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Circular 1391

National Water-Quality Assessment Program

The Quality of Our Nation’s Waters

Ecological Health in the Nation’s Streams, 1993—2005

By Daren M. Carlisle, Michael R. Meador, Terry M. Short, Cathy M. Tate, Martin E. Gurtz, Wade L. Bryant, James A. Falcone, and Michael D. Woodside

Thumbnail of and link to report PDF (121 MB)Introduction

This report summarizes a national assessment of the ecological health of streams done by the U.S. Geological Survey’s (USGS) National Water-Quality Assessment Program (NAWQA). Healthy functioning stream ecosystems provide society with many benefits, including water purification, flood control, nutrient recycling, waste decomposition, fisheries, and aesthetics. The value to society of many of these benefits is substantial; for example, sportfishing in the United States generates an estimated annual economic output of $125 billion, including more than 1 million jobs (National Research Council, 2005; American Sportfishing Association, 2008). Continued monitoring and assessment of the Nation’s streams is needed to support informed decisions that will safeguard this important natural and economic resource.

The quality of streams and rivers is often assessed with measures of the chemical or physical properties of water. However, a more comprehensive perspective is obtained if resident biological communities are also assessed. Guidelines to protect human health and aquatic life have been established for specific physical and chemical properties of water and have become useful yardsticks with which to assess water quality. Biological communities provide additional crucial information because they live within streams for weeks to years and therefore integrate through time the effects of changes to their chemical or physical environment. In addition, biological communities are a direct measure of stream health—an indicator of the ability of a stream to support aquatic life. Thus, the condition of biological communities, integrated with key physical and chemical properties, provides a comprehensive assessment of stream health.

First posted July 10, 2013

For additional information contact:
National Water-Quality Assessment (NAWQA) Program
U.S. Geological Survey
413 National Center
Reston, VA 20192

This report is presented in Portable Document Format (PDF); the latest version of Adobe Reader or similar software is required to view it. Download the latest version of Adobe Reader, free of charge.

Suggested citation:

Carlisle, D.M., Meador, M.R., Short, T.M., Tate, C.M., Gurtz, M.E., Bryant, W.L., Falcone, J.A., and Woodside, M.D., 2013, The quality of our Nation’s waters—Ecological health in the Nation’s streams, 1993–2005: U.S. Geological Survey Circular 1391, 120 p.,




Chapter 1—Overview of Findings and Implications

Chapter 2—Stream Ecology Primer

Chapter 3—Approach to Assessing Biological Condition

Chapter 4—National Assessments of Physical and Chemical Factors that Influence Stream Health

Chapter 5—Biological-Condition Assessment

Chapter 6—Factors Associated with Diminished Biological Condition

References Cited


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