UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON D.C. 20460

OFFICE OF THE DMINISTRATOR
SCIENCE ADVISORY BOARD September 30, 2014

EPA

- SAB

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The Honorable Gina McCarthy

Administrator U.S. Environmental Protection Agency 1200 Pennsylvania Avenue, N.W. Washington, D.C. 20460

Subject: Science Advisory Board (SAB) Consideration of the Adequacy of the Scientific and

Technical Basis of the EPA’s P ro posed R ule titled “ Definition of Waters of the United

S tates u nder the Clean Water Act ”

Dear Administrator McCarthy :

As part of its statutory duties, the Science Advisory Board (SAB) may provid e advice and comment to

you on the adequacy of the scientific and technical basis of certain planned EPA actions. The

Environmental Research, Development, and Demonstration Authorization Act of 1978 (ERDDAA) requires the agency to make available to the SAB proposed criteria documents

, standards, limitations,

or regulations provided to any other Federal agency for formal review and comment, together with

relevant scientific and technical information on which the proposed action is based. The SAB may then provide advice and comments on the adequacy of the scientific and technical basis of the proposed

action.

This letter documents the SAB’s activities related to the proposed rule “Definition of ‘Waters of the United States’ Under the Clean Water Act” released on March 25, 2014, and prov ides advice and comments related to that proposal. Briefly, the SAB finds that the available science provide s an adequate scientific basis for the key components of the proposed rule. Although water bodies differ in degree of connectivity that affects the extent of influence they exert on downstream waters (i.e., they

exist on a “connectivity gradient”) , the available scie nce supports the conclusion that the types of water

bodies identified as waters of the United States in the proposed rule exert strong in fluence on the physical, chemical, and biological integrity of downstream waters

. Additional comments regarding the Board’s major findings and recommendations to strengthen the science supporting the rule are provided

below.

Background

In SAB deliberations leading to the letter sent to you on Ju ly 26, 2013, Science Advisory Board (SAB) Discussions about EPA Planned Actions in the Fall 2012 Unified (Regulatory) Agenda and their Supporting Science (EPA

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- 003), the chartered SAB discussed the agency’s plan to propose the

rule . The Board also discussed the EPA’s plan to use the EPA’s September 2013 draft report,Connectivity of Streams and Wetlands to Downstream Waters: A Review and Synthesis of the Scientific

Evidence (connectivity synthesis document ) to inform determinations in the rule. In those discussions, the chartered SAB highlighted the importance of th e rulemaking and the need for SAB advice and comment on the adequacy of the science to support the rule.

An ad hoc panel of the SAB has completed a peer review of the EPA’s draft connectivity synthesis

report

. The SAB’s peer review report was approved on September 26, 2014

, and is being finalized to send to you shortly . For that peer review , t he agency did not ask the SAB to consider the adequacy of

the scien ce to support the proposed rule . Because this question was not considered during the peer

review , I requested the panel members to comment on the scientific and technical basis of the EP A proposed rule

. In response to my request, t he SAB panel held public teleconferences on August 20 and 21, 2014, (79 FR 40100

- 40101) to discuss this topic.

A Work Group of chartered SAB members considered comments provided by panel members, agency

repres entatives

, and the public on the adequacy of the science informing the proposed rule. This Work Group, chaired by Board member Dr. James Mihelcic, then took the lead in SAB deliberations on this topic at a public teleconference held on September 29, 2014

, where the chartered Board discussed the

advice and comments in this letter

.

SAB Advice and comment on the science informing the proposed rule

T he SAB finds that the available science provide s an adequate scientific basis for key components of the

propose d rule. The following comments summarize major points regarding the adequacy of the scientific and technical basis of the proposed action. The SAB also provides recommendations for strengthening the science informing the rule.

Tributaries

There is stro ng scientific evidence to support the EPA’s proposal to include all tributaries within the jurisdiction of the Clean Water Act. T ributaries, as a group, exert strong influence on the physical, chemical, and biological integrity of downstream waters

, even t hough 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 n ot all tributaries have ordinary high water marks

. A n 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 w ater 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., la kes, ponds, wetlands). T hus, the EP A may want to consider

whether flow

- through lentic systems should be included as adjacent waters and wetlands , rather than as

tributaries.

