Glacial Lake Columbia Glacial Lake Columbia Glacial Lake Columbia was the lake formed on the ice-dammed Columbia River behind the Okanogan lobe of the Cordilleran Ice Sheet when the lobe covered of the Waterville Plateau west of Grand Coulee in central Washington state during the Wisconsin glaciation. Lake Columbia was a substantially larger version of the modern-day lake behind the Grand Coulee Dam. Lake Columbia's overflow – the diverted Columbia River – drained first through Foster Coulee, and as the ice dam grew, through first Moses Coulee, and finally, the Grand Coulee. The Cordilleran ice sheet also blocked the Clark Fork River and
Grand Coulee Dam Frank A. Banks served as the chief construction engineer. Bert A. Hall was the chief inspector who would accept the dam from the contractors. Orin G. Patch served as the chief of concrete. Construction conditions were dangerous and 77 workers died. To prepare for construction, housing for workers was needed along with four bridges downstream of the dam site, one of which, the Grand Coulee Bridge, exists today. The Bureau of Reclamation provided housing and located their administrative building at Engineer's Town, which was directly downstream of the construction site on the west side of the river. Opposite Engineer's Town,