. (p. 4-5)

Agency Response: See summary responses for sections 8.1.1 and 8.4. Compared 

to the historic scope of the existing rule, the final rule is narrower; compared to 

agency practice in light of guidance issued after SWANCC and Rapanos, the final 

rule is generally broader, but not broader than the existing rule. Section I of the 

Technical Support Document further discusses the legal issues concerning the final 

rule, including consistency with the statute and Supreme Court decisions. Section 

VII of the Technical Support Document discusses the science supporting the 

agencies’ conclusion.

Montana Wool Growers Association (Doc. #5843.1)

8.253 Section (a)(5) allows the Agencies to regulate land. Section (c)(5) defines "tributary" as a 

"water physically characterized by the presence of a bed and banks." A "water" cannot be 

"characterized by . . . a bed and banks." The language instead implies the channel (the 

land feature) and not water within the channel is the WOTUS. If the Agencies intend to 

regulate water rather than land features, the Proposed Rule should not treat the two the 

same. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

218

a. The Proposed Rule should clarify that only waters are jurisdictional, not land features 

(e.g. "tributary means water within a channel that is physically characterized by the 

presence of a bed and banks"). (p. 7)

Agency Response: See summary responses for sections 8.1.1 and 8.4. The 

Agencies believe that the physical characteristics of bed and banks and ordinary 

high water mark indicate there is sufficient volume, duration and frequency of flow

in a water to have a significant effect on the chemical, physical, and biological 

integrity of traditional navigable waters, interstate waters, and the territorial seas. 

Section VII of the Technical Support Document discusses the science supporting the 

agencies’ conclusion.

8.254 3. Section (a)(5) is unclear. The Proposed Rule identifies a tributary "by the presence of a 

bed and banks and ordinary high water mark" and whether it "contributes flow, either 

directly or through another water, to [an (a)(l) through (a)(4) water]." In the arid west, 

both erosional features and ephemeral streams have all three characteristics and 

contribute flow to downstream waters. Further, many ephemeral waterways, like 

erosional features, only contribute flow to WOTUS during spring run-off and become 

deeply incised where reservoirs and channel straightening have disrupted natural water 

level and speed. Consequently, many erosional features in the arid west perform the same 

functions as, and are at times indistinguishable from, ephemeral waterways. 

a. The Proposed Rule should not grant the Agencies’ jurisdiction over ephemeral waters. 

(p. 8)

Agency Response: See summary response for sections 8.1.1 and 8.4. The 

definition of “tributary” in the final rule requires that flow must be of sufficient 

volume, frequency, and duration to create the physical characteristics of bed and 

banks and an ordinary high water mark. The Agencies believe that grounding the 

definition of “tributary” in the final rule to the above referenced specific physical 

features will help clarify the distinction between covered tributaries and erosional 

features, and simplify implementation of the final rule. Section VII of the Technical 

Support Document further discusses the science supporting the agencies’ 

conclusion.

Alameda County Cattlewomen (Doc. #8674)

8.255 Not All Waters Under the Definition of Tributary Will Satisfy the Significant Nexus 

Analysis

The agencies cannot categorically make anything with a bed, bank and OHWM that takes 

water somewhere downstream jurisdictional. The proposed rule is clear that the definition 

of 'tributary' does in fact include all ephemeral, intermittent and perennial features and 

that rate of flow (or any flow) is simply not a factor. (Proposed Rule at 22206; (" ...the 

agencies conclude that tributaries, including headwaters, intermittent, and ephemeral 

streams, and especially when all tributaries in a watershed are considered in combination, 

have a significant nexus to traditional navigable waters, interstate waters, or territorial 

seas ...")). ACCW assert that the definition of tributary is overly broad because the 

agencies cannot make all tributaries per se jurisdictional without satisfying the significant 

nexus analysis. (p. 8)
Clean Water Rule Response to Comments – Topic 8: Tributaries

219

Agency Response: The agencies disagree that tributaries cannot be categorically 

considered waters of the United States. See summary response for section 8.1.1. The 

agencies’ position in regard to tributaries is rooted in a science-based conclusion 

that such waters have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

conclusion. Further, Section I of the Technical Support Document discusses the 

legal issues concerning the final rule, including consistency with the statute and 

Supreme Court decisions.

8.256 The proposed rule states “...ditches not excluded in section (b) that, either directly or 

through other tributaries, convey water to...” Yet, this is in conflict with the actual 

definition for a tributary that states “...which contributes flow, either directly or through 

another water,...” It is unclear whether to be a tributary the feature must contribute water 

through any means (i.e. “another water”) or through another tributary. Contributing flow 

through any type of water is clearly expansive, essentially making anything with a bed, 

bank and OHWM a “tributary” and subject to the CWA. It also contradicts the agencies’ 

statements and proposition that the proposed definition does not regulate groundwater, if 

groundwater can serve as the connection, and part of, a “tributary.” ACCW assert that 

neither Congress nor the Commerce Clause of Article I of the U.S. Constitution intended 

or allows such a result.204 The agencies’ definition of “tributary” violates the CWA and is 

beyond the authority of Congress to grant such unlimited authority based on the 

restrictions under the Commerce Clause of the U.S. Constitution. (p. 11)

Agency Response: See summary responses for sections 8.1.1 and 8.4. The final 

rule does not require that the flow be contributed either directly or through waters 

that are themselves jurisdictional. Waters contributed through non-jurisdictional 

features can have the same impact on the integrity of downstream waters as water 

contributed through jurisdictional waters. Section I of the Technical Support 

Document discusses the legal issues concerning the final rule, including consistency 

with the statute and Supreme Court decisions. Section VII of the Technical Support 

Document discusses the science supporting the agencies’ conclusion that all waters 

that meet the definition of “tributary” and that are not excluded in paragraph (b), 

have a significant nexus either individually or in the aggregate with traditional 

navigable waters, interstate waters, and the territorial seas. Paragraph (b) of the 

final rule outlines numerous exclusions for features that will not be waters of the 

United States, including most ditches that are not relocated tributaries or excavated 

in tributaries, groundwater and erosional features, such as gullies and rills.

Maryland Farm Bureau (Doc. #10755)

8.257 The proposed rule provides no basis for distinguishing between erosional features and 

small ephemeral feature. (p. 2)

 

204 SWANCC at 173; (“...we have reaffirmed the proposition that the grant of authority to Congress under the

Commerce Clause, though broad, is not unlimited...But this [Migratory Bird Rule] is a far cry, indeed, from the

‘navigable waters’ and ‘waters of the United States’ to which the statute by its terms extends.”).
Clean Water Rule Response to Comments – Topic 8: Tributaries

220

Agency Response: See summary responses for sections 8.1.1 and 8.4. Paragraph 

(b) of the final rule outlines numerous exclusions for features that will not be waters 

of the United States, including most ditches that are not relocated tributaries or 

excavated in tributaries, groundwater and erosional features, such as gullies and 

rills.

Hancock County, Indiana (Doc. #11980)

8.258 We are concerned that the new definition of a tributary may be used to justify the 

regulation of features which are not considered a "tributary" in any common sense of the 

word. We understand that the features must have a bed, bank and ordinary high water 

mark. Based upon recent apparent implementation of this definition in Indiana, it appears 

that features which are completely ephemeral and drain few acres are going to be 

considered tributaries. Those features provide no base flow and thus would not normally 

be considered a tributary as it is commonly understood or as it would appear to have been 

historically interpreted by the agencies. (p. 2)

Agency Response: See summary responses for sections 8.1.1 and 8.4. Ephemeral 

streams with sufficient flow to create the physical characteristics of bed and banks 

and an OHWM meet the definition of tributary under the final rule, and are thus 

considered waters of the United States. The agencies concluded that such streams 

provide important functions for downstream waters, and in combination with other 

protected tributaries in a watershed significantly affect the chemical, physical, and 

biological integrity of traditional navigable waters, interstate waters, and the 

territorial seas. However, the final rule expressly indicates in paragraph (b) that 

ephemeral reaches that do not meet the definition of tributary are not waters of the 

United States. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion.

Montana Farm Bureau Federation (Doc. #12715)

8.259 Under the proposed rule, the definition of "tributary" is extremely broad and is one of the 

most expansive and problematic terms in the entire rule. The online Oxford Dictionary 

defines "tributary" as "a stream or river that flows into a larger river or lake" and gives 

the example of "The Illinois River is a tributary of the Mississippi River." Therefore, we 

do not believe it is fitting to include tiny, ephemeral streams into the definition of 

"tributary." Ephemeral streams are not really streams at all, since they are dry ground 

most of the time. This aspect is especially problematic in states like Montana because as 

aforementioned, much of the land here is semi-arid and dry most of the year. 

Furthermore, Montana receives a great deal of moisture in the form of snow. Therefore, 

when it warms up in the spring, little streams form to drain the snowmelt into creeks and 

rivers. Those little ephemeral streams may even be defined enough to have a noticeable 

bed, bank and ordinary high water mark. They most likely only run water for a matter of 

days, or even hours at a time. Likewise, summer time in Montana is known to bring about 

thunderstorms which can release several inches of rain within minutes, causing small 

ephemeral streams to pop up for hours or even minutes. The rest of the year, this land is 

dry, grass covered and just a normal part of the pasture or field. It seems absolutely 

unnecessary and far beyond the scope of the Clean Water Act for such land features that 
Clean Water Rule Response to Comments – Topic 8: Tributaries

221

have water running over or standing on them for short periods of time, to be considered a 

"Water of the United States" since they are indeed, usually dry land.

As one may also expect in a semi-arid climate, there many creeks in Montana that only 

run when the snow is melting, or when it rains a significant amount. They may hold some 

stagnant water during wetter times of the year or if there is a natural spring depositing 

water into their banks, or the bed may be completely dry. Even though they are named 

creeks and are commonly called creeks by the farmers and ranchers, they often times 

drain into other creeks, which eventually lead to rivers miles and miles away and should 

really be considered ephemeral streams. The bed may be only a foot or two wide so there 

is absolutely no way these could ever be called navigable, even if there was water 

running in them at the time. 

So called "streams" like the ones mentioned above should never be considered a "Water 

of the United States." Yet, the Agencies insist that "[t]ributaries that are small, flow 

infrequently, or are of substantial distance from the nearest (a)(l) through (a)(4) water, 

e.g., headwater perennial, intermittent, and ephemeral tributaries" are nevertheless part of 

the tributary network regulated by this proposal. 79 Fed. Reg. at 22,206. It is troubling 

that this rule includes numerous definitions for "tributary" and all of them are much too 

broad. For example, at 79 Fed. Reg. 22, 263 the Agencies state that tributaries are "a 

water physically characterized by a bed and banks, and ordinary high water mark ...which 

contributes flow, either directly or through another water to another water" that 

eventually reaches a traditional navigable water. They go on to state that tributaries can 

be natural, man-altered, or man-made. (p. 1-2)

Agency Response: See summary responses for sections 8.1.1 and 8.4. Ephemeral 

streams with sufficient flow to create the physical characteristics of bed and banks 

and an OHWM meet the definition of tributary under the final rule, and are thus 

considered waters of the United States. The agencies concluded that such streams 

provide important functions for downstream waters, and in combination with other 

protected tributaries in a watershed significantly affect the chemical, physical, and 

biological integrity of traditional navigable waters, interstate waters, and the 

territorial seas. However, the final rule expressly indicates in paragraph (b) that 

ephemeral reaches that do not meet the definition of tributary are not waters of the 

United States. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion.

Louisiana Cotton and Grain Association (Doc. #12752)

8.260 Tributaries are jurisdictional by rule, and include all features with a bed, bank and 

ordinary high water mark ("OHWM") that contribute flow, directly or "through another 

water," to a traditional navigable water ("TNW"), interstate water, territorial sea or 

impoundment, including ephemeral, intermittent or perennial flow? Does the undefined 

phrase "through another water" include nonjurisdictional drainages that "contribute flow" 

to a water of the U.S.? How much "flow" is required? How will the volume and duration 

of contributed flow be determined? (p. 2)

Agency Response: See summary responses for sections 8.1.1 and 8.3. The final 

rule does not require that the flow be contributed either directly or through waters 
Clean Water Rule Response to Comments – Topic 8: Tributaries

222

that are themselves jurisdictional. Waters contributed through non-jurisdictional 

features can have the same impact on the integrity of downstream waters as water 

contributed through jurisdictional waters. The agencies maintain that some waters 

may pass through non-jurisdictional waters, such as excluded ditches, but will still 

be classified as tributaries both upstream and downstream of the non-jurisdictional 

feature. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion.

Nebraska Cattlemen (Doc. #13018)

8.261 EPA should withdraw the proposed rule and re-propose the rule with definition of 

tributary and adjacent that is in line with the CWA and Supreme Court case law. 

Nebraska Cattlemen comment that these definitions should be narrowed to require that 

there is water flow present in a tributary at least a majority of the time to trigger 

jurisdiction. Or, provide some test that allows for the field personnel to exclude 

tributaries that only rarely contribute to the water quality of the identified traditionally 

navigable water. Nebraska can provide many examples of tributaries that, even at their 

glory, do not contribute to water quality impacts of any navigable water. (p. 11)

Agency Response: Previous definitions of "waters of the United States" regulated 

all tributaries without qualification. Compared to the historic scope of the existing 

rule, the final rule is narrower; compared to agency practice in light of guidance 

issued after SWANCC and Rapanos, the final rule is generally broader, but not 

broader than the existing rule. See summary response for section 8.1.1. Section I of 

the Technical Support Document further discusses the legal issues concerning the 

final rule, including consistency with the statute and Supreme Court decisions. 

Missouri Agribusiness Association (Doc. #13025)

8.262 Relatively permanent waters (RPW) needs to be defined in the new proposed rule. The 

plurality opinion in Rapanos stated that RPWs “do not necessarily exclude streams, 

rivers, or lakes that might dry up in extraordinary circumstances, such as drought, and 

seasonal rivers, which contain continuous flow during some months of the year but no 

flow during dry months.” This legal description needs technical definition. For clarity and 

ease of use, the new proposed rule should consider utilizing the 1:100K NHD, as was 

done by the State of Missouri. And in Missouri, UAAs are used to delete, and to add, 

waters as needed providing flexibility for the State to adjust to local conditions. (p. 11)

Agency Response: See summary responses for sections 8.1.1 and 8.1.2. The final 

rule eliminates the need to identify a water as relatively-permanent, or conduct a 

significant nexus determination for each tributary. Instead, the final rule establishes 

categorical jurisdiction over all waters that meet the definition of "tributary" and 

that are not excluded in paragraph (b). Section I of the Technical Support 

Document further discusses the legal issues concerning the final rule, including 

consistency with the statute and Supreme Court decisions. Section VII of the 

Technical Support Document discusses the science supporting the agencies' 

determination that waters meeting the definition of "tributary" have a significant 

nexus because they significantly affect the chemical, physical, and biological 

integrity of traditional navigable waters, interstate waters, and the territorial seas.
Clean Water Rule Response to Comments – Topic 8: Tributaries

223

Iowa Corn Growers Association (Doc. #13269)

8.263 ICGA believes that this expansion over intermittent and ephemeral tributaries is 

unlawful. EPA has historically implemented the CWA in Iowa by treating ephemeral 

waters as non-jurisdictional, but the proposed rule strays from that longstanding 

philosophy to include features that are predominantly dry. In addition, the definition 

contains no reference to the volume or frequency of flow, creating uncertainty as to 

whether waters that lack consistent flow would be included, deviating from the plurality 

opinion set forth in Rapanos. (p. 3)

Agency Response: The agencies respectfully disagree with the commenter's 

position that asserting jurisdiction over intermittent and ephemeral streams is 

unlawful. Previous definitions of "waters of the United States" regulated all 

tributaries without qualification. Compared to the historic scope of the existing rule, 

the final rule is narrower; compared to agency practice in light of guidance issued 

after SWANCC and Rapanos, the final rule is generally broader, but not broader 

than the existing rule. See summary response for section 8.1.1. Section I of the 

Technical Support Document further discusses the legal issues concerning the final 

rule, including consistency with the statute and Supreme Court decisions. 

Western Growers Association (Doc. #14130)

8.264 Western Growers asks that the Corps and EPA clarify several aspects of “tributaries”... 

...the proposed regulation makes it clear that to identify a tributary one must determine 

‘flow’ from the waterbody in question into a traditional jurisdictional water.205 Moreover 

the agencies assert in premable—but not in the regulation itself—that tributaries can 

include perennial, intermittent, or ephemeral streams and other waterways.206 Western 

Growers would ask the agencies to clarify with precision the following, before any rule is 

finalized:

1. The proposed definition does not define what amount of flow needs to be 

contributed to create a connection. In commenting on Riverside Bayview Homes as it 

applies to the Corps standards in place at the time, Justice Kennedy in Rapanos noted that 

the agencies in writing their regulations should discuss concepts of flow in terms of 

regularity and volume. Further, in Rapanos Kennedy indicated the Corps standards in 

place at the time were not specific enough to those concepts to pass jurisdictional 

muster—despite many pages of explanation the agencies again appear to ignore this 

requirement.

2. Ephemeral and intermittent streams are discussed in the preamble but are not 

part of the definition of tributary. The agencies must define the relevant hydrological 

features of ephemeral or intermittent streams that will trigger jurisdiction; e.g. what 

amount of “flow” needs to be present? While Justice Kennedy in Rapanos discusses the 

possibility that at least some intermittent and ephemeral waterways would be covered by 

 

205 U.S. Army Corps of Engineers & U.S. EPA, Definition of “Waters of the United States” Under the Clean Water 

Act; Proposed Rule, 79 Fed. Reg. 22,188, 22,201 (April 21, 2014). Proposed “Definition of ‘Waters of the United 

States’ Under the Clean Water Act” 40 CFR 230.3(c)5

206 Id. at 22,202.
Clean Water Rule Response to Comments – Topic 8: Tributaries

224

the Act that does not abrogate the agencies responsibility to delineate which types of 

intermittent or ephemeral waterways would qualify jurisdictionally and which would not, 

based on some description of hydrological conditions.

Clarification surrounding ephemeral or intermittent streams is absolutely critical in the 

arid West where these features are common place. While regulated entities may not fully 

have all the technical capabilities at their disposal that the Corps or EPA have, without 

more precise definition members of the regulated community are left with no way to even 

approximate which waters fall under the Act’s jurisdiction pursuant to the definition of 

tributary. Given the uncertainty in the proposed rule we ask EPA and the Corps to answer 

these questions and open a comment period on these clarifications. The rule cannot be 

finalized without further clarification. (p. 12-13)

Agency Response: See summary responses for sections 8.1.1 and 8.4. The 

definition of “tributary” in the final rule requires that flow must be of sufficient 

volume, frequency, and duration to create the physical characteristics of bed and 

banks and an ordinary high water mark. The final rule does not require an 

evaluation of flow volume, flow duration and flow frequency for tributaries because 

the agencies have determined that existing science supports the conclusion that all 

waters that meet the definition of “tributary” and that are not excluded in 

paragraph (b), have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Section VII 

of the Technical Support Document discusses this conclusion in detail. Section I of 

the Technical Support Document further discusses the legal issues concerning the 

final rule, including consistency with the statute and Supreme Court decisions.

Sugar Cane Growers Cooperative of Florida (Doc. #14283)

8.265 Under the proposed rule, tributaries, impoundments of tributaries and waters adjacent to 

tributaries would all become per se jurisdictional. 79 Fed. Reg. at 22,262-63. This would 

prove overly expansive because a “tributary” would include any “water physically 

characterized by the presence of a bed and banks and an ordinary high water mark . . . 

which contributes flow, either directly or indirectly through another water.” Id. at 22,263. 

Wetlands, lakes and ponds would be tributaries regardless of whether they contribute 

flow, have beds and banks or a high water mark. Id. Waters would not lose their status as 

tributaries even if man-made breaks like pipes and culverts exist regardless of the length 

or distance of these man-made breaks. Id. And a tributary would include “natural, manaltered, or man-made water and includes water such as rivers, streams, lakes, ponds, 

impoundments, canals, and ditches [that are not otherwise excluded].” Id. Ditches would 

be excluded from the definition of “tributary” in two limited circumstances: (1) where 

they are excavated wholly in uplands, draining only uplands and having less than 

perennial flow, and (2) where they do not contribute flow, directly or indirectly, to 

jurisdictional waters. Id. at 22,203.

But to comply with the U.S. Supreme Court’s prior decisions, any definition of tributaries 

should focus on issues such as duration and flow so that ephemeral waters and waters 

“remote from any navigable-in-fact water and carrying only minor water-volumes toward 

it” are not subsumed within the definition. Rapanos, 547 U.S. at 781; see also id. at 734. 

The proposed rule includes no such consideration. (p. 7)
Clean Water Rule Response to Comments – Topic 8: Tributaries

225

Agency Response: See summary responses for sections 8.1.1, 8.2 and 8.4. The 

definition of “tributary” in the final rule requires that flow must be of sufficient 

volume, frequency, and duration to create the physical characteristics of bed and 

banks and an ordinary high water mark. As a result, wetlands, lakes, ponds, and 

other features lacking a bed and banks and/or OHWM are no longer defined as 

tributaries. However, they still may be considered jurisdictional waters of the U.S. 

either as adjacent waters. The final rule does not require an evaluation of flow 

volume, flow duration and flow frequency for tributaries, which was referenced in 

the 2008 Guidance, because the agencies have determined that existing science 

supports the conclusion that all waters that meet the definition of “tributary” and 

that are not excluded in paragraph (b), have a significant nexus either individually 

or in the aggregate with traditional navigable waters, interstate waters, and the 

territorial seas. Paragraph (b) of the final rule outlines numerous exclusions for 

features that will not be waters of the United States, including most ditches that are 

not relocated tributaries or excavated in tributaries, as well as artificial lakes and 

ponds created in dry land and used primarily for stock watering, irrigation, settling 

basins, etc. In addition, all existing statutory exemptions, including those at CWA 

section 404(f) for normal farming, silviculture and ranching activities and for 

maintenance of existing irrigation and drainage ditches remain in effect and 

unchanged by the final rule. Section I of the Technical Support Document further 

discusses the legal issues concerning the final rule, including consistency with the 

statute and Supreme Court decisions.

Wyoming Farm Bureau Federation (Doc. #14406)

8.266 Intermittent and ephemeral streams should not be considered as tributaries to WOTUS. 

The description used by the EPA and the Corps for tributary is contrary to all 

understanding. Using “beds and banks, bottom and lateral boundaries, or other 

indicators” is so broad that any kind of land feature could qualify as WOTUS. Again, 

clarity and increased understanding is not occurring. Allowing EPA or Corps personnel 

to make these decisions will again be something that will be nearly impossible to prove 

or disprove. Once designated WOTUS, landowners will be heavily burdened to dedesignate. Clarity and certainty is not being given to landowners but additional costs of 

time and money are. (p. 3)

Agency Response: See summary responses for sections 8.1.1, 8.2 and 8.4. The 

agencies have determined that existing science supports the conclusion that all 

waters that meet the definition of “tributary” and that are not excluded in 

paragraph (b), have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Paragraph 

(b) of the final rule outlines numerous exclusions for features that will not be waters 

of the United States, including most ditches that are not relocated tributaries or 

excavated in tributaries, as well as artificial lakes and ponds created in dry land and 

used primarily for stock watering, irrigation, settling basins, etc. In addition, all 

existing statutory exemptions, including those at CWA section 404(f) for normal 

farming, silviculture and ranching activities and for maintenance of existing 

irrigation and drainage ditches remain in effect and unchanged by the final rule
Clean Water Rule Response to Comments – Topic 8: Tributaries

226

Kansas Farm Bureau (Doc. #14408)

8.267 The proposed definition of a tributary is simply another attempt by EPA and the Corps to 

greatly overreach the jurisdiction bestowed on them in the Clean Water Act. As was 

stated earlier, even Justice Kennedy (the Justice whose opinion the agencies are relying 

on) stated that the Corps’ treatment of any channel that “feeds into a traditional navigable 

water (or a tributary thereof) and possesses an ordinary high-water mark defined as a 

“line on the shore established by the fluctuations of water and indicated by [certain] 

physical characteristics” as a “tributary” subject to regulation under the CWA is overly 

broad. Kennedy opined that it “seems to leave wide room for regulation of drains, 

ditches, and streams remote from any navigable-in-fact water and carrying only minor 

water-volumes towards it.” 207 The proposed rule simply attempts to reword the definition 

of a tributary that Justice Kennedy and the plurality has already rejected. Once again, this 

action does not provide clarity; it simply is another attempt by the agencies to expand 

their jurisdiction beyond the reasonable bounds of the statute.

By defining tributaries in this manner, the agencies are attempting to include intermittent 

and ephemeral streams as jurisdictional waters.

208 The effect of this action is that the 

Corps and EPA are attempting to include a significant amount of land that rarely has 

water on it as a jurisdictional water. Once again, this is an extreme overreach on the part 

of the federal government.

Given the broad proposed definitions of tributaries and other waters, KFB requests that 

the agencies provide a detailed description of the anticipated interplay between these 

definitions and the exemption provided in the CWA for nonpoint source pollution. KFB 

joins with the comments and concerns of the American Farm Bureau Federation relating 

to the proposed definitional changes and impacts on nonpoint source pollution. (p. 7-8)

Agency Response: See summary responses for sections 8.1.1, 8.2 and 8.4. The final 

rule categorically considers tributaries, as defined in the rule that are not otherwise 

excluded under paragraph (b) to be waters of the United States. Paragraph (b) of 

the final rule excludes many features, including most ditches that are not relocated 

tributaries or excavated in tributaries. See summary responses in Compendium 7 of 

this RTC, “Features and Waters Not Jurisdictional,” for a broad discussion of the 

final rule’s exclusions. Section I of the Technical Support Document describes the 

legal basis of the final rule, including its consistency with the statute and case law.

Section VII of the Technical Support Document discuss the science supporting the 

agencies’ determination that waters meeting the definition of “tributary” have a 

significant nexus because they significantly affect the chemical, physical, and 

biological integrity of traditional navigable waters, interstate waters, and the 

territorial seas. Section I of the Technical Support Document further discusses the 

legal issues concerning the final rule, including consistency with the statute and 

Supreme Court decisions.

 

207 Rapanos at 781.

208 79 Fed. Reg. at 22202.
Clean Water Rule Response to Comments – Topic 8: Tributaries

227

Kansas Agriculture Alliance (Doc. #14424)

8.268 Tributaries Cannot be Categorically Included in WOTUS

The first jurisdictional overreach in the proposed rule can be found in its categorical 

inclusion of all tributaries. The proposed rule states that the term waters of the U.S. shall 

include: “All tributaries of waters identified in paragraphs (a)(1) through (4) . . . .”209 It 

then goes on to define tributaries in (c)(5) as, “a water physically characterized by the 

presence of a bed and banks and ordinary high water mark . . . which contributes flow, 

either directly or through another water”210 to TNW. This definition is so broad it sweeps 

any land feature meeting the above described physical features that might now or in the 

future be wet.

While the Supreme Court has stated that the word navigable is of limited import, it has 

also stated the word “navigable” cannot be completely read out of the CWA.211 The 

Rapanos opinion is particularly insightful in analyzing the agencies’ proposal in relation 

to tributaries. The plurality in Rapanos articulated a clear and decisive limit to the 

inclusion of tributaries as waters of the U.S. It stated, “[T]he phrase ‘waters of the United 

States’ includes only those relatively permanent, standing or continuously flowing bodies 

of water ‘forming geographic features’ that are described in ordinary parlance as 

‘streams[,] . . . oceans, rivers, [and] lakes.’”212 This definition provides a clear limit to 

jurisdiction as it relates to tributaries, which would have provided some level of certainty 

to the agriculture industry that the agencies claim, but fail, to provide with the proposed 

WOTUS rule.

Even if the agencies decide not to follow the pluralities’ definition in Rapanos, however, 

EPA and the Corps are constrained from adopting the current WOTUS definition in the 

proposed rule by the concurring opinion of Justice Kennedy. While Kennedy stated that 

the “Corps may choose to identify categories of tributaries,” he also stated that the 

categorical inclusion cannot ignore volume of flow and proximity to navigable waters.213

Furthermore, Kennedy found that the Corps’ current definition of tributaries provided no 

assurance that flow and proximity to navigable waters was considered.214 He went on to 

criticize the Corps’ current definition of tributary by remarking that “[t]he breadth of this 

standard – which seems to leave wide room for regulation of drains, ditches, and streams 

remote from any navigable-in-fact water and carrying only minor waters toward it –

precludes its adoption as the determinative measure . . . .”215

The definition of tributaries found in the proposed rule, and its inclusion by the agencies 

in the definition of WOTUS, render the term navigable completely meaningless and far 

exceed even the outer bounds of jurisdiction articulated by Kennedy. The above 

definition not only allows the agencies to regulate land that is dry most of the time, but 

 

209 79 Fed. Reg. at 22262.

210 79 Fed. Reg. at 22263.

211 See SWANCC at 172; Rapanos at 731, 779.

212 Rapanos at 739.

213 Id. at 781

214 See id.

215 Id.
Clean Water Rule Response to Comments – Topic 8: Tributaries

228

contains no means of identifying an individual tributaries’ relevance to a TNW. Any 

amount of flow, even a trickle, would deem a land formation a tributary, even if the flow 

is not direct into a TNW.216 This overreach is compounded by the completely undefined, 

and reoccurring term “another water”. This term is not tied to the TNW definition and 

could encompass isolated waters, which the Supreme Court rejected as a basis for 

jurisdiction.217 (p. 3-4)

Agency Response: The agencies disagree that tributaries cannot be categorically 

considered waters of the United States. See summary response for section 8.1.1. The 

agencies’ position in regard to tributaries is rooted in a science-based conclusion 

that such waters have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

conclusion. Further, Section I of the Technical Support Document discusses the 

legal issues concerning the final rule, including consistency with the statute and 

Supreme Court decisions.

Oklahoma Pork Council (Doc. #14911)

8.269 In their WOTUS proposal, EPA and the Corps have defined for the first time what they 

consider to be a tributary. Making all ephemeral and intermittent tributaries jurisdictional

is simply extraordinary. In practice, relying on the plain English meanings of the 

proposed rule, literally millions of drainage features in every part of every farming region 

of the country will have characteristics – a bed, bank and ordinary high water mark – that 

would make them tributaries. This will expand the jurisdiction of EPA and the Corps in 

an unprecedented manner that conflicts with both the clear direction and intent of the 

Supreme Court’s prior numerous decisions that sought to limit the federal jurisdiction 

over private lands. (p. 2)

Agency Response: See summary response for Section 8.1.1. The final rule 

categorically considers tributaries, as defined in the rule and that are not otherwise 

excluded under paragraph (b) to be waters of the United States. Section VII of the 

Technical Support Document discusses the science supporting the agencies’ 

determination that waters meeting the definition of “tributary” have a significant 

nexus because they significantly affect the chemical, physical, and biological 

integrity of traditional navigable waters, interstate waters, and the territorial seas. 

Section I of the Technical Support Document describes the legal basis of the final 

rule, including its consistency with the statute and case law.

 

216 See Rapanos at 769 (Kennedy, concurring, criticizing the plurality by stating: “The merest trickle, if continuous, 

would count as a “water” subject to federal regulation . . . .”); see also Rapanos at 776-77 (Kennedy, concurring 

stating: “[B]y saying the Act covers wetlands (however remote) possessing a surface-water connection with a 

continuously flowing stream (however small), the plurality's reading would permit applications of the statute as far 

from traditional federal authority as are the waters it deems beyond the statute's reach.”).

217 See SWAANC at 168, 172.
Clean Water Rule Response to Comments – Topic 8: Tributaries

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Indiana Corn Growers Association (Doc. #14933)

8.270 The proposal defines tributaries as waters physically characterized by the presence of bed 

and banks and ordinary high water mark which contributes flow to a traditionally 

navigable water and other waters. This definition doesn’t take in to account whether 

water flows permanently, intermittently, or ephemerally.

We believe it is not appropriate or lawful for intermittent or ephemeral tributaries to be 

made categorically WOTUS. The possible scope and reach of making all ephemeral and 

intermittent tributaries jurisdictional is a stunning overreach by the Agencies’ and we 

strongly object to the definition. Drainage features in every region of Indiana commonly 

exhibit bed, bank, and ordinary high water mark characteristics that would make them 

tributaries under the proposed rule.

It is critical to realize that for those streams that are tributaries under the rule, including 

those that have drainage water in them only after a rainfall, that any field side or roadside 

drainage ditch they flow to will also be WOTUS. These roadside or field side ditches are 

found in rural areas all across Indiana and overregulation would cause unneeded burdens 

on farmers and landowners (p. 2)

Agency Response: The agencies disagree that tributaries cannot be categorically 

considered waters of the United States. See summary response for section 8.1.1. The 

agencies’ position in regard to tributaries is rooted in a science-based conclusion 

that such waters have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

conclusion. Further, Section I of the Technical Support Document discusses the 

legal issues concerning the final rule, including consistency with the statute and 

Supreme Court decisions. Paragraph (b) of the final rule excludes many features, 

including most ditches that are not relocated tributaries or excavated in 

tributaries. In addition, all existing statutory exemptions, including those at CWA 

section 404(f) for normal farming, silviculture and ranching activities and for 

maintenance of existing irrigation and drainage ditches remain in effect and 

unchanged by the final rule. See summary responses in Compendium 7 of this RTC, 

“Features and Waters Not Jurisdictional,” for a broad discussion of the final rule’s 

exclusions. See also, Section I of the Technical Support Document, which describes 

the legal basis of the final rule, including its consistency with the statute and case 

law.

National Corn Growers Association (Doc. #14968)

8.271 Farm Drainage Features as WOTUS Tributaries--NCGA believes that it is not lawful for 

intermittent or ephemeral tributaries to be made categorically WOTUS. The reasoning for 

this given in Section XX below. Aside from the issue of their lawfulness, the potential scope 

and reach of making all ephemeral and intermittent tributaries jurisdictional is simply 

breathtaking. Drainage features in every part of essentially every farming region of the 

country commonly exhibit bed, bank and ordinary high water mark characteristics that would 

make them tributaries. Many of these, as evidenced in the aerial imagery to follow, were 

likely to have been natural features (streams) that have been adapted in the agricultural 
Clean Water Rule Response to Comments – Topic 8: Tributaries

230

landscape to serve a drainage function. As the proposed rule makes clear, former tributaries 

improved for purposes such as drainage are still tributaries and remain WOTUS.

Table A-1 in Appendix One presents the calculated number of miles for many, but far 

from all, perennial, intermittent, and ephemeral streams in 20 states, as captured in the 

USGS National Hydrography Database (NHD). Using the 1:100,000 medium resolution 

dataset, which roughly approximates the perennial and intermittent streams, we estimate 

there are approximately 1.6 million miles of such streams in these 20 states alone. Using 

the 1:24,000 NHD dataset, which roughly approximates the perennial and intermittent 

streams plus about 35 percent of the ephemeral streams on average, we calculate that in 

these 20 states the number of stream miles jumps to approximately 3.5 million. That 1.9 

million mile increase in streams between the medium resolution and high resolution 

estimates is due to a large extent to the addition of the 35 percent of the ephemeral 

streams to the calculation. The increase in stream miles would certainly be significantly 

higher if 100 percent of the ephemeral streams were included in the calculation.

The US EPA has conducted a similar mapping analysis of stream miles, and the results of 

that effort are posted on the US House of Representatives Science Committee’s website. 

The national analysis presented there indicates that there are 7,339,124 miles of linear 

streams in the U.S. (including Puerto Rico). Of these, 77 percent or 5,661,337 miles are 

intermittent or ephemeral streams.218

... It is also critical to realize is that for those streams that are tributaries under the rule, 

including those that have drainage water in them only after a rainfall, that any field-side 

or roadside drainage ditch they flow to will also be WOTUS (under the proposed rule any 

ditch draining a WOTUS is also a WOTUS). If all of these mapped streams are WOTUS, 

then it is highly likely that each and every drainage ditch in this 10 square mile area is 

there is a WOTUS even if they have water in them less than permanently.

Will all of these mapped features, including the numerous ones that are ephemeral, be 

found to be a tributary as defined in the proposed rule through a formal determination? 

Every farm depicted here will share this concern as the fact of the matter is that, using 

USGS NHD data, EPA’s own “My Waters Mapper” labels features such as these as 

streams or ditches. It is impossible to say for sure from these aerial images if a channel 

with a bed, bank and ordinary high water mark will be visible when standing on the 

ground next to these features in every instance. But in many instances it is clear from a 

review of aerial imagery in farm country with the mapped stream and floodplain layers 

turned on and off that many of the mapped features very well will be WOTUS under the 

proposed rule.

For example, the images in Figure 2 below are from the “thumb” area of Michigan, east 

of Saginaw. The upper image has the mapped stream features at the 1:24,000 scale turned 

on and depicted in red, as well as the FEMA floodplains and stream buffers in light blue 

and white. The lower image is the aerial view for the same area but with the mapping 

features turned off. Clearly visible in the lower image are the actual physical channels 

and the characteristic stream-like morphology for the drainage area that lie under the 

mapped flowlines, floodplains and buffers in the upper image. Also, it is clear that these 

 

218 See http://science.edgeboss.net/sst2014/documents/epa/national2013.pdf.
Clean Water Rule Response to Comments – Topic 8: Tributaries

231

physical, tributary-like channels have in many places been straightened to facilitate 

drainage; such features are WOTUS under the proposed rule as noted above. Lastly, 

while it is hard to see in these images, it is very likely that all of the other roadside and 

field-side drainage ditches in this area are connected to the surface drainage system 

characterized by these tributaries or tributary-like system and are also themselves 

WOTUS as a result. Many of these drainage features will only have drainage water in 

them after a rainfall.
Clean Water Rule Response to Comments – Topic 8: Tributaries

232

Figure 2. Mapping analysis of area east of Saginaw, Michigan, with streams, FEMA floodplain and buffer 

layers depicted in 2 and not depicted in 3.

Figure 3 below contains photographs of farm fields at the ground level. The farm 

drainage features have a distinct channel that almost certainly would be found to have 

tributary characteristics as defiend in the proposed rule.
Clean Water Rule Response to Comments – Topic 8: Tributaries

233

Figure 3 – farm drainage features in farm fields with tributary-like channels

As noted above, such drainage features are found in farm fields across the US. NCGA 

encourages the Agencies, before finalizing this rulemaking, to conduct a thorough and 

accurate field review of this class of features across the country and to provide NCGA 

and the larger agriculture community with its own assessment of the likely jurisdictional 

consequences for these features. Lacking such an assessment we are convinced that the 

Agencies will be doing this rulemaking in the absence of critical and important 

information to help them and the public assess the practical effects of the policies being 

advanced in the rule. (p. 6-11)
Clean Water Rule Response to Comments – Topic 8: Tributaries

234

Agency Response: See summary responses for sections 8.1.1, 8.2 and 8.4. The final 

rule categorically considers tributaries, as defined in the rule that are not otherwise 

excluded under paragraph (b) to be waters of the United States. Paragraph (b) of 

the final rule excludes many features, including most ditches that are not relocated 

tributaries or excavated in tributaries. In addition, all existing statutory exemptions, 

including those at CWA section 404(f) for normal farming, silviculture and ranching 

activities and for maintenance of existing irrigation and drainage ditches remain in 

effect and unchanged by the final rule. See summary responses in Compendium 7 of 

this RTC, “Features and Waters Not Jurisdictional,” for a broad discussion of the 

final rule’s exclusions. See also, Section I of the Technical Support Document, which 

describes the legal basis of the final rule, including its consistency with the statute 

and case law. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ determination that waters meeting the definition of 

“tributary” have a significant nexus because they significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas. 

8.272 ...we think it is unlawful for any of the following to be deemed WOTUS categorically:

1. Ephemeral or Intermittent or Tributaries. Ephemeral and intermittent tributaries should 

not be categorically WOTUS. It is possible that, on a case-by-case basis, some of them 

could be found to have a significant (properly defined and specified) nexus to the TNWs. 

But it is not appropriate or lawful, under Justice Kennedy’s test, to treat them all as 

categorically WOTUS. Such tributaries, including ephemeral and intermittent ditches, 

could well have insufficient volumes of water moving through them to support the 

finding that they have a significant nexus with traditionally navigable waters 

downstream. Such a significant nexus finding cannot be made categorically, for all such 

tributaries, as that could easily ignore the facts in a particular tributary’s situation that 

would reject a significant nexus finding. Making a categorical finding of a significant 

nexus for tributaries with minor flow volumes amounts to little more than speculation as 

to the connection’s substantive effects in specific instances. 

... (p. 20-21)

Agency Response: The agencies disagree that tributaries cannot be categorically 

considered waters of the United States. See summary response for section 8.1.1. The 

agencies’ position in regard to tributaries is rooted in a science-based conclusion 

that such waters have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

conclusion. Further, Section I of the Technical Support Document discusses the 

legal issues concerning the final rule, including consistency with the statute and 

Supreme Court decisions.
Clean Water Rule Response to Comments – Topic 8: Tributaries

235

Colorado Cattlemen’s Association (Doc. #15068) 

8.1 In laymen’s terms the phrase “regardless of their size or how frequently they flow” means 

“all.” The proposed rule makes all streams federal. Justice Kennedy was clear that “other 

waters” cannot contain those waters that have little or no connection.

219 There are many 

streams across the country that have little or no connection to TNWs, which make the 

agencies’ blanket rule covering all streams beyond the purview of the CWA. If in fact all 

streams are now federal waters, despite their lack of a significant connection to TNWs, it 

raises a constitutional question about the CWA itself. (p. 5)

Agency Response: See summary response for Section 8.1.1 The final rule 

categorically considers tributaries, as defined in the rule that are not otherwise 

excluded under paragraph (b) to be waters of the United States. Section VII of the 

Technical Support Document discuss the science supporting the agencies’ 

determination that waters meeting the definition of “tributary” have a significant 

nexus because they significantly affect the chemical, physical, and biological 

integrity of traditional navigable waters, interstate waters, and the territorial seas. 

Section I of the Technical Support Document describes the legal basis of the final 

rule, including its consistency with the statute and case law.

North Carolina Farm Bureau Federation (Doc. #15078)

8.2 "Tributaries" cannot and should not include ephemeral drainages and features.

The definition of a "tributary" is one of the most expansive and problematic terms in the 

proposed rule. The American Heritage Dictionary (1982) defines "tributary" as "a stream 

or river flowing into a larger stream or river." This common understanding of "tributary" 

simply does not include "ephemeral" drainages that only channel stormwater after heavy 

rains. Most of the time, ephemeral drainages are dry land-they are not flowing rivers or 

streams. Yet, the Agencies insist that "[t]ributaries that are small, flow infrequently, or 

are of substantial distance from the nearest (a)(l) through (a)(4) water, e.g., headwater 

perennial, intermittent, and ephemeral tributaries" are nevertheless part of the tributary 

network regulated by this proposal. (79 Fed. Reg. at 22,206.)

The Agencies have proposed an overly broad "tributary" definition focusing on the 

presence of a bed, bank, ordinary high water mark (OHWM) and any minimal amount of 

flow that eventually reaches (directly or through any number of other paths and channels) 

to a creek or stream that in turn ultimately flows to a traditional navigable water. The rule 

would provide: "The term tributary means a water physically characterized by the 

presence of a bed and banks and ordinary high water mark, as defined at 33 CFR 

328.3(e), which contributes flow, either directly or through another water, to a water 

identified in paragraphs (a)(l) through (4) of this section." (p. 6-7)

Agency Response: See summary response for sections 8.1.1 and 8.4. The definition 

of “tributary” in the final rule requires that flow must be of sufficient volume, 

frequency, and duration to create the physical characteristics of bed and banks and 

an ordinary high water mark. The Agencies believe that grounding the definition of 

 

219 Rapanos, J. Kennedy, at 10.
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236

“tributary” in the final rule to the above referenced specific physical features will 

help clarify the distinction between covered tributaries and erosional features, and 

simplify implementation of the final rule. Section VII of the Technical Support 

Document further discusses the science supporting the agencies’ conclusion.

Weyerhaeuser Company (Doc. #15392)

8.3 Finally, the requirement that a tributary contribute flow, directly or indirectly, to a 

downstream jurisdictional water is no requirement at all because any volume and 

frequency of flow will suffice and proximity to the downstream jurisdictional water is 

irrelevant.220 Any low areas in a forest where stormwater naturally channels could be a 

“water of the United States” so long as they carry stormwater that eventually reaches a 

traditional navigable water, interstate water, territorial sea, or impoundment. As a 

practical consequence, forest owners likely must presume that intermittent and ephemeral 

features on their lands meet the “contributes flow” requirement simply by virtue of the 

fact that water flows downhill.

The categorical assertion of jurisdiction over all tributaries regardless of flow 

characteristics or proximity to navigable waters will have profound implications for 

Weyerhaeuser and other private forest owners. Routinely, forestry operations are 

undertaken near intermittent and ephemeral streams, as well as many other drainage 

features that can be in close proximity to each other. The proposed rule would expand the 

Agencies’ CWA jurisdiction to include all such features and, as a consequence, forest 

owners would need to respond, likely be establishing expanded riparian management 

zones, which would remove large acreages from forest management and causing 

significant financial hardship for forest owners. In addition, forest owners would be faced 

with the specter of increased enforcement actions and citizen suits. (p. 5)

Agency Response: See summary response for section 8.1.1. The agencies’ position 

in regard to tributaries is rooted in a science-based conclusion that such waters have 

a significant nexus either individually or in the aggregate with traditional navigable 

waters, interstate waters, and the territorial seas. Section VII of the Technical 

Support Document discusses the science supporting the agencies’ conclusion. 

Further, Section I of the Technical Support Document discusses the legal issues 

concerning the final rule, including consistency with the statute and Supreme Court 

decisions. All existing statutory exemptions, including those at CWA section 404(f) 

for normal farming, silviculture and ranching activities and for maintenance of 

existing irrigation and drainage ditches remain in effect and unchanged by the final 

rule.

Jensen Livestock and Land LLC (Doc. #15540)

8.4 Jensen Livestock and Land LLC. strongly assert that only stream features with “relatively 

permanent, standing or continuous” flow, pursuant to Justice Scalia’s Plurality Opinion in 

Rapanos should be included in the definition of “tributary.”221 This would limit the 

 

220 See 79 Fed. Reg. at 22,206.

221 Rapanos, J. Scalia, at 20 (In sum, on its only plausible interpretation, the phrase :the waters of the United States”
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237

number of features that can be considered “tributaries” to those that could actually have a 

significant impact on the water quality of downstream waters, pursuant to the decision in 

Rapanos.

222 It would also provide needed clarity to the ranching community. Jensen 

Livestock and Land LLC strongly assert that intermittent and ephemeral features should 

NOT be considered “waters of the U.S.” because these features are best regulated by 

states and localities, and were not intended by Congress to be regulated by the federal 

government. EPA’s own Rapanos Guidance states, “Justice Scalia emphasizes that 

relatively permanent waters do not include tributaries ‘whose flow is coming and going at 

intervals...broken, fitful.’”223 While Jensen Livestock and Land LLC assert with the 

guidance’s ultimate position of being able to claim jurisdiction over intermittent or 

ephemeral streams under a significant nexus analysis, we request the agencies explain the 

rationale of this significant policy shift. (p. 10)

Agency Response: See summary response for section 8.1.1. The agencies’ position 

in regard to tributaries is rooted in a science-based conclusion that such waters have 

a significant nexus either individually or in the aggregate with traditional navigable 

waters, interstate waters, and the territorial seas. Section VII of the Technical 

Support Document discusses the science supporting the agencies’ conclusion. 

Further, Section I of the Technical Support Document discusses the legal issues 

concerning the final rule, including consistency with the statute and Supreme Court 

decisions. All existing statutory exemptions, including those at CWA section 404(f) 

for normal farming, silviculture and ranching activities and for maintenance of 

existing irrigation and drainage ditches remain in effect and unchanged by the final 

rule.

Dairy Cares (Doc. #16471)

8.5 The Proposed Rule would allow the Agencies to assert jurisdiction over a wide range of 

tributaries without first demonstrating that a nexus exists between the tributary and a 

more “traditional” WOTUS. This approach contravenes Justice Kennedy’s concurring 

opinion in Rapanos, where he explained that in order to assert jurisdiction over a 

particular body of water, the Agencies must demonstrate a significant nexus exists to a 

water that is navigable in the traditional sense.224 Specifically, the Agencies’ definition of 

“tributary” would assert jurisdiction over a significant class of waters, rather than a 

particular body of water, by simply relying on the assumption that flow from tributaries 

automatically has a significant nexus to a more traditional navigable water. This 

assumption belies the idea and requirement that a significant nexus be demonstrated. 

Further, the assumption removes consideration of the significance of the tributary’s affect 

on the traditional WOTUS; instead, the Agencies merely assume that the contribution of 

flow will be significant. Regardless of whether an effect rises to a sufficient level of 

significance, the assumption also relies on the premise that flow actually affects a 

 

includes only those relatively permanent, standing or continuously flowing bodies of water forming geographic 

features “that are described in ordinary parlance as “stream[,]...oceans, rivers, [and] lakes.”).

222 Id.

223 EPA, Clean Water Act Jurisdiction Following the U.S. Supreme Court’s Decision in Rapanos v. United States &

Carabell v. United States, at 7 (Dec. 2, 2008).

224 Rapanos, 547 U.S. at 742.
Clean Water Rule Response to Comments – Topic 8: Tributaries

238

traditional WOTUS. Conceding that flow—even if ephemeral or intermittent—may 

establish a hydrologic connection with a jurisdictional water, the Proposed Rule fails to 

address whether, in fact, the flow affects the traditional WOTUS and whether the effect 

of the flow is sufficiently significant for purposes of the U.S. Supreme Court’s significant 

nexus test.

The Proposed Rule’s definition of “tributary” could significantly impact dairy farms and 

operations. As discussed above, dairy facilities can include several different types of 

water storage, processing, and conveyance facilities. Dairy farms use ditches and 

channels to move water from storage ponds to irrigate pastures, provide water to animals, 

wash facilities, and treat and spread waste. The Proposed Rule’s broad attempt to make 

jurisdictional all tributaries raises grave concerns regarding the extent to which state and 

federal regulators will rely on the new definition of “tributary” to assert jurisdiction over 

these types of dairy facilities and operations not previously regulated. If ditches and 

channels on dairy operations are to be regulated under the Proposed Rule, dairy farmers 

and operators will be subject to an additional burdensome layer of expensive regulation 

that is likely to affect economic productivity. Although the Proposed Rule attempts to 

protect the categorical exclusions, Dairy Cares is concerned that the definition of 

“tributary,” whether interpreted by the Agencies or the courts, will ultimately swallow the 

purpose and applicability of the categorical exclusions.

Accordingly, Dairy Cares requests the Agencies revise the Proposed Rule to be more 

consistent with Justice Kennedy’s interpretation of WOTUS in Rapanos, namely to 

require case-by-case analysis of tributaries to determine whether specific tributaries 

actually affect significantly the chemical, physical, or biological properties of the 

receiving WOTUS. Additionally, Dairy Cares requests the Agencies provide greater 

certainty—in the language of the definition—on how the definition of “tributary” will not 

affect a dairy facility’s ability to claim cover under the categorical exclusions. (p. 3-4)

Agency Response: See summary responses for sections 8.1.1, 8.2 and 8.4. The 

agencies disagree that tributaries should be evaluated on a case-by-case basis. 

Section I of the Technical Support Document describes the legal basis of the final 

rule, including its consistency with the statute and case law. Section VII of the 

Technical Support Document discusses the science supporting the agencies' 

determination that waters meeting the definition of "tributary" have a significant 

nexus because they significantly affect the chemical, physical, and biological 

integrity of traditional navigable waters, interstate waters, and the territorial seas. 

Paragraph (b) of the final rule excludes many features, including most ditches that 

are not relocated tributaries or excavated in tributaries. In addition, all existing 

statutory exemptions, including those at CWA section 404(f) for normal farming, 

silviculture and ranching activities and for maintenance of existing irrigation and 

drainage ditches remain in effect and unchanged by the final rule. See summary 

responses in Compendium 7 of this RTC, "Features and Waters Not 

Jurisdictional," for a broad discussion of the final rule's exclusions. 

Agribusiness Association of Kentucky et al. (Doc. #18005)

8.6 The definition of a "tributary" is one of the most expansive and problematic terms in the 

proposed rule. The American Heritage Dictionary (1982) defines "tributary" as "a stream 
Clean Water Rule Response to Comments – Topic 8: Tributaries

239

or river flowing into a larger stream or river." This common understanding of "tributary" 

simply does not include "ephemeral" drainages that only channel stormwater after heavy 

rains. Most of the time, ephemeral drainages are dry land—they are not flowing rivers or 

streams. Yet, the Agencies insist that "[t]ributaries that are small, flow infrequently, or 

are of substantial distance from the nearest (a)(1) through (a)(4) water, e.g., headwater 

perennial, intermittent, and ephemeral tributaries" are nevertheless part of the tributary 

network regulated by this proposal. 79 Fed. Reg. at 22,206. (p. 6)

Agency Response: See summary response for sections 8.1.1 and 8.4. The definition 

of "tributary" in the final rule requires that flow must be of sufficient volume, 

frequency, and duration to create the physical characteristics of bed and banks and 

an ordinary high water mark. The Agencies believe that grounding the definition of 

"tributary" in the final rule to the above referenced specific physical features will 

help clarify the distinction between covered tributaries and erosional features, and 

simplify implementation of the final rule. Section VII of the Technical Support 

Document further discusses the agencies determination that waters meeting the 

definition of "tributary" have a significant nexus because they significantly affect 

the chemical, physical, and biological integrity of traditional navigable waters, 

interstate waters, and the territorial seas.

Frasier Farms (Doc. #18660)

8.7 On my ranch, I can identify an area that within a few hundred yards includes intermittent 

and ephemeral streams, rills and gullies, as well as a natural and undrained swale. By 

definition, some of these topographies would be considered jurisdictional and some not, 

yet all contribute to the same watershed. If there were determined to be a significant 

nexus between the features, then the entirety of the sample area – and a good deal of my 

29,000 acre ranch – would fall under EPA jurisdiction per the Clean Water Act. It is 

impractical to regulate and monitor the vast expanses of North America that may be 

subject to new jurisdictional authority and leaving private land managers in uncertainty 

will lead to needless costs and unwarranted precautions. It is imperative that any rule 

change be objectively defined in measurable terms, so that regulators and the regulated 

community may clearly anticipate what lands and waters are impacted and which are 

exempt. Any Significant Nexus must be demonstrate a physical connectivity with the 

evidence of science-based proof. The Proposed Rule must provide descriptive language 

to define how connectivity will be determined. (p. 1)

Agency Response: See summary response for sections 8.1.1 and 8.4. The definition 

of “tributary” in the final rule requires that flow must be of sufficient volume, 

frequency, and duration to create the physical characteristics of bed and banks and 

an ordinary high water mark. The Agencies believe that grounding the definition of 

“tributary” in the final rule to the above referenced specific physical features will 

help clarify the distinction between covered tributaries and erosional features, and 

simplify implementation of the final rule. Section VII of the Technical Support 

Document further discusses the agencies determination that waters meeting the 

definition of “tributary” have a significant nexus because they significantly affect 

the chemical, physical, and biological integrity of traditional navigable waters, 

interstate waters, and the territorial seas.
Clean Water Rule Response to Comments – Topic 8: Tributaries

240

Ohio Pork Council (Doc. #19554)

8.8 In their WOTUS proposal, EPA and the Corps have defined for the first time what they 

consider to be a tributary. Making all ephemeral and intermittent tributaries jurisdictional 

is simply extraordinary. In practice, relying on the plain English meanings of the 

proposed rule, literally millions of drainage features in every part of every farming region 

of the country will have characteristics – a bed, bank and ordinary high water mark – that 

would make them tributaries. This will expand the jurisdiction of EPA and the Corps in 

an unprecedented manner that conflicts with both the clear direction and intent of the 

Supreme Court’s prior numerous decisions that sought to limit the federal jurisdiction 

over private lands. (p. 2)

Agency Response: See summary response for Section 8.1.1. The final rule 

categorically considers tributaries, as defined in the rule and that are not otherwise 

excluded under paragraph (b) to be waters of the United States. Section VII of the 

Technical Support Document discuss the science supporting the agencies’ 

determination that waters meeting the definition of “tributary” have a significant 

nexus because they significantly affect the chemical, physical, and biological 

integrity of traditional navigable waters, interstate waters, and the territorial seas.

Section I of the Technical Support Document describes the legal basis of the final 

rule, including its consistency with the statute and case law.

Georgia Department of Transportation (Doc. #14282.1)

8.9 A. "Reasonably permanent flow"

The proposed rule defines "tributary" without any reference to the frequency or extent of 

flow. Tributaries are defined to include any water that is "physically characterized by the 

presence of a bed and banks and ordinary high water mark" and that "contributes flow, 

either directly or through another water, to a water identified in paragraphs (a)(1) through 

(4) of this section ." (79 Fed. Reg. 22263). If a water meets these criteria, it is 

jurisdictional by rule.

By contrast, the 2008 Guidance deemed tributaries as jurisdictional by rule - that it, 

without the need for a significant-nexus determination - only when the tributaries "are 

relatively permanent where the tributaries typically flow year-round or have continuous 

flow at least seasonally (e .g., typically three months)."

225 That guidance also specifically 

noted that "relatively permanent" waters "do not include ephemeral tributaries which 

flow only in response to precipitation and intermittent streams which do not typically 

flow year-round or have continuous flow at least seasonally. However, CWA jurisdiction 

over these waters will be evaluated under the significant nexus standard described 

below."226

The omission of the "relatively permanent" requirement would substantially broaden the 

universe of tributaries deemed jurisdictional by rule. In effect, a tributary would be 

deemed jurisdictional by rule without any consideration of the flow regime in that

 

225 2008 Guidance, p. 6 (emphasis added).

226 Id. at 7.
Clean Water Rule Response to Comments – Topic 8: Tributaries

241

tributary. A stream with intermittent or even ephemeral flow could be found 

jurisdictional by rule, simply because it has an indirect, infrequent downstream 

connection to a jurisdictional water. We believe this approach is inconsistent with the 

intent of the proposed rule: to clarify, not expand, the scope of the federal jurisdiction 

under the Clean Water Act.227

Recommendation: We recommend modifying the proposal rule to ensure that tributaries 

are evaluated under the same criteria used in the 2008 Guidance: tributaries should be 

deemed jurisdictional by rule only if they have a "relatively permanent flow" (or an 

equivalent requirement, such as "perennial flow"), meaning that they "typically flow 

year-round or have continuous flow at least seasonally (e .g., typically three months)." If 

relatively permanent flow is not found, the tributary still could be evaluated under the 

significant-nexus test, as was the case under the 2008 Guidance.228 (p. 5-6)

Agency Response: See summary responses for sections 8.1.1 and 8.1.2. The final 

rule eliminates the need to identify a water as relatively-permanent, or conduct a 

significant nexus determination for each tributary. Instead, the final rule establishes 

categorical jurisdiction over all waters that meet the definition of "tributary" and 

that are not excluded in paragraph (b). Section I of the Technical Support 

Document further discusses the legal issues concerning the final rule, including 

consistency with the statute and Supreme Court decisions. Section VII of the 

Technical Support Document discusses the science supporting the agencies' 

determination that waters meeting the definition of "tributary" have a significant 

nexus because they significantly affect the chemical, physical, and biological 

integrity of traditional navigable waters, interstate waters, and the territorial seas. 

8.10 B. "Do not contribute flow, either directly or through another water"

As discussed above in the context of the ditch exclusions, we are concerned that the 

phrase "contributes flow, either directly or through another water" could be interpreted 

very broadly, so that it encompasses waters that have a highly remote or tenuous 

downstream connection to other jurisdictional waters.

Recommendation: As noted above, we recommend clarifying that a tributary does not 

"contribute flow' to another water if its only connection to that water is "insubstantial or 

remote." We recommend making this change regardless of whether the definition is 

modified to include a requirement for "relatively permanent" flow. (p. 6)

Agency Response: See summary response for section 8.1.1. The final rule 

establishes categorical jurisdiction over all waters that meet the definition of 

“tributary” and that are not excluded in paragraph (b). This position is rooted in a 

 

227 See "EPA and Army Corps of Engineers Clarify Protection for Nation's Streams and Wetlands: Agriculture's

Exemptions and Exclusions from Clean Water Act Expanded by Proposal" (press release), issued March 25, 2014, 

available at: http://www2.epa.gov/uswaters. The same website also states that the proposed rule "Does Not

Broaden Coverage of the Clean Water Act."

228 See Guidance, p. 7 ("Therefore, 'relatively permanent' waters do not include ephemeral tributaries which flow 

only in response to precipitation and intermittent streams which do not typically flow year-round or have continuous 

flow at least seasonally. However, CWA jurisdiction over these waters will be evaluated under the significant nexus 

standard described below.").
Clean Water Rule Response to Comments – Topic 8: Tributaries

242

science-based conclusion that such waters have a significant nexus either 

individually or in the aggregate with traditional navigable waters, interstate waters, 

and the territorial seas. Section VII of the Technical Support Document discusses 

the science supporting the agencies’ conclusion. 

Charlotte-Mecklenburg Storm Water Services (Doc. #3431)

8.11 Within the definition of “tributary” the term “flow” is not clearly defined, since even 

ephemeral ditches contribute flow during wet weather... CMSWS recommends defining 

“flow” as at least intermittent flow... (p. 2-3)

Agency Response: See summary response for sections 8.1.1, 8.2 and 8.4. The 

definition of “tributary” in the final rule requires that flow must be of sufficient 

volume, frequency, and duration to create the physical characteristics of bed and 

banks and an ordinary high water mark. This position is rooted in a science-based 

conclusion that such waters have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion. In addition, paragraph (b) of the final rule 

excludes many features from consideration as waters of the United States, including 

most ditches that are not relocated tributaries or excavated in tributaries and 

stormwater control features created in dry land. See summary responses in 

Compendium 7 of this RTC, “Features and Waters Not Jurisdictional,” for a broad 

discussion of the final rule’s exclusions features.

Red River Joint Water Resource District (Doc. #4227)

8.12 ...the proposed definition of "tributary" is alarmingly expansive. The proposed rules 

define "tributary" to include any "water" with streamlike physical characteristics, 

including "a bed, banks, and ordinary high water mark" that "contributes flow" directly or 

through "another water" to navigable, interstate, or territorial waters, or an impoundment 

of any of those. The new definition could conceivably include even manmade channels 

that may "contribute flow" at some point to any downstream jurisdictional water. For 

example, consider a manmade pond that overflows during a high water event, then flows 

overland and discharges into a downstream manmade pond; then the downstream 

manmade pond also overflows, flows overland during a high water event, and discharges 

into a manmade ditch; then the manmade ditch discharges into another downstream ditch 

that ultimately discharges into a tributary of a tributary of a navigable/jurisdictional 

water, the new rule suggests the original manmade upstream pond is jurisdictional under 

the definition of "tributary." This seemingly ridiculous example of the breadth of the 

proposed rules may not be the intent of the rules, but would be a consequence of the 

rules. Despite EPA's suggestions otherwise, the new language in the rules that defines 

"tributary" is extremely expansive and does, in fact, greatly extend the jurisdiction of 

EPA and the Corps under the CWA. (p. 2)

Agency Response: See summary response for sections 8.1.1, 8.2 and 8.4. Many 

man-made and man-altered tributaries, despite human manipulation, continue to 

have chemical, physical, or biological connections downstream and serve important 

functions downstream. Section VII of the Technical Support Document discusses 
Clean Water Rule Response to Comments – Topic 8: Tributaries

243

man-made or man-altered tributaries and their effect on the physical, chemical and 

biological integrity of traditional navigable waters, interstate waters and the 

territorial seas. However, the agencies’ longstanding practice is to view stormwater 

water control measures that are not built in “waters of the United States” as nonjurisdictional. Nothing in the proposed rule was intended to change that practice, 

and the final rule is consistent with that intent. Paragraph (b) of the final rule 

excludes many features from consideration as waters of the United States, including 

most ditches that are not relocated tributaries or excavated in tributaries and 

stormwater control features created in dry land. See summary responses in 

Compendium 7 of this RTC, “Features and Waters Not Jurisdictional,” for a broad 

discussion of the final rule’s exclusions features.

Florida Federation of Garden Clubs (Doc. #5725)

8.13 We support the Agencies’ proposal to define all tributaries as “waters of the United 

States,” including headwaters and small streams that may only flow seasonally. 

Headwater streams provide most of the flow to downstream streams and rivers, and make 

up 29 percent of Florida’s stream miles. Intermittent and ephemeral streams may only 

flow during parts of the year, but they support water quality in downstream waters by 

filtering pollutants and capturing nutrients and make up 12 percent of Florida’s stream 

miles.

These streams are also critical habitat for fish and other aquatic species. Headwater and 

seasonal streams also feed the drinking water sources of 117 million Americans. 

Clarifying that all tributary streams, regardless of size or frequency of flow are covered 

under the Clean Water Act will restore protections to 580 miles of headwater, intermittent 

and ephemeral streams in Florida that supply drinking water sources. (p. 2)

Agency Response: The agencies agree with the commenter that headwater 

streams provide important functions that support the chemical, physical and 

biological integrity of downstream waters. Intermittent and ephemeral streams that 

meet the final rule’s definition “tributary” are considered “waters of the United 

States.” See summary response to section 8.1.1.

Beaufort County Stormwater Utility, South Carolina (Doc. #7326.1)

8.14 II) “Tributaries” – The current regulations provide for tributaries of a WOTUS as being 

WOTUS, although “tributary” is not defined. The proposed rule keeps the same reference 

but has an expansive definition of what a tributary is, including man-altered or man-made 

ponds, canals and ditches, with limited exceptions.

Agency Response: See summary responses for sections 8.1.1, 8.2 and 8.4. The final 

rule establishes categorical jurisdiction over all waters that meet the definition of 

“tributary” and that are not excluded in paragraph (b). Many man-made and manaltered tributaries, despite human manipulation, continue to have chemical, 

physical, or biological connections downstream meet the rule’s definition of 

“tributary.” Section VII of the Technical Support Document discusses man-made or 

man-altered tributaries and their effect on the physical, chemical and biological 

integrity of traditional navigable waters, interstate waters and the territorial seas. 

However, paragraph (b) of the final rule excludes many features from consideration 
Clean Water Rule Response to Comments – Topic 8: Tributaries

244

as waters of the United States, including most ditches that are not relocated 

tributaries or excavated in tributaries and stormwater control features created in 

dry land. See summary responses in Compendium 7 of this RTC, “Features and 

Waters Not Jurisdictional,” for a broad discussion of the final rule’s exclusions.

8.15 The proposed rule defines “tributary” without any reference to the frequency or extent of 

flow. Tributaries are defined to include any water that is “physically characterized by the 

presence of a bed and banks and ordinary high water mark” and that “contributes flow, 

either directly or through another water, to a water identified in paragraphs (a)(1) through 

(4) of this section.” [79 Federal Register (FR) 22263]. If a water meets these criteria, it is 

jurisdictional by rule. Previous guidance deemed tributaries as jurisdictional by rule 

without the need for a significant-nexus determination only when the tributaries “are 

relatively permanent where the tributaries typically flow year-round or have continuous 

flow at least seasonally (e.g., typically three months).” That guidance also specifically 

noted that “relatively permanent” waters “do not include ephemeral tributaries which 

flow only in response to precipitation and intermittent streams which do not typically 

flow year-round or have continuous flow at least seasonally.” However, CWA 

jurisdiction over these waters will be evaluated under the significant nexus standard. The 

omission of the “relatively permanent” requirement would substantially expand the 

number of tributaries that could be deemed jurisdictional by rule. In effect, a tributary 

would be deemed jurisdictional by rule without any consideration of the flow regime in 

that tributary. A stream with intermittent or even ephemeral flow could be found 

jurisdictional by rule, simply because it has an indirect, infrequent downstream 

connection to a jurisdictional water. The phrase “contributes flow, either directly or 

through another water” could be interpreted very broadly, so that it encompasses waters 

that have a highly remote or tenuous downstream connection to other jurisdictional 

waters.

Recommendation: The Final Rule should be modified to say that tributaries are 

jurisdictional by rule only if they have a “relatively permanent flow” (or an equivalent 

requirement, such as “perennial flow”), meaning that they “typically flow year-round or 

have continuous flow at least seasonally (e.g., typically three months).” If relatively 

permanent flow is not found, the tributary still could be evaluated under the significantnexus test. This would be consistent with the 2008 Guidance Document. Also, it should 

be clarified in the Final Rule that a tributary does not “contribute flow” to another water 

if its only connection to that water is “insubstantial or remote.” (p. 2)

Agency Response: See summary responses for sections 8.1.1 and 8.1.2. The final 

rule eliminates the need to identify a water as relatively-permanent, or conduct a 

significant nexus determination for each tributary. Instead, the final rule establishes 

categorical jurisdiction over all waters that meet the definition of "tributary" and 

that are not excluded in paragraph (b). Section I of the Technical Support 

Document further discusses the legal issues concerning the final rule, including 

consistency with the statute and Supreme Court decisions. Section VII of the 

Technical Support Document discusses the science supporting the agencies' 

determination that waters meeting the definition of "tributary" have a significant 

nexus because they significantly affect the chemical, physical, and biological 

integrity of traditional navigable waters, interstate waters, and the territorial seas.
Clean Water Rule Response to Comments – Topic 8: Tributaries

245

Black Hills Corporation (Doc. #6248)

8.16 The proposed draft rule definition of "tributary" does not speak to the frequency of water 

flow. Ignoring the frequency of flow could mean that any minimal hydrologic connection 

could be deemed jurisdictional, encompassing any land-locked area that has ephemeral or 

intermittent water flows. This definition can include any number of streams, ditches, 

potholes, dry streambeds, impoundments, and other natural depression. If the definition 

of "tributary" is not better defined, costs to review and permit environmentally and 

economically insignificant water features may skyrocket. (p. 4)

Agency Response: See summary responses for sections 8.1.1. The rule definition 

of “tributary” requires that flow be of sufficient volume, frequency, and durations 

to create physical characteristics of bed and banks and an OHWM. The agencies’ 

position in regard to tributaries is rooted in a science-based conclusion that such 

waters have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

conclusion. Paragraph (b) of the final rule outlines numerous exclusions for features 

that will not be waters of the United States, including most ditches that are not 

relocated tributaries or excavated in tributaries, water-filled depressions created in 

dry land incidental to mining or construction activity and erosional features, 

including gullies, rills, and other ephemeral features that do not meet the definition 

of “tributary.”

Northwest Colorado Council of Governments Water Quality/Quantity Committee (Doc. #10187)

8.17 Mountain streams in the western United States often are diverted into pipes and tunnels 

for portions of their reach and then resurface downstream to join the main stream once 

again. The proposed rule correctly recognizes that such modifications do not alter the 

interconnectivity of a tributary to navigable waters and should not change the 

jurisdictional status of the tributary. However, QQ tributaries that flow through shale 

fields or other natural barriers should not be categorically defined as waters of the United 

States because those waters may have no connection to waters of the United States. 

Instead, QQ recommends that tributaries interrupted by natural features be evaluated 

under the significant nexus test. (p. 4)

Agency Response: See summary responses for sections 8.1.1 and 8.3. Under the 

final rule, a water that otherwise qualifies as a tributary under this definition does 

not lose its status as a tributary if, for any length, there are one or more man-made 

breaks (such as bridges, culverts, pipes, or dams), or one or more natural breaks 

(such as wetlands at the head of or along the run of a stream, debris piles, boulder 

fields, or a stream that flows underground) so long as a bed and banks and an 

ordinary high water mark can be identified upstream of the break.

8.18 The proposed definition of “tributaries” would include tributary streams whose flow is 

due to intercepted groundwater (as long as they have a bed, bank and ordinary high water 

mark). These pristine streams fed by groundwater are common in the headwaters region, 

where they are often important sources of drinking water. QQ supports the inclusion of 

headwaters springs fed from groundwater, and encourages the EPA and Corps to clarify 
Clean Water Rule Response to Comments – Topic 8: Tributaries

246

that groundwater-fed tributaries are specifically included in this proposed definition. (p. 

4)

Agency Response: See summary response for sections 8.1.1. The definition of 

"tributary" in the final rule emphasizes the importance of flow; specifically, it 

requires flow be of sufficient volume, frequency, and durations to create physical 

characteristics of bed and banks and an OHWM. A great majority of headwater 

streams are covered by this definition, and waters that are adjacent to a tributary at 

the upper limit of the channel can be jurisdictional as adjacent waters. See sections 

IV(G) and IV(H) of the final rule preamble. Further, while the agencies have never 

interpreted "waters of the United States" to include groundwater, this exclusion 

does not apply to surface expressions of groundwater, such as where groundwater 

emerges on the surface and becomes baseflow in streams or spring fed ponds.

Section III(C) of the final rule preamble and Section VII of the Technical Support 

Document.

Mohave Electric Cooperative, Inc. (Doc. #10953)

8.19 What is very much unclear in the Proposed Rule is the level of effort that must be made 

to demonstrate that a given ephemeral wash, no matter how small or how distant from a 

key receiving water, "contributes flow" to that key receiving water. Does the phrase 

"contributes flow" imply continual discharge to a key receiving water (either directly or 

indirectly)? Annual discharge? What about ephemeral washes that can only be 

demonstrated to discharge flows into a key receiving water in a 100-year storm event? Or 

is the threshold the "one molecule of water" test that the U.S. Army Corps of Engineers 

(Corps) has used in the past, i.e. if a single molecule of water can reach a key receiving 

water then the wash would be considered to "contribute flow"?

The difficulties of determining the tributary (and therefore jurisdictional) status of 

ephemeral washes in the Proposed Rule will therefore still require case-specific analysis, 

and perhaps a more robust analysis than is currently required for a significant nexus 

analysis. If the stated goal of the Proposed Rule is to provide clarity to regulators and the 

regulated community, the interpretation of the plurality in Rapanos should be applied. 

The Plurality clearly articulated the term "waters of the United States" as covering 

"relatively permanent, standing or continuously flowing bodies of water that are 

connected to traditional navigable waters, as well as wetlands with a continuous surface 

connection to such relatively permanent water bodies." (p. 4)

Agency Response: Agency Response: See summary response for sections 8.1.1 and 

8.4. The definition of “tributary” in the final rule requires that flow must be of 

sufficient volume, frequency, and duration to create the physical characteristics of 

bed and banks and an ordinary high water mark. If a water lacks sufficient flow to 

create such characteristics, it is not considered “tributary” under this rule. Section 

VII of the Technical Support Document further discusses the science supporting the 

agencies’ conclusion that all waters that meet the definition of “tributary” and that 

are not excluded in paragraph (b), have a significant nexus either individually or in 

the aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. For these reasons, the final rule does not require that a case-by-case 

determination be made regarding whether an ephemeral or tributary stream has a 
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247

significant nexus to navigable waters. Instead, the case-by-case inquiry is whether 

or not the water under consideration meets the rule’s definition of “tributary” and 

is not excluded by paragraph (b). See also summary response for “Relevance of 

Flow Regime” above, particularly subsections on jurisdiction over intermittent and 

ephemeral waters, the legality of asserting jurisdiction over ephemeral waters and 

the requirement of “contribute flow.” Section I of the Technical Support Document 

discusses the legal basis of the final rule, including consistency with the statute and 

Supreme Court decisions. 

Duke Energy (Doc. #13029)

8.20 This new definition of tributary is extremely broad and extends jurisdiction to features 

that the agencies have not previously regulated, such as ephemeral drainages, ditches and 

conveyances. Under the proposed rule, the definition of tributary will cover many new 

features that are remote, intermittent, have broken or man-made connections, carry only 

minor water volumes or flow for a few hours or days following a rain event. While the 

proposed definition requires a tributary to contribute flow, that flow can be absent for any 

period of time and can also be supplied through groundwater. The definition does not 

contain any temporal limits on how often a tributary needs to contribute flow to a TNW. 

It could take years, decades, or even centuries for flow to reach a navigable water. There 

are also no geographical limits on how distant the flow that is per se jurisdictional is from 

navigable water and no need to show that the flow could carry pollutants to the navigable 

water.

Subsequently, the proposed rule does not provide any support for evaluation of the 

significance of any nexus to an (a)(1) through (a)(4) water based on the “frequency, 

magnitude, duration, predictability [or] consequences of connections” as recommended 

by EPA’s Science Advisory Board (SAB) panel.229 The definition for a tributary is also in 

conflict with Justice Kennedy’s explanation in Rapanos that frequency and duration of 

flow, as well as proximity to traditional navigable waters are important considerations in 

evaluating whether a water body has a significant nexus.230 Additionally, not all states 

currently include ephemeral waters in their regulatory program, therefore any definition 

of tributary that automatically includes waters with less than intermittent flow would be 

an expansion of jurisdiction. (p. 22-23)

Agency Response: See summary responses for sections 8.1.1 and 8.2. The 

longstanding regulatory definition of “waters of the United States” included 

“tributaries” without any limitations regarding volume or duration of flow. The 

final rule established a definition of “tributary” that requires flow to be of sufficient 

volume, frequency, and duration to create the physical characteristics of bed and 

banks and an ordinary high water mark. If a water lacks sufficient flow to create 

such characteristics, it is not considered “tributary” under this rule. Section VII of 

the Technical Support Document further discusses the science supporting the 

agencies’ conclusion that all waters that meet the definition of “tributary” and that 

are not excluded in paragraph (b), have a significant nexus either individually or in 

 

229 Draft SAB Panel Recommendations on EPA’s Connectivity Report (8-11-14 version), Page 2.

230 See Rapanos, 547 U.S. at 786
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the aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Section I of the Technical Support Document describes the legal basis of the 

final rule, including its consistency with the statute and case law. 

8.21 The proposed rule states that “a tributary connection may be traced using direct 

observation or U.S. Geological Survey maps, aerial photography or other reliable remote 

sensing information.” In a March 27, 2014 hearing before the House Appropriations 

Committee Subcommittee on Interior, Environment, and Related Agencies, 

Administrator Gina McCarthy told Chairman Rogers that EPA has “some mapping in the 

docket associated with this rule that people can access at this point.” Administrator 

McCarthy went on to say: “There has been no mapping before, there has been no 

certainty so we are identifying the rivers and streams and tributaries and other water 

bodies that science tells us is really necessary to protect the chemical, physical, and 

biological integrity of navigable waters. We have taken the opportunity to map those; we 

are certain we will get comment on them.”231 Despite the fact that Ms. McCarthy had 

apparently seen maps, no such maps were placed in the docket for the rulemaking. These 

maps were later provided to Congress in July following an additional inquiry during a 

separate hearing with EPA. However, Acting Administrator Nancy Stoner asserted that 

the maps developed by EPA using USGS data are “not to depict the scope of waters 

protected under the Clean Water Act.”232

These recently released maps, developed specifically for EPA, show the extent of water 

features identified within each state, including all stream/rivers (perennial, intermittent, 

ephemeral, unclassified), canals/ditches, lakes/ponds/reservoirs, swamp/marshes, playas, 

and washes.233 In response to inquiries about these newly-generated maps, EPA states 

“[it] has never and is not now relying on maps to determine jurisdiction under the Clean 

Water Act. The U.S. Army Corps of Engineers determines jurisdiction using detailed site 

specific information in response to requests.”234 So in addition to the confusion with 

regards to how maps should or should not be used, the statement above seems to be in 

direct conflict with the agencies’ stated purpose for the proposed rule which is to “reduce 

documentation requirements and the time currently required for making jurisdictional 

determinations [...] and reduce time and resource demanding case-specific analyses prior 

to determining.” EPA’s Associate Administrator of Public Affairs, Mr. Tom Reynolds, 

goes on to state that “[wh]ile these maps are useful tools for water resource managers, 

they cannot be used to determine Clean Water Act jurisdiction – now or ever.” If that is 

the case, what was the purpose of developing these high-resolution maps for each state? 

How will they be used or verified for accuracy? (p. 35-36)

Agency Response: The agencies have not developed, nor will they be developing, 

maps of jurisdictional waters. While a map can be a tool in, for example, tracking 

the course of a stream, whether that stream or any water is jurisdictional is a 

distinct question. The preamble addresses the use of remote sensing and mapping 

to assist in establishing the presence of water, such tools include the USGS 

 

231 http://appropriations.house.gov/calendararchive/eventsingle.aspx?EventID=373134 (46:08 to 50:00).

232 Letter from Nancy Stoner to Congressman Lamar Smith, July 28, 2014.

233 http://science.house.gov/epa-maps-state-2013#overlay-context.

234 EPA Blog by Tom Reynolds (August 28, 2014) (See Appendix E).
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249

topographic data, the USGS National Hydrography Dataset (NHD), Natural 

Resources Conservation Service (NRCS) Soil Surveys, and State or local stream 

maps, as well as the analysis of aerial photographs, and light detection and ranging 

(also known as LIDAR) data, and desktop tools that provide for the hydrologic 

estimation of a discharge sufficient to create an ordinary high water mark, such as a 

regional regression analysis or hydrologic modeling. These sources of information 

can sometimes be used independently to infer the presence of a bed and banks and 

another indicator of ordinary high water mark, or where they correlate, can be used 

to reasonably conclude the presence of a bed and banks and ordinary high water 

mark. The agencies have been using such remote sensing and desktop tools to 

delineate tributaries for many years where data from the field are unavailable or a 

field visit is not possible. However the use of any one remote sensing or desktop tool 

is usually insufficient to establish jurisdiction without studies and or significant 

experience showing that use of the remote sensing or desktop tool results in the same 

extent of jurisdiction as a field investigation in that region.

See summary also response for section 8.1.1. Determinations of whether a water 

“contributes flow” are expected to be done in a manner similar to what has been 

practiced in the field for decades. The final rule preamble discusses this process in 

greater length in Section IV.F.1.

Murray Energy Corporation (Doc. #13954)

8.22 The Proposal also advances the position that a tributary can never lose its legal status as a 

jurisdictional tributary, regardless of the presence of man-made or natural structures. Id. 

This carte blanche “no de-federalization” approach could be extremely problematic, 

especially since the Agencies have proposed no geographic or temporal limits to its 

application... (p. 11)

Agency Response: See summary responses for sections 8.1.1 and 8.3. Under the 

final rule, a water that otherwise qualifies as a tributary under the rule’s definition 

does not lose its status as a tributary if, for any length, there are one or more manmade breaks (such as bridges, culverts, pipes, or dams), or one or more natural 

breaks (such as wetlands at the head of or along the run of a stream, debris piles, 

boulder fields, or a stream that flows underground) so long as a bed and banks and 

an ordinary high water mark can be identified upstream of the break. These 

physical indicators demonstrate the water contributes sufficient flow to have a 

significant impact on downstream waters. Absence of these indicators generally 

represent the upper limit of the tributary. Section IV of the Technical Support 

Document discusses further the science that supports the agencies’ conclusion. 

Further, the agencies will continue existing practice of making case by case 

determinations of the length of break in OHMD that does not sever the connection 

to downstream waters.

County of San Diego, California (Doc. #14782)

8.23 8. Simplify the definition for tributaries

The definition for tributaries should be revised to contain less subjective terms, include 

appropriate exemptions, and be simply defined so as to minimize broad interpretation. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

250

Tributaries have never before been defined in the regulations for Waters of the U.S. In 

the proposed rule, the definition for tributaries is vaguely defined, lacking necessary 

exemptions, and containing many subjective terms. Furthermore, this definition of 

tributary could be interpreted to include stormwater conveyance or treatment facilities 

that previously were not defined as a tributary. By broadening the definition, clean-up 

activities in stormwater conveyance channels could trigger the need for additional 

permits and lengthy certification processes. Because man-made features could be 

considered tributaries under the proposed definition, it should be revised to include 

appropriate exemptions for features that require County maintenance and oversight. 

Features such as BMPs, roadside ditches, and water conveyances should be exempt. 

Additionally, the definition states that the flow in the tributary may be ephemeral, 

intermittent or perennial. These terms are not further defined in the new rule, and can 

have varying definitions. To avoid broad and subjective interpretation, the terms 

ephemeral and intermittent should be removed, as these terms could be applied to any 

area that is wet and carries water during a single rain event. The term perennial is more 

appropriate for the definition of tributaries and in-line with the existing regulatory 

language, which defines a tributary as being relatively permanent.

EXAMPLE: The County maintains and monitors waterways including roadside ditches, 

flood control channels, and drainage conveyances, which are used to safely guide water 

away from homes, businesses, properties and roads. Man-made features such as ditches 

and canals can be considered tributaries under the proposed definition. Therefore, the 

definition needs to be revised to contain appropriate exemptions in order to appropriately 

monitor and maintain these features. In addition, a ditch that carries water once a year 

and ultimately connects to a Traditionally Navigable Water can be considered ephemeral

and, therefore, would be a tributary based on the new definition. The word ephemeral

should be eliminated from the definition because it can be too broadly and subjectively 

applied. (p. 7)

Agency Response: See summary responses for sections 8.1.1 and 8.4. The 

definition of “tributary” in the final rule requires that flow must be of sufficient 

volume, frequency, and duration to create the physical characteristics of bed and 

banks and an ordinary high water mark. As defined, “tributary” can include 

perennial, intermittent or ephemeral streams. This position is rooted in a sciencebased conclusion that such waters have a significant nexus either individually or in 

the aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion. The final rule also excludes many features from 

consideration as waters of the United States, including most ditches that are not 

relocated tributaries or excavated in tributaries and stormwater control features 

created in dry land. See summary responses in Compendium 7 of this RTC, 

“Features and Waters Not Jurisdictional,” for a broad discussion of the final rule’s 

exclusions features.

Southeast Metro Stormwater Authority (Doc. #14935)

8.24 SEMSWA is troubled that the proposed tributary definition will likely expand what is 

considered jurisdictional Waters of the US. Many remote ephemeral drainages that were 
Clean Water Rule Response to Comments – Topic 8: Tributaries

251

not considered Waters of the US, based on an individual determination made by the local 

USACE office, would be brought into the scope of jurisdictional Waters of the US under 

the proposed rule. (p. 1)

Agency Response: See summary response for section 8.1.1. The final rule, like the 

proposed rule, establishes categorical jurisdiction over all waters that meet the 

definition of “tributary” and that are not excluded in paragraph (b). Ephemeral 

streams with sufficient flow to create the physical characteristics of bed and banks 

and an OHWM meet the definition of tributary, and are thus considered waters of 

the United States. The agencies determined that such streams provide important 

functions for downstream waters, and in combination with other protected 

tributaries in a watershed significantly affect the chemical, physical, and biological 

integrity of traditional navigable waters, interstate waters, and the territorial seas. 

However, the final rule expressly indicates in paragraph (b) that ephemeral reaches 

that do not meet the definition of tributary are not waters of the United States. 

Section VII of the Technical Support Document discusses the science supporting the 

agencies’ conclusion.

Arizona Public Service Company (Doc. #15162)

8.25 ...How much flow and at what frequency is sufficient to qualify a water as a tributary? If 

an ephemeral stream only flows to another WOTUS once a year, is this adequate to 

demonstrate connectivity? What if the connection is less frequent—on the order of 

several years, decades, or longer? (p. 10)

Agency Response: See summary response for sections 8.1.1 and 8.4. The definition 

of “tributary” in the final rule requires that flow must be of sufficient volume, 

frequency, and duration to create the physical characteristics of bed and banks and 

an ordinary high water mark. The Agencies believe that grounding the definition of 

“tributary” in the final rule to the above referenced specific physical features will 

help clarify the distinction between covered tributaries and erosional features, and 

simplify implementation of the final rule. Section VII of the Technical Support 

Document further discusses the science supporting the agencies’ conclusion.

Albuquerque Metropolitan Arroyo Flood Control Authority (Doc. #15221)

8.26 3. Rapanos Requires a Case-By-Case Analysis

The conclusion that all MS4 tributaries are jurisdictional per se is counter to the 

principles established in the Rapanos decision. As the Court noted in its decision, for an 

effect to be significant it must be more than speculative or insubstantial. However, MS4 

systems have extremely limited effect on TNWs because they flow only when it rains. 

Nevertheless, the proposed rule concludes that streams—regardless of their size or 

frequency of flow—strongly influence how downstream waters function, whether it be by 

supplying most of the water, transporting sediment or organic matter, providing habitat, 

or changing nutrients. Yet none of these apply to the AMAFCA MS4 system. The Rio 

Grande is impacted by the Albuquerque MS4 only during the strongest events during the 

rainy season, usually consisting of a matter of hours or days of water contribution. The 

stormwater does not affect downstream water function, such as by providing organic 

matter, habitat, or taking up nutrients. Unlike other tributaries, the primary function of the 
Clean Water Rule Response to Comments – Topic 8: Tributaries

252

MS4 system is not to transport sediment downstream, but to capture stormwaters to 

prevent flooding. The stormwater does not provide flow to downstream rivers to support 

navigation. Instead, the primary claim to jurisdiction has been on the ability of the MS4 

system to deposit pollutants in the river.

However, for a significant nexus to exist, there must be more than an insubstantial or 

speculative effect on the chemical, physical, or biological integrity of the river. Without 

evaluating the individual MS4 systems, including the capacity of each to carry pollutants, 

and the multitude of data collected under the NPDES permit regarding water quality at 

the time of conveyance, it is impossible to determine whether a significant nexus does in 

fact exist.

Furthermore, as AMAFCA is aware of the debris and floatable pollutants which enter the 

MS4 systems from various point sources, AMAFCA has implemented water quality 

treatment measures throughout the system. AMAFCA conducts extensive maintenance 

on these facilities throughout the year to remove pollutants and ensure the water quality 

features work as designed. To date, there is no data to support any contention that either 

chemical or floatable pollutants from the MS4 system are impacting the river, especially 

in quantities greater than those authorized under the existing NPDES discharge permit. 

More importantly, the potential to impact chemical integrity is unlike that of other 

tributaries. While most tributaries affect the TNW by trapping chemicals or transporting 

suspended sediments, the waters from the MS4 serve no such function.

Instead, jurisdiction based on the system’s ability to affect the chemical consistency of 

the river would be based merely on the presence of pollutants in the system upstream of 

the installed BMP’s. Concluding that the system affects the chemical integrity of the river 

because of the presence of pollutants upstream of installed BMPs requires speculation as 

to the effectiveness of those BMPs. As Rapanos has made clear that speculation is 

impermissible in asserting jurisdiction, such a conclusion is prohibited. Instead, in order 

to assert jurisdiction, a case-specific evaluation must be made to determine whether the 

AMAFCA MS4 system is actually having an impact on the Rio Grande River. (p. 5-6)

Agency Response: See summary responses for sections 8.1.1 and 8.1.2. The final 

rule eliminates the need to identify a water as relatively-permanent (as was required 

under the Rapanos guidance) or conduct a significant nexus determination for each 

tributary. Instead, the final rule establishes categorical jurisdiction over all waters 

that meet the definition of "tributary" and that are not excluded in paragraph (b). 

Section I of the Technical Support Document further discusses the legal issues 

concerning the final rule, including consistency with the statute and Supreme Court 

decisions. Section VII of the Technical Support Document discusses the science 

supporting the agencies' determination that waters meeting the definition of 

"tributary" have a significant nexus because they significantly affect the chemical, 

physical, and biological integrity of traditional navigable waters, interstate waters, 

and the territorial seas. The agencies further note that the final rule is solely a 

definitional rule, and specific implementation of permitting programs, including the 

CWA NPDES program, are beyond the scope of the rule. See additional responses 

addressing rule’s application to man-made structures and stormwater control 

features.
Clean Water Rule Response to Comments – Topic 8: Tributaries

253

Southern Company (Doc. #14134)

8.27 I. The New Definition of “Tributary” Extends to Waters that Historically Have Not 

Been Regulated and that Have, at Best, an Insubstantial Connection with TNWs

The agencies propose a new definition for “tributary” that is extremely broad. It would 

make all tributaries of TNWs jurisdictional, without regard to a “significant nexus” 

evaluation. This would include all perennial, intermittent, and ephemeral features. That 

is, under the proposal as written, all tributaries would be deemed by rule to have a 

significant nexus to TNWs. In several respects, this aspect of the proposal far exceeds the 

scope of tributaries historically deemed jurisdictional and is not supported by science or 

law.

A. The Definition for Tributary Is Inconsistent with the Agencies’ Goal of Providing 

Greater Clarity and the SAB’s Recommendations

At a minimum, under the proposed rule, tributaries must contribute flow (directly or 

indirectly) to TNWs or impoundments in order to be jurisdictional. Determining whether 

a feature contributes flow, however, will require a case specific assessment—particularly 

where there is no “continuous surface connection.” As a practical matter, this 

determination is likely to look a lot like the agencies’ proposed “significant nexus” 

determination. In this way, the agencies’ proposed new definition for “tributary” is at 

odds with the structure of the rule and the agencies’ goal of providing predictability, 

consistency, and certainty.

Under the proposal’s new definition, the critical inquiry in the context of whether a 

feature is a tributary (and jurisdictional), is whether the feature contributes flow. Yet, the 

proposal is essentially silent on what this means, and the agencies have offered no 

standards for the requisite frequency, duration, magnitude, predictability, and 

consequences of those flow contributions. This was a significant criticism by the SAB 

panelists and only creates more confusion and uncertainty.

The agencies have based their assumption regarding tributaries in large part on the 

purported scientific evidence in the Draft Connectivity Report. Despite the fact that this 

report had not yet been finalized, the agencies concluded in their proposal that the 

scientific consensus supports its decision to assert jurisdiction over all tributaries based 

on their importance and significant nexus to TNWs. See 79 Fed. Reg. at 22201. Yet, as 

noted above, the SAB Connectivity Panel has since criticized the agencies’ basic 

approach to defining significant nexus, including in the context of tributaries. SAB Final 

Report at 3 (“[T]he EPA should recognize that there is a gradient of connectivity.”) The 

SAB made numerous recommended revisions to EPA regarding the agency’s 

Connectivity Report to reflect a gradient approach that recognizes variation in the 

frequency, duration, magnitude, predictability, and consequences of those connections.

To provide greater clarity, the agencies must offer clear, step-by-step guidance for use in 

the field for determining whether a nexus is more than speculative. For example, one of 

the SAB panelists, Dr. Genevieve Ali, offered a methodology that could provide an 

objective nexus score (ranging from 1—30) for any given water based on the frequency, 

magnitude, and duration of the connectivity. We believe this type of approach, with 

sufficient guidance and clarity for field implementation, is potentially promising and 
Clean Water Rule Response to Comments – Topic 8: Tributaries

254

warrants further consideration. This approach could be further developed and proposed 

for public comment in a re-issued proposal or supplemental proposed rule. (p. 30-31)

Agency Response: See summary response for section 8.1.1. Previous definitions of 

“waters of the United States” regulated all tributaries without qualification. 

Compared to the historic scope of the existing rule, the final rule is narrower; 

compared to agency practice in light of guidance issued after SWANCC and 

Rapanos, the final rule is generally broader, but not broader than the existing rule. 

The agencies’ position in regard to tributaries is rooted in a science-based 

conclusion that such waters have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. See also summary responses for section 8.1. The final rule is similar to the 

proposal, but important revisions and clarifications have been made in response to 

public comments. The definition of “tributary” in the final rule requires that flow 

must be of sufficient volume, frequency, and duration to create the physical 

characteristics of bed and banks and an OHWM. The preamble in section IV.F.1 

includes an explanation of bed and banks adapted largely from longstanding 

agencies’ practice, as well as public comments on the proposed rule. The final rule 

adds the Corps’ existing regulatory OHWM definition to EPA’s regulations. Section 

VII of the Technical Support Document discusses the science supporting the 

agencies’ determination that waters meeting the definition of “tributary” have a 

significant nexus. Further, the agencies note that the SAB found the available 

science provides an adequate scientific basis for the key components of the proposed 

rule. Section III(B) of the preamble discusses in detail the Science Report and the 

SAB’s comments on the proposed rule and how they were addressed in the final 

rule. Overall, the agencies conclusions were informed by the Science Report and the 

review and comments of the SAB, but not dictated by them. The rule reflects the 

judgment of the agencies when balancing the science, the statute, the Supreme 

Court opinions, the agencies’ expertise, and the regulatory goals of providing clarity 

to the public while protecting the environment and public health. Section I of the 

Technical Support Document further discusses the legal issues concerning the final 

rule, including consistency with the statute and Supreme Court decisions.

8.28 B. The Agencies Should Not Make Ephemeral Features Categorically Jurisdictional

This is the first time the agencies have asserted blanket jurisdiction over all tributaries as 

per se jurisdictional. Historically, only certain ephemeral features with an OHWM have 

been deemed jurisdictional, following a case specific analysis. See 65 Fed. Reg. 12823 

(2000) and GAO-04-297 Report “Waters and Wetlands: Corps of Engineers Needs to 

Evaluate Its District Office Practices in Determining Jurisdiction. The agencies have 

failed to provide a sufficient rationale for abandoning this longstanding approach. And by 

establishing per se jurisdiction over all tributaries and abandoning case-by-case 

assessments of intermittent and ephemeral features, the agencies are building this 

important proposal on legally and technically unstable ground. This is problematic for 

several reasons.

For one, the blanket assertion of jurisdiction over all tributaries contravenes Justice 

Kennedy’s significant nexus text, which Justice Kennedy applied to tributaries, 

particularly minor tributaries involving insignificant connections to TNWs. “This 
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255

standard presumably provides a rough measure of the volume and regularity of flow. 

Assuming it is subject to reasonably consistent application . . . it may well provide a 

reasonable measure of whether specific minor tributaries bear a sufficient nexus with 

other regulated waters to constitute ‘navigable waters’ under the Act.” Rapanos, 547 U.S. 

at 781–82 (Kennedy, J. concurring). Thus, Justice Kennedy’s significant nexus test does 

not support a broad and unlimited assertion of jurisdiction over all tributaries without 

regard to their connection to downstream waters.

In addition, as a practical matter, ephemeral features flow only in direct response to 

precipitation and only for a brief period. Such features do not always reach perennial 

water and many only reach perennial water during certain substantial storm events. To 

exercise jurisdiction over all such ephemeral features, without establishing whether their 

connectivity is, in fact, “more than speculative or insubstantial,” is unlawful under a 

proper reading of Rapanos.

Also, as noted above, the SAB Connectivity Panel has called for a gradient versus 

categorical approach to define connectivity. If the agencies were to choose to ignore this 

recommendation and retain their categorical approach, as they appear poised to do, they 

should establish bright line tests only where bright lines actually exist. The most basic 

and supportable approach would be to define “categorically jurisdictional” tributaries 

based on the Rapanos plurality and limit the definition of “tributaries” to “those relatively 

permanent, standing or continuously flowing bodies of water.” Id. at 716 (“The phrase 

‘the waters of the United States’ includes only those relatively permanent, standing or 

continuously flowing bodies of water ‘forming geographic features’ that are described in 

ordinary parlance as ‘streams,’ ‘oceans, rivers, [and] lakes,’ Webster’s New International 

Dictionary 2882 (2d ed.), and does not include channels through which water flows 

intermittently or ephemerally, or channels that periodically provide drainage for 

rainfall...”). (p. 32-33)

Agency Response: The final rule, like the proposed rule, establishes categorical 

jurisdiction over all waters that meet the definition of “tributary” and that are not 

excluded in paragraph (b). Ephemeral streams with sufficient flow to create the 

physical characteristics of bed and banks and an OHWM meet the definition of 

tributary, and are thus considered waters of the United States. The agencies 

determined that such streams provide important functions for downstream waters, 

and in combination with other protected tributaries in a watershed significantly 

affect the chemical, physical, and biological integrity of traditional navigable waters, 

interstate waters, and the territorial seas. However, the final rule expressly 

indicates in paragraph (b) that ephemeral reaches that do not meet the definition of 

tributary are not waters of the United States. Section VII of the Technical Support 

Document discusses the science supporting the agencies’ conclusion. See also 

responses addressing significance of “breaks” in bed and bank and OHWM and 

discussion in TSD and elsewhere regarding consistency of rule with applicable 

Supreme Court cases.

8.29 C. The Agencies Must Revisit Preamble Statements That Confuse “Tributary” and 

“Adjacency” Concepts
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The preamble to the proposed rule indicates that tributaries “must drain, or be part of a 

network of tributaries that drain” into TNWs or impoundments. 79 Fed. Reg. at 22202 

(emphasis added). If that is the case, then a feature could be a categorically jurisdictional 

tributary, even if it does not itself drain to a TNW, as long as it is part of a larger network 

of features that do drain to a TNW or impoundment. This is inconsistent with the basic 

requirement that tributaries must “contribute flow” and it blurs the line between a 

tributary analysis and an adjacency analysis under the agencies’ proposed rule. Equally 

troubling is the fact that the concept of “be[ing] part of a network of tributaries” is left 

entirely undefined and open to competing interpretations. Thus, here again, we have a 

component of the proposal that invites confusion.

To the extent that the agencies’ reference to “a network of tributaries” indicates that they 

are infusing their proposed “aggregation” analysis into the tributary analysis, we find this 

to be equally troubling. We firmly believe that aggregation should not be part of the 

proposed rule’s case-by-case “significant nexus” analysis. It most certainly should not be 

included within the “categorically jurisdictional” features of the proposed rule (i.e., 

tributaries and adjacent waters). (p. 33)

Agency Response: See summaries for sections 8.1 and 8.2. The final rule reflects 

public comments on the proposed rule in several important ways. In particular, the 

final rule emphasizes the importance of flow. The rule definition of “tributary” 

requires that flow much be of sufficient volume, frequency, and durations to create 

physical characteristics of bed and banks and an OHWM. As a result, wetlands, 

lakes, ponds, and other features lacking a bed and banks and/or OHWM are no 

longer defined as tributaries in the Final Rule, however, they still may be considered 

jurisdictional waters of the U.S. either as adjacent waters or similarly situated 

waters with a significant nexus to (a)(1) through (3) waters. See TSD section 8 for 

adjacency, section 7 for tributaries, and section 2.B for treatment of similarly 

situated waters. 

8.30 E. The Agencies’ Proposal Fails to Consider Practical Problems Associated with an 

Expansive Definition of “Tributary”

The agencies approach to defining “tributary” has, at best, blurred well-established 

jurisdictional lines and, at worst, extended them far beyond longstanding legal 

boundaries. We are equally concerned about a number of practical difficulties this 

approach would impose.

For one, under the proposal, a tributary would not lose its status as a tributary (i.e., cannot 

be de-federalized) by man-made can be WOUS under current practice. The final rule 

does not change this practice. The breaks or activities (e.g., can be one or more 

constructed breaks (such as bridges, culverts, pipes, or dams), or even where a tributary 

may naturally disappear and flow underground.235 79 Fed. Reg. 22201–02. Such an 

 

235 According to the preamble, “A water that otherwise qualifies as a tributary under the proposed definition does not 

lose its status as a tributary if, for any length, there are one or more man-made breaks (such as bridges, culverts, 

pipes, or dams), or one or more natural breaks (such as debris piles, boulder fields, or a stream segment that flows 

underground) so long as a bed and banks and an ordinary high water mark can be identified upstream of the break.” 

79 Fed. Reg. at 22202.
Clean Water Rule Response to Comments – Topic 8: Tributaries

257

approach could be extremely problematic, especially since the agencies have proposed no 

geographic or temporal limits to its application. At a minimum, the agencies must 

establish geographic and temporal limits on the hydrologic breaks that would 

categorically not disrupt CWA jurisdiction. (p. 35)

Agency Response: See summary responses for sections 8.1.1 and 8.3. Under the 

final rule, a water that otherwise qualifies as a tributary under the rule's definition 

does not lose its status as a tributary if, for any length, there are one or more manmade breaks (such as bridges, culverts, pipes, or dams), or one or more natural 

breaks (such as wetlands at the head of or along the run of a stream, debris piles, 

boulder fields, or a stream that flows underground) so long as a bed and banks and 

an ordinary high water mark can be identified upstream of the break. These physical 

indicators demonstrate the water contributes sufficient flow to have a significant 

impact on downstream waters. Absence of these indicators generally represent the 

upper limit of the tributary. Section IV of the Technical Support Document 

discusses further the science that supports the agencies' conclusion. Further, the 

agencies will continue existing practice of making case by case determinations of the 

length of break in OHMD that does not sever the connection to downstream waters.

CPS Energy (Doc. #14566)

8.31 In making all "tributaries" categorically jurisdictional, the Agencies are attempting to 

apply a bright line rule to very complex hydro-ecological systems and making a broad 

general assumption that all dry, ephemeral creeks found in arid and semi-arid areas, or 

seasonal seeps and springs, have connectivity or significant nexus to traditional 

jurisdictional waters. The Rapanos plurality opinion states that jurisdictional WOUS are 

"only those permanent, standing or continuously flowing bodies of water ... that are 

described in ordinary parlance as streams, oceans, rivers, (and) lakes and do not include 

channels through which water flows intermittently or ephemerally, or channels that 

periodically provide drainage for rainfall." CPS Energy believes that the Agencies 

should retain the case-by-case jurisdictional determination for significant nexus that has 

been practiced by the Corp since Rapanos for water bodies that do not have a physical 

manifestation of connectivity to downstream traditional water bodies. (p. 3)

Agency Response: See summary response for section 8.1. The agencies disagree 

that tributaries should be evaluated on a case-by-case basis. Section VII of the 

Technical Support Document discusses the science supporting the agencies’ 

determination that waters meeting the definition of “tributary” have a significant 

nexus because they significantly affect the chemical, physical, and biological 

integrity of traditional navigable waters, interstate waters, and the territorial seas. 

Section I of the Technical Support Document describes the legal basis of the final 

rule, including its consistency with the statute and case law.

Colorado Water Congress Federal Affairs Committee (Doc. #14569)

8.32 Despite the proposal’s stated objective to add clarity to the regulatory process, the 

proposal in fact creates great confusion and uncertainty. Some of the unanswered 

questions have been alluded to above, e.g., what will be the effect of the proposal on the 

construction and operation of stormwater control facilities or the repair and replacement 
Clean Water Rule Response to Comments – Topic 8: Tributaries

258

of ditches. Other issues that must be addressed, through clarification and in the context of 

an ongoing dialogue amongst stakeholders, include:

...

 Is it accurate to state that “all” ephemeral or intermittent streams will now be 

considered jurisdictional (should be treated as case-by-case “other waters”);

 Is it accurate to state that waters adjacent to tributaries, including non-navigable 

tributaries, regardless of how remote or insubstantial the connection, are now 

jurisdictional (should be case-by-case determination);

... (p. 6, 7)

Agency Response: See summary response for section 8.1.1 and 8.2. The final rule, 

like the proposed rule, establishes categorical jurisdiction over all waters that meet 

the definition of “tributary” and that are not excluded in paragraph (b). Ephemeral 

and intermittent streams with sufficient flow to create the physical characteristics of 

bed and banks and an OHWM meet the definition of tributary, and are thus 

considered waters of the United States. The agencies determined that such streams 

provide important functions for downstream waters, and in combination with other 

protected tributaries in a watershed significantly affect the chemical, physical, and 

biological integrity of traditional navigable waters, interstate waters, and the 

territorial seas. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion with regard to tributaries. Section VIII of the 

TSD addresses adjacency and section II.B addresses analysis of similarly situated 

waters. 

Southern Nevada Water Authority (Doc. #14580)

8.33 Under the Proposed Rule, a tributary with ephemeral flow that is "part of a network of 

tributaries that drain into a[traditional WOTUS]" (79 FR 22202) would automatically be 

a WOTUS. In the desert southwest, dry washes may be interconnected over a broad 

region. However, they very rarely carry any water, and only have flowing water when 

there is an intense, typically highly localized, rain event. Unless ephemeral washes are 

located near a stream with perennial water flow, water carried through most ) or one or 

more natural ephemeral washes quickly percolates back into the ground before reaching 

any traditional WOTUS. Thus, for most of the desert southwest, water conveyed through 

ephemeral washes does not directly, or indirectly through another water, flow into a 

traditional WOTUS. Thus, these ephemeral flows would not contribute to the chemical, 

physical, and biological conditions of downstream traditional WOTUS. SNWA 

recommends ephemeral flow be removed from the definition of tributary, and that the 

Proposed Rule clarify an ephemeral drainage, or portion thereof, would be jurisdictional 

only if it conveys water that actually reaches and flows into a traditional WOTUS. (p. 2)

Agency Response: See summary response for sections 8.1.1 and 8.4. The definition 

of “tributary” in the final rule requires that flow must be of sufficient volume, 

frequency, and duration to create the physical characteristics of bed and banks and 

an ordinary high water mark. The Agencies believe that grounding the definition of 

“tributary” in the final rule to the above referenced specific physical features will 
Clean Water Rule Response to Comments – Topic 8: Tributaries

259

help clarify the distinction between covered tributaries and erosional features, and 

simplify implementation of the final rule. Section VII of the Technical Support 

Document further discusses the science supporting the agencies’ conclusion.

Santa Clara Valley Water District, California (Doc. #14776)

8.34 The definition of tributaries should make clear that they contribute flow during dry 

weather. During wet weather, water flows in small channels and rivulets across what is 

indisputably uplands. If channelized wet-weather flow plus overland flow of runoff from 

precipitation is enough to become waters of the United States, then much of the 

landscape would be waters. After all, during even a moderate storm, water is flowing 

across virtually the entire landscape, and, because sheet flow is rare, nearly all of that 

water is flowing in some sort of channel. The first sentence of paragraph (c)(5) of the 

proposed regulation should be revised to clarify that the term tributary does not apply to 

areas that channel water during wet weather only. (p. 3-4)

Agency Response: See summary response for 8.1.1.” The definition of “tributary” 

in the final rule requires that flow must be of sufficient volume, frequency, and 

duration to create the physical characteristics of bed and banks and an ordinary 

high water mark. These physical indicators demonstrate there is sufficient volume, 

frequency and duration of flow to significantly affect downstream waters. If a water 

lacks sufficient flow to create such characteristics, it is not considered “tributary” 

under this rule. By grounding the definition of “tributary” in the final rule to the 

above referenced specific physical features, the agencies believe that confusion 

regarding whether a feature is a “tributary” or a non-jurisdictional “erosional 

feature” will be minimal. Section VII of the Technical Support Document further 

discusses the science supporting the agencies’ conclusion that all waters that meet 

the definition of “tributary” and that are not excluded in paragraph (b), have a 

significant nexus either individually or in the aggregate with traditional navigable 

waters, interstate waters, and the territorial seas. See also summary response under 

section 8.4: Distinction between ephemeral water and a non-jurisdictional gulley, rill 

or non-wetland swale.

ERO Resources Corporation (Doc. #14914)

8.35 The proposed rule takes a "one size fits all" approach to a very wide range of drainage 

types (except for the narrow range of drainages that qualify as exempt). Assuming that all 

tributaries, including ephemeral and intermittent drainages, are jurisdictional by rule is an 

oversimplification. While this approach may be expedient from the agencies' perspective, 

it is not supported by the literature (discussed below), intuitively does not make sense, is 

contrary to the Rapanos opinions, and does not provide the regulated community an 

opportunity to demonstrate that an ephemeral or intermittent drainage lacks a significant 

nexus to a jurisdictional water. The proposed presumption that all waters that meet the 

definition of tributary are jurisdictional by rule is only accurate over a portion of the 

spectrum of potential tributary types. The presumption is applicable at the wet end of the 

spectrum (e.g., rivers and perennial streams) and becomes increasingly less applicable as 

one moves toward the drier end of the tributary spectrum, particularly with smaller 
Clean Water Rule Response to Comments – Topic 8: Tributaries

260

drainages in the arid West. At the drier portion of the tributary spectrum, the presumption 

of jurisdictional by rule is no longer accurate and becomes arbitrary. (p. 11-12)

Agency Response: The agencies disagree that tributaries cannot be categorically 

considered waters of the United States. See summary response for section 8.1.1. The 

agencies’ position in regard to tributaries is rooted in a science-based conclusion 

that such waters have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

conclusion. Further, Section I of the Technical Support Document discusses the 

legal issues concerning the final rule, including consistency with the statute and 

Supreme Court decisions.

8.36 The proposed rule does not distinguish between ephemeral and intermittent drainages, 

which further underscores how the rule considers all tributaries to be the same and 

inappropriately biases dry intermittent and ephemeral drainages toward jurisdiction as 

"jurisdictional by rule." These differences are accentuated in the arid West where 

precipitation is limited and seasonal, and year-to-year ground water levels can vary 

considerably. It is also clear that the hydrology of ephemeral and intermittent drainages is 

very different from rivers and perennial streams. The Corps currently recognizes these 

differences in the Nationwide Permit (NWP) regulations. For example, for NWPs 29 

Residential Development, 39 Commercial and Institutional Developments, and 42 

Recreational Facilities, the Corps distinguishes between the impact threshold for loss of 

streambed for perennial streams and ephemeral or intermittent streams. For ephemeral or 

intermittent streambeds, the district engineer can waive the 300-linear-foot impact 

threshold. If the Corps believed that the resources of all tributaries were equal, the NWPspecific impact thresholds would not distinguish between perennial streams and 

ephemeral or intermittent streams. (p. 13)

Agency Response: See summary responses for sections 8.1.1 and 8.4. The 

definition of “tributary” in the final rule requires that flow must be of sufficient 

volume, frequency, and duration to create the physical characteristics of bed and 

banks and an ordinary high water mark. As defined, “tributary” can include 

perennial, intermittent or ephemeral streams. This position is rooted in a sciencebased conclusion that such waters have a significant nexus either individually or in 

the aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion. 

Utility Water Act Group (Doc. #15016)

8.37 The Proposed Rule does not provide for any examination of the frequency or volume or 

duration of flow. A tributary connection does not have to be “continuous” for a 

waterbody to be a jurisdictional tributary. Even if there are one or more man-made breaks 

(e.g., bridges, culverts, pipes, or dams) or one or more natural breaks (e.g.,such as 

wetlands along the run of a stream, debris piles, boulder fields, or a stream that flows 

underground), the tributary retains its jurisdictional status so ) as long as there is OHWM 

above and below the break. The extent of jurisdiction of tributaries are limited to those 

that have a bed, and bank, and ordinary high water mark can be identified upstream of the 
Clean Water Rule Response to Comments – Topic 8: Tributaries

261

break. Thus, the presence of only a few physical features has become the legal test for a 

jurisdictional “tributary”; no consideration of chemical and biological attributes – either 

within the water being evaluated or in a downstream TNW – is required. The Proposed 

Rule also, for the first time, specifically defines ditches as jurisdictional tributaries under 

all CWA programs. Other man-made conveyances that drain or connect would also likely 

qualify as tributaries. Under the Proposed Rule, the “tributary” definition therefore would 

sweep in many features that are remote and carry only minor water volumes. It also 

would expressly sweep in man-made water features, unless specifically excluded. (p. 48-

49) and OHWM. Waters which do not contribute flow to an (a)1-(a)3 WOUS are also not 

defined as tributaries.

Agency Response: See summary responses for sections 8.1.1 and 8.4. The 

definition of “tributary” in the final rule requires that flow must be of sufficient 

volume, frequency, and duration to create the physical characteristics of bed and 

banks and an ordinary high water mark. The agencies have determined that 

streams with these physical characteristics provide important functions for 

downstream waters, and in combination with other protected tributaries in a 

watershed significantly affect the chemical, physical, and biological integrity of 

traditional navigable waters, interstate waters, and the territorial seas. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

conclusion. See also discussion in 8.3 regarding relevance of of breaks on OHWM.

8.38 The Agencies have proposed a determination that a tributary can have a significant nexus 

when the waterbody itself is considered with all other tributaries within a watershed: 

[T]he agencies conclude that tributaries, including headwaters, intermittent, and 

ephemeral streams, and especially when all tributaries in a watershed are 

considered in combination, have a significant nexus . . . .

79 Fed. Reg. at 22,206 col. 1.

UWAG believes that this determination (referred to as “tributary aggregation”) is highly 

speculative from a scientific standpoint, for the following reasons:

 The structure and function of tributaries within a single watershed can vary 

markedly, based on the physicochemical and biological factors that shape the 

structure and function. Thorp et al. (2006) state:

Poole (2002) proposed that: (a) rivers are composed of patchy discontinua where 

the community responds to local features of the fluvial landscape; and (b) a 

community within a stream segment is not necessarily more similar structurally 

and functionally to communities in adjacent segments than it is to groups located 

farther upstream or downstream.

Id. at 125 (emphasis added).

 Regulatory agencies, when determining whether waterbody segments are 

attaining applicable water quality standards, assess individual streams. If one 

stream is not attaining a particular standard or criterion, no assumption is made 

whether adjacent streams display the same condition.
Clean Water Rule Response to Comments – Topic 8: Tributaries

262

 Refuting the “tributary aggregation” assumption is virtually impossible because 

actually evaluating the hydrological connectivity of all streams in a watershed 

would be overly burdensome. (p. 129-130)

Agency Response: The agencies disagree with the comment that aggregating 

tributaries within a watershed is highly speculative from a scientific standpoint. One 

of the main conclusions of the Science Report is that the incremental contributions 

of individual streams and wetlands are cumulative across entire watersheds, and 

their effects on downstream waters should be evaluated within the context of other 

streams and wetlands in that watershed. See preamble discussion in section III(B)In 

their review of the scientific and technical adequacy of the rule, the SAB panel 

members “generally agreed that aggregating ‘similarly situated’ waters is 

scientifically justified, given that the combined effects of these waters on 

downstream waters are often only measurable in aggregate.” See also summary 

responses for Compendium 4, in particular 4.3.1. “Proposed rule method of 

similarly situated in the region.” Lastly, the agencies’ experience evaluating 

similarly situated tributaries for a significant nexus under the 2008 Guidance has 

informed our understanding of streams and while resource intensive, was not overly 

burdensome. 

Colorado River Water Conservation District, Colorado (Doc. #15070)

8.39 The proposed definition of tributary includes ephemeral and intermittent drainages have a 

bed, banks, and a high water mark. Currently, there is no automatic presumption that 

ephemeral and intermittent drainages are jurisdictional; rather, their jurisdictional status 

is determined on a case-by-case basis. Considering ephemeral and intermittent drainages 

jurisdictional by rule could substantially expand Clean Water Act jurisdiction. This is 

particularly true in the arid West where substantial portions of the landscape are 

comprised of ephemeral and intermittent drainages that are dry for most months of the 

year, and sometimes for years at a time. The inclusion of intermittent and ephemeral 

tributaries as jurisdictional by rule would deprive a potentially regulated entity from 

asserting that such a tributary has no significant nexus to a traditionally navigable water, 

and therefore not jurisdictional. (p. 2)

Agency Response: See summary response for section 8.1.1 and 8.2. The final rule, 

like the proposed rule, establishes categorical jurisdiction over all waters that meet 

the definition of “tributary” and that are not excluded in paragraph (b). Ephemeral 

and intermittent streams with sufficient flow to create the physical characteristics of 

bed and banks and an OHWM meet the definition of tributary, and are thus 

considered waters of the United States. The agencies determined that such streams 

provide important functions for downstream waters, and in combination with other 

protected tributaries in a watershed significantly affect the chemical, physical, and 

biological integrity of traditional navigable waters, interstate waters, and the 

territorial seas. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion.
Clean Water Rule Response to Comments – Topic 8: Tributaries

263

Illinois Fertilizer & Chemical Association (Doc. #15129)

8.40 Ephemeral, intermittent and less than perennial flow waters must be removed from the 

definition of tributary. The U.S. Supreme Court has stated at least seasonal flow is 

necessary for water to qualify as a “water of the U.S.” (p. 1)

Agency Response: See summary response for section 8.1.1. Also, Section I of the 

Technical Support Document further discusses the legal issues concerning the final 

rule, including consistency with the statute and Supreme Court decisions.

Idaho Power Company (Doc. #15501)

8.41 The Agencies should revise their jurisdictional-by-rule proposal to clarify that 

jurisdictional "tributaries" are limited to waters that contribute direct flow to a traditional 

navigable water via a continuous surface connection. (p. 7)

Agency Response: See summary response for section 8.1.1. The definition of 

“tributary” in the final rule retains the phrase “contributes flow, either directly or 

through another water.” This reflects scientific literature about the connectivity 

among waters discussed in the summary response of this section, the Technical 

Support Document, and the Science Report. The final rule does not require that the 

flow be contributed either directly or through waters that are themselves 

jurisdictional. Water contributed through non-jurisdictional features can have the 

same impact on the integrity of downstream waters as water contributed through 

jurisdictional waters. 

Lower Colorado River Authority (Doc. #16332)

8.42 1. The Agencies Should Adopt the Rapanos Plurality’s Approach to Regulating 

Tributaries, or a Similar Approach.

...The WWG objects to the Agencies’ proposal to categorically regulate all “tributaries,” 

a term defined to include intermittent and ephemeral streams and most ditches. As further 

explained below, the Agencies’ proposal is inconsistent with the plain language of the 

CWA, the Supreme Court’s interpretations of the Act, and the evidence before the 

Agencies.

Rather than automatically regulating most water bodies with a bed and a bank, the

Agencies should adopt the approach described in Justice Scalia’s plurality opinion in 

Rapanos. Regardless of whether or not the plurality opinion represents the holding of 

Rapanos, the plurality opinion is consistent with the Supreme Court’s historic treatment 

of tributaries. As noted above, Rapanos and Riverside Bayview concerned the unique 

question of whether wetlands that were “inseparably bound up” with adjacent water 

bodies were jurisdictional. Their holdings did not address non-wetland water bodies such 

as ponds, natural streams, and manmade ditches. SWANCC, by contrast, addressed the 

question of whether an isolated pond was jurisdictional. The Court’s clear answer was 

that such ponds were not jurisdictional because the CWA was not intended to regulate 

“nonnavigable, isolated, intrastate waters.”

Consistent with SWANCC’s limited view of CWA jurisdiction over non-wetland water 

bodies, the plurality opinion in Rapanos limited jurisdiction to “those relatively 
Clean Water Rule Response to Comments – Topic 8: Tributaries

264

permanent, standing or continuously flowing bodies of water ‘forming geographic 

features’ that are described in ordinary parlance as ‘streams,’ ‘oceans, rivers, [and] 

lakes.’” The Rapanos plurality also held that CWA jurisdiction does not include channels 

through which water flows intermittently or ephemerally, or channels that periodically 

provide drainage for rainfall. The plurality opinion further indicated that the Agencies’ 

attempt to regulate manmade water bodies as tributaries is not supported by the CWA:

In applying the definition to “ephemeral streams,” “wet meadows,” storm sewers 

and culverts, “directional sheet flow during storm events,” drain tiles, man-made 

drainage ditches, and dry arroyos in the middle of the desert, the [Army] Corps 

has stretched the term “waters of the United States” beyond parody. The plain 

language of the statute simply does not authorize this “Land Is Waters” approach 

to federal jurisdiction.236

The Agencies should revise the Proposed Rule to define jurisdiction over tributaries 

consistent with the Rapanos plurality. Under the plurality’s approach, the Agencies 

would define a tributary as a water that contributes direct flow to a traditional navigable 

water via a continuous surface connection. The plurality’s approach is consistent with the 

plain language of the CWA and its policy to preserve States’ authority over land and 

water use. It is also consistent with SWANCC. The plurality opinion provides a clear, 

defensible basis for the Agencies to draw bright lines including certain types of water 

bodies within CWA jurisdiction and excluding other types of water bodies such as 

intermittent and ephemeral streams.

In the alternative, if the Agencies insist on applying the “significant nexus” test in 

evaluating jurisdiction over tributaries, that test should be applied only to tributaries that 

are not covered by the Rapanos plurality—that is, tributaries that are not “relatively 

permanent, standing or continuously flowing bodies of water ‘forming geographic 

features.’”237 Under this alternative approach, the Agencies could categorically regulate 

these types of non-permanent tributaries while evaluating jurisdiction over other 

tributaries (such as intermittent streams) using the “significant nexus” test. Ephemeral 

streams, however, should not be treated as jurisdictional under any circumstance. No 

reasonable reading of Supreme Court precedent supports the regulation of such clearly 

non-navigable water bodies. (p. 13-14)

Agency Response: See summary response for section 8.1.1. Also, Section I of the 

Technical Support Document further discusses the legal issues concerning the final 

rule, including consistency with the statute and Supreme Court decisions.

8.43 In determining whether a water body is a jurisdictional tributary, the Agencies should 

consider not only the presence of these features but also factors such as the frequency, 

duration, and volume of flow. As discussed above, the Agencies must consider such 

factors to maintain consistency with Justice Kennedy’s concurring opinion in Rapanos

and to give meaning to the word “navigable” in the CWA.

 

236 Rapanos, 547 U.S. at 734.

237 Id. at 739.
Clean Water Rule Response to Comments – Topic 8: Tributaries

265

The jurisdictional status of water bodies will be particularly difficult to determine for 

streams that contribute no direct flow to navigable waters, but may contribute flow 

“indirectly,” through other waters. The Agencies fail to clarify how such an indirect 

contribution may be identified, and fail to specify whether such a contribution must be 

made via a surface water connection or rather, in the Agencies’ view, may be made via 

groundwater. To the extent that the Agencies intend to establish indirect connections via 

groundwater, the WWG objects to such an interpretation, which is unsupported by the 

CWA or any of the Supreme Court’s decisions. (p. 16)

Agency Response: See summary responses for sections 8.1.1 and 8.4. The 

definition of “tributary” in the final rule requires that flow must be of sufficient 

volume, frequency, and duration to create the physical characteristics of bed and 

banks and an ordinary high water mark. This position is rooted in a science-based 

conclusion that such waters have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion. The final rule also retains the phrase 

“contributes flow, either directly or through another water.” This reflects scientific 

literature about the connectivity among waters discussed in the summary response 

of this section, the Technical Support Document, and the Science Report. The final 

rule does not require that the flow be contributed either directly or through waters 

that are themselves jurisdictional. Water contributed through non-jurisdictional 

features can have the same impact on the integrity of downstream waters as water 

contributed through jurisdictional waters. 

Basin Electronic Power Cooperative (Doc. #16447)

8.44 The Agencies are attempting to assert jurisdiction by the using "tributaries" that directly 

or indirectly contribute flow to a navigable water. The Agencies fail to provide 

consideration of the frequency, duration, or amount of flow the tributary provides or the 

tributary's proximity to the navigable water. Definitions must be based on clear, objective 

standards that can be easily understood and consistently applied in the field. (p. 3)

Agency Response: See summary responses for sections 8.1.1 and 8.4. The 

definition of “tributary” in the final rule requires that flow must be of sufficient 

volume, frequency, and duration to create the physical characteristics of bed and 

banks and an ordinary high water mark. This position is rooted in a science-based 

conclusion that such waters have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion.

Cloud Peak Energy (Doc. #18010)

8.45 The proposed definition of "tributary" is very troubling and has the potential to greatly 

expand the scope of the waters regulated as tributaries on mines in Wyoming. The rule 

categorically determines that tributaries regardless of size or significance, that have a 
Clean Water Rule Response to Comments – Topic 8: Tributaries

266

significant nexus to traditional navigable waters (TNW), interstate waters and the 

territorial seas, and will therefore be jurisdictional.238 "Thus any water that meets the 

broad definition of "tributary" will be a jurisdictional WOTUS. Further any water or 

wetland adjacent to tributaries will also be jurisdictional.

This expansive categorical determination is not supported by science. The Science 

Advisory Board (SAB) stated in their review of the Connectivity Report that it is not 

appropriate to treat connectivity as a binary property (connected versus not connected). 

Further the SAB recommended "that the interpretation of connectivity be revised to 

reflect a gradient approach that recognizes variation in the frequency, duration, 

magnitude, predictability and consequences of connections."239 As pointed out in the GEI 

report provided in the WAC comments, "all tributaries ... exist on a gradient of 

connectivity, and the science has not identified the point on the gradient (i.e., the strength 

of connectivity) where the significant nexus falls." Additionally this connectivity report, 

on which the EPA is relying on to support their proposed definition of "tributary", has 

failed to go through the process of peer review for finalization. In sum, the agencies have 

failed to establish any scientific basis for including all tributaries within the definition of 

WOTUS. (p. 2)

Agency Response: The agencies disagree that tributaries cannot be categorically 

considered waters of the United States. Further, the Science Advisory Board 

expressed support for the rule’s inclusion of tributaries as categorical waters of the 

United States. See summary response for section 8.1.1. Section VII of the Technical 

Support Document discusses the science supporting the agencies' determination that 

waters meeting the definition of "tributary" have a significant nexus because they 

significantly affect the chemical, physical, and biological integrity of traditional 

navigable waters, interstate waters, and the territorial seas. Lastly the connectivity 

report did complete multiple levels of peer review, see TSD section II.A. 

Xcel Energy (Doc. #18023)

8.46 Xcel Energy recommends the agencies identify a new standard for tributaries that is 

based on scientific evidence and covers only tributaries that have the requisite 

relationship to jurisdictional waters, such as where there is a relatively permanent or 

ordinary presence of water... (p. 7)

Agency Response: See summary responses for sections 8.1.1 and 8.1.2. The final 

rule eliminates the need to identify a water as relatively-permanent, or conduct a 

significant nexus determination for each tributary. Instead, the final rule establishes 

categorical jurisdiction over all waters that meet the definition of "tributary" and 

that are not excluded in paragraph (b). Section I of the Technical Support 

Document further discusses the legal issues concerning the final rule, including 

consistency with the statute and Supreme Court decisions. Section VII of the 

Technical Support Document discusses the science supporting the agencies' 

 

238 79 Fed. Reg. at 22,201.

239 SAB Panel Review of Connectivity Report, Exhibit 5 at 3. The gradient approach to connectivity is 

recommended at least 28 times in the SAB review of the Connectivity Report.
Clean Water Rule Response to Comments – Topic 8: Tributaries

267

determination that waters meeting the definition of "tributary" have a significant 

nexus because they significantly affect the chemical, physical, and biological 

integrity of traditional navigable waters, interstate waters, and the territorial seas

and biological integrity of traditional navigable waters, interstate waters, and the 

territorial seas.

Ducks Unlimited (Doc. #11014)

8.47 We agree with the agencies' statement that the literature "clearly demonstrates that 

streams, "regardless of their size or how frequently they flow, strongly influence how 

downstream waters function." The preamble provides an excellent summary of the 

relationship between the synthesis of the science related to tributaries and the purposes of 

the Act... Therefore, based on the science thoroughly reviewed in the draft Connectivity 

Report and in Appendix A, Scientific Evidence (henceforth, "Appendix"), the finding that 

all tributaries, as a class, have a significant nexus with and impact upon the physical, 

chemical and biological integrity of downstream (a)(l) through (a)(3) waters and are 

therefore jurisdictional by rule, is scientifically appropriate and sound. (p. 13)

Agency Response: The agencies agree with the commenter that tributaries 

provide important functions that support the chemical, physical and biological 

integrity of downstream waters. Any water meeting the definition of "tributary," as 

stated in the final rule, has a significant nexus to traditional navigable waters, 

interstate waters, or the territorial seas, and is therefore considered a “waters of the 

United States.” In making this determination, the agencies relied not only on the 

science, but also on their technical expertise and practical experience in 

implementing the CWA during a period of over 40 years. In addition, the agencies 

were guided, in part, by the compelling need for clearer, more consistent and easily 

implementable standards to govern administration of the CWA, including brighter 

lines where feasible and appropriate.”

8.48 ... We agree that the literature "clearly demonstrates that streams, regardless of their size 

or how frequently they flow, strongly influence how downstream waters function." 

Therefore, the finding that all tributaries, as a class, have a significant nexus with and 

impact upon the physical, chemical and biological integrity of downstream (a)(1) through 

(a)(3) waters and therefore should be jurisdictional by rule, is scientifically appropriate 

and sound... (p. 75)

Agency Response: See response immediately above.

Choose Clean Water Coalition et al. (Doc. #11773.1)

8.49 The Proposed Rule Will Protect Drinking Water in the Chesapeake Bay Watershed. 

Approximately 11 million people - nearly two out of three - in the Chesapeake Bay 

watershed get their drinking water directly from the rivers and streams flowing into 

Chesapeake Bay.240 All of these river and streams are dependent on high quality water 

 

240 U.S. Environmental Protection Agency, "National Hydrography Dataset Plus; Federal Safe Drinking Water

Information System 4th Quarter 2006 Data."
Clean Water Rule Response to Comments – Topic 8: Tributaries

268

from intermittent and ephemeral streams in their headwater areas - waters that would be 

protected by this proposed rule,

Delaware: In Delaware, over 280,000 people receive their drinking water from public 

systems that rely at least in part on intermittent, ephemeral or headwater streams.

Maryland: Nearly four million Marylanders receive their drinking water from public 

systems that rely at least in part on intermittent, ephemeral or headwater streams.

New York: Across New York, over eleven million people receive their drinking water 

from public systems that rely at least in part on intermittent, ephemeral or headwater 

streams.

Pennsylvania: More than 8 million Pennsylvanians receive their drinking water from 

public systems that rely at least in part on intermittent, ephemeral or headwater streams.

Virginia: Across Virginia, over 2.3 million people receive their drinking water from 

public systems that rely at least in part on intermittent, ephemeral or headwater streams.

West Virginia: More than one million West Virginians receive their drinking water from 

public systems that rely at least in part on intermittent, ephemeral or headwater streams. 

The Elk River disaster in Charleston, West Virginia - which impacted the drinking water 

source of upwards of 300,000 people - underscored the importance of protecting drinking 

water sources for all Americans. (p. 2)

Agency Response: The agencies agree with the commenter that ephemeral and 

intermittent streams can be valuable sources of drinking water in the Chesapeake 

Bay Watershed. The final rule, like the proposed rule, establishes categorical 

jurisdiction over all waters (including intermittent, ephemeral and headwater 

streams) which meet the definition of “tributary” and are not excluded in 

paragraph (b). In making this determination, the agencies relied not only on the 

science, but also on their technical expertise and practical experience in 

implementing the CWA during a period of over 40 years. In addition, the agencies 

were guided, in part, by the compelling need for clearer, more consistent and easily 

implementable standards to govern administration of the CWA, including brighter 

lines where feasible and appropriate.

8.50 The Proposed Rule Will Protect Sensitive Waters in the Chesapeake Bay 

Watershed.

One of the most important aspects of the proposed rule is its protection of intermittent 

and ephemeral streams. Protection of these sensitive headwaters is critical to 

safeguarding water quality and wildlife throughout the Chesapeake Bay watershed. 

