Clark Canyon Dam is an earthfill

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 ...

located in

Beaverhead County, Montana Beaverhead County is the largest county by area in the U.S. state of Montana. As of the 2020 census, the population was 9,371. Its county seat is Dillon. The county was founded in 1865. Much of the perimeter of the county is the Continental ...

, about 20 miles (30 km) south of the county seat of

Dillon Dillon may refer to: People *Dillon (surname) * Dillon (given name) * Dillon (singer) (born 1988), Brazilian singer *Viscount Dillon, a title in the Peerage of Ireland Places Canada *Dillon, Saskatchewan United States *Dillon Beach, Californi ...

. The dam impounds the waters of the

Beaverhead River The Beaverhead River is an approximately tributary of the Jefferson River in southwest Montana (east of the Continental Divide). It drains an area of roughly . The river's original headwaters, formed by the confluence of the Red Rock River and H ...

, creating a body of water known as Clark Canyon Reservoir. The structure was constructed in 1961-1964 by the

United States Bureau of Reclamation The Bureau of Reclamation, and formerly the United States Reclamation Service, is a federal agency under the U.S. Department of the Interior, which oversees water resource management, specifically as it applies to the oversight and opera ...

, to hold water for downstream irrigation and for

flood control Flood control methods are used to reduce or prevent the detrimental effects of flood waters."Flood Control", MSN Encarta, 2008 (see below: Further reading). Flood relief methods are used to reduce the effects of flood waters or high water level ...

purposes. Clark Canyon Dam has a crest length of 2,950 feet (899 m), and a maximum height of 147 feet (45 m). The dam contains 1,970,000 cubic yards (1,510,000 m³) of material. The elevation of the dam crest is 5,578 feet (1,700 m). The reservoir has a total capacity of , and when full has a surface area of 5,903 acres (24 km²). Construction of the dam and reservoir required the relocation of

U.S. Route 91 U.S. Route 91 or U.S. Highway 91 (US-91) is a north–south United States highway running from Brigham City, Utah, to Idaho Falls, Idaho, in the U.S. states of Idaho and Utah. Despite the "1" as the last digit in the number, US-91 is no lon ...

(rebuilt as

Interstate 15 Interstate 15 (I-15) is a major Interstate Highway in the western United States, running through Southern California and the Intermountain West. I-15 begins near the Mexican border in San Diego County and stretches north to Alberta, Cana ...

) and a main line of the

Union Pacific Railroad The Union Pacific Railroad , legally Union Pacific Railroad Company and often called simply Union Pacific, is a freight-hauling railroad that operates 8,300 locomotives over routes in 23 U.S. states west of Chicago and New Orleans. Union Paci ...

. The reservoir inundated the former site of the small community of Armstead, Montana, and the site of Camp Fortunate, where the

Lewis and Clark Expedition The Lewis and Clark Expedition, also known as the Corps of Discovery Expedition, was the United States expedition to cross the newly acquired western portion of the country after the Louisiana Purchase. The Corps of Discovery was a select gr ...

camped from August 17 to 22, 1805 and held negotiations with the Shoshone.

Fishing

Fishing is a popular activity on the reservoir created by the dam. The reservoir is regularly stocked with fish.

References

External links

Bureau of Reclamation: Clark Canyon Information
Buildings and structures in Beaverhead County, Montana Dams in Montana United States Bureau of Reclamation dams Dams completed in 1964 Earth-filled dams 1964 establishments in Montana {{BeaverheadCountyMT-geo-stub