NATIONAL ACADEMY PRESS
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NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competencies and with regard for appropriate balance.
This report has been reviewed by a group other than the authors according to procedures approved by a Report Review Committee consisting of members of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine.
Support for this project was provided by the U.S. Environmental Protection Agency under Agreement No. CX-821125-01-0 and the U.S. Department of Agriculture Natural Resources Conservation Service under Agreement No. SCD-68-3475-3-161.
The Director, Grants Administration Division, has approved a deviation from 40 CFR 30.518 of EPA's Assistance Regulations. This approval permits a waiver of EPA's peer review process and submission of the draft final report. The recipient agrees that the following disclaimer will be added to all documents published under this project.
"Although the results described in this document have been funded wholly or in part by the United States Environmental Protection Agency under Assistance Agreement X821125010 to the National Academy of Sciences, it has not been subjected to the Agency's peer and administrative review and therefore may not necessarily reflect the views of the Agency and no official endorsement should be inferred."
Cover art by Raphael Lopez, San Diego, California
Library of Congress Cataloging-in-Publication Data
Wetlands: characteristics and boundaries.
p. cm
William M. Lewis, Jr., chair.
Includes bibliographical references and index.
ISBN 0-309-05134-7 (cloth)
1. Wetlands. 2. Wetland ecology. 3. Wetland conservation— Government policy—United States. I. Lewis, William M., 1945-. II. National Research Council (U.S.). Committee on Characterization of Wetlands.
QH87.3W475 1995
333.91'8'0973—dc 20 95-440
Copyright 1995 by the National Academy of Sciences. All rights reserved.
Printed in the United States of America
COMMITTEE ON CHARACTERIZATION OF WETLANDS
WILLIAM M. LEWIS, JR., Chair,
University of Colorado, Boulder, Colorado
BARBARA BEDFORD,
Cornell University, Ithaca, New York
FRED BOSSELMAN, IIT
Chicago Kent College of Law, Chicago, Illinois
MARK BRINSON,
East Carolina University, Greenville, North Carolina
PAUL GARRETT,
Federal Highway Administration, Washington, District of Columbia
CONSTANCE HUNT,
The World Wildlife Fund, Washington, District of Columbia
CAROL JOHNSTON,
University of Minnesota, Duluth, Minnesota
DOUGLAS KANE,
University of Alaska, Fairbanks, Alaska
A. MICHAEL MACRANDER,
Shell Oil Company, Houston, Texas
JAMES MCCULLEY,
Environmental Consultants, Inc., Christiana, Delaware
WILLIAM J. MITSCH,
The Ohio State University, Columbus, Ohio
WILLIAM PATRICK, JR.,
Louisiana State University, Baton Rouge, Louisiana
ROGER POST,
Alaska Department of Fish and Game, Fairbanks, Alaska
DON SIEGEL,
Syracuse University, Syracuse, New York
R. WAYNE SKAGGS,
North Carolina State University, Raleigh, North Carolina
MARGARET STRAND,
Bayh, Connaughton & Malone, P.C., Washington, District of Columbia
JOY B. ZEDLER,
San Diego State University, San Diego, California
BEST Liaison
EDWIN H. CLARK, II,
Clean Sites, Inc., Alexandria, Virginia
WSTB Liaison
DAVID L. FREYBERG,
Stanford University, Stanford, California
Federal Liaisons
GREGORY E. PECK,
Environmental Protection Agency
MICHAEL A. FRITZ,
Environmental Protection Agency
MICHAEL L. DAVIS,
Department of the Army Corps of Engineers
KAREN KOCHENBACH,
Department of the Army Corps of Engineers
BILLY TEELS,
Department of Agriculture, Natural Resources Conservation Service
MARGE KOLAR,
Department of the Interior, Fish and Wildlife Service
