Skagit River Hydroelectric Project

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Skagit River and Newhalem Creek Hydroelectric Projects
Diablo Dam Skagit 2003 Flood.jpg
Skagit River Hydroelectric Project is located in Washington (state)
Skagit River Hydroelectric Project
LocationWhatcom County, Washington
Nearest cityNewhalem, Washington
Area42 acres (17.0 ha)
ArchitectSeattle Engineering Dept.; Jorgenson, Lars
Architectural styleClassical Revival, Bungalow/American craftsman, Other, Industrial
MPSHydroelectric Power Plants in Washington State, 1890--1938 MPS
NRHP reference #96000416[1] (original)
11000016 (increase)
Significant dates
Added to NRHPApril 26, 1996
Boundary increaseFebruary 11, 2011
Gorge Dam on the Skagit River
Ross Dam on the Skagit River

The Skagit River Hydroelectric Project is a series of dams with hydroelectric power-generating stations on the Skagit River in northern Washington State. The project is owned and operated by Seattle City Light to provide electric power for the City of Seattle and surrounding communities.

In 2012, hydro-electric dams provided approximately 89.8 percent of the electricity used in Seattle.[2] The Skagit Hydroelectric Project alone accounts for about 20 percent of Seattle City Light's electricity.

The three major dams in the Skagit River Project are (from lower to upper) Gorge Dam, Diablo Dam, and Ross Dam. The dams are located in Whatcom County above the town of Newhalem, which lies just west of North Cascades National Park. Ross Lake, formed by Ross Dam extends into British Columbia, which is 20 miles upriver from the dam. Ross Lake National Recreation Area surrounds the lake.

Construction of Gorge Dam 48°41′52″N 121°12′30″W / 48.69778°N 121.20833°W / 48.69778; -121.20833 began in 1921 and the first power was delivered to Seattle in 1924. The cost of the dam was $13 million ($153,339,181 in 2006 dollars).[3] In 1961 a new Gorge High Dam was completed (300 feet, 91 meters) to replace the original Gorge Dam. This dam was featured in Alan Pakula's 1974 thriller The Parallax View, starring Warren Beatty.

Construction of Diablo Dam 48°42′51″N 121°07′52″W / 48.71417°N 121.13111°W / 48.71417; -121.13111 was begun in 1927, five miles upstream from Gorge Dam. Diablo Dam was completed in 1930, and at that time was the tallest dam in the world at 389 feet (119 meters) until Owyhee Dam was built. However, the dam produced no electricity for Seattle until 1936.[further explanation needed]

Construction of Ruby Dam 48°43′54″N 121°04′02″W / 48.73167°N 121.06722°W / 48.73167; -121.06722 at the Rip Raps below Ruby Creek began in 1937. This dam was renamed Ross Dam after the death of James Delmage Ross (1872–1939), the superintendent of the Skagit River Project. Construction of Ross Dam was to take place in three stages and the first stage was completed in 1940. The second and third stages were completed in 1953 when the dam was built to its final height of 540 feet (165 meters).

All three dams were listed in the National Register of Historic Places.

Hydroelectric power capacity[edit]

Dam Power (MW)[4]
Gorge 199.2
Diablo 159.3
Ross 352.6
Total 711.1
Gorge Powerhouse, Newhalem, WA


  1. ^ National Park Service (2010-07-09). "National Register Information System". National Register of Historic Places. National Park Service.
  2. ^ "Fuel Mix - How Seattle City Light electricity is generated". Seattle City Light. Retrieved 11 March 2014.
  3. ^ Dollar worth calculator at the Federal Reserve Bank of Minneapolis Archived 2008-01-15 at the Wayback Machine
  4. ^ Seattle City Light


External links[edit]