Anderson Ranch Dam is an earth rockfill type dam

Dam

A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...

 on the South Fork of the Boise River

Boise River

The Boise River is a tributary of the Snake River in the northwestern United States. It drains a rugged portion of the Sawtooth Range in southwestern Idaho northeast of Boise, as well as part of the western Snake River Plain...

, in Elmore County

Elmore County, Idaho

Elmore County is a county located in the U.S. state of Idaho. As of the 2010 Census the county had a population of 27,038, down 7.2% from 29,130 in 2000. The largest city and county seat is Mountain Home....

, Idaho

Idaho

Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....

, U.S.A.  Its reservoir is plainly called "Anderson Ranch Reservoir" and has a spillway elevation of 4196 feet (1279 m) above sea level. The dam is northeast of Mountain Home

Mountain Home, Idaho

Mountain Home is the largest city and county seat of Elmore County, Idaho. The population was 14,206 at the 2010 census. Mountain Home is the principal city of the Mountain Home, ID Micropolitan Statistical Area, which includes Elmore County....

 and several miles north of US 20

U.S. Route 20

U.S. Route 20 is an east–west United States highway. As the "0" in its route number implies, US 20 is a coast-to-coast route. Spanning , it is the longest road in the United States, and the route sparsely parallels Interstate 90...

.

When completed in 1950, Anderson Ranch was the tallest dam of its type in the world. http://www.usbr.gov/power/data/sites/anderson/anderson.html Its primary purpose is to provide irrigation water for agriculture. Its secondary purpose is for the production of hydroelectric

Hydroelectricity

Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy...

 power.

The South Fork of the Boise River originates in the Smoky Mountains north of Fairfield

Fairfield, Idaho

Fairfield is the county seat of and the only city in Camas County, Idaho, United States. The population was 395 at the 2000 census, nearly half of the rural county's population.-Geography:...

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

Arrowrock Dam

Arrowrock Dam is a concrete arch type dam on the Boise River, in Idaho, U.S.A. It opened in 1915 and is located on the border between Boise County and Elmore County, upstream of the Lucky Peak Dam and reservoir...

.

External links

• USBR.gov - Bureau of Reclamation - Anderson Ranch Dam
• Idaho Dept. of Water Resources - Anderson Ranch Dam