| Chief Joseph Dam | |
| Coordinates: | 47.9953°N -119.6333°W |
| Location: | Douglas and Okanogan counties, Washington, United States |
| Construction Began: | 1949 |
| Opening: | 1979 |
| Operator: | U.S. Army Corps of Engineers, Seattle District |
| Dam Type: | Concrete-gravity, run-of-the-river |
| Dam Crosses: | Columbia River |
| Dam Length: | 59620NaN0 |
| Dam Width Crest: | 220NaN0 |
| Dam Width Base: | 1640NaN0 |
| Spillway Type: | Service, gate-controlled |
| Spillway Capacity: | 60300NaN0 |
| Res Name: | Rufus Woods Lake |
| Res Capacity Total: | 516000acre.foot |
| Res Catchment: | 754000NaN0 |
| Res Surface: | 13.10NaN0 |
| Plant Operator: | USACE |
| Plant Type: | Hydroelectric |
| Plant Turbines: | 27 x Francis turbines |
| Plant Capacity: | 2,620 MW |
| Plant Capacity Factor: | 42.6% |
| Plant Annual Gen: | 9,780 GWh (2009)[1] |
| Website: | U.S. Army Corps of Engineers - Chief Joseph Dam |
| Dam Height: | 2360NaN0[2] |
The Chief Joseph Dam is a concrete gravity dam on the Columbia River, 2.41NaN1 upriver from Bridgeport, Washington. The dam is 8770NaN0 upriver from the mouth of the Columbia at Astoria, Oregon. It is operated by the USACE Chief Joseph Dam Project Office and the electricity is marketed by the Bonneville Power Administration.
The dam was authorized as Foster Creek Dam and Powerhouse for power generation and irrigation by the River and Harbor Act of 1946. The River and Harbor Act of 1948 renamed the project Chief Joseph Dam in honor of the Nez Perce chief who spent his last years in exile on the Colville Indian Reservation. Because of its lack of fish ladders, Chief Joseph Dam completely blocks salmon migration to the upper Columbia River system.
Construction began in 1950, with the main dam and intake structure completed in 1955. Installation of the initial generating units was started in 1958 and completed in 1961. Ten additional turbines were installed between 1973 and 1979, and the dam and lake were raised 30NaN0, boosting the capacity to, making Chief Joseph Dam the second largest hydroelectric power producer in the United States.[3]
Chief Joseph Dam is a run-of-the-river dam which means the lake behind the dam is not able to store large amounts of water. Water flowing to Chief Joseph Dam from Grand Coulee Dam must be passed on to Wells Dam at approximately the same rate. With 27 main generators in the powerhouse, it has the hydraulic capacity of 6030m3/s.
In the event more water flows to Chief Joseph Dam than could be used for power generation, the spillway gates would be opened to pass the excess water. With an average annual flow rate of 30580NaN0, the Columbia River seldom exceeds the powerplant's capability to pass water, and spilling of water is infrequent at Chief Joseph Dam.
The reservoir behind the dam is named Rufus Woods Lake, and runs 820NaN0 up the river channel. Bridgeport State Park, on the lake, is adjacent to the dam.