page_title: Lower Monumental Dam
hierarchical_section_title: Lower Monumental Dam
context_page_description: Lower Monumental Lock and Dam is a hydroelectric, concrete, run-of-the-river dam in the northwest United States. Located on the Snake River, it bridges Franklin and Walla Walla counties in southeast Washington. It is six miles south of Kahlotus and 43 miles north of Walla Walla.
  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 572 feet in length.
  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 28 miles east to the base of Little Goose Dam. Lake Sacajawea, formed from Ice Harbor Dam, runs 22 miles southwest, downstream from the base of the dam.
  Navigation lock
  Single-lift
  Width: 86 ft
  Length: 666 ft
context_section_description: Lower Monumental Lock and Dam is a hydroelectric, concrete, run-of-the-river dam in the northwest United States. Located on the Snake River, it bridges Franklin and Walla Walla counties in southeast  Washington. It is six miles (10 km) south of Kahlotus and 43 miles (70 km) north of Walla Walla.
  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 572 feet (174 m) in length.
  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 28 miles (45 km) east to the base of Little Goose Dam. Lake Sacajawea, formed from Ice Harbor Dam, runs 22 miles (35 km)  southwest, downstream from the base of the dam.
  Navigation lock
  Single-lift
  Width: 86 ft (26 m)
  Length: 666 ft (203 m)
caption: 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.
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