Wanapum Dam is a run-of-the-river 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 1,185 megawatts and annually generates over 4 million megawatt-hours.