Flagstaff, Ariz. —Resources along the Colorado River in Glen Canyon National Recreation Area and Grand Canyon National Park generally benefited from a high-flow experiment conducted in March 2008 from Glen Canyon Dam, near Page, Ariz., according to research findings released today by the U.S. Geological Survey.
The 2008 experiment, designed to mimic natural pre-dam flooding, tested the ability of high flows to rebuild eroded Grand Canyon sandbars, create habitat for the endangered humpback chub, and benefit other resources such as archaeological sites, rainbow trout, aquatic food for fish, and riverside vegetation.
Before the dam’s completion in 1963, spring snowmelt produced floods that carried large quantities of sand that created and maintained Grand Canyon Sandbars. Today, because Glen Canyon Dam, which provides hydropower to customers in six States, traps approximately 90 percent of the sand once available to maintain Grand Canyon sandbars, high flows are the only way to rebuild these important resources.
The studies’ key findings follow:
“Insights gained about the effects of the 2008 experiment will be invaluable in helping decision makers determine the best frequency, timing, duration, and magnitude for future high flows to benefit resources in Glen Canyon National Recreational Area and Grand Canyon National Park,” noted John Hamill, Chief of the USGS Grand Canyon Monitoring and Research Center.
On March 5, 2008, the Bureau of Reclamation began a 60-hour high-flow experiment at Glen Canyon Dam. Water was released through the dam’s powerplant and bypass tubes to a peak of about 41,500 cubic feet per second, about twice the normal peak. Two previous experiments were conducted in 1996 and 2004.
Research completed by the U.S. Geological Survey and cooperating scientists about the effects of the 2008 high-flow experiment will be discussed at the Glen Canyon Dam Adaptive Management Program meeting February 3–4, 2010, in Phoenix, Ariz. The findings will also be taken into consideration in development of a new protocol for conducting additional high-flow experiments, announced by Secretary Salazar in December 2009.
The USGS Southwest Biological Science Center's Grand Canyon Monitoring and Research Center is responsible for scientific research and monitoring activities for the Glen Canyon Dam Adaptive Management Program, which is administered by the U.S. Department of the Interior. Research activities are undertaken in close cooperation with a wide range of federal, State, and tribal resource management agencies; academic institutions; and private consultants.
A USGS Fact Sheet summarizing the results of the 2008 high-flow experiment is available online.
USGS provides science for a changing world. For more information, visit www.usgs.gov.
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