Hells Canyon Dam is a concrete gravity

dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, a ...

in the

western Western may refer to: Places *Western, Nebraska, a village in the US *Western, New York, a town in the US *Western Creek, Tasmania, a locality in Australia *Western Junction, Tasmania, a locality in Australia *Western world, countries that id ...

United States, on the

Snake River The Snake River is a major river of the greater Pacific Northwest region in the United States. At long, it is the largest tributary of the Columbia River, in turn, the largest North American river that empties into the Pacific Ocean. The Snake ...

Hells Canyon Hells Canyon is a canyon in the Western United States, located along the border of eastern Oregon, a small section of eastern Washington and western Idaho. It is part of the Hells Canyon National Recreation Area which is also located in p ...

along the

Idaho Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and Wyom ...

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

border. At

river mile A river mile is a measure of distance in miles along a river from its mouth. River mile numbers begin at zero and increase further upstream. The corresponding metric unit using kilometers is the river kilometer. They are analogous to vehicle road ...

247, the dam impounds Hells Canyon Reservoir; its spillway

elevation The elevation of a geographic location is its height above or below a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface (see Geodetic datum § Vert ...

is above

sea level Mean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardised g ...

. It is the third and final

hydroelectric Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined and ...

dam of the Hells Canyon Project, which includes

Brownlee Dam Brownlee Dam is a hydroelectric earth fill embankment dam in the western United States, on the Snake River along the Idaho-Oregon border. In Hells Canyon at river mile 285, it impounds the Snake River in the Brownlee Reservoir. It is part of ...

(1959) and

Oxbow Dam Oxbow Dam is a Hydroelectricity, hydroelectric run-of-the-river hydroelectricity, run-of-the-river rockfill dam in the Western United States, western United States, on the Snake River in Hells Canyon (river mile 273) along the Idaho-Oregon border. ...

(1961), all built and operated by

Idaho Power Company Idaho Power Company (IPC) is a regulated electrical power utility. Its business involves the purchase, sale, generation, transmission and distribution of electricity in eastern Oregon and southern Idaho. It is a subsidiary of IDACORP, Inc. The c ...

. The Hells Canyon Complex on the Snake River is the largest privately owned hydroelectric power complex in the nation, according to the US Energy Information Administration. The contractor for the Hells Canyon Dam was Morrison-Knudsen of

Boise Boise (, , ) is the capital and most populous city of the U.S. state of Idaho and is the county seat of Ada County. On the Boise River in southwestern Idaho, it is east of the Oregon border and north of the Nevada border. The downtown area's ...

. The Hells Canyon Dam powerhouse contains three generating units, with a total

nameplate capacity Nameplate capacity, also known as the rated capacity, nominal capacity, installed capacity, or maximum effect, is the intended full-load sustained output of a facility such as a power station,

of . Power generation began with two units in 1967, the third came on line the following year. Lacking passage for migrating

salmon Salmon () is the common name for several list of commercially important fish species, commercially important species of euryhaline ray-finned fish from the family (biology), family Salmonidae, which are native to tributary, tributaries of the ...

, the three dams of the Hells Canyon Project blocked access by

anadromous Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousan ...

salmonids to a stretch of the Snake River

drainage basin A drainage basin is an area of land where all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, t ...

from Hells Canyon Dam up to

Shoshone Falls Shoshone Falls () is a waterfall in the western United States, on the Snake River in south-central Idaho, approximately northeast of the city of Twin Falls. Sometimes called the "Niagara of the West," Shoshone Falls is in height, higher than ...

, which naturally prevents any upstream fish passage to the upper Snake River basin.

High dam proposal

As built, Hells Canyon Dam is significantly lower than it was originally proposed in the 1940s, with three dams (Hells Canyon, Brownlee Dam and Oxbow Dam) taking the place of a single high dam. As proposed by the

U.S. Army Corps of Engineers , colors = , anniversaries = 16 June (Organization Day) , battles = , battles_label = Wars , website = , commander1 = ...

, the Hells Canyon High Dam would have been a straight-profile concrete gravity dam with two gate-controlled tunnel spillways, one in each abutment. The proposed reservoir was planned to have a capacity of with an area of . The reservoir was to extend upstream. The power plant was to be capable of generating 850 MW using ten units. The project included provisions for fish hatcheries, with the intention of maintaining salmon runs. Project cost was estimated at $342,076,000. The high dam project was not pursued.

References

External links

Hells Canyon Dam
Northwest Power and Conservation Council
Hells Canyon Complex
Idaho Power {{Snake River Dams Buildings and structures in Adams County, Idaho Dams in Idaho Dams in Oregon Hydroelectric power plants in Idaho Buildings and structures in Wallowa County, Oregon Idaho Power dams Dams completed in 1967 Energy infrastructure completed in 1967 Energy infrastructure completed in 1968 1967 establishments in Oregon Dams on the Snake River Gravity dams 1967 establishments in Idaho United States privately owned dams

High dam proposal

See also

References

External links