Moses Coulee the southern portion of the plateau. These streams had combined into a canyon that drained to the Columbia near the current mouth of Moses Coulee. These side drainages are still visible today along the coulee walls as truncated streambeds, interspersed with gable-like highlands. The Okanogan lobe of the Cordilleran Glacier moved down the Okanogan River valley, covering 500 mi² of the Waterville Plateau and blocked the ancient route of the Columbia River, backing up water to create Glacial Lake Columbia and Lake Spokane. Initially water discharged from Lake Columbia by running up through the head of Grand Coulee and down
Grand Coulee Dam (song) the recommendation of Alan Lomax, the BPA hired Guthrie to write a set of propaganda songs about the federal projects to gain support for federal regulation of hydroelectricity. Although the intended documentary film was not completed until 1949, Guthrie's songs were recorded in Portland, Oregon in May 1941. The tune for "Grand Coulee Dam" is based on that of the traditional song, "The Wabash Cannonball". Guthrie's recording was reissued on the Folkways album "Bound For Glory" in 1956, and subsequently on numerous compilations of Guthrie's songs. The song was later recorded by British skiffle musician Lonnie Donegan, whose version entered