Analyzing results of reservoir drawdowns in the Northwest
During March 1992, the U.S. Army Corps of Engineers tested drawdowns of two reservoirs in Washington State as part of a plan to help salmon migrate. Analysis of the results will help determine if drawdowns are a viable long-term alternative in salmon recovery efforts in the Pacific Northwest. To test the effects of such a process, the Corps of Engineers Walla Walla, Washington, District completed a test drawdown of Little Goose and Lower Granite reservoirs. The Lower Granite Dam, completed in 1975, is about 30 miles downstream from Clarkston, Washington. Little Goose, which began operating in 1970, is another 30 miles downstream from Lower Granite. The Corps constructed both dams for navigation and hydroelectric generation. Each has a generating capacity of 930 MW. While the dams themselves exhibited no damage from the drawdowns, other structures in the area, including roadway and railroad embankments, piers, and boat docks, were damaged. Resident fish and bottom-dwelling organisms died as water levels dropped. The Corps announced it will not conduct another test draw-down in 1993. From this test, the Corps will prepare a supplemental EIS, complete with public comment opportunities, to establish its water management actions for 1993. The final decision on whether drawdowns are a viable long-term alternative to help the salmon is still many months away. A number of regional agencies will be called on to make that decision, using results from this test, and other salmon recovery efforts. In the meantime, river users will continue to search for ways to bolster the number of salmon in the Columbia and Snake rivers.
- OSTI ID:
- 5570408
- Journal Information:
- Hydro Review; (United States), Vol. 11:5; ISSN 0884-0385
- Country of Publication:
- United States
- Language:
- English
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Impacts of the Snake River drawdown experiment on fisheries resources in Little Goose and Lower Granite Reservoirs, 1992
Impacts of the Snake River drawdown experiment on fisheries resources in Little Goose and Lower Granite Reservoirs, 1992