The 31-Mile Grand Coulee tunnel

A proposal to build a 31-mile water tunnel under the Grand Coulee was made by Frank Harris, a civil engineer from Renton. His plan, publicly announced in December 1935, was to expedite the irrigation of approximately 500,000 acres of land in the Columbia Basin by a gravity system, without waiting for Grand Coulee power. He figured that the amount of water required to lift and fill what is now Bank...