Relief Dam

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).

Completed in 1910, the dam stands 145 ft above the riverbed and is 505 ft long at the crest. Altogether it contains 136984 yd3 of fill. The dam forms Relief Reservoir, which has a storage capacity of 15122 acre feet of water and a full surface area of 189 acre. The drainage basin behind the dam totals 24.51 mi2.

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.