US Army Corps of Engineers
Northwestern Division

CRSO EIS Featured Project - Dworshak Dam

Dworshak Dam

Columbia River System Operations EIS
Published Nov. 22, 2019
By 2018, the Corps’ operation of Dworshak Dam in Idaho had prevented more than $4.4 million in potential local flood damages. From October 2014 through September 2018, the dam prevented approximately $216 million in potential flood damages on the Columbia River.

By 2018, the Corps’ operation of Dworshak Dam in Idaho had prevented more than $4.4 million in potential local flood damages. From October 2014 through September 2018, the dam prevented approximately $216 million in potential flood damages on the Columbia River.

Featured Project

The Columbia River System is large and complex. This educational feature introduces you to individual projects that play a role in supporting the region’s tribes, communities, industries and fish and wildlife species.

Dworshak Dam

The U.S. Army Corps of Engineers operates and maintains Dworshak Dam on the North Fork Clearwater River in Idaho. At 717 feet, Dworshak is the third tallest dam in the United States. It began operating in 1972 to provide 2 million acre-feet of water storage space to reduce local and regional flood risks. It began generating hydropower in 1973. The project’s 220-megawatt turbine unit is the largest hydroelectric generator in the Corps’ inventory. Combined with two other units that each produce 90,000 kilowatts of power, Dworshak can generate enough to power roughly 300,000 homes.

The height of Dworshak Dam made it impractical to install fish ladders for upstream fish passage. Instead, the Corps constructed the Dworshak National Fish Hatchery below the dam in 1969 to mitigate for lost fisheries resulting from dam construction and operation. The U.S. Fish and Wildlife Service and the Nez Perce Tribe operate and maintain the hatchery that raises Clearwater River steelhead and spring chinook and coho salmon.

Releasing cool water from various depths in the reservoir during the warm summer months helps the continuance of existing fish runs. Operators adjust downstream water temperatures through water releases from a multi-level intake structure on the dam’s upstream face that is used for power generation. Wildlife mitigation lands are managed to offset habitat losses that occurred when the reservoir filled. About 9,000 acres are managed specifically for Rocky Mountain elk habitat.

Approximately 30,000 acres of the Corps’ land surrounding the reservoir provide recreation, wildlife habitat and timber facilities. Popular recreation activities include boating, swimming, fishing, hunting, camping, picnicking, geocaching and hiking.

The Corps operates the Dworshak project in close coordination with the 13 other federal projects that comprise the Columbia River System and serve a wide range of purposes.

To learn more about Dworshak Dam, visit www.nww.usace.army.mil/Locations/District-Locks-and-Dams/Dworshak-Dam-and-Reservoir