One may say that the site of Grand Coulee Dam was determined centuries ago. Lava, hissing and boiling, fought with angry waters, cooled, and bore plant life; then lava came again, repeating the same cycle in successive periods, until seven flows had been recorded in the dark porous rock, streaked with reds and greens, of the high coulee walls. Centuries passed, and then a great ice sheet, which scientists say was 4,000 feet thick, descended from the North. Tearing the earth’s surface, pushing huge quantities of boulders and gravel before it, the ice sheet moved southward, melting, and forming a mighty flood. The flood boiled over the river’s channels, grinding out great gorges and forming new channels. Temporarily, at the present site of Coulee Dam, the river was diverted from its regular course and roared south across the gently sloping tableland, forming what is now known as the Grand Coulee, a chasm over 50 miles long, 800 feet deep and from 2 to 5 miles wide. It then plunged over the great cataract now known as Dry Falls and rejoined the old channel further to the south. When the great ice mass finally melted away, the river resumed its age-old course, leaving the Grand Coulee high and dry. The dam was irrigated 1,300,000 acres, which had long been desert land.
There were other important factors that determined the site. The junction of the river with the coulee has a natural dam foundation of hard, white granite, over 800 feet deep. Nature also left a measureless quantity of gravel on the bank of the valley. Most important of all was the fact that here, bordering a river whose discharge is more regular throughout the entire year than any other river of the land, and whose runoff is five times as great as that of the Colorado River at Boulder Dam, is a vast stretch of arid land which needs to be irrigated—an authority on reclamation called it “one of the most fertile bodies of irrigable land in this or any other country.”
Despite the natural advantages of the site, construction involved many problems never before confronted by engineers. It was necessary to build a massive structure larger than any ever built before, which would withstand the pressure of water 355 feet deep across a width of 4,300 feet. The Columbia, flowing as fast as 14 miles an hour, had to be diverted from its ancient channel and made to flow through a man-made passage while the foundations were being laid. By means of a tremendous belt conveyor 15,000,000 cubic yards of earth and rock were transported more than a mile to a level 600 feet higher and then dumped into Rattlesnake canyon. A million tons of wet earth had to be frozen by means of great icing tubes to prevent the mass slipping into the excavation area.
Work on Coulee Dam site began with core-drilling in the late summer of 1933. The starting of work on the dam project was hastened by the depression, when funds were allotted for public works to relieve unemployment. The Mason-Walsh-Atkinson-Kerr Company, holding the first contract, began work in October 1934; the first unit was finished early in 1938. The foundation, or so-called “lower dam,” was then in place. The MWAK company joined with other bidders in a new contract to continue construction, forming the Consolidated Builders, Incorporated.
On May 21, 1939, a bucket of concrete was poured which marked the completion of 60 percent of the 10,500,000 cubic yards necessary to complete the dam proper. The dam had already surpassed in size any other man-made construction on the face of the earth. On March 22, 1941, the first generators began to produce Grand Coulee power.
Farmers who located in the reclaimed area bought at prices ranging from $5 to $15 per acre land, which was estimated to be two and one-half times as productive as the average soil. At the time they were be required to pay, over a period of 40 years, without interest, the sum of $88 per acre for water rights, plus $3.19 per acre maintenance charges. Their houses were lighted and heated by cheap electricity.
