Grand Coulee Columbia Rivers pathway and onto the southern plateau creating an ice dam. This dam backed up the waters of the Columbia into Glacial Lake Columbia and later during the Missoula Floods forced those waters into eastern Washington, creating the Scablands. The river at Grand Coulee found no existing valley and thus forged its own pathway across the divide, creating the Upper Coulee. The plateau is not level, but is marked with wrinkles and upfolds of the basalt. The diverted waters of the Columbia, encountered the monoclinal flexure, a steep warping up of toward the northwest. Lake Columbia topped the ridge
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