O'Shaughnessy Dam
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The O'Shaughnessy Dam is a dam on the Tuolumne River in the Hetch Hetchy Valley of California's Sierra Nevada mountains. The dam is located at Template:Coor dms inside Yosemite National Park. It creates the Hetch Hetchy Reservoir. The dam provides water and electricity to the city of San Francisco and to farmers in the San Joaquin Valley. The power-generation facilities and transmission lines are concealed to protect the valley's famous scenery. The reservoir's capacity is 0.444 cubic kilometres (360,360 acre-feet).
The O'Shaughnessy Dam is quite near to Yosemite's western boundary, but the long, narrow, fingerlike reservoir stretches eastward for about 12.5 km (over 8 miles). Some of the former scenic beauty of the valley remains, though the fluctuating water level creates a conspicuous white band at the waterline.
The dam was proposed in 1903, when the city of San Francisco applied to the Department of the Interior for water rights in the area. The Sierra Club resisted for the next ten years. John Muir, its president and founder, declared, "Dam Hetch Hetchy! As well dam for water-tanks the people's cathedrals and churches, for no holier temple has ever been consecrated by the heart of man." The Raker Bill of 1913 settled the dispute in San Francisco's favor. Construction was completed in 1923. The dam then stood 111 metres (364 feet) high; its present height of 131 metres (430 feet) was achieved only later.
In 1987, the idea of razing the O'Shaughnessy gained an adherent from Don Hodel, then secretary of the Department of the Interior under President Ronald Reagan. Hodel called for a study of the effect of tearing down the dam. The National Park Service concluded that two years after draining the valley, grasses would cover most of its floor and within 10 years, clumps of cone-bearing trees and some oaks would take root. Within 50 years, vegetative cover would be complete except for exposed rocky areas: eventually a forest would grow, rather than the meadow being restored [1] (http://www.sierraclub.org/ca/hetchhetchy/nps_hh_restoration.pdf).
Some people, such as Carl Pope (Director of the Sierra Club, a frequent supporter of Democratic political candidates), stated that Hodel had political motives [2] (http://www.sierraclub.org/ca/hetchhetchy/undamming_hh_NovDec87.html). The imputed motive was to divide the environmental movement: to see residents of the strongly Democratic city of San Francisco coming out against an environmental issue. For example, the then mayor of San Francisco and supervisor for the county of San Francisco, Dianne Feinstein said in a Los Angeles Times story in 1987: "All this is for an expanded campground? ... It's dumb, dumb, dumb."
The Sierra Club is currently advocating removing the dam, but the city of San Francisco is resisting, because the reservoir is currently serving 2.4 million people, including parts of San Mateo County, Alameda County, and Silicon Valley. The cost of deconstructing the dam will be about 65 million dollars, which is a fraction of the 8 billion dollars needed to upgrade the water system of San Francisco.
External links
- Restore Hetch Hetchy web site (http://www.hetchhetchy.org)
- Technical details of the O'Shaughnessy (http://www.structurae.net/en/structures/data/str03663.php)
- San Francisco Public Utilities Commission, Department of Hetch Hetchy Water and Power (http://sfwater.org/orgDetail.cfm/MO_ID/20)