Mississippi River Water Quality and the Clean Water Act: Progress, Challenges, and Opportunities (2008)

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MISSISSIPPI RIVER WATER QUALITY AND THE CLEAN WATER ACT Progress, Challenges, and Opportunities Committee on the Mississippi River and the Clean Water Act Water Science and Technology Board Division on Earth and Life Studies 

THE NATIONAL ACADEMIES PRESS 500 Fifth Street, N.W. Washington, DC 20001 NOTICE: The project that is the subject of this report was approved by the Govern- ing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineer- ing, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropri- ate balance. Support for this project was provided by the McKnight Foundation under Grant No. 05-083. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the organization that provided support for the project. International Standard Book Number-13: 978-0-309-11409-7 International Standard Book Number-10: 0-309-11409-8 Additional copies of this report are available from the National Academies Press, 500 Fifth Street, N.W., Lockbox 285, Washington, DC 20055; (800) 624-6242 or (202) 334-3313 (in the Washington metropolitan area); Internet, http://www.nap. edu. Copyright 2008 by the National Academy of Sciences. All rights reserved. Printed in the United States of America. 

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COMMITTEE ON THE MISSISSIPPI RIVER AND THE CLEAN WATER ACT DAVID A. DZOMBAK, Chair, Carnegie Mellon University, Pittsburgh, Pennsylvania H. H. CHENG, University of Minnesota (emeritus), St. Paul ROBIN K. CRAIG, Florida State University, Tallahassee OTTO C. DOERING III, Purdue University, West Lafayette, Indiana WILLIAM V. LUNEBURG, JR., University of Pittsburgh, Pittsburgh, Pennsylvania G. TRACY MEHAN III, The Cadmus Group, Inc., Arlington, Virginia JAMES B. PARK, Consultant, Loami, Illinois NANCY N. RABALAIS, Louisiana Universities Marine Consortium, Chauvin JERALD L. SCHNOOR, University of Iowa, Iowa City DAVID M. SOBALLE, U.S. Army Corps of Engineers Research and Development Center, Vicksburg, Mississippi EDWARD L. THACKSTON, Vanderbilt University (emeritus), Nashville, Tennessee STANLEY W. TRIMBLE, University of California, Los Angeles ALAN H. VICORY, Ohio River Valley Water Sanitation Commission, Cincinnati National Research Council Staff JEFFREY W. JACOBS, Study Director ANITA A. HALL, Senior Program Associate  

WATER SCIENCE AND TECHNOLOGY BOARD CLAIRE WELTY, Chair, University of Maryland, Baltimore County JOAN G. EHRENFELD, Rutgers University, New Brunswick, New Jersey SIMON GONZALEZ, National Autonomous University of Mexico, Mexico City CHARLES N. HAAS, Drexel University, Philadelphia, Pennsylvania JAMES M. HUGHES, Emory University, Atlanta, Georgia THEODORE L. HULLAR, Cornell University, Ithaca, New York KIMBERLY L. JONES, Howard University, Washington, D.C. G. TRACY MEHAN III, The Cadmus Group, Inc., Arlington, Virginia JAMES K. MITCHELL, Virginia Polytechnic Institute and State University, Blacksburg DAVID H. MOREAU, University of North Carolina, Chapel Hill LEONARD SHABMAN, Resources for the Future, Washington, D.C. DONALD I. SIEGEL, Syracuse University, Syracuse, New York SOROOSH SOROOSHIAN, University of California, Irvine HAME M. WATT, Consultant, Washington, D.C. JAMES L. WESCOAT, JR., University of Illinois at Urbana-Champaign GARRET P. WESTERHOFF, Malcolm Pirnie, Inc., Fair Lawn, New Jersey Staff STEPHEN D. PARKER, Director LAUREN E. ALEXANDER, Senior Staff Officer LAURA J. EHLERS, Senior Staff Officer JEFFREY W. JACOBS, Senior Staff Officer STEPHANIE E. JOHNSON, Senior Staff Officer WILLIAM S. LOGAN, Senior Staff Officer M. JEANNE AQUILINO, Financial and Administrative Associate ANITA A. HALL, Senior Program Associate ELLEN A. DE GUZMAN, Research Associate DOROTHY K. WEIR, Research Associate MICHAEL J. STOEVER, Project Assistant vi 

Preface T he Mississippi River has long been one of the great defining natural features of the United States. “Mississippi” is an Ojibwa (Chippewa) Indian word meaning “great river” or “gathering of waters.” The first recorded European to see the Mississippi River was Hernando de Soto, who led a Spanish expedition across the river in 1541. In their search for a Northwest Passage, Marquette and Joliet traveled on the river in 1673. Shortly after the Louisiana Purchase, while Lewis and Clark were leading the Corps of Discovery up the Missouri River and to the Pacific Ocean, U.S. Army Lieutenant Zebulon Pike was leading a military reconnaissance expedition up the Mississippi River in the summer of 1805. Later, during the steamboat era of the 1800s, Samuel Clemens traveled the river and began writing his impressions of steamboating and river life under the pen name of Mark Twain. In addition to the rich history and culture surrounding the Mississippi River, the length of the river and the extent of its basin are exceptional and part of the river’s uniqueness. It is one of the world’s largest rivers in terms of both length and basin size. The basin encompasses almost half the area of the continental United States and contains many different ecosystems, climate zones, and land uses. Several of the Mississippi’s tributaries, such as the Arkansas, Missouri, Ohio, White, and Wisconsin Rivers, are large rivers themselves. Given the Mississippi River’s value as a transportation corridor, the development and maintenance of a navigable river channel has long been a primary focus of commercial navigators and the U.S. government. The U.S. Army Corps of Engineers began its efforts on channel improvements vii 

