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Water clarity of the Colorado River—Implications for food webs and fish communities

November 1, 2016

The closure of Glen Canyon Dam in 1963 resulted in drastic changes to water clarity, temperature, and flow of the Colorado River in Glen, Marble, and Grand Canyons. The Colorado River is now much clearer, water temperature is less variable throughout the year, and the river is much colder in the summer months. The flow—regulated by the dam—is now less variable annually, but has larger daily fluctuations than during pre-dam times. All of these changes have resulted in a different fish community and different food resources for fish than existed before the dam was built. Recent monitoring of water clarity, by measuring turbidity, has helped scientists and river managers understand modern water-clarity patterns in the dam-regulated Colorado River. These data were then used to estimate pre-dam turbidity in the Colorado River in order to make comparisons of pre-dam and dam-regulated conditions, which are useful for assessing biological changes in the river over time. Prior to dam construction, the large sediment load resulted in low water clarity almost all of the time, a condition which was more favorable for the native fish community.

Citation Information

Publication Year 2016
Title Water clarity of the Colorado River—Implications for food webs and fish communities
DOI 10.3133/fs20163053
Authors Nicholas Voichick, Theodore A. Kennedy, David Topping, Ronald E. Griffiths, Kyrie Fry
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Fact Sheet
Series Number 2016-3053
Index ID fs20163053
Record Source USGS Publications Warehouse
USGS Organization Southwest Biological Science Center