The Columbia River Collection role. The United States Department of the Interior hired him for one month to write songs about the Columbia River and the construction of the federal dams for the documentary's soundtrack. Guthrie toured the Columbia River and the Pacific Northwest. Guthrie said he "couldn't believe it, it's a paradise", which appeared to inspire him creatively. In one month Guthrie wrote 26 songs, including three of his most famous: "Roll On, Columbia, Roll On", "Pastures of Plenty", and "Grand Coulee Dam". The surviving songs were released as "Columbia River Songs". The film "Columbia" was not completed until 1949. Track Listing of
Grand Coulee Dam of electricity. Each generator is supplied with water by an individual penstock. The largest of these feed the Third Powerplant and are in diameter and can supply up to . The dam's power facilities originally had an installed capacity of 1,974 MW but expansions and upgrades have increased generation to 6,809 MW installed, 7,079 MW maximum. Grand Coulee Dam generates 21 TWh of electricity annually. This means the dam generates about 2,397 MW of power on average, which results in a total plant factor efficiency of 35%. In 2014, 20.24 TWh of electricity was generated. Grand Coulee Dam's spillway is