A draft feasibility study could be released in spring 2009 on a proposal to increase the height of California’s 710-MW Shasta Dam, increasing migratory fish survival, improving water supply, and increasing hydropower generation.
The Bureau of Reclamation completed a series of geologic surveys earlier this year. The test pit and drill-hole investigations provide data to evaluate bedrock and soil conditions at 30 sites along Shasta Dam, Bridge Bay Marina, and Lakeshore Drive, on the upper Sacramento River near Redding, Calif.
A BuRec geologist said engineers would use the survey information when developing project designs. The information also would be used when determining cost estimates, which are expected to be included in the draft feasibility study on the dam expansion project. A final feasibility report and environmental impact statement could be completed in 2010.
Scenarios under consideration call for increasing the dam’s height by 6.5 feet, 12.5 feet, or 18.5 feet. A higher dam would expand the capacity of Shasta Reservoir, which is expected to increase survival of anadromous fish populations in the upper Sacramento River, improve water supply reliability, and increase hydroelectric generation from higher head.
BuRec’s Mid-Pacific Region began in 2000 to evaluate the potential for enlarging Shasta Dam. It cited increased demand for water supplies and attention to ecosystem needs in California’s Central Valley as reasons for pursuing the study.
BuRec completed construction of the 602-foot-tall dam and 4.55-million-acre-foot reservoir in 1945. It operates the project in conjunction with other facilities to provide flood control, water supply, hydropower generation, fish and wildlife conservation, and maintenance of navigation flows.