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.
After 1900, California continued to grow rapidly and soon became an agricultural and industrial power. The economy was widely based on specialty agriculture, oil, tourism, shipping, film, and after 1940 advanced technology such as aerospace and electronics industries – along with a significant military presence. The films and stars of Hollywood helped make the state the "center" of worldwide attention. California became an American cultural phenomenon; the idea of the "California Dream" as a portion of the larger American Dream of finding a better life drew 35 million new residents from the start to the end of the 20th century (1900–2010). Silicon Valley became the world's center for computer innovation.
Don Pedro Reservoir, also known as Lake Don Pedro, is a reservoir formed by the construction of the New Don Pedro Dam across the Tuolumne River in Tuolumne County, California, United States.
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 Stanislaus River is a tributary of the San Joaquin River in north-central California in the United States. The main stem of the river is 96 miles (154 km) long, and measured to its furthest headwaters it is about 150 miles (240 km) long. Originating as three forks in the high Sierra Nevada, the river flows generally southwest through the agricultural San Joaquin Valley to join the San Joaquin south of Manteca, draining parts of five California counties. The Stanislaus is known for its swift rapids and scenic canyons in the upper reaches, and is heavily used for irrigation, hydroelectricity and domestic water supply.
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.
New Spicer Meadow Reservoir is a reservoir in the Sierra Nevada, within the Stanislaus National Forest in eastern 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 40 miles (64 km) long measured to its farthest headwaters; the main stem itself is 26 miles (42 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.
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 Mokelumne Aqueduct is a 95-mile (153 km) water conveyance system in central California, United States. The aqueduct is supplied by the Mokelumne River and provides water to 35 municipalities in the East Bay in the San Francisco Bay Area. The aqueduct and the associated dams, pipelines, treatment plants and hydroelectric system are owned and operated by the East Bay Municipal Utility District (EBMUD) and provide over 90 percent of the water used by the agency.
The La Grange Dam is a masonry-gravity diversion dam on the Tuolumne River near La Grange, California. The dam was completed in 1883 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.
Donnells Dam is a concrete arch dam located on the Middle Fork of the Stanislaus River in Tuolumne County, California. The water impounded by the 291-foot (89 m) high dam forms Donnell Lake in Stanislaus National Forest. The dam and reservoir are co-owned by the Oakdale Irrigation District and South San Joaquin Irrigation District, and the dam is one of three in the Tri-Dam Project. The other two dams in the project are Beardsley Dam and Tulloch Dam.
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.
