The South Feather Water & Power Agency has awarded a $20 million contract to Granite Construction Inc. to perform modifications at the Lost Creek Dam in California’s Strawberry Valley.
Per the contract, Granite Construction is to increase the Lost Creek’s spillway openings, raise its crest outside the spill section, reinforce the dam’s downstream face, increase protection at its plunge pool and replace a road.
Located on a tributary of the south fork to the Feather River, Lost Creek Dam is a constant-angle radial arch dam completed in 1924.
Analysis performed in the mid-2000s determined that SFWPA needed to modify the dam to meet the probable maximum flood design, and evolving safety requirements established by the Federal Energy Regulatory Commission and California Department of Water Resources‘ Division of Safety of Dams.
The dam’s crest height, spillway configuration, reservoir volume, annual storage curve and flood operation rules had all been developed prior to the project being licensed as part of the 120-MW South Feather hydropower project during the 1950s.
The proposed modifications and methods used to determine them were detailed in-full by Hydro Review magazine in 2016.
Granite Construction said it expects work on the project to be completed by Fall 2018.
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