Hetch Hetchy Valley is a
glacialA glacier is a perennial mass of ice which moves over land. A glacier forms in locations where the mass accumulation of snow and ice exceeds ablation over many years...
valleyIn geology, a valley or dale is a depression with predominant extent in one direction. A very deep river valley may be called a canyon or gorge.The terms U-shaped and V-shaped are descriptive terms of geography to characterize the form of valleys...
in
Yosemite National ParkYosemite National Park is a 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...
in
CaliforniaCalifornia is the most populous state in the United States, and the third largest by area. California is the second most populous sub-national entity in the Americas, behind only São Paulo, Brazil...
. It is currently completely flooded by
O'Shaughnessy DamThe 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...
, forming the
Hetch Hetchy ReservoirHetch Hetchy Reservoir is a reservoir in Yosemite National Park, about northeast from the city of Merced, California. The reservoir has a capacity of and is formed by the concrete gravity O'Shaughnessy Dam in Hetch Hetchy Valley on the Tuolumne River...
. The
Tuolumne RiverThe Tuolumne River in the U.S. state of California flows nearly from the central Sierra Nevada into the San Joaquin River in the Central Valley. Beginning at almost in elevation in Yosemite National Park, the river flows west through deep canyons before spilling into the foothills of the Sierra...
fills the reservoir. Upstream from the valley lies the
Grand Canyon of the TuolumneThe Grand Canyon of the Tuolumne is the portion of the valley of the Tuolumne River in Yosemite National Park, USA. As defined by the United States Geological Survey, it begins immediately below Tuolumne Meadows and ends immediately above Hetch Hetchy Valley.The Tuolumne River runs as a somewhat...
. The reservoir supplies the
Hetch Hetchy AqueductThe 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...
. The damming of the valley in the 1920s, and the creation of a reservoir, were at the time, and since, a major environmental controversy in the Western United States.
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.
The name "Hetch Hetchy" comes from a grass with edible seeds that grows in the valley, in the
Native AmericanNative Americans in the United States is the phrase that describes indigenous peoples from North America now encompassed by the continental United States, including parts of Alaska and the island state of Hawaii. They comprise a large number of distinct tribes, states, and ethnic groups, many of...
Sierra MiwokThe Plains and Sierra Miwok , were the largest group of Miwok Native American people...
language .
Hetch Hetchy Valley is a
glacialA glacier is a perennial mass of ice which moves over land. A glacier forms in locations where the mass accumulation of snow and ice exceeds ablation over many years...
valleyIn geology, a valley or dale is a depression with predominant extent in one direction. A very deep river valley may be called a canyon or gorge.The terms U-shaped and V-shaped are descriptive terms of geography to characterize the form of valleys...
in
Yosemite National ParkYosemite National Park is a 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...
in
CaliforniaCalifornia is the most populous state in the United States, and the third largest by area. California is the second most populous sub-national entity in the Americas, behind only São Paulo, Brazil...
. It is currently completely flooded by
O'Shaughnessy DamThe 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...
, forming the
Hetch Hetchy ReservoirHetch Hetchy Reservoir is a reservoir in Yosemite National Park, about northeast from the city of Merced, California. The reservoir has a capacity of and is formed by the concrete gravity O'Shaughnessy Dam in Hetch Hetchy Valley on the Tuolumne River...
. The
Tuolumne RiverThe Tuolumne River in the U.S. state of California flows nearly from the central Sierra Nevada into the San Joaquin River in the Central Valley. Beginning at almost in elevation in Yosemite National Park, the river flows west through deep canyons before spilling into the foothills of the Sierra...
fills the reservoir. Upstream from the valley lies the
Grand Canyon of the TuolumneThe Grand Canyon of the Tuolumne is the portion of the valley of the Tuolumne River in Yosemite National Park, USA. As defined by the United States Geological Survey, it begins immediately below Tuolumne Meadows and ends immediately above Hetch Hetchy Valley.The Tuolumne River runs as a somewhat...
. The reservoir supplies the
Hetch Hetchy AqueductThe 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...
. The damming of the valley in the 1920s, and the creation of a reservoir, were at the time, and since, a major environmental controversy in the Western United States.
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 AmericanNative Americans in the United States is the phrase that describes indigenous peoples from North America now encompassed by the continental United States, including parts of Alaska and the island state of Hawaii. They comprise a large number of distinct tribes, states, and ethnic groups, many of...
Sierra MiwokThe Plains and Sierra Miwok , were the largest group of Miwok Native American people...
language . 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. HoffmannCharles Frederick Hoffmann was a German-American topographer working in California U.S. from 1860 to 1880.-Life:Hoffmann was born in Frankfurt, Germany, 1838. After receiving an education in engineering, he emigrated to America. In 1857 he was topographer for Frederick Lander’s survey to the Rocky...
of the
California Geological SurveyAlthough it was not until 1880 that the California State Mining Bureau, predecessor to the California Geological Survey, was established, the "roots" of California's state geological survey date to an earlier time...
conducted the first survey of the valley, in 1867 .
In 1906, after
a major earthquakeThe San Francisco earthquake of 1906 was a major earthquake that struck San Francisco, CA and the coast of Northern California at 5:12 A.M. on Wednesday, April 18, 1906. The most widely accepted estimate for the magnitude of the earthquake is a moment magnitude of 7.8; however, other values have...