Adjacent Waters and Wetlands

The available science supports the EPA’s proposal to include adjacent waters and wetla nds as waters of

the United States

. This is because adjacent waters and wetlands have a strong influence on the physical, chemical, and biological integrity of navigable waters. Importantly, the available science supports

2defining adjacency or determinatio n of adjacency on the basis of functional relationships, not on how close an adjacent water is to a navigable water. T he Board also notes that local shallow subsurface water
sources and regional groundwater sources can strongly affect connectivity. Thus, t he Board advises the

EPA that adjacent waters and wetlands should not be defined solely on the basis of geographical proximity or distance to jurisdictional waters

. The science also supports consideration of the temporal dimension of connectivity to define adjacent waters and wetlands. This is particularly important in arid systems with intermittent and ephemeral waters.

Other Waters

The scientific literature has established that “other waters” can influence downstream waters, particularly when considered in aggregate. Thus, it is appropriate to define “other waters” as w aters of

the United States on a case

- by

- case basis, either alone or in combination with similarly situated waters in the same region. As mentioned previously for adjacent waters, distance should not be the sole indicator used to evaluate the connection of “other waters” to jurisdictional waters.

There is also adequate scientific evidence to support a determination that certain subcategories and types

of “other water s ” in particular region s of the United States (e.g., Carolina and Delmarva Bays, Texas coastal prairie wetlands, prairie potholes, pocosins, western vernal pools) are similarly situated (i.e., they have a similar influence on the physical, chemical and biological integrity of downstream waters and are similarly situated on the landscape) and thus could be considered waters of the United States

. Furthermore, as the science continues to develop, other sets of wetlands may be identified as “similarly

situated.” The Bo ard notes , however, that t he existing science does not support excluding groups of “other waters” or subcategories thereof.

Exclusions

The Clean Water Act exclusions of groundwater and certain other exclusions listed in the proposed rule

and the current regulation do not have scientific justification . For example, the Clean Water Act excludes groundwater, including groundwater drained through subsurface drainage systems . T he

available science , however, shows that groundwater connections, particularly via shallow flow paths in unconfined aquifers, can be critical in supporting the hydrology and biogeochemical functions of

wetlands and other waters. Groundwater also can connect waters and wetlands that have no visible

surface connections.

The proposed rule identifies other exclus ions not justified by science. T here is , for example, a lack of scientific knowledge to determine whether ditch es should be categorically excluded. M any ditches in the

Midwest would be excluded under the proposed rule because they were excavated wholly in uplands

, drain only uplands

, and have less than perennial flow . However, these ditches may drain areas that

would be identified as wetlands under the Cowardin classification system and may provide certain ecosystem services

. A lthou gh gullies, rills, and non

- wetland swales are excluded by the rule , the proposed rule’s preamble notes that these features can be important conduits for moving water between jurisdictional waters, making them important with respect to hydrological and othe r forms of connectivity. Also, although excluded from jurisdiction under the proposed rule, artificial lakes or ponds, or reflection pools, created by excavation, diking, or construction can be directly connected to jurisdictional waters by groundwater , wh ich may be shallow as well as deep groundwater in unconfined aquifers

. It is also not clear in the proposed rule how engineered structures would be treated, especially given changes in technology, urbanization, or economic sectors . Some examples of such ch anges in

3engineered structures include : (1) design of stormwater management systems that more closely mimic natural systems (i.e., low impact development technology) ; (2) demand for lower quality water sources

that result s in construction of desalination b rine storage basins ; (3) the impact of urbanization that has led to construction of artificial lakes and ponds that may have connections to downstream waters ; (4) agricultural sectors that utilize aquaculture and rice paddies ; and (5) expanding domestic en ergy production that results in construction of structures such as oil and gas tank basins and in

- stream sediment ponds used to collect waste from surface coal mining

.

Finally, the SAB has a specific recommendation for strengthening the presentation of th e science informing this regulatory action. The SAB recommends that the EPA clarify in its general communications and in the preamble to the final rule that “significant nexus” is a legal term, not a
scientific term

.

Recommendations for next steps

In conclusion the SAB has determined that the available science , as summarized in the preamble to the proposed rule and the EPA technical document peer reviewed by the SAB, provides an adequate scientific and technical basis for the proposed rule . T he Board h as made several recommendations to strengthen definitions and reconsider exclusions in the proposal

. For a more detailed summary of many of the points in this letter, please see the memorandum provided by the Chair of the SAB Panel for the

Review of the EP A Water Body Connectivity Report

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The SAB does not expect to provide further advice and comment on the scientific and technical basis for

the proposed action at this time. We look forward to your response to our comments on the science supporting this im portant rulemaking.

