Grand Coulee Grand Coulee The Grand Coulee is an ancient river bed in the U.S. state of Washington. This National Natural Landmark stretches for about 60 miles (100 km) southwest from Grand Coulee Dam to Soap Lake, being bisected by Dry Falls into the Upper and Lower Grand Coulee. The Grand Coulee is part of the Columbia River Plateau. This area has underlying granite bedrock, formed deep in the Earth's crust 40 to 60 million years ago. The land periodically uplifted and subsided over millions of years giving rise to some small mountains and, eventually, an inland sea. From about 10 to
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