Grand Coulee Dam

Grand Coulee Dam includes three major hydroelectric power generating plants (named Third, Left, and Right) and the John W. Keys III Pump-Generating Plant. The facilities provide power generation, irrigation, flood risk management, and streamflow regulation for fish migration. Additional incidental benefits include providing flows for navigation and recreation. Grand Coulee Dam is the main feature of the Columbia Basin Project.

Grand Coulee Dam includes three major hydroelectric power generating plants (named Third, Left, and Right) and the John W. Keys III Pump-Generating Plant.

Quick Facts

  • Stream: Columbia River
  • Location: Coulee Dam, Washington
  • Owner: Bureau of Reclamation, Pacific Northwest Region
  • Authorization: National Industrial Recovery Act, 1935 Rivers and Harbors Act
  • Purposes: Irrigation, Hydropower, Flood Risk Management, Recreation, Fish and Wildlife
  • Active Capacity: 5,349,560 acre-feet (total capacity of 9,715,346 acre-feet)
  • Grand Coulee
  • Completed: 1933-1941 (main dam and left powerhouse); 1948 (right powerhouse); 1967-1975 (third power plant and forebay construction)
  • Height: 550 feet
  • Crest Length: 5,223 feet
  • Dam Type: Concrete Gravity
  • Features: powerhouse, spillway, fish hatchery
  • Spillway (type/capacity all at pool elevation 1,290 feet): 11 drum gates / 1,000,000 cfs; 40 outlet works / 265,000 cfs
Powerhouse and pumping plant
  • Generation Capacity: 7,015 MW
  • Left and Right Power Plants: 18 units (6,000 cfs each)
  • Third Power Plant: 6 units (3 / 25,000 cfs each and 3 / 30,000 cfs each)
  • John W. Keys III Pump Generating Plant: 6 pump/generators (2 / 1,605 cfs each and 4 1,700 cfs each); 6 pumps 1,600 cfs each)

Authorized Purposes

Authorized under the National Industrial Recovery Act and later the 1935 Rivers and Harbors Act, the Left Power House was completed in 1941. The Right Power House was completed in 1948. The Third Power Plant was completed in 1975.
The Columbia Basin Project Act of 1943 authorized construction of the Columbia Basin Project, which consists of 330 miles of major distribution canals, lakes and reservoirs, and about 2,000 miles of laterals that currently irrigate approximately 720,000 acres of land.
Power Production
Power production facilities at Grand Coulee Dam are among the largest in the world; the total generating capacity is rated at 6,809 megawatts. Average yearly power production is 21 billion kWh with power distributed to Washington, Oregon, Idaho, Montana, California, Wyoming, Colorado, New Mexico, Nevada, Utah and Arizona. In addition, Canada receives power under the Columbia River Treaty. Grand Coulee Dam is operated as part of a coordinated federal system of hydroelectric facilities, which provides 35% of the entire power supply of the Pacific Northwest.
Flood Risk Management
From January through June, the reservoir level is adjusted for flood risk management. Grand Coulee Dam, the largest Federal storage reservoir on the Columbia River system, works with other storage projects in the system to provide flood risk management for the lower Columbia River including Portland, Oregon and Vancouver, Washington areas.
Economic Value
The economic value of the Columbia Basin Project includes irrigated crops, hydropower production, and the prevention of flood damages and recreations benefits.
Fish Hatcheries
Grand Coulee Dam funds a complex of three fish hatcheries (Leavenworth, Winthrop and Entiat), collectively known as the Leavenworth Complex, to mitigate for the loss of anadromous fish above the dam. Over 2 million spring Chinook and summer steelhead are raised annually.
Grand Coulee Dam creates Franklin D. Roosevelt (FDR) Lake. The lake stretches 151 miles with about 500 miles of shoreline. The lake is co-managed by the National Park Service, Confederated Tribes of the Colville Reservation, Spokane Tribe of Indians, Bureau of Reclamation, and Bureau of Indian Affairs.
Water Operations at Grand Coulee Dam
Grand Coulee Dam operations are closely coordinated to benefit a wide range of needs including hydropower, flood risk management, irrigation, recreation, and operations to benefit resident and anadromous fish.
Maintenance Activities
Annual maintenance on dam outlet works, spill structures, power plants, etc. is necessary for continued operations. Periodically extraordinary maintenance activities are necessary to safely operate the project. Examples include power plant modernization (such as the ongoing efforts in the Third, Left and Right Power Plants), drum gate maintenance overhaul, and maintenance and upgrades to the John W. Keys III Pump Generating Plant.