Letter From Dr. David T. Allen, Chair, Science Advisory Board (SAB), to Gina McCarthy, Administrator, U.S. Environmental Protection Agency, on SAB Consideration of the Adequacy of the Scientific and Technical Basis of EPA's Proposed Rule Titled 'Definition of Waters of the United States Under the Clean Water Act' (Sept. 30, 2014)

• Author: Margaret 'Peggy' Strand/Lowell Rothschild
• Pages: 695-703

Letter From Dr. David T. Allen, Chair, SAB, to Gina McCarthy, Administrator, EPA Page 695

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON D.C. 20460

OFFICE OF THE ADMINISTRATOR

SCIENCE ADVISORY BOARD

September 30, 2014

EPA-SAB-14-007

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 Proposed Rule titled “Definition of Waters of the United

States under the Clean Water Act”

Dear Administrator McCarthy:

As part of its statutory duties, the Science Advisory Board (SAB) may provide 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 provides advice and

comments related to that proposal. Briefly, the SAB finds that the available science provides 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 science supports the conclusion that the types of water

bodies identified as waters of the United States in the proposed rule exert strong influence 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 July 26, 2013, Science Advisory Board (SAB)

Discussions about EPA Planned Actions in the Fall 2012 Unified (Regulatory) Agenda and their

Supporting Science (EPA-SAB-14-003), 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,