Reservoir clearing

In 1933, Reclamation began efforts to purchase land behind the dam as far as 151 mi (243 km) upstream for the future reservoir zone. The reservoir, known later as Lake Roosevelt, flooded 70,500 acres (285 km²) and Reclamation acquired an additional 11,500 acres (47 km²) around the future shoreline. Within the zone were eleven towns, two railroads, three state highways, about one hundred and fifty miles of country roads, four sawmills, fourteen bridges, four telegraph and telephone systems, and many power lines and cemeteries. All facilities had to be purchased or relocated, and 3,000 residents were relocated.^[44] The Anti-Speculation Act was passed in 1937, limiting the amount of land farmers could own in order to prevent inflated prices.^[15] The government appraised the land and offered to purchase it from the affected residents. Many refused to accept the offers, and Reclamation filed condemnation suits.^[45] Members of the Colville Confederated and Spokane tribes who had settlements within the reservoir zone were also resettled. The Acquisition of Indian Lands for Grand Coulee Dam Act of June 29, 1940, allowed the Secretary of the Interior to acquire land on the Colville and Spokane Reservations, eventually accounting for 21,100 acres (85 km²).^[46] By 1942, all land had been purchased at market value: a cost of $10.5 million that included the relocation of farms, bridges, highways and railroads. Relocation reimbursement was not offered to property owners, which was common until U.S. laws were changed in 1958.^[45]
In late 1938, the Works Progress Administration began clearing the reservoir zone of trees and other plants. A total of 54,000 acres (220 km²) were cleared. The cut timber was floated downstream and sold to the highest bidder, Lincoln Lumber Company, which paid $2.25 per thousand board feet.^[47] The pace of clearing was accelerated in April 1941 when it was declared a national defense project, and the last tree was felled on July 19, 1941. The felling was done by Reclamation Supervising Engineer Frank A. Banks and State WPA Administrator Carl W. Smith during a ceremony.^[48] A total of 2,626 people living in five main camps along the Columbia worked on the project. When it was finished, $4.9 million had been spent in labor.^[49]

Labor and supporting infrastructure

Workers installing a penstock section

Workers building the dam received an average of 80¢ an hour; the payroll for the dam was among the largest in the nation. The workers were mainly pulled from Grant, Lincoln, Douglas, and Okanogan counties and women were allowed to work only in the dorms and the cookhouse.^[50] Around 8,000 people worked on the project, and 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.^[17][51][52] Construction conditions were dangerous and 77 workers died.^[22]
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 located directly downstream of the construction site on the west side of the river.^[26] Opposite Engineer's Town, 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.^[53] Of the two living areas, Engineer's City was considered to have the better housing.^[54] 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.^[55] Incorporated in 1935, the city of Grand Coulee supported workers as well and is located just west of the dam on the plateau.^[56] MWAK eventually sold Mason City to Reclamation in 1937 before its contract was completed.^[57] In 1956, Reclamation combined both Mason City and Engineer's Town to form the city of Coulee Dam. It was incorporated as a city in February 1959.^[54]

Irrigation pumps

With the onset of World War II, power generation was given priority over irrigation. In 1943, Congress authorized the Columbia Basin Project and the Bureau of Reclamation began construction of irrigation facilities in 1948. Directly to the west and above the Grand Coulee Dam, the North Dam was constructed. This dam, along with the Dry Falls Dam to the south, enclosed and created Banks Lake, which covered the northern 27 mi (43 km) of the Grand Coulee. Additional dams, such as the Pinto and O'Sullivan Dams, were constructed alongside siphons and canals, creating a vast irrigation supply network called the Columbia Basin Project. Irrigation began between 1951 and 1953 as six of the 12 pumps were installed and Banks Lake was filled.^[58]