Salt Lake City - The Bureau of Reclamation today released a final environmental assessment (FEA) and a Finding of No Significant Impact (FONSI) that authorizes the initiation of an early-March 2008 high-flow test and fall steady flow experiment from Glen Canyon Dam downstream through the Grand Canyon. The FEA provides an evaluation of the environmental effects of the proposed action and no action, in compliance with the National Environmental Policy Act of 1969.
The FEA evaluates the impact of the proposed experimental flows on a wide range of environmental and socioeconomic resources. Following release of these documents, the high-flow experiment and associated research activities will be undertaken on March 4th cooperatively by scientists and resource managers from Interior's U.S. Geological Survey (USGS), Reclamation, National Park Service, U.S. Fish and Wildlife Service, and Bureau of Indian Affairs.
The 2008 high flow test will be similar to the previous high flow experiments conducted by the joint Interior agencies in 2004, but the amount of sediment available for the 2008 experiment is considerably larger. Based on the previous experiments, scientists have concluded that more sand is needed to rebuild sandbars throughout the 277-mile reach of Grand Canyon National Park than was available in 1996 or 2004. Currently, sand supplies in the river are at a 10-year high with a volume about three times greater than in 2004 due to tributary inflows below the dam over the past 16 months.
During the high-flow experiment, Reclamation will release water through Glen Canyon Dam's powerplant and bypass tubes to a maximum amount of approximately 41,500 cubic feet per second (cfs) for about 60 hours. Current operational plans call for the experimental flows to begin increasing in the evening on March 4th, with powerplant bypass flows to begin on March 5th.
From February 8-22, 2008, Reclamation solicited public comments on the environmental assessment. The final environmental assessment and FONSI conclude that implementation of the preferred alternative — the March 2008 high-flow test and fall steady flow experiment from Glen Canyon Dam — would have no significant impacts on the quality of the human environment or the natural resources below the dam.
The FEA and FONSI are available for review at: www.usbr.gov/uc/envdocs/ea/gc/2008hfe/index.html
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