Clark Canyon Dam

Clark Canyon Dam
Clark Canyon Reservoir
Clark Canyon Dam is located in Montana
Clark Canyon Dam
Location of Clark Canyon Dam in Montana
CountryUnited States
LocationBeaverhead County, Montana
Coordinates45°00′00″N 112°51′25″W / 45.00000°N 112.85694°W / 45.00000; -112.85694
Construction began1961
Opening date1964
Dam and spillways
Type of damEarthfill
ImpoundsBeaverhead River
Height147.5 ft (45.0 m)
Length2,950 ft (900 m)
Elevation at crest5,578 ft (1,700 m)
Dam volume1,970,000 cu yd (1,510,000 m3)
SpillwaysUncontrolled overflow
Spillway capacity9,520 cu ft/s (270 m3/s)
Reservoir
CreatesClark Canyon Reservoir
Total capacity325,324 acre⋅ft (0.401281 km3)
Surface area5,903 acres (2,389 ha)
Power Station
Hydraulic head113.9 ft (34.7 m)
Installed capacityNone

Clark Canyon Dam is an earthfill dam located in Beaverhead County, Montana, about 20 miles (32 km) south of the county seat of Dillon. The dam impounds the waters of the Beaverhead River, creating a body of water known as Clark Canyon Reservoir. The structure was constructed in 1961-1964 by the United States Bureau of Reclamation, to hold water for downstream irrigation and for flood control purposes.

Clark Canyon Dam has a crest length of 2,950 feet (900 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 325,324 acre-feet (401,281,000 m3), and when full has a surface area of 5,903 acres (23.89 km2).

Construction of the dam and reservoir required the relocation of U.S. Route 91 (rebuilt as Interstate 15) and a main line of the Union Pacific Railroad. 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 camped from August 17 to 22, 1805 and held negotiations with the Shoshone.[1]

  1. ^ Ambrose, Stephen E. (2005). Undaunted Courage. New York: Simon & Schuster. p. 277. ISBN 0-684-82697-6.