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U.S. Geological Survey Circular 1282

Grand Canyon Monitoring and Research Center

The State of the Colorado River Ecosystem in Grand Canyon

A Report of the Grand Canyon Monitoring and Research Center 1991–2004

Edited by Steven P. Gloss, Jeffrey E. Lovich, and Theodore S. Melis


Thumbnail of and link to report PDF (6.9 MB)

This report is an important milestone in the effort by the Secretary of the Interior to implement the Grand Canyon Protection Act of 1992 (GCPA; title XVIII, secs. 1801–1809, of Public Law 102-575), the most recent authorizing legislation for Federal efforts to protect resources downstream from Glen Canyon Dam. The chapters that follow are intended to provide decision makers and the American public with relevant scientific information about the status and recent trends of the natural, cultural, and recreational resources of those portions of Grand Canyon National Park and Glen Canyon National Recreation Area affected by Glen Canyon Dam operations. Glen Canyon Dam is one of the last major dams that was built on the Colorado River and is located just south of the Arizona-Utah border in the lower reaches of Glen Canyon National Recreation Area, approximately 15 mi (24 km) upriver from Grand Canyon National Park (fig. 1). The information presented here is a product of the Glen Canyon Dam Adaptive Management Program (GCDAMP), a federally authorized initiative to ensure that the primary mandate of the GCPA is met through advances in information and resource management. The U.S. Geological Survey‘s (USGS) Grand Canyon Monitoring and Research Center (GCMRC) has responsibility for the scientific monitoring and research efforts for the program, including the preparation of reports such as this one.

  • This report is also available in print from:

    USGS Information Services, Box 25286,
    Federal Center, Denver, CO 80225
    telephone: 888 ASK-USGS; e-mail:

For additional information contact:
SBSC Staff, Southwest Biological Science Center
U.S. Geological Survey
2255 N. Gemini Drive
Flagstaff, AZ 86001

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:

Gloss, S.P., Lovich, J.E., and Melis, T.S., eds., 2005, The state of the Colorado River ecosystem in Grand Canyon: U.S. Geological Survey Circular 1282, 220 p.



Project Staff

Overview by Lara M. Schmit, Steven P. Gloss, and Christopher N. Updike

Chapter 1. Influence of Glen Canyon Dam Operations on Downstream Sand Resources of the Colorado River in Grand Canyon by Scott A. Wright, Theodore S. Melis, David J. Topping, and David M. Rubin

Chapter 2. Fishes of Grand Canyon by Steven P. Gloss and Lewis G. Coggins with text box by Jeffrey E. Lovich

Chapter 3. Climatic Fluctuations, Drought, and Flow in the Colorado River by Robert H. Webb, Richard Hereford, and Gregory J. McCabe

Chapter 4. Water Quality in Lake Powell and the Colorado River by William S. Vernieu, Susan J. Hueftle, and Steven P. Gloss

Chapter 5. Aquatic Ecology: the Role of Organic Matter and Invertebrates by Theodore A. Kennedy and Steven P. Gloss

Chapter 6. Riparian Vegetation and Associated Wildlife by Barbara E. Ralston with text box by Charles Drost

Chapter 7. Birds of the Colorado River in Grand Canyon; a Synthesis of Status, Trends, and Dam Operation Effects by Jennifer A. Holmes, John R. Spence, and Mark K. Sogge

Chapter 8. Debris Flows in Grand Canyon and the Rapids of the Colorado River by Robert H. Webb, Peter G. Griffiths, Christopher S. Magirl, and Thomas C. Hanks

Chapter 9. Recreation Use Values and Nonuse Values of Glen and Grand Canyons by John Loomis, Aaron J. Douglas, and David A. Harpman

Chapter 10. Status and Trends of Hydropower Production at Glen Canyon Dam by David A. Harpman and Aaron J. Douglas

Chapter 11. Cultural Resources in the Colorado River Corridor by Helen C. Fairley

Chapter 12. Recreational Values and Campsites in the Colorado River Ecosystem by Matt Kaplinski, Jeff Behan, Joseph E. Hazel, Jr., Roderic A. Parnell, and Helen C. Fairley

Chapter 13. Lessons from 10 Years of Adaptive Management in Grand Canyon by Jeffrey E. Lovich and Theodore S. Melis

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