Caption:
Lower Monumental Lock and Dam is a hydroelectric, concrete gravity dam on the Snake River in Washington State. It is part of the Columbia River Basin system of dams, built and is operated by the U.S. Army Corps of Engineers. Its electricity is distributed by the Bonneville Power Administration. The main structure and three generators were completed in 1969, with an additional three generators added in 1981. Generating capacity is 810 megawatts, with an overload capacity of 932 MW. The spillway has eight gates and is 572 feet (176 m) long.