Moses Coulee through Foster Coulee to rejoin the Columbia River. As the glacier moved further south, Foster Coulee was cut off and the Columbia River then discharged through Moses Coulee, which runs southward slightly to the east of the ancient and current course of the Columbia. As the Okanogan lobe grew, it blocked Moses Coulee as well; the Columbia found the next lowest route through the region which was eroded to become the modern Grand Coulee. Flowing across the current Grand Coulee and Dry Falls regions, the ice age Columbia then entered the Quincy Basin and joined Crab Creek, following Crab Creek’s
Grand Coulee Dam The dam's powerhouse began production around the time World War II began, and its electricity was vital to the war effort. The dam powered aluminum smelters in Longview and Vancouver, Washington, Boeing factories in Seattle and Vancouver, and Portland's shipyards. In 1943, its electricity was also used for plutonium production in Richland, Washington, at the Hanford Site, which was part of the top-secret Manhattan Project. The demand for power at that project was so great that in 1943, two generators originally intended for the Shasta Dam were installed at Grand Coulee to hurry the generator installation schedule. Water is pumped