The Chesapeake Bay watershed has 147,149 miles of rivers and streams.241 Thirty eight 

percent, or 56,689 of those miles, are intermittent or ephemeral streams that would be 

protected by the proposed rule.242 In Maryland, sixteen percent or 3,874 of the state's 

 

241 United States Geological Service, available at: http://nhd.usgs.gov/ ftp://nhdftp.usgs.gov/DataSets/Staged/

SubRegions/

242 United States Geological Service, available at: http://nhd.usgs.gov/. ftp://nhdftp.usgs.gov/DataSets/Staged/

SubRegions/
Clean Water Rule Response to Comments – Topic 8: Tributaries

269

23,671 steam miles are intermittent or ephemeral. Approximately 32,000 miles - or 65 

percent - of Virginia's streams could be considered headwater tributary streams.243 The 

Susquehanna River watershed, which runs through New York, Pennsylvania, and a small 

part of Maryland, boasts 45,582 miles of streams and rivers. Twenty six percent - or 

12,878 miles - of those streams are intermittent and would be protected under the 

proposed rule. (p. 3)

Agency Response: The final rule, like the proposed rule, establishes categorical 

jurisdiction over all waters (including intermittent, ephemeral and headwater 

streams) which meet the definition of “tributary” and are not excluded in 

paragraph (b). In making this determination, the agencies relied not only on the 

science, but also on their technical expertise and practical experience in 

implementing the CWA during a period of over 40 years. In addition, the agencies 

were guided, in part, by the compelling need for clearer, more consistent and easily 

implementable standards to govern administration of the CWA, including brighter 

lines where feasible and appropriate.

Southern Environmental Law Center et al. (Doc. #13610)

8.51 Overall, we support the proposed rule’s approach to protecting tributary streams. The 

proposed rule provides more clarity and better corresponds to the robust science linking 

tributary streams with their downstream rivers.244 As stated above, small streams make up 

a majority of stream miles in the United States and making their impact on the chemical, 

physical and biological integrity of our waters indisputable. Of those streams, intermittent 

and ephemeral streams comprise a significant portion of the river network, underscoring 

the need for their protection. For example, in arid and semi-arid states including Arizona, 

New Mexico, Nevada, Utah, Colorado and California, over 81% of stream miles have 

been classified as ephemeral or intermittent.245 Even in some non-arid states, intermittent 

streams are predominant as in Alabama where 80% of stream miles in the National Forest 

are classified as intermittent.246 The value of these small streams for the nation’s clean 

 

243 Virginia Department of Environmental Quality comments on Advanced Notice of Public Rulemaking on 

definition of Waters of the US, EPA Docket OW-2002-0050, March 28, 2003.

244 See e.g., J.L. Meyer and J.B. Wallace, Lost linkages and lotic ecology: rediscovering small streams in Ecology: 

Achievement and Challenge 295-317 (M.C. Press et al. eds. 2001); M.J. Patz et al., Trace Elements in Coalbed 

Methane Produced Water Interacting with Semi- and Ephemeral Stream Channels, 170 Water Air and Soil Pollution 

55, 55-67 (2006); Judy E. Meyer et al., Where Rivers are Born: The Scientific Imperative for Defending Small 

Streams and Wetlands (2003), available at www.americanrivers.org/newsroom/resources/where-rivers-areborn- thescientific-imperative-for-defending-small-streams-and-wetlands/ (last visited Nov. 10, 2014).

245 Lainie R. Levick et al., The Ecological and Hydrological Significance of Ephemeral and Intermittent Streams in 

the Arid and Semi-arid American Southwest, U.S. Environmental Protection Agency and USDA/ARS Southwest 

Watershed Research Center, EPA/600/R-08/134, ARS/233046 (2008).

246 J.L. Meyer, et al., Comments of Professional Aquatic Scientists on Advanced Notice of Proposed Rulemaking for 

on the Clean Water Act Regulatory Definition of "Waters of the United States" (Docket ID No. OW-2002-0050) 

(2003).
Clean Water Rule Response to Comments – Topic 8: Tributaries

270

and safe drinking water is well recognized, providing drinking water for 117 million 

Americans,247 and yet is currently under threat.248

Headwater streams, whether perennial, ephemeral or intermittent impact downstream 

flooding, base flows, water quality and the entire aquatic, and in many cases, terrestrial 

food chain.249 Headwater streams prevent devastating floods by absorbing significant 

amounts of rainwater, runoff, and snowmelt. While headwaters comprise the smallest 

upstream component of a river network, they have the largest surface area of soil in 

contact with available water, thereby providing the greatest opportunity for groundwater 

recharge.250 Physical, chemical, and biological processes of headwaters retain and 

transform excess nutrients preventing them from entering downstream community water 

supplies, lakes and eventually estuaries. These headwaters not only provide numerous 

ecosystem services to humans but also provide vital habitat for numerous species. Most 

species spend at least some portion of their life cycle in these small perennial, ephemeral 

and intermittent streams. Preserving headwater streams under the Clean Water Act means 

cleaner water for larger downstream rivers, estuaries and oceans. It is well known that 

processes occurring upstream within these small streams affect the entire river network’s 

structure and function.

Given the critical nature of tributary streams, we are pleased to see the agencies’ reading 

of current law and science to continue its protection of tributary stream systems. 

Specifically, we support the presumptive coverage of non-navigable tributaries connected 

to navigable waters and the recognition of the cumulative impact of stream systems on 

downstream waters through application of Justice Kennedy’s direction to evaluate 

wetlands “alone or in combination with similarly situated wetlands in the region” to 

streams. We offer the following recommendations to strengthen the final rule to better 

protect tributaries and clean water. (p. 46-47)

Agency Response: The agencies agree with the commenter that headwater 

streams provide important functions that support the chemical, physical and 

biological integrity of downstream waters. The final rule, like the proposed rule, 

establishes categorical jurisdiction over all waters, including intermittent, 

ephemeral and headwater streams, which meet the definition of “tributary” and are 

not excluded in paragraph (b). In making this determination, the agencies relied not 

only on the science, but also on their technical expertise and practical experience in 

implementing the CWA during a period of over 40 years. In addition, the agencies 

are guided, in part, by the compelling need for clearer, more consistent and easily 

implementable standards to govern administration of the CWA, including brighter 

lines where feasible and appropriate.

 

247 U.S. Environmental Protection Agency, Geographic Information Systems Analysis of the Surface Drinking 

Water Provided by Intermittent, Ephemeral, and Headwater Streams in the U.S. [hereinafter EPA, GIA Analysis], 

http://water.epa.gov/lawsregs/guidance/wetlands/surface_drinking_water_index.cfm (last visited Nov. 10, 2014).

248 Charles Duhigg and Janet Roberts, Rulings Restrict Clean Water Act, Foiling EPA, New York Times, Feb. 28, 

2010 (quoting New York State Assistant Commissioner for Water Resources on the gaps left in clean water 

protections: “There are whole watersheds that feed into New York’s drinking water supply that are, as of now, 

unprotected.”), http://www.nytimes.com/2010/03/01/us/01water.html?pagewanted=all&_r=0.

249 Id. see also, supra note 147.

250 Meyer, supra note 144.
Clean Water Rule Response to Comments – Topic 8: Tributaries

271

8.52 We support EPA’s proposed analysis for cumulative analysis of similarly situated waters. 

Watershed networks are inherently connected, and failure to protect small upstream 

tributaries could result in “alterations [to] downstream hydrology, water quality, biota 

and geomorphic processes.”251 Once EPA or the Corps makes a determination that a 

tributary stream has a significant nexus to any traditional navigable waters or interstate 

water, all downstream stream segments by necessity must also be jurisdictional. EPA 

should make clear that field staff should document the tributary that was found to have a 

significant nexus with downstream traditional navigable waters or interstate waters as 

well as all waters in between the two to ensure those waters are clearly recognized as 

jurisdictional. This data should be widely available and be used to create an ongoing 

database of waters that are jurisdictional for continual development of the category of 

“similarly situated” waters. (p. 48)

Agency Response: The agencies agree with the commenter that headwater 

streams provide important functions that support the chemical, physical and 

biological integrity of downstream waters. The final rule, like the proposed rule, 

establishes categorical jurisdiction over all waters, including intermittent, 

ephemeral and headwater streams, which meet the definition of “tributary” and are 

not excluded in paragraph (b). In making this determination, the agencies relied not 

only on the science, but also on their technical expertise and practical experience in 

implementing the CWA during a period of over 40 years. In addition, the agencies 

are guided, in part, by the compelling need for clearer, more consistent and easily 

implementable standards to govern administration of the CWA, including brighter 

lines where feasible and appropriate.

National Wildlife Federation (Doc. #15020)

8.53 ...in the interest of improved clarity, we do support a reorganization of the first part of 

the tributary definition that more clearly identifies contribution of flow as the key 

element of every tributary, and specifies two categories of water bodies that function as 

tributaries and therefore meet the tributary definition. For example:

The term tributary means a water in either of the following two categories:

(a) a water which contributes flow, either directly or through another water, to a water 

identified in paragraphs (a)(1) through (a)(4) of this section, and which is physically 

characterized by the presence of a bed and banks and ordinary high water mark, as 

defined at 33 CFR 328.3(e); or

(b) wetlands, lakes, and ponds (even if they lack a bed and banks or ordinary high water 

mark), if they contribute flow, either directly or through another water, to a water 

identified in paragraphs (a)(1) through (a)(4) of this section.

While more clearly defined in regulation for the first time, the proposed tributary 

definition is essentially the same as the Corps’ working definition of tributary at the time 

of the Rapanos decision – a working definition referenced and seemingly supported by 

 

251 Mary C. Freeman et al., Hydrologic Connectivity and the Contribution of Stream Headwaters to Ecological 

Integrity at Regional Scales, 43 Journal of the American Water Resources Association 5, 6-14 (2007).
Clean Water Rule Response to Comments – Topic 8: Tributaries

272

Justice Kennedy in his Rapanos concurring opinion. Justice Kennedy suggests the current 

definition of tributary “may well provide a reasonable measure of whether specific minor 

tributaries bear a sufficient nexus with other regulated waters to constitute ‘navigable 

waters’ under the Act.”252 (p. 34-35)

Agency Response: The final rule, like the proposed rule, establishes categorical 

jurisdiction over all waters, including intermittent, ephemeral and headwater 

streams, which meet the definition of “tributary” and are not excluded in paragraph 

(b). In making this determination, the agencies relied not only on the science, but 

also on their technical expertise and practical experience in implementing the CWA 

during a period of over 40 years. In addition, the agencies are guided, in part, by 

the compelling need for clearer, more consistent and easily implementable 

standards to govern administration of the CWA, including brighter lines where 

feasible and appropriate. See summary responses for sections 8.1.1 and 8.1.2. The 

final rule eliminates the need to identify a water as relatively-permanent, or conduct 

a significant nexus determination for each tributary. Instead, the final rule 

establishes categorical jurisdiction over all waters that meet the definition of 

"tributary" and that are not excluded in paragraph (b). Section I of the Technical 

Support Document further discusses the legal issues concerning the final rule, 

including consistency with the statute and Supreme Court decisions. Section VII of 

the Technical Support Document discusses the science supporting the agencies' 

determination that waters meeting the definition of "tributary" have a significant 

nexus because they significantly affect the chemical, physical, and biological 

integrity of traditional navigable waters, interstate waters, and the territorial seas

and biological integrity of traditional navigable waters, interstate waters, and the 

territorial seas.

8.54 D. The agencies’ treatment of headwater and ephemeral streams is scientifically and 

legally sound.

The preamble to the proposed rule, including the Appendix A Science Evidence, includes 

the well-documented conclusion that:

Tributaries that are small, flow infrequently, or are a substantial distance from the 

nearest (a)(1) through (a)(3) water (e.g., headwater perennial, intermittent, and 

ephemeral tributaries) are essential components of the tributary network and have 

important effects on the chemical, physical, and biological integrity of (a)(1) 

through (a)(4) waters, contributing many of the same functions downstream as 

larger streams. When their functional contributions to the chemical, physical and 

biological conditions of downstream waters are considered at a watershed scale, 

the scientific evidence supports a legal determination that they meet the 

‘significant nexus’ standard articulated by Justice Kennedy in Rapanos. 79 Fed. 

Reg. 22206, 22231-32.124

For example, intermittent headwaters streams throughout the Rocky Mountain West 

contribute cold, clean water to larger perennial tributaries that flow into traditionally 

 

252 Id. at 2249.
Clean Water Rule Response to Comments – Topic 8: Tributaries

273

navigable or interstate waters. Fish move through both intermittent and ephemeral 

streams253 and fish and other aquatic species use these systems for certain life stages.254

The continued inclusion of ephemeral streams as tributaries and “waters of the United 

States” in accordance with the proposed rule is well supported by the scientific literature, 

the CWA, the case law, and past agency practice.255 EPA has estimated that intermittent 

or ephemeral streams comprise fifty-nine percent of all stream miles in the United States, 

excluding Alaska.256 As Western Resource Advocates notes in its Proposed Guidance 

Comments (July 2011), the vast majority of river miles in the Interior West are smaller 

headwaters and plains streams that do not flow year-round. EPA Region 8 estimates that 

only 17% of the waters within its five states flow year-round.257 In Colorado and Utah, 

respectively, only 25 and 21 percent of stream miles are perennial.258

In Arizona, an estimated 96% of the state’s stream miles are intermittent or ephemeral.259

Moreover, in Arizona, in the early 2000s, the State estimated that 97% of its permitted 

point source discharges were to headwaters, intermittent and ephemeral streams.260 In its 

 

253 Stefferud & Steffrud, “Fish Movement through Intermittent Stream Channels: A Case History Study” (2007), 

available at http://www.usbr.gov/lc/phoenix/biology/azfish/pdf/intermittentStreams.pdf.

254 Wigington, et al. “Coho Salmon Dependence on Intermittent Streams,” (2006), available at 

http://www.roguebasinwatersheds.org/files/intermittent%20streams%20and%20coho.pdf.

255 See, e.g., United States v. Deaton, 332 F.3d 698, 712 (4th Cir. 2003), cert denied, 124 S. Ct. 1874 (2004)

(“jurisdiction over the whole tributary system of any navigable waterway is warranted”); Quivira v. EPA, 765 F.2d 

126 (10th Cir. 1985) (arroyo with continuous groundwater connection and occasional surface water connection 

jurisdictional under the Act); United States v. Ashland Oil and Transportation Co., 504 F.2d 1317, 1325 (6th Cir. 

1974) (finding “Congress knew exactly what is was doing and that it intended the Federal Water Pollution Control 

Act to apply, as Congressman Dingell put it, ‘to all water bodies, including main streams and their tributaries.’ 

Certainly the Congressional language must be read to apply to our instant case involving pollution of one of the 

tributaries of a navigable river. Any other reading would violate the specific language of the definition [of navigable 

waters as waters of the United States] and turn a great legislative enactment into a meaningless jumble of words.”) 

(quoting 118 Cong. Rec. 33756-57).

256 Letter from Benjamin H. Grumbles, Assistant Administrator, U.S. Environmental Protection Agency to Jeanne 

Christie, Executive Director, Association of State Wetland Managers (Jan. 9, 2006) [mistakenly date stamped Jan. 9, 

2005] at 2.

257 See Congressionally Requested Report on Comments Related to Effects of Jurisdictional Uncertainty on Clean 

Water Act Implementation, Report No. 09-N-0149 at 8 (2009), available at 

http://www.epa.gov/oig/reports/2009/20090430-09-N-0149.pdf.

258 See Streams Lakes and Trout Streams of Colorado, 

http://www.cotrout.org/Portals/0/pdf/legislative/State%20of%20Colorado%20Ephmeral%20Comparison.pdf; EPA, 

Percentage of Surface Drinking Water from Intermittent, Ephemeral, or Headwater Streams in Utah, available at 

http://www.epa.gov/owow/wetlands/science/surface_drinking_water/pdfs/surface_drinking_water_ut.pdf (last 

visited 06/28/11).

259 See Letter from Stephen A. Owens, Director, Arizona Department of Environmental to Benjamin H. Grumbles, 

Assistant Administrator, Office of Water, U.S. Environmental Protection Agency (December 5, 2007) at 2 

(describing the quality and function of surface waters in Arizona) (submitted as comments on the Guidance) (2007 

ADEQ Comments); See NWF, NMWF, TU, DU, Imperiled Treasures: How Recent Supreme Court Decisions and 

Agency Actions Have Endangered Southwest Waters and Wildlife (January 2008) at 16; Nadeau & Rains, 

Hydrological Connectivity Between Headwater Streams and Downstream Waters: How Science can Inform Policy, 

43 J. Am. Water Resources Ass’n 118, Fig. 3b (2007), available at

http://www.albergstein.com/cao/Best%20Available%20Science/Headwater%20Streams/JAWRA%20Headwaters%

20Issue/Headwaters%20ecological%20connectivity%20-%20science%20and%20policy.pdf.

260 Id. at 127.
Clean Water Rule Response to Comments – Topic 8: Tributaries

274

comments on the 2007 Rapanos Guidance, the Arizona Department of Environmental 

Quality (ADEQ) acknowledged that without Clean Water Act jurisdiction over its 

intermittent and ephemeral streams, it “will be unable to assure the general public that 

these discharges of effluent in the desert are not harmful to the environment, and we will 

be unable to achieve our overall mission to enhance and protect Arizona’s 

environment.”261

The agencies’ rulemaking record also considers that, particularly in the West, some rivers 

and streams that are ephemeral today used to flow with greater frequency because of 

water supply infrastructure that has diverted the natural flows of these rivers and streams 

elsewhere.262 While the South Platte River in Colorado once flowed year round, today 

there are reaches of the South Platte where the flow in the river can be composed entirely 

of effluent from point source permitted discharges.263

Because the watersheds in the West have a high concentration of ephemeral streams, the 

contribution of these streams to the larger tributaries is critical to maintain tributary 

function, including the function of providing habitat to native species that even 

ephemeral streams provide. WRA notes, for example, one set of three small warm/cool 

water fishes – the bluehead sucker, the flannelmouth sucker and the roundtail chub – that 

is the subject of a conservation plan among Arizona, Colorado, Nevada, New Mexico, 

Utah and Wyoming.264 These fish occupy primarily headwaters tributaries, many of 

which are intermittent or ephemeral. In one study, the fish were found in deep pools 

above ephemeral reaches, indicating that both adult and juvenile fish move throughout 

their headwaters habitat, including along ephemeral channels.265

Natural and artificial ephemeral streams, even if they carry only stormwater (or effluent 

from point source discharges), eventually flow into intermittent or perennial tributaries or 

traditionally navigable or interstate waters. The pollutants in the storm water or effluent 

also find their way downstream. WRA offers the example that, in an effort to keep its 

drinking water source watershed as clean as possible, the Pagosa Area Water and 

Sanitation District has published a page on its website cautioning loggers to “avoid poor 

logging practices” that cause excessive sediment contributions to the larger system.266

There is agency precedent for regulating ephemeral streams. In 2007, the Arizona 

Department of Environmental Quality (ADEQ) commented to EPA that, “Arizona’s 

ephemeral streams have been considered jurisdictional waters at least since the first days 

 

261 2007 ADEQ Comments, Imperiled Treasures, supra note 131

262 See, e.g., 79 Fed. Reg. at 22201 citing U.S. v. Moses, 496 F. 3d 984 (9th Cir. 2007), cert. denied, 554 U.S. 918 

(2008); SAB Connectivity Peer Review Report at 31-32, 57-58; Western Resource Advocates 2014 Rule Comments 

at 9, 16.

263 Id. citing USGS, Water Quality in the South Platte River: Colorado, Nebraska & Wyoming 1992-1995, Circular 

1167 at 18 (1998).

264 Id. at 10, citing White Water Park at Rock Park, http://www.cityofsparks.us/residents/parks-andfacilities/whitewater-park-rock-park (last visited Oct. 3, 2014).

265 Michael R. Bower, et al., Habitat Features Affect Bluehead Sucker, Flannelmouth Sucker, and Roundtail Chub 

Across a Headwater Tributary System in the Colo. River Basin, 23 J. Freshwater Eco. 3, pp. 347-58 (Sept. 2008), 

available at http://www.uwyo.edu/frahel/pdfs/bower-2008-1.pdf.

266 Id. citing Watersheds, http://www.pawsd.org/watershed-protection.html (last visited Oct. 3, 2014).
Clean Water Rule Response to Comments – Topic 8: Tributaries

275

of the 1972 [Clean Water Act].”267 Prior to the 2007 guidance, the Los Angeles District 

often took jurisdiction on “dry washes,” at least where they could readily identify an 

Ordinary High Water Mark.268 In 2007, the Kansas City District found jurisdictional a 

first-order, ephemeral, stream based on the presence of a “significant nexus.”269 Even the 

2008 Guidance extended CWA jurisdiction to “[c]ertain ephemeral waters in the arid 

west” where they are “tributaries and they have a significant nexus to downstream 

traditional navigable waters. For example, in some cases these ephemeral tributaries may 

serve as a transitional area between the upland environment and the traditional navigable 

waters.”270 The 2008 Guidance failed to explain, however, why such waters outside of the 

arid West do not likewise provide important functions and warrant protection. (p. 39-41)

Agency Response: The agencies agree with the commenter that headwater 

streams provide important functions that support the chemical, physical and 

biological integrity of downstream waters. The final rule, like the proposed rule, 

establishes categorical jurisdiction over all waters, including intermittent, 

ephemeral and headwater streams, which meet the definition of "tributary" and are 

not excluded in paragraph (b). In making this determination, the agencies relied not 

only on the science, but also on their technical expertise and practical experience in 

implementing the CWA during a period of over 40 years. In addition, the agencies 

are guided, in part, by the compelling need for clearer, more consistent and easily 

implementable standards to govern administration of the CWA, including brighter 

lines where feasible and appropriate.

American Rivers (Doc. #15372)

8.55 In general, we are supportive of the Agencies’ approach to defining tributaries under the 

CWA. The proposed definition reflects the overwhelming scientific consensus that 

tributaries impact the chemical, physical, and biological integrity of downstream 

waters.271 Tributaries transport water, sediment, nutrients, and organisms downstream, 

capture and store floodwaters, filter out pollutants, and provide habitat for aquatic 

organisms, plants, and animals.272 As the scientific literature demonstrates, all tributaries 

have a significant nexus to jurisdictional waters and we support the Agencies’ decision to 

categorically protect them as “waters of the United States.”

Additionally, we are strongly supportive of the inclusion of intermittent, and ephemeral 

tributaries which make up approximately 60 percent of streams in the continental United 

 

267 2007 ADEQ Comments, Imperiled Treasures at 17, supra note 131.

268 Imperiled Treasures, supra, at 17.

269 See U.S. Army Corps of Eng’rs, Kansas City District, Approved Jurisdictional Determination: Coffey County 

RWD 3, NWK-2007-02080-2, at 5 (Dec. 6, 2007) (describing multiple effects of stream).

270 2008 Guidance at 11.

271 Definition of ‘Waters of the United States’ Under the Clean Water Act, 79 Fed. Reg. 76, 22201 (proposed April

21, 2014) [hereinafter Definition of WOTUS]. Letter from Dr. David T. Allen, Chair of the Science Advisory Board

to EPA Administrator Gina McCarthy, Science Advisory Board (SAB) Consideration of the Adequacy of the

Scientific and Technical Basis of the EPA’s Proposed Rule titled, “Definition of Waters of the United States Under

the Clean Water Act” 2 (Sep. 30, 2014) [hereinafter SAB review of the proposed rule].

272 Definition of WOTUS, 79 Fed. Reg. at 22226-22227.
Clean Water Rule Response to Comments – Topic 8: Tributaries

276

States and contribute to the drinking water supplies of 117 million Americans.273, 274 It is 

important to protect all tributaries under the CWA because they provide many functions, 

as discussed above, that directly affect the quality of downstream waters. We agree with 

the Agencies that, “It is necessary to regulate the entire tributary system to fulfill the 

objective of the CWA.”275

The legislative and judicial history of the CWA supports the comprehensive protection of 

tributaries. Justice Kennedy determined that “waters of the United States” encompasses 

waters that “possess a significant nexus to waters that are or were navigable in fact or that 

could reasonably be so made.”276 The significant nexus test is assessed in terms of the 

CWA’s goals to “restore and maintain the chemical, physical, and biological integrity of 

the Nation’s waters.”277 Tributaries clearly meet this “significant nexus” test. Justice 

Kennedy also rejected the plurality’s approach that only “relatively permanent” waters 

fall under the scope of the CWA.278 He stated that the requirement of “permanent 

standing water or continuous flow... makes little practical sense in a statute concerned 

with downstream water quality.”279 Thus, the inclusion of perennial as well as 

intermittent and ephemeral waters is appropriate under the CWA. (p. 17)

Agency Response: The final rule, like the proposed rule, establishes categorical 

jurisdiction over all waters, including intermittent, ephemeral and headwater 

streams, which meet the definition of "tributary" and are not excluded in 

paragraph (b). In making this determination, the agencies relied not only on the 

science, but also on their technical expertise and practical experience in 

implementing the CWA during a period of over 40 years. In addition, the agencies 

are guided, in part, by the compelling need for clearer, more consistent and easily 

implementable standards to govern administration of the CWA, including brighter 

lines where feasible and appropriate.

Western Resource Advocates (Doc. #16460)

8.56 V. To protect the West’s rivers and ecosystems, Clean Water Act protection must 

extend to all tributaries of navigable and interstate waters.

WRA agrees with the proposed rule, 42 C.F.R. §122(a)(5) and elsewhere, to define all 

tributaries of traditional navigable and interstate waters as waters of the US. EPA’s 

Science Advisory Board recently issued its final review of the agencies’ scientific support 

for this aspect of the rule, finding inter alia, that EPA’s review “provides strong scientific 

support for the conclusion that ephemeral, intermittent and perennial streams exert a 

strong influence on the character and functioning of downstream waters and that tributary 

 

273 Geographic Information Systems Analysis of the Surface Drinking Water Provided by Intermittent, Ephemeral,

and Headwater Streams in the U.S., supra note 63.

274 EPA, Streams (last updated Oct. 30, 2013), http://water.epa.gov/type/rsl/streams.cfm.

275 Definition of WOTUS, 79 Fed. Reg. at 22227

276 Rapanos, 547 U.S. at 759.

277 33 U.S.C. §1251(a) (2013).

278 Rapanos, 547 U.S. at 739.

279 Id. at 769.
Clean Water Rule Response to Comments – Topic 8: Tributaries

277

streams are connected to downstream waters.”280 If anything, the Science Advisory Board 

suggested that the justification for a finding of connectivity in at least one type of water 

(unidirectional non-floodplain wetlands), is stronger than the agency’s stated 

conclusion.281 In the arid and semi-arid southwest, where three quarters or more of river 

miles are intermittent and ephemeral, it is imperative to implement the Clean Water Act 

so that these tributaries be covered. In Colorado alone, as EPA has acknowledged, 3.7 

million people receive all or part of their drinking water from intermittent and ephemeral 

tributaries.282 To understand why, consider the map below, which shows perennial 

tributaries in blue, intermittent tributaries in red:283

Streams, Lakes and Reservoirs of Colorado

Intermittent Tributaries

Intermittent, or in the Rapanos plurality’s language, “seasonal,” streams contribute cold, 

clean water to larger perennial tributaries that flow into traditionally navigable or 

interstate waters. As is not true elsewhere in the country, the majority of river miles in the 

southwest are not perennial. Flows of many rivers and streams in this region fluctuate 

 

280 Letter from David Allen & Amanda Rodewald, EPA, to Gina McCarthy, EPA p.3 (Oct. 17, 2014 ) (regarding 

SAB Review of the Draft EPA Report, Connectivity of Streams and Wetlands to Downstream Waters: A Review 

and Synthesis of the Scientific Evidence) available at 

http://yosemite.epa.gov/sab/sabproduct.nsf/WebBoard/AF1A28537854F8AB85257D74005003D2/$File/EPA-SAB15-001+unsigned.pdf.

281 Id.

282 Envtl. Protection Agency, Analysis of Surface Drinking Water Provided By Intermittent, Ephemeral, and

Headwater Streams in the U.S (State-by-State) and (County-by-County) (2009), available at

http://water.epa.gov/lawsregs/guidance/wetlands/surface_drinking_water_index.cfm.

283 Andrew Todd, Aquatic Specialist, Trout Unlimited (2007) (White areas may be wetlands or uplands).
Clean Water Rule Response to Comments – Topic 8: Tributaries

278

based on a yearly hydrologic cycle of mountain snowmelt, resulting in a peak flow during 

late spring and early summer, followed by low or no flows the rest of the year.284 The 

southwest’s intermittent tributaries have ordinary high water marks and relatively well 

defined courses with beds and banks, although these waterways may move within the 

flood plain during floods, as do perennial tributaries and TNW. Fish move through 

intermittent tributaries far more often than once thought,285 and, fish (as well as other 

aquatic species) rely on these systems during certain of their life stages.286

Modern water development has also changed the character of tributaries in the West, 

transforming these waters both from intermittent to perennial and from perennial to 

intermittent. Thus, rivers like the South Platte (tributary to the Platte) which flows 

through Denver, have increased flows during what traditionally was their low (or no) 

flow season, because irrigation return flows or effluent discharges make up much, and at 

times all, of what flows down the river.287 While some regional rivers were intermittent 

pre-development, other southwestern rivers and streams that are today intermittent once 

flowed year-round in wet and average water years. The Salt River, a tributary to the 

Colorado that flows through and below Phoenix, Arizona, is one example; the Santa Fe 

River (tributary to the Rio Grande) through the City of Santa Fe in New Mexico is 

another. These rivers and streams now run dry – or flow only as a result of effluent 

discharges—because the region’s extensive system of dams and other water supply 

infrastructure has diverted or impounded the natural flows of these rivers and streams. As 

noted above, these tributaries include the primary river systems flowing through – and 

supplying drinking water to – some of the nation’s largest metropolitan areas. WRA 

supports inclusion of all of these tributaries as jurisdictional.

Ephemeral Tributaries

Ephemeral streams differ from intermittent streams in that ephemeral streams flow in 

response to precipitation events (rainstorms). Studies even document the movement of 

fish in and through ephemeral waters.288 Ephemeral streams must remain jurisdictional 

for the future effectiveness of Clean Water Act protections, especially in the arid and 

semi-arid Southwest. As noted above, the Tenth Circuit Court of Appeals, whose territory 

includes a substantial portion of this region, has repeatedly stated that Congress intended 

such streams be included as waters of the US.

Naturally ephemeral streams are important to the nation’s waters in many ways. Just as 

intermittent streams play an important role in watersheds in the Rockies, so too do 

ephemeral streams.289 In the southwest, a relatively higher percentage of native fish are 

 

284 Poff, Leroy, et al., The Natural Flow Regime, 47 BIOSCIENCE 769 (1997), available at

http://rydberg.biology.colostate.edu/~poff/Public/poffpubs/Poff1997(BioScience_NFR).pdf.

285 Sally E. Stefferud & Jerome A. Stefferud, Fish Movement Through Intermittent Stream Channels: A Case 

History Study (2007), available at http://www.usbr.gov/lc/phoenix/biology/azfish/pdf/intermittentStreams.pdf.

286 Wigington, et al., Coho Salmon Dependence On Intermittent Streams, (2006), available at 

http://www.esajournals.org/doi/abs/10.1890/1540-9295%282006%294%5B513%3ACSDOIS%5D2.0.CO%3B2 

(last visited Nov. 4, 2014).

287 USGS, Water Quality in the South Platte River: Colorado, Nebraska & Wyoming 1992-1995, Circular 1167 at 18 

(1998).

288 Stefferud, supra.

289 Levick, et al., supra.
Clean Water Rule Response to Comments – Topic 8: Tributaries

279

imperiled than in other areas of the country. Similarly, as a general matter, a higher 

percentage of terrestrial species are at risk for extinction than elsewhere in the nation.290

Because the region’s watersheds have a high concentration of ephemeral streams, the 

contribution of these streams to the larger tributaries is critical to maintaining tributary 

function, including providing habitat to native species in the ephemeral streams 

themselves. The Colorado River Basin is home to many native fish currently threatened 

from a variety of sources including pollutants, non-native fish, barriers and low flows 

caused by dams and diversions. One set of three small warm/cool water fishes – the 

bluehead sucker, the flannelmouth sucker and the roundtail chub – is the subject of a 

conservation plan among Arizona, Colorado, Nevada, New Mexico, Utah and 

Wyoming.291 Unlike the “big river” native fish on the Colorado that live in perennial 

rivers and adjacent wetlands, these smaller fish occupy primarily headwaters tributaries, 

many of which are intermittent or ephemeral. In one study, the fish were found in deep 

pools above ephemeral reaches, indicating that both adult and juvenile fish move 

throughout their headwaters habitat, including along ephemeral channels.292

Natural and artificial ephemeral streams, even if they carry only storm water, effluent 

from point source discharges or sediment from non-point source activities like road 

building and logging, eventually flow into intermittent or perennial tributaries or 

traditionally navigable or interstate waters. Thus, the pollutants in the storm water or 

effluent also find their way downstream and can have significant effects (positive or 

negative) downstream. For example, in an effort to keep its drinking water source 

watershed as clean as possible, the Pagosa Area Water and Sanitation District has 

published a page on its website cautioning loggers to “avoid poor logging practices” that 

cause excessive sediment contributions to the larger system.293

If there are numerous, similarly situated ephemeral streams in a single entry watershed, 

then their combined impact in terms of pollutant load on the tributary, navigable water or 

interstate water can be significant. From an efficiency standpoint, it will almost always be 

more efficient to control these pollutants at their source rather than wait to control them 

downstream, especially because the pollutants are likely to have adverse effects on the 

aquatic life or recreational opportunities along the way. As the Pagosa example 

demonstrates above, many public water suppliers divert in a headwaters system that 

receives flows and pollutants from upstream ephemeral and intermittent reaches. In the 

southwest, water users also divert directly from intermittent and even ephemeral streams 

during the times of the year when they flow.294 Thus, pollutant discharges to these small, 

seasonal waters must be controlled at their sources to protect the integrity of the region’s 

municipal and agricultural water supplies. (p. 10-13)

 

290 Walker & Burr, Status of Freshwater Fishes of the United States: Overview of an Imperiled Fauna, 19 Fisheries 

6 (1994).

291 Supra note 38.

292 Michael R. Bower, et al., Habitat Features Affect Bluehead Sucker, Flannelmouth Sucker, and Roundtail Chub 

Across a Headwater Tributary System in the Colo. River Basin, 23 J. Freshwater Eco. 3, pp. 347-58 (Sept. 2008), 

available at http://www.uwyo.edu/frahel/pdfs/bower-2008-1.pdf.

293 Watersheds, http://www.pawsd.org/watershed-protection.html (last visited Oct. 3, 2014).

294 Wendy Bowden Crowther, Clyde Snow & Sessions, P.C., Utah Water Law 101 (2009), available at

http://slco.org/watershed/symposium/pdf2009/Symp09Crowther.pdf.
Clean Water Rule Response to Comments – Topic 8: Tributaries

280

Agency Response: See summary response for section 8.1.1. The final rule, like the 

proposed rule, establishes categorical jurisdiction over all waters, including 

intermittent, ephemeral and headwater streams, which meet the definition of 

"tributary" and are not excluded in paragraph (b). In making this determination, 

the agencies relied not only on the science, but also on their technical expertise and 

practical experience in implementing the CWA during a period of over 40 years. 

The agencies’ interpretation is informed by the Science Report and the review and 

comments of the SAB, but not dictated by them. The rule reflects the judgment of 

the agencies when balancing the science, the statute, the Supreme Court opinions, 

the agencies’ expertise, and the regulatory goals of providing clarity to the public 

while protecting the environment and public.

8.57 Tributaries with a significant nexus when aggregated with other similar tributaries

WRA agrees that all intermittent and ephemeral streams within a single entry watershed 

will have a significant nexus on the downstream perennial navigable and interests waters 

if their effects are aggregated. For all of the scientific and legal reasons the agencies lay 

out in the Preamble, the appendices and the Connectivity Report, including the sources 

cited above and information from studies that WRA cited in our comments on the 

Guidance three years ago, WRA agrees with the agencies’ proposal to define all 

intermittent tributaries as jurisdictional, by rule, because they have a significant nexus to 

navigable and interstate waters.295 (p. 17)

Agency Response: See response provided immediately above.

National Waterways Conference, Inc. (Doc. #12979)

8.58 The definition contains no reference to the volume or frequency of flow, which would 

seem an important consideration in determining whether an area constitutes a "water" or 

not. That creates additional uncertainty and potential for jurisdictional overreaching. The 

definition thus could encompass impermanent waters that lack consistent flow, clearly 

deviating from the standard articulated by Justice Scalia in the Rapanos plurality 

opinion296 and raising serious problems under the "significant nexus" test. (p. 10)

Agency Response: See summary response for section 8.1.1. The definition of 

“tributary” in the final rule requires that flow must be of sufficient volume, 

frequency, and duration to create the physical characteristics of bed and banks and 

an ordinary high water mark. If a water lacks sufficient flow to create such 

characteristics, it is not considered “tributary” under this rule. Section VII of the 

Technical Support Document further discusses the science supporting the agencies’ 

conclusion that all waters that meet the definition of “tributary” and that are not 

 

295 The support for the agencies position is described in the preamble to the proposed rule, 79 Fed. Reg. 22188 

(April 21, 2014), EPA’s CONNECTIVITY OF STREAMS AND WETLANDS TO DOWNSTREAM WATERS: 

PEER REVIEW AND SYNTHESIS OF THE SCIENTIFIC EVIDENCE, available at 

http://yosemite.epa.gov/sab/sabproduct.nsf/fedrgstr_activites/7724357376745F48852579E60043E88C/$File/WOUS

_ERD2_Sep2013.pdf, and the EPA’s Science Advisory Board review thereof, supra note 45. WRA’s 2011 

comments on the proposed guidance are attached.

296 547 U.S. at 739 (finding that the agencies' authority should extend only to "relatively permanent, standing or 

continuously flowing bodies of water" connected to traditional navigable waters.).
Clean Water Rule Response to Comments – Topic 8: Tributaries

281

excluded in paragraph (b), have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. See also discussion in TSD and elsewhere discussing consistency of the rule 

with Supreme Court case law.

Trout Unlimited (Doc. #18015)

8.59 TU supports the proposal because it restores protection for headwater streams.

Connectivity and Clean Water Act jurisdictional protection are most important for small 

headwater streams and the trout and salmon that call them home. Unfortunately, the two 

Supreme Court decisions have put at risk the jurisdictional protection of the Clean Water 

Act for these small streams, particularly for ephemeral and headwater streams which may 

not flow the entire year. At least 80% of the stream miles in the country are headwater 

streams, with 53% of total stream length categorized as first-order streams. Headwater 

streams are incredibly important not only for downstream water quality, but also as 

habitat for trout and salmon. Lahontan cutthroat trout, for instance, exist entirely in 

terminal waters in the Great Basin Desert. Having already been extirpated from 90% of 

its stream habitat, over 70% of the remaining populations occupy only the highest 

headwater streams, many of which dry up seasonally before reaching mainstem rivers.

There are a variety of activities that threaten headwater streams. Increased development 

of natural gas, and the road building and land clearing associated with gas development, 

are prominent examples of the existing challenges our headwater streams are facing. (p. 

1-2)

Agency Response: The agencies agree with the commenter that headwater 

streams provide important functions that support the chemical, physical and 

biological integrity of downstream waters. The final rule, like the proposed rule, 

establishes categorical jurisdiction over all waters, including intermittent, 

ephemeral and headwater streams, which meet the definition of “tributary” and are 

not excluded in paragraph (b). In making this determination, the agencies relied not 

only on the science, but also on their technical expertise and practical experience in 

implementing the CWA during a period of over 40 years. In addition, the agencies 

are guided, in part, by the compelling need for clearer, more consistent and easily 

implementable standards to govern administration of the CWA, including brighter 

lines where feasible and appropriate.

Environment Council of Rhode Island (Doc. #3532)

8.60 Our organizations support the Agencies' proposal to define all tributaries as "waters of the 

United States," including headwaters and small streams that may only flow seasonally. 

Headwater streams provide most of the flow to downstream streams and rivers, and make 

up 54% of Rhode Island's stream miles. Intermittent and ephemeral streams may only 

flow during parts of the year, but they support water quality in downstream waters by 

filtering pollutants and capturing nutrients and make up 97% of Rhode Island's stream 

miles. These streams are also critical habitat for fish and other aquatic species. There is 

great potential for re-connecting and protecting the many miles of river and stream 

systems in RI, benefitting migratory fish species (salmon, river herring, shad) and also 

resident freshwater fish and wildlife populations (trout and freshwater mussels, crayfish). 
Clean Water Rule Response to Comments – Topic 8: Tributaries

282

Headwater and seasonal streams also feed the drinking water sources of 117 million 

Americans, including 564,893 residents in Rhode Island. Clarifying that all tributary 

streams, regardless of size or frequency of flow are covered under the Clean Water Act 

will restore protections to 169 miles of streams in Rhode Island that 54% of our residents 

depend on for drinking water. 

In addition, we support the Agencies' definition of tributary and strongly agree that 

ditches should be defined as "waters of the U.S." where they function as tributaries. There

is sufficient scientific evidence that some ditches function as tributaries moving water 

and pollutants downstream. In those cases protection is important. (p. 2)

Agency Response: The agencies agree with the commenter that headwater 

streams provide important functions that support the chemical, physical and 

biological integrity of downstream waters. The final rule, like the proposed rule, 

establishes categorical jurisdiction over all waters, tributary ditches and other manmade or man-altered waters that meet the definition of “tributary” and are not 

excluded in paragraph (b). In making this determination, the agencies relied not 

only on the science, but also on their technical expertise and practical experience in 

implementing the CWA during a period of over 40 years. In addition, the agencies 

are guided, in part, by the compelling need for clearer, more consistent and easily 

implementable standards to govern administration of the CWA, including brighter 

lines where feasible and appropriate.

Clean Water Action et al. (Doc. #13997)

8.61 We support the Agencies' proposal to define all tributaries as "waters of the United 

States," including headwaters and small streams that may only flow seasonally. 

Headwater streams provide most of the flow to downstream streams and rivers, and make 

up 29 percent of Florida's stream miles. Intermittent and ephemeral streams may only 

flow during parts of the year, but they support water quality in downstream waters by 

filtering pollutants and capturing nutrients and make up 12 percent of Florida's stream 

miles. 

These streams are also critical habitat for fish and other aquatic species. Headwater and 

seasonal streams also feed the drinking water sources of 117 million Americans. 

Clarifying that all tributary streams, regardless of size or frequency of flow are covered 

under the Clean Water Act will restore protections to 580 miles of headwater, intermittent 

and ephemeral streams in Florida that supply drinking water sources. 

In addition, we support the Agencies' definition of tributary and strongly agree that

ditches should be defined as "waters of the U.S." where they function as tributaries. There

is sufficient scientific evidence that some ditches function as tributaries moving water 

and pollutants downstream. In those cases protection is important. (p. 2)

Agency Response: See response to Environment Council of Rhode Island (Doc. 

#3532) above.

Kansas Natural Resource Council (Doc. #14599)

8.62 Ephemeral and Intermittent waters
Clean Water Rule Response to Comments – Topic 8: Tributaries

283

We are pleased to see in the proposed rule statements that speak specifically to the nature 

and importance of intermittent and ephemeral streams. A 2012 report by the Kansas 

Department of Health and Environment found that only 41% of the State’s stream 

mileage designated to support aquatic life actually does at the level required by the Clean 

Water Act. Many of the waterways in the western third of Kansas are intermittent or 

ephemeral and are therefore not perceived as affecting to any great degree downstream 

perennial flows, the so-called “real” navigable waters. The proposed rule and companion 

scientific report firmly establish that ephemeral streams are important and unique aquatic 

habitat and are critical contributors to downstream water quality. (p. 1)

Agency Response: The agencies agree with the commenter that ephemeral and 

intermittent tributaries provide important functions that support the chemical, 

physical and biological integrity of downstream waters. Any water meeting the 

definition of "tributary," as stated in the final rule, has a significant nexus to 

traditional navigable waters, interstate waters, or the territorial seas, and is 

therefore considered a “waters of the United States.” In making this determination, 

the agencies relied not only on the science, but also on their technical expertise and 

practical experience in implementing the CWA during a period of over 40 years. In 

addition, the agencies were guided, in part, by the compelling need for clearer, more 

consistent and easily implementable standards to govern administration of the 

CWA, including brighter lines where feasible and appropriate. 

Mystic River Watershed Association (Doc. #14633)

8.63 Our organization supports the Administration’s efforts to clarify that all tributaries –

including intermittent, ephemeral, and headwater streams – are “waters of the United 

States” and should be protected under the law. These streams feed into iconic waterways 

from the Chesapeake Bay to the Great Lakes to Puget Sound. (p. 2) commenter’s 

examples.

Agency Response: See response to Kansas Natural Resource Council (Doc. 

#14599) above.

Citizens Committee to Complete the Refuge (Doc. #14738.1)

8.64 We concur that the scientific literature conclusively demonstrates that "all tributary 

streams, including perennial, intermittent, and ephemeral streams are chemically, 

physically, and biologically connected to downstream rivers," and that they clearly 

warrant regulation under the Clean Water Act. (p. 2)

Agency Response: See response to Kansas Natural Resource Council (Doc. 

#14599) above.

Montana Audubon (Doc. #14755)

8.65 3. Streams that have a bed, bank, and Ordinary High Water Mark (OHWM).

Currently it is unclear which streams are included in WOUS. The proposed rule therefore 

clarifies that ephemeral, intermittent, perennial, and streams that run underground for a 

distance can be included in the definition of WOUS if they have a bed, bank, and 

OHWM. This makes sense—only those streams with water running through them 
Clean Water Rule Response to Comments – Topic 8: Tributaries

284

regularly will develop these features; and streams with water running through them 

regularly should be protected under the Clean Water Act.

In the map appearing [below], the project site for Corps permit NWO-2013-01330-MTB 

was considered non-jurisdictional, despite the fact that the adjacent stream was perennial 

with a bed, banks and OHWM, because of the one-mile (+) length of stream that flowed 

underground. The project site is marked in red. Allowing perennial streams that run 

underground for even a mile to be considered WOUS is important if we are to protect 

water quality long-term.

5,802 feet from end of Big Lost Creek Bowser-Tracy Ditch to Spring Creek

(p. 4)

Agency Response: See summary responses for sections 8.1.1 and 8.3. Under the 

final rule, a water that otherwise qualifies as a tributary under this definition does 

not lose its status as a tributary if, for any length, there are one or more natural 

breaks (such as a stream that flows underground) so long as a bed and banks and an 

ordinary high water mark can be identified upstream of the break.”

Clean Water Action et al. (Doc. #14884)

8.66 For the last decade, polluter-backed loopholes in the Clean Water Act have caused 

confusion about which streams, wetlands and other water are protected from pollution 

and destruction. Headwater and seasonal streams feed the drinking water sources of 117 

million Americans, including 2.2 million residents in Connecticut. Clarifying that all 

tributary streams, regardless of size or frequency of flow are covered under the Clean 

Water Act will restore protections to 844 miles of streams that 63% of our residents 

depend on for drinking water. This number includes 100% of those who depend on public 

water supplies

...

Our organizations support the Agencies’ proposal to define all tributaries as “waters of 

the United States,” including headwaters and small streams that may only flow 

seasonally. Headwater streams – streams that have no other streams flowing into them -

account for 52% of the total stream miles in Connecticut. Intermittent and ephemeral 
Clean Water Rule Response to Comments – Topic 8: Tributaries

285

streams may only flow during parts of the year, but they support water quality in 

downstream waters by filtering pollutants and capturing nutrients and make up 8% of 

Connecticut’s stream miles. These streams are also critical habitat for fish and other 

aquatic species. (p. 1, 2)

Agency Response: The agencies agree with the commenter that headwater 

streams provide important functions that support the chemical, physical and 

biological integrity of downstream waters. The final rule, like the proposed rule, 

establishes categorical jurisdiction over all waters, including intermittent and 

ephemeral stream that meet the definition of “tributary” and are not excluded in 

paragraph (b). In making this determination, the agencies relied not only on the 

science, but also on their technical expertise and practical experience in 

implementing the CWA during a period of over 40 years. In addition, the agencies 

are guided, in part, by the compelling need for clearer, more consistent and easily 

implementable standards to govern administration of the CWA, including brighter 

lines where feasible and appropriate.

Amigos Bravos (Doc. #14974)

8.67 In New Mexico, where up to 94% of our waters are intermittent and ephemeral,

297 we 

strongly support the clarification that Clean Water Act protections apply to streams that 

flow only seasonally. (See Figure 1 below for map of intermittent and ephemeral waters 

in New Mexico.) Since the US Supreme Court decisions in the Rapanos and Carabell 

cases there has been a loss of historic protections for many of our small streams which 

provide clean water for drinking, irrigation and wildlife in New Mexico. These Supreme 

Court decisions have made it confusing and burdensome for the U.S. Environmental 

Protection Agency (EPA) and U.S. Army Corps of Engineers to protect small streams 

and wetlands under the Clean Water Act. As a result, enforcement actions against 

polluters have declined, and it has become clear that some polluters are using the 

decisions as a justification to avoid permitting and reporting requirements for discharging 

pollutants into our waters. The Rule would clarify that some of the waters that have lost 

protections in the confusion after the Supreme Court decisions, namely ephemeral and 

intermittent tributaries, are once again protected under the Clean Water Act.

 

297 See 2010-2012 State of New Mexico Clean Water Act 303d/305b Integrated Report, page 4. Available at: 

http://www.nmenv.state.nm.us/swqb/303d-305b/2010-2012/.
Clean Water Rule Response to Comments – Topic 8: Tributaries

286

Figure 1: Types of New Mexico Surface Waters

...

I. Importance of Ephemeral and Intermittent Waters in New Mexico

Ephemeral waters are critically important for the health of New Mexico’s communities, 

wildlife and economy. A search of the New Mexico Department of Game and Fish’s 

BISON-M database shows that almost one fifth of NM vertebrate species, excluding fish, 

(127 species) use ephemeral and/or intermittent waters (list attached as Exhibit 1). These 

127 vertebrate species include: 9 taxa classified as State and/or federal threatened, 

endangered or candidate; 8 taxa classified as State and/or federal sensitive or species of 

concern 24 taxa classified as State “Species of Greatest Conservation Need”; 25 game 

species; 1 taxa endemic to NM; and 10 species listed as of cultural importance to Pueblo 

Tribes (Exhibits 2 and 3). Even some fish use ephemeral waters. For example, Pecos 

Pupfish and White Sands Pupfish (both State Threatened, State “Species of Greatest 

Conservation Need”, and federal Species of Concern) are exploiters which will move into 

ephemeral waters when available. The New Mexico Department of Game and Fish 

(NMDGF) actively manages 17 isolated wetlands and five intermittent streams (Mimbres 

River, Running Water Draw, Tularosa Creek, Three Rivers,Tajique Creek) to provide 

fishing opportunities for resident and non-resident anglers.298

Ephemeral waters are essential for all three species of spadefoot toads in New Mexico. 

Spadefoots stay burrowed in the soil (several years has been documented) until 

 

298 Letter from Larry Bell, Director of the New Mexico Department of Game and Fish to EPA (NMDGF comment 

letter on the 2003 ANPRM), April 15, 2003, at 5.
Clean Water Rule Response to Comments – Topic 8: Tributaries

287

conditions are suitable for breeding. Emergence from burrows is triggered by 

thunderstorms and breeding occurs quickly (as short as one night) in ephemeral waters. 

Eggs hatch in as little as 15 hours, and tadpoles metamorphose and leave the ephemeral 

waters in as little as 13 days. Ephemeral waters also appear to be important to Box 

Turtles, Garter Snakes, and tiger salamanders. Many of crustaceans and insects also occur 

in ephemeral and intermittent streams.

Protecting ephemeral and intermittent waters in New Mexico is essential for protecting 

public health. EPA estimates that 280,000 people in New Mexico receive drinking water 

from sources that rely at least in part on ephemeral, intermittent or headwater streams 

(Exhibit 4).299 These impacts are not hypothetical as there have been numerous instances 

of ephemeral waters being found not jurisdictional in New Mexico.300 (p. 3-4)

Agency Response: The agencies agree with the commenter that ephemeral and 

intermittent stream not only provide important functions that support the chemical, 

physical and biological integrity of downstream waters, but serve as valuable 

drinking waters sources in New Mexico. The final rule, like the proposed rule, 

establishes categorical jurisdiction over all waters, including intermittent and 

ephemeral stream that meet the definition of “tributary” and are not excluded in 

paragraph (b). In making this determination, the agencies relied not only on the 

science, but also on their technical expertise and practical experience in 

implementing the CWA during a period of over 40 years. In addition, the agencies 

are guided, in part, by the compelling need for clearer, more consistent and easily 

implementable standards to govern administration of the CWA, including brighter 

lines where feasible and appropriate.

Clean Water Action Maryland et al. (Doc. #15072)

8.68 Our organizations support the proposed rule for the clear protections it restores to 

headwaters, intermittent and ephemeral streams, and to wetlands and other waters 

located near or within the floodplain of these tributaries. We urge the Agencies to 

strengthen the final rule by further clarifying that important wetlands and other 

waters located beyond floodplains are also categorically protected under the Clean 

Water Act.

Headwater and seasonal streams feed the drinking water sources of 117 million 

Americans, including 3,990,016 residents in Maryland. Clarifying that all tributary 

streams, regardless of size or frequency of flow are covered under the Clean Water Act 

will restore protections to 2210 miles of streams in Maryland that 77% of our residents 

depend on for drinking water. In the Baltimore City area that’s roughly 1.6 million people 

and 100% of City residents.

Millions of small streams and wetlands provide most of the flow to our most treasured 

rivers that feed the Chesapeake Bay. If we do not protect these streams and wetlands, we 

 

299 Note that this analysis was conducted in 2006 prior to the surface water diversions for the cities of Albuquerque 

and Santa Fe going online, so this number is most likely substantially greater now.

300 See SPA-2007-636-ABQ, SPA-2007-00677-ABQ, SPA-2007-442-ABQ, SPA-2007-3540-ABQ, SPA-2008-54-

AQB (research was conducted only for 2007 and 2008 and is not comprehensive)
Clean Water Rule Response to Comments – Topic 8: Tributaries

288

cannot protect the livelihood on which communities and local economies depend. 

Leaving critical water resources vulnerable jeopardizes drinking water sources, public 

health and quality of life, as well as jobs and revenue for businesses that depend on clean 

water, including commercial fishing, outdoor activities and water-based recreation.

Our organizations support the Agencies’ proposal to define all tributaries as 

“waters of the United States,” including headwaters and small streams that may 

only flow seasonally. Headwater streams, streams that have no other streams feeding into 

them, provide most of the flow to downstream streams and rivers, and account for 59% of 

the total stream miles in Maryland. In 2007, EPA estimated that 46% of individual 

NPDES discharge permits in Maryland are for discharges into headwater streams, 

including some streams that do not flow year round.

Intermittent and ephemeral streams may only flow during parts of the year, but they 

support water quality in downstream waters by filtering pollutants and capturing nutrients 

and making up 19% of streams in Maryland do not flow year round. These streams are 

also critical habitat for fish and other aquatic species. There is great potential for reconnecting and protecting the many miles of river and stream systems flowing throughout 

Maryland and into the Chesapeake Bay. These waters benefit resident freshwater and 

saltwater fish and wildlife alike, contributing significantly to the state’s economy in 

commercial fishing industry, recreation and tourism. (p. 1-2)

Agency Response: The agencies agree with the commenters that ephemeral and 

intermittent stream provide important functions that support the chemical, physical 

and biological integrity of downstream waters and can be valuable sources of 

drinking water. The final rule establishes categorical jurisdiction over all waters 

that meet the definition of “tributary” and are not excluded in paragraph (b). The 

definition of “tributary” in the final rule requires physical indicators of bed and 

bank and an ordinary high water mark. These physical indicators demonstrate 

there is sufficient volume, frequency and duration of flow to significantly affect 

downstream waters. In making this determination, the agencies relied not only on 

the science, but also on their technical expertise and practical experience in 

implementing the CWA during a period of over 40 years. In addition, the agencies 

are guided, in part, by the compelling need for clearer, more consistent and easily 

implementable standards to govern administration of the CWA, including brighter 

lines where feasible and appropriate.

Environmental Justice Coalition for Water (Doc. #15105)

8.69 The Environmental Justice Coalition for Water supports the Administration's efforts to 

clarify that all tributaries - including intermittent, epbemera1, and headwater streams - are 

-waters of the United States and should be protected under the law. (p. 2)

Agency Response: The final rule, like the proposed rule, establishes categorical 

jurisdiction over all waters, including intermittent and ephemeral stream that meet 

the definition of “tributary” and are not excluded in paragraph (b). In making this 

determination, the agencies relied not only on the science, but also on their technical 

expertise and practical experience in implementing the CWA during a period of 

over 40 years. In addition, the agencies are guided, in part, by the compelling need 
Clean Water Rule Response to Comments – Topic 8: Tributaries

289

for clearer, more consistent and easily implementable standards to govern 

administration of the CWA, including brighter lines where feasible and 

appropriate.

Friends of the Cacapon River (Doc. #15121)

8.70 As a watershed organization caring for a headwater tributary, we believe that defining 

intermittent, ephemeral, and headwater streams as "Waters of the U.S." provides 

important clarification to the Clean Water Act's jurisdiction.

The Supreme Court opined that the EPA and Army Corps of Engineers must demonstrate 

a significant nexus between, among others, headwaters and downstream waters. EPA's 

assessment, titled Connectivity of Streams and Wetlands to Downstream Waters, presents 

a review and synthesis of more than 1,000 pieces of scientific literature. This assessment 

was reviewed by the independent Science Advisory Board, or SAB.

In its report to EPA, the SAB found that "the literature review provides strong scientific 

support for the conclusion that ephemeral, intermittent, and perennial streams exert a 

strong influence on the character and functioning of downstream waters and that tributary 

streams are connected to downstream waters" This review of scientific literature presents 

hard evidence that providing drinking water to West Virginians as well as millions of 

Americans along the Potomac and Ohio rivers downstream depends in part on healthy 

headwaters in West Virginia. (p. 1)

Agency Response: The agencies agree with the commenter that headwater 

streams provide important functions that support the chemical, physical and 

biological integrity of downstream waters. The final rule, like the proposed rule, 

establishes categorical jurisdiction over all waters, including intermittent and 

ephemeral stream that meet the definition of “tributary” and are not excluded in 

paragraph (b). In making this determination, the agencies relied not only on the 

science, but also on their technical expertise and practical experience in 

implementing the CWA during a period of over 40 years. In addition, the agencies 

are guided, in part, by the compelling need for clearer, more consistent and easily 

implementable standards to govern administration of the CWA, including brighter 

lines where feasible and appropriate.

Tulane Environmental Law Clinic et al (Doc. #15123)

8.71 Although we believe that the Act’s invocation of interstate commerce provides an equally 

valid reason for the proposed Rule’s clarification of “waters of the United States,”301 we 

also support its science-based determination that all tributaries, including “ephemeral” 

and “intermittent” streams, are categorically waters of the United States because they are 

physically, chemically and biologically connected to traditionally navigable waters...

A. Tributaries must be categorically protected.

 

301 The current regulations define “waters of the U.S.” as including “[a]ll other waters ... the use, degradation or 

destruction of which could affect interstate or foreign commerce. . . .” 40 C.F.R. § 110.1 (definition of navigable 

waters). This provision was left untouched by SWANCC and Rapanos.
Clean Water Rule Response to Comments – Topic 8: Tributaries

290

We support the decision to provide categorical protection for all tributaries. The proposed 

Rule clarifies which small streams and headwaters are covered by the CWA. Paragraph 

(s)(5) recognizes “tributaries” as waters of the United States, and defines “tributary” as “a 

water physically characterized by the presence of a bed and banks and ordinary high 

water mark, as defined at 33 C.F.R. § 328.3(e), which contributes flow, either directly or 

through another water, to a water identified in paragraphs (s)(1) through (4) of [the 

proposed Rule].”302 Tributaries are further defined to include wetlands, lakes, ponds, 

and—notably—headwater streams.303

...Categorical protection of all tributaries, including headwaters is essential, because 

tributaries connect the river network and provide vital ecosystem functions. The 

importance of headwater streams and wetlands to the health of larger, navigable rivers 

like the Mississippi cannot be overstated.

The structure and function of downstream waters are highly dependent on the 

constituent materials contributed by and transported through water bodies located 

elsewhere in the watershed. Most of the materials in a river, including water, 

sediment, wood, organic matter, nutrients, chemical contaminants, and certain 

organisms, originate outside of the river, from upstream tributaries, wetlands, or 

other components of the river system, and are transported to the river by water 

movement, wind, or other means.304

The evidence of connectivity between headwater streams and larger rivers is well 

established. Most rivers receive the majority of their water from tributaries rather than 

through direct precipitation or from groundwater.305 Roughly half of the water of larger 

tributaries and rivers originates from headwater streams.306

Additionally, studies show that nutrients and other substances are exported from small 

prairie streams307 and can significantly affect downstream water quality.308 Ecosystem 

 

302 Definition of “Waters of the United States” Under the Clean Water Act, 79 Fed. Reg. 22,188, 22,269 (proposed

Apr. 21, 2014) (to be codified at 40 C.F.R. pts. 110, 112, 116, 117, 122, 230, 232, 300, 302 & 401).

303 Id.

304 U.S. EPA, Office of Research & Development, Connectivity of Streams and Wetlands to Downstream Waters:

A Review and Synthesis of the Scientific Evidence – External Review Draft (Sept. 2013) (hereinafter

“Connectivity Report”), p. 1-4.

305 Winter, T. C. 2007. The role of groundwater in generating streamflow in headwater areas and in maintaining base 

flow. Journal of the American Water Resources Association 43:15-25; Bukaveckas, P. A. 2009. Rivers. Pages 721-

732 in G. E. Likens, editor. Encyclopedia of Inland Waters. Elsevier, Oxford, UK.

306 Connectivity Report at 4-20.

307 Dodds, W. K., J. M. Blair, G. M. Henerbry, J. K. Koelliker, R. Ramundo, and C. M. Tate. 1996a.Nitrogen 

transport from tallgrass prairie watersheds. Journal of Environmental Quality 25:973-981.
Clean Water Rule Response to Comments – Topic 8: Tributaries

291

functions provided by headwaters include denitrification, which removes nitrate from 

stream water through transformation to atmospheric nitrogen. Denitrification is 

widespread among headwater streams309 including the small streams of the Mississippi 

River Basin.310 In fact, one study found that uptake and transformation of inorganic 

nitrogen were most rapid in the smallest streams.311 Small tributaries also affect the 

downstream delivery of nutrients through abiotic processes wherein nutrients adsorb to 

stream sediments.312 Yet another study found that small streams deliver less nitrogen and 

phosphorus to the Gulf of Mexico than larger rivers due to increased in-stream nutrient 

uptake and removal by smaller streams.313 According to the Connectivity Report, “Even 

infrequent flows through ephemeral or intermittent channels influence fundamental 

biogeochemical processes....”314

Nearly two million miles of the nation‘s streams – about 59 percent of the total -- outside 

of Alaska are intermittent or ephemeral.315 For the main-stem states of the Mississippi 

River, the value of streams measured as intermittent or ephemeral streams, or otherwise 

noted as headwater streams (no known tributary), cannot be understated. To our 

knowledge, there are two known and published counts for ephemeral and intermittent 

stream miles for the nation and each individual state. EPA has long cited the information 

conveyed in Table 1, which uses the National Hydrography Dataset 1:100,000 scale. This 

table demonstrates the percentage of streams in the Basin states that are not the recipient 

of any tributaries (% Start Reach), and the percentage of streams that are considered 

intermittent or ephemeral.

 

308 Kemp, M. J., and W. K. Dodds. 2002. Comparisons of nitrification and denitrification in prairie and 

agriculturally influenced streams. Ecological Applications 12:998-1009. Dodds, W. K., K. Gido, M. R. Whiles, K. 

M. Fritz, and W. J. Matthews. 2004. Life on the edge: The ecology of Great Plains prairie streams. Bioscience 

54:205-216. Dodds, W. K., and R. M. Oakes. 2006. Controls on nutrients across a prairie stream watershed: Land 

use and riparian cover effects. Environmental Management 37:634-646. Several additional studies have documented 

the export of phosphorus from headwater streams to traditionally navigable waters in the Mississippi River Basin. 

Royer, T. V., M. B. David, and L. E. Gentry. 2006. Timing of riverine export of nitrate and phosphorus from 

agricultural watersheds in Illinois: Implications for reducing nutrient loading to the Mississippi River. 

Environmental Science & Technology 40:4126-4131; Bayless, M. A., M. G. McManus, and J. F. Fairchild. 2003. 

Geomorphic, water quality and fish community patterns associated with the distribution of Notropis topeka in a 

Central Missouri watershed. American Midland Naturalist 150:58-72; and Jacobson, L. M., M. B. David, and L. E. 

Drinkwater. 2011. A spatial analysis of phosphorus in the Mississippi River basin.

Journal of Environmental Quality 40:931-941.

309 Mulholland, P. J., et al., 2008. Stream denitrification across biomes and its response to anthropogenic nitrate 

loading. Nature 452:202-205.

310 Alexander, R. G., R. A. Smith, and G. E. Schwarz. 2000. Effect of stream channel size on the delivery of nitrogen 

to the Gulf of Mexico. Nature 403:758-761.

311 Peterson, B. J., W. M. Wollheim, P. J. Mulholland, J. R. Webster, J. L. Meyer, J. L. Tank, E. Martí, W. B.

Bowden, H. M. Valett, A. E. Hershey, W. H. McDowell, W. K. Dodds, S. K. Hamilton, S. Gregory, and D. D.

Morrall. 2001. Control of nitrogen export from watersheds by headwater streams. Science 292:86-90.

312 Meyer, J. L. 1979. The role of sediments and bryophytes in phosphorus dynamics in a headwater stream 

ecosystem. Limnology and Oceanography 24:365-375.

313 Alexander (2000); Alexander, R. B., R. A. Smith, G. E. Schwarz, E. W. Boyer, J. V. Nolan, and J. W. Brakebill.

2008. Differences in phosphorus and nitrogen delivery to the Gulf of Mexico from the Mississippi River basin.

Environmental Science & Technology 42:822-830.

314 Connectivity Report at 1-7.

315 Letter from Benjamin H. Grumbles, Assistant Administrator for Water, U.S. EPA, to Jeanne Christie, Executive 

Director, Association of State Wetland Managers, at 2 (Jan. 9, 2006) (mis-dated as Jan. 9, 2005).
Clean Water Rule Response to Comments – Topic 8: Tributaries

292

Table 1. Percentage of Non-Navigable Stream Miles316

State: Minnesota 

% Start Reach: 45

% Intermittent/Ephemeral: 51

State: Wisconsin 

% Start Reach: 53

% Intermittent/Ephemeral: 45

State: Illinois 

% Start Reach: 56

% Intermittent/Ephemeral: 55

State: Iowa 

% Start Reach: 59

% Intermittent/Ephemeral: 62

State: Missouri 

% Start Reach: 58

% Intermittent/Ephemeral: 66

State: Kentucky 

% Start Reach: 55

% Intermittent/Ephemeral: 29

State: Tennessee 

% Start Reach: 60

% Intermittent/Ephemeral: 28

State: Arkansas 

 

316 Natural Resources Defense Council, Missing Protection: Polluting the Mississippi River Basin’s Small Streams 

and Wetlands. NRDC Issue Paper, p. 21 (2008).
Clean Water Rule Response to Comments – Topic 8: Tributaries

293

% Start Reach: 52

% Intermittent/Ephemeral: 63

State: Mississippi 

% Start Reach: 55

% Intermittent/Ephemeral: 58

State: Louisiana 

% Start Reach: 38

% Intermittent/Ephemeral: 36

Alternatively, in the lead up to the proposed Rule, EPA had maps made for each state 

using the National Hydrography Dataset 1:24,000 scale (Table 2). These maps conveyed 

the cumulative length of intermittent and ephemeral streams in each state, and the 

percentage of a state’s overall stream mileage represented by ephemeral and intermittent 

streams.

Table 2. Percentage of Non-Navigable Stream Miles317

State: Minnesota 

Stream Miles Intermittent/Ephemeral: 38,116

% Stream Miles Intermittent/Ephemeral: 44

State: Wisconsin 

Stream Miles Intermittent/Ephemeral: 42,145

% Stream Miles Intermittent/Ephemeral: 57

State: Illinois

Stream Miles Intermittent/Ephemeral: 78,763

% Stream Miles Intermittent/Ephemeral: 73

State: Iowa 

Stream Miles Intermittent/Ephemeral: 72,258

 

317 U.S. Environmental Protection Agency: Streams and Waterbodies Maps, the National Hydrography Dataset,

High Resolution (October, 2013). Prepared by INDUS Corporation under contract with U.S. EPA, Office of

Water, and published on the House Committee on Science, Space, and Technology webpage:

http://science.house.gov/epa-maps-state-2013
Clean Water Rule Response to Comments – Topic 8: Tributaries

294

% Stream Miles Intermittent/Ephemeral: 70

State: Missouri 

Stream Miles Intermittent/Ephemeral: 94,416

% Stream Miles Intermittent/Ephemeral: 56

State: Kentucky 

Stream Miles Intermittent/Ephemeral: 51,960

% Stream Miles Intermittent/Ephemeral: 65

State: Tennessee 

Stream Miles Intermittent/Ephemeral: 31,851

% Stream Miles Intermittent/Ephemeral: 32

State: Arkansas 

Stream Miles Intermittent/Ephemeral: 90,032

% Stream Miles Intermittent/Ephemeral: 74

State: Mississippi 

Stream Miles Intermittent/Ephemeral: 105,236

% Stream Miles Intermittent/Ephemeral: 80

State: Louisiana 

Stream Miles Intermittent/Ephemeral: 58,458

% Stream Miles Intermittent/Ephemeral: 57

Though the numbers vary between these two different tables, the general and 

overwhelming consensus is that ephemeral and intermittent streams make up a 

significant, and in some cases, majority, of the hydrologic network in states up and down 

the Mississippi River. These waters are extremely prevalent, and have significant 

influence on the downstream water quality and quantity in traditionally navigable waters.

Likewise, intermittent and ephemeral streams have significant influence upon public 

drinking water sources throughout the Mississippi River states. In these ten states alone, 
Clean Water Rule Response to Comments – Topic 8: Tributaries

295

more than 16 million people depend to some degree on non-navigable streams for their 

drinking water.318

Table 3. Non-Navigable Streams as Drinking Water Sources319

State: Minnesota 

Population Served By SWPA Containing Non-Navigable Streams: 978,928

State: Wisconsin 

Population Served By SWPA Containing Non-Navigable Streams: 391,531

State: Illinois 

Population Served By SWPA Containing Non-Navigable Streams: 1,680,948

State: Iowa 

Population Served By SWPA Containing Non-Navigable Streams: 667,428

State: Missouri 

Population Served By SWPA Containing Non-Navigable Streams: 2,498,142

State: Kentucky 

Population Served By SWPA Containing Non-Navigable Streams: 3,282,980

State: Tennessee 

Population Served By SWPA Containing Non-Navigable Streams: 3,572,494

State: Arkansas 

Population Served By SWPA Containing Non-Navigable Streams: 941,225

State: Mississippi 

Population Served By SWPA Containing Non-Navigable Streams: 110,141

 

318 EPA, “Analysis of the Surface Drinking Water Provided By Intermittent, Ephemeral, and Headwater Streams in

the U.S.” July 2009. Available at http://water.epa.gov/lawsregs/

guidance/wetlands/upload/2009_12_28_wetlands_science_surface_drinking_water_surface_drinking_water_res

ults_state.pdf

319 Id.
Clean Water Rule Response to Comments – Topic 8: Tributaries

296

State: Louisiana 

Population Served By SWPA Containing Non-Navigable Streams: 1,886,783

State: TOTAL 

Population Served By SWPA Containing Non-Navigable Streams: 16,101,600

(p. 1, 2-6)

Agency Response: The agencies agree with the commenter that ephemeral and 

intermittent stream provide important functions that support the chemical, physical 

and biological integrity of downstream waters. The final rule, like the proposed rule, 

establishes categorical jurisdiction over all waters, including intermittent and 

ephemeral waters that meet the definition of “tributary” and are not excluded in 

paragraph (b). Many of these waters are headwater streams. See summary for 

section 8.1.1. In making this determination, the agencies relied not only on the 

science, but also on their technical expertise and practical experience in 

implementing the CWA during a period of over 40 years. In addition, the agencies 

are guided, in part, by the compelling need for clearer, more consistent and easily 

implementable standards to govern administration of the CWA, including brighter 

lines where feasible and appropriate.

Audubon California et al. (Doc. #15200)

8.72 1. The rule appropriately provides categorical protection to all tributaries, including 

perennial, intermittent and ephemeral streams. We cannot emphasize enough the 

importance of protecting intermittent and ephemeral streams through this rule-making. 

Nearly two-thirds of California’s stream miles do not flow year-round, but they remain 

critical resources for water supply, water quality, recreation, habitat and aquatic species. 

The current 3-year drought has caused even more areas to lose stream flow, and 

increasing temperatures are also affecting the amount of water in our waterways and the 

seasons in which flow can be found.

A strong example of the impact of tributaries on traditional navigable waters is found in 

the state’s Gold Rush legacy of mercury pollution. California’s State Water Resources 

Control Board identifies 80 reservoirs that are contaminated with mercury. The rivers that 

drain the watershed below each reservoir are also impaired. Mercury is a neurotoxin, 

affecting the brain and central nervous system, as well as the immune system, kidneys 

and heart. Children and pregnant women are most affected, and the state has spent 

millions developing and posting warning signs in the hundreds of miles of streams where 

fishing occurs. Clearly the headwaters feeding these reservoirs are affecting the 

“chemical, physical and biological integrity” of covered waters. (p. 2-3)

Agency Response: The agencies agree with the commenter that ephemeral and 

intermittent stream provide important functions that support the chemical, physical 

and biological integrity of downstream waters. The final rule, like the proposed rule, 

establishes categorical jurisdiction over all waters, including intermittent and 
Clean Water Rule Response to Comments – Topic 8: Tributaries

297

ephemeral waters that meet the definition of “tributary” and are not excluded in 

paragraph (b). See summary for section 8.1.1. In making this determination, the 

agencies relied not only on the science, but also on their technical expertise and 

practical experience in implementing the CWA during a period of over 40 years. In 

addition, the agencies are guided, in part, by the compelling need for clearer, more 

consistent and easily implementable standards to govern administration of the 

CWA, including brighter lines where feasible and appropriate.

Western Pennsylvania Conservancy (Doc. #15202)

8.73 Basing the proposed definition of tributary on the characteristics of direct or indirect flow 

into certain categories of jurisdictional water is consistent with the scientific body of 

evidence asserting interconnectedness of hydrologic systems as a foundational concept. 

Downstream waters are affected by their tributaries, and as such should be considered as 

a system. Waters or wetlands do not necessarily need to be adjacent to navigable waters 

to have hydrologic, biologic or chemical impacts to jurisdictional waters. These facts are 

reinforced in the major conclusions section of the synthesis of peer-reviewed literature. 

(p. 2)

Agency Response: The agencies agree with the commenter that headwater 

streams and wetlands provide important functions that support the chemical, 

physical and biological integrity of downstream waters. The final rule retains the 

phrase “contributes flow, either directly or through another water.” The final rule 

does not require that the flow be contributed either directly or through waters that 

are themselves jurisdictional. Water contributed through non-jurisdictional features 

can have the same impact on the integrity of downstream waters as water 

contributed through jurisdictional waters. This reflects scientific literature about 

the connectivity among waters discussed in the summary response of this section, 

the Technical Support Document, and the Science Report.

Center for Water Advocacy et al. (Doc. #15225)

8.74 The proposed rule affirms excepted scientific principles that the network of small and 

interconnected wetlands and headwater streams, even those that flow intermittently or 

remote from navigable water bodies, serve a critically important purpose protecting 

downstream waters by capturing flow and waterborne pollutants. (p. 4)

Agency Response: The agencies agree with the commenter that headwater 

streams and wetlands provide important functions that support the chemical, 

physical and biological integrity of downstream waters. Any water that meets the 

definition of “tributary” in the final rule is considered a “waters of the United 

States.” Although wetlands, lakes, ponds, and other features lacking a bed and 

banks and/or OHWM are no longer defined as tributaries in the Final Rule, they 

still may be considered jurisdictional waters of the U.S. either as adjacent waters or 

similarly situated waters with a significant nexus to (a)(1) through (3) waters. 

Importantly, waters, including wetlands, which are adjacent to a tributary at the 

upper limit of the channel are jurisdictional as adjacent waters. See summary 

sections for 8.1.1, 8.1.2 and 8.2. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

298

Hackensack Riverkeeper, Hudson Riverkeeper, Milwaukee Riverkeeper, New York/New Jersy

Baykeeper and Raritan Riverkeeper (Doc. #15360)

8.75 Waters of the United States Should Include Tributaries to Other Definitional Waters

It is the most basic common sense that tributaries to Waters of the United States possess a 

significant nexus - if not a continuous surface connection - to Waters of the United States, 

and are thus subject to regulation under Rapanos. The accompanying SAB Report 

supports common sense with scientific data.

Per the SAB Report, tributary waterbodies - including wetlands, low order streams, 

seasonal bodies and ephemeral bodies possess a significant nexus to bodies that are 

waters of the United States in their own right, and are thus subject to the act. "All 

tributary streams, including perennial, intermittent, and ephemeral streams, are 

physically, chemically, and biologically connected to downstream rivers via channels and 

associated alluvial deposits where water and other materials are concentrated, mixed, 

transformed, and transported. Headwater streams (headwaters) are the most abundant 

stream type in most river networks and supply most of the water in rivers. In addition to 

water, streams transport sediment, wood, organic matter, nutrients, chemical 

contaminants, and many of the organisms found in rivers." SAB Report at 1.2

Consequently, the definition of Waters of the United States should include,

6. Tributaries that contribute flow to above listed waters (p. 10)

Agency Response: The agencies agree with the commenter that headwater 

streams and wetlands provide important functions that support the chemical, 

physical and biological integrity of downstream waters. See summary response for 

section 8.1.1. The final rule, like the proposed rule, establishes categorical 

jurisdiction over all waters that meet the definition of “tributary” and that are not 

excluded in paragraph (b). Ephemeral and headwater streams with sufficient flow 

to create the physical characteristics of bed and banks and an OHWM meet the 

definition of tributary, and are thus considered waters of the United States.

Sierra Club, Cumberland Chapter (Doc. #15466)

8.76 We offer the following basis for our support for the proposed rulemaking...

2. Over 3.2 million people in Kentucky receive their drinking water from public 

drinking water systems that rely at least in part on intermittent, ephemeral, or 

headwater streams, and the proposed rulemaking will make source water protection 

more efficient and more effective. 

We have attached to this letter a map showing the "Percentage of Surface Drinking Water 

from Intermittent, Ephemeral, and Headwater Streams in Kentucky," found on the 

USEPA web page on WOTUS. Based upon this Federal Safe Drinking Water 

Information System 4th Quarter 2006 data, in Kentucky there are 15,065 total miles of 

streams that provide water for surface water intakes supplying public drinking water 

systems within the mapped Source Protection Areas (SPA). An SPA is an area upstream 

from a drinking water source or intake that contributes surface water flow to the drinking 

water intake during a 24-hour period. Of that total stream miles, 8,185 miles, of 54%, are 

intermittent, ephemeral, or headwater streams. Over 3.2 million people in Kentucky 
Clean Water Rule Response to Comments – Topic 8: Tributaries

299

receive drinking water from public drinking water systems that rely at least in part on 

intermittent, ephemeral, or headwater streams.

... (p. 2-3)

Agency Response: The agencies agree with the commenter that ephemeral and 

intermittent stream not only provide important functions that support the chemical, 

physical and biological integrity of downstream waters, but serve as valuable 

drinking waters sources. The final rule, like the proposed rule, establishes 

categorical jurisdiction over all waters, including intermittent and ephemeral 

stream that meet the definition of “tributary” and are not excluded in paragraph 

(b). In making this determination, the agencies relied not only on the science, but 

also on their technical expertise and practical experience in implementing the CWA 

during a period of over 40 years. In addition, the agencies are guided, in part, by 

the compelling need for clearer, more consistent and easily implementable 

standards to govern administration of the CWA, including brighter lines where 

feasible and appropriate

Wisconsin Wetlands Association (Doc. #15629)

8.77 The rule establishes “the contribution of flow, either directly or through another water, to 

a water identified in paragraphs (s)(1) through (4)” as the defining characteristic of a 

tributary, and provides that this applies to streams, wetlands, and other source waters. We 

support this approach, and encourage you to modify the first sentence of this definition to 

clarify that contribution of flow, rather than the physical presence of a bed, bank, and 

OHWM must be present to satisfy the definition of tributary.

...

In Wisconsin, many tributary streams and most headwater wetlands will not have a bed, 

bank, or OHWM. For this reason, we suggest modifying the definition to clarify that 

these features are reliable indicators of the presence of a tributary stream, but need not be 

present if other physical evidence of the contribution of flow is visible. (p. 2)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters.

The agencies analyzed the Science Report, SAB comments, and other scientific 

literature to determine which tributaries to traditional navigable waters, interstate 

waters, or the territorial seas have a significant nexus to constitute “waters of the 

United States” under the Act such that it is reasonable to assert CWA jurisdiction 

over them by rule. The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. In the Final Rule, by 

definition tributaries must have bed and banks and an OHWM, as well as 

contribute flow to an (a)(1) through (3) water. Lakes, wetlands, and other features 

lacking these physical characteristics are no longer defined as tributaries but may 

be considered jurisdictional waters of the U.S. as adjacent waters or similarly 

situated waters with a significant nexus to (a)(1) through (3) waters. See also the 

summary response for Section 8.2. 
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Friends of the Rappahannock (Doc. #15864)

8.78 B. The Proposed Rule Will Protect Water Quality in the Chesapeake Bay

...The Rappahannock River and its tributaries are among the many Rivers and streams in 

the Chesapeake Bay that provides drinking water, wildlife habitat, and recreational 

opportunities to its residents and visitors.

Our River is over 190 miles long320 stretching from Chester Gap in the Blue Ridge 

Mountains all the way to the Chesapeake Bay, which makes it the longest free flowing 

River in the Chesapeake Bay. The watershed includes hundreds of small intermittent and 

ephemeral streams as well as both tidal and non-tidal wetlands which are essential to 

providing drinking water, habitat, and flood protections.

These waters are actually small ecosystems that are paramount to the health and function 

of the larger watershed. FOR works tirelessly to protect and restore stream banks, 

shorelines, and wetlands throughout the watershed on both public and private land to 

protect and improve water quality. These efforts need to be complimented by strong and 

clear protections for the waters in our watershed. 

C. The Proposed Rule Will Protect Sensitive Waters in the Chesapeake Bay Watershed

...Both the main stem of the Rappahannock River and its largest tributary- the Rapidan 

River, are positioned in the foothill of the Blue Ridge and Shenandoah Mountains. Land 

use in these regions range from forest and farms, to new development. Every year, FOR 

works with local students and conservation organizations to protect the sensitive 

headwater reaches of the Rappahannock watershed through stream restoration, riparian 

plantings, and livestock fencing. These practices are an essential part of reaching larger 

Total Maximum Daily Load (TMDL) and Bay Program goals for water quality. 

Protection of these sensitive headwaters is critical to safeguarding water quality and 

wildlife throughout the Rappahannock Watershed, Commonwealth of Virginia, and the 

Chesapeake Bay watershed. (p. 3-4)

Agency Response: The Agency appreciates your comments regarding the affect of 

the Rappahannock River and its tributaries on the Chesapeake Bay. See summary 

response for “Relevance of Flow Regime” above, particularly subsections on 

jurisdiction over intermittent and ephemeral waters.

Regulatory Environmental Group for Missouri (Doc. #16337.1)

8.79 The Proposed Rule sets neither time limits nor geographic limits on the contributory 

flow. It is per se jurisdictional. By claiming tributaries as jurisdictional; the Proposed 

Rule eliminates the consideration of site-specific conditions which violates both the 

Rapanos plurality decision of Justice Scalia and the concurrence opinion of Justice 

Kennedy. The concurring opinion relied on a “significant nexus” but, as noted, further 

insisted that mere hydrologic connection does not bestow ecological significance to 

certain waters. (p. 6)

 

320 U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data. The National Map, 

accessed April 1, 2011.
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Agency Response: Section I of the Technical Support Document discusses the 

legal basis of the final rule, including consistency with the statute and Supreme 

Court decisions. The agencies’ conclusions that certain categories of waters are 

jurisdictional are not based on an “any connection” theory; instead they are based 

on careful examinations of the science and the law to conclude that particular 

categories of waters significantly affect the chemical, physical, and biological 

integrity of a traditional navigable water, interstate water, or the territorial seas. 

Section VII of the Technical Support Document discusses the science supporting the 

agencies’ conclusion that all waters that meet the definition of “tributary” and that 

are not excluded in paragraph (b), have a significant nexus either individually or in 

the aggregate with traditional navigable waters, interstate waters, and the territorial 

seas.

Charles River Conservancy et al. (Doc. #16453)

8.80 We support the Agencies’ proposal to define all tributaries as “waters of the United 

States,” including headwaters and small streams that may only flow seasonally.

These streams are also critical habitat for fish and other aquatic species. Headwater and 

seasonal streams also feed the drinking water sources of 117 million Americans.

The Agencies’ commonsense proposal is based on the best scientific understanding of 

how streams and wetlands affect downstream water quality. The public benefits of the 

rule – in the form of flood protection, filtering pollution, providing wildlife habitat, 

supporting outdoor recreation and recharging groundwater – far outweigh the costs. 

When finalized, this rule will provide the regulatory assurance that has been absent for 

over a decade, eliminate permit confusion and delay, and better protect the critical water 

resources on which our communities depend. (p. 2)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters.

Defenders of Wildlife and Patagonia Area Resource Alliance (Doc. #16394)

8.81 Defenders strongly supports the inclusion of “tributaries” to waters identified in (s)(1)-

(s)(4) as waters of the U.S. However, as noted below and in Earthjustice’s comments, the 

definitions in proposed subsections (s)(5) and (u)(5) are too limited.

The science is overwhelming that tributaries significantly affect downstream waters, and 

that to protect a downstream navigable and/or interstate water, its tributaries must also be 

protected. As the agencies acknowledge, “[t]he great majority of tributaries are 

headwaters streams, and whether they are perennial, intermittent, or ephemeral, they play 

an important role in the transport of water, sediments, organic matter, nutrients, and 

organisms to downstream environments.” 79 Fed. Reg. at 22201; see EPA Connectivity

Report at 1-3 (“All tributary streams, including perennial, intermittent, and ephemeral 

streams, are physically, chemically, and biologically connected to downstream rivers via 

channels and associated alluvial deposits where water and other materials are 

concentrated, mixed, transformed, and transported.”). Similarly, the SAB concluded, 

“[t]here is strong scientific evidence to support the EPA’s proposal to include all 

tributaries within the jurisdiction of the Clean Water Act.” SAB letter at 2; see also SAB 

Review at 3 (“Strong scientific support has been provided” for the agencies’ conclusion 
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302

that “all tributary streams are physically, chemically, and biologically connected to 

downstream waters” and “related findings”).

The inclusion of intermittent and ephemeral tributaries is particularly critical to protect 

downstream waters. See 79 Fed. Reg. at 22202 (“The flow in the tributary may be 

ephemeral, intermittent, or perennial, but the tributary must drain, or be part of a network 

of tributaries that drain, into an [s](1) through [s](4) water under today’s proposed rule.”). 

According to EPA’s data, 59% of the streams in the lower 48 states and Hawai’i are 

intermittent or ephemeral. EPA Office of Research and Development, “The Ecological 

and Hydrological Significance of Ephemeral and Intermittent Streams in the Arid and 

Semi-arid American Southwest,” (2008), at 5 (hereinafter “EPA 2008”).321 In the desert 

Southwest, the number and importance of ephemeral and intermittent tributaries to 

hydrologic systems is even greater: 81% of all streams in the six Southwestern states are 

ephemeral or intermittent, including 94% of Arizona’s streams and nearly two-thirds of 

California’s streams. Id. at 5, 48. Thus, allowing degradation of ephemeral or intermittent 

streams – by failing to protect them under the Clean Water Act as waters of the U.S. –

would detrimentally affect most of the Southwest’s and California’s watersheds. EPA 

2008 at 48.

Ephemeral and intermittent tributaries play an important part in the area’s ecology and 

water supply by flowing above ground into perennial waters of the U.S., charging 

aquifers, or otherwise connecting underground to perennial waters of the U.S. As EPA 

explained, the water in these streams provides critical hydrologic connections to all other 

waters in the watershed:

Ephemeral streams are unique in that they lack permanent flow except in response 

to rainfall events. Intermittent streams flow continuously only in places where it 

receives water from a ground-water source or from seasonal runoff. Nevertheless, 

they perform the same critical hydrologic functions as perennial streams: they 

move water, sediment, nutrients, and debris through the stream network and 

provide connectivity within the watershed.

Id. at 13; id. at 72 (“We believe that the information presented in this report shows that 

ephemeral and intermittent streams in the arid and semi-arid Southwestern U.S. are 

ecologically and hydrologically connected to downstream waters, and have a significant 

effect on the chemical, physical, and biological integrity of those waters.”). Similarly, 

one member of the SAB explained, “[i]n many landscapes, especially the arid and semiarid and western US, these intermittent or ephemeral connections are critical, providing 

much of the connectivity that facilitates that transport of mass, energy, and organisms to 

downgradient waters (e.g., Izbicki, 2007).” “Compilation of Preliminary Comments from 

Individual Panel Members on the Scientific and Technical Basis of the Proposed Rule 

Titled ‘Definition of Waters of the United States Under the Clean Water Act,’” (as of 

August 14, 2014) (hereinafter “Member Comments”) Dr. Mark Rains, at 71, attached as 

Exh. B; see also EPA 2008 at 64 (“Ephemeral and intermittent streams and tributaries 

provide a wide range of functions that are critical to the health and stability of arid and 

 

321 Also available at http://www.epa.gov/esd/landsci/pdf/EPHEMERAL_STREAMS_REPORT_Final_508-

Kepner.pdf (last visited Sept. 23, 2014).
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semi-arid watersheds and ecosystems in the American Southwest. Most importantly, they 

provide hydrologic connectivity within a basin, linking ephemeral, intermittent, and 

perennial stream segments, thereby facilitating the movement of water, sediment, 

nutrients, debris, fish, wildlife, and plant propagules throughout the watershed.”).

According to the California Department of Fish and Wildlife, ephemeral streams in 

dryland watersheds provide the same ecosystem services as perennial streams, largely 

determining the ecological health of the entire watershed. These desert streams and 

washes support biological communities that do not depend on mature woodland or stream 

corridor conditions and are the predominant fluvial forms in arid and semiarid 

environments, supporting high biodiversity and habitat values relative to drier uplands. 

For example, in the Mojave Desert, these ephemeral streams provide important habitat 

for threatened Desert tortoise, Desert bighorn sheep, and a myriad of migratory birds. 

Ephemeral streams provide ecosystem services such as: watershed and landscape 

hydrologic connections; water supply protection and water quality filtering; wildlife 

habitat and movement/migration corridors; groundwater recharge and discharge; 

sediment transport, storage and deposition; nutrient cycling and movement, and 

vegetation community support. Letter to California Energy Commission from the 

California Department of Fish and Wildlife on the subject of Hidden Hills Solar Electric 

Generating System, State Waters Compensatory Mitigation (February 14, 2014).

The riparian areas around ephemeral and intermittent streams “generally support the 

greatest concentrations of wildlife, providing the primary habitat, predator protection, 

breeding and nesting sites, shade, movement corridors, migration stopover sites, and food 

sources.” EPA 2008 at 47. “In the arid Southwest, about 80 percent of all animals use 

riparian resources and habitats at some life stage, and more than 50 percent of breeding 

bird species nest chiefly in riparian habitats (Krueper 1993).” Id.

EPA’s 2008 Report on Ephemeral and Intermittent Streams in the Southwest highlighted 

some of the many wildlife species that depend on the habitats created by ephemeral and 

intermittent streams for various life stages. For example, in southern Arizona and 

adjacent Sonora, Mexico, “[m]any reptiles and amphibians depend on permanent springs, 

seeps, and ephemeral streams for their survival. Although these species are widely 

distributed throughout the region, their narrow ecological distributions and low densities 

make them extremely vulnerable to habitat degradation.” Id. at 55. These impacts include 

groundwater pumping and pollution. Id. In Saguaro National Park near Tucson, Arizona, 

lowland leopard frogs depend on bedrock pools in ephemeral streams for breeding 

habitat. Id. The canyon tree frog uses the temporary pools during summer rains for 

breeding and is found along temporary, intermittent, and permanent streams, springs, and 

tinajas in rocky desert canyons in much of the Southwest. Id. at 56. Similarly, many 

species of birds, mammals, and invertebrates depend on ephemeral and intermittent 

streams, in some cases more than perennial streams. Id. at 57-62. EPA cited one study 

that compiled a list of 55 mammals that use riparian areas in any way for breeding, 

foraging, cover or migration, and noted that only a few mammals in Arizona were truly 

tied to aquatic habitats found in perennial streams. Id. at 60. Moreover, many species of 

fish can be found in isolated perennial pools in otherwise ephemeral or intermittent 

streams. Id. at 63. Even where ephemeral streams cannot support fish, they help fish 
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indirectly by supplying the required nutrients and other materials to the perennial 

segments. Id. at 64.

The importance of protecting the ephemeral and intermittent stream connections is 

illustrated in the mountains surrounding the town of Patagonia, Arizona. Tailings piles 

from more than 100 abandoned hard-rock mines have contaminated ephemeral and 

intermittent tributaries of Harshaw Creek and Sonoita Creek. For example, the Trench 

Mine filled the head of Alum Gulch, an intermittent tributary to Sonoita Creek, with mine 

tailings. Flow in upper Alum Gulch carries measurable quantities of cadmium, copper, 

and zinc and has excessively low pH. During heavy rain events in 2014, this 

contaminated water flowed through Alum Gulch directly into Sonoita Creek, a perennial 

water. This stretch of Sonoita Creek is the site of proposed critical habitat for the 

threatened western yellow-billed cuckoo. Other federally listed species dependent on 

Sonoita Creek include the Huachuca water umbel, Gila Topminnow, Chiricahua leopard 

frog, and northern Mexican gartersnake. Sonoita Creek eventually flows through Lake 

Patagonia, where many people fish and recreate, Sonoita Creek state natural area, and 

then ultimately into the Santa Cruz River.

Outside of the arid Southwest and California, headwater streams, which are not always 

perennial, are also critical for fish and wildlife. For example, headwater streams provide 

critical habitat for fish species that migrate between marine and small stream 

environments, such as Pacific and Atlantic salmon, and American eels. EPA Connectivity 

Report at 1-8. Similarly, many fishes in prairie streams swim upstream to tributaries to 

lay their eggs, which develop as they float downstream. EPA Connectivity Report at 1-8. 

Small streams also provide “refuge habitat for riverine organisms seeking protection from 

temperature extremes, flow extremes, low dissolved oxygen, high sediment levels, or the 

presence of predators, parasites, and competitors.” Id. (p. 3-6)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsection on jurisdiction over intermittent and ephemeral waters. The 

agencies analyzed the Science Report, SAB comments, and other scientific literature 

to determine which tributaries to traditional navigable waters, interstate waters, or 

the territorial seas have a significant nexus to constitute “waters of the United 

States” under the Act such that it is reasonable to assert CWA jurisdiction over 

them by rule. As discussed above, the rule’s definition of “tributary” requires bed 

and banks and OHWM as physical indicators of flow, which as a result does not 

include all waters considered tributary in the scientific literature. The agencies

conclude tributaries as defined have a significant impact on the chemical, physical, 

and biological integrity of waters into which they eventually flow— for CWA 

purposes, traditional navigable waters, interstate waters, and the territorial seas. 

The great majority of covered tributaries are headwater streams, and whether they 

are perennial, intermittent, or ephemeral, they play an important role in the 

transport of water, sediments, organic matter, nutrients, and organisms to 

downstream waters. Covered tributaries serve to store water, thereby reducing 

flooding; provide biogeochemical functions that help maintain water quality; trap 

and transport sediments; transport, store and modify pollutants; provide habitat for 

plants and animals; and sustain the biological productivity of downstream rivers, 

lakes, and estuaries. Such waters have these significant effects whether they are 
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natural, modified, or constructed, as discussed below. For further discussion, see 

Final Rule Preamble and the Technical Support Document.

Michigan United Conservation Clubs (Doc. #16395)

8.82 C. The Proposed Rule Will Protect Sensitive Waters in the Michigan and the Great Lakes

One of the most important aspects of the proposed rule is its protection of intermittent 

and ephemeral streams, which is important to Michigan anglers and all coldwater fishing 

in Michigan. Protection of these sensitive headwaters is critical to safeguarding water 

quality, fisheries and wildlife habitat throughout the Great Lakes region. While some of 

these areas are already protected by Michigan’s state statute, there are areas even in 

Michigan still under the USACE administration that would still benefit from clarification. 

But more importantly, this proposed rule is bringing other Great Lakes states up to 

Michigan’s standards of protection and providing consistency of protection. (p. 2)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsection on jurisdiction over intermittent and ephemeral waters.

Waterkeeper Alliance et al. (Doc. #16413)

8.83 ... the agency must clarify in the definition of tributary and/or the Preamble what it 

intends when it states that in order to be defined as a tributary, the tributary must 

contribute "flow, either directly or through another water, to a water identified in 

paragraphs (l)(1)(i) through (iv)." It is unclear from this language whether the agencies 

will require "another water" to also be a defined "water of the United States." We urge 

the agencies to clarify that they mean any body of water whether it is a defined "water of 

the United States or not." This would be consistent with the Connectivity Report and the 

law. While this interpretation is implied by the language in footnote 3 of the Proposed 

Definition, it requires further clarification.322

Jurisdictional limitations for tributaries under existing definition arose nearly exclusively 

from the agencies' 2003 and 2008 Guidance. This Guidance placed additional 

requirements on the agencies' ability to assert CWA jurisdiction over tributaries that were 

not required or supported by law and science. However, even under the 2008 Guidance, 

the agencies claimed jurisdiction over non-navigable tributaries that met the "relatively 

permanent" or the "significant nexus" test,323 Although we disagree with the 

interpretation of the "relatively permanent" and "significant nexus" tests reflected in the 

2008 Guidance for the reasons set forth in our comments,324 the 2008 Guidance document 

illustrates that the agencies believed that tributaries could be protected under both of 

these Rapanos jurisdictional tests. Accordingly, it is difficult to understand why the 

agencies are only applying the "significant nexus" test to determine the extent of 

 

322 See 79 Fed.Reg. at 22191, fn. 3.

323 Jurisdiction Following Rapanos v. United States and Carabell v. United States, supra note 49.

324 In support of our comments, we hereby incorporate by reference the comments submitted by national 

environmental organizations on the 2008 Guidance, which are a part of the official public docket in 2011 at 

http://www.regulations.gov/#!documentDetail;D-EPA-HQ-QW--0282-0001 at HQ-QW-2002-00S0-1674.
Clean Water Rule Response to Comments – Topic 8: Tributaries

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jurisdiction over tributaries in the Proposed Definition and Preamble.325 We strongly 

object to the agencies' approach - the EPA and the Corps should be asserting jurisdiction 

over all tributaries covered under the existing regulations, all tributaries that meet the 

"relatively permanent" test and all tributaries that meet the "significant nexus" test. There 

is simply no valid legal or scientific reason to do otherwise.

Although we believe that the EPA and the Corps should not rely solely on the "significant 

nexus" analysis as the agencies' basis for including tributaries in the definition, we do 

agree that the inclusion of ephemeral, intermittent and perennial tributaries, as "waters of 

the United States" is legally and scientifically sound and is supported by the EPA's 

"significant nexus" analysis, the Connectivity Report, and the SAB Member Comments. 

We also believe that wetlands, lakes and ponds should be included as tributaries based on 

the findings of the Connectivity Report and many individual SAB Member 

Comments."326

In addition to the Connectivity Report and SAB Report, numerous scientific reports and 

government documents from across the country illustrate the importance of protecting 

these waters. A recent report produced by Trout Unlimited, using USGS National 

Hydrography Dataset, documents the abundance and importance of intermittent and 

headwater streams across the country showing, for example, that 48 percent of stream 

miles with native trout historical range are classified as intermittent or ephemeral, and 58 

percent of stream miles are in headwater streams.327 The Trout Unlimited Report also 

states that 64 percent of stream miles with salmon/steelhead range are classified as 

intermittent or ephemeral, and 57 percent of stream miles are in headwater streams. In 

North Carolina, research conducted by the North Carolina Department of Natural 

Resources - Division of Water Quality, concluded that:

In summary, staff of the Division of Water Quality have been I conducting 

intensive research on headwater streams and headwater wetlands across the state 

for the past several years. Headwater streams are very common and provide 

significant I benefits to downstream water quality and aquatic life. Intermittent 

streams have significant aquatic life even though their flow is not constant 

throughout the year. Headwater wetlands are often associated with these streams 

and provide important water quality filtration to protect downstream water quality 

as' well as significant aquatic life habitat. Therefore based on this on-going 

research, the Division of Water Quality believes that protection of these 

 

325 Proposed Definition, 79 Fed.Reg. at 22189, 22201 ("The agencies emphasize that the categorical finding of 

jurisdiction for tributaries and adjacent waters was not based on the mere connection of a water body to downstream 

waters, but rather a determination that the nexus, alone or in combination with similarly situated waters in the 

region, is significant based on data, science, the CWA, and caselaw."].

326 See e.g., Connectivity Report supra note 3, at 1-8 (nutrient removal and cycling); Member Comments, supra note 

72 Rosi-Marshall at 81 and Sullivan at 85.

327 Rising to the Challenge - How Anglers Can Respond to Threats to Fishing in America, available at: 

http://www.tu.org/sites/default/files/TU_Rising_to_the_Challenge_web.pdf.
Clean Water Rule Response to Comments – Topic 8: Tributaries

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headwater streams and wetlands is essential to protect downstream water 

quality.”328 (p. 28-30)

Agency Response: The final rule, like the proposed rule, establishes categorical 

jurisdiction over all waters that meet the definition of “tributary.” Section I of the 

Technical Support Document discusses the legal basis of the final rule, including 

consistency with the statute and Supreme Court decisions and utilization of the 

significant nexus standard. Section VII of the Technical Support Document 

discusses the science supporting the agencies' conclusion that all waters that meet 

the definition of "tributary" and that are not excluded in paragraph (b), have a 

significant nexus either individually or in the aggregate with traditional navigable 

waters, interstate waters, and the territorial seas. A great majority of the tributaries 

covered by the rule are headwater streams. The final rule’s definition of “tributary” 

retains many elements from the proposed rule, but reflects public comments in 

several important ways. In particular, the final rule emphasizes the importance of 

flow. The rule definition of “tributary” requires that flow much be of sufficient 

volume, frequency, and durations to create physical characteristics of bed and 

banks and an OHWM. As a result, wetlands, lakes, ponds, and other features 

lacking a bed and banks and/or OHWM are no longer defined as tributaries in the 

Final Rule. However, they still may be considered jurisdictional waters of the U.S. 

either as adjacent waters or similarly situated waters with a significant nexus to 

(a)(1) through (3) waters. Importantly, waters, including wetlands, which are 

adjacent to a tributary at the upper limit of the channel are jurisdictional as 

adjacent waters. See Preamble sections H and G for further discussion. Further, the 

Final Rule clarifies that flow can be contributed through waters that are not 

themselves jurisdictional. Waters contributed through non-jurisdictional features 

can have the same impact on the integrity of downstream waters as water 

contributed through jurisdictional waters. The agencies maintain that some waters 

may pass through non-jurisdictional waters, such as excluded ditches, but will still 

be classified as tributaries both upstream and downstream of the non-jurisdictional 

feature.

Wyoming Outdoor Council (Doc. #16528)

8.84 One important recognition in the proposed rule is that "headwaters" streams can and often 

do supply the most water to downstream streams and are the most abundant source of 

water in many systems (via perennial, intermittent, and ephemeral flows). 79 Fed. Reg. at 

22197, 2220 I. Tributaries are the dominant source of water in most rivers, even if they 

are seasonally dry, rather than water being contributed principally through direct 

precipitation or groundwater input. Id. at 22205. These headwaters tributaries play an 

important role in the transport of water, sediments, organic matter, nutrients, and 

organisms downstream and also serve to store water, which can reduce flooding and 

reduce pollution downstream. Headwaters have these impacts even if they are located at 

 

328 Memo from John Dorney, Wetlands Program Development Unit, NC DWQ. April 5, 2006. Background 

information on the water quality and aquatic life values of headwater streams and headwater wetlands, available at 

http://aswm.org/pdf_lib/cover_letter_and_summary_nc.pdf.
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some distance from an (a)(1)-(3) water. Id. at 22206. Headwaters are recognized as 

"essential components" of the tributary network. Id. Moreover, it is recognized that the 

aggregate impact of a number of headwaters streams and tributaries on downstream 

chemical, physical, and biological integrity must be considered-the aggregate impact can 

be very substantial. Id. at 22195.

Given the strength of these impacts on downstream waters it is clear tributaries have a 

significant (not speculative or insubstantial) impact on downstream chemical, physical, 

and biological integrity, and thus defining tributaries as waters of the United States by 

rule is warranted. 79 Fed. Reg. at 22195-96. That is, they clearly have a significant nexus 

with downstream waters. (p. 2-3)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsection on jurisdiction over intermittent and ephemeral waters.

Tennessee Clean Water Network et al. (Doc. #16537)

8.85 Categorical protection of all tributaries, including headwaters is essential, because 

tributaries connect the river network and provide vital ecosystem functions. The 

importance of headwater streams to the health of larger, navigable rivers like the 

Tennessee and Mississippi Rivers cannot be understated. 30% of Tennessee's streams are 

intermittent or ephemeral. Intermittent and ephemeral streams have significant influence 

upon public drinking water sources in Tennessee with over 3.5 million residents getting 

their drinking water from these streams.

Protecting tributaries and headwater streams is also vital to the fishing industry of our 

state and the defense of threatened and endangered species. The vast majority of 

Tennessee's aquatic biological diversity, Including state and federally threatened and 

endangered species, occurs in non-navigable streams as traditionally protected by the 

Act.329 Also, the majority of Tennessee's trout streams are not traditionally navigable 

streams. Sport fishing contributed more than a billion dollars to the Tennessee economy. 

This popular activity is dependent on clean water and healthy habitat

The vital role of headwaters in the health of larger rivers and in human health and 

recreation makes categorical protection of tributaries essential. The science regarding 

connectivity and essential ecosystem services is clear. Case-by-case jurisdictional 

determinations are no longer workable and cannot provide the level of protection needed 

for headwaters and other tributaries. (p. 2)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsection on jurisdiction over intermittent and ephemeral waters.

Audubon Society of Greater Denver (Doc. #16934)

8.86 1. Protection of headwater, intermittent and ephemeral streams.

 

329 Tennessee Wildlife Resources Agency, Comments on "Advance Notice of Proposed Rulemaking on the Clean 

Water Act Regulatory Definition of 'Waters of the United States," Docket ill OW-2002-00S0 at p- 2-3 (Feb. 26, 

2003).
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In Colorado, as in many other states, some streams contain water only in spring and early 

summer and run dry later in the year. When running, they obviously connect to 

downstream waters; when dry, they still contribute to water quality downstream through 

migration of eroded materials, groundwater pathways and movement of biota. Thus they 

can still strongly influence the integrity of downstream waters. Due to this connectivity 

they should receive protection under the Clean Water Act, and the proposed Rule will 

help to ensure this. (p. 1)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsection on jurisdiction over intermittent and ephemeral waters.

Warm Springs Watershed Association (Doc. #18019)

8.87 As a watershed organization caring for a headwater tributary, we believe that defining 

intermittent, ephemeral, and headwater streams as “Waters of the U.S.” provides 

important clarification to the Clean Water Act’s jurisdiction.

The Supreme Court opined that the EPA and Army Corps of Engineers must demonstrate 

a significant nexus between, among others, headwaters and downstream waters. EPA’s 

assessment, titled Connectivity of Streams and Wetlands to Downstream Waters, presents 

a review and synthesis of more than 1,000 pieces of scientific literature. This assessment 

was reviewed by the independent Science Advisory Board, or SAB...

The proposed rule will clarify the Clean Water Act’s jurisdiction, reduce uncertainty, and 

protect drinking water for millions of Americans whose source water originates in the 

West Virginia headwaters— including those who reside in West Virginia... (p. 1)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsection on jurisdiction over intermittent and ephemeral waters.

Upper Mississippi, Illinois, & Missouri Rivers Association (Doc. #19563)

8.88 The agencies assert jurisdiction too broadly over tributaries.

The Proposed Rule classifies tributaries as jurisdictional by rule and, for the first time, 

defines the term. The agencies' conclusion that all tributaries have a significant nexus to 

jurisdictional waters without any case-specific review to identify factor s of significance 

exceeds the intended limits of Rapanos. Thus both the proposed assertion of jurisdiction 

over all tributaries without any analysis, as well as the definition of the term "tributary," 

are excessively broad.

"Tributary" is defined in the Proposed Rule as "a water physically characterized by the 

presence of a bed and banks and ordinary high water mark....which contributes flow, 

either directly or through another [jurisdictional water]," and, additionally, "wetlands, 

lakes, and ponds are tributaries (even if they lack a bed and bank s or ordinary high water 

mark) if they contribute flow."330 The definition contains no reference to the volume or 

frequency of such flow, creating uncertainty and the potential for jurisdictional overreaching. The definition could encompass impermanent waters that lack consistent flow, 

 

330 Merriam-Webster Online Dictionary , http: //www.merriam-webster.com/dictionary/adjacent. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

310

clearly deviating from the standard articulated by Justice Scalia in the Rapanos plurality 

opinion331 and, at the least, raising questions under the "significant nexus" test. (p. 9)

Agency Response: See summary response for "Relevance of Flow Regime" above, 

particularly subsections on jurisdiction over intermittent and ephemeral waters, the 

legality of asserting jurisdiction over ephemeral waters and the requirement of 

"contribute flow." Section I of the Technical Support Document discusses the legal 

basis of the final rule, including consistency with the statute and Supreme Court 

decisions. Section VII of the Technical Support Document discusses the science 

supporting the agencies' conclusion that all waters that meet the definition of 

"tributary" and that are not excluded in paragraph (b), have a significant nexus 

either individually or in the aggregate with traditional navigable waters, interstate 

waters, and the territorial seas.

Society for Freshwater Science (Doc. #11783)

8.89 We support the following general changes as both scientifically defensible and 

appropriate distinctions in the rule. First, the recognition that streams, regardless of flow 

status (ephemeral to perennial), strongly influence downstream physical, chemical, and 

biological integrity ("integrity"). This is consistent with the science developed by our 

members as detailed in the USEPA 2013 document showing the importance of headwater 

streams to the health of downstream waters. With protections extended to all tributaries, 

including ephemeral, the rule avoids the death by a thousand cuts of downstream waters 

when headwaters are not adequately protected. To be clear, this extends to tributaries 

above geomorphic barriers or process domains that may interrupt surface flow at times, 

but do not interrupt the longitudinal connectivity in time or in subsurface flows... (p. 2)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsection on jurisdiction over intermittent and ephemeral waters.

Under the final rule, a water that otherwise qualifies as a tributary under this 

definition does not lose its status as a tributary if, for any length, there are one or 

more man-made breaks (such as bridges, culverts, pipes, or dams), or one or more 

natural breaks (such as wetlands at the head of or along the run of a stream, debris 

piles, boulder fields, or a stream that flows underground) so long as a bed and banks 

and an ordinary high water mark can be identified upstream of the break.” 

Consortium of Aquatic Scientific Societies (Doc. #14802)

8.90 We strongly support inclusion of headwater streams, including intermittent or temporary 

streams that do not have perennial flow. There is now ample scientific evidence (much of 

it cited in the proposed rule) that there are strong and varied physical, chemical, and 

biological connections between headwater streams, whether they have perennial flow or 

not, and downstream navigable or interstate waters. This clearly satisfies the requirement 

for “significant nexus”. Furthermore, the proposed use of the presence of bed, banks, and 

an ordinary high-water mark to identify stream channels that should be included seems 

 

331 79 Fed. Reg. at 22,263.
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311

both practical to apply in the field and consistent with the scientific evidence regarding 

strong connections. (p. 1)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly subsection on jurisdiction over intermittent and ephemeral waters.

United States Senate (Doc. #19655)

8.91 5) Switching attention to the proposed "waters of the US" rule, many questions have been 

raised about intermittent streams and low-lying areas on fields. Some concerned 

stakeholders believe that flow and runoff from fields may be categorized as tributaries, 

and thus regulated under the proposed rule. To this point, the proposed rule states that 

ephemeral features located on agricultural lands that do not possess a bed and bank are 

not tributaries. We believe defining the term bed and bank will significantly help resolve 

confusion as to which agricultural features can be classified as tributaries. Does the 

agency have plans to define these terms? (p. 3)

Agency Response: The preamble of the final rule defines bed and banks to mean 

the substrate and sides of a channel between which flow is confined. The banks 

constitute a break in slope between the edge of the bed and the surrounding terrain, 

and may vary from steep to gradual. For a discussion of the agencies’ response to 

comments regarding clarity for definitions, see Compendium 14.3 and associated 

summary essay and individual responses. See also the summary response for

“Relevance of Flow Regime” above. The definition of “tributary” in the final rule 

requires that flow must be of sufficient volume, frequency, and duration to create 

the physical characteristics of bed and banks and an OHWM. If a water lacks 

sufficient flow to create such characteristics, it is not considered “tributary” under 

this rule. To further emphasize this point, the final rule expressly indicates in 

paragraph (b) that ephemeral reaches that do not meet the definition of tributary 

are not “waters of the United States.”.

United States House of Representatives (Doc. #17458)

8.92 Questions from the Honorable Rep. Napolitano, (D-CA)

1. How will the proposed rule apply to western streams which are ephemeral in nature 

and which may flow only one or two times a year? Will they have to go through the 

same permitting process as [...] (p. 4)

Agency Response: See summary response for “Relevance of Flow Regime” above, 

particularly the subsection on jurisdiction over intermittent and ephemeral waters.

The final rule, like the proposed rule, establishes categorical jurisdiction over all 

waters that meet the definition of “tributary” and that are not excluded in 

paragraph (b). Ephemeral streams with sufficient flow to create the physical 

characteristics of bed and banks and an OHWM meet the definition of tributary, 

and are thus considered waters of the United States. The agencies determined that 

such streams provide important functions for downstream waters, and in 

combination with other protected tributaries in a watershed significantly affect the 

chemical, physical, and biological integrity of traditional navigable waters, 

interstate waters, and the territorial seas. However, the final rule expressly 
Clean Water Rule Response to Comments – Topic 8: Tributaries

312

indicates in paragraph (b) that ephemeral reaches that do not meet the definition of 

tributary are not waters of the United States. Section VII of the Technical Support 

Document discusses the science supporting the agencies’ conclusion. 

8.1.2. Ordinary High Water Mark (OHWM)

Agency Summary Response

Previous definitions of “waters of the United States” regulated all tributaries without 

qualification. The final rule protects only waters that have a significant effect on the integrity of 

traditional navigable waters, interstate waters, or the territorial seas. Among these waters are 

“tributaries.” The rule establishes a definition of “tributary,” and provides that all waters meeting

the definition of tributary, unless a water is excluded under paragraph (b), are “waters of the 

United States” without the need for a separate case-specific significant nexus evaluation. The 

rule defines “tributaries” as 

...a water that contributes flow, either directly or through another water (including an 

impoundment identified in paragraph (a)(4) of this section), to a water identified in 

paragraphs (a)(1) through (3) of this section that is characterized by the presence of the 

physical indicators of a bed and banks and an ordinary high water mark... 

Covered tributaries and the functions they provide, alone or in combination with other tributaries 

in the watershed, significantly affect the chemical, physical, and biological integrity of 

traditional navigable waters, interstate waters, or the territorial seas. See preamble section III.C. 

and the Technical Support Document.

Issue: Use of OHWM inappropriate/appropriate – will lead to over/under coverage of features

Many commenters were uncomfortable with the use of OHWM in the definition of tributary due 

to a history of inconsistent identification of OHWM indicators regionally and among the 

agencies’ field staff. Many commenters stated that methods for identifying the OHWM in 

ephemeral features are unreliable, confusing, and/or speculative, and highlighted questions raised 

during SAB review of the Science Report on Connectivity. Most believed that the use of 

OHWM in identifying jurisdictional tributaries will greatly increase the number of ephemeral 

features that are regulated under the CWA, compared to current practice and Rapanos Guidance.

Use of OHWM is not a new concept or practice. The OHWM is currently used to identify the 

lateral extent of jurisdictional waters of the U.S. Bed and banks and OHWM have been identified 

on the 2008 Rapanos Approved Jurisdictional Determination form as an indicator of tributary 

characteristics. The final rule does not propose a change to the existing guidance and practice of 

identifying the OHWM of streams. Instead, under the final rule the presence of an OHWM 

(along with bed and banks) will be used to identify “tributaries,” which the agencies determined

categorically to have a significant nexus to downstream waters. 

Many comments rested on the incorrect assertion that the agencies do not currently regulate 

ephemeral streams. Rather, under Rapanos Guidance, ephemeral and other streams are 

considered jurisdictional if they are a relatively permanent tributary to a traditionally navigable 

water (TNW), or a non-relatively permanent tributary with a significant nexus to a TNW. The 
Clean Water Rule Response to Comments – Topic 8: Tributaries

313

final rule will eliminate the need to identify a water as relatively-permanent, or conduct a 

significant nexus determination for each tributary; rather, the agencies have determined that 

tributaries as a class (i.e., waters meeting the final rule’s definition of “tributary”) have a 

significant nexus to downstream TNWs.

The final rule’s definition of “tributaries” includes waters with ephemeral flow where such 

ephemeral tributaries present the indicators of OHWM and bed and banks, indicating sufficient 

volume, frequency, and duration of flow to maintain these physical characteristics. The 

scientific literature supports that the view that these ephemeral tributaries have a significant 

nexus to (a)(1) through (a)(3) waters either individually or in aggregate, as discussed in the 

Science Report, which stresses that all tributaries, including ephemeral tributaries, have strong 

connections to downstream waters. Therefore, assuming ephemeral waters meet the definition 

of “tributary,” they are per-se jurisdictional under the final rule. See also the summary responses 

in Section 9 “Scientific Evidence Supporting the Rule” of the Response to Comments.

The SAB review of the Science Report on Connectivity concluded “the review and synthesis of 

the literature describing connectivity of streams to downstream waters reflects the pertinent 

literature and is well grounded in current science. The literature review provides strong scientific 

support for the conclusion that ephemeral, intermittent, and perennial streams exert a strong 

influence on the character and functioning of downstream waters and that tributary streams are 

connected to downstream waters.” In response to the SAB’s recommendation more literature 

regarding the importance of episodic connections between ephemeral and intermittent streams 

and downstream waters was added to Section B.5 and Section 3 of the Final Report. As some 

comments indicated, Walnut Gulch is a tributary to the San Pedro River and has an extensive 

data set and that has contributed greatly to the scientific understanding of the connections to and 

effects of small arid channels on larger downstream rivers. One of the coauthors of the Science 

Report conducts and publishes research from the Walnut Gulch USDA ARS facility. Many of 

the studies cited in Section B.5 (Southwestern Intermittent and Ephemeral Streams) and Section 

3 (Streams: Physical, Chemical, and Biological Connections to Rivers) describe findings from 

Walnut Gulch, but also summarizes findings from other southwestern tributaries. These include 

intermittent and ephemeral tributaries to the Rio Grande, including ephemeral tributaries that 

drain Los Alamos National Laboratory, NM which was found to transport and store 

radionuclides that were directly discharged as effluent and indirectly as fallout from nuclear 

weapons testing into ephemeral channels and thus mediating the such contaminants in the Rio 

Grande and its downstream reservoirs (Graf 1994, Reneau et al. 2004).332 See also the summary 

responses in Section 9 “Scientific Evidence Supporting the Rule” of the Response to Comments.

The agencies recognize that there is regional variation in hydrology, climate and other factors 

throughout the U.S. that must be taken into consideration when identifying the physical features 

of tributaries such as the Ordinary High Water Mark (OHWM). The indicators discussed in RGL 

 

332 Graf, W. L., S. L. Clark, M. T. Kammerer, T. Lehman, K. Randall, and R. Schroeder. 1991. Geomorphology of 

heavy metals in the sediments of Queen Creek, Arizona, USA. CATENA 18:567-582.

Reneau, S. L., P. G. Drakos, D. Katzman, D. V. Malmon, E. V. McDonald, and R. T. Ryti. 2004. Geomorphic 

controls on contaminant distribution along an ephemeral stream. Earth Surface Processes and Landforms 29:1209-

1223.
Clean Water Rule Response to Comments – Topic 8: Tributaries

314

05 – 05 have already been applied to the hydrologic and climatic circumstances found in the arid 

southwest and western mountains in field delineation manuals. The Arid West OHWM manual 

was developed to address these challenges in low-gradient, alluvial ephemeral/intermittent 

channel forms, by using other features associated with the limits of the active floodplain 

(channel), which are easily identified in the field, less variable over time, and statistically linked 

to the hydrologic and hydraulic parameters of ephemeral and intermittent arid channel forms, to 

support the traditional OHWM indicators. This method uses stream geomorphology and 

vegetation response to the dominant stream discharge and represents the most consistent and 

repeating pattern associated with “ordinary” events representing OHW in the arid west. The 

agencies plan to continue to build on the more than a decade of effort spent improving the 

consistency and rigor of OHWM identifications, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254/Article/486

085/ordinary-high-water-mark-ohwm-research-development-and-training.aspx for updates. The 

final rule will provide additional clarity on the meaning of OHWM for determining jurisdiction 

by continuing to use same OHWM indicators and tools and adding the OHWM definition to 

EPA regulations. 

Several commenters noted that the Science Advisory Board (SAB) panel did not recommend the 

use of OHWM in the proposed rule as part of the "tributary" definition, due to regional variations 

in the use of OHWM. The SAB and these commenters were concerned that the use of OHWM

in combination with bed and banks would not capture all ephemeral streams that function as 

tributaries, and thus lead to “under coverage” of such features. These commenters along with the 

SAB recommended using “other evidence of flow” instead of OHWM.

The agencies based their significant nexus determination for the covered tributaries in part on the 

amount of flow indicated where a tributary had both a bed and banks and an indicator of 

ordinary high water mark, so the rule continues to require both physical indicators – bed and 

banks and OHWM - with the preamble at IV(F) clarifying the means to conclude that those 

indicators exist. The agencies did not conclude that other evidence of flow would be sufficiently 

specific or identifiable in the field to establish tributaries as a category of waters that is similarly 

situated with a significant nexus to (a)(1) through (3) waters. On the other hand, the agencies 

have decades of experience with the identification of OHWM across the country and are familiar 

with functions streams with OHWM support and their importance to downstream waters while 

making relatively permanent and significant nexus determinations since 2008. The identification 

of OHWM across the country and especially in the west has been the focus of significant effort 

for more than a decade and resulted in the creation of several technical guides and background 

documents which have improved the accuracy and consistency of OHWM determinations while 

also expanding the agencies’ familiarity with the various indicators of flow and OHWM found in 

rivers and streams across the western U.S. 

A number of commenters were concerned with how the use and application of OHWM would 

impact the regulatory status of MS4 systems, storm drains, stormwater systems, manmade 

channels and concrete conveyances.

The final rule includes several clarifications in the exclusions section, stating that the following 

are not waters of the U.S., including (b)(6) “Stormwater control features constructed to convey, 
Clean Water Rule Response to Comments – Topic 8: Tributaries

315

treat or store stormwater that are created in dry land.” The use of OHWM under the final rule 

does not change the agencies longstanding practice that stormwater control features created in 

dry land are not waters of the U.S. For a fuller discussion of this exclusion please see the 

summary response in section 7.4.4 of the response to comments document. 

A number of commenters were concerned about how far upstream from a break they would have 

to look to determine the location of a bed and banks and OHWM for a feature. Such breaks in 

OHWM and the burden placed on landowners were identified as especially heavy on ranchland 

and farmland.

The presence of OHWM above and below a break in the OHWM indicates that a tributary does 

contribute flow to a downstream water, and the connectivity report suggests there is a more than 

insubstantial relationship with downstream TNWs. The upper limit of the tributary is the point 

where a bed and banks and another indicator of ordinary high water mark cease to be 

identifiable. The ordinary high water mark establishes the lateral limits of a water, and its 

absence generally determines when a tributary’s channel or bed and banks has ended, 

representing the upper limit of the tributary. However, a natural or constructed break in bed and 

banks or other indicator of ordinary high water mark does not constitute the upper limit of a 

tributary where bed and banks or other indicator ordinary high water mark can be found farther 

upstream. By looking to the presence of a bed and banks and an ordinary high water mark 

upstream, the rule ensures that a mere break in the ordinary high water mark does not render 

tributaries with a significant nexus to downstream waters not jurisdictional. The agencies will 

continue the existing practice of making case by case determinations of the length of break in 

OHWM that does not sever the connection to downstream waters. Site specific conditions will 

continue to determine the distance up valley that needs to be evaluated to see if the break in bed 

and banks and OHWM is temporary or the start of the stream system. These conditions include 

the size of the stream (larger streams require looking further up valley) and the nature of the 

break (look to see the up-valley end of manmade breaks, streams buried by colluvium and valley 

bottom alluvial fans). Conversely, where the bed and banks and OHWM simply fade away or 

abruptly end at a headcut and the substrate, land use and valley characteristics do not change 

above and below the break, minimal up-valley evaluation is necessary. The time it takes for 

water to make the connection between the waters above and below a break in OHWM will 

continue to be considered when evaluating breaks in OHWM and is largely dependent on the 

nature of the break. While there has never been a time limit on connections, times much longer 

than would occur if the break was not present point to the presence of distinct waterbodies 

instead of a single waterbody. Thus, the Agencies believe that under current practice, which is 

not changed by this final rule, a reasonable limit on the length of the break in OHWM exists.

This approach will simplify implementation of the final rule. The clarification and simplification 

provided by the final rule will make it easier – not harder – for farmers and ranchers to determine 

if bed and banks and OHWM can be detected upstream. If bed and banks and OHWM can be 

detected upstream, the water body continues to be a covered tributary. In addition, normal 

farming and ranching practices have always been exempt and continue to be exempt from 404 

permitting which should alleviate much of the concern expressed by the commenters. With 

regard to the challenges faced by farmers and ranchers in finding the bed and banks and OHWM, 

the Agencies also note that certain ditches are excluded from the final rule under section (b). In 
Clean Water Rule Response to Comments – Topic 8: Tributaries

316

addition, some ditch maintenance work that is not exempted may be covered by non-reporting 

NWP 3.

Many commenters in the arid west/southwest were concerned that more ephemeral features 

would be regulated as jurisdictional tributaries compared to current practice, including ephemeral 

features that flow very irregularly and erosional features such as gullies and rills. These 

commenters stated that OHWM does not account for frequency or duration of flow, making it 

difficult to determine if a feature contributes flow.

The rule definition of “tributary” requires that flow must be of sufficient volume, frequency, and 

duration to create the physical characteristics of bed and banks and an ordinary high water mark. 

If a water lacks sufficient flow to create such characteristics, it is not considered “tributary” 

under this rule. The commenters express concern that a feature that flowed very infrequently 

could meet the proposed definition of “tributary.” However, it is the agencies’ judgment that 

features which flow infrequently for their hydrologic and climatic conditions would likely not be 

a tributary under the rule because they would not flow frequently enough to form the physical 

indicators required under the definition of “tributary”: ordinary high water mark and bed & 

banks. To further emphasize this point, the final rule expressly indicates in paragraph (b) that 

ephemeral reaches that do not meet the definition of tributary are not “waters of the United 

States.” 

The rule includes ephemeral streams that meet the definition of tributary as “waters of the United 

States” because the agencies determined that such tributary streams (even if ephemeral) provide 

important functions for downstream waters, and in combination with other covered tributaries in 

a watershed significantly affect the chemical, physical, and biological integrity of traditional 

navigable waters, interstate waters, and the territorial seas. As noted by the SAB, and consistent 

with the scientific literature, tributaries as a group exert strong influence on the chemical, 

physical, and biological integrity of downstream waters, even though the degree of connectivity 

is a function of variation in the frequency, duration, magnitude, predictability, and consequences 

of chemical, physical, and biological processes. See, e.g., SAB 2014b. These significant effects 

on traditional navigable waters, interstate waters and the territorial seas occur even when the 

tributary is small, intermittent, or ephemeral. See also the summary responses in Section 9 

“Scientific Evidence Supporting the Rule” of the Response to Comments. The extent of 

ephemeral streams covered by the final rule is less than covered under the existing regulations, 

however it may not match up exactly with past practice under the 2008 guidance. 

Issue: Need more guidance on determining OHWM and definitions of bed and banks and 

OHWM

Some commenters asked that the terms “Ordinary High Water Mark” and “bed and banks” be 

defined and explained in greater detail in the Final Rule. Some commenters recommended that 

the agencies develop additional regional guidance on identifying OHWM.

The agencies agree that regionally appropriate tools are needed for OHWM identification, and 

will continue to develop these tools to provide further clarity in identifying tributaries throughout 

the country. Corps regulations define the term “ordinary high water mark” for purposes of the 

CWA lateral jurisdiction at 33 CFR 328.3(e). In response to comments received and to increase 
Clean Water Rule Response to Comments – Topic 8: Tributaries

317

clarity, the final rule adds the Corps’ existing regulatory ordinary high water mark definition to 

EPA’s regulations. Also, to increase clarity and respond to comments, the preamble at IV.F.1. 

includes a definition of bed and banks adapted largely from longstanding agencies’ practice as 

well as comments.

Many commenters stated that the breadth of OHWM indicators found in the Corps Regulatory 

Guidance Letter 05-05 allows an OHWM to be identified in any feature with a bed and banks, 

including some erosional features or features that are not representative of ordinary conditions in 

the arid west/southwest. Many commenters from the arid west/southwest region were also 

concerned with the use of OHWM as defined in the Arid West Field Manual because it results in 

regulation of a larger lateral extent of jurisdiction within the active floodplain adjacent to the 

tributary, as compared to other areas of the country. 

The Field Guide to the Identification of OHWM in the Arid West provides additional, more 

specific guidance for identifying the OHWM within the arid west region. Due to concerns 

expressed regarding some traditional OHWM indicators that do not translate well to the arid west 

hydrologic and climatic conditions, the Corps worked within the framework of the regulation and 

Regulatory Guidance Letter 05-05 to develop a regionally appropriate delineation manual. The 

arid west OHWM delineation manual uses features associated with the limits of the active 

floodplain (more commonly known as the active channel) to support the traditional OHWM 

indicators. The active floodplain is easily identified in the field, relatively constant over time, 

and statistically linked to the hydrologic and hydraulic parameters of ephemeral/intermittent arid 

channel forms. In arid channel systems, the active floodplain functions in the same manner as the 

bankfull channel within a perennial channel form, in that most of the hydrological and fluvial 

dynamics produced by repeating effective discharges is confined within its boundaries. The

approach in the arid west OHWM delineation manual is based on stream geomorphology and 

vegetation response to the dominant stream discharge and represents the most consistent and 

repeating pattern associated with “ordinary” events representing OHW. 

Intermittent and ephemeral streams in the arid west are often much wider than intermittent and 

ephemeral streams in more humid climates due to their highly erodible soils, dramatic variation 

in precipitation and discharge among other factors. As a result, OHWM boundaries are often 

wider in the arid west than in more humid regions. 

Many commenters recommended that OHWM guidance and field manuals undergo greater 

public review and allow the opportunity for the regulated community to provide input. Several 

commenters stated that use of OHWM does not promote clarity, and suggested a need for a 

national OHWM classification system.

The U.S. Army Corps of Engineers Regulatory Guidance Letter (RGL) 05-05 provides guidance 

in OHWM identification, and has been used in OHWM determinations in the field for a decade. 

Furthermore, the agencies have developed Field Guides for OHWM Identification in regions in 

which variations in physical conditions present challenges for OHWM identification and 

delineation. These manuals include the Field Guide to the Identification of OHWM in the Arid 

West, which has been implemented since 2008 and the Guide to OHWM Delineation of Nonperennial Streams in the Western Mountains, Valleys and Coast Region of the U.S., which has 
Clean Water Rule Response to Comments – Topic 8: Tributaries

318

been implemented since 2014. These OHWM delineation manuals were subject to extensive 

internal and external peer review in accordance with longstanding agency practice for such 

technical guides.

Some commenters encouraged the agencies to include wetlands, ponds and other waters without 

an OHWM in the definition of tributary, but most commented that including these waters caused 

a lack of clarity in the definition. This issue is further addressed in Section 8.2. 

The final rule contains a definition of tributary which was modified in response to the majority of 

comments to provide increased clarity. Wetlands, lakes, ponds, and other features lacking a bed 

and banks and/or OHWM are no longer defined as tributaries in the final Rule, but may still be 

considered jurisdictional waters of the U.S. either as adjacent waters or similarly situated waters 

with a significant nexus to (a)(1) through (3) waters. This is further discussed in Section 8.2.

The OHWM is currently used to identify the lateral extent of jurisdictional waters of the U.S. 

Bed and banks and OHWM have been identified on the 2008 Rapanos Approved Jurisdictional 

Determination form as an indicator of tributary characteristics. The rule does not propose a 

change to the existing guidance and practice of identifying OHWM of streams. Presence of an 

OHWM will be used to identify features that are classified as tributaries, which have now been 

determined to have a significant nexus to downstream waters. 

