OCR

This channel was blasted and carved from rock leading from a point upstream directly through the left dam abutment. The giant ditch served first for diversion of the river and permanently remained as the river's course. The power intake consists of five 22-foot diameter plate steel penstocks set in a concrete wall, 170 feet high, that forms the right side of the forebay. The penstocks feed five generating units having a combined capacity of 225, 000 kilowatts. Diversion of the river was possible after the spillway and forebay walls were high enough to accommodate the flow of the river, regulated to a manageable level by upstream Hoover Dam. With the river flowing through its new channel, work started on the dam itself. A. cutoff trench 50 feet deep was excavated the length of the dam and 450,000 cubic yards of unsuitable material were removed to make way for the dam's base. Impervious clay was hauled from downstream pits, placed in the dam, and compacted by sheep's-foot rollers. Then semi-impervious rock and an outer layer of coarser rock was placed to complete the dam. Special precautions had to be taken in the 120-degree summer heat to cool the aggregate and cement used in Davis concrete structures. Aggregate bins were dug in the hillsides and shaded by frame buildings, constantly sprayed with ice water. One thousand gallons an hour of river water for concrete was pumped through an ammonia compressor system, cooling it to 35 degrees; then crushed ice was added to the concrete mix from three machines producing 60 tons daily. A highly efficient system of handling concrete started at the storage bins where a conveyor line carried material from an aggregate tunnel under the bins to the mixing plant. The mix was dumped into concrete buckets, set four on a flat car that ran on the craneway to be picked up by 200 ton whirley cranes, and placed in the powerhouse, spillway and forebay. Davis Dam was built for the Bureau of Reclamation by an association of contractors including Utah Construction & Mining Co. (sponsor), Morrison-Knudsen Co., Inc., General Construction Company, Pacific Bridge Company, K & E Corporation, Winston Brothers Company, Henry J. Kaiser Company, The Kaiser Company, Kaiser Engineers, Inc. , J. H. Pomeroy & Co., Inc., and Raymond Concrete Pile Company. This project was completed in 1951 and the approximate cost was $31,320,000. The Bureau of Reclamation also has a purchasable book devoted to this subject if more information is needed. Grassy Trail Dam: This dam is located in the State of Utah, and was completed in 1951. The owner of this earthfill project was Columbia-Geneva Steel Co. and they engineered the project also. Approximate cost of the project was $385,000.