MIKE LONG,
Department of the Interior, Fish and Wildlife Service
JOHN R. HALL,
Department of Commerce, National Marine Fisheries Service
WATER SCIENCE AND TECHNOLOGY BOARD
DAVID L. FREYBERG, Chair,
Stanford University, Stanford, California
BRUCE E. RITTMANN, Vice Chair,
Northwestern University, Evanston, Illinois
LINDA M. ABRIOLA,
University of Michigan, Ann Arbor, Michigan
J. DAN ALLEN,
Chevron USA, Inc., New Orleans, Louisiana
PATRICK BREZONIK,
Water Resources Research Center, St. Paul, Minnesota
WILLIAM M. EICHBAUM,
The World Wildlife Fund, Washington, District of Columbia
WILFORD R. GARDNER,
University of California, Berkeley, California
WILLIAM GRAF,
Arizona State University, Tempe, Arizona
THOMAS M. HELLMAN,
Bristol-Myers Squibb Company, New York, New York
CHARLES C. JOHNSON, Jr.,
U.S. Public Health Service, Washington, District of Columbia (Retired)
CAROL A. JOHNSTON,
University of Minnesota, Duluth, Minnesota
WILLIAM M. LEWIS, JR.,
University of Colorado, Boulder, Colorado
CAROLYN H. OLSEN,
Brown and Caldwell, Pleasant Hill, California
CHARLES R. O'MELIA,
The John Hopkins University, Baltimore, Maryland
IGNACIO RODRIGUEZ-ITURBE,
Texas A&M University, College Station, Texas
HENRY J. VAUX, JR.,
University of California, Riverside, California
Staff
STEPHEN D. PARKER, Director
JEANNE AQUILINO, Administrative Specialist
ANGELA BRUBAKER, Senior Project Assistant
SHEILA D. DAVID, Senior Staff Officer
CHRIS ELFRING, Senior Staff Officer
ETAN GUMERMAN, Research Associate
ANITA A. HALL, Administrative Assistant
GARY KRAUSS, Staff Officer
JACQUELINE MACDONALD, Senior Staff Officer
MARY BETH MORRIS, Senior Project Assistant
GREGORY NYCE, Senior Project Assistant
BOARD ON ENVIRONMENTAL STUDIES AND TOXICOLOGY
PAUL G. PASSER, Chair,
Miami University, Oxford, Ohio
MICHAEL J. BEAN,
Environmental Defense Fund, Washington, District of Columbia
EULA BINGHAM,
University of Cincinnati, Cincinnati, Ohio
EDWIN H. CLARK II,
Clean Sites, Inc., Alexandria, Virginia
ALLAN H. CONNEY,
Rutgers University, Piscataway, New Jersey
ELLIS COWLING,
North Carolina State University, Raleigh, North Carolina
JOHN L. EMMERSON,
Portland, Oregon
ROBERT C. FORNEY,
Unionville, Pennsylvania
ROBERT A. FROSCH,
Harvard University, Cambridge, Massachusetts
KAI LEE,
Williams College, Williamstown, Massachusetts
JANE LUBCHENCO,
Oregon State University, Corvallis, Oregon
GORDON ORIANS,
University of Washington, Seattle, Washington
FRANK L. PARKER,
Vanderbilt University, Nashville, Tennessee
GEOFFREY PLACE,
Hilton Head, South Carolina
DAVID P. RALL,
Washington, District of Columbia
LESLIE A. REAL,
Indiana University, Bloomington, Indiana
KRISTIN SHRADER-FRECHETTE,
University of South Florida, Tampa, Florida
BURTON H. SINGER,
Princeton University, Princeton, New Jersey
MARGARET STRAND,
Bayh, Connaughton & Malone, P.C., Washington, District of Columbia
GERALD VAN BELLE,
University of Washington, Seattle, Washington
BAILUS WALKER, JR.,
Howard University, Washington, District of Columbia
Staff
JAMES J. REISA, Director
DAVID J. POLICANSKY, Associate Director and Program Director for Natural Resources and Applied Ecology
KULBIR BAKSHI, Program Director for Committee on Toxicology
CAROL MACZKA, Program Director for Human Toxicology and Risk Assessment
LEE R. PAULSON, Program Director for Information Systems and Statistics
RAYMOND A. WASSEL, Program Director for Environmental Sciences and Engineering
COMMISSION ON GEOSCIENCES, ENVIRONMENT, AND RESOURCES
M. GORDON WOLMAN, Chairman,
The Johns Hopkins University, Baltimore, Maryland
PATRICK R. ATKINS,
Aluminum Company of America, Pittsburgh, Pennsylvania