Specific Comments

Washington State Department of Ecology et al. (Doc. #13957)

8.93 Washington supports the inclusion of the presence of a bed and bank and evidence of 

OHWM in the definition of tributary. Regional manuals on determining the Ordinary 

High Water Mark on tributaries will be important to ensure clarity. We recommend that 

the Corps and EPA work with states to develop regionally appropriate methods and tools 

for delineating tributaries, In response to EPA's request, we feel it is appropriate to 

include wetlands as tributaries rather than just as adjacent waters when they are part of a 

tributary system. (p. 3)

Agency Response: The final rule continues the longstanding use of OHWM to 

define the lateral extent of jurisdiction, however provides the additional clarity of 

explicitly stating the requirements for identifying the upstream extent of jurisdiction 

as well, see 33 CFR 328.3(c)(3). The Corps and EPA plan to continue to build on the 

more than a decade of effort spent improving the consistency and rigor of OHWM 

identifications, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates. 

The final rule covers, as tributaries, only those features that science tells us function 

as a tributary and that meet the significant nexus test articulated by Justice 

Kennedy. The agencies have found that wetlands, lakes and similar waters are best 

considered as adjacent waters even when in line with the tributary network, 
Clean Water Rule Response to Comments – Topic 8: Tributaries

319

however the rule makes clear that tributaries may flow through such adjacent 

waters without losing their tributary status. 

Alabama Department of Transportation (Doc. #14116)

8.94 ALDOT understands that the test to determine whether or not a water should be 

considered a tributary involves the existence of bed, banks, and an ordinary high water 

mark (OHWM). As has been acknowledged by EPA and the Corps, determination of 

OHWM can be challenging and subjective. ALDOT requests that clear guidance is 

provided in the rule for determination of OHWM. We request that OHWM clearly 

represent sustained and significant flows. (p. 2)

Agency Response: The final rule does not change the definition of or methods for 

identifying the OHWM. The agencies plan to continue to build on the more than a 

decade of effort spent improving the consistency and rigor of OHWM 

identifications, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates. 

The final rule covers, as tributaries, only those features that science tells us function 

as a tributary and that meet the significant nexus test articulated by Justice 

Kennedy. The agencies have determined that the presence of sufficient flow to form 

bed and banks and another indicator of OHWM is also sufficient to support status 

as a similarly situated class of waters with a significant nexus. Features not meeting 

the legal and scientific tests are not jurisdictional under this rule.

Commonwealth Pennsylvania Department of Agriculture (Doc. #14465)

8.95 ...uncertainty is created by:

...using the confusing concept of ordinary high water mark (OHWM) as the key 

identifier for tributaries,... (p. 4)

Agency Response: See summary response 8.1.2: Need more guidance on 

determining OHWM and definitions of bed and banks and OHWM above. 

Alameda Corridor East Construction Authority et al. (Doc. #8534.1)

8.96 The requirement to include all ditches, channels, and other conveyances that are 

perennially wet, are adjacent to traditional navigable waters, or that have a biological 

connection to traditional navigable waters will be classified as tributaries and therefore 

Waters of the United States, is overreaching and inconsistent with how the United States 

Army Corps of Engineers (Corps) currently asserts jurisdiction. As such, the Corps will 

have no choice but to start taking jurisdiction of storm drains on every project. This will 

induce unnecessary additional workload on the Corps and additional cost to analyze and 

define these features, counter to the intent of the proposed rulemaking. We believe that 

Corps jurisdiction should be specifically limited to the surface expression of natural 

drainages that convey flows to downstream receiving waters that exhibit an ordinary high 

water mark (OHWM). (p. 1)
Clean Water Rule Response to Comments – Topic 8: Tributaries

320

Agency Response: The final rule represents a narrowing of jurisdiction from the 

prior regulations. Along with a narrowing of jurisdiction, the rule also significantly 

reduces the uncertainty and number of case-specific determinations that will 

required, reducing state and federal workload associated with jurisdictional 

determinations. As described in the summary responses 8.1 and 8.1.2, for a ditch or 

other feature to be jurisdictional as a tributary it must have bed and banks and an 

OHWM and flow directly or indirectly into a (a)(1) – (a)(3) water. However all 

tributaries, because they have these characteristics, have been found to have a 

significant nexus by rule, and are therefore jurisdictional, see the TSD and 

Connectivity report for further explanation. See summary response 6.0 for a 

explanation of ditches in the final rule. With respect to stormwater control features, 

whose specific exclusion is stated in the rule, please see the summary response at 

7.4.4.

Kendall County Board, Illinois (Doc. #10965)

8.97 ...In natural systems, the OHWM is an indicator that can be readily identified and is 

typically a stable feature making it useful for delineation. Because the flow in man-made 

channels is often highly irregular and changes with maintenance, the OHWM is not a 

reliable indicator.

...Kendall County has the following objections to and concerns with the proposed rule 

Definition of Waters of the US. Under the Clean Water Act, Docket No. EPA -HQ-OW2011-0880. ...

3. We object to the use of natural stream geomorphologic conditions, including bed and 

bank and the regulatory descriptor Ordinary High Water Mark, to establish federal 

jurisdiction of a manmade drainage feature... (p. 1, 2)

Agency Response: The final rule does not change the definition of or methods for 

identifying the OHWM. The agencies plan to continue to build on the more than a 

decade of effort spent improving the consistency and rigor of OHWM identifications 

in natural and manmade features, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates. 

The final rule covers, as tributaries, only those features that science tells us function 

as a tributary and that meet the significant nexus test articulated by Justice 

Kennedy. The agencies have determined that the presence of sufficient flow to form 

bed and banks and another indicator of OHWM is also sufficient to support status 

as a similarly situated class of waters with a significant nexus. Features not meeting 

the legal and scientific tests are not jurisdictional under this rule.

Board of County Commissioners, Churchill County, Nevada (Doc. #12260)

8.98 The following are some unique attributes of the Newlands project that may be adversely 

affected by the proposed rule:...

2. The definition of tributary for purposes of the proposed regulation is "a water 

physically characterized by the presence of a bed and banks and ordinary high water 
Clean Water Rule Response to Comments – Topic 8: Tributaries

321

mark which contributes flow to a jurisdictional water". The canals of the Newlands 

Project have a bed and banks but their flow travels to cropland, not directly to the Carson 

River, or a wetland. Their "ordinary" high water mark is dependent upon which 

agricultural producers are irrigating and what time of year it is. The water in the ditches 

can vary greatly from day to day and is not "ordinary". The proposed definition of a 

tributary does not provide any clarity; it adds uncertainty. 

3. The Carson River is considered a part of the Newland s Project as it conveys water and 

it is also considered a navigable river and is under the jurisdiction of the Army Corps of 

Engineers. This is well understood in Churchill County and permits are requested when 

doing any work below the high water mark. Any further regulation pertaining 10 

"navigable waters" may have a negative impact on the current conveyance of irrigated 

water. (p. 1-2)

Agency Response: Site-specific analysis of the Newlands project is beyond the 

scope of the rule. The preamble to the final rule and the Exclusion Compendium 

provide in depth discussion of each of the exclusions. The agencies have consistently 

regulated aqueducts and canals as “waters of the United States” where they serve as 

tributaries, removing water from one part of the tributary network and moving it to 

another. In order for these canals and aqueducts, to be considered “tributary” they 

must both contribute flow and have the bed bank and another indicator of ordinary 

high water mark . 

Finally with regard to ditches, the rule provided additional clarity over the 

regulation of ditches by explicitly excluding certain categories of ditches, such as 

ditches that flow only after precipitation. See summary response 6.0. 

Weld County, Colorado (Doc. #12343)

8.99 Another of the terms that requires better definition is “ordinary high water mark 

(OHWM).” The proposed rule relies heavily on the ability to determine whether a 

waterway has a bed, bank, and ordinary high water mark. The EPA notes that 

indicators of an OHWM may vary from region to region across the country. Fed. 

Reg. Vol. 79 No. 76 at 22202.

This is especially true in the Western United states where the climactic conditions are so 

variable. The agencies acknowledge as much:

In many intermittent and ephemeral tributaries, including dry land systems in the 

arid and semi-arid west, ohwm can be discontinuous within an individual 

tributary due to the variability in hydrologic and climactic influences. Id.

This variability in water flow again makes it difficult to use Eastern definitions to impose 

rules on a Western landscape. The term ordinary high water mark assumes a level of 

regularity in flow that is often not present in the ditches and roadside borrow pits of the 

West. (p. 8)

Agency Response: The final rule continues the longstanding practice of using the 

OHWM to determine the lateral extent of jurisdiction for tributaries. Where the 

physical characteristics of bed and banks and another indicator of ordinary high 

water mark no longer exist or are actively manipulated, the presence of bed and 
Clean Water Rule Response to Comments – Topic 8: Tributaries

322

banks and OHWM may be determined by using other appropriate means that 

consider the characteristics of the surrounding areas. The OHWM continues to be 

identified using indicators of regular high flows whose return interval varies across 

the country based on climate, hydrology, and other factors. The agencies plan to 

continue to build on the more than a decade of effort spent improving the 

consistency and rigor of OHWM identifications, especially in the western US where 

two guidebooks for OHWM identification have already been developed, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates. 

Brown County, Kansas (Doc. #13603)

8.100 The definition of a tributary is based on having a bed and bank plus an ordinary high 

water mark. On ephemeral channels there is rarely water in the channel so an ordinary 

high water mark is usually speculation. This matter is so confusing to Corps staff that the 

determination of ordinary high water is buried somewhere in regulatory guidance letters. 

Usually in first order ephemeral channels the ordinary high water mark cannot be 

determined and current practice is to say if the tributary (no matter how small) has banks 

that it has an ordinary high water mark. This bureaucratic isolated decision, that if a 

channel has banks it has an ordinary high water mark, greatly extended the upstream 

extent of ephemeral tributaries to what are basically gullies or erosion features. By 

current interpretation a 1 ft. wide and 1 ft. deep channel is considered waters of the 

United States by regulators, but what citizen would believe that the federal government 

claims jurisdiction to such a small featured. Since the ordinary high water mark is so 

important on determining if a channel is considered waters of the US that this definition 

should be open for public comment and peer review. (p. 2)

Agency Response: The final rule did not change the definition or methods for 

identification of the OHWM. The final rule covers, as tributaries, only those 

features that science tells us function as a tributary and that meet the significant 

nexus test articulated by Justice Kennedy. The agencies have determined that the 

presence of sufficient flow to form bed and banks and another indicator of OHWM 

is also sufficient to support status as a similarly situated class of waters with a 

significant nexus. Features not meeting the legal and scientific tests are not 

jurisdictional under this rule. The agencies plan to continue to build on the more

than a decade of effort spent improving the consistency and rigor of OHWM 

identifications, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates. 

Board of Supervisors, San Joaquin County, California (Doc. #15017.1)

8.101 The agencies should provide assurances in a final rule that the definition of "tributary" 

will be limited to those with "bed and banks with an ordinary high water mark" that have 

formed over several decades, and that would not include temporary accumulations of 

sediment or hydraulic activity resulting from specific isolated precipitation or runoff 
Clean Water Rule Response to Comments – Topic 8: Tributaries

323

events. Definitions must be fleshed out for the terms "ordinary high water mark", "bed 

and banks", and other subjective terminology used in the proposed rule that can and will 

cause uncertainty in the implementation of a final rule. 

Also, the SAB recently advised the EPA to reconsider the definition of tributaries in the 

proposed rule because the SAB maintains that not all tributaries may have ordinary high 

water marks. The SAB stated that "an ordinary high water mark may be absent in 

ephemeral streams within arid and semi-arid environments or in low gradient landscapes 

where the flow of water is unlikely to cause an ordinary high water mark."333 The SAB 

advised the agency to "consider changing the wording in the definition to bed, bank, and 

other evidence of flow’."334 We believe this would further broaden the jurisdiction of 

the CWA beyond what Congress intended, as any indication of surface water runoff from 

an isolated rain event in a field, dirt road or parking lot could meet this new expanded 

definition, becoming a "water of the U.S." subject to CWA regulation. (p. 3-4) 

Agency Response: The final rule continues the longstanding practice of using the 

OHWM to determine the lateral extent of jurisdiction for tributaries. Where the 

physical characteristics of bed and banks and another indicator of ordinary high 

water mark no longer exist or are actively manipulated, the presence of bed and 

banks and OHWM may be determined by using other appropriate means that 

consider the characteristics of the surrounding areas. The OHWM continues to be 

identified using indicators of regular high flows whose return interval varies across 

the country based on climate, hydrology, and other factors. The agencies plan to 

continue to build on the more than a decade of effort spent improving the 

consistency and rigor of OHWM identifications, especially in the western US where 

two guidebooks for OHWM identification have already been developed, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates. See TSD section 2.A and 7.A for more information on the 

SAB review and rationale for using OHWM. 

Painesville Township, Ohio (Doc. #15183)

8.102 Definitions must be fleshed out for the terms "ordinary high water mark", "bed and 

banks", and other subjective terminology used in the proposed rule that can and will 

cause uncertainty in the implementation of a final rule. (p. 2)

Agency Response: The final rule does not change the longstanding definition of 

OHWM nor change the commonly understood definition of bed and banks. The use 

of these commonly understood terms and additional clarity provided by the 

definition tributary and specific exclusions found in the final rule will reduce 

uncertainty. 

Brady Township Supervisors, Clearfield County, Pennsylvania (Doc. #16480)

8.103 The agencies should provide assurances in a final rule that the definition of "tributary" 

will be limited to those with "bed and banks with an ordinary high water mark" that have 

formed over several years, and that would not include temporary accumulations of 

sediment or hydraulic activity resulting from specific isolated precipitation or runoff 

events. Definitions must be fleshed out for the terms "ordinary high water mark," "bed 
Clean Water Rule Response to Comments – Topic 8: Tributaries

324

and banks," and other subjective terminology used in the proposed rule that can and will 

cause uncertainty in the implementation of a final rule. Jurisdictional tributaries should 

meet a new "bright line' test related to size of bed and banks, amount of flow, or distance 

from the jurisdictional navigable water in order to be considered a "water of the U.S.", 

establishing a limit on just how small or how far upstream the CWA would apply from 

the jurisdictional navigable water. (p. 2-3)

Agency Response: For discussion of OHWM and bed and banks see response to 

comments 8.377 and 8.378 above. The final rule does not establish minimum 

requirements for the size of the bed and banks nor flow or distance to a navigable 

water for tributaries. The science and experience led the agencies to find that 

tributaries must flow directly or to another water or waters which eventually flow 

into a traditional navigable water, interstate water, or the territorial sea, but further 

restrictions based on distance or size are not warranted. For further discussion see 

the TSD and Connectivity report. 

Sienna Plantation Levee Improvement District, Sugar Land, Texas (Doc. #17455)

8.104 2. The definition proposed for "tributary" creates uncertainty and relies on newly released 

Technical guidance for identifying tributaries. The proposed definition of "tributary" -

which requires only a bed, banks and an ordinary high water mark ("OHWM") - will 

create uncertainty in many instances. While a bed, banks and OHWM can be easily 

identified in some locations, in others those features are not evident, especially an 

OHWM. The proposed rule would nevertheless make a tributary a "waters of the U.S." if, 

at any upstream location, a bed, banks and OHWM can be identified. Such a broad 

definition will potentially require examination of miles of upstream tributary features, 

quite possibly beyond areas that are accessible either due to legal or physical constraints, 

The proposed rule's reliance on being able to define and identify an OHWM to determine 

jurisdiction over tributaries does not provide clarity as there has not been established a 

reliable and repeatable means to identify an OWHM. Just shortly after the proposed rule 

was published in April 2014, the Corps of Engineers released new technical guidance 

(ERDC/CCREL TR-14-13, A Guide to Ordinary High Water Mark (OHWM) Delineation 

for Non-Perennial Streams in the Western Mountains, Valleys, and Coast Region of the 

United States) for delineating the OHWM in non-perennial streams in the Western U.S. 

The EPA has stated publicly that similar guidance is being developed for other regions. 

The Corps also released in August 2014, (ERDC/CCREL TR-14-12, A Review of Land 

and Stream Classifications in Support of Developing a National Ordinary High Water 

Mark (OHWM) Classification) a report with the objective of determining the "most

appropriate factors to include in a national OHWM classification." As the factors to be 

used in identifying OHWM's have yet to be determined it is blatantly false to claim that 

the proposed rule provides clarification and does not expand jurisdiction. (p. 3)

Agency Response: The final rule continues the longstanding use of OHWM to 

define the lateral extent of jurisdiction, however provides the additional clarity of 

explicitly stating the requirements for identifying the upstream extent of jurisdiction 

as well, see 33 CFR 328.3(c)(3). The Corps and EPA plan to continue to build on the 

more than a decade of effort spent improving the consistency and rigor of OHWM 

identifications, see 
Clean Water Rule Response to Comments – Topic 8: Tributaries

325

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates. 

Recent Corps efforts to clarify the meaning of OHWA provide additional clarity. 

The final rule covers, as tributaries, only those features that science tells us function 

as a tributary and that meet the significant nexus test articulated by Justice 

Kennedy. The rule also significantly reduces the uncertainty and number of casespecific determinations that will be required, reducing uncertainty. 

Butte County, California (Doc. #19593)

8.105 The agencies should provide assurances in a final rule that the definition of “tributary” 

will be limited to those with “bed and banks with an ordinary high water mark” that have 

formed over several years, and that would not include temporary accumulations of 

sediment or hydraulic activity resulting from specific isolated precipitation or runoff 

events. Definitions must be fleshed out for the terms “ordinary high water mark”, “bed 

and banks”, and other subjective terminology used in the proposed rule that can and will 

cause uncertainty in the implementation of a final rule.

Also, the SAB recently advised the EPA to reconsider the definition of tributaries in the 

proposed rule because the SAB maintains that not all tributaries may have ordinary high 

water marks. The SAB stated that “an ordinary high water mark may be absent in 

ephemeral streams within arid and semi-arid environments or in low gradient landscapes 

where the flow of water is unlikely to cause an ordinary high water mark.”333 The SAB 

advised the agency to “consider changing the wording in the definition to ‘bed, bank, and 

other evidence of flow’.”334 We believe this would further broaden the jurisdiction of the 

CWA beyond what Congress intended, as any indication of surface water runoff from an 

isolated rain event in a field, dirt road or parking lot could meet this new expanded 

definition, becoming a “water of the U.S.” subject to CWA regulation. (p. 5)

Agency Response: For discussion of OHWM and bed and banks see response to 

comments 8.377 and 8.378 above. The final rule retains the requirement for both 

bed and banks and another indicator of OHWM. See TSD section 2.A and 7.A for 

more information on the SAB review and rationale for using OHWM.

Association of California Water Agencies (Doc. #12978)

8.106 ...Regulatory guidance and field manuals related to delineating the “ordinary high water 

mark” should be released for public review prior to use. (p. 2)

Agency Response: The Corps and EPA are committed to a transparent regulatory 

program. The Corps and EPA plan to continue to build on the more than a decade 

of effort spent improving the consistency and rigor of OHWM identifications, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

 

333 Ibid. [[EPA-SAB-14-007] Science Advisory Board letter to EPA Administrator Gina McCarthy dated September 

30, 2014 re: Science Advisory Board (SAB) Consideration of the Adequacy of the Scientific and Technical Basis of 

the EPA’s Proposed Rule titled “Definition of Waters of the United States under the Clean Water Act”]

334 Ibid.
Clean Water Rule Response to Comments – Topic 8: Tributaries

326

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates. 

8.107 Ordinary High Water Mark Delineations Unnecessarily Broad

...Currently, in the arid west, the methodology to be used to locate and identify the 

OHWM is described in the 2008 Lichvar Field Manual.335 (It should be noted that the 

methodology in the 2008 Lichvar Field Manual differs from the methodology prescribed 

in the 2005 Regulatory Guidance Letter 0505.)

The 2008 Lichvar Field Manual presents a method for ordinary high water delineations 

associated with the ephemeral/intermittent channel forms that dominate the arid west 

landscape. The method prescribed in this report for delineating the lateral extent of 

non‐wetland waters in the arid west uses stream geomorphology and vegetation response 

to the dominant stream discharge. This approach is different and more expansive than 

that used in other regions of the U.S. The 2008 Lichvar Field Manual states, “In perennial 

channels, the bankfull zone is where the majority of the impact (via erosion and 

sedimentation) takes place owing to the presence of the dominant channel‐forming 

discharge.” Conversely, “In ephemeral/intermittent channels, the bankfull zone is 

potentially a more transient, less discernable feature, and the dominant channel‐forming 

discharge, which is similar in concept to the bankfull event of a perennial channel form, 

is conveyed by one or more low‐flow features in the active floodplain zone.” Because of 

the intermittent and seasonal nature of flows through drainages in the arid west, the active 

floodplain zone can correspond to the ten‐year floodplain or higher. Depending on the 

topography, the need to look for the OHWM at the edge of the ten‐year floodplain, rather 

than at the location of the obvious channel, can add significant acreage to jurisdictional 

delineations, because it increases the scope of jurisdiction laterally away from the incised 

channel of the drainage. In other words, the size and reach of jurisdiction around 

tributaries in the arid west would be much broader than in other areas of the U.S. using 

the methodology in the 2008 Lichvar Field Manual. In situations where flows are 

infrequent, the additional area to be included may not be characterized by hydric soils, 

facultative plants, scour or other signs of the presence of water. This discrepancy would 

result in increased mitigation for impacts to “waters of the U.S.” in the arid west as 

compared to other regions of the U.S. (p. 11-12)

Agency Response: The final rule does not change the definition or alter the 

methods for identification of OHWM. The methodology found in the 2008 manual 

mentioned in the comment applies the indicators discussed in RGL 05 – 05 to the 

hydrologic and climatic circumstances found in the arid southwest. The Arid West 

OHWM manual was developed to address these challenges in low-gradient, alluvial 

ephemeral/intermittent channel forms, by using other features associated with the 

limits of the active floodplain (channel), which are easily identified in the field, less 

variable over time, and statistically linked to the hydrologic and hydraulic 

parameters of ephemeral and intermittent arid channel forms, to support the 

traditional OHWM indicators. This method uses stream geomorphology and 

 

335 The proposed rule mentions the use of the 2008 Lichvar Field Manual on pages 22259 and 22260 of the Federal

Register notice.
Clean Water Rule Response to Comments – Topic 8: Tributaries

327

vegetation response to the dominant stream discharge and represents the most 

consistent and repeating pattern associated with “ordinary” events representing 

OHW.

Colorado Stormwater Council (Doc. #12981)

8.108 Ordinary High Water Mark. The Proposed Rule retains uncertainty regarding the 

identification of an Ordinary High Water Mark (OHWM) on features that have been 

fortified to prevent erosion. For example, certain stormwater ditches may not have a 

natural OHWM but have been armored with angular cobble to prevent head cutting. 

Based on conversations with EPA and USACE stuff, the OHWM along fortified channels 

should be identified using water stains on the channel fortification. This guidance 

presents a dilemma for MS4 permittees when determining whether or not to fortify 

upland vegetated swales: they can either leave the swale unprotected (but retain its nonWOTUS; status; they can fortify the swale but increase the potential that it will be 

WOTUS.

The CSC requests that the Proposed Rule clarify how OHWM should be identified in 

these situations. Further, CSC requests that the Agencies evaluate the advisability of 

imposing regulatory burden at locations that have been protected from future erosion and 

sediment transport events. (p. 3)

Agency Response: As discussed above in the summary response for this 

compendium, the final rule does not change the definition or indicators of Ordinary 

High Water Mark (OHWM). The final rule does provide additional clarity that all 

tributaries must contain both a bed and banks and an OHWM. Fortification of an 

upland flowpath may create bed and banks however the other OHWM indicators 

require the presence of flow. 

Flood Control and Water Conservation District, Riverside County, California (Doc. #14581)

8.109 The District agrees that the definition of Tributary should consider natural bed and bank 

and ordinary high-water mark.

But that is not enough. The frequency and amount of flow, and the effect of infiltration, 

evaporation and transpiration should be considered, too. The District believes that those 

variables may preclude determining by rule that a feature is a "tributary". In the 

southeastern Californian desert, the amount of flows and the distance they must travel 

affect whether there can be an integrated ecological system with downstream traditional 

navigable waters, interstate waters, and territorial seas.

As we have discussed, in the southeastern California desert, rainfall events are infrequent, 

and on average, minimal in size, which means that existing bed and banks in the valleys 

may have been formed during very infrequent events. During common runoff events, the 

desert provides plenty of infiltration and distributary flow paths, and as a result 

ephemeral storm runoff may never reach jurisdictional waters and form the integrated 

ecological system that a "tributary" should be part of. Thus, the lengthy periods of time 

between storms large enough to cause runoff in a desert wash to reach jurisdictional 

waters makes the connection insubstantial. Truly, in the arid desert, it is as Justice Scalia 

remarked, the CWA jurisdiction evaporates with the water. (p. 4)
Clean Water Rule Response to Comments – Topic 8: Tributaries

328

Agency Response: As discussed further in the summary response found at the 

beginning of this compendium and in the TSD and Connectivity report the science 

and agency experience support the decision to determine by rule that all waters 

meeting the definition of tributary are “waters of the United States.” The final rule 

further establishes that for a ditch or other feature to be jurisdictional as a tributary 

it must have bed and banks and an OHWM and flow directly or indirectly into a 

(a)(1) – (a)(3) water. The agencies have long recognized the unique hydrologic and 

climatic circumstances found in the arid west and have even developed a OHWM 

manual specifically to address these challenges. This method uses stream 

geomorphology and vegetation response to the dominant stream discharge and 

represents the most consistent and repeating pattern associated with “ordinary” 

events representing OHW in the arid west, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx.

Western Urban Water Coalition (Doc. #15178.1)

8.110 Several physical characteristics distinguish ephemeral and intermittent drainages in the 

arid West in addition to the Corps’ definitions...The most obvious visible difference that 

frequently distinguishes ephemeral drainages in the arid West is the lack of difference in 

vegetation associated with the drainage compared with the surrounding landscape (Photos 

1, 3, 4, and 6, Appendix A). Vegetation in the arid West responds dramatically to 

moisture. However, because there is rarely reliable moisture associated with ephemeral 

drainages in the arid West, there are typically no or few differences in species 

composition or plant density associated with ephemeral drainages. Differences in plant 

species composition and density in the arid uplands and along ephemeral drainages are 

typically more a function of differences in geology, soil type, aspect, and elevation rather 

than the location of vegetation in relation to the ephemeral drainage.

Beds and banks and OHWMs can be difficult to discern, are often discontinuous, and can 

be almost meaningless (e.g., an OHWM a few inches deep and a bed and banks along a 

drainage a few feet wide). The Corps manual on delineating the OHWM in the arid West 

(Lichvar and McColley 2008) notes that in the arid West region of the U.S., waters are 

variable and include ephemeral/intermittent and perennial channel forms. The most 

problematic OHWM delineations are associated with the commonly occurring 

ephemeral/intermittent channel forms that dominate the arid West landscape. Other than 

the topographic feature of the drainage, there is frequently little to distinguish an 

ephemeral drainage from the surrounding landscape in the arid West, particularly 

erosional features.

Intermittent drainages in the arid West have ground water levels that are shallow enough 

to support vegetation (e.g., phreatophytes) that differs from and/or occurs more densely 

than the surrounding landscape (Photos 9 and 10, Appendix A). However, other physical 

features can be similar to ephemeral drainages because ground water rarely contributes 

sufficient flow to form an OHWM and/or a bed and banks; therefore, as with ephemeral 

drainages, these features are still formed by infrequent precipitation events.
Clean Water Rule Response to Comments – Topic 8: Tributaries

329

The concept of the OHWM determining if a stream is jurisdictional and the lateral limits 

of that jurisdiction is tied to the OHWM being formed by frequent flow events. This 

relationship has been determined on streams in the more humid regions of the U.S., but 

this relationship in the arid West is not supported by observations, studies and the 

literature. A simple relationship between a morphologic variable and discharge is 

successful only for streams with definable regular flows or some definable steady state; 

this is not the case for dryland streams (Graf 1988, p. 104). The OHWM for streams in 

regions outside of the arid West is associated with a bankfull flow typically considered to 

have a return interval of 1 to 2 years. In more humid regions of the country, streams will 

equal or exceed the mean annual flood once every 2.33 years. However, metrics like the 

mean annual flood and the return interval of bankfull flow have almost no practical or 

theoretical significance in dryland streams because of the extreme variability of flow in 

such streams (Graf 1988, p. 103). In arid areas channels may not have any flow for 

several years. Bankfull flows are difficult to determine in the field in dryland channels 

that are frequently incised, very broad or braided, or developed on bedrock. Bankfull 

flow in dry areas is not even the same within a single drainage basin. Extensive data 

collection show that the range of frequency of bankfull flows in dryland channels is from 

1 to 32 years, a breadth too great to inspire confidence in the reliability of the measure

(Graf 1988, p. 104).

The difficulty in transferring concepts of channel behavior from humid to dryland areas 

lies in the underlying assumptions of continuous system operation with well-defined 

feedback mechanisms, assumptions that are not met in the dryland process (Graf 1988, p. 

197). Precipitation and runoff inputs to dryland channels are sporadic, so the difference 

between high and low flows is greater than in humid streams. These wide fluctuations 

prevent the development of a linkage between a particular flow magnitude and channel 

geometry related to bankfull conditions (Graf 1988, p. 296). The order of events of 

varying magnitudes may be more important in explaining the present observed 

geomorphic conditions than the exact nature of the flood frequency curve or the statistical 

properties of flood frequencies (Graf 1988, p. 104). 

Clearly, the use of an OHWM (a morphologic variable or geomorphic condition) to 

determine that an ephemeral or intermittent channel in the arid West is a “tributary” and 

then making the assumption that the ephemeral or intermittent channel has a significant 

nexus to a TNW and is therefore jurisdictional, as the rule proposes, is not supported by 

observation, studies or the literature. (p. 17-19)

Agency Response: As discussed further in summary response 8.1 and 8.1.2 above

and in the TSD and Connectivity report the science and agency experience support 

the decision to determine by rule that all waters meeting the definition of tributary 

are “waters of the United States.” The final rule further establishes that for a ditch 

or other feature to be jurisdictional as a tributary it must have bed and banks and 

an OHWM and flow directly or indirectly into a (a)(1) – (a)(3) water. The agencies 

have long recognized the unique hydrologic and climatic circumstances found in the 

arid west and have even developed a OHWM manual specifically to address these 

challenges. This method uses stream geomorphology and vegetation response to the 

dominant stream discharge and represents the most consistent and repeating 

pattern associated with “ordinary” events representing OHW in the arid west, see 
Clean Water Rule Response to Comments – Topic 8: Tributaries

330

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx. See also the summary response 8.1.2: Use of OHWM 

inappropriate/appropriate – will lead to over/under coverage of features above. 

State of Nevada Department of Conservation et al. (Doc. #16932)

8.111 The categorical definitions presented in the Proposed Rule are problematic because they 

do not capture the intent of the CWA. Application of the proposed definitions under 

varied environmental conditions leads to inappropriate results, such as the inclusion of 

marginal waters or dry channels which obviously have no significant connection to 

jurisdictional waters.

The complexity involved in hydrologic definitions is highlighted by a recent attempt by 

the Corps to explain how to identify the location of an Ordinary High Water Mark 

(Occurrence and Distribution of Ordinary High Water Mark (OHWM) Indicators in NonPerennial Streams in the Western Mountains, Valleys and Coast Region of the United 

States, August 2014). The document is 26 pages long and only applies to discrete 

portions scattered throughout the West, none however within the boundaries of Nevada. 

It demonstrates the complex dependence of a simple definition upon specific 

environmental conditions, which vary greatly from region to region. This can result in 

one definition having a number of interpretations even within a single state, which is 

confusing and counterproductive. (p. 4)

Agency Response: See response to comment from Flood Control and Water 

Conservation District, Riverside County, California (Doc. #14581) above regarding 

the importance of various channel types that qualify as tributaries. In addition, the 

Corps and EPA plan to continue to build on the more than a decade of effort spent 

improving the consistency and rigor of OHWM identifications, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates. 

Montana Association of Conservation Districts (Doc. #18628)

8.112 Waters that are regulated by dams or irrigation withdrawals and inputs will have a more 

variable flow than those based on less flashy or consistent hydrology and will be less 

likely to have a readily identifiable ordinary high water mark. Further, these ordinary 

high water marks may vary over time as conditions change, be identified differently by 

different people, or be erased by a 100 year flood. Will the area encompassed by an 

“ordinary high water mark” be subject to change over time? If water regimes alter due to 

drought and precipitation variations, which high water mark is the actual high water 

mark? (p. 1)

Agency Response: The final rule does not change the definition or alter the 

methods for identification of OHWM. Determinations of jurisdiction are done on a 

case by case basis based on the best information available and they are only valid 

for five years because, as the commenter points out, environmental conditions which 

can shape the outcome can change over time. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

331

Water Advocacy Coalition (Doc. #7981)

8.113 In addition to releasing new information, the Agencies continue to revise and remove 

previous blog posts and statements released throughout the comment period... in 

discussing "ordinary high water mark" (OHWM), the June 30 Q&A document provided, 

"Features that .flow extremely rarely would not exhibit these characteristics and would 

not be jurisdictional." (emphasis added). Now, the document has been revised to state, 

"Water features that don't flow frequently enough or with enough volume to exhibit these 

characteristics would not be jurisdictional." (emphasis added). Not only are these 

sentences not accurate, but the meanings are different. Again, the Agencies are changing 

their story without explanation or notice. Have the Agencies changed their position on 

OHWM? How is the public to comment when the Agencies keep revising their stance on 

important issues without notice? (p. 3-4)

Agency Response: The agencies have requested public comments on the proposed 

rule and preamble, to inform development of the final rule. The final rule has not 

changed the definition or altered the long standing methods for identification of 

OHWM. The above difference in wording laid out above does not contradict each 

other nor represent a change to the agencies use of OHWM. The scientific 

literature, and the conclusions of the Connectivity Report supports the agencies’ 

conclusion that bed and banks and another indicator of OHWM establish the 

presence of sufficient flow to for a ditch or other feature to have a significant nexus. 

8.114 Moreover, a review of the OHWM guidance documents issued by the Corps 

demonstrates that, contrary to the Agencies' statements in the context of the "waters of 

the United States" rule, determination of the OHWM is anything but simple or clear. In 

various blog posts, stakeholder calls, and statements released by the Agencies during the 

comment period, the Agencies have touted the OHWM as "well-known" and "easy to 

observe and document."336 But the recent Corps statements and publications paint a 

different picture. In March 2014, the Corps recognized that OHWM is a "vague 

definition," leading to "inconsistent interpretation of [the] OHWM concept," and 

"inconsistent field indicators and delineation practices."337 Likewise, the Corps' Western 

Mountains OHWM Guidance states that "OHWM delineation in non-perennial (i.e. , 

intermittent and ephemeral) streams can be especially challenging" and notes that "it is 

often difficult to determine what constitutes ordinary high water and to interpret the 

physical and biological indicators established and maintained by ordinary high water 

flows."338 For these reasons, the Corps' National OHWM Review recognizes the "need 

for nationally consistent and defensible regulatory practices" and suggests that "a 

comprehensive framework is needed."339

In light of the confusion surrounding OHWM definition, it is difficult to understand why 

the Agencies would rely on OHWM as a determinative measure of CWA jurisdiction 

 

336 See, e.g. , Tom Reynolds, Mapping the Truth, EPA Connect Blog (Aug. 28, 2014), 

http://blog.epa.gov/epaconnect/2014/08/mapping -the-truth/

337 Presentation by Matthew K. Mersel, U.S. Army Engineer Research and Development Center, Development of 

National OHWM Delineation Technical Guidance (March 4, 2014).

338 Corps Western Mountains OHWM Guidance at 1-2.

339 National OHWM Review at 1-2.
Clean Water Rule Response to Comments – Topic 8: Tributaries

332

over tributaries.340 Indeed, the Science Advisory Board (SAB) panel questioned the 

proposed rule's use of OHWM as part of the "tributary" definition, and panel members 

were “concerned about the definition of tributary being anchored in something as 

regionally variable” as the OHWM concept.341 There is a serious disconnect between the 

Agencies' statements that the OHWM is easy to determine and the Corps' guidance 

documents and recent statements to the contrary. These mixed messages from the 

Agencies make it difficult for the public to provide meaningful comment on the proposed 

rule. (p. 5)

Agency Response: The agencies have requested public comments on the proposed 

rule and preamble, to inform development of the final rule. The final rule has not 

changed the definition or alter the long standing methods for identification of 

OHWM. The Corps and EPA plan to continue to build on the more than a decade 

of effort spent improving the consistency and rigor of OHWM identifications, 

including the development of the guidebook the mentioned in the comment, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates. See summary response 8.1.2 above and TSD section 2.A 

and 7.A for more information on the SAB review and rationale for using OHWM.

John Deere & Company (Doc. #14136.1)

8.115 The Proposed Definition For Tributary Sets Forth Poorly Defined and Optional Criteria 

Creating Confusion and Uncertainty

...

In this part of the definition the phrase “ordinary high water mark” lacks criteria making 

it susceptible to different interpretations by qualified professionals, thereby leading to 

confusion and uncertainty as identification occurs in the field. This confusion is further 

compounded by two factors: First, the term tributary includes within it water features, 

such as ponds and lakes, which do not have the characteristic inherent in the definition of 

tributaries. Second, other wet areas on land that do not possess a bed and a bank and an 

ordinary high water could have their jurisdictional status altered if a tributary runs 

through it. For example, a wet area, that did not otherwise meet the definition of a 

jurisdictional water, could now be captured and labeled as jurisdictional if a tributary ran 

through it and exited the other side.342 (p. 8)

Agency Response: The final rule has not changed the definition or alter the long 

standing methods for identification of OHWM. The final rule has also responded 

to the comments concerning the potential confusion created by calling ponds and 

similar waters tributaries. In the rule ponds, lakes and similar waters fall under the 

 

340 These concerns are not new. In Rapanos, Justice Kennedy criticized the Agencies' use of OHWM to determine 

whether tributaries are jurisdictional, because he was concerned that such a standard was overbroad and would leave 

room for the Agencies to assert jurisdiction over waters that do not have a significant nexus to traditional navigable 

waters. Rapanos v. United States, 547 U.S. 715, 781-82 (2006) (Kennedy, J. , concurring).

341 See Bridget DiCosmo, lnsideEPA.com, EPA Appears to Reject SAB Calls to Clarify Controversial "Waters" 

Proposal (Aug. 22, 2014).

342 79 Fed. Reg. 22,274 (April 21, 2014).
Clean Water Rule Response to Comments – Topic 8: Tributaries

333

adjacency standard (a)(6), see Section 3 of the Response to Comments for further 

discussion. Tributaries must have bed and banks and another indicator of OHWM

and flow directly or indirectly into a (a)(1) – (a)(3) water. Once a water is 

determined to be a tributary and does not fall under one of the exclusions, it is 

jurisdictional.

Arizona Chamber of Commerce and Industry (Doc. #14639)

8.116 The use of the ordinary high water mark concept to define what waters may be subject to 

jurisdiction is problematic as applied to arid landscapes. What may be considered as an 

“ordinary” high water mark on ephemeral drainage features in the arid West may, in 

many instances, have been formed by a single storm event and does not relate in any way 

to where water may flow in the future. Indeed, the Corps’ own research demonstrates that 

the presence of an “ordinary” high water mark in arid landscapes has no relationship to 

present or future flows. Thus, rather than being an indicator of ordinary conditions or 

potential flows—as is the case in more humid environments—the “ordinary” high water 

mark will result in a broad regulatory overreach when used to define “waters” in the arid 

West. (p. 2)

Agency Response: See summary response 8.1.2 and response to comment from 

Flood Control and Water Conservation District, Riverside County, California (Doc. 

#14581) above. 

Steel Manufacturers Association and Specialty Steel Industry of North America (Doc. #15416)

8.117 ...the definition of tributaries is ambiguous and, therefore, creates a great deal of 

confusion and jurisdictional uncertainty. The proposed rule defines tributaries as 

waterbodies that have beds, banks, and an ordinary high water mark. But stormwater 

structures and retention ponds often have a bed, banks, and an ordinary high water mark, 

thus potentially classifying them as "tributaries." Fully constructed stormwater measures, 

however, should clearly be part of the class of waters excluded from jurisdiction by rule, 

and any waterbodies EPA and the Army Corps wish to regulate could be specifically 

named as not being exempted by rule. This would decrease the number of waters that 

necessitate a case-by-case analysis, and promote green infrastructure projects like storm 

water retention and detention structures. (p. 8-9)

Agency Response: The agencies added exclusions for groundwater and erosional 

features, as well as exclusions for some waters that were identified in public 

comments as possibly being found jurisdictional under proposed rule language 

where this was never the agencies’ intent, such as stormwater control features 

constructed to convey, treat, or store stormwater, and cooling ponds that are 

created in dry land. These exclusions reflect current agencies’ practice, and their 

inclusion in the rule as specifically excluded furthers the agencies’ goal of providing 

greater clarity over what waters are and are not protected under the CWA.

GBMC & Associates (Doc. #15770)

8.118 ...Evidence of a true bed and bank in ephemeral streams may constitute a significant 

nexus; however, while indicators of other ordinary high water marks provide evidence of 
Clean Water Rule Response to Comments – Topic 8: Tributaries

334

water flow in an area, these other indicators do not necessarily provide evidence of a 

"measure of significance for connection to downstream water quality".

The rule should clarify that ordinary high water marks alone do not qualify a stream to be 

defined as a water of the United States. Regulation of the upper reaches of many of these 

ephemeral streams that primarily have the function of transporting storm water runoff 

(including constituents contained in the runoff) is beyond the scope of the original intent 

of the definition of waters of the United States. We request that in the USACE response 

to these comments that they clarify what qualifies as OHW features and bed and banks. 

Please include photos of small first order tributaries that qualify and some that do not. (p. 

3)

Agency Response: The final rule has not changed the definition or altered the 

long standing methods for identification of OHWM. For a stream to be 

jurisdictional as a tributary it must have bed and banks and an OHWM and flow 

directly or indirectly into a (a)(1) – (a)(3) water. However all tributaries have been 

found to have a significant nexus by rule, and are therefore jurisdictional. The 

Corps and EPA plan to continue to build on the more than a decade of effort spent 

improving the consistency and rigor of OHWM identifications, including the 

development of the guidebook the mentioned in the comment, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates.

Water Advocacy Coalition (Doc. #17921.1)

8.119 Bed, banks, and OHWM can be seen even in features without ordinary flow. Particularly 

in the desert and semi-arid regions of the United States, field indicators of an OHWM can 

develop very easily. Naturally sparse vegetation and erodible soils of the deserts 

combined with monsoon storms results in a significant number of small channels (often 

only a few feet in width) yet with a defined bed and bank. Many of these features would 

likely not develop in humid regions of the U.S. and would be representative of 

unregulated sheet flow or upland-vegetated swales in humid regions. Therefore, the arid 

States are unfairly burdened by the OHWM concept, compared to Eastern and humid 

states. Crossing the threshold from a non-jurisdictional erosion feature to an albeit small 

channel with an OHWM in the desert occurs easily and is a significant source of 

jurisdictional uncertainty. Many of these exceedingly small channels would now become 

per se jurisdictional tributaries, even with discontinuous surface connections to another 

water and a speculative nexus to traditional navigable waters, interstate waters, territorial 

seas, and/or impoundments. (p. 44)

Agency Response: See summary response 8.1.2 and response to comment from 

Flood Control and Water Conservation District, Riverside County, California (Doc. 

#14581) above. 

8.120 2. The tributary definition does not provide clarity, but creates confusion.

In addition to its broad reach, the tributary definition is problematic because it relies on 

vague language and confusing concepts, including the following:
Clean Water Rule Response to Comments – Topic 8: Tributaries

335

 Ordinary high water mark: OHWM is the lynchpin concept of the “tributary” 

definition. As recently as March 2014, Corps experts have said that the term 

OHWM is one of the most inconsistent and ambiguous terms in the CWA 

regulatory program.343 Inconsistent interpretations of the OHWM concept have 

led to inconsistent field indicators and delineation practices. Id. The agencies do 

not propose a new definition of OHWM in this rulemaking, but rely on the 

existing, imprecise regulatory definition, which is problematic because many of 

the OHWM physical indicators can occur wherever land may have water flowing 

across it, regardless of frequency or duration. These indicators (e.g., changes in 

character of the soil, destruction of native terrestrial vegetation, presence of litter 

and debris)344 can be observed in very small drainages and even in upland areas, 

especially in arid areas. The agencies’ proposed definition of “tributary” cannot 

possibly provide clarity when its fundamental concept is a well-known source of 

confusion for the regulators themselves.

Moreover, the standard for determining OHWM is currently in flux. Separate from 

the proposed rulemaking, the agencies are redefining OHWM without the required 

public notice and comment. In August 2014, the Corps Engineer and Research 

Development Center (ERDC) released three new guidance documents regarding 

OHWM, which indicate that the agencies are developing a new OHWM standard.345

These guidance documents essentially ignore the current regulatory definition at 

section 328.3(e) and the Corps’ RGL 05-05346 and create a new method for 

determining OHWM based on the delineation of an “active channel signature” 

through the use of three primary indicators – topographic break in slope, change in 

sediment characteristics, and change in vegetation characteristics. In effect, other 

physical indicators explicitly referenced in section 328.3(e) are superfluous under this 

new methodology. This is a clear change in regulatory practice and will have a 

substantial effect on how CWA jurisdiction is interpreted. What OHWM standard 

will be applied in the field? How will the Corps account for potential inconsistencies 

 

343 Matthew K. Mersel, U.S. Army Corps of Engineers, Cold Regions Research and Engineering

Laboratory, Development of National OHWM Delineation Technical Guidance (Mar. 4, 2014), available at

http://insideepa.com/sites/insideepa.com/files/documents/apr2014/epa2014_0760.pdf.

344 Robert W. Lichvar and Shawn M. McColley ,U.S. Army Corps of Engineers, A Field Guide to the Identification 

of the Ordinary High Water Mark (OHWM) in the Arid West Region of the Western United States, at 20 (Aug. 

2008), available at

http://www.spk.usace.army.mil/Portals/12/documents/regulatory/pdf/Ordinary_High_Watermark_Manual_Aug_200

8.pdf

345 Matthew K. Mersel and Robert W. Lichvar, U.S. Army Engineer Research and Development Center

(ERDC), A Guide to Ordinary High Water Mark (OHWM) Delineation for Non-Perennial Streams in the Western

Mountains, Valley, and Coast Region of the United States (Aug. 2014),

http://acwc.sdp.sirsi.net/client/search/asset/1036027; Matthew K. Mersel, et al., Occurrence and Distribution of

Ordinary High Water Mark (OHWM) Indicators in Non-Perennial Streams in the Western Mountains, Valleys, and

Coast Region of the United States (Aug. 2014), http://acwc.sdp.sirsi.net/client/search/asset/1036025; Matthew K.

Mersel, Lindsey E. Lefebvre, and Robert W. Lichvar, U.S. Army Engineer Research and Development Center

(ERDC), A Review of Land and Stream Classifications in Support of Developing a National Ordinary High Water

Mark (OHWM) Classification (Aug. 2014), http://acwc.sdp.sirsi.net/client/search/asset/1036026.

346 See U.S. Army Corps of Engineers, Regulatory Guidance Letter No. 05-05, Ordinary High Water Mark

Identification (Dec. 7, 2005), available at http://www.usace.army.mil/Portals/2/docs/civilworks/RGLS/rgl05-05.pdf.
Clean Water Rule Response to Comments – Topic 8: Tributaries

336

with section 328.3(e) and RGL 05-05? Why are the Corps’ efforts to redefine 

OHWM, a key term in the agencies’ proposed “waters of the United States” 

definition, not a part of this rulemaking? 

... (p. 47-48)

Agency Response: The agencies have requested public comments on the proposed 

rule and preamble, to inform development of the final rule. The final rule has not 

changed the definition or alter the long standing methods for identification of 

OHWM, there are no inconsistencies between RGL 05-05 and the final rule. The 

Corps and EPA plan to continue to build on the more than a decade of effort spent 

improving the consistency and rigor of OHWM identifications, including the 

development of the guidebook the mentioned in the comment, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates. The two existing regional OHWM delineation manuals 

and any future manuals developed do not mean the definition of OHWM is in flux. 

These manuals have not and will not change the definition of OHWM but simply 

help field staff more consistently apply the regulation and concepts from RGL 05-05 

to the specific hydrologic, climatic, and landscape conditions of a given region. See 

also summary response 8.1.2 above. 

National Association of Home Builders (Doc. #19540)

8.121 a. Identifying Geomorphic Features Needed to Meet the Tributary Definition, 

Particularly Ordinary High Water Mark, has Proven Difficult for the Agencies and 

will Increase Regulatory Uncertainty.

The proposed rule requires only the presence of a bed, a bank, and an OHWM, and the 

contribution of flow to a traditional navigable water, an interstate water, a territorial sea, 

or an impoundment for a water to meet the "tributary" definition. A bed, a bank, and an 

OHWM represent limited criteria to qualify water or - in instances when surface water is 

not present - land features as tributaries. Let's not forget that the CWA authorizes federal 

jurisdiction only over "water."347 While these three features appear to represent a simple 

approach to identifying tributaries, there is in fact great variability in channel form,348 and 

identifying certain tributary features can be challenging. This is particularly true with 

respect to OHWM .

In the absence of adjacent wetlands, OHWM is intended to determine the lateral limits of 

jurisdiction of non-tidal waters.349 A 2004 Government Accountability Office (GAO) 

report, however, noted significant inconsistencies among Corps districts in identifying 

waters of the United States, particularly with respect to identifying an OHWM.350 In 

“Channel Classification across Arid West Landscapes in Support of OHW[M] 

Delineation'' the Corps states, "channel types have pronounced spatial and temporal 

 

347 33 USC S - C 6., 1362(7).

348 Dunne, T., andL.B. Leopold. Water in Environmental Planning. New York: W.H. Freeman and Co., 1978. Print.

349 33 C.F.R 328.4(c)(a).

350 GAO-04-297, at 3-4.
Clean Water Rule Response to Comments – Topic 8: Tributaries

337

variability in channel morphology," and "physical features found along a channel vary 

between types, along the length of any given stream, and through time at a single 

point."351 The Corps continues, "because of the diversity and dynamic in channels, no 

single classification satisfies all needs or includes all channel types." OHWM, defined as 

'that line on the shore established by the fluctuations of water and indicated by physical 

characteristics such as clear, natural line impressed on the bank, shelving, changes in the 

character of soil, destruction of terrestrial vegetation, the presence of litter and debris, or 

other appropriate means that consider the characteristics of the surrounding areas,"352 has 

been referred to as '"vague" and responsible for "inconsistent interpretation of the 

OHWM concept" and "inconsistent field indicators and delineation practices" in a recent 

Corps presentation (Fig. 3).353

Figure 3: Slide from U.S. Army Corps of Engineers presentation dated March 4, 2014, indicating the limitations of 

using "ordinary high water mark" (OHWM) to identify "waters of the United States.228

The Corps has had a particularly difficult time identifying OHWM in the arid western 

United States, where xeric conditions generate innumerable ephemeral and intermittent 

streams. In these non-perennial reaches, the flashiness of storm events and the frequent 

shifting of the channel morphology make it challenging to identify the OHWM. limited 

data and changing flow conditions across these ephemeral and intermittent streams also

increase the difficulty the Corps faces when identifying the magnitude and frequency of 

an ordinary high discharge at a site.354 Although the Corps states there is “extreme 

 

351 U.S. Army Corps of Engineers Engineer Research and Development Center. Channel Classification across Arid I

West Landscapes in Support of OHW Delineation, Lefebvre L., R Lichvar, K. Curtis, J. Gillrich (Jan. 2013).

352 33 C.F.R. 9 328.3(e)

353 Presentation by Matthew K. Mersel, U.S. Army Corps of Engineers Engineer Research and Development Center.

Development of National OHWM Delineation Technical Guidance (March 4,2014).

354 See id. at 60
Clean Water Rule Response to Comments – Topic 8: Tributaries

338

variation” in ordinary high flows throughout the arid West region and OHWM is “highly 

variable,”355 today’s proposal nonetheless continues to rely on this problematic feature. 

With regard to ordinary high flow and OHWM, the Corps admits it is challenging to 

determine what is “ordinary” to a channel. A study by the Corps in the Arid West 

revealed a < 1 to 15.5 year range in flood frequency necessary to generate an OHWM in 

ephemeral streams.356 In that study, the Corps stated that this “large variation in 

recurrence intervals for the field OHWMs makes it impossible to define the frequency of 

the ordinary high flow from gage data because the OHW[M] event is unique to each 

channel.”357

Given the difficulty the Corps has had identifying OHWM under current regulatory 

guidance, there is substantial reason to believe the proposed rule will not clarify “waters 

of the United States” under the new tributary definition, and the current regulatory 

uncertainty surrounding the jurisdiction of the CWA will regrettably remain. (p. 60-62)

Agency Response: The final rule has not changed the definition or alter the long 

standing methods for identification of OHWM. The Corps and EPA plan to 

continue to build on the more than a decade of effort spent improving the 

consistency and rigor of OHWM identifications, including the development of the 

guidebook the mentioned in the comment, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates. See also summary response 8.1.2 above.

Minnkota Power Cooperative, Inc. (Doc. #19607)

8.122 A main focus of the proposed tributary definition is having an ordinary high water mark 

(OHWM). This OHWM in the context of this Proposed Rule, and throughout much of the 

CWA is quite ambiguous and inconsistent, thereby making a determination as a tributary 

that much more erroneous. If the OHWM is to be used, it should be clearly defined or 

referenced to an existing science-based definition. This definition, if again proposed 

should be part of a new Proposed Rule that is subject to public review and comment. (p. 

2)

Agency Response: The final rule has not changed the definition or alter the long 

standing methods for identification of OHWM. The Corps and EPA plan to 

continue to build on the more than a decade of effort spent improving the 

consistency and rigor of OHWM identifications, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates.

 

355 See id. at 3, 59.

356 See id. Table 4 at 24.

357 See id. at ii.
Clean Water Rule Response to Comments – Topic 8: Tributaries

339

American Society of Civil Engineers (Doc. #19572)

8.123 Ordinary High Water Mark: While the definition of OHWM is relativity established in 

the proposed rule for naturalized streams we believe the definition is less clear for 

OHWM’s found on concrete conveyances that may be considered jurisdictional. As we 

understand, staining is the primarily indicator to determine the OHWM in concrete 

channels, however, our members provided examples of concrete conveyances that flow a 

few times a year, carrying only sheetflow, which does not leaving stain lines. We urge 

EPA and USACE to revise the definition of OHWM as it relates to concrete conveyances 

and sheetflow. (p. 9)

Agency Response: The final rule continues the longstanding practice of using the 

OHWM to determine the lateral extent of jurisdiction for tributaries. Where the 

physical characteristics of bed and banks and another indicator of ordinary high 

water mark no longer exist or are actively manipulated, the presence of bed and 

banks and OHWM may be determined by using other appropriate means that 

consider the characteristics of the surrounding areas. The OHWM continues to be 

identified using indicators of regular high flows whose return interval varies across 

the country based on climate, hydrology, and other factors. The agencies plan to 

continue to build on the more than a decade of effort spent improving the 

consistency and rigor of OHWM identifications, especially in the western US where 

two guidebooks for OHWM identification have already been developed, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates.

Southpace Properties, Inc. (Doc. #6989)

8.124 The proposed rulemaking creates further complications due to its reliance on the 

confusing concept of ordinary high water mark (OHWM) as the key identifier for 

tributaries. (p. 1)

Agency Response: The final rule has not changed the definition or alter the long 

standing methods for identification of OHWM. The Corps and EPA plan to 

continue to build on the more than a decade of effort spent improving the 

consistency and rigor of OHWM identifications, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates.

Kerr Environmental Services Corp. (Doc. #7937.1)

8.125 The "Jurisdictional Determination Form Instructional Guidebook" prepared jointly by the 

USEPA and USACE (May 30, 2007) as a means of interpreting the Rapanos decision 

indicates that a:

"Tributary is a natural man-altered, or man-made water body. Examples include 

Rivers, streams and lakes that flow directly or indirectly into TNWs."

This definition should continue to be the regulatory definition and be reinforced by 

adding the phrase 
Clean Water Rule Response to Comments – Topic 8: Tributaries

340

"and in all cases possesses an ordinary high water mark." (p. 7)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. In the Final Rule, by 

definition tributaries must have bed and banks and an OHWM, as well as 

contribute flow to an (a)(1) through (3) water. Lakes, wetlands, and other features 

lacking these physical characteristics are no longer defined as tributaries in the 

Final Rule, but may be considered jurisdictional waters of the U.S. as adjacent 

waters or similarly situated waters with a significant nexus to (a)(1) through (3) 

waters.

Portland Cement Association (Doc. #13271)

8.126 Given the breadth of the Agencies' understanding of the terms "bed and bank" and 

"ordinary high water mark," the breadth of this standard is well beyond the scope of the 

Act.

In their April 2011 draft guidance regarding Waters of the US,358 the Agencies stated that

A tributary is physically characterized by the presence of a channel with defined 

bed and bank. The bed of a stream is the bottom of the channel. The lateral 

constraints (channel margins) are the stream banks. Channels are formed, 

maintained, and altered by the water and sediment they carry, and the forms they 

take can vary greatly.

A means of identifying the lateral limits of a tributary, including where there are 

no contiguous wetlands, is the existence of an ordinary high water mark 

(OHWM).359

In other words, an OHWM can be used to show where the banks of the tributary lie. The 

Corps guidance identifying how to identify an ordinary high water mark." states that 

The following physical characteristics should be considered when making an

OHWM determination, to the extent that they can be identified and are deemed

reasonably reliable:

Natural line impressed on the bank

Shelving

Changes in the character of soil

Destruction of terrestrial vegetation Presence of litter and debris Wracking

Vegetation matted down, bent, or absent

Sediment sorting

 

358 Available at http://www.epa.gov/tp/pdf/wous_guidance_4-2011.pdf. While this guidance document was a draft 

guidance and was not finalized in favor of publishing the proposed rule, the document specifically notes that it 

“clarifies how the EPA and the Corps understand existing requirements of the CWA and the agencies' implementing 

regulations in light of SWANCC and Rapanos. . . ” Id. at 1. In other words it “clarif[ies] their existing 

understandings. . . “ Id. Thus, it provides useful insight into the agencies’ understanding of the regulatory scheme.

359 Id. at 11
Clean Water Rule Response to Comments – Topic 8: Tributaries

341

Leaf litter disturbed or washed away

Scour

Deposition

Multiple observed flow events

Bed and banks

Water staining

Change in plant community360

These criteria cover almost every conceivable manner of proving that water has run off or 

through an area, including seeing water run in a place on more than one occasion 

(referred to as “multiple observed flow events”), bent vegetation and the washing away of 

leaves. This test is incredibly broad and well beyond the plain meaning of the CWA. It is 

certainly beyond the scope of the CWA as interpreted by the Supreme Court, which has 

confirmed that there must be some limits to CWA jurisdiction.

As such, the Agencies’ assertion that all ephemeral waters are always jurisdictional is 

without basis in the CWA and it must not adopt this part of the rule. (p. 13-14)

Agency Response: The final rule does not change the definition or alter the 

methods for identification of OHWM. The agencies have concluded that flow of a 

sufficient volume, frequency, and duration create and maintain the physical 

characteristics of tributaries, such as bed and banks and another indicator of 

OHWM. The Connectivity Report supports the scientific conclusion that all features 

that meet this definition of tributary impact the physical, chemical, and biological 

integrity of downstream waters and therefore have a significant nexus to (a)(1) 

through (3) waters. For a further discussion of the limits of CWA jurisdiction in 

regards to tributaries and the use of OHWM see the summary responses 8.1 and 

8.1.2 and the TSD. 

El Dorado Holdings, Inc. (Doc. #14285)

8.127 5. The significance of the “bed and banks” requirement, if any, should be explained: The 

proposed definition of “tributary” in 33 C.F.R. § 328.3(c)(5) requires that the water 

possess a “bed and banks” as well as an ordinary high water mark. The phrase “bed and 

banks” is not defined, nor are the individual terms “bed” or “banks.” In the preamble, the 

agencies merely indicate that in “many” tributaries, the bed is that part of the channel 

below the OHWM, and the banks often extend above the OHWM. See 79 Fed. Reg. at 

22202. The effect of requiring that a bed and banks be present along with an OHWM is 

unclear. Do bed and banks exist only in conjunction with an OHWM, or can the features 

exist independently (i.e., can an OHWM be present without bed and banks, or can bed 

and banks be present without an OHWM?)

Recommendation: The agencies need to explain the significance of the “bed and banks” 

requirement, and specifically whether it means that some channels that possess an 

 

360 Id. at 3.
Clean Water Rule Response to Comments – Topic 8: Tributaries

342

OHWM (as interpreted by the agencies) would not be jurisdictional because they do not 

also possess a “bed and banks.” (p. 17)

Agency Response: The final rule clearly requires the presence of both bed and 

banks and another indicator of OHWM, if one is not present then the water does 

not qualify as a tributary. Bed and banks can be naturally formed by repeated flow 

of water or artificially constructed out of rock, concrete, etc, however both bed and 

banks and another indicator of OHWM must be found before a water can be called 

a tributary under the rule. The agencies have concluded that flow of a sufficient 

volume, frequency, and duration create and maintain the physical characteristics of 

tributaries, such as bed and banks and another indicator of OHWM. The 

Connectivity Report supports the scientific conclusion that all features that meet 

this definition of tributary impact the physical, chemical, and biological integrity of 

downstream waters and therefore have a significant nexus to (a)(1) through (3) 

waters. 

NAIOP Commercial Real Estate Development Association (Doc. #14621)

8.128 This definition utilizes the term “Ordinary High Water Mark” (OHWM). This phrase is 

inconsistently interpreted in the field. The lack of a manual instructing regulators and the 

regulated public as to what is an OHWM is the cause of most debates over whether or not 

a defined channel is a gulley, rill, non-wetland swale, or an ephemeral stream. For 

example, below is a picture of an “easy” OHWM determination. Some regulators would 

say the OHW elevation is the yellow line; others would pick the white line (it is the 

lower, yellow line – the OHWM is where that plane intersects the edge of the bank). 

Some regulators would say the OHW elevation is the yellow line; others would pick the white line (it is the lower, 

yellow line – the OHWM is where that plane intersects the edge of the bank).

It is critical for the Agencies to refine the field location protocols of OHWM so that it is 

clear as to the extents of such regulatory authority because the lack of specificity on this 

term for decades simply continues to build angst amongst the regulated public.

We have learned that the Corps has unveiled guidance aimed at clarifying OHWM. We 

recommend that these documents need to be developed for the U.S. before implementing 

a new regulation relying on a loosely defined term. (p. 6)
Clean Water Rule Response to Comments – Topic 8: Tributaries

343

Agency Response: Site-specific analysis of a particular OHWM call is beyond the 

scope of the rule. The final rule does not change the definition of or methods for 

identifying the OHWM. The agencies plan to continue to build on the more than a 

decade of effort spent improving the consistency and rigor of OHWM

identifications, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates. See also summary response 8.1.2 above.

South Carolina Forest Association (Doc. #6855)

8.129 We ask that EPA recognize that stream bank, bed, and OHW mark may be present with 

very low water flow, especially in areas with gullied and eroded channels from past land 

use. Some of these channels may flow less than 10% of the year. A discernable bed, 

banks, and OHW mark should not be used to define WOTUS. (p. 1)

Agency Response: The final rule continues the longstanding practice of using the 

OHWM to determine the lateral extent of jurisdiction for tributaries. Where the 

physical characteristics of bed and banks and another indicator of ordinary high 

water mark no longer exist or are actively manipulated, the presence of bed and 

banks and OHWM may be determined by using other appropriate means that 

consider the characteristics of the surrounding areas. The OHWM continues to be 

identified using indicators of regular high flows whose return interval varies across 

the country based on climate, hydrology, and other factors. The Final Rule contains 

exclusions for erosional features that do not meet the definition of tributary, such as 

gullies, rills, and non-wetlands swales. The agencies have concluded that flow of a 

sufficient volume, frequency, and duration create and maintain the physical 

characteristics of tributaries, such as bed and banks and another indicator of 

OHWM. The Connectivity Report supports the scientific conclusion that all features 

that meet this definition of tributary impact the physical, chemical, and biological 

integrity of downstream waters and therefore have a significant nexus to (a)(1) 

through (3) waters. 

Kansas Independent Oil & Gas Association (Doc. #12249)

8.130 The definition of "tributary" includes terms such as "bed and banks" and "ordinary high 

water mark" which raise more questions about interpretation than provide clarity. 

Whether these physical characteristics are de facto evidence of significant nexus is a 

question of fact. (p. 14)

Agency Response: The final rule continues the longstanding practice of using the 

OHWM to determine the lateral extent of jurisdiction for tributaries. The OHWM 

continues to be identified using indicators of regular high flows whose return 

interval varies across the country based on climate, hydrology, and other factors. 

The agencies have concluded that flow of a sufficient volume, frequency, and 

duration create and maintain the physical characteristics of tributaries, such as bed 

and banks and another indicator of OHWM. The Connectivity Report supports the 

scientific conclusion that all features that meet this definition of tributary impact the 
Clean Water Rule Response to Comments – Topic 8: Tributaries

344

physical, chemical, and biological integrity of downstream waters and therefore 

have a significant nexus to (a)(1) through (3) waters. 

Pennsylvania Coal Alliance (Doc. #13074)

8.131 ...Although not an exhaustive listing, the following types of questions would remain if 

the Proposed Rule is finalized, as currently written:

...d. OHWM – How should an OHWM be delineated and documented? OHWM limits 

can be influenced by uncharacteristically high rainfall events and are seasonably difficult 

to identify, opening the door to subjective interpretation and confusion. (p. 15)

Agency Response: The final rule does not change the definition of or methods for 

identifying the OHWM. The agencies plan to continue to build on the more than a 

decade of effort spent improving the consistency and rigor of OHWM 

identifications, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates. 

Enefit American Oil (Doc. #13438)

8.132 By USACE’s own admission, “OHWM delineation in non-perennial (i.e., intermittent 

and ephemeral) streams can be especially challenging.”361 To conclude that any feature 

containing an OHWM and bed and banks is a WoUS and therefore subject to jurisdiction 

under the CWA is to potentially expand regulatory reach far and wide in the western U.S. 

Further, to include all parts of a tributary that contain a bed, banks, and OHWM 

regardless of breaks in the same is to reach far inland in these ephemeral systems, well 

beyond any intent of Congress or the courts to regulate waters under the CWA.

If it is “especially challenging” to even delineate an OHWM in non-perennial systems, 

and an OHWM is one of the key parts of the proposed definition of a tributary, the 

agencies cannot broadly include all tributaries as WoUS... (p. 3)

Agency Response: The final rule continues the longstanding practice of using the 

OHWM to determine the lateral extent of jurisdiction for tributaries. The OHWM 

continues to be identified using indicators of regular high flows whose return 

interval varies across the country based on climate, hydrology, and other factors. 

The agencies have concluded that flow of a sufficient volume, frequency, and 

duration create and maintain the physical characteristics of tributaries, such as bed 

and banks and another indicator of OHWM. The Connectivity Report supports the 

scientific conclusion that all features that meet this definition of tributary impact the 

physical, chemical, and biological integrity of downstream waters and therefore 

have a significant nexus to (a)(1) through (3) waters. For a further discussion of the 

limits of CWA jurisdiction in regards to tributaries and the use of OHWM see the 

summary responses 8.1 and 8.1.2 and the TSD.

 

361 See Section 1. Introduction in Mersel and Lichvar. 2014. A guide to ordinary high water mark (OHWM)

delineation for non-perennial streams in the western mountains, valleys, and coast region of the United States.

ERDC/CRREL TR-14-13, prepared by the U.S. Army Engineer Research and Development Center.
Clean Water Rule Response to Comments – Topic 8: Tributaries

345

Arizona Mining Association (Doc. #13951)

8.133 1. Wholesale regulation of dry desert washes in the arid West ignores the unique features 

of arid landscapes and exceeds the EPA and Corps authority under the CWA: According 

to a recent Corps’ research study:

The Arid West is generally characterized by high temperatures, greater 

evaporation than precipitation rates, and flashy precipitation events. In the desert 

locations, evaporation rates can be as much as 15–20 times greater than 

precipitation because of the high temperatures, high wind velocity, and sparse 

cloud cover. Precipitation events throughout the region have large temporal and 

spatial variability. Often, the total rainfall for the year comes from a couple of 

thunderstorms; a single event may provide intense precipitation in one location 

and no precipitation a short distance away.

Ordinary High Flows and the Stage–Discharge Relationship in the Arid West Region, p. 

19 (Corps 2011). Rainfall events in the arid West are infrequent and the average annual 

precipitation amounts are significantly less than other areas in the country. For example, 

in Arizona’s lower desert lands, the average annual precipitation ranges from about 2 to 8 

inches a year, and ranges from about 5 to 15 inches for Arizona’s higher desert lands.362

The OHWM is an indicia of flow developed for and most defensible in humid climates. It 

cannot simply be adopted for and uniformly applied to arid systems. The Corps’ own 

studies state as much (as discussed below). Due to soil type, high temperatures, high 

evaporation rate, and lack of vegetative cover, the soils in the arid West are highly 

erodible. Consequently, the soils are subject to extensive cutting during single storm 

events, creating dense, crisscrossing areas of dry arroyos, washes, and other similar 

erosional features. These dry desert erosional features have the potential to carry water 

only briefly in direct response to flashy, but infrequent, precipitation events, and are dry 

the vast majority of the time.363 In essence, such features are more similar in function to 

land or uplands than to a water feature.364

By relying primarily on the OHWM as evidence of flow, and failing to identify any 

defensible limits to EPA and Corps jurisdiction, the proposed rule defines tributaries in a 

way that will include all dry desert washes in the arid West as categorically jurisdictional. 

This approach ignores common sense. Under current agency guidance, ephemeral washes 

in the arid West are only jurisdictional if they have a “significant nexus” to a TNW after 

consideration of hydrologic factors including volume, duration, and frequency of flow, 

 

362 See, e.g., Descriptions of Ecoregions of the United States, (Bailey, U.S. Forest Service, 1995) (see description of 

Tropical/Subtropical Desert Division (consisting of the Chihuahuan Semidesert Province and the American 

Semidesert and Desert Province), available at 

http://www.fs.fed.us/land/ecosysmgmt/colorimagemap/images/320.html); Western Regional Climate Center, 

PRISM Precipitation Maps: 1961-90 at http://www.wrcc.dri.edu/pcpn/westus_precip.gif.

363 “In addition, [the processes of channelized flow, sheetfloods, or debris flows] are active during only a small 

percentage of time, with no flow occurring in many watersheds in the Southwest more than 95% of the time.” 

Review of Ordinary High Water Mark Indicators for Delineating Arid Streams in the Southwestern United States, p. 

37 (Corps 2004).

364 In fact, the preamble to the proposed rule refers to such features in the arid West as “dry-land systems” (79 Fed. 

Reg. at 22202).
Clean Water Rule Response to Comments – Topic 8: Tributaries

346

proximity to the TNW, average annual rainfall, historic record of water flow, etc. The 

proposed rule does away with this important limitation on CWA jurisdiction for 

ephemeral washes, as well as the associated consideration of relevant hydrologic factors. 

(p. 7-8)

Agency Response: The final rule continues the longstanding practice of using the 

OHWM to determine the lateral extent of jurisdiction for tributaries. The OHWM 

continues to be identified using indicators of regular high flows whose return 

interval varies across the country based on climate, hydrology, and other factors. 

The agencies plan to continue to build on the more than a decade of effort spent 

improving the consistency and rigor of OHWM identifications, especially in the 

western US where two guidebooks for OHWM identification have already been 

developed, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates. The Arid West OHWM manual was developed to address 

the identified challenges in low-gradient, alluvial ephemeral/intermittent channel 

forms, by using other features associated with the limits of the active floodplain 

(channel), which are easily identified in the field, less variable over time, and 

statistically linked to the hydrologic and hydraulic parameters of ephemeral and 

intermittent arid channel forms, to support the traditional OHWM indicators. This 

method uses stream geomorphology and vegetation response to the dominant stream 

discharge and represents the most consistent and repeating pattern associated with 

“ordinary” events representing OHW. The agencies have concluded that flow of a 

sufficient volume, frequency, and duration create and maintain the physical 

characteristics of tributaries, such as bed and banks and another indicator of 

OHWM. As described in the summary response 8.1, for a feature to be 

jurisdictional as a tributary it must have bed and banks and an OHWM and flow 

directly or indirectly into a (a)(1) – (a)(3) water. The Connectivity Report supports 

the scientific conclusion that all features that meet this definition of tributary impact 

the physical, chemical, and biological integrity of downstream waters and therefore 

have a significant nexus to (a)(1) through (3) waters. For a further discussion of the 

limits of CWA jurisdiction in regards to tributaries and the use of OHWM see the 

summary responses 8.1, 8.1.1, 8.1.2 and the TSD.

8.134 3. Not all features with bed and banks and OHWM in the arid West will contribute flow 

to a TNW: The proposed rule suggests that having a bed and banks, combined with an 

OHWM, are evidence of flow and would not be present without flow. Thus, the rule 

suggests that these indicia establish that flow occurs, and because the agencies have not 

set any further criteria as to amount, duration or frequency of flow, the claimed indicia of 

flow will be used to define a tributary. The assumptions regarding the presence of beds 

and banks along with OHWMs, however, do not work in arid systems. First, because of 

the high erosion potential of arid landscapes and the infrequent but flashy storms that 

occur in these areas, erosional channels or cuts can appear during a single storm event 

and persist on the landscape even in the absence of any further flows. These erosional 

channels or cuts often will appear to have a distinguishable bed and banks and may have 

OHWM indicators, but are not evidence that the channels actually contribute flow to 

TNWs. The Corps has described this phenomenon as follows: “commonly observed 
Clean Water Rule Response to Comments – Topic 8: Tributaries

347

physical features [in the arid West] are potentially the result of uncommon processes and 

... the effects of the most common condition (channelized flow or no flow at all) do not 

persist on the landscape.” Review of Ordinary High Water Mark Indicators for 

Delineating Arid Streams in the Southwestern United States, p. 37 (Corps 2004). 

Consequently, in arid landscapes, what may appear to be ordinary physical characteristics 

on the land surface, such as the presence of an ephemeral wash, are not reliable indicators 

of a feature that will convey water in the future, but are solely an indicator that flow may 

have existed at one time in that discrete location.

In addition, because the presence of a bed and banks and OHWM indicators on a water 

feature in the arid West is typically the result of an unusual event, such physical 

characteristics are not representative of ordinary conditions. In fact, the Corps has 

recognized that because of the propensity for arid West erosional channels to respond to 

flashy storm events, “the actual location of the OHWM, the one that would be established 

if the [ephemeral feature] reached an equilibrium condition, should be considered to be at 

some point below the current position of the physical features normally associated with 

the OHWM.” Review of Ordinary High Water Mark Indicators for Delineating Arid 

Streams in the Southwestern United States, p. 77 (Corps 2004). Consequently, not only is 

the use of OHWM indicators in the arid West not indicative of the potential to contribute 

flow, such use also overstates the extent of what actually may be considered as OHWM.

Further, the OHWM is a humid system concept, and the Corps on numerous occasions 

has noted the challenge of applying the OHWM concept to ephemeral features in the arid 

West:

• “These factors [high ratio of peak to average annual discharges, rapid responses to 

rainfall] coupled with the highly variable climate and intense precipitation events, 

make selection of reliable OHWM field indicators [in the arid West] challenging.” 

Review of Ordinary High Water Mark Indicators for Delineating Arid Streams in 

the Southwestern United States, pp. 6-7 (Corps 2004).

• Precise location of the OHWM is especially difficult in arid regions where the 

morphological features present on the landscape are possibly the result of: flow 

events of various magnitude (e.g., high-flow and low-flow channels of compound 

channels); multiple processes (e.g., sheetfloods and streamflows on discontinuous 

ephemeral streams); or no longer active processes (e.g., channels abandoned by 

avulsion on alluvial fans and anastomosing streams). Review of Ordinary High 

Water Mark Indicators for Delineating Arid Streams in the Southwestern United 

States, p. 74 (Corps 2004).

• ”Unambiguous morphological features indicative of the OHWM are unlikely 

under these conditions since channel morphology is in a state of flux, with high 

water marks being constantly reworked.” Review of Ordinary High Water Mark 

Indicators for Delineating Arid Streams in the Southwestern United States, p. 60 

(Corps 2004).

• “In the arid West, channel morphology and, as a consequence, the physical 

features associated with OHWM are frequently the result of extreme floods or 

short-term, high intensity events.” Distribution of Ordinary High Water Mark 
Clean Water Rule Response to Comments – Topic 8: Tributaries

348

(OHWM) Indicators and Their Reliability in Identifying the Limits of “Waters of 

the United States” in Arid Southwestern Channels, p. 1 (Corps 2006).

• “OHWM indicators, originally intended to define the limits of OHW in tidal and 

navigable waters, are confounded by the drastic differences in the climate, 

geology, soil, and vegetation characteristics in which arid streams operate.” 

Distribution of Ordinary High Water Mark (OHWM) Indicators and Their 

Reliability in Identifying the Limits of “Waters of the United States” in Arid 

Southwestern Channels, p. 2 (Corps 2006).

• “With dominant, or effective, discharge in the arid west being 

“flashy”(intermittent and extreme), the overall response of the channel reflects 

these conditions. Likewise, the distribution of OHWM indicators follows a similar 

response to these regional conditions. There appears to be no direct correlation 

between the location of OHWM indicators and the inundation areas associated 

with specific recurrence interval flood events. The location of OHWM indicators 

seems to have two patterns: 1) 74% of the indicators are located within the 

bankfull and active floodplain channels and 2) the indicators are not associated 

with any return interval event or with physical channel features found in the 

field.” Distribution of Ordinary High Water Mark (OHWM) Indicators and Their 

Reliability in Identifying the Limits of “Waters of the United States” in Arid 

Southwestern Channels, p. 14 (Corps 2006).

• “The most problematic ordinary high water (OHW) delineations are associated 

with the commonly occurring ephemeral/intermittent channel forms that dominate 

the Arid West landscape. The climate of the region drastically influences the 

hydrology, channel-forming processes, and distribution of OHWM indicators 

such that delineations can be inconsistent (over space and time) and problematic.” 

A Field Guide to the Identification of the Ordinary High Water Mark (OHWM) in 

the Arid West Region of the Western United States, p. 1 (Corps 2008).

• “Establishing the extent of the OHWM is often difficult because of the variable 

conditions that the streams regularly endure. Arid streams are frequently impacted 

by short-term, high-intensity or “flashy” events that occur between periods of 

drought.” Vegetation and Channel Morphology Responses to Ordinary High 

Water Discharge Events in Arid West Stream Channels, p. 1 (Corps 2009). See 

also Ordinary High Flows and the Stage–Discharge Relationship in the Arid West 

Region, p. 1 (Corps 2011).

• “In this study we found no direct association between OHWM indicators and 

channel type or landscape position. These findings suggest that OHWM indicators 

are distributed randomly throughout the landscape and are not related to specific 

channel characteristics.” Survey of OHWM Indicator Distribution Patterns across 

Arid West Landscapes, p. 17 (Corps 2013).

Although application of the OHWM concept is likely a useful indicator in humid areas 

because it will represent equilibrium conditions and evidence of flow, application of the 

OHWM concept to ephemeral washes in the arid West is laced with uncertainty. Further, 

even if OHWM indicators can be identified for an ephemeral drainage, this does not 

mean that there is actual physical flow or evidence of any other type of potential 
Clean Water Rule Response to Comments – Topic 8: Tributaries

349

connection to potential downstream TNWs. Although presence of OHWM indicators 

may be one of many factors that could be considered in determining whether ephemeral 

drainages are jurisdictional, the agencies need to establish some bright lines as to 

magnitude, duration and frequency of flow, along with distance to a TNW, and other 

relevant factors such as potential chemical or biological connections. In the absence of 

such site-specific data demonstrating an actual meaningful connection between 

ephemeral drainages and the physical, chemical and biological integrity of TNWs, the 

agencies have no authority to attempt to apply their proposed definition of “tributary” to 

ephemeral drainages in the arid West. (p. 9-12)

Agency Response: See response to the above comment also from Arizona Mining 

Association (Doc. #13951) above, summary response 8.1.2 above, and TSD section 

7.A. 

Freeport-McMoRan Inc. (Doc. #14135, #14135.1 and #14135.2)

8.135 IV. Not all features in the arid west with a bed, banks, and ordinary high water 

mark will contribute flows to a traditional navigable water.

The Proposed Rule concludes that a bed, banks, and ordinary high water mark are the 

appropriate physical indicators of a tributary “because these features are generally 

physical indicators of flow.”365 Again, in the arid west, this conclusion is simply 

incorrect. In arid landscapes with highly erodible soils and minimal vegetation, such 

features can be formed by a single event and will be sustained for very long periods of 

time even if there is no additional flow.366 In general, the use of the ordinary high water 

mark is likely a sensible indicator because in humid landscapes it will represent an 

equilibrium condition.367 In contrast, in arid systems “what appear to be ‘ordinary’ 

conditions in fact most often reflect distant, historic events that neither represent 

contemporary conditions nor do they represent any sort of equilibrium conditions.”368 As 

detailed in the attached Technical Comments, the Corps’ own evaluations of the ordinary 

high water mark in the arid west demonstrates that there is no direct relationship between 

ordinary high water marks that exist on the landscape and the position and location of 

channels in response to rain events.369 Plainly, the “ordinary” high water marks on arid 

west lands do not convey any information about where stormwater will flow in the next 

rain event. Therefore, it is entirely possible that “ordinary” high water marks that exist 

today will not actually contribute flows to a traditional navigable water in a future storm 

event. In addition, even when flows may occur, these flows do not constitute “ordinary 

high water.”

The Science Advisory Board’s recent letter to EPA suggesting that the definition of 

tributary be modified to “bed, banks, and evidence of flow” offers no improvement in this 

 

365 79 Fed. Reg. at 22,202.

366 Technical Comments at 2.

367 Technical Comments at 7.

368 Id.

369 Id. at 7-10.
Clean Water Rule Response to Comments – Topic 8: Tributaries

350

regard.370 According to the SAB, this revised definition is appropriate because “[a]n 

ordinary high water mark may be absent in ephemeral streams within arid and semi-arid 

environments or low gradient landscapes where the flow of water is unlikely to cause an 

ordinary high water mark.”371 However, as the SAB correctly notes, “significant nexus” 

is a legal, not a technical term,372 and this proposed definition disregards the possibility 

that these characteristics may be present in gullies and rills in the arid west landscape. 

Were the Agencies to adopt the SAB’s proposed definition of “tributary” there would be 

absolutely no means by which to distinguish between jurisdictional tributaries and nonjurisdictional gullies and rills, leading to an inevitable overreach beyond the Agencies’ 

statutory authority under the Clean Water Act.

Even those channels that do convey water may not have a sustained hydrologic 

connection that continues all the way to the traditional navigable water that gives rise to 

the Proposed Rule’s assertion of jurisdiction. As explained in the attached Technical 

Comments, the channels found in the arid west tend to be “losing streams.” This means 

that much of the water that flows in these channels is lost to infiltration and evaporation 

before it travels a great distance.373 For example, in the portion of the Santa Cruz River 

evaluated in the technical comments, groundwater is on average 400 feet below the 

surface.374 As a result, even if there is flow in headwater tributaries, it is unlikely that 

such flow makes it all the way to the downstream traditional navigable water: it is more 

likely lost to groundwater infiltration. As a result, there is no surface flow to create a 

continuous hydrologic connection to the traditional navigable water. Where this is the 

case, the Proposed Rule’s assertion of jurisdiction based on the fact that “tributaries” 

contribute flow to traditional navigable waters is flawed in many arid west systems.

Furthermore, the “case study” of the San Pedro River does not represent most arid west 

channel systems. As set forth in the attached technical comments, the San Pedro River 

cannot be assumed to be a typical arid river system.375 First, the San Pedro River has 

geologic characteristics that are distinct from other river systems in the arid west that 

cause it to experience more runoff than other systems.376 Second, an analysis of the San 

Pedro River and the nearby Santa Cruz River—which drains a watershed of similar 

size—shows significant differences in river flows.377 Examining data from 1997 to 2013, 

the San Pedro River averages 104 days per year with no flow while the Santa Cruz River 

experiences 326 days with no flow.378 This more than three-fold difference in the number 

of no-flow days means that the San Pedro River system cannot possibly be representative 

of the nearby Santa Cruz for the purposes of establishing connectivity. An analysis of 

U.S. gauge data from other rivers with similar drainage areas in Arizona shows that the 

 

370 Letter from Dr. David T. Allen, Chair, Science Advisory Board, to Gina McCarthy, Administrator, U.S. EPA 

(Sept. 17, 2014), available at http://www.eenews.net/assets/2014/09/30/document_gw_03.pdf.

371 Id. at 2.

372 Id. at 4.

373 Technical Comments at 12.

374 Id. at 14.

375 Id. at 13.

376 Id. at 11.

377 Id. at 14.

378 Id. at 15.
Clean Water Rule Response to Comments – Topic 8: Tributaries

351

number of no-flow days ranges from 0 to 347,379 suggesting that the one-system-fits-all 

approach advanced in the Proposed Rule’s near-exclusive reliance on the San Pedro 

River System cannot be adequate to establish a significant nexus for “tributaries” across 

the arid west.

As a result the Agencies cannot base their conclusion that arid west channels act as 

tributaries that contribute flow to traditional navigable waters on study of the San Pedro 

River alone. To do so would be to regulate these features as tributaries based on a 

speculative and potentially insubstantial connection, in violation of the scope of Clean 

Water Act jurisdiction as articulated by Justice Kennedy in Rapanos. (Doc. #14135, p. 5-

6)

Agency Response: See response to the above comment from Arizona Mining 

Association (Doc. #13951) above, summary response 8.1.1 and 8.1.2 above, TSD 

section 7.A, and the final Connectivity Report sections 3 and B.5. 

8.136 1.2. High Water Marks Are Not “Ordinary” in Arid Landscapes: Distinguishing 

between tributaries and gullies is, at best, imprecise. In humid landscapes, we may 

identify the starting point of a tributary based on the location on the landscape where 

unique, aquatic, lotic (i.e., flowing water) processes begin to occur and characteristic 

stream biotic communities begin to appear.1 However, in arid landscapes, characteristic 

biotic communities and characteristic biochemical or other lotic processes are often 

lacking (discussed in detail below). Without characteristic biotic or chemical indicators, it 

is typical for regulatory agencies to use hydrologic and/or geomorphic indicators from 

which to estimate flow frequencies and durations. Again, this approach is useful in humid 

landscapes where the regularity of flows leaves “tell-tale” features on the landscape. 

However, as we will show below, in arid landscapes particularly at the upstream end of 

the channel network, flows are extremely variable and leave widely variable and difficult 

to discern features on the landscape. Developing hydrologic or geomorphic indicators 

from which to estimate flow regularity across the arid southwestern US is beyond the 

current state-of-the-science. As we will show below, arid channels are formed and bear 

the features of very infrequent hydrologic events; that is, channels are formed by nonnormal events and the high water marks are often not left by ordinary flows. In the 

proposed rule, this reference level of flows for active channels is defined as the ordinary 

high water mark (OHWM). Quite simply, the OHWM is a snapshot feature that may be 

relevant for humid landscapes, but is not relevant in arid landscapes. It does not establish 

that flow occurs with a frequency or duration sufficient to support jurisdiction. (Doc. 

#14135.1, p. 2)

Agency Response: See response to the above comment from Arizona Mining 

Association (Doc. #13951) above, summary response 8.1.2 above, and TSD section 

7.A. 

8.137 The problem is that the regulatory assumption for how the OHWM will be used, and its 

reality in arid landscapes, are diametrically opposed. The OHWM is defined as “the line 

on the shore established by the fluctuations of water and indicated by physical 

 

379 Id. at 12-13, 15.
Clean Water Rule Response to Comments – Topic 8: Tributaries

352

characteristics such as a clear natural line impressed on the bank, shelving, changes in the 

character of the soil, disruption of terrestrial vegetation or the presence of litter and 

debris.”380 Over the past decade, the Corps’ research laboratories have reviewed the 

literature to develop potential OHWM indicators for arid regions,381 developed a field 

guide for identifying OHWM in arid regions, and tested the viability of their OWHM 

indicators in the field.382 This development of indicators and their testing in arid regions 

has shown the difficulty in actual application. In one study of OHWM indicators 

conducted at the reach scale, Corps researchers reported that OHWM indicators had no 

correlation with any recurrence interval of flood events, nor were they associated with 

any physical geomorphic channel feature at the reach scale.383 A subsequent study by the 

Corps conducted at a broader scale concluded that, “In this study we found no direct 

association between OHWM indicators and channel type or position location. These 

findings suggest that OHWM indicators are distributed randomly throughout the 

landscape and are not related to specific channel characteristics.”384

Even when (or if) a consistent, diagnostic OHWM can be identified, that indicator would 

in fact be of an unusual event much larger than could be reasonably considered 

“ordinary.” Because arid channels are shaped by rare events, and are not reshaped by 

subsequent smaller events, the morphological features of a landscape inevitably represent 

rare, large, unordinary conditions. Or, as stated by the Corps (emphasis added): “Given 

that arid-region rivers generally respond to large floods by dramatically widening their 

banks, the limits of the geomorphically effective event will likely be much more 

extensive than the limits of a low-flow channel inset into a compound channel. 

Consequently, if the OHWM is set at the outer limits of the extreme event, the designated 

“waters” will encompass a much greater area than is occupied by more ordinary 

flows.”385 Or more directly related to defining and identifying OHWM indicators: 

“Therefore, the actual location of the OHWM, the one that would be established if the 

river reached an equilibrium condition, should be considered to be at some point below 

the current position of the physical features normally associated with the OHWM.”386

The physical features associated with the OHWM in arid regions will, in fact, be the 

result of extreme events, and thus not represent ordinary conditions. Quite simply, if a set 

of consistent, defensible OHWM features could be identified, that would correspond to 

an area beyond the realistic extent of jurisdictional waters. With respect to the proposed 

rule, an OHWM in arid landscapes cannot be used to assert a tributary; rather a consistent 

OHWM would potentially be the most extreme upstream limit to potential jurisdiction 

and not representative of ‘ordinary’ conditions. (Doc. #14135.1, p. 8-9)

 

380 CFR Part 328.3

381 See generally Lichvar and Wakeley, 2004

382 See generally Lefebvre, L., R. Lichvar, and K. Curtis, 2013. Survey of OHWM Indicator Distribution Patterns 

across Arid West Landscapes. ERDC/CRREL TR-13-2.

383 See generally Lichvar, R.W., D. Finnegan, M. Ericsson and W. Ochs, 2006. Distribution of Ordinary High Water

Mark (OHWM) Indicators and their Reliability in Identifying the Limits of “Waters of the United States” in Arid

Southwestern Channels. ERDC/CRREL TR-06-5.

384 Page 17 in Lefebvre et al., 2013.

385 Page 74 in Lichvar, R.W., and J.S. Wakeley, 2004.

386 Page 77 in Lichvar and Wakeley, 2004.
Clean Water Rule Response to Comments – Topic 8: Tributaries

353

Agency Response: See response to the above comment from Arizona Mining 

Association (Doc. #13951) above, summary response 8.1.2 above, and TSD section 

7.A. 

8.138 The Draft Proposed Rule defines jurisdictional ''tributaries" using the Corps definition of 

"ordinary high water mark."387 That concept---created for waters that are "navigable-infact"---is excessively broad as applied to the arid southwest where the land is crisscrossed 

with lines or cuts on the ground caused by water flow during infrequent but high intensity 

storms. The mere presence of physical signs that water flows across desert lands from 

time to time is insufficient to establish CWA jurisdiction. (Doc. #14135.2, p. 2)

Agency Response: The final rule continues the longstanding practice of using the 

OHWM to determine the lateral extent of jurisdiction for tributaries. The OHWM

continues to be identified using indicators of regular high flows whose return 

interval varies across the country based on climate, hydrology, and other factors. 

The agencies have concluded that flow of a sufficient volume, frequency, and 

duration create and maintain the physical characteristics of tributaries, such as bed 

and banks and another indicator of OHWM. The Connectivity Report supports the 

scientific conclusion that all features that meet this definition of tributary impact the 

physical, chemical, and biological integrity of downstream waters and therefore 

have a significant nexus to (a)(1) through (3) waters. For a further discussion of the 

limits of CWA jurisdiction in regards to tributaries and the use of OHWM see the 

summary responses 8.1 and 8.1.2 and the TSD. 

Wyoming Mining Association (Doc. #14460)

8.139 ...Corps experts have said that the term OHWM is one of the most inconsistent and 

unclear terms in the CWA regulations.388 The proposed rule provides no further 

clarification regarding the term OHWM and as such will only lend further uncertainty in 

the delineation of tributaries. The current definition is problematic as many of the 

physical indicators used to define the OHWM may occur wherever land has water 

flowing across it, regardless of frequency or duration. Many of the indicators (e.g., 

changes in character of the soil, destruction of native terrestrial vegetation, presence of 

litter and debris) can be observed in very small drainages and even in upland areas far 

removed from actual waterways, especially in arid areas in Wyoming. (p. 5-6)

Agency Response: The final rule continues the longstanding practice of using the 

OHWM to determine the lateral extent of jurisdiction for tributaries. The OHWM 

continues to be identified using indicators of regular high flows whose return 

interval varies across the country based on climate, hydrology, and other factors. 

The agencies have concluded that flow of a sufficient volume, frequency, and 

duration create and maintain the physical characteristics of tributaries, such as bed 

and banks and another indicator of OHWM. The Connectivity Report supports the 

scientific conclusion that all features that meet this definition of tributary impact the 

 

387 33 C.F.R. § 328.3(e).

388 Mathew K. Mersel, U.S. Army Corps of Engineers, Cold Regions Research arid Engineering Laboratory, 

Development of National OHWM Delineation Technical Guidance (Mar. 4, 2014)
Clean Water Rule Response to Comments – Topic 8: Tributaries

354

physical, chemical, and biological integrity of downstream waters and therefore 

have a significant nexus to (a)(1) through (3) waters. For a further discussion of the 

limits of CWA jurisdiction in regards to tributaries and the use of OHWM see 

summary response 8.1 and 8.1.2 above and the TSD.

Devon Energy Corporation (Doc. #14916)

8.140 ...the Corps has been developing guidance on identifying an Ordinary High Water Mark 

(“OHWM”) that historically has defined the lateral extent of the federal jurisdiction in 

non-tidal WOTUS. OHWM is now used as criteria in defining a tributary in the Proposed 

Rule. While OHWM provides some degree of technical guidance, the Corps also 

recognizes that OHWM is a vague definition leading to inconsistent interpretations. Also 

as previously mentioned, an OHWM can be found in many ephemeral streams and 

therefore its use is inconsistent with the plurality imitation of jurisdiction to relatively 

permanent streams. So if OHWM remains as criteria to establish WOTUS, then it must 

be used in combination with the presence of both a define bed and bank to allow for a 

more correct application of the opinions in the Rapanos majority. In addition, Devon 

recommends that OHWM should generally be represented by a physical mark on the 

landscape. OHWM should be fairly stable over time and should have water in it at the 

high water mark level at a “1.5 or 2 year return interval as suggested by the Corps 

Engineer Research and Development Center389. (p. 5-6)

Agency Response: The final rule clearly requires the presence of both bed and 

banks and another indicator of OHWM, if one is not present then the water cannot 

qualify as a tributary. The final rule also does not change the definition or alter the 

methods for identification of OHWM. The OHWM continues to be identified using 

indicators of regular high flows whose return interval varies across the country 

based on climate, hydrology, and other factors.

National Mining Association (Doc. #15059)

8.141 To the extent the Agencies move forward with the current proposal, they must adopt the 

following changes in any final rule:

... 6) The Agencies should revise their approach to ephemeral waters by:

...

d. Making the August 2014 OHWM guidance documents390 part of the present 

rulemaking and providing the public with the opportunity for comment prior to the 

promulgation of any final “waters of the United States” rule in light of the potential 

implications those documents will have on the implementation of the rule and the scope 

of CWA jurisdiction.

... (p. 3, 5, 6)

 

389 Presentation by Matthew K. Mersel, U.S. Army Engineer Research and Development Center, Development of

National OHWM Delineation Technical Guidance (March 4, 2014).

390 Id. and also Mersel K. Matthew, et al., August 2014, “A Review of Land and Stream Classifications in Support of 

Developing a National Ordinary High Water Mark (OHWM) Classification.”
Clean Water Rule Response to Comments – Topic 8: Tributaries

355

Agency Response: The final rule also does not change the definition or alter the 

methods for identification of OHWM. The OHWM continues to be identified using 

indicators of regular high flows whose return interval varies across the country 

based on climate, hydrology, and other factors. The agencies plan to continue to 

build on the more than a decade of effort spent improving the consistency and rigor 

of OHWM identifications, especially in the western US where two guidebooks for 

OHWM identification have already been developed, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates.

National Sustainable Agriculture Coalition (Doc. #15403)

8.142 The proposed rule defines ordinary high water mark (OHWM) by reference only391, 

directing readers to 33 CFR 328.3(e) and the following definition:

“The term ordinary high water mark means that line on the shore established by 

the fluctuations of water and indicated by physical characteristics such as clear, 

natural line impressed on the bank, shelving, changes in the character of soil, 

destruction of terrestrial vegetation, the presence of litter and debris, or other 

appropriate means that consider the characteristics of the surrounding areas.”392

The EPA and the Corps should incorporate this definition into the proposed rule. Failing 

to include this definition in the rule requires readers to dig deeper for a term that is 

integral to the rule’s implementation—an unnecessary hoop through which the regulated 

community must jump. This simple solution reiterates and solidifies one of the criteria for 

the definition of tributary, and could help alleviate the regulated community’s concerns 

that temporary, precipitation-induced hydrologic features lacking an OHWM would be 

jurisdictional.

Recommendation: Include the definition of ordinary high water mark in the proposed rule 

to provide greater clarity and easier access to key terms. (p. 3-4)

Agency Response: As the commenter recommends, the final rule adds the 

definition of OHWM that existed in Corps regulations to EPA regulations. 

Halliburton Energy Services, Inc. (Doc. #15509)

8.143 ...the notion that using the OHWM as a defining characteristic provides clarity is belied 

by the difficulty that actually exists in the field in defining features with an OHWM.393

Similarly, while an exemption for gullies, swales and other erosional features is provided, 

the challenges of distinguishing these features from ephemeral streams - challenges 

acknowledged by the Agencies - further support the position that ephemeral streams 

 

391 Proposed Rule at 77.

392 33 C.F.R. § 328.3(e).

393 See e.g., Matthew K. Mersel and Robert W. Lichvar, U.S. Army Engineer Research and Development Center , A

Guide to Ordinary High Water Mark Delineation in Non-Perennial Streams in the Western Mountains, Valley and

Coast Region of the United States (August 2014) at p. 1-2 ("OHWM delineation in non-perennial [i.e., intermittent

and ephemeral] streams can be especially challenging.").
Clean Water Rule Response to Comments – Topic 8: Tributaries

356

should not automatically be jurisdictional. Moving a fuzzy line "upstream" to cover more 

landscape features under federal jurisdiction does nothing to provide greater clarity for 

the regulated community but does create more process and regulatory burden for 

landowners and businesses without any assurance of meaningful environmental benefit. 

(p. 4)

Agency Response: The final rule includes several changes to provide the 

additional clarity requested. The changes include identifying the specific functions 

to be accessed in a significant nexus evaluation, providing more exclusions as part of 

the rule text for the first time, and reducing the number of case-specific 

determinations of jurisdiction required. The final rule clearly requires the presence 

of both bed and banks and another indicator of OHWM, if one is not present then 

the water cannot qualify as a tributary. The final rule also does not change the 

definition or alter the methods for identification of OHWM. The OHWM continues 

to be identified using indicators of regular high flows whose return interval varies 

across the country based on climate, hydrology, and other factors. For a further 

discussion of the limits of CWA jurisdiction in regards to tributaries and the use of 

OHWM see the summary responses 8.1 and 8.1.2 and the TSD.

Pennsylvania Grade Crude Oil Coalition (Doc. #15773)

8.144 How will an OHWM be determined? Delineation of OHWM is open to subjective 

interpretation. The identification of the OHWM limits will be influenced by 

uncharacteristically high rainfall events and are seasonably difficult to identify. (p. 10)

Agency Response: The final rule also does not change the definition or alter the 

methods for identification of OHWM. The OHWM continues to be identified using 

indicators of regular high flows whose return interval varies across the country 

based on climate, hydrology, and other factors. The agencies plan to continue to 

build on the more than a decade of effort spent improving the consistency and rigor 

of OHWM identifications, especially in the western US where two guidebooks for 

OHWM identification have already been developed, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates. 

Dominion Resources Services, Inc. (Doc. #16338)

8.145 ...To the extent the agencies move forward with the proposal, we make the following 

recommendations:

...

 The proposed definition of “tributary” relies on the term “ordinary high water 

mark” (OHWM). The current definition of OHWM is unclear and has led to 

inconsistent interpretations in the field. While the Corps has recently issued 

guidance regarding the definition of OHWM questions remain regarding the 

consistency of this guidance with the regulatory definition of OHWM in 33 CFR 

328.3(e). With the inclusion of all tributaries as WOTUS, the definition of 

OHWM must be further clarified in order to provide consistency and certainty. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

357

We request that prior to completion of any rulemaking, the Corps finalize revised 

guidance regarding the determination of “ordinary high water mark” that is 

consistent with the regulatory definition in 33 CFR 328.3(e) and considers the 

term’s use in the definition of “tributary”. (p. 8)

Agency Response: The final rule also does not change the definition or alter the 

methods for identification of OHWM. The OHWM continues to be identified using 

indicators of regular high flows whose return interval varies across the country 

based on climate, hydrology, and other factors. The agencies plan to continue to 

build on the more than a decade of effort spent improving the consistency and rigor 

of OHWM identifications, especially in the western US where two guidebooks for 

OHWM identification have already been developed, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates. 

Washington Cattlemen’s Association (Doc. #3723)

8.146 The WCA disagrees with the EPA's definition of a "tributary". The WCA believes that 

the EPA should not have the ability or the authority to regulate a water body if EPA 

deems there is a "bed, bank and an ordinary high water mark. The CWA was never 

intended to allow the Federal Government to have authority over intermittent or 

ephemeral streams. (p. 3)

Agency Response: See the summary agency responses 8.1, 8.1.1, and 8.1.2 for 

details on the agencies long standing practices and authorities regulating 

intermittent and ephemeral streams. 

Oregon Cattlemen’s Association (Doc. #5273.1)

8.147 By including the caveat that "tributaries" do not necessarily feature a bed, banks, and

ordinary high water mark, the Agencies have extended its definition beyond its natural 

meaning. At a minimum, the Agencies should modify its proposed definition of 

"tributary" to reflect the natural definition of the word. (p. 4)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. The final rule clearly 

requires the presence of both bed and banks and another indicator of OHWM, if 

one is not present then the water does not qualify as a tributary. Wetlands, lakes, 

ponds, and other features lacking a bed and banks and/or OHWM are no longer 

defined as tributaries in the Final Rule, but may be considered jurisdictional 

“waters of the United States” as adjacent waters or similarly situated waters with a 

significant nexus to (a)(1) through (3) waters. 

National Farmers Union (Doc. #6249)

8.148 The proposed rule defines " tributary" as "a water physically characterized by the 

presence of a bed and banks and ordinary high water mark...which contributes flow, 

either directly or through another water, to a water identified in paragraphs (a)(l) through 

(4) of this section." In order to provide more clarity to the regulated community, the 
Clean Water Rule Response to Comments – Topic 8: Tributaries

358

agencies should note in the final rule that these features take years to form. This should 

mitigate concern that temporary accumulations directly related to isolated rain events will 

be considered jurisdictional. The agencies should add further clarifying language, 

including but not limited to descriptive examples of water and events that are not 

considered tributaries, in the final rule in order to ensure these distinctions are well 

understood in the regulated community.

The preamble notes that existing Corps regulations define the ordinary high water mark 

(OHWM) "as the line on the shore established by fluctuations of water and indicated by 

physical characteristics such as a clear, natural line impressed on the banks, shelving, 

changes in the character of soil, destruction of terrestrial vegetation, the presence of litter 

and debris, or other appropriate means that consider the characteristics of the surrounding 

areas. 33 CFR 328.3(e)." The agencies should incorporate this definition within the final 

rule so that the regulated community can refer to one place for as much of the 

information that is needed to maintain compliance as possible. 

These points should ensure that the definition of "tributary" in the proposed rule will not 

bring any water into jurisdiction that would not be found jurisdictional under the 

"significant nexus" test that is applied to "other waters." If incorporated, they would 

create regulatory certainty and lessen administrative burden by settling jurisdiction for 

waters that would have been subject to a case-by-case determination but ultimately found 

jurisdictional. (p. 3)

Agency Response: As the commenter recommends, the final rule adds the 

definition of OHWM that existed in Corps regulations to EPA regulations. The final 

rule also clearly requires the presence of both bed and banks and another indicator 

of OHWM, if one is not present then the water does not qualify as a tributary. The 

Final Rule also contains exclusions for erosional features that do not meet the 

definition of tributary, such as gullies, rills, and non-wetlands swales.

Alameda County Cattlewomen (Doc. #8674)

8.149 The agencies have excluded consideration of flow, making the definition completely 

dependent on land features, not actual water. And even with regard to the land features, 

the agencies contradict themselves. The agencies state that a tributary needs a bed, bank 

and OHWM but then turned around in the next sentence and contradicted themselves, 

saying that in fact a regulator does NOT need to find a bed, bank or OHWM to find a 

jurisdictional tributary. (Proposed Rule at 22241). Again, these contradictions only 

provide added confusion. (p. 8)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. The final rule clearly 

requires the presence of both bed and banks and another indicator of OHWM, if 

one is not present then the water does not qualify as a tributary. Wetlands, lakes, 

ponds, and other features lacking a bed and banks and/or OHWM are no longer 

defined as tributaries in the Final Rule, but may be considered jurisdictional 

“waters of the United States” as adjacent waters or similarly situated waters with a 

significant nexus to (a)(1) through (3) waters. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

359

8.150 ...considering the confusion and inconsistent application of distinguishing an OHWM, as 

noted by Justice Kennedy in Rapanos, making this distinction is not helpful.394 The 

agencies cannot include an indicator like OHWM that is inconsistently applied and can 

change as a matter of policy without notice and comment. Most recently, the Corps 

released new guidance documents for determining OHWM.395 If the definition and 

determination can be so easily changed without public input, it provides little clarity and 

certainty to the regulated community. ACCW request the agencies recognize that OHWM 

is not an adequate indicator, ephemeral drainages can be recognized as gullies by many 

livestock producers and the agencies should include all such features in their definition of 

excluded gullies. (p. 11)

Agency Response: The final rule clearly requires the presence of both bed and 

banks and another indicator of OHWM, if one is not present then the water does 

not qualify as a tributary. Bed and banks can be naturally formed by repeated flow 

of water or artificially constructed out of rock, concrete, etc, however both bed and 

banks and another indicator of OHWM must be found before a water can be called 

a tributary under the rule. The Corps and EPA plan to continue to build on the 

more than a decade of effort spent improving the consistency and rigor of OHWM 

identifications, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates. The agencies have concluded that flow of a sufficient 

volume, frequency, and duration create and maintain the physical characteristics of 

tributaries, such as bed and banks and another indicator of OHWM. The 

Connectivity Report supports the scientific conclusion that all features that meet 

this definition of tributary impact the physical, chemical, and biological integrity of 

downstream waters and therefore have a significant nexus to (a)(1) through (3) 

waters. While the Rule does contain exclusions for ephemeral features that do not 

meet the definition of tributary, such as gullies, rills, and non-wetland swales, 

ephemeral waters that have the physical characteristics of a tributary, including bed 

and banks and OHWM, are not excluded from jurisdiction. The preamble to the 

final rule and the Compendium 7 provide in depth discussion of each of the 

exclusions.

 

394 Rapanos, J. Kennedy, at 24 (In describing the application of the Corps’ OHWM criteria, “[a]ssuming it is subject

to reasonably consistent application, but see U.S. General Accounting Office, Report to the Chairman,

Subcommittee on Energy Policy, Natural Resources and Regulating Affairs, Committee on Reform, House of

Representatives, Waters and Wetlands: Corps of Engineers Needs to Evaluate Its District Office Practices in

Determining Jurisdiction, GAO-04-297 pp. 3—4 (Feb. 2004), http://www.gao.gov/new.intems/d04297.pdf (noting

variation in results among Corps district offices)”). 

395 U.S. Army Corps of Engineers, A Guide to Ordinary High Water Mark (OHWM) Delineation for Non-Perennial

Streams in the Western Mountains, Valleys, and Coast Region of the United States, August 2014 (available at

http://acwc.sdp.sirsi.net/client/search/asset/1036027; U.S. Army Engineers, A Review of Land and Stream

Classifications in Support of Developing a National Ordinary High Water Mark (OHWM) Classification, August

2014 (available at http://acwc.sdp.sirsi.net/client/search/asset/1036026). 
Clean Water Rule Response to Comments – Topic 8: Tributaries

360

Glenn County Rangeland Association (Doc. #12724)

8.151 ...the proposed definition of "tributary" that includes anything connected to otherwise 

jurisdictional water that has a bed, bank and ordinary high water mark (OHWM) is so 

vague it can be interpreted just about any way one wishes on the ground in rangeland 

areas. On rangeland, there usually are no established OHWMs. Almost all water flow at 

best, are seasonal and intermittent. (p. 1)

Agency Response: See responses to the two comments from Alameda County 

Cattlewomen (Doc. #8674) above and summary response 8.1.2 above. 

Colorado Farm Bureau (Doc. #12829)

8.152 The Agencies have proposed an overly broad "tributary" definition focusing on the 

presence of a bed, bank, ordinary high water mark (OHWM) and any minimal amount of 

flow that eventually reaches (directly or through any number of other paths and channels) 

to a creek or stream that in turn ultimately flows to a traditional navigable water. See 79 

Fed. Reg. at 22,263.396 The terms "bed" and "bank" simply mean land with lower 

elevation in between lands of higher elevation. This includes land with only subtle 

changes in elevation-any land where rainwater naturally channels as it flows downhill. 

All but the flattest terrain will have natural paths of lower elevations that water will 

follow. (p. 6)

Agency Response: See responses to the two comments from Alameda County 

Cattlewomen (Doc. #8674) above and summary response 8.1.2 above. In addition the 

terms bed and banks have been further explained in the preamble. 

Bayless and Berkalew Co. (Doc. #12967)

8.153 The rule is ambiguous with overly broad definitions which contradict the 

agricultural exemptions.

The definition of "tributary" in the proposed rule is very broad to include any feature with 

a bed and bank and ordinary high water mark that contributes flow in any amount either 

directly or through ditches - the amount, frequency, or duration of flow does not limit the 

definition...The mere presence of gravity and slope results in every flood event in 

Arizona, no matter how significant, as likely to leave a high water mark and every 

"tributary" either connecting directly or indirectly to another water at some point in time. 

(p. 2-3)

Agency Response: The final rule clearly requires the presence of both bed and 

banks and another indicator of OHWM, if one is not present then the water does 

not qualify as a tributary. The agencies have concluded that flow of a sufficient 

volume, frequency, and duration create and maintain the physical characteristics of 

tributaries, such as bed and banks and another indicator of OHWM. The 

Connectivity Report supports the scientific conclusion that all features that meet 

 

396 The rule would provide: “The term tributary means a water physically characterized by the presence of a bed and 

banks and ordinary high water mark, as defined at 33 CFR 328.3(e), which contributes flow, either directly or 

through another water, to a water identified in paragraphs (a)(1) through (4) of this section.”
Clean Water Rule Response to Comments – Topic 8: Tributaries

361

this definition of tributary impact the physical, chemical, and biological integrity of 

downstream waters and therefore have a significant nexus to (a)(1) through (3) 

waters. While the Rule does contain exclusions for ephemeral features that do not 

meet the definition of tributary, such as gullies, rills, and non-wetland swales, 

ephemeral waters that have the physical characteristics of a tributary, including bed 

and banks and OHWM, are not excluded from jurisdiction. The preamble to the 

final rule and the Exclusion Compendium provide in depth discussion of each of the 

exclusions.

North American Meat Association and American Meat Institute (Doc. #13071)

8.154 The proposed definition of tributary is problematic because it relies on vague language 

and confusing concepts. Specifically, the definition is tied to the OHWM. Numerous 

experts, including some from the Corps, have stated that OHWM is an inconsistent and 

ambiguous term.397 Inconsistent interpretations have led to varying indicators and 

delineation practices in the field.

398 The proposed rule offers nothing new regarding 

OHWM, which is problematic because many OHWM physical indicators can occur 

wherever land may have water flowing across it, regardless of frequency or duration. 

OHWM indicators can be found in small drainages and upland areas, especially in arid 

areas.

399 The proposed definition of "tributary" cannot provide the clarity the agencies 

assert when the OHWM concept is a well-known source of confusion for regulators. (p. 

6)

Agency Response: See responses to the two comments from Alameda County 

Cattlewomen (Doc. #8674) above and summary response 8.1.2 above.

National Chicken Council, National Turkey Federation, and U.S. Poultry & Egg Association 

(Doc. #14469)

8.155 In defining a tributary as a drainage feature having a bed, bank and an ordinary high 

water mark (OHWM), the agencies want the public to believe that the assertion of CWA 

authority over “tributaries” is appropriate. This assertion fails to recognize the 

unnecessary inclusion of numerous other land features that fall within the definition of 

“tributary,” such as those areas with drainage features that do not resemble any stream, 

brook or creek. Instead, the agencies advance new jurisdictional authority by introducing 

ambiguity and vague concepts of connectivity. The agencies justify this effort to broaden 

the boundaries of what the agencies consider a tributary because in “some regions of the 

 

397 Matthew K. Mersel, U.S. Army Corps of Engineers, Cold Regions Research and Engineering Laboratory, 

Development of National OHWM Delineation Technical Guidance (Mar. 4, 2014), available at 

http://insideepa.com//index.php?option=com_iwpfile&file=apr2014/epa2014_0760.pdf.

398 The OHWM standard is so confusing that the agencies are planning to issue guidance to redefine OHWM metrics 

and standardize the concept’s implementation. Bridget DiCosmo, InsideEPA.com, Agencies’ Workgroup Eyes 

Changes to Key Delineation Guides (Apr. 30, 2014). But revision of OHWM—a fundamental term for the proposed 

tributary definition—should be part of this proposed rulemaking, not done as part of a separate guidance without 

public involvement.

399 U.S. Army Corps of Engineers, A Field Guide to the Identification of the Ordinary High Water Mark (OHWM) 

in the Arid West Region of the Western United States, at 20 (Lichvar and McColley 2008), available at 

http://www.dtic.milldtic/tr/fulltext/u2/a486603.pdf. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

362

country where there is a very low gradient, the banks of a tributary may be very low or 

may even disappear at times.” 79 Fed. Reg. at 22202. This appears to be a thinly veiled 

justification to protect human health and the environment, without first demonstrating 

any harm that must be eliminated or prevented. (p. 5)

Agency Response: See responses to the two comments from Alameda County 

Cattlewomen (Doc. #8674) above and summary response 8.1.2 above.

Minnesota Farm Bureau (Doc. #14653)

8.156 Minnesota Farm Bureau has significant concerns with the limitless jurisdiction the 

proposed rule provides the Agencies. Specifically,

...

 ...the rule uses the unclear concept of ordinary high water mark, as well as bed 

and bank, as the key identifiers for tributaries. This would include land with only 

subtle changes in elevation, where any land where rainwater naturally channels as 

it flows downhill;... (p. 2)

Agency Response: See responses to the two comments from Alameda County 

Cattlewomen (Doc. #8674) above and summary response 8.1.2 above.

Irvine Ranch Water District (Doc. #14774)

8.157 The proposed rule, in making all adjacent waters jurisdictional by rule, will have the 

unintended consequence of greatly expanding federal jurisdiction and result in widely 

varied applications of the rule. The term "neighboring" defines adjacent waters to include 

riparian areas, bed and bank, and/or floodplains. This differs substantially from the Corps 

traditional jurisdiction of an ordinary high water mark. IRWD asks that the Corps' 

jurisdiction of an ordinary high water mark specifically be retained to determine 

what features are or are not jurisdictional instead of a broad definition that covers 

multiple types of features that may or may not have an ordinary high water mark. 

The rule notes that uplands within floodplains are never WOTUS, but without 

requiring the physical presence of a defined ordinary high water mark, 

jurisdictional areas could easily be expanded.

Furthermore, the entire structure of the Corps' permitting process is based on the concept 

of an ordinary high water mark. IRWD cautions that to the extent CWA jurisdiction is 

broadened, either by rule or by practice, the Nationwide Permit Program could be 

rendered useless. We are also concerned that the proposed rule's changes could expand 

the limit of the Corps' jurisdiction to include the bed and bank of a channel, tributaries 

that do not have an ordinary high water mark, neighboring waters that do not have an 

ordinary high water mark, areas with adjacent riparian vegetation, and areas within a 

mapped floodplain. The Corps' traditional jurisdiction should be retained, which was the 

goal of the proposed rule. The proposed rule should be amended to ensure that it will not 

unintentionally broaden federal jurisdiction. (p. 5-6)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. The final rule clearly 

requires the presence of both bed and banks and another indicator of OHWM, if 
Clean Water Rule Response to Comments – Topic 8: Tributaries

363

one is not present then the water does not qualify as a tributary. Wetlands, lakes, 

ponds, and other features lacking a bed and banks and/or OHWM are no longer 

defined as tributaries in the Final Rule, but may be considered jurisdictional 

“waters of the United States” as adjacent waters or similarly situated waters with a 

significant nexus to (a)(1) through (3) waters. 

California Association of Winegrape Growers (Doc. #14593)

8.158 B. Improper Expansive Interpretation of the Tributaries Standard

The Proposed Rule categorically asserts jurisdiction broadly over all tributaries with no 

site-specific analysis required. By rule, anything with a bed, bank, and ordinary high 

water mar which may directly or indirectly contribute flow to a jurisdictional water, 

without regard to its impact on downstream waters. Further, again by rule, wetlands, 

lakes, and ponds are tributaries even if they lack beds, banks, or ordinary high water 

marks. (79 Fed. Reg. 22201 (April 21, 2014.) The Agencies’ decision to use the presence 

of an ordinary high water mark as one of the factors for considering a water to be a 

tributary under Kennedy’s standard is directly counter to Kennedy’s clear directive. 

Kennedy clearly stated:

As noted earlier, the Corps deems a water a tributary if it feeds into a traditional 

navigable water (or a tributary thereof) and possesses an ordinary high-water mark, 

defined as a “line on the shore established by the fluctuations of water and indicated by 

[certain] physical characteristics,” § 328.3(e). This standard presumably provides a rough 

measure of the volume and regularity of flow. Assuming it is subject to reasonably 

consistent application, it may well provide a reasonable measure of whether specific 

minor tributaries bear a sufficient nexus with other regulated waters to constitute 

“navigable waters” under the Act. Yet the breadth of this standard--which seems to leave 

wide room for regulation of drains, ditches, and streams remote from any navigable-infact water and carrying only minor water volumes toward it--precludes its adoption as 

the determinative measure of whether adjacent wetlands are likely to play an important 

role in the integrity of an aquatic system comprising navigable waters as traditionally 

understood. Indeed, in many cases wetlands adjacent to tributaries covered by this 

standard might appear little more related to navigable-in-fact waters than were the 

isolated ponds held to fall beyond the Act's scope in SWANCC. (Rapanos, supra, at 780-

782, citations omitted, emphasis added.)

As evidenced in the above language, Kennedy determined that the inconsistent 

application of the ordinary high-water mark precludes its use as a factor for determining 

if a waterbody meets the definition of a tributary. (Ibid.) By disregarding the directive, 

the Proposed Rule’s reliance on the ordinary high-water mark is not a reasonable measure 

of whether a tributary processes a significant nexus with a traditional navigable water. (p. 

10-11)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. The final rule clearly 

requires the presence of both bed and banks and another indicator of OHWM, if 

one is not present then the water does not qualify as a tributary. Wetlands, lakes, 

ponds, and other features lacking a bed and banks and/or OHWM are no longer 
Clean Water Rule Response to Comments – Topic 8: Tributaries

364

defined as tributaries in the Final Rule, but may be considered jurisdictional 

“waters of the United States” as adjacent waters or similarly situated waters with a 

significant nexus to (a)(1) through (3) waters. The Connectivity Report supports the 

scientific conclusion that all features that meet this definition of tributary impact the 

physical, chemical, and biological integrity of downstream waters and therefore 

have a significant nexus to (a)(1) through (3) waters. For a further discussion of the 

limits of CWA jurisdiction in regards to tributaries and the use of OHWM see the 

summary response 8.1 at the start of this compendium and the TSD.

Monarch-Chesterfield Levee District, St. Louis, Missouri (Doc. #14904)

8.159 b. The definition proposed for "tributary" creates uncertainty and relies on newly 

released Technical guidance for identifying tributaries.

The proposed definition of "tributary" — which requires only a bed, banks and an 

ordinary high water mark ("OHWM") — will create uncertainty in many instances. While 

a bed, banks and OHWM can be easily identified in some locations, in others those 

features are not evident, especially an OHWM. The proposed rule would nevertheless 

make a tributary a "waters of the U.S." if, at any upstream location, a bed, banks and 

OHWM can be identified. Such a broad definition will potentially require examination of 

miles of upstream tributary features, quite possibly beyond areas that are accessible either 

due to legal or physical constraints. The proposed rule's reliance on being able to define 

and identify an OHWM to determine jurisdiction over tributaries does not provide clarity 

as there has not been established a reliable and repeatable means to identify an OWHM. 

Just shortly after the proposed rule was published in April 2014, the Corps of Engineers 

released new technical guidance (ERDC/CCREL TR-14-13, A Guide to Ordinary High 

Water Mark (OHWM) Delineation for Non-Perennial Streams in the Western Mountains, 

Valleys, and Coast Region of the United States) for delineating the OHWM in nonperennial streams in the Western U.S. The EPA has stated publicly that similar guidance 

is being developed for other regions. The Corps also released in August 2014, 

(ERDC/CCREL TR-14- 12, A Review of Land and Stream Classifications in Support of 

Developing a National Ordinary High Water Mark (011WM Classification) a report with 

the objective of determining the "most appropriate factors to include in a national 

OHWM classification." As the factors to be used in identifying OHWM's have yet to be 

determined it is blatantly false to claim that the proposed rule provides clarification and 

does not expand jurisdiction. (p. 3-4)

Agency Response: The final rule continues the longstanding practice of using the 

OHWM to determine the lateral extent of jurisdiction for tributaries. The final rule 

does not change the definition or alter the methods for identification of OHWM. 

The OHWM continues to be identified using indicators of regular high flows whose 

return interval varies across the country based on climate, hydrology, and other 

factors. The Corps and EPA plan to continue to build on the more than a decade of 

effort spent improving the consistency and rigor of OHWM identifications, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates. The documents identified in the comment were developed 

to help the public and field staff understand location site conditions and consistently 
Clean Water Rule Response to Comments – Topic 8: Tributaries

365

identify the OHWM. The agencies have concluded that flow of a sufficient volume, 

frequency, and duration create and maintain the physical characteristics of 

tributaries, such as bed and banks and another indicator of OHWM. The 

Connectivity Report supports the scientific conclusion that all features that meet 

this definition of tributary impact the physical, chemical, and biological integrity of 

downstream waters and therefore have a significant nexus to (a)(1) through (3) 

waters.

North Carolina Farm Bureau Federation (Doc. #15078)

8.160 The terms "bed" and "bank" simply mean land with lower elevation in between lands of 

higher elevation. This includes land with only subtle changes in elevation-any land where 

rainwater naturally channels as it flows downhill. All but the flattest terrain will have 

natural paths of lower elevations where water will follow. The Agencies further state that 

the upper limit of a tributary "is established where the channel begins" which is difficult 

enough for the Corps itself to discern-let alone a typical farmer. In addition, if the "upper 

limit" of a tributary is "where the channel begins," then each farmer or rancher with any 

"channels" on his lands (land with lower elevation in between lands of higher elevations) 

presumably must investigate the entire length of that channel, both up-gradient and 

down-gradient, even beyond his own property lines, to determine whether an OHWM can 

be found. 

Equally obtuse is the Agencies' statement that "a tributary is a longitudinal surface feature 

that results from directional surface water movement and sediment dynamics 

demonstrated by the presence of bed and banks, bottom and lateral boundaries, or other 

indicators of [ordinary high water mark]." (See 79 Fed. Reg. at 22,202.) Even a bed and 

bank have become unnecessary to call water a "tributary"-later in the proposal, the 

Agencies announce that "in some regions of the country where there is a very low 

gradient, the banks of a tributary may be very low or may even disappear at times." This 

example, and countless others, demonstrate the extreme breadth and subjectivity inherent 

in the proposed "tributary" definition. The proposed rule would regulate activities on land 

on which water channels and flows when it rains, so long as the flowing water leaves a 

mark on the land. It may even regulate land where there is no visible channel. If the 

concept of bed, bank and OHWM is retained, under no circumstances should waters that 

do not have all three of these features be considered as tributaries. (p. 7)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. The final rule clearly 

requires the presence of both bed and banks and another indicator of OHWM, if 

one is not present then the water does not qualify as a tributary. Wetlands, lakes, 

ponds, and other features lacking a bed and banks and/or OHWM are no longer 

defined as tributaries in the Final Rule, but may be considered jurisdictional 

“waters of the United States” as adjacent waters or similarly situated waters with a 

significant nexus to (a)(1) through (3) waters. The Connectivity Report supports the 

scientific conclusion that all features that meet this definition of tributary impact the 

physical, chemical, and biological integrity of downstream waters and therefore 

have a significant nexus to (a)(1) through (3) waters. For a further discussion of the 
Clean Water Rule Response to Comments – Topic 8: Tributaries

366

limits of CWA jurisdiction in regards to tributaries and the use of OHWM see the 

summary responses 8.1 and 8.1.2 and the TSD.

8.161 Furthermore, "ordinary high water mark" is a term that encompasses any physical sign of 

water flow, such as changes in the soil, vegetation or debris. When rainwater flows 

through any path on the land, it tends to leave some sort of mark, even if flows are 

infrequent. The definition of OHWM is vague, ambiguous and inconsistently applied. 

Because there are inconsistent interpretations of the OHWM concept, as well as 

inconsistent field indicators and delineation practices, identifying precisely where the 

OHWM ends is simply a matter of judgment. Therefore, reliance on this term provides 

neither certainty nor clarity to the regulated public and unreasonable discretion to the 

regulators.

The Agencies claim the proposal is faithful to key Supreme Court decisions, yet the 

Supreme Court admonished the Agencies' for using the OHWM indicator. The plurality 

opinion in Rapanos v. United States criticized the use of the OHWM as an indicator of 

jurisdiction because it "extended the waters of the United States to virtually any land 

feature over which rainwater or drainage passes and leaves a visible mark-even if only 

the presence of litter and debris." 547 U.S. 715, 725 (2006) (internal quotations omitted). 

Justice Kennedy disparaged the OHWM as providing "no such assurance" of a reliable 

standard for determining a significant nexus. Id. at 780-81 (Kennedy. J., concurring in the 

judgment). If a determination that a particular channel has an OHWM is so broad and 

subjective, how can a farmer know whether a particular low area across his land is simply 

land or instead is a regulated ephemeral tributary? (p. 8)

Agency Response: See responses to the two comments from Alameda County 

Cattlewomen (Doc. #8674) above, TSD sections 1.C, 2D, and 7.A, and summary 

response 8.1.2 above. 

Snell & Wilmer L.L.P. (Doc. #15206)

8.162 ...the Proposed Rule defines "tributaries" as "a water physically characterized by the 

presence of a bed and banks and ordinary high water mark, as defined at 33 CFR 328.3(e 

), which contributes flow, either directly or through another water. .. ." In Arizona, 

however, "water marks" are anything but "ordinary." The Corps of Engineers ' 

publications eve n acknowledge as much. One such publication, the "Distribution of 

Ordinary High Water Mark (OHWM) Indicators and Their Reliability in Identifying the 

Limits of 'Waters of the United States ' in Arid Southwestern channels" (Corp s 2006) 

states :

OHWM indicators, originally intended to define the limits of the OHWM in tidal 

and navigable waters, are confounded by the drastic differences in the climate, 

geology, soil, and vegetation characteristics in which arid streams operate.

Similarly, the "Field Guide to the Identification of the Ordinary High Water Mark 

(OHWM) in the Arid West Region of the Western United States" (Corps 2008) states :

The most problematic ordinary high water (OHW) delineations are associated 

with the commonly occurring ephemeral/intermittent channel forms that dominate 

the Arid West landscape. The climate of the region drastic ally influences the 
Clean Water Rule Response to Comments – Topic 8: Tributaries

367

hydrology, channel-forming processes, and distribution of OHWM indicators 

such that delineations can be inconsistent (over space and time) and problematic.

The Corps acknowledges that OHMW indicators were intended for "tidal and navigable" 

waters, and are not well-suited for the "drastically" different climate in the West. The 

Corps even concludes that use of these delineations in the "Arid West Landscape" is 

"inconsistent" and "problematic." EPA does not have authority to regulate all tributaries 

where there is a clear lack of a "significant nexus" because random and "problematic" 

identification markers may or may not have any relationship to ordinary water flow in 

arid landscapes. (p. 4)

Agency Response: See responses to the two comments from Alameda County 

Cattlewomen (Doc. #8674) above and summary response 8.1.2 above.

Missouri Farm Bureau Federation (Doc. #15224)

8.163 The Agencies’ focus on the presence of a bed, bank and ordinary high water mark 

(OHWM) and any minimal amount of flow that eventually reaches a navigable water 

(directly or through any number of other paths and channels) for identifying tributaries is 

problematic for several reasons. First, the terms “bed” and “bank” simply mean land with 

lower elevation in between lands of higher elevation. Using these terms, any land where 

rainwater naturally channels as it flows downhill could be classified as a tributary—and 

all but the flattest terrain will have natural paths of lower elevations that water will 

follow. Secondly, OHWM encompasses any physical sign of water flow, such as changes 

in the soil, vegetation or debris. Even when flows are infrequent, rainwater tends to leave 

a mark when it moves through any path on land. Use of OHWM as an indicator of 

jurisdiction will result in many ephemeral features being deemed “waters of the U.S.,” 

which was a concern noted in the plurality opinion of the Supreme Court in Rapanos v. 

United States.

400 (p. 2-3)

Agency Response: See responses to the two comments from Alameda County 

Cattlewomen (Doc. #8674) above and summary response 8.1.2 above.

Weyerhaeuser Company (Doc. #15392)

8.164 Countless features on otherwise dry land with no significant nexus to downstream 

navigable-in-fact waters would be deemed jurisdictional under the new definition of 

tributary. The presence of a bed and banks and an ordinary high water mark can be 

established merely by occasional storm events where rainwater channels as it runs from 

higher elevation lands to lower elevation lands. Such events and the resulting indications 

of a “high water mark” are common in forested landscapes, which are almost by 

definition associated with wetter climates. Almost all forest landscapes will have lowlying paths through which water will naturally flow after it rains, leading to endless 

consternation and confusion over whether such paths are jurisdictional “waters.”

 

400 547 U.S. 715, 725 (2006).
Clean Water Rule Response to Comments – Topic 8: Tributaries

368

Moreover, the ordinary high water mark concept, which the Agencies have previously 

acknowledged is vague and confusing,401 is not a reliable basis upon which to distinguish 

between jurisdictional streams and non-jurisdictional erosional features.402 As an example 

of the unreliability, the proposed rule acknowledges that portions of a “tributary” might 

not have a visible ordinary high water mark. Yet, if one can be identified at any point 

upstream, the entire length of the “tributary” is jurisdictional.403 The proposed rule’s 

reliance on the ordinary high water mark as a means to define what features are 

jurisdictional tributaries would not just “extend[] the waters of the United States to 

virtually any land feature over which rainwater or drainage passes and leaves a visible 

mark—even if only the presence of litter and debris.”404 It would also result in the 

extension of CWA jurisdiction to some lands over which rainwater or drainage passes 

without even leaving a mark.

...Moreover, forest owners will face tremendous difficulty determining whether water 

features on their lands fall within the definition of tributary or whether they are nonjurisdictional. For example, given that the ordinary high water mark concept is seemingly 

incapable of consistent application even by agency staff, private forest owners cannot 

reasonably be expected to determine whether channels on their lands are unregulated 

features or whether they are jurisdictional ephemeral tributaries. (p. 4-6)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. The final rule clearly 

requires the presence of both bed and banks and another indicator of OHWM, if 

one is not present then the water does not qualify as a tributary. Wetlands, lakes, 

ponds, and other features lacking a bed and banks and/or OHWM are no longer 

defined as tributaries in the Final Rule, but may be considered jurisdictional 

“waters of the United States” as adjacent waters or similarly situated waters with a 

significant nexus to (a)(1) through (3) waters. The Connectivity Report supports the 

scientific conclusion that all features that meet this definition of tributary impact the 

physical, chemical, and biological integrity of downstream waters and therefore 

have a significant nexus to (a)(1) through (3) waters. For a further discussion of the 

 

401 See GAO, “Waters and Wetlands: Corps of Engineers Needs to Evaluate Its District Office Practices in 

Determining Jurisdiction,” (Feb. 2004).