On behalf of the SAB, I thank you for the opportunity to support the EPA through consideration of the science supporting this proposed action

.

Sincerely,

/Signed/

Dr. David T. Allen, Chair Science Advisory Board

Enclosure 1) Roster, EPA Science Advisory Board

1 September 2, 2014, Memorandum from the Dr. Amanda Rodewald to Dr . David Allen, 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.” Available at http://yosemite.epa.gov/sab/sabproduct.nsf/F6E197AC88A38CCD85257D49004D9EDC/$File/Rodewald_Memorandum_W OUS+Rule_9_2_14.pdf (last accessed 09/29/14). 1

4NOTICE

This report has been written as part of the activities of the EPA Science Advisory Board (SAB), a public advisory group providing extramural scientific information and advice to the Administrator and other officials of the Environmental Protection Agency. The SAB is structured to provide balanced, expert assessment of scientific matters related to problems facing the agency. This report has not been reviewed for approval by the agency and, hence, the contents of this report do not represent the views and po licies of the Environmental Protection Agency, nor of other agencies in the Executive Branch of the Federal government, nor does mention of trade names of commercial products constitute a recommendation for use. Reports of the SAB are posted on the EPA web site at http://www.epa.gov/sab

.

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### U.S. Environmental Protection Agency Science Advisory Board

CHAIR

Dr. David T. Allen , Gertz Regents Professor of Chemical Engineering and the Director of the Center for Energy and Environmental Resources, The University of Texas, Austin, TX

MEMBERS Dr. George Alexeeff , Director, Office of Environmental Health Hazard Assessment, California Environmental Protection Agency, Oakland, CA

Dr. Pedro Alvarez , Department Chair and George R. Brown Professor of Engineering, Department of Civil & Environmental Engineering, Rice University, Houston, TX

Dr. Joseph Arvai , Svare Chair in Applied Decision Research, Department of Geography, University of Calgary, Calgary, Alberta, Canada

Dr. Thomas Burbacher , Professor, Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA

Dr. Ingrid Burke , Director and Wyoming Excellence Chair, Haub School and Ruckelshaus Institute of Environment and Natural Resources, Univers ity of Wyoming, Laramie, WY

Dr. Edward T. Carney , Departmental Senior Science Leader and Director of Predictive Toxicology Center, Toxicology & Environmental Research and Consulting, The Dow Chemical Company, Midland, MI

Dr. Peter Chapman , Principal and Senior Environmental Scientist, Golder Associates Ltd, Vancouver, BC, Canada

Dr. Terry Daniel , Professor Emeritus of Psychology and Natural Resources, Department of Psychology, School of Natural Resources, University of Arizona, Tucson, AZ

Dr. George Daston , Victor Mills Society Research Fellow, Global Product Stewardship, The Procter & Gamble Company, Mason, OH

Dr. Costel Denson , Managing Member, Costech Technologies, LLC, Newark, DE

Dr. Otto C. Doering III , Professor, Department of Agricultural Eco nomics, Purdue University, W. Lafayette, IN

Dr. Michael Dourson , President, Toxicology Excellence for Risk Assessment, Cincinnati, OH

iiDr. Joel Ducoste , Professor, Department of Civil, Construction, and Environmental Engineering, College of Engineering, N orth Carolina State University, Raleigh, NC

Dr. David A. Dzombak , Walter J. Blenko, Sr. University Professor and Head of Civil and Environmental Engineering , College of Engineering, Carnegie Mellon University, Pittsburgh, PA

Dr. T. Taylor Eighmy , Vice Chancellor for Research and Engagement, Office of Research, University of Tennessee, Knoxville, TN

Dr. Elaine M. Faustman , Professor and Director, Environmental and Occupational Health Sciences, University of Washington, Seattle, WA

Dr. R. William Field , Professor, Department of Occupational and Environmental Health, and Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA

Dr. H. Christopher Frey , Distinguished University Professor, Department of Civil, Construction

an d Environmental Engineering, College of Engineering, North Carolina State University, Raleigh,

NC

Dr. John P. Giesy , Professor and Canada Research Chair, Veterinary Biomedical Sciences and Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatch ewan, Canada

