Ross Dam

Ross Dam
Ross Dam during the Skagit River floods of 2003.
Location	Ross Lake National Recreation Area, Whatcom County, Washington, USA
Coordinates	48°43′54″N 121°04′02″W / 48.73167°N 121.06722°W / 48.73167; -121.06722Coordinates: 48°43′54″N 121°04′02″W / 48.73167°N 121.06722°W / 48.73167; -121.06722
Construction began	1937
Opening date	1949
Dam and spillways
Impounds	Skagit River
Height	540 feet (160 m)
Length	1,300 feet (400 m)
Reservoir
Creates	Ross Lake
Total capacity	1,435,000 acre feet (1.770 km3)
Surface area	11,700 acres (4,700 ha)
Power station
Turbines	4
Installed capacity	460 MW
Annual generation	619,120,000 KWh
Website http://www.seattle.gov/light/FuelMix/

Ross Dam is a 540-foot (160 m)-high, 1,300-foot (400 m)-long concrete thin-arch dam across the Skagit River, forming Ross Lake. The dam is in Washington State, while Ross Lake extends 23 miles (37 km) north to British Columbia, Canada. Both dam and reservoir are located in Ross Lake National Recreation Area, is bordered on both sides by Stephen Mather Wilderness and combined with Lake Chelan National Recreation Area they make up North Cascades National Park Complex.

Built as part of the Skagit River Hydroelectric Project by Seattle City Light, the dam is part of a series of three dams through the Skagit Gorge that were built primarily to generate hydroelectricity from the massive elevation drop of over 1,000 feet (300 m) from the Canada-U.S. border to Newhalem. The other two dams are Diablo Dam, directly below Ross Dam, and Gorge Dam, further downstream. Ross Dam can generate up to 460 MW of electricity. Hydro-electric dams provide approximately 92 percent of the electricity used in Seattle.

Prior to construction of the dam the Skagit Gorge upstream of the dam was a wild, free flowing, completely undeveloped area. The canyon held an intact virgin ancient forest of Douglas Fir, Western Hemlock and Western Redcedar, estimated to be millable into up to 340 million usable board feet of timber. With the creation of the Skagit River Hydroelectric Project in the 1910s, the first two dams, Gorge Dam and Diablo Dam, were constructed downstream of the Ross Dam site. In 1937, construction began on the dam, originally slated to be called Ruby Dam, on the first two of four planned construction phases. The name originates from the wife of Dam proponent James Ross, it is also the name of Ruby Creek, a Skagit River tributary that flows southwest to meet the Skagit just upstream of the dam site. By 1940, phases 1 and 2 of the dam were complete, and the dam stood 305 feet (93 m) above the river. While the reservoir filled, the Decco-Walton Logging Company was formed in 1945 with the awarding of a contract from Seattle City Light. Decco-Walton logged the Skagit Gorge as Ross Lake slowly rose, and floated logs up the river to British Columbia, where it was hauled to the Fraser River. By the time Ross Lake filled, only 30 million board feet remained in the basin, less than 10% of the original timber.