Statement of Floyd E. Dominy, Commissioner of Reclamation, Before the Subcommittee on Irrigation and Reclamation Committee on Interior and Insular Affairs, U.S. Senate on S. 1658

Document: Statement of Floyd E. Dominy, Commissioner of Reclamation, Before the Subcommittee on Irrigation & Reclamation, Committee on Interior & Insular Affairs, U.S. Senate on S. 1658, page 18Bridge Canyon Dam has been completely redesigned to take advantage of significant advancements in technology that have occurred since 1947. It has been redesigned as a variable-radius, thin-arch structure, with a minimum thickness at the base of about 148 feet as compared to an original base thickness of over 600 feet. This dam would have a structural height of about 740 feet above foundation. In redesigning Bridge Canyon Dam as a thin arch, the quantities of concrete were reduced from 5,700,000 cubic yards to 2,650,000 cubic yards. The cost of the redesigned dam is estimated at about $119 million at current price levels, as compared with an estimated cost for the original design of about $261 million at these price levels. The installed capacity of the powerplant was increased from 750,000 kilowatts to 1,500,000 kilowatts. This change was made to take advantage of the upstream regulation provided by the subsequent construction of Glen Canyon Dam upstream. With the river controlled upstream at Glen Canyon Dam and immediately downstream at Hoover Dam, Bridge Canyon powerplant can be operated at high head as a peaking operation. The Bridge Canyon powerplant would have a load factor of about 37 percent for commercial generation. By operating Bridge Canyon powerplant as a peaking facility, under normal operations the reservoir will fluctuate only about 4 feet. Thus a stable pool of deep, still water in one of the most spectacularly scenic canyons of the world will be maintained. Its recreational potential is accordingly 18Epson Perfection 4870 Photo, 400 dpi, 8 bit, 781,173 byte