THE SCIENCE OF INSTREAM FLOWS
A Review of the Texas Instream Flow Program
THE NATIONAL ACADEMIES PRESS
THE NATIONAL ACADEMIES 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 panel responsible for the report were chosen for their special competences and with regard for appropriate balance.
Support for this study was provided by the Texas Water Development Board under Contract No. SLOC 2003-483-494. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author and do not necessarily reflect the views of the sponsor.
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Cover:Dolan Falls on the Devils River in Val Verde County, Texas. Photograph courtesy of Kirk Winemiller. Copyright 2005 by Kirk Winemiller. All rights reserved.
Copyright 2005 by the National Academy of Sciences. All rights reserved.
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THE NATIONAL ACADEMIES
Advisers to the Nation on Science, Engineering, and Medicine
TheNational Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Bruce M. Alberts is president of the National Academy of Sciences.
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TheNational Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy’s purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Bruce M. Alberts and Dr. Wm. A. Wulf are chair and vice chair, respectively, of the National Research Council.
COMMITTEE ON REVIEW OF METHODS FOR ESTABLISHING INSTREAM FLOWS FOR TEXAS RIVERS*
GAIL E. MALLARD, Chair,
U.S. Geological Survey, Westerly, Rhode Island
KENNETH L. DICKSON,
University of North Texas, Denton
THOMAS B. HARDY,
Utah State University, Logan
University of Texas, Austin
DAVID R. MAIDMENT,
University of Texas, Austin
JAMES B. MARTIN,
Western Resources Advocates, Boulder, Colorado
PATRICIA F. MCDOWELL,
University of Oregon, Eugene
BRIAN D. RICHTER,
The Nature Conservancy, Charlottesville, Virginia
GREGORY V. WILKERSON,
University of Wyoming, Laramie
KIRK O. WINEMILLER,
Texas A&M University, College Station
DAVID A. WOOLHISER,
U.S. Department of Agriculture, Agricultural Research Service (Retired), Fort Collins, Colorado
LAUREN E. ALEXANDER, Study Director
DOROTHY K. WEIR, Senior Program Assistant
Instream flow science is an evolving field that brings together aspects of hydrology and hydraulics, biology, physical processes and geomorphology, and water quality. Instream flow programs are being developed to answer the often politically-charged question, “how much water should be in the river?” To balance ecologic and economic uses of water, instream flow programs rely on scientific input within a legal, social, and policy context.
The act of combining science and policy into a coherent, operational instream flow program is a challenging task. Across the United States, municipalities, counties, and states grapple with issues of ensuring adequate water in times of high demand and low supply. Texas has developed a prospective instream flow program to address these challenges. With its range of river and ecosystem conditions, growing population, high demands on water and episodic water scarcity, Texas in many ways is a microcosm of instream flow challenges across the United States, and its instream flow program may serve as a template for other jurisdictions.
Our NRC committee was charged to evaluate the Texas Instream Flow program as described in the Texas Instream Flow Programmatic Work Plan (PWP) and the Technical Overview Document (TOD). This report is the result of the National Research Council’s (NRC) Committee on Review of Methods for Establishing Instream Flows for Texas Rivers review of the Texas instream flow program. We were asked to comment on a technical work that already had been prepared by scientists and engineers in the state agencies. (See http://www.twdb.state.tx.us for the full text of the documents). In addressing our charge, the committee resisted the temptation to produce an overly prescriptive report, as it was not our assignment to (re)design the Texas instream flow program or to write an instruction manual of how to conduct an instream flow study. A prescriptive approach, which could involve detailed recommendations about techniques and methods or even a rewrite of the technical documents, would not have been appropriate. Furthermore, an overhaul of these documents did not prove necessary because the state agencies set forth a proposal with most of the important elements of a comprehensive instream flow program. The committee’s review, instead, identifies missing parts and recommends bolstering the skeletal pieces of Texas’ proposed program.
In preparing this report, the committee benefited greatly from our conversations with Texas State agency personnel who helped us understand the background for the Texas instream flow program. Without exception, they were open and responsive to our queries about Texas water resources and the multiple demands on water in the state. State agency personnel also helped us gain a better understanding of how the PWP and the TOD were prepared, including the difficulties of producing a plan by three agencies with three different missions.
