Roll On, Columbia, Roll On near Cascades Rapids, in The Dalles, and on Memaloose Isle. The final three verses describe the construction of two Columbia River dams: Bonneville Dam and Grand Coulee Dam. Bonneville Dam, the first dam built on the Columbia, had locks built into it so ships could navigate past it, alleviating worries that a dam would prevent the shipment of goods and passengers along the length of the river. Guthrie's lyrics describe Grand Coulee Dam as "the mightiest thing ever built by a man"; when it was built it was the largest concrete dam in the world, and as of 2012 it
Grand Coulee Dam Wenatchee. Together, they became known as the "Dam College". Woods began promoting the Grand Coulee Dam in his newspaper, often with articles written by O'Sullivan. The dam idea gained popularity with the public in 1918. Backers of reclamation in Central Washington split into two camps. The "pumpers" favored a dam with pumps to elevate water from the river into the Grand Coulee from which canals and pipes could irrigate farmland. The "ditchers" favored diverting water from northeast Washington's Pend Oreille River via a gravity canal to irrigate farmland in Central and Eastern Washington. Many locals such as Woods, O'Sullivan and