Dr. Steven Hamburg , Chief Scientist, Environmental Defense Fund, Boston, MA

Dr. Cynthia M. Harris , Director and Professor, Institute of Public Health, Florida A&M University, Tallahassee, FL

Dr. Robert J. Johnston , Director of the George Perkins Marsh Institute and Professor, Economics, Clark University, Worcester, MA

Dr. Kimberly L. Jones , Professor and Chair, Department of Civil Engineering, Howard University, Washington, DC

Dr. Catherine Karr , Associate Professor

- Pediatrics and Envi ronmental and Occupational Health

Sciences and Director

- NW Pediatric Environmental Health Specialty Unit, University of Washington, Seattle, WA

Dr. Madhu Khanna , Professor, Department of Agricultural and Consumer Economics, University of

Illinois at Urb ana

- Champaign, Urbana, IL

Dr. Nancy K. Kim , Independent Consultant, Independent Consultant, Albany, NY

Dr. Francine Laden , Mark and Catherine Winkler Associate Professor of Environmental Epidemiology, Harvard School of Public Health, and Channing Divisio n of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA

Dr. Lois Lehman

- McKeeman , Distinguished Research Fellow, Discovery Toxicology, Bristol

Myers Squibb, Princeton, NJ

iiiDr. Cecil Lue

- Hing , President, Cecil Lue

- Hing & Assoc. Inc., Burr Ridge, IL

Dr. Elizabeth Matsui , Associate Professor, Pediatrics, School of Medicine, Johns Hopkins University, Baltimore, MD

Dr. Kristina D. Mena , Associate Professor, Epidemiology, Human Genetics, and Environmental Sciences, School of Public Health, University of Texas Health Science Center at Houston, El Paso,

TX

Dr. Surabi Menon , Director of Research, ClimateWorks Foundation, San Francisco, CA

Dr. James R. Mihelcic , Professor, Civil and Environmental Engineering, University of South Florida, Tampa, FL

Dr. Christine Moe , Eugene J. Gangarosa Professor, Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA

Dr. H. Keith Moo

- Young , Chancellor, Office of Chancellor, Washington State University , Tri

Cities, Richland, WA

Dr. Eileen Murphy , Director of Research Development, Office of Research and Economic Development, Rutgers University, Piscataway, NJ

Dr. James Opaluch , Professor and Chair, Department of Environmental and Natural Resource Economics, College of the Environment and Life Sciences, University of Rhode Island, Kingston, RI

Dr. Duncan Patten , Emeritus Professor, School of Life Sciences Arizona State University, Tempe,

AZ

Dr. Martin Philbert , Dean and Professor, Environmental He alth Sciences, School of Public Health, University of Michigan, Ann Arbor, MI

Mr. Richard L. Poirot , Air Quality Planning Chief, Air Quality and Climate Division, Vermont Department of Environmental Conservation, Montpelier, VT

Dr. Stephen Polasky , Fesle r

- Lampert Professor of Ecological/Environmental Economics, Department of Applied Economics, University of Minnesota, St. Paul, MN

Dr. Amanda Rodewald , Director of Conservation Science, Cornell Lab of Ornithology and Associate Professor, Department of Natu ral Resources, Department of Natural Resources, Cornell University, Ithaca, NY

Dr. James Sanders , Executive Director, Skidaway Institute of Oceanography, University of Georgia, Savannah, GA

Dr. William Schlesinger , President, Emeritus, Cary Institute of Ecosystem Studies, Millbrook, NY

ivDr. Gina Solomon , Deputy Secretary for Science and Health, Office of the Secretary, California Environmental Protection Agency, Sacramento, CA

Dr. Daniel O. Stram , Professor, Department of Preventive Medicine, Division of Biostatistics, University of Southern California, Los Angeles, CA

Dr. Peter S. Thorne , Professor and Head, Department of Occupational & Environmental Health Director, Environmental Health Sciences Research Center, University of Iowa, Iowa City, IA

Dr. P aige Tolbert , Professor and Chair, Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA

Dr. Jeanne VanBriesen , Professor, Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, PA

Dr. John Vena , Professor and Founding Chair, Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC

Dr. Peter J. Wilcoxen , Associate Professor, Economics and Public Administration, The Maxwell School, Sy racuse University, Syracuse, NY

SCIENCE ADVISORY BOARD STAFF Dr. Angela Nugent , Designated Federal Officer, U.S. Environmental Protection Agency, Science Advisory Board, Washington, DC

v