Relief Dam is a rockfill dam on Summit Creek, a tributary of the Middle Fork Stanislaus River, in Tuolumne County, California. The dam is part of the Spring Gap-Stanislaus Hydroelectric Project, and is owned and operated by Pacific Gas and Electric (PG&E).[1] [2]
Completed in 1910, the dam stands 145feet above the riverbed and is 505feet long at the crest. Altogether it contains 136984yd3 of fill.[3] The dam forms Relief Reservoir, which has a storage capacity of 15122acre feet of water and a full surface area of 189acres. The drainage basin behind the dam totals 24.51mi2.[3]
The reservoir is primarily drawn down in the late summer and fall to supplement flows to the hydroelectric powerhouses at Donnells Dam and Beardsley Dam (part of the separate PG&E Tri-Dam Project) and others on the Stanislaus River.[2]