EDITH BROWN WEISS,
Georgetown University Law Center, Washington, District of Columbia
JAMES P. BRUCE,
Canadian Climate Program Board, Ottawa, Ontario, Canada
WILLIAM L. FISHER,
University of Texas, Austin, Texas
EDWARD A. FRIEMAN,
Scripps Institution of Oceanography, La Jolla, California
GEORGE M. HORNBERGER,
University of Virginia, Charlottesville, Virginia
W. BARCLAY KAMB,
California Institute of Technology, Pasadena, California
PERRY L. MCCARTY,
Stanford University, California
S. GEORGE PHILANDER,
Princeton University, Princeton, New Jersey
RAYMOND A. PRICE,
Queen's University at Kingston, Ontario, Canada
THOMAS A. SCHELLING,
University of Maryland, College Park, Maryland
ELLEN SILBERGELD,
Environmental Defense Fund, Washington, District of Columbia
STEVEN M. STANLEY,
The Johns Hopkins University, Baltimore, Maryland
VICTORIA J. TSCHINKEL,
Landers and Parsons, Tallahassee, Florida
Staff
STEPHEN RATTIEN, Executive Director
STEPHEN D. PARKER, Associate Executive Director
MORGAN GOPNIK, Assistant Executive Director
JAMES MALLORY, Administrative Officer
SANDI FITZPATRICK, Administrative Associate
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Acknowledgments
Many individuals assisted the committee in its task by participating in committee meetings, helping to plan field trips, and providing background information. The committee is especially thankful for the generous assistance provided by Mike Fritz, EPA; Mike Long, FWS; Billy Teels, NRCS; and Russell Theriot and Karen Kochenbach of USACE. The committee received valuable advice and assistance from Greg Peck, EPA; Marge Kohlar, FWS; and Mike Davis, USACE.
Field trips held in conjunction with committee meetings helped the committee better understand the problems of wetlands delineation. We would like to express our appreciation to the following people who assisted the committee and NRC staff during these field trips.
Kent Island, Maryland
Leander Brown, USACE
Woody Francis, USACE
Alex Dolgos, USACE
Tom Filip, USACE
Charlie Rhodes, Jr., EPA
Norman Melvin, NRCS
Vicksburg, Mississippi
James Gosselink, Louisiana State University
Randy Pearson, Space Remote Sensing Center, Stennis Space Center, MS
Larry Harper, USACE
David Lofton, USACE
Harvey Huffstatler, USACE
Tom Welborn, EPA
David Jones, NRCS
Raymond Callahan, NRCS
David Pettry, Mississippi State University
Sedona, Arizona
Kevin Martin, Soil and Environmental Consultants, Inc., Raleigh, NC
Robert Pierce, Wetlands Science Applications, Inc., Poolesville, MD
Duncan Patten, University of Arizona
Tom Yocum, EPA
Wendy Melgin, EPA
Kathy Kunz, USACE
Fred Weinman, EPA
Mary Butterwick, EPA
David Cooper, Colorado State University
Marie Sullivan, FWS
Ft. Myers, Florida
Maurice Mausbach, NRCS
Kevin Reush, consultant, Lakeland, FL
Kevin Erwin, consultant, Ft. Myers, FL
Robin Lewis, Lewis Environmental Services, Tampa, FL
Public Session in Ft Myers:
Jim Shepard, National Council of the Paper Industry for Air and Stream Improvement
Susan Asmus, National Association of Home Builders
Jamestown, North Dakota
Ned Euliss, FWS
Porter Reed, FWS
Arnold van der Valk, Iowa State University
Dan Smith, USACE
Lewis Cowardin, FWS
Jimmie Richardson, North Dakota State University
Harold Kantrud, FWS
Public session in Jamestown:
Don Parrish, American Farm Bureau
Don Etler, Iowa Drainage District Association
Vic Legler, Landowners Association of North Dakota
Gerald Eid, North Dakota Home Builders Association
Kenneth Dierks, Lanley and McDonald Consultants, Virginia Beach, VA
Greg Larson, Minnesota Board of Water and Soil Resources
Jay Leitch, North Dakota State University
Others
Gary Jellick, Greenhorne & O'Mara, Inc.
