Hetch Hetchy is a valley, a reservoir, and a water system in California in the United States. The glacial Hetch Hetchy Valley lies in the northwestern part of Yosemite National Park and is drained by the Tuolumne River. For thousands of years before the arrival of settlers from the United States in the 1850s, the valley was inhabited by Native Americans who practiced subsistence hunting-gathering. During the late 19th century, the valley was renowned for its natural beauty – often compared to that of Yosemite Valley – but also targeted for the development of water supply for irrigation and municipal interests. The controversy over damming Hetch Hetchy became mired in the political issues of the day. The law authorizing the dam passed Congress on December 7, 1913. In 1923, the O'Shaughnessy Dam was completed on the Tuolumne River, flooding the entire valley under the Hetch Hetchy Reservoir. The dam and reservoir are the centerpiece of the Hetch Hetchy Project, which in 1934 began to deliver water 167 miles (269 km) west to San Francisco and its client municipalities in the greater San Francisco Bay Area.
The Tuolumne River flows for 149 miles (240 km) through Central California, from the high Sierra Nevada to join the San Joaquin River in the Central Valley. Originating at over 8,000 feet (2,400 m) above sea level in Yosemite National Park, the Tuolumne drains a rugged watershed of 1,958 square miles (5,070 km2), carving a series of canyons through the western slope of the Sierra. While the upper Tuolumne is a fast-flowing mountain stream, the lower river crosses a broad, fertile and extensively cultivated alluvial plain. Like most other central California rivers, the Tuolumne is dammed multiple times for irrigation and the generation of hydroelectricity.
The San Francisco Public Utilities Commission (SFPUC) is a public agency of the City and County of San Francisco that provides water, wastewater, and electric power services to the city and an additional 1.9 million customers within three San Francisco Bay Area counties.
The Don Pedro Dam, since 1971 also known as the Old Don Pedro Dam, was a dam across the Tuolumne River in Tuolumne County, California. The structure still exists and is flooded underneath Don Pedro Reservoir, which is formed by the New Don Pedro Dam.
The Raker Act was an act of the United States Congress that permitted building of the O'Shaughnessy Dam and flooding of Hetch Hetchy Valley in Yosemite National Park, California. It is named for John E. Raker, its chief sponsor. The Act, passed by Congress in 1913 by the Wilson administration, specified that because the source of the water and power was on public land, no private profit could be derived from the development. The plan for damming the valley was fought for years by John Muir. Construction of the dam was finished in 1923.
Moccasin, an unincorporated community in Tuolumne County, California, is located at the intersection of State Route 49 and State Route 120. The community is sited on the shore of Moccasin Reservoir at the edge of Lake Don Pedro. The town is home to a State of California Resources Agency, Department of Fish and Game fish hatchery.
Lake McClure is a reservoir in the Sierra Nevada foothills of western Mariposa County, California, United States.
New Melones Lake is a reservoir on the Stanislaus River in the central Sierra Nevada foothills, within Calaveras County and Tuolumne County, California.
Cherry Creek is a large, swift-flowing stream in the Sierra Nevada mountain range, and is the largest tributary of the Tuolumne River. The creek is 44.6 miles (71.8 km) long measured to its farthest headwaters; the main stem itself is 27.7 miles (44.6 km) long, draining a watershed of 234 square miles (610 km2) in the Stanislaus National Forest. Part of the drainage also extends into the northwest corner of Yosemite National Park.
Cherry Lake is an artificial lake in the Stanislaus National Forest of Tuolumne County, California, U.S.A., about 25 miles (40 km) east of the city of Sonora. It is at an elevation of 4,700 feet (1,433 m) on the western side of the Sierra Nevada, and lies just outside the western boundary of Yosemite National Park. The lake has a capacity of 273,500 acre⋅ft (337,400,000 m3) and is formed by Cherry Valley Dam on Cherry Creek.
Lake Del Valle is a storage reservoir located 10 miles (16 km) southeast of Livermore, in Alameda County, California. It is within Del Valle Regional Park.
The Hetch Hetchy Railroad (HHRR) was a 68-mile (109 km) standard gauge Class III railroad constructed by the City of San Francisco to support the construction and expansion of the O'Shaughnessy Dam across Hetch Hetchy Valley.
Turlock Lake State Recreation Area is a regional park and recreation area at Turlock Reservoir in Stanislaus County, central California, United States.
The La Grange Dam is a masonry-gravity diversion dam on the Tuolumne River near La Grange, California. The dam was completed in 1893 by the Turlock Irrigation District and Modesto Irrigation District in an effort to divert water into their canal systems for local farmers.
New Don Pedro Dam, often known simply as Don Pedro Dam, is an earthen embankment dam across the Tuolumne River, about 2 miles (3.2 km) northeast of La Grange, in Tuolumne County, California. The dam was completed in 1971, after four years of construction, to replace the 1924 concrete-arch Don Pedro Dam.
Restore Hetch Hetchy is a US non-profit organization seeking to restore the Hetch Hetchy Valley in Yosemite National Park to its original condition.
The Modesto Irrigation District (MID) is a special-purpose district that provides irrigation and drinking water, and electrical service, to customers in the San Joaquin Valley within Stanislaus County, California.
O'Shaughnessy Dam is a 430-foot (131 m) high concrete arch-gravity dam in Tuolumne County, California, 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 two 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.
Moccasin Dam is a small dam on Moccasin Creek in Tuolumne County, California, in the town of Moccasin, west of Yosemite. It holds the Moccasin Reservoir. The dam, reservoir and associated hydroelectric power plant are part of the Hetch Hetchy Project, which provide water and power to the city of San Francisco. The dam is located near the junction of Highway 120 and Highway 49.