viii PREFACE and snag removals in the 1800s, and in the 1930s the Corps constructed the locks and dams on the upper Mississippi River that support the current 9-foot minimum channel depth for navigation on the upper river. Further downstream, the Corps of Engineers has been involved in many other river control and channel maintenance activities, including the construction and maintenance of large Mississippi River levees and the Old River Control Structure at the divergence of the Atchafalaya and Mississippi Rivers. In contrast to the long-standing efforts to control the Mississippi River for navigation and flood management, concerns about water quality in the Mississippi River are more recent. The Clean Water Act of 1972 and its subsequent amendments have been the driving forces of efforts over the past three decades to monitor, characterize, and take steps to improve water quality in the Mississippi River. The Clean Water Act has resulted in many improvements in Mississippi River water quality. Many point source discharges of liquid and solid pollutants to the river, such as municipal sewage systems and industrial plants, have been brought under control through regulated effluent limits, resulting in marked improvements in water quality. During the 35 years of Clean Water Act implementation, the focus of activity has been on point source discharges through the issuance and monitoring of discharge permits. Diffuse, nonpoint sources such as runoff from urban and agricultural lands have received much less atten- tion. These sources contribute nutrients, sediments, toxic substances, and other materials to the river and have proven more challenging to control than point sources. The 10 states along the Mississippi River corridor differ in the extent to which they have focused on monitoring and assessing water quality in the Mississippi River compared to other waterbodies within their states. For the most part, their Clean Water Act implementation efforts have focused on streams and rivers contained entirely within state borders. Large interstate rivers such as the Mississippi present special challenges for effective Clean Water Act implementation. Long-standing and growing concerns of a number of groups about lack of coordination among states in implementing Clean Water Act provisions for protection and improvement of water quality in the Mississippi River prompted the McKnight Foundation of Minneapolis, Minnesota, to request the National Research Council (NRC) to undertake a study of the issue. The Committee on the Mississippi River and the Clean Water Act was ap- pointed in 2005 by the NRC and conducted its deliberations and its report production in response to the Statement of Task in Box 1-1. The committee examined how effectively the Clean Water Act has been applied in terms of protecting and restoring the water quality of the Mississippi River and how its provisions might be used even more fully. The committee did not undertake an examination of the adequacy of the 

PREFACE ix law itself. All discussions and investigations were conducted in the context of the existing Clean Water Act, with the presumption that it will not be changed substantively in the foreseeable future. The committee held meetings in 2005 and 2006 in four cities along the Mississippi River: Minneapolis, Dubuque, St. Louis, and Baton Rouge. The committee also convened one meeting at the National Academies offices in Washington, D.C. These meetings included presentations by representatives from universities, federal and state agencies, regional stakeholder groups, and members of the public (Appendix A lists guest speakers invited to the committee’s meetings). In addition to oral presentations, written comments from many state agency and interest group representatives and the public were submitted and considered. These presentations and written submittals were of significant value to the committee and made clear that the water quality of the Mississippi River and the northern Gulf of Mexico is a scien- tific and public policy topic of great regional and national importance. I thank the members of the committee for their uniform commitment to the endeavor, their good cheer, and their diligent efforts. The committee brought considerable range and depth of experience and expertise to the task. Our interactions were rich and produced insights and recommenda- tions that we hope are valuable for Mississippi River water quality plan- ning. It was a privilege to work with this outstanding group. I also thank the NRC staff members for their dedication and careful work over the course of the study. Jeff Jacobs, senior staff officer with the Water Science and Technology Board (WSTB), helped keep the committee on task and on schedule. Jeff and I worked collaboratively to organize and guide the committee writing assignments, to compile and edit all written contributions for a coherent consensus report, and to ensure that the views and comments of all committee members were considered in developing the report. Jeff’s professional insights and his keen editing skills were most help- ful and much appreciated. The committee also was ably assisted by Anita Hall, WSTB senior program associate, who handled logistics for our meet- ings and various aspects of report draft production and dissemination. The committee is grateful to our sponsor, the McKnight Foundation, for financial and intellectual support of the project. We extend special thanks to Gretchen Bonfert, environment program director at the founda- tion, and to her colleague Ron Kroese. Gretchen and Ron were very helpful in suggesting experts and knowledgeable advocates to visit with our com- mittee, and they carefully followed committee activities by attending public sessions of all committee meetings. The McKnight Foundation has focused on water quality in the Mississippi River and the Gulf of Mexico as a fund- ing priority since 1992. Today, McKnight’s Water Quality Collaborative, a group of many different organizations along the 10-state river corridor, is working to build coalitions to help improve Mississippi River water 

