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 supplies the Hetch Hetchy Aqueduct.

The Hetch Hetchy Road drops into the valley at the O'Shaughnessy Dam, but all points east of there are roadless, and accessible only to hikers and equestrians.

History

The name "Hetch Hetchy" comes from a grass with edible seeds that grows in the valley, in the Native American Sierra Miwok language cite web| url=http://www.yosemite.ca.us/history/place_names_of_the_high_sierra/h.html#page_39 | title=Place Names of the High Sierra | accessdate=2006-09-09 | date=1926 | author=Farquhar, Francis P.] . It was first used in the English language by Joseph Screech, who in 1850 became the first European to enter the valley. Screech noted that Paiutes had inhabited Hetch Hetchy and still gathered seeds, roots and acorns in and around it. Acorns are indeed available in the valley, but rare elsewhere in the high country.

Charles F. Hoffmann of the California Geological Survey conducted the first survey of the valley, in 1867 cite web | url=http://www.yosemite.ca.us/history/notes_on_hetch-hetchy_valley.html | title=Notes on Hetch-Hetchy Valley | accessdate=2006-09-09 | date=1868 | author=Hoffman, C. F.] .

In 1906, after a major earthquake, San Francisco applied to the United States Department of the Interior to gain water rights to Hetch Hetchy. This provoked a seven-year environmental struggle with the Sierra Club, led by the environmentalist John Muir. Muir observed:

:"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." cite web | url=http://www.yosemite.ca.us/john_muir_writings/the_yosemite/chapter_16.html | title="The Yosemite" | accessdate=2006-09-09 | author=Muir, John | date=1912]

Proponents of the dam replied that the valley would be even more beautiful with a lake. Muir predicted (correctly) that this lake would deposit an unsightly ring around its perimeter, which would be visible at low water. Because the valley was within Yosemite National Park, an act of Congress was needed to start the project. The federal government ended the dispute in 1913, with the passage of the Raker Act, which permitted flooding of the valley. However, environmental groups (including the Sierra Club) now advocate removing the dam.

Construction of the dam was finished in 1923. Water from the dam serves 2.4 million Californians in San Francisco, San Mateo, and Alameda Counties, as well as some communities in the San Joaquin Valley, and generates electricity for San Francisco.

For more information on the controversial history of the dam and reservoir, see the O'Shaughnessy Dam article.

Geology

Like Yosemite Valley, Hetch Hetchy was also sculpted by glaciers as recently as 10,000 years ago. The more recent glacier there was larger than the one in the paleo-Yosemite Valley. Today the Hetch Hetchy area is drier.

On the upper portion of the valley, beyond the reservoir, there is evidence of relatively young lava flows. One recent flow formed the Little Devils Postpile which, as the name suggests, is a smaller version of the Devils Postpile near Mammoth Lakes to the southeast. Both formations are great examples of columnar basalt, a phenomenon that results from contraction of basaltic lava as it cools (forming hexagonal columns). Similar formations are found in the Giant's Causeway in Ireland, and the New Jersey Palisades in the United States, as well as other places throughout the world.

ee also

*Tuolumne River
*Grand Canyon of the Tuolumne
*O'Shaughnessy Dam
*San Francisco Water Department
*Yosemite National Park
*Timeline of environmental events
*Hetch Hetchy Railroad

References

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External links

* [http://www.sfmuseum.org/hetch/hetchy7.html#muir John Muir on Hetch Hetchy Dam]
* [http://www.hetchhetchy.org Restore Hetch Hetchy web site]
* [http://www.sierraclub.org/ca/hetchhetchy/ Sierra Club on Hetch Hetchy]
* [http://www.discoverhetchhetchy.org Discover Hetch Hetchy - Environmental Defense]
* [http://sfwater.org/orgDetail.cfm/MO_ID/20 San Francisco Public Utilities Commission, Department of Hetch Hetchy Water and Power]
* [http://137.227.241.37/cgi-bin/libcginw.cgi?100=hetch+hetchy&100=&100=&100= U.S. Geological Survey Hetch Hetchy images] - About 30 are available, from both before and after the construction of the dam.
* [http://thehive.modbee.com/?q=node/180 Hetch Hetchy Early Native American People's History]
* [http://hetchhetchy.water.ca.gov California Resources Agency Hetch Hetchy Restoration Study]