402 See, e.g., U.S. Army Engineer Research and Development Center, “A Guide to Ordinary High Water Mark 

(OHWM) Delineation for Non-Perennial Streams in the Western Mountains, Valleys, and Coast Region of the 

United States,” ERDC/CRREL TR-14-13, at 4 (Aug. 2014) (“OHWM delineation is not a precise practice. The 

OHWM can take on a variety of appearances and characteristics and may change over time due to natural or 

anthropogenic causes. Best professional judgment and consideration of the unique characteristics of each project site 

are always required.”); U.S. Army Engineer Research and Development Center, “A Review of Land and Stream 

Classifications in Support of Developing a National Ordinary High Water Mark (OHWM) Classification,” 

ERDC/CRREL TR-14-12, at 1 (Aug. 2014) (explaining that spatial and temporal variation in indicators of the 

OHWM poses “challenges to accurate and consistent delineation of the OHWM in rivers and streams throughout the 

U.S.,” and noting that “the spatial and temporal variability of OHWM indicators remains unexplored for most 

stream types in most regions of the U.S.”).

403 See 79 Fed. Reg. at 22,202.

404 Rapanos, 547 U.S. at 725 (plurality); see also id. at 780-81 (Justice Kennedy’s finding that the ordinary high 

water mark concept provides “no such assurance” of a reliable test for determining significant nexus).
Clean Water Rule Response to Comments – Topic 8: Tributaries

369

limits of CWA jurisdiction in regards to tributaries and the use of OHWM see the 

summary responses 8.1 and 8.1.2 above and the TSD.

Utah Farm Bureau Federation (Doc. #16542.1)

8.165 For farmers and ranchers, uncertainty is increased through overly broad or nebulas terms 

in the propose rule including:

...

 using the confusing and SCOTUS-panned concept of ordinary high water mark 

(OHWM) as the key identifier for tributaries,

... (p. 7)

Agency Response: See responses to the two comments from Alameda County 

Cattlewomen (Doc. #8674) above and summary response 8.1.2 above.

8.166 The agencies have proposed an overly broad definition of “tributary” focusing on the 

presence of a bed, bank, ordinary high water mark (OHWM) and any minimum amount 

of flow that eventually reaches directly or through a number of potential pathways to a 

creek or stream that in turn ultimately reaches a traditional navigable water. The agencies 

assert that the upper limit of the tributary “is established where the channel begins.” This 

concept is difficult for the Corps to determine, let alone a typical farmer or rancher.

In Utah, with heavy springtime melting snow packs and occasional torrential summer 

rainstorms the agencies using erosion and OHWM as an indicator of regulatory reach is 

simply outrageous! The “ordinary high water mark” is a term that encompasses any 

physical sign of water flow, such as changes in soil, vegetation or debris. Whenever 

snowmelt or rainwater flows through any path on the land, it leaves a mark – even if the 

flows are infrequent.

It is instructive that the agencies claim the proposed rules are faithful to SCOTUS and its 

decisions – however SCOTUS chastised the agencies for using the OHWM indicator. 

The plurality opinion in Rapanos vs. United States criticized use of the OHWM as an 

indicator of jurisdiction because it “extended the waters of the United States to virtually 

any land feature over which rainwater or drainage passes and leaves a visible mark –

even if only the presence of litter or debris.” 547 U.S 715, 725 (2006)

Even Justice Kennedy in his concurring judgment disparaged the OHWM as providing 

“no such assurance” of a reliable standard for determining a significant nexus. With such 

uncertainty, how can a farmer or rancher know if a particular channel is an unregulated 

erosional feature or a jurisdictional regulated ephemeral tributary? (p. 8)

Agency Response: See responses to the two comments from Alameda County 

Cattlewomen (Doc. #8674) above and summary response 8.1.2 above.

Iowa Farm Bureau Federation (Doc. #15633.1)

8.167 A national OHWM classification system does not currently exist, and according to a 

recent Army Corps of Engineers report, this is needed for nationally consistent and 
Clean Water Rule Response to Comments – Topic 8: Tributaries

370

defensible OHWM delineation practices.405 The report describes that OHWM varies 

spatially and temporally making it difficult to have an accurate and consistent 

determination. It also acknowledges that altered landscapes will present problematic 

circumstances that will not explicitly be included in the OHWM classification.406 As 

most of the landscape in Iowa has been altered by land use activities and climatic 

variables, the minimal explanation in the preamble does not clarify whether a landscape 

feature is a water of the U.S. If it is difficult for Army Corps of Engineers scientists to 

have an accurate and consistent determination of an OHWM, a key factor in whether 

something is a tributary or a gully, how can ordinary citizens be expected to figure this 

out? Currently, whether a landscape feature is a stream is well understood by the public. 

The proposal adds uncertainty and confusion to a previously understood concept of 

“tributary.”

The preamble to the rule undercuts the regulatory definitions by essentially saying the 

Agencies can disregard the regulatory definition requirements when convenient to 

designate a water as jurisdictional. The preamble says, “the upper limit of the tributary is 

established where the channel begins.”407 It also says that “in some regions of the country 

where there is a very low gradient, the banks of a tributary may be very low or even 

disappear at times,” and that “OHWM indicators can be discontinuous within an 

individual tributary due to the variability in hydrologic and climatic influences.”408 The 

rule’s explanation leaves open the ability of the Agencies to ignore the requirements for a 

bed and banks and OHWM, and declare land to be a tributary. With all of this ambiguity 

and case-specific discretion, how is a private property owner to know if his or her land is 

a tributary? (p. 6)

Agency Response: See responses to the two comments from Alameda County 

Cattlewomen (Doc. #8674) above and summary response 8.1.2 above.

Riverport Levee District (Doc. #15655)

8.168 b. The definition proposed for "tributary" creates uncertainty and relies on newly 

released Technical guidance for identifying tributaries.

The proposed definition of "tributary" — which requires only a bed, banks and an 

ordinary high water mark ("OHWM") — will create uncertainty in many instances. While 

a bed, banks and OHWM can be easily identified in some locations, in others those 

features are not evident, especially an OHWM. The proposed rule would nevertheless 

make a tributary a "waters of the U.S." if, at any upstream location, a bed, banks and 

OHWM can be identified. Such a broad definition will potentially require examination of 

miles of upstream tributary features, quite possibly beyond areas that are accessible either 

due to legal or physical constraints. The proposed rule's reliance on being able to define 

and identify an OHWM to determine jurisdiction over tributaries does not provide clarity 

as there has not been established a reliable and repeatable means to identify an OWHM. 

 

405 “A Review of Land and Stream Classifications in Support of Developing a National Ordinary High Water Mark

(OHWM) Classification, U.S. Army Corp of Engineers, ERDC/CREL TR-14-12, August 2014 at 1.

406 Id. at 36.

407 69 Fed. Reg. 22202.

408 Id.
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371

Just shortly after the proposed rule was published in April 2014, the Corps of Engineers 

released new technical guidance (ERDC/CCREL TR-14-13, A Guide to Ordinary High 

Water Mark (OHWM) Delineation for Non-Perennial Streams in the Western Mountains, 

Valleys, and Coast Region of the United States) for delineating the OHWM in nonperennial streams in the Western U.S. The EPA has stated publicly that similar guidance 

is being developed for other regions. The Corps also released in August 2014, 

(ERDC/CCREL TR-14-12, A Review of Land and Stream Classifications in Support of 

Developing a National Ordinary High Water Mark (OHWM) Classification) a report with 

the objective of determining the "most appropriate factors to include in a national 

OHWM classification." As the factors to be used in identifying OHWM's have yet to be 

determined it is blatantly false to claim that the proposed rule provides clarification and 

does not expand jurisdiction. (p. 3)

Agency Response: See response to comment from California Association of 

Winegrape Growers (Doc. #14593) above.

Greene County Farm Bureau (Doc. #17007)

8.169 We are concerned that the new definition of a tributary may be used to justify the 

regulation of features which are not considered a "tributary" in any common sense of the 

word. We understand that the features must have a bed, bank and ordinary high water 

mark. Based upon recent apparent implementation of this definition in Indiana, it appears 

that features which are completely ephemeral and drain few acres are going to be 

considered tributaries. Those features provide no base flow and thus would not normally 

be considered a tributary as it is commonly understood or as it would appear to have been 

historically interpreted by the agencies. (p. 2)

Agency Response: See responses to the two comments from Alameda County 

Cattlewomen (Doc. #8674) above and summary response 8.1.2 above.

Agribusiness Association of Kentucky et al. (Doc. #18005)

8.170 The Agencies have proposed an overly broad "tributary" definition focusing on the 

presence of a bed, bank, ordinary high water mark (OHWM) and any minimal amount of 

flow that eventually reaches (directly or through any number of other paths and channels) 

to a creek or stream that in turn ultimately flows to a traditional navigable water. See 79 

Fed. Reg. at 22,263.409 The terms "bed" and "bank" simply mean land with lower 

elevation in between lands of higher elevation. This includes land with only subtle 

changes in elevation—any land where rainwater naturally channels as it flows downhill. 

All but the flattest terrain will have natural paths of lower elevations that water will 

follow. The Agencies further state that the upper limit of a tributary "is established where 

the channel begins" which is difficult enough for the Corps itself to discern— let alone a 

typical farmer or rancher.410 Id. at 22,202. In addition, if the "upper limit" of a tributary is

 

409 The rule would provide: "The term tributary means a water physically characterized by the presence of a bed and 

banks and ordinary high water mark, as defined at 33 CFR § 328.3(e), which contributes flow, either directly or 

through another water, to a water identified in paragraphs (a)(1) through (4) of this section."

410 Presentation by Matthew K. Mersel, USACE, "Development of National OHWM Delineation Technical 

Guidance," March 4, 2014. Attached hereto as Appendix F.
Clean Water Rule Response to Comments – Topic 8: Tributaries

372

"where the channel begins," then each farmer or rancher with any "channels" on his lands 

(land with lower elevation in between lands of higher elevations) presumably must 

investigate the entire length of that channel, both up-gradient and down-gradient, even 

beyond his own property lines, to determine whether an OHWM can be found. 

Equally obtuse is the Agencies' statement that "a tributary is a longitudinal surface feature 

that results from directional surface water movement and sediment dynamics 

demonstrated by the presence of bed and banks, bottom and lateral boundaries, or other 

indicators of [ordinary high water mark]." Id. at 22,202. Even a bed and bank have 

become unnecessary to call water a "tributary"—later in the proposal, the Agencies 

announce that "in some regions of the country where there is a very low gradient, the 

banks of a tributary may be very low or may even disappear at times." Id. This example, 

and countless others, demonstrate the extreme breadth and subjectivity inherent in the 

proposed "tributary" definition. The proposed rule would regulate activities on land on 

which water channels and flows when it rains, so long as the flowing water leaves a mark 

on the land. It may even regulate land where there is no visible channel. 

...

Furthermore, "ordinary high water mark" is a term that encompasses any physical sign of 

water flow, such as changes in the soil, vegetation or debris. When rainwater flows 

through any path on the land, it tends to leave some sort of mark, even if flows are 

infrequent. The Agencies themselves recognize that the definition of OHWM is vague, 

ambiguous and inconsistently applied.411 In fact, an official from the Corps' Philadelphia 

District has observed that, due to inconsistent interpretations of the OHWM concept, as 

well as inconsistent field indicators and delineation practices, identifying precisely where 

the OHWM ends is simply a matter of judgment,412 so reliance on this term provides 

neither certainty nor clarity. Moreover, we understand that the Corps is in the process of 

redefining how it determines an OHWM, yet nowhere in the proposal do the Agencies 

signal to the public that this behind-the-scenes change is occurring, placing a key term in 

the proposed rule beyond public comment.413 (p. 6-8)

Agency Response: See responses to the two comments from Alameda County 

Cattlewomen (Doc. #8674) above and summary response 8.1.2 above.

Wilkin County Farm Bureau (Doc. #19489)

8.171 Wilkin County Farm Bureau has significant concerns with the limitless jurisdiction the 

proposed rule provides the agencies. 

 

411 GAO Report, "Waters and Wetlands: Corps of Engineers Needs to Evaluate Its District Office Practices in 

Determining Jurisdiction," February 2004.

412 Presentation by Matthew K. Mersel, USACE, "Development of National OHWM Delineation Technical 

Guidance," March 4, 2014. See Appendix F.

413 Wetlands Regulatory Assistance Program (WRAP), "A Review of Land and Stream Classifications in Support of 

Developing a National Ordinary High Water Mark (OHWM) Classification" by, Matthew K. Mersel, Lindsey E. 

Lefebvre, and Robert W. Lichvar (August 2014), 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254/Article/486085/ordinary-highwater-mark-ohwm-research-development-and-training.aspx. Attached at Appendix G.
Clean Water Rule Response to Comments – Topic 8: Tributaries

373

...

 In addition, the rule uses the unclear concept of ordinary high water mark, as well 

as bed and bank, as the key identifiers for tributaries. This would include land 

with only subtle changes in elevation, where any land where rainwater naturally 

channels as it flows downhill. 

... (p. 2)

Agency Response: See responses to the two comments from Alameda County 

Cattlewomen (Doc. #8674) above and summary response 8.1.2 above.

American Water Company (Doc. #6935.1)

8.172 The definition proposed for "tributary" is overbroad and would create uncertainty for 

water distribution systems.

American Water Company, like most water companies, has a distribution system which 

crosses under or, less frequently, above tributaries. We estimate that hundreds of 

thousands of such crossings are currently in place, nationwide. Urban development 

requires the placement of new water mains to meet customer needs and the relocation of 

existing mains for many reasons, such as urban redevelopment or for roadway 

modifications. The proposed definition of "tributary" - which requires only a bed, banks 

and an ordinary high water mark ("OHWM") - will create uncertainty in many instances 

for water companies. More specifically, although these required features - a bed, banks 

and OHWM - can be identified in some locations, those features are often not present in 

locations proposed for a water main. The proposed rule would nevertheless make a 

tributary a WOTUS if, at any upstream location, a bed, banks and OHWM could be 

identified. Adopting such an overly broad definition would require water companies to 

examine miles of upstream tributary features, quite possibly outside the footprint of their 

distribution system or even the county in which they operate, in order to guess whether an 

otherwise dry creek with no apparent bed and/or/bank and/or OHWM at the crossing 

location might be a jurisdictional WOTUS.

To eliminate this uncertainty, American Water Company proposes that the Agencies 

exempt portions of tributaries from permitting where the area to be crossed by a water 

main does not exhibit the features of a bed, a bank and an OHWM. (p. 1-2)

Agency Response: See responses to the two comments from Alameda County 

Cattlewomen (Doc. #8674) above and summary response 8.1.2 above.

Northwest Colorado Council of Governments Water Quality/Quantity Committee (Doc. #10187)

8.173 Some waters may qualify as a tributary under the proposed rule because they have banks, 

a bed, and an ordinary high water mark. However, the same drainage systems may exist 

wholly in uplands, drain only uplands, and contribute a minimal amount of flow only 

during significant rain events. Under the proposed rule, it appears that a natural drainage 

system with a bed, bank, and ordinary high water mark would be automatically 

jurisdictional even if it may exist wholly in uplands, drain only uplands, and contribute a 

minimal amount of flow only during significant rain events. With such waters, a 
Clean Water Rule Response to Comments – Topic 8: Tributaries

374

significant nexus may not exist with traditionally navigable water. The rule should clarify 

how the agencies would treat such natural drainage systems. (p. 4)

Agency Response: See response to comment from California Association of 

Winegrape Growers (Doc. #14593) above

Duke Energy (Doc. #13029)

8.174 ... uncertainty is created by:

... using the confusing concept of ordinary high water mark (OHWM) as the key 

identifier for tributaries;... (p. 10)

Agency Response: The final rule continues the longstanding practice of using the 

OHWM to determine the lateral extent of jurisdiction for tributaries. The final rule 

does not change the definition or alter the methods for identification of OHWM. 

The OHWM continues to be identified using indicators of regular high flows whose 

return interval varies across the country based on climate, hydrology, and other 

factors. The Corps and EPA plan to continue to build on the more than a decade of 

effort spent improving the consistency and rigor of OHWM identifications, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates.

8.175 One of the fundamental aspects of this definition relies on how you determine an 

OHWM, which is regionally variable.

The definition of OHWM currently in use by the Corps is “that line on the shore 

established by the fluctuations of water and indicated by physical characteristics such as 

clear, natural line impressed on the bank, shelving, changes in the character of soil, 

destruction of terrestrial vegetation, the presence of litter and debris, or other appropriate 

means that consider the characteristics of the surrounding areas.”414 However, 

inconsistent interpretations of the OHWM concept have led to inconsistent field 

indicators and delineation practices among the different Corps districts.

This definition is problematic because many of the OHWM physical indicators can occur 

wherever water is flowing over land, regardless of frequency or duration. With this 

OHWM definition in use, it becomes difficult to distinguish between small streams or 

drainages and erosional features such as gullies. In most cases, erosional features would 

not exhibit an OHWM. However, this is a subjective interpretation left to the “best 

professional judgment” of the individual making the determination.

The Corps indicated in April 2014 that they were planning to issue guidance, with 

technical support from EPA, to redefine the OHWM metrics and standardize the 

concept’s implementation with the intent to identify “a more uniform approach to 

assessing ordinary high water mark (OHWM).”415 And just recently, in August 2014, the 

Corps released a report that reviews existing land and stream classifications and assesses 

 

414 33 CFR § 328.3(e)

415 Bridget DiCosmo, InsideEPA.com, Agencies’ Workgroup Eyes Changes to Key Delineation Guides (Apr. 30, 

2014). (See Appendix C)
Clean Water Rule Response to Comments – Topic 8: Tributaries

375

the benefits and limitations of each approach for the purpose of developing a national 

OHWM classification. It also presents a preliminary version of a national OHWM 

classification.416 While it is admirable that the agencies are trying to achieve 

standardization for implementing this metric across the various Corps Districts, it is 

greatly concerning that this is being conducted outside of this rulemaking, offering no 

opportunity for public input. (p. 24-25)

Agency Response: See responses to the two comments from Alameda County 

Cattlewomen (Doc. #8674) above and summary response 8.1.2 above. 

Murray Energy Corporation (Doc. #13954)

8.176 ...the Agencies’ new definition of “tributary” is clearly at odds with a fair and accurate 

reading of Rapanos... To compound this error, the Agencies jettison even the barest and 

minimal requirements of OHWM and bed and bank, well-established features of the 

historical definition of tributaries under the CWA, by proposing to expand the definition 

of tributaries to water features, such as wetlands, that lack bed and bank and OWHM... 

(p. 10)

Agency Response: See responses to the two comments from Alameda County 

Cattlewomen (Doc. #8674) above and summary response 8.1.2 above.

8.177 The use of OHWM as the primary physical indicator in determining the lateral limits of 

jurisdiction has been the Corps’ practice for many years.417 To abandon its use and 

redefine a jurisdictional tributary as any feature that “drains” to a traditional navigable 

water, regardless of the volume of flow or presence of an OHWM, creates even greater 

confusion and uncertainty regarding the lateral limits of a tributary. (p. 11)

Agency Response: The final rule has retained the requirement for OHWM for 

tributaries as the commenter recommends. For further discussion see responses to 

the two comments from Alameda County Cattlewomen (Doc. #8674) above and 

summary response 8.1.2 above.

Department of Public Works, City of Northglenn, Colorado (Doc. #14990)

8.178 3. Ordinary High Water Mark. The Proposed Rule retains uncertainty regarding the 

identification of an Ordinary High Water Mark (OHWM) on features that have been 

fortified to prevent erosion. For example, certain stormwater ditches may not have a 

natural OHWM but have been armored with angular cobble to prevent headcutting. 

Based on conversations with EPA and USACE staff, the OHWM along fortified channels 

should be identified using water stains on the channel fortification. This guidance 

presents a dilemma to MS4 permittees when determining whether or not to fortify upland 

 

416 A Review of Land and Stream Classifications in Support of Developing a National Ordinary High Water Mark 

(OHWM) Classification, August 2014 (ERDC/CRREL TR-14-12)

417 See Corps RGL 05-05, Ordinary High Water Mark Identification, located at

http://www.usace.army.mil/Portals/2/docs/civilworks/regulatory/cwa_guide/app_h_rgl05-05.pdf; See also GAO-04-

297 Report, Waters and Wetlands, Corps of Engineers Needs to Evaluate Its District Office Practices in Determining

Jurisdiction, located at http://www.gao.gov/assets/250/241520.pdf.
Clean Water Rule Response to Comments – Topic 8: Tributaries

376

vegetated swales: they can either leave the swale unprotected (but retain its non-WOTUS 

status; or they can fortify the swale but increase the potential that it will be WOTUS.

The City of Northglenn requests that the Proposed Rule clarify how OHWM should be 

identified in these situations. Further, we request that the Agencies evaluate the 

advisability of imposing regulatory burden at locations that have been protected from 

future erosion and sediment transport events. (p. 2-3)

Agency Response: As discussed above in the summary response for this 

compendium, the final rule does not change the definition or indicators of Ordinary 

High Water Mark (OHWM). The final rule does provide additional clarity that all 

tributaries must contain both a bed and banks and an OHWM. Fortification of an 

upland flowpath may create bed and banks however the other OHWM indicators 

require the presence of flow.

Arizona Public Service Company (Doc. #15162)

8.179 ...SAB advises reconsideration of the definition of tributaries since, in its opinion, not all 

tributaries have ordinary high water marks, and there are other features that are 

questionable for this proposed definition.418 SAB recommends replacing “ordinary high 

water marks” in the tributaries definition with “and other evidence of flow.”419 The 

Agencies have noted that the goal of this proposed rule is to clarify the WOTUS 

definition to provide consistency and program predictability420; however, even their own 

technical advisor panel has brought forth comments that must be evaluated and presented 

to the regulated community and general public for review and consideration. The addition 

of “and other evidence of flow” simply adds yet another term which, if used by the 

Agencies, would require a definition with an opportunity to review and comment on such 

definition. Thus, APS strongly recommends the Agencies consider withdrawing this 

proposed rule so a meaningful discussion with all interested parties can occur. Such 

communication will aide in a more widely-accepted proposed rule to clarify the WOTUS 

definition. The additional time needed to conduct this additional outreach and to repropose the WOTUS definition could very likely be less than that needed to litigate a 

final rule that defines WOTUS far too broadly. (p. 10)

Agency Response: See responses to the two comments from Alameda County 

Cattlewomen (Doc. #8674) above and summary response 8.1.2 above.

Louisville and Jefferson County Metropolitan Sewer District (Doc. #15413)

8.180 Ordinary High Water Mark (OHWM): Although the definition is clear for naturalized 

streams, it is less clear for OHWM's found on concrete conveyances that may be 

considered jurisdictional. Staining is the primarily indicator to determine the OHWM in 

concrete channels, however , in a municipal system there may be concrete conveyances 

that flow a few times a year, carrying only sheetflow, which do not leaving stain lines. 

 

418 SAB Consideration of the Adequacy of the Scientific and Technical Basis of the EPA’s Proposed Rule titled

“Definition of Waters of the United States under the Clean Water Act” (Sept. 30, 2014).

419 Id.

420 79 Fed. Reg. at 22188.
Clean Water Rule Response to Comments – Topic 8: Tributaries

377

Accordingly, MSD requests that the definition of OHWM be revised and clarified as it 

relates to concrete conveyances. (p. 2)

Agency Response: See response to comment from American Society of Civil 

Engineers (Doc. #19572) and summary response 8.1.2 above.

West Bay Sanitary District, Novato Sanitary District, West County Wastewater District, Union 

Sanitary District and West Valley Sanitation District, California (Doc. #16610)

8.181 ... the SAB has suggested that the definition of "tributary" should be expanded to include 

those areas with "bed, bank and other evidence of flow." (SAB Draft Report (09/17/14) at 

pg. 2, lines 37-38.) This suggested expansion is more inclusive than the currently 

proposed language about requiring an ordinary high water mark, and could be argued to 

extend to every street, every gutter, and every swale or storm drain channel draining 

neighborhoods in the country would potentially fall under this expanded criterion, which 

is well beyond the realm of reasonableness. (p. 8)

Agency Response: See responses to the two comments from Alameda County 

Cattlewomen (Doc. #8674) above and summary response 8.1.2 above.

Southern Company (Doc. #14134)

8.182 I. The New Definition of “Tributary” Extends to Waters that Historically Have Not 

Been Regulated and that Have, at Best, an Insubstantial Connection with TNWs

The agencies propose a new definition for “tributary” that is extremely broad. It would 

make all tributaries of TNWs jurisdictional, without regard to a “significant nexus” 

evaluation. This would include all perennial, intermittent, and ephemeral features. That 

is, under the proposal as written, all tributaries would be deemed by rule to have a 

significant nexus to TNWs. In several respects, this aspect of the proposal far exceeds the 

scope of tributaries historically deemed jurisdictional and is not supported by science or 

law. 

...

D. The Agencies Should Not Categorically Include Features Without a Bed, Bank and 

OHWM in the Definition of “Tributary”

In so far as the proposal treats wetlands and other “waters” that do not contain clear and 

discernible features such as bed and bank and OHWM as categorically jurisdictional, the 

agencies’ proposed approach to defining “tributaries” is inconsistent with their own 

stated goal of providing consistency, clarity, and certainty. The definition is also at odds 

with the agencies’ description of a tributary elsewhere in the proposal, where the agencies 

seem to acknowledge the necessary presence of bed and bank and OHWM. 79 Fed. Reg. 

at 22202 (“A tributary is a longitudinal surface feature that results from directional 

surface water movement and sediment dynamics demonstrated by the presence of bed 

and banks, bottom and lateral boundaries, or other indicators of OHWM.”). SAB 

panelists also criticized the confusion created by agencies’ treatment of tributaries.

The use of OHWM as the primary physical indicator in determining the lateral limits of 

jurisdiction has been the Corps’ practice for many years. To abandon its use and redefine 

a jurisdictional tributary as any feature that “drains” to a TNW, regardless of the volume 
Clean Water Rule Response to Comments – Topic 8: Tributaries

378

of flow or presence of an OHWM, creates unacceptable confusion and uncertainty 

regarding the lateral limits of a tributary. Moreover, wetlands and other water bodies 

lacking an OHWM should not be analyzed under the tributary framework. SAB Panel 

Memo at 29 (“I recommend that wetlands be removed from the definition of tributaries . . 

. basing their jurisdiction on adjacency is more clear, and removes ambiguity . . .”) (Dr. 

Fennessy Comments).

For these reasons, Southern Company would support elements of the agencies’ suggested 

alternative to their definition of “tributary” where (1) wetlands that connect tributary 

segments would be deemed to be “adjacent” wetlands; (2) tributary would, among other 

things, be limited to features having a bed and bank and OHWM, consistent with 

historical practice, and the upper limit of the tributary would be defined by the point 

where these features cease to be identifiable; and (3) wetlands would not be considered 

tributaries, and would be assessed based on adjacency principles to determine whether 

they are jurisdictional. We do not support all aspects of this alternative approach (e.g., it 

would retain the man-made or natural breaks provisions), but if greater clarity and 

consistency—rather than expansion of jurisdiction—is an important goal, then it presents 

a far more appropriate alternative over the agencies proposed approach to treatment of 

wetlands and other waters in the context of defining “tributary.” (p. 30, 34-35)

Agency Response: The final rule reflects the recommendations made in the above 

comment regarding wetlands and other waters being called tributaries. Wetlands 

and other features without an OHWM and bed and bank are evaluated as adjacent 

waters under the final rule. 

The final rule clearly requires the presence of both bed and banks and another 

indicator of OHWM, if one is not present then the water does not qualify as a 

tributary. The agencies have concluded that flow of a sufficient volume, frequency, 

and duration create and maintain the physical characteristics of tributaries, such as 

bed and banks and another indicator of OHWM. The Connectivity Report supports 

the scientific conclusion that all features that meet this definition of tributary impact 

the physical, chemical, and biological integrity of downstream waters and therefore 

have a significant nexus to (a)(1) through (3) waters. For a further discussion of the 

limits of CWA jurisdiction in regards to tributaries and the use of OHWM see 

summary response 8.1 and 8.1.2 and the TSD.

Metropolitan Water District of Southern California (Doc. #14637)

8.183 b. The Agencies should consider regional conditions when establishing mitigation 

requirements

The term "ordinary high water mark" is defined in the rule to mean that line on the shore 

established by the fluctuations of water and indicated by physical characteristics such as a 

clear, natural line impressed on the bank, shelving, changes in the character of soil, 

destruction of terrestrial vegetation, the presence of litter and debris, or other appropriate 

means that consider the characteristics of the surrounding areas. In practice, this 

definition does not address the implications for jurisdictional scope inherent in the 

methodology for a tributary. OHWM will continue to be used in identification of the 

OHWM in the arid southwest.
Clean Water Rule Response to Comments – Topic 8: Tributaries

379

Currently, in the arid west, the methodology used to locate and to identify the OHWM is 

described in A Field Guide to the Identification of the Ordinary High Water Mark 

(OHWM) in the Arid West Region of the Western United States: A Delineation Manual

ERDC/CRREL TR-08-12 (2008) (2008 Lichvar Field Manual) issued by the Corps. (It 

should be noted that the methodology in the 2008 Lichvar Field Manual differs from the 

methodology prescribed in the 2005 Regulatory Guidance Letter 0505.) Within this 

geographic region the following water bodies are located: dry arroyos and washes that 

flow only after infrequent storm events, isolated ponds, and intermittent and ephemeral 

streams with an indeterminate connection to jurisdictional tributaries under the Final 

Rule, and determine their lateral extent. However, a tributary, by definition, must also 

contribute flow to a downstream navigable waters. Due to the intermittent and seasonal 

nature of flows through drainages in the arid west, the active floodplain zone can 

correspond to the ten-year floodplain or higher. Depending on the topography, locating 

the OHWM at the edge of the ten-year floodplain rather than at the location of the 

bankfull channel can add significant acreage to jurisdictional delineations as it increases 

the scope of jurisdiction laterally away from the incised channel of the drainage.

This approach is different from and more expansive than that used in other regions of the 

U.S. In other words, the size and reach of jurisdiction around tributaries in the arid west 

will be much broader than in other areas of the U.S. using the methodology in the 2008 

Lichvar Field Manual. This discrepancy will result in increased mitigation for impacts to 

waters of the U.S. in the arid west as compared to other regions of the U.S. For this 

reason, Metropolitan requests that the Agencies rectify the bias toward increased 

mitigation in the arid west arising from this methodological discrepancy in the proposed 

rule. For instance, the Agencies could issue guidance that the bankfull channel should be 

used as the feature for determining acreage of jurisdiction. Furthermore, Metropolitan 

requests that all guidance and field manuals related to determining jurisdiction in practice 

be distributed for public review and comment prior to their use and before the proposed 

rule is finalized. (p. 8-9)

Agency Response: The final rule continues the longstanding practice of using the 

OHWM to determine the lateral extent of jurisdiction for tributaries. The OHWM 

continues to be identified using indicators of regular high flows whose return 

interval varies across the country based on climate, hydrology, and other factors. 

The agencies plan to continue to build on the more than a decade of effort spent 

improving the consistency and rigor of OHWM identifications, especially in the 

western US where two guidebooks for OHWM identification have already been 

developed, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates. The methodology found in the arid west manual 

mentioned in the comment applies the indicators discussed in RGL 05 – 05 to the 

hydrologic and climatic circumstances found in the arid southwest. The Arid West 

OHWM manual was developed to address the identified challenges in low-gradient, 

alluvial ephemeral/intermittent channel forms, by using other features associated 

with the limits of the active floodplain (channel), which are easily identified in the 

field, less variable over time, and statistically linked to the hydrologic and hydraulic 

parameters of ephemeral and intermittent arid channel forms, to support the 
Clean Water Rule Response to Comments – Topic 8: Tributaries

380

traditional OHWM indicators. This method uses stream geomorphology and 

vegetation response to the dominant stream discharge and represents the most 

consistent and repeating pattern associated with “ordinary” events representing 

OHW. Mitigation requirements are outside the scope of this rulemaking. 

Nucor Corp. (Doc. #14963)

8.184 The Proposed Rule Fails to Appropriately Define Ordinary High Water Mark The 

proposed rule establishes a definition for jurisdictional tributaries which provides that a 

tributary "means a water physically characterized by the presence of a bed and banks and 

ordinary high water mark, as defined at 33 CFR 328.3(e) ... " 79 Fed. Reg. 22263. One of 

the chief elements of being characterized as a tributary is whether a waterbody has an 

ordinary high water mark (OHWM). The definition of the term is so vague and 

ambiguous that it has historically been problematic and lead to inconsistent interpretation 

and application, resulting in inconsistent delineation practices. Recognizing this flaw, the 

Army Corps of Engineers resorted to issuing guidance on the identification of the 

OHWM in 2005. U.S. Army Corps of Engineers, Regulatory Guidance Letter No. 05-05 

(December 7, 2005). Like the definition, this guidance is so ambiguous that the Agencies 

appear to be developing a new OHWM standard. See, e.g., U.S. Army Engineers 

Research and Development Center, A Guide to Ordinary High Water Mark (OHWM) 

Delineation for Non-Perennial Streams in the Western Mountains, Valley and Coast 

Region of the United States (August, 2014); U.S. Army Engineers Research and 

Development Center, A Review of Land and Stream Classifications in Support of 

Developing a National Ordinary High Water Mark (OHWM) Classification (August, 

2014). Because the definition of "tributary" hinges on the definition of OHWM, any 

changes impacting that definition will impact the definition of "tributary" and must, 

under the Administrative Procedure Act (APA), be made in this rulemaking, and not in 

guidance. (p. 11-12)

Agency Response: The final rule continues the longstanding practice of using the 

OHWM to determine the lateral extent of jurisdiction for tributaries. The final rule 

does not change the definition or alter the methods for identification of OHWM. 

The OHWM continues to be identified using indicators of regular high flows whose 

return interval varies across the country based on climate, hydrology, and other 

factors. The Corps and EPA plan to continue to build on the more than a decade of 

effort spent improving the consistency and rigor of OHWM identifications, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates. The documents identified in the comment were developed 

to help the public and field staff understand location site conditions and consistently 

identify the OHWM. The agencies have concluded that flow of a sufficient volume, 

frequency, and duration create and maintain the physical characteristics of 

tributaries, such as bed and banks and another indicator of OHWM. The 

Connectivity Report supports the scientific conclusion that all features that meet 

this definition of tributary impact the physical, chemical, and biological integrity of 

downstream waters and therefore have a significant nexus to (a)(1) through (3) 

waters.
Clean Water Rule Response to Comments – Topic 8: Tributaries

381

Pennsylvania Independent Oil and Gas Association (Doc. #15167) 

8.185 How will an OHWM be determined? Delineation of OHWM is open to subjective 

interpretation. The identification of the OHWM limits will be influenced by 

uncharacteristically high rainfall events and are seasonably difficult to identify. (p. 17)

Agency Response: See response to comment from Nucor Corp. (Doc. #14963 and 

summary response 8.1.2 above. 

Lower Colorado River Authority (Doc. #16332)

8.186 The terms used by the Agencies to define “tributaries” should be clarified. The terms 

“bed” and “bank” can include any land at lower elevation that lies between lands at 

higher elevation. All but the flattest terrain will feature some natural areas of lower 

elevations that water will follow. The term “OHWM” is similarly broad, and can 

encompasses any physical sign of water flow, such as changes in the soil, vegetation, or 

debris. The Agencies themselves have admitted that their definition of OHWM is vague, 

ambiguous, and inconsistently applied.421 The Agencies should revise the rule to clarify 

how field staff will determine the presence of a bed, bank, and OHWM. The Agencies 

should also revise the rule to clarify how they intend to treat and define “breaks” in the 

OHWM. (p. 15) 

Agency Response: See responses to the two comments from Alameda County 

Cattlewomen (Doc. #8674) above and summary response 8.1.2 above. 

Tri-State Generation and Transmission Association, Inc. (Doc. #16392)

8.187 Several comments of the SAB (Dr. Pausch; Dr. Aldous; Dr. Sullivan) also indicate that 

the concept of the ordinary high water mark (OHWM) should not be a required attribute 

of a tributary. The SAB panel recommends an alternative definition as presence of "bed, 

bank and other evidence of flow".422 In particular the "other evidence of flow" language 

would substantially expand what is currently encompassed by the OHWM to delineate 

tributary boundaries. For example, "other evidence of flow" could occur at locations 

distant from the active channel and in floodplains which are better regulated by the 

Federal Emergency Management Agency and local floodplain administrators. Similarly 

"other evidence of flow" could be broadened to include sheet flow and erosion which, as 

the Agencies propose, should not fall within the definition of WOTUS.

 

421 U.S. General Accounting Office, Waters and Wetlands: Corps of Engineers Needs to Evaluate Its District Office

Practices in Determining Jurisdiction (Feb. 2004), available at http://www.gao.gov/new.items/d04297.pdf. See

also, Potential Impacts of Proposed Changes to the Clean Water Act Jurisdiction Rule: Testimony Before the House

Transportation and Infrastructure Committee Subcommittee on Water Resources and Environment 3 (June 11,

2014), available at http://www.fb.org/newsroom/nr/nr2014/06-11-14/WOTUS_testimony_6-11-14.pdf (statement of

Bob Stallman, President, American Farm Bureau Federation) [hereinafter, Farm Bureau Testimony] (“the [Army]

Corps’ Philadelphia District has observed that, due to inconsistent interpretations of the OHWM concept, as well as

inconsistent field indicators and delineation practices, identifying precisely where the OHWM ends is nothing more

than a judgment call.”).

422 Comments to the chartered SAB on the Adequacy of the Scientific and Technical Basis of the Proposed Rule 

Titled "Definition of 'Waters of the United States' Under the Clean Water Act". at page 2.
Clean Water Rule Response to Comments – Topic 8: Tributaries

382

The current definition of the OHWM already includes the phrase "or other appropriate 

means that consider the characteristics of the surrounding areas" which allows for other 

factors to be considered. Therefore, Tri-State does not agree with the SAB panelists that 

the OHWM concept should be removed from the definition of tributaries or expanded to 

include "other evidence of flow". Though problematic in arid regions, the OHWM 

concept is a long-standing definition used to establish the lateral limits of CWA 

jurisdiction absent the presence of adjacent wetlands. Tri-State recommends the Agencies 

consider further improvements to the ordinary high water mark either (a)(1) through 

additional field guidance, such as the recently issued guidance, or through a separate 

future rulemaking process. In many ways the existing problems with decisions on CWA 

jurisdiction for tributaries lies in the difficulties and subjectivity of the OHWM concept, 

rather than the proposal to regulate all tributaries by rule. Since the OHWM determines 

the presence and limits of a tributary, it is a problem area that deserves further 

consideration than it is being given under the proposed rule. (p. 13)(a)(3) water to be 

considered per se jurisdictional. 

Agency Response: The final rule retains the requirement for bed and banks and 

another indicator of OHWM for tributaries as suggested in the comment above. The 

Corps and EPA plan to continue to build on the more than a decade of effort spent 

improving the consistency and rigor of OHWM identifications, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates.

Northern California Association (Doc. #17444)

8.188 ...the SAB recently advised the EPA to reconsider the definition of tributaries in the 

proposed rule because the SAB maintains that not all tributaries may have ordinary high 

water marks. The SAB stated that "an ordinary high water mark may be absent in 

ephemeral streams within arid and semi-arid environments or in low gradient landscapes 

where the flow of water is unlikely to cause an ordinary high water mark.,, 423 The SAB 

advised the agency to "consider changing the wording in the definition to 'bed, bank, and 

other evidence of flow' .”424 We believe this would further broaden the jurisdiction of the 

CWA beyond what Congress intended, as any indication of surface water runoff from an 

isolated rain event in a field, dirt road or parking lot could meet this new expanded 

definition, becoming a "water of the U.S." subject to CWA regulation. (p. 6)

Agency Response: The final rule retains the requirement for bed and banks and 

another indicator of OHWM for tributaries as suggested in the comment above.

Ducks Unlimited (Doc. #11014)

8.189 ...related to the definition of tributaries, we agree with the recommendation contained in 

the EPA's Science Advisory Board's (SAB) letter to the Administrator (9/30/14) 

 

423 [EPA-SAB-14-007] Science Advisory Board letter to EPA Administrator Gina McCarthy dated September 30,

2014 reo Science Advisory Board (SAB) Consideration of the Adequacy of the Scientific and Technical Basis of the

EPA's Proposed Rule titled "Definition of Waters of the United States under the Clean Water Act."

424 Ibid.
Clean Water Rule Response to Comments – Topic 8: Tributaries

383

regarding the adequacy of the scientific and technical basis for the proposed rule as it 

relates to the definition of tributaries. The SAB's draft report "advises the EPA to 

reconsider the definition of tributaries because not all tributaries have ordinary high water 

marks [OHWM]," and that "an OHWM may be absent in ephemeral streams within arid 

and semi-arid environments or low gradient landscapes where the flow of water is 

unlikely to cause an OHWM." Noting the difficulty that has been experienced in some 

areas with application of the OHWM criterion, we agree with the SAB's recommendation 

that the wording of the definition of tributary be changed to "bed, bank, and other 

evidence of flow." In other respects, we generally support the definition of tributaries and 

find it to be in keeping with the related science. (p. 13-14)

Agency Response: The final rule requires the presence of both bed and banks and 

another indicator of OHWM, if one is not present then the water does not qualify as 

a tributary. The agencies continue to address regional concerns about the 

identification of the OHWM through the development of regional manuals that 

apply the indicators discussed in the regulation and RGL 05-05 to the regional 

hydrologic and climatic circumstances. 

8.190 We summarize our primary conclusions and recommendations below, and provide the 

page numbers for other, related findings and recommendations, and a more complete 

articulation of the rationale and technical information in support of our comments.

 ...we also agree with the Science Advisory Board's recommendation regarding 

reconsideration of the use of the "ordinary high water mark" as a part of the 

definition of "tributary" ... (p. 75)

Agency Response: See response to the prior comment from Ducks Unlimited 

(Doc. #11014) above and TSD sections 2.A and 7.A. 

Southern Environmental Law Center et al. (Doc. #13610)

8.191 Agency Comment Request: The agencies’ request comment on . . . the definition of 

tributaries and provide a clear explanation of their lateral and upstream extent.

Comment: It is confusing to define tributaries as including an ordinary high water mark 

and then almost immediately carve out exceptions to that rule for wetlands and other 

waters that may lack an ordinary high water mark. We suggest the following definition 

instead:

For the purposes of the rule, the term “tributary” means:

1) a water (such as a stream, creek, or river) that has a bed and bank and 

ordinary high water mark and that contributes flow to other jurisdictional 

waters either directly or through another water or a discrete conveyance; 

or

2) a nonlinear water (such as a wetland, lake, or pond) even if it does not 

possess a bed or bank or ordinary high water mark as long as it contributes 

flow to other jurisdictional waters either directly or through another water 

or a discrete conveyance. (p. 13)
Clean Water Rule Response to Comments – Topic 8: Tributaries

384

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. As described in the 

summary responses 8.1 and 8.1.2, the final rule clearly requires the presence of both 

bed and banks and another indicator of OHWM, if one is not present then the water 

does not qualify as a tributary. Wetlands, lakes, ponds, and other features lacking a 

bed and banks and/or OHWM are no longer defined as tributaries in the Final Rule, 

but may be considered jurisdictional “waters of the United States” as adjacent 

waters or similarly situated waters with a significant nexus to (a)(1) through (3) 

waters. 

8.192 The ordinary high water mark (OHWM) has long been a measure to define a stream, 

indicating volume and flow. OHWM demonstrates a continuous channel providing a 

clear linkage between a tributary and downstream waters in many places. However, the 

traditional approach to measuring OHWM has relied on physical characteristics alone, 

neglecting hydrologic measures.425 In the arid Southwest, for instance, typical OHWM 

indicators have not been found to be a reliable determination of a stream given the vast 

difference in “ordinary” flood patterns, and as a result it is suggested that the floodplain 

itself be used as the OHWM.426 EPA already recommends a suite of factors to determine 

headwater streams, which may be described as “dynamic zones within stream 

networks.”427 While a traditional OHWM is certainly a positive indicator of a tributary, it 

is not a prerequisite. Moreover, because small headwater streams are the most susceptible 

to changes in size,428 the OHWM is more variable and more difficult to ascertain. Thus, 

we recommend that the proposed rule make clear that tributaries can be defined by the 

presence of an OHWM or more broadly by hydrologic, geomorphic, ecological and 

physical factors to ensure that tributaries across a range of regional and climatic 

variations are protected. (p. 47-48)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. As described in the 

summary response responses 8.1 and 8.1.2, the final rule clearly requires the 

presence of both bed and banks and another indicator of OHWM, if one is not 

present then the water does not qualify as a tributary. The agencies continue to 

address regional concerns about the identification of the OHWM through the 

development of regional manuals that apply the indicators discussed in the 

regulation and RGL 05-05 to the regional hydrologic and climatic circumstances.

The Wildlife Society (Doc. #14899)

8.193 While we applaud the EPA's inclusion of all tributaries within the jurisdiction of the 

Clean Water Act, we recommend reconsidering the use of the phrase "ordinary high 

 

425 U.S. Army Corps of Engineers, Review of Ordinary High Water Mark Indications for Delineating Arid Streams 

in the Southwestern United States (Robert L. Lichvar and James S. Wakeley eds. 2004).

426 U.S. Army Corps of Engineers, Distribution of Ordinary High Water Mark Indicators and Their Reliability for 

Delineating the Limits of “Waters of the U.S.” in Southwestern Arid Channels (Lichvar et al., 2006).

427 U.S. Environmental Protection Agency, Field Operations Manual for Assessing the Hydrologic Permanence and 

Ecological Condition of Headwater (2006).

428 Emily H. Stanley et al., Ecosystem Expansion and Contraction in Streams. 47 BioScience 427, 427-435 (1997).
Clean Water Rule Response to Comments – Topic 8: Tributaries

385

water mark" (OHWM). By their nature, ephemeral streams, especially those within arid 

and semi-arid environments, and streams in low-gradient landscapes may not have an

OHWM that is readily apparent. The lack of a clearly-apparent OHWM should not 

exclude these tributaries from jurisdictional status, as the connectivity these tributaries 

provide to downstream waters may be brief, but crucial to the physical, chemical, and 

biological integrity of the system. Furthermore, while these waters may not provide a 

perennial surface connection, they often provide a "shallow subsurface hydrologic 

connection" as used in the "neighboring" definition. Therefore, we suggest replacing 

OHWM with the phrase "other evidence of flow". (p. 3)

Agency Response: See response to comments from Southern Environmental Law 

Center et al. (Doc. #13610) above. For a further discussion of the limits of CWA 

jurisdiction in regards to tributaries and the use of OHWM see the summary 

responses 8.1 and 8.1.2 and the TSD.

Potomac Riverkeeper, Inc. (Doc. #15013)

8.194 1. Protect non-wetland, lake or pond tributaries that lack OHWMs. The proposed rule 

only protects tributaries to the extent that they (1) have an ordinary high water mark 

(OHWM); or (2) are wetlands, lakes or ponds. Proposed rule at (u)(5). However, in our 

work, we encounter tributaries-especially in the headwaters of the Shenandoah and 

Potomac-that lack an OHWM. The absence of an OHWM does not in any way diminish 

their importance to safeguarding downstream water quality. (p. 3)

Agency Response: See response to comments from Southern Environmental Law 

Center et al. (Doc. #13610) above. For a further discussion of the limits of CWA 

jurisdiction in regards to tributaries and the use of OHWM see the summary 

responses 8.1 and 8.1.2 and the TSD.

National Wildlife Federation (Doc. #15020)

8.195 1. The agencies’ use of the existing OHWM definition helps clarify the definition of 

tributary and tributary boundaries.

The tributary definition also provides constructive and consistent clarification by 

incorporating and explaining the Corps’ longstanding Ordinary High Water Mark 

(OHWM) as an indicator of channel boundaries. We support the agencies’ use of the 

existing Corps definition of OHWM:

The term “ordinary high water mark” means that line on the shore established by the 

fluctuations of water and indicated by physical characteristics such as a clear, natural 

line impressed on the bank, shelving, changes in the character of soil, destruction of 

terrestrial vegetation, the presence of litter and debris, or other appropriate means that 

consider the characteristics of the surrounding areas. 

33 CFR 328.3(e).

The proposed rule preamble explains that the bed and banks and OHWM requirement is 

important because “these features generally are physical indicators of flow” and thus 

indicative of “a tributary’s ability to transport pollutants to downstream traditionally 

navigable waters, interstate waters, and the territorial seas, and thereby have a significant 
Clean Water Rule Response to Comments – Topic 8: Tributaries

386

effect on the chemical, physical, and biological integrity of a water identified in 

paragraphs (a)(1) through (a)(4).” See 79 Fed. Reg. at 22202. Importantly, the preamble 

notes that these bed and banks and OHWM indicators of flow “can be created by 

ephemeral, intermittent, and perennial flows.” Id.

As the agencies explain, the OHWM “generally defines the lateral limits of a water, and 

its absence generally determines whether a tributary’s channel such that the upper limit of 

the jurisdictional tributary is identified. However, as noted above, we strongly support the 

agencies’ recognition that channel characteristics are variable and those variations must 

be taken into account in evaluating the presence and continuity of the channel bed and 

bank and OHWM. (p. 33)

Agency Response: See response to the comments from Ducks Unlimited (Doc. 

#11014) above and TSD sections 2.A and 7.A.

8.196 2. Any further clarifications of the tributary definition must respect connectivity science 

and the goals of the Clean Water Act, and must not exclude wetlands, lakes, and ponds 

that function as tributaries and are integral elements of the tributary system.

We recognize that the agencies are being asked to further clarify and define the OHWM 

and bed and banks terms in order to provide more consistency and certainty in identifying 

tributaries in the field. At the same time, the SAB is cautioning the agencies to recognize 

that channel characteristics are variable and those variations must be taken into account 

in evaluating the presence and continuity of the channel bed and bank and OHWM. 

Indeed, the SAB is urging EPA to “reconsider the definition of tributaries because not all 

tributaries have ordinary high water marks.” SAB Rule Letter at 2.

As the preamble explains, the Corps has been working to address this variability, 

providing additional technical assistance on this front. See, e.g., 79 Fed. Reg. 22259-10 

citing R.W. Lichvar and S.M. McColley, U.S. Army Corps of Engineers, A Field Guide 

to the Identification of the Ordinary High Water Mark (OHWM) in the Arid West Region 

of the Western United States: A Delineation Manual, ERDC/CRREL TR-08-12 (2008). 

In order to provide additional clarity in applying these terms in the field that is also 

scientifically sound, we recommend that the agencies finalize the definition of tributary 

and the definition of waters of the United States and then continue to develop, adopt, and 

implement regionally-specific OHWM and tributary delineation manuals along the lines 

of the agencies’ regionally-tailored wetland delineation manuals that have been in use for 

decades.

We do not support changes in the tributary definition that sacrifice sound science in an 

effort to draw bright lines. In particular, we oppose the “alternate approach” of 

disqualifying wetlands, lakes, and ponds that are functioning as tributaries simply 

because, by their very nature (their waters do not flow through a defined channel), they 

do not necessarily have a bed and bank and OHWM. See, 79 Fed. Reg. 22203. Just as 

linearly flowing tributaries are defined by bed, bank, and OHWM, wetlands are defined, 

through an established wetland delineation methodology, by the “3-parameter test:” the 

presence of hydric soils (which take years to develop), the presence of hydrology during 

the growing season, and the presence (under normal circumstances) of hydrophytic 

vegetation. Similarly, lakes and ponds are characterized by the relatively permanent 

presence of a lake or pond bed and open water. These established, relatively permanent 
Clean Water Rule Response to Comments – Topic 8: Tributaries

387

water bodies are critical elements of the tributary system and must continue to be 

recognized as such and found to be jurisdictional on that basis. (p. 33-34)

Agency Response: See response to comment from California Association of 

Winegrape Growers (Doc. #14593) above. 

American Rivers (Doc. #15372)

8.197 1. Clarify the Definition of Tributary

We believe that the definition of “tributary” should be further clarified. In order to ensure 

a protective and comprehensive application of the proposed rule, the definition of 

“tributary” and subsequent interpretations throughout the proposed rule should not 

primarily rely upon the presence of bed, banks, and ordinary high water mark 

(“OHWM”). Although the existence of bed and banks and OHWM can assist in 

demonstrating the presence of a tributary, these physical features should not be a 

prerequisite for the determination that a surface water feature is a tributary and therefore 

jurisdictional.

The proposed rule defines a tributary, in part, using physical characteristics, including 

those waters physically characterized by “the presence of a bed and banks and ordinary 

high water mark, as defined at 33 CFR 328.3(e), which contributes flow, either directly or 

through another water, to a water identified in paragraphs (a)(1) through (4).”429 While 

presenting these physical determinants of a tributary, the proposed rule simultaneously 

recognizes “wetland, lakes, and ponds, are tributaries (even if they lack a bed and banks 

and OHWM), if they contribute flow.”430 The proposed rule also recognizes that a water 

continues to qualify as a tributary if, for any length, there are natural or manmade breaks 

“so long as a bed and banks and an ordinary high water mark can be identified upstream 

of the break.”431 While we agree that these waters should be protected, these statements 

create confusion as to the importance of the identified physical features of bed and banks 

and OHWM in the determination of whether or not a waterway is a tributary. The first 

deemphasizes these physical characteristics, while the latter accentuates their importance. 

Additionally, the proposed rule notes that the “OHWM generally defines the lateral limits 

of water, and its absence generally determines whether a tributary’s channel or bed and

banks has ended such that the upper limit of the jurisdictional tributary has ended.”432

The use of the term “generally” brings ambiguity without further specification of when 

the OHWM does and does not denote a tributary. The lack of clarity regarding the 

importance of defining physical features will make determinations of whether or not a 

water is a tributary, and therefore jurisdictional by rule, difficult in practice in the arid 

west.

Of most concern are potential cases where a water would not meet the definition of a 

tributary based on the absence of bed and banks and OHWM, but could reasonably be 

considered one based on contributing perennial, intermittent, or ephemeral flow and 

 

429 Definition of WOTUS, 79 Fed. Reg. at 22201.

430 Id.

431 Id.

432 Id. at 22202 (emphasis added).
Clean Water Rule Response to Comments – Topic 8: Tributaries

388

presence of physical, chemical, or biological characteristics indicative of flow and 

connectivity.433 For example, and as noted by the Agencies in the proposed rule, in low 

gradient systems and dry-land systems, the presence of an OHWM or bed and banks may 

be difficult to observe or discontinuous.434 Intermittent and ephemeral streams will not 

always have an obvious OHWM because, “the climate of the region drastically influences 

the hydrology, channel-forming processes, and distribution of OHWM indicators such 

that delineations can be inconsistent (over space and time) and problematic.”435 The 

Corps notes that the, “OHWM delineation in non-perennial streams (i.e., intermittent and 

ephemeral) can be especially challenging.”436 Despite the potential lack of these physical 

features, intermittent and ephemeral streams impact the physical, biological, and 

chemical integrity of downstream waters and should be jurisdictional.437

We propose that the Agencies revise this definition to ensure that, while bed, banks, and 

OHWM are physical features that aid in the identification of a tributary, they are not

attributes necessary to the determination that a waterway is a tributary. We recommend 

the Agencies use the following definition, which is used in the proposed rule as a 

clarifying statement, that a tributary is a “longitudinal surface feature that results from 

directional surface water movement and sediment dynamics.”438 The Agencies should 

further add that bed, banks, and OHWM can be indicators of directional surface water 

movement and sediment dynamics. This revised definition would deemphasize the 

mandatory presence of certain physical features and focus on whether or not the water 

body contributes downstream flow and how it functions within the watershed.

 

433 The Scientific Advisory Board has a similar concern. SAB review of the proposed rule, supra note 89 at 2.

434 Definition of WOTUS, 79 Fed. Reg. at 22202.

435 Robert W. Lichvar and Shawn M. McColley, U.S. Army Corps of Engineers, Engineer Research and

Development Center, Cold Regions Research and Engineering Laboratory, ERDC/CRREL TR-08-12, A Field Guide

to the Identification of the Ordinary High Water Mark (OHWM) in the Arid West Region of the Western United

States (Army Engineer Research and Development Center, 2008), available at http://www.spk.usace.army.mil/

Portals/12/documents/regulatory/pdf/Ordinary_High_Watermark_Manual_Aug_2008.pdf.

436 Matthew K. Mersel, Robert W. Lichvar, Jennifer J. Gillrich, and Lindsey E. Lefebvre, U.S. Army Corps of

Engineers, Engineer Research and Development Center, Cold Regions Research and Engineering Laboratory,

ERDC/CRREL TR-14-11, Occurrence and Distribution of Ordinary High Water Mark (OHWM) Indicators in NonPerennial Streams in the Western Mountains, Valleys, and Coast Region of the United States (U.S. Army Engineer

Research and Development Center, Aug. 2014), available at http://acwc.sdp.sirsi.net/client/search/asset /103602.

American Rivers recognizes the guidance documents that the Corps issued in August 2014 to help delineate

OHWMs, however these documents do not adequately address our concerns and we still believe that tributaries 

should not be defined by whether they have an OHWM or not. For example, the report “Occurrence and Distribution

of Ordinary High Water Mark (OHWM) Indicators in Non-Perennial Streams in the Western Mountains, Valley, and

Coast Region of the United States,” is focused in the Western part of the U.S. and the findings may not be applicable 

to other regions. As noted in the report, “How the OHWM and its physical indicators vary spatially and temporally 

in the rest of the United States remains largely unexplored.” See also, Matthew K. Mersel, Robert W. Lichvar, and

Lindsey E. Lefebvre, U.S. Army Corps of Engineers, Engineer Research and Development Center, Cold Regions

Research and Engineering Laboratory, ERDC/CRREL TR-14-12, A Review of Land and Stream Classificaitons in

Support of Developing a National Ordinary High Water Mark (OHWM) Classification (U.S. Army Engineer 

Research and Development Center, Aug. 2014) available at http://acwc.sdp.sirsi.net/client/search/asset/1036026.

437 U.S. EPA, Office of Research and Development, EPA/600/R-11/098B, Connectivity of Streams and Wetlands to

Downstream Waters: A Review and Synthesis of the Scientific Evidence (U.S. EPA, Office of Research and

Development, 2013).

438 Definition of WOTUS, 79 Fed. Reg. at 22202.
Clean Water Rule Response to Comments – Topic 8: Tributaries

389

Additionally, in making these determinations, the best available information should 

always be used. The proposed rule states that these determinations can be made using 

“direct observation or U.S. Geological Survey maps, aerial photography, or other reliable 

remote sensing information, or other appropriate information.”439 While these are 

important sources of information, the proposed rule should include language that requires 

the Agencies to use the best available information to ensure the most accurate 

determinations of CWA jurisdiction are made. (p. 18-20)

Agency Response: The agencies are committed to using the best information 

available to make decisions. See response to comment from California Association 

of Winegrape Growers (Doc. #14593) above for discussion of the definition of 

tributary in the final rule.

Western Resource Advocates (Doc. #16460)

8.198 Tributaries (including ditches) without an Ordinary High Water Mark

The proposed rule would, for the most part, consider only tributaries with an ordinary 

high water mark (OHWM) as jurisdictional. In the headwaters of the states where WRA 

works, there are often wetlands and lakes at the extreme headwaters of watersheds that 

contribute high quality water to their systems and require protection. Rocky Mountain 

National Park in Colorado has many examples of tarns, beaver meadows and other 

features that lack an OHWM but whose waters are substantially connected to, and 

therefore their quality must be protected to maintain the chemical, biological and physical 

integrity of our nation’s waters.

The proposed rule seeks public comment as to whether these waters should be 

jurisdictional as tributaries or as adjacent waters. WRA does not advocate one approach 

over the other, provided that the outcome keeps these waters jurisdictional without the 

need for a case-by-case review. (p. 15-16)

Agency Response: See response to comment from California Association of 

Winegrape Growers (Doc. #14593) above.

National Waterways Conference, Inc. (Doc. #12979)

8.199 While a bed, banks and OHWM can be easily identified in some locations, in others those 

features are not evident, especially an OHWM. Despite that difficulty, the proposed rule 

would deem any area with those features to be jurisdictional. Realistically, that has the 

potential to require examination of miles of upstream tributary features both at the project 

site and between there and a traditionally navigable waterway. The applicant may not 

even have access to the entire area due to legal or physical constraints.

The agencies themselves do not yet fully understand the potential reach associated with 

extending jurisdiction based on these features. In August 2014, well into the comment 

period for this rulemaking, the Corps released two new documents pertaining to OHWM 

determinations, one of which readily acknowledges a "need for nationally consistent and 

 

439 Id.
Clean Water Rule Response to Comments – Topic 8: Tributaries

390

defensible regulatory practices."440 That can only mean that the Corps' own experts in this 

area would concede that today's practices have not proven to be nationally consistent and 

defensible. In fact, the Corps has produced an entire report with the stated objective of 

determining "the most appropriate factors to include in a national OHWM 

classification.”441 As the factors to be used in identifying OHWM have yet to be 

determined, the agencies may not credibly claim that the proposed rule provides 

clarification or that is does not expand jurisdiction. (p. 9-10)

Agency Response: See response to comment from Nucor Corp. (Doc. #14963 and 

summary response 8.1.2 above.

Earthjustice (Doc. #14564)

8.200 Subsection (s)(5) must be read in conjunction with the definition of tributaries in 

subsection (u)(5). While the definition is a good start, as noted in EPA’s Connectivity 

Report and by a number of the individual members of the SAB review panel, it is too 

limiting and therefore not fully in keeping with the science of tributaries and how/when 

they affect downstream waters. See USEPA Office of Research and Development, 

“Connectivity of Streams and Wetlands to Downstream Waters: A Review and Synthesis 

of the Scientific Evidence,” External Review Draft (Sept. 2013) at 1-6 (“All tributary 

streams, including perennial, intermittent, and ephemeral streams, are physically, 

chemically, and biologically connected to downstream rivers via channels and associated 

alluvial deposits where water and other materials are concentrated, mixed, transformed, 

and transported”) and 1-7 to 1-8 (and related chapters) (hereinafter “Connectivity 

Report”). In particular, the limitation requiring bed, banks and an ordinary high water 

mark (unless it is a wetland, lake or pond) may exclude some waters from protection that 

plainly affect downstream waters and that could then result in pollutants to downstream 

waters. One SAB member comment suggests, for stream (lotic) tributaries, that it should 

state “bed and bank, and sometimes an [ordinary high water mark]” in order to capture 

groundwater fed streams that are temporally stable. Member Comments, Aldous at 3. See 

also, Member Comments Kolm at 31 and 32; Rosi-Marshall at 81 (“Indeed, scientific 

research has shown that flows that occur intermittently, e.g. during a flood or spring 

snowmelt, can exert a strong influence on downstream systems. A definition of tributary 

that includes these small but extremely important systems.....is necessary” and “These 

chains of aquatic habitats can be thought of as beads on a string that can act in concert to 

influence the biological integrity of downstream waters”); and Sullivan at 85. (p. 6)

Agency Response: See response to comment from California Association of 

Winegrape Growers (Doc. #14593) above.

 

440 Matthew K. Mersel, Lindsey E_ Lefebvre, and Robert W, Lichvar, U,S, Army Engineer Research and 

Development Center (ERDC), A Review of Land and Stream Classifications in Support of Developing a National 

Ordinary High Water Mark Classification, at 1-2 (August 2014) (hereinafter "OHWM Classification Review"); see 

also Matthew K. Mersel and Robert W, Lichvar, U,S, Army Engineer Research and Development Center (ERDC), 

A Guide to Ordinary High Water Mark (OHWM)

441 OHWM Classification Review, supra note 36, at 3.
Clean Water Rule Response to Comments – Topic 8: Tributaries

391

Center for Rural Affairs (Doc. #15029)

8.201 The proposed rule defines ordinary high water mark (OHWM) by reference only, 

directing readers to 33 CFR 328.3(e) and the following definition: “The term ordinary 

high water mark means that line on the shore established by the fluctuations of water and 

indicated by physical characteristics such as clear, natural line impressed on the bank, 

shelving, changes in the character of soil, destruction of terrestrial vegetation, the 

presence of litter and debris, or other appropriate means that consider the characteristics 

of the surrounding areas.”

The EPA and the Corps should incorporate this definition into the proposed rule. Failing 

to include this definition in the rule requires readers to dig deeper for a term that is 

integral to the rule’s implementation—an unnecessary hoop through which the regulated 

community must jump. This simple solution reiterates and solidifies one of the criteria for 

the definition of tributary, and could help alleviate the regulated community’s concerns 

that temporary, precipitation-induced hydrologic features lacking an OHWM would be 

jurisdictional.

Recommendation: Include the definition of ordinary high water mark in the proposed 

rule to provide greater clarity and easier access to key terms. (p. 3)

Agency Response: The final rule incorporates the long standing definition of 

OHWM as suggested. 

Texas Wildlife Association (Doc. #12251)

8.202 The Proposed Rule Fails to Provide Clarity or Predictability

...using the confusing concept of ordinary high water mark (OHWM) as the key 

identifier for tributaries... (p. 3)

Agency Response: See response to comment from California Association of 

Winegrape Growers (Doc. #14593) above.

Protect Americans Now (Doc. #12726)

8.203 ... Because tributary is identified by the presence of "a bed and banks and ordinary high 

water mark" and its contribution of "flow, either directly or through another water," it 

may capture an untold number of ephemeral streams and similar conveyances caused by 

erosion. These features are common in the west. Accordingly, jurisdiction will be 

extended to lands that possess waters only a few times during the year, and lands that 

may or may not actually contain a connection, significant or otherwise, to (a)(I) through 

(a)(4) waters. The impact of automatically including these waters could be dramatic to 

the farmers and ranchers who work the ranges of the western United States. Because the 

determination is automatic, the costs of complying with permitting and restrictions should 

be more properly analyzed. Ephemeral and intermittent waters and erosional features that 

lack permanent surface water connections should be exempted from any proposed 

definition of "tributary.” (p. 14)

Agency Response: See responses to the two comments from Alameda County 

Cattlewomen (Doc. #8674) above and summary response 8.1.2 above for discussion 
Clean Water Rule Response to Comments – Topic 8: Tributaries

392

of tributaries and response to comments compendium 11 on Costs and Benefits for 

discussion of the economic analysis. 

Citizens Committee to Complete the Refuge (Doc. #14738.1)

8.204 We do take issue with the proposed reliance on the presence of an Ordinary High Water 

Mark (OHWM) as an indicator of the extent of Corps jurisdiction within tributaries. A 

September 30, 2014 letter from Dr. David T. Allen, Chair of the Science Advisory Board 

(SAB) to EPA, expressed the SAB recommendation that EPA:

"...reconsider the definition of tributaries because not all tributaries have ordinary 

high water marks. An ordinary high water mark may be absent in ephemeral 

streams within arid and semi-arid environments or in low gradient landscapes 

where the flow of water is unlikely to cause an ordinary high water mark. The 

Board advises the agency to consider changing the wording in the definition to 

“bed, bank, and other evidence of flow.”

We urge EPA to adopt the recommendations of the SAB, and to replace OHWM with 

"bed, bank, and other evidence of flow." (p. 2)

Agency Response: See response to comment from California Association of 

Winegrape Growers (Doc. #14593) above.

Los Angeles Waterkeepers (Doc. #15060)

8.205 ...we urge EPA and the Corps to carefully reconsider all implications of the Proposed 

Rule’s language, in particular its effect on jurisdictional waterbodies that the EPA and the 

Corps have historically protected and intend to regulate under the Proposed Rule, as 

indicated in the preamble.442 Specifically, we urge EPA and the Corps to amend the 

Proposed Rule’s “ordinary high water mark” requirement for tributaries.

Due to its arid environment and extensive network of heavily engineered, channelized 

waterways, the Los Angeles region is home to many tributaries that are at risk of losing 

regulatory protections as a result of the Proposed Rule’s definition of “tributary.” 

Although the science supports the conclusion that all tributaries are physically, 

chemically, and biologically connected to downstream rivers,443 it could be prohibitively 

burdensome, if not impossible, to demonstrate an “ordinary high water mark” in some 

tributaries, as is required by the Proposed Rule’s definition of tributary. In fact, the SAB 

has explicitly informed EPA that ordinary high water marks may be absent in ephemeral 

streams within arid and semi-arid environments or in low gradient landscapes.444 Thus, 

 

442 See Proposed Rule, 79 Fed.Reg. 22,188, 22,202 (proposed April 21, 2014) (“The agencies identified these 

tributary characteristics as indicative that the water is the type of hydrologic feature protected under the CWA 

because, for example, of a tributary’s ability to transport pollutants to downstream traditional navigable waters, 

interstate waters, and the territorial seas, and thereby have a significant effect on the chemical, physical, or 

biological integrity of a water identified in paragraphs (a)(1) through (a)(4).”); see also id. at 22,202 (“Longstanding 

agency practice has identified tributaries as including ‘‘natural, man-altered or manmade’’ water bodies.”) 4 

Connectivity Report, Executive Summary, 1-3.

443 Connectivity Report, Executive Summary, 1-3.

444 U.S. Environmental Protection Agency, Science Advisory Board, Consideration of the Adequacy of the Scientific
Clean Water Rule Response to Comments – Topic 8: Tributaries

393

the finalized rule should incorporate the Scientific Advisory Board’s (“SAB”) 

recommendation that tributaries be defined by “bed, bank, and other evidence of 

flow.”

To illustrate, many tributaries to the Los Angeles River and other local jurisdictional

waters are characterized by wide, low-gradient concrete beds and steep concrete banks 

with varying degrees of low-level flows throughout most of the year and intermittent 

heavy flows during periods of rainfall.445 Those tributaries’ characteristics prevent the 

formation of “[a] clear, natural line impressed on the bank, [formation of] shelving, 

changes in the character of soil, [or] destruction of terrestrial vegetation” and possibly 

prevent any other means of demonstrating a high water line.446 Nonetheless, the scientific 

literature available to EPA and the Corps support the conclusion that such tributaries to 

the Los Angeles River and other local jurisdictional waters have the requisite impact on 

the chemical, physical, and biological integrity of the waters into which they eventually 

flow447 to necessitate protection under the Clean Water Act.448

Therefore, in light of the scientific literature available to the agencies, EPA and the Corps 

should incorporate the SAB’s recommendation that the agencies revise the Proposed 

Rule’s “tributary” definition.10 Specifically, to ensure the Proposed Rule’s effect is 

consistent with the available science and the agencies’ intent, the Proposed Rule’s 

definition of the term tributary must be revised to read “a water physically characterized 

by the presence of a bed and banks and other evidence of flow . . . .” (p. 3-4)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. The final rule clearly 

requires the presence of both bed and banks and another indicator of OHWM, if 

one is not present then the water does not qualify as a tributary. The Connectivity 

Report supports the scientific conclusion that all features that meet this definition of 

tributary impact the physical, chemical, and biological integrity of downstream 

waters and therefore have a significant nexus to (a)(1) through (3) waters. For a 

discussion of the limits of CWA jurisdiction in regards to tributaries and the use of 

OHWM see the summary responses 8.1 and 8.1.2 and the TSD.

Delaware Riverkeeper Network (Doc. #15383)

8.206 Science supports making all tributaries jurisdictional under the CWA. For this reason, the 

definition of a tributary should not include the requirement of an ordinary high water 

mark as not all tributaries have high water marks.449 Instead, the definition of a tributary 

 

and Technical Basis of the EPA’s Proposed Rule titled “Definition of Waters of the United States under the Clean 

Water Act, EPA-SAB-14-007 (Sept. 30, 2014), 2.

445 Compton Creek and Dominguez Channel and prime examples of such waterbodies. See Attachment A.

446 See 33 CFR § 328.3(e).

447 See Proposed Rule, 79 Fed.Reg. 22,188, 22,201 (proposed April 21, 2014) (“Tributaries have a significant impact 

on the chemical, physical, and biological integrity of waters into which they eventually flow . . . .”); see also id. at 

22202 (“A tributary . . . can be a natural, man-altered, or man-made water and includes waters such as rivers, 

streams, lakes, ponds, impoundments, canals, and ditches not excluded in paragraph (b)(3) or (4).”).

448 Connectivity Report, Executive Summary, 1-3.

449 Letter from the Science Advisory Board to The Honorable Gina McCarthy, Administrator of the EPA (Sept. 30, 

2013).
Clean Water Rule Response to Comments – Topic 8: Tributaries

394

should include “bed, bank, or other evidence of flow” in place of “high water mark”. (p. 

3)

Agency Response: See response to comment from Los Angeles Waterkeepers 

(Doc. #15060) above.

Missouri and Associated Rivers Coalition (Doc. #15528)

8.207 2. The definition proposed for "tributary" creates uncertainty and relies on newly released 

Technical guidance for identifying tributaries.

The proposed definition of "tributary" - which requires only a bed, banks and an ordinary 

high water mark ("OHWM") - will create uncertainty in many instances. While a bed, 

banks and OHWM can be easily identified in some locations, in others those features are 

not evident, especially an OHWM. The proposed rule would nevertheless make a 

tributary a "waters of the U.S." if, at any upstream location, a bed, banks and OHWM can 

be identified. Such a broad definition will potentially require examination of miles of 

upstream tributary features, quite possibly beyond areas that are accessible either due to 

legal or physical constraints, The proposed rule's reliance on being able to define and 

identify an OHWM to determine jurisdiction over tributaries does not provide clarity as 

there has not been established a reliable and repeatable means to identify an OWHM. Just 

shortly after the proposed rule was published in April 2014, the Corps of Engineers 

released new technical guidance (ERDC/CCREL TR-14-13, A Guide to Ordinary High 

Water Mark (OHWM) Delineation for Non-Perennial Streams in the Western Mountains, 

Valleys, and Coast Region of the United States) for delineating the OHWM in nonperennial streams in the Western U.S. The EPA has stated publicly that similar guidance 

is being developed for other regions. The Corps also released in August 2014, 

(ERDC/CCREL TR-14-12, A Review of Land and Stream Classifications in Support of 

Developing a National Ordinary High Water Mark (OHWM) Classification) a report with 

the objective of determining the "most appropriate factors to include in a national 

OHWM classification." As the factors to be used in identifying OHWM's have yet to be 

determined it is blatantly false to claim that the proposed rule provides clarification and 

does not expand jurisdiction. (p. 3)

Agency Response: See response to comment from Nucor Corp. (Doc. #14963 and 

summary response 8.1.2 above.

Defenders of Wildlife and Patagonia Area Resource Alliance (Doc. #16394)

8.208 Although the inclusion of tributaries in the proposed definition of “waters of the U.S.” is 

scientifically sound and consistent with the purpose and intent of the Clean Water Act, 

we also note that the definition is too limiting. In particular, the limitation to tributaries 

with ordinary high water marks excludes some tributaries that will affect waters 

downstream. Eliminating this limitation would be consistent with SAB’s 

recommendation. “The Board advises the EPA to reconsider the definition of tributaries 

because not all tributaries have ordinary high water marks. An ordinary high water mark 

may be absent in ephemeral streams within arid and semi-arid environments or in low 

gradient landscapes where the flow of water is unlikely to cause an ordinary water mark. 

The Board advises the agency to consider changing the wording in the definition to ‘bed, 

bank, and other evidence of flow.’” SAB letter at 2. In the California Desert, the stream 
Clean Water Rule Response to Comments – Topic 8: Tributaries

395

banks of a waterway can be slight or nearly imperceptible, and hence the degree of 

channel confinement can vary along the line of flow. According to the California 

Department of Fish and Wildlife in a review of Dryland Water ways, “[w]hile the 

hydrologic controls are fundamentally the same in dryland regions as those of temperate 

and humid areas the pronounced distribution and temporal intensity and discontinuities in 

runoff volumes and durations for dryland streams lead to a much less ordered pattern of 

processes and stream forms (Thornes 2009). As a consequence, dryland streams are often 

outside the normal range of the hydrologic and morphologic characteristics of their 

temperate and humid region counterparts, and their hydrology, sediment transport 

characteristics, and resultant channel forms characteristics, and resultant channel forms.” 

A Review of Stream Processes and Forms in Dryland Watersheds, California Department 

of Fish and Game, Prepared by Kris Vyverberg, Senior Engineering Geologist 

Conservation Engineering, December 2010, at p. 5.

In addition, the physical characteristics – scour lines, flood debris, etc. – used to delimit 

waters are left by frequently recurring floods, whereas riparian functions can be 

supported by less frequent floods. In the East, this is unimportant because seasonal and 

annual flow variations are muted. For example, the increase in flow between the one-year 

and 50-year flood in a Pennsylvania watershed is 2.5 times (i.e., the 50-year flood carries 

2.5 times as much water as the one-year flood). Western dryland systems, however, are 

much more variable. The same figure in a dryland stream is 280, and in small southern 

California dryland basins the 50-year flood may carry 400 times as much water as the 

one-year flood. Western riparian vegetation has adapted to establish and survive in 

portions of the floodplain inundated relatively infrequently, beyond the boundary of 

physical characteristics left by the frequent flood events and hence outside of Clean 

Water Act jurisdiction. Aaron Allen and D. Malanchuk, Guidelines for Jurisdictional 

Determinations for Waters of the United States in the Arid Southwest, June 2001, 

USACOE, South Pacific Division; and Allen, A., remarks at 5th Annual California 

Regulatory Coordination Conference, USCOE South Pacific Division, Sacramento, 

California, December 18, 2002. These dynamic hydrologic regimes should also be 

subject to Clean Water Act protection. (p. 7)

Agency Response: See response to comments from Southern Environmental Law 

Center et al. (Doc. #13610) above. For a further discussion of the limits of CWA 

jurisdiction in regards to tributaries and the use of OHWM see the summary 

responses 8.1 and 8.1.2 and the TSD.

Waterkeeper Alliance et al. (Doc. #16413)

8.209 ...the agencies should not narrow jurisdiction over tributaries through the adoption of a 

mandatory requirement for tributaries to possess a bed, bank, and Ordinary High Water 

Mark ("OHWM"). The existence of an OHWM should not be a requirement for asserting 

jurisdiction over tributaries, as it is not supported by law and science. As noted in the 

Connectivity Report and the Member Comments, the requirement of an OHWM 

improperly limits jurisdiction, and is not consistent with the science regarding how 

tributaries are affected by pollution or how tributaries impact downstream waters.
Clean Water Rule Response to Comments – Topic 8: Tributaries

396

The Proposed Definition incorporates the definition of OHWM from existing' regulations 

developed for the CWA Section 404 Program into the definition of tributary. The 

definition is taken from 33 C.F.R. 328.3(e) which provides:

The term ordinary high water mark means that line on the shore established by the 

fluctuations of water and indicated by physical characteristics such as a clear, 

natural line impressed on the bank, shelving, changes in the character of soil, 

destruction of terrestrial vegetation, the presence of litter and debris, or other 

appropriate means that consider the characteristics of the surrounding areas.

While this definition may have some reasonable meaning in the context of determining 

the boundaries of waters where dredge and fill activities are proposed, it has nothing to 

do with the extent of "waters of the United States" in the context of regulating and 

responding to the discharge of pollutants. As the Corps noted in 1977:

Prior to enactment of the FWPCA, the mean tide line or (mean higher tide line on 

the West Coast) was used to delineate the shoreward extent of jurisdiction over 

the regulation of most activities in tidal waters under the 1899 Act as well as for 

mapping, delineation of property boundaries, and other related purposes. In 

freshwater lakes, rivers and streams that are navigable waters of the. United 

States, the landward limit of Jurisdiction has been traditionally established at the 

ordinary high water mark. The regulation of activities that cause water pollution 

cannot rely on these artificial lines, however, but must focus on all waters that 

together form the entire aquatic system. Water moves in hydrologic cycles, and 

the pollution of this part of the aquatic system, regardless of whether it is above or 

below an ordinary high water mark, or mean high tide line, will affect the water 

quality of the other waters within that aquatic system.450

Thus, the concept of an OHWM or High Water line was utilized in the context of the 

Rivers and Harbors Act of 1899 and jurisdictional consideration related to traditional 

navigability where "[t]he need to protect navigable capacity of a waterway above the 

mean high water line was obviously minimal."451 The inapplicability of this limitation to 

the CWA was addressed in the Holland case which outlined both the authority and need 

to regulate waters beyond the reach of the traditional navigability tests and stated that "to 

recognize this and yet hold that pollution does not affect interstate commerce unless 

committed in navigable waters below the mean high water line would be contrary to 

reason."452

These long-held views as to the inapplicability of the OHWM to the meaning of "waters 

of the United States" under the CWA are confirmed by the Connectivity Report which 

further provides that "[a]ll tributary streams, including perennial, intermittent, and 

ephemeral streams, are physically, chemically, and biologically connected to downstream 

rivers via channels and associates alluvial deposits where water and other materials are 

concentrated, mixed, transformed, and transported.”453 There is nothing in the 

 

450 42 Fed. Reg. 37122, 37128 (July 19, 1977).

451 Holland, 373 F. Supp. at 670-673.

452 Id.

453 Connectivity Report, supra note 3, at 1-3, and related Chapters.
Clean Water Rule Response to Comments – Topic 8: Tributaries

397

Connectivity Report to support the idea that these connections are limited to tributaries 

with OHWMs or that OHWMs are the sole indicator of connectivity. Individual SAB 

members also expressed disagreement or concern with the addition of a requirement for 

an OHWM for tributaries. For example, on member stated that:

The definition of the lotic-type tributary is appropriately comprehensive because 

it inherently includes ephemeral and intermittent streams (as well as perennial) 

streams. The former types are often overlooked but ecologically important, 

particularly in arid landscapes with seasonal patterns of precipitation. However, 

there may be some types of tributaries, such as spring-fed streams, that lack an 

obvious OHWM because their groundwater sources dominate the water budget, 

are temporally stable, and so there is no fluctuation in the hydrograph to generate

a 'line on the shore established by the fluctuations of water and indicated by 

physical characteristics such as a clear line on the banks .. .' Therefore the 

definition should be 'bed and bank, and sometimes an OHWM.'454 (p. 30-32)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. As described in the 

summary responses 8.1 and 8.1.2, the final rule clearly requires the presence of both 

bed and banks and another indicator of OHWM, if one is not present then the water 

does not qualify as a tributary. The agencies continue to address regional concerns 

about the identification of the OHWM through the development of regional 

manuals that apply the indicators discussed in the regulation and RGL 05-05 to the 

regional hydrologic and climatic circumstances. For a further discussion of the 

limits of CWA jurisdiction in regards to tributaries and the use of OHWM see the 

summary responses 8.1 and 8.1.2 and the TSD.

Congress of the United States, Senate Committee on Environment and Public Works et al. (Doc. 

#16564)

8.210 The proposed "waters of the United States" rule designates "tributaries" as jurisdictional 

per se.455 "Tributary," however, does not mean "a stream feeding a larger stream or a 

lake," as one would understand this term in normal parlance.456 Instead, EPA and the 

Corps have proposed a sweeping definition for "tributary"457:

...

 Landowners will face a significant challenge in determining whether a water is 

"physically characterized by the presence of a bed and a banks and [OHWM]." In 

making this determination, they must keep in mind that the Corps' prior OHWM 

assessments have "extended ' the waters of the United States' to virtually any land 

 

454 Member Comments, supra note 72, Aldous at 2-3 (internal citations omitted).

455 Definition of "Waters of the United States" Under the Clean Water Act, 79 Fed. Reg. 22 188, 22262-22263

(proposed April 21, 20 14) (hereinafter, " Proposed Rule") .

456 See Webster's New Collegiate Dictionary 1238 (Merriam-Webster 1979).

457 See Proposed Rule, 79 Fed. Reg. at 22263.
Clean Water Rule Response to Comments – Topic 8: Tributaries

398

feature over which rainwater or drainage passes and leaves a visible mark even if 

only the presence of litter and debris."458

 If water can be traced from a TNW upstream to a local wetland, lake, or pond, 

that alone is sufficient to bring these water features within the definition of 

"tributary," even if they lack a bed and banks or OHWM. This standard puts those 

who own land containing wetlands, lakes, or a pond on notice that their property 

will likely constitute "waters of the United States" if the proposed rule is 

finalized. 

... (p. 3, 4)

Agency Response: See response to comment from California Association of 

Winegrape Growers (Doc. #14593) above.

O'Neil LLP (Doc. #16559)

8.211 The Proposed Rule needs to clarify the term "Ordinary High Water Mark" to be clear to 

the public that this term, as used in the Rule, is not being expanded by the Agencies. On 

the bottom of page 22259 and then on page 22260, the Proposed Rule references 

"technical assistance for problematic OHWM delineations" and references the document 

R.W. Lichvar and S.M. McColley, U.S. Army Corps of Engineers, A Field Guide to the

Identification of the Ordinary High Water Mark (OHWM) in the Arid West Region of the 

Western United States: A Delineation Manual ERDC/CRREL TR-08-12 (2008) as 

official guidance. This manual has not been subject to notice and comment rulemaking, 

but it expands jurisdiction in the Arid West to the ten-year area of the floodplain. Any 

such expansion of jurisdiction should be identified first to the public and considered only 

after the public has had an opportunity to review and comment on the merits of such an 

expansion. Furthermore, no such expansion ought to be allowed by the agencies which 

would go beyond the boundaries established by Congress in the definition of "waters" 

regulated by the terms of the CWA. (p. 5)

Agency Response: See response to comment from Nucor Corp. (Doc. #14963 and 

summary response 8.1.2 above. 

8.2. INCLUSION OF WETLANDS, LAKES, DITCHES AS TRIBUTARIES

Agency Summary Response

The proposed definition of “tributary” indicated that a water must have a bed, banks, and 

ordinary high water mark (OHWM), and also provided that wetlands, lakes, and other waters 

without these physical characteristics could nonetheless be considered a tributary so long as they 

contributed flow to a TNW, interstate water, or territorial sea. Wetlands typically lack bed and 

banks and OHWM, while lakes and ponds typically have an ordinary high water mark and a bed 

but may lack banks. The proposed rule expressly sought comment on whether wetlands, ponds, 

 

458 Rapanos v. United Stales, 547 U.S. 7 15, 725 (Scalia. J., plurality opinion) (internal quotations and citation

omitted).
Clean Water Rule Response to Comments – Topic 8: Tributaries

399

and lakes should be considered tributary, or alternatively such waters should be evaluated as 

adjacent waters. 

Issue: Wetlands, Lakes, and Ponds 

A majority of commenters called for wetlands to be excluded from the tributary definition 

because they generally do not have a bed, banks, and OHWM. If the tributary definition 

included such waters, several argued, the definition would contradict itself by defining tributary 

using physical requirements while simultaneously waiving those physical requirements for some 

waters. Inclusion of wetlands, several commenters asserted, would effectively rescind any 

clarity provided by the bed, banks, and OHWM criteria. Other commenters emphasized that 

“tributary” by many is considered to mean moving water and treating wetlands, ponds, or lakes 

as tributaries could create confusion for regulated communities. Some commenters noted that 

under the proposed definition of tributary, lakes and ponds may be jurisdictional even if they 

only contain water when there is nearby rain or snowmelt. This could create confusion because, 

unlike wetlands which contain specialized vegetation even when dry, ponds and lakes need not 

have such vegetation. As a result, a definition of tributary that included ponds and lakes would 

have uncertain limits and potentially substantially increase the scope of jurisdiction. Some 

commenters noted that a “connection” to downstream waters should not lead to a wetland, lake, 

or pond being tributary, since all wetlands, lakes, and ponds at full retention capacity within their 

basin will overtop upland and contribute flow. These commenters recommended any evaluation 

consider the water’s connectivity under normal circumstances.

Many commenters called instead for wetlands, lakes and ponds that lack bed and banks, or 

OHWM, to be evaluated as an adjacent water. Several indicated that such lentic-type (not 

flowing; still) waters are more appropriately considered as adjacent. Some recommended that 

such waters need a case-specific significant nexus analysis in order to be jurisdictional, even if 

evaluated as adjacent. Others noted that adjacency was the appropriate way to protect headwater 

wetlands, without indicating whether such protection should be per se or after an affirmative 

significant nexus evaluation.

Some commenters supported the inclusion of wetlands in the definition of tributary, noting that 

requiring bed and banks would exclude important headwater areas that provide flow but also are 

important as headwater wetlands.

The final rule does not consider ponds, lakes, and wetlands to be tributaries. Instead, the final 

rule defines adjacent waters to include wetlands, lakes, and ponds that connect segments of 

tributaries or at the head of the tributary system. The proposed rule expressly sought comment 

on whether wetlands, lakes, and ponds should be considered tributary or as adjacent waters, 

recognizing that it might add an element of uncertainty to the definition of “tributary” to include 

such waters that lacked the physical features called for by the definition. As summarized above, 

public comments overwhelmingly indicated that it was confusing to consider wetlands, lakes, 

and ponds as tributary. In addition, the Science Advisory Board commented that tributaries are 

not typically defined to include lentic systems, and suggested that the agencies reconsider 

including ponds, lakes, and wetlands as adjacent waters instead of tributaries. For more 

discussion, see Compendium 3 on Adjacency, and the Technical Support Document.
Clean Water Rule Response to Comments – Topic 8: Tributaries

400

Issue: Ditches as Tributary 

Several commenters discussed ditches as part of their discussion of whether wetlands, lakes, and 

ponds should be considered as tributaries. Many noted that ditches should be excluded from the 

definition of tributary altogether, because they might or might not be hydrologically connected to 

another feature and so cannot always be presumed to have a significant nexus. A number of 

commenters also would exclude manmade and man-altered features from the definition of 

tributary because their inclusion would subject water management facilities to full CWA 

jurisdiction. 

The final rule does not distinguish among natural, modified, and constructed features in the 

definition of “tributary.” If a water meets the definition of “tributary” and is not excluded under 

paragraph (b), the water is considered jurisdictional. The rationale for this approach is based on 

the fact that modified and constructed tributaries perform many of the same functions as natural 

tributaries, especially the conveyance of water that carries nutrients, pollutants, and other 

constituents, both good and bad, to traditional navigable waters, interstate waters, and the 

territorial seas. Modified and constructed covered tributaries also provide corridors for 

movement of organisms between headwaters and traditional navigable waters, interstate waters, 

and the territorial seas. The important effect – and thus the significant nexus – between a 

tributary and a traditional navigable water, interstate water, and the territorial sea is not broken 

where the tributary flows through a culvert or other structure. The scientific literature recognizes 

that features that convey water, whether they are natural, modified, or constructed, provide 

substantial connectivity between streams and downstream waters. For example, ditches that 

meet the definition of “tributary” quickly move water downstream to traditional navigable 

waters, interstate waters, and the territorial seas due to their often straightened and channelized 

nature, transporting downstream sediment, nutrients, and other materials.

Note that in order to be considered tributary, under the final rule a stream or ditch must not only 

have the physical characteristics called for under the definition (i.e., bed, banks, and ordinary 

high water mark), the water must also contribute flow to a traditional navigable water, interstate 

water, or territorial sea either directly or indirectly through another water. In addition, 

paragraph (b) of the final rule excludes ditches that do not contribute flow to a traditional 

navigable water, interstate water, or territorial sea. Thus, the final rule is responsive to some 

commenters’ concern that a ditch might be considered a jurisdictional tributary even where not 

hydrologically connected.

While the final rule does exclude several types of constructed waters from jurisdiction, it 

continues to consider constructed tributaries as jurisdictional unless expressly excluded in 

paragraph (b) for the reasons described in summary essays in this Tributary Compendium, the 

final rule preamble, and the Technical Support Document. The agencies also note that current 

practice regulates many modified and constructed features as waters of the United States; see, for 

example, the 2008 Rapanos Guidance discussed earlier.

The issue of ditches as tributary is discussed further in this compendium under “Summary of 

Comments and Responses for “Tributaries – Definition,” which contains comments addressing 

ditches outside the sub-issue of whether wetlands, lakes, and ponds should be considered 

tributary. In addition, another compendium addresses the issue of excluded ditches specifically, 

and responds to concerns similar to those raised by comments excerpted below.
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Specific Comments

Region 10 Tribal Caucus (Doc. #14927)

8.212 The Tribal Caucus supports the broad definition of Waters of the U.S. (“WOTUS”) to 

include:

...all other waters such as intrastate lakes, rivers, streams (including intermittent 

streams), mudflats, sandflats, wetlands, sloughs, prairie potholes, wet meadows, 

playa lakes, or natural ponds, the use, degradation or destruction of which could 

affect interstate or foreign commerce including any such waters: Which are or 

could be used by interstate or foreign travelers for recreational or other purposes; 

from which fish or shellfish are or could be taken and sold in interstate or foreign 

commerce; or which are used or could be used for industrial purposes by 

industries in interstate commerce.

In particular, the Tribal Caucus strongly supports the proposed rule for the clear 

protections it restores to headwaters, intermittent and ephemeral streams, and to wetlands 

and other waters located near or within the floodplain of these tributaries and the [...] (p. 

2)

Agency Response: Under the final rule, an interstate commerce connection is not 

sufficient to meet the definition of “waters of the United States.” The agencies’ 

conclusions in the final rule that certain categories of waters are jurisdictional are 

based on careful examinations of the science and the law that particular categories 

of waters significantly affect the chemical, physical, and biological integrity of a 

traditional navigable water, interstate water, or the territorial seas. In reference to 

headwaters, intermittent and ephemeral streams, the final rule provides that all 

features meeting the definition of “tributary” at paragraph (c) of the rule are waters 

of the United States unless they are specifically excluded in paragraph (b). The 

jurisdictional status of “wetlands and other waters located near or within the 

floodplain of these tributaries” is addressed in the adjacency provisions of the final 

rule, which are described in Section IV(G) of the preamble and section VIII of the 

Technical Support Document.

Pueblo of Sandia (Doc. #2729)

8.213 The Pueblo also supports the definition of tributary and the importance of defining 

ditches as "waters of the US" where they function as tributaries conveying water flows 

and pollutants downstream. Scientific evidence has shown that these waters have an 

important biological, hydrological and chemical connection to downstream waters and 

their protection is paramount. (p. 2)

Agency Response: Under the final rule, ditches that meet the definition of 

“tributary” at paragraph (c) of the rule are waters of the United States unless they 

are specifically excluded in paragraph (b).

8.214 Wetlands store and filter flood flows, protect water quality, provide essential fish and 

wildlife habitat and reduce flood flow that can threaten communities and community 

infrastructure. Wetlands, even so-called isolated wetlands that are not adjacent to streams 
Clean Water Rule Response to Comments – Topic 8: Tributaries

402

provide important biological and hydrological functions and should be protected. The 

Pueblo asks that the final rule recognize these non-adjacent wetlands. (p. 2)

Agency Response: The final rule reflects the agencies careful integration of 

science with policy judgment and legal interpretation to determine which waters 

have a “significant nexus” to traditional navigable waters, interstate waters, or the 

territorial seas. Section IV(G) of the preamble to the final rule and section VIII of 

the Technical Support Document discuss “adjacent waters,” and Section IV(H) of 

the preamble and section IX of the Technical Support Document discuss “casespecific waters of the United States.” 

Missouri Department of Transportation (Doc. #3313)

8.215 3. Comments relating to the inclusion of wetlands under the definition of tributary

Proposed Requirement or Section Addressed: The requirement that we are addressing is 

the intent of the proposal to include wetlands in the tributary definition (as referenced on 

page 22206 of the federal register).

Comment: Again, for the sake of regulatory clarity, MoDOT supports the exclusion 

wetlands from the tributary definition because they generally do not possess a defined 

bed, bank and OHWM.

Recommendation: For the purposes of clarity, capturing jurisdiction of headwater 

wetlands and wetlands in connecting tributaries in the “adjacent” definition (through use 

of the terms neighboring, floodplain, and riparian zone), seems to be a much better way 

to address this issue. (p. 2-3)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries.

Virginia Department of Transportation (Doc. #12756)

8.216 On p. 22263, second column, paragraph (c)(5), Tributaries are defined to include ponds 

that contribute flow directly or indirectly to a WOUS. This definition creates another 

potential point of confusion, as upland ponds could discharge surplus waters either via 

overland flow or through an excavated channel into other tributaries (that are truly 

jurisdictional). This definition, then, appears to exert jurisdiction over those 

impoundments as well and does not clearly exempt them from regulation. We 

recommend that the reference to ponds be stricken throughout this proposed regulation. 

(p. 6)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries. While such features may be waters of the United States 

under other provisions of the final rule, for example as “adjacent” waters, 

paragraph (b) of the final rule includes a number of exclusions under which certain 

ponds would not be considered waters of the United States. Examples of “upland 

ponds” that would not be waters of the United States include artificial lakes and 
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403

ponds created in dry land and used primarily for uses such as stock watering, 

irrigation, settling basins, rice growing, or cooling ponds.

North Carolina Forest Service, North Carolina Department of Agriculture (Doc. #14122)

8.217 COMMENT 3

Change a portion of the proposed definition of the term "tributary" to remove the 

reference to ditches, and clarify the intent of the definition, as we suggest below:

Current Proposed Text We Suggest Replacing:

..... .. A tributary, including wetlands, can be a natural, man altered, or man-made waters 

and includes waters such as rivers, streams, lakes, ponds, impoundments, canals, and 

ditches not excluded in paragraphs (b)(3) or (4) of this section.

Suggested Change:

..... . "A tributary, Impoundments can be regulated

 features which may also include wetlands, is a naturally occurring or humanaltered body of water such as a stream, creek, river, lake. pond, permanent 

impoundment, or commercially navigable canal. For the purposes of this rule, 

ditches shall not be considered to be a tributary."

Justification for Comment 3:

Our contention is that ditches, including those excavated for minor drainage in wetlands 

as allowed under Section 404 (40CFR 232.3), are not appropriate to be considered as 

waters of the U.S. Ditches may or may not be hydrologically-connected to another water 

feature, and therefore cannot always be presumed to influence the biological, chemical, 

or physical quality of nearby or downstream receiving waters; either waters in close 

proximity or waters that are adjacent, to the ditch. Many ditches only collect or transport 

surface water immediately following rainfall events, and therefore do not contribute 

perennial flow. (p. 2-3)

Agency Response: The final rule is consistent with the agencies’ longstanding 

interpretation of the CWA that a tributary can be a natural, man-altered, or manmade water. Waters of the United States, as defined in the final rule, thus include 

waters such as rivers, streams, canals, and ditches not excluded under paragraph 

(b). Ditches are one important example of constructed features that in many 

instances can meet the definition of tributary. Ditches are jurisdictional under the 

final rule only if they both meet the definition of "tributary" and are not excluded 

under paragraph (b) in the rule. Not all ditches meet the definition of a tributary, 

and others are expressly excluded from jurisdiction. Section IV(F) of the preamble 

to the final rule discusses tributaries and section IV(I) discusses “Waters and 

Features that Are Not Waters of the United States.” See also the summary response 

for “Relevance of Flow Regime” in Section 8.1.1 above, particularly the subsection 

on “Regulation of Man-Altered Streams.”
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404

Texas Commission on Environmental Quality (Doc. #14279)

8.218 Defining boundaries and limits for explicit categories of waters of the U. S. [33 CFR 

§328.3(a)(1)-(5)]

The TCEQ requests that wetlands not be defined as part of a tributary system. The 

proposed rule states that wetlands, lakes, and ponds which contribute flow to (a)(i)- (3) 

waters will be considered tributaries 133 CFR §328.3(c)(5)]. However, in the preamble, 

EPA requests comments on whether wetlands should be considered adjacent waters 

rather than tributaries or potentially addressed through other considerations of 

connectivity (pages 22203 and 22208). EPA and the Corps should address wetlands as 

either adjacent waters or other waters depending on the case-specific facts. (p. 6)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries. 

North Dakota Office of the Governor et al. (Doc. #15365)

8.219 8. The proposed rule’s treatment of wetlands is inconsistent and overly broad, 

making virtually all wetlands jurisdictional.

Connectivity of wetlands under federal jurisdiction should be limited to those immediate 

or proximate to major flowing water bodies that are navigable in the traditional sense. 

Extended connections should be exempted.

a. When defined as tributaries with ephemeral flow, the widely varying climactic 

regimes in North Dakota will inevitably make almost all wetlands jurisdictional.

The proposed expansive definition of tributaries includes anything with a bed and banks 

and ordinary high water mark that ever sends any flow, and waters that contribute flow –

either directly or through another water – even if the flow is ephemeral.459 The chain of 

waters included under the tributary definition460 is expanded even further by including 

adjacent waters and including other waters461 by situation. This expansive definition 

means that almost all surface waters will be jurisdictional under various climactic 

scenarios. Under these proposed definitions, few wetlands would be exempt in a realistic 

field setting.

Depending on the year, climactic changes allow wetlands to overtop and connect with

waters that would be tributaries or are completely dry. There are many large prairie 

potholes that in the 1930s were mostly dry and disconnected from any outlet. During the 

half century following the 1930s multi-decadal drought, many wetlands remained 

isolated. Following the wet shift in the 1990s, these wetlands have increasingly coalesced 

 

459 79 Fed. Reg. 22188, 22263.

460 79 Fed. Reg. 22188, 22198 (“All waters, including wetlands, adjacent to a traditional navigable water, interstate 

water, the territorial seas, impoundment, or tributary.”).

461 Id. (“d.1. 79, No. 76/Monday, April 21, 2014/Proposed Rules, impoundment, impoundmenttate water, the 

territorial seas, impoundment including wetlands, located in the same region, have a significant nexus to a traditional 

navigable water, interstate water or the territorial seas”).
Clean Water Rule Response to Comments – Topic 8: Tributaries

405

or connected with other wetlands and to larger water bodies. Which waters are connected 

varies depending on time and the current climate regime.

Under EPA’s proposed rule, recent climatic events would authorize broad federal 

authority over depressional areas that are often isolated from the navigable water or even 

dry, but periodically connected. As above, it would be one thing to regulate a water 

quality component at the point of entry to a clearly navigable water during the time of 

physical connection. To use that temporary connection as a pretense to redefine that 

waterbody itself permanently as WOTUS represents a massive inflation of federal 

jurisdictional claims. (p. 7-8)

Agency Response: See summary response for “Relevance of Flow Regime” in 

section 8.1.1 of this RTC, particularly subsections on jurisdiction over intermittent 

and ephemeral waters and the legality of asserting jurisdiction over ephemeral 

waters. Section I of the Technical Support Document further discusses the legal 

basis of the final rule, including consistency with the statute and Supreme Court 

decisions. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion that all waters that meet the definition of 

“tributary” and that are not excluded in paragraph (b), have a significant nexus 

either individually or in the aggregate with traditional navigable waters, interstate 

waters, and the territorial seas. The final rule reflects the agencies careful 

integration of science with policy judgment and legal interpretation to determine 

which waters, including wetlands, have a “significant nexus” to traditional 

navigable waters, interstate waters, or the territorial seas. Section IV(G) of the 

preamble to the final rule and section VIII of the Technical Support Document 

discuss “adjacent waters,” and Section IV(H) of the preamble and section IX of the 

Technical Support Document discuss “case-specific waters of the United States.”

Ohio Department of Natural Resources et al. (Doc. #15421)

8.220 As proposed, the definition of "tributary" would include water resources "such as rivers, 

streams, lakes, impoundments, canals, and ditches" as well as wetlands when they 

directly or indirectly contribute flow to a water body included in (a)(l) to (a)(3) of the 

proposed rule water that are not otherwise excluded by (b)(1) to (b)(5) of the rule. The 

multitude of reasons for this were provided in the discussions accompanying the 

proposed rule, but the practical reason for including these resources into the term 

"tributary" was to allow the Corps and EPA to more easily take jurisdiction on the waters 

without having to complete a case-specific significant nexus determination.

The USEPA and USACE may feel that the reason to do so may well be justified, but 

there will be additional implications to inclusion of many types of aquatic resources into 

the proposed definition of "tributary." While the definition for "wetlands" was also 

included in the proposed rule, no definitions were added for the other aquatic resource 

types (rivers, streams, lakes, impoundments, canals, and ditches) that would be included 

in the overall encompassing term of "tributary." It is important that these aquatic 

resources also be clearly defined in the rule. If this is not done, it will result in the 

continued confusion of how to regulate these resources, While water resources such as 

rivers, streams, lakes, impoundments, canals, and ditches are all proposed to be included 

under the term "tributary", these resources do not possess the same defining physical 
Clean Water Rule Response to Comments – Topic 8: Tributaries

406

characteristics, they do not provide the same ecological functions and values, and they do 

not have the same influence on the character of a downstream water body. Current 

Nationwide Permit (NWP) conditions (including specific regional conditions) have 

varying applicability criteria based on the type and quantity of water resources impacted. 

Specific mention is made to streams, wetlands, and waterbodies. The types of water 

resources included in the term "tributary" must also be clearly defined so that an 

applicant and regulator can assess what type of aquatic resource Is being impacted, what 

impact calculations may be applicable, what type of waterway permit may be required 

(NWP or individual404j, and what type of aquatic resource mitigation may be 

appropriate. For example, while both a stream and a ditch may be considered a 

"tributary" by the proposed definition, and therefore jurisdictional, would they be 

regulated the same? Would they require the same "tributary" mitigation, even though they 

do not function in the same manner ecologically? The same could be considered for the 

treatment of a stream type "tributary" versus an Impoundment type "tributary", or lake 

type "tributary." The way It is currently addressed in the proposed rule continues, or 

exacerbates, the ambiguity in defining the water resources, and likely would Increase the 

inconsistencies in regulation of the water resources between Corps Districts (and 

Individual regulators within those Districts) nationwide.

The proposed rule revision is the EPA's and the USACFs chance to clarify and define the 

types of water resources that are regulated by the EPA and USACE. These definitions 

could then be referred to and referenced in future regulatory guidance on Identification 

and delineation protocols as well as compensatory mitigation rules. (p. 7-8)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries. The final rule is consistent with the agencies’ 

longstanding interpretation of the CWA that a tributary can be a natural, manaltered, or man-made water. Waters of the United States, as defined in the final 

rule, thus include waters such as rivers, streams, canals, and ditches not excluded 

under paragraph (b). Ditches are one important example of constructed features 

that in many instances can meet the definition of tributary. Ditches are 

jurisdictional under the final rule only if they both meet the definition of 

"tributary" and are not excluded under paragraph (b) in the rule. Not all ditches 

meet the definition of a tributary, and others are expressly excluded from 

jurisdiction. Section IV(F) of the preamble to the final rule discusses tributaries and 

section IV(I) discusses “Waters and Features that Are Not Waters of the United 

States.” See also the summary response for “Relevance of Flow Regime” in Section 

8.1.1 above, particularly the subsection on “Regulation of Man-Altered Streams.” 

Permitting programs under the CWA, including Section 404 permitting, are beyond 

the scope of the final rule.

8.221 1. The agencies request comment on all aspects of the proposed definition of tributaries 

and in particular on whether and how this definition can be revised to provide increased 

clarity as to the distinction between jurisdictional tributaries, as defined, and 

nonjurisdictional features such as gullies, rills and non- wetland swales. The agencies 

seek comments on how to provide greater regulatory certainty as to which specific 

aquatic features are jurisdictional tributaries, and which are not, Commenters should 
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407

explain how any suggestions are consistent with the Clean Water Act, applicable case 

law, and the scientific literature regarding connectivity of aquatic features.

MRM [Division of Mineral Resources Management]: While the proposed rule intent is to 

clearly spell out and provide specific definition for “tributary” that includes 

characterization of a "bed, bank and ordinary high water mark" and provides "flow either 

directly or indirectly to waters in (a)(1) through (4) of the proposed rules, it is unclear and 

somewhat confusing to include wetland, lakes, and ponds as "tributaries" as well. By 

including these other water features into the definition for "tributary", which appears to 

be a substitution for "streams" in the new policy, adds to the confusion. (p. 11)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries.

8.222 3. The agencies recognize that it may add an element of uncertainty to the definition of

tributary to include features as tributaries (wetlands) which do not have a bed and banks 

and OHWM. An alternate approach would be to clarify that wetlands that connect 

tributary segments are adjacent wetlands, and as such are jurisdictional waters of the 

United States under (a)(6). The agencies request comment on this alternate approach, as 

well as any other suggestions commenters may have on how to clarify the definition of

tributaries and provide a clear explanation of their lateral and upstream extent.

MRM: Wetlands should not be included within the definition for "tributary' as they do 

not have defined bed, bank, or ordinary water mark. The proposed alternate approach is 

the preferred.

The jurisdictional nature of tributaries is described somewhat unclearly. A jurisdictional 

8b tributary contributes flow either directly or through another water to (a)(1) through 

(a)(4) waters -- interstate or foreign commerce waters, interstate waters, the territorial 

seas. or impoundments of such wafers. This is a very indirect approach to stating that all

streams to the head waters of first order streams are jurisdictional, which is apparently the 

intent. It would be much clearer to state this fact more directly, rather than requiring an 

inference. Also, it appears, based on the tributary definition, that wetlands, lakes, and 

ponds are not tributaries if (1) they contribute flow to impoundments of (a)(1) through (3) 

and (5) waters and to (a)(7) waters (“other waters"). The basis for this is unclear and 

should be clarified. (p. 16)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries.

Attorney General, State of Michigan (Doc. #16469)

8.223 the proposed definition of "tributary" includes the following language: "wetlands, lakes 

and ponds are tributaries (even if they lack a bed, banks, or ordinary high water mark) if 

they contribute flow [to a core water]." (Emphasis added.) This is contrary to the 

common understanding of a tributary, which is an identifiable water course that connects 

to a larger stream, river, or other water body. This is reflected in Michigan law, which for 

decades has described the streams, lakes, or ponds that may be tributaries to larger bodies 

of water as a "body of water that has definite banks, a bed, and visible evidence of a 
Clean Water Rule Response to Comments – Topic 8: Tributaries

408

continued flow or continued occurrence of water. . ." Part 301 of the NREPA, Mich. 

Comp. Laws § 324.30101(i) (defining "[i]nland lake or stream") (emphasis added). (p. 5)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries.

Tennessee Department of Transportation (Doc. #16470)

8.224 The proposed rule defines tributaries of certain other waters as jurisdictional by rule and 

includes a new definition of "tributary." TDOT agrees with the concept of defining 

certain tributaries as jurisdictional by rule. TDOT also agrees that it is appropriate and 

useful to include a definition of the term "tributary" in the regulations. However, TDOT 

is concerned that the proposed rule would, in effect, substantially broaden the universe of 

tributaries that are deemed jurisdictional by rule. In as much, TDOT recommends 

revising the rule to be more consistent with the treatment of tributaries in the 2008 

Guidance.

...

C. Relationship to exclusions for ditches

The definition of "tributary" in the proposed rule includes "ditches not excluded in 

paragraph (b)(3) or (4) of this section." TDOT interprets this statement to mean that, if a 

ditch is excluded by paragraphs (b)(3) or (b)(4), the ditch cannot be considered 

jurisdictional , even if it would otherwise , to a TNW would not meet the definition of 

"tributary." .

TDOT suggests that the final rule should make clear that the exclusions take precedence 

over the jurisdictional-by-rule provisions. (p. 4, 5)

Agency Response: See summary response for “Relevance of Flow Regime” in 

section 8.1.1 of this RTC, particularly subsections on jurisdiction over intermittent 

and ephemeral waters and the legality of asserting jurisdiction over ephemeral 

waters. Section I of the Technical Support Document further discusses the legal 

basis of the final rule, including consistency with the statute and Supreme Court 

decisions. The agencies’ position in regard to tributaries is rooted in a science-based 

conclusion that such waters have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion. Paragraph (b) of the final rule identifies 

exclusions and makes clear that the features identified therein “are not waters of the 

United States even where they otherwise meet the terms of paragraphs (a)(1) 

through (a)(8)” of the rule.

State of South Dakota (Doc. #16925)

8.225 In an EPA blog post dated July 7, 2014, Nancy Stoner, EPA Acting Assistant 

Administrator for Water, made several claims unsupported by the actual language of the 

rule. In the post, Ms. Stoner stated, "The proposed Waters of the U.S. rule does not 

regulate new types of ditches, does not regulate activities on land, and does not apply to 
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409

groundwater." The rule includes "ephemeral streams," "wetlands," and "seasonal ponds." 

These are areas that are usually dry but where water channels and flows or ponds when it 

rains. By categorically designating them as "waters of the United States," any farming or 

ranching activities which have historically occurred here are now subject to Clean Water 

Act permitting and/or restrictions. Further, by including "ditches" as part of the 

definition, the agencies are clearly exceeding the authority granted under the Clean Water 

Act to regulate "navigable" waters.

Most concerning, Ms. Stoner's blog indicated that, "The proposed rule does not expand 

jurisdiction." The rule includes non-navigable features that do not contain water most of 

the time as a part of the categorical definition of waters of the United States. Under 

current rules, these features meet the definition of waters of the United States only if a 

case-by-case finding that the area has a significant effect on navigable waters. Moving 

from a case-by-case determination to a categorical inclusion is an expansion of the rule. 

(p. 4)

Agency Response: Ephemeral streams, wetlands and seasonal ponds have all been 

subject to consideration as waters of the United States for decades. Section I of the 

Technical Support Document discusses the legal basis of the final rule, including the 

historic scope of the regulatory definition of “waters of the United States. See 

summary response for “Relevance of Flow Regime” in section 8.1.1 of this RTC, 

particularly the subsection on jurisdiction over intermittent and ephemeral waters. 

The final rule excludes most ditches that are not relocated tributaries or excavated 

in a tributary. See the summary response for Section 8.2, particularly the 

subsection on “Ditches as Tributary.” The agencies’ position in regard to 

tributaries is rooted in a science-based conclusion that such waters have a 

significant nexus either individually or in the aggregate with traditional navigable 

waters, interstate waters, and the territorial seas. Section VII of the Technical 

Support Document discusses the science supporting the agencies’ conclusion. 

Paragraph (b) of the final rule also excludes many artificial lakes and ponds, 

detention and retention basins and water filled depressions created in dry land 

incidental to mining or construction activity from being considered waters of the 

United States. All exemptions in the CWA, including those at section 404(f) for 

normal farming, silviculture and ranching activities remain in effect and unchanged 

as a result of the final rule.

State of Alaska (Doc. #19465)

8.226 The inclusion of wetlands, lakes, and ponds in the definition of “tributary” adds 

significant confusion and would create significant implementation problems. Any 

rulemaking should not subject lakes and ponds to the significant nexus test, as that test is 

inapplicable for these types of waters, and is only applicable, if at all, to wetlands. 

Further, ponds and lakes without a surface water connection to downstream navigable 

waters should be categorically excluded from jurisdiction. (p. 26)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries. Section II of the Technical Support Document discusses 

significant nexus analysis. Paragraph (b) of the final rule excludes many artificial 
Clean Water Rule Response to Comments – Topic 8: Tributaries

410

lakes and ponds, detention and retention basins and water filled depressions created 

in dry land incidental to mining or construction activity. 

Skamania County Board of Commissioners, Washington (Doc. #2469.1)

8.227 ...the EPA and the Corps state that the purpose of the rule is to provide clarity in the 

jurisdictional process. However, the definition is unclear. The proposed rule states that 

man-made conveyances, including ditches, are considered jurisdictional tributaries if they 

have a bed, bank and ordinary high water mark (OHWM) and flow directly or indirectly 

into a "water of the U.S.," regardless of perennial, intermittent or ephemeral flow. The 

proposed rule excludes certain types of upland ditches with less than perennial flow or 

those ditches that do not contribute flow to a "water of the U.S." However, key terms 

like "uplands" and "contribute flow" are not defined. It is unclear how currently 

exempt ditches will be distinguished from jurisdictional ditches, especially if they 

are near a "water of the U.S." A public infrastructure ditch system - roadside, flood or 

stormwater - is interconnected and can run for hundreds, if not thousands of miles. 

Ditches are not wholly in uplands nor do they strictly drain in uplands, since they are 

designed to convey overflow waters to an outlet. (p. 3-4)

Agency Response: See the summary response for Section 6.2 in the Ditches 

compendium of this RTC for a discussion of how the exclusions for ditches were 

revised and clarified for the final rule. The final rule is consistent with the agencies’ 

longstanding interpretation of the CWA that a tributary can be a natural, manaltered, or man-made water. Waters of the United States, as defined in the final 

rule, thus include waters such as rivers, streams, canals, and ditches not excluded 

under paragraph (b). Ditches are one important example of constructed features 

that in many instances can meet the definition of tributary. Ditches are 

jurisdictional under the final rule only if they both meet the definition of 

"tributary" and are not excluded under paragraph (b) in the rule. Not all ditches 

meet the definition of a tributary, and others are expressly excluded from 

jurisdiction. Section IV(F) of the preamble to the final rule discusses tributaries and 

section IV(I) discusses “Waters and Features that Are Not Waters of the United

States.” See also the summary response for “Relevance of Flow Regime” in Section 

8.1.1 above, particularly the subsection on “Regulation of Man-Altered Streams.”

Franconia Township, Pennsylvania (Doc. #8661)

8.228 Wetlands should also not be considered "tributaries" in the final rule, as they should have 

to meet "adjacency" or "significant nexus" tests associated with "adjacent" or "other 

waters" to be considered "waters of the U.S." (p. 3)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries.

Murray County Board of Commissioners (Doc. #7528)

8.229 VI. WETLANDS AS TRIBUTARIES
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The proposed rule includes as part of the definition of "tributary" a wetland that 

has a stream inlet and a stream outlet, or just a stream outlet as in the case of a 

wetland headwater.

This proposal is one of the more absurd wordsmithing aspects to the proposed rule. The 

rule's prefatory comments seek comment on whether to include, as part of the definition 

of a "tributary," a wetland that contributes surface water to downstream navigable waters. 

These proposed tributary wetlands may be headwaters of the tributary network or located 

outside of the headwaters within a stream channel itself. 

Wetlands are not understood as tributaries in either common sense, plain language or in 

statutory and caselaw verbage. It is not logical to refer to a wetland, a body of water 

without a defined bed, bank, and ordinary high water mark, as a "tributary."

Wetlands that are connected hydrologically to a stream with perennial flow into 

navigable water certainly meet the hydrological connection test authored by Justice 

Scalia under Rapanos and likely also meet the significant nexus test authored by Justice 

Kennedy.

We are concerned that the proposed rule attempts to define wetlands as jurisdictional 

tributaries if the wetland, when at full retention capacity, overflows across upland during 

a rainfall event, thereby establishing a hydrological connection to a perennially flowing 

tributary. All wetlands, when at full retention capacity within their basin, flow overtop 

upland when additional rainfall occurs. That connection, in and of itself, does not make 

the wetland jurisdictional as a tributary to other tributaries or covered waters. 

The agencies must evaluate the connectivity and nexus of waters and wetlands under 

"normal circumstances." For example, when delineating a wetland, evidence gathered 

under conditions that are too wet or too dry are typically not considered as credible 

indicators for identifying whether the land is classified as "wetland." Similarly, using 

hydrological connections between wetlands during extreme rainfall events and tributaries 

does not create a credible indicator that the wetland has a jurisdictional connection that 

significantly impacts the integrity of navigable waters.

We believe that the agencies' attempt to describe some wetlands as tributaries is an 

attempt to bring more wetlands into jurisdiction as "navigable waters" without proper 

scientific or legal justification. If a wetland's outlet is the justification for a finding of 

"significant nexus" under Justice Kennedy's test in Rapanos, then the wetland is 

jurisdictional as an "adjacent wetland." Claiming jurisdiction over the wetland as a 

tributary only further confuses the regulated community and prevents clear, bright-line 

rules that can be understood in the field.

Furthermore, the agencies inclusion of wetlands as tributaries is contradictory to its

analysis of adjacent wetlands within the proposed rule. Under the agencies analysis of 

adjacent waters, the agencies state, "In circumstances where a particular water body is 

outside of the floodplain and riparian area of a tributary, but is connected by a shallow 

subsurface hydrologic connection or confined surface hydrologic connection with such 

tributary, the agencies will also assess the distance between the water body and tributary 

in determining whether or not the water body is adjacent." In the case of a wetland 

connected by a confined surface hydrologic connection, a reasonable interpretation of the 
Clean Water Rule Response to Comments – Topic 8: Tributaries

412

proposed rule would conclude that all such wetlands would be tributaries due to their 

outlet connection. Therefore, no wetland would be outside of reasonable proximity to 

other waters of the United States as they would all be considered tributaries themselves.

RECOMMENDATION: We recommend that the agencies do not consider wetlands as 

tributaries under the new rule. We support jurisdiction over wetlands that are adjacent to 

navigable waters, interstate waters, or the territorial seas. We support the clarity of a rule 

that defines adjacent as "neighboring" and limits the interpretation of neighboring to only 

those wetlands that have a confined surface hydrologic connection within a reasonable 

proximity to navigable waters. (p. 10-11)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries. The final rule does not define “neighboring” as 

restrictively as recommended by the commenter. Section IV(G) of the preamble to 

the final rule and section VIII of the Technical Support Document discuss 

“Adjacent Waters,” of which, “neighboring” is one component.

City of Chesapeake, Virginia (Doc. #9615)

8.230 The Rule proposes to categorize wetlands, lakes, ponds, impoundments and ditches as 

tributaries, even if they lack a bed and banks or Ordinary High Water Mark (OHWM), if 

they contribute flow to WOUS, regardless of perennial, intermittent or ephemeral flow; 

therefore, by Rule, these features would be jurisdictional WOUS without any significant 

nexus analysis. The City does not support a definition of tributaries to include features 

such as wetlands, lakes, ponds, impoundments or ditches. It would also not be 

appropriate to evaluate these features as adjacent waters, resulting in jurisdictional 

determinations without any significant nexus analysis; however, it may be appropriate to 

evaluate these features through a case-specific significant nexus analysis as "other 

waters." (p. 2)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries. The final rule is consistent with the agencies’ 

longstanding interpretation of the CWA that a tributary can be a natural, manaltered, or man-made water. Waters of the United States, as defined in the final 

rule, thus include waters such as rivers, streams, canals, and ditches not excluded 

under paragraph (b). Ditches are one important example of constructed features 

that in many instances can meet the definition of tributary. Ditches are 

jurisdictional under the final rule only if they both meet the definition of 

"tributary" and are not excluded under paragraph (b) in the rule. Not all ditches 

meet the definition of a tributary, and others are expressly excluded from 

jurisdiction. Section IV(F) of the preamble to the final rule discusses tributaries and 

section IV(I) discusses “Waters and Features that Are Not Waters of the United 

States.” See also the summary response for “Relevance of Flow Regime” in Section 

8.1.1 above, particularly the subsection on “Regulation of Man-Altered Streams.” 

Section IV(G) of the preamble to the final rule and section VIII of the Technical 

Support Document discuss “Adjacent Waters.”
Clean Water Rule Response to Comments – Topic 8: Tributaries

413

County of Henry, Virginia (Doc. #10949)

8.231 The Rule proposes to categorize wetlands, lakes, ponds, impoundments and ditches as 

tributaries, even if they lack a bed and banks or Ordinary High Water Mark (OHWM), if 

they contribute flow to WOUS, regardless of perennial, intermittent or ephemeral flow; 

therefore, by Rule, these features would be jurisdictional WOUS without any significant 

nexus analysis. The County does not support a definition of tributaries to include features 

such as wetlands, lakes, ponds, impoundments or ditches. It would not be appropriate to 

evaluate these features as adjacent waters, resulting in jurisdictional determinations 

without any significant nexus analysis; however, it may be appropriate to evaluate these 

features through a case-specific significant nexus analysis as "other waters". (p. 2)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries. The final rule is consistent with the agencies’ 

longstanding interpretation of the CWA that a tributary can be a natural, manaltered, or man-made water. Waters of the United States, as defined in the final 

rule, thus include waters such as rivers, streams, canals, and ditches not excluded 

under paragraph (b). Ditches are one important example of constructed features 

that in many instances can meet the definition of tributary. Ditches are 

jurisdictional under the final rule only if they both meet the definition of 

"tributary" and are not excluded under paragraph (b) in the rule. Not all ditches 

meet the definition of a tributary, and others are expressly excluded from 

jurisdiction. Section IV(F) of the preamble to the final rule discusses tributaries and 

section IV(I) discusses “Waters and Features that Are Not Waters of the United 

States.” See also the summary response for “Relevance of Flow Regime” in Section 

8.1.1 above, particularly the subsection on “Regulation of Man-Altered Streams.” 

Section IV(G) of the preamble to the final rule and section VIII of the Technical 

Support Document discuss “Adjacent Waters.”

Board of County Commissioners, Otero County, New Mexico (Doc. #14321)

8.232 Specific comment was requested concerning whether in-channel “wetlands” should be 

included with tributaries or adjacent waters. Logically, they seem better positioned in the 

realm of adjacent waters. Placing them in the category of tributaries runs contrary to that 

definition’s requirements for a bed, banks and an ordinary high water mark. (p. 16)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries.

New Mexico Environment Department (Doc. #16552)

8.233 The Department is correspondingly concerned that the proposed rule will also swallow 

non-navigable intrastate waters that are now used for irrigation and drinking water by 

including as "tributary" all "ditches." 79 Fed. Reg. 22,180, 22,203. Currently the 

proposed rule excludes only "upland ditches" ("upland" has not been defined in the 

proposed rule) that drain only upland, and have less than perennial flow. [d. All other 

ditches that connect or are "adjacent" to a jurisdictional water, as will be discussed further 

below, will transform and become, surprisingly, their own federal jurisdictional water. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

414

This will directly impact the many New Mexico communities that rely on acequias and 

other forms of open water ditches, to transport irrigation and pre-potable water. These 

waters are not only life sustaining, but are part of the States' traditional native and 

cultural history. It is probable, because of the proposed rule's ambiguity that acequias will 

fall within the 'per se' jurisdictional sphere. It is unclear on current definitions whether 

adjacent land disturbance or activity, even maintenance of the acequia or ditch, will be 

subject to federal permitting and licensing. The Agencies should have consulted the State 

prior to release of the proposed rule to ensure that such important native and cultural 

rights would be preserved. (p. 14-15)

Agency Response: See the summary response for Section 6.2 in the Ditches 

compendium of this RTC for a discussion of how the exclusions for ditches were 

revised and clarified for the final rule. Ditches are jurisdictional under the final 

rule only if they both meet the definition of "tributary" and are not excluded under 

paragraph (b) in the rule. Not all ditches meet the definition of a tributary, and 

others are expressly excluded from jurisdiction. In addition, all existing statutory 

exemptions, including those at CWA Section 404(f) for maintenance of existing 

irrigation and drainage ditches, remain in effect and unchanged as a result of the 

final rule.

Bureau of Environmental Services, City of Portland, Oregon (Doc. #16662)

8.234 6. BES supports including wetlands in the definition of tributary. But the proposed rule, 

as written, excludes important headwater areas that; depending on the slope of the land, 

volume and/or intermittent flow, do not always have defined beds and banks but are 

equally important to the physical, chemical, and biological integrity of downstream 

waters. While beds and banks always indicate flow, flow is not exclusively defined by 

beds or banks, therefore necessitating a significant nexus analysis for certain types of 

headwater areas. (p. 3)

Agency Response: The agencies revised the definition of “tributary” for the final 

rule in response to the large number of comments from the public comments who 

indicated that including ponds, lakes, and wetlands as tributaries was confusing and 

inconsistent with common understanding. See the summary response for Section 

8.2 above, particularly the subsection on “Wetlands, Lakes and Ponds.” Tributaries 

are also discussed in section IV(F) of the preamble and in section VII of the 

Technical Support Document.

Dolores Water Conservancy District and Southwestern Water Conservation District, Colorado 

(Doc. #19461)

8.235 III. THE DEFINITION OF TRIBUTARY" IS OVERBROAD AND WOULD 

UNLAWFULLY SUBJECT NORMALLY DRY ARROYOS AND IRRIGATION 

DITCHES TO CLEAN WATER ACT JURISDICTION.

In southwestern Colorado, many irrigation ditches divert water from streams which is 

then distributed to fields through a series of lateral ditches. Excess water (i.e., diverted 

but not taken up by plants), which may accrue in ditches either as surface water or as 

seepage (i.e., groundwater) is returned to the stream. Such "return flows" are essential to 

the operation of many ditches to provide sufficient head to drive flow and irrigate fields 
Clean Water Rule Response to Comments – Topic 8: Tributaries

415

and because only so much precision can be achieved due to daily and seasonal variability 

in stream flows and limitations with many irrigation structures. 

Another crucial characteristic of irrigation ditches is that water is typically only diverted 

into them to irrigate intermittently during the growing season. In southwestern Colorado, 

that season typically lasts from mid-April to mid-October. Accordingly, western 

irrigation ditches do not convey water much of the year. As such they do not support 

aquatic habitat typical of either perennial or intermittent streams. 

The definition of "tributary" and "ditches" excluded from jurisdiction in the proposed 

Rule would render almost any irrigation ditch with return flows a "water of the U.S." 

even if return flows accrue far from a significant tributary or have a de minimus impact 

on flows or water quality of the receiving "water." As Reclamation pointed out in 2008, 

which is equally applicable to this Rule:

... this could be the basis for asserting broad jurisdiction over irrigation ditches far 

removed from any navigable body of water because they are "indirectly" 

connected to a navigable water by other tributaries. The guidance states that "a 

tributary includes natural, man-altered, or man-made water bodies that carry flow 

directly or indirectly into a traditional navigable water," with no further 

distinction between man-made and natural water bodies. Reclamation believes 

that jurisdiction over man-made water delivery facilities should be limited.... 

Again, this is an overly broad basis for asserting jurisdiction and could include 

miles of irrigation ditches far removed from waters of the U.S. based on the 

characteristics of the irrigation ditches at the point where it empties into a water of 

the U.S.462

Any final Rule must acknowledge the dynamics of western irrigation practices and 

infrastructure. If the Agencies persist in sweeping such ditches into the jurisdictional net 

of the Clean Water Act, the Agencies must provide an intelligible rationale for doing so 

that comports with the intent of Congress expressed in the Clean Water Act and of

Supreme Court jurisprudence regarding the same. (p. 6-7)

Agency Response: See the summary response for Sections 6.1 and 6.2 in the 

Ditches compendium of this RTC for a discussion of flow in relation to ditches and 

how the exclusions for ditches were revised and clarified for the final rule, 

respectively. Section I of the Technical Support Document discusses the legal basis 

of the final rule, including consistency with the statute and Supreme Court 

decisions. The final rule is consistent with the agencies’ longstanding interpretation 

of the CWA that a tributary can be a natural, man-altered, or man-made water. 

Waters of the United States, as defined in the final rule, thus include waters such as 

rivers, streams, canals, and ditches not excluded under paragraph (b). Ditches are 

one important example of constructed features that in many instances can meet the 

definition of tributary. Ditches are jurisdictional under the final rule only if they 

both meet the definition of "tributary" and are not excluded under paragraph (b) in 

 

462 BOR 2008 Guidance Comments, at p. 2 (emphasis added).
Clean Water Rule Response to Comments – Topic 8: Tributaries

416

the rule. Not all ditches meet the definition of a tributary, and others are expressly 

excluded from jurisdiction. 

North Dakota Water Resource Districts Association (Doc. #5596)

8.236 Also of concern is the application of "tributary" status to wetlands outside the channel of 

a tributary, but are contributing flow to the channel. While using Ordinary High Water 

Mark (OHWM) as a determining factor in establishing jurisdictional tributaries, the 

agencies acknowledge that at there are places along a tributary where the OHWM may 

disappear, such as in a wetland. Under the proposed rule, the agencies would still extend 

Federal jurisdiction to these areas, if not as tributaries, then as "adjacent waters." 

Therefore, when there is a question as to the applicability of the CWACW A to a 

wetland, the rule favors Federal jurisdiction. The agencies request specific comment on 

how to best provide certainty on wetlands where no OHWM is evident and the 

Association feels declining jurisdiction over such wetlands would provide best certainty 

to the regulated community. (p. 1-2)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries. However, the final rule is clear that a water that 

otherwise meets the definition of a tributary does not lose its status as a tributary if, 

for any length, there are one or more constructed breaks (such as bridges, culverts, 

pipes, or dams), or one or more natural breaks (such as wetlands along the run of a 

stream, debris piles, boulder fields, or a stream that flows underground) so long as a 

bed and banks and an ordinary high water mark can be identified upstream of the 

break. This component of the definition did not change from the proposed rule.

Tributaries are further discussed in section IV(F) of the preamble and in section VII 

of the Technical Support Document.

Nebraska Association of Resources Districts (Doc. #11855)

8.237 Under the Proposed Rule, a “tributary” is categorically jurisdictional, and includes 

wetlands, lakes, ponds, impoundments, canals, and ditches, whether natural, man-altered, 

or man-made, if they contribute flow either directly or through another water to an 

interstate water, interstate wetlands, or territorial sea.463 No meaningful exemption from 

this definition is provided,464 and no case-by-case determination as to the status of the 

water will be made. Under the plain language of the Proposed Rule, this means any 

hydrologic connection to a traditionally navigable water, interstate water, or interstate 

wetland, will result in the characterization of an isolated intrastate body or conveyance of 

water as a “tributary.” (p. 6)

Agency Response: See the summary response for Sections 8.1 and 8.2. In 

addition, see the summary response for Section 6.2 in the Ditches compendium of 

 

463 40 CFR 230.3(u)(5) (emphasis supplied).

464 Id. Exempt from the definition of “tributary” are ditches that “drain only uplands” and “do not contribute flow 

either directly or through another water” to any TNW, interstate water, interstate wetland, or territorial sea.
Clean Water Rule Response to Comments – Topic 8: Tributaries

417

this RTC for a discussion of how the exclusions for ditches were revised and 

clarified for the final rule.

8.238 Prior attempts to assert jurisdiction over isolated intrastate bodies or conveyances of 

water, whether through broad definitions of statutory terms or through identifying 

isolated waters as habitat for migratory birds, have been rejected as an overreach of the 

authority granted by the Clean Water Act.465 The Proposed Rule is yet another attempt to 

expand federal jurisdiction over conceivably all waters through exactly the same means. 

(p. 6-7)

Agency Response: Section I of the Technical Support Document discusses the 

legal basis of the final rule, including consistency with the statute and Supreme 

Court decisions and the historic scope of the regulatory definition “waters of the 

United States.”

California Association of Sanitation Agencies (Doc. #12832)

8.239 For the first time, the proposed rule seeks to define what constitutes a “tributary” under 

the Clean Water Act. The proposed rule drastically expands the number of waters 

potentially subject to federal jurisdiction... Perhaps most significantly, under the 

proposed rule, a tributary, including wetlands, can be a natural, man-altered, or manmade water and includes waters such as rivers, streams, lakes, ponds, impoundments, 

canals, and ditches not otherwise explicitly excluded. (Id. at 22202).