 PREEFACE quality. The McKnight Foundation is to be commended for its vision and commitment in supporting a National Academies review of this important, complex, and sometimes controversial topic. This report was reviewed in draft form by individuals chosen for the breadth of their perspectives and technical expertise in accordance with procedures approved by the NRC’s Report Review Committee. The pur- pose of this independent review was to provide candid and critical com- ments to assist the institution in making its published re­port as sound as possible and to ensure that the report meets institutional standards for objectivity, evidence, and responsiveness to the study charge. Reviewer comments and the draft manuscript remain confidential to protect the integrity of the deliberative process. We thank the following individuals for their review of this report: Clifton J. Aichinger, Ramsey-Washington Metro Watershed District; William L. Andreen, University of Alabama; Paul L. Freedman, Limno-Tech, Inc.; Jerome B. Gilbert, consultant; Lynn R. Goldman, Johns Hopkins University; Robert H. Meade, consultant; Patricia E. Norris, Michigan State University; Leonard A. Shabman, Resources for the Future; Richard E. Sparks, National Great Rivers Research and Educa- tion Center; Robert R. M. Verchick, Loyola University, New Orleans; and Paul D. Zugger, Public Sector Consultants. Although the reviewers listed above provided constructive com­ments and suggestions, they were not asked to endorse the report’s conclusions and recommendations nor did they see the final draft of the report before its release. The review of this report was overseen by Dr. Frank H. Stillinger, Princeton University, and Dr. Patrick L. Brezonik, University of Minnesota. They were responsible for ensuring that an independent examination of this report was conducted in accordance with institutional procedures and that all review comments were carefully considered. Responsibility for this report’s final contents rests entirely with the authoring committee and the institution. The Mississippi River is a natural and economic resource of inestimable value to the nation. Its water quality affects people and ecosystems and is important to the future of the basin. There are many large-scale and com- plex challenges associated with Mississippi River water quality protection and restoration. Our committee has worked to consider how these chal- lenges can be addressed within the provisions of the Clean Water Act. We hope that our efforts provide useful advice in meeting the challenges sur- rounding effective implementation of the Clean Water Act and in enhancing the multiple uses of the Mississippi River for future generations. David A. Dzombak, Chair 

Contents SUMMARY 1 1 INTRODUCTION 13 Mississippi River Water Quality Issues, 17 Report Organization and Audience, 20 2 CHARACTERISTICS OF THE MISSISSIPPI RIVER SYSTEM 21 The Mississippi River Basin, 24 Historic Alterations of the Mississippi River System, 29 Mississippi River Water Quality, 35 Water Quality Impacts in the Gulf of Mexico, 56 Summary, 62 3 THE CLEAN WATER ACT 65 Origins of the Clean Water Act, 66 Federal Water Pollution Control Act Amendments of 1972, 68 State-Level Authority in Protecting Water Quality, 78 Interstate Water Quality Protection, 85 Summary, 94 4 IMPLEMENTING THE CLEAN WATER ACT ALONG THE MISSISSIPPI RIVER 97 The NPDES Program and Point Source Control on the Mississippi River, 98 Mississippi River Water Quality Standards, 104 xi 

xii CONTENTS Water Quality Data and Assessment for the Mississippi River, 114 The Status of TMDL Development Along the Mississippi River, 122 Nutrient Criteria and TMDLs for the Mississippi River, 126 Federal-State Cooperation in the Chesapeake Bay, 128 Summary, 135 5 EVALUATING MISSISSIPPI RIVER WATER QUALITY 138 Mississippi River Basin Structure, Hydrology, and Monitoring, 139 Federal and Regional Mississippi River Evaluations, 141 Monitoring Associated with Clean Water Act Objectives, 146 Status of and Prospects for Mississippi River Monitoring, 155 Summary, 163 6 AGRICULTURAL PRACTICES AND MISSISSIPPI RIVER WATER QUALITY 165 Tensions Between Agricultural Production and Water Quality, 166 Federal Agricultural Programs for Resource Conservation, 168 Key Pollutants and Strategies for Reducing Their Impacts, 172 Approaches for Reducing Nonpoint Source Inputs from Agricultural Lands, 177 Motivating Nonpoint Source Control in Agriculture, 184 Potential Impacts of Biofuels Production, 185 Summary, 187 7 COLLABORATION FOR WATER QUALITY IMPROVEMENT ALONG THE MISSISSIPPI RIVER CORRIDOR 190 Clean Water Act Coordination Needs on an Interstate River, 191 Cooperation on Interstate Rivers, 192 Cooperative Efforts Along the Mississippi River, 198 EPA Collaboration on the Mississippi River, 204 Cooperation Among Federal Agencies on the Mississippi River, 207 Summary, 210 REFERENCES 212 APPENDIXES A Guest Speakers at Committee Meetings 227 B Acronyms 229 C Biographical Information: Committee on the Mississippi River and the Clean Water Act 233