G- Grand Coulee Dam

The Grand Coulee is an ancient river bed on the Columbia Plateau created during the Pliocene Epoch (Calabrian) by retreating glaciers and floods. Originally, geologists believed the Grand Coulee was formed by a glacier diverting the Columbia River but it was revealed in the mid-late 20th century that massive floods from Lake Missoula carved most of the gorge. The earliest known proposal to irrigate the Grand Coulee with the Columbia River dates to 1892, when the Coulee City News and The Spokesman Review reported on a scheme by a man named Laughlin McLean to construct a 1,000 ft dam across the Columbia River, high enough that water would back up into the Grand Coulee. A dam that size would have its reservoir encroach into Canada, which would violate treaties. Eventually, the state allow the dam to be built. 

"Grand Coulee Dam." Wikipedia. Wikimedia Foundation, 27 Jan. 2013. Web. 29 Jan. 2013. <http://en.wikipedia.org/wiki/Grand_Coulee_Dam>.