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Building sandbars in the Grand Canyon

June 3, 2015

In 1963, the U.S. Department of the Interior’s Bureau of Reclamation finished building Glen Canyon Dam on the Colorado River in northern Arizona, 25 kilometers upstream from Grand Canyon National Park. The dam impounded 300 kilometers of the Colorado River, creating Lake Powell, the nation’s second largest reservoir.

By 1974, scientists found that the downstream river’s alluvial sandbars were eroding because the reservoir trapped the fine sediment that replenished the deposits during annual floods. These sandbars are important structures for many kinds of life in and along the river.

Now, by implementing a new strategy that calls for repeated releases of large volumes of water from the dam, the U.S. Department of the Interior (DOI) seeks to increase the size and number of these sandbars. Three years into the "high-flow experiment" (HFE) protocol, the releases appear to be achieving the desired effect. Many sandbars have increased in size following each controlled flood, and the cumulative results of the first three releases suggest that sandbar declines may be reversed if controlled floods can be implemented frequently enough.

Publication Year 2015
Title Building sandbars in the Grand Canyon
DOI 10.1029/2015EO030349
Authors Paul E. Grams, John C. Schmidt, Scott A. Wright, David Topping, Theodore S. Melis, David M. Rubin
Publication Type Article
Publication Subtype Journal Article
Series Title Eos, Earth and Space Science News
Index ID 70158917
Record Source USGS Publications Warehouse
USGS Organization Southwest Biological Science Center