, San Francisco applied to the
United States Department of the InteriorThe United States Department of the Interior is the United States federal executive department of the U.S. government responsible for the management and conservation of most federal land and the administration of programs relating to Native Americans, Alaska Natives, and Native Hawaiians, and to...
to gain water rights to Hetch Hetchy. This provoked a seven-year
environmentalThe natural environment, commonly referred to simply as the environment, is a term that encompasses all living and non-living things occurring naturally on Earth or some region thereof....
struggle with the environmental group
Sierra ClubThe Sierra Club is the oldest and largest grassroots environmental organization in the United States. It was founded on May 28, 1892 in San Francisco, California by the well-known conservationist and preservationist John Muir, who became its first president...
, led by
John MuirJohn Muir was a Scottish-born American naturalist, author, and early advocate of preservation of U.S. wilderness. His letters, essays, and books telling of his adventures in nature, especially in the Sierra Nevada mountain range of California, have been read by millions and are still popular today...
. 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.
Proponents of the dam replied that the valley would be even more beautiful with a lake. Muir correctly predicted 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 ParkYosemite National Park is a 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...
, an act of
CongressThe United States Congress is the bicameral legislature of the federal government of the United States of America, consisting of two houses, the Senate and the House of Representatives. Both senators and representatives are chosen through direct election....
was needed to start the project. The federal government ended the dispute in 1913, with the passage of the
Raker ActThe 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. The Act, passed by Congress in 1913 by the Wilson administration, specified that because the source of the water and...
, which permitted flooding of the valley.
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. Environmental groups (including the Sierra Club) advocate removing the dam.
For more information on the controversial history of the dam and reservoir, see the
O'Shaughnessy DamThe 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...
article.
Geology
Like
Yosemite ValleyYosemite Valley is a world-famous scenic location in the Sierra Nevada mountains of California. It is the centerpiece of Yosemite National Park, attracting visitors from all parts of the globe....
, 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
lavaLava is molten rock expelled by a volcano during eruption. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at temperatures from 700 °C to 1,200 °C...
flows. One recent flow formed the
Little Devils PostpileLittle Devils Postpile, in Yosemite National Park in California, United States, is a set of columnar joints in a basalt plug resembling the Devils Postpile formation. It is located along the Tuolumne River a few miles west of Tuolumne Meadows....
which, as the name suggests, is a smaller version of the Devils Postpile near
Mammoth LakesMammoth Lakes is a town in Mono County, California, the county's only incorporated community. It is located northwest of Mount Morrison, at an elevation of...
to the southeast. Both formations are great examples of columnar basalt, a phenomenon that results from contraction of
basaltBasalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey.On Earth, most...
ic lava as it cools (forming
hexagonIn geometry, a hexagon is a polygon with six edges and six vertices. A regular hexagon has Schläfli symbol {6}.- Regular hexagon :The internal angles of a regular hexagon are all 120° and the hexagon has 720 degrees T. It has 6 rotational symmetries and 6 reflection symmetries, making up the...
al columns). Similar formations are found in the
Giant's CausewayThe Giant's Causeway is an area of about 40,000 interlocking basalt columns, the result of an ancient volcanic eruption. It is located in County Antrim, on the northeast coast of Northern Ireland, about two miles north of the town of Bushmills...
in Ireland, and the
New Jersey PalisadesThe Palisades, also called the New Jersey Palisades or the Hudson Palisades are a line of steep cliffs along the west side of the lower Hudson River in northeast New Jersey and southern New York in the United States. The cliffs stretch north from Jersey City approximately 20 mi to near Nyack, New...
in the United States, as well as other places throughout the world.
See also
- Tuolumne River
The Tuolumne River in the U.S. state of California flows nearly from the central Sierra Nevada into the San Joaquin River in the Central Valley. Beginning at almost in elevation in Yosemite National Park, the river flows west through deep canyons before spilling into the foothills of the Sierra...
- Grand Canyon of the Tuolumne
The Grand Canyon of the Tuolumne is the portion of the valley of the Tuolumne River in Yosemite National Park, USA. As defined by the United States Geological Survey, it begins immediately below Tuolumne Meadows and ends immediately above Hetch Hetchy Valley.The Tuolumne River runs as a somewhat...
- 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...
- San Francisco Water Department
The San Francisco Water Department is an agency in San Francisco that provides water service to residents of the San Francisco Bay Area. The San Francisco Water Department privately holds substantial amounts of undeveloped land in many parts of the San Francisco Bay Area.Since the mid-19th century...
- Yosemite National Park
Yosemite National Park is a 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...
- Timeline of environmental events
The timeline lists geological, astronomical, and climatological events in relation to events in human history which they influenced. For the history of humanity's perspective on these events, see timeline of the history of environmentalism.-10th millennium BC:...
- Hetch Hetchy Railroad
The Hetch Hetchy Railroad was a 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....
- The National Parks: America's Best Idea
The National Parks: America's Best Idea is a 2009 documentary film for television, DVD and companion book by director/producer Ken Burns and producer/writer Dayton Duncan which features the United States National Park system and traces the system's history...
External links