This overly broad definition of tributary could potentially increase the number of 

manmade conveyances, ditches and conveyance facilities, including those utilized by 

wastewater entities, under federal jurisdiction, and the lack of certainty surrounding the 

rule’s definition of a tributary could lead to regulation of previously unregulated waters. 

This broad classification of “tributaries” would be considered jurisdictional regardless of 

perennial, intermittent or ephemeral flow. Even dry washes could be considered 

jurisdictional under the proposed rule. This is significant for a variety of reasons.

One example of the potential impacts of defining what constitutes a “tributary” too 

broadly is the potential discharge from sanitary sewer systems to dry 

creeks/sloughs/washes when no pollutants ever actually reach water. It is entirely unclear 

whether this constitutes a discharge of pollutants to a water of the U.S. Under the broad 

definition of tributary in the proposed rule, it is possible that spills to dry creeks, sloughs, 

or washes would be considered a “discharge” even if there is absolutely no real or 

potential impacts to surface waters of any kind.

Similarly, there are circumstances where sewer spills occur in a street that drains to a 

roadside ditch or local creek bed that has no flow and is unconnected to a water of the 

U.S. The responsible party may fully remediate the spill and address all real and potential 

water quality impacts before the spill ever reaches a water source. It is difficult to 

 

465 SWANCC. v. U.S. Army Corps of Engineers, 531 U.S. 159, 166-67, 121 S. Ct. 675, 680 (2001), (The Agencies

have interpreted the CWA “to cover the abandoned gravel pit at issue here because it is used as habitat for migratory 

birds. We conclude that the ‘Migratory Bird Rule’ is not fairly supported by the CWA.” See also United States v.

Riverside Bayview Homes, Inc., 474 U.S. 121, 133, 106 S.Ct. 455 (1985) (the concept of adjacency is defined as 

wetlands that actually abutted on a navigable waterway).
Clean Water Rule Response to Comments – Topic 8: Tributaries

418

understand how can this kind of circumstance could be envisioned as a discharge to 

“waters of the United States” when there is no actual water in a dry creek or ditch nor an 

adverse impact to the environment. (p. 5-6)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries. The final rule is consistent with the agencies’ 

longstanding interpretation of the CWA that a tributary can be a natural, manaltered, or man-made water. Waters of the United States, as defined in the final 

rule, thus include waters such as rivers, streams, canals, and ditches not excluded 

under paragraph (b). Ditches are one important example of constructed features 

that in many instances can meet the definition of tributary. Ditches are 

jurisdictional under the final rule only if they both meet the definition of 

"tributary" and are not excluded under paragraph (b) in the rule. Not all ditches 

meet the definition of a tributary, and others are expressly excluded from 

jurisdiction, including those that are part of a waste treatment system designed meet 

the requirements of the CWA. Tributaries are further discussed in section IV(F) of 

the preamble and in section VII of the Technical Support Document.

Association of California Water Agencies (Doc. #12978)

8.240 Ordinary High Water Mark Delineations Unnecessarily Broad

...wetlands, lakes and ponds would be tributaries (even if they lack a bed and banks or 

OHWM) if they contribute flow, either directly or through another water to a water 

identified in the paragraphs mentioned above. This definition does not address the 

implications for jurisdictional scope inherent in the methodology used in identification of 

the OHWM in practice. Currently, in the arid west, the methodology to be used to locate 

and identify the OHWM is described in the 2008 Lichvar Field Manual.466 (It should be 

noted that the methodology in the 2008 Lichvar Field Manual differs from the 

methodology prescribed in the 2005 Regulatory Guidance Letter 0505.) (p. 11-12)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries. 

Western Coalition of Arid States (Doc. #14407)

8.241 4. Diversion Ditches Become Tributaries

WESTCAS members routinely have to construct conveyances to divert upstream

ephemeral flows around water, solid waste, industrial and power transmission facilities. 

The diversion of upstream flows is not only a good engineering practice, it is also 

required under federal and state stormwater regulations to prevent flows from coming 

into contact with unstable soils during construction activities and potential solid waste 

and industrial activities. For example, Arizona’s Stormwater Construction General 

 

466 The proposed rule mentions the use of the 2008 Lichvar Field Manual on pages 22259 and 22260 of the Federal

Register notice.
Clean Water Rule Response to Comments – Topic 8: Tributaries

419

Permits (CGP) require the use of certain types of control measures to prevent stormwater 

from flowing onto disturbed areas and transporting pollutants off-site.

One common measure used to meet this requirement is the construction of up gradient 

interceptor ditches or channels. When constructed properly, these control measures 

intercept up gradient flows, channel the water around the disturbed project site, and 

discharge the intercepted flows downstream of the project. Often-times these temporary 

control measures become permanent stormwater management features and are included 

in the final design of the project.

However, under the proposed rule these ditches will retain their status as jurisdictional 

waters and any activities undertaken to maintain their function or integrity, i.e., applying 

pesticides to control vegetation or remove sediment that would impede flow, will be 

subject to the same §402 or §404 permitting requirements as stormwater retention and 

groundwater recharge basins. Furthermore, the desire to categorically designate manmade 

ditches as jurisdictional waters is inconsistent with proscriptive state stormwater 

permitting requirements that encourage the use of man-made channels to divert upstream 

flows. In particular, Arizona’s CGP requires site operators to, “...divert run-on flows, or 

otherwise provide other appropriate control measures to account for off-site contributions 

of stormwater and non-stormwater flow.”467 (p. 10-11)

Agency Response: The final rule is consistent with the agencies’ longstanding 

interpretation of the CWA that a tributary can be a natural, man-altered, or manmade water. Waters of the United States, as defined in the final rule, thus include 

waters such as rivers, streams, canals, and ditches not excluded under paragraph 

(b). Ditches are one important example of constructed features that in many 

instances can meet the definition of tributary. Ditches are jurisdictional under the 

final rule only if they both meet the definition of "tributary" and are not excluded 

under paragraph (b) in the rule. Not all ditches meet the definition of a tributary, 

and others are expressly excluded from jurisdiction, including those that are 

stormwater control features constructed to convey, treat or store stormwater that 

are created in dry land. However, this exclusion does not change the agencies’ 

longstanding practice of viewing some waters, such as channelized streams or piped 

streams, as jurisdictional even where used as part of stormwater management 

systems. Thus, stormwater control features that have been built in or excavated 

from jurisdictional waters continue to be jurisdictional waters of the United States. 

Section IV(I) of the preamble to the final rule and the summary responses in 

Compendium 7 of this RTC, “Features and Waters Not Jurisdictional,” provide a 

broad discussion of the final rule’s exclusions. See summary response for section 

6.2, “Excluded Ditches” in this RTC for a more focused discussion of revised and 

clarified ditch exclusions. Tributaries are further discussed in section IV(F) of the 

preamble and in section VII of the Technical Support Document.

8.242 8. Agricultural Ditches meet the Definition of Tributary

 

467 See AZG2013-001. Part 3.1.1.1.1. Run-on Management
Clean Water Rule Response to Comments – Topic 8: Tributaries

420

WESTCAS members operate and maintain thousands of miles of water transmission 

canals, distribution laterals, and drainage ditches, (i.e., “ditches”) throughout the arid 

West. These ditches are used to transport and distribute water for agricultural, industrial, 

and municipal uses. When combined, many of our members ditch systems are also larger 

than most river systems in the United States. In addition, there are hundreds of private 

irrigation and federal reclamation projects in the arid West that provide drinking water to 

over 31 million people, irrigation water to more than 140,000 farmers, and irrigate over10 

million acres of farmland. These lands produce 60% of the nation’s vegetables and25% 

of its fruits and nuts.

Under the proposed rule, man-made conveyances, including ditch systems, meet the 

definition of an (a)(5) water if they have a bed, a bank, and an ordinary high water 

mark(OHWM), and contribute flow either directly or indirectly to a (a)(1) through 

(a)(4)water. Almost every ditch system in the arid West can meet this definition. Most 

transmission and distribution ditches meet the physical description of having a bed, bank 

and OHWM, and usually discharge a small percentage of their water as “carriage” water 

at the end of their system. This is needed to ensure there is adequate head pressure in the 

ditch to deliver water at various turnout gates. When the carriage water is discharged, it is 

typically delivered to the next irrigation operator, or to a TNW. (p. 14)

Agency Response: See summary responses in Section 6.0 and 6.2 of the Ditches 

compendium in this RTC.

Rhode Island Rivers Council (Doc. #16367)

8.243 In regards to whether headwater wetlands should be classified as “tributaries,” or rather, 

as “adjacent wetlands,” it is advised that such wetlands should be defined as adjacent, and 

thus still having a significant nexus to waters of the U.S. by virtue of being connected 

with tributaries. The term tributary by many is considered to mean moving water and 

could create confusion for the regulated communities. By keeping headwater wetlands 

and other similar waterbodies classified as “adjacent,” with established standards for 

showing a significant nexus to another water of the U.S., it is likely more easily explained 

to and understood by the regulated public. (p. 2)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries. 

Washington State Water Resources Association (Doc. #16543)

8.244 Despite the proposals stated objective to add clarity to the regulatory process, the 

proposal in fact creates great confusion and uncertainty. Some of the unanswered 

questions have been alluded to above, e.g., what will be the effect of the proposal on the 

construction and operation of stormwater control facilities, or the repair and replacement 

of ditches. Other issues that must be addressed, through clarification and in the context of 

an ongoing dialogue amongst stakeholders, include:

...

 If an exempt ditch eventually takes on wetland characteristics due to the running 

of water through it, does it become jurisdictional; 
Clean Water Rule Response to Comments – Topic 8: Tributaries

421

...

 Would all ponds or lagoons, including artificial ones that overflow during heavy 

precipitation events, resulting in overland flow that reaches TNWs, become 

jurisdictional? (p. 17, 18, 19)

Agency Response: An exempt ditch that eventually takes on wetland 

characteristics due to the running of water through it will not become jurisdictional. 

See paragraph (b) of the final rule and the summary responses in Section 6.0 and 6.2 

of the Ditches compendium in this RTC. Paragraph (b) of the final rule also 

excludes many artificial lakes and ponds, detention and retention basins and water 

filled depressions created in dry land incidental to mining or construction activity 

from being considered waters of the United States. 

Michigan Association of Conservation Districts (Doc. #16583)

8.245 Additional Concerns with the Proposed Rule:

 Ditches. While the proposal specifically excludes two types of ditches from 

jurisdiction, EPA clarifies the following ditches as jurisdictional waters: natural 

streams that have been altered (e.g., channelized, straightened or relocated); 

ditches that have been excavated in "waters of the United States," including 

jurisdictional wetlands; ditches that have perennial flow; and ditches that connect 

two or more "waters of the United States." The determination of jurisdiction over 

these is made independent of the intended use of those features, which is a cause 

for concern. For example, a constructed pond or wetland intended for reuse or to 

provide water quality improvements could still be jurisdictional under this rule. 

(p. 2)

Agency Response: See summary response in Section 6.2 of the Ditches 

compendium for a discussion of how the proposed exclusions for ditches were edited 

and clarified for the final rule. The final rule is consistent with the agencies’ 

longstanding interpretation of the CWA that a tributary can be a natural, manaltered, or man-made water. Waters of the United States, as defined in the final 

rule, thus include waters such as rivers, streams, canals, and ditches not excluded 

under paragraph (b). Ditches are one important example of constructed features 

that in many instances can meet the definition of tributary. Ditches are 

jurisdictional under the final rule only if they both meet the definition of 

"tributary" and are not excluded under paragraph (b) in the rule. Not all ditches 

meet the definition of a tributary, and others are expressly excluded from 

jurisdiction. In addition to certain ditches, paragraph (b) also excludes many other 

features from being considered waters of the United States. Section IV(I) of the 

preamble to the final rule and the summary responses in Compendium 7 of this 

RTC, “Features and Waters Not Jurisdictional,” provide a broad discussion of the 

final rule’s exclusions. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

422

Federal Water Quality Coalition (Doc. #15822.1)

8.246 ...one SAB Panel member, Dr. Jossleyn, points out that, as currently drafted, the Draft

Connectivity Report does not support including manmade features in the waters of the 

U.S.:

The tributary definition in the Proposed Rule also includes other features such as flood 

control channels, some ditches, underground stormwater drainage works that are not part 

of, nor discussed in, the Draft Science Report. Presumably such man-made features may 

alter the functions associated with the tributary or alter the water quality considerably—

either beneficially (sediment deposition in reservoirs) or adversely (addition of urban 

storm water). The Draft Science Report focused on research from natural systems and 

therefore does not provide sufficient information on which to discuss the role of these 

man-made features. The Panel recommended that more information be provided in the 

Science Report on the effect of man-made features on connectivity—either elimination or

enhancement of connectivity. In urban environments where water flows are largely in 

man-made structures, this information will be necessary to support the conclusion that 

impacts to upstream features not part of the urban infrastructure would have a significant 

impact on navigable waters, when in fact the urban infrastructure itself is the cause of the 

impact to water quality.468 (p. 53)

Agency Response: The definition of “tributary” has been clarified in the final 

rule. The final rule is consistent with the agencies’ longstanding interpretation of 

the CWA that a tributary can be a natural, man-altered, or man-made water. 

Section IV(F) of the preamble to the final rule and section VII of the Technical 

Support Document discusses tributaries, including man-made or man-altered 

tributaries. See also the summary response for “Relevance of Flow Regime” in 

Section 8.1.1 above, particularly the subsection on “Regulation of Man-Altered 

Streams.” Waters of the United States, as defined in the final rule, thus include 

waters such as rivers, streams, canals, and ditches not excluded under paragraph 

(b). Ditches are one important example of constructed features that in many 

instances can meet the definition of tributary. Ditches are jurisdictional under the 

final rule only if they both meet the definition of "tributary" and are not excluded 

under paragraph (b) in the rule. Not all ditches meet the definition of a tributary, 

and others are expressly excluded from jurisdiction. In addition to certain ditches, 

paragraph (b) also excludes many other features from being considered waters of 

the United States. Section IV(I) of the preamble to the final rule and the summary 

responses in Compendium 7 of this RTC, “Features and Waters Not Jurisdictional,” 

provide a broad discussion of the final rule’s exclusions. See summary response for 

section 6.2, “Excluded Ditches” in this RTC for a more focused discussion of revised 

and clarified ditch exclusions. 

Water Advocacy Coalition (Doc. #17921.1)

8.247 ...the proposed rule’s treatment of wetlands, lakes, and ponds as tributaries (even if they 

lack bed, bank, and OHWM) expands the concept of tributary to essentially any type of 

 

468 Id. at 43.
Clean Water Rule Response to Comments – Topic 8: Tributaries

423

water. The common understanding of a tributary is that it is a stream that feeds into a 

larger stream or river. Few would consider a pond, lake, or wetland to be a tributary in 

common parlance. Many members of the SAB Panel raised this issue in their review of 

the proposed rule.469 The agencies provide no support for treating non-stream waters, 

such as wetlands, lakes, and ponds, as tributaries. By including them in the (a)(5) 

tributary definition, the proposed rule allows for jurisdiction over “adjacent waters” in the 

same floodplain or riparian area or that have a subsurface connection with these wetlands, 

lakes, and ponds. Again, this stretches the “tributary” definition too far. (p. 46)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries.

8.248 2. The tributary definition does not provide clarity, but creates confusion.

In addition to its broad reach, the tributary definition is problematic because it relies on 

vague language and confusing concepts, including the following:

...

 Non-stream features as tributaries: Inclusion of wetlands, lakes, and ponds as 

tributaries, even when they do not have a bed, bank, and OHWM, makes the 

“tributary” definition confusing and conflicts with the way in which tributaries are 

traditionally defined in scientific literature.470 For example, under the proposed 

rule, “waters, including wetlands, that are adjacent to a wetland that meets the 

definition of tributary would be considered adjacent waters.” 79 Fed. Reg. at 

22,209. This collapses and confuses the “adjacent wetlands” and “tributary” 

categories of jurisdiction.

 Impoundments as tributaries: The proposed rule’s inclusion of “impoundments” 

as tributaries is confusing, given that the proposed rule identifies impoundments 

as their own separate category of “waters of the United States” such that 

tributaries to impoundments are jurisdictional. When is an impoundment 

regulated under (a)(4)? When is it regulated under (a)(5)? 

... (p. 47, 48-49)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries.

Virginia Manufacturers Association (Doc. #18821)

8.249 ...the Proposal includes what is described as "clarifying" language relating to 

impoundments that raises additional concerns about an expansion of federal jurisdiction 

to impoundments. For example, the Agencies included statements that impoundments can 

become jurisdictional, and that "an impoundment does not cutoff a connection between 

 

469 See id. at 108 (comments of Dr. Amanda Rodewald). [SAB Panel Member Comments, Exhibit 7 at 42 (comments 

of Dr. Michael Josselyn).]

470 See Rodewald Memo, Exhibit 7 at 2.
Clean Water Rule Response to Comments – Topic 8: Tributaries

424

upstream tributaries and a downstream water so tributaries about the impoundment are 

still considered tributaries even where the flow of water is impeded due to the 

impoundment." VMA respectfully submits that purpose-built operational impoundments, 

like those that are common at industrial sites, must be explicitly exempted from 

jurisdiction. (p. 3)

Agency Response: Impoundments of jurisdictional waters of the United States 

have been regulated themselves as waters of the United States under longstanding 

agency practice for decades. Certain impoundments, such as those associated with 

waste treatment systems designed to meet the requirements of the CWA and 

artificial lakes and ponds created in dry land and used primarily for uses such as 

stock watering, irrigation, settling basins, rice growing or cooling ponds, are 

specifically excluded under paragraph (b) of the final rule. Section IV(I) of the 

preamble to the final rule describes the exclusions.

Action United et al. (Doc. #18859)

8.250 ...we support the Agencies' definition of tributary and strongly agree that ditches should 

be defined as "waters of the U.S." where they function as tributaries. There is sufficient 

scientific evidence that some ditches function as tributaries moving water and pollutants 

downstream. In those cases protection is important. (p. 2)

Agency Response: While paragraph (b) of the final rule excludes certain ditches 

from being waters of the United States, non-excluded ditches are jurisdictional 

under the final rule if they meet the definition of "tributary." 

Minnkota Power Cooperative, Inc. (Doc. #19607)

8.251 A wider variety of wetlands and even man-made features are now included within this 

proposed definition of tributaries. We have seen borrow pits from substation construction 

in the past that have since been included in the National Wetland Inventory (NWI) which 

would likely be considered a tributary, and thus by significant nexus, a WOTUS. This 

Proposed Rule would result in numerous additional facilities and construction projects, 

including small projects to now be regulated. The resultant burden of time and resources 

on behalf of the regulated community would be substantial for a very minimal or nonexistent environmental benefit. The economic impact would add to ever increasing costs 

to the regulated community as well as the average citizen. Man-made features should not 

be considered in determinations of a significant nexus unless they have uncontrolled 

perennial flow. (p. 2)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries.

Kerr Environmental Services Corp. (Doc. #7937.1)

8.252 The following two portions of the definition should be deleted as explained below:

"In addition, wetlands, lakes and ponds are tributaries (even if they lack bed and 

banks or ordinary high water mark) if they contribute flow, either directly or 

through another water. ..of this section"
Clean Water Rule Response to Comments – Topic 8: Tributaries

425

"A tributary, including wetlands, can be a natural, man-altered, or man-made 

water and includes waters such as rivers, streams, lakes, ponds impoundments, 

canals and ditches not excluded in paragraph .. . of this section"

These modifications are overly broad, unclear, introduce enormous vagaries, are 

unnecessary, and move these water bodies from the category of "other waters" which 

they have been regulated under since 1986 (33 CFR 328.3(a)(3). This proposed revision 

is unnecessary and the previous definition of "other waters" including intrastate lakes, 

and wetlands was sufficient and avoided the complications being introduced. The 

proposed sentences above are not required by any recent federal court action and are 

therefore beyond the needs of the proposed rulemaking. (p. 6)

These statements are in direct conflict with the exemption for ditches that have less than 

perennial flow. Ephemeral and intermittent ditches are not jurisdictional, or tributaries to 

Waters of the United States and thus should continue to not be regulated as has been the 

case since 1986. All ditches are by definition at least ephemeral as they convey water 

when it is raining. Many ditches in the Coastal Plain are intermittent, in that they 

intercept the seasonal high water table, and can be in part why they were designed and 

constructed. Such conveyances have never been regulated. The only ditches regulated to 

date have been channelized natural tributaries, or those ditches with perennial flow as 

demonstrated by the presence of bed and bank and other characteristics of the “Ordinary 

High Water Mark” (33 CFR 328.3(e). In that manner the conveyance is demonstrating 

that it is in fact a “water” and part of the aquatic system regulated via interstate 

commerce under the CWA. (p. 6)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries. However, the final rule is consistent with the agencies’ 

longstanding interpretation of the CWA that a tributary can be a natural, manaltered, or man-made water. Section IV(F) of the preamble to the final rule and 

section VII of the Technical Support Document discusses tributaries, including 

man-made or man-altered tributaries. See also the summary response for 

“Relevance of Flow Regime” in Section 8.1.1 above, particularly the subsection on

“Regulation of Man-Altered Streams.” Waters of the United States, as defined in 

the final rule, thus include waters such as rivers, streams, canals, and ditches not 

excluded under paragraph (b).

8.253 Intrastate Lakes

Intrastate Lakes do not need to be considered tributaries. If they are at the upstream 

termini of a river or stream (tributary), they should be considered an Adjacent Water. 

Adjacent Waters are being considered by the USEPA and USACE to be waters of the US 

"by rule", and as such only confusion will be lost by moving intrastate Lakes to this 

category.

Wetland

Wetlands should not be included in the definition of tributaries. Wetlands are 

jurisdictionally, either "adjacent", "other waters" or "isolated". Wetlands with no bed and 

bank do not have sufficient flow to be considered to be a tributary, which has heretofore 
Clean Water Rule Response to Comments – Topic 8: Tributaries

426

always required bed and bank and/or ordinary high water mark indicators. The problems 

created by the proposal to include wetlands as tributaries, is as follows:

1. Tributaries by rule are jurisdictional, so consequently any wetland identified is by 

definition jurisdictional. This is factually incorrect, especially in the case of isolated 

wetlands, and creates enormous regulatory over-reach without direction from 

Congress or the federal courts. 

2. Jurisdictional wetlands, since the 1986 regulation, have been considered "other 

waters" (33 CFR 328.3(a)(3), or adjacent wetlands (33 CFR 328.3(a)(7). Those 

wetlands that were not adjacent, pursuant to the Rapanos ruling require a significant 

nexus evaluation (Jurisdictional Determination Form Instructional Guidebook, Q&A 

#21).

a. The proposed regulations would wrongly reclassify wetlands which have been 

considered heretofore as "other waters" and were ruled by the Supreme Court to 

require a significant nexus, to now be determined as "tributaries" that the 

USEPNUSACE consider "by rule" to be jurisdictional. We do not believe a 

regulation can usurp the Supreme Court decision in Rapanos by removing the 

requirement for a significant nexus determination for certain wetlands. (p. 8)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries. 

Portland Cement Association (Doc. #13271)

8.254 v. Adjacent waters should not be considered “tributaries”

... the proposed rule identifies as tributaries features with a bed and bank and ordinary

high water mark. In addition, under the proposal,

wetlands, lakes, and ponds are tributaries (even if they lack a bed and banks or 

ordinary high water mark) if they contribute flow, either directly or through 

another water to a water identified in paragraphs (l)(1)(i) through (iii) of this 

section.

This portion of the proposed definition has its own separate problems and should not be 

adopted by the Agencies.

...2. The proposed definition would unreasonably expand federal jurisdiction

In addition to contradicting current regulations and caselaw on the question of whether 

wetlands adjacent to other adjacent wetlands are in actuality adjacent to flowing waters of 

the US, the rule improperly expands the “adjacency” factor to cover non-wetland waters. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

427

The proposed rule would allow adjacent non-wetland waters to be considered tributaries 

for the first time.471

As with many of the other portions of the proposed rule, this portion of the 

proposed definition would expand federal jurisdiction beyond the scope of the 

Act. Focusing as it does on “navigable waters,” the CWA does not allow for the 

application of federal jurisdiction to “adjacent” non-wetland waters.

3. The contribution of flow is an insufficient rationale for claiming 

tributary status.

The rule would identify wetlands and other waters as tributaries if they contribute flow to 

a tributary. By the Agencies’ own rationale, this is an insufficient link.

The purpose of this portion of the rule is to identify waters that have a significant nexus 

to downstream jurisdictional waters.472 As proposed, the rule establishes a test for proof 

of “adjacency”: a showing that the water be bordering or contiguous to the tributary or be 

in its floodplain or riparian area. These are therefore the only waters that always have a

significant nexus to downstream traditionally navigable waters. Nevertheless, the 

proposal would include another set of waters as always having a significant nexus –

wetlands, ponds and lakes that “contribute flow” to tributaries. Since, under the 

Agencies’ formulation, the contribution of flow in and of itself would be insufficient to 

identify an adjacent water as one always having a significant nexus, an adjacent tributary 

cannot always have a significant nexus simply by contributing flow – doing so would 

make the definitions of “floodplain” and “riparian area” irrelevant.

Further, the rule does not state what factors are to be examined in determining if a water 

“contributes flow.” Such contribution must not include subsurface flow, as it is beyond 

the scope of the CWA. Nor should simply cross-upland stormwater flow be sufficient to 

make an adjacent wetland, lake or pond jurisdictional – all water flows downhill and 

sheetflow is not a proper basis for jurisdiction, as described below. (p. 22-23)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries. Although revised, the definition of “tributary” retains 

the requirement that a water contribute flow, either directly or through another 

water (including an impoundment identified in paragraph (a)(4) of the final rule), to 

a water identified in paragraphs (a)(1) through (3) of the final rule and also possess 

 

471 Indeed, to date, the adjacency discussion has related to wetlands, not other waters. See, e.g., San Francisco 

Baykeeper v. Cargill Salt Div., 481 F. 3d 700, 707 (9th Cir. 2007) (“Rapanos, like Riverside Bayview, concerned 

the scope of the Corps' authority to regulate adjacent wetlands. Justice Kennedy's controlling concurrence explained 

that only wetlands with a significant nexus to a navigable-in-fact waterway are covered by the Act. Id. at 2248 

(Kennedy, J., concurring) ("Consistent with SWANCC and Riverside Bayview and with the need to give the term 

`navigable' some meaning, the Corps' jurisdiction over wetlands depends upon the existence of a significant nexus 

between the wetlands in question and navigable waters in the traditional sense."). No Justice, even in dictum, 

addressed the question whether all waterbodies with a significant nexus to navigable waters are covered by the 

Act.”)

472 As noted above, the entirety of the “always significant” waters portion of the test is based on their significant 

nexus to downstream waters. This obviously includes adjacent waters and wetlands.
Clean Water Rule Response to Comments – Topic 8: Tributaries

428

physical indicators of a bed and banks and an ordinary high water mark in order to 

be considered a water of the United States as a “tributary.”

8.255 vi. Even if included in the rule, lakes and ponds must be defined, and defined as perennial 

waters

Even if the Agencies promulgate a rule identifying wetlands, lakes, and ponds as 

tributaries, they must define lakes and ponds. Such a definition is particularly needed 

given that the proposed states that tributaries need not be perennial (or even intermittent) 

waterbodies.

Neither the rule nor the preamble define “lake” or “pond.” But, consistent with the 

definition of tributary, the preamble notes that “[t]he flow in the tributary may be 

ephemeral, intermittent or perennial.” An ephemeral stream is one which flows briefly in 

direct response to precipitation in the immediate vicinity. Since “lakes” and “ponds” are 

tributaries, it appears that under the rule lakes and ponds might be jurisdictional even if 

they only contain water when there is nearby rain or snow melt.

Unlike wetlands, which contain specialized vegetation even when dry, under the rule 

ponds and lakes need not have such vegetation (or else they would be wetlands). Thus, 

without a specific definition of “lake” and “pond,” the implications of this part of the 

definition of tributary are unclear:

1. All water flows downhill. The preamble states that “[n]on-jurisdictional 

geographic features (e.g., non-wetland swales, ephemeral upland ditches) may 

still serve as a confined surface hydrologic connection between an adjacent 

wetland or water and a traditional navigable water, interstate water or the 

territorial sea.”

Many uphill areas are connected to downstream waters by surface water. Are all 

of these upstream areas lakes or ponds?

2. There is no clarity as to whether groundwater connectivity is sufficient to be 

the type of “direct contribution of flow” needed under the rule for a pond or lake 

to be a tributary. The preamble suggests that it may be, so long as the flow is not 

“lost to deep groundwater.”

Identifying groundwater connectivity would definitely require technical 

consultants – it cannot be seen by laypersons.

In short, it is unclear how lakes and ponds will be identified if they need not have a bed 

or bank, may not have to be wet much of the year, and can be connected to downstream 

waters by swales or other featureless forms (or possibly even underground flow).

We note that, in referring to a puddle over which they disclaim jurisdiction, the Agencies 

state that it “cannot reasonably be considered a water body or aquatic feature at all, 

because usually it exists for only a brief period of time before the water in the puddle 

evaporates or sinks into the ground.” This explanation reinforces our concern that the 

Agencies may consider other ephemeral waterbodies – if they contain water that flows 

downhill into another waterbody – as jurisdictional. Without specific definitions, this 

portion of the rule will be subject to future disagreement and litigation. (p. 23-24)
Clean Water Rule Response to Comments – Topic 8: Tributaries

429

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries.

Associated General Contractors of America (Doc. #14602)

8.256 The proposed rule categorically determines that tributaries have a significant nexus to 

traditional navigable waters, interstate waters, and the territorial seas.473 Likewise, waters 

and wetlands adjacent to tributaries will be automatically jurisdictional, under the 

proposal.474 Specifically, any channelized feature, including ditches and other man-made 

conveyances, no matter how remote from navigable waters, would be jurisdictional 

tributaries if they exhibit a bed, bank, and ordinary high water mark (OHWM). The 

proposed rule’s “tributary” definition vastly expands the scope of features that are 

currently regulated as tributaries, extending jurisdiction to features like ephemeral 

drainages and stormwater conveyances (e.g., roadside ditches) that have not been and 

should not be jurisdictional. The proposed rule’s two narrow ditch exclusions are unclear 

and unlikely to provide meaningful relief. (p. 5)

Agency Response: See summary response for “Relevance of Flow Regime” in 

section 8.1.1 of this RTC, particularly subsections on jurisdiction over intermittent 

and ephemeral waters and the legality of asserting jurisdiction over ephemeral 

waters. The agencies’ position in regard to tributaries is rooted in a science-based 

conclusion that such waters have a significant nexus either individually or in the

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion. The final rule is consistent with the agencies’ 

longstanding interpretation of the CWA that a tributary can be a natural, manaltered, or man-made water. Section IV(F) of the preamble to the final rule and 

section VII of the Technical Support Document discuss tributaries, including manmade or man-altered tributaries. See also the summary response for “Relevance of 

Flow Regime” in section 8.1.1 above, particularly the subsection on “Regulation of 

Man-Altered Streams” and the summary response for section 8.2 above, “Ditches as 

Tributary.” As defined in the final rule, “tributaries” thus include waters such as 

rivers, streams, canals, and ditches not excluded under paragraph (b). In addition to 

certain ditches, paragraph (b) also excludes many other features from being 

considered waters of the United States, including stormwater control features 

constructed in dry land. Section IV(I) of the preamble to the final rule and the 

summary responses in Compendium 7 of this RTC, “Features and Waters Not 

Jurisdictional,” provide a broad discussion of the final rule’s exclusions. See 

summary response for section 6.2, “Excluded Ditches” in this RTC for a more 

focused discussion of revised and clarified ditch exclusions.

 

473 See 79 Fed. Reg. at 22,201.

474 Id. at 22,263.
Clean Water Rule Response to Comments – Topic 8: Tributaries

430

Vulcan Materials Company (Doc. #14642)

8.257 The rule includes exemptions for rills and gullies from being considered waters; however, 

the inclusion of ditches combined with the bed and bank criteria creates uncertainty and 

confusion regarding the upper reach of jurisdiction that the agencies may pursue. In the 

case of aggregate mining operations, this extension is unnecessary as the mine sites are 

subject to National Pollutant Discharge Elimination System (NPDES) permitting for 

process and storm water discharges either under the federal program or federally 

delegated state permitting programs. These NPDES permits require aggregate mining 

sites to employ best management practices to control erosion and sediment discharges 

and to use water treatment systems with settling ponds and/or other treatment methods to 

ensure that discharges to surface waters are in compliance with applicable water quality 

criteria. (p. 2)

Agency Response: See summary response in Section 6.2 of the Ditches 

compendium for a discussion of how the proposed exclusions for ditches were edited 

and clarified for the final rule. Only those ditches meeting the definition of 

“tributary” in the final rule and that are not excluded under paragraph (b) will be 

waters of the United States. Section I of the Technical Support Document provides 

the legal framework under which a ditch could be considered both a point source 

and a water of the United States.

8.258 The proposed rule’s inclusion of man-altered, or man-made water and ponds, 

impoundments, canals and ditches as tributaries is problematical. This inclusion raises the 

potential for water management systems employed by facilities to be subject to full CWA 

jurisdiction. These engineered systems manage stormwater runoff, collect and treat water 

prior to discharge, and provide a means for water re-use and recycling thereby 

minimizing the consumption of surface and groundwater resources. As previously stated, 

the management of stormwater and process water at aggregate mining operations is 

already subject to regulation under the NPDES program or federally authorized and 

equivalent state or local programs and additional regulation under the CWA is therefore 

not necessary. (p. 2)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries. The final rule is consistent with the agencies’ 

longstanding interpretation of the CWA that a tributary can be a natural, manaltered, or man-made water. Section IV(F) of the preamble to the final rule and 

section VII of the Technical Support Document discuss tributaries, including manmade or man-altered tributaries. See also the summary response for “Relevance of 

Flow Regime” in section 8.1.1 above, particularly the subsection on “Regulation of 

Man-Altered Streams” and the summary response for section 8.2 above, “Ditches as 

Tributary.” As defined in the final rule, “tributaries” thus include waters such as 

rivers, streams, canals, and ditches not excluded under paragraph (b). In addition 

to certain ditches, paragraph (b) also excludes many other features from being 

considered waters of the United States, including stormwater control features 

constructed in dry land, waste treatment systems designed to meet the requirements 

of the CWA and wastewater recycling structures created in dry land. Section IV(I) 

of the preamble to the final rule and the summary responses in Compendium 7 of 
Clean Water Rule Response to Comments – Topic 8: Tributaries

431

this RTC, “Features and Waters Not Jurisdictional,” provide a broad discussion of 

the final rule’s exclusions. See summary response for section 6.2, “Excluded 

Ditches” in this RTC for a more focused discussion of revised and clarified ditch 

exclusions. Note also that Section I of the Technical Support Document provides the 

legal framework under which a ditch could be considered both a point source and a 

water of the United States.

National Association of Home Builders (Doc. #19540)

8.259 6. The Tributary Definition Unlawfully Includes Ditches.

The proposed rule explicitly includes ditches in its definition of tributaries. The Agencies 

state that “a tributary, including wetlands, can be a natural, man-altered, or man-made 

water and includes waters such as rivers, streams, lakes, ponds, impoundments, canals, 

and ditches not excluded.”475 Ditches are only excluded from the definition of “waters of 

the United States” if they meet one of two very limited exclusions. Excluded ditches are 

those “that are excavated wholly in uplands, drain only uplands, and have less than 

perennial flow” and those “that do not contribute flow, either directly or through another 

water,” to an (a)(1) through (4) water.476

The issue of ditches is critically important because ditches are pervasive and endemic to 

every type of landscape and human activity across the country. Historically, most ditches 

have not been regulated as “waters of the United States” under the CWA. Because 

ditches are expressly included in the tributary definition, all ditches with a bed, bank, and 

OHWM that contribute flow to an (a)(1) through (4) water will be per se jurisdictional 

unless they meet one of the two narrow exclusions. The categorical regulation of ditches 

represents an expansion from current practice and an impingement on traditional state 

and local authority over water and land use. Additionally, ditches are already specifically 

identified as point sources in CWA Section 502(14) and therefore are protected under 

CWA Section 402.477 In other words, they do not need to be regulated as “waters of the 

United States” for the Agencies to ensure their protection.

The Agencies have historically taken the position that ditches are not “waters of the 

United States,” but they have gradually expanded claims of jurisdiction over ditches 

without any change in the law. The Corps’s 1975 regulations stated that “[d]rainage and

irrigation ditches have been excluded” from CWA jurisdiction.478 Their 1977 regulations 

read similarly: “[M]anmade nontidal drainage and irrigation ditches excavated on dry 

land are not considered waters of the United States under this definition.”479 The 

preamble of the 1977 regulations indicated that ditches, if they were to be regulated at all, 

were meant to be regulated as point sources and not “waters of the United States”: 

“[N]ontidal drainage and irrigation ditches that feed into navigable waters will not be 

considered ‘waters of the United States’ under this definition. To the extent that these 

 

475 79 Fed. Reg. at 22,263 (emphasis added).

476 Id.

477 33 C.F.R. § 1362.14; 33 C.F.R. § 1342.

478 40 Fed. Reg. 31,320 and 31,321 (July 25, 1975).

479 42 Fed. Reg. 37,112 (1977).
Clean Water Rule Response to Comments – Topic 8: Tributaries

432

activities cause water quality problems, they will be handled under other programs of the 

FWPCA, including Section 208 and 402.”480

Nevertheless, the Agencies’ position on ditches has shifted over time, beginning in the 

mid- to late- 1980s, when they began treating ditches as “waters of the United States” in 

the context of Section 404 on a case-by-case basis, using OHWM and the Migratory Bird 

Rule tests.481 The preamble of the 1986 regulations continued to maintain the exclusion 

for ditches stating, “We generally do not consider [drainage and irrigation ditches 

excavated in dry land] to be ‘Waters of the United States."482 However, the same 

regulations included a provision for the Corps to assert regulatory authority on a "caseby-case" basis to claim jurisdiction after all.483 Similarly, EPA had historically refrained 

from regulating ditches as "waters of the United States," and did not even discuss the 

possibility that ditches might be "waters of the United States" until 1988 when they 

included reservation of "case-by-case" authority to regulate upland ditches as "waters of 

the United States" under Section 404. It's clear the Agencies, without any congressional 

authorization, have incrementally expanded claims of jurisdiction over ditches. To make 

matters worse, the proposed rule goes even further. 

With the proposed tributary definition, the Agencies claim of jurisdiction over ditches has 

expanded exponentially. For the first time, the Agencies are categorically regulating 

ditches under all CWA programs. In the past, the Agencies have said that, for the 

purposes of the Section 404 program, some ditches could be regulated as "waters of the 

United States" on a case-by-case basis.484 Indeed, that is a far cry from categorically 

regulating all ditches as "waters of the United States" under all CWA programs, unless 

they meet one of two very narrow exclusions. Under the proposed rule, the Agencies will 

regulate all ditches with a bed, bank, and OHWM that contribute flow to a traditional 

navigable water, interstate water, territorial sea, or impoundment.485 This includes 

irrigation ditches, roadside ditches, MS4 ditches and other stormwater conveyance 

ditches. Treating all of these features, many of which are in place to meet the goals of the 

CWA, as per se jurisdictional for the purpose of all CWA programs will vastly expand 

CWA jurisdiction. Adding insult to injury, even if ditches do not meet the tributary 

definition, the proposed rule allows for them to be jurisdictional as either "adjacent 

waters" or "other waters."

Regulating ditches is not what Congress had in mind when enacting the CWA or what the 

Supreme Court deemed prudent in Rapanos. The Agencies' overbroad treatment of 

ditches as tributaries indeed stretches the term "waters of the United States" beyond 

parody. (p. 71-72)

 

480 Id. at 37,127.

481 See e.g., 65 Fed. Reg. at 12818, 12823, 12824 (Mar. 9, 2000) (In the 2000 nationwide permit [NWP] regulations, 

the Corps’s disapproval of jurisdiction shrank to “ditches constructed entirely in upland areas,” finding that non-tidal 

drainage ditches are waters of the United States if they extend the OHWM of an existing water of the United States.)

482 51 Fed. Reg. at 41,217.

483 Id.

484 Id.

485 79 Fed. Reg. at 22,262,22263.
Clean Water Rule Response to Comments – Topic 8: Tributaries

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Agency Response: See the summary responses for Sections 8.1 and 8.2. See 

summary response for Section 6.2 in the Ditches compendium of this RTC for a 

history of CWA regulatory jurisdiction of ditches. Section I of the Technical 

Support Document further discusses the historic scope of the regulatory definition 

of “waters of the United States,” and also provides a broader discussion of the legal 

basis of the final rule, including consistency with the statute and Supreme Court 

decisions. Section I of the Technical Support Document also provides the legal 

framework under which a ditch could be considered both a point source and a 

water of the United States. The final rule is consistent with the agencies’ 

longstanding interpretation of the CWA that a tributary can be a natural, manaltered, or man-made water. Section IV(F) of the preamble to the final rule and 

section VII of the Technical Support Document discuss tributaries, including manmade or man-altered tributaries. See also the summary response for “Relevance of 

Flow Regime” in section 8.1.1 above, particularly the subsection on “Regulation of 

Man-Altered Streams” and the summary response for section 8.2 above, “Ditches as 

Tributary.” As defined in the final rule, “tributaries” thus include waters such as 

rivers, streams, canals, and ditches not excluded under paragraph (b). The 

summary response in Section 6.2 of the Ditches compendium discusses how the 

proposed exclusions for ditches were edited and clarified for the final rule. The 

agencies believe that these exclusions ensure for the first time by rule that most 

ditches will not be considered waters of the United States

8.260 7. Defining Wetlands as Tributaries is Absurd and will Increase Regulatory 

Confusion.

Although the Agencies claim the proposed rule provides increased clarity regarding what 

waters are and are not "waters of the United States," the very definitions used to describe 

categorically jurisdictional waters only further muddy the waters.

For instance, the Agencies' definition of tributary contradicts itself. In the preamble, the 

Agencies state, "[a] tributary is a longitudinal surface feature that results from directional 

surface water movement and sediment dynamics demonstrated by the presence of bed 

and banks, bottom and lateral boundaries, or other indicators of OHWM."486 Later, under 

the definitions section of the proposed rule, the Agencies basically reiterate the preamble, 

stating, "the term tributary means a water physically characterized by the presence of a 

bed and banks and ordinary high water mark . . . which contributes flow . . ."487 to an 

(a)(l) through (4) water. Immediately following the requirement for these physical traits, 

however, the definition disagrees with itself, stating, "wetlands, lakes, and ponds are 

tributaries (even if they lack a bed and banks or ordinary high water mark) . . . 

488

This turn of events makes no sense. Fist, this definition differs from the definition of 

tributary provided in the draft Connectivity Report as well as the description provided in 

the preamble. Which one is to be believed? Second, it is nonsensical to state that a 

tributary requires a bed, bank, and OHWM and then suggest that a tributary may lack 

 

486 Id.

487 79 Fed. Reg. at 22,263.

488 Id. at. 2 2,263 (emphasis added).
Clean Water Rule Response to Comments – Topic 8: Tributaries

434

these defining features. Fortunately, the Agencies specifically request comment on 

whether wetlands, lakes, and ponds should be considered tributaries. The answer is a 

resounding "no." The Agencies must correct this inconsistency by simply removing 

wetlands, lakes, and ponds from the tributary definition.

NAHB, along with several EPA SAB panel members, note these waterbodies would 

already be jurisdictional under the proposed "adjacent waters" definition. 489Wetlands, 

lakes, and ponds are lentic ecosystems and not commonly considered tributaries -not by 

freshwater ecologists or the Merriam-Webster Dictionary.490 Clearly, the Agencies 

should not define wetlands as tributaries. It is inconsistent with the Agencies' own 

definition, scientific literature, and common sense and will unnecessarily increase 

regulatory confusion. What's more, inclusion of wetlands in the tributary definition would 

render the Supreme Court's ruling in Riverside Bayview laughable. Riverside Bayview

addressed the question whether the CWA authorizes the Corps to assert jurisdiction over 

wetlands adjacent to traditional navigable waters. The Supreme Court ruled in Riverside 

Bayview that adjacent wetlands are jurisdictional.491 By defining wetlands as tributaries, a 

wetland adjacent to a wetland that is itself adjacent to a tributary in the traditional sense 

would be "jurisdictional by rule because the intervening wetland would he deemed a 

tributary. This "stepping stone" interpretation of wetlands as tributaries could be extended 

indefinitely to wetlands far removed from traditional navigable waters if a string of a 

wetland adjacent to a wetland adjacent to a wetland - and so on - exists between the 

wetland in question and a tributary in the traditional sense. Surely this was not what the 

Supreme Court had in mind in Riverside Bayview. It is quite plain and simple: wetlands 

are not tributaries and tributaries are not wetlands. (p. 72-73)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries.

New Mexico Mining Association (Doc. #8644)

8.261 Comment 4: The definition of tributary under subsection (a)(5) should be amended 

to exclude Wetlands, Lakes, or Ponds which contribute flow to a Water of the 

United States.

 

489 SAB Chair Dr. Amanda Rodewald and SAB panel member Dr. Mazeika Sullivan both assert that wetlands

should not be included in the tributary definition as wetland jurisdiction is already be addressed under the adjacent 

waters definition (8114114 Preliminary comments from individual members of the SAB Panel for the Review of the 

EPA Water Body Draft Connectivity Report).

490 EPA Office of Research and Development scientists define tributary as "a stream or river that flows into a

higher-order stream or river" Draft Connectivity Report at A-20; In 8114114 preliminary comments from individual

members of the SAB Panel for the Review of the EPA Water Body Draft Connectivity Report at 10, Dr. Genevieve

Ali commented, "I am not sure that the majority of the literature supports the categorization of run-of stream

wetlands and lakes as tributaries, especially since the majority of the literature defines tributaries as longitudinal

features that have directional flow"; Tributary [Def. 21. (n.d.). In Merriam-Webster-Online, Retrieved October 8,

2014, from http://www.merriam-webster.com/dictionary/tributary.

491 Riverside Bayview, 474 U.S. at 121.
Clean Water Rule Response to Comments – Topic 8: Tributaries

435

Wetlands, Lakes, and Ponds should not be included in the definition of tributary under 

subsection (a)(5). These water bodies should only be jurisdictional by rule if they satisfy 

the definition of adjacent under subsection (a)(6).

Currently, the proposed rule provides two distinct methods by which a Wetland, Lake, or 

Pond may be considered jurisdictional by rule. Under (a)(5), a Wetland, Lake, or Pond is 

a jurisdictional "tributary" if it contributes flow to another Water of the United States. 

And then under (a)(6), a Wetland, Lake or Pond may be deemed a jurisdictional 

"adjacent" water if it includes a hydrological connection with another Water of the United 

States.

These dual approaches to Wetlands, Lakes, or Ponds are redundant and would be 

confusing to a land manager or owner seeking clear guidance on whether their water 

body is subject to the agencies' jurisdiction. Aside from Wetlands, Lakes, or Ponds, the 

definition of tributaries includes only those water features with a bed and bank and 

ordinary high water mark Water bodies without a bed and bank and ordinary high water 

mark are more logically addressed through the adjacency determination of (a)(6). Thus, 

the final rule should only consider whether a Wetland, Lake, or Pond falls within the 

determination of adjacency under subsection (a)(6). (p. 3-4)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries.

Kansas Independent Oil & Gas Association (Doc. #12249)

8.262 Within the discussion of tributaries is included the awkward discussion of the regulatory 

management of ditches. For upland ditches the agencies reference past policies, but 

express concern over flow and what regime should be defined, perennial or intermittent. 

Nonjurisdictional ditches become tributaries if they have beds and banks and ordinary 

high water marks and contribute flow. The preamble discussion lists those ditches that 

may be deemed jurisdictional. The proposal discusses flow relative to downstream 

traditional navigable waters. This proposed regulatory discussion is, again, part of the 

expansion of the scope of "waters of the United States." Rather than certainty, this 

regulation creates uncertainty as to current operations and future impacts on the status of 

ditches. (p. 14-15)

Agency Response: The summary in Section 6.2 of the Ditches compendium 

discusses how the proposed exclusions for ditches were edited and clarified for the 

final rule. The final rule is consistent with the agencies’ longstanding interpretation 

of the CWA that a tributary can be a natural, man-altered, or man-made water. 

Section IV(F) of the preamble to the final rule and section VII of the Technical 

Support Document discuss tributaries, including man-made or man-altered 

tributaries. See also the summary response for “Relevance of Flow Regime” in 

section 8.1.1 above, particularly the subsection on “Regulation of Man-Altered 

Streams” and the summary response for section 8.2 above, “Ditches as Tributary.” 

As defined in the final rule, “tributaries” thus include waters such as rivers, 

streams, canals, and ditches not excluded under paragraph (b). The agencies 
Clean Water Rule Response to Comments – Topic 8: Tributaries

436

believe that these exclusions ensure for the first time by rule that most ditches will 

not be considered waters of the United States.

Alliance Coal, LLC (Doc. #14577)

8.263 ...the Agencies define "tributary" as any water "physically characterized by the presence 

of a bed and banks and ordinary high water mark ... which contributes flow, either 

directly or through another water," to a traditional navigable water, interstate water, 

territorial sea, or jurisdictional impoundment. Tributaries are per se jurisdictional 

regardless of whether they contribute perennial, intermittent, or ephemeral flow.492 And 

for the first time, "waters of the United States" explicitly includes ditches that meet the 

new definition of tributary.493 Even "wetlands, lakes, and ponds" that lack a bed, bank, 

and ordinary high water mark can be tributaries (and hence per se jurisdictional), as long 

as they "contribute flow, either directly or through another water" to a traditional 

navigable water, interstate water, or territorial sea.494 Under this new concept of" 

tributary," it is likely that many, if not most, ditches, as well as certain ponds and other 

water management features on mine sites, would fall within that definition based solely 

on contribution of flow , no matter how insubstantial or indirect. Indeed, man y on-site 

water features are permitted under Section 402 to discharge to "waters of the United 

States" because of such connections. As explained in greater detail below, many such 

features do not fit neatly into any of the exclusion categories in the proposal, and as such 

would become federal waters under the new rule. (p. 2-3)

Agency Response: See the summary responses for Sections 8.1 and 8.2. See 

summary response for Section 6.2 in the Ditches compendium of this RTC for a 

history of CWA regulatory jurisdiction of ditches. Section I of the Technical 

Support Document further discusses the historic scope of the regulatory definition 

of “waters of the United States,” and also provides a broader discussion of the legal 

basis of the final rule, including consistency with the statute and Supreme Court 

decisions. The summary response in Section 6.2 of the Ditches compendium 

discusses how the proposed exclusions for ditches were edited and clarified for the 

final rule. The agencies believe that these exclusions ensure for the first time by rule 

that most ditches will not be considered waters of the United States.

8.264 ...even if on-site waters at mines are somehow outside of the definitions of "tributary" or 

"adjacency, " which are per s e jurisdictional, they could nevertheless be deemed 

jurisdictional "other waters" on a "case-specific basis" through application of the 

"significant nexus" test in the proposed rule.495 An on-site water management feature at a 

mine, either alone or when aggregated with "similarly situated" waters in the same 

region, could be deemed to significantly affect the chemical, physical, or biological 

integrity of a traditional navigable water, interstate water, or territorial sea so long as it 

has more than a speculative or insubstantial effect on such a downstream jurisdictional 

water. As an example, biota movement among otherwise isolated onsite water 

 

492 Id. at 22,202.

493 See id. at 22,263.

494 Id.

495 See id. at 22,263.
Clean Water Rule Response to Comments – Topic 8: Tributaries

437

management features such as settling ponds and a jurisdictional water may be all that is 

needed to trigger Clean Water Act jurisdiction under this new test. (p. 3)

Agency Response: The exclusions at paragraph (b) of the final rule include many 

features in addition to ditches, such as waste treatment systems designed to meet the 

requirements of the CWA, stormwater control features created in dry land, water 

filled depressions created in dry land incidental to mining or construction activity

and artificial lakes and ponds created in dry land. Section IV(I) of the preamble to 

the final rule and the summary responses in Compendium 7 of this RTC, “Features 

and Waters Not Jurisdictional,” provide a broad discussion of the final rule’s 

exclusions. See summary response for section 6.2, “Excluded Ditches” in this RTC 

for a more focused discussion of revised and clarified ditch exclusions.

Devon Energy Corporation (Doc. #14916)

8.265 Even if ditches do not have bed, bank and OHWM and so are not tributaries, the 

Proposed Rule allows for them to be jurisdictional as “adjacent waters” or “other waters.” 

Key terms like “uplands” and “contribute flow” are undefined and therefore do not 

provide the stakeholder with any guidance to determine what ditches are affected and 

which are exempted. Also, if shallow groundwater enters ditches and creates perennial 

flow, then they are likely jurisdictional. (p. 6)

Agency Response: Paragraph (b) of the final rule makes clear that the features 

identified therein “are not waters of the United States even where they otherwise 

meet the terms of paragraphs (a)(1) through (a)(8)” of the rule. Thus, a ditch or any 

other excluded feature may not be considered waters of the United States under any 

other provision of the rule. Section IV(I) of the preamble to the final rule discusses 

the rule’s the exclusions, and the summary response for section 6.2, “Excluded 

Ditches,” in this RTC addresses the ditch exclusions more specifically.

Sinclair Oil Corporation (Doc. #15142)

8.266 ...Sinclair is not confident that the ditches that convey wastewater to the evaporation 

ponds [and around the properties located adjacent to the refineries], wouldn't be deemed 

"waters of the United States" as "tributaries" under the definition contained in the 

proposed rule.

The proposed rule determines whether a surface feature is or isn't a tributary based on 

whether or not it contributes flow. But the proposed rule does not clearly articulate what 

it means to contribute flow and does not limit the manner in which that flow must be 

contributed for a water to become jurisdictional. For example, the preamble to the 

proposed rule specifically provides that any amount of flow contributed in any manner, 

including through shallow groundwater, would be sufficient to make an othe1wise 

isolated ditch a "water of the United States." 79 Fed. Reg. 22,203. However, the 

contribution of marginal amounts of flow is not sufficient to establish a significant nexus 

under the standard the Agencies assert they are applying. Rapanos, 547 U.S. at 784 ("a 

mere hydrologic connection should not suffice in all cases; the connection may be too 

insubstantial for the hydrologic linkage to establish the required nexus with navigable 

waters as traditionally understood"). The proposed definition simply goes too far and 

Sinclair could be deemed in violation of the CWA, for operating its RCRA-permitted 
Clean Water Rule Response to Comments – Topic 8: Tributaries

438

waste treatment system, based on nothing more than an assertion of subsurface 

connectivity between the waste water ditch, evaporation ponds or flood irrigation area 

and "waters of the United States."496 These man-made ditches, carrying waste water at a 

zero discharge industrial facility are simply not the types of waters allowed to be included 

in the definition of "waters of the United States" by SWANCC and Rapanos. 11 (p. 13-14)

Agency Response: Paragraph (b) of the final rule excludes wastewater treatment 

systems designed to meet the requirements of the CWA. Paragraph (b) of the final 

rule also makes clear that the features identified therein “are not waters of the 

United States even where they otherwise meet the terms of paragraphs (a)(1) 

through (a)(8)” of the rule. Thus, a ditch or any other excluded feature may not be 

considered waters of the United States under any other provision of the rule.

Ohio Coal Association (Doc. #15163)

8.267 The Rule Should Not Permit Federal Jurisdiction on the Basis of Surface 

Connections or Contributions of Flow that are Ephemeral or Intermittent.

In two instances, the Proposed Rule permits jurisdiction over waters based on the vague 

and undefined concepts of ephemeral and intermittent surface connections. First, the 

Proposed Rule states that a wetland, lake or pond that contributes even ephemeral or 

intermittent flow to a water identified in (a)(1) through (a)(3), is a tributary and 

jurisdictional under (a)(5). See 79 Fed. Reg.22202....The Proposed Rule's use of 

ephemeral and intermittent connections is both unclear and over-expansive. Such an 

expansive approach is well beyond the "significant nexus" standard and greatly expands 

federal jurisdiction beyond applicable law or common sense. As such, these concepts 

should be removed. (p. 3)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries.

National Sustainable Agriculture Coalition (Doc. #15403)

8.268 We are generally supportive of providing clarity to the regulated community by 

establishing tributaries to traditionally navigable waters, interstate waters, territorial seas, 

and impoundments ((a)(1) through(4) waters) as per se jurisdictional. Tributaries, 

especially headwater tributaries, greatly affect the chemical, physical, and biological 

integrity of (a)(1) through (4) waters by contributing flow and pollutants, impacting the 

geomorphology of the water bodies, and providing additional aquatic habitat. Given the 

impact of tributaries, it would be unreasonable to argue that they lack a significant nexus 

to waters of the United States.

The current definition of tributary in the proposed rule provides descriptions of physical 

demarcations—a bed and banks along with an ordinary high water mark—that would 

help landowners easily identify a tributary on their property. The inclusion of wetlands as 

 

496 Moreover, since the proposed rule provides that ditches that contribute flow to an impoundment of a "water of 

the United States" are tributaries, the ditches and drains at Sinclair's refineries would be considered tributaries if the

evaporation ponds were considered "impoundments." 79 Fed. Reg. 22,201.
Clean Water Rule Response to Comments – Topic 8: Tributaries

439

potential tributaries, however, introduces more confusion than clarity. As acknowledged 

in the rule, wetlands can serve as tributaries by contributing flow to a jurisdictional water 

either directly or through another water. Although these wetlands may warrant 

jurisdiction, not all wetlands contribute flow to (a)(1)through (4) waters and, as such, 

could not be classified as tributaries. The inclusion of wetlands as possible tributaries 

effectively rescinds any clarity provided by the bed, banks, and ordinary high water mark 

criteria previously established.

While this vagueness may work for lakes or ponds lacking an ordinary high water mark 

where contribution of flow to a jurisdictional water would be more obvious, such a 

connection would be less apparent when it comes to wetlands. We do not dispute that 

wetlands can contribute flow—either directly or through another water—and act as a 

tributary, but for the sake of reducing ambiguity, it would be best to reconsider this 

addition of wetlands to the tributary definition. Wetlands directly contributing flow to a 

traditionally navigable water would be considered adjacent waters and would therefore 

remain jurisdictional. Non-adjacent wetlands with a more obscure connection to 

traditionally navigable waters could still be jurisdictional as “other waters” pending a 

significant nexus determination.

Recommendation: Remove wetlands from the definition of tributary, covering them 

instead as either adjacent waters or other waters subject to a significant nexus test. (p. 3)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries.

Pennsylvania Aggregates and Concrete Association (Doc. #16353)

8.269 8. The Proposed Rule’s Treatment of Tributaries and Ditches is Not Supported by 

Science, Will Result in Confusion in the Field, and Infringes upon State and Local 

Authority.

The proposed rule’s “tributary” definition vastly expands the scope of features that are 

currently regulated as tributaries and gives jurisdiction to areas such as ephemeral 

drainages, which may only flow in response to precipitation, and stormwater 

conveyances, which should not be jurisdictional. The proposed rule states this includes 

ditches, explicitly stating that “rivers, streams, lakes, ponds, impoundments, canals, and 

ditches” are tributaries. Neither the Connectivity Report nor Appendix A of the proposed 

rulemaking preamble demonstrates that ephemeral features have significant chemical, 

physical and biological effects on traditional navigable waters. Additionally, the proposed 

rule draws an arbitrary distinction between erosional features and ephemeral drainages.

In Pennsylvania, agriculture is the leading economic enterprise. The inclusion of ditches 

in this proposed rulemaking is significant because ditches are found on every type of 

landscape across the Commonwealth of Pennsylvania— agricultural irrigation, homes, 

pipelines, electric generation facilities and transmission/distribution lines, transportationrelated infrastructure including roads and railways, flood control, rural drains and roads, 

and mines. This regulation of ditches expands the current practice and encroaches on 

traditional State and local authority over water and land use. Ditches do not need to be 

regulated as “waters of the U.S.” to ensure protection, because the CWA regulates them 
Clean Water Rule Response to Comments – Topic 8: Tributaries

440

in other ways such as point sources. Since the Commonwealth of Pennsylvania is already 

charged with controlling stormwater volume through their NPDES program, there is no 

environmental benefit by treating these ditches as jurisdictional “waters of the U.S.”

Additionally, waters should not be considered tributaries regardless of man-made and 

natural breaks “for any length.” Such breaks can sever connectivity, even when a channel 

can be identified upstream.

Furthermore, the proposed rule’s definition of tributary is overly broad and is inconsistent 

with the Rapanos Plurality and Justice Kennedy’s opinions, which made it very clear that 

many ditches are excluded from jurisdiction, even those that connect waters of the United 

States. (p. 5)

Agency Response: See the summary responses for Sections 8.1 and 8.2. See 

summary response for Section 6.2 in the Ditches compendium of this RTC for a 

history of CWA regulatory jurisdiction of ditches. Section I of the Technical 

Support Document further discusses the historic scope of the regulatory definition 

of “waters of the United States,” and also provides a broader discussion of the legal 

basis of the final rule, including consistency with the statute and Supreme Court 

decisions. The summary response in Section 6.2 of the Ditches compendium 

discusses how the proposed exclusions for ditches were edited and clarified for the 

final rule. The agencies believe that these exclusions ensure for the first time by rule 

that most ditches will not be considered waters of the United States. The agencies’ 

position in regard to tributaries is rooted in a science-based conclusion that such 

waters have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

conclusion. Section IV(F) of the preamble to the final rule discusses the agencies’ 

conclusion that waters that meet the rule’s definition of tributary remain tributaries 

even if there is a manmade or natural break at some point along the connection to 

the traditional navigable water, interstate water, or the territorial seas.

National Farmers Union (Doc. #6249)

8.270 ... the proposed rule treats wetlands that are connected to tributaries as tributaries 

themselves, but the preamble requests comment on this approach and offers an 

alternative. Wetlands should not be considered tributaries. Treating wetlands as 

tributaries would negate the bed, bank and OHWM criteria the Corps uses for identifying 

tributaries. The agencies should enact the alternative proposed in the preamble and 

"clarify that wetlands that connect tributary segments are adjacent wetlands, and as such 

are jurisdictional waters of the United States under (a)(6)." This alternative creates a 

bright-line definition for "tributary" without relinquishing any opportunities to protect 

water resources. (p. 3-4) 

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries.
Clean Water Rule Response to Comments – Topic 8: Tributaries

441

Alameda County Cattlewomen (Doc. #8674)

8.271 The plain language of the definition of tributary encompasses numerous isolated and, in 

many cases, dry features that are far beyond the agencies' authority under the CWA. It 

would encompass isolated ponds not otherwise excluded that somehow be connected 

through a surface connection, groundwater, or any other connection to a nearby (a)(1) 

through (4) water. It encompasses isolated wetlands in pastures that may be connected to 

a nearby creek through ground water or ditches. It encompasses virtually all artificial 

stock ponds west of the Mississippi River, of which, virtually all will have been built on a 

drainage (ephemeral streams) in order to fill with water. It is clear that the plain language 

of the definition makes the category almost limitless.

NCBA and PLC assert that the agencies' definition of "tributary" is a limitless category 

that has the potential to wrap every natural pond, isolated wetland, or ditch into the 

federal regulatory scheme, which violates the language and spirit of the Supreme Court's 

decisions in SWANCC and Rapanos.

497

 It is clear that the phrase "waters of the U.S." is 

not limitless, yet that is exactly what the agencies have proposed through their broad and 

ill-defined term "tributary." Key phrases have been left undefined. The definition for 

"through another water," a key phrase in the definition, was simply left out by the 

agencies. Not only does this foster confusion instead of clarity in the regulated 

community, it could be stretched by regulators or litigants now or in the future. If the 

agencies' intent was not to create such a broad definition, than they should have put such 

intent in the regulation. ACCW members cannot "take agency officials' word for it." (p. 

7-8)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries. The agencies do not believe that the definition of 

“tributary” in the final rule is a “limitless category that has the potential to wrap 

every natural pond, isolated wetland, or ditch into the federal regulatory scheme.” 

Section I of the Technical Support Document provides a discussion of the legal basis 

of the final rule, including consistency with the statute and Supreme Court 

decisions. The agencies’ position in regard to tributaries is rooted in a science-based 

conclusion that such waters have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion.

8.272 A dry ditch could be a "water of the U.S." under the proposed definition if it flows once 

per year but drains to a jurisdictional creek. Is it truly the agencies intent to capture all 

ditches that ever drain to a larger ditch that then drains to creek or other water the agency 

defines as a TNW? If not, the agencies should make that clear. American ranches 

 

497 Rapanos v. United States, 547 U.S. 715 (2006); (J. Scalia, Indicating "navigable" invokes a limit on the CWA

jurisdiction the plurality stated"... that the qualifier "navigable" is not devoid of significance...the waters of the

United States in 1362(7) cannot bear the expansive meaning that the Corps would give it"); SWANCC v. U.S. Army

Corps of Engineers, 531 U.S. 159 (2001); (In striking down the agencies' Migratory Bird Rule the court stated, "we

find nothing approaching a clear statement from Congress that it intended 404(a) to reach an abandoned sand and

gravel pit such as we have here").
Clean Water Rule Response to Comments – Topic 8: Tributaries

442

throughout the United States have millions of these features dotted across their 

landscapes. Let us be clear, DITCHES DRAIN! That is their purpose. They will be 

connected eventually leading to some other jurisdictional water, therefore all ditches will 

be jurisdictional. The agencies' use of the phrase "through another water" could remove 

all ditches from the excluded categories and could make them jurisdictional. Making 

these features jurisdictional would cripple the production of food and fiber across this 

country by requiring permits to conduct many routine activities no longer exempt under 

different sections of the CWA due to the agencies' new interpretation of the 404(f)(I)(A) 

exemption for "normal farming, silviculture and ranching activities." Ditches should not 

be per se jurisdictional tributaries.

ACCW assert that the agencies have underestimated how many ditches will be captured 

by their proposed definition of "tributaries" and therefore have not adequately analyzed 

their impact on downstream jurisdictional waters to categorically say they have a 

"significant nexus" to these downstream jurisdictional waters. The definition of tributary 

captures different features of size and scope which will have varying effects on TNWs. 

These differences are too great to categorically find anything with a bed, bank and 

OHWM that ever contributes flow will have a significant nexus to downstream 

jurisdictional waters

The exclusions provided by the agencies for ditches are addressed in Sec. III.b. below, 

but as they are included under the definition of tributary they are addressed here as well. 

ACCW strongly believe that very few, if any, ditches will actually fall into the (b)(3) or 

(b)(4) categories of the proposed definition. EPA and the Corps should show the 

American public on maps, by state, how many ditches will be jurisdictional and how 

many will not. The agencies should also map the sheer expanse of their proposed 

definition and respond to maps presented to the agencies from industry showing our 

projection and interpretation of their proposed definition. It is our understanding that the 

agencies were provided these types of maps by the U.S. Geological Service (USGS), but 

the agencies failed to provide this important information to the American public, which 

would have provided a clear picture to everyone exactly what the expansion of the 

proposed rule would be. Because the maps were not provided to the public by EPA in a 

timely manner, the public has not had adequate time to analyze and ultimately, comment 

on them. Precluding the public from having the ability to meaningfully comment is a 

violation of the APA. (p. 9-10)

Agency Response: It is not the agencies intent to capture all ditches as waters of 

the United States. The summary in Section 6.2 of the Ditches compendium discusses 

how the proposed exclusions for ditches were edited and clarified for the final rule. 

The agencies believe that these exclusions ensure for the first time by rule that most 

ditches will not be considered waters of the United States. Paragraph (b) of the final 

rule also makes clear that the excluded features identified therein “are not waters of 

the United States even where they otherwise meet the terms of paragraphs (a)(1) 

through (a)(8)” of the rule. Thus, neither an excluded ditch nor any other excluded 

feature may be considered waters of the United States under any other provision of 

the rule. The agencies do not have maps depicting waters of the United States under 

either present regulatory standards or those in the final rule. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

443

8.273 ...if the intent is to provide clarity to the regulated public, the agencies should give terms 

their common meaning. The term “tributary” to most landowners in the country is going 

to be a flowing feature like a river, creek, or stream. Ponds and wetlands are not what 

most would consider a “tributary” and therefore ACCW request the agencies to remove 

ponds, wetlands and any other non-flowing feature from inclusion in the definition of 

“tributary.” ACCW encourage the agency to withdraw the proposed rule, convene 

stakeholder discussions to address these important issues and ways the agencies can 

legally address any concerns that they have. As it is currently written, the definition of 

“tributary” under the proposed rule goes far beyond what the Supreme Court has 

articulated as a limit to federal jurisdiction. (p. 11-12)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries

Michigan Farm Bureau (Doc. #10196)

8.274 Further, EPA and USACE defy their own definition of tributary by extending the term to 

include wetlands, ponds, and lakes even if they lack a bed, bank, or ordinary high water 

mark, so long as they contribute flow directly or indirectly to a jurisdictional water. 

Again the significance of that connection is missing from the definition, and lacking any 

requirement for testing of the significance of a connection downstream, this extends EPA 

and USACE's jurisdiction to virtually any water on the landscape regardless of its 

position or connection. Wet spots in farm fields regardless of size, isolated vernal pools 

in woodlots, and broken water features across the landscape that may in fact be dry most 

of the year could fall under this regulatory definition. This gives farmers and landowners 

no certainty whatsoever unless that certainty is that if any water sits anywhere on their 

property it will be regulated. EPA and USACE's assurances that these definitions are 

consistent with past practice and interpretation gives farmers and landowners no relief, as 

several court battles in which agency interpretations have been limited demonstrate (e.g., 

Rapanos, SWANCC, U.S. v Wilson, 133 F.3d 251 (4th Cir. 1997), Rice v. Harkin 

Exploration Company, 250 F.3d 264 (5th Cir. 2001), and U.S. v. Needham, No. 02-

30217,2003 WL 22953383 (5th Cir. 2003).) (p. 5)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries. Section I of the Technical Support Document provides 

a discussion of the legal basis of the final rule, including consistency with the statute 

and Supreme Court decisions.

North American Meat Association and American Meat Institute (Doc. #13071)

8.275 The proposed rule would contribute to the confusion by including wetlands, lakes, and 

ponds as tributaries, even when they have no bed, bank; and OHWM. Specifically, the 

proposed rule provides "waters, including wetlands that are adjacent to a wetland that 

meets the definition of tributary would be considered adjacent waters."18 This language 

collapses and confuses the "adjacent wetlands" and "tributary" categories of jurisdiction. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

444

Such inclusion conflicts with how tributaries are traditionally defined in scientific 

literature.498 (p. 6)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries. 

Kennewick Irrigation District, Kennewick, Washington (Doc. #13571)

8.276 This definition is troublesome, as it would appear to expand what constitutes "waters of 

the United States" to include irrigation and on-farm drainage features such as canals, 

ditches, ponds, and wetlands created by irrigation seepage. (p. 4)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries. Paragraph (b) of the final rule provides exclusions for 

many features, including but not limited to most ditches that are not relocated 

tributaries or excavated in a tributary, artificial lakes and ponds created in dry land 

and used primarily for uses such as stock watering, irrigation, etc. and artificially 

irrigated areas that would revert to dry land should application of water to that 

area cease.

American Exploration & Mining Association (Doc. #13616)

8.277 The Definition of “Tributary” Will Result in Duplicative and Onerous Permit 

Requirements.

The proposed rule categorically determines that tributaries have a significant nexus to 

traditional navigable waters, interstate waters, and the territorial seas. 79 Fed. Reg. at 

22,201. Likewise, waters and wetlands adjacent to tributaries will be automatically 

jurisdictional. Id. at 22,263. Any channelized feature, including ditches and other manmade conveyances, no matter how remote from navigable waters, will be jurisdictional 

tributaries if they exhibit a bed, bank and ordinary high water mark. The proposed rule’s 

“tributary” definition vastly expands the scope of features that are currently regulated as 

tributaries, extending jurisdiction to features like ephemeral drainages and stormwater 

conveyances that have not been and should not be jurisdictional. (p. 4)

Agency Response: Section I of the Technical Support Document discusses the 

historic scope of the regulatory definition of “waters of the United States,” and also 

provides a broader discussion of the legal basis of the final rule, including 

consistency with the statute and Supreme Court decisions. Section IV(I) of the 

preamble to the final rule and the summary responses in Compendium 7 of this 

RTC, “Features and Waters Not Jurisdictional,” provide a broad discussion of the 

final rule’s exclusions, including those for stormwater control features created in 

dry land. See summary response for section 6.2, “Excluded Ditches” in this RTC 

for a more focused discussion of revised and clarified ditch exclusions. The agencies 

believe that these exclusions ensure for the first time by rule that most ditches will 

 

498 See SAB Panel Comments on Proposed Rule, at 2.
Clean Water Rule Response to Comments – Topic 8: Tributaries

445

not be considered waters of the United States. The final rule is consistent with the 

agencies’ longstanding interpretation of the CWA that a tributary can be a natural, 

man-altered, or man-made water. Section IV(F) of the preamble to the final rule 

and section VII of the Technical Support Document discuss tributaries, including 

man-made or man-altered tributaries. See also the summary response for 

“Relevance of Flow Regime” in section 8.1.1 above, particularly the subsection on

“Regulation of Man-Altered Streams” and the summary response for section 8.2 

above, “Ditches as Tributary.” As defined in the final rule, “tributaries” thus 

include waters such as rivers, streams, canals, and ditches not excluded under 

paragraph (b). The agencies’ position in regard to tributaries is rooted in a sciencebased conclusion that such waters have a significant nexus either individually or in 

the aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion.

Western Growers Association (Doc. #14130)

8.278 Western Growers asks that the Corps and EPA clarify several aspects of “tributaries”...

...the proposed regulation also appears to create two kinds of tributaries: 1) smaller 

waterways that have a bed, banks, and ordinary high water mark; and 2) waters like lakes, 

wetlands, and ponds that lack these features but nevertheless contribute flow to 

traditional as jurisdictional waters.499 The division between these two types of 

“tributaries” is unclear, particularly because many lakes can have a bed, banks, and high 

water mark. It is our belief that the categorization of lakes and ponds as “tributaries” 

requires additional clarification. As one example of the potential ambiguity, is a lake with 

a bed, banks, and high water mark a “water ‘‘waters of the United States” if it flows into 

a non-navigable stream that flows into an impoundment of a navigable-in-fact waterway? 

(p. 13)

Agency Response: The definition of “tributary” has been clarified in the final 

rule, and no longer includes ponds, lakes, and wetlands as tributaries. Section I of 

the Technical Support Document discusses legal basis of the final rule, including 

consistency with the statute and Supreme Court decisions. The agencies’ position in 

regard to tributaries is rooted in a science-based conclusion that such waters have a 

significant nexus either individually or in the aggregate with traditional navigable 

waters, interstate waters, and the territorial seas. Section VII of the Technical 

Support Document discusses the science supporting the agencies’ conclusion.

National Corn Growers Association (Doc. #14968)

8.279 ...we think it is unlawful for any of the following to be deemed WOTUS categorically:

...

 

499 “II.F.1 What is a Tributary for the purposes of the proposed regulation?” 79 Fed. Reg. 22,188, 22,201-04 (April 

21, 2014).
Clean Water Rule Response to Comments – Topic 8: Tributaries

446

2. Impoundments of Ephemeral or Intermittent Tributaries. Only impoundments of 

WOTUS should be found to themselves be categorically WOTUS. Such impoundments 

could be found to be WOTUS on a case-States’’ by-case basis. But as in the case for 

ephemeral or intermittent or tributaries, to do so categorically without accounting for the 

specific facts involving the affected flows is not lawful as it would amount to speculation.

3. Wetlands or Waters that are Adjacent to Ephemeral Intermittent Tributaries or 

their Impoundments. Only waters that are adjacent to WOTUS could be found to be 

WOTUS, and since ephemeral and intermittent tributaries and their impoundments 

should not be found WOTUS categorically, neither should wetlands nor waters adjacent 

to them be so categorically found.

... (p. 20, 21)

Agency Response: The agencies agree that only impoundments of waters of the 

United States should categorically themselves be waters of the United States, and 

this is clearly the meaning of paragraph (a)(4) of the final rule. Section IV(G) of the 

preamble and section VIII of the Technical Support Document discuss “adjacent 

waters.” The agencies’ position in regard to tributaries is rooted in a science-based 

conclusion that such waters have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion and are thus, waters of the United States. The 

definition of “tributary” has been clarified in the final rule, and no longer includes 

ponds, lakes, and wetlands as tributaries. 

Klamath Water Users Association (Doc. #15063)

8.280 ...Wetlands should not be considered “tributaries” in the final rule, as they should have to 

meet the “adjacent” and “significant nexus” tests to be considered “waters of the U.S.” 

(p. 5)

Agency Response: The definition of “tributary” has been clarified in the final 

rule, and no longer includes ponds, lakes, and wetlands as tributaries. 

Union County Cattlemen (Doc. #15261)

8.281 FR Page Page 22206 (6) Man-Made or Man-Altered Tributaries Significantly Affect the 

Chemical, Physical, and Biological Integrity of(a)(l) Through (a)(3) Waters This 

proposal expressly states that a tributary, including wetlands, can be a natural, manaltered, or man-made water body and includes waters such as rivers, streams, lakes, 

impoundments, canals, and ditches that meet the definition of tributary and are not 

excluded from the definition of "waters of the United States" by paragraphs (b)(3) and 

(b)(4) of the proposed rule.

Comment: We disagree. Man-altered water bodies do not require EPA's oversight or 

regulatory actions. Water quality sampling by inspectors for so many water areas is 

beyond the agencies' ability to conduct the work in a reasonable manner. Tributaries and 

wetlands are very distinct in much of the West and many have limited water, do not 

contribute sediments to a flowing body of water, and are being managed and observed at 

the state and local levels of government. A man-made ditch is man-made for many 
Clean Water Rule Response to Comments – Topic 8: Tributaries

447

reasons unrelated to the authority provided in the CWA. It has nothing to do with the 

CWA and the agencies should delete references to man-made conveyances. There is little 

or no evidence that they impact any flowing water body directly or indirectly to an extent 

that the contributions from runoff or anthropogenic activities create pollution problems. 

Delete this section.

EPA's desire to re-write the Supreme Court opinions and traditional use of the term 

"navigable waters" appears to be a grab at authority the people of the United States have 

not given to the agency in the law. If and when we do desire the agency to regulate more 

we will go through Congress to give the agencies the amount and kind of regulatory 

authority that will be workable and beneficial to everyone. (p. 3)

Agency Response: The agencies disagree. The final rule is consistent with the 

agencies’ longstanding interpretation of the CWA that a tributary can be a natural, 

man-altered, or man-made water. Section IV(F) of the preamble to the final rule 

and section VII of the Technical Support Document discuss tributaries, including 

man-made or man-altered tributaries. See also the summary response for 

“Relevance of Flow Regime” in section 8.1.1 above, particularly the subsection on

“Regulation of Man-Altered Streams” and the summary response for section 8.2 

above, “Ditches as Tributary.” Section I of the Technical Support Document 

discusses legal basis of the final rule, including consistency with the statute and 

Supreme Court decisions.

8.282 FR Page Page 22206 As described above, tributaries of all flow regimes have a 

significant nexus to downstream (a)(l) through (a)(3) waters. Due to the often 

straightened and channelized nature of ditches, these tributaries quickly move water 

downstream to (a)(l) through (a)(3) waters. Ditches and canals, like other tributaries, 

export sediment, nutrients, and other materials downstream.

Comment: We disagree. We are unaware of the science that supports such notions as the 

export of sediment, nutrients, and other materials downstream. Delete this because it is 

too broad in the approach field-testing has taken place and been conducted in a way to 

associate the channelized ditches to the nutrients and sediments contributed to the 

"navigable waters". Delete the references to "materials" if you cannot describe what the 

materials might be that are harmful to the water. (p. 3-4)

Agency Response: The agencies disagree. The final rule is consistent with the 

agencies’ longstanding interpretation of the CWA that a tributary can be a natural, 

man-altered, or man-made water. Section IV(F) of the preamble to the final rule 

and section VII of the Technical Support Document discuss tributaries, including 

man-made or man-altered tributaries. See also the summary response for 

“Relevance of Flow Regime” in section 8.1.1 above, particularly the subsection on

“Regulation of Man-Altered Streams” and the summary response for section 8.2 

above, “Ditches as Tributary.”

Beet Sugar Development Foundation (Doc. #15368)

8.283 a. Defining Tributaries and Wetlands as per se “Waters of the United States”
Clean Water Rule Response to Comments – Topic 8: Tributaries

448

BSDF recommends that the agencies implement the alternative approach to defining 

tributaries that flow through wetlands as “waters of the United States.”500 BSDF agrees 

that including wetlands within the definition of tributary will add confusion because the 

wetlands have no ordinary high water mark. Both wetlands and tributaries should be 

analyzed under their respective categories. (p. 16)

Agency Response: The definition of “tributary” has been clarified in the final 

rule, and no longer includes ponds, lakes, and wetlands as tributaries.

Jensen Livestock and Land LLC (Doc. #15540)

8.284 The proposed rule states “...ditches not excluded in section (b) that, either directly or 

through other tributaries, convey water to...” Yet, this is in conflict with the actual 

definition for a tributary that states “...which contributes flow, either directly or through 

another water,...”501 It is unclear whether to be a tributary the feature must contribute 

water through any means (i.e. “another water”) or through another tributary. Contributing 

flow through any type of water is clearly expansive, essentially making anything with a 

bed, bank and OHWM a “tributary” and subject to the CWA. It also contradicts the 

agencies’ statements and proposition that the proposed definition does not regulate 

groundwater, if groundwater can serve as the connection, and part of, a “tributary.” 

Jensen Livestock and Land LLC. assert that neither Congress nor the Commerce Clause 

of Article I of the U.S. Constitution intended or allows such a result.502 The agencies’ 

definition of “tributary” violates the CWA and is beyond the authority of Congress to 

grant such unlimited authority based on the restrictions under the Commerce Clause of 

the U.S. Constitution. (p. 11)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries. Although revised, the definition of “tributary” retains 

the requirement that a water contribute flow, either directly or through another 

water (including an impoundment identified in paragraph (a)(4) of the final rule), to 

a water identified in paragraphs (a)(1) through (3) of the final rule and also possess 

physical indicators of a bed and banks and an ordinary high water mark in order to 

be considered a water of the United States as a “tributary.” Groundwater is 

explicitly excluded as water of the United States in paragraph (b) of the final rule.

8.285 a. Ambiguous Terms and Phrases

Jensen Livestock and Land LLC assert that the vast instances of undefined terms and 

phrases throughout the proposed rule make meaningful comments on the proposed rule 

impossible. Jensen Livestock and Land LLC cannot provide comments on the impact of a 

proposed definition that does not exist, or has a wide range of interpretations. This 

 

500 See Definition of “Waters of the United States” Under the Clean Water Act, 79 Fed. Reg. at 22203 (requesting 

comment on how to delineate tributaries from wetlands).

501 Proposed Rule at 22202.

502 SWANCC at 173; (“...we have reaffirmed the proposition that the grant of authority to Congress under the

Commerce Clause, though broad, is not unlimited...But this [Migratory Bird Rule] is a far cry, indeed, from the

‘navigable waters’ and ‘waters of the United States’ to which the statute by its terms extends.”).
Clean Water Rule Response to Comments – Topic 8: Tributaries

449

section attempts to identify those legally important terms and phrases that the agencies 

have failed to adequately describe. However, Jensen Livestock and Land LLC assert that 

unless the agencies re-propose the definition with adequately defined terms and phrases 

for these legally significant terms that the public can comment on, they have not satisfied 

the notice and comment requirements under the APA.

...

iii. “Through Another Water”

Under the definition for tributary as well as the exclusions for ditches the agencies have 

used the phrase “through another water.” (Proposed Rule at 22199). Yet, the agencies 

have neglected to explain what this phrase means. When an important regulatory term or 

phrase is left undefined the regulated community will look at the broadest logical 

meaning of the term or phrase to determine the scope of their liability. In this case the 

phrase “through another water” could mean through ground water or through a nonjurisdictional ditch. If the agency does find that a ditch lacks a surface water connection 

to any other jurisdictional water, but does have some groundwater connection to a 

jurisdictional water, that water can now fall outside the exclusions for ditches, and now is 

a tributary by rule.

Jensen Livestock and Land LLC believe that the agencies should have known they 

needed to provide a definition for such significant regulatory terms, and their failure to 

provide a definition prohibits Jensen Livestock and Land LLC. from being able to 

meaningfully comment on the proposed rule. The agencies must re-propose the rule with 

such definitions included so that the regulated public may provide comments on its scope. 

Jensen Livestock and Land LLC. assert that including groundwater in the phrase 

“through another water” is inappropriate and fails to recognize that there is a limit to 

federal jurisdiction under the CWA. (p. 16-17)

Agency Response: The proposed rule preamble included language explaining the 

terms water and waterbodies as the agencies used them in the proposal. The public 

had ample opportunity to comment on these terms. Section IV(F) of the preamble 

to the final rule discusses “tributaries,” including the phrase “through another 

water.” See summary response. See also summary response 13.2.1 for a discussion 

of compliance with the APA. 

Florida Crystals Corporation (Doc. #16652)

8.286 The Proposed Rule would now regulate most Florida farm ditches. The Proposed Rule 

would define the "navigable waters" to include "all tributaries" of waters used in 

interstate or foreign commerce and the territorial seas. A "tributary" is defined as "a water 

physically characterized by the presence of a bed and banks and ordinary high water 

mark ... which contributes flow, either direct or through another water, to [waters used in 

interstate or foreign commerce, interstate waters, the territorial seas, and impoundments 

of such waters]." Since almost all ditches in Florida are connected to offsite waters of 

some sort in order to provide drainage and irrigation functions, and eventually connect to 

the ocean through circuitous routes, the Proposed Rule makes almost all ditches 

presumptively subject to federal regulation under the CWA. (p. 4)
Clean Water Rule Response to Comments – Topic 8: Tributaries

450

Agency Response: The summary response in Section 6.2 of the Ditches 

compendium in this RTC discusses how the proposed exclusions for ditches were 

edited and clarified for the final rule. The agencies believe that these exclusions 

ensure for the first time by rule that most ditches will not be considered waters of 

the United States.

North Dakota Farmers Union (Doc. #16930.1)

8.287 “Wetland” as a “Tributary”

We are particularly concerned about including “wetlands” in the definition of tributaries. 

Wetlands are not tributaries under any legal, plain language, or common sense 

understanding. If a discharge into a wetland is significantly affecting a navigable water, it 

will be jurisdictional as an “adjacent water” or significant nexus analysis of “other 

waters.” Further, finding jurisdiction over the wetland as a tributary will only further 

confuse – not provide clarity to – farmer and rancher community.

Recommendation: We strongly request that “wetlands” are removed from any definition 

of tributary. (p. 4)

Agency Response: See the summary responses for Sections 8.1 and 8.2. 

Agribusiness Association of Kentucky et al. (Doc. #18005)

8.288 Given the breadth of the definitions in the proposed rule, the vast majority of ephemeral 

drainage features and ditches on farmlands and pastures described above would be 

categorically regulated as jurisdictional tributaries under the proposed rule. And the vast 

majority of small wetlands, ponds and pools (including, potentially, ephemeral ponds, 

which some might call "puddles") would be either categorically regulated as "adjacent" 

waters or could still be regulated as "other waters." Consequently, with the exception of 

very narrow section 404 exemptions discussed in Part IV.A below, regulating drains, 

ditches, stock ponds, and other low spots within farm fields and pastures as "navigable 

waters" would mean that any discharge of a pollutant (e.g., soil, dust, pesticides, 

fertilizers and "biological material") into those ditches, drains, ponds, etc. will be 

unlawful without a CWA permit. (p. 2-3)

Agency Response: Puddles and ephemeral drainage features that do not meet the 

revised definition of “tributary” in the final rule and are both explicitly excluded 

from being considered waters of the United States in paragraph (b)(4) of the final 

rule. In addition, artificial lakes and ponds created in dry land and used primarily 

for uses such as stock watering, irrigation, etc. are also excluded under paragraph 

(b)(4). Section IV(I) of the preamble to the final rule and the summary responses in 

Compendium 7 of this RTC, “Features and Waters Not Jurisdictional,” provide a 

broad discussion of the final rule’s exclusions. See summary response for section 

6.2, “Excluded Ditches” in this RTC for a more focused discussion of revised and 

clarified ditch exclusions. The agencies believe that these exclusions ensure for the 

first time by rule that most ditches will not be considered waters of the United 

States.

8.289 In their marketing campaign, the Agencies repeatedly insist that the rule does not expand 

jurisdiction over ditches, that most ditches will not be regulated, that ditches are 
Clean Water Rule Response to Comments – Topic 8: Tributaries

451

excluded, and that the Agencies do not intend to regulate ditches.503 A careful reading of 

the proposal's fine print, combined with a common sense understanding of ditches and 

how they function, however, shows that the proposed rule would in fact regulate many 

ditches. (At the very least, the proposed language could easily be interpreted to regulate 

many ditches, and we presume that, like most EPA/Corps regulations, it would be 

broadly interpreted by the Agencies.) Lost in the denials is the fact that, for the first time 

ever, the text of the Agencies' regulations will specifically define the term "tributary" to 

include "ditches" and "canals." The proposed rule would categorically regulate as 

"tributaries" all ditches that ever carry any amount of water that eventually flows (over 

any distance and through any number of other ditches) to a navigable water—unless the 

ditch falls within a narrowly crafted exclusion for certain "upland" ditches. (p. 8-9) 

Agency Response: The summary response in Section 6.2 of the Ditches 

compendium in this RTC discusses how the proposed exclusions for ditches were 

edited and clarified for the final rule. The agencies believe that these exclusions 

ensure for the first time by rule that most ditches will not be considered waters of 

the United States. 

Hampton Roads Planning District Commission, Chesapeake, Virginia (Doc. #9612)

8.290 The definition of tributaries should not include features such as wetlands, lakes, 

ponds, impoundments or ditches. It would be more appropriate to classify these 

features as "other waters" which would require a case-specific significant nexus analysis 

to determine if they are WOTUS. (p. 2)

Agency Response: See the summary responses for Sections 8.1 and 8.2. 

Georgia Department of Transportation (Doc. #14282.1)

8.291 C. Relationship to exclusions for ditches

The definition of "tributary" in the proposed rule includes "ditches not excluded in 

paragraph (b)(3) or(4) of this section." We interpret this statement to mean that, if a ditch 

is excluded by paragraphs (b)(3)or (b)(4), the ditch cannot be considered jurisdictional, 

even if it would otherwise meet the definition of "tributary."

Recommendation: The final rule should make clear that the exclusions take precedence 

over the jurisdictional-by-rule provisions. We raise this concern because of the breadth of 

the definition of "tributary" in the proposed rule. If that definition is not changed, it is 

possible that some ditches could meet the criteria for being jurisdictional by rule, while 

also meeting the criteria for the first ditch exclusion - i.e., "excavated wholly in uplands, 

drain only uplands, and have less than perennial flow." The final rule should clearly state 

that, in those situations, the exclusion takes precedence and therefore the ditch would be 

deemed non-jurisdictional. (p. 6)

Agency Response: Paragraph (b) of the final rule clearly states that the excluded 

features identified therein “are not waters of the United States even where they 

 

503 U.S. EPA, "Facts About the Waters of the U.S. Proposal", July 1, 2014, 

http://www2.epa.gov/sites/productionlfiles/2014-09/documents/facts_about_wotus.pdf and attached at Appendix H.
Clean Water Rule Response to Comments – Topic 8: Tributaries

452

otherwise meet the terms of paragraphs (a)(1) through (a)(8)” of the rule. Thus, 

neither an excluded ditch nor any other excluded feature may be considered waters 

of the United States under any other provision of the rule. 

Department of Public Works, City of Chesapeake, Virginia (Doc. #5612.1)

8.292 The Rule proposes to categorize wetlands, lakes, ponds, impoundments and ditches as 

tributaries, even if they lack a bed and banks or Ordinary High Water Mark (OHWM), if 

they contribute flow to WOUS, regardless of perennial, intermittent or ephemeral flow; 

therefore, by Rule, these features would be jurisdictional WOUS without any significant 

nexus analysis. The City does not support a definition of tributaries to include features 

such as wetlands, lakes, ponds, impoundments or ditches. It would also not be 

appropriate to evaluate these features as adjacent waters, resulting in jurisdictional 

determinations without any significant nexus analysis; however, it may be appropriate to 

evaluate these features through a case-specific significant nexus analysis as "other 

waters." (p. 2)

Agency Response: See the summary responses for Sections 8.1 and 8.2. The 

agencies disagree that wetlands, lakes, ponds and- impoundments should not be 

regulated as adjacent waters. See section IV(G) of the preamble to the final rule 

and section VIII of the Technical Support Document for discussions concerning 

adjacent waters.

8.293 The Rule states that a tributary is a WOUS, and a tributary may be ephemeral, 

intermittent or perennial. This statement is in direct conflict with the exemption for 

ditches that have less than perennial flow. Ephemeral and intermittent ditches are not 

tributaries and should not be subject to regulatory oversight under the CWA. The Corps' 

Nationwide Permit program defines an ephemeral stream having flowing water only 

during, and/or a short duration after, precipitation events in a typical year; in addition, 

ephemeral stream beds are located above the water table year-round and groundwater is 

not a source of water/or the stream... Ephemeral streams as well as ditches with less than 

perennial flow should be explicitly exempt to regulatory oversight under the CWA. (p. 3)

Agency Response: The agencies disagree that the exclusions for ditches is in direct 

conflict with the definition of “tributary.” First, the exclusions for ditches have 

been revised and clarified in the final rule (see Section 6.2 of the Ditches 

compendium of this RTC). Second, paragraph (b) of the final rule clearly states 

that the excluded features identified therein, including ditches, “are not waters of 

the United States even where they otherwise meet the terms of paragraphs (a)(1) 

through (a)(8)” of the rule. Thus, neither an excluded ditch nor any other excluded 

feature may be considered waters of the United States under any other provision of 

the rule. The agencies also disagree that ephemeral streams should not be 

considered waters of the United States. See summary response for “Relevance of 

Flow Regime” in section 8.1.1 of this RTC, particularly subsections on jurisdiction 

over intermittent and ephemeral waters and the legality of asserting jurisdiction 

over ephemeral waters. The agencies’ position in regard to tributaries is rooted in a 

science-based conclusion that such waters have a significant nexus either 

individually or in the aggregate with traditional navigable waters, interstate waters, 
Clean Water Rule Response to Comments – Topic 8: Tributaries

453

and the territorial seas. Section VII of the Technical Support Document discusses 

the science supporting the agencies’ conclusion.

Black Hills Corporation (Doc. #6248)

8.294 "Tributaries" - The draft definition of "tributary" includes any feature that drains to U.S. 

water bodies and has a bed, bank and an ordinary high water mark. A tributary can be 

natural, man-altered, or man-made, and include rivers, streams, lakes, impoundments, 

canals, and man-made ditches and conveyances. This definition covers most types of 

manmade surface structures to manage water flow and treatment including roadside 

ditches, ditches associated with treatment systems, stormwater management conveyances, 

and irrigation ditches. (p. 3)

Agency Response: See the summary responses for Sections 8.1 and 8.2. 

Paragraph (b) of the final rule provides many exclusions, including but not limited 

to waste treatment systems designed to meet the requirements of the CWA, most 

ditches that are not relocated tributaries or excavated in a tributary, stormwater 

control features constructed in dry land, and artificial lakes and ponds created in 

dry land and used primarily for uses such as stock watering, irrigation, etc. Section 

IV(I) of the preamble to the final rule and the summary responses in Compendium 7

of this RTC, “Features and Waters Not Jurisdictional,” provide a broad discussion 

of the final rule’s exclusions. See summary response for section 6.2, “Excluded 

Ditches” in this RTC for a more focused discussion of revised and clarified ditch 

exclusions. The agencies believe that these exclusions ensure for the first time by 

rule that most ditches will not be considered waters of the United States.

Clearwater Watershed District et al. (Doc. #9560.1)

8.295 Wetlands are not understood as tributaries in either common sense, plain language or in 

statutory and caselaw verbage. It is not logical to refer to a wetland, a body of water 

without a defined bed, bank, and ordinary high water mark, as a "tributary."

... the agencies inclusion of wetlands as tributaries is contradictory to its analysis of 

adjacent wetlands within the proposed rule. Under the agencies analysis of adjacent 

waters, the agencies state, "In circumstances where a particular water body is outside of 

the floodplain and riparian area of a tributary, but is connected by a shallow subsurface 

hydrologic connection or confined surface hydrologic connection with such tributary, the 

agencies will also assess the distance between the water body and tributary in 

determining whether or not the water body is adjacent." In the case of a wetland 

connected by a confined surface hydrologic connection, a reasonable interpretation of the 

proposed rule would conclude that all such wetlands would be tributaries due to their 

outlet connection. Therefore, no wetland would be outside of reasonable proximity to 

other waters of the United States as they would all be considered tributaries themselves.

RECOMMENDATION: We recommend that the agencies do not consider wetlands as 

tributaries under the new rule. We support jurisdiction over wetlands that are adjacent to 

navigable waters, interstate waters, or the territorial seas. We support the clarity of a rule 

that defines adjacent as "neighboring" and limits the interpretation of neighboring to only 

those wetlands that have a confined surface hydrologic connection within a reasonable 

proximity to navigable waters. (p. 11)
Clean Water Rule Response to Comments – Topic 8: Tributaries

454

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries. Section (IV)(G) of the preamble and section VIII of the 

Technical Support Document discuss “adjacent waters.”

Central Massachusetts Regional Stormwater Coalition (Doc. #15443.1)

8.296 The definition of the term “tributary” in this section of the Proposed Rule includes 

wetlands. The term “tributary” is commonly considered to mean moving water and could 

result in confusion for entities regulated under the MS4 Program. Headwater wetlands are 

already classified as “adjacent” under §328.3(c)(1), and many categories of wetlands are 

thoroughly defined, regulated, and managed in Massachusetts under the Wetlands 

Protection Act (310 CMR 10.00). This duplication and contradiction in the Proposed 

Rule introduces the very confusion that it aims to eliminate. We suggest that the clause 

“including wetlands” be removed from the last sentence in this section. (p. 2)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries.

Duke Energy (Doc. #13029)

8.297 Tributaries: The definition for tributaries should be reexamined and several key changes 

should be made:

 Remove language that would include lentic-type waters (lakes, ponds, wetlands, 

impoundments) from this category as they would be better classified under 

different categories;

 Remove the explicit references to ditches from the definition... (p. 12)

Agency Response: See the summary responses for Sections 8.1 and 8.2. Although 

the exclusions for ditches have been revised and clarified in the final rule (see 

Section 6.2 of the Ditches compendium of this RTC), thus ensuring for the first time 

by rule that most ditches will not be considered waters of the United States, the 

agencies believe that some ditches do serve as tributaries and provide many of the 

same functions to downstream waters as natural tributaries. See summary response 

for section 8.2 above, particularly the subsection on “Ditches as Tributary.” 

8.298 With this new overly broad definition, the agencies would extend jurisdiction to many 

water features that the agencies have not historically regulated, such as ephemeral 

streams, and the proposed definition specifically identifies ditches as tributaries. (p. 21)

Agency Response: The agencies disagree that ephemeral streams should not be 

considered waters of the United States. See summary response for “Relevance of 

Flow Regime” in section 8.1.1 of this RTC, particularly subsections on jurisdiction 

over intermittent and ephemeral waters and the legality of asserting jurisdiction 

over ephemeral waters. The agencies’ position in regard to tributaries is rooted in a 

science-based conclusion that such waters have a significant nexus either 

individually or in the aggregate with traditional navigable waters, interstate waters, 

and the territorial seas. Section VII of the Technical Support Document discusses 
Clean Water Rule Response to Comments – Topic 8: Tributaries

455

the science supporting the agencies’ conclusion. The exclusions for ditches have 

been revised and clarified in the final rule (see Section 6.2 of the Ditches 

compendium of this RTC), thus ensuring for the first time by rule that most ditches 

will not be considered waters of the United States. The agencies believe that some 

ditches do serve as tributaries and provide many of the same functions to 

downstream waters as natural tributaries. See summary response for section 8.2 

above, particularly the subsection on “Ditches as Tributary.”

8.299 The inclusion of water features that lack a bed, bank and OHWM such as wetlands, lakes 

or ponds also extends the concept of a tributary way past a traditional meaning and 

introduces additional confusion. These types of waters would be more appropriately 

covered under a different category such as “adjacent waters,” not defined as tributaries. 

(p. 23)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries.

8.300 Another aspect that is confusing with the definition of tributary concerns the inclusion of 

non-stream features that lack a bed, bank and OHWM, such as wetlands, lakes and ponds. 

Not only does this broaden the traditional meaning of a tributary, but it directly conflicts 

with how tributaries are defined in scientific literature.504 The agencies do not provide 

any clarification on how these types of water features would be different from “adjacent 

waters”. (p. 25)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries.

8.301 It is also unclear why impoundments are listed in the definition for tributary, when they 

are already included in their own category as an (a)(4) water under the definition for 

“waters of the United States.” Since the agencies did not propose a definition for 

impoundment, it leaves open the possibility that different impoundments could be 

regulated as an (a)(5) tributary versus and (a)(4) impoundment. Again, this does not 

provide the clarity the agencies claim and regulated stakeholders seek. (p. 25-26)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

impoundments and wetlands as tributaries.

Murray Energy Corporation (Doc. #13954)

8.302 The new definition of “tributary” in the Proposed Rule would also radically alter this 

term’s traditional meaning and long-held practice by extending the term to lakes, ponds 

and wetlands, even where they lack traditional indicia of tributary – i.e., OHWM and bed 

and bank. Provided the tributary “contribute[s] flow, either directly or through” (a)(1) to 

(a)(4) waters, no matter how significant or insignificant the flow is, under this Proposed 

Rule it will be deemed jurisdictional. Proposed Rule at 22272.

 

504 SAB Panel Comments on proposed rule, September 30, 2014, Page 2 (EPA-SAB-14-007).
Clean Water Rule Response to Comments – Topic 8: Tributaries

456

The Agencies’ proposed approach deeming all tributaries as per se jurisdictional is 

inconsistent with the Agencies’ desire for consistency, clarity and certainty to the extent 

the new definition of “tributary” includes wetlands and other water bodies that do not 

contain clear and discernible features such as bed and bank and OHWM. The definition is 

also at odds with the Agencies’ description of a tributary elsewhere in the Proposal, 

where the agencies seem to acknowledge the necessary presence of bed and bank and 

OHWM. (“A tributary is a longitudinal surface feature that results from directional 

surface water movement and sediment dynamics demonstrated by the presence of bed 

and banks, bottom and lateral boundaries, or other indicators of OHWM.”). Id. at 22202 

(emphasis added). (p. 10-11)

Agency Response: See the summary response for Section 8.2. The definition of 

“tributary” has been clarified in the final rule, and no longer includes ponds, lakes, 

and wetlands as tributaries.

8.303 Also troubling to us is the potential for significantly expanded jurisdiction over 

stormwater ditches and temporary diversion ditches under the current Proposal. If 

adopted as written, the broad new definition of “tributary” and narrow, if not 

meaningless, exclusions for ditches under the Proposed Rule would bring many, perhaps 

even most, stormwater ditches under federal jurisdiction. Specifically, the Proposed Rule 

would extend jurisdiction to all stormwater ditches with an identifiable bed, bank and 

OHWM that drain into “waters of the U.S.” Considering the Proposal’s expanded 

interpretation of “waters of the U.S.,” this would likely become an exceedingly common 

scenario, necessitating a substantial increase in the number of jurisdictional 

determinations and permit applications required at regulated sites across the country. (p. 

14)

Agency Response: Paragraph (b) of the final rule provides many exclusions, 

including but not limited to waste treatment systems designed to meet the 

requirements of the CWA, most ditches that are not relocated tributaries or 

excavated in a tributary and stormwater control features constructed in dry land. 

Section IV(I) of the preamble to the final rule and the summary responses in 

Compendium 7 of this RTC, “Features and Waters Not Jurisdictional,” provide a 

broad discussion of the final rule’s exclusions. See summary response for section 

6.2, “Excluded Ditches” in this RTC for a more focused discussion of revised and 

clarified ditch exclusions. The agencies believe that these exclusions ensure for the 

first time by rule that most ditches will not be considered waters of the United 

States.

Southern Company (Doc. #14134)

8.304 ...the upper limit of a tributary, according to the agencies, is usually established where 

“the channel begins,” but under the proposal, jurisdiction may extend farther up into a 

watershed if wetlands are providing flow to the tributary. (See Proposed Rule at 22201) 

(“wetlands, lakes and ponds are tributaries (even if they lack a bed and banks (sic) or 

ordinary high water mark) if they contribute flow, either directly or through another water 

to a water identified in paragraphs (a)(1) through (3).”). This could potentially extend 

jurisdiction well into upper reaches of watersheds and water features far from tributaries 

with discernible bed and bank and OHWM that were not otherwise jurisdictional prior to 
Clean Water Rule Response to Comments – Topic 8: Tributaries

457

the proposed rule, and regardless of a tributary’s significant nexus to TNWs.505 As a 

practical matter, it will be extremely difficult for the regulated community and the 

agencies to effectively determine—absent continuous flow—what features are upstream 

or downstream. For example, transmission lines are most frequently constructed on 

narrow rights-of-way, which provide very limited access to adjacent features and land. 

The agencies have not explained how they or the regulated community would gain access 

to wholly separate (and disinterested) tracks of land (up- and down-gradient) to assess 

whether on-site features “contribute flow.” (p. 35-36)

Agency Response: See the summary responses for Sections 8.1 and 8.2. 

Santa Clara Valley Water District, California (Doc. #14776)

8.305 The agencies' implicit suggestion that lakes and ponds may lack a bed and banks or 

ordinary high water mark (79 Fed. Reg. 22263) is confusing and troubling. Currently, the 

lateral boundary of waters of the United States, apart from wetlands, is the ordinary high 

water mark. (33 C.F.R. § 328.4.) Indeed, the agencies commonly determine both the 

existence and extent of a water of the United States, e.g., a stream, by ascertaining 

whether a feature exhibits an ordinary high water mark. They fail to explain the 

conflicting suggestion in the Proposed Rule that a feature may constitute a "lake" or 

"pond" and thus a water of the United States even if it lacks an ordinary high water mark. 

(p. 3)

Agency Response: See the summary responses for Sections 8.1 and 8.2. 

Nucor Corp. (Doc. #14963)

8.306 ...the Agencies propose to expand the definition of "tributary" and, except in some very 

limited circumstances, categorically extend jurisdiction to ephemeral and intermittent 

drainages, ditches and other conveyances. Under the proposed rule, a "tributary" is 

defined as including any feature with a bed and banks and ordinary high water mark that 

contributes flow to a TNW, interstate water or territorial sea. 79 Fed. Reg. 22263. Even 

more importantly, the proposed rule stretches the definition of tributary to include manaltered and man-made waters and expressly includes ditches. Id. In doing so, the 

proposed rule gives no weight to the limits placed on jurisdiction by the Plurality or 

Justice Kennedy. The proposed rule categorically defines ditches carrying any amount of 

water in any location as tributaries and, even more alarmingly, has no exclusion for the 

Plurality's clear statement that ditches used to convey stormwater are not "waters of the 

United States". (p. 9)

Agency Response: See the summary responses for Sections 8.1 and 8.2. The 

agencies disagree that ephemeral streams should not be considered waters of the 

United States. See summary response for “Relevance of Flow Regime” in section 

8.1.1 of this RTC, particularly subsections on jurisdiction over intermittent and 

ephemeral waters and the legality of asserting jurisdiction over ephemeral waters. 

 

505 See U.S. v. Robison, 505 F.3d 1208 (11th Cir. 2007) (concluding in a criminal matter that a perennial stream, 

with continuous uninterrupted flow, was not jurisdictional under the CWA where the government failed to establish 

a significant nexus).
Clean Water Rule Response to Comments – Topic 8: Tributaries

458

The agencies’ position in regard to tributaries is rooted in a science-based 

conclusion that such waters have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion. The exclusions for ditches have been revised 

and clarified in the final rule (see Section 6.2 of the Ditches compendium of this 

RTC), thus ensuring for the first time by rule that most ditches will not be 

considered waters of the United States. The final rule is consistent with the 

agencies’ longstanding interpretation of the CWA that a tributary can be a natural, 

man-altered, or man-made water. Section IV(F) of the preamble to the final rule 

and section VII of the Technical Support Document discuss tributaries, including 

man-made or man-altered tributaries. See also the summary response for 

“Relevance of Flow Regime” in section 8.1.1 above, particularly the subsection on

“Regulation of Man-Altered Streams” and the summary response for section 8.2 

above, “Ditches as Tributary.” Section I of the Technical Support Document 

discusses the legal basis of the final rule, including consistency with the statute and 

Supreme Court decisions. 

Colorado River Water Conservation District, Colorado (Doc. #15070)

8.307 ...the inclusion of man-made canals in the definition of tributary adds to the confusion 

surrounding specifically which man-made ditches and canals are jurisdictional. At a 

minimum, the rule should explicitly state that it does not alter Section 404 exemptions 

included in the Clean Water Act. (p. 2)

Agency Response: The exclusions for ditches have been revised and clarified in 

the final rule (see Section 6.2 of the Ditches compendium of this RTC), thus ensuring 

for the first time by rule that most ditches will not be considered waters of the 

United States. The final rule is consistent with the agencies’ longstanding 

interpretation of the CWA that a tributary can be a natural, man-altered, or manmade water. Section IV(F) of the preamble to the final rule and section VII of the 

Technical Support Document discuss tributaries, including man-made or manaltered tributaries. See also the summary response for “Relevance of Flow Regime” 

in section 8.1.1 above, particularly the subsection on “Regulation of Man-Altered 

Streams” and the summary response for section 8.2 above, “Ditches as Tributary.” 

All statutory exemptions in the CWA remain in effect and unchanged by the final 

rule.

Illinois Fertilizer & Chemical Association (Doc. #15129)

8.308 Ditches should be removed from the definition of tributary as this term is overly broad 

and means very different things across the country only generating more confusion. (p. 1)

Agency Response: The exclusions for ditches have been revised and clarified in 

the final rule (see Section 6.2 of the Ditches compendium of this RTC), thus ensuring 

for the first time by rule that most ditches will not be considered waters of the 

United States. The final rule is consistent with the agencies’ longstanding 

interpretation of the CWA that a tributary can be a natural, man-altered, or manmade water. Section IV(F) of the preamble to the final rule and section VII of the 
Clean Water Rule Response to Comments – Topic 8: Tributaries

459

Technical Support Document discuss tributaries, including man-made or manaltered tributaries. See also the summary response for “Relevance of Flow Regime” 

in section 8.1.1 above, particularly the subsection on “Regulation of Man-Altered 

Streams” and the summary response for section 8.2 above, “Ditches as Tributary.” 

Tri-State Generation and Transmission Association, Inc. (Doc. #16392)

8.309 The use of the tributary definition to encompass wetlands, lakes, and ponds is duplicative, 

as the impoundments, adjacent waters, and other waters (based on a significant nexus 

evaluation) already address these systems. (p. 5)

Agency Response: See the summary responses for Sections 8.1 and 8.2. 

Texas Water Development Board (Doc. #16563)

8.310 ...the proposed rule goes on to include wetlands, lakes, and ponds even if they lack a bed 

and banks or ordinary high water mark as tributaries. The determination is made on the 

basis of whether a water contributes flow rather than on proximity as discussed by the 

Court. The rule should be re-drafted to consider only relatively permanent tributaries, and 

provide objective steps to determine connectivity based on a continuous surface 

connection to jurisdictional waters. (p. 6)

Agency Response: See the summary responses for Sections 8.1 and 8.2. Although 

excluded as “tributaries” in the final rule, the wetlands described by the commenter 

may still be waters of the United States if they meet the definition of “adjacent 

waters.” Section (IV)(G) of the preamble and section VIII of the Technical Support 

Document discuss “adjacent waters.” The exclusions for ditches have been revised 

and clarified in the final rule (see Section 6.2 of the Ditches compendium of this 

RTC), thus ensuring for the first time by rule that most ditches will not be 

considered waters of the United States. The final rule is consistent with the 

agencies’ longstanding interpretation of the CWA that a tributary can be a natural, 

man-altered, or man-made water. Section IV(F) of the preamble to the final rule 

and section VII of the Technical Support Document discuss tributaries, including 

man-made or man-altered tributaries. See also the summary response for 

“Relevance of Flow Regime” in section 8.1.1 above, particularly the subsection on 

“Regulation of Man-Altered Streams” and the summary response for section 8.2 

above, “Ditches as Tributary.” 

Ducks Unlimited (Doc. #11014)

8.311 In cases in which wetlands serve as water sources at the upper limit of the tributary 

system, or serve to connect two waters from among the other classes of wetlands 

considered jurisdictional by rule, we agree with the proposed approach of considering 

such wetlands as a "tributary" for purposes related to jurisdiction. The alternative 

approach of considering them "adjacent wetlands" would appear to achieve the same end 

result, but the proposed approach seems more efficient, particularly when considering the 

issue of classification of these waters for purposes of potential future database 

management. (p. 14)
Clean Water Rule Response to Comments – Topic 8: Tributaries

460

Agency Response: See the summary responses for Sections 8.1 and 8.2. Although 

excluded as “tributaries” in the final rule, the wetlands described by the commenter

may still be waters of the United States if they meet the definition of “adjacent 

waters.” Section (IV)(G) of the preamble and section VIII of the Technical Support 

Document discuss “adjacent waters.”

8.312 Treatment of "Ditches" Within the Tributary Class: In general, we find the EPA's 

treatment of ditches scientifically sound and acceptable. For example, it is clear that a 

significant nexus to other jurisdictional waters would be provided by the four primary 

types of ditches that would remain jurisdictional by rule: 

 natural streams that have been altered (e.g., channelized, straightened or 

relocated);

 ditches that have been excavated in "waters of the United States," including 

jurisdictional wetlands;

 ditches that have perennial flow; and,

 ditches that connect two or more "waters of the United States." (p. 14)

Agency Response: The exclusions for ditches have been revised and clarified in 

the final rule (see Section 6.2 of the Ditches compendium of this RTC). Ditches that 

meet the definition of “tributary” in the final rule and are not excluded under 

paragraph (b), will be considered waters of the United States as tributaries.

8.313 ... it should be made more clear that the treatment of ditches will not and cannot be used 

to expand the longstanding interpretation of jurisdiction as it applies to infrastructure 

used for normal agricultural activities... (p. 75)

Agency Response: Exclusions in paragraph (b) of the final rule include prior 

converted cropland, most ditches that are not relocated tributaries or excavated in a 

tributary, artificial lakes and ponds created in dry land and used for uses such as 

stock watering, irrigation, etc. and artificially irrigated areas that would revert to 

dry land should application of water to that area cease. Section IV(I) of the 

preamble to the final rule and the summary responses in Compendium 7 of this 

RTC, “Features and Waters Not Jurisdictional,” provide a broad discussion of the 

final rule’s exclusions. See summary response for section 6.2, “Excluded Ditches” in 

this RTC for a more focused discussion of revised and clarified ditch exclusions. 

Furthermore, all statutory exemptions, including those for normal farming, 

silviculture and ranching activities, remain in effect and unchanged by the final 

rule.

Southern Environmental Law Center et al. (Doc. #13610)

8.314 H. The definition of the term “tributaries” is confusing.

The term “tributaries” should be redefined so that it is clear that for the purposes of this 

rule wetlands, lakes, and ponds that contribute flow to a tributary system are clearly 

included in the term and thus do not require case-by-case jurisdictional analysis. (p. 4)

Agency Response: See the summary response for Section 8.2. In response to 

many public comments that found the proposed definition confusing, the definition 
Clean Water Rule Response to Comments – Topic 8: Tributaries

461

of “tributary” has been clarified in the final rule, and no longer includes ponds, 

lakes, and wetlands as tributaries. The wetlands described by the commenter may 

still be waters of the United States if they meet the definition of “adjacent waters.” 

Section (IV)(G) of the preamble and section VIII of the Technical Support 

Document discuss “adjacent waters.”

8.315 Comment: Under the proposed rule most ditches are considered tributaries. We offer the

following comments concerning ditches. In contrast to other tributaries, ditches are 

required to meet additional characteristics before even being potentially considered 

jurisdictional. Ditches must have an OHWM, connect directly or indirectly to a 

traditional navigable water or interstate water and meet one of five other factors, and the 

proposed Guidance presumes that ditches are not tributaries.506 Historically, ditches 

commonly have been protected under the CWA. Some so called ditches have been 

regulated under the Clean Water Act because they are actually altered streams (i.e., 

streams that have been dredged out), and because ditches can transport pollutants

downstream they are functionally no different than other tributaries. Ditches can also be

regulated under the Clean Water Act if they flow into other bodies of water that are 

protected by the Clean Water Act even if the ditches themselves are artificial.507 There is 

no compelling legal or scientific reason to treat ditches differently from other tributaries 

and find them jurisdictional under the significant nexus test and we urge EPA to remove 

the unnecessary and burdensome additional factors. (p. 48-49)

Agency Response: The exclusions for ditches have been revised and clarified in 

the final rule (see Section 6.2 of the Ditches compendium of this RTC). Ditches that 

meet the definition of “tributary” in the final rule and are not excluded under 

paragraph (b), will be considered waters of the United States as tributaries. The 

final rule is consistent with the agencies’ longstanding interpretation of the CWA 

that a tributary can be a natural, man-altered, or man-made water. Section IV(F) 

of the preamble to the final rule and section VII of the Technical Support Document 

discuss tributaries, including man-made or man-altered tributaries. See also the 

summary response for “Relevance of Flow Regime” in section 8.1.1 above, 

particularly the subsection on “Regulation of Man-Altered Streams” and the 

summary response for section 8.2 above, “Ditches as Tributary.”

Chesapeake Bay Foundation (Doc. #14620)

8.316 ii. CBF supports the inclusion of “Lakes, ponds and wetlands with surface connection to 

waters” in the definition of “Tributary”. CBF has considerable experience within bay 

states where nutrient pollution from lakes, ponds, canals, and ditches, because of higher 

residence times than streams or tidal waters, contributes to excessive microalgae 

populations and in some cases, harmful algal blooms. For example, Higgins Millpond, an 

 

506 Proposed Guidance, p.12.

507 Headwaters, Inc. v. Talent Irrigation Dist., 243 F.3d 526 (9th Cir. 2001); United States v. Holland, 373 F. Supp.

665 (M.D. Fla. 1974).
Clean Water Rule Response to Comments – Topic 8: Tributaries

462

artificially impounded tributary of the Transquaking River has experienced several 

harmful algal blooms which then spread beyond the confines of the impoundment.508

These conditions in turn can contaminate downstream water segments with the bio-toxin 

or add biochemical oxygen demand to already eutrophic downstream waters. Therefore 

we support the inclusion of lakes, ponds and wetlands with surface connection to waters 

in the definition of “Tributary”. (p. 5)

Agency Response: See the summary response for Section 8.2. In response to 

many public comments that found the proposed definition confusing, the definition 

of “tributary” has been clarified in the final rule, and no longer includes ponds, 

lakes, and wetlands as tributaries. Ponds, lakes and wetlands may still be waters of 

the United States if they meet the definition of “adjacent waters.” 

National Wildlife Federation (Doc. #15020)

8.317 ... [W]e strongly support the agencies’ preamble clarification that even when not 

jurisdictional waters, non-wetland swales, gullies, rills and specific types of ditches may 

still be a surface hydrologic connection for purposes of the proposed definition of 

adjacent under paragraph (a)(6) or for purpose of a significant nexus analysis under 

paragraph (a)(7). We also support the clarification that these geographic features may 

function as “point sources” under the CWA such that discharges of pollutants to waters 

through these features would subject to CWA permitting requirements such as CWA 

section 402. 79 Fed. Reg. at 22219. (p. 103)

Agency Response: Section IV(I) of the preamble to the final rule indicates that 

while the waters listed in the exclusions are never “waters of the United States,” 

they can serve as a hydrologic connection that the agencies would consider under a 

case-specific significant nexus under paragraphs (a)(7) and (a)(8). 

8.318 B. The Proposed Rule, much like the 2008 Guidance, properly treats many non-tidal 

ditches as tributaries where they clearly function as tributaries.

Ditches that clearly function as tributaries – contributing flow and pollutants downstream 

– are regulated as such under both the 2008 Guidance and the Proposed Rule. As the 

preamble explains, “[d]itches not excluded under paragraphs (b)(3) and (4) of the 

proposed regulation meet the definition of tributary where they have a bed and banks and 

ordinary high water mark and they contribute flow directly or indirectly through another 

water to (a)(1) through (a)(4) waters.” 79 Fed. Reg. at 22203.

We are generally supportive of the agencies’ proposed rule with respect to the 

jurisdictional treatment of non-tidal ditches and swales. Non-tidal ditches, including 

roadside and agricultural ditches, are complicated because they are sometimes carved out 

of upland, but are often constructed in natural streams and wetlands, are prevalent on the 

landscape, and where they connect directly or indirectly to the tributary system, they 

often contribute substantial amounts of pollution and flood water to downstream TNWs 

or IWs. Such ditch systems have wreaked havoc with water quality in some of the 

 

508 Microcystis Bloom Continues in the Transquaking River, Maryland Department of Natural Resources, Eyes on 

the Bay, May2, 2008.
Clean Water Rule Response to Comments – Topic 8: Tributaries

463

nation’s greatest aquatic ecosystems, including the Chesapeake Bay watershed and 

Mississippi River Basin and Gulf of Mexico.509

To maintain and restore the physical, chemical, and biological integrity of the nation’s 

waters, the pollution and flood waters conveyed to downstream tributaries from these 

tributary ditch systems must be subject to Clean Water Act regulation. The agencies have 

struck a reasonable balance, consistent with the CWA, the Supreme Court cases, and past 

practice, by treating non-tidal ditches as tributaries where they clearly function as 

tributaries: where they have a bed, bank, and OHWM, connect directly or indirectly to a 

TNW or IW, and otherwise function as a tributary and potential source of pollution. See 

79 Fed. Reg. at 22203.510

The preamble concludes, based on the science, that tributary ditches provide the same 

chemical, physical, and biological functions as other tributaries and have the requisite 

significant nexus to TNWs and IWs:

Tributary ditches and other man-made or man-altered waters, if they meet the 

definition of “tributary,” have a significant nexus to (a)(1) through (a)(3) waters 

due to their effects on the chemical, physical, or biological integrity of those 

downstream waters. As described above, tributaries of all flow regimes have a 

significant nexus to downstream (a)(1) through (a)(3) waters. Due to the often 

straightened and channelized nature of ditches, these tributaries quickly move 

water downstream to (a)(1) through (a)(3) waters. Ditches and canals, like other 

tributaries, export sediment, nutrients, and other materials downstream.”

79 Fed. Reg. at 22206.

EPA precedent for protecting man-made or altered waters that function as 

tributaries began quite early in the Act’s implementation. The agency’s General 

Counsel concluded in 1977 that the Arlington Canal, in Buckeye, Arizona, was a 

“water of the United States,” despite describing the Canal as:

[A]n earthen irrigation ditch which flows roughly parallel to the Gila River

[, which has flow that] consists primarily of groundwater pumped from wells, 

irrigation return flows and treated sewage effluent [and which] takes in water 

from the main Gila River channel only during periods of heavy flow when 

upstream users are not diverting all of the flow of the River.511

The opinion states that the “facts clearly support the Regional Administrator's finding 

that the Arlington Canal is a tributary of the Gila River, which is navigable water.”512

 

509 See, e.g., SAB Connectivity Peer Review Report at 23-24, 31-32. See also, Section IX.K. infra; Dr. Robert 

Magnien, Miles of Ditches have Altered Delmarva Peninsula Hydrology, Chesapeake Bay Journal April 1999 at 

http://www.bayjournal.com/article.cfm?article=2128 (last checked 11.12.14).

510 The agencies’ proposed criteria of an OHWM, a bed and bank, and additional criteria indicative of tributary 

function are criteria above and beyond existing regulatory requirements for what is considered a tributary.

511 U.S. EPA, Office of General Counsel, In re: Town of Buckeye, Arizona, 1977 WL 28254, at * 1 (Nov. 11, 1977).

512 Id. (citation omitted).
Clean Water Rule Response to Comments – Topic 8: Tributaries

464

And this conclusion was not an aberration; a separate opinion from the General Counsel 

two years earlier was consistent with this view.513

Since the passage of the Act, federal courts have consistently concluded that man-made 

channels can properly be considered “waters of the United States.” For instance, in a case 

involving the discharge of raw sewage during the 1970s into a Louisiana canal that was 

adjacent to (and from which water was periodically pumped into) wetlands that were 

considered to be “waters of the United States,” the court found that the canal could be 

protected either as a water linked to interstate commerce or as a tributary to the 

wetlands.514

In the last decade – both before and after SWANCC – numerous federal courts of appeal 

have found that ditches and canals properly could be protected “waters of the United 

States.” Specifically, the Fourth, Sixth, Seventh, Ninth, and Eleventh Circuits found that 

such features were properly protected by the Clean Water Act.515 Similarly, the Second 

Circuit rejected an attempt to limit jurisdiction over a natural tributary that had been 

“channeled in some places . . . into underground pipes to make room for development. . . 

.”516 Cases since Rapanos have similarly found that man-made or man-altered tributaries 

are jurisdictional.517

In keeping with this approach, the Bush Administration staunchly defended the protection 

of the entire tributary system, ditches included, before the Supreme Court. Solicitor 

General Clement explained “the definition of a tributary is basically any channelized 

body of water that takes water in a flow down to the traditional navigable water.”518

Specifically, he noted that “[t]he Corps has not drawn a distinction between man-made 

channels or ditches and natural channels or ditches. And, of course, it would be very 

absurd for the Corps to do that since the Erie Canal is a ditch.”

519

Even opponents of the continued broad scope of the Act recognize that ditches have long 

been covered by the Clean Water Act. One such opponent observed (in a 2006 email 

about the draft guidance sent to staff at the Council on Environmental Quality (“CEQ”))

 

513 U.S. EPA, Office of General Counsel, In re: Riverside Irrigation Dist., Ltd. & 17 Others, 1975 WL 23864, at *3-

4 (June 27, 1975) (discussing objection about irrigation return canals, EPA’s regulations defining “waters of the 

United States” and a judicial interpretation which noted that tributaries to navigable waters were protected, and 

concluding, “[i]t thus appears that the waters that are the subject of these permits may well be determined by the 

finder of fact, applying the statutory and regulatory test to the facts of these cases, to be navigable waters within the 

definition in the Act.”).

514 U.S. v. St. Bernard Parish, 589 F.Supp. 617, 620 (E.D. La. 1984).

515 S.Ct. 2964 (2006), on remand 464 F.3d 723 (7th Cir. 2006) (remanding to district court to apply Rapanos), cert. 

denied 128 S.Ct. 45 (2007); Headwaters, Inc. v. Talent Irrigation Dist., 243 F.3d 526, 533 (9th Cir. 2001) (holding 

that irrigation canals were “tributaries” protected as “waters of the United States”); U.S. v. Eidson, 108 F.3d 1336, 

1342 (11th Cir.) (“There is no reason to suspect that Congress intended to regulate only the natural tributaries of 

navigable waters. Pollutants are equally harmful to this country's water quality whether they travel along man-made 

or natural routes.”), cert. denied, 522 U.S. 899 (1997). 

516 U.S. v. TGR Corp., 171 F.3d 762, 765 (2d Cir. 1999).

517 See note 107, supra.

518 Transcript of Oral Argument, Rapanos v. United States, 126 S.Ct. 2208 (2006), at 39 (Feb. 21, 2006), available at 

http://www.supremecourt.gov/oral_arguments/argument_transcripts/04-1034.pdf.

519 Id.
Clean Water Rule Response to Comments – Topic 8: Tributaries

465

that ditches had “long been covered under [the] CWA,” and wondered whether excluding 

such “artificial” waters from coverage would create legal vulnerabilities.520 (p. 35-37)

Agency Response: The exclusions for ditches have been revised and clarified in 

the final rule (see Section 6.2 of the Ditches compendium of this RTC). Ditches that 

meet the definition of “tributary” in the final rule and are not excluded under 

paragraph (b), will be considered waters of the United States as tributaries. 

American Rivers (Doc. #15372)

8.319 2. Ensure that Wetlands that Connect Tributary Segments are Categorically Protected

The Agencies specifically request comment on whether wetlands that connect tributary 

segments and contribute flow at the upper reaches of a tributary system should be 

considered tributaries or adjacent waters. From an ecological perspective, these waters 

could be covered under either category. Most importantly, these waters should be 

categorically protected whether they are considered tributaries or adjacent waters. We 

recommend that these wetlands remain covered as a tributary, particularly in the context 

of our recommended revised definition of tributary. Much of the concern about whether 

these wetlands should be tributaries or adjacent waters is the result of the likely absence 

of an OHWM. By revising the definition of tributary to deemphasize this physical 

feature, we believe that wetlands that connect tributaries or provide headwaters can 

reasonably be considered under the tributary category. (p. 20)

Agency Response: See the summary response for Section 8.2. In response to 

many public comments that found the proposed definition confusing, the definition 

of “tributary” has been clarified in the final rule, and no longer includes ponds, 

lakes, and wetlands as tributaries. Ponds, lakes and wetlands may still be waters of 

the United States if they meet the definition of “adjacent waters.” Section (IV)(G) of 

the preamble and section VIII of the Technical Support Document discuss “adjacent 

waters.”

Natural Resources Defense Council et al. (Doc. #15437)

8.320 1. Request for comment on not treating waters without an ordinary high water mark as 

tributaries, even when they function as such.

The agencies request comment on whether features without an ordinary high water mark 

(OHWM) that contribute flow to downstream waters, such as wetlands and ponds, should 

be eligible to be considered tributaries, or if they should be treated exclusively as 

adjacent waters. The notice states:

 

520 Email from Jeff Eisenberg, National Cattleman’s Beef Ass’n, to Greg Schildwachter, CEQ, Sept. 13, 2006, at 1 

(produced in response to Freedom of Information Act by Council on Environmental Quality). The message went on 

to convey that, despite their legal concerns, “[w]e of course are happy to have ditches excluded.” See also Dialogue: 

Will the New Waters of the United States (WOTUS) Rule Float? 44 ELR 10862 (10-2014), Comments of Deidre 

Duncan (“It is true that the Corps has, in case-specific circumstances, regulated ditches in the sec. 404 program, but 

what is also clear is that ditches have not previously been regulated as waters of the United Sates under non-sec. 404 

CWA programs.”).
Clean Water Rule Response to Comments – Topic 8: Tributaries

466

An alternate approach would be to clarify that wetlands that connect tributary 

segments are adjacent wetlands, and as such are jurisdictional waters of the 

United States under (a)(6). In this approach, a tributary would be defined as 

having a bed and bank and OHWM, and the upper limit of the tributary would be 

defined by the point where these features cease to be identifiable. *** The 

agencies request comment on this alternate approach, as well as any other 

suggestions commenters may have on how to clarify the definition of tributaries 

and provide a clear explanation of their lateral and upstream extent”521

We strongly disagree with treating features that function as tributaries as anything but. 

Historically, the OHWM was used to establish the spatial limits of flowing waters in the 

Corps’ section 404 regulations,522 but was not a defining characteristic for “waters of the 

United States” more broadly. The proposal elevates this feature as an essential 

component of the definition of “tributary” for all Clean Water Act programs.

In our judgment, the primary import of OHWM (and bed and banks) in the proposal is to 

reflect the agencies’ intent that the rules apply only to real and permanent aquatic features 

(which includes waters that lack perennially flowing or standing water). That is, OHWM 

is an indicator of a geographic feature the shape of which is determined by the action 

over many years of hydrologic forces like flowing water. We support the goal of focusing 

these rules on recognized types of surface waters; doing so reflects the agencies’ 

longstanding practice of distinguishing between permanent aquatic features and places 

where water temporarily collects, like puddles or sheet flow.

Viewed in this context, we urge the agencies not to require wetlands and ponds that 

function as tributaries to have an OHWM in order to be considered tributaries under the 

rule.523 Rather, those features should continue be treated as tributaries, as in the proposed 

rule, and the definitions of various types of water bodies should include indicia of longterm hydrologic processes. For wetlands, for instance, the existing regulatory definition 

would suffice.

In addition to ignoring the functional role that tributary wetlands and ponds play, treating 

them only as adjacent waters could create a significant loophole in the rules. If tributary 

ponds were treated as adjacent waters, they would still be jurisdictional categorically, but 

wetlands adjacent to such ponds would not be categorically covered; instead, they could 

only be protected as “other waters.” (p. 60-61)

Agency Response: See the summary response for Section 8.2. In response to 

many public comments that found the proposed definition confusing, the definition 

of “tributary” has been clarified in the final rule, and no longer includes ponds, 

lakes, and wetlands as tributaries. Ponds, lakes and wetlands may still be waters of 

 

521 79 Fed. Reg. at 22,203.

522 33 C.F.R. § 328.4(c).

523 Indeed, we suggest that OHWM not be a threshold condition for flowing waters to be considered tributaries 

either. The SAB had similar advice, urging “EPA to reconsider the definition of tributaries because not all tributaries 

have ordinary high water marks. An ordinary high water mark may be absent in ephemeral streams within arid and 

semi-arid environments or low gradient landscapes where the flow of water is unlikely to cause an ordinary high 

water mark. The Board advises the agency to consider changing the wording in the definition to ‘bed, bank, and 

other evidence of flow.’” SAB Rule Review at 2.
Clean Water Rule Response to Comments – Topic 8: Tributaries

467

the United States if they meet the definition of “adjacent waters.” Section IV(G) of 

the preamble to the final rule and section VIII of the Technical Support Document 

discuss “adjacent waters.”

