Lower Granite Lock and Dam

From Wikipedia, the free encyclopedia

Lower Granite Dam and the Snake River from the northwest, looking southeast, upstream.
Lower Granite Dam and the Snake River from the northwest, looking southeast, upstream.

Lower Granite Lock and Dam is a hydroelectric concrete gravity dam on the Snake River, and bridges Whitman County and Garfield County, in the U.S. state of Washington. The dam is located 22 miles (35 km) south of the town of Colfax, and 35 miles (56 km) north of Pomeroy.

Construction began in July 1965. The main structure and three generators were completed in 1972, with an additional three generators finished in 1979. Generating capacity is 810 megawatts, with an overload capacity of 932 MW. The spillway has eight gates and is 512 feet (156 m) long.

Lower Granite Dam is part of the Columbia River Basin system of dams. It was built and is operated by the United States Army Corps of Engineers. Power generated is distributed by the Bonneville Power Administration.

Lower Granite Dam with the lock in the center, the power generation on the south side of the river, and spillway in the middle of the dam, between the powerhouse and the lock.
Lower Granite Dam with the lock in the center, the power generation on the south side of the river, and spillway in the middle of the dam, between the powerhouse and the lock.

Lower Granite Lake, which extends 39-miles east to Lewiston, Idaho, is formed behind the dam. Lake Bryan, formed from Little Goose Dam, runs 37 miles (60 km) downstream from the base of the dam.

Lower Granite Dam is the most upstream dam in the Snake River system that has fish ladders (2) to allow adult salmon and steelhead to migrate upstream. The Columbia River treaty tribes along with some environmental groups have recommended that this dam along with the other three lower Snake River dams be decommissioned and/or removed because of their impact on endangered salmon and steelhead populations.[citation needed] The Army Corps of Engineers has installed new devices such as removable spillway weirs in an attempt to make the dam less harmfull to juvenile salmon.

There is also a juvenile bypass/collection facility that collects juvenile migrating salmon and steelhead so they can be transported downstream by barge.

Stats:

  • Location: 46.6604369 -117.4279602
    ( 46°39′37″N, 117°25′40″W)
  • Altitude: 741 feet (226 m) above sea level
  • Height: 100 feet (30 m)
  • Length: 3,200 feet (975 m)
  • Navigation lock:
    • Single-lift
    • 86 feet (26 m) wide
    • 674 feet (205 m) long
  • Powerhouse
    • Six 135-megawatt units [1]
Columbia River Basin
Columbia River Basin

[edit] External links


v • d • e
Snake River Dams