Hetch Hetchy Reservoir
Encyclopedia
Hetch Hetchy Reservoir is a reservoir in Yosemite National Park
, about 65 miles (104.6 km) northeast from the city of Merced, California
. The reservoir has a capacity of 360000 acre.ft and is formed by the 364 ft (110.9 m) concrete gravity O'Shaughnessy Dam
in Hetch Hetchy Valley
on the Tuolumne River
. After a years-long battle against the dam, led by John Muir
, the dam was approved under the administration of Woodrow Wilson
in 1913 and was completed in 1923. It is owned by the City and County of San Francisco. The primary purpose is to supply drinking water to the San Francisco Bay Area
. It is one of nine reservoirs in San Francisco's system and holds about 25% of its overall storage capacity. The water is transported from the reservoir by the Hetch Hetchy Aqueduct
. Hydroelectricity
is also produced by Kirkwood Powerhouse and Moccasin Powerhouse, which have a capacity of 118 and 100 megawatts
, respectively. Because Hetch Hetchy is a municipal water supply and its water is not filtered
, swimming and boating are prohibited. Fishing is permitted only from the lake shore.
Yosemite National Park
Yosemite National Park is a United States National Park spanning eastern portions of Tuolumne, Mariposa and Madera counties in east central California, United States. The park covers an area of and reaches across the western slopes of the Sierra Nevada mountain chain...
, about 65 miles (104.6 km) northeast from the city of Merced, California
Merced, California
Merced is a city in, and the county seat of, Merced County, California in the San Joaquin Valley of Northern California. As of the 2010 census, the city had a population of 78,958. Incorporated in 1889, Merced is a charter city that operates under a council-manager government...
. The reservoir has a capacity of 360000 acre.ft and is formed by the 364 ft (110.9 m) concrete gravity O'Shaughnessy Dam
O'Shaughnessy Dam
The O'Shaughnessy Dam is a curved gravity dam on the Tuolumne River in the Hetch Hetchy Valley of California's Sierra Nevada. The dam is located in Yosemite National Park, and creates the Hetch Hetchy Reservoir. It is named for former San Francisco chief engineer and the original chief engineer of...
in Hetch Hetchy Valley
Hetch Hetchy Valley
Hetch Hetchy Valley is a glacial valley in Yosemite National Park in California. It is currently completely flooded by O'Shaughnessy Dam, forming the Hetch Hetchy Reservoir. The Tuolumne River fills the reservoir. Upstream from the valley lies the Grand Canyon of the Tuolumne. The reservoir...
on the Tuolumne River
Tuolumne River
The Tuolumne River is a California river that flows nearly from the central Sierra Nevada to the San Joaquin River in the Central Valley...
. After a years-long battle against the dam, led by John Muir
John Muir
John Muir was a Scottish-born American naturalist, author, and early advocate of preservation of wilderness in the United States. His letters, essays, and books telling of his adventures in nature, especially in the Sierra Nevada mountains of California, have been read by millions...
, the dam was approved under the administration of Woodrow Wilson
Woodrow Wilson
Thomas Woodrow Wilson was the 28th President of the United States, from 1913 to 1921. A leader of the Progressive Movement, he served as President of Princeton University from 1902 to 1910, and then as the Governor of New Jersey from 1911 to 1913...
in 1913 and was completed in 1923. It is owned by the City and County of San Francisco. The primary purpose is to supply drinking water to the San Francisco Bay Area
San Francisco Bay Area
The San Francisco Bay Area, commonly known as the Bay Area, is a populated region that surrounds the San Francisco and San Pablo estuaries in Northern California. The region encompasses metropolitan areas of San Francisco, Oakland, and San Jose, along with smaller urban and rural areas...
. It is one of nine reservoirs in San Francisco's system and holds about 25% of its overall storage capacity. The water is transported from the reservoir by the Hetch Hetchy Aqueduct
Hetch Hetchy Aqueduct
The Hetch Hetchy Aqueduct is a conveyance of Tuolumne River water runoff from federal lands in Yosemite National Park to San Francisco and its client municipalities in the greater San Francisco Bay Area...
. Hydroelectricity
Hydroelectricity
Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy...
is also produced by Kirkwood Powerhouse and Moccasin Powerhouse, which have a capacity of 118 and 100 megawatts
Watt
The watt is a derived unit of power in the International System of Units , named after the Scottish engineer James Watt . The unit, defined as one joule per second, measures the rate of energy conversion.-Definition:...
, respectively. Because Hetch Hetchy is a municipal water supply and its water is not filtered
Filter (water)
A water filter removes impurities from water by means of a fine physical barrier, a chemical process or a biological process. Filters cleanse water to various extents for irrigation, drinking water, aquariums, and swimming pools.-Methods of filtration:...
, swimming and boating are prohibited. Fishing is permitted only from the lake shore.