Columbia Basin Project were built at the north and south ends of Grand Coulee, the dry canyon south of Grand Coulee Dam, allowing the coulee to be filled with water pumped up from the Columbia River. The resulting reservoir, called Banks Lake, is about long. Banks Lake serves as the CBP's initial storage reservoir. Additional canals, siphons, and reservoirs were built south of Bank Lake, reaching over . Water is lifted from Lake Roosevelt to feed the massive network. The total amount of the Columbia flow that is diverted into the CBP at Grand Coulee varies a little from year to year, and
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