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:
modernize the power generation capability of the dam
monitor water quality
improve wildlife habitat
protect nearly 700 Wanapum Tribe archaeological sites in the vicinity
enhance recreation with new campsites, picnic areas and trails
On 27 February 2014, a 2 inches (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".
Basalt bluff over the Columbia River near Wanapum Dam
^"License OK'd for Columbia Dams". Tri-City Herald (Kennewick, WA: McClatchy Company). 2008-04-20. p. A6.Cite uses deprecated parameters (help)
^"Crack found in Washington dam on Columbia River". USA Today (Gannet Company). 2014-03-01. "A 65-foot-long crack in a Columbia River dam in central Washington has prompted officials to begin lowering the water level by 20 feet so inspectors can get a better idea of how serious the damage is."