OCR

Grand Coulee is a straight-gravity dam, built for the Bureau of Reclamation to provide water storage, power production, flood control, navigation im- provements, and the eventual irrigation of 1,000,000 acres in the area south of the dam site. Consolidated Builders, which performed the completion contract (sometimes known as the "high dam") included Henry J. Kaiser Company (sponsor); Morris on-Knudsen, J. F. Shea Co., Inc.; MacDonald & Kahn, Inc.; Pacific Bridge Company; Utah; and General Construction Co, The former large contract had been completed by an association of Silas Mason Co., Walsh Construction Co., and Atkinson-Kier Co., whose members were also participants in Consolidated Builders. Grand Coulee Dam was completed in 1941, but the reservoir waters were still hundreds of feet below the level of irrigable lands, in 1948 a joint venture of Morrison-Knudsen (sponsor) and Peter Kiewit Sons Company was awarded two contracts by the Bureau of Reclamation to complete the east powerhouse and build the Grand Coulee pumping plant. This and related work was designed to supply power for pumps to draw water from the reservoir to irrigate ultimately 1,000,000 acres. The combined output of Grand Coulee's east and west powerhouses (each has nine generators) is 1,974,000 kilowatts. Work to complete the east powerhouse included the installation of draft tubes and piping and the concrete foundations for nine operators. Eight of the ultimate of nine generators were embedded in concrete. Morrison- Knudsen and Peter Kiewit built the powerhouse control bay, a steel- reinforced concrete building 85 feet high and 102 feet long, to house offices and regulating switchboards. From it to the steel-towered switchyard a total of 1, 800 feet of tunneling was completed, 300 feet driven underground, 1, 500 feet done by cut-and-cover, Grand Coulee pump house is in a hugh cavern left behind the right-angle wing dam built by the dam builders. The pump house rises from, bedrock to the height of a 20-story building and is longer (600 feet) than a city block. MK-PK also built the stalls for the 12 huge pumps that draw water from the reservoir through conduits in the wing dam and drive it upward through 12 hugh pipes on a vertical lift of 280 feet. From the outlet works the water flows in a 3,500-foot long canal into a reservoir created by two earth- dikes across Grand Coulee, the ancient water course of the- river. Grand Coulee's 65,000 housepower irrigation pumps are the largest that man had ever made. One alone, discharging 700, 000 gallons of water a minute, could supply the population of New York City every 24 hours. Six of these total of 12 had been installed by the Bureau in 1953. Approximate cost of this project was $65, 000, 000.