The committee felt it would be a disservice to the Texas state agencies if we neglected to comment on the need for clear and measurable goals and a discussion of implementation. Clear, measurable goals and pragmatic ways to achieve those goals are critical to a successful instream flow program. Goal setting is the realm of policy makers, stakeholders, and other decision makers, but scientists have an important role in setting goals of an instream flow program as well.
Implementation of instream flow recommendations in Texas occurs in a complex setting where there are multiple and competing needs for water. Means to implement instream flow recommendations are necessary to prevent wasted time and resources of conducting technical evaluations of hydrology, biology, physical processes, and water quality. Oftentimes, programmatic aspects of implementation are not directly tied to the technical pieces of an instream flow recommendation. However, programmatic aspects establish important legal and pragmatic boundaries for the instream flow scientific studies and, thus, are discussed in this report.
A variety of water resources stakeholders in Texas including river basin authorities, municipal agencies, the academic community, non-governmental organizations, agricultural interests, and other citizen groups helped us understand the importance of stakeholder involvement in setting instream flow goals and establishing instream flow recommendations. The committee held three of its four meetings in Texas. During the open sessions of these meetings we heard public comment on the state’s instream flow program; we learned that the public holds strong conviction on river management priorities. In all, the public participation experience of this committee in Texas, in keeping with experience in other parts of the country, underscored the import of stakeholder participation and a fair, open, transparent process for determining instream flow in Texas.
Because instream flow science is new and still evolving, we provide a short tutorial (Chapter 3) that reflects the most current thinking on the subject. Texas’ prospective and systematic plan for its instream flow program gives the state an opportunity to establish a benchmark instream flow program and make significant contributions to the science. Our
committee hopes that the findings and recommendations contained in this report will help the state and others realize this advancement.
We have many people to thank for their help over the course of this project and in the preparation of this report. The Texas agency personnel were incredibly supportive of our committee and its progress towards report completion. They were particularly instrumental in organizing and leading field trips for the committee to see and experience the beauty and complexities of Texas river ecosystems. We express appreciation to Barney Austin and Bill Mullican, Texas Water Development Board; Kevin Mayes, Texas Parks and Wildlife Department, and Doyle Mosier, Texas Commission on Environmental Quality; and the staff of Texas State University at San Marcos, Joanna Curran, Marshall Jennings, and Andrew Sansom. We also thank panel participants Mary Kelly, Richard Kiesling, Barbara Nickerson, Dianne Wassenich, and William West, Jr.; and other guest presenters Todd Chenoweth, Kevin Craig, Mark Fisher, Ronald Gertson, Myron Hess, Kenneth Kramer, Ren Lohoefener, Greg Rothe, and Kenny Saunders. The report and the study process would not have been possible without the hard work of NRC study director Lauren Alexander and project assistant Dorothy Weir. Finally, I would like to recognize my fellow committee members for their long hours and dedication to advancing the science and art of instream flows in Texas.
This report was reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise in accordance with the procedures approved by the NRC’s Report Review Committee. The purpose of this independent review is to provide candid and critical comments that will assist the institution in making its published report as sound as possible and to ensure the report meets institutional standards for objectivity, evidence, and responsiveness to the study charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process. We wish to thank the following individuals for their review of this report: David Ford, David Ford Consulting Engineers, Inc.; Jim Geringer, former Governor of Wyoming; Douglas James, National Science Foundation; Ronald Kaiser, Texas A&M University; Robert Milhous, U.S. Geological Survey; Bruce Rhoads, University of Illinois; Clair Stalnaker, U.S. Geological Survey (retired); and Peter Whiting, Case Western Reserve University.
Although the reviewers listed above have provided many constructive comments and suggestions, they were not asked to endorse the conclusions or recommendations, nor did they see the final draft of the report before its release. The review of this report was overseen by Kenneth Potter, University of Wisconsin. Appointed by the National Research Council, he was responsible for making certain that an independent examination of the