National Federation of Independent Business (Doc. #8319)

8.321 (4) The Proposed Regulation inappropriately asserts jurisdiction over almost any ditch

The Proposed Regulation provides that any “natural, man-altered, or man-made water 

body” with an ordinary high water mark will be considered a tributary, and therein 

requires the Agencies to assert jurisdiction over practically any land over which water 

occasionally flows by applying either the ‘continuous surface connection” or “nexus” 

tests. But, both Rapanos tests reject such an expansive interpretation of CWA 

jurisdiction. Rapanos, 547 U.S. at 731-32. Justice Kennedy’s “significant nexus test” was 

not intended to apply beyond wetlands to tributaries. And the plurality’s “continuous 

surface connection” test was intended to strictly limit CWA jurisdiction over tributaries, 

and would not justify assertions of jurisdiction over “ditches, channels and conduits.” Id. 

at 737-39. (p. 6)

Agency Response: The exclusions for ditches have been revised and clarified in 

the final rule (see Section 6.2 of the Ditches compendium of this RTC). Only ditches 

that meet the definition of “tributary” in the final rule and are not excluded under 

paragraph (b), will be considered waters of the United States as tributaries. Section 

I of the Technical Support Document discusses the legal basis of the final rule, 

including consistency with the statute and Supreme Court decisions. 

Earthjustice (Doc. #14564)

8.322 EPA also asked for comment on the potential exclusion of wetlands from the definition of 

tributary because, as EPA argues, they lack a bed, bank, or ordinary high water mark. 79 

Fed. Reg. at 22206. ICL strongly opposes this suggestion as it is not supported by the 

science or simple facts on the landscape. In fact, wetlands are often tributaries to water of 

the U.S.—for example, the large wetland complexes like those that used to exist across 

the U.S., and still do to a lessened degree in the Red River area between Minnesota and 

North Dakota (the ancient Lake Agassiz plain), are tributaries. The large flat wetlands 

complex, on its western edge, would begin to form small streams draining to the Red 

River in the west, once the topography started to become less flat. The wetlands complex 

was clearly a tributary to the Red River and contributed flow to the river. See also

discussion of Red River in the Connectivity Report. Similarly, peatlands in the northern 

Great Lakes states and in some areas of the east and northeast plainly demonstrate flow in 

their topography (e.g. teardrop shapes of vegetated “islands” within the peatlands), see 

e.g., Patterned Peatlands of Minnesota, H.E. Wright Jr. and Norman Aaseng, eds. (1992), 

and are the headwaters of numerous streams and rivers including the St. Louis River in 

Minnesota that originates in the Hundred Mile Swamp then flows through Partridge River 

and enters Lake Superior at Duluth’s harbor. See EPA Reg. 5, Comment on NorthMet 

Project - Draft Environmental Impact Statement CEQ# 20090387 (Feb. 18, 2010). There 

is no scientific support for the removal of wetlands from the definition of tributary (and 

indeed there is scientific evidence directly contrary to doing so.) See also, Connectivity 
Clean Water Rule Response to Comments – Topic 8: Tributaries

468

Report at 1-8 (nutrient removal and cycling) and Member Comments Rosi-Marshall at 

81, and Sullivan at 85. (p. 6-7)

Agency Response: See the summary response for Section 8.2. In response to 

many public comments that found the proposed definition confusing, the definition 

of “tributary” has been clarified in the final rule, and no longer includes ponds, 

lakes, and wetlands as tributaries. Ponds, lakes and wetlands may still be waters of 

the United States if they meet the definition of “adjacent waters.” Section IV(G) of 

the preamble to the final rule and section VIII of the Technical Support Document 

discuss “adjacent waters.”

Center for Rural Affairs (Doc. #15029)

8.323 The current definition of tributary in the proposed rule provides descriptions of physical 

demarcations—a bed and banks along with an ordinary high water mark—that would 

help landowners easily identify a tributary on their property. The inclusion of wetlands as 

potential tributaries, however, introduces more confusion than clarity. As acknowledged 

in the rule, wetlands can serve as tributaries by contributing flow to a jurisdictional water 

either directly or through another water. Although these wetlands may warrant 

jurisdiction, not all wetlands contribute flow to (a)(1) through (4) waters and, as such, 

could not be classified as tributaries. The inclusion of wetlands as possible tributaries 

effectively rescinds any clarity provided by the bed, banks, and ordinary high water mark 

criteria previously established.

While this vagueness may work for lakes or ponds lacking an ordinary high water mark 

where contribution of flow to a jurisdictional water would be more obvious, such a 

connection would be less apparent when it comes to wetlands. We do not dispute that 

wetlands can contribute flow—either directly or through another water—and act as a 

tributary, but for the sake of reducing ambiguity, it would be best to reconsider this 

addition of wetlands to the tributary definition. Wetlands directly contributing flow to a 

traditionally navigable water would be considered adjacent waters and would therefore 

remain jurisdictional. Nonadjacent wetlands with a more obscure connection to 

traditionally navigable waters could still be jurisdictional as “other waters” pending a 

significant nexus determination.

Recommendation: Remove wetlands from the definition of tributary, covering them 

instead as either adjacent waters or other waters subject to a significant nexus test. (p. 3)

Agency Response: See the summary response for Section 8.2. In response to 

many public comments that found the proposed definition confusing, the definition 

of “tributary” has been clarified in the final rule, and no longer includes ponds, 

lakes, and wetlands as tributaries.

Alabama Rivers Alliance (Doc. #14280)

8.324 ..we support EPA’s inclusion in the definition of “waters of the US” all tributaries and 

adjacent wetlands as well as the proposed cumulative analysis of similarly situated 

waters. Watershed networks are inherently connected, and failure to protect small 
Clean Water Rule Response to Comments – Topic 8: Tributaries

469

upstream tributaries could result in “alterations [to] downstream hydrology, water quality, 

biota and geomorphic processes.”524

Environment North Carolina Research and Policy Center’s timely report “Waterways 

Restored: The Clean Water Act’s Impact on 15 American Rivers, Lakes and Bays” 

succinctly explains that, despite great progress in restoring our nations great waters, ”[n]o 

places are more vulnerable or more important to the overall protection of waterways than 

headwaters and tributaries.”525 We strongly support SELC’s recommended that ”[t]he 

term “tributaries” should be redefined so that it is clear that for the purposes of this rule 

wetlands, lakes, and ponds that contribute flow to a tributary system are clearly included 

in the term and thus do not require case-by-case jurisdictional analysis."526 For the 

purposes of the rule, the term “tributary” should mean:

“1) a water (such as a stream, creek, or river) that has a bed and bank and ordinary 

high water mark and that contributes flow to other jurisdictional waters either 

directly or through another water or a discrete conveyance; or

2) a nonlinear water (such as a wetland, lake, or pond) even if it does not possess 

a bed or bank or ordinary high water mark as long as it contributes flow to other 

jurisdictional waters either directly or through another water or a discrete 

conveyance.”527 (p. 2-3)

Agency Response: See the summary response for Section 8.2. In response to 

many public comments that found the proposed definition confusing, the definition 

of “tributary” has been clarified in the final rule, and no longer includes ponds, 

lakes, and wetlands as tributaries. Ponds, lakes and wetlands may still be waters of 

the United States if they meet the definition of “adjacent waters.” Section IV(G) of 

the preamble to the final rule and section VIII of the Technical Support Document 

discuss “adjacent waters.”

Atlanta Audubon Society (Doc. #14281)

8.325 ...Although the proposed definition is correct in principle, it contains an internal 

contradiction. It is confusing in how it first defines tributaries as those waters that contain 

a bed, banks, and an ordinary high water mark, but then includes waters in the definition 

that often do not exhibit such features, such as wetlands, lakes, and ponds. We believe 

that to avoid this internal conflict, the tributary definition should resemble the substitute 

definition provided by SELC... To the extent that there is concern that such a definition 

would cover insignificant features such as puddles, gutters, and upland roadside ditches, 

 

524 Southern Environmental Law Center, Comments On “Definition of ‘Waters of the United States’ Under the 

Clean Water Act, Proposed Rule,” 79 Fed. Reg. 22188-22271, November 13, 2014, p. 48 (citing Freeman, M.C., 

C.M. Pringle and R.J. Jackson. 2007. Hydrologic Connectivity and the Contribution of Stream Headwaters to 

Ecological Integrity at Regional Scales. Journal of the American Water Resources Association. 43(1): 6-14.)

525 Environment North Carolina Research and Policy Center, “Waterways Restored: The Clean Water Act’s Impact 

on 15 American Rivers, Lakes, and Bays”, October 2014, p. 33. Available at : 

http://environmentnorthcarolinacenter.org/reports/ncc/waterways-restored (Last accessed November 14 2014)

526 SELC Comments at 4.

527 Id. at 13.
Clean Water Rule Response to Comments – Topic 8: Tributaries

470

the agencies could define waters to exclude such features. Or preamble language could be 

drafted to address this issue. (p. 2-3)

Agency Response: See the summary response for Section 8.2. In response to 

many public comments that found the proposed definition confusing, the definition 

of “tributary” has been clarified in the final rule, and no longer includes ponds, 

lakes, and wetlands as tributaries. Ponds, lakes and wetlands may still be waters of 

the United States if they meet the definition of “adjacent waters.” Section IV(G) of 

the preamble to the final rule and section VIII of the Technical Support Document 

discuss “adjacent waters.” Paragraph (b) of the final rule excludes many features 

from consideration as waters of the United States, including puddles and most 

ditches. Stormwater control features constructed in dry land are also excluded as 

waters of the United States in paragraph (b), and as the preamble to the final rule 

notes, curbs and gutters have never been considered waters of the United States. 

Stormwater control features constructed in dry land are excluded as waters of the 

United States in paragraph (b).

Clean Water Action et al. (Doc. #14884)

8.326 In addition, we support the Agencies’ definition of tributary and strongly agree that 

ditches should be defined as “waters of the U.S.” where they function as tributaries. 

There is sufficient scientific evidence that some ditches function as tributaries moving 

water and pollutants downstream. In those cases protection is important. (p. 2)

Agency Response: The exclusions for ditches have been revised and clarified in 

the final rule (see Section 6.2 of the Ditches compendium of this RTC). The agencies 

agree that some ditches may function as tributaries, and only ditches that meet the 

definition of “tributary” in the final rule and are not excluded under paragraph (b), 

will be considered waters of the United States as tributaries. 

Conservancy of Southwest Florida (Doc. #14980)

8.327 Support for the Definition of Tributaries

The Clean Water Rule definition of jurisdictional tributaries is of particular relevance to 

Southwest Florida. Due to the vast hydrologic alterations of the region - including miles 

of manmade canal systems which drain historic wetlands and sheet flow areas to in order 

to facilitate development and agriculture - the proposed definition of tributary will clarify 

that these man-altered natural streams, wholly manmade canals and natural streams with 

control structures, such as tidal streams with berms or dams, are considered jurisdictional 

if they meet the definition of tributary. While tidally influenced areas are considered 

jurisdictional under (a)(1) of both the proposed and existing rule, many of the tidally 

influenced waterbodies also have a dam, weir or other associated structure. The proposed 

definition will clarify that the upstream portions beyond the control structure are also 

considered categorically jurisdictional....

...Moreover, the Conservancy supports the definition of tributary for categorically 

defining as WUS all tributaries and their adjacent waters, including ditches that function 

as tributaries with the exception of those which meet the exclusion criteria by paragraphs 

(b)(3) and (b)(4) of the proposed rule. (p. 3)
Clean Water Rule Response to Comments – Topic 8: Tributaries

471

Agency Response: The exclusions for ditches have been revised and clarified in 

the final rule (see Section 6.2 of the Ditches compendium of this RTC). The agencies 

agree that some ditches may function as tributaries, and only ditches that meet the 

definition of “tributary” in the final rule and are not excluded under paragraph (b), 

will be considered waters of the United States as tributaries. 

Clean Water Action Maryland et al. (Doc. #15072)

8.328 Our organizations also support the Agencies’ determination that all adjacent 

wetlands are “Waters of the U.S.” Wetlands perform critical functions that support 

aquatic life, clean drinking water and safeguard communities from floods. Wetlands 

protect the water quality of entire watersheds by filtering pollutants. They also store 

floodwaters, reducing flood flows that can threaten property and infrastructure. A single 

acre of wetland can store 1 to 1.5 million gallons of flood water. Wetlands in the 

continental United States save an estimated $30 plus billion in annual flood damage 

repair costs. Wetlands also provide essential fish and wildlife habitat that support robust 

fishing and outdoor recreation and tourism economy in Maryland. When wetlands are 

polluted, dredged or filled, these benefits are lost. (p. 2)

Agency Response: The definition of “adjacent waters” has been revised and 

clarified for the final rule. Section IV(G) of the preamble to the final rule and 

section VIII of the Technical Support Document discuss “adjacent waters.”

8.329 In addition, we support the Agencies’ definition of tributary and strongly agree that 

ditches should be defined as “waters of the U.S.” where they function as tributaries.

There is sufficient scientific evidence that some ditches function as tributaries moving 

water and pollutants downstream. In those cases protection is important. (p. 3)

Agency Response: The exclusions for ditches have been revised and clarified in 

the final rule (see Section 6.2 of the Ditches compendium of this RTC). The agencies 

agree that some ditches may function as tributaries, and only ditches that meet the 

definition of “tributary” in the final rule and are not excluded under paragraph (b), 

will be considered waters of the United States as tributaries.

Tulane Environmental Law Clinic et al (Doc. #15123)

8.330 ...We further support the proposed Rule’s explanation that wetlands and other waters 

located alongside, next to, or otherwise adjacent to any tributary are themselves waters of 

the United States for the same reason – these waters are physically, chemically and 

biologically connected to traditionally navigable waters. (p. 1)

Agency Response: The definition of “adjacent waters” has been revised and 

clarified for the final rule. Section IV(G) of the preamble to the final rule and 

section VIII of the Technical Support Document discuss “adjacent waters.”

Stormwater Management Commission, Lake County, Illinois (Doc. #15381)

8.331 32 8(c)(5) = Tributary : We are in general support of this term as defined. However, we 

are concerned that the inclusion of 'man-made' features could create confusion with 

respect to the ditch exclusions in §328(b)(3-4). We suggest modifying the final sentence 

to omit 'man-made' from the definition. (p. 3)
Clean Water Rule Response to Comments – Topic 8: Tributaries

472

Agency Response: See summary resposne for section 8.1. Paragraph (b) of the 

final rule clearly states that the excluded features identified therein “are not waters 

of the United States even where they otherwise meet the terms of paragraphs (a)(1) 

through (a)(8)” of the rule. Thus, neither an excluded ditch nor any other excluded 

feature may be considered waters of the United States under any other provision of 

the rule.

Wisconsin Wetlands Association (Doc. #15629)

8.332 We support the language clarifying that wetlands contributing flow to other waters will 

be considered tributaries and agree that defining these wetlands as tributaries is more 

appropriate than defining them as adjacent waters. The intent to classify headwater 

wetlands and other source waters as tributaries could be further clarified by mentioning 

springs and seeps as examples of other waters that will meet the definition where physical 

evidence is present. (p. 2)

Agency Response: See the summary response for Section 8.2. In response to 

many public comments that found the proposed definition confusing, the definition 

of “tributary” has been clarified in the final rule, and no longer includes ponds, 

lakes, and wetlands as tributaries. Ponds, lakes and wetlands may still be waters of 

the United States if they meet the definition of “adjacent waters.” Section IV(G) of 

the preamble to the final rule and section VIII of the Technical Support Document 

discuss “adjacent waters.” 

The River Alliance of Wisconsin (Doc. #16344)

8.333 A broader definition of tributary in (u)(5) should incorporate a more scientific 

understanding of what constitutes a tributary. This will fulfill the purpose of the CWA to 

prevent pollutants that are dumped into any part of the tributary system and eventually 

are washed downstream to traditional navigable waters, interstate waters, or the territorial 

seas where those pollutants endanger public health and the environment. Broadening the 

definition to not restrict a tributary as having bed, banks and an ordinary high water mark 

would also allow wetlands to be included within the definition of tributaries. In 

Wisconsin, there are river systems where there is “grey area” between tributaries and 

wetlands. For example, the headwaters of the Bad River are a system of wetlands rather 

than tributaries as narrowly defined in the proposed rule and activities that degraded these 

headwaters would result in degradation of the water quality of the Bad River itself. It 

makes sense to define tributaries by their function and connectivity, rather than a set of 

narrow physical characteristics. (p. 2)

Agency Response: See the summary response for Section 8.2. In response to 

many public comments that found the proposed definition confusing, the definition 

of “tributary” has been clarified in the final rule, and no longer includes ponds, 

lakes, and wetlands as tributaries. Ponds, lakes and wetlands may still be waters of 

the United States if they meet the definition of “adjacent waters.” Section IV(G) of 

the preamble to the final rule and section VIII of the Technical Support Document 

discuss “adjacent waters.” 
Clean Water Rule Response to Comments – Topic 8: Tributaries

473

Defenders of Wildlife and Patagonia Area Resource Alliance (Doc. #16394)

8.334 EPA also asked for comment on the potential exclusion of wetlands from the definition of 

tributary because they lack a bed, bank, or ordinary high water mark. 79 Fed. Reg. at 

22206. As described more fully by Earthjustice, we strongly oppose this suggestion 

because wetlands are often tributaries to waters of the U.S. and should be treated as such. 

(p. 7)

Agency Response: See the summary response for Section 8.2. In response to 

many public comments that found the proposed definition confusing, the definition 

of “tributary” has been clarified in the final rule, and no longer includes ponds, 

lakes, and wetlands as tributaries. Ponds, lakes and wetlands may still be waters of 

the United States if they meet the definition of “adjacent waters.” Section IV(G) of 

the preamble to the final rule and section VIII of the Technical Support Document 

discuss “adjacent waters.” 

Michigan United Conservation Clubs (Doc. #16395)

8.335 It is also important to note that Michigan’s law exempts many lakes, ponds, and “noncontiguous” wetlands less than 5 acres in size. Michigan law also includes broad 

exemptions for agriculture, silviculture, ranching, iron and copper processing, drainage 

ditches, and oil and gas pipelines. Significantly, Michigan’s past economic woes has led 

to very significant cutbacks in Michigan’s water permitting programs in 2008 and 2009, 

though they have been increased in recent years. While we strongly support Michigan’s 

program, it takes constant vigilance and commitment within the administration and 

Michigan Legislature to keep it adequately funded.

Absent Michigan’s assumption of the Section 402 and 404 Programs, much of our waters 

would be unregulated in Michigan. EPA estimates that 48 percent of Michigan’s streams 

have no other streams flowing into them, and that 36 percent do not flow year-round. 

Under varying interpretations of the most recent Supreme Court decision, these smaller 

water bodies are among those for which the extent of Clean Water Act protections has 

been questioned. EPA also says that 1,400,633 people in Michigan receive some of their 

drinking water from areas containing these smaller streams and that at least 163 facilities 

located on such streams currently have permits under the federal law regulating their 

pollution discharges. Also, Michigan’s Department of Environmental Quality estimated 

that 930,856 acres of wetlands in the state, along with 26,384 lakes and ponds, could be 

considered so-called “isolated” waters – water bodies that are particularly vulnerable to 

losing Clean Water Act safeguards if Michigan’s program is not maintained or funded. In 

view of all of these facts, perhaps it’s not surprising that Michigan joined over 30 states 

in asking the Supreme Court to uphold broad legal protections for small tributaries and 

their adjacent wetlands.
Clean Water Rule Response to Comments – Topic 8: Tributaries

474

Waters of the United States: Michigan. In Michigan 33% of stream miles within native trout historical range are 

classified as intermittent or ephemeral. 59% of stream miles are in headwater streams. In the AuSable River basin, 

35% of streams are intermittent while 53% are headwaters.

(p. 2-4)

Agency Response: The agencies consider the commenter’s remarks statements of 

fact and have no response regarding the State of Michigan’s regulatory programs.

Waterkeeper Alliance et al. (Doc. #16413)

8.336 With regard to tributaries, the Proposed Definition states "[a] tributary, including 

wetlands, can be a natural, man-altered, or man-made water and includes waters such as 

rivers, streams, lakes, ponds, impoundments, canals, and ditches not excluded in 

paragraph (2)(iii) or (iv) of this definition." There are compelling legal and scientific 

reasons for ensuring that man-altered and man-made waters are covered as tributaries, 

and those reasons apply equally to ditches. As the 11th Circuit stated in the case of U.S. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

475

v. Eidson, "[t]here is no reason to suspect that Congress intended to regulate only the 

natural tributaries of navigable waters. Pollutants are equally harmful to this country's 

water quality whether they travel along man-made or natural routes."528

We believe that ditches should be categorically included when they otherwise meet the 

definition of a "water of the United States," including specifically a tributary. We also 

believe that ditches should be protected when they meet either the "relatively permanent" 

or "significant nexus" test without regard to the agencies' unspecified policy 

considerations. The agencies do not possess the authority to exclude waters that Congress 

intended to cover from the definition of "waters of the United States" for policy or any 

other agency administrative purpose."529 (p. 35)

Agency Response: The exclusions for ditches have been revised and clarified in 

the final rule (see Section 6.2 of the Ditches compendium of this RTC). The agencies 

agree that some ditches may function as tributaries, and only ditches that meet the 

definition of “tributary” in the final rule and are not excluded under paragraph (b), 

will be considered waters of the United States as tributaries.

Red River Valley Association (Doc. #16432)

8.337 Although the Proposed Rule would exclude two types of ditches from CWA jurisdiction, 

ditches that do not meet the criteria for exclusion could be considered waters of the 

United States. The proposed definition of "tributary" could be interpreted to include manmade waters with artificial features, such as drainage ditches or artificial ponds. Also, 

ditches with perennial flow are not covered by the exemption, but it is not clear what the 

agencies believe is meant by "perennial flow." (p. 3)

Agency Response: The exclusions for ditches have been revised and clarified in 

the final rule (see Section 6.2 of the Ditches compendium of this RTC). The agencies 

agree that some ditches may function as tributaries, and only ditches that meet the 

definition of “tributary” in the final rule and are not excluded under paragraph (b), 

will be considered waters of the United States as tributaries. The final rule is 

consistent with the agencies’ longstanding interpretation of the CWA that a

tributary can be a natural, man-altered, or man-made water. Section IV(F) of the 

preamble to the final rule and section VII of the Technical Support Document 

discuss tributaries, including man-made or man-altered tributaries. See also the 

summary response for “Relevance of Flow Regime” in section 8.1.1 above, 

particularly the subsection on “Regulation of Man-Altered Streams” and the 

summary response for section 8.2 above, “Ditches as Tributary.” Paragraph (b) of 

the final rule excludes many features from consideration as waters of the United 

States, including artificial lakes and ponds created in dry land and used primarily 

for such uses as stock watering, irrigation, etc. As noted in section IV(F) of the 

preamble, longstanding agencies’ practice considers perennial streams as those with 

flowing water year-round during a typical year, with groundwater or contributions 

 

528 US. v. Eidson, 108 F.3d 1336, 1342, (11th Cir.1997) cert. denied, 522 U.S. 899 (1997).

529 1972 Legislative History, supra note 14, p. 327; NRDC v. Callaway, 392 F.Supp. 685, 686 (D.D.C.

1975); Cf NRDC. v. Castle, 568 F.2d at 1377.
Clean Water Rule Response to Comments – Topic 8: Tributaries

476

of flow from higher in the stream or river network as primary sources of water for 

stream flow.

Ruby Valley Conservation District, Montana (Doc. #16477)

8.338 our Board requests that ditches be removed from the definition defining tributaries and 

remove the provision that makes isolated wetlands, ponds, and other open waters per se 

jurisdictional if they are located within a riparian area or floodplain. (p. 1)

Agency Response: The exclusions for ditches have been revised and clarified in 

the final rule (see Section 6.2 of the Ditches compendium of this RTC). Some 

ditches may function as tributaries, and only ditches that meet the definition of 

“tributary” in the final rule and are not excluded under paragraph (b), will be 

considered waters of the United States as tributaries. The final rule is consistent 

with the agencies’ longstanding interpretation of the CWA that a tributary can be a 

natural, man-altered, or man-made water. Section IV(F) of the preamble to the 

final rule and section VII of the Technical Support Document discuss tributaries, 

including man-made or man-altered tributaries. See also the summary response for 

“Relevance of Flow Regime” in section 8.1.1 above, particularly the subsection on 

“Regulation of Man-Altered Streams” and the summary response for section 8.2 

above, “Ditches as Tributary.” In response to many public comments that found 

the proposed definition confusing, the definition of “tributary” has been clarified in 

the final rule, and no longer includes ponds, lakes, and wetlands as tributaries. 

Ponds, lakes and wetlands may still be waters of the United States if they meet the 

definition of “adjacent waters.” Section IV(G) of the preamble to the final rule and 

section VIII of the Technical Support Document discuss “adjacent waters.” 

Society for Freshwater Science (Doc. #11783)

8.339 Along with our support of most components, we would also like to express our concern 

over the following proposed elements... Second, we are concerned about tributaries that 

have been altered or created. Suburban and urban channels that have been transformed 

into part of the current stormwater infrastructure ought to be considered tributaries. The 

fact that they have been altered does not change their importance to water quality. 

Similarly, agriculturally channelized headwaters and/or created channels (e.g., ditches) 

that become part of the tributary system, by very presence of the connection, are 

connected to and therefore influential upon downstream water quality and cannot be 

ignored or exempted. These waters deserve protection as jurisdictional waters and it 

should be added, distinguished, or confirmed that such tributary waters are still 

jurisdictional; this critical issue is unclear to us in the current proposed rule. (p. 2-3)

Agency Response: Paragraph (b) of the final rule specifically excludes stormwater 

control features constructed in dry land. Section IV(I) of the preamble to the final 

rule reiterates the agencies’ longstanding practice to view stormwater water control 

measures that are not built in “waters of the United States” as non-jurisdictional. 

Conversely, the agencies view some waters, such as channelized or piped streams, as 

jurisdictional currently even where used as part of a stormwater management 

system. Nothing in the proposed rule was intended to change that practice, and the 

final rule likewise leaves this policy in place.
Clean Water Rule Response to Comments – Topic 8: Tributaries

477

Florida Stormwater Association (Doc. #14613)

8.340 We recommend that the definition of “tributary” be revised to delete all language after 

the end of the first sentence of the proposed definition (i.e. delete all “additional” 

references) that add wetlands, lakes, ponds, impoundments, canals and ditches, whether 

they are natural, man-altered, or man-made.

Concerning ditches and whether they already should or should not be considered to be 

tributaries and therefore jurisdictional waters, EPA has stated during numerous 

conference calls, webinars and other meetings (both public and those that are less formal) 

that ditches and other conveyances with standing water in them already are or should be 

determined to be waters of the United States. This obviously begs the question: Why is it 

necessary to categorically include the term “ditches” within the definition of tributaries if 

they are already subject to existing regulations? (p. 7)

Agency Response: The exclusions for ditches have been revised and clarified in 

the final rule (see Section 6.2 of the Ditches compendium of this RTC). The agencies 

agree that some ditches may function as tributaries, and only ditches that meet the 

definition of “tributary” in the final rule and are not excluded under paragraph (b), 

will be considered waters of the United States as tributaries. The final rule is 

consistent with the agencies’ longstanding interpretation of the CWA that a

tributary can be a natural, man-altered, or man-made water. Section IV(F) of the 

preamble to the final rule and section VII of the Technical Support Document 

discuss tributaries, including man-made or man-altered tributaries. See also the 

summary response for “Relevance of Flow Regime” in section 8.1.1 above, 

particularly the subsection on “Regulation of Man-Altered Streams” and the 

summary response for section 8.2 above, “Ditches as Tributary.” See also the 

summary response for Section 8.2. In response to many public comments that 

found the proposed definition confusing, the definition of “tributary” has been 

clarified in the final rule, and no longer includes ponds, lakes, and wetlands as 

tributaries. Ponds, lakes and wetlands may still be waters of the United States if 

they meet the definition of “adjacent waters.” Section IV(G) of the preamble to the 

final rule and section VIII of the Technical Support Document discuss “adjacent 

waters.” 

Robert J. Pierce, PhD, Wetland Science Applications, Inc. (Doc. #4958)

8.341 The concept that lakes and ponds that lack either an OHWM or bed and bank (excluding 

those ringed by wetlands on the edge) are still tributaries is inappropriate. In the absence 

of wetlands, the OHWM is the end of COE jurisdiction [33 CFR 328.4(C)(l)]. This 

definition of tributary would open up all types of landscapes to dispute. With its adoption, 

puddles can become ponds or lakes. Furthermore, canals and ditches should not be 

regulated as tributaries unless in the case of canals there is actual navigation on the water 

and in the case of ditches the ditch is actually a channelized stream that otherwise is 

jurisdictional.

Ditches are Point Sources pursuant to Sec 502(14) of the CWA and whether they flow for 

any specified period of time or not should not be called tributaries. This proposed 

definition again treads on States' rights as expressed in Section 101 (b) of the CWA and 
Clean Water Rule Response to Comments – Topic 8: Tributaries

478

is unconstitutional. The fact is that the CWA allows for enforcement of its provisions 

where point sources connect to Section 10 waters and the enforcement action can pursue 

the violator to the source. As structured, the definition is simply an attempt to do federal 

land management - a right and responsibility of the States - not the federal government. 

(p. 9)

Agency Response: See the summary responses for Sections 8.1 and 8.2. Section I 

of the Technical Support Document provides the legal framework under which a 

ditch could be considered both a point source and a water of the United States. 

Section I of the Technical Support Document also discusses the broader legal basis 

of the final rule, including consistency with the statute and Supreme Court 

decisions. 

O'Neil LLP (Doc. #16559)

8.342 ...the Agencies should clarify in any final Rule, that riparian areas tapped into shallow 

groundwater within floodplains that otherwise lack indicators for an OHWM and that 

also fail to exhibit all three wetland criteria are not subject to CWA jurisdiction. Many 

non-wetland riparian trees and shrubs are phreatophytes or facultative phreatophytes, 

capable of obtaining water from a groundwater table that is well below the surface and 

therefore not a component of wetland hydrology. Such areas are currently not subject to 

CWA jurisdiction as wetlands (as explained, for example, on pages 90-91 of the Arid 

West Supplement Version 2.0). (p. 4)

Agency Response: See the summary responses for Sections 8.1 and 8.2. The term 

“riparian area” has been removed from the definition of “neighboring,” which is a 

component of “adjacent” in the final rule.

8.3. RELEVANCE OF BREAKS IN OHWM

Agency Summary Response

The final rule asserts jurisdiction over tributaries when there are breaks (natural or manmade) in 

the OHWM along the tributary. The definition of tributary in the rule states, "A water that 

otherwise qualifies as a tributary under this definition does not lose its status as a tributary if, for 

any length, there are one or more man-made breaks (such as bridges, culverts, pipes, or dams), or 

one or more natural breaks (such as wetlands along the run of a stream, debris piles, boulder 

fields, or a stream that flows underground) so long as a bed and banks and an ordinary high 

water mark can be identified upstream of the break."

Issue: General Comments Opposing and Supporting Approach to Break in OHWM

A number of commenter’s stated that the rule language regarding break in OHWM is 

inconsistent with the science, existing policy, and the preamble language in the proposed rule. 

One commenter stated that there is no scientific support to the Agencies assertion of categorical 

jurisdiction over manmade conveyances regardless of a break in OHWM. Another commenter 

stated the Agencies are excluding information from the Science Report on human modified 

streams that tends to undercut the rule’s treatment of breaks in OHWM and the categorical 
Clean Water Rule Response to Comments – Topic 8: Tributaries

479

inclusion of such features as tributaries. Another commenter stated the definition is subjective 

since the Agencies have determined that in certain regions of the country the presence of a bed 

and bank is not necessary. A number of commenters stated that extending jurisdiction beyond 

the break in OHWM is not consistent with traditional methods of determining jurisdiction, has 

no meaningful connection to TNWs, and will be an expansion of jurisdiction. Many commenters 

stated that the uncertainty created by a break in OHWM and the Agencies decision to still assert 

categorical jurisdiction over these features as tributaries does not provide the clarity, certainty or 

bright lines that the rule is supposed to provide.

A number of commenters were generally supportive of the rule’s approach to breaks in OHWM, 

and sought clarification from the Agencies that the reach of the break in OHWM itself is 

jurisdictional. One commenter suggested that even if the feature flows underground for some 

distance, such water should be jurisdictional for the underground portion as well as the aboveground portion. 

The Agencies respectfully disagree that the rule’s approach to a break in OHWM is inconsistent 

with the science, existing policy, traditional methods of determining jurisdiction, or is an 

expansion of jurisdiction. Streams with a break in OHWM can be WOUS under current practice 

(2008 Rapanos Guidance and the currently used Approved Jurisdictional Determination Form 

footnote 6 page 3 which was developed in concert with 2008 Rapanos Guidance). The Approved 

Jurisdictional Determination Form states that “a natural or man-made discontinuity in the 

OHWM does not necessarily sever jurisdiction (e.g., where the stream temporarily flows 

underground, or where the OHWM has been removed by development or agricultural practices). 

Where there is a break in the OHWM that is unrelated to the waterbody’s flow regime (e.g., flow 

over a rock outcrop or through a culvert), the agencies will look for indicators of flow above and 

below the break. The agencies position is supported by the science and the Science Report which 

discusses how breaks in stream channel characteristics change the nature of the connection to 

downstream waters but do not remove it, e.g. piping or channelization may remove all non-bed 

and bank indicators of OHWM and reduce lateral connectivity but actually increase downstream 

connectivity by concentrating and speeding up the delivery of water downstream. See also the 

summary responses in Section 9 “Scientific Evidence Supporting the Rule” of the Response to 

Comments. The final rule also does not change the longstanding practice that if there is a break 

in OHWM where the water flows underground without a surface expression of flow path, the 

portion of the flow path that is underground is not jurisdictional. 

Streams with a break in OHWM can be WOUS under current practice. The final rule does not 

change this practice, and includes a definition of tributary which was modified in response to 

comments to provide increased clarity.

Issue: Difficulties in determining OHWM, length of break, and contribution of flow

A number of commenters stated that in determining the OHWM, it is very hard to distinguish

between ephemeral streams and erosion-based channels, and that two of the three OHWM 

indicators should be required. A number of commenters requested a reasonable limit on the 

length of the break in OHWM in order for the feature to remain a tributary. Some commenters 

also asked how the time it takes for water to make the connection between the waters above and 

below a break in OHWM affects the jurisdictional determination. A number commenters also 
Clean Water Rule Response to Comments – Topic 8: Tributaries

480

sought clarification of how far upstream a farmer or rancher must look to find the bed and banks 

and OHWM.

The Agencies agree that determining the OHWM can be challenging. The final rule adds the 

Corps’ existing regulatory OHWM definition to EPA’s regulations, and the preamble notes that 

several Corps technical manuals are available to help identify OHWM. For areas such as the 

arid west and western mountains OHWM delineation manuals have been developed. The final 

rule does not change the definition or alter the methods for identification of OHWM. As such, 

the identification of OHWM will continue to be guided by the statements from RGL 05-05, 

including: 

There are no “required” physical characteristics that must be present to make an OHWM 

determination. However, if physical evidence alone will be used for the determination, 

districts should generally try to identify two or more characteristics, unless there is 

particularly strong evidence of one.

With regard to the challenges faced by farmers and ranchers in finding the bed and banks and 

OHWM, the Agencies note that certain ditches are excluded from the final rule under section (b), 

and the current ranching, silviculture, and forestry exemptions of CWA section 404(f) are not 

changed. In addition, some ditch maintenance work that is not exempted may be covered by 

non-reporting NWP 3.

The upper limit of the tributary is the point where a bed and banks and another indicator of 

ordinary high water mark cease to be identifiable. The ordinary high water mark establishes the 

lateral limits of a water, and its absence generally determines when a tributary’s channel or bed 

and banks has ended, representing the upper limit of the tributary. However, a natural or 

constructed break in bed and banks or other indicator of ordinary high water mark does not 

constitute the upper limit of a tributary where bed and banks or other indicator ordinary high 

water mark can be found farther upstream. By looking to the presence of a bed and banks and an 

ordinary high water mark upstream, the rule ensures that a mere break in the ordinary high water 

mark does not render tributaries with a significant nexus to downstream waters not jurisdictional. 

Thus, the Agencies believe that under current practice, which is not changed by this final rule, a 

reasonable limit on the length of the break in OHWM exists.

With regard to clarification of how far upstream a farmers and ranchers must look to find the bed 

and banks and OHWM, the Agencies have regulated all tributaries, including tributaries with 

breaks in bed and banks and OHWM, throughout regulatory history under the CWA. The 

Agencies believe that requiring the physical indicators of bed and banks and OHWM will help 

clarify that only water bodies with sufficient flow will meet the definition tributary. While 

science does not set a threshold distance that a break in the bed and banks or OHWM must be in 

order to maintain connectivity with the upstream portion of the tributary, the Science Report is 

clear that the continuation of bed and banks downstream from disruptions is evidence of the 

surface connection with the channel that is upstream of the perceived disruption. Science Report 

at ES-15. Where breaks in the bed and banks or the OHWM occur due to natural causes, such 

disruptions are associated with changes in the gradient and in the material over and through 

which the water flows. Id. at 2-2. If a disruption in the bed and banks or the OHWM prevented 

connection, the area downstream would lack a bed and banks or OHWM, be colonized with 

terrestrial vegetation, and be indiscernible from the nearby land. Id. The concentrated 
Clean Water Rule Response to Comments – Topic 8: Tributaries

481

longitudinal movement of water and sediment through these channels lowers local elevation, 

prevents soil development, selectively transports and stores sediment, and hampers the 

colonization and persistence of terrestrial vegetation. This approach will simplify 

implementation of the final rule. There is no limit on the length of the break so long as both bed 

band and OHWM can be detected upstream of the break. The clarification and simplification 

provided by the final rule will make it easier – not harder – for farmers and ranchers to determine 

if bed and banks and OHWM can be detected upstream. If bed and banks and OHWM can be 

detected upstream the water body continues to be a covered tributary. In addition, normal 

farming and ranching practices have always been exempt and continue to be exempt from 404 

permitting which should alleviate much of the concern expressed by the commenters.

A number of commenters stated that the longer the break in OHWM, the less likely the feature is 

to contribute flow, and asked for confirmation that if a feature ultimately does not contribute 

flow to any downstream water, such feature would not be categorically included as a 

jurisdictional tributary.

The final rule definition makes clear that a water is considered tributary if it contributes flow, 

either directly or through another water, to a traditional navigable water, interstate water, or the 

territorial seas, and that the water has the physical indicators of a bed and banks and an ordinary 

high water mark. These physical indicators demonstrate there is volume, frequency and duration 

of flow sufficient to create a bed and banks and an ordinary high water mark, and thus to qualify 

as a tributary. If a water does not contribute flow, either directly or through another water, to a 

traditional navigable water, interstate water, or the territorial seas, such water does not qualify as 

a tributary. Site specific conditions will continue to determine the distance up valley that needs 

to be evaluated to see if the break in bed and banks and OHWM is temporary or the start of the 

stream system. These conditions include the size of the stream (larger streams require looking 

further up valley) and the nature of the break (look to see the up valley end of manmade breaks, 

streams buried by colluvium and valley bottom alluvial fans). Conversely, where the bed and 

banks and OHWM simply fade away or abruptly end at a headcut and the substrate, land use and 

valley characteristics do not change above and below the break, minimal up valley evaluation is 

necessary. The time it takes for water to make the connection between the waters above and 

below a break in OHWM will continue to be considered when evaluating breaks in OHWM and 

is largely dependent on the nature of the break. While there has never been a time limit on 

connections, times much longer than would occur if the break was not present point to the 

presence of distinct waterbodies instead of a single waterbody. 

Issue: Break in OHWM should sever jurisdiction

Many commenters stated that natural or man-made breaks in OHWM should sever jurisdiction of 

the water as a tributary. A number commenter’s sought clarification of how the tributary will be 

characterized within the reach of the break in OHWM. Some commenters felt that the area 

within the reach of the break in OHWM should not be considered jurisdictional, while others 

stated that the area within the reach of break in OHWM should be considered jurisdictional.

A number commenters stated that breaks in OHWM are common in ephemeral systems such that 

there may not be a true connection between upstream and downstream features. Many 

commenters stated that a break in OHWM severs connectivity and should require a significant 
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482

nexus analysis instead of categorical inclusion of the feature water as jurisdictional tributary. 

Other commenters stated that a break in OHWM that results in the lack an observable hydrologic 

connection should render the feature as not being categorically included as a jurisdictional 

tributary.

The rule’s definition of “tributary” retains many elements from the proposed rule, but reflects 

public comments in several important ways. In particular, the final rule emphasizes the 

importance of flow. The rule definition of “tributary” requires that flow must be of sufficient 

volume, frequency, and duration to create the physical characteristics of bed and banks and an 

OHWM. If a water lacks sufficient flow to create such characteristics, it is not considered 

“tributary” under this rule. To further emphasize this point, the final rule expressly indicates in 

paragraph (b) that ephemeral reaches that do not meet the definition of tributary are not “waters 

of the United States.” The agencies have concluded that flow of a sufficient volume, frequency, 

and duration create and maintain the physical characteristics of tributaries, such as bed and banks 

and another indicator of OHWM. The agencies have also determined that the presence of 

sufficient flow to form bed and banks and another indicator of OHWM is also sufficient to 

support status as a similarly situated class of waters. The Science Report supports the scientific 

conclusion that all features that meet this definition of tributary, including ephemeral streams,

impact the physical, chemical, and biological integrity of downstream waters and therefore have 

a significant nexus to (a)(1) through (3) waters. See also the summary responses in Section 9 

“Scientific Evidence Supporting the Rule” of the Response to Comments.

As noted by the SAB, and consistent with the scientific literature, tributaries as a group exert 

strong influence on the chemical, physical, and biological integrity of downstream waters, even 

though the degree of connectivity is a function of variation in the frequency, duration, 

magnitude, predictability, and consequences of chemical, physical, and biological processes. See,

e.g., SAB 2014b. These significant effects on traditional navigable waters, interstate waters and 

the territorial seas occur even when the tributary is small, intermittent, or ephemeral. The 

presence of OHWM above a break in the OHWM indicates that a tributary does contribute flow 

to a downstream water, and the Science Report suggests there is a more than insubstantial 

relationship with downstream TNWs. Thus, because a covered tributary – regardless of a break 

in OHWM - does contribute flow to a downstream water, and there is a more than insubstantial 

relationship with downstream TNWs, the area within the break in OHWM is considered 

jurisdictional and is part of a covered tributary. For a further discussion of the limits of CWA 

jurisdiction in regards to tributaries and the use of OHWM see the responses 8.1 and 8.1.2 and 

the TSD.

Because the Agencies based their significant affect / significant nexus determination for covered 

tributaries in part on the amount of flow indicated where a tributary had both a bed banks and 

another indicator of OHWM, the final rule continues to require both physical indicators. The 

Agencies believe that a break in OHWM does not sever connectivity. The CWA regulates and 

controls pollution at its source, in part because most pollutants do not remain at the site of the 

discharge, but instead flow and are washed downstream through the tributary system – regardless 

of a break in OHWM - to endanger drinking water supplies, fisheries, and recreation areas. These 

fundamental facts about the movement of pollutants and the interconnected nature of the 

tributary system demonstrate why covered tributaries of traditional navigable waters, interstate 
Clean Water Rule Response to Comments – Topic 8: Tributaries

483

waters, and the territorial seas, alone or in combination with other covered tributaries in a 

watershed, have a significant nexus with those downstream waters. See also the summary 

responses in Section 9 “Scientific Evidence Supporting the Rule” of the Response to Comments. 

Thus, in the final rule the Agencies assert CWA jurisdiction over all covered tributaries as 

defined. Those covered tributaries are “waters of the United States” without the need for further 

significant nexus analysis above the break in OHWM.

As discussed in the previous section on the length of breaks in OHWM, the agencies will 

continue making case by case determinations of the length of break in OHWM that does not 

sever the connection to downstream waters. Site specific conditions will continue to determine 

the distance up valley that needs to be evaluated to see if the break in bed and banks and OHWM 

is temporary or the start of the stream system. These conditions include the size of the stream 

(larger streams require looking further up valley) and the nature of the break (look to see the up 

valley end of manmade breaks, streams buried by colluvium and valley bottom alluvial fans). 

Conversely, where the bed and banks and OHWM simply fade away or abruptly end at a headcut 

and the substrate, land use and valley characteristics do not change above and below the break, 

minimal up valley evaluation is necessary. As discussed in the prior section on general 

comments, the final rule also does not change the longstanding practice that if there is a break in 

OHWM where the water flows underground without a surface expression of flow path, the 

portion of the flow path that is underground is not jurisdictional. 

Specific Comments

U.S. House of Representatives Committee on Space, Science and Technology (Doc. #16386)

8.343 Your definition of tributary includes water that disappears underground in a so-called 

"natural break."

a. How will the Corps and EPA decide if an upstream channel before a break is the same 

as a downstream channel after a break?

b. Does either distance or timing matter?

c. Does it matter how far or how long water has to flow underground to be considered all 

part of the same tributary system when it recharges surface water somewhere 

downstream, sometime later? (p. 16)

Agency Response: The agencies will continue to use their best professional 

judgment in the field to determine the connection between the up valley channel and 

the down valley channel around breaks in OHWM. These decisions are based on 

site specific conditions and the factors to evaluate vary based on the conditions, e.g. 

karst landscape may require the use tracers, while a break due to a valley bottom 

alluvial fan in the arid west could be evaluated visually. See summary response 

above on Difficulties in determining OHWM, length of break, and contribution of 

flow for discussion of distance and time. 

North Carolina Department of Environment and Natural Resources (Doc. #14984)

8.344 Deletion of the sentence in the definition of "tributary" which says "[a] water that 

otherwise qualifies as a tributary under this definition ... so long as a bed and bank and an 
Clean Water Rule Response to Comments – Topic 8: Tributaries

484

ordinary high water mark can be identified upstream of the break," because inclusion of 

such "tributaries" ignores the nature of the break and the effect of such break on the 

significance of the nexus of the tributary to navigable waters. In essence, the rule assumes 

a significant nexus notwithstanding the nature of the break. 33 CFR 328.3(c)(5), 

40CFRl10.1(3)(v), 40 CFR 112.2(3)(v), 40 CFR 116.3(3)(v), 40 CFR 117. l(i)(3)(v), and 

40 CFR 122.2(c)(5);

... (p. 7)

Agency Response: See summary response 8.3 above on Break in OHWM should 

sever jurisdiction.

San Carlos Apache Tribe (Doc. #15067)

8.345 Features that would otherwise meet the definition of tributary do not lose that status if, 

for any length, there are natural or manmade breaks, provided that there is an ordinary 

high water mark upstream of the break. The proposed rule’s definition of tributaries 

would add a large number of previously unregulated water features to those considered 

tributaries to traditional navigable waters. (p. 4)

Agency Response: See summary response 8.3 above on General Comments 

Opposing and Supporting Approach to Break in OHWM.

Ohio Department of Natural Resources et al. (Doc. #15421)

8.346 The proposed rule asserts jurisdiction over tributaries when there are breaks (natural or 

manmade) in the OHWM along the tributary. The rule discussion states, "A water that 

otherwise qualifies as a tributary under this definition does not lose Its status as a 

tributary if, for any length, there are one or more man-made breaks (such as bridges, 

culverts, pipes, or dams), or one or more natural breaks (such as wetlands at the head of 

or along the run of a stream, debris piles, boulder fields, or a stream that flows 

underground) so long as a bed and banks and an ordinary high water mark can be 

identified upstream of the break." This would allow the USACE and USEPA to take 

jurisdiction on tributaries that would currently be considered isolated and in cases where 

there may be no visible connection to a water included in (a)(l) to (a)(3). For example, a 

small stream entering a sinkhole into fractured bedrock, or into an abandoned coal mine 

subsidence portal, is currently considered an isolated stream if there is no known or 

discernable outlet to a tributary to a downstream water body. By the proposed rule

Indicating that the water only needs to have a bed, bank, and OHWM "upstream" of the 

break, the need to show connectivity has been discounted. From the way the proposed 

rule is worded, it would have to be assumed that a portion of the groundwater discharging 

to nearby tributaries would be coming from the stream that had entered the fractured 

bedrock or mine opening, and therefore the small stream would be jurisdictional 

upstream of where It enters the ground. This change would increase the USACE's and 

USEPA's jurisdiction on waters that are currently considered isolated and not subject to 

federal jurisdiction.

In addition to a rule change resulting in the EPA and Corps taking jurisdiction on waters 

that would not be considered jurisdictional under the current rule, the proposed rule fails 

to discuss the jurisdictional nature of the tributary as it flows through the location of the 
Clean Water Rule Response to Comments – Topic 8: Tributaries

485

"break" in the OHWM, bed, or banks. For some of the "breaks" mentioned In the 

proposed definition (such as bridges, culverts, pipes, dams, and run of stream wetlands) it 

would be obvious where the tributary is located and where It is flowing to, and there will 

be little doubt that the tributary remains jurisdictional throughout the reach that it flows 

through the "break." Often these types of "breaks" have a clearly define channel 

downstream of the "break." However, in the examples of "debris piles, boulder fields, or 

a stream that flows underground" evidence of connectivity to downstream tributaries can 

be much less obvious or non-existent. Would a stream or tributary that flows interstitially 

through a boulder field, dissipates into a sandy floodplain, or that flows underground 

remain a federally jurisdictional water throughout the reach of these types of "break" 

despite the lack of bed, bank, and OHWM? Or, would it only be jurisdiction in areas 

where it possesses a bed, bank and OHWM? If it continued to remain jurisdictional in 

subsurface situations, how would a regulator or an applicant determine the location of the 

tributary? How would they determine potential impacts or fill quantities if the water is 

jurisdictional throughout these "breaks"?

While it is likely that tributaries that possess "breaks" in their bed, bank, and OHWM do 

have a significant nexus to a downstream water body, and ODOT is not opposed to 

including tributaries with these types of "breaks" as jurisdictional waters, we do believe 

that greater clarification is needed on how the tributaries will be characterized within the 

reach of the "break". Decisions made in this proposed rule change will have real world 

implications on 404 and 401 permitting that must be considered before implementation. 

(p. 8-9)

Agency Response: The termination of an OHWM and bed and banks into a 

underground mine works and other subsurface works that do not have a clear 

reemergence continuing the stream system on the surface does not qualify as a 

break in OHWM. See summary response 8.3 above on General Comments 

Opposing and Supporting Approach to Break in OHWM and Break in OHWM 

should sever jurisdiction for response to other issues raised. 

California Department of Transportation, Division of Environmental Analysis (Doc. #19538)

8.347 10) The proposed definition for tributaries states that "A water that otherwise qualifies as 

a tributary under this definition does not lose its status as a tributary if, for any length, 

there are one or more man-made breaks (such as bridges, culverts, pipes, or dams), or one 

or more natural breaks (such as wetlands at the head of or along the run of a stream, 

debris piles, boulder fields, or a stream that flows underground) so long as the bed and 

banks and an ordinary high water mark can be identified upstream of the bank." We 

request that this definition be changed to include a reasonable limit to the length of a 

natural break. The absence of a limit to the length of a natural break could lead to 

additional information requests and surveys that could unnecessarily delay the 

jurisdictional delineation verification process and ultimately projects. We recommend 

that language be added to limit the length of any break in ordinary high water mark 

(OHWM) to be easily identifiable upstream and downstream and that break size be 

appropriate to the size of the tributary. Additionally, Caltrans requests that you clarify 

that the underground portion of a tributary is groundwater and would be excluded from 

jurisdiction. (p. 3)
Clean Water Rule Response to Comments – Topic 8: Tributaries

486

Agency Response: See summary response 8.3 above on General Comments 

Opposing and Supporting Approach to Break in OHWM and Break in OHWM 

should sever jurisdiction. 

Western Coalition of Arid States (Doc. #14407)

8.348 The agencies also state that any man-altered natural streams, or man-made conveyances, 

that meet the definition of a tributary, do not lose their status as jurisdictional waters. The 

agencies, however, do not discuss anywhere in the rule’s preamble, in Appendix A to the 

preamble, or the Connectivity Report, the science that supports this decision. Allowing 

for categorical jurisdiction of all man-altered streams or man-made conveyances, 

regardless of breaks, or conversions, and that lack a scientific chemical, physical, or 

biological connection, expands the concept of jurisdictional tributary beyond reason. The 

proposed definition of tributary will significantly affect the manner in which WESTCAS 

members construct, maintain and operate our critical water infrastructure. (p. 10)

Agency Response: See summary response 8.3 above on General Comments 

Opposing and Supporting Approach to Break in OHWM and TSD sections 7.B.5 

and 7.C. 

Flood Control and Water Conservation District, Riverside County, California (Doc. #14581)

8.349 ...the length of natural "breaks" through ponds, lakes, and wetlands, should not matter as 

long as the flows stay on the surface. However, once flows go underground, or dry up, 

that is a real break in the jurisdictional chain, and what matters then for determining 

waters of the United States jurisdiction should be the frequency of the physical 

connection of surface waters. (p. 5)

Agency Response: See summary response 8.3 above on Break in OHWM should 

sever jurisdiction. 

City of Buckeye, Arizona (Doc. #14591)

8.350 7. The definition for the term "tributary" provided in the proposed draft rule language is 

breathtakingly broad, especially the language related to man-made and natural breaks. 

Under this language, it appears that many urban SCMs could be considered tributary to 

other Waters of the United States and, thus, themselves be WOTUS. This contradicts 

EPA's public statements that most urban SCMs are not WOTUS. Broad inclusion 

language and reliance on agency best professional judgment and discretion regarding the 

WOTUS status of most urban SCMs and BMPs are not acceptable or practicable. (p. 3)

Agency Response: See response to comments summary for section 7.4. and the 

additional clarity provided in the final rule by specifically excluding certain 

stormwater features from the definition of “waters of the United States” in (b)(6). 

American Foundry Society (Doc. #15148)

8.351 The agencies justify this effort to broaden the boundaries of what the agencies consider a 

tributary because in “some regions of the country where there is a very low gradient, the 

banks of a tributary may be very low or may even disappear at times.” 79 Fed. Reg. at 
Clean Water Rule Response to Comments – Topic 8: Tributaries

487

22202. This appears to be a thinly veiled justification to protect human health and the 

environment, without first demonstrating any harm that must be eliminated or prevented.

This uncertainty and potential liability is further aggravated by the EPA and the Corps 

determination that “[a] water that otherwise qualifies as a tributary under the proposed 

definition does not lose its status as a tributary if, for any length, there are one or more 

man-made breaks (such as bridges, culverts, pipes, or dams), or one or more natural 

breaks (such as debris piles, boulder fields, or a stream segment that flows underground) 

so long as a bed and banks and an ordinary high water mark can be identified upstream of 

the break.” How far would a landowner have to look “upstream” to insure he or she is not 

liable for routine activities in an area that may lack a bed, bank, or OHWM, yet is still 

considered a jurisdictional water?

In many intermittent and ephemeral tributaries, including dry-land systems in the arid and 

semi-arid west, OHWM indicators can be discontinuous within an individual tributary 

due to the variability in hydrologic and climatic influences. 79 Fed. Reg. at 22202. 

Furthermore, specific areas of arid land drainage (e.g., alluvial fans) experience random 

channel breaks or avulsions in heavy precipitation events, the presence of an upstream 

channel (i.e., at the head of the fan) could then render the entire region an ephemeral 

streambed subject to regulation. Accordingly, how does a landowner gauge liability for 

CWA violations of $37,500 per day per occurrence and the risk of a citizen law suit when 

the discernable features of a tributary may not exist in a specific location? It is difficult to 

understand how the agencies consider it logical that the proposed rule provides clarity 

and certainty for industrial operations. (p. 5-6)

Agency Response: See summary response above on General Comments Opposing 

and Supporting Approach to Break in OHWM and Break in OHWM should sever 

jurisdiction. 

Federal StormWater Association (Doc. #15161)

8.352 The proposed rule asserts jurisdiction over all “tributaries” of navigable or interstate 

water or territorial seas or impoundments thereof. Tributaries are jurisdictional under the 

current regulatory definition of waters of the U.S. 33 CFR § 328.3(a)(5). However, the 

term “tributaries” is not currently defined. The proposed rule expands jurisdiction over 

this category of water by proposing to define tributaries to include features on the land 

where an EPA or Corps employee believes he or she can discern a bed, bank, and 

ordinary high water mark (OHWM), even if these features disappear underground, as 

long as these features can be identified upstream of where they disappear.530 This 

proposed expansion of the definition of “tributary” has created tremendous uncertainty 

regarding the status of land that exhibits erosion features from wind or water even if dry 

for many years, the status of water conveyance systems, the status of water drainage 

 

530 “A water that otherwise qualifies as a tributary under this definition does not lose its status as a tributary if, for 

any length, there are one or more man-made breaks (such as bridges, culverts, pipes, or dams), or one or more 

natural breaks (such as wetlands at the head of or along the run of a stream, debris piles, boulder fields, or a stream 

that flows underground) so long as a bed and banks and an ordinary high water mark can be identified upstream of 

the break.” Proposed 33 CFR § 328.3(c)(5).
Clean Water Rule Response to Comments – Topic 8: Tributaries

488

systems, and the status of ephemeral streams that have no continuous surface connection 

to navigable water. (p. 3-4)

Agency Response: See summary response 8.3 above on General Comments 

Opposing and Supporting Approach to Break in OHWM and Break in OHWM 

should sever jurisdiction. 

Water Advocacy Coalition (Doc. #17921.1)

8.353 Finally, waters should not be considered tributaries regardless of manmade and natural 

breaks “for any length.” The GEI Report notes that “the science does not support the 

Agencies’ assertion that a significant nexus between a tributary and a traditional 

navigable water is not broken where the tributary flows through a culvert or other 

structure.” Moreover, the SAB Panel noted that the Connectivity Report lacked sufficient 

information on the influence of human alterations on connectivity and “generally 

exclude[d] the many studies that have been conducted in human-modified stream 

ecosystems.” Such breaks can sever connectivity, even when a channel can be identified 

upstream. Dr. Mark Murphy points out that such categorical jurisdiction regardless of 

breaks is not scientifically justified, stating that “OHWM indicators are discontinuous 

because flow paths are discontinuous and connectivity across them can drop to a nearzero significance.” As the preamble notes, for example, dams cut off flow and store 

water for any number of reasons, such as flood control, irrigation water supply, and 

energy generation. See 79 Fed. Reg. at 22,235. It is quite a leap for the agencies to 

determine that the waters behind such dams categorically have significant physical, 

chemical, and biological effects on downstream traditional navigable waters. Allowing 

for per se jurisdiction regardless of breaks for any length expands the concept of 

“tributary” beyond what the science supports and would include intrastate waters that 

lack meaningful connection to traditional navigable waters. (p. 46-47)

Agency Response: See summary response 8.3 above on General Comments 

Opposing and Supporting Approach to Break in OHWM and Break in OHWM 

should sever jurisdiction and TSD sections 2.A, 7.B.5 and 7.C. 

Kerr Environmental Services Corp. (Doc. #7937.1)

8.354 The proposed definition of tributary already has an accurate and sufficient clause 

allowing for both man-made and natural "breaks" in of bed and bank and OHWM. We 

believe this latter section should be retained. This section reads:

"A water that otherwise qualifies as a tributary under this definition does not lose its 

status as a tributary if, for any length, there are one or more man-made breaks... , or 

one or more natural breaks (such as wetlands at the head of or along the run of a 

stream, debris piles, boulder fields, or a stream that flows underground) so long as a 

bed and banks and an ordinary high water mark can be identified upstream of the 

break."

By this definition, only those wetlands interspersed along the length or at the tributary's 

head are considered a part of the tributary. We believe this to be the appropriate and only 

reference to wetlands needed in the definition of tributary. (p. 9)
Clean Water Rule Response to Comments – Topic 8: Tributaries

489

Agency Response: The final rule retains much of the language supported in the 

above comment. Minor changes were made to account for the change in status of 

wetlands and other features without an OHWM from tributaries to adjacent waters. 

The final language is: 

A water that otherwise qualifies as a tributary under this definition does not 

lose its status as a tributary if, for any length, there are one or more 

constructed breaks (such as bridges, culverts, pipes, or dams), or one or more 

natural breaks (such as wetlands along the run of a stream, debris piles, 

boulder fields, or a stream that flows underground) so long as a bed and 

banks and an ordinary high water mark can be identified upstream of the 

break.

El Dorado Holdings, Inc. (Doc. #14285)

8.355 Interruptions in an OHWM also are common in ephemeral systems. Pursuant to the 

proposal (33 C.F.R. § 328.3(c)(5)), such an interruption does not foreclose a tributary 

relationship so long as a bed and banks and an ordinary high water mark can be identified 

upstream of the break. In some cases, there may be a relatively clear connection between 

upstream and downstream portions of the same tributary despite intervening absence of 

an OHWM (e.g., where water is conveyed briefly through a culvert). In other cases, 

however, the connection may be less clear or nonexistent. One such example is a small 

channel on relatively steep slopes that subsequently enters a flat area and essentially 

dissipates as a defined channel. There may be other channels with what the agencies 

consider to be an OHWM downstream of the point where the original channel dissipates, 

but there may not be any true connection between the upstream and downstream features. 

In such a case, the channel that dissipates should not be considered part of a regulated 

tributary, but it is not clear if this would be the case under the proposal. The agencies 

could resolve this uncertainty in at least two fashions: (1) clarify that in such a situation, 

the feature that dissipates qualifies as an exempt gully or rill and not part of a tributary; or 

(2) incorporate language into the “tributary” definition similar to that used in the Corps’ 

current approved jurisdictional determination form,531 which states (in footnote 6) that a 

break in OHWM “that is unrelated to the waterbody’s flow regime (e.g., flow over a rock 

culvert or through a culvert)” does not necessarily sever jurisdiction above the break 

(emphasis added).

Another factor that is not clearly considered in the proposal, but that is especially 

pertinent in arid environments, is transmission losses. One may be able to trace a line on 

a map that connects a distant headwater ephemeral wash to a downstream TNW, but in 

reality water from the wash may have little or no potential of reaching the downstream 

water in any realistic scenario. For example, at the Silver Bell Mine (discussed below), an 

applicant provided information showing that even in a 100-year, 24-hour storm event, 

water in headwater ephemeral washes would only travel an estimated 12.9 miles from the 

mine. The nearest TNW in that case was over 100 miles away. In a situation such as that, 

 

531 Available at:

http://www.spl.usace.army.mil/Portals/17/docs/regulatory/JD/AJD/Approved_JD_Form.doc
Clean Water Rule Response to Comments – Topic 8: Tributaries

490

the headwater wash has no realistic chance of contributing flow to the TNW, and should 

not be considered a tributary that is automatically regulated.

Recommendation: (1) The agencies should establish some objective standard for 

determining when a water “contributes flow” to a downstream TNW. For example, the 

agencies could establish a minimum storm event and state that if a wash or portion 

thereof would not have a hydrologic connection with a downstream TNW or interstate 

water during that event, it would not be considered a regulated tributary. (2) The agencies 

also should clarify that where there are natural breaks in OHWM based on a water’s flow 

regime (e.g., flow being so infrequent and/or minor that a defined channel disappears), 

areas upstream of such breaks are not automatically regulated as tributaries. (p. 14-15)

Agency Response: See summary response 8.3 above on General Comments 

Opposing and Supporting Approach to Break in OHWM and Break in OHWM 

should sever jurisdiction. In addition, case specific determinations of jurisdiction 

are beyond the scope of this rulemaking effort.

8.356 6. Ignoring the existence of dams, diversions or obstructions may result in regulation of 

portions of waters with no significant nexus to downstream TNWs: The proposed 

definition of “tributary” provides that a break (such as a dam) does not alter the status of 

the water as a regulated tributary so long as there is an identifiable OHWM and bed and 

banks located upstream of the break (e.g., the dam). However, in the arid West, waters 

upstream of at least some dams, diversions or similar obstructions (depending on their 

design and purpose) may be effectively precluded from having a physical, chemical or 

biological effect on a downstream TNW (or any such remaining effect may be severely 

limited). If a dam impounded all flow and never discharged, the upstream waters 

presumably would not qualify as tributaries because they would not “contribute flow” to 

any downstream water. However, if the dam had ever discharged, or even if it just had 

the potential to discharge (e.g., a spillway included in the design), it presumably would be 

regulated as a tributary under the proposal. In that latter case, the proposal would result in 

the regulation of waters with at best a speculative or insubstantial effect on downstream 

TNWs, despite Justice Kennedy’s conclusion that such waters should not be regulated 

because they do not possess a significant nexus with downstream TNWs.

Another similar example can be seen in the mining industry, where ephemeral washes 

have often been truncated through construction of large features (pits, rock piles, tailings 

piles, etc.). Such construction often occurred pre-Clean Water Act; more recently, it 

would have been done under the authorization of a Section 404 permit. In some cases, the 

upstream portions of the washes are diverted around the feature and thus maintain a 

relationship with downstream washes; in others, however, the upstream washes are not 

diverted, and instead are merely truncated. A good example would be ephemeral washes 

that have been cut off by a pit. In this situation, the truncated wash may still have what 

the Corps considers to be an OHWM, but there is obviously zero chance that it will 

contribute flow to any downstream water. We presume that in such cases the upstream 

wash would not be a tributary because there is zero chance that it “contributes flow” to a 

downstream water, but it would be helpful if the agencies clarified this point in any final 

rule.
Clean Water Rule Response to Comments – Topic 8: Tributaries

491

Recommendation: (a) The agencies should remove the categorical statement that 

presence of an OHWM and bed and banks above a dam or diversion is sufficient to assert 

jurisdiction, or otherwise clarify that the “contribute flow” requirement may not be met in 

the case of all dams or diversions (in which case the upstream channels would not be 

considered tributaries under the proposed rule); (b) the agencies also should clarify that 

waters completely truncated by man-made features (including but not limited to those at 

mining sites), such that there is no longer a connection to downstream waters, are no 

longer considered tributaries because they have no potential to “contribute flow” to other 

waters. (p. 17-18)

Agency Response: The final rule continues the agencies’ longstanding regulation 

of impoundments of waters that would otherwise be waters of the U.S., see (a)(4). 

Manmade structures that impound waters of the U.S. do not sever the jurisdiction 

of the upstream waters. 

National Association of Home Builders (Doc. #19540)

8.357 4. The Agencies’ Treatment of “Breaks” along Tributaries is Inconsistent with 

Science and Existing Policy.

The proposed rule states that a water does not lose its status as a tributary – and thus 

jurisdiction by rule – if “for any length, there are one or more man-made breaks . . . or 

one or more natural breaks . . . so long as a bed, and banks, and an ordinary high water 

mark can be identified upstream of the break.”532 However, in preserving a water’s 

“tributary” status regardless of the length of any number of man-made and/or natural 

breaks, the Agencies fail to recognize what their colleagues in EPA’s Office of Research 

and Development acknowledge in the draft Connectivity Report, that is, the larger a 

break, the less likely a “tributary” is to contribute flow to a downstream traditional 

navigable water. Moreover, the contribution of flow from a “tributary” to a downstream 

water will become increasingly more difficult to quantify as the length of a break or 

multiple breaks increases.

Further, the proposed rule’s interpretation that a tributary retains its tributary status 

regardless of the length of a break or breaks along its length would expand categorical 

jurisdiction beyond tributaries considered jurisdictional under existing guidance. The 

2008 Rapanos Guidance states, “[a] non-navigable tributary of a traditional navigable 

water is a non-navigable water body whose waters flow into a traditional navigable water 

either directly or indirectly by means of other tributaries.”533 Indeed, under current 

guidance, flow from a non-navigable tributary must flow into a traditional navigable 

water either directly or through other tributaries. There is no mention of indirect flow 

through non-tributaries in the existing guidance, yet the proposed rule would permit 

indirect contribution of flow from tributaries through non-tributary features for a water to 

meet the categorically jurisdictional tributary definition.

The treatment of breaks is also inconsistent with language in the preamble in which the 

Agencies assert that “tributary streams, including perennial, intermittent, and ephemeral 

 

532 79 Fed. Reg. at 22,263 (emphasis added)

533 2008 Rapanos Guidance at 6 (emphasis added).
Clean Water Rule Response to Comments – Topic 8: Tributaries

492

streams, and certain categories of ditches are integral parts of river networks because they 

are directly connected to rivers via permanent surface features (channels and associated 

alluvial deposits) . . .”534 This statement contradicts the tributary definition that expressly 

includes flow paths that are not permanent or direct.

The Agencies must remove the language pertaining to “breaks” from the tributary 

definition as it is inconsistent with science, existing policy, and preamble language. (p. 

62-63)

Agency Response: See summary response 8.3 above on General Comments 

Opposing and Supporting Approach to Break in OHWM for clarification of how 

breaks in OHWM were addressed under the 2008 guidance. See summary response 

8.3 above e on Difficulties in determining OHWM, length of break, and contribution 

of flow; and Break in OHWM should sever jurisdiction for clarification of practice 

and rationale for looking upstream of breaks in OHWM. 

Pennsylvania Coal Alliance (Doc. #13074)

8.358 ...Although not an exhaustive listing, the following types of questions would remain if 

the Proposed Rule is finalized, as currently written:

...f. Tributary – If a “break” occurs in the tributary, is the area of the “break” considered 

to be jurisdictional? Asserting that a tributary still exists when there is a “break” or no 

bed, bank and OHWM obscures the “bright line” categories of jurisdictional waters that 

the Proposed Rule reportedly tries to introduce to simplify the jurisdictional 

determination process. (p. 15)

Agency Response: See summary response 8.3 above on General Comments 

Opposing and Supporting Approach to Break in OHWM. 

National Stone, Sand and Gravel Association (Doc. #14412)

8.359 NSSGA requests that EPA and the Corps withdraw the proposed rule as fundamentally 

flawed. Any future rule should include consultation with businesses and the states and

incorporate the following recommendations described in more detail...

...

Revise the definition of "tributary" to clarify that a water loses its tributary status, if for 

any portion of its length there are one or more man-made brakes (such as bridges, 

culverts, pipes, dams or roads). In order to establish jurisdiction, the agencies would have 

to provide site specific evidence that, under normal circumstances, water would likely 

move from one side of the break along with evidence of a continuous Ordinary High 

Water Mark (OHWM) (or bed and banks) on the opposite side of the break and would 

provide documented ecological benefits to the closest TNW. (p. 8, 9)

Agency Response: See summary response 8.3 above on Break in OHWM should 

sever jurisdiction. 

 

534 79 Fed. Reg. at 22,227 (emphasis added).
Clean Water Rule Response to Comments – Topic 8: Tributaries

493

Halliburton Energy Services, Inc. (Doc. #15509)

8.360 ... the proposed definition specifies that a water that otherwise qualifies as a tributary 

under the definition "does not lose its status as a tributary if, for any length, there are one 

or more man-made breaks (such as bridges, culverts, pipes, or dams), or one or more 

natural breaks (such as wetlands at the head of or along the run of a stream, debris, piles, 

boulder fields, or a stream that flows underground) so long as a bed and banks and an 

ordinary high water mark can be identified upstream of the break." Examples of 

tributaries with breaks include dry-land systems in the arid and semi-arid west that may 

have stretches which flow through low gradient areas and do not exhibit an ordinary 

high-water mark, or a tributary that loses its bed and banks over a stretch characterized by 

wetlands. (p. 3)

Agency Response: No response required. 

Alpha Natural Resources, Inc. (Doc. #15624)

8.361 I. DISRUPTED STREAMS WITHOUT OBSERVABLE HYDROLOGICAL 

CONNECTIONS TO DOWNSTREAM WATERS ARE NOT “TRIBUTARIES”

Alpha encourages the agencies to clarify that streams with intervening natural or manmade breaks or disturbances that cause the streams to have no observable hydrologic 

connection to downstream waters do not satisfy the definition of “tributaries” because 

they lack a significant nexus to downstream navigable waters. Instead, disrupted streams 

with no observable hydrologic connection to downstream waters should be deemed nonjurisdictional.

...

...intervening natural or man-made breaks or disturbances sometimes completely sever 

all observable hydrologic connections between a stream with a defined bed and banks 

and an ordinary high water mark and downstream navigable waters. While these 

disrupted water segments have many of the features of streams, they do not satisfy the 

definition of “tributaries” because they do not contribute flow to downstream navigable 

waters.

A stream’s hydrologic connection with downstream waters can be severed in many ways. 

For example:

 Streams can be buried for thousands of feet when large quantities of rock and dirt 

are moved from mountainous terrain to nearby valleys during the construction of 

public highways;

 Changes to geography and geology in mountainous terrain can cause changes to 

flow regimes that turn streams that once carried water into dry relic stream beds;

 Streams can flow into abandoned underground mine works or into naturally 

occurring underground caverns and become losing streams that lack observable 

hydrologic connections to downstream navigable waters;
Clean Water Rule Response to Comments – Topic 8: Tributaries

494

 Stream segments in higher elevations can be cut-off and isolated from 

downstream waters by pre-law535 coal mining benches and highwalls; and

 Stream segments can become isolated from downstream navigable waters by the 

lawful filling of jurisdictional waters through slurry impoundments.

The streams described above that lack observable hydrologic connections to downstream 

waters are distinguishable from the tributaries described in the proposed rule where 

culverts or dams disrupt—but do not sever—the hydrologic connection between stream 

segments above and below the break. See 79 Fed. Reg. 22,201-02 and 22,235.

The preamble acknowledges that streams without observable hydrologic connections to 

downstream waters, such as “losing streams and other streams that cease to flow before

reaching the downstream . . . waters” “are not part of the tributary system” and should be 

assessed on a case-by-case basis as “other waters.” Id. at 22,250. EPA’s draft536

Connectivity Report537 also verifies the existence of streams that are disconnected from 

downstream waters and therefore cannot be deemed to categorically jurisdictional.

Unidirectional wetlands that do not connect to the river network through surface 

water include wetlands that spill into losing streams that are completely 

disconnected from the river network (i.e., the wetland exports water through an 

output channel but the water is completely lost before it reaches the river network 

due to evapotranspiration or loss to groundwater).

Draft Connectivity Report, p. 5-40.

The Science Advisory Board (“SAB”), in its August 11, 2014 draft review538 of EPA’s 

Draft Connectivity Report, reiterates that hydrologic connectivity can be greatly impacted 

by human activities, thereby providing further support for the notion that disrupted 

streams with no identifiable hydrologic connectivity to downstream waters should not be 

deemed tributaries that are per se jurisdictional. The SAB report criticizes the 

Connectivity Report for failing to adequately address the impacts that human alteration 

can have on connectivity.

 

535 “Pre-law” refers to coal mining activities that occurred before the passage of the Surface Mining Control and 

Reclamation Act of 1977 (“SMCRA”).

536 The agencies’ final rule will be informed by the final version of EPA’s Connectivity Report, which was not 

released before the November 14, 2014 public comment deadline. The draft version that is currently available to the 

public is incomplete and has the warning “DO NOT CITE OR QUOTE” stamped on every page. The ability of the 

public to offer meaningful comments, and the integrity of the public comment process itself, is severely undermined 

when only an unfinished draft of a key document is made available to the public by the close of the comment 

deadline. Alpha respectfully requests that the public comment period be re-opened once EPA releases its final 

Connectivity Report.

537 Connectivity of Streams and Wetlands to Downstream Waters: A Review and Synthesis of the Scientific Evidence, 

EPA/600/R-11/098B (Sept. 2013 Draft).

538 The SAB’s final review of EPA’s Connectivity Report was also not made publicly available during the comment 

period. Given that the agencies have worked on this proposed rule for years since the U.S. Supreme Court’s decision 

in Rapanos, it is unclear why this proposed rule needed to be rushed before EPA finalized its supportive documents 

and the SAB could complete its review of those EPA documents. Alpha respectfully requests that the public 

comment period be re-opened following the release of the SAB’s final review of EPA’s final Connectivity Report.
Clean Water Rule Response to Comments – Topic 8: Tributaries

495

[Human] alterations can be of three types: some can directly decrease 

connectivity, such as dams (Ward and Stanford 1983) and groundwater pumping

that lowers local water tables and causes surface-water connections to cease

(Haag and Pfeiffer 2012).

SAB Report, 8/11/14, pp. 10.

The current version of the report generally excludes the many studies that have 

been conducted in human-modified stream ecosystems. This literature (e.g., Blann 

et al. 2009) should be included in the Report in order to provide information about 

the consequences of alterations of headwater streams to the physical, chemical, 

and biological integrity of downgradient waters. Many headwater stream 

ecosystems are altered by land-use change and human activity that often disrupts 

connectivity. ***The SAB finds that there are many insights to be gained about 

the importance of connectivity to downstream waters when connections are either

severed or enhanced. *** The SAB recommends that the Report authors consider 

including examples from at least some of the following human alterations 

affecting the connectivity of streams: buried streams *** roads.

SAB Report, 8/11/14, pp. 31-32.

The SAB recommends that Section 5.4, as well as other sections of the Report, 

acknowledge these types of alterations or man-made habitats and include a 

discussion of current and past (legacy) human alterations of watersheds and how 

they affect the type, strength, and magnitude of connectivity pathways. In 

particular, human activities such as water diversion or water extraction may 

influence the water table, thereby reducing the potential for connections within 

and among wetlands and downstream waters.

SAB Report, 8/11/14, p. 58.

For the reasons above, Alpha respectfully requests that the agencies clarify that streams 

with no observable hydrologic connections to downstream navigable waters as a result of 

intervening natural or man-made breaks or disruptions are not jurisdictional per se 

“tributaries.” (p. 2, 3-5)

Agency Response: See summary responses above on Break in OHWM should 

sever jurisdiction.

8.362 II. DISRUPTED STREAMS WITHOUT OBSERVABLE HYDROLOGIC 

CONNECTIONS TO DOWNSTREAM WATERS SHOULD RARELY BE 

AGGREGATED

Streams that lack observable hydrologic connections to downstream waters due to 

intervening natural or man-made breaks or disturbances possess unique characteristics, 

most notably the type of disturbance and the length of the break in the hydrologic 

connection. Accordingly, the agencies should clarify that when evaluating the 

connectivity of a disrupted stream that has no observable hydrologic connection to 

downstream waters, the disrupted stream should not be aggregated with streams that may 

have been “similarly situated” to it prior to the disturbance.
Clean Water Rule Response to Comments – Topic 8: Tributaries

496

The preamble explains that when the significant nexus of “other waters” is evaluated, the 

agencies consider whether the “other water,” “alone or in combination with similarly 

situated ‘other waters’ in the region” has a significant nexus to traditional navigable 

waters. 79 Fed. Reg. 22,189. The method by which steams are aggregated can have a 

great impact on significant nexus determinations, because the effect of a single stream on 

downstream waters is often negligible, especially when the stream has no observable 

hydrologic connection to downstream waters. (p. 5-6)

Agency Response: See summary response 8.3 above and TSD sections 2.B and 7. 

Pennsylvania Grade Crude Oil Coalition (Doc. #15773)

8.363 If a "break" occurs in the tributary, is the area of the "break" considered to be 

jurisdictional? Asserting that a tributary still exists when water flows underground, 

through boulders or otherwise without a bed, bank and OHWM only confuses and 

complicates the "bright line" categories of jurisdictional waters reportedly sought by the 

agencies to simplify the jurisdictional determination process. (p. 10)

Agency Response: See summary response 8.3 above on General Comments 

Opposing and Supporting Approach to Break in OHWM. 

Dominion Resources Services, Inc. (Doc. #16338)

8.364 ...To the extent the agencies move forward with the proposal, we make the following 

recommendations:

...

 The proposed rule would consider any feature a tributary regardless of a manmade or natural break of any length. This break could be a dam or long culvert. 

We request that the rule include clarification language to confirm that the 

interrupted portions of a tributary are not jurisdictional. (p. 8)

...

Agency Response: See summary response 8.3 above on General Comments 

Opposing and Supporting Approach to Break in OHWM. 

Pennsylvania Aggregates and Concrete Association (Doc. #16353)

8.365 Establishment of Ephemeral Jurisdiction Should Utilize More Than Just One of the 

Ordinary High Mark Indicators.

The proposed rule for identifying whether a stream is ephemeral permits the Corps field 

personnel to make that determination based on the Ordinary High Water Mark 

(OHWM)539. The use of the OHWM makes it a challenge to define the difference 

between ephemeral streams and erosion-based channels due to conflicting agency 

identifiers and definitions that blur the difference between ephemeral streams and 

erosional channels. The Corps apparently agrees as evidenced by their publishing of the 

recent 2014 guidance. However, the latest guidance does not require the use of a rigorous 

 

539 79 FR 22218.
Clean Water Rule Response to Comments – Topic 8: Tributaries

497

set of conditions or indicators by which to establish jurisdiction, but rather with only 

minimal, or even no primary condition or indicator. This should be changed and the 

jurisdictional limits of ephemeral streams be based on the presence of at least two of the 

three OHWM conditions/indicators. (p. 4-5)

Agency Response: See summary responses above in Section 8.1.2 on the Use of 

OHWM inappropriate/appropriate – will lead to over/under coverage of features. 

Montana Farm Bureau Federation (Doc. #12715)

8.366 Equally unclear is the Agencies' statement that "a tributary is a longitudinal surface 

feature that results from directional surface water movement and sediment dynamics 

demonstrated by the presence of bed and banks, bottom and lateral boundaries, or other 

indicators of [ordinary high water mark]." Id. at 22,202. Even a bed and bank become 

unnecessary to call water a "tributary" because the Agencies have declared that "in some 

regions of the country where there is a very low gradient, the banks of a tributary may be 

very low or may even disappear at times." This example, and countless others, 

demonstrate the extensiveness and subjectivity in the proposed "tributary" definition. The 

proposed rule would regulate activities on land on which water channels and flows when 

it rains, so long as the flowing water leaves a mark on the land. It may even regulate land 

where there is no visible channel. This is precisely why the rule would have such an 

adverse effect on Montana's farmers and ranchers. Keep in mind the previous 

descriptions of the ways water moves over land in times of snowmelt and heavy rain, but 

no other time. If temporary snowmelt, low spots, and places where water runs in times of 

heavy rainfall can be considered "Waters of the United States," many new areas will be 

regulated in Montana. (p. 2)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. As described in the 

summary response responses 8.1 and 8.1.2, the final rule clearly requires the 

presence of both bed and banks and another indicator of OHWM, if one is not 

present then the water does not qualify as a tributary. Wetlands, lakes, ponds, and 

other features lacking a bed and banks and/or OHWM are no longer defined as 

tributaries in the Final Rule, but may be considered jurisdictional “waters of the 

United States” as adjacent waters or similarly situated waters with a significant 

nexus to (a)(1) through (3) waters. See summary responses above in Section 8.1.2 on 

the Use of OHWM inappropriate/appropriate – will lead to over/under coverage of 

features for further discussion of the requirements for tributaries. 

National Chicken Council, National Turkey Federation, and U.S. Poultry & Egg Association 

(Doc. #14469)

8.367 The uncertainty and potential liability associated with implementation of the rule is 

further aggravated by the EPA and the Corps determination that “[a] water that otherwise 

qualifies as a tributary under the proposed definition does not lose its status as a tributary 

if, for any length, there are one or more man-made breaks (such as bridges, culverts, 

pipes, or dams), or one or more natural breaks (such as debris piles, boulder fields, or a 

stream segment that flows underground) so long as a bed and banks and an ordinary high 

water mark can be identified upstream of the break.” 79 Fed. Reg. at 22202. This 
Clean Water Rule Response to Comments – Topic 8: Tributaries

498

determination prompts some practical, but critical questions for implementation of the 

rule. For example, how far will a farmer have to look “upstream” to ensure he is not 

liable for applying fertilizer or pesticide into an area that may lack a bed and a bank and 

an OHWM, yet is still considered a jurisdictional water? The agencies have specifically 

indicated that “[I]n many intermittent and ephemeral tributaries, including dry-land 

systems in the arid and semi-arid west, OHWM indicators can be discontinuous within an 

individual tributary due to the variability in hydrologic and climatic influences.” Id. at 

22202. Consequently, how does a farmer gauge his liability for CWA violations of 

$37,500 per day per occurrence and the risk of a citizen lawsuit when the discernible 

features required for a water to be a “tributary” do not exist in a specific location? It is 

difficult to understand how the agencies consider it logical that the proposed rule 

provides clarity and certainty to poultry and egg producers. (p. 5)

Agency Response: See summary response 8.3 above on Difficulties in determining 

OHWM, length of break, and contribution of flow. 

Charlotte-Mecklenburg Storm Water Services (Doc. #3431)

8.368 ...Regarding man-made and natural breaks, it may be difficult to confirm that a water is 

actually connected to downstream waters especially when streams flow underground. 

These systems may be connected to groundwater on a hill due to erosion, but then 

disappear into a field or flat area with no further evidence of a surface water connection. 

CMSWS recommends...requiring that “bed banks and OHWM be established above and 

below of natural or man-made break” in order to prove connectivity. (p. 3)

Agency Response: The final rule incorporates the commenter’s suggestion and

requires OHWM and bed and banks both above and below natural or manmade 

breaks. 

Duke Energy (Doc. #13029)

8.369 Further, the proposed definition states “[a] water that otherwise qualifies as a tributary 

under this definition does not lose its status as a tributary if, for any length, there are one 

or more man-made breaks (such as bridges, culverts, pipes, or dams), or one or more 

natural breaks (such as wetlands at the head of or along the run of a stream, debris piles, 

boulder fields, or a stream that flows underground), so long as a bed and banks and an 

ordinary high water mark can be identified upstream of the break.” This again is an 

expansion of the traditional concept of a tributary. Moreover, some of these types of 

breaks can sever connectivity, even when a channel can be identified upstream. As the 

preamble notes, for example, dams cut off flow and store water for any number of 

reasons, such as flood control, irrigation water supply, and energy generation. Therefore, 

it is hard to imagine that the agencies can assert categorical jurisdiction for waters behind 

such dams without first demonstrating that they have significant physical, chemical and 

biological effects on the downstream traditional navigable waters and not just “a 

connection.” (p. 23-24)

Agency Response: See summary response 8.3 above on Break in OHWM should 

sever jurisdiction.
Clean Water Rule Response to Comments – Topic 8: Tributaries

499

EcoSynthesis Scientific & Regulatory Services (Doc. #14586)

8.370 In my 25 years of field experience with delineation, where short natural breaks interrupt 

the bed and bank of a tributary, other indicators (such as scouring or sorting of substrate 

to a coarser texture than prevails in adjoining uplands) show that the flow is indeed 

continuous. If the flow is so rare (as in, probably not occurring except in 10- or 20-year 

return interval events) that no evidence of surface flow (or indeed actual negative 

evidence such as leaf debris carried out onto the landscape and left there in a widely 

distributed layer, with no central debris-free flow line), then this feature’s contribution to 

downstream water properly falls below the level of significant nexus. (p. 4)

Agency Response: See summary response 8.3 above on Difficulties in determining 

OHWM, length of break, and contribution of flow. 

Metropolitan Water District of Southern California (Doc. #14637)

8.371 c. The Agencies should clarify that natural or man-made breaks are not subject to 

CWA jurisdiction

In column one on page 22203 of the Federal Register notice, the proposed rule states that 

"natural or manmade breaks would still not sever jurisdiction if a tributary segment with 

a bed and bank and OHWM could be identified upstream of the break." Metropolitan 

requests that the Agencies clarify that natural or man-made breaks in tributaries are not 

also subject to jurisdiction under the CWA. It is not uncommon in small ephemeral 

drainages in the arid west to find such natural breaks, often extending many hundreds or 

even thousands of feet between areas that exhibit indicators for an OHWM. The 

discussion on pages 22202 and 22203 of the Federal Register notice does not explicitly 

identify these breaks as either subject to CWA jurisdiction or not. The Agencies should 

expressly state in the rule for the purpose of clarity that these breaks are not 

jurisdictional. (p. 9)

Agency Response: See summary response 8.3 above on General Comments 

Opposing and Supporting Approach to Break in OHWM. 

ERO Resources Corporation (Doc. #14914)

8.372 Many ephemeral and intermittent drainages in the arid West have a discontinuous bed 

and banks and/or OHWMs (discontinuous features). These discontinuous features are the 

result of infrequent flow events and are an indicator that such drainages may not have 

sufficient or consistent flow to connect to a WUS or physically, chemically, or 

biologically affect the integrity of a WUS. The Corps recognizes this common situation 

in Section IILB of the Approved JD Form discussed above that states: "[W]here there is a 

break in the OHWM that is unrelated to the waterbody's flow regime" (i.e., the Corps 

considers how flow regime relates to jurisdictional features in determining isolation). In 

many situations under current guidance and policy, the discontinuous nature of these 

features is substantial enough to "isolate" and render the drainages nonjurisdictional 

above these substantial breaks in jurisdictional features. Under the proposed rule, a water 

that otherwise qualifies as a tributary does not lose its status as a tributary if, for any

length, there are one or more man-made breaks, or one or more natural breaks so long as 

a bed and bank and OHWM can be identified upstream of the break. As proposed, the 
Clean Water Rule Response to Comments – Topic 8: Tributaries

500

rule would not consider any break in jurisdictional features, no matter how extensive, as 

justification to consider reaches above the break in features to be nonjurisdictional. This 

approach fails to consider the length of the break in relationship to flows that form the 

features to the overall drainage or the characteristics of the drainage.

For example, consider a 20-mile-Iong ephemeral drainage with an OHWM and bed and 

banks for its lower 5 miles with a 10-mile break in jurisdictional features, with the 

remaining upper 5 miles of drainage with intermittent indicators of an OHWM and a bed 

and banks. This drainage most certainly has a different probability of connection and 

physically, chemically, or biologically affecting the integrity of a WUS than the same 

length of an ephemeral drainage with a 1/8-mile break in jurisdictional features. As 

proposed, the rule has no approach for making such' distinctions in determining the 

jurisdictional status of ephemeral and intermittent drainages. Unfortunately, such 

examples are not the exception. Ephemeral and intermittent drainages with substantial 

breaks in jurisdictional features occur with enough frequency over the landscape of the 

arid West to render the proposed rule's approach arbitrary.

Substantial breaks in jurisdiction (discontinuous features) can also be indicative of an 

ephemeral or intermittent drainage with subsurface flow that occurs within the alluvium 

of the channel. The alluvial flow may be lost before reaching a WUS due to evaporation, 

consumptive use by riparian and wetland vegetation, diversions by shallow wells, and 

possibly infiltration to a suballuvial (deep ground water) aquifer. The discontinuous 

features may also be associated with channels with gradients that flatten and/or broaden. 

(p. 8-9)

Agency Response: See summary response 8.3 above on Difficulties in determining 

OHWM, length of break, and contribution of flow and TSD section 7.

Pennsylvania Independent Oil and Gas Association (Doc. #15167) 

8.373 If a "break" occurs in the tributary, is the area of the "break" considered to be 

jurisdictional? Asserting that a tributary still exists when water flows underground, 

through boulders or otherwise without a bed, bank and OHWM only confuses and 

complicates the "bright line" categories of jurisdictional waters reportedly sought by the 

agencies to simplify the jurisdictional determination process. (p. 17)

Agency Response: See summary response 8.3 above on General Comments 

Opposing and Supporting Approach to Break in OHWM.

Defenders of Wildlife and Patagonia Area Resource Alliance (Doc. #16394)

8.374 Defenders also supports the fact that under the proposed definition in (u)(5), a water that 

otherwise qualifies as a tributary “does not lose its status as a tributary if, for any length, 

there are one or more man-made breaks... or one or more natural breaks” including a 

“stream that flows underground.” One common trait of western streams is that they may 

flow above ground in some areas and below ground in others, dependent upon stream 

flow and substrate. It is common for western streams to flow above ground above 

impermeable rock and then sink below ground when traversing permeable limestone or 

alluvial depositions. A stream may travel below ground for a distance and then be forced 

to the surface by underlying igneous rock. Such underground connections that ultimately 
Clean Water Rule Response to Comments – Topic 8: Tributaries

501

link to waters of the U.S. should be covered under the definition of waters of the U.S. For 

example, Sonoita Creek is ephemeral where it flows through the town of Patagonia, but it 

surfaces on the west side of town at The Nature Conservancy’s Patagonia-Sonoita Creek 

Preserve. Contamination of the creek above the underground flow should be considered 

contamination of a waters of the U.S. because the water surfaces and ultimately links 

with Lake Patagonia and other waters of the U.S. (p. 6)

Agency Response: See summary response 8.3 above on General Comments 

Opposing and Supporting Approach to Break in OHWM.

Western Resource Advocates (Doc. #16460)

8.375 Tributaries above natural and human-caused breaks

The rule defines the word “tributary” for the first time and explicitly includes within this 

definition tributaries whose ordinary surface journey is broken either by a culvert or other 

constructed feature that channels its water under a road or building, or by a natural break 

in the surface water, e.g., a rock fall that forces the water under its surface.540 WRA 

supports this aspect of the rule. The key inquiry is whether the natural or constructed 

feature breaks the hydrologic connection between the tributary segments up and down 

stream. So long as the hydrologic connection is intact, the possibility of pollutants 

flowing downstream remains, as does the potential benefits of having the tributary’s 

dilution flow reach a larger waterway. Local entities responsible for constructing these 

sorts of conduits themselves seem to consider the watershed intact notwithstanding the 

conduit. For example, Two Mile Creek in Boulder County, Colorado is described as:

With its headwaters up what is now the Pine Brook Hills subdivision, Two Mile 

Creek-- like many small drainages-- is perennial, generally dry through most of its 

length from July to March. Between Broadway and Edgewood Twomile Creek is 

hidden from view in underground culverts, but where it emerges, just above the 

confluence with Goose Creek-- west of Folsom and south of Edgewood-- wild 

watercress is found.541

While disconnected, it is none-the-less posted for protection in the community:

542 (p. 16-17)

 

540 79 Fed. Reg. at 22263.

541 Boulder Area Sustainability Information Network, Two Mile Creek Information (2005), available at 

http://bcn.boulder.co.us/basin/watershed/2mile.html.

542 Id.
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502

Agency Response: See summary response 8.3 above on General Comments 

Opposing and Supporting Approach to Break in OHWM.

Missouri Coalition for the Environment (Doc. #16372)

8.376 E. Waters That Flow Through Karst Features in Missouri Provide Important Benefits as 

Waters of the United States.

Missouri also contains a large number of karst features such as sinkholes, karst wetlands, 

and losing streams, particularly in the southeastern portion of the state.543 Although most 

of the surface water in these systems is diverted underground, pollution upstream can still 

impact the quality of downstream segments. The proposed Rule’s Overview of Scientific 

Literature on Aquatic Resource Connectivity and Downstream Effects recognizes the 

importance and interconnectivity of these waters,544 as does the Missouri Department of 

Conservation.545

Because waters in these systems tend to descend below ground and later reemerge via 

springs, lakes, or other features, “any contaminant which affects ground water quality is 

likely to affect surface water quality.”546 These karst features mitigate the effects of 

floods via surface runoff storage, affect drinking water quality by conveying surface 

waters to aquifers,547 and support a high level of aquatic biodiversity.548 The proposed 

Rule explains that tributaries are still jurisdictional even when they are broken up by 

underground flow,549 but the final rule should also clarify that waters, such as karst 

wetlands, that have intermittent connectivity through groundwater to downstream 

jurisdictional waters are also jurisdictional under the CWA.550 This categorical inclusion 

would help protect the important ecological and biological services these features 

provide. (p. 13-14)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. As described in the 

summary responses 8.1 and 8.1.2, the final rule clearly requires the presence of both 

bed and banks and another indicator of OHWM, if one is not present then the water 

does not qualify as a tributary. Wetlands, lakes, ponds, and other features lacking a 

 

543 See William R. Elliot, Zoogeography and Biodiversity of Missouri Caves and Karst, 69 Journal of Cave and 

Karst Studies 135, 136 (2007), available at https://caves.org/pub/journal/PDF/v69/cave-69-01-135.pdf.

544 79 Fed. Reg. at 22,235 (“The significant nexus between a tributary and a downstream water is not broken where 

the tributary flows underground for a portion of its length, such as in karst topography.”).

545 See, e.g., Water Quality and Use, MO. Dep’t of Conservation, http://mdc.mo.gov/your-property/greenercommunities/missouri-watershed-inventory-and-assessment/big-piney-river/water- (last visited Oct. 15, 2014).

546 Id.

547 Sam Woolford et al., Physical, Chemical, and Biological Impacts of Geographically Isolated Wetlands on Waters 

of the United States, River Basin Center at the University of Georgia, at 25-30 (Sept. 2014).

548 See Elliot, supra note 72, at 151.

549 79 Fed. Reg. at 22,235, 22,263 (explaining that a tributary “does not lose its status as a tributary” even if it

includes one or more natural breaks such as “a stream that flows underground”).

550 As the Mississippi River Collaborative’s comments on the proposed Rule advise, when functional 

interconnectivity—both chemical and biological— is taken into account, karst wetlands such as those present in 

Missouri should be categorically included in the final rule as waters of the United States. See also Ducks Unlimited, 

Comment Letter to EPA & Army Corps of Engineers, Docket ID No. EPA-HQ-OW-2011-0880 at 63 (Nov. 5, 

2014).
Clean Water Rule Response to Comments – Topic 8: Tributaries

503

bed and banks and/or OHWM are no longer defined as tributaries in the Final Rule, 

but may be considered jurisdictional “waters of the United States” as adjacent 

waters or similarly situated waters with a significant nexus to (a)(1) through (3) 

waters. See also the summary response 8.3 above on General Comments Opposing 

and Supporting Approach to Break in OHWM for discussion of breaks in OHWM. 

O'Neil LLP (Doc. #16559)

8.377 Any final Rule should clarify that areas that constitute "natural or man-made breaks in 

tributaries" are not subject to jurisdiction under the CWA. It is not uncommon in small 

ephemeral drainages in arid areas of the western United States to find such natural 

breaks, often times extending hundreds or thousands of feet between areas that exhibit 

indicators for an OHWM. For a feature to be classified within the definition of tributary, 

it ought to be required to have, at a minimum, a bed and banks and an ordinary high 

water mark (except where a wetland is the tributary in question), because these features 

generally are the physical indicators of flow. (p. 8)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. As described in the 

summary responses 8.1 and 8.1.2, the final rule clearly requires the presence of both 

bed and banks and another indicator of OHWM, if one is not present then the water 

does not qualify as a tributary. Wetlands, lakes, ponds, and other features lacking a 

bed and banks and/or OHWM are no longer defined as tributaries in the Final Rule, 

but may be considered jurisdictional “waters of the United States” as adjacent 

waters or similarly situated waters with a significant nexus to (a)(1) through (3) 

waters. See also the summary response 8.3 above on General Comments Opposing 

and Supporting Approach to Break in OHWM for discussion of breaks in OHWM.

8.4. TRIBUTARIES DISTINGUISHED FROM NON-JURISDICTIONAL GULLIES, RILLS, NONWETLAND SWALES

Agency Summary Response

Issue: Distinction between an ephemeral water and a non-jurisdictional gulley, rill or nonwetland swale

Several commenters were supportive of the proposed rule’s approach, and stated that certain 

erosional features, especially gullies, should be covered as jurisdictional. The Agencies 

determined, based on their scientific and technical expertise that waters meeting the definition of 

“tributary” in a single point of entry watershed are similarly situated and have a significant nexus 

because they significantly affect the chemical, physical, and biological integrity of traditional 

navigable waters, interstate waters, and the territorial seas. As such, it is appropriate to conclude 

covered tributaries as a category are “waters of the United States.” See Technical Support 

Document. The Agencies limited the tributaries that are “waters of the United States” to those 

that have both a bed and banks and another indicator of ordinary high water mark. That 

limitation served as a reasonable basis to consider covered tributaries similarly situated because 

those physical characteristics indicated sufficient flow that the covered tributaries are performing 

similar functions and located such that they are working together in the region to provide those 
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functions to the nearest traditional navigable water, interstate water, or the territorial seas. 

However, gullies and other erosional features typically do not have both a bed and banks and 

another indicator of ordinary high water mark because they do not have flow of sufficient 

volume, frequency, and duration to create the physical characteristics of bed and banks and an 

ordinary high water mark. Because the Agencies based their significant nexus determination for 

covered tributaries in part on the amount of flow indicated where a tributary had both a bed 

banks and another indicator of ordinary high water mark, the final rule continues to require both 

physical indicators. Thus, unless a gulley or other erosional feature has both a bed and banks 

and another indicator of ordinary high water mark, such gulley or erosional feature is not 

considered a covered tributary.

Many commenters requested that the Agencies explain in detail the definitional difference 

between an ephemeral water of the U.S. and a non-jurisdictional gulley, rill or non-wetland 

swale, and asked where this distinction is made in the proposed rule. Several commenters 

requested that the Agencies define various terms in the rule including gullies, rills, non-wetland 

swales, and uplands and expressed the need for training on differentiating between gullies and 

ephemeral streams. Still other commenters requested more clarity in the definition of tributary 

as the rule provides no meaningful distinction and is arbitrary.

A number of commenters stated that they were concerned about being able to distinguish the 

difference between regulated streams and exempt erosional features such as gullies and rills. 

Many commenters were confused why ephemeral streams are being treated differently than 

gullies, rills and non-wetland swales. Many commenters also stated that they felt that ephemeral 

streams and ditches with less than perennial flow should not be considered a jurisdictional 

tributary and should be categorically excluded. These commenters stated that no scientific 

literature or justification exists to treat ephemeral streams differently than gullies. Other 

commenters suggested that the rule contain a variance provision because not all headwaters are 

the same, especially, in the arid West, and some minimal contribution of flow when it rains does 

not equal a significant nexus sufficient to assert categorical jurisdiction.

The rule’s definition of “tributary” retains many elements from the proposed rule, but reflects 

public comments in several important ways. In particular, the rule focuses on the physical 

indicators of flow. The rule defines “tributary” by emphasizing physical characteristics created 

by water flow and requiring that the waterbody contributes flow, either directly or through 

another water, to a traditional navigable water, interstate water, or the territorial seas. The 

Agencies recognize that distinctions between ephemeral tributaries and erosional features can be 

confusing, and understand the commenters’ concerns that an ephemeral water that flows very 

rarely would be considered a jurisdictional tributary. The rule definition of “tributary” responds 

to these concerns by requiring that flow must be of sufficient volume, frequency, and duration to 

create the physical characteristics of bed and banks and an ordinary high water mark. If a water 

lacks sufficient flow to create such characteristics, it is not considered “tributary” under this rule. 

By relying on these physical characteristics of flow, the final rule will simplify the distinction 

between jurisdictional tributaries and non-jurisdictional features. The Agencies understand the 

commenters concern that a feature that flowed very infrequently could meet the proposed 

definition of “tributary,” and it is the agencies’ judgment that such a feature is not a tributary 

under the rule because it would not form the physical indicators required under the definitions of 
Clean Water Rule Response to Comments – Topic 8: Tributaries

505

“ordinary high water mark” and “tributary.” To further emphasize this point, the rule expressly 

indicates in paragraph (b) that ephemeral reaches that do not meet the definition of tributary are 

not “waters of the United States.” Because of the clarity provided by the final rule, and the 

simplified distinction it creates between jurisdictional tributaries and non-jurisdictional features 

which could include some headwaters, the final rule does not include a variance provision.

Under the rule, ephemeral streams that meet the definition of tributary are “waters of the United 

States,” because the agencies determined that such streams provide important functions for 

downstream waters, and in combination with other covered tributaries in a watershed 

significantly affect the chemical, physical, and biological integrity of traditional navigable 

waters, interstate waters, and the territorial seas. As noted by the SAB, and consistent with the 

scientific literature, tributaries as a group exert strong influence on the chemical, physical, and 

biological integrity of downstream waters, even though the degree of connectivity is a function 

of variation in the frequency, duration, magnitude, predictability, and consequences of chemical, 

physical, and biological processes. See, e.g., SAB 2014b. These significant effects on traditional 

navigable waters, interstate waters and the territorial seas occur even when the tributary is small, 

intermittent, or ephemeral. See also the summary responses in Section 9 “Scientific Evidence 

Supporting the Rule” of the Response to Comments.

In addition, the Science Report concludes that, “[a]lthough less abundant, the evidence for 

connectivity and downstream effects of ephemeral streams was strong and compelling, 

particularly in context with the large body of evidence supporting the physical connectivity and 

cumulative effects of channelized flows that form and maintain stream networks.” Science 

Report at 6-13. For example, ephemeral headwater streams shape river channels in traditional 

navigable or interstate waters by accumulating and gradually or episodically releasing stored 

materials such as sediment and large woody debris. These materials help structure traditional 

navigable and interstate river channels by slowing the flow of water through channels and 

providing substrate and habitat for aquatic organisms. 

Moreover, the agencies have historically considered ephemeral tributaries to be “waters of the 

United States.” For example, for many years EPA has reviewed and approved state water quality 

standards for ephemeral waters under CWA section 303(c), several Corps’ Nationwide Permits 

under CWA section 404 address discharges of dredged or fill material into ephemeral waters, 

and the agencies’ definition of “waters of the United States” prior to this rule included all 

tributaries without reference to flow regime. Thus, the Agencies are not regulating every 

ephemeral stream; only those that possess both a bed and banks and an additional indicator of 

ordinary high water mark because they are indicators of sufficient flow to have a significant 

effect on the chemical, physical, and biological integrity of traditional navigable waters, 

interstate waters, and the territorial seas. The Agencies believe that requiring the physical 

indicators of bed and banks and ordinary high water mark will help clarify the distinction 

between covered tributaries and erosional features, and simplify implementation of the final rule.

Several commenters stated that the upper limit of a tributary should be clearly defined, and that 

the rule should state that a break in OHWM should be deemed the upper limit of jurisdiction. 

Additional commenters stated that the rule was not clear if surface connections without an 

OHWM could connect distant WOUS, and that this lack of clarity in the rule will cause an 
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506

increase in review time in the office and in the field for the regulators and the regulated public 

who would need to review distant locations beyond the limits of the project. Another commenter 

felt that clarification was needed about allowing for excluded features, such as groundwater, 

gullies and rills, to serve as connections that can render a feature jurisdictional as an “adjacent 

water” or “other water.” 

Gullies, rills and non-wetland swales are not WOUS, and are excluded water features in 

paragraph (b) of the final rule, because they are erosional features that lack sufficient volume, 

frequency, and duration of flow to have the physical characteristics of bed and banks and another 

indicator of ordinary high water mark. Thus, they do not have a significant nexus. Streams with 

a break in ordinary high water mark can be “waters of the US” under current practice, and the 

final rule does not change this practice. The upper limit of the tributary is the point where a bed 

and banks and another indicator of ordinary high water mark cease to be identifiable. The 

ordinary high water mark establishes the lateral limits of a water, and its absence generally 

determines when a tributary’s channel or bed and banks has ended, representing the upper limit 

of the tributary. However, a natural or constructed break in bed and banks or other indicator of 

ordinary high water mark does not constitute the upper limit of a tributary where bed and banks 

and another indicator of ordinary high water mark can be found farther upstream. By looking to 

the presence of a bed and banks and an ordinary high water mark upstream, the rule ensures that 

a mere break in the ordinary high water mark does not render tributaries with a significant nexus 

to downstream waters non-jurisdictional. 

With regard to surface connections or excluded features, such as groundwater, gullies and rills, 

features which are not “waters of the US” themselves, can in certain instances, provide a 

connection from a “water of the US” to a “water of the US” (see Compendium 3 on Adjacency 

section). Confined surface connections, such as culverts, can be used to demonstrate a 

connection between stream segments even if there is a break in ordinary high water mark as long

as the ordinary high water mark and bed and banks are found upstream of the break. 

The Agencies believe that requiring the physical indicators of bed and banks and ordinary high 

water mark will help clarify the distinction between covered tributaries and erosional features, 

and simplify implementation of the final rule. The clarification and simplification provided by 

the final rule will reduce – not increase – review time in the office and in the field for regulators 

and the regulated public.

Issue: Need for additional factors and specific guidance and methodology on determining bed 

and banks and OHWM, especially in the arid West.

A number of commenters requested that the rule contain some type of objective criteria about the 

significance of a break in the OHWM to recognize that a 1/8 mile break in OHWM versus a 10 

mile break has a very different probability of connection and physically, chemically, or 

biologically affecting the integrity of water of the U.S. This concern was raised especially by 

commenters from the arid West who described water features that dissipate, as well as water 

features that have what could be termed an OHWM after flow events but not really be an 

OHWM. Commenters from the arid West also stated that the proposed rule’s approach is 

negating the effect of substantial breaks in jurisdiction.
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The final rule definition makes clear that a water is considered tributary if it contributes flow, 

either directly or through another water, to a traditional navigable water, interstate water, or the 

territorial seas, and that the water has the physical indicators of a bed and banks and an ordinary 

high water mark. These physical indicators demonstrate there is volume, frequency and duration 

of flow sufficient to create a bed and banks and an ordinary high water mark, and thus to qualify 

as a tributary. If a water does not contribute flow, either directly or through another water, to a 

traditional navigable water, interstate water, or the territorial seas, such water does not qualify as 

a tributary. Site specific conditions will continue to determine the distance up valley that needs 

to be evaluated to see if the break in bed and banks and OHWM is temporary or the start of the 

stream system. These conditions include the size of the stream (larger streams require looking 

further up valley) and the nature of the break (look to see the up valley end of manmade breaks, 

streams buried by colluvium and valley bottom alluvial fans). Conversely, where the bed and 

banks and OHWM simply fade away or abruptly end at a headcut and the substrate, land use and 

valley characteristics do not change above and below the break, minimal up valley evaluation is 

necessary. The time it takes for water to make the connection between the waters above and 

below a break in OHWM will continue to be considered when evaluating breaks in OHWM and 

is largely dependent on the nature of the break. While there has never been a time limit on 

connections, times much longer than would occur if the break was not present point to the 

presence of distinct waterbodies instead of a single waterbody. For a complete discussion of 

how to address breaks in OHWM see summary response 8.3 above. 

A number of commenters suggested that identifying bed and banks can be difficult, especially in 

the arid West. A number commenters stated that all three indicators of OHWM be required to be 

present in order to determine the existence of an OHWM, and sought specific criteria for the arid 

West. The commenters pointed out recent activity by the Corps on OHWM guidance, and stated 

that such important guidance should have gone through notice and comment rulemaking. Other 

commenters sought a methodology for identifying OHWM which should be included in the rule.

To increase clarity and address the comments requesting a definition of bed and banks, the 

preamble in section IV(F) includes an explanation of bed and banks adapted largely from 

longstanding agencies’ practice as well as public comments on the proposed rule. In response to 

commenters’ suggestions that the rule add a definition of “ordinary high water mark,” the final 

rule adds the Corps’ existing regulatory OHWM definition to EPA’s regulations. Under that 

existing Corps regulation, indicators of OHWM include characteristics such as shelving, scour, 

changes in soil characteristics, and destruction of terrestrial vegetation, among others. The 

comments related to Corps guidance needing to go through notice and comment rulemaking are 

beyond the scope of this rulemaking and are not addressed further. The preamble notes that 

several Corps technical manuals are available to help identify OHWM. For areas such as the 

arid west, the Arid West Field Guide for OHWM manual has been developed for OHWM 

identification and has been used by the agencies for a number of years. Supporting research and 

technical reports have also been developed by the Corps. The Agencies are considering the need 

to develop further guidance or methodologies for identifying ordinary high water mark.

A number of commenters suggested that rule should include the magnitude, duration, and 

frequency of flow as consideration for distinguishing between exempt erosional features and 

covered ephemeral tributaries. Other commenters suggested factors the Agencies should 
Clean Water Rule Response to Comments – Topic 8: Tributaries

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consider in differentiating between excluded erosional features such as gullies and rills, and 

ephemeral tributaries, including past land use information, historic aerials, indicators of erosional 

conditions only, alternating sediment depositional segments, the presence of vegetation growing 

within the feature, the presence of plant litter from previous years, and differentiation within the 

substrate. 

OHWMs are created and maintained because of the presence of flowing water of sufficient 

volume, frequency, and duration to create those physical characteristics. Erosional features do 

not have the same flow characteristics and therefore do not have the same indicators as an 

ephemeral tributary. Some gullies may have been recently formed and over time may develop 

characteristics of a tributary through sufficient volume, frequency, and duration of flow. Thus, 

the Agencies believe that the rule, by requiring bed and banks and OHWM, does include 

consideration of the magnitude, duration, and frequency of flow as consideration for 

distinguishing between exempt erosional features and covered ephemeral tributaries. The rule 

definition of “tributary” requires that flow must be of sufficient volume, frequency, and duration 

to create the physical characteristics of bed and banks and an ordinary high water mark. If a 

water lacks sufficient flow to create such characteristics, it is not considered “tributary” under 

this rule. The Agencies understand the commenters concern about distinguishing between 

exempt erosional features and ephemeral waters that could meet the proposed definition of 

“tributary,” but it is the agencies’ judgment that such an erosional feature is not a tributary under 

the rule because it would not form the physical indicators required under the definitions of 

“ordinary high water mark” and “tributary.” To further emphasize this point, the rule expressly 

indicates in paragraph (b) that ephemeral reaches that do not meet the definition of tributary are 

not “waters of the United States.”

With regard to the commenters’ suggested factors that the Agencies should consider in 

differentiating between excluded erosional features and ephemeral tributaries, the Agencies are 

including the Corps’ existing definition of ordinary high water mark in EPA’s regulations to 

provide additional clarity and for ease of use for the public. Existing Corps regulations define 

ordinary high water mark as the line on the shore established by the fluctuations of water and 

indicated by physical characteristics such as a clear, natural line impressed on the banks, 

shelving, changes in the character of soil, destruction of terrestrial vegetation, the presence of 

litter and debris, or other appropriate means that consider the characteristics of the surrounding 

areas. 33 CFR 328.3(e). That definition is not changed by the rule. Because ordinary high water 

mark indicators include characteristics such as shelving, scour, changes in soil characteristics, 

and destruction of terrestrial vegetation, among others, as well as remote sensing sources of 

information or mapping, the Agencies conclude that many – if not most - of the factors identified 

in the comments are considered in differentiating between excluded erosional features and 

ephemeral tributaries.

Issue: Lack of clarity problematic for certain sectors including farming, ranching, and mining.

A number of commenters were concerned that inclusion of ephemeral waters that meet the 

definition of tributary as waters of the U.S. is an expansion of jurisdiction and would cause 

farmers and ranchers difficulty in determining what they could do on their land. Other 

commenters were also concerned about irrigation practices and ditches creating WOUS. 
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509

The Agencies respectfully disagree that coverage of ephemeral waters that meet the definition of 

tributary is an expansion of jurisdiction that would cause farmers and ranchers difficulty in 

determining what they could do on their land. The Agencies have long regulated all tributaries, 

including ephemeral tributaries, under the CWA (see Section I of the Technical Support 

Document). The Agencies believe that requiring the physical indicators of bed and banks and 

ordinary high water mark will help clarify that only ephemeral waters with sufficient flow will 

meet the definition tributary. This approach will simplify implementation of the final rule. The 

clarification and simplification provided by the final rule will make it easier – not harder – for 

farmers and ranchers to determine what they can do on their land. In addition, all of the statutory 

exemptions in the CWA, including those exempting normal farming, silviculture and ranching 

practices from the need to obtain CWA section 404 authorization, remain in effect and 

unchanged by the final rule.

With regard to commenters’ concern about irrigation practices and ditches creating WOUS, 

certain ditch maintenance activities, including those on existing irrigation and drainage ditches, 

are exempt from CWA section 404 permitting requirements under section 404(f) of the CWA. 

Section (b)(4) of the final rule also excludes artificially irrigated areas that would revert to dry 

land should application of water to that area cease. In addition, section (b)(3) of the final rule 

contains an exclusion for certain ditches even if they otherwise meet the definition of tributary. 

Ditches with ephemeral or intermittent flow not constructed or excavated in a tributary are not 

waters of the US. Ditches that do not flow, either directly or through another water, into a 

traditional navigable water, interstate water, or the territorial seas are not waters of the US. 

Thus, the Agencies believe that the exclusions contained in the final rule, as well as the existing 

statutory exemptions under CWA section 404(f) address the concerns raised by the commenters. 

Several commenters stated that mining activities and mining reclamation activities often create 

erosional features that should not be considered tributaries. Because these activities create large 

areas of disturbed soil, under certain slope and stability considerations such features could 

arguably form a bed and bank and OHWM. Also, many such activities are already regulated 

under CWA section 402 (individual or general) permits. These commenters indicated that the

approach in the proposed rule will create uncertainty, lead to coverage of more waters than 

Congress intended, and be arbitrary. 

The Agencies believe that requiring the physical indicators of bed and banks and ordinary high 

water mark is not arbitrary, will help clarify the distinction between covered tributaries and 

erosional features, and simplify implementation of the final rule for those involved in mining and 

mining reclamation activities. The Agencies respectfully disagree that coverage of ephemeral 

waters that meet the definition of tributary will create uncertainty or lead to coverage of more 

waters than Congress intended. OHWMs are created and maintained because of the presence of 

flowing water of sufficient volume, frequency, and duration to create the physical characteristics. 

Erosional features caused by mining activities and mining reclamation activities do not have the

same flow characteristics and therefore do not have the same indicators as an ephemeral 

tributary. The fact that mining activities and mining reclamation activities may already be 

regulated under CWA section 402 (individual or general) permits has no bearing on whether a 

feature has the physical indicators of bed and banks and ordinary high water mark such that it 

would be considered a covered tributary. Additionally, Section I of the Technical Support 
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510

Document provides the legal framework under which a ditch could be considered both a point 

source regulated under CWA section 402 and a water of the United States. 

The final rule does not establish any regulatory requirements. Instead, it is a definitional rule that 

clarifies the scope of “waters of the United States” consistent with the Clean Water Act, Supreme 

Court precedent, and science. Programs established by CWA sections 402, 404 and 311 all rely 

on the definition of “waters of the United States.” 

Specific Comments

U.S. House of Representatives Committee on Space, Science and Technology (Doc. #16386)

8.378 The word "ephemeral" appears over 75 times in the preamble to the proposed rule, but it 

is not defined. EPA's Connectivity Report defines "Ephemeral Stream" as "A stream or 

river that flows briefly in direct response to precipitation; these channels are above the 

water table at all times." According the preamble to your proposed rule: "Rills are 

formed by overland water flows eroding the soil surface during rain storms."

a. Please explain in detail definitional difference between an ephemeral water of the U.S. 

and a non-jurisdictional rill.

b. Where is this distinction made in the proposed rule? (p. 15-16).

Agency Response: See the summary response for Section 8.4. Section VII of the 

Technical Support Document also discusses the differences between rills and other 

non-jurisdictional erosional features and ephemeral tributaries that are waters of 

the United States.

North Carolina Department of Agriculture and Consumer Services (Doc. #14747)

8.379 The proposed rule exempts gullies and swales from jurisdiction; however, neither term is 

defined in the proposed rule. Will field staff be able to determine where a gully or swale 

ends and an ephemeral stream or ditch begins? More importantly, will landowners be 

able to determine if these features exist on their property? The fact that EPA and USACE 

are requesting comment on the difference between these features only serves to 

demonstrate the difficulty that landowners will face if ephemeral streams are 

jurisdictional. (p. 3) 

Agency Response: See the summary response for Section 8.4, particularly the subsection titled, “Distinction between an ephemeral water and a non-jurisdictional 

gulley, rill or non-wetland swale.” The definition of “tributary” in the final rule 

requires that flow must be of sufficient volume, frequency, and duration to create 

the physical characteristics of bed and banks and an ordinary high water mark. If a 

water lacks sufficient flow to create such characteristics, it is not considered 

“tributary” under this rule. It is the agencies’ judgment that erosional features are 

not tributaries under the rule, because they would not form the physical indicators 

required under the definitions of “ordinary high water mark” and “tributary.”
Clean Water Rule Response to Comments – Topic 8: Tributaries

511

State of Oregon (Doc. #15218)

8.380 ... there is continued uncertainty about the application of the proposed rule to specific 

geographic and hydrologic conditions. For example, while we appreciate the proposed 

express exclusion of "[g]ullies and rills and non-wetland swales," at the same time the 

proposed rules expressly includes all tributaries of waters susceptible of use in interstate 

commerce. It remains unclear to Oregon how this proposed language may apply to 

ephemeral streams that some may consider "gullies" and others may consider tributaries. 

(p. 2)

Agency Response: See the summary response for Section 8.4, particularly the subsection titled, “Distinction between an ephemeral water and a non-jurisdictional 

gulley, rill or non-wetland swale.” The definition of “tributary” in the final rule 

requires that flow must be of sufficient volume, frequency, and duration to create 

the physical characteristics of bed and banks and an ordinary high water mark. If a 

water lacks sufficient flow to create such characteristics, it is not considered 

“tributary” under this rule. It is the agencies’ judgment that erosional features are 

not tributaries under the rule, because they would not form the physical indicators 

required under the definitions of “ordinary high water mark” and “tributary.”

Furthermore, erosional features, such as gullies, rills and non-wetland swales, are 

expressly excluded in paragraph (b) of the final rule. Paragraph (b) also clearly 

indicates that all such excluded features are not waters of the United States even 

where they otherwise meet the terms of paragraph (a), which defines “waters of the 

United States.”

Ohio Department of Natural Resources et al. (Doc. #15421)

8.381 2. The agencies request comment on how they could provide greater clarity on how to 

distinguish between erosional features such as gullies, which are excluded from 

jurisdiction, and ephemeral tributaries, which are categorically jurisdictional.

MRM: It is of concern that reclamation of unreclaimed areas previously mined for coal 

and is eligible for the remining incentives offered by the Rahall Amendment to the Clean 

Water Act [Clean Water Act Section 301(p)], would be negatively impacted by the 

provisions of the proposal. Nothing in the proposal should be interpreted so as to increase 

impediments to remining and reclamation of unreclaimed coal strip mining pits, 

highwalls, and sediment-laden and acid mine drainage impacted streams, as intended by 

the Rahall Amendment. There have been past incidents where erosional features from 

pre-law pit impoundments and from mine spoil has been categorized as jurisdictional 

even though the features clearly do not meet the definition of a "tributary". If so, this 

would be a disincentive to mine operators to remove the remaining coal from these areas 

and complete restoration if there are costly mitigation requirements. (p. 11)

Agency Response: The agencies disagree that these types of features or activities 

should be categorically excluded from consideration as “waters of the United 

States.” The agencies support the goals of remining activities but feel it is more 

appropriate to encourage these activities through streamlined permitting options, 

such as Nationwide Permits. The final rule provides greater clarity on distinguishing

between covered tributaries and erosional features. See exclusions compendium 
Clean Water Rule Response to Comments – Topic 8: Tributaries

512

(topic 7). The final rule is a definitional rule, and the Rahall Amendment and 

compensatory mitigation requirements are outside the scope of the rule.

8.382 3. The agencies request comment on how they could provide greater clarity on how to 

distinguish swales, which are exclude d from jurisdiction, and ephemeral tributaries, 

which are categorically jurisdictional.

MRM: There has been historical inconsistency among federal agency (ACOE) regions 

and staff regarding jurisdictional swales and/or ephemeral streams or "tributary". It is 

recommended that the agency clearly provide a definition and distinction between 

"swale" from a jurisdictional ephemeral tributary. (p. 11)

Agency Response: See the summary response for Section 8.4, particularly the subsection titled, “Distinction between an ephemeral water and a non-jurisdictional 

gulley, rill or non-wetland swale.”

City of Chesapeake, Virginia (Doc. #9615)

8.383 The Rule states that a tributary is a WOUS, and a tributary may be ephemeral, 

intermittent or perennial. This statement is in direct conflict with the exemption for

ditches that have less than perennial flow. Ephemeral and intermittent ditches are not 

tributaries and should not be subject to regulatory oversight under the CWA. The Corps' 

Nationwide Permit program defines an ephemeral stream having flowing water only 

during, and for a short duration after, precipitation events in a typical year; in addition, 

ephemeral stream beds are located above the water table year-round and groundwater is 

not a source of water for the stream. Since runoff from rainfall is the primary source of 

water for ephemeral stream flow, why are ephemeral streams being regulated any 

differently than gullies, rills and non-wetlandnonwetland swales? Ephemeral streams as 

well as ditches with less than perennial flow should be explicitly exempt to regulatory 

oversight under the CWA. (p. 3)

Agency Response: The final rule provides exclusions for most ditches that are not 

relocated tributaries or excavated in a tributary. The agencies disagree that 

ephemeral streams should be categorically excluded from consideration as waters of 

the United States. See summary response for “Relevance of Flow Regime” in 

section 8.1.1 of this RTC, particularly subsections on jurisdiction over intermittent 

and ephemeral waters and the legality of asserting jurisdiction over ephemeral 

waters. Section IV(F) of the preamble to the final rule and section VII of the 

Technical Support Document discuss tributaries, including man-made or manaltered tributaries. The final rule is consistent with the agencies’ longstanding 

interpretation of the CWA that a tributary can be a natural, man-altered, or manmade water. See also the summary response for “Relevance of Flow Regime” in 

section 8.1.1 above, particularly the subsection on “Regulation of Man-Altered 

Streams” and the summary response for section 8.2 above, “Ditches as Tributary.” 

As defined in the final rule, “tributaries” thus include waters such as rivers, 

streams, canals, and ditches not excluded under paragraph (b). 
Clean Water Rule Response to Comments – Topic 8: Tributaries

513

County of Henry, Virginia (Doc. #10949)

8.384 The Rule states that a tributary is a WOUS, and a tributary may be ephemeral, 

intermittent or perennial. Ephemeral and intermittent ditches are not tributaries and 

should not be subject to regulatory oversight under the CWA. The Corps' Nationwide 

Permit program defines an "ephemeral stream" as having "flowing water only during, and 

for a short duration after, precipitation events in a typical year; in addition, ephemeral 

stream beds are located above the water table year-round and groundwater is not a source 

of water for the stream." Since runoff from rainfall is the primary source of water for 

ephemeral stream flow, why are ephemeral streams being regulated any differently than 

gullies, rills and non-wetland swales? Ephemeral streams as well as ditches with less than 

perennial flow should be explicitly exempt to regulatory oversight under the CWA. (p. 2)

Agency Response: The final rule provides exclusions for most ditches that are not 

relocated tributaries or excavated in a tributary. The agencies disagree that 

ephemeral streams should be categorically excluded from consideration as waters of 

the United States. See summary response for “Relevance of Flow Regime” in 

section 8.1.1 of this RTC, particularly subsections on jurisdiction over intermittent 

and ephemeral waters and the legality of asserting jurisdiction over ephemeral 

waters. Section IV(F) of the preamble to the final rule and section VII of the 

Technical Support Document discuss tributaries, including man-made or manaltered tributaries. The final rule is consistent with the agencies’ longstanding 

interpretation of the CWA that a tributary can be a natural, man-altered, or manmade water. See also the summary response for “Relevance of Flow Regime” in 

section 8.1.1 above, particularly the subsection on “Regulation of Man-Altered 

Streams” and the summary response for section 8.2 above, “Ditches as Tributary.” 

As defined in the final rule, “tributaries” thus include waters such as rivers, 

streams, canals, and ditches not excluded under paragraph (b). 

Board of Supervisors, Maricopa County, Arizona (Doc. #14132.1)

8.385 ...the definition of "other waters" includes several words that have conflicting definitions 

used by the U.S. Department of Agriculture's National Resources Conservation Service 

or other water entities (i.e. "rill" and "gully" are both excluded from tributary definition 

in this proposed rule but in other agency definitions they are "intermittent streams"). 

These sections must be re-worked if the agencies really seek to clarify the reach of WUS. 

(p. 5)

Agency Response: The definition of “tributary” in the final rule requires that flow 

must be of sufficient volume, frequency, and duration to create the physical 

characteristics of bed and banks and an ordinary high water mark. If a water lacks 

sufficient flow to create such characteristics, it is not considered “tributary” under 

this rule. The agencies are aware that terms such as “gully” and “rill” may have 

different meanings throughout the country. Therefore, by grounding the definition 

of “tributary” in the final rule to the above referenced specific physical features, the

agencies believe that confusion regarding whether a feature is a “tributary” or a 

non-jurisdictional “erosional feature” will be minimal. Regardless of the name they 

are given locally, waters that meet the definition of tributary are not excluded 

erosional features.
Clean Water Rule Response to Comments – Topic 8: Tributaries

514

Washington County Commission, Utah (Doc. #14991)

8.386 In the proposed rule, the Agencies specifically request comments regarding 

recommendations which will provide greater clarity to the proposed definition of 

jurisdictional tributaries as compared to non-jurisdictional gullies. As stated above, the 

county has expertise in maintaining roads in an area with frequent and localized flash 

flooding. Consequently, the county respectfully provides additional information to the 

Agencies with the intent of showing the need to not include dry washes or arroyos as 

jurisdictional by rule.

The proposed rule offers little, if any, guidance to differentiate ephemeral tributaries from 

gullies, merely stating that gullies are erosional features and defining tributaries as having 

a bed, banks, and high water mark. Additionally, the proposed rule in inconsistent in that 

it states it seeks to follow current practices , but also implies that ephemeral streams in 

the arid west ("dry washes" or "arroyos") will be considered tributaries and jurisdictional 

by rule. However, it is not the current practice of the agencies to regulate dry washes in 

the county. (p. 3)

Agency Response: See the summary response for Section 8.4.

South Big Horn County Conservation District, Wyoming (Doc. #17264)

8.387 The proposed rule describes a tributary as having a bed and banks and normal high water 

mark. The rule then goes on to exempt rills and gullies. The rule does not define when a 

rill or gully becomes a regulated tributary, however rills and gullies typically have these 

same physical features. (p. 2)

Agency Response: See the summary response for Section 8.4, particularly the subsection titled, “Distinction between an ephemeral water and a non-jurisdictional 

gulley, rill or non-wetland swale.”

Virginia Department of Transportation (Doc. #12756)

8.388 We are concerned that certain swales, rills, and ephemeral tributaries could be considered 

jurisdictional despite the attempt to exempt some of these waters. Under the second 

column of p.22202, the preamble states that a natural or manmade break in the Ordinary 

High Water Mark does not constitute the upper limit of a tributary. The rule should 

clearly state when such a break should not be deemed the upper limit of jurisdiction. It is 

not clear if surface connections without an Ordinary High Water Mark could connect 

distant WOUS. This lack of clarity in the rule will cause an increase in review time in the 

office and in the field for the regulators and the regulated public (potentially at distant 

locations beyond the project limits). (p. 5-6)

Agency Response: Erosional features, including gullies, rills and swales are 

excluded from consideration as waters of the United States under paragraph (b) of 

the final rule. In contrast, waters meeting the definition of “tributary,” including 

ephemeral tributaries, and not explicitly excluded in paragraph (b) are waters of the 

United States. The definition of “tributary” has been clarified in the final rule, and 

no longer includes ponds, lakes, and wetlands as tributaries. See the summary 

response for Section 8.3.2 above, particularly the subsection titled, “Relevance of 

Breaks in OHWM.” The agencies are uncertain how to interpret the commenter’s 
Clean Water Rule Response to Comments – Topic 8: Tributaries

515

scenario of “surface connections without an Ordinary High Water Mark could 

connect distant WOUS.”

Association of Clean Water Administrators (Doc. #13069)

8.389 A final rule could provide increased clarity for identifying tributaries and adjacent waters 

if clearer definitions are developed... Terms like rills, gullies and uplands are also not 

defined...(p. 3)

Agency Response: The final rule includes revised and clarified definitions for 

“tributary” and “adjacent.” The term “uplands” has been removed from the 

description of the exclusions for ditches in paragraph (b) of the final rule. The 

definition of “tributary” in the final rule requires that flow must be of sufficient 

volume, frequency, and duration to create the physical characteristics of bed and 

banks and an ordinary high water mark. If a water lacks sufficient flow to create 

such characteristics, it is not considered “tributary” under this rule. The agencies 

are aware that terms such as “gully” and “rill” may have different meanings 

throughout the country. Therefore, by grounding the definition of “tributary” in 

the final rule to the above referenced specific physical features, the agencies believe 

that confusion regarding whether a feature is a “tributary” or a non-jurisdictional 

“erosional feature” will be minimal. Regardless of the name they are given locally, 

waters that meet the definition of tributary are not excluded erosional features.

Western Coalition of Arid States (Doc. #14407)

8.390 The agencies propose to exclude gullies, rills, and non-wetland swales, but do not 

propose definitions of those terms. The preamble states that the agencies specifically seek 

comment on how to distinguish between erosional features, such as gullies, which are 

excluded from jurisdiction, and ephemeral tributaries, which are categorically 

jurisdictional.

The agencies should exclude erosional features like rills and gullies from jurisdiction 

when their formation can be clearly associated with mining, construction or other 

manmade projects that disturb large areas. These types of activities create expansive 

areas of disturbed soils and, under certain slope and stability characteristics, are prone to 

producing erosion that is actively controlled under the §402 Construction General and 

Industrial General Permits or MS4 permit programs. There is no need to further clarify 

the definition or description of a non-wetland swale. The agencies are already defining 

ephemeral tributaries. If a depressed feature does not have a bed, bank and OHWM per 

agency guidance, it is not a jurisdictional water. Non-wetland swales will not be included 

in this definition. (p. 16)

Agency Response: Erosional features like rills and gullies are excluded in 

paragraph (b) of the final rule regardless of their reason for forming.

Western Urban Water Coalition (Doc. #15178.1)

8.391 ...As discussed below, determinations of nonjurisdiction for ephemeral and intermittent 

drainages based on isolation occur in the arid West (SWCA Environmental Consultants 

2014a and Corps Approved JD Form). These nonjurisdictional determinations include:
Clean Water Rule Response to Comments – Topic 8: Tributaries

516

 Ephemeral and intermittent drainages with substantial breaks in jurisdictional 

features where the break in jurisdictional features makes it unlikely that flows 

reach a WUS.

 Ephemeral and intermittent drainages with no breaks in jurisdictional features that 

contain no surface flow during most years due to dry conditions and/or human 

surface and shallow ground water diversions that reduce streamflow to zero.

 Erosional gullies that do not have jurisdictional features except where they 

transport irrigation runoff.

 Ephemeral and intermittent drainages where the channel ends in a fan or sheet 

flows over the landscape and makes it unlikely that flows reach a WUS.

 Ephemeral and intermittent drainages where the channel loses definition due to 

agricultural or other activities that make it unlikely that flows reach a WUS.

 Ephemeral and intermittent drainages where the channel loses surface or 

subsurface flow that make it unlikely that flows reach a WUS.