Ralph Tiner, FWS
Kim Santos, FWS
Dennis Tressel, NRCS
Preface
Principles for federal regulation of wetlands have been fundamentally challenged several times over the past 20 years. One legacy of these challenges has been a reduction in the credibility of all regulatory practice related to wetlands. For this reason, the U.S. Congress requested that the Environmental Protection Agency ask the National Research Council (NRC) to create a committee that would study the scientific basis for characterization of wetlands. This committee was formed in 1993 through the NRC's Water Science and Technology Board and its Board on Environmental Studies and Toxicology. The committee was asked to review and evaluate the consequences of alternative methods for wetland delineation and to summarize the scientific understanding of wetland functions. Specifically mentioned in the committee's charge are the issues of wetland definition, the structure and functioning of wetlands, and regional differences among wetlands. Members of the committee were drawn from a broad range of expertise, regional perspectives, and professional experience.
After its first meeting in Washington, D.C., the committee met in eastern Maryland, the lower Mississippi River valley, Arizona, southwest Florida, and the prairie pothole region of North Dakota. At each of these locations, the committee spent some of its time on field investigations organized under the direction of federal agency personnel and private consultants familiar with regional problems of delineation. This field experience assisted the committee members in their discussion of regional issues. The meetings also included two special sessions for public commentary (in Florida and in North Dakota) and presentations by nongovernment specialists in delineation.
The NRC committee has reached broad consensus on the issues related to its
charge. In this report, the committee presents a reference definition of wetlands that sets the stage for a fresh look at existing regulatory definitions and for reconsideration of the confusion surrounding parameters, criteria, and indicators. In addition, the committee offers an overview of wetland functions as they relate to the protection of wetlands. Finally, the committee provides many recommendations and conclusions related to criteria and indicators. Although these recommendations and conclusions do not in themselves constitute a new delineation manual, they specify the essential framework and principles around which a new universal federal manual can be prepared by federal agency personnel. Many of the conclusions and recommendations underscore the committee's confidence in the fundamental soundness of current regulatory practice for characterizing and delineating wetlands. Changes that have been suggested by the committee typically involve refinements of practice rather than drastic change.
The committee's report will be scrutinized carefully for bias favoring or opposing the protection of wetlands. The committee members hold a range of personal viewpoints on the degree of rigor with which wetlands should be protected and on the uniformity with which protection should extend across wetlands, but the committee leaves these matters for resolution through law and administrative policy. The committee's task has been to analyze present regulatory practice in relation to wetland delineation and to recommend changes that might bolster the objectivity and scientific validity of wetland delineation and identification. In general, the committee has been impressed with the professionalism and scientific credibility that make up the foundation of federal expertise in characterization and delineation of wetlands. This foundation, when combined with a federal commitment to the use of scientific principles applied with regional realism, should steadily improve public confidence in the national system for characterization of wetlands.
The Committee on wetlands Characterization has placed extraordinary demands on members of the NRC staff. The rapid pace of work, extensive logistical arrangements, and coordination of two NRC boards required experience and great dedication from the staff. The committee is indebted particularly to Sheila David, David Policansky, Tania Williams, and Greg Nyce of the National Research Council, and to David Greene of the University of Colorado's Center for Limnology, for extensive staff work on this project. In addition, the committee greatly appreciates the many briefings and assistance with field trips provided by the staff of the U.S. Environmental Protection Agency, the U.S. Army Corps of Engineers, the U.S. Natural Resources Conservation Service, the U.S. Fish and Wildlife Service, and others.
William M. Lewis, Jr., Chairman