Lower Monumental Dam

Lower Monumental Lock and Dam is a hydroelectric, concrete, run-of-the-river dam in the northwest United States. Located on the lower Snake River in southeast Washington, it bridges Franklin and Walla Walla counties; it is south of Kahlotus and north of Walla Walla.
[Image:LwrMnDam2.jpg|thumb|left|Lower Monumental Dam with the lock in the center of the river (far side in photo), the power generation on the northwest side of the river, and spillway in the middle of the dam, between the powerhouse and the lock.]
Construction began in June 1961, and the main structure and three generators were completed in 1969, with an additional three generators finished in 1981. Generating capacity is 810 megawatts, with an overload capacity of 932 MW. The spillway has eight gates and is in length.
Built and operated by the U.S. Army Corps of Engineers, Lower Monumental Dam is part of the Columbia River Basin system of dams.
Behind the dam, Lake Herbert G. West is the reservoir; it extends east to the base of Little Goose Dam. Lake Sacajawea, formed from Ice Harbor Dam, runs southwest, downstream from the base of the dam.
;Navigation lock