<P> Even before Congress approved the Boulder Canyon Project, the Bureau of Reclamation was considering what kind of dam should be used . Officials eventually decided on a massive concrete arch - gravity dam, the design of which was overseen by the Bureau's chief design engineer John L. Savage . The monolithic dam would be thick at the bottom and thin near the top, and would present a convex face towards the water above the dam . The curving arch of the dam would transmit the water's force into the abutments, in this case the rock walls of the canyon . The wedge - shaped dam would be 660 ft (200 m) thick at the bottom, narrowing to 45 ft (14 m) at the top, leaving room for a highway connecting Nevada and Arizona . </P> <P> On January 10, 1931, the Bureau made the bid documents available to interested parties, at five dollars a copy . The government was to provide the materials; but the contractor was to prepare the site and build the dam . The dam was described in minute detail, covering 100 pages of text and 76 drawings . A $2 million bid bond was to accompany each bid; the winner would have to post a $5 million performance bond . The contractor had seven years to build the dam, or penalties would ensue . </P> <P> The Wattis Brothers, heads of the Utah Construction Company, were interested in bidding on the project, but lacked the money for the performance bond . They lacked sufficient resources even in combination with their longtime partners, Morrison - Knudsen, which employed the nation's leading dam builder, Frank Crowe . They formed a joint venture to bid for the project with Pacific Bridge Company of Portland, Oregon; Henry J. Kaiser & W.A. Bechtel Company of San Francisco; MacDonald & Kahn Ltd. of Los Angeles; and the J.F. Shea Company of Portland, Oregon . The joint venture was called Six Companies, Inc. as Bechtel and Kaiser were considered one company for purposes of 6 in the name . The name was descriptive and was an inside joke among the San Franciscans in the bid, where "Six Companies" was also a Chinese benevolent association in the city . There were three valid bids, and Six Companies' bid of $48,890,955 was the lowest, within $24,000 of the confidential government estimate of what the dam would cost to build, and five million dollars less than the next - lowest bid . </P> <P> The city of Las Vegas had lobbied hard to be the headquarters for the dam construction, closing its many speakeasies when the decision maker, Secretary of the Interior Ray Wilbur came to town . Instead, Wilbur announced in early 1930 that a model city was to be built in the desert near the dam site . This town became known as Boulder City, Nevada . Construction of a rail line joining Las Vegas and the dam site began in September 1930 . </P>

Who is put in charge of building the dam