Lower Granite Lock and Dam is a hydroelectric, concrete, gravity dam on the Snake River, and bridges Whitman County and Garfield County, in the 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.



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.

Stats:

Location: 46.6604369 -117.4279602
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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 135,000-megawatt units *