Mon. Apr 27th, 2026

Grand Coulee Dam

Grand Coulee Dam is a waterworks located on the Columbia River in the United States, specifically in the state of Washington. Like other similar dams, it has several tasks. First of all, it concerns the production of electricity, but of course also the regulation of the watercourse and also water storage tank for irrigation.

The construction of the entire waterworks took place between 1933 and 1942. Two power plants were put into operation. Later, in 1974, a third power plant was put into operation to cover the increased electricity needs.

technical parameters Grand Coulee Dam

Location Grant / Okanogan counties
Country United States
Construction began July 16, 1933
Opening date June 1, 1942
Construction cost
  • Original dam: $163 million
  • Third powerplant: $730 million
Purpose Power, regulation, irrigation
Operator Bureau of Reclamation
Type of dam Concrete gravity
Height 550 ft (168 m)
Length 5,223 feet (1,592 m)
Impounds Columbia River
Width (base) 500 ft (152 m)
Width (crest) 30 ft (9 m)
Spillway capacity 1,000,000 cu ft/s (28,317 m3/s)
Spillway type Service, drum gate
Dam volume 11,975,520 cu yd (9,155,942 m3)
Total capacity reservoir 9,562,000 acre⋅ft (12 km3)
Active capacity reservoir 5,185,400 acre⋅ft (6 km3)
Catchment area 74,100 sq mi (191,918 km2)
Surface area 125 sq mi (324 km2)
Type power station Conventional, pumped-storage
Commission date power station
  • 1941–1950 (Left/Right)
  • 1975–1980 (Third)
  • 1973–1984 (PS)
Turbines
  • 27 × Francis turbines
  • 6 × pump-generators
Hydraulic head 380 ft (116 m)
Capacity factor 36 %
Installed capacity
  • 6,809 MW
  • 7,079 MW (max)
Annual generation 20.24 TWh

Grand Coulee Dam

Grand Coulee Dam Panorama