LAKE MEAD Construction of Boulder Dam

LOCATION

Boulder Dam* is being built by the United States Government in the Black Canyon of the Colorado where the river forms the boundary between the states of Nevada and Arizona. The location is 410 miles from the Gulf of California, 267 miles downstream from Bright Angel crossing in Grand Canyon, 30 miles southeast of Las Vegas, Nevada, and 7 miles northeast of Boulder City.

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*Web Edition Note: Boulder Dam was officially renamed Hoover Dam on April 30, 1947.

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Black Canyon, 1921

THE BUILDERS

The Bureau of Reclamation, a part of the Department of Interior, furnishes complete designs, lays out and stakes all structures, exercises general supervision of construction, maintains close inspection of all project operations, furnishes all materials, and makes payment to the contractor at monthly intervals for work completed.

Contracts are awarded to lowest bidders for actual construction on the project and for furnishing all materials that form a part of the permanent structures. The principal labor contracts were awarded to Six Companies, Inc., of San Francisco, California, for building the dam, power plant and appurtenant works, at a bid price of approximately $10,000,000.00 and with The Babcock & Wilcox Company of Barberton, Ohio, on its bid of approximately $11,000,000 for furnishing and erecting the plate steel pipes to be used to supply water to the turbines of the power plant or otherwise regulate the flow of water from the reservoir.

Panoramic perspective of construction activities and area adjacent to Boulder Dam. From U.S. Department of the Interior, Bureau of Reclamation—Boulder Canyon Project: Arizona- California - Nevada.

MATERIALS REQUIRED

Quantities of materials to be removed or placed during construction include 9,000,000 tons of rock excavation, which if placed in a masonry wall, similar to those on the project, would extend 2,100 miles; more than a million cubic yards of river fill excavation, equivalent to digging a trench 100 feet wide, a mile long, and 60 feet deep; and over 4,000,000 cubic yards of concrete, sufficient to build a 20-foot wide pavement extending from California to Florida.

Supplies for building the huge structure include 1,000,000 barrels of cement, 165,000 cars of sand, gravel and cobbles, 35,000 tons of structural and reinforcing steel, 900 cars of hydraulic machinery, and over 3,000 miles of steel pipe. If the total materials and construction equipment were placed in one train, the engine would be arriving at Boulder City as the caboose left Kansas City, Missouri.

Boulder Dam and Appurtenant Works. (click on image for a PDF version)

COST

The estimated cost of construction is $120,000,000.00 including $11,200,000.00 interest charges for the period in which the project is liquidated. Contracts for power have been signed by the City of Los Angeles, and other municipalities, the Southern California Edison Company and the Metropolitan Water District of Southern California that will insure revenues to pay all construction charges and interest in less than 50 years.

East Section, Boulder City

West Section, Boulder City

PREPARATORY CONSTRUCTION

In order to move the immense amounts of materials and heavy equipment required, secure ready access