Anderson Ranch Dam is an earth rockfill type

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, aqua ...

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 South Fork of the

Boise River The Boise River is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data. , accessed May 3, 2011 tributary of the Snake River in the Northwestern United States. It drains a rugged portion of the Sawtooth Range in so ...

southwestern The points of the compass are a set of horizontal, radially arrayed compass directions (or azimuths) used in navigation and cartography. A ''compass rose'' is primarily composed of four cardinal directions—north, east, south, and west—each ...

Idaho Idaho ( ) is a landlocked U.S. state, state in the Pacific Northwest and Mountain states, Mountain West subregions of the Western United States. It borders Montana and Wyoming to the east, Nevada and Utah to the south, and Washington (state), ...

. In Elmore County northeast of Mountain Home, it is several miles north of U.S. Route 20 and operated by the U.S. Bureau of Reclamation. When completed in 1950, Anderson Ranch was the tallest dam of its type in the world. Its primary purpose is to provide

irrigation Irrigation (also referred to as watering of plants) is the practice of applying controlled amounts of water to land to help grow crops, landscape plants, and lawns. Irrigation has been a key aspect of agriculture for over 5,000 years and has bee ...

water for agriculture, with a secondary purpose of

hydroelectric Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energ ...

power. Its generating capacity was increased from 27 to 40 MW in 1986.Anderson Ranch Dam
, NPDP Dam Directory Its reservoir has a spillway

elevation The elevation of a geographic location (geography), ''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 equipotenti ...

of 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 ...

. The construction of the dam began in 1941 and experienced numerous challenges with materials, fuel, and labor shortages during

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

. Work was halted for over nine months beginning in late December 1942. The

Reclamation Act of 1902 The Reclamation Act (also known as the Lowlands Reclamation Act or National Reclamation Act) of 1902 () is a United States federal law that funded irrigation projects for the arid lands of 17 states in the American West. The act at first cove ...

had racial exclusions on labor which were strictly adhered to until Congress changed the law in 1943. This allowed Japanese American internees to work on Reclamation projects; Anderson Ranch utilized internees from the

Minidoka War Relocation Center Minidoka National Historic Site is a National Historic Site in the western United States. It commemorates the more than 13,000 Japanese Americans who were imprisoned at the Minidoka War Relocation Center during the Second World War.

, northeast of Twin Falls.National Park Service
- history - Anderson Ranch Dam & Powerplant, Idaho - accessed 2012-02-09 The South Fork of the Boise River originates in the

Smoky Mountains The Great Smoky Mountains (, ''Equa Dutsusdu Dodalv'') are a mountain range rising along the Tennessee–North Carolina border in the southeastern United States. They are a subrange of the Appalachian Mountains The Appalachian Mountains, ...

north of Fairfield. Its watershed includes portions of the Smoky Mountains,

Soldier Mountains The Soldier Mountains are a mountain range in the U.S. state of Idaho, spanning northern Camas and eastern Elmore counties. The highest point in the range is Smoky Dome at , and the range is bounded on the west and north by the South Fork B ...

Boise National Forest Boise National Forest is a United States National Forest, National Forest covering of the U.S. state of Idaho. Created on July 1, 1908, from part of Sawtooth National Forest, it is managed by the United States Forest Service, U.S. Forest Se ...

, and

Sawtooth National Forest Sawtooth National Forest is a United States National Forest, National Forest that covers 2,110,408 acres (854,052 ha) in the U.S. states of Idaho (~96 percent) and Utah (~4 percent). Managed by the U.S. Forest Service in the United States Depart ...

. Below the dam, the South Fork flows northwestward into the reservoir behind the concrete

Arrowrock Dam Arrowrock Dam is a concrete Arch dam, arch dam in the Western United States, western United States, on the Boise River in Southwestern Idaho, southwestern Idaho, east of Boise, Idaho, Boise. Opened in 1915, it is located on the border of Boise ...

, completed in 1915. The Bureau of Reclamation and Idaho Water Resource Board are working on raising the dam by , resulting in approximately of new storage space. The design is scheduled for completion in the summer of 2024.
U.S. Bureau of Reclamation, Anderson Ranch Dam Raise Milestones - accessed 2022-07-18

References

External links

USBR.gov
- Bureau of Reclamation - Anderson Ranch Dam

- Anderson Ranch Dam

- major storage reservoirs in the Boise & Payette River basins - current levels & flows {{DEFAULTSORT:Anderson Dams in Idaho Reservoirs in Idaho Hydroelectric power plants in Idaho Buildings and structures in Elmore County, Idaho United States Bureau of Reclamation dams Dams completed in 1950 Energy infrastructure completed in 1950 Boise Project