 Ephemeral and intermittent drainages where the channel ends in a closed basin 

and it is unlikely that flows reach a WUS.

Currently, the channel above these breaks in jurisdiction would be considered isolated

and/or lack a significant nexus to a WUS, even if portions of the channel above the 

breaks in jurisdiction had a bed and banks or an OHWM. These situations occur with 

enough frequency in the arid West that elimination of the criteria for isolation associated 

with breaks in jurisdiction and making ephemeral and intermittent drainages 

jurisdictional by rule would substantially increase the scope of CWA jurisdiction in the 

arid West.

Many ephemeral and intermittent drainages in the arid West have a discontinuous bed 

and banks and/or OHWMs (discontinuous features). These discontinuous features are the 

result of infrequent flow events and are an indicator that such drainages may not have 

sufficient or consistent flow to connect to a WUS or physically, chemically, or 

biologically affect the integrity of a WUS. The Corps recognizes this common situation 

in Section III.B of the Approved JD Form discussed above that states: “[W]here there is a 

break in the OHWM that is unrelated to the waterbody’s flow regime” (i.e., the Corps 

considers how flow regime relates to jurisdictional features in determining isolation). In 

many situations under current guidance and policy, the discontinuous nature of these 

features is substantial enough to “isolate” and render the drainages nonjurisdictional 

above these substantial breaks in jurisdictional features. Under the proposed rule, a water 

that otherwise qualifies as a tributary does not lose its status as a tributary if, for any 

length, there are one or more man-made breaks, or one or more natural breaks so long as 

a bed and bank and OHWM can be identified upstream of the break. As proposed, the 

rule would not consider any break in jurisdictional features, no matter how extensive, as 

justification to consider reaches above the break in features to be nonjurisdictional. This 

approach fails to consider the length of the break in relationship to flows that form the 

features to the overall drainage or the characteristics of the drainage.
Clean Water Rule Response to Comments – Topic 8: Tributaries

517

For example, consider a 20-mile-long ephemeral drainage with an OHWM and bed and 

banks for its lower 5 miles with a 10-mile break in jurisdictional features, with the 

remaining upper 5 miles of drainage with intermittent indicators of an OHWM and a bed 

and banks. This drainage most certainly has a different probability of connection and 

physically, chemically, or biologically affecting the integrity of a WUS than the same 

length of an ephemeral drainage with a 1⁄8-mile break in jurisdictional features. As 

proposed, the rule has no approach for making such distinctions in determining the 

jurisdictional status of ephemeral and intermittent drainages. Unfortunately, such 

examples are not the exception. Ephemeral and intermittent drainages with substantial 

breaks in jurisdictional features occur with enough frequency over the landscape of the 

arid West to render the proposed rule’s approach arbitrary.

Substantial breaks in jurisdiction (discontinuous features) can also be indicative of an 

ephemeral or intermittent drainage with subsurface flow that occurs within the alluvium 

of the channel. The alluvial flow may be lost before reaching a WUS due to evaporation, 

consumptive use by riparian and wetland vegetation, diversions by shallow wells, and 

possibly infiltration to a suballuvial (deep ground water) aquifer. Dryland channels 

experience high rates of downstream transmission losses because of the porous nature of 

typical channel bed materials (Graf 1988). The discontinuous features may also be 

associated with channels with gradients that flatten and/or broaden.

The proposed rule states that “[N]on-jurisdictional geographic features (e.g., nonwetland 

swales, ephemeral upland ditches) may still serve as a confined surface hydrological 

connection between an adjacent wetland or water and a traditionally navigable water, 

interstate water or the territorial sea, provided there is an actual exchange of water 

between those waters, and the water is not lost to deep groundwater through infiltration 

(i.e., transmission losses).”

Although not explained in the proposed rule, in practice, the above criteria would only 

apply to ephemeral or intermittent drainages, ditches, canals, and wetlands because rivers 

and perennial streams would have defined perennial surface connections to a WUS. This 

approach to negating the effect of substantial breaks in jurisdiction of ephemeral and 

intermittent drainages has several problems. First, as discussed above, substantial breaks 

in jurisdiction (discontinuous features) can be indicative of an ephemeral or intermittent 

drainage with flows that tend to be lost from the channel alluvium and not reach a WUS. 

Loss of ground water from these drainages rarely produces a confined or defined 

connection to a WUS. More commonly in the arid West, the ground water in an 

ephemeral or intermittent drainage adds to the soil moisture in the immediate vicinity 

and/or evaporates or is transpired. The water is lost, but not to “deep ground water.” The 

proposed rule needs to define “deep ground water.” Throughout portions of the arid 

West, “deep ground water” means ground water that does not reach a river or stream or 

its associated alluvial aquifer and is referred to as nontributary ground water. It would be 

very unusual in the arid West for the surface flows of ephemeral or intermittent drainages 

to contribute significant volumes of water to deep ground water. (p. 9-12)

Agency Response: As discussed further in summary response 8.1, 8.1.1 and 8.1.2 

above and in the TSD and Connectivity report the science and agency experience 

support the decision to determine by rule that all waters meeting the definition of 

tributary are “waters of the United States,” including ephemeral streams. The final 
Clean Water Rule Response to Comments – Topic 8: Tributaries

518

rule further establishes that for a ditch or other feature to be jurisdictional as a 

tributary it must have bed and banks and an OHWM and flow directly or indirectly 

into a (a)(1) – (a)(3) water. Many of the features outlined by the commenter would 

fail to satisfy one or both of these requirements, and would therefore not be a 

“tributary” under the final rule. The agencies have long recognized the unique 

hydrologic and climatic circumstances found in the arid west and have even 

developed a OHWM manual specifically to address these challenges. This method 

uses stream geomorphology and vegetation response to the dominant stream 

discharge and represents the most consistent and repeating pattern associated with 

“ordinary” events representing OHW in the arid west, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx. See also the summary responses 8.1.2: Use of OHWM 

inappropriate/appropriate – will lead to over/under coverage of features above and 

summary response 8.1.1. 

8.392 The proposed rule should define the characteristics that distinguish non-jurisdictional 

areas and features (e.g., uplands, gullies, rills and vegetated swales) from jurisdictional 

areas and features. This guidance is particularly important in the arid West where the 

differences between an ephemeral drainage and gullies and rills can be minor. (p. 23)

Agency Response: See the summary response for Section 8.4, particularly the subsection titled, “Distinction between an ephemeral water and a non-jurisdictional 

gulley, rill or non-wetland swale.”

California Department of Transportation, Division of Environmental Analysis (Doc. #19538)

8.393 The discussion of rills and gullies on pages 22218 and 22219 will cause additional 

confusion as it describes steep headwater streams, which would be jurisdictional, in the 

same terms as it defines gullies, which are excluded from jurisdiction. Caltrans 

recommends that only features with an identifiable OHWM be considered a stream or 

tributary and that features that are not wetlands and lack an OHWM be excluded from 

jurisdiction by rule. (p. 3)

Agency Response: The definition of “tributary” in the final rule requires that flow 

must be of sufficient volume, frequency, and duration to create the physical 

characteristics of bed and banks and an ordinary high water mark. If a water lacks 

sufficient flow to create such characteristics, it is not considered “tributary” under 

this rule. The agencies are aware that terms such as “gully” and “rill” may have 

different meanings throughout the country. Therefore, by grounding the definition 

of “tributary” in the final rule to the above referenced specific physical features, the 

agencies believe that confusion regarding whether a feature is a “tributary” or a 

non-jurisdictional “erosional feature” will be minimal. 

Arizona Chamber of Commerce and Industry (Doc. #14639)

8.394 Although the proposed rule seeks to regulate ephemeral tributaries while exempting 

“gullies” and “rills” the rule proposes to distinguish between regulated tributaries and 

exempt gullies and rills using the presence of an ordinary high water mark. This is an 
Clean Water Rule Response to Comments – Topic 8: Tributaries

519

unworkable and improper method for attempting to distinguish between jurisdictional and 

non-jurisdictional waters in the arid West. (p. 2)

Agency Response: The definition of “tributary” in the final rule requires that flow 

must be of sufficient volume, frequency, and duration to create the physical 

characteristics of bed and banks and an ordinary high water mark. If a water lacks 

sufficient flow to create such characteristics, it is not considered “tributary” under 

this rule. By grounding the definition of “tributary” in the final rule to the above 

referenced specific physical features, the agencies believe that confusion regarding 

whether a feature is a “tributary” or a non-jurisdictional “erosional feature” will be 

minimal. 

Aluminum Association (Doc. #15388)

8.395 ...because this proposed rule is vague on the actual starting point of WUS, it could be 

interpreted to pull any storm water that leaves a puddle into the scope of WUS. As 

explained in the preamble (on p. 22218), the Agencies have decided to continue to 

exclude “puddles” from the list of waters that are generally not jurisdictional because 

“‘puddles’ is not a sufficiently precise hydrologic term or a hydrologic feature capable of 

being easily understood.” Because the term is not specifically included in the excluded 

waters list and because the proposed rule is so broad, it is possible that storm water that 

leaves a puddle may still be considered WUS. Also, because the proposed scope of WUS 

is broad, storm water that drains from an empty field at an industrial complex that enters 

a ditch through a series of small gullies or through sheet flow may also now be WUS and 

thus potentially subject to water quality criteria even though no industrial activity is or 

was conducted in this area. Another concern is that this type of water may traverse many 

features prior to entering an engineered storm water treatment system such as a pocket 

wetland, grassed buffer zone, or rip-rap channel. Under the Proposed Rule, this water 

could potentially be subject to water quality criteria prior to entering such a system thus 

leaving the discharger in a quandary as to where such treatment should be located and 

what level of treatment would be required.

Another potential concern is the use of storm sewers to remove storm water from 

industrial areas. The preamble states:

“the upper limit of a tributary is established where the channel begins...”551

“A water that otherwise qualifies as a tributary under the proposed definition does 

not lose its status as a tributary if, for any length, there are one or more man-made 

breaks such as bridges, culverts, pipes, or dams.”552

As an example, consider a material storage area, which contains material storage racks or 

other industrial supplies, and from which storm water drains to a series of small gullies 

that drain to a storm sewer and then to a ditch. Under this broad definition, each of these 

drainage sequences could be potentially designated as jurisdictional under the proposed 

rule.

 

551 79 Fed. Reg. 22188, 22202 (Apr. 21, 2014).

552 Id.
Clean Water Rule Response to Comments – Topic 8: Tributaries

520

Another part of the explanation of tributary within the preamble states:

“Also, in many intermittent and ephemeral tributaries, including dry-land systems 

in the arid and semi-arid west, OHWM553 indicators can be discontinuous within 

an individual tributary due to the variability in hydrologic and climatic 

influences.”554

It appears that this language is reflecting that a storm water ditch that may dry prior to 

entering another water body, is still considered to be a “tributary” and consequently a 

WUS. Delineation should be made that WUS does not begin for storm water until it 

enters a properly defined tributary to a navigable waterway. Tributaries should be 

narrowly defined to have the normal bed, bank, and high water mark, and consistently 

(more than 6 months per year), discharge to a traditional navigable waterway. (p. 6-7)

Agency Response: In response to public comments, puddles are now explicitly 

excluded in paragraph (b) of the final rule. The definition of “tributary” in the final 

rule requires that flow must be of sufficient volume, frequency, and duration to 

create the physical characteristics of bed and banks and an ordinary high water 

mark. If a water lacks sufficient flow to create such characteristics, it is not 

considered “tributary” under this rule. Sheet flow is therefore not grounds to assert 

jurisdiction under the final rule. Stormwater control features constructed in dry 

land and ditches with less than perennial flow, unless they are a relocated tributary 

or excavated in a tributary, are also explicitly excluded in paragraph (b).

National Association of Manufacturers (Doc. #15410)

8.396 Further, the agencies’ proposed jurisdiction over ephemeral streams and some ditches as 

“tributaries” cannot be reconciled with its recognition that comparable bodies of water 

have no “significant nexus” to traditional navigable waters. As a matter of basic 

hydrology, there is no meaningful distinction between an ephemeral stream and “gullies, 

rills, and nonwetland swails” with respect to their impact on the quality of any traditional 

navigable waters to which they ultimately connect. Ephemeral streams are categorically 

treated as a “tributaries” while “gullies, rills, and nonwetland swails” are categorically 

deemed non-tributaries even though they “may contribute flow” to downstream waters 

and ultimately traditional navigable waters, 79 Fed. Reg. at 22204; see also id. at 22218-

19.

The proposed rule provides no explanation for not likewise exempting ephemeral 

streams, other than the need to “dra[w] lines.” Id. at 22218. But the fact that an agency 

may have to draw lines is not a license to draw inconsistent and arbitrary lines. See 

Westar Energy, Inc. v. FERC, 473 F.3d 1239, 1241 (D.C. Cir. 2007) (“A fundamental 

norm of administrative procedure requires an agency to treat like cases alike. If the 

agency makes an exception in one case, then it must either make an exception in a similar 

case or point to a relevant distinction between the two cases.”). The very reason that the 

proposed rule provides for finding that “gullies, rills, and nonwetland swails” are 

generally not “waters of the United States”—that these types of features have only 

 

553 OHWM means ordinary high water mark.

554 79 Fed. Reg. at 22202.
Clean Water Rule Response to Comments – Topic 8: Tributaries

521

intermittent flow of water, 79 Fed. Reg. at 22218-19—applies just as equally to many 

streams that are “tributaries” but are always deemed to be “jurisdictional” under the 

proposal. (p. 16-17)

Agency Response: The agencies disagree that there is not distinction between 

ephemeral tributaries and erosional features like gullies, rills and non-wetland 

swales. See the summary response for Section 8.4, particularly the sub-section 

titled, “Distinction between an ephemeral water and a non-jurisdictional gulley, rill 

or non-wetland swale.” In addition, see the summary response for “Relevance of 

Flow Regime” in section 8.1.1 of this RTC, particularly subsections on jurisdiction 

over intermittent and ephemeral waters and the legality of asserting jurisdiction 

over ephemeral waters. The agencies’ position in regard to tributaries is rooted in a 

science-based conclusion that such waters have a significant nexus either 

individually or in the aggregate with traditional navigable waters, interstate waters, 

and the territorial seas. Section VII of the Technical Support Document discusses 

the science supporting the agencies’ conclusion.

American Council of Engineering Companies (Doc. #15534)

8.397 Ephemeral tributaries should be differentiated from erosion features as natural or manaltered drainages with indicators including the existence an ordinary high water mark, 

occurrence in natural topographic low (i.e., natural watershed landscape position), and 

soils developed through both alternating erosional and depositional conditions (i.e., 

sediment transfer). The proposed rule should clearly state that erosional features do not 

have a significant nexus and describe how to differentiate those features from ephemeral 

tributaries (i.e., past land use information, lack of consistent visual confirmation of an 

ordinary high water mark in historic aerials, indicators of erosional conditions only, and 

lack of alternating sediment depositional segments). (p. 4).

Agency Response: See the summary response for Section 8.4, particularly the subsection titled, “Distinction between an ephemeral water and a non-jurisdictional 

gulley, rill or non-wetland swale.” Erosional features like gullies, rills and nonwetland swales are explicitly excluded from consideration as waters of the United 

States in paragraph (b) of the final rule. Section IV(F) of the preamble to the final 

rule describes a number of tools that the agencies and the public may use to help 

determine whether a water meets the definition of “tributary” or is instead a nonjurisdictional feature.

Business Council of Alabama (Doc. #15538)

8.398 The proposed rule mentions the need to make "case-specific analysis" in many situations 

which conflicts with their goal of providing "greater regulatory certainty" in the final 

rule. The types of situations that may have to be submitted to the Corps include, but are 

not limited to, the following:

a. A pool of open waters or wetlands outside of the floodplain that is connected to 

WOTUS via a rill. At this time it would be more likely be determined these are isolated, 

not jurisdictional waters and not WOTUS. If in fact a "rill" or rills are the only conduit 

source to downstream waters then it seems we have an obvious overreach by the 

EPA/Corps. A rill is not a water of the U.S or a wetland. If a "rill" is used as a physical 
Clean Water Rule Response to Comments – Topic 8: Tributaries

522

geographic feature to determine a connection to WOTUS then we have an example of 

unreasonable proximity. EPA has stated in the proposed regulations they are seeking for 

the final rule to have "greater regulatory certainty" over what is and what is not 

jurisdictional by rule. The fact that the proposed rule attributes rills as having a 

hydrological connection to "other waters" and this example could be used to show a 

"significant nexus" will not result in their goal to have the final rule clarify with "greater 

regulatory certainty" what is and is not jurisdictional. Rills often times develop due to the 

lack of or improper implementation of BMPs resulting from on-site construction activity 

at a project site. These rills could easily be misconstrued to have some "connection" to 

some wetlands or ponded areas that are up-gradient which contribute little or no surface 

water to WOTUS. It is apparent that the EPA/Corp s is using the most minor of all 

possible hydrological connections to assert their jurisdiction. (p. 3)

Agency Response: The agencies disagree that efforts to obtain accurate site 

specific information before making a jurisdictional determination conflicts with the 

goal of the final rule to provide greater regulatory certainty. Numerous provisions 

of the final rule enhance this certainty by, for example, defining “tributary” for the 

first time and specifically excluding many features that before the final rule have 

only “generally” been considered by the agencies as non-jurisdictional.

GBMC & Associates (Doc. #15770)

8.399 ...Determination of ordinary high water features, including bed and bank, is subjective to 

interpretation and provide a source of confusion amongst the agencies, districts, 

consultants, and the general population. The agencies should develop a mechanism for 

training or adopt a protocol from a reputable organization that would train all involved 

parties to identify ordinary high water features, particularly bed and bank, and that would 

differentiate between stream features and erosional features such as gullies and scour 

marks. One of the goals of the training should be to ensure a consistent interpretation of

what a tributary is. (p. 6)

Agency Response: The term “ordinary high water mark” has been defined in 

Corps regulations since 1986, and used by Corps Districts nationwide to determine 

the lateral limits of jurisdiction over non-tidal water bodies for the CWA section 404 

permitting program. See the summary response for Section 8.4, particularly the 

sub-section titled, “Need for additional factors and specific guidance and 

methodology....” In regards to training support, the agencies plan to continue to 

build on the more than a decade of effort spent improving the consistency and rigor 

of OHWM identifications by developing and publishing technical manuals 

explaining OHWM and regional considerations, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates.

Federal Water Quality Coalition (Doc. #15822.1)

8.400 8. Gullies and rills.

Under the proposed rule, gullies and rills would not be jurisdictional. However, neither 

term is defined. According to the preamble: “Gullies are relatively deep channels that are 
Clean Water Rule Response to Comments – Topic 8: Tributaries

523

ordinarily formed on valley sides and floors where no channel previously existed.” “Rills 

are formed by overland water flows eroding the soil surface during rain storms.”555 By 

contrast, “ephemeral streams” often would be jurisdictional. But again, although the term 

is used 75 times, the preamble does not define it. EPA’s Draft Connectivity Report 

defines “ephemeral stream” as: “A stream or river that flows briefly in direct response to 

precipitation; these channels are above the water table at all times.”556 As a result, gullies 

and rills could be considered ephemeral streams. All are erosion features that carry water 

only when it rains. The agencies recognize they have not clearly distinguished between 

these features, even though one is categorically jurisdictional and the others are 

categorically exempt.557 Even if not jurisdictional themselves, gullies and rills may be 

used to establish a connection and turn isolated water into jurisdictional water.558 The 

expansion of jurisdiction to reach ephemeral streams, the lack of definitions, and the use 

of gullies and rills to make jurisdictional determinations have caused significant 

uncertainty about the status of these features. (p. 20)

Agency Response: The definition of “tributary” in the final rule requires that flow 

must be of sufficient volume, frequency, and duration to create the physical 

characteristics of bed and banks and an ordinary high water mark. If a water lacks 

sufficient flow to create such characteristics, it is not considered “tributary” under 

this rule. By grounding the definition of “tributary” in the final rule to the above 

referenced specific physical features, the agencies believe that confusion regarding 

whether a feature is a “tributary” or a non-jurisdictional “erosional feature” will be 

minimal. See the summary response for Section 8.4, particularly the sub-section 

titled, “Distinction between an ephemeral water and a non-jurisdictional gulley, rill 

or non-wetland swale.” In addition, see the summary response for “Relevance of 

Flow Regime” in section 8.1.1 of this RTC, particularly subsections on jurisdiction 

over intermittent and ephemeral waters and the legality of asserting jurisdiction 

over ephemeral waters. The agencies’ position in regard to tributaries is rooted in a 

science-based conclusion that such waters have a significant nexus either 

individually or in the aggregate with traditional navigable waters, interstate waters, 

and the territorial seas. Section VII of the Technical Support Document discusses 

the science supporting the agencies’ conclusion.

8.401 9. Non-wetland swales.

Non-wetland swales are not jurisdictional. However, it is difficult to distinguish a swale 

from an ephemeral stream. According to the agencies: “Swales are distinct from streams 

in that they are non-channelized, shallow trough-like depressions that carry water mainly 

 

555 79 Fed. Reg. at 22218.

556 See Connectivity of Streams and Wetlands to Downstream Waters: A Review and Synthesis of the Scientific

Evidence (September 2013 External Review Draft, EPA/600/R–11/098B) (hereinafter, “Draft Connectivity

Report”), at Glossary.

557 “The agencies request comment on how they could provide greater clarity on how to distinguish between

erosional features such as gullies, which are excluded from jurisdiction, and ephemeral tributaries, which are 

categorically jurisdictional.” 79 Fed. Reg. at 22219.

558 “Examples of confined surface water hydrologic connections that demonstrate adjacency are swales, gullies, and 

rills.” 79 Fed. Reg. at 22210. It appears that the skidder rut that was described in Congressional testimony could 

meet this definition and be used to establish jurisdiction. See supra n. 16.
Clean Water Rule Response to Comments – Topic 8: Tributaries

524

during rainstorms or snowmelt.” 79 Fed. Reg. at 22219. Like gullies and rills, the 

agencies propose to use non-wetland swales to establish connections that would make 

other water jurisdictional. EPA recognizes that the distinction between a nonjurisdictional swale and a jurisdictional ephemeral stream is very vague. Id. As a result, 

landowners will not know if a swale on their property is considered a jurisdictional water 

or not. As with gullies and rills, the expansion of jurisdiction to reach ephemeral streams, 

the lack of definitions, and the use of non-wetland swales to make jurisdictional 

determinations have caused significant uncertainty about the status of these features. (p 

20-21)

Agency Response: The definition of “tributary” in the final rule requires that flow 

must be of sufficient volume, frequency, and duration to create the physical 

characteristics of bed and banks and an ordinary high water mark. If a water lacks 

sufficient flow to create such characteristics, it is not considered “tributary” under 

this rule. The agencies believe that non-wetland swales, like other erosional 

features, lack sufficient volume, frequency, and duration of flow to create the 

physical characteristics of bed and banks and an ordinary high water mark. See the 

summary response for Section 8.4, particularly the sub-section titled, “Distinction 

between an ephemeral water and a non-jurisdictional gulley, rill or non-wetland 

swale.” In addition, see the summary response for “Relevance of Flow Regime” in 

section 8.1.1 of this RTC, particularly the subsection on jurisdiction over 

intermittent and ephemeral waters. 

Water Advocacy Coalition (Doc. #17921.1)

8.402 2. The tributary definition does not provide clarity, but creates confusion.

In addition to its broad reach, the tributary definition is problematic because it relies on 

vague language and confusing concepts, including the following:

...

 Tributaries versus erosional features: The preamble acknowledges the difficulty in 

distinguishing between tributaries, which are categorically jurisdictional under the 

proposed rule, and erosional features, such as gullies, which are categorically 

excluded from jurisdiction. 79 Fed. Reg. at 22,218. Both erosional features and 

ephemeral drainages are characterized as small features that typically only carry 

water during precipitation events. How will regulators distinguish between 

ephemeral drainages and gullies or rills? Given the difficulty in distinguishing 

between these two types of features, the agencies’ assertion of jurisdiction over 

one feature but not the other is arbitrary and not supported by science. (p. 47, 49)

Agency Response: The definition of “tributary” in the final rule requires that flow 

must be of sufficient volume, frequency, and duration to create the physical 

characteristics of bed and banks and an ordinary high water mark. If a water lacks 

sufficient flow to create such characteristics, it is not considered “tributary” under 

this rule. The agencies believe that erosional features lack sufficient volume, 

frequency, and duration of flow to create the physical characteristics of bed and 

banks and an ordinary high water mark. See the summary response for Section 8.4, 

particularly the sub-section titled, “Distinction between an ephemeral water and a 
Clean Water Rule Response to Comments – Topic 8: Tributaries

525

non-jurisdictional gulley, rill or non-wetland swale.” In addition, see the summary 

response for “Relevance of Flow Regime” in section 8.1.1 of this RTC, particularly 

the subsection on jurisdiction over intermittent and ephemeral waters The agencies’ 

position in regard to tributaries is rooted in a science-based conclusion that such 

waters have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

conclusion.

8.403 3. There is confusion over what is an erosional feature that is excluded.

The agencies propose to exclude gullies, rills, and non-wetland swales, but do not 

propose definitions of those terms. The preamble states that the agencies specifically seek 

comment on “how to distinguish between erosional features, such as gullies, which are 

excluded from jurisdiction, and ephemeral tributaries, which are categorically 

jurisdictional.” 79 Fed. Reg. at 22,219. Again, this raises many questions:

 How are regulators and regulated entities to identify gullies, rills, and nonwetland swales?

 What is the difference between erosional features and ephemeral drainages? The 

agencies do not provide any scientific basis for distinguishing between them.

 Indeed, if these features are so similar, why are erosional features categorically 

excluded and ephemeral drainages categorically jurisdictional? Neither should be 

jurisdictional.

The confusion over when these predominantly dry features are excluded erosional 

features will likely result in a substantial number of requests from the regulated 

community to verify that a particular feature is erosional. Given the subjective nature of 

erosion, to obtain regulatory certainty, it will likely be deemed too risky for the regulated 

public to decide on their own that only non-jurisdictional erosion exists at their site. 

Without further clarification of this issue, the Corps and EPA should expect a large 

number of future requests to verify the presence of an erosional feature versus a 

potentially regulated tributary.

Even more confusingly, the reasons given in the preamble for not listing “puddles” as 

“waters of the United States” seem similarly applicable for ephemeral drainages. The 

preamble states that puddles are not waters of the United States because a puddle “exists 

for only a brief period of time before the water in the puddle evaporates.” 79 Fed. Reg. at 

22,218.176 But the same is often true of ephemeral drainages, which are categorically 

jurisdictional under the proposed rule. Why are ephemeral drainages jurisdictional, and 

puddles are not? The agencies ask for comment on the distinction between these features 

and ephemeral and intermittent streams, but they do not provide much information on 

which to comment. The agencies should exclude ephemeral streams from jurisdiction, as 

well as erosional features like gullies, rills, and non-wetland swales. This would eliminate 

substantial confusion over the distinction between erosional features and ephemeral 

drainages. (p. 72-73)

Agency Response: The definition of “tributary” in the final rule requires that flow 

must be of sufficient volume, frequency, and duration to create the physical 
Clean Water Rule Response to Comments – Topic 8: Tributaries

526

characteristics of bed and banks and an ordinary high water mark. If a water lacks 

sufficient flow to create such characteristics, it is not considered “tributary” under 

this rule. The agencies believe that erosional features lack sufficient volume, 

frequency, and duration of flow to create the physical characteristics of bed and 

banks and an ordinary high water mark. See the summary response for Section 8.4, 

particularly the sub-section titled, “Distinction between an ephemeral water and a 

non-jurisdictional gulley, rill or non-wetland swale.” In addition, see the summary 

response for “Relevance of Flow Regime” in section 8.1.1 of this RTC, particularly 

the subsection on jurisdiction over intermittent and ephemeral waters. The 

agencies’ position in regard to tributaries is rooted in a science-based conclusion

that such waters have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

conclusion. The agencies have never considered puddles to meet the minimum 

standard for being a water of the United States.

National Association of Home Builders (Doc. #19540)

8.404 4. The Proposed Rule Draws an Arbitrary Distinction between Erosional Features 

and Ephemeral Drainages.

The Agencies propose to exclude gullies, rills, and non-wetland swales, and yet do not 

provide definitions for any of those terms. The preamble states that the Agencies 

specifically seek comment on “how to distinguish between erosional features, such as 

gullies, which are excluded from jurisdiction, and ephemeral tributaries, which are 

categorically jurisdictional.”559 Indeed, this raises many questions:

 How are regulators and the regulated community to identify gullies, rills, and 

nonwetland swales?is the difference between erosional features and ephemeral 

drainages? The Agencies provide no scientific basis for distinguishing between 

them.

 Indeed, if these features are so similar, why are erosional features categorically 

excluded and ephemeral drains are categorically jurisdictional? After all, all rivers 

and streams exist because the force of flowing water has eroded sediment 

downstream to form a channel. Dr. Luna Leopold, one of the most noted river 

scientist of the modern era, put it best when he and his colleagues described rivers 

as the “gutters down which flow the ruins of continents.”560

The different treatment of these predominantly dry features appears to be entirely 

arbitrary. The Agencies should exclude ephemeral streams from jurisdiction as well as 

erosional features like gullies, rills, and non-wetland swales. Indeed, the USGS even 

recognizes gullies as “synonymous with ephemeral [streams].”561 (p. 117)

 

559 Id. at 22,219.

560 Leopold, L.B., M.G. Wolman, J.P. Miller. Fluvial Processes in Geomorphology. San Francisco: Freeman, 1964.

Print.

561 USGS National Hydrography Dataset Newsletter Vol. 5, No. 4, February 2006 by Jeff Simley.
Clean Water Rule Response to Comments – Topic 8: Tributaries

527

Agency Response: The agencies do not believe that the distinction between 

ephemeral tributaries and erosional features is arbitrary. See the summary 

response for Section 8.4, particularly the sub-section titled, “Distinction between an 

ephemeral water and a non-jurisdictional gulley, rill or non-wetland swale.” In 

addition, see the summary response for “Relevance of Flow Regime” in section 8.1.1 

of this RTC, particularly the subsection on jurisdiction over intermittent and 

ephemeral waters. The agencies’ position in regard to tributaries is rooted in a 

science-based conclusion that such waters have a significant nexus either 

individually or in the aggregate with traditional navigable waters, interstate waters, 

and the territorial seas. Section VII of the Technical Support Document discusses 

the science supporting the agencies’ conclusion.

Pennsylvania Coal Alliance (Doc. #13074)

8.405 h. Erosional features and swales – As acknowledged in the Proposed Rule, it is difficult 

to distinguish between an erosional feature or gully and a jurisdictional water, with 

potentially the only difference being the length of time that the features have existed.20 

This distinction is even more difficult with the inclusion of all ephemeral streams as 

tributaries. The PCA requests clarification of the distinction between these features to 

minimize confusion and subjective determinations. (p. 15-16)

Agency Response: See the summary response for Section 8.4, particularly the subsection titled, “Distinction between an ephemeral water and a non-jurisdictional 

gulley, rill or non-wetland swale.”

Newmont Mining Corporation (Doc. #13596)

8.406 1. Status under the Current Regulations

Some, but certainly not most, of the ephemeral drainages and intermittent streams on 

Newmont’s properties have been deemed jurisdictional by the Corps. In determining the 

jurisdictional status of these streams, in recent years, the Corps has relied on the 

framework set forth in the 2008 Guidance. Pursuant to that Guidance, streams that flow 

for less than three months per year (which would include most of the ephemeral 

drainages and intermittent streams on Newmont’s properties) are not considered per se 

jurisdictional. Rather, the Corps must determine on a case-by-case basis whether these 

streams, considered alone (and not in combination with other “similarly situated” streams 

in the area), have a significant impact on the chemical, physical, and biological integrity 

of a TNW. In making this determination, the Corps looks at the frequency and duration of 

flow of the drainage in question, the distance to the nearest TNW, evaporation and 

precipitation rates in the area, and other factors potentially relevant to whether the 

drainage in question significantly impacts a TNW. Importantly, pursuant to the 2008 

Guidance, “small washes characterized by low volume, infrequent, or short duration 

flow,” would generally not be deemed jurisdictional waters. See 2008 Guidance at 1, 8, 

11. This describes to a tee the vast majority of the ephemeral and intermittent drainages 

on Newmont’s properties. (p. 28-29)

Agency Response: Section I of the Technical Support Document, discusses the 

historic scope of the existing regulatory definition of waters of the United States. 

See the summary response for “Relevance of Flow Regime” in section 8.1.1 of this 
Clean Water Rule Response to Comments – Topic 8: Tributaries

528

RTC, particularly the subsection on jurisdiction over intermittent and ephemeral 

waters. The agencies’ position in regard to tributaries is rooted in a science-based 

conclusion that such waters have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion.

Arizona Mining Association (Doc. #13951)

8.407 The “contribute flow” standard, particularly as applied to arid environments, fails to 

account for the fact that even when there might be a limited physical connection between 

an ephemeral wash and a TNW, the wash functions solely as a potential physical 

conveyance of water and potential sediment similar to other erosional features such as 

gullies and rills. However, under the proposed rule, gullies and rills are exempt while 

ephemeral washes, if determined to meet the definition of a tributary, will be subject to 

CWA jurisdiction. Remarkably, the agencies do not even attempt to provide any 

workable method for distinguishing between potentially jurisdictional tributaries and 

non-jurisdictional gullies and rills. Rather, the agencies generically suggest that gullies 

and rills are newer in geologic time and “typically lack an OHWM.” 79 Fed. Reg. at 

22218. However, such a generic explanation is not workable or even meaningful for the 

arid West. As noted above, erosional channels/washes can form during a single “flashy” 

storm event in arid landscapes and appear to have OHWM indicators, even though the 

channel is newly created and not representative of “ordinary” flow. There is no logical 

reason or basis in the proposed rule for attempting to distinguish between dry desert 

washes in the arid West and exempt gullies and rills, making the proposed rule legally 

and scientifically flawed. (p. 13)

Agency Response: See the summary response for Section 8.4. See the summary 

response for “Relevance of Flow Regime” in section 8.1.1 of this RTC, particularly 

the subsection on jurisdiction over intermittent and ephemeral waters. The 

agencies’ position in regard to tributaries is rooted in a science-based conclusion

that such waters have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

conclusion.

8.408 Features with discontinuous OHWMs also are common in arid landscapes. Pursuant to 

the proposal (33 C.F.R. § 328.3(c)(5)), lack of a continuous OHWM does not apparently 

foreclose a presumed tributary relationship so long as a bed and banks and an ordinary 

high water mark can be identified upstream of the break. In some cases, there may be a 

relatively clear connection between upstream and downstream portions of the same 

tributary despite intervening absence of an OHWM (e.g., where water is conveyed briefly 

through a culvert). In other cases, however, the connection may be less clear or 

nonexistent. One such example is a small channel on relatively steep slopes that 

subsequently enters a flat area and essentially dissipates as a defined channel. The small 

channel in this example evidences indicia of flow, and it could be regulated by the rule. 

There may be other channels with what the agencies consider to be an OHWM 

downstream of the point where the original channel dissipates, but there may not be any 
Clean Water Rule Response to Comments – Topic 8: Tributaries

529

true connection between the upstream and downstream features. In such a case, the 

channel that dissipates should not be considered a regulated tributary (or should qualify 

as an exempt gully or rill), but it is not clear if this would be the case under the proposal. 

(p. 12-13)

Agency Response: See the summary responses for Section 8.4 and 8.3.

Freeport-McMoRan Inc. (Doc. #14135 and Doc. #14135.1)

8.409 VI. As applied to the arid west, the Proposed Rule would deem numerous gullies 

and rills to be categorically jurisdictional tributaries.

The Proposed Rule purports to maintain the established practice of excluding gullies and 

rills from the scope of jurisdictional waters.562 The Proposed Rule concludes that gullies 

and rills are not waters of the United States because “the agencies have by longstanding 

practice generally considered [these features] not to be ‘waters of the United States.’”563

As a result, under the Agencies’ formulation a key dividing line between jurisdictional 

and non-jurisdictional waters will be the point where a tributary becomes a gulley or a 

rill. The Proposed Rule recognizes the difficulty in determining where tributaries begin 

even in humid systems and specifically requests comment on how to distinguish between 

jurisdictional tributaries and non-jurisdictional features, such as gullies and rills.564

In the preamble to the Proposed Rule, the only differentiation that the Agencies seem to 

provide between jurisdictional tributaries and non-jurisdictional gullies and rills is that 

gullies and rills “typically lack an OHWM.”565 The preamble further notes that these 

features are distinguished because “time has shaped streams into geographic features 

distinct from gullies and rills.”566 Thus, it seems that the Agencies have determined that 

the distinction between jurisdictional and non-jurisdictional features should be drawn 

where it is possible to locate physical features that are indicative of the establishment of 

equilibrium conditions that create a tributary. However, the Corps’ own work in the arid 

west clearly demonstrates that the presence of ordinary high water marks in arid channels 

does not bear any relationship to anticipated present or future flows.567 Due to the highly 

erodible nature of soils in the arid west, a single flow event could cause erosion that looks 

like an “ordinary” high water mark, meaning that it is the result of an event that is far 

from ordinary.568 As a result, the Agencies logic in distinguishing between jurisdictional 

and non-jurisdictional features based on the presence of an “ordinary” high water mark 

does not hold in the arid west. The inevitable consequence of this fact is that the 

application of the Proposed Rule’s bright-line definition of tributaries will illegally assert 

jurisdiction over non-jurisdictional gullies and rills. In the absence of bright line criteria, 

 

562 79 Fed. Reg. at 22,218.

563 Id.

564 Id. at 22,204.

565 Id. at 22,218.

566 Id.

567 Robert W. Lichvar et al., Distribution of Ordinary High Water Mark (OHWM) Indicators and Their Reliability in

Identifying the Limits of “Waters of the United States” in Arid Southwestern Channels, EDRC/CCREL TR-06-5 

(2006).

568 Technical Comments at 7.
Clean Water Rule Response to Comments – Topic 8: Tributaries

530

we believe the Agencies can and should identify factors defining a sufficient flow to 

traditional navigable waters to be regulable, including magnitude, duration and frequency 

of flow[.] (Doc. #14135, p. 7-8)

Agency Response: The definition of “tributary” in the final rule requires that flow 

must be of sufficient volume, frequency, and duration to create the physical 

characteristics of bed and banks and an ordinary high water mark. If a water lacks 

sufficient flow to create such characteristics, it is not considered “tributary” under 

this rule. The agencies believe that erosional features lack sufficient volume, 

frequency, and duration of flow to create the physical characteristics of bed and 

banks and an ordinary high water mark. See the summary response for Section 8.4, 

particularly the sub-section titled, “Distinction between an ephemeral water and a 

non-jurisdictional gulley, rill or non-wetland swale.” In addition, see the summary 

response for “Relevance of Flow Regime” in section 8.1.1 of this RTC, particularly 

the subsection on jurisdiction over intermittent and ephemeral waters. In addition, 

see summary response 8.1.2. 

8.410 3. Tributaries and Gullies in the Proposed Rule

Anywhere on the face of the earth is hydrologically connected to oceans;569 during rain 

events even gutters on houses have a hydrologic connection to traditional navigable 

waters because they deliver water and any other materials to downstream waters. Thus, at 

the most basic, many features (such as gutters) are simply hydrologic conveyance 

features. Gutters, concrete ditches, pipes, etc. are similarly hydrologic connections to 

downstream waters, but are inert hydrologic conveyance features.

Other hydrologic conveyance features are formed by natural runoff: gullies, washes, 

arroyos, and rills for instance. These are not restricted to arid landscapes, as gullies and 

rills are also prominent in humid areas, particularly agricultural and deforested areas. 

Importantly, the proposed rule exerts jurisdiction over tributaries, but explicitly does not 

exert jurisdiction over gullies or rills. From the proposed rule [underline added]:

The term tributary means a water physically characterized by the presence of a 

bed and banks and ordinary high water mark, as defined at 33 CFR 328.3(e), 

which contributes flow, either directly or through another water, to a water 

identified in paragraphs (a)(1) through (4) of this section.

Based on this definition, the necessary features of a tributary are both

1. Discernible bed and banks and

2. an ordinary high water mark (OHWM)

Along with this definition is the fact that the federal rule excludes gullies and rills, which 

even though they act as a contributor of flow, sediment, and materials to downstream 

waters, are not considered tributaries, and thus not considered jurisdictional waters.

Section J below discusses in more detail the agencies’ proposed rule excluding 

specific waters and features from the definition of ‘‘waters of the United States.’’ 

 

569 This is setting aside internally drained basins.
Clean Water Rule Response to Comments – Topic 8: Tributaries

531

Of importance with respect to tributaries is the exclusion of gullies, rills, nonwetland swales, and certain ditches. These features are not considered tributaries 

under this proposed rule, even though rills and gullies and non-wetland swales (as 

described in Section J), may contribute flow to a tributary in systems with steep 

side slopes.

Agency Response: Exclusions for ditches and other features have been revised 

and clarified for the final rule. As a result, the agencies believe that most ditches 

that are not relocated tributaries or excavated in a tributary will not be 

jurisdictional waters of the United States. The exclusions also indicate that 

erosional features not meeting the definition of “tributary” will not be waters of the 

United States.

8.411 The agencies acknowledge the lack of clarity about tributaries and gullies several times in 

the new rule:

The agencies request comment on how they could provide greater clarity on how 

to distinguish between erosional features such as gullies, which are excluded from 

jurisdiction, and ephemeral tributaries, which are categorically jurisdictional.

The agencies request comment on all aspects of the proposed definition of 

tributaries and in particular on whether and how this definition can be revised to 

provide increased clarity as to the distinction between jurisdictional tributaries, as 

defined, and nonjurisdictional features such as gullies, rills and non-wetland 

swales. The agencies seek comments on how to provide greater regulatory 

certainty as to which specific aquatic features are jurisdictional tributaries, and 

which are not. Commenters should explain how any suggestions are consistent 

with the Clean Water Act, applicable case law, and the scientific literature 

regarding connectivity of aquatic features.

Thus, based on the rhetoric of the proposed rule, it is important to more carefully 

constrain “ephemeral tributaries” and to assess the potential precision (or lack thereof) for 

“Ordinary High Water Marks” in arid landscapes, as such marks are a necessary 

component in the proposed rule for distinguishing between a “tributary” and a “gully” or 

“rill.” It is also important to suggest mechanisms by which federal agencies can provide 

greater certainty in their definitions of these different features, as we will see that 

Ordinary High Water Marks are not reliable indicators of frequency or magnitude of 

flows, or of hydrologic connectivity, in arid landscapes. (Doc. #14135.1, p. 4-6)

Agency Response: See the summary response for Section 8.4. In addition, see the 

summary response for “Relevance of Flow Regime” in section 8.1.1 of this RTC, 

particularly the subsection on jurisdiction over intermittent and ephemeral waters. 

The agencies’ position in regard to tributaries is rooted in a science-based 

conclusion that such waters have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion. The Corps and EPA also plan to continue to 

build on the more than a decade of effort spent improving the consistency and rigor 

of OHWM identifications, especially in the arid west, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254
Clean Water Rule Response to Comments – Topic 8: Tributaries

532

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates.

8.412 5. Implications of Proposed Rule for Arid Landscapes

In sum, due to the processes which shape arid channels, it is unlikely that snapshot 

indicators will be applicable for identifying OHWM in arid landscapes, and thus rapidly 

assessing the extent of jurisdictional waters. Rather than relying on what the Corps’ own 

laboratories find to be inconsistent indicators, it is more viable and defensible to develop 

systematic analyses across a range of relevant processes from which to assess 

jurisdictional waters or, more preferably and more realistically, to use empirical data to 

establish hydrological connections, along with establishing relationships between 

hydrology and geomorphic patterns, e.g., frequency-magnitude of flow events and their

relationships with geomorphic patterns and forms on the landscape. Given the wide 

variability from site-to-site (see case study below), such empirical data would need to be 

collected at fairly local scales while such relationships are being developed and tested to 

be applicable locally.

The current approach to mapping claimed tributaries based on the OHWM570 does not 

appear to be in conflict with the proposed rule, nor do there appear to be aspects of the 

proposed rule that would merit a change in the current regulatory approach to 

jurisdictional waters as has been used in the Los Angeles District. Instead, in the absence 

of reliable bright line indicators, the practice appears to be that the “significant nexus” 

test is used to distinguish, somewhat arbitrarily, between claimed “tributaries” without 

flow and those where flow may be more defensibly supported. In fact, given the admitted 

and documented uncertainty by Corps researchers as described above, the current 

reliance in the Approved Jurisdictional Determination on OHWM may be unmerited, and 

where OHWMs are present, represent too expansive of an extent of jurisdictional waters. 

At a minimum, the agencies’ reliance on OHWM in arid landscapes is a tenuous basis for 

distinguishing tributaries from gullies or rills, and thus a tenuous basis for asserting 

jurisdiction over a particular feature. When OHWMs are identified, we can conclude that 

any jurisdictional waters—meaning waters in which there is an ordinary occurrence of 

flow—are a geographic subset of that area, and likely a very small subset. That is, certain 

waters with an OHWM should not be jurisdictional. As a result, both the current 

approach in the Los Angeles District and the proposed definition of tributary will result in 

a mapped identification of tributary and determination of jurisdictional waters that is too 

broad.

Distinguishing between gullies and tributaries for regulatory purposes in arid landscapes 

will be plagued with uncertainty. The Corps recognized this in 2004, when they stated 

that “Whatever approach is taken to delineate the OHWM [in arid regions], the transitory 

nature of desert rivers must be recognized and the flexibility provided to adjust OHWM 

delineations over time.”571

In lieu of readily available rapid indicators, a refined regulatory approach to the 

determination of jurisdictional waters in the arid west requires data at the relevant scale 

 

570 Approved Jurisdictional Determination Form, Los Angeles District, as of September 2013.

571 Page 79 in Lichvar and Wakeley, 2004.
Clean Water Rule Response to Comments – Topic 8: Tributaries

533

(i.e., at the scale of small, truly headwater tributaries). Moreover, in these uncertain arid 

systems, there should be greater reliance on empirical data rather than surrogate 

indicators for the assertion of jurisdiction. Arid landscapes are not formed by processes 

similar to humid landscapes and should not be regulated as if they were. (Doc. #14135.1, 

p. 9-10)

Agency Response: See the summary responses for Sections 8.4 and 8.1.2. 

Scientists at the U.S. Army Corps of Engineers, Engineer Research and 

Development Center perform research aimed at improving OHWM delineation 

practices across the country. Two regional OHWM delineation manuals and a 

number of supporting research and technical reports have been developed to date. 

In addition, see the TSD section 7.A.

The Mosiac Company (Doc. #14640)

8.413 An additional discrepancy in the proposed rule exists in distinguishing ephemeral and 

intermittent tributaries (which are jurisdictional under the proposed rule) from gullies, 

rills, and non-wetland swales (spelled out as non-jurisdictional under the proposed rule). 

Both gullies and rills are defined in the proposed rule as erosional features that typically 

only carry water during precipitation events (79 Fed. Reg. at 22,218-22,219). They are 

typically deeper than they are wide, with very steep banks, formed by longitudinal 

(incising) erosional forces and lack an ordinary high water mark (OHWM) (79 Red. Reg. 

at 22,218). Additionally, wetland swales are defined as shallow, non-channelized troughlike depressions that carry water mainly during rainstorms or snowmelt (79 Fed. Reg. at 

22,219). In contrast, streams (this term is presumably used interchangeably with 

tributary) are characterized by the presence of bed and banks and an OHWM (Fed. Reg. 

at 22,219). Small, intermittent, and ephemeral conveyances are similar to gullies , rills, 

and non-wetland swales in that they also only carry water following rain events or 

snowmelt. The only difference between them, according to the agencies' definitions of 

each, is the presence of a bed, bank, and OHWM, which is largely a function of the 

geography, topography, and soil composition where they are located. However, proposed 

rule makes a categorical distinction that water features with a bed, bank, and OHWM are 

jurisdictional, and those without are not. No scientific literature or justification is 

provided for why the presence of a bed, bank, and OHWM determines that a given water 

feature meets the significant nexus standard for jurisdiction and affects the chemical, 

physical, and biological integrity of traditional navigable waters., rills, and non-wetland 

swales have been excluded from jurisdiction based on longstanding practice by the 

agencies (79 Fed. Reg. at 22,218) . In determining that these features are not waters of the 

U.S., the agencies previously have referenced the Riverside Bayview and the plurality 

Rapanos Supreme Court decisions wherein the Court gave deference to the agencies 

given the difficulty in determining where waters end, and acknowledged that certain 

features were not the focus of the CWA (79 Fed. Reg. at 22,218). Given that the agencies 

have long held that gullies, rills, and non-wetland swales are categorically nonjurisdictional, and small, intermittent, and ephemeral systems are functionally identical 

(differing only in the presence of a bed, bank, and OHWM according to the proposed 

rule), there is no scientific or legal basis to assert that small, intermittent, and ephemeral 

conveyances should be jurisdictional by rule. (p. 21-22)
Clean Water Rule Response to Comments – Topic 8: Tributaries

534

Agency Response: See summary response for “Relevance of Flow Regime” in 

section 8.1.1 of this RTC, particularly subsections on jurisdiction over intermittent 

and ephemeral waters and the legality of asserting jurisdiction over ephemeral 

waters. The agencies’ position in regard to tributaries is rooted in a science-based 

conclusion that such waters have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion. Section I of the Technical Support Document 

discusses the legal basis of the final rule, including consistency with the statute and 

Supreme Court decisions. 

National Mining Association (Doc. #15059)

8.414 To the extent the Agencies move forward with the current proposal, they must adopt the 

following changes in any final rule:

... 6) The Agencies should revise their approach to ephemeral waters by:

a. Clarifying in the regulatory text, preamble, and appendices that if an ephemeral water 

does not meet the full definition of “tributary” contained in the rule, it is excluded from 

CWA jurisdiction and cannot be brought in as jurisdictional under an “adjacency,” “other 

waters” or any other determination.

b. Should the Agencies continue to categorically assert jurisdiction over all ephemeral 

channels meeting the definition of “tributary” – which as discussed below NMA believes 

is not supported by the science – the Agencies should require that an ephemeral channel 

have a bed, bank, and all three primary ordinary high water mark (OHWM) indicators 

from the Corps’ August 2014 guidance,572 in addition to contributing flow to an (a)(1) 

through (a)(4) water, to be considered a tributary. Additionally, the Agencies should 

require that all three indicators be continuous from the confluence of the ephemeral 

channel and intermittent or perennial channel up to its delineated upstream boundary –

where all three indicators are no longer perceptible upstream, jurisdiction must end.

c. Developing criteria for arid regions - including empirical data evidencing flow 

(magnitude, duration, and frequency to traditional navigable waters), distance from 

traditionally navigable waters, etc. – that could be used as possible additional 

considerations in distinguishing between ephemeral channels and erosional features in 

such regions.

... (p. 3, 5-6)

Agency Response: Paragraph (b) of the final rule clearly states that all excluded 

features outlined therein, including most ditches and all erosional features such as 

gullies, rills and non-wetland swales, that do not meet the definition of “tributary,” 

are not jurisdictional waters of the United States, even where they otherwise meet 

the terms of paragraph (a), which defines “waters of the United States.” The 

definition of “tributary” in the final rule requires that flow must be of sufficient 

 

572 Mersel K. Matthew, et al., August 2014, “A Guide to Ordinary High Water Mark Delineation for Non-Perennial 

Streams in the Western Mountains, Valleys, and Coastal Region of the United States.”
Clean Water Rule Response to Comments – Topic 8: Tributaries

535

volume, frequency, and duration to create the physical characteristics of bed and 

banks and an ordinary high water mark. As described in Section IV(F) of the 

preamble to the final rule, the upper limit of a tributary is the point where a bed 

and banks and another indicator of OHWM cease to be identifiable. See the 

summary response for Section 8.4. Scientists at the U.S. Army Corps of Engineers, 

Engineer Research and Development Center have been performing research aimed 

at improving OHWM delineation practices across the country for over a decade. 

Two regional OHWM delineation manuals and a number of supporting research 

and technical reports have been developed to date.

8.415 III.Tributaries and Erosional Features.

In the preamble to the proposed rule, the Agencies recognize the difficulty in 

distinguishing between non-jurisdictional ephemeral features (gullies, rills, non-wetland 

swales) and ephemeral tributaries that are per se jurisdictional.58 Likewise, a recent 

guidance document issued by the U.S. Army Engineer Research and Development Center 

(ERDC) declares that “ordinary high water mark (OHWM) delineation in non-perennial 

(i.e., intermittent and ephemeral) streams can be especially challenging.”59 NMA 

members are well aware of these difficulties and share the widespread concern over the 

Agencies’ assertion of jurisdiction over all ephemeral tributaries. NMA provides the 

following in response to the Agencies’ request for comments on how they might provide 

additional clarity concerning how to distinguish between erosional features and 

tributaries:

A. Ephemeral Waters that are Not Tributaries Should be Expressly Excluded from 

Jurisdiction

In recent weeks, the Agencies have indicated that if an ephemeral water does not meet the 

definition for “tributary” contained in the rule, it is excluded from CWA jurisdiction. In 

other words, if the channel (defined by a bed, banks and OHWM) of an ephemeral 

drainage does not physically connect to a tributary system and contribute flow to an 

(a)(1) through (a)(4) water, it is not a tributary, and it cannot be brought in as 

jurisdictional under an “adjacency” or “other waters/significant nexus” determination.

While NMA supports this position, the regulatory text does not make this point clearly, 

and there are several statements in the preamble that appear to directly contradict it. The 

Agencies should add a sentence to the definition of “tributary” that unambiguously states 

that ephemeral waters that do not meet the definition of “tributary” are not “waters of the 

United States” under either the “adjacent” or “other waters” provisions. Additionally, the 

Agencies must revise several sections of the preamble and appendices to reflect their 

intent and avoid confusion. The highlighted language in the paragraphs below needs to be 

clarified to explicitly state that ephemeral waters not meeting the definition of “tributary” 

cannot be jurisdictional under other sections of the proposed rule, including those 

pertaining to “adjacency” and “other waters” :

P. 22204 (emphasis added) –

Waters that do not contribute flow, either directly or through another water, to a 

water identified in paragraphs (a)(1) through (4) of the proposed regulation are 

not considered jurisdictional as tributaries under the CWA. However, even if 
Clean Water Rule Response to Comments – Topic 8: Tributaries

536

such waters are not ‘‘tributaries,’’ they may be jurisdictional under other 

paragraphs of the proposed rule.

Pgs. 22,211 and 22,212 (emphasis added) –

Of additional concern was that the existing descriptive list of types of ‘‘other 

waters’’ includes some waters that would be jurisdictional under one of the 

proposed categories of ‘‘waters of the United States’’ that would be jurisdictional 

by rule, such as tributary streams. The agencies want to avoid questions of 

whether an intermittent stream that meets the definition of tributary also needs a 

separate significant nexus analysis. Under the proposed rule, that tributary stream 

does not require the significant nexus analysis. Removing the list of water types 

does not imply that any of the waters listed in the existing regulation are never 

jurisdictional under the proposed rule. When one of the waters on the current 

enumerated list does not fall under a proposed category for jurisdiction (for 

example, adjacent waters under (a)(6) or tributaries under (a)(5)), those 

waters would be jurisdictional if found to have a significant nexus under 

proposed paragraph (a)(7) on a case- specific basis.

Appendix A (emphasis added) –

Where waters are not considered tributaries (e.g. waters in a solely intrastate 

closed basin that does not contain a traditional navigable water, interstate water, 

or a territorial sea, or a connection thereto) or where waters, including wetlands, 

do not meet the proposed regulatory definition of adjacent, they should be 

evaluated to determine whether they are (a)(7) waters.

B. Additional Language is Needed to More Clearly Differentiate Between 

Jurisdictional Ephemeral Tributaries and Non-Jurisdictional Ephemeral Features

In addition to clarifying that ephemeral features not meeting the definition of “tributary” 

are not jurisdictional under the rule, the Agencies should also include additional 

considerations for distinguishing between ephemeral tributary streams and nonjurisdictional ephemeral features. Specifically, in light of the admitted difficulties in 

differentiating between tributaries and, for example, gullies and rills, NMA recommends 

that the Agencies require the presence of a bed, bank, and all three primary indicators 

from the 2014 Corps OHWM Guidance.573 In addition, we recommend that these 

indicators must be continuous from the confluence of the ephemeral tributary and 

intermittent or perennial channel up to its delineated upstream boundary to assert federal 

jurisdiction over an ephemeral stream. In other words, where the three indicators are no 

longer perceptible upstream, jurisdiction must end. Furthermore, because OHWM is not 

an appropriate indicator of flow in certain arid regions, NMA recommends that the 

Agencies establish some level of flow-based metrics, including magnitude, duration and 

frequency of flow to traditional navigable waters, for use as possible additional 

 

573 Mersel K. Matthew, et al., August 2014, “A Guide to Ordinary High Water Mark Delineation for Non-Perennial 

Streams in the Western Mountains, Valleys, and Coastal Region of the United States.”
Clean Water Rule Response to Comments – Topic 8: Tributaries

537

considerations in distinguishing between ephemeral channels and erosional features that 

could more clearly guide regulatory determinations in such regions.574

Pursuant to the Agencies’ express request for comment on this issue, this approach would 

help ensure that gullies, rills, and non-wetland swales are excluded from inappropriate 

jurisdictional designations as contemplated by the proposed rule. However, as discussed 

in detail in WAC’s comments, there is not a sound scientific basis for establishing the 

requisite “significant nexus” to assert jurisdiction over all ephemeral features with a bed, 

bank, and OHWM that contribute flow to an (a)(1) through (a)(4) water, even where the 

three primary OHWM indicators are continuously present. NMA’s recommendations in 

this section should not be interpreted as endorsing the Agencies’ contentions in this 

regard, but rather address the specific question of how to better differentiate between 

ephemeral drainages and rills, gullies and non-wetland swales should the Agencies 

nevertheless categorically assert jurisdiction over all ephemeral channels that meet the 

definition of “tributary.”

As described in more detail in the attached comments from GEI Consultants, one of the 

primary indicators of an ephemeral channel, along with a bed and banks, is the presence 

of an OHWM. As explained in the Corps Regulatory Guidance Letter (RGL) 05-05, the 

OHWM is determined by identifying those physical characteristics that correspond to the 

line on the shore established by fluctuations of water.575 The Corps itself admits, 

however, that OHWM determinations are complex and difficult with respect to perennial 

channels, and are even more challenging in the context of inherently unstable ephemeral 

channels, as OHWM indicators rely on a certain amount of geomorphic stability. As 

such, a rigorous set of criteria is needed to provide consistency in such determinations 

where, as is the case in the proposed rule, such determinations are central to establishing 

federal CWA jurisdiction.

To help minimize subjectivity in making OHWM determinations in the context of 

ephemeral channels, and thus increase the clarity and regulatory certainty that the rule 

aims to provide, all three primary OHWM indicators proposed by the Corps – namely, 1) 

a break in slope; 2) a change in bed sediment; and 3) vegetation patterns – must be 

present in a continuous fashion from the confluence of the ephemeral and seasonally 

inundated channels back up to the ephemeral channel’s upstream boundary. Without the 

presence of these continuous, perceptible indicators, it is unclear how the Agencies would 

distinguish between the most dynamic and episodic landscape features, including gullies 

and rills, and actual tributaries with an established landscape position and flow pattern. 

Additionally, as compared to current regulatory practice,576 if, as suggested in the August 

2014 OHWM Guidance, only one – or even no – primary indicator is required to 

establish an OHWM, jurisdiction would drastically expand, which the Agencies 

repeatedly state is not the intent of the rule. Furthermore, in certain arid regions with 

highly erodible soils and naturally sparse vegetation, even all three indicators can occur 

after a single storm event. Additional criteria in such regions could therefore help 

 

574 NMA is not recommending the development of such metrics for non-arid regions.

575 See Regulatory Guidance Letter, 05-05, Ordinary High Water Mark Identification, December 7, 2005.

576 See RGL 05-05 at 3 (Corps clearly stating that, to the maximum extent practicable, more than one characteristic 

should be present).
Clean Water Rule Response to Comments – Topic 8: Tributaries

538

distinguish between erosional features and ephemeral tributaries, including empirical data 

evidencing flow (magnitude, duration, and frequency to traditional navigable waters), 

distance from traditionally navigable waters, etc.

Finally, NMA has substantial concerns with respect to the Corps’ development of the 

recent OHWM guidance documents outside the scope of the “waters of the United 

States” rulemaking process in light of the fact that the information contained in those 

documents will significantly impact the implementation of the final rule. Whether a 

tributary is a water of the United States under the proposed rule depends in large part on 

the presence of an OHWM. Likewise, under existing regulations, OHWM is used to place 

limits on the extent of jurisdiction.577 Understanding how an agency identifies an OHWM 

is therefore critical to understanding the extent of federal CWA jurisdiction.578

Inconsistent with past agency practice,579 the new policy was developed without any

public awareness and quietly posted on the Corps’ website. Such action is inconsistent 

 

577 See 33 C.F.R. 328.4.

578 See, e.g., RGL 05-05, issued pursuant to a Memorandum of Agreement between the Corps and EPA.

579 The Corps’ failure to provide the regulated public with any advance notice that the policies concerning how to 

determine OHWM were being updated is inconsistent with the Corps’ past revisions of similar technical documents 

associated with delineating the limits of CWA jurisdiction. See, e.g., U.S. Army Corps of Engineers Alaska District, 

Special Public Notice: Draft Alaska Regional Supplement to the 1987 Wetland Delineation Manual (Public Notice 

No. SPN 2005-10) (June 28, 2005); U.S. Army Corps of Engineers Alaska District, Special Public Notice: Final 

Version of the Alaska Regional Supplement to the 1987 Wetland Delineation Manual (Public Notice No. SPN-2006-

445-FINAL) (Oct. 26, 2007); U.S. Army Corps of Engineers Portland District, Special Public Notice: Field Testing 

the Arid West Supplement: Draft Arid West Regional Supplement to the 1987 Wetland Delineation Manual (Sept. 2, 

2005); U.S. Army Corps of Engineers Baltimore District, Special Public Notice: Publication and One-Year Trial 

Implementation Period of the Atlantic and Gulf Coastal Plain Interim Regional Supplement to the 1987 Wetland 

Delineation Manual (Public Notice No. 08-77) (Dec. 9, 2008); U.S. Army Corps of Engineers Philadelphia District, 

Special Public Notice: Final Atlantic and Golf Coastal Plain Regional Supplement to the 1987 Wetland Delineation 

Manual (Public Notice No. CENAP-OP-R) (Dec. 20, 2010); U.S. Army Corps of Engineers, Environmental 

Assessment and Finding of No Significant Impact for the Caribbean Regional Supplement to the 1987 Wetland 

Delineation Manual at 3 (Undated); U.S. Army Corps of Engineers Philadelphia District, Public Comments and 

Responses: Draft Interim Eastern Mountains and Piedmont Regional Supplement to the 1987 Corps of Engineers 

Wetland Delineation Manual at 1 (Undated); U.S. Army Corps of Engineers Philadelphia District, Special Public 

Notice: Final Eastern Mountains and Piedmont Regional Supplement to the 1987 Corps of Engineers Wetland 

Delineation Manual (Public Notice No. CENAP-OP-R) (May 4, 2012); U.S. Army Corps of Engineers Galveston 

District, Public Notice: Request for Public Input on Proposed Wetland Indicators and Data Collection Procedures 

for Draft Great Plains Regional Supplement to the 1987 Wetland Delineation Manual (Sept. 27, 2006); U.S. Army 

Corps of Engineers, Environmental Assessment and Finding of No Significant Impact for the Hawaii and Pacific 

Islands Regional Supplement to the 1987 Wetland and Delineation Manual at 4 (May 6, 2009); U.S. Army Corps of 

Engineers Louisville District, Public Notice: Draft Midwest Regional Supplement to the 1987 Wetland and 

Delineation Manual (Public Notice No. LRL-2007-785-asb) (June 26, 2007); U.S. Army Corps of Engineers, 

Environmental Assessment and Finding of No Significant Impact for the Northcentral and Northeast Regional 

Supplement to the 1987 Wetland and Delineation Manual at 3 (Undated); U.S. Army Corps of Engineers 

Philadelphia District, Public Notice: Announcement of Version 2.0 of the Northcentral and Northeast Regional 

Supplement to the Corps of Engineers Delineation Manual (Public Notice No. CENAP-OP-R) (Feb. 14, 2012); U.S. 

Army Corps of Engineers Omaha District, Special Public Notice: Notice of Availability and Request for Public 

Comments: Draft Western Mountains & Valleys Regional Supplement to the 1987 Wetland Delineation Manual

(Apr. 20, 2007).
Clean Water Rule Response to Comments – Topic 8: Tributaries

539

with the concepts of due process and transparency in rulemaking.580 To remedy this 

problem, the Agencies must, prior to the promulgation of a final rule, officially notice the 

revised OHWM criteria as part of the current rule-making proceedings and provide the 

public with the opportunity to comment on them and understand their potential 

implications with respect to the scope of CWA jurisdiction. (p. 26-30)

Agency Response: Paragraph (b) of the final rule clearly states that all excluded 

features outlined therein, including most ditches and all erosional features such as 

gullies, rills and non-wetland swales that do not meet the definition of “tributary,” 

are not jurisdictional waters of the United States, even where they otherwise meet 

the terms of paragraph (a), which defines “waters of the United States.” The 

definition of “adjacent waters” has been revised and clarified in the final rule, and 

specific limitations have also been placed on the evaluation of “case specific” waters. 

See sections IV(G) and IV(H) of the preamble, respectively. As described in Section 

IV(F) of the preamble to the final rule, the upper limit of a tributary is the point 

where a bed and banks and another indicator of OHWM cease to be identifiable. 

See the summary response for Section 8.4. The term “ordinary high water mark” 

has been defined in Corps regulations since 1986, and used by Corps Districts 

nationwide to determine the lateral limits of jurisdiction over non-tidal water bodies 

for the CWA section 404 permitting program. Scientists at the Corps’ Engineer 

Research and Development Center have been performing research aimed at 

improving OHWM delineation practices across the country for over a decade. Two 

regional OHWM delineation manuals and a number of supporting research and 

technical reports have been developed to date. See summary response for 

“Relevance of Flow Regime” in section 8.1.1 of this RTC, particularly subsections 

on jurisdiction over intermittent and ephemeral waters and the legality of asserting 

jurisdiction over ephemeral waters. The agencies’ position in regard to tributaries 

is rooted in a science-based conclusion that such waters have a significant nexus 

either individually or in the aggregate with traditional navigable waters, interstate 

waters, and the territorial seas. Section VII of the Technical Support Document 

discusses the science supporting the agencies’ conclusion. Section I of the Technical 

Support Document discusses the legal basis of the final rule, including consistency 

with the statute and Supreme Court decisions.

Halliburton Energy Services, Inc. (Doc. #15509)

8.416 The proposed definition of tributary is an expansion of jurisdiction from current practice 

that has meaningful consequences. For example, in the arid west, under current 

application of the regulations most ephemeral drainages, ditches, and depressions do not 

require a jurisdictional determination at all - in practice, the Corps does not extend 

jurisdiction to these features. Perhaps the exclusions for gullies, swales and other 

erosional features will be appropriately expansive, but the rule and the preamble lack that 

clarity. For other features, photographic documentation of breaks in the OHWM of 

 

580 See Portland Cement Assoc. v. Ruckelshaus, 486 F. 2d 375, 385 (U.S. App. D.C. 1973)( “It is not consonant with 

the purpose of a rule-making proceeding to promulgate rules on the basis of inadequate data, or on data that, critical 

degree, is known only to the agency.”)
Clean Water Rule Response to Comments – Topic 8: Tributaries

540

drainages are regularly used to establish the limits of federal jurisdiction, limits that are 

currently recognized by the Corps. (p. 4)

Agency Response: Section I of the Technical Support Document, discusses the 

historic scope of the existing regulatory definition of waters of the United States.

See summary response for “Relevance of Flow Regime” in section 8.1.1 of this RTC, 

particularly subsections on jurisdiction over intermittent and ephemeral waters and 

the legality of asserting jurisdiction over ephemeral waters. The exclusions in 

paragraph (b) of the final rule have been revised to clearly exclude most ditches and 

all erosional features such as gullies, rills and non-wetland swales that do not meet 

the definition of “tributary,” from consideration as waters of the United States.

Alpha Natural Resources, Inc. (Doc. #15624)

8.417 V. THE AGENCIES SHOULD PROVIDE A CLEAR METHODOLOGY TO 

DIFFERENTIATE TRIBUTARIES FROM NON-JURISDICTIONAL 

EROSIONAL FEATURES IN APPALACHIA

The preamble to the proposed rule acknowledges the practical difficulties of 

distinguishing jurisdictional ephemeral tributaries581 from non-jurisdictional erosional 

features such as gullies. See 79 Fed. Reg. 22,218-19. Currently, Corps’ personnel 

throughout Appalachia exhibit internal inconsistently when determining whether features 

are either jurisdictional streams or non-jurisdictional gullies. This lack of consistency 

places a considerable burden on Alpha and others seeking jurisdictional determinations in 

the region. Accordingly, the agencies should clarify that features that fail to satisfy all of 

the elements of a “tributary” are not per se jurisdictional.

The proposed rule defines a “tributary” as a water that 1) has a bed and banks and an 

ordinary high water mark; and 2) contributes flow, either directly or through another 

water, to downstream navigable waters. 79 Fed. Reg. 22,263. To help the Corps’ field 

inspectors in Appalachia more accurately and consistently distinguish between 

jurisdictional “tributaries” from non-jurisdictional features, Alpha encourages the 

agencies to expand the list of criteria that must be present for a feature to qualify as a 

“tributary.”

While a “tributary” must “contribute flow,” the mere presence or absence of a bed and 

banks and an ordinary high water mark, without more, is often insufficient to allow 

headwater tributaries to be differentiated from non-jurisdictional erosional features. 

Alpha encourages the agencies to require additional indications of regular flow to be 

present in order for a feature to be deemed a “tributary.” For example, features within 

which vegetation is growing or plant litter from previous years is still present and 

undisturbed do not “contribute flow” to downstream waters in sufficient quantities or 

with sufficient regularity to warrant federal regulation.

 

581 Alpha supports the position of the Waters Advocacy Coalition that the agencies lack a sound scientific basis for 

their determination that any ephemeral feature satisfying the proposed definition of a “tributary” has a per se 

“significant nexus” to traditional navigable waters. Alpha’s comments regarding how the agencies can better 

differentiate erosional features from ephemeral tributaries is not an endorsement of the agencies’ position that all 

ephemeral tributaries are per se jurisdictional.
Clean Water Rule Response to Comments – Topic 8: Tributaries

541

A water feature’s substrate can also provide insight into whether it is a tributary or a nonjurisdictional erosional feature. As the preamble explains, “time has shaped streams into 

geographic features distinct from gullies and rills.” 79 Fed. Reg. 22,263. For this reason, 

Appalachian streams that regularly carry flow and have been doing so for many years 

typically contain substrate consisting of sand, fine gravel, or cobble, while recentlycreated erosional features have substrates of exposed soil. Similarly, tributaries that were 

established naturally over time follow the natural topography of the land while erosional 

features are more recently formed, often as a byproduct of an identifiable disturbance to 

the landscape.

Finally, the agencies should clarify that even when a water feature possesses the 

necessary attributes of a jurisdictional tributary, this “tributary” classification terminates 

at the point upstream where those necessary features are no longer clearly definable. (p. 

12-14)

Agency Response: The definition of “tributary” in the final rule requires that flow 

must be of sufficient volume, frequency, and duration to create the physical 

characteristics of bed and banks and an ordinary high water mark. If a water lacks 

sufficient flow to create such characteristics, it is not considered “tributary” under 

this rule. The agencies believe that erosional features lack sufficient volume, 

frequency, and duration of flow to create the physical characteristics of bed and 

banks and an ordinary high water mark. See the summary response for Section 8.4, 

particularly the sub-section titled, “Distinction between an ephemeral water and a 

non-jurisdictional gulley, rill or non-wetland swale.” As described in Section IV(F) 

of the preamble to the final rule, the upper limit of a tributary is the point where a 

bed and banks and another indicator of OHWM cease to be identifiable. As the 

commenter highlights, substrate type is used in the identification of OHWM, 

however it is primarily evaluated by comparing it to the banks and surrounding 

soil.

Dominion Resources Services, Inc. (Doc. #16338)

8.418 ...To the extent the agencies move forward with the proposal, we make the following 

recommendations:

...

 The proposed rule explicitly exempts “gullies and rills” while considering 

ephemeral tributaries as jurisdictional. The preamble recognizes the difficulty in 

distinguishing between these two categories of features in the field. To the extent 

that the rule considers ephemeral features WOTUS, we request the rule and 

preamble clearly establish how these features will be differentiated. (p. 7-8)

...

Agency Response: The definition of “tributary” in the final rule requires that flow 

must be of sufficient volume, frequency, and duration to create the physical 

characteristics of bed and banks and an ordinary high water mark. If a water lacks 

sufficient flow to create such characteristics, it is not considered “tributary” under 

this rule. The agencies believe that erosional features lack sufficient volume, 
Clean Water Rule Response to Comments – Topic 8: Tributaries

542

frequency, and duration of flow to create the physical characteristics of bed and 

banks and an ordinary high water mark. See the summary response for Section 8.4, 

particularly the sub-section titled, “Distinction between an ephemeral water and a 

non-jurisdictional gulley, rill or non-wetland swale.” 

Alameda County Cattlewomen (Doc. #8674)

8.419 It is also necessary for the agency to articulate their definition of "ditches," and provide a 

clear indication of the difference between a ditch and a gully. The agencies exclude 

gullies, but there are many features on the landscape where it is unclear whether the 

feature will be a regulated ditch, or an unregulated gully." The agencies explanation in 

the preamble regarding gullies is inadequate for landowners to adequately distinguish 

them from regulated tributaries." The agencies' explanation says that gullies are younger 

than streams and lack an OHWM. First, how do agencies’ propose that a landowner will 

know the age of the stream/gully and at what age does the gully become a stream? (p. 11)

Agency Response: See the summary response for section 6.2, “Excluded Ditches” 

in this RTC for a discussion of how the proposed exclusions for ditches were edited 

and clarified for the final rule. The definition of “tributary” in the final rule 

requires that flow must be of sufficient volume, frequency, and duration to create 

the physical characteristics of bed and banks and an ordinary high water mark. If a 

water lacks sufficient flow to create such characteristics, it is not considered 

“tributary” under this rule. The agencies believe that erosional features lack 

sufficient volume, frequency, and duration of flow to create the physical 

characteristics of bed and banks and an ordinary high water mark.

Montana Farm Bureau Federation (Doc. #12715)

8.420 ...what qualifies as an "erosional feature." The Agencies claim erosional features will be 

non-jurisdictional, unlike jurisdictional ephemeral tributaries. Unfortunately, this rule 

does not provide a way for farmers, ranchers, or anyone else really, a way to determine 

the difference. Without clarity, farmers and ranchers are forced to either A) assume that 

any ephemeral drainage that carries any amount of water, no matter how much, how 

little, or for any period of time would be considered a jurisdictional "tributary," not as an 

erosional feature, which common sense would lead one to formerly believe, B) ask the 

Corps for a jurisdictional determination on what could be countless low spots, which 

could be a time consuming and tedious process, or C) take a chance that any of the 

regular day to day farming and ranching practices that must be carried out on or near 

these locations could lead to an "unlawful" discharge carrying penalties much too great to 

be absorbed by any farm or ranch. Farmers and ranchers consider water quality to be a 

very important part of their operations and desire to do the right thing in all situations. 

They simply deserve clarity and ability to carry out their farming and ranching practices 

in order to grow food for the world. They should not be forced to treat land as water. (p. 

3)

Agency Response: Erosional features are described in section IV(I) of the 

preamble. Also see the summary response for Section 8.4, particularly the subsection titled, “Distinction between an ephemeral water and a non-jurisdictional 

gulley, rill or non-wetland swale.” The definition of “tributary” in the final rule 
Clean Water Rule Response to Comments – Topic 8: Tributaries

543

requires that flow must be of sufficient volume, frequency, and duration to create 

the physical characteristics of bed and banks and an ordinary high water mark. If a 

water lacks sufficient flow to create such characteristics, it is not considered 

“tributary” under this rule. The agencies believe that erosional features lack 

sufficient volume, frequency, and duration of flow to create the physical 

characteristics of bed and banks and an ordinary high water mark. By grounding 

the definition of “tributary” in the final rule to the above referenced specific 

physical features, the agencies believe that confusion regarding whether a feature is 

a “tributary” or a non-jurisdictional “erosional feature” will be minimal. In 

addition, all statutory exemptions in the CWA, including those exempting normal 

farming, silviculture and ranching activities from the need to obtain authorizations 

under CWA section 404, remain in effect and unchanged by the final rule.

8.421 4. If the Agencies persist in promulgating a rule that allows jurisdiction over ephemeral 

waterways, the Agencies must distinguish between ephemeral waterways and erosional 

features and clarify when ephemeral waterways are jurisdictional. 

a. The Proposed Rule should state that ephemeral waters are fed in part by a natural 

groundwater source, whereas erosional features are fed solely by surface run-off. 

b. The Proposed Rule should clarify thatt hat no erosional features will be regulated. 

c. The Proposed Rule should clarify that ephemeral waters are only jurisdictional 

while they contribute flow to Section (a)(l) through (a)(4) waters, meaning the 

bed and banks of a dry ephemeral waterway would not be regulated. (p. 8)

Agency Response: The final rule asserts that ephemeral features meeting the 

definition of “tributary” are jurisdictional. The definition of “tributary” does in 

fact require that the water “contributes flow, either directly or through another 

water (including an impoundment identified in paragraph (a)(4)...), to a water 

identified in paragraphs (a)(1) through (3)....” In contrast, all ephemeral erosional 

features not meeting the definition of “tributary” are not waters of the United 

States, as indicated in paragraph (b) of the final rule. Longstanding agency practice 

defines ephemeral streams as those that have flowing water only in response to 

precipitation events in a typical year, and are always above the water table.

North American Meat Association and American Meat Institute (Doc. #13071)

8.422 ...[T]he preamble discusses the challenge attendant to distinguishing between tributaries 

and erosional features, such as gullies, which are categorically excluded from 

jurisdiction.582 Both erosional features and ephemeral drainages are small features that 

typically only carry water during precipitation events, raising questions about how 

regulators will distinguish between ephemeral drainages and gullies or rills, resulting in 

arbitrary and inconsistent decision-making. (p. 6-7)

Agency Response: The definition of “tributary” in the final rule requires that flow 

must be of sufficient volume, frequency, and duration to create the physical 

characteristics of bed and banks and an ordinary high water mark. If a water lacks 

 

582 79 Fed. Reg. at 22,218.
Clean Water Rule Response to Comments – Topic 8: Tributaries

544

sufficient flow to create such characteristics, it is not considered “tributary” under 

this rule. The agencies believe that erosional features lack sufficient volume, 

frequency, and duration of flow to create the physical characteristics of bed and 

banks and an ordinary high water mark. See the summary response for Section 8.4, 

particularly the sub-section titled, “Distinction between an ephemeral water and a 

non-jurisdictional gulley, rill or non-wetland swale.” 

Kennewick Irrigation District, Kennewick, Washington (Doc. #13571)

8.423 A clear definition needs to be included in the final version of the rule for "gullies", "rills", 

and "non-wetland swales." The rule should recognize that in irrigated lands, features that 

could be considered to be "gullies", "rills" and "non-wetland swales" were once formerly 

dry in a natural state, but now commonly convey irrigation water due to operational spills 

and seepage. The rule should then continue to clearly exempt these features. (p. 5)

Agency Response: The definition of “tributary” in the final rule requires that flow 

must be of sufficient volume, frequency, and duration to create the physical 

characteristics of bed and banks and an ordinary high water mark. If a water lacks 

sufficient flow to create such characteristics, it is not considered “tributary” under 

this rule. The agencies believe that erosional features lack sufficient volume, 

frequency, and duration of flow to create the physical characteristics of bed and

banks and an ordinary high water mark. See the summary response for Section 8.4, 

particularly the sub-section titled, “Distinction between an ephemeral water and a 

non-jurisdictional gulley, rill or non-wetland swale.” In addition, see the summary 

response for section 6.2, “Excluded Ditches” in this RTC for a discussion of how the 

proposed exclusions for ditches were edited and clarified for the final rule.

Kansas Agriculture Alliance (Doc. #14424)

8.424 Tributaries Cannot be Categorically Included in WOTUS

...

With this illegal and all-encompassing definition of tributary, Kansas farmers, ranchers, 

and agricultural service providers will be forced to obtain section 404 and 402 CWA 

permits to conduct ordinary farm activities like applying fertilizers and pesticides or 

constructing and maintaining farm ponds. As written any erosional feature in a field or 

pasture that has a bed, bank, and ordinary high water mark (OHWM) (i.e. “clear, natural 

line impressed on the bank, shelving, changes in the character of soil, destruction of 

terrestrial vegetation, the presence of litter and debris, or other appropriate means”)583

means a farmer or rancher could face a draconian civil penalty for ordinary farm 

activities. Whether or not this is the agencies “intent” is irrelevant given the plain 

language of the proposed rule, especially when considered with the citizen suit sections 

of the CWA.584 (p. 4)

 

583 33 C.F.R. § 328.3(e).

584 See 33 U.S.C. § 1365 (allowing a civil action by “any person”).
Clean Water Rule Response to Comments – Topic 8: Tributaries

545

Agency Response: The agencies disagree that tributaries cannot be categorically 

considered waters of the United States. The agencies’ position in regard to 

tributaries is rooted in a science-based conclusion that such waters have a 

significant nexus either individually or in the aggregate with traditional navigable 

waters, interstate waters, and the territorial seas. Section VII of the Technical 

Support Document discusses the science supporting the agencies’ conclusion. 

Section I of the Technical Support Document discusses the legal basis of the final 

rule, including consistency with the statute and Supreme Court decisions. The 

agencies believe that erosional features, such as gullies, rills and non-wetland swales, 

lack sufficient volume, frequency, and duration of flow to create the physical 

characteristics of bed and banks and an ordinary high water mark that are required 

under the definition of “tributary.” The final rule excludes most ditches and all 

erosional features such as gullies, rills and non-wetland swales that do not meet the 

definition of “tributary.” In addition, artificial lakes and ponds created in dry land 

and used primarily for such uses as stock watering, irrigation, etc. are also explicitly 

excluded. Finally, all statutory exemptions in the CWA, including those exempting 

normal farming, silviculture and ranching activities from the need to obtain 

authorizations under CWA section 404, remain in effect and unchanged by the final 

rule. 

Georgia Paper & Forest Products Association (Doc. #14924)

8.425 The impacts of the proposed rule that we specifically draw your attention to include the 

following.

...

5) Ditches, gullies, rills, and emphemeral streams should only be covered by the rule as 

jurisdictional waters if they also meet the definition of wetlands, as discussed above, i.e. 

they meet all three of the wetlands criteria in the 1987 USACE guidelines. (p. 2, 3)

Agency Response: The agencies disagree. Gullies and rills are in fact explicitly 

excluded from consideration as waters of the United States in the final rule. 

Paragraph (b) of the rule also explicitly excludes most ditches that are not relocated 

tributaries or excavated in tributaries. In contrast, ephemeral streams meeting the 

definition of “tributary” are waters of the United States. See summary response for 

“Relevance of Flow Regime” in section 8.1.1 of this RTC, particularly subsections 

on jurisdiction over intermittent and ephemeral waters and the legality of asserting 

jurisdiction over ephemeral waters. The agencies’ position in regard to tributaries 

is rooted in a science-based conclusion that such waters have a significant nexus 

either individually or in the aggregate with traditional navigable waters, interstate 

waters, and the territorial seas. Section VII of the Technical Support Document 

discusses the science supporting the agencies’ conclusion.

North Carolina Farm Bureau Federation (Doc. #15078)

8.426 The proposed rule fails to provide a meaningful way to distinguish "erosional features," 

which the Agencies claim will be non-jurisdictional, from jurisdictional ephemeral 

tributaries. The Agencies explain:
Clean Water Rule Response to Comments – Topic 8: Tributaries

546

Rills are less permanent on the landscape than streams and typically lack an 

OHWM, whereas gullies are younger than streams in geologic age and also 

typically lack an OHWM; time has shaped streams into geographic features 

distinct from gullies and rills. The two main processes that result in the formation 

of gullies are downcutting and headcutting, which are forms of longitudinal 

(incising) erosion. These actions ordinarily result in erosional cuts that are often 

deeper than they are wide, with very steep banks, often small beds, and typically 

only carry water during precipitation events. The principal erosional processes 

that modify streams are also downcutting and headcutting. In streams, however, 

lateral erosion is also very important. The result is that streams, except on steep 

slopes or where soils are highly erodible, are characterized by the presence of bed 

and banks and an OHWM as compared to typical erosional features that are more 

deeply incised.

(79 Fed. Reg. at 22,218-19 (citations omitted)). Explanations such as this are worse than 

unhelpful to the regulated public, whose land features will be deemed to be "tributaries" 

or "erosional features" based on the discretion and subjective judgment of the Agencies' 

staff. The proposal requests comment on how the Agencies could provide "greater 

clarity" on how to distinguish erosional features from ephemeral tributaries and requests 

comment on how to distinguish swales from ephemeral tributaries If the rule is revised, 

the way to provide more clarity in this case is to state that no ephemeral streams, 

ephemeral features or ephemeral waters of any kind are ''waters of the US", 

thereby eliminating the need to distinguish erosional features and swales from 

ephemeral tributaries. (p. 7-8)

Agency Response: The agencies disagree that ephemeral streams, waters and 

features should be categorically excluded from waters of the United States. The 

agencies’ position in regard to tributaries is rooted in a science-based conclusion 

that such waters have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

conclusion. The agencies believe that erosional features, such as gullies, rills and 

non-wetland swales, lack sufficient volume, frequency, and duration of flow to 

create the physical characteristics of bed and banks and an ordinary high water 

mark, which are required under the definition of “tributary.” The final rule 

excludes most ditches and all erosional features such as gullies, rills and nonwetland swales that do not meet the definition of “tributary.” See the summary 

response for Section 8.4, particularly the sub-section titled, “Distinction between an 

ephemeral water and a non-jurisdictional gulley, rill or non-wetland swale.” 

Missouri Farm Bureau Federation (Doc. #15224)

8.427 ...the proposed rule fails to provide a meaningful way to distinguish “erosional features,” 

which the Agencies claim will be non-jurisdictional, from jurisdictional ephemeral 

tributaries. As a result, farmers will be forced to either (1) presume that an ephemeral 

drainage that carries water only when it rains is a jurisdictional tributary, or (2) seek a 

jurisdictional determination from the Corps, or (3) take a chance that their activities near 
Clean Water Rule Response to Comments – Topic 8: Tributaries

547

or in such features may result in unlawful discharges carrying civil penalties of up to 

$37,500 a day. This is not clarity. (p. 3)

Agency Response: The agencies believe that erosional features, such as gullies, 

rills and non-wetland swales, lack sufficient volume, frequency, and duration of flow 

to create the physical characteristics of bed and banks and an ordinary high water 

mark that are required under the definition of “tributary.” The final rule excludes 

most ditches and all erosional features such as gullies, rills and non-wetland swales 

that do not meet the definition of “tributary.” Finally, all statutory exemptions in 

the CWA, including those exempting normal farming, silviculture and ranching 

activities from the need to obtain authorizations under CWA section 404, remain in 

effect and unchanged by the final rule

National Alliance of Forest Owners (Doc. #15247)

8.428 B. The Agencies Should Expand the Exclusions for Erosional Features to Cover 

Ephemeral Drainages.

The proposed rule categorically excludes several erosional features (gullies, rills, and 

non-wetland swales) from the definition of “waters of United States,”585 and NAFO 

agrees that these features should remain non-jurisdictional. The Agencies should extend 

the exclusion to cover ephemeral drainages on the same grounds. Even the Agencies 

seem to acknowledge the similarities between these features and the difficulty in 

distinguishing between excluded erosional features and jurisdictional tributaries. Yet, the 

Agencies are unable to articulate a meaningful justification for the differential treatment 

apart from noting the absence of an ordinary high water mark in the excluded features.586

But the ordinary high water mark concept has long befuddled regulators and is not a 

reliable basis for distinguishing between jurisdictional and non-jurisdictional features.587

In addition, the Agencies felt the need to clarify in the preamble that puddles are not 

jurisdictional waters, but the very same rationale for excluding puddles applies to 

ephemeral drainages.588 Specifically, the Agencies explained that puddles that “form[] on 

pavement or uplands immediately after a rainstorm, snow melt, or similar event . . . 

cannot reasonably be considered a water body or aquatic feature at all, because usually 

[they] exist[] for only a brief period of time before the water in the puddle[s] evaporates 

or sinks into the ground. Puddles of this sort obviously are not, and never have been 

thought to be, waters of the United States subject to CWA jurisdiction.”589 This rationale 

applies with equal force to ephemeral drainages, yet the Agencies categorically assert 

jurisdiction over them as tributaries.

If the Agencies decline to exclude ephemeral drainages from the definition of “waters of 

the United States,” they should at least include some sort of variance provision rather 

than categorically assert jurisdiction over all ephemeral drainages. Just because a 

 

585 79 Fed. Reg. at 22,263.

586 See id. at 22,218-19.

587 See supra Part II.A.

588 See 79 Fed. Reg. at 22,218.

589 Id.
Clean Water Rule Response to Comments – Topic 8: Tributaries

548

regulator is able to identify a bed, banks, and ordinary high water mark on ordinarily dry 

lands and determine that, when it rains, there will be some minimal contribution of flow 

to a jurisdictional water does not mean there is a significant nexus to that jurisdictional 

water to support CWA jurisdiction over the ephemeral feature. Not all headwaters are 

equal and thus, the categorical assertion of jurisdiction over all tributaries is 

unsupportable. (p. 23-24)

Agency Response: Puddles do not contribute flow either directly through another 

water to downstream traditional navigable waters, interstate waters or the 

territorial seas; thus firmly distinguishing puddles from ephemeral tributaries. The 

agencies’ position in regard to tributaries, including ephemeral tributaries, is rooted 

in a science-based conclusion that such waters have a significant nexus either 

individually or in the aggregate with traditional navigable waters, interstate waters, 

and the territorial seas. Section VII of the Technical Support Document discusses 

the science supporting the agencies’ conclusion. The agencies believe that erosional 

features, such as gullies, rills and non-wetland swales, lack sufficient volume, 

frequency, and duration of flow to create the physical characteristics of bed and 

banks and an ordinary high water mark, which are required under the definition of 

“tributary.” See the summary response for Section 8.4, particularly the sub-section 

titled, “Distinction between an ephemeral water and a non-jurisdictional gulley, rill 

or non-wetland swale.” See also summary response 6.0 on ditches. 

American Forest & Paper Association (Doc. #15420)

8.429 C. Proposed Exemption for Gullies, Rills, and Non-wetland Swales

The Proposal includes an exemption for “gullies and rills and non-wetland swales” 

((122.2)(b)(5)(vii)). The Proposal does not define “gully,” “rill,” or “swale,” but the 

Preamble talks in terms of lacking features such as an Ordinary High Water Mark 

(OHWM) and distinct bed and banks. See 79 Fed. Reg. at 22218-19. That explanation 

must be included in the regulation itself. It would be helpful as well if EPA provided a 

qualitative aspect to the definition: for example, that they are natural topographic features 

that may carry water at times. The agencies requested comment on how a gully or nonwetland swale is differentiated from an ephemeral stream (suggesting that the latter 

would not be exempt.). In addition to not having all of the necessary three characteristics 

of OHM, distinct bed, and defined banks, it may be appropriate to describe gullies and 

swales as being of limited length. Similarly, the agencies’ statement (79 Fed. Reg. at 

22219) that a gully or swale may, even if exempt, provide a hydrological connection 

between a wetland and a tributary of a navigable water, so as to make the wetland subject 

to CWA jurisdiction, should only apply if there is a relatively short distance between the 

wetland and the navigable water. Otherwise, the theoretical effect of the wetland on the 

navigable water through the gully or swale is too attenuated to form the basis for CWA 

jurisdiction. (p. 10)

Agency Response: The exclusions in paragraph (b) of the final rule have been 

revised and clarified. While the proposed rule excluded “gullies and rills and nonwetland swales,” the agencies intended that all erosional features would be excluded. 

Thus, the final rule states that “erosional features, including gullies, rills and other 

ephemeral features that do not meet the definition of tributary, non-wetland swales, 
Clean Water Rule Response to Comments – Topic 8: Tributaries

549

and lawfully constructed grassed waterways” are not waters of the United States. 

Section IV(I) of the preamble to the final rule does make clear, however, that 

“...while the waters listed in the exclusions [in paragraph (b)] are never ‘waters of

the United States,’ they can serve as a hydrologic connection that the agencies would 

consider under a case-specific significant nexus under paragraphs (a)(7) and (a)(8).”

Jensen Livestock and Land LLC (Doc. #15440)

8.430 ...the agency has failed in the first instance of providing the public with a clear 

description of a “ditch.” Considering that some ditches will be jurisdictional while 

“gullies” and “rills,” along with (b)(3) and (4) ditches are excluded, it is of utmost 

importance to have a clear indication of what the agencies would categorize a water 

feature as. At present, the proposed rule fails to provide such descriptions. The discussion 

of gullies and rills in the preamble is inadequate for a landowner to be capable of 

distinguishing the features. (p. 22-23)

Agency Response: See the summary response for section 6.2, “Excluded Ditches” 

in this RTC for a discussion of how the proposed exclusions for ditches were edited 

and clarified for the final rule. In addition, section IV(I) and section IV(F) of the 

preamble discuss non-jurisdictional ditches and jurisdictional ditches, respectively. 

The definition of “tributary” in the final rule requires that flow must be of sufficient 

volume, frequency, and duration to create the physical characteristics of bed and 

banks and an ordinary high water mark. If a water lacks sufficient flow to create 

such characteristics, it is not considered “tributary” under this rule. The agencies 

are aware that terms such as “gully” and “rill” may have different meanings 

throughout the country. Therefore, by grounding the definition of “tributary” in 

the final rule to the above referenced specific physical features, the agencies believe 

that confusion regarding whether a feature is a “tributary” or a non-jurisdictional 

“erosional feature” will be minimal. See the summary response for Section 8.4, 

particularly the sub-section titled, “Distinction between an ephemeral water and a 

non-jurisdictional gulley, rill or non-wetland swale.”

Iowa Farm Bureau Federation (Doc. #15633.1)

8.431 The rule provides no clarity of when a land feature is a “tributary” or when it is an 

excluded gully, rill or non-wetland swale. The rule’s preamble describes time and 

OHWM as the key factors for making the distinction, but provides no duration, frequency 

or magnitude component. It makes no distinction of when a flow path or channel ceases 

to be a tributary.590 The terms “gully, rill and non-wetland swale” were deliberately left 

undefined leaving landowners in the tenuous position of having to prove their property 

does not contain a tributary. Because the terms are left undefined in the wake of an 

expanded tributary definition, the effect of the rule is to significantly narrow the 

exclusion as a practical matter. (p. 5)

Agency Response: The definition of “tributary” in the final rule requires that flow 

must be of sufficient volume, frequency, and duration to create the physical 

 

590 69 Fed. Reg. 22218-19.
Clean Water Rule Response to Comments – Topic 8: Tributaries

550

characteristics of bed and banks and an ordinary high water mark. If a water lacks 

sufficient flow to create such characteristics, it is not considered “tributary” under 

this rule. The agencies are aware that terms such as “gully” and “rill” may have 

different meanings throughout the country. Therefore, by grounding the definition 

of “tributary” in the final rule to the above referenced specific physical features, the 

agencies believe that confusion regarding whether a feature is a “tributary” or a 

non-jurisdictional “erosional feature” will be minimal. As described in Section 

IV(F) of the preamble to the final rule, the upper limit of a tributary is the point 

where a bed and banks and another indicator of OHWM cease to be identifiable. 

See the summary response for Section 8.4, particularly the sub-section titled, 

“Distinction between an ephemeral water and a non-jurisdictional gulley, rill or 

non-wetland swale.”

Montana Stockgrowers Association (Doc. #16937)

8.432 In reviewing documentation by the Montana Department of Environmental Quality 

(DEQ), this uncertainty also exits between potential jurisdictional waters and erosional 

features. The DEQ, Guidelines on Erosional Features, states: Swale: -In cross section, a 

generally broad, shallow feature where run off may become concentrated. A thalweg and 

a floodplain are generally not discernable. A swale is specifically excluded as a 

WOTUS, but waters within a floodplain would be considered a WOTUS. If these two 

features are "generally not discernable," landowners will be faced with considerable 

uncertainty and face potential ramifications as they conduct their operations on a daily 

basis. In addition, this same document defines a gully as: Gully: -An erosional feature 

caused by concentrated but intermittent flow of water usually during and immediately

following large run off events. Once again, gully is exempted, but an intermittent stream 

is considered a WOTUS. Our organizations assert that only stream features with 

"relatively permanent, standing or continuous" flow, pursuant to Justice Scalia's plurality 

opinion in Rapanos should be included in the definition of "tributary." This would limit 

the number of features that can be considered "tributaries" to those that could actually 

have a significant impact on the water quality of downstream waters, pursuant to the 

decision in Rapanos. It would also provide needed clarity to the ranching community.

We assert that intermittent and ephemeral features should NOT be considered "waters of 

the U.S." because these features are best regulated by states and localities, and were not 

intended by Congress to be regulated by the federal government. We recommend the 

agencies should include in the exclusion, water features that have a bed and bank and in 

which water flows only briefly during and following a period of rainfall in the immediate 

locality. In addition, the term "tributary" to most landowners in Montana is going to be a 

flowing feature like a river, creek, or stream. Ponds and wetlands are not what most 

would consider a "tributary" and therefore we request the agencies to remove ponds, 

wetlands and any other non-flowing feature from inclusion in the definition of 

"tributary." (p. 7)

Agency Response: Non-wetland swales are not waters of the United States, 

regardless of where they are located on the landscape. The agencies’ interpretation 

of the scope of the CWA in the final rule is informed by the best available peerreviewed science, policy judgments and legal interpretations as to which waters have 
Clean Water Rule Response to Comments – Topic 8: Tributaries

551

a “significant nexus” with traditional navigable waters, interstate waters, and the 

territorial seas. The “significant nexus” standard articulated and refined in recent

Supreme Court opinions is the touchstone for the agencies’ interpretation of the 

CWA’s jurisdictional scope. The agencies disagree that intermittent and ephemeral 

tributaries should not be waters of the United States. The agencies’ position in 

regard to tributaries is rooted in a science-based conclusion that such waters have a 

significant nexus either individually or in the aggregate with traditional navigable 

waters, interstate waters, and the territorial seas. Section VII of the Technical 

Support Document discusses the science supporting the agencies’ conclusion. 

Section I of the Technical Support Document describes the consistency of the final 

rule with both the statute and judicial decisions, including those of the U.S. Supreme 

Court. See the summary responses in sections 8.1 and 8.2 above for discussions 

concerning the revised definition of “tributary” in the final rule, which now omits 

wetlands, lakes and ponds.

Greene County Farm Bureau (Doc. #17007)

8.433 We are also concerned that gullies, rills and non-wetland swales will be considered 

regulated features even though they are generally deemed to be exempt when they are 

within fields. Those exact same features have been regulated in construction projects, 

such as when roads are built or repaired. It is also our understanding that the agencies 

may still conduct on-site reviews of some gullies, rills, and non-wetland swales to 

determine whether they may be declared to actually be a tributary and not an exempt 

feature or to review the amount of flow they may carry. (p. 2)

Agency Response: Gullies, rills and other ephemeral features that do not meet the 

definition of “tributary” and non-wetland swales are explicitly excluded in 

paragraph (b) of the final rule. These features will not be waters of the United 

States.

Agribusiness Association of Kentucky et al. (Doc. #18005)

8.434 The proposed rule fails to provide a meaningful way to distinguish "erosional features," 

which the Agencies claim will be non-jurisdictional, from jurisdictional ephemeral 

tributaries. The Agencies explain:

Rills are less permanent on the landscape than streams and typically lack an 

OHWM, whereas gullies are younger than streams in geologic age and also 

typically lack an OHWM; time has shaped streams into geographic features 

distinct from gullies and rills.

The two main processes that result in the formation of gullies are downcutting and 

headcutting, which are forms of longitudinal (incising) erosion. These actions 

ordinarily result in erosional cuts that are often deeper than they are wide, with 

very steep banks, often small beds, and typically only carry water during 

precipitation events. The principal erosional processes that modify streams are 

also downcutting and headcutting. In streams, however, lateral erosion is also 

very important. The result is that streams, except on steep slopes or where soils 

are highly erodible, are characterized by the presence of bed and banks and an 

OHWM as compared to typical erosional features that are more deeply incised.
Clean Water Rule Response to Comments – Topic 8: Tributaries

552

79 Fed. Reg. at 22,218-19 (citations omitted). Explanations such as this are worse than 

unhelpful to the regulated public, whose land features will be deemed to be "tributaries" 

or "erosional features" based on the discretion and subjective judgment of Agency staff. 

The proposal requests comment on how the Agencies could provide "greater clarity" on 

how to distinguish erosional features from ephemeral tributaries. Id. at 22,219. We are 

left wondering how the Agencies could possibly provide less clarity. (p. 7)

Agency Response: The definition of “tributary” in the final rule requires that flow 

must be of sufficient volume, frequency, and duration to create the physical 

characteristics of bed and banks and an ordinary high water mark. If a water lacks 

sufficient flow to create such characteristics, it is not considered “tributary” under 

this rule. The agencies are aware that terms such as “gully” and “rill” may have 

different meanings throughout the country. Therefore, by grounding the definition 

of “tributary” in the final rule to the above referenced specific physical features, the 

agencies believe that confusion regarding whether a feature is a “tributary” or a 

non-jurisdictional “erosional feature” will be minimal. See the summary response 

for Section 8.4, particularly the sub-section titled, “Distinction between an 

ephemeral water and a non-jurisdictional gulley, rill or non-wetland swale.” 

Department of Public Works, City of Chesapeake, Virginia (Doc. #5612.1)

8.435 ...Since runoff from rainfall is the primary source of water for ephemeral stream flow, 

why are ephemeral streams being regulated any differently than gullies, rills and nonwetland swales? Ephemeral streams as well as ditches with less than perennial flow 

should be explicitly exempt to regulatory oversight under the CWA. (p. 3)

Agency Response: The agencies’ position in regard to tributaries is rooted in a 

science-based conclusion that such waters have a significant nexus either 

individually or in the aggregate with traditional navigable waters, interstate waters, 

and the territorial seas. Section VII of the Technical Support Document discusses 

the science supporting the agencies’ conclusion. See the summary response for 

Section 8.4, particularly the sub-section titled, “Distinction between an ephemeral 

water and a non-jurisdictional gulley, rill or non-wetland swale.” Paragraph (b) of 

the rule also excludes most ditches that are not relocated tributaries or excavated in 

tributaries. See the summary response for section 6.2, “Excluded Ditches” in this 

RTC for a discussion of how the proposed exclusions for ditches were edited and 

clarified for the final rule. 

Duke Energy (Doc. #13029)

8.436 Tributaries: The definition for tributaries should be reexamined and several key changes 

should be made:

 ...Revise the definition to include only perennial and intermittent streams. 

Ephemeral waters should be excluded, as proposed for erosional features that only 

flow in response to precipitation events (i.e. gullies, rills and nonwetland swales). 

(p. 12)

Agency Response: The agencies disagree that ephemeral tributaries should be 

excluded from waters of the United States. The agencies’ position in regard to 
Clean Water Rule Response to Comments – Topic 8: Tributaries

553

tributaries is rooted in a science-based conclusion that such waters have a 

significant nexus either individually or in the aggregate with traditional navigable 

waters, interstate waters, and the territorial seas. Section VII of the Technical 

Support Document discusses the science supporting the agencies’ conclusion. See 

the summary response for Section 8.4, particularly the sub-section titled, 

“Distinction between an ephemeral water and a non-jurisdictional gulley, rill or 

non-wetland swale.”

8.437 ...the definition of tributary does not provide any clarification on how to distinguish 

between a jurisdictional ephemeral drainage and a non-jurisdictional erosional feature 

(i.e. a gully). These features will most likely look and function very similarly, as they 

typically only carry water following precipitation events. It is also unclear how one 

would differentiate between a jurisdictional ephemeral ditch which may qualify for an 

exclusion. (p. 26)

Agency Response: See the summary response for Section 8.4, particularly the subsection titled, “Distinction between an ephemeral water and a non-jurisdictional 

gulley, rill or non-wetland swale.” The definition of “tributary” in the final rule 

requires that flow must be of sufficient volume, frequency, and duration to create 

the physical characteristics of bed and banks and an ordinary high water mark. If a 

water lacks sufficient flow to create such characteristics, it is not considered 

“tributary” under this rule. By grounding the definition of “tributary” in the final 

rule to the above referenced specific physical features, the agencies believe that 

confusion regarding whether a feature is a “tributary” or a non-jurisdictional 

“erosional feature” will be minimal. See the summary response for section 6.2, 

“Excluded Ditches” in this RTC for a discussion of how the proposed exclusions for 

ditches were edited and clarified for the final rule.

Southern Company (Doc. #14134)

8.438 As a final example of the practical deficiencies inherent in the agencies’ proposed 

approach, the new definition of “tributary” is likely to create confusion concerning 

jurisdiction over features such as gullies, rills, and swales as the agencies provide no 

discerning hydrologic or physical features that would distinguish them from jurisdictional 

ditches. Indeed, in the preamble, the agencies indicate that gullies and rills “typically” 

(but not always) lack an OHWM. 79 Fed. Reg. at 22218. Accordingly, it will be 

exceedingly difficult, if not impossible, in the field to clearly distinguish jurisdictional 

tributaries (particularly ephemeral features) and exempt gullies, rills, and non-wetland 

swales. It is worth noting that the Corps during the pendency of this rulemaking released 

two new guidance documents regarding OHWM, which is critical to the definition of 

“tributary” under the current proposal.591 Although the proposal states that the agencies 

are not changing the OHWM through the proposal, it is troubling that these guidance

 

591 See A Guide to Ordinary High Water Mark (OHWM) Delineation for Non-Perennial Streams in Western 

Mountains, Valley, and Coast Region of the United States (Aug. 2014), available at 

http://acwc.sdp.sirsi.net/client/search/asset/1036027; and see also A Review of Land and Stream Classifications in 

Support of Developing a National Ordinary High Water Mark (OHWM) Classification (Aug. 2014), available at

http://acwc.sdp.sirsi.net/client/search/asset/1036026.
Clean Water Rule Response to Comments – Topic 8: Tributaries

554

documents were issued independent of the rulemaking, without notice and comment, on a 

key element of the proposal. At a minimum, these changes should be subject to notice 

and comment requirements of the Administrative Procedure Act. (p. 36)

Agency Response: See the summary response for Section 8.4, particularly the subsection titled, “Distinction between an ephemeral water and a non-jurisdictional 

gulley, rill or non-wetland swale.” The definition of “tributary” in the final rule 

requires that flow must be of sufficient volume, frequency, and duration to create 

the physical characteristics of bed and banks and an ordinary high water mark. If a 

water lacks sufficient flow to create such characteristics, it is not considered 

“tributary” under this rule. By grounding the definition of “tributary” in the final 

rule to the above referenced specific physical features, the agencies believe that 

confusion regarding whether a feature is a “tributary” or a non-jurisdictional 

“erosional feature” will be minimal. Scientists at the Corps’ Engineer Research and 

Development Center have been performing research aimed at improving OHWM 

delineation practices across the country for over a decade. Two regional OHWM 

delineation manuals and a number of supporting research and technical reports 

have been developed to date. See also summary response 8.1.2 above. 

EcoSynthesis Scientific & Regulatory Services (Doc. #14586)

8.439 ...the combination of the principle that there is no bed-and-bank feature that is too small 

to be a tributary water of the U.S. and the wording “for any length” means that the 

Proposed Rule inevitably will regulate all gullies and minor erosion rills along with 

consensus tributaries. It also means that many or all roadside drainage ditches would be 

regulated as waters.

Regulating features whose surface water, during the brief periods when it is present, 

subsequently mixes with an incomparably greater volume of groundwater, over a great 

distance, before it could possibly contribute to other distant surface waters, is functionally 

the same thing as changing the CWA to regulate groundwater. I assume that is not the 

intent of the Proposed Rule, but that is the actual effect of its language. This is open to 

inevitable and successful legal challenge. At what point does “for any length” end? Are 

all of the hydrologic sinks in Nevada now to be regulated because somewhere at lower 

elevation, perhaps 10-50-100 miles away, there is a tributary, which the sink inflow 

channels are connected to via underground flow “for any length”?

Although it is a slippery slope to try to quantify any limit on the “for any length,” and I 

do not have a specific suggestion of replacement language, I suggest some alternatives to 

consider. For one thing, I unequivocally support retaining the “for any length” standard 

for constructed manmade features such as culverts, including large box culverts 

underneath cities. This is scientifically justified because, for practical purposes these 

features have essentially 100 percent transmissivity of the surface waters that enter the 

upslope end: there is no significant mixing with groundwater. It seems correct also to 

retain the standard for constructed features without a manmade bed (such as arch 

culverts), which essentially remain the same surface tributary although there is a piece of 

construction bridging it somewhere above. Whether inches above, or many feet, this is 

still a continuous tributary.
Clean Water Rule Response to Comments – Topic 8: Tributaries

555

Where the breaks in surface flow are natural, I would suggest that even slight evidence of 

surface flow, such as a continuous stringer of coarse sand or gravel albeit lacking a bed 

and bank should be interpreted as evidence of connectivity. Even where the natural break 

is loamy, or at least not significantly coarser than the surrounding uplands, “for any 

length” casts much to wide a net to withstand legal challenge. I would suggest that the 

overall feature would need to be substantially continuous, or the natural breaks would 

need to be no longer than some multiplier of average channel (OHWM) width up- and 

down-stream of the break. Functionally, a natural break only about 10 times the channel 

width probably doesn’t interrupt connectivity for the preponderance of annual discharge. 

But such a break 100 times longer than the channel width probably does mean that there 

is not substantial connectivity of the up-valley channel with the lower valley one. A rigid 

numerical standard would inevitably result in excessive case-by-case attention, but 

establishing a rule of thumb or concept, and suggesting that the burden of providing 

evidence bearing on connectivity or lack thereof falls upon the delineation requestor 

might provide an avenue for making site-specific determinations efficiently. If the 

delineation report fails to provide any such evidence whatsoever, then the Definition 

defaults to the “for any length” standard.

Though the actual Definition states that a channel can only be a tributary if it has both 

bed and bank and an OHWM, it would be very useful for the Rule as a whole to 

emphasize that where a bed and bank is present, but not an OHWM or other characteristic 

such as continuous stringer of wetland vegetation, then that feature is not a tributary. 

Thus, a landscape feature in silty materials, with 1) a vertical bank only at the top and not 

down at the level where water actually flows, 2) a loamy bed not consistently scoured to 

sandy or gravelly surface texture, and 3) vegetated by strictly upland vegetation (common 

examples that I observe widely in such features include squirreltail grass, sagebrush, 

rabbitbrush, and various upland or FACU non-native species), would provisionally be 

excluded as a tributary. Such a feature segment might serve to connect other features to 

establish their jurisdiction, analogously to other discussion within the Rule, but would 

otherwise be a non-tributary channel. Thus, where there is a long distance where there is 

no bed and bank, then an arroyo-form feature such as described above, then no bed and 

bank again, with no OHWM in either type of feature, this would be a non-tributary 

feature. An approach of this kind should successfully differentiate between washes that 

do and do not have significant connectivity. (p. 3-4)

Agency Response: Paragraph (b) of the final rule explicitly excludes erosional 

features, including gullies, rills and other ephemeral features that do not meet the 

definition of “tributary,” as well as most ditches that are not relocated tributaries or 

excavated in a tributary. See the summary response for section 6.2, “Excluded 

Ditches” in this RTC for a discussion of how the proposed exclusions for ditches

were edited and clarified for the final rule. Paragraph (b) of the final rule also 

makes clear that the features identified therein “are not waters of the United States 

even where they otherwise meet the terms of paragraphs (a)(1) through (a)(8)” of 

the rule. Thus, a gully, ditch or any other excluded feature may not be considered 

waters of the United States under any other provision of the rule. See summary 

response 8.3 above for discussion of discontinuity of OHWM. The definition of 

“tributary” in the final rule requires that flow must be of sufficient volume, 

frequency, and duration to create the physical characteristics of bed and banks and 
Clean Water Rule Response to Comments – Topic 8: Tributaries

556

an ordinary high water mark. If a water lacks sufficient flow to create such 

characteristics, it is not considered “tributary” under this rule. 

8.440 Another facet of the discussion above, definitely applicable in the arid West and possibly 

elsewhere, pertains to the geomorphic history of the features one observes today. In some 

cases, major precipitation events that occur very rarely may form a bed and bank where 

there is no surface flow at any time for years on end. Functionally, these features are 

actually gullies rather than tributaries, but this is not always easy to determine by 

appearance, except that genuine tributaries exhibit evidence of surface flow continuously, 

or nearly so, to the next larger downstream water. The Proposed Rule states that it intends 

to exclude gullies, but, in practice, the Rule’s language would include them.

In other features, the channel landforms date to centuries past (e.g., Little Ice Age or even 

Last Glacial Maximum), when wet periods occurred in, for example, the Intermountain 

Region. If evidence that surface flow still regularly occurs can be discerned, it is a 

tributary, albeit perhaps a much smaller one that the landform suggests. But in a relict 

feature where there is no evidence of surface flow at present, one questions the nexus 

with downstream water quality.

Often, non-tributary channels (which have a pronounced bed and bank but are separated 

from a downstream jurisdictional water by a significant distance of upland) occur on 

mountain slopes with shallow soils, in areas where the topography results in them being 

subject to brief intense rainfall events. The downslope soils may be paleo alluvial 

landforms or even currently active alluvial fans with high permeability. The fact that 

these channels are not tributary is often evidenced by the fact that they terminate 

downslope in debris flows (sometimes containing quite large particles) that are deposited 

first to one side, then to the other, below the channel, at the point on the slope where the 

water percolates and becomes groundwater. This is routinely seen in the field or even in 

close examination of NAIP imagery.

Wetland delineation procedures, and indeed the concept of ordinary high water mark, 

have always considered whether the hydrologic conditions occur on a regular basis, 

whether within each calendar year, or from year to year. The definition of tributary 

should consider this too. In some climatic areas, it is possibly not correct to restrict the 

definition only to features that exhibit surface flow every year, because even large 

arroyos may not experience flow every year (though they exhibit flow indicators such as 

stringers of gravel here or there within a defined area). But many small features that flow 

rarely and do not have a continuous bed and bank or other surface flow indicators 

(scouring to sandy or gravelly texture at the flow line within valley-shaped topography) 

to the next larger tributary have questionable connectivity.

Essentially, this is the issue of discriminating between gullies (non-jurisdictional) and 

ephemeral tributaries (jurisdictional by rule), about which the Proposed Rule specifically 

requests comment. The simplest resolution is to state that an ephemeral tributary exhibits 

evidence of regular surface flow (in at least a few years every decade) for nearly the 

entirety of its length to a confluence, whereas a gully (non-tributary channel) terminates 

downslope by percolating into lower gradient or different textured soils. If it does not 

terminate, then every event that is sufficient to cause surface flow at all will contribute 

that flow to the downstream water, ergo it is an ephemeral tributary. The connectivity 
Clean Water Rule Response to Comments – Topic 8: Tributaries

557

report explains successfully why ephemeral tributaries that flow ordinarily have the 

significant nexus that is required by the Rapanos decision, but if the definition of such 

tributaries is expanded to include all features that ever flow, no matter how rarely or 

under no matter how extreme of an event, and furthermore includes features that are 

disjunct “for any length,” then it becomes impossible to objectively justify that same 

finding when, under such precipitation events, the majority of the watershed also has just 

as much of a nexus to downstream water quality.

It is correct for requests for (non-) jurisdictional determination of the kinds of features 

discussed above to be required to include sufficient background information (soils, 

climate) and extensive, detailed observations from the field, sometimes including 

comprehensive sets of georeferenced photographs. The details may vary by District or 

ecoregion, but an applicant or requestor should have an opportunity to make a showing 

that one or more features are non-tributary channels, if he or she clearly explains the 

threshold applicable to determining that features (or hypothetical features, if none are 

present within the study area) are in fact tributary. (p. 4-5)

Agency Response: The final rule clearly requires the presence of both bed and 

banks and another indicator of OHWM, if one is not present then the water does 

not qualify as a tributary. Bed and banks can be naturally formed by repeated flow 

of water or artificially constructed out of rock, concrete, etc, however both bed and 

banks and another indicator of OHWM must be found before a water can be called 

a tributary under the rule. The agencies have concluded that flow of a sufficient 

volume, frequency, and duration create and maintain the physical characteristics of 

tributaries, such as bed and banks and another indicator of OHWM. The 

Connectivity Report supports the scientific conclusion that all features that meet 

this definition of tributary impact the physical, chemical, and biological integrity of 

downstream waters and therefore have a significant nexus to (a)(1) through (3) 

waters. While the Rule does contain exclusions for ephemeral features that do not 

meet the definition of tributary, such as gullies, rills, and non-wetland swales, 

ephemeral waters that have the physical characteristics of a tributary, including bed 

and banks and OHWM, are not excluded from jurisdiction. The preamble to the 

final rule and the Exclusion Compendium 7 provide in depth discussion of each of 

the exclusions. See summary response 8.3 for discussion of breaks in OHWM. See 

also TSD section 7 rationale supporting the final rule. In addition, the final rule has 

not changed the long standing practice of jurisdictional determination expiring after 

five years, providing temporal certainty, without ignoring the evolution of land and 

water features over time. Jurisdictional determinations are case specific and not 

done in response to hypothetical proposals. 

ERO Resources Corporation (Doc. #14914)

8.441 The proposed rule needs to clearly define the difference between tributaries and erosional 

features. It is unclear in the proposed rule how erosional features (gullies, rills, nonwetland vegetated swales) would be differentiated from tributaries, particularly in the arid 

West where ephemeral tributaries flow only briefly during and shortly after snowmelt or 

storm events. Erosional features can have physical characteristics similar to a bed and 

banks, and perhaps even an OHWM, at least after a flow event. Ephemeral drainages may 
Clean Water Rule Response to Comments – Topic 8: Tributaries

558

not have a continuous bed and banks, and/or a continuous OHWM. This guidance is 

particularly important in the arid West where the differences between an ephemeral 

drainage and gullies and rills can be minor. (p. 18)

Agency Response: See summary response for section 8.4.

American Public Power Association (Doc. #15008)

8.442 G. The Proposed Rule Provides No Basis for Distinguishing Between Erosional 

Features and Small Ephemeral Features.

The agencies propose to regulate ephemeral drainages, but exclude gullies, rills, and nonwetland swales, while failing to define any of these key terms. 79 Fed. Reg. at 22,219. 

Instead, the agencies seek comment on “how to distinguish between erosional features, 

such as gullies, which are excluded from jurisdiction, and ephemeral tributaries, which 

are categorically jurisdictional.” Id. The different treatment of these predominantly dry 

features appears to be arbitrary and the agencies do not provide any scientific basis for 

distinguishing between them. 

The proposed approach stands to cause chaos in the field resulting in confusion and delay 

as regulators struggle to distinguish between regulable ephemeral drainages and 

unregulated gullies, rills, and non-wetland swales. Indeed, if these features are so similar, 

why are erosional features categorically excluded and ephemeral drainages are 

categorically jurisdictional? The agencies should exclude ephemeral drainages from 

jurisdiction as well as erosional features like gullies, rills, and non-wetland swales. (p. 

10-11)

Agency Response: The definition of “tributary” in the final rule requires that flow 

must be of sufficient volume, frequency, and duration to create the physical 

characteristics of bed and banks and an ordinary high water mark. If a water lacks 

sufficient flow to create such characteristics, it is not considered “tributary” under 

this rule. By grounding the definition of “tributary” in the final rule to the above 

referenced specific physical features, the agencies believe that confusion regarding 

whether a feature is a “tributary” or a non-jurisdictional “erosional feature” will be 

minimal. The agencies’ position in regard to tributaries is rooted in a science-based 

conclusion that such waters have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion. In addition, see the summary response for 

Section 8.4, particularly the sub-section titled, “Distinction between an ephemeral 

water and a non-jurisdictional gulley, rill or non-wetland swale.”

Colorado River Water Conservation District, Colorado (Doc. #15070)

8.443 The terms "gully" and "rill" should be specifically defined to avoid additional confusion. 

(p. 2)

Agency Response: The definition of “tributary” in the final rule requires that flow 

must be of sufficient volume, frequency, and duration to create the physical 

characteristics of bed and banks and an ordinary high water mark. If a water lacks 

sufficient flow to create such characteristics, it is not considered “tributary” under 
Clean Water Rule Response to Comments – Topic 8: Tributaries

559

this rule. By grounding the definition of “tributary” in the final rule to the above 

referenced specific physical features, the agencies believe that confusion regarding 

whether a feature is a “tributary” or a non-jurisdictional “erosional feature” will be 

minimal. See summary response for section 8.4.

Association of Metropolitan Water Agencies et al. (Doc. #15157)

8.444 For the rulemaking to achieve its goal of increased clarity, the final rule language should 

communicate both where WOTUS starts and where WOTUS ends. In explaining the 

agencies’ intent, the EPA’s and Corps’ subject-matter experts refer to current guidance 

and preamble language. However, guidance and preamble do not have the force of law, 

and existing guidance will likely be replaced after the rule is finalized in favor of 

interpretation of the revised rule language as it is written. Consequently, in addition to the 

definitions listed above, the final rule language should provide a clear basis for:

1. Distinguishing between a tributary and water infrastructure such as stormwater 

ditches and swales. ... (p. 3)

Agency Response: The definition of “tributary” in the final rule requires that flow 

must be of sufficient volume, frequency, and duration to create the physical 

characteristics of bed and banks and an ordinary high water mark. If a water lacks 

sufficient flow to create such characteristics, it is not considered “tributary” under 

this rule. The point at which waters of the United States begin and end is based on 

the presence of those features identified in paragraph (a) of the rule. For example, 

as described in Section IV(F) of the preamble to the final rule, the upper limit of a

tributary is the point where a bed and banks and another indicator of OHWM cease 

to be identifiable. See summary response 7.4.4. about stormwater features and 6.0 

about ditches. 

Pennsylvania Independent Oil and Gas Association (Doc. #15167) 

8.445 In the Proposed Rule, EPA admits the difficulty in distinguishing between an erosional 

feature or gully and a jurisdictional water. EPA indicates that the only difference between 

these features may be the length of time that they have existed. 79 Fed. Reg. 22,218-

22,219: This type of distinction would undoubtedly cause confusion and subjective 

determinations. PIOGA requests clarification of the distinction between these features. 

(p. 18)

Agency Response: The definition of “tributary” in the final rule requires that flow 

must be of sufficient volume, frequency, and duration to create the physical 

characteristics of bed and banks and an ordinary high water mark. If a water lacks 

sufficient flow to create such characteristics, it is not considered “tributary” under 

this rule. By grounding the definition of “tributary” in the final rule to the above 

referenced specific physical features, the agencies believe that confusion regarding 

whether a feature is a “tributary” or a non-jurisdictional “erosional feature” will be 

minimal. See summary response for section 8.4. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

560

Wisconsin Electric Power Company and Wisconsin Gas LLC (Doc. #15407)

8.446 F. The Proposed Rule Provides No Basis for Distinguishing Between Erosional Features 

and Small Ephemeral Features.

The agencies propose to regulate ephemeral drainages, but excluded gullies, rills, and 

non-wetland swales while failing to define any of these key terms. 79 Fed. Reg. at

22,219. Instead, the agencies seek comment on “how to distinguish between erosional 

features, such as gullies, which are excluded from jurisdiction, and ephemeral tributaries, 

which are categorically jurisdictional.” Id. The different treatment of these predominantly 

dry features appears to be arbitrary and the agencies do not provide any scientific basis 

for distinguishing between these. (p. 7)

Agency Response: The definition of “tributary” in the final rule requires that flow 

must be of sufficient volume, frequency, and duration to create the physical 

characteristics of bed and banks and an ordinary high water mark. If a water lacks 

sufficient flow to create such characteristics, it is not considered “tributary” under 

this rule. By grounding the definition of “tributary” in the final rule to the above 

referenced specific physical features, the agencies believe that confusion regarding 

whether a feature is a “tributary” or a non-jurisdictional “erosional feature” will be 

minimal. See summary response for section 8.4. The agencies’ position in regard to 

tributaries is rooted in a science-based conclusion that such waters have a 

significant nexus either individually or in the aggregate with traditional navigable 

waters, interstate waters, and the territorial seas. Section VII of the Technical 

Support Document discusses the science supporting the agencies’ conclusion.

Southern Environmental Law Center et al. (Doc. #13610)

8.447 Agency Comment Request: The agencies’ request comment on . . . the definition of 

tributaries and provide a clear explanation of their lateral and upstream extent.

Comment: ...To the extent that there is concern that such a definition would cover 

insignificant features such as puddles, gutters, and upland roadside ditches, the agencies 

could define waters to exclude such features. Or preamble language could be drafted to 

address this issue. (p. 13)

Agency Response: Exclusions of various features from consideration as waters of 

the United States have been revised and clarified for the final rule. Paragraph (b) of 

the final rule outlines all of those excluded features, and they are also described in 

section IV(I) of the preamble to the final rule.

8.448 Agency Comment Request: The agencies’ request comment on . . . how [other features 

in a tributary system should be treated.

Comment: The overall approach used in this proposed rule should apply in this context 

too— define what is jurisdictional and what is not. Gullies, rills, and non-wetland swales 

could be considered either non-jurisdictional components of the tributary system or

simply not part of the tributary system. Either way, they should be defined as lacking the 

characteristics that make the other components of the tributary system jurisdictional. 

Such discussion should also point out that although such features may not be considered 

jurisdictional for purposes of Section 404, they may still be considered point sources 
Clean Water Rule Response to Comments – Topic 8: Tributaries

561

under Section 402, as well as surface connections to establish significant nexus. (p. 13-

14)

Agency Response: Gullies, rills, and non-wetland swales are all explicitly excluded 

from consideration as waters of the United States under paragraph (b) of the final 

rule. The definition of “tributary” in the final rule requires that flow must be of 

sufficient volume, frequency, and duration to create the physical characteristics of 

bed and banks and an ordinary high water mark. If a water lacks sufficient flow to 

create such characteristics, it is not considered “tributary” under this rule. By 

grounding the definition of “tributary” in the final rule to the above referenced 

specific physical features, the agencies believe that confusion regarding whether a 

feature is a “tributary” or a non-jurisdictional “erosional feature” will be minimal. 

Section I of the Technical Support Document provides the legal framework under 

which a ditch could be considered both a point source and a water of the United 

States.

Center for Biological Diversity, Center for Food Safety, and Turtle Island Restoration Network 

(Doc. #15233)

8.449 With respect to your treatment of gullies and rills, and their distinction with streams, we 

have already observed that streams (and tributaries) may not necessarily be characterized 

by OHWMs and that in many regions, such erosional features are of critical importance.. 

Accordingly, that characteristic is not reasonably available to distinguish a gully from a 

stream as you suggest, even if the exclusion of such erosional features of recent origin is 

scientifically warranted. 79 Fed. Reg. 22218-19. While there may be other methods of 

distinguishing erosional features from streams, as above, the conservation groups 

question the necessity of rendering these distinctions at all when the (a)(7) significant 

nexus requirement suffices to ensure that an “other water” generally will not receive 

WOTUS status where it retains no real potential to affect a traditionally jurisdictional 

water body. (p. 11)

Agency Response: See summary response for section 8.4. The definition of 

“tributary” in the final rule requires that flow must be of sufficient volume, 

frequency, and duration to create the physical characteristics of bed and banks and 

an ordinary high water mark. If a water lacks sufficient flow to create such 

characteristics, it is not considered “tributary” under this rule. Paragraph (b) of 

the final rule explicitly excludes erosional features, including gullies, rills and other 

ephemeral features that do not meet the definition of “tributary.” Paragraph (b) of 

the final rule also makes clear that the features identified therein “are not waters of 

the United States even where they otherwise meet the terms of paragraphs (a)(1) 

through (a)(8)” of the rule. Thus, a gully, ditch or any other excluded feature may 

not be considered waters of the United States under any other provision of the rule. 

Natural Resources Defense Council et al. (Doc. #15437)

8.450 2. “The agencies request comment on all aspects of the proposed definition of tributaries 

and in particular on whether and how this definition can be revised to provide increased 
Clean Water Rule Response to Comments – Topic 8: Tributaries

562

clarity as to the distinction between jurisdictional tributaries, as defined, and nonjurisdictional features such as gullies, rills and non-wetland swales.”592

We view this request for comment as an extension of the prior one. Again, we support the 

concept of including real aquatic features, and excluding those things that are not the 

result of the regular presence of water over a long period of time. Accordingly, where 

features that could be classified as “gullies,” “rills,” or “non-wetland swales” in fact are 

permanent aquatic features that actually convey water that reaches downstream navigable 

or interstate waters, they should be treated as tributaries and protected as such. The 

agencies have received some advice from the SAB to develop this distinction further; in 

its review of the Connectivity Report, the SAB differentiated between “erosional features 

like rills and gullies, which are initiated by human or natural disturbance, and longerterm, integrated headwater channels with more ecologically effective connectivity to 

downstream waters,” and points EPA to studies that provide information “on the 

transition from gullies to headwater streams.”593 (p. 61-62)

Agency Response: The final rule differentiates erosional features like gullies, rills 

and non-wetland swales from intermittent and ephemeral tributaries. While 

erosional features that do not meet the definition of “tributary” in the final rule are 

explicitly excluded from consideration as waters of the United States, ephemeral and 

intermittent tributaries are categorically considered waters of the United States. 

The agencies’ position in regard to tributaries is rooted in a science-based 

conclusion that such waters have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion. See summary response for section 8.4.

Association of State Floodplain Managers, Inc. (Doc. #19452)

8.451 We also recognize the complexity of drawing a line between regulated tributaries and 

unregulated man-made upland ditches, especially since many ditches were formed by 

modification of natural streams. However, this is a long standing problem. If uncertainty 

regarding jurisdiction in complex situations is not entirely resolved by the proposed rule, 

still the rule does not exacerbate the problem. A number of states have developed criteria 

that provide straight forward solutions to addressing these distinctions in a regulatory 

program, and we suggest that the federal agencies consult with the states to develop 

consistent criteria to distinguish between highly altered streams, regulated ditches and 

unregulated ditches. (p. 4)

Agency Response: The definition of “tributary” in the final rule requires that flow 

must be of sufficient volume, frequency, and duration to create the physical 

characteristics of bed and banks and an ordinary high water mark. If a water lacks 

sufficient flow to create such characteristics, it is not considered “tributary” under 

this rule. See summary response for section 8.4. Waters that meet the definition of 

“tributary” are categorically waters of the United States, unless they are excluded in 

 

592 79 Fed. Reg. at 22,203.

593 SAB Connectivity Review at 31.
Clean Water Rule Response to Comments – Topic 8: Tributaries

563

paragraph (b) of the final rule. See the summary response for section 6.2, 

“Excluded Ditches” in this RTC for a discussion of how the proposed exclusions for 

ditches were edited and clarified for the final rule.

The Association of State Wetland Managers (Doc. #14131)

8.452 6. The proposed rule recognizes the importance of protecting and managing stream 

networks in totality – including tributaries – to maintain the physical, chemical, and 

biological integrity of navigable waters.

...

We recognize the complexity of drawing a line between regulated tributaries and 

unregulated man-made upland ditches, especially since many ditches were formed by 

modification of natural streams. However, this is a long standing problem that is not 

exacerbated by the proposed rule.

A number of states have developed criteria that provide straight forward solutions to

addressing these distinctions in a regulatory program, and we suggest that the federal 

agencies consult with the states to develop consistent criteria to distinguish between 

highly altered streams, regulated ditches and unregulated ditches. We also recommend 

that the federal agencies consult with the states to develop or revise field procedures for 

identifying streams on a regional basis. (p. 3, 4)

Agency Response: Agency Response: Cooperative federalism is a hallmark of 

the Clean Water Act. The agencies will continue to work with our regulatory 

partners on timely development of necessary training and guidance, including the 

process for documentation of jurisdictional waters, as appropriate, to build upon 

existing working relationships, to inform stakeholders, and to ensure successful 

implementation of this rule. The definition of “tributary” in the final rule requires 

that flow must be of sufficient volume, frequency, and duration to create the 

physical characteristics of bed and banks and an ordinary high water mark. If a 

water lacks sufficient flow to create such characteristics, it is not considered 

“tributary” under this rule. Waters that meet the definition of “tributary” are 

categorically waters of the United States, unless they are excluded in paragraph (b) 

of the final rule. See the summary response for section 6.2, “Excluded Ditches” in 

this RTC for a discussion of how the proposed exclusions for ditches were edited 

and clarified for the final rule.

Texas Wildlife Association (Doc. #12251)

8.453 The Proposed Rule Fails to Provide Clarity or Predictability

... allowing for exempted features, such as groundwater, gullies and rills to serve as 

connections that can render a feature jurisdictional “adjacent water or “other water.” (p. 

4)

Agency Response: The final rule differentiates erosional features like gullies, rills 

and non-wetland swales from intermittent and ephemeral tributaries. While 

erosional features that do not meet the definition of “tributary” in the final rule are 

explicitly excluded from consideration as waters of the United States, ephemeral and 
Clean Water Rule Response to Comments – Topic 8: Tributaries

564

intermittent tributaries are categorically considered waters of the United States. 

The agencies’ position in regard to tributaries is rooted in a science-based 

conclusion that such waters have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion. See summary response for section 8.4.Section 

IV(I) of the preamble to the final rule states clearly that while the waters listed in 

the exclusions in paragraph (b) of the final rule are never waters of the United 

States, they can serve as a hydrologic connection that the agencies would consider 

under a case-specific significant nexus under paragraphs (a)(7) and (a)(8). 

