444 ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 3 5 



severe desert climate, the three-dimensional obstacle of transporta- 

 tion to the canyon and down 800 feet to the canyon floor, and the 

 difficulties of working in and on the sheer walls. Allied with men 

 were the knowledge gained from winning many similar battles, an 

 ideal site for the huge dam, and directly at hand the development 

 and use of modern machinery. 



Work was started in Black Canyon the day after the first appro- 

 priation was made available. Surveys were conducted by aerial 

 and ground photography and later supplemented by detailed sur- 

 veys of the canyon walls, in which latter work transits necessarily 

 were set at hazardous points along the cliff, and the rodmen were 

 lowered by ropes from canyon rims — at times swinging inward 

 pendulum fashion to secure shots under overhangs, while a sheer 

 drop of 500 feet lay below. 



Specifications and drawings were being prepared in the Denver 

 Office of the Bureau of Reclamation, in anticipation of the award 

 of the principal labor contract in the fall of 1931. However, unem- 

 ployment conditions were becoming stringent, and word came from 

 Washington to rush the work to the greatest extent in order to assist 

 in relieving the situation. Drafting forces were increased, designers 

 worked night and day, and by Herculean efforts the major contract 

 for construction of the dam, power plant, and appurtenant works 

 was awarded to the lowest bidder (Six Companies, Inc.) on March 

 11, 1931, 6 months ahead of tlie date originally set. This was the 

 largest labor contract ever awarded by the United States Gov- 

 ernment, the bid amounting to $48,890,995.50. Six Companies, Inc., 

 is composed of six West coast contracting firms, who pooled their 

 assets for the particular work at Black Canyon. 



Care of the workers presented problems requiring earnest thought. 

 Shade temperatures in Black Canyon rise to 130° F., the daily mean 

 rests for weeks above 100°, metal left in the sun burns to the touch, 

 and the black walls of the canyon throw off furnace-like waves of 

 heat. After studying climatic and soil conditions, a location was 

 chosen on a ridge 7 miles from the dam site where the beautiful 

 little town of Boulder City is now situated. Here are clean paved 

 streets, grass and shrubbery to break the sun's reflected glare, and 

 homes, dormitories, and offices built to give maximum comfort in the 

 summer heat. Water from the muddy Colorado is desilted, pumped 

 2,000 feet in elevation, softened and sterilized by chemicals and sup- 

 plied through an efficient distribution system to Boulder City 

 dwellers as a clear sparkling liquid. Electricity, brought 222 miles 

 across desert and mountains, from California for construction 

 power, also supplies the town with light and power. In the fall of 

 1931, the site of Boulder City was raw desert waste, but a year later 



