Diablo Dam

Diablo Dam
Location	Washington, United States
Opening date	1930
Dam and spillways
Type of dam	Concrete arch-gravity[1]
Impounds	Skagit River
Height	389 ft (119 m)[1]
Length	1,180 ft (360 m)[1]
Reservoir
Total capacity	88,500 acre⋅ft (109,200,000 m3)[1]
Catchment area	1,103 sq mi (2,860 km2)[1]
Surface area	990 acres (400 ha)[1]
Commission date	1936
Turbines	2x 64.5 MW[2]
Installed capacity	129 MW[2]
Capacity factor	61%
Annual generation	689,400,000 KWh[3]

Diablo Dam is one of three dams along the upper Skagit River in Whatcom County, Washington and part of the Skagit River Hydroelectric Project that supplies Seattle with some of its power needs. The dam was built in Diablo Canyon, a gorge of solid granite with vertical walls rising 160 feet (49 m) from the river bed, yet were less than 100 feet (30 m) apart. Construction began in 1927, and was completed in 1930. The dam began generating electricity in 1936.^[4]

The result was a power-generating dam that holds a reservoir known as Diablo Lake. At the time it was completed, Diablo Dam, at 389 feet (119 m), was the tallest dam in the world.^[5] Water from the dam operates two main generators, each with a capacity of 64.5 MW.^[2]48°42′51″N 121°07′52″W / 48.7143°N 121.1312°W / 48.7143; -121.1312 The dam and its original associated power generation infrastructure were listed on the National Register of Historic Places in 1989.^[6]