Dworshak Dam and Dworshak Reservoir

Originally authorized as Bruces Eddy Dam in the 1962 Flood Control Act, the name was changed to Dworshak Dam in 1963. Construction began in 1966, and the project started operating for flood control in 1972. The three turbine units began generating power in 1973.
Dworshak Dam is the third tallest dam in the U.S. The reservoir extends upstream for roughly 54 miles into the Clearwater National Forest in the Bitterroot Mountains.

Quick Facts

• Stream: North Fork Clearwater River (RM 1.9)
• Location: Ahsahka, Idaho
• Owner: U.S. Army Corps of Engineers, Walla Walla District
• Authorized Purposes: Flood Control, Hydropower (1962 Flood Control Act)
• Other Purposes: Recreation, Fish and Wildlife, Water Quality
• Type of Project: Storage
• Authorized Flood Storage: 2,015,800 acre-feet

Dam

• Dworshak
• Completed: 1972 (flood control); 1973 (hydropower)
• Height: 717 feet
• Length: 3,287 feet
• Features: powerhouse, spillway, fish hatchery
• Forebay Elevation Normal Operating Range: 1,445-1,600 feet msl
• Spillway Capacity (max): 180,000 cfs

Powerhouse

• Generation Capacity: 400 MW, 3 Units
• Hydraulic Capacity: 10,500 cfs

Authorized Purposes

Hydropower

Dworshak Dam has one 220-megawatt turbine unit that is the largest hydroelectric generator in the USACE inventory. The other two units are 90-megawatt, for a total project generating capacity of 400 megawatts–enough to power roughly 300,000 homes.

Flood Risk Management

Dworshak Reservoir has over 2 million acre-feet of storage space for local and regional flood control.

Water Quality

Water quality is monitored and managed consistent with Clean Water Act and state standards for the health of aquatic species.

Recreation

Popular recreation activities at Dworshak Dam and Reservoir include boating, swimming, fishing, hunting, camping, picnicking, geocaching, and hiking. There are roughly 30,000 acres of project lands surrounding the reservoir used for public recreation, wildlife habitat, and timber facilities.

Fish & Wildlife

The height of Dworshak Dam made it infeasible to install fish ladders for upstream fish passage. Instead, the USACE constructed the Dworshak National Fish Hatchery just below the dam in 1969. The U.S. Fish & Wildlife Service operates the hatchery and raises Clearwater River “b-run” steelhead, spring Chinook, coho, and rainbow trout.
Dworshak is operated to benefit salmon and steelhead in the Snake River by releasing cool water from the reservoir during the warm summer months. Water is drawn from various depths in the reservoir to adjust the temperature, which typically ranges from 46°–48°F.
Wildlife mitigation lands are managed to offset habitat losses that occurred when the reservoir filled. About 7,000 acres are managed specifically for habitat for the Rocky Mountain elk.