Federal Bureau of Reclamation officials opened up turbines and bypass tubes in the Glen Canyon Dam in northern Arizona, unleashing a simulated flood designed to mimic a natural flood in the Colorado River and Grand Canyon ecosystems.
The simulated flood, which began Nov. 19, increased the Colorado River’s flow from 8,000 cubic feet per second downstream of the dam to 42,000 cubic feet per second. Reclamation officials created the flood for 22 hours, gradually increasing the river’s flow to 42,000 cubic feet per second and then gradually returning the flow to 8,000 cubic feet per second. The river remained above its normal flow for five days during the simulated flood.
U.S. Secretary of the Interior Ken Salazar said the goal of the flood was to wash away sediment that had accumulated 15 miles downstream of the dam, where the Paria River flows into the Colorado. Salazar said the flood will likely create new sedimentary beaches along the banks of the river while depositing other sediment into Lake Mead.
Federal officials last simulated a Glen Canyon flood in 2008. Before that, officials simulated the flood in 2004 and 1996. Salazar said Bureau of Reclamation officials will now flood the Colorado River once or twice per year.
National Park Service officials voiced wholehearted support for the frequent flooding of the river. Some Reclamation officials, however, expressed concern the frequent floods will diminish water resources and the Glen Canyon Dam’s ability to produce electricity. Critics also said the new sedimentary beaches will only be temporary and provide few if any environmental benefits.
James M. Taylor ([email protected]) is managing editor of Environment & Climate News.