8.454 F. The Proposed Rule Provides No Basis for Distinguishing Between Erosional 

Features and Small Ephemeral Features.

The agencies propose to regulate ephemeral drainages, but excludes gullies, rills, and 

non-wetland swales while failing to define any of these key terms. 79 Fed. Reg. at 

22,219. Instead, the agencies seek comment on "how to distinguish between erosional 

features, such as gullies, which are excluded from jurisdiction, and ephemeral tributaries, 

which are categorically jurisdictional." Id. The different treatment of these predominantly 

dry features appears to be arbitrary and the agencies do not provide any scientific basis 

for distinguishing between them.

The proposed approach stands to cause chaos in the field resulting in confusion and delay 

as regulators struggle to distinguish between regulable ephemeral drainages and 

unregulated gullies, rills, and non-wetland swales. Indeed, if these features are so similar, 

why are erosional features categorically excluded and ephemeral drainages categorically 

jurisdictional? The agencies should exclude ephemeral drainages from jurisdiction as 

well as erosional features like gullies, rills, and non-wetland swales. (p. 6)

Agency Response: See summary response for section 8.4. The definition of 

“tributary” in the final rule requires that flow must be of sufficient volume, 

frequency, and duration to create the physical characteristics of bed and banks and 

an ordinary high water mark. If a water lacks sufficient flow to create such 

characteristics, it is not considered “tributary” under this rule. By grounding the 

definition of “tributary” in the final rule to the above referenced specific physical 

features, the agencies believe that confusion regarding whether a feature is a 

“tributary” or a non-jurisdictional “erosional feature” will be minimal. The 

agencies’ position in regard to tributaries is rooted in a science-based conclusion 

that such waters have a significant nexus either individually or in the aggregate with 

traditional navigable waters, interstate waters, and the territorial seas. Section VII 

of the Technical Support Document discusses the science supporting the agencies’ 

conclusion. In addition, see the summary response for Section 8.4, particularly the 

sub-section titled, “Distinction between an ephemeral water and a non-jurisdictional 

gulley, rill or non-wetland swale.”

Wyoming Outdoor Council (Doc. #16528)

8.455 We recognize that under the proposed rules some tributary waters could be excluded 

from the definition of waters of the United States. This would include gullies, rills, non-
Clean Water Rule Response to Comments – Topic 8: Tributaries

565

wetland swales, and certain ditches. 79 Fed. Reg. at 22204. That said, it should be 

recognized that these exclusions are carefully defined, and if they are not met, a water 

should still be considered a tributary. See, e.g., id. at 22219 (pointing out that some 

features are called "gullies" when this is not true in a technical sense and "such streams 

where they are tributaries under the proposed definition would be considered "waters of 

the United States" regardless of the name they are given locally," and also pointing out 

that some swales can meet the regulatory definition of a wetland). (p. 3)

Agency Response: The definition of “tributary” in the final rule requires that flow 

must be of sufficient volume, frequency, and duration to create the physical 

characteristics of bed and banks and an ordinary high water mark. If a water lacks 

sufficient flow to create such characteristics, it is not considered “tributary” under 

this rule. By grounding the definition of “tributary” in the final rule to the above 

referenced specific physical features, the agencies believe that confusion regarding 

whether a feature is a “tributary” or a non-jurisdictional “erosional feature” will be 

minimal. This will also help mitigate inconsistent terminology used to identify 

various features of the landscape across the country. Only non-wetland swales are 

categorically excluded in the final rule. 

8.456 We feel these defined exclusions and exemptions should be granted with great caution 

since it is possible that these activities and features could still qualify as waters of the 

United States. 

Nominally excluded gullies can in fact be tributaries despite local mischaracterizations, 

79 Fed. Reg. at 22219. Wetland swales can be adjacent waters. Id. Some ditches can be 

waters of the United States because they meet the definition of a tributary. Id.

Jurisdictional ditches may include but are not limited to: 

Natural streams that have been altered; 

Ditches that have been excavated in "waters of the United States," including 

wetlands;

Ditches that have a perennial flow; and 

Ditches that connect two or more "waters of the United States." 

Id. at 22203. It is important for the agencies to ensure that activities and features such as 

these are not excluded as waters of the United States if the CWA objective of restoring 

and maintaining the chemical, physical, and biological integrity of the Nation's waters is 

to be met. (p. 10-11)

Agency Response: The definition of “tributary” in the final rule requires that flow 

must be of sufficient volume, frequency, and duration to create the physical 

characteristics of bed and banks and an ordinary high water mark. If a water lacks 

sufficient flow to create such characteristics, it is not considered “tributary” under 

this rule. Wetland swales are not categorically excluded features under the final 

rule. Only non-wetland swales are categorically excluded in the final rule. See the 

summary response for section 6.2, “Excluded Ditches” in this RTC for a discussion 

of how the proposed exclusions for ditches were edited and clarified for the final 

rule.
Clean Water Rule Response to Comments – Topic 8: Tributaries

566

Office of the Governor, State of Utah (Doc. #16534)

8.457 B. Gullies, Rills and non-wetland swales

The state is also concerned about the exemption for "gullies, rills and non-wetland 

swales.”594 These are exempted, but no definition is given for them. The MerriamWebster diction defines "gully" as "1: a trench which was originally worn in the earth by 

running water and through which water often runs after rain. 2: a small valley or 

gulch."595 The same dictionary offers this definition for 'rill', "channel made by a small 

stream.”596 "Swell" is then defined as "a low-lying or depressed and often wet stretch of 

land.”597 In the West, there are examples of gullies and rills which meet the common 

dictionary definition of said features, but will also have a bed, bank, and ordinary high 

water mark. They can also contribute flow during certain times of the year. These 

features could qualify it as a tributary under the definition of tributary found in the 

proposed rule. (See Exhibit B) Once again, the Proposed Rule in its current form creates 

too much uncertainty. (p. 8)

Agency Response: The final rule differentiates erosional features like gullies, rills 

and non-wetland swales from intermittent and ephemeral tributaries. While 

erosional features that do not meet the definition of “tributary” in the final rule are 

explicitly excluded from consideration as waters of the United States, ephemeral and 

intermittent tributaries are categorically considered waters of the United States. 

The agencies’ position in regard to tributaries is rooted in a science-based 

conclusion that such waters have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion. The definition of “tributary” in the final rule 

requires that flow must be of sufficient volume, frequency, and duration to create 

the physical characteristics of bed and banks and an ordinary high water mark. If a 

water lacks sufficient flow to create such characteristics, it is not considered 

“tributary” under this rule. By grounding the definition of “tributary” in the final 

rule to the above referenced specific physical features, the agencies believe that 

confusion regarding whether a feature is a “tributary” or a non-jurisdictional 

“erosional feature” will be minimal. This will also help mitigate inconsistent 

terminology used to identify various features of the landscape across the country. 

See the summary response for Section 8.4.

U.S. Senators Jeff Flake and John McCain (Doc. #1377)

8.458 We find EPA's attempt to limit federal jurisdiction by excluding gullies, rills, and swales 

from the definition of "waters of the U.S." encouraging, though more clarity is needed on 

what these exclusions actually encompass. We would find any distinctions drawn 

between such features and small ephemeral washes troubling. Due to the lack of 

vegetation resulting in clearer evidence of flow than would occur in mare highly 

 

594 See 79 Fed. Reg. 22263.

595 Merriam-Webster's Collegiate Dictionary, eleventh edition, 2004.

596 Id.

597 Id.
Clean Water Rule Response to Comments – Topic 8: Tributaries

567

vegetated areas, similar features that may ultimately be considered by EPA swales or rills 

in other parts of the country would likely be determined to have an ordinary high water 

mark and therefore subject to regulation in the arid Southwest. (p. 2)

Agency Response: The final rule differentiates erosional features like gullies, rills 

and non-wetland swales from intermittent and ephemeral tributaries. While 

erosional features that do not meet the definition of “tributary” in the final rule are 

explicitly excluded from consideration as waters of the United States, ephemeral and 

intermittent tributaries are categorically considered waters of the United States. 

The agencies’ position in regard to tributaries is rooted in a science-based 

conclusion that such waters have a significant nexus either individually or in the 

aggregate with traditional navigable waters, interstate waters, and the territorial 

seas. Section VII of the Technical Support Document discusses the science 

supporting the agencies’ conclusion. The definition of “tributary” in the final rule 

requires that flow must be of sufficient volume, frequency, and duration to create 

the physical characteristics of bed and banks and an ordinary high water mark. If a 

water lacks sufficient flow to create such characteristics, it is not considered 

“tributary” under this rule. By grounding the definition of “tributary” in the final 

rule to the above referenced specific physical features, the agencies believe that 

confusion regarding whether a feature is a “tributary” or a non-jurisdictional 

“erosional feature” will be minimal. See the summary response for Section 8.4.

Environmental Technology Consultants (Doc. #2597)

8.459 What is the difference between a gully or rill and a seasonal stream? The new definitions 

would appear to find a significant nexus between navigable waters and the seasonal 

streams that feed them, however gullies and rills and non-wetland swales appear to be 

excluded from the definition. We need field actionable definitions for these terms. (p. 1)

Agency Response: The definition of “tributary” in the final rule requires that flow 

must be of sufficient volume, frequency, and duration to create the physical 

characteristics of bed and banks and an ordinary high water mark. If a water lacks 

sufficient flow to create such characteristics, it is not considered “tributary” under 

this rule. By grounding the definition of “tributary” in the final rule to the above 

referenced specific physical features, the agencies believe that confusion regarding 

whether a feature is a “tributary” or a non-jurisdictional “erosional feature” will be 

minimal. See the summary response for Section 8.4. Scientists at the Corps’ 

Engineer Research and Development Center have been performing research aimed 

at improving OHWM delineation practices across the country for over a decade. 

Two regional OHWM delineation manuals and a number of supporting research 

and technical reports have been developed to date.

Whitman, Requardt & Associates, LLP (Doc. #1330)

8.460 I support the rulemaking’s attempt to clearly define the issue of jurisdiction of ephemeral 

tributaries, ditches and erosion gullies. Our experience in the field is that under current 

rules and guidance, in some cases, the COE is taking jurisdiction over ditches and 

erosional gullies, using the CWA guidance concerning the presence of a “OHW mark, or 

bed and bank”. Similar to the extensive effort made to date to define wetlands from non-
Clean Water Rule Response to Comments – Topic 8: Tributaries

568

wetlands, a similar effort should be made to provide clear guidance concerning the 

difference between a natural ephemeral channel, a jurisdictional ditch, a nonjurisdictional 

ditch and a erosional gully...

The Rulemaking makes the statement that gullies are easily distinguished from natural 

ephemeral channels. While I would agree, we are finding a number of COE staff who are 

taking all forms of “channels” – regardless of origin, age, landscape position, etc. that 

might be used to differentiate between gullies and tributaries. The key issue seems to be 

with the definition of a “OHW” mark and “Bed and Bank”. Gullies can be considered to 

have a bed and bank (sides and bottom), and because gullies are scour features, they can 

be said to have a “OHW” mark. The rule making is correct in excluding gullies from 

jurisdiction, but more guidance is needed to help permitees and agency staff consistently 

separate gullies from tributaries. (p. 1)

Agency Response: The definition of “tributary” in the final rule requires that flow 

must be of sufficient volume, frequency, and duration to create the physical 

characteristics of bed and banks and an ordinary high water mark. If a water lacks 

sufficient flow to create such characteristics, it is not considered “tributary” under 

this rule. By grounding the definition of “tributary” in the final rule to the above 

referenced specific physical features, the agencies believe that confusion regarding 

whether a feature is a “tributary” or a non-jurisdictional “erosional feature” will be 

minimal. See the summary response for Section 8.4. Scientists at the Corps’ 

Engineer Research and Development Center have been performing research aimed 

at improving OHWM delineation practices across the country for over a decade. 

Two regional OHWM delineation manuals and a number of supporting research 

and technical reports have been developed to date.

8.5. SUPPLEMENTAL COMMENTS ON TRIBUTARIES

Specific Comments

Anonymous (Doc. #3300.1)

8.461 Case 3 Local Streets with Curb and Gutter

My question here is does curb and gutter, which contributes a significant amount of flow 

to receiving tributaries, now become a nexus and become Waters of the United States? It 

sounds a little far-fetched but when you consider the volumes of flow contributing to 

wetlands, estuaries and tributaries it questions where to proposed rule starts and stops 

with adjacent contributing factors. (p. 4)

Agency Response: Curb and gutter has never been a waters of the U.S. and the 

final rule does not change that. The final rule clearly requires the presence of both 

bed and banks and another indicator of OHWM, if one is not present then the water 

does not qualify as a tributary. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

569

L. Banks (Doc. #5554.2)

8.462 5. I also believe the use of the word 'tributary' in the proposed rule could easily be 

interpreted to extend jurisdiction right up the field ditches to the water furrows. Again 

EPA stated in the public meeting that they needed the authority to regulate water off the 

farm-this would have then to include the use of the land, since water in the tribs results as 

runoff from the land. (p. 1)

Agency Response: Waters of the U.S. have always been limited to water features, 

which has not changed in the final rule. The final rule clearly requires the presence 

of both bed and banks and another indicator of OHWM, if one is not present then 

the water does not qualify as a tributary. See response to comments 6 about ditches 

and 7 about exclusions and exemptions for certain agricultural and stormwater 

activities.

Anonymous (Doc. #7447)

8.463 The CWA has achieved most of the goals originally set forth and we are happy for that. 

The new (and expanded) definition of waters of the US would regulate every draw, wash, 

gully and dip in the country. Where are the because by definition, all lands and almost 

every square foot of land would be under the jurisdiction of the EPA. In the original act, 

waters of the US were perennial and NAVIGABLE. Let’s keep it that way or at least 

define and map all waters that are perennial and run at a minimum of 'X' cps. We need a 

scientifically defined standard. Once the minimal qualification is defined (for example, 

all perennial streams exceeding one cubic foot per second) and mapped, then all other 

waters would be regulated by the state. If a defined stream was found to be impaired, the 

EPA could work with the state to find and correct the problem. This would be a very 

manageable solution. (p. 1)

Agency Response: See summary response section 8.1.2: Use of OHWM 

inappropriate/appropriate – will lead to over/under coverage of features for a 

discussion of the longstanding regulation of non-perennial streams. Jurisdictional 

determinations are conducted on a case by case basis and expire after five years 

because the hydrologic, climatic and fluvial circumstances of any one site change 

over time, resulting in changes to the extent of jurisdiction. See responses to 

scientific basis for definition of tributary and distinction from rills and gullies.

Office of the Administrator, Science Advisory Board, U.S. Environmental Protection Agency 

(Doc. #7531)

8.464 Tributaries

There is strong scientific evidence to support the EPA’s proposal to include all tributaries 

within the jurisdiction of the Clean Water Act. Tributaries, as a group, exert strong 

influence on the physical, chemical, and biological integrity of downstream waters, even 

though the degree of connectivity is a function of variation in the frequency, duration, 

magnitude, predictability, and consequences of physical, chemical and biological 

processes.

The Board advises the EPA to reconsider the definition of tributaries because not all 

tributaries have ordinary high water marks. An ordinary high water mark may be absent 
Clean Water Rule Response to Comments – Topic 8: Tributaries

570

in ephemeral streams within arid and semi-arid environments or in low gradient 

landscapes where the flow of water is unlikely to cause an ordinary high water mark. The 

Board advises the agency to consider changing the wording in the definition to “bed, 

bank, and other evidence of flow.” In addition, tributaries are not typically defined to 

include lentic systems (e.g., lakes, ponds, wetlands). Thus, the EPA may want to consider 

whether flow-through lentic systems should be included as adjacent waters and wetlands, 

rather than as tributaries. (p. 2)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. The final rule clearly 

requires the presence of both bed and banks and another indicator of OHWM, if 

one is not present then the water does not qualify as a tributary. Wetlands, lakes, 

ponds, and other features lacking a bed and banks and/or OHWM are no longer 

defined as tributaries in the Final Rule, but may be considered jurisdictional 

“waters of the United States” as adjacent waters or similarly situated waters with a 

significant nexus to (a)(1) through (3) waters as suggested. As noted in the 

comment, the Connectivity Report supports the scientific conclusion that all 

features that meet this definition of tributary impact the physical, chemical, and 

biological integrity of downstream waters and therefore have a significant nexus to 

(a)(1) through (3) waters. For a further discussion of the limits of CWA jurisdiction 

in regards to tributaries and the use of OHWM see the TSD. 

The agencies did not conclude that other evidence of flow would be a sufficiently 

specific or identifiable in the field to establish tributaries as a category of waters 

that is similarly situated with a significant nexus to (a)(1) through (3) waters. On the 

other hand, the agencies have decades of experience with the identification of 

OHWM across the country and are familiar with functions streams with OHWM 

support and their importance to downstream waters while making relatively 

permanent and significant nexus determinations since 2008. The identification of 

OHWM across the country and especially in the west has been the focus of 

significant effort for more than a decade and resulted in the creation of several 

technical guides and background documents which have improved the accuracy and 

consistency of OHWM determinations while also expanding the agencies’ 

familiarity with the various indicators of flow and OHWM found in rivers and 

streams across the western U.S.

Board of Douglas County Commissioners, Castle Rock, CO (Doc. #8145)

8.465 Under the Proposed Rule, a tributary (e.g., manmade or natural ditch/channel/culvert) is 

jurisdictional if it has a bed, bank, and an OHWM. This jurisdiction is not affected by 

extremely rare flow or disconnected surface flow to downstream WOUS. This approach 

ignores the highly variable regional surface hydrology characteristics. Certainly, the 

Proposed Rule could provide allowances for semi-arid Colorado landscapes where 

features may have concentrated surface runoff once every two years, but do not require 

the same CWA protection as seasonal waterways. (p. 15)

Agency Response: See summary response in Sections 8.1 and 8.1.1 Relevance of 

flow regime. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

571

Terry E. Branstad, Governor, State of Iowa et al. (Doc. #8377)

8.466 [T]he definitions will increase confusion and invite inconsistency of approaches for 

making jurisdictional determinations. For example, tributaries are defined as 

“contributing flow” to other waters. It would be more appropriate to clearly state that 

tributaries should have perennial or relatively permanent flow in order to be considered 

jurisdictional, to avoid the potential expansion of jurisdiction which such a broad 

definition invites. (p. 6)

Agency Response: See summary response in Section 8.1.1 Relevance of flow 

regime. 

Southern California Association of Governments (Doc. #8534.1)

8.467 The rule notes that the uplands within floodplains are never Waters of the U.S., but 

without requiring the physical presence of a defined OHWM, jurisdictional areas could 

easily be expanded. Indeed this already takes place in practice as different regulators 

interpret OHWM differently; some as a mark from a 2-year storm, others as a mark from 

a 20 year event. (p. 2)

Agency Response: Waters of the U.S. have always been limited to water features, 

which has not changed in the final rule. See summary response section 8.1.2: Use of

OHWM inappropriate/appropriate – will lead to over/under coverage of features

for a discussion of how regional variation in hydrology, climate and other factors 

continue to guide the agencies’ identification of OHWM. 

B. Forman (Doc. #9065)

8.468 As we compare the reach of the proposed WOTUS with the landscape of South Dakota, it 

quickly becomes apparent that most of these features should not fall under the scope of 

the Clean Water Act. Many of these “waters” are actually landscape features that are dry 

most of the time, or have water in them for only short periods of time. Many are too 

remote to merit the type of regulatory burden that would imposed by the Clean Water 

Act. Dry drainage features will never be fishable and swimmable and do not need to be 

made jurisdictional in order for us to work together to protect the quality of waterways 

that are clearly jurisdictional. (p. 1)

Agency Response: See summary response section 8.1.2: Use of OHWM 

inappropriate/appropriate – will lead to over/under coverage of features. See 

responses distinguishing rills, gulleys and landscape features.

Michael Richard (Doc. #9291)

8.469 Wetlands which meet the three criteria (wetland hydrology, vegetation and soils) and are 

not exempt (e.g. a stock tank), should be considered a jurisdictional wetland. It is my 

hope as an ecologist and as an environmental consultant that the proposed rule uses the 

overwhelming scientific data documenting the interconnectedness of wetlands to do away 

with the “isolated” wetland designation. As a scientist, I believe the data demands 

regulations and guidance be changed to support the initial goal of the CWA; improved 

water quality and wetland conservation.
Clean Water Rule Response to Comments – Topic 8: Tributaries

572

Despite the science supporting a unified hydrologic cycle, today wetlands designated as 

“non-jurisdictional” or isolated are be impacted without regulatory issue, ad nauseum. 

Wetlands currently considered isolated play an important role in supporting the physical, 

chemical and biological integrity of the landscape: and yet they are removed from 

regulation under USACE current guidance (Gibbons, 2003). (p. 1)

Agency Response: See executive summary of the Preamble for discussion of the 

legal limitations on the scope of waters of the U.S. 

8.470 Physical, Chemical and Biological Connections

The hydrologic cycle is a basic tenet of science taught early in schools and generally 

accepted as truthful. The hydrologic cycle demonstrates the interconnectedness of all 

waters through subsurface and surface connections (NOAA, Retrieved 9/30/2014). 

Research shows that “isolated” wetlands are connected by subsurface pathways, and such 

connections are significant (Devito, K.J., et al 1996).

The field of hydrogeology specifically studies the connections and subsurface pathways 

through which water moves. Examples of the interconnectedness of wetlands with 

groundwater are overwhelming and obvious; disregard for this data by regulations and 

agencies is shameful. If contaminates were introduced into a wetland, pollution of 

groundwater and nearby streams is the immediate concern. This is the basic scientific 

concept upon which many pollution control programs and environmental regulations: 

Storm Water Pollution Prevention Plans, National Pollutant Discharge Elimination 

System and Texas Surface Water Quality Standards.

Biological connections between wetlands are widely documented but largely discounted 

by regulations. Herpetofauna are the most documented due to their biological ties to 

aquatic habitats and noteworthy sensitivity to water quality (Gibbons, 2003). Wetlands 

may be surrounded by uplands and “geographically isolated,” yet still play a part in the 

overall function of the landscape. Reptiles, amphibians, birds and mammals using an 

isolated wetland are not confined to a single wetland and are known to migrate between 

aquatic resources. Similarly, isolated wetland are a refuge for certain species and may 

contain rare and unique assemblages (i.e., vernal pools, pocosins, etc). (p. 1)

Agency Response: See TSD section 7 on for discussion of the connections between 

tributaries and downstream waters and section 8 for discussion of connections to 

adjacent waters. 

RiverStone Group, Inc. (Doc. #10742)

8.471 Contrary to the claims of the EPA and the Corps, the proposed rule will actually cause 

more confusion than clarity. The agencies "categorical" inclusion of all tributaries 

defined by an observed "mark" on the landscape and its regulation of wetlands and waters 

adjacent to tributaries based on vague "neighboring," "riparian," "floodplain" and 

"shallow subsurface" connection criteria makes it virtually impossible to know what 

areas are regulated and what areas are not. (p. 2)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. The final rule clearly 

requires the presence of both bed and banks and another indicator of OHWM, if 
Clean Water Rule Response to Comments – Topic 8: Tributaries

573

one is not present then the water does not qualify as a tributary. Wetlands, lakes, 

ponds, and other features lacking a bed and banks and/or OHWM are no longer 

defined as tributaries in the Final Rule, but may be considered jurisdictional 

“waters of the United States” as adjacent waters or similarly situated waters with a 

significant nexus to (a)(1) through (3) waters. 

County of Henry, Collinsville, Virginia (Doc. #10949)

8.472 The concept of groundwater should be further explained and defined with the Rule as it 

relates to jurisdictional connections. Furthermore, the Rule proposes to regulate features 

within the upper reaches of the watershed that would not previously have been subject to 

CWA jurisdiction via non-jurisdictional connections. This new approach may extend 

regulatory oversight of the CWA over features that were not previously regulated: 

therefore, the County does not support the expansion of regulatory oversight under the 

CWA further into the watershed through confined surface hydrologic connections or 

shallow subsurface groundwater connections. (p. 2 – 3)

Agency Response: Waters of the U.S. has never included groundwater and does 

not cover groundwater under the final rule. See summary response section 8.1.2: 

Use of OHWM inappropriate/appropriate – will lead to over/under coverage of 

features for discussion of the historic and current extent of waters of the U.S. 

Anonymous (Doc. #11304)

8.473 Secondly, the definition of a tributary that includes wetlands is perhaps ecologically 

sound, but is confusing in the context of the rule because wetlands lack an OHWM, bed 

and banks. I agree with the alternative of separating wetlands from the tributary definition 

and leaving wetlands to be under jurisdiction as "adjacent waters." Though I personally 

can see possible connections over "debris piles, boulder fields or a stream that flows 

underground," I think further definition for these vague land breaks could be useful for 

the proposal as well. (p. 1)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. The final rule clearly 

requires the presence of both bed and banks and another indicator of OHWM, if 

one is not present then the water does not qualify as a tributary. Wetlands, lakes, 

ponds, and other features lacking a bed and banks and/or OHWM are no longer 

defined as tributaries in the Final Rule, but may be considered jurisdictional 

“waters of the United States” as adjacent waters or similarly situated waters with a 

significant nexus to (a)(1) through (3) waters. Regarding the discussion of 

connections, the Corps and EPA plan to continue to build on the more than a 

decade of effort spent improving the consistency and rigor of OHWM identifications

through the development of OHWM delineation manuals which describe the range 

of site conditions and regionally specific factors to consider when evaluating breaks 

in OHWM. 

Anonymous (Doc. #11350)

8.474 The proposed rule clarifies the types of ditches that are excluded from jurisdiction; 

however, it is possible that ditches currently identify as non-jurisdictional may in the 
Clean Water Rule Response to Comments – Topic 8: Tributaries

574

future be found jurisdictional waters of the U.S. under the proposed rule. In the same 

respect, man-made drainage canals that are currently not considered jurisdictional could 

be considered jurisdictional under these rules. We request clarification as to the 

application of these rules on these ditches and canals given the proposed definitions of 

tributaries, adjacent waters, other waters and traditional navigable waterways.

Request clarification on what it means to contribute flow. (p. 1)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. The final rule clearly 

requires the presence of both bed and banks and another indicator of OHWM, if 

one is not present then the water does not qualify as a tributary. Wetlands, lakes, 

ponds, and other features lacking a bed and banks and/or OHWM are no longer 

defined as tributaries in the Final Rule, but may be considered jurisdictional 

“waters of the United States” as adjacent waters or similarly situated waters with a 

significant nexus to (a)(1) through (3) waters. See summary response 6.1 for 

discussion of flow in ditches and canals and summary response 6.2 for a discussion

of excluded ditches. 

T. Walsh (Doc. #11437)

8.475 1. I agree that the connectivity science supports designating all tributaries to traditional 

navigable waters as Waters of the United States.

2. I agree that the connectivity science supports designating wetlands adjacent to or 

neighboring (i.e., in the floodplain/riparian area) traditional navigable waters and their 

tributaries as Waters of the United States. (p. 1)

Agency Response: Comment noted.

Anonymous (Doc. #11481)

8.476 The new rule indicates that ditches that do not contribute flow, either directly or through 

another water, to a traditional navigable water, interstate water, the territorial seas or an 

impoundment of a jurisdictional water are not considered jurisdictional under the new 

rule, however the term ditch and swale can be used interchangeably and there is no 

technical distinction made between the two in the new rule. The following excerpt is 

confusing and seems to contradict the previous exemptions of ditches/swales that do not 

contribute flow:

Non-wetland natural and man-made swales would not be waters of the United States 

under this proposal. In certain circumstances, however, swales include areas that meet the 

regulatory definition of wetlands. Swales generally are considered wetlands when they 

meet the applicable criteria in the Corps of Engineers Wetland Delineation Manual and 

the appropriate regional supplement to that Wetland Delineation Manual. Wetland swales 

would be evaluated as adjacent waters under proposed (a)(6) or as other waters under 

proposed (a)(7) depending upon whether they meet the proposed definition of adjacent. 

Swales are distinct from streams in that they are non-channelized, shallow trough-like 

depressions that carry water mainly during rainstorms or snowmelt. Report at A-19. 

Swales typically lack the OHWM that is characteristic of jurisdictional streams. The

agency’s request comment on how they could provide greater clarity on how to 
Clean Water Rule Response to Comments – Topic 8: Tributaries

575

distinguish swales, which are excluded from jurisdiction, and ephemeral tributaries, 

which are categorically jurisdictional.

Swales that carry water during rainstorms or snowmelt oftentimes contribute flow either 

directly or through another water to a TNW, Interstate water, territorial seas, or 

impoundments of a jurisdictional water. So in this regard, although swales may not have 

OHWM, they would be regulated. (p. 1 – 2)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. The final rule clearly 

requires the presence of both bed and banks and another indicator of OHWM, if 

one is not present then the water does not qualify as a tributary. Wetlands, lakes, 

ponds, and other features lacking a bed and banks and/or OHWM, such as wetland 

swales, are no longer defined as tributaries in the Final Rule, but may be considered 

jurisdictional “waters of the United States” as adjacent waters or similarly situated 

waters with a significant nexus to (a)(1) through (3) waters. This change simplifies 

the field evaluation by focusing on the field characteristics, OHWM and bed and 

banks or a delineated wetland, which then determine the jurisdictional review 

standard to apply, adjacency or tributary. See summary response 6.1 for discussion 

of flow in ditches, summary response 6.2 for a discussion of excluded ditches, and 

summary response 8.1 for general discussion of tributaries. 

Norton County Road & Bridge (Doc. #11746)

8.477 Expansion of Jurisdiction

We disagree with numerous statements in the federal register that the proposed definition 

that the regulatory jurisdiction is narrower than that under the existing regulations. While 

there are some proposed exemptions, such as ditches in uplands, these exemptions were 

unofficially in place already and were never considered waters of the US except under 

unusual circumstances. The inclusion of all tributaries as waters of the US is a major 

expansion of actual practice. Typically ephemeral channels upstream of the blue lines on 

a USGS contour map were normally not considered waters of the US by the general 

public. On occasion a 404 permit would be requested on larger projects, but the general 

public ignored any federal jurisdiction, and to our knowledge the Corps and EPA has 

seldom pursued private land owners that failed to get a permit for work on these 

headwater ephemeral channels. So in our view the proposed definition of waters of the 

US will include all ephemeral channels and doubles or triples the actual miles of channels 

regulated. (p. 1)

Agency Response: See summary response 8.1.1 and 8.1.2 for discussion of the 

historic and current extent of jurisdiction in headwater and ephemeral streams. 

The extent of federal jurisdiction does not change based public perception or actions 

taken in violation of the regulatory requirements. 

8.478 Waters of the US designation for ephemeral channels:

We disagree with your attempt to include all of a reach of an ephemeral channel as waters 

of the US. Following an ephemeral channel up the watershed it eventually becomes an 

erosional feature that rarely carries water, and when it does the water quality is 

predominantly based on the quality of the water reaching the channel and physical, 
Clean Water Rule Response to Comments – Topic 8: Tributaries

576

biological and chemical processes in the channel are minimal due to contact time so there 

is no significant nexus to downstream water quality.

The proposed regulations based on this faulty study made a giant leap to all tributaries, 

because they treated the tributary as an undividable unit rather than a linear system. There 

was no scientifically valid threshold determined where along a tributary there is a 

significant nexus to downstream water quality. (p. 2)

Agency Response: See summary response 8.1 and 8.1.1.

8.479 Ordinary High Water

The definition of a tributary is based on having a bed and bank plus an ordinary high 

water mark. On ephemeral channels there is rarely water in the channel so an ordinary 

high water mark is usually speculation. This matter is so confusing to Corps staff that the 

determination of ordinary high water is buried somewhere in regulatory guidance letters. 

Usually in first order ephemeral channels the ordinary high water mark cannot be 

determined and current practice is to say if the tributary (no matter how small) has banks 

that it has an ordinary high water mark. This bureaucratic isolated decision, that if a 

channel has banks it has an ordinary high water mark, greatly extended the upstream 

extent of ephemeral tributaries to what are basically gullies or erosional features. By 

current interpretation a 1 ft. wide and 1 ft. deep channel is considered waters of the 

United States by regulators, but what citizen would believe that the federal government 

claims jurisdiction to such a small featured. Since the ordinary high water mark is so 

important on determining if a channel is considered waters of the US that this definition 

should be open for public comment and peer review. (p. 2)

Agency Response: The final rule clearly requires the presence of both bed and 

banks and another indicator of OHWM, if one is not present then the water does 

not qualify as a tributary. See also summary response to comments 8.1.2. 

Anonymous (Doc. #11761)

8.480 It can also be argued that geographically isolated wetlands in the northern Great Plains 

region are in fact connected to other jurisdictional waters by groundwater connectivity 

(Van der Kamp and Hayashi 1998, 2009; Whigham and Jordan 2003; Winter and 

LaBaugh 2003), by surface water connectivity following intense precipitation events 

(Leibowitz 2003a,b; Leibowitz and Vining 2003; Winter and LaBaugh 2003). In areas of 

rolling topography, characteristic of the western Prairie Pothole region, isolated wetlands 

can connect to adjacent surface-water bodies during periods of abundant precipitation and 

high water levels. In areas of relatively flat topography, surface water connectivity among 

wetlands is often temporal during unusual precipitation events. It has been clearly 

demonstrated that southern Great Plains playas are important zones of recharge to the 

High Plains aquifer and are not strictly evaporative pans (Cronin and Myers 1964; 

Osterkamp and Wood. 1987; Gurdak and Roe 2009; 2010). (p. 1)

Agency Response: See TSD section 8 for discussion of adjacent waters and section 

9.A for discussion of five subcategories of waters that are similarly situated. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

577

Jack Kearns (Doc. #11860)

8.481 Preserving wetlands through regulation is extremely important these days, but any 

proposed rule must conform to case law. Current post-Rapanos cases require that a 

wetlands have a significant nexus to downstream water quality, demonstrated by 

evidence of flowing water, bed and bank, OHWM. See generally Kerns, Cry Me a Nexus, 

National Wetlands Newsletter, volume 36, Number 5, Sept/Oct 2014. I do not believe 

that case law supports federal jurisdiction of wetlands connected by an ephemerally 

flowing tributary to a downstream TNW. On page 22202 of the Federal Register Vol. 79, 

No. 76, the proposed rule preamble states “The flow in the tributary may be ephemeral...” 

I do not think it can be proven that an ephemeral tributary will have sufficient flow, over 

time, to show significant pollutant flow downstream, and I would not want to defend the 

agency on such a position. See the recent case of US. Hamilton, 952 F. Supp. 2d 1271 (D. 

Ct. Wyoming 2013). “Permanence under the plurality test refers to whether flow exists in 

a channel over a period of time...what matters is not the amount of water flowing in a 

given channel but whether water is flowing in that channel.” Ephemeral flow in a 

tributary is so minimal over time that downstream water quality will not be significantly 

affected. Even intermittent tributaries may be difficult to prove under the evidentiary 

proof (agency documentation) now required in the administrative record. (p. 1)

Agency Response: See summary response 8.1.2. 

Vicki Watson (Doc. #12081)

8.482 I also feel strongly that any streams that have a bed, bank, and Ordinary High Water 

Mark should be included in the definition of the “waters of the United States.” (p. 1)

Agency Response: The final rule requires the presence of both bed and banks and 

another indicator of OHWM to qualify as a tributary. 

Office of the Board Attorney, Board of Supervisors Jackson County, Mississippi (Doc. #12262)

8.483 I. The proposed rule could drastically increase the number of Jackson Countyowned public infrastructure ditches subject to the Clean Water Act.

EPA and the Corps take the position that the proposed definition is fully consistent with 

long-standing practice and historical implementation. 79 Fed. Reg. at 22192. However, 

the new definition adds a number of new and unclearly defined terms that could trigger 

per se CWA jurisdiction over publicly-owned infrastructure ditches.

For example, the proposed rule would effectively expand the reach of CWA jurisdiction 

by dictating that all "tributaries" and "adjacent waters including wetlands" have a 

significant nexus and therefore are categorically jurisdictional. 79 Fed. Reg. at 22193. 

The proposed rule broadly defines "tributaries" as any water that is "physically 

characterized by the presence of a bed and banks and ordinary high water mark" or any 

wetland lake or pond regardless of its physical characteristics that "contributes flow 

either directly or through another water to waters of the United States." 79 Fed. Reg. at 

22201. Under this new provision, many man-made conveyances, including ditches, could 

become automatically jurisdictional without a case-by-case analysis or any regard to 

whether its flow is perennial, intermittent, or ephemeral. 79 Fed. Reg. at 22199, 22203-

04. (p. 2)
Clean Water Rule Response to Comments – Topic 8: Tributaries

578

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. The final rule clearly 

requires the presence of both bed and banks and another indicator of OHWM, if 

one is not present then the water does not qualify as a tributary. Wetlands, lakes, 

ponds, and other features lacking a bed and banks and/or OHWM are no longer 

defined as tributaries in the Final Rule, but may be considered jurisdictional 

“waters of the United States” as adjacent waters or similarly situated waters with a 

significant nexus to (a)(1) through (3) waters. See summary response 8.1.1 and 6.1 

for the relevance of flow and summary response 6.2 for excluded ditches.

8.484 The proposed rule also states that a wetland may be considered "neighboring" and thus 

"adjacent" if the ditch connects the wetland to a tributary. Id. When combined with the 

automatic jurisdictional grant for the previously-described tributaries, it becomes unclear 

how currently exempt ditches would be distinguishable from jurisdictional ditches. Thus, 

rather than clarifying, the proposed rule will, at best, add to the confusion and uncertainty 

surrounding the meaning of "waters of the United States," particularly in regards to 

streets, gutters, roadside and drainage ditches, and flood channels. At worst, it would—

intentionally or unintentionally—lead to the unnecessary and unjustified regulation of 

many more ditches. (p. 3)

Agency Response: See summary response 6.2 for a discussion of excluded ditches 

and TSD section 8.B for discussion of connections for neighboring waters.

Mesa County, Colorado Board of County Commissioners (Doc. #12713)

8.485 Normally Dry Tributaries: In Mesa County, many tributaries to TNWs have flow only 

during and immediately following precipitation events. These ephemeral tributaries may 

be considered jurisdictional under the current regulations, if there is a "significant nexus" 

to a receiving TNW. For a feature that conveys small volumes of flow very infrequently 

(such as once or twice a year) to a large receiving TNW, the USACE could make a 

determination that the feature does not have a "significant nexus" and therefore is not 

WOUS. Under the Proposed Rule, this discretion would be taken away from the USACE 

and all tributaries, regardless of the flow regime, would be considered WOUS. In 

Colorado, many small ephemeral drainages would likely be considered WOUS under the 

Proposed Rule, and impacts to them would likely require Section 404 permitting. As 

discussed above additional permitting can be very expensive and time consuming for 

projects. (p. 3)

Agency Response: See summary response 8.1.1.

Milan Township Board of Trustees (Doc. #13044)

8.486 For example,

 Wetlands should not be considered “tributaries” in the final rule, as they should 

have to meet “adjacency” or “significant nexus” tests associated with “adjacent” 

or “other waters” to be considered “waters of the U.S.” (p. 1)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. The final rule clearly 

requires the presence of both bed and banks and another indicator of OHWM, if 
Clean Water Rule Response to Comments – Topic 8: Tributaries

579

one is not present then the water does not qualify as a tributary. Wetlands, lakes, 

ponds, and other features lacking a bed and banks and/or OHWM are no longer 

defined as tributaries in the Final Rule, but may be considered jurisdictional 

“waters of the United States” as adjacent waters or similarly situated waters with a 

significant nexus to (a)(1) through (3) waters. 

Jason Reott (Doc. #13199)

8.487 I suggest EPA/Corps change the proposed WOTUS rule in the following manner:

 Under Sec. 328.3(a)(6), and all pertinent sections, deletion of the words “All 

waters, including.” This change still allows EPA/Corps to find adjacent water 

bodies, such as lakes or ponds, to be waters of the United States through 

determination of a significant nexus to the tributary system, under 328.3(a)(7) but 

not by rule. As amended, the section would read:

328.3(a)(6)” Wetlands adjacent to a water identified in paragraphs (a)(1) 

through (5) of this section; and598”

After accepting my suggestion, EPA/Corps will be able to:

 Continue to protect traditionally navigable waters of the United States;

 Continue to protect wetlands adjacent to traditionally navigable waters;

 Continue to protect wetlands adjacent to non-navigable tributaries of traditionallynavigable waters where the tributaries typically flow year-round or have 

continuous flow at least seasonally (e.g., typically three months);

 Continue to protect wetlands that directly abut such tributaries.

Additionally, EPA/Corps will have jurisdiction by rule to:

 Protect all natural tributaries, as defined in the rule (“The term tributary means a 

water physically characterized by the presence of a bed and banks and ordinary 

high water mark, as defined at 33 CFR 328.3(e), which contributes flow, either 

directly or indirectly, to a water identified in paragraphs (a)(1) through (4)”)599; 

and

 Protect “other waters,” including “isolated wetlands,” lakes, ponds and nearby 

bodies of water with a significant nexus to any tributary, as decided on a case-bycase basis.

(Bold type indicates consistent with the EPA/Corps’ Joint Memorandum dated Dec. 2, 

2008600- i.e., pre-WOTUS rule jurisdiction) (p. 2)

 

598 79 FR 22863

599 79 FR 22263 (April 21, 2014), Sec. 328.3(a)(5), emphasis in original

600 Environmental Protection Agency/Army Corps of Engineers, “Clean Water Act Jurisdiction Following the U.S. 

Supreme Court’s Decision in Rapanos v. United States & Carabell v. United States,” p. 1, (June 5, 2007) available 

at http://www.epa.gov/owow/wetlands/pdf/RapanosGuidance6507.pdf
Clean Water Rule Response to Comments – Topic 8: Tributaries

580

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. The final rule clearly 

requires the presence of both bed and banks and another indicator of OHWM, if 

one is not present then the water does not qualify as a tributary. Wetlands, lakes, 

ponds, and other features lacking a bed and banks and/or OHWM are no longer 

defined as tributaries in the Final Rule, but may be considered jurisdictional 

“waters of the United States” as adjacent waters or similarly situated waters with a

significant nexus to (a)(1) through (3) waters. For further discussion see summary 

response 8.1. 

NRG Energy, Inc. (Doc. #13995)

8.488 Because tributaries would always be considered jurisdictional under the proposed rule, 

NRG believes that the inclusion of specific language in the rule supporting continuation 

of the waste treatment system exclusion, as well as other "waters" formally excluded 

from the definition of “Waters of the U.S.", is necessary.

As such, NRG requests that the above final sentence from the "tributary" definition 

be revised as follows:

"A tributary, including wetlands, can be a natural, man-altered, or manmade 

water and includes waters such as rivers, streams, lakes, ponds, impoundments, 

canals and ditches not excluded in paragraph (t)O), (2 ), (3). (4J or (5) of this 

section." (p. 4)

Agency Response: The final rule provides additional clarity by specifically 

identifying waters that are excluded from the definition of waters of the U.S. in 

(b)(1)-(7). See summary responses in section 7 for the specifics of each type of 

excluded feature. 

Todd Wilkinson (Doc. #13443)

8.489 The rule and the definition of "ephemeral" streams would now include streams that do 

not typically flow. In fact areas that may only flow after heavy rains once every few years 

would now be Waters of the U.S. Expanding regulations to ephemeral streams is a clear 

expansion. As proposed the definition used in the rule can be used in conjunction with 

one another so that if an area isn't a water body it may be a tributary. If it is isolated and 

does not contribute direct flow, flow might still be indirect, the shallow subsurface water 

beneath it may be connected to a water body, or it might be in a floodplain, riparian area 

or watershed and become significant when combined. This conjunctive definitional

interpretation will make it virtually impossible for landowners to determine if their land 

is jurisdictional under the revised WOTUS definition. (p. 1 - 2)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. The final rule clearly 

requires the presence of both bed and banks and another indicator of OHWM, if 

one is not present then the water does not qualify as a tributary. Wetlands, lakes, 

ponds, and other features lacking a bed and banks and/or OHWM are no longer 

defined as tributaries in the Final Rule, but may be considered jurisdictional 

“waters of the United States” as adjacent waters or similarly situated waters with a 
Clean Water Rule Response to Comments – Topic 8: Tributaries

581

significant nexus to (a)(1) through (3) waters. Dry lands have not historically nor 

are now waters of the U.S. For further discussion of the historic and current extent 

of jurisdiction in relation to ephemeral streams see summary response 8.1.1. 

Newmont Mining Corporation (Doc. #13596)

8.490 Many Ephemeral and Intermittent Drainages Could Be Deemed “Tributaries”: It is highly 

questionable, to say the least, whether ephemeral and intermittent drainages in the arid 

and semi-arid West that flow for at most a few days or weeks every year or every few 

years, and where the flow may reach a TNW or a tributary thereof once every decade, 

have or could have any impact on a TNW located scores of miles away, let alone a 

significant impact. As the WAC comments show, the Agencies lack any sound scientific 

basis for concluding that such drainages could have any such significant adverse impact 

on a TNW. Nonetheless, under the Proposal, it appears that all such ephemeral and 

intermittent drainages would be deemed “tributaries” and therefore per se jurisdictional if 

they physically connect with, and contribute even one drop of surface flow to, a TNW or 

its major tributaries. Thus, the Proposal defines the term “tributary” to mean any “water 

physically characterized by the presence of a bed and banks and ordinary high water 

mark” and “which contributes flow, either directly or through another water,” to a TNW. 

See, e.g., paragraph (c)(5) at 79 Fed. Reg. 22263. Moreover, a “tributary” as so defined 

does not lose its status as a tributary if, for any length, there are one or more natural 

breaks (such as a stream that flows underground) so long as a bed and banks and an 

ordinary high water mark can be identified upstream of the break. Id. 

In Newmont’s meetings with Corps and EPA officials, those officials stated that 

ephemeral and intermittent drainages are jurisdictional under the Proposal, regardless of 

how infrequently flow is actually observed from the drainage to a seasonal or perennial 

stream (even if only once every decade or several decades), so long as the drainage has a 

bed and banks and an ordinary high water mark, and it physically connects (without 

losing its channel definition) to a TNW or tributary to a TNW. EPA and Corps officials 

were adamant that the bed, banks, and ordinary high water mark are physical 

manifestations that the drainage has a high enough volume, frequency, and duration of 

flow that it “contributes flow” to a TNW or tributary system. See also, 79 Fed. Reg. 

22202 (stating these features “generally are physical indicators of water flow”). Thus, in 

the Agencies’ view, regulators need not demonstrate that an ephemeral or intermittent 

drainage actually “contributes flow” – even one drop of water – to a TNW to be 

considered a jurisdictional “tributary”; rather, so long as the drainage has the physical 

characteristics defined by the Agencies as indicating flow, and the drainage channel 

connects by surface to a TNW or a tributary of a TNW, it is per se jurisdictional. This 

approach fails to conform with the morphogenesis of certain features in the Great Basin, 

where some drainages are established during very rare (hundreds of years) extreme 

precipitation events. 

The Agencies’ assertion of jurisdiction over all such “tributaries” is a reversal of the 

position taken in the 2008 Guidance, and is directly contrary to Justice Kennedy’s 

“significant nexus” test set forth in the Rapanos decision. It is also contrary to the 

Rapanos plurality’s concept of a “tributary,” which requires that streams flow 

continuously at least seasonally to be considered per se jurisdictional. In Newmont’s
Clean Water Rule Response to Comments – Topic 8: Tributaries

582

view, the Agencies’ position in the 2008 Guidance that only “relatively permanent” 

tributaries are per se jurisdictional is reasonable, while the definition of a tributary in the 

Proposal is not. Drainages that rarely flow, and in particular ephemeral or intermittent 

drainages that flow once every decade or so, cannot rationally be said to affect in all 

cases, much less to significantly affect, the chemical, physical, or biological integrity of a 

downstream TNW, which in the arid/semi-arid West would be many, many miles away. 

To the extent the Agencies are relying on the U.S. EPA Draft Report: “Connectivity of 

Streams and Wetlands to Downstream Waters: A Review and Synthesis of Scientific 

Evidence” (Docket No. EPA-HQ-OA-2013-0582 (November 6, 2013)) to support the 

proposed definition of “tributary,” Newmont notes that, as explained in the WAC 

comments, the science underlying this Report deals mostly with areas of the U.S. where 

ephemeral and intermittent drainages do experience significant flows on an annual basis, 

not with the arid/semiarid West. 

As such, and as we discuss more fully below, we believe that the Agencies must, at a 

minimum, exclude ephemeral and intermittent drainages from the category of per se 

jurisdictional waters and include flow volume and duration requirements when 

determining on a case-by-case basis the jurisdictional status of particular ephemeral and 

intermittent drainages. Absent such changes to the Proposal, there is a significant chance 

that many ephemeral and intermittent drainages on Newmont’s properties that no 

regulator would ever heretofore have considered as even potentially jurisdictional 

(because their flow is so small that they could not, under any stretch of the imagination, 

significantly affect a downstream TNW), might now be regulated as “tributaries.” (p. 29-

32)

Agency Response: See summary response 8.1 and 8.1.1. and responses in TSD and 

elsewhere that explain the legal and technical basis for the definition of tributary.

Southern Environmental Law Center et al. (Doc. #13610)

8.491 If a water is outside the floodplain and riparian areas, the Corps should be able to use best 

professional judgment to claim the water as jurisdictional as long as there is a chemical, 

physical, or biological connection. (p. 44)

Agency Response: See TSD section 8.B. 

D. Fleming (Doc. #13654)

8.492 Ordinary High Water

The definition of a tributary is based on having a bed and bank plus an ordinary high 

water mark. On ephemeral channels there is rarely water in the channel so an ordinary 

high water mark is usually speculation. This matter is so confusing to Corps staff that the 

determination of ordinary high water is buried somewhere in regulatory guidance letters. 

By current interpretation a 1 ft. wide and 1 ft. deep channel is considered waters of the 

United States by regulators, but what citizen would believe that the federal government 

claims jurisdiction to such a small featured. Since the ordinary high water mark is so 

important on determining if a channel is considered waters of the US that this definition 

should be open for public comment and peer review. (p. 1 – 2)
Clean Water Rule Response to Comments – Topic 8: Tributaries

583

Agency Response: The final rule clearly requires the presence of both bed and 

banks and another indicator of OHWM, if one is not present then the water does

not qualify as a tributary. Ephemeral streams have historically been regulated 

under the CWA and OHWM has been identified and used to determine the lateral 

extent of jurisdiction in these ephemeral streams. See summary response to 

comments 8.1.2 for further explanation. 

8.493 Tributary Definition

We object to the definition of a tributary as it extends definition of waters of the US 

upstream to erosional features, and stretches of a channel that are merely short term 

conduits for surface water that have no significant nexus to downstream water quality. 

(p. 2)

Agency Response: See summary response 8.1. and responses that distinguish 

landscape features like gullies and rills.

Tamara Choat (Doc. #13701)

8.494 If the proposed rule cannot be dropped, the following concerns and recommendations 

should be addressed.

1. Remove the expansion of the Clean Water Act to intermittent and ephemeral nonnavigable streams, which are defined as tributaries and per se jurisdictional under 

the proposed rule.

2. Remove the inclusion of ditches in the definition of tributary. (p. 1)

Agency Response: Waters of the U.S. has historically included intermittent and 

ephemeral streams and some ditches. The final rule clarifies the extent of 

tributaries by adding additional context and field indicators to the definition and 

specifically identifying the features that excluded from the definition of waters of the

U.S in (b)(1) – (7). See summary response 8.1 for further discussion of the definition 

of tributaries and 8.1.1 for the relevance of flow regime. 

8.495 Air emissions from industrial plants - In recent years, EPA has argued that a point source 

discharge occurs under the Clean Water Act when an industrial plant or other facility 

vents or emits dust or other materials to the ground outside, where they are carried by 

rainfall or snow runoff into jurisdictional waters. In EPA’s view, the facility (which is 

itself the point source) makes a regulated discharge when it exhausts dust or other 

airborne materials from an enclosed facility to the ground where rainwater carries it to 

receiving waters. Under the proposed rule, in many cases EPA would not even need to 

show that stormwater has carried materials to a current WOTUS. Instead, by regulating 

parts of the facility grounds as ephemeral tributaries or adjacent waters, the agency may 

claim an unlawful discharge simply by showing that air emissions have been deposited to

the on-site features themselves. (p. 22)

Agency Response: The definition of discharge and point source are outside the 

scope of this rule and a case specific analysis of permitting requirements of a facility 

are also outside the scope of this rulemaking effort. The exclusion of certain 

stormwater features from the definition of waters of the U.S. is discussed in the 

summary response 7.4.4.
Clean Water Rule Response to Comments – Topic 8: Tributaries

584

8.496 “Tributary”

The Agencies’ proposed definition of “tributary” is extraordinarily vague and overbroad. 

The definition would cover just about anything that conveys water and is not otherwise 

ruled out by narrow exclusions. A “tributary”:

 Need only demonstrate the bare minimum evidence of a water’s flow through any 

channel, a bed, bank and ordinary high water mark;

 Can be anything that “contributes” even the tiniest amount of water;

 May only “contribute” water infrequently, e.g., during rare, extreme precipitation 

events;

 May only contribute water to major waters by an “indirect” route through another 

“water,” which in turn also could convey only small, infrequent flows via indirect 

routes; and

 Can include even “upland” ditches, if they include areas that can be characterized 

as “wetland” anywhere along their entire length, or if they occasionally receive 

stormwater overflow from any “wetland” or other water.

In essence, the definition of “tributary” will cover virtually anything (not explicitly 

excluded) where water flows enough to make a mark (ordinary high water mark, which 

can be nothing more than disturbed vegetation or soil) that is capable of “contributing” 

any amount of flow (even a trickle) to a downstream location that eventually connects to 

larger water bodies.

Is a ditch a “tributary”? In most cases, yes. This rulemaking is the first time the Agencies’ 

have specifically included ditches within the definition of “tributary.” Like many other 

aspects of the proposal, however, the jurisdictional coverage of ditches is unclear. The 

proposal provides, in part, that: “[a] tributary ... includes water such as rivers, streams, 

lakes, ponds, impoundments, canals, and ditches not excluded in paragraphs (b)(3) or (4) 

of this section.” 79 Fed. Reg. 22,207. Most industrial, municipal, and agricultural ditches 

will not be excavated wholly in uplands, drain only uplands, and have less than perennial 

flow. Most ditches will also eventually contribute some sort of flow to larger waters. This 

is precisely why ditches exist in the first place—to carry water away, Therefore, most 

ditches will meet the definition of a tributary and would not be excluded from CWA 

permitting requirements. (p. 27 – 28)

Agency Response: Waters of the U.S. has historically included intermittent and 

ephemeral streams and some ditches. The final rule clarifies the extent of 

tributaries by adding additional context and field indicators to the definition and 

specifically identifying the features that excluded from the definition of waters of the 

U.S in (b)(1) – (7). See summary response 8.1 for further discussion of the definition 

of tributaries and 8.1.1 for the relevance of flow regime. See summary response 6.2 

for excluded ditches.

Big Horn County State of Wyoming (Doc. #14571)

8.497 The proposed rule includes expansive new definitions of tributaries, neighboring, and 

adjacent waters. These definitions are crucial to the implementation of the proposed rule, 
Clean Water Rule Response to Comments – Topic 8: Tributaries

585

and will be covered below for their potential impact on Big Horn County. However, the 

proposed rule explicitly reads that waters which qualify under these new definitions 

would be jurisdictional waters of the United States, by rule no additional analysis would 

be required. Such a blanket declaration of jurisdictional authority establishes a 

presumption that every stream, dry creek bed and ditch not explicitly exempted by the 

rule (another area of significant confusion) is automatically a water of the U.S. even if it 

cannot be immediately determined to meet the new qualifications of jurisdictional water. 

(p. 3)

Agency Response: The final rule clarifies the extent of tributaries by adding 

additional context and field indicators to the definition and specifically identifying 

the features that excluded from the definition of waters of the U.S in (b)(1) – (7). 

See summary response 8.1 for further discussion of the definition of tributaries and 

8.1.1 for the relevance of flow regime. See summary response 6.2 for excluded 

ditches.

Waters of the United States Coalition (Doc. #14589)

8.498 [T]he proposed changes to the definitions of “adjacent waters” and “neighboring” will 

reach numerous waters that were previously outside the jurisdiction of the Clean Water 

Act. We request that ACOE’s jurisdiction be limited to the ordinary high water mark 

(“OHWM”) of traditional navigable waters and natural streams tributary thereto. A broad 

definition that covers multiple types of features that may or may not have an OHWM will 

only create confusion. The rule notes that uplands within floodplains are never waters of 

the U.S., but without requiring the physical presence of a defined OHWM, jurisdictional 

areas could easily be expanded. (p. 15)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. The final rule clearly 

requires the presence of both bed and banks and another indicator of OHWM, if 

one is not present then the water does not qualify as a tributary. Wetlands, lakes, 

ponds, and other features lacking a bed and banks and/or OHWM are no longer 

defined as tributaries in the Final Rule, but may be considered jurisdictional 

“waters of the United States” as adjacent waters or similarly situated waters with a 

significant nexus to (a)(1) through (3) waters. Dry lands have not historically nor 

are now waters of the U.S. 

The Clean Energy Group Waters Initiative (Doc. #14616)

8.499 [T]he proposed definitions of tributary should be revised as follows to make clear that the 

wastewater treatment exclusion applies regardless of other aspects of the rule, with 

additions in underlined bold and deletions shown in strikethrough:

601602

 

601 Additionally, please see recommended language in the following section regarding a distinct exemption or 

exclusion for reserve cooling water impoundments, canals, and water conveyances, which are not traditionally 

considered part of a waste treatment system but also should not be considered WOTUS.

602 Our proposed revisions include additional changes to the definition of “tributary” that are addressed later in these 

comments.
Clean Water Rule Response to Comments – Topic 8: Tributaries

586

(5) Tributary. The term tributary means a water physically characterized by the presence 

of a bed and banks and ordinary high water mark, as defined at 33 CFR 328.3(e), which 

contributes flow, either directly or through another water, to a water identified in 

paragraphs (a)(1) through (4) of this section provided that hydric soils or hydrophytic 

vegetation are present. In addition, wetlands, lakes, and ponds are tributaries (even if 

they lack a bed and banks or ordinary high water mark) if they contribute flow, either 

directly or through another water to a water identified in paragraphs (a)(1) through (3) of 

this section provided that hydric soils or hydrophytic vegetation are present. A water 

that otherwise qualifies as a tributary under this definition does not lose its status as a 

tributary if, for any length, there are one or more man-made breaks (such as bridges, 

culverts, pipes, or dams), or one or more natural breaks (such as wetlands at the head of 

or along the run of a stream, debris piles, boulder fields, or a stream that flows 

underground) so long as a bed and banks and an ordinary high water mark can be 

identified upstream of the break. However, these interrupted portions are not 

considered a jurisdictional tributary. A tributary, including wetlands, can be a natural, 

man-altered, or man-made water and includes waters such as rivers, streams, lakes, 

ponds, impoundments, canals, and ditches not excluded in paragraph (b)(1),(3), or (4) or 

(6) of this section. Man-made structures with engineered bed, banks and top of 

banks that are not created from jurisdictional waters or whose construction predates the Clean Water Act are not considered a jurisdictional tributary. (p. 6)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. The final rule clearly 

requires the presence of both bed and banks and another indicator of OHWM, if 

one is not present then the water does not qualify as a tributary. Wetlands, lakes, 

ponds, and other features lacking a bed and banks and/or OHWM are no longer 

defined as tributaries in the Final Rule, but may be considered jurisdictional 

“waters of the United States” as adjacent waters or similarly situated waters with a 

significant nexus to (a)(1) through (3) waters. The agencies will continue to assert 

jurisdiction over manmade and man-altered waters which fit under the definition of 

tributary, unless specifically excluded in (b)(1)-(7). The agencies did not add a 

requirement for hydric soils or hydrophytic vegetation for (a)(1) through (a)(4) 

waters to server as a connection in the tributary network as suggested in the 

comment above, such a restriction is not supported by the science. The Connectivity 

Report and agency experience support the treatment of manmade and man-altered 

systems as laid out in the final rule, for further discussion see the TSD. 

State of Oklahoma (Doc. #14773)

8.500 I also disagree with the determination that ephemeral streams should be subject to the 

proposed WOTUS rule. Similar to the floodplain definition, the ephemeral definition 

provided in the proposed WOTUS rule is inconsistent with Oklahoma's definition of 

ephemeral streams in our water quality standards. These differing definitions are 

examples of the confusion created by the proposed WOTUS rule and would add an 

additional burden on landowners, developers and other stakeholders who will be required 

to operate between conflicting technologies. (p. 2)
Clean Water Rule Response to Comments – Topic 8: Tributaries

587

Agency Response: See summary response 8.1 for further discussion of the 

definition of tributaries and 8.1.1 for the relevance of flow regime.

Patti Buck (Doc. #14825)

8.501 As an example, you now have included my agricultural ditches into the category of 

“tributaries?” This is inappropriate. The two exclusions you have provided for ditches are 

not adequate to alleviate the enormous burden you just placed on the entire agriculture

community. “Ditches” should not be waters of the U.S. Farm ponds should not be waters 

of the U.S. Dry washes, dry streambeds, and ephemeral streams should not be waters of 

the U.S. (p. 1)

Agency Response: See summary response 8.1 for discussion of the definition of 

tributaries and 8.1.1 for the relevance of flow regime. See summary response 6.2 for 

excluded ditches.

Clean Water Action (Doc. #15015)

8.502 We strongly support the Agencies’ proposal to categorically include all tributaries, 

regardless of size or frequency of flow, within the jurisdiction of the Clean Water 

Act. Tributaries have a direct impact on the physical, chemical and biological integrity of 

downstream waters, and this decision is grounded in the best available peer-reviewed 

science, as summarized in EPA’s draft Connectivity of Streams and Wetlands to 

Downstream Waters, which is a synthesis of over 1,000 peer-reviewed studies. This 

determination has also been found to be scientifically sound by the Science Advisory 

Board (SAB) panel that reviewed the proposed rule.603

Headwater streams provide most of the flow to downstream streams and rivers. 

Intermittent and ephemeral streams may only flow during parts of the year, but they 

support water quality in downstream waters by filtering pollutants and capturing 

nutrients. Headwaters and intermittent and ephemeral tributaries make up 60 percent of 

the stream miles in the continental U.S.604 Indeed, scientists have discovered that even 

when streams lack surface flows, they are “critical conduits for water, energy, material, 

and organisms” and “shallow subsurface flows may often connect dry parts of a stream or 

river,” thus providing critical water supply to downstream perennial streams or rivers.605 

Headwater and seasonal streams also feed the drinking water sources of 117 million 

Americans606. Clarifying that all tributary streams, regardless of size or frequency of 

flow, are covered under the CWA will restore protections to hundreds of thousands of 

miles of streams that one in three Americans depend on for drinking water.607 (p. 2 – 3)

 

603 U.S. EPA Science Advisory Board, Science Advisory Board (SAB) Consideration of the Adequacy of the 

Scientific and Technical Basis of the EPA’s Proposed Rule titled “Definition of Waters of the United States under 

the Clean Water Act,” EPA-SAB-14-007, (Sept. 30, 2014) (hereinafter “SAB Rule Review Letter”), available at 

http://yosemite.epa.

604 http://water.epa.gov/type/rsl/streams.cfm

605 Acuna, et al, “Why Should We Care About Temporary Waterways?” Science Vol. 343 (March 7, 2014)

606 http://water.epa.gov/lawsregs/guidance/wetlands/surface_drinking_water_index.cfm , Last accessed November 

12, 2014.

607 Id.
Clean Water Rule Response to Comments – Topic 8: Tributaries

588

Agency Response: See summary response 8.1 for discussion of the definition of 

tributaries and 8.1.1 for the relevance of flow regime. 

8.503 We recommend that the definition of “tributaries” be broadened to ensure that all 

tributaries across a range of regional and climatic variations are categorically 

protected under the CWA. Under the current proposal, a tributary must possess an 

ordinary high water mark (OHWM) to be considered jurisdictional, even though the 

agencies acknowledge in the preamble for the rule that in low-gradient and arid regions 

the presence of an OHWM or even bed and bank may be discontinuous or difficult to 

observe.608 Ephemeral streams and even some intermittent streams frequently lack an 

obvious OHWM because “the climate of the region drastically influences the hydrology, 

channel-forming processes, and distribution of OHWM indicators such that delineations 

can be inconsistent and problematic.”609 Even in non-arid regions, Army Corps of 

Engineers staff have found delineating non-perennial streams relying solely on the 

presence of an OHWM to be a challenge.610

Intermittent and ephemeral streams account for over 60% of the stream miles in the 

continental United States.611 In arid and semi-arid states like Arizona, New Mexico, 

Nevada, Utah, Colorado and California over 81% of streams are classified as ephemeral 

or intermittent.612 These seasonal and rain dependent streams feed our nation’s public 

drinking water sources, and not just in states like Arizona where they account for 79% of 

drinking water sources, but even in non-arid states like Arkansas they account for 65% of 

the stream miles in Source Water Protection Areas.613 Nationally, intermittent and 

ephemeral streams account for 58% of the total stream miles in Source Water Protection 

Areas.614 It is imperative that the definition of tributaries be written broadly enough so it 

is clear that all tributaries in Source Water Protection Areas are protected by the CWA, 

regardless of whether or not they possess an identifiable OHWM.

Our concern about this narrow legal definition of tributaries is shared both by members of 

the SAB panel that reviewed the proposed rule and by other experts on stream ecology.615

The SAB panel suggested that the agencies change the wording of the definition of 

tributaries to “bed, bank and other evidence of flow” and not have the presence of an 

 

608 Fed. Reg. 79 at 22202 (April 21, 2014)

609

http://www.spk.usace.army.mil/Portals/12/documents/regulatory/pdf/Ordinary_High_Watermark_Manual_Aug_200

8.pdf at 1. Last accessed November 12, 2014.

610 http://www.usace.army.mil/Portals/2/docs/civilworks/regulatory/reg_supp/west_mt_finalsupp_aug2014.pdf

Last accessed November 14, 2014.

611 http://water.epa.gov/type/rsl/streams.cfm

612 Levick, L., J. Fonseca, D. Goodrich, M. Hernandez, D. Semmens, J. Stromberg, R. Leidy, M. Scianni, D. P. 

Guertin, M. Tluczek, and W. Kepner. 2008. The Ecological and Hydrological Significance of Ephemeral and 

Intermittent Streams in the Arid and Semi-arid American Southwest. U.S. Environmental Protection Agency and 

USDA/ARS Southwest Watershed Research Center, EPA/600/R-08/134, ARS/233046

613 http://water.epa.gov/lawsregs/guidance/wetlands/surface_drinking_water_index.cfm Last accessed November 12, 

2014.

614 Id.

615 SAB Rule Review Letter at 2; Acuna, et al, “Why Should We Care About Temporary Waterways?” Science Vol. 

343 (March 7, 2014)
Clean Water Rule Response to Comments – Topic 8: Tributaries

589

order high water mark (OHWM) be a required attribute for a stream to be considered a 

jurisdictional tributary under the CWA.616

Acuna, et al (2014) recommend an even boarder definition that would ensure “temporary 

waterways” (which include ephemeral streams) are legally defined as “waters of the 

U.S.” - if “(i) they flow at some times and this flow connects them to a river network, or 

(ii) if they are habitat for obligate aquatic organisms or terrestrial organisms unique to dry 

river beds.”617

Broadening the legal definition of tributaries is critical, because as the proposal is 

currently written, only streams that meet the definition of “tributaries” will be 

categorically protected under the CWA. As our water resources deal with additional 

stressors brought on by climate change, it will become even more urgent for all seasonal 

and rain dependent streams to be afforded strong and clear protections. In certain regions 

of the country scientists have already observed historically perennially flowing streams 

shifting to temporarily flowing streams due to climate change or over extraction of 

water.618 (p. 3 - 4)

Agency Response: See summary responses 8.1 and 8.1.2. 

The Heritage Foundation (Doc. #15055)

8.504 All Tributaries are not “Waters of the United States”

In the proposed rule, the agencies conclude that all tributaries should be per se “Waters of 

the United States” (or categorically jurisdictional). The agencies point to Justice 

Kennedy’s concurrence in Rapanos:

While Justice Kennedy focused on adjacent wetlands in light of the facts of the 

cases before him, it is reasonable to utilize the same standard for tributaries. As 

discussed in this preamble, based on a detailed examination of the scientific 

literature, the agencies conclude that tributaries as they propose to define them 

perform the requisite functions identified by Justice Kennedy for them to be 

considered, as a category, to be “Waters of the United States.”619

The agencies are acknowledging that Justice Kennedy was solely “focused on adjacent 

wetlands,” but are still trying to cover additional waters. The EPA and Corps are 

justifying this extreme overreach based on the science, yet ironically, the agencies have 

not even waited for the final scientific report before taking such an action.

Further, quite simply, it is unreasonable to utilize this same standard for tributaries. 

There is no indication in Rapanos that Justice Kennedy supported such broad coverage of 

the law. In fact, the opposite is true. 

 

616 SAB Rule Review Letter at 2.

617 Acuna, et al, “Why Should We Care About Temporary Waterways?” Science Vol. 343 (March 7, 2014)

618 Id.

619 Federal Register, Vol.79, No. 76 (April 21, 2014), p. 22204.
Clean Water Rule Response to Comments – Topic 8: Tributaries

590

He makes it clear that at least some tributaries should not be categorically jurisdictional. 

For example, when analyzing whether wetlands adjacent to tributaries should be 

jurisdictional, he explains:

Yet the breadth of this standard – which seems to leave wide room for regulation 

of drains, ditches, and streams remote from any navigable-in-fact water and 

carting only minor water volumes towards it – precludes its adoption as the 

determinative measure of whether adjacent wetlands are likely to play an 

important role in the integrity of an aquatic system comprising navigable waters 

as traditionally understood.620

Under the proposed definition of tributary, these types of waters (“drains, ditches...”) 

would be covered. Justice Kennedy was concerned about the regulation of the very 

waters that the agencies now want to make categorically jurisdictional. (p. 3 – 4)

Agency Response: See summary response 8.1 and the TSD and Agency responses 

explaining the legal basis of the rule in light of relevant court cases. 

Lea Soil and Conservation District Board of Supervisors (Doc. #15144.1)

8.505 Section (a)(5) and definition of “tributary”: For legal and scientific clarity, the agencies 

should withdraw the Proposed Rule and replace it with a rule that defines tributaries as 

only those waters that maintain a permanent, surface water connection to an (a)(1) or 

(a)(3) water. (p. 3)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. The final rule clearly 

requires the presence of both bed and banks and another indicator of OHWM, if 

one is not present then the water does not qualify as a tributary. Wetlands, lakes, 

ponds, and other features lacking a bed and banks and/or OHWM are no longer 

defined as tributaries in the Final Rule, but may be considered jurisdictional 

“waters of the United States” as adjacent waters or similarly situated waters with a 

significant nexus to (a)(1) through (3) waters. For further discussion of the 

definition of tributary see summary response 8.1. 

8.506 Specific comment was requested concerning whether in-channel “wetlands” should be 

included with tributaries or adjacent waters. Logically, they seem better positioned in the 

realm of adjacent waters. Placing them in the category of tributaries runs contrary to that 

definition’s requirements for a bed, banks and an ordinary high water mark. (p. 8)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. The final rule clearly 

requires the presence of both bed and banks and another indicator of OHWM, if 

one is not present then the water does not qualify as a tributary. Wetlands, lakes, 

ponds, and other features lacking a bed and banks and/or OHWM are no longer 

defined as tributaries in the Final Rule, but may be considered jurisdictional 

“waters of the United States” as adjacent waters or similarly situated waters with a 

significant nexus to (a)(1) through (3) waters. 

 

620 Rapanos v. U.S., 547 U.S. 715, 767. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

591

Arizona Department of Transportation (Doc. #15215)

8.507 ADOT agrees with the need to clarify the definition of waters regulated under the Clean 

Water Act and appreciates the use of a rulemaking to provide that clarification. In 

addition, ADOT understands that the EPA and the Corps have emphasized that the intent 

of the rule is not to expand the Corps' jurisdiction under the Clean Water Act. However, 

despite this intent, without further clarification, the Proposed Rule as written could 

expand the Corps' jurisdiction. The confusion is primarily caused through the proposed 

definition of "tributary.' The proposed definition of "tributary" states: "The term tributary 

means a water physically characterized by the presence of a bed and banks and ordinary 

high water mark, as defined at 33 CFR 328.3(e), which contributes flow, either directly or 

through another water, to a water identified in paragraphs (a)(l) through (4) of this 

section.” The proposed rule also states that gullies, rills, and non-wetland swales are 

exempt from regulation. The EPA and Corps acknowledge in Part Ill. F. 2, of the 

preamble that rills, gullies, and non-wetland swales may contribute flow to a tributary 

with steep side slopes. Gullies and rills are further defined in Part Ill. 1, including gullies 

that are commonly found in areas of low density vegetative cover or with soils that are 

highly erodible and are younger than streams in geologic age, and that rills are formed by 

overland water flows. This section also states that both rills and gullies typically lack an 

Ordinary High Water Mark (OHWM). The December 2, 2008 Corps/EPA guidance 

memorandum excluded swales or erosional features (including gullies, small washes 

characterized by low volume, infrequent, or short duration flow). Overall, ADOT feels 

that the proposed definitions do not provide enough clarification of what constitutes a 

small tributary compared to a rill or gully, and the determination of the presence or 

absence of an OHWM can be subjective (see Photo 1, below). In addition, the exemption 

of small washes from the 2008 guidance is lost in the proposed rule. The arid west 

landscape is covered with small drainages and under the proposed rule it is unclear when 

an erosional feature (such as a rill or gully) would be considered to be a tributary by the 

Corps.

(p. 1 – 2)
Clean Water Rule Response to Comments – Topic 8: Tributaries

592

Agency Response: See summary response at 8.1 for definition of tributary, 8.1.2 

for efforts to improve OHWM determination especially arid regions, and 7.3.7 for 

discussion of gullies and rills. 

Southern Ute Indian Tribe Growth Fund (Doc. #15386)

8.508 The Proposed Rule should be modified to identify tributaries that have a 'relatively 

permanent flow,' meaning that they 'typically flow year-round or have continuous flow 

for at least 90 days' are jurisdictional by rule. If relatively permanent flow is not found, 

tributaries should be evaluated on a case specific basis to determine if the tributary has a 

significant nexus to a water identified in sections (a)(1) through (3) of this Proposed 

Rule. A definition of relatively permanent flow should also be added to the rule. (p. 6)

Agency Response: See summary response 8.1.1. 

8.509 Wetlands that connect jurisdictional tributary segments should be excluded from the 

definition of "tributary" because they generally lack a defined bed, bank, and OHWM. 

These types of wetlands should be considered an adjacent water and thus remain 

jurisdictional. (p. 7)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. The final rule clearly 

requires the presence of both bed and banks and another indicator of OHWM, if 

one is not present then the water does not qualify as a tributary. Wetlands, lakes, 

ponds, and other features lacking a bed and banks and/or OHWM are no longer 

defined as tributaries in the Final Rule, but may be considered jurisdictional 

“waters of the United States” as adjacent waters or similarly situated waters with a 

significant nexus to (a)(1) through (3) waters.

Wyoming County Commissioners Association (Doc. #15434)

8.510 As noted by the Congressional Research Service, the rule defines tributary for the first 

time and does so "broadly." The WCCA objects to this expansive definition that 

automatically declares a tributary a water of the U.S. even if it only sometimes 

contributes flow to another water that only sometimes contributes flow to still another 

water, and on and on until eventually the flow drains into a currently jurisdictional water. 

At best, when combined with the terms "adjacent," "neighboring," and excluded 

"ditches," the definition provides no certainty to Wyoming's counties or their constituents 

about what is considered jurisdictional waters, even when they flow for only very brief 

periods. At worst, when taken in the context of the recently released and aforementioned 

USGS maps , the definition could be construed to wrest jurisdictional control of all of 

Wyoming's approximately 270,000 miles of streams, over 80% of which are intermittent 

or ephemeral. In response to requests from the House Committee on Science, Space and 

Technology, the EPA insists that the USGS maps have not been used for regulatory 

purposes, and further, that the "EPA is not aware of maps prepared by any agency, 

including the EPA, of waters that are currently jurisdictional under the CWA or that 

would be jurisdictional under the proposed rule." 

The EPA's response poses two related problems. First, given the domino effect of the 

tributary definition, the USGS maps illustrate the potential reach of the proposed rule 
Clean Water Rule Response to Comments – Topic 8: Tributaries

593

regardless of the EPA's use of the maps to date. As a headwaters state, Wyoming is 

particularly sensitive to the discussion of headwaters in the proposed rule (see the 

Sublette County discussion above and the Park County discussion below). The EPA 

repeatedly argues that headwaters are particularly important to regulate because of their 

effects on downstream, jurisdictional waters , even if the headwaters are intermittent, 

ephemeral, or are a "substantial distance from the nearest [jurisdictional water]. The 

EPA claims that no case-specific analysis is necessary on these often dry creek beds 

because "tributaries, including headwaters, intermittent, and ephemeral streams, and 

especially when all tributaries in a watershed are considered in combination, have a 

significant nexus to traditional navigable waters (emphasis added) Despite the EPA's 

claims of a limiting rule, it is difficult for a reasoned observer to not view these 

statements in plain writing as a dramatic and unprecedented grab for federal authority. 

The second problem posed by the EPA's response to the House Committee on Science, 

Space, and Technology is that if the USGS maps have not been used as EPA claims, and 

if no such maps exist in any agency, then clarity as to what is a tributary and what is not 

simply cannot be offered by the EPA, USACE or any other agency. No baseline data 

exists, and no map exists to show potential impacts. (p. 5-6)

Agency Response: Waters of the U.S. has historically included intermittent and 

ephemeral streams and some ditches. The final rule clarifies the extent of 

tributaries by adding additional context and field indicators to the definition and 

specifically identifying the features that excluded from the definition of waters of the 

U.S in (b)(1) – (7). See summary response 8.1 for further discussion of the definition 

of tributaries and 8.1.1 for the relevance of flow regime. See summary response 6.2 

for excluded ditches. Determinations of jurisdiction are done on a case by case basis 

based on the best information available and they are only valid for five years 

because environmental conditions which can shape the outcome can change over 

time. For example changes in ground and surface water levels due to changes in 

water usage and losses through evapotranspiration. While maps of all the 

jurisdictional or non-jurisdictional waters are not feasible, the agencies have 

provided clarity in terms of the identifying features and analysis required to 

determine the jurisdictional status of a given waterbody. 

Pennsylvania Farm Bureau (Doc. #15508)

8.511 Furthermore, “ordinary high water mark” is a term that encompasses any physical sign of 

water flow, such as changes in the soil, vegetation or debris. When rainwater flows 

through any path on the land, it tends to leave some sort of mark, even if flows are 

infrequent. EPA and ACOE themselves recognize that the definition of OHWM is vague, 

ambiguous and inconsistently applied. In fact, in its comments, AFBF noted that an 

official from the ACOE Philadelphia District has observed that, due to inconsistent 

interpretations of the OHWM concept, as well as inconsistent field indicators and 

delineation practices, identifying precisely where the OHWM ends is simply a matter of 

judgment, so reliance on this term provides neither certainty nor clarity. Moreover, 

ACOE is reportedly in the process of redefining how it determines an OHWM, yet 

nowhere in the proposal do the agencies signal to the public that this behind-the-scenes 

change is occurring, placing a key term in the proposed rule beyond public comment. (p. 

9)
Clean Water Rule Response to Comments – Topic 8: Tributaries

594

Agency Response: The final rule continues the longstanding practice of using the 

OHWM to determine the lateral extent of jurisdiction for tributaries. Where the 

physical characteristics of bed and banks and another indicator of ordinary high 

water mark no longer exist or are actively manipulated, the presence of bed and 

banks and OHWM may be determined by using other appropriate means that 

consider the characteristics of the surrounding areas. The OHWM continues to be 

identified using indicators of regular high flows whose return interval varies across 

the country based on climate, hydrology, and other factors. The agencies plan to 

continue to build on the more than a decade of effort spent improving the 

consistency and rigor of OHWM identifications, especially in the western US where 

two guidebooks for OHWM identification have already been developed, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates.

Countrymark Cooperative Holding Corporation, LLC; Countrymark Refining and Logistics, 

LLC (Doc. #15656)

8.512 Provide clear definitions of "rill," "gully," and "swale," that exclude from federal 

jurisdiction any erosion feature on the land caused by water runoff, whether or not an 

Agency official believes they can discern a bed, bank or ordinary high water mark. (p. 4)

Agency Response: See summary response at 7.3.7. 

8.513 Nothing in the current regulation includes ephemeral streams and EPA and the Corps did 

not consistently consider ephemeral streams to be tributaries until 2000, when the 

preamble to the Corps Nationwide Permits preamble specified that jurisdiction extends to 

ephemeral streams, provided they have an ordinary high water mark (OHWM) -

reversing the prior position of some Corps districts that declined to assert jurisdiction 

over ephemeral streams. However, this new Corps policy was at the root of the Supreme 

Court case, Rapanos v. United States, 547 U.S. 715 (2006). In that case, the Agencies had 

attempted to assert jurisdiction over a ditch that drained a wetland but was very distant 

from any traditional navigable water. The case did not result in one clear test for 

jurisdiction, but four justices (the plurality) were joined by one justice (Justice Kennedy) 

in finding that the Agencies had overreached and they remanded the case back to the 

lower courts. In Rapanos, the Corps took the position that anything that had a bed, a bank 

and an ordinary high watermark was within their jurisdiction. Both the plurality and the 

Kennedy opinions disapproved this interpretation of the law and required more than that 

to establish federal jurisdiction. Under both opinions, there must be a surface water 

connection to a traditional navigable water. However, a surface hydrologic connection 

alone is not sufficient to establish jurisdiction. "[R]elatively continuous flow is a 

necessary condition for qualification as a 'water,' not an adequate condition." 547 U.S. at 

736 n.7 (emphasis in original) (plurality opinion). "[M]ere hydrologic connection should 

not suffice in all cases; the connection may be too insubstantial for the hydrologic linkage 

to establish the required nexus with navigable waters as traditionally understood." Id. at 

784-85 (Justice Kennedy concurring). In fact, Justice Kennedy criticized the plurality 

opinion for allowing jurisdiction to be based on a hydrologic connection involving 

relatively continuous flow without requiring a significant nexus. Id at 776-77 ("by saying 
Clean Water Rule Response to Comments – Topic 8: Tributaries

595

the Act covers wetlands (however remote) possessing a surface-water connection with a 

continuously flowing stream (however small), the plurality's reading would permit 

applications of the statute as far from traditional federal authority as are the waters it 

deems beyond the statute's reach"). The Proposed Rule would reinstate the Corps' prior 

attempts to assert jurisdiction over every so-called tributary based on the presence of a 

bed, a bank, and an OHWM based on ecological, not hydrological, connections. This 

goes beyond the Agencies' pre-2000 assertions of jurisdiction and beyond the limits set 

forth by the Supreme Court. And, as discussed below, it has created great uncertainty 

regarding the proposed scope of federal jurisdiction. (p. 5-6)

Agency Response: See summary response 8.1.1 and 8.1.2 for historic regulation of 

ephemeral streams by the agencies and the TSD and summaries in compendium 10 

for legal analysis of the Rapanos opinion. 

8.514 The Proposed Rule exempts gullies, rills, and non-wetland swales but does not define 

these terms in the rule language. The preamble defines gullies as: "relatively deep 

channels that are ordinarily formed on valley sides and floors where no channel 

previously existed." 79 Fed. Reg. at 22,218. The preamble defines rills as follows: "Rills 

are formed by overland water flows eroding the soil surface during rain storms." Id. 

According to the preamble, "Swales are distinct from streams in that they are nonchannelized, shallow trough-like depressions that carry water mainly during rainstorms or 

snowmelt." Id. at 22,219. According to the EPA, gullies, rills, and swales "typically lack 

an OHWM." Id. Thus, the distinction between an ephemeral stream that is categorically 

jurisdictional under the Proposed Rule and an exempt gully, rill or swale is whether or 

not a Corps or EPA officials thinks they can discern physical evidence of fluctuations in 

the lateral extent of the channel based on a natural line impressed on the banks, shelving, 

changes in the character of soil, destruction of terrestrial vegetation, the presence of litter 

and debris, or other appropriate means that consider the characteristics of the surrounding 

areas. 33 CFR 328.3(e). This is a highly subjective determination and is improper. As a 

result of this subjectivity, any two persons may disagree regarding whether a feature that 

is wet when it rains is an exempt gully, rill or swale or a tributary that is per se part of the 

"waters of the United States." (p. 6-7)

Agency Response: The final rule continues the longstanding practice of using the 

OHWM to determine the lateral extent of jurisdiction for tributaries. Where the 

physical characteristics of bed and banks and another indicator of ordinary high 

water mark no longer exist or are actively manipulated, the presence of bed and 

banks and OHWM may be determined by using other appropriate means that 

consider the characteristics of the surrounding areas. The OHWM continues to be 

identified using indicators of regular high flows whose return interval varies across 

the country based on climate, hydrology, and other factors. Any feature that does 

not meet these requirements, such as gullies, rills and swales, will not qualify as a 

tributary. These explicit requirements in the final rule provide regulatory certainty 

while continuing to rely on field indicators with a long history of use in the 

regulatory program. The agencies plan to continue to build on the more than a 

decade of effort spent improving the consistency and rigor of OHWM 

identifications, especially in the western US where two guidebooks for OHWM 

identification have already been developed, see 
Clean Water Rule Response to Comments – Topic 8: Tributaries

596

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates. 

8.515 This explanation does not provide any clarity so literally all water located in a flood plain 

or a riparian area could be regulated. This would include standing water and runoff from 

rain and snowmelt unless clearly excluded as a rill or gully or swale. And, if water is 

defined to include "aquatic systems" "as a whole," as described in the preamble, then 

jurisdiction could extend to the land as well as water based on the presence of plants, 

animals and insects. In addition, even if a water is outside the flood plain or riparian area, 

the definition of neighboring includes water connected to a jurisdictional by a shallow 

subsurface or confined surface connection. Neither of these terms is defined. However, 

the preamble to the proposed rule uses gullies, rills, and swales as examples of confined 

surface connections. So, theoretically, even if an erosional feature on the land is not itself 

a water of the United States, it can form a connection between water. For example, a low 

area of land that collects standing water could be jurisdictional even if it does not exhibit 

wetland features, and even if it is not in a flood plain or riparian area, if it is connected to 

a tributary by a swale, rill, or gully. (p. 8)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. The final rule clearly 

requires the presence of both bed and banks and another indicator of OHWM, if 

one is not present then the water does not qualify as a tributary. Wetlands, lakes, 

ponds, and other features lacking a bed and banks and/or OHWM are no longer 

defined as tributaries in the Final Rule, but may be considered jurisdictional 

“waters of the United States” as adjacent waters or similarly situated waters with a 

significant nexus to (a)(1) through (3) waters. Dry lands have not historically nor 

are now waters of the U.S. See TSD section 8 for further discussion of neighboring 

and the types of connections needed to determine adjacency. 

8.516 All Ttributaries of waters identified in paragraphs (s)( I) through (4) of this section; (p. 

14)

Agency Response: The final rule retains the “all” in (a)(5). 

8.517 (5) Tributary. The term means a surface water channel below the headwaters that is

physically characterized by the presence of a bed and banks and ordinary high water 

mark, as defined at 33 CFR 328.3(e), which contributes flow, either directly or through 

another surface water, to a water identified in paragraphs (s)(1) through (4) of this 

section, In addition, wetlands, lakes, and ponds are tributaries (even if they lack a bed and 

banks or ordinary high water mark) if they contribute flow, either directly or through 

another water to a water identified in paragraphs (s)(1) through (3) of this section. A 

surface water that otherwise qualifies as a tributary under this definition does not lose its 

status as a tributary if, for any lengths, there are one or more man-made breaks (such as 

bridges, culverts, pipes, or dams), or one or more natural breaks (such as wetlands at the 

head of or along the run of a stream, debris piles, boulder fields, or a stream that flows 

underground) so long as a bed and banks and an ordinary high water mark can be 

identifies upstream of the break. A tributary, including wetlands, can be a natural, manaltered or man-made water and includes waters such as rivers, streams, lakes, ponds, 
Clean Water Rule Response to Comments – Topic 8: Tributaries

597

impoundments, canals, and ditches not excluded in paragraph (t)(3) or (4) of this section. 

(p. 16)

Agency Response: See (b)(3) for the final definition and summary response 8.1 for 

a discussion of the definition. 

8.518 (12) Ordinary high water mark is the width of the channel that carries the mean annual 

flow. (p. 17)

Agency Response: No response required. 

K. Ransford (Doc. #15675)

8.519 6. This rule will take away ambiguity and make it easier to administer. States in the west 

are constantly denying that surface and groundwater flows are connected. These water 

sources almost always are. The proposed rule will clarify that this connection exists, and 

better enable the EPA to guard our nation's rivers. (p. 1)

Agency Response: The agencies agree, no response required. 

Anonymous (Doc. #16234)

8.520 The one place where they reveal their plan is when they claim that a wetland that does 

NOT flow into navigable waters has a NEGATIVE effect 011 navigable waters because 

of its LACK of effect. This is not only nonsense, it is directly contrary to the Supreme 

Court's Rapanos decision.

All of the language in the proposed regulations that reaches beyond navigable waters, 

their direct tributaries, and wetlands that directly flow into either, should be rejected 

because it rejects the statutory requirement that CWA enforcement must be tied to 

navigable waters. (p. 2)

Agency Response: See the TSD and summary responses in section 10. 

North Dakota Farmers Union (Doc. #16390)

8.521 "Wetland as a "Tributary"

We are particularly concerned about including "wetlands" in the definition of tributaries. 

Wetlands are not tributaries under any legal, plain language, or common sense 

understanding. If a discharge into a wetland is significantly affecting a navigable water, it 

will be jurisdictional as an "adjacent water" or significant nexus analysis of "other 

waters." Further, finding jurisdiction over the wetland as a tributary will only further 

confuse - not provide clarity to - farmer and rancher community.

Recommendation: We strongly request that "wetlands" are removed from any definition 

of tributary. (p. 4)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. The final rule clearly 

requires the presence of both bed and banks and another indicator of OHWM, if 

one is not present then the water does not qualify as a tributary. Wetlands, lakes, 

ponds, and other features lacking a bed and banks and/or OHWM are no longer 

defined as tributaries in the Final Rule, but may be considered jurisdictional 
Clean Water Rule Response to Comments – Topic 8: Tributaries

598

“waters of the United States” as adjacent waters or similarly situated waters with a 

significant nexus to (a)(1) through (3) waters. 

Virginia Poultry Federation (Doc. #16604)

8.522 In defining a tributary as a drainage feature having a bed, bank, and an ordinary high 

water mark (OHWM), the agencies want the public to believe that the assertion of CWA 

authority over "tributaries" is appropriate. This assertion fails to recognize the 

unnecessary inclusion of other land features that fall within the definition of "Tributary", 

such as these areas with drainage features that do not resemble any stream, brook or 

creek. Instead, the agencies advance new jurisdictional authority by introducing 

ambiguity and vague concepts of connectivity. The agencies justify this effort to broaden 

the boundaries of what the agencies consider a tributary because in "some regions of the 

country where there is a very low gradient, the banks of a tributary may be very low or 

may even disappear at times." 79 Fed. Reg. at 22202. This appears to be a thinly veiled 

justification to protect human health and the environment, without first demonstrating 

any harm that must be eliminated or prevented.

The uncertainty and potential liability associated with implementation of the rile is 

further aggravated by the EPA and the Corps determination that "[a] water that otherwise 

qualifies as a tributary under the proposed definition does not lose its status as a tributary 

if, for any length, there are one or more man-made breaks (such as bridges, culverts, 

pipes, or dams), or one or more natural breaks (such as debris piles, boulder fields, or a 

stream segment that flows underground) so long as a bed and banks and an ordinary high 

water mark can be identified upstream of the break." 79 Fed. Reg. at 22202. This 

determination prompts some practical, but critical questions for implementation of the 

rule. For example, how far will a farmer have to look "upstream" to ensure he is not 

liable for applying fertilizer or pesticide into an area that may lack a bed a bank and an 

OHWM yet is still considered a jurisdictional water? The agencies have specifically 

indicated that "[I]n many intermittent and ephemeral tributaries, including dry-land 

systems in the arid and semi-arid west, OHWM indicators can be discontinuous within an 

individual tributary due to the variability in hydrologic and climatic influences." Id. at 

22202. Consequently, how does a famer gauge his liability for CWA violations of 

$37,500 per day per occurrence and the risk of a citizen lawsuit when the discernible 

features required for a water to be a "tributary" do not exist in a specific location? It is 

difficult to understand how the agencies consider it logical that the proposed rule 

provides clarity and certainty to poultry and egg producers. (p. 30)

Agency Response: The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. The final rule clearly 

requires the presence of both bed and banks and another indicator of OHWM, if 

one is not present then the water does not qualify as a tributary. Wetlands, lakes, 

ponds, and other features lacking a bed and banks and/or OHWM are no longer 

defined as tributaries in the Final Rule, but may be considered jurisdictional 

“waters of the United States” as adjacent waters or similarly situated waters with a 

significant nexus to (a)(1) through (3) waters. See summary response 8.3 for a 

discussion of the relevance of breaks in OHWM and how far up valley to look to see 

if it was just a break in OHWM. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

599

D. Gillham (Doc. #16906)

8.523 3. The definition of tributary is too broad, so that one can conclude that essentially all 

drainage branches within each watershed will be regulated. (p. 2)

Agency Response: See summary responses 8.1 and 8.1.2. 

Shasta County Farm Bureau (Doc. #16924)

8.524 The Proposed Rule would modify existing regulations which have been in place for 

decades regarding which waters fall under federal jurisdiction under the Clean Water Act. 

In order to comply with these new regulations, farmers and ranchers will become more 

and more reliant on attorneys and consultants, making farming the land more difficult and 

costly. Points of concern include:

 Farmers and ranchers are stewards of the land and care about the environment and 

water quality. Farmers and ranchers know the ground they farm and should have 

clear guidance about how to comply with the law. Unfortunately, the Proposed 

Rule creates confusion and risk by providing the Agencies with almost unlimited 

authority to regulate, as they deem appropriate, any low spot where rainwater 

collects, including common farm ditches, ephemeral drainages, agricultural 

ponds, and isolated wetlands found in and near farms and ranches across the 

nation. (p. 1)

Agency Response: The final rule provides greater clarity to farmers and the 

general public by laying out explicit requirements for jurisdiction and greatly 

reducing the number of case by case determinations required. See summary 

responses 8.1 for discussion of tributaries, 6.2 for excluded ditches, and summaries 

in section 7 for non-jurisdictional features. 

Arizona Rock Products Association (Doc. #17055)

8.525 (...) The proposed rule attempts to shift the burden of demonstrating certain waters have 

a "significant nexus" to interstate or traditionally navigable waters from the EPA and 

Corps to the regulated stakeholders. The proposed rule attempts to accomplish this by, 

among other things, creating an expansive definition of the word "tributary," and 

including all tributaries as per se waters of the U.S. Consequently, an ephemeral wash 

which discharges a minimal amount of water into the Gila River two times a year would, 

by rule, be waters of the U.S. if the proposed rule passed. The need to show a "significant 

nexus" is subsumed by the proposed rule's expansive definition of tributary. An approach 

that is consistent with Supreme Court precedent would be to have a definition of 

tributary, to help reduce some regulatory uncertainty, but to couch the definition in terms 

of the "significant nexus" test. In other words, the EPA and Corps cannot, by rule, do 

away with the "significant nexus" test by creating an expansive definition of "tributary." 

(p. 2)

Agency Response: The final rule provides greater clarity to by laying out explicit 

requirements for jurisdiction and greatly reducing the number of case by case 

determinations required. See summary responses 8.1 for discussion of tributaries 

and the TSD and summary responses in section 10 for legal analysis of the final rule. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

600

8.526 The jurisdictional uncertainties in this rule are particularly problematic in the arid west. 

For example, the proposed rule fails to define the distinction between ephemeral 

"tributaries," which are potentially jurisdictional, and "gullies" or "rills," which are 

exempt. The proposed rule also irrationally exempts "vegetated swales," which differ 

from dry washes and other features of the arid west only in that they occur in more humid 

parts of the country and are therefore more likely to contain water. Similarly illogical is 

the proposed rule's definition of jurisdictional "tributaries" using the Corps definition of 

"ordinary high water mark." That concept created for waters that are "navigable-in-fact" 

is excessively broad as applied to the arid southwest where the land is crisscrossed with 

lines or cuts on the ground caused by water flow during infrequent but high intensity 

storms. The mere presence of physical signs that water flows across desert lands from 

time to time is insufficient to establish CWA jurisdiction, yet the proposed rule and 

associated draft connectivity report unjustifiably extend jurisdiction to areas that are

functionally land, not waters, contrary to the requirements of the CWA.

In the arid southwest, where the predominant tributaries are ephemeral streams, the 

subsurface connections are an extremely complex metrics of hydraulic flow, fracturing, 

and inundation and such tributaries may fluctuate, change and recourse with 

unpredictable and variable annual precipitation events. (p. 4)

Agency Response: See summary response to comment 8.1 for definition of 

tributaries, 8.1.2 for discussion of OHWM in the arid west, and 7.3.7 for discussion 

of gullies, rills and swales. 

8.527 The Definition of "Tributary" Under the Proposed Rule must be Revised.

For the first time EPA and the Corps have attempted to define the word "tributary." As 

proposed, a water feature is a "tributary" if it is natural or man-made and:

 it has a bed, bank, and ordinary high-water mark and flows to a traditionally 

navigable water, interstate water, a territorial sea, or any impoundment of the 

forgoing, or

 it is a wetland, lake, or pond that contributes flow to a traditionally navigable 

water, interstate water, or a territorial sea.

As written, a pond or flood control feature utilized in connection with an aggregate 

mining operation could be considered a tributary, and thus by rule "waters of the U.S." if 

it could contribute flow into a traditionally navigable or interstate water. Recall, a 

tributary can be perennial, seasonal, or ephemeral. Consequently, as written, this rule 

would allow the EPA to classify a lake or pond created by aggregate mining as a tributary 

if during ephemeral flow conditions, i.e. seasonal flooding, water could flow through the 

pond into the Gila River, or the Colorado River.

In addition, such an expansive definition places those in the construction materials 

industry in a precarious position with respect to citizen suits. If the EPA and the Corps 

insist on having such an expansive definition for the term tributary, then some provision 

must be added to protect against frivolous citizen suits. Consequently, we recommend an 

addition to the proposed rule which specifically provides sanctions against those filing 

citizen suits if it is determined that the original complaint was frivolous, meritless, or 

done for an improper purpose, such as harassment or delay. Having this provision would 
Clean Water Rule Response to Comments – Topic 8: Tributaries

601

help protect the regulated community from potential abuses of this expansive definition 

from citizens that are improperly abusing the protections the Clean Water Act is 

attempting the provide.

Finally, under the definition of tributary as written, a mining operation, which creates a 

manmade feature which potentially falls within the purview of the Clean Water Act, 

would not be able to alter or change the mining operation to reduce or eliminate impacts 

by the man-made feature to interstate or traditionally navigable waters. The definition of 

tributary should be revised to allow for man-made tributaries to be altered such that they 

are no longer "waters of the U.S." by rule. (p. 5 – 6)

Agency Response: The citizen suite provisions of the CWA are outside the scope 

of this rulemaking. The final rule contains a definition of tributary which was 

modified in response to comments to provide increased clarity. The final rule clearly 

requires the presence of both bed and banks and another indicator of OHWM, if 

one is not present then the water does not qualify as a tributary. Wetlands, lakes, 

ponds, and other features lacking a bed and banks and/or OHWM are no longer 

defined as tributaries in the Final Rule, but may be considered jurisdictional 

“waters of the United States” as adjacent waters or similarly situated waters with a 

significant nexus to (a)(1) through (3) waters. See summary responses under section 

7.4 and 7.5 for water features, including certain mining and construction features, 

excluded from the definition of waters of the U.S.

Atlantic Legal Foundation (Doc. #17361)

8.528 1. Diminished Clarity and Increased Scope 

We dispute the agencies' claim that the proposed rule will "narrow" the scope of 

regulatory jurisdiction.621 The most problematic of the proposed rule's flaws is the 

significant expansion of areas defined as "waters of the United States" by effectively 

removing the word "navigable" from the definition of those waters subject to the CWA.

The proposed rule's definition is based on a legally and scientifically dubious 

interpretation of the "significant nexus" concept advanced by Justice Kennedy in 

Rapanos. Contrary to the agencies' claims, the rule would place features such as ditches, 

ephemeral drainages, natural or man-made ponds, seeps, flood plains, and other 

occasionally or seasonally wet areas under federal jurisdiction.622 While this proposal is, 

in a sense, "narrower," because it facially decreases the water bodies subject to casespecific jurisdiction, it extends the agencies' per se jurisdiction well beyond current 

regulations by definitional changes and imprecise wording. (p. 3)

Agency Response: Dry lands have not historically nor are now waters of the U.S. 

The final rule provides greater clarity to by laying out explicit requirements for 

jurisdiction and greatly reducing the number of case by case determinations 

 

621 See Definition of "Waters of the United States" Under the Clean Water Act, 79 Fed. Reg. 22188, 22 189 

(proposed Apr. 21, 2014) [hereinafter Definition] (to be codified at 33 C.F.R. pt. 328).

622 EPA’s attempt to limit federal jurisdiction by excluding gullies, rills, and swales from the definition of "waters of 

the United States" is salutary, but more clarity is needed on what these exclusions actually encompass.
Clean Water Rule Response to Comments – Topic 8: Tributaries

602

required. See summary responses 8.1 for discussion of tributaries and the TSD and 

summary responses in section 10 for legal analysis of the final rule. 

D. Furtado (Doc. #17659)

8.529 LWVK supports the proposed rule for the protection it affords to wetlands, headwaters, 

intermittent and ephemeral streams. Tributary streams and our remaining functional 

wetlands must be protected under the Clean Water Act if municipal and domestic water 

supplies are to remain clean, affordable and sufficient to protect public health. This is 

about ensuring safe drinking water for all our citizens. They may only flow during parts 

of the year but they support water quality in downstream waters by filtering pollutants 

and capturing nutrients. (p. 1)

Agency Response: The agencies have maintained protection for all tributaries in 

the final rule. See TSD section 8 for discussion of adjacent waters. 

A. Cilimburg (Doc. #17667)

8.530 In addition, I also support including streams that have a bed, bank, and Ordinary High 

Water Mark in the definition of "waters of the United States." (p. 1) 

Agency Response: The final rule requires the presence of both bed and banks and 

another indicator of OHWM. 

D. Parsons (Doc. #17789)

8.531 I feel that it is critical that man made canals be included in the definition of waterways. 

Functionally they have the same deleterious side effect of any waterway, transporting 

harmful chemicals to sensitive natural habitats. This could not be more true than in 

southwest Florida. (p. 1)

Agency Response: The final rule requires the presence of both bed and banks and 

another indicator of OHWM which applies equally to man-made canals and natural 

or man-altered streams. See summary response 8.1. 

J. Holder (Doc. #17999)

8.532 Due to the lack of clarity of what is ephemeral I believe only intermittent or perennial 

streams that carry flow for multiple months at a time should be jurisdictional.

The lack of clear definition of ephemeral allows any project manager to justify any ditch 

as jurisdictional by saying there is one ohwm indicator such as sediment sorting.

Sediment sorting will happen in any situation when water carries sediment. When I walk 

through my neighborhood I notice the asphalt has been sorted in the grass on the side of 

the street.

Another example is that anywhere there is slope a channel will form over a long period of 

time from erosion. There is no current way to say that is an erosion feature as opposed to 

an ephemeral channel.

Either clarify it or throw it all out. No one can be secure with ephemeral being 

jurisdictional. (p. 1)
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603

Agency Response: See summary responses 8.1. 

R. McKinnon (Doc. #18845)

8.533 In addition, I support including streams that have a bed, bank, and ordinary high water 

mark in the definition of “waters of the US.” All of these provisions will help protect 

important wetlands and other waters in the state of Montana. (p. 1)

Agency Response: The final rule requires the presence of both bed and banks and 

another indicator of OHWM. 

Donald Shawcroft (Doc. #18569)

8.534 “Tributaries” Cannot Include Ephemeral Drainages

The definition of a “tributary” is one of the most expansive and problematic terms in the 

proposed rule. The American Heritage Dictionary (1982) defines “tributary” as “a stream 

or river flowing into a larger stream or river.” This common understanding of “tributary” 

simply does not include “ephemeral” drainages that only channel stormwater after heavy 

rains. Most of the time, ephemeral drainages are dry land—they are not flowing rivers or 

streams. This description fits perfectly many of the “rivers” and “streams” we have in 

Colorado. Yet, the Agencies insist that “[t]ributaries that are small, flow infrequently, or 

are of substantial distance from the nearest (a)(1) through (a)(4) water, e.g., headwater 

perennial, intermittent, and ephemeral tributaries” are nevertheless part of the tributary 

network regulated by this proposal. 79 Fed. Reg. at 22,206.

The Agencies have proposed an overly broad “tributary” definition focusing on the 

presence of a bed, bank, ordinary high water mark (OHWM) and any minimal amount of 

flow that eventually reaches (directly or through any number of other paths and channels) 

to a creek or stream that in turn ultimately flows to a traditional navigable water. See 79 

Fed. Reg. at 22,263. The terms “bed” and “bank” simply mean land with lower elevation 

in between lands of higher elevation. This includes land with only subtle changes in 

elevation—any land where rainwater naturally channels as it flows downhill. All but the 

flattest terrain will have natural paths of lower elevations that water will follow. Under 

the Proposed Rule, Nearly Every Ditch Could Be Regulated as a Tributary None of the 

current regulations defining “waters of the U.S.” names ditches. In fact, the CWA does 

not define ditches as “waters of the U.S.,” but as “point sources” that may discharge to 

“waters of the U.S.” See 33 U.S.C. § 1362(14).

Nevertheless, over the years, the Agencies have. The rule would provide: “The term 

tributary means a water physically characterized by the presence of a bed and banks and 

ordinary high water mark, as defined at 33 CFR 328.3(e), which contributes flow, either 

directly or through another water, to a water identified in paragraphs (a)(1) through (4) of 

this section.” (p. 3)

Agency Response: See summary responses 8.1 for discussion of the tributaries 

definition and regulation of ephemeral streams and 6.2 for discussion of excluded 

ditches. 
Clean Water Rule Response to Comments – Topic 8: Tributaries

604

Anonymous (Doc. #18801)

8.535 (...) 5) The definitions proposed in the rule actually create more confusion. A good 

example is the definition of "Tributary" which creates a difficult situation for local 

government entities in making determinations in reviewing and approving construction 

permits including grading and fill permits. The same problem also exists for small 

businesses. Local governments and small businesses often do not have the resources to 

insure compliance with the existing rule and the proposed rule creates more confusion.

(...) (p. 1 – 2)

Agency Response: The final rule provides greater clarity to by laying out explicit 

requirements for jurisdiction and greatly reducing the number of case by case

determinations required. See summary responses 8.1 for discussion of tributaries. 

See also responses in 7 addressing relevance of definition to stormwater 

management features and certain construction and mining activities.

City of Olathe Kansas (Doc. #18982)

8.536 Defining jurisdictional streams by the presence of bed, banks, and high water mark is 

current Corp practice; however, the determination of such features can be subjective. The 

City of Olathe suggests a quantifiable method for determining jurisdiction based on 

stream order, stream flow, and/or watershed size. Regardless of the method, jurisdictional 

waters should be mapped with related GIs data available to local governments for use in 

land use planning and regulation of development. (p. 1)

Agency Response: The final rule clarifies the extent of tributaries by adding 

additional context and field indicators to the definition and specifically identifying 

the features that excluded from the definition of waters of the U.S in (b)(1) – (7). 

See summary response 8.1 for further discussion of the definition of tributaries and 

8.1.1 for the relevance of flow regime. Regional variation in hydrology and climate 

among other factors do not allow for the development of nationally consistent and 

scientifically supported cutoffs for tributaries based on stream order, stream flow or 

watershed size, see further discussion in the TSD. Determinations of jurisdiction 

are done on a case by case basis based on the best information available and they 

are only valid for five years because environmental conditions which can shape the 

outcome can change over time. For example changes in ground and surface water 

levels due to changes in water usage and losses through evapotranspiration. While 

maps of all the jurisdictional or non-jurisdictional waters are not feasible, the 

agencies have provided clarity in terms of the identifying features and analysis 

required to determine the jurisdictional status of a given waterbody. 

Jon Klingel (Doc. #19166)

8.537 Intermittent Streams and Ephemeral Waters (including arroyos and playas)

These waters are important to people, livestock and wildlife because they provide:

 Drinking water for people, livestock and wildlife

 Increased primary productivity (forage),

 Increased plant diversity,
Clean Water Rule Response to Comments – Topic 8: Tributaries

605

 Increased plant density,

 Recharge of ground water, and

 Periodic surface water.

Low lying areas such as arroyos, playas and ephemeral streams tend to have richer soils 

due to the nutrients and fine grain sediments that accumulate in and on the flood plain 

during runoff events. Soil moisture also is greater than surrounding uplands and the 

sediments are storage for runoff water. The higher nutrient and moisture level supports 

greater plant growth both in terms of biomass and species diversity. The difference in 

plant growth between these low lying areas and the surrounding upland is well 

documented and should be obvious even to the most casual observer. The sand and gravel 

sediments in these areas absorb considerable water. Light and even moderate 

precipitation events that cause runoff from the uplands are generally absorbed by these 

sediments and often don't cause a surface water flow in the drainage. Larger runoff events 

saturate the sediments and cause flows which can move considerable sediment, including 

soluble and insoluble material and contaminants (natural or man-made). Some of the 

water in the sediments generally penetrates to and recharges deeper aquifers. Intermittent 

streams, especially in desert mountain country, often have segments and pools of 

perennial water where underlying bedrock forces the water to the surface. The flow 

through these segments and pools clearly shows that water is flowing through the 

sediments but not exposed to the surface except intermittently. These small segments of 

perennial water are often the only water available to wildlife over large desert areas and 

have a strong influence on the distribution, abundance and diversity of wildlife.

The result of ephemeral waters and intermittent streams for wildlife is increased thermal 

and hiding cover, increased nesting and denning habitat, increased food availability, and 

a water supply to springs and intermittent pools. During periods of flow, ephemeral 

streams provide connection between normally isolated habitat segments and populations. 

This temporary connectivity appears to be important to amphibians (and likely some 

reptiles and mammals) in maintaining genetic flow and recolonization of isolated 

habitats. The increased wildlife activity associated with ephemeral streams is well 

documented and is apparent even to the casual observer, by the increased bird activity 

and tracks. Even in the Santa Fe area it is obvious that the arroyos are the primary travel 

and resting areas for deer, coyotes and sometimes bobcats and black bears. In some areas 

(e.g. southeast of Santa Fe where I live) water within the sediments of arroyos is the 

domestic well water supply used by people in their homes, including drinking water.

Arroyos, ephemeral and intermittent streams are connected portions of downstream 

perennial waters (where perennial waters occur downstream), but function in a pulsating 

manner in response to precipitation events. Sediment and chemicals dumped in an 

arroyo eventually end up in the perennial stream and water soluble compounds also 

end up in the ground water and drinking water. However, rates of travel of sediments 

and chemicals vary depending on size, density and solubility. Los Alamos National 

Laboratory (LANL) is a good example. Contaminants dumped in arroyos 60 years ago 

are becoming an issue today. Water soluble perchlorate (primarily a byproduct of high 

explosives & rocket fuel) has shown up in a spring along the Rio Grande below LANL 

and one water well in Los Alamos is shut down due to perchlorate. While species that use 
Clean Water Rule Response to Comments – Topic 8: Tributaries

606

ephemeral waters and the associated habitat are adapted to intermittency and can cope 

with many environmental changes, this does not necessarily translate into an advantage 

during pollution exposure. (p. 1 – 2)

Agency Response: See summary response 8.1. 

8.538 Intermittent streams, and Ephemeral streams and playas:

Intermittent streams, with perennial segments and pools of surface water are sometimes 

the only surface water available to wildlife in desert mountains and therefore critical to 

the distribution, abundance and diversity of wildlife. For example, Guadalupe Canyon 

with its intermittent stream in extreme southwest New Mexico has the highest 

concentration of State Threatened and Endangered wildlife in the State.

Some species are adapted to arid conditions and the periodic (sometimes sporadic) 

presence of available water. Millions of shorebirds and waterfowl migrate through the 

Playa Lakes Region in the spring and fall utilizing the ephemeral playas. Other species 

burrow into the soil or use burrows of other animals to reach moisture, emerging when 

ephemeral surface water is present. Other types of adaptations include: aestivation, dried 

eggs of some species remain viable for years, some mollusks have impermeable shells 

that prevent desiccation when closed, rapid breeding and development of young, highly 

concentrated urine, glands that extrude salt, bodies tolerant to dehydration, and some 

species meet all their water needs with metabolic water.

Ephemeral waters are essential for all three species of spadefoot toads in New Mexico. 

Spadefoots stay burrowed in the soil (several years has been documented) until 

conditions are suitable for breeding. Emergence from burrows is apparently triggered by 

thunder storms and breeding occurs quickly (as short as one night) in ephemeral waters. 

Eggs hatch in as little as 15 hours, and tadpoles metamorphose and leave the ephemeral 

waters in as little as 13 days. Possible threats to these species include pesticide 

contamination of the ephemeral waters.

Ephemeral waters also appear to be important to Box Turtles, Garter Snakes, and tiger 

salamanders. Many of the crustaceans and insects, mentioned later under playa lakes, also 

occur in ephemeral and intermittent streams. Even some fish use ephemeral waters. For 

example, Pecos Pupfish and White Sands Pupfish (both State Threatened, State "Species 

of Greatest Conservation Need", and federal Species of Concern) are exploiters which 

will move into ephemeral waters when available. Some sport fishing waters in NM are 

intermittent, including portions of: the Canadian River, Center Fire Creek, Conchas 

River, Conejos Creek, Cottonwood Creek, Felix River, Pecos River, Salt Creek, Walnut 

Creek, Yeso Creek, Mimbres River, Running Water Draw, Tularosa Creek, Three Rivers, 

and Tajique Creek. 

Very conservatively, at least one fifth of NM vertebrate species, excluding fish, (19%, 

127 species) use ephemeral and/or intermittent waters.

These 127 vertebrate species include:

9 taxa classified as State and/or federal threatened, endangered or candidate

8 taxa classified as State and/or federal sensitive or species of concern

24 taxa classified as State "Species of Greatest Conservation Need"
Clean Water Rule Response to Comments – Topic 8: Tributaries

607

25 game species

1 taxa endemic to NM

10 species listed as of cultural importance to Pueblo Tribes (p. 3 – 4)

Agency Response: See summary response 8.1. 

8.539 Domestic Water Supply

The alluvial sediments under ephemeral streams provide domestic water, including 

drinking water, for some homes, perhaps very many homes, in New Mexico. For 

example, I have lived southeast of Santa Fe for 19 years. The area is pinyon-juniper 

bisected by arroyos and the geology is granite bedrock. The only water is apparently 

within the sediments in the arroyos, and at least some (possibly most) of the wells in our 

area are within or adjacent to an arroyo. My family has been drinking arroyo sediment 

well water for 19 years. The three families downstream use a shallow well in the arroyo 

and an adjacent arroyos has at least one well in the arroyo bottom. If water soluble 

contaminants are dumped into the arroyo upstream from my house, they will be in our 

drinking water, and our neighbors. I believe an analysis of wells around New Mexico and 

the Southwestern U.S. would show many wells dependent upon water in the 

unconsolidated alluvial deposits of ephemeral streams, both for domestic use and 

livestock watering. People are probably not drinking untreated water from perennial 

streams but they are from the alluvial deposits under ephemeral streams. Perhaps 

some ephemeral waters should have more protective standards than perennial 

waters. (p. 4 – 5)

Agency Response: Drinking water standards for private wells and restrictions 

based on designated use as a drinking water supply are beyond the scope of this 

rulemaking. See summary discussion 8.1 for the definition of tributaries in the final 

rule. 

J. R. Dorney (Doc. #19235)

8.540 The rule proposes to use bed and bank and ordinary high water marks as criteria to 

identify jurisdictional tributaries. I support the use of these criteria on an interim basis but 

urge the Corps and EPA to develop robust, field-based methodologies (on a regional 

basis) similar to the widely used NC Stream Identification Method (NC Division of 

Water Quality. 2010. Methodology for Identification of Intermittent and Perennial 

Streams and Their Origins. Version 4.11. Raleigh, NC; available at http://porta 

l.ncdenr.org/web/wq/swp/ws/401/waterresources/streamdeterminations) which has now 

been verified as accurate by the peer-reviewed literature (K.M. Fritz, W.R.Wenerick and 

M.S. Kostich. 2013. A validation study of a rapid field-based rating system for 

discriminating among flow permanence classes of headwater streams in South Carolina. 

Environmental Management 52(5):1286-1298). This method was developed in NC and 

has been successfully taught to students in over 50 classes in NC, VA, SC, GA, TN and 

AL since 1999. I note that use of ordinary high water marks would exclude most 

ephemeral stream channels in NC since ephemeral channels in NC generally do not have 

this feature. This seems to be a reasonable approach since the Corps in NC has routinely 

exempted ephemeral channels from jurisdiction for the 404 Permit process. (p. 3)
Clean Water Rule Response to Comments – Topic 8: Tributaries

608

Agency Response: The final rule continues the longstanding practice of using the 

OHWM to determine the lateral extent of jurisdiction for tributaries. The final rule 

does not change the definition or alter the methods for identification of OHWM. 

The OHWM continues to be identified using indicators of regular high flows whose 

return interval varies across the country based on climate, hydrology, and other 

factors. The Corps and EPA plan to continue to build on the more than a decade of 

effort spent improving the consistency and rigor of OHWM identifications, see 

http://www.erdc.usace.army.mil/Media/FactSheets/FactSheetArticleView/tabid/9254

/Article/486085/ordinary-high-water-mark-ohwm-research-development-andtraining.aspx for updates.

Halliburton Energy Services, Inc. (Doc. #19458)

8.541 In addition, the proposed definition specifies that a water that otherwise qualifies as a 

tributary under the definition "does not lose its status as a tributary if, for any length, 

there are one or more man-made breaks (such as bridges, culverts, pipes, or dams), or 

one or more natural breaks (such as wetlands at the head of or along the run of a stream, 

debris, piles, boulder fields, or a stream that flows underground) so long as a bed and 

banks and an ordinary high water mark can be identified upstream of the break” 

Examples of tributaries with breaks include dry-land systems in the arid and semi-arid 

west that may have stretches which flow through low gradient areas and do not exhibit an 

ordinary high-water mark, or a tributary that loses its bed and banks over a stretch 

characterized by wetlands.

In effect, federal jurisdiction would extend to all tributaries, no matter how remote or 

ephemeral and without regard to the significance of a specific tributary's relationship to a 

traditional navigable water - i.e., without regard to the nature of the flow in the stream, 

the evaporative losses within the stream and distance to a navigable-in-fact water (which 

might preclude a contaminant from ever reaching that water), or the relative effect of the 

tributary on navigable waters compared to the impact of more directly adjacent but 

unregulated areas. Indeed, the proposed definition goes further, extending beyond what 

would commonly be viewed as a "tributary" by ignoring breaks in the OHWM to capture 

additional upstream stretches with even further attenuated connections to traditional 

navigable waters. Thus, no matter how implausible the likelihood of conveyance of 

pollutants to navigable waters, the "tributary" would be per se jurisdictional. (p. 4)

Agency Response: See summary response 8.3. and discussion of comments 

regarding “breaks” in OHWM.

8.542 The proposed definition of tributary is an expansion of jurisdiction from current practice 

that has meaningful consequences. For example, in the arid west, under current 

application of regulations most ephemeral drainages, ditches, and depressions do not 

require a jurisdictional determination at all - in practice, the Corps does not extend 

jurisdiction to these features. Perhaps the exclusions for gullies, swales and other 

erosional features will be appropriately expansive, but the rule and the preamble lack that 

clarity. For other features, photographic documentation of breaks in the OHWM of 

drainages are regularly used to establish the limits of federal jurisdiction, limits that are 

currently recognized by the Corps. (p. 5)
Clean Water Rule Response to Comments – Topic 8: Tributaries

609

Agency Response: See summary response 8.1 and 8.1.2 for discussion of the 

historic extent of jurisdiction and practice identifying tributaries. See summary 

response 7.3.7 for discussion of gullies, rills and swales. 

REFERENCES

Comments included above in this document discuss the Proposed Rule, and some include 

citations to various attachments and references, which are listed below. The agencies do not 

respond to the attachments or references themselves, rather the agencies have responded to the 

substantive comments themselves above, as well as in other locations in the administrative 

record for this rule (e.g., the preamble to the final rule, the TSD, the Legal Compendium). In 

doing so, the agencies have responded to the commenters’ reference or citation to the report or 

document listed below as it was used to support the commenters’ comment. Relevant comment 

attachments include the following:

Battelle Energy Alliance, LLC. Map showing intermittent channels of the Big Lost River, Little 

Lost River, and Birch Creek on the INL Site. (Doc. #16448, p. 9)

Conservation Law Foundation et al. v. USEPA et al. Case No. 1:10-cv-11455-MLW, 

Memorandum in Support of Defendants’ Motion for Summary Judgment (Doc. #15822.5)

Defenders of Wildlife and Patagonia Area Resource Alliance. Compilation of Preliminary 

Comments from Individual Panel Members on the Scientific and Technical Basis of the 

Proposed Rule Titled “Definition of ‘Waters of the United States’ Under the Clean Water 

Act” (As of August 14, 2014) (Doc. #16394.2)

Drake, Darrel, Brenda Tozer, and Geoffrey Stillwell. 2012. Prairie Pothole Wetlands and Region 

(PPR). Semester Project for ES-767, Wetland Environments, Earth Science Department, 

Emporia State University (2012) (Doc. #16394.3)

Earthworks and The Patagonia Area Resource Alliance. October 2014. The Hermosa Mine 

Proposal: Potential Impacts to Patagonia’s Water Supply. (Doc. #16394.6)

Hansen, William. 2001. Identifying Stream Types and Management Implications. (Doc. #5570.2)

Hansen, William. 2007. Sediment from a Small Ephemeral Gully in South Carolina. (Doc. 

#5570.3)

High Lakes Aquatic Alliance Foundation. Case Study: Intermittent and Ephemeral Streams and 

Lakes in Arid and Semi-Arid Landscapes in the Western United States. (Doc. # 15212.1)

James, L. Using LiDAR data to map gullies and headwater streams under forest canopy: South 

Carolina, USA. (Doc. #5570.4)

Landmark Legal Foundation. Exhibit 1: Steams and Waterbodies in Missouri (Doc. #15364, p. 

14)
Clean Water Rule Response to Comments – Topic 8: Tributaries

610

Landmark Legal Foundation. Exhibit 2: EPA Region 7 National Wetlands Inventory (Doc. 

#15364, p. 15)

Landmark Legal Foundation. Exhibit B: Gully with bed, bank, and ordinary high water mark 

(Doc. #16534, p. 18)

Los Angeles Waterkeepers. Attachment A. Compton Creek and Dominguez Channel and prime 

examples of such waterbodies (Doc. #15060)

Mersel, Matthew K., Lindsey E. Lefebvre, and Robert W. Lichvar. August 2014. “A Review of 

Land and Stream Classifications in Support of Developing a National Ordinary High Water 

Mark (OHWM) Classification,” U.S. Army Engineer Research and Development Center 

(ERDC) (Doc. # 14428.3)

Mersel, Matthew K. and Robert W. Lichvar. August 2014. “Occurrence and Distribution of 

Ordinary High Water Mark (OHWM) Indicators in Non-Perennial Streams in the Western 

Mountains, Valley, and Coast Region of the United States,” U.S. Army Engineer Research 

and Development Center (ERDC) (Doc. # 14428.4)

Missouri Corn Growers Association. Appendix A: Photographic Log (Doc. #16569, p. 90)

National Corn Growers Association. Appendix 1: Results from Agricultures’ WOTUS Mapping 

Initiative (AWMI) (Doc. #14968, p. 24)

National Parks Conservation Association. Figure 2: “Headwater Stream Length, as a Proportion 

of Total Stream Length Within Each 8 Digit HUC Watershed, in the U.S., Excluding Alaska, 

as Computed Querying the NHD RAD v2.0 for Reaches That Have No Other Inflowing 

Streams at the 1:100,000 Scale. The NHD RAD v2.0 Does not Capture Streams Under 1 mile 

(i.e., 1.61 km) in Length.” Image and description source: Nadeau and Rains 2007. (Doc. 

#15130, p. 7)

National Parks Conservation Association. Figure 3: “Combined Intermittent and Ephemeral 

Stream Length in the U.S., Excluding Alaska, as a Proportion of Total Stream Length Within 

Each 8 Digit HUC Watershed, as Computed by Querying the NHD RAD v2.0 for Reaches 

That Contain Water Only Part of the Year at the 1:100,000 Scale. The NHD RAD v2.0 does 

not capture streams under 1 mile (i.e., 1.61 km) in length.” Image and description source: 

Nadeau and Rains 2007. (Doc. #15130, p. 8)

Pierce, Robert J. April 2003. Technical Principles Related to Establishing the Limits of 

Jurisdiction for Section 404 of the Clean Water Act. (Doc. #15822.14)

Sealaska. Maps: Election Creek Valley, Black Bear Valley and Saltery Creek (Doc. #16671, p. 

24-26)
Clean Water Rule Response to Comments – Topic 8: Tributaries

611

Sierra Club, Cumberland Chapter. Map titled Percentage of Surface Drinking Water from 

Intermittent, Ephemeral, and Headwater Streams in Kentucky (Doc. #15466, p. 8)

Southwest Kansas Groundwater Management District No. 3 Local Groundwater Management 

Policy 2014-1 (Doc. #16465.1)

U.S. Army Corps of Engineeers Baltimore District. Oct. 17, 1994. Branch Guidance Letter, 

CENAB-OP-R, No.95-01. (Doc. #15822.3)

U.S. Department of the Interior and U.S. Geological Survey. Trends in Streamflow of the San 

Pedro River, Southeastern Arizona, and Regional Trends in Precipitation and Streamflow in 

Southeastern Arizona and Southwestern New Mexico: Professional Paper 1712. (Doc. 

#16394.5)

U.S. Environmental Protection Agency. 2009. Figure 1: Percentage of Surface Drinking Water 

from Intermittent, Ephemeral, and Headwater Streams. (Doc. #15130, p. 7)

U.S. Environmental Agency Science Advisory Board (SAB) Draft Report (09/17/14) to Assist 

Meeting Deliberations (Doc. #16394.1)

U.S. General Accounting Office. February 2004. Waters and Wetlands: Corps of Engineers 

Needs to Evaluate Its District Office Practices in Determining Jurisdiction. A Report to the 

Chairman, Subcommittee on Energy, Policy, Natural Resources and Regulatory Affairs, 

Committee on Government Reform, House of Representatives (GAO-04-297). (Doc. 

#15822.2)

U. S. House of Representatives. March 30, 2004. Inconsistent Regulation of Wetlands and Other 

Waters. Document Number 108-58. (Doc. #15822.8)

Utah, State of, Office of the Governor. Exhibit B: Gully with bed, bank, and ordinary high water 

mark. (Doc. #16534, p. 18)

Utah, State of, Office of the Governor. Exhibit D: Map of Potential Jurisdictional Waters in 

Utah. (Doc. #16534, p. 18)

Western Urban Water Coalition. Appendix A: Photo Log (Doc. #15178.1, p. 36)

Winter, Thomas C., Judson W. Harvey, O. Lehn Franke, and William M. Alley.1998. Ground 

Water and Surface Water A Single Resource: U.S. Geological Survey Circular 1139. (Doc. 

#16394.4)

Woolford, Sam, Shannon Bonney, and Ross Pringle. October 2014. Physical, Chemical, and 

Biological Impacts of Geographically Isolated Wetlands on Waters of the United States. 

(Doc. #15446, p. 9; Doc. # 15020.1)
Clean Water Rule Response to Comments – Topic 8: Tributaries

612

Woolford, Sam, and Matt Carroll. July 2014. Evidence of Significant Impacts of Coastal Plain 

Depressional Wetlands on Navigable Waters. (Doc. #15020.2)

Zamzow, K. Comments on Connectivity of Streams and Wetlands to Downstream Waters. 

Washington DC. (Doc. #18006.2)

In addition, commenters submitted the following relevant references. These are copied into this 

document as they were submitted by commenters. The agencies have not verified the references, 

or the validity of hyperlinks.

33 C.F.R. 328.4(c)(a). (Doc. #19540, p. 60)

33 C.F.R. § 1362.14; 33 C.F.R. § 1342. (Doc. #19540, p. 71)

40 Fed. Reg. 31,320, 31,321 (July 25, 1975). (Doc. #15882.1, p. 12; Doc. #19540, p. 71)

42 Fed. Reg. 37,112 (1977). (Doc. #19540, p. 71)

51 Fed. Reg. at 41217 (Doc. #15882.1, p. 13; Doc. #19540, p. 72)

65 Fed. Reg. 12818, 12823, 12824 (Mar. 9, 2000). (Doc. #15882.1, p. 12; Doc. #18016, p. 4; 

Doc. #19540, p. 71)

77 Fed. Reg. 10288-10289 (February 21, 2012) (Doc. #15178.1, p. 15)

79 Fed. Reg. at 22201

Aldridge, B.N. 1970. Floods of November 1965 to January 1966 in the Gila River Basin, 

Arizona and New Mexico, and adjacent basins in Arizona. US Geological Survey WaterSupply Paper 1850-C. (Doc. #19540, p. 68 & 69)

Alexander, R. G., R. A. Smith, G. E. Schwarz, E. W. Boyer, J. V. Nolan, and J. W. Brakebill. 

2008. Differences in phosphorus and nitrogen delivery to the Gulf of Mexico from the 

Mississippi River basin. Environmental Science & Technology 42:822-830. (Doc. #15123, p. 

4)

Alexander, R. G., R. A. Smith, and G. E. Schwarz. 2000. Effect of stream channel size on the 

delivery of nitrogen to the Gulf of Mexico. Nature 403:758-761. (Doc. #15123, p. 3)

Allan. J.D. and M.M. Castillo. 2007. Stream Ecology, 2nd ed. New York: Springer. Print. (Doc. 

#19540, p. 66)

Allen, Aaron and D. Malanchuk. June 2001. Guidelines for Jurisdictional Determinations for 

Waters of the United States in the Arid Southwest. USACOE, South Pacific Division. (Doc. 

#16394, p. 7)
Clean Water Rule Response to Comments – Topic 8: Tributaries

613

Allen, A. December 18, 2002. Remarks at 5th Annual California Regulatory Coordination 

Conference, USCOE South Pacific Division, Sacramento, California. (Doc. #16394, p. 7)

Allen, David and Amanda Rodewald, EPA. Oct. 17, 2014. Letter to Gina McCarthy, EPA 

regarding SAB Review of the Draft EPA Report, Connectivity of Streams and Wetlands to 

Downstream Waters: A Review and Synthesis of the Scientific Evidence) available at 

http://yosemite.epa.gov/sab/sabproduct.nsf/WebBoard/AF1A28537854F8AB85257D740050

03D2/$File/EPA-SAB-15-001+unsigned.pdf. (Doc. #16460, p. 10)

Arizona Department of Environmental Quality. Permit No. AZG2013-001. Part 3.1.1.1.1. Runon Management (Doc. #14407, p. 11)

Association of State Wetland Managers. April 2014. Report on State Definitions, Jurisdiction 

and Mitigation Requirements in State Programs for Ephemeral, Intermittent and Perennial 

Streams in the United States. http://aswm.org/stream_mitigation/streams_in_the_us.pdf. 

(Doc. #14131, p. 4)

Bayless, M. A., M. G. McManus, and J. F. Fairchild. 2003. Geomorphic, water quality and fish 

community patterns associated with the distribution of Notropis topeka in a Central Missouri 

watershed. American Midland Naturalist 150:58-72. (Doc. #15123, p. 3)

Bell, Larry, Director of the New Mexico Department of Game and Fish. April 15, 2003. Letter to 

EPA (NMDGF comment letter on the 2003 ANPRM). Doc. #14974, p. 3)

Benjamin v. Douglas Ridge Rifle Club, 673 F.Supp.2d (D. Or. 2009) (Doc. #16413, p. 27)

Benke, A.C., and C.E. 2005. Rivers of North America. Cushing. Editors. Burlington, MA: 

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Blazer, Vicki, Scott Phillips, and Edward Pendleton. Fish Health, Fungal Infections, and 

Pfiesteria: The Role of the U.S. Geological Survey, U.S. Geological Survey Fact Sheet 114-

98. (Doc. #14620, p. 5)

Boulder Area Sustainability Information Network. 2005. Two Mile Creek Information, available 

at http://bcn.boulder.co.us/basin/watershed/2mile.html. (Doc. #16460, p. 16)

Bower, Michael R. et al. September 2008. Habitat Features Affect Bluehead Sucker, 

Flannelmouth Sucker, and Roundtail Chub Across a Headwater Tributary System in the 

Colo. River Basin. 23 J. Freshwater Eco. available at 

http://www.uwyo.edu/frahel/pdfs/bower-2008-1.pdf. (Doc. #16460, p. 13)

Brownback, Sam, Governor of Kansas. July 14, 2011. Letter to Nancy Stoner, Acting Assistant 

Administrator for Water, U.S. Environmental Protection Agency. (Doc. #13956, p.10)

Bukaveckas, P. A. 2009. Rivers. Pages 721-732 in G. E. Likens, editor. Encyclopedia of Inland 

Waters. Elsevier, Oxford, UK. (Doc. #15123, p. 3)
Clean Water Rule Response to Comments – Topic 8: Tributaries

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