Diablo Dam, Washington

The Seattle City Light Company operates this and the nearby Ross and Gorge dams, which hold back water on the Skagit River in the north Cascades, and generate electricity for Seattle. The Skagit project started in 1919, and the Diablo Dam, reservoir, and powerhouse was the second of the three to be built, constructed between 1927 and 1936. The Ross Dam, built later, formed a reservoir which extends into Canada.