Rahul Sharma (Editor)

Lower Monumental Dam

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Opening date  1969
Height  30 m
Length  1,155 m
Phone  +1 509-282-3218
Impounds  Snake River
Opened  1969
Create  Lake Herbert G. West
Construction began  June 1961
Lower Monumental Dam
Location  Franklin / Walla Walla counties, Washington, USA
Operator(s)  U.S. Army Corps of Engineers
Type of dam  Concrete gravity, run-of-the-river
Spillway type  Service, gate-controlled
Address  5220 Devils Canyon Rd, Prescott, WA 99335, USA
Similar  Little Goose Dam, Ice Harbor Dam, Lower Granite Dam, Snake River, McNary Dam

Preparing to replace lock gate at lower monumental dam

Lower Monumental Lock and Dam is a hydroelectric, concrete, run-of-the-river dam on the Snake River, and bridges Franklin County and Walla Walla County, in the state of Washington. The dam is located six miles (10 km) south of the town of Kahlotus, and 43 miles (69 km) north of the town of Walla Walla.


Construction began in June 1961. 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 (176 m) long.

Lower Monumental Dam is part of the Columbia River Basin system of dams.

Lake Herbert G. West, which extends 28 miles (45 km) east to the base of Little Goose Dam, is formed behind the dam. Lake Sacajawea, formed from Ice Harbor Dam, runs 35 miles (56 km) southwest, downstream from the base of the dam.

Navigation lock
  • Single-lift
  • 86 feet (26 m) wide
  • 666 feet (203 m) long
  • Lower monumental dam


    Lower Monumental Dam Wikipedia

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    Little Goose Dam
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