Wanapum Dam
| Wanapum Dam | |
|---|---|
Dam viewed from downstream on the west bank
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| Official name | Wanapum Dam |
| Location | Grant / Kittitas counties, Washington |
| Coordinates | 46°52′31″N 119°58′16″W / 46.875213°N 119.971004°WCoordinates: 46°52′31″N 119°58′16″W / 46.875213°N 119.971004°W |
| Construction began | 1959 |
| Opening date | 1963 |
| Construction cost | US$93,277,690 |
| Dam and spillways | |
| Impounds | Columbia River |
| Height | 185 feet (56 m) |
| Length | 8,320 feet (2,540 m) |
| Reservoir | |
| Creates | Lake Wanapum |
| Total capacity | 796,000 acre feet (982,000,000 m3) |
| Power station | |
| Commission date | 1963 |
| Turbines | 10 x 104 MW Kaplan-type |
| Installed capacity | 1,040 megawatts (1,390,000 hp) |
Wanapum Dam is a hydroelectric project located on the Columbia River downstream (south) from Vantage, Washington where Interstate 90 crosses the Columbia from Grant County into Kittitas County. It is owned by the Grant County Public Utility District. Its reservoir is named Lake Wanapum.
The dam, and its lake, are named after the Wanapum Indians. The dam has a rated capacity of 1,040 megawatts and annually generates over 4 million megawatt-hours.
The Wanapum dam was originally licensed in 1955 for a period of 50 years. Construction was initiated in 1959 with initial beneficial operation in 1963. The initial license expired in 2005, after which the Grant County PUD operated the dam on yearly license extensions while negotiations for license extension proceeded. The Federal Energy Regulatory Commission approved a license extension of 44 years for both the Wanapum dam and the downstream Priest Rapids dam on April 17, 2008. The license extension was conditioned upon programs to achieve the following goals:
On February 27, 2014, a 2-inch (5 cm) wide crack was discovered by inspection divers on one of the 65 feet (20 m) tall concrete monoliths that make up the spillway of the dam. A spokesman for the Grant County PUD indicated that the level of the water was to be lowered by 26 feet (8 m) over a period of days to "reduce the pressure on the spillway while inspectors investigate".
According to Washington State Parks, Wanapum State Park will be closed until further notice Effective Monday, April 28, 2014, due to the fracture in the structure of Wanapum Dam. "Grant County Public Utility District has closed all beaches and water access in the area above the dam, which includes Wanapum State Park, to protect sensitive cultural resources and help to ensure public safety. Because water access is integral to the park and a primary focus for visitors, all access to Wanapum State Park will be closed until further notice.
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