Lower Monumental Lock and Dam is a hydroelectric, concrete, run-of-the-river

Run-of-the-river hydroelectricity

Run-of-the-river hydroelectricity is a type of hydroelectric generation whereby a considerably smaller water storage called pondage or none is used to supply a power station. Run-of-the-river power plants are classified as with or without pondage...

 dam

Dam

A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...

 on the Snake River

Snake River

The Snake is a major river of the greater Pacific Northwest in the United States. At long, it is the largest tributary of the Columbia River, the largest North American river that empties into the Pacific Ocean...

, 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

Kahlotus, Washington

Kahlotus is a city in Franklin County, Washington, United States. The population was 193 at the 2010 census.-History:The first organized settlement of Kahlotus was by German immigrants, imported by the railroads, in around 1880. Among these settlers were several locally recognized pioneer...

, and 43 miles (69 km) north of the town of Walla Walla

Walla Walla, Washington

Walla Walla is the largest city in and the county seat of Walla Walla County, Washington, United States. The population was 31,731 at the 2010 census...

.

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

Columbia River

The Columbia River is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia, Canada, flows northwest and then south into the U.S. state of Washington, then turns west to form most of the border between Washington and the state...

 system of dams.

Lake Herbert G. West

Lake Herbert G. West

Lake Herbert G. West is a reservoir formed by the Lower Monumental Dam. It extends up the Snake River for 28 miles to the tailwater of Little Goose Dam...

, which extends 28 miles (45 km) east to the base of Little Goose Dam

Little Goose Lock and Dam

Little Goose Lock and Dam is a hydroelectric, concrete, run-of-the-river dam in Columbia and Whitman counties in the state of Washington, on the Snake River. The dam is located northeast of the town of Starbuck, and north of Dayton....

, is formed behind the dam. Lake Sacajawea

Lake Sacajawea (Washington)

Lake Sacajawea is formed by the Ice Harbor Dam on the Snake River. It stretches from there upstream to the Lower Monumental Dam. It is named for Sacajawea, a Shoshone woman who accompanied Meriwether Lewis and William Clark during their exploration of the American West....

, formed from Ice Harbor Dam

Ice Harbor Lock and Dam

Ice Harbor Lock and Dam is a hydroelectric, concrete gravity run-of-the-river dam on the Snake River in Walla Walla and Franklin counties in the U.S. state of Washington. The dam is located 8 miles northeast of the town of Burbank and 12 miles east of Pasco, river mile 9.2...

, 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

External links

• Lower Monumental Lock & Dam @ US Army Corps of Engineers