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O’Shaughnessy Dam

Dam on Hetch Hetchy Reservoir, Tuolumne River in Yosemite NP, Sierra Nevada near Foresta, CA

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O'Shaughnessy Dam is a 430-foot (131 m) high concrete arch-gravity dam in Tuolumne County, California, in the United States. It impounds the Tuolumne River, forming the Hetch Hetchy Reservoir at the lower end of Hetch Hetchy Valley in Yosemite National Park, about 160 miles (260 km) east of San Francisco. The dam and reservoir are the source for the Hetch Hetchy Aqueduct, which provides water for over 2 million people in San Francisco and other municipalities of the west Bay Area. The dam is named for engineer Michael O'Shaughnessy, who oversaw its construction. Although San Francisco had sought Tuolumne River water as early as the 1890s, this project did not move forward until the disastrous earthquake and fire of 1906, which underscored the insufficiency of the existing water supply. The…

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Dam

Waterbodies

Hetch Hetchy Reservoir

Reservoir

Tuolumne River

River

O’Shaughnessy Dam