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 MWAK constructed Mason City in 1934. Mason city contained a hospital, post office, electricity and other amenities along with a population of 3,000. Three-bedroom houses in the city were rented for $32 a month. Of the two living areas, Engineer's City was considered to have the better housing. Several other living areas formed around the construction site in an area known as Shack Town, which did not have reliable access to electricity and the same amenities as the other towns. Incorporated in 1935, the city of Grand Coulee supported workers as well and is just west of the dam on