Hetch Hetchy Valley(redirected from Hetch Hetchy Canyon)
Hetch Hetchy Valley,in Yosemite National ParkYosemite National Park
, 748,436 acres (302,881 hectares), E central Calif.; est. 1890 as a result of the efforts of conservationist John Muir. Located in the Sierra Nevada, it is a glacier-scoured area of great beauty; Mt. Lyell (13,114 ft/3,997 m) is the highest peak.
..... Click the link for more information. , central Calif., on the Tuolumne River. It once rivaled Yosemite Valley in beauty and grandeur. O'Shaughnessy Dam (completed 1923; enl. 1938) turned the valley into a lake c.9 mi (14 km) long, which is used for generating power and for supplying water to San Francisco by an aqueduct 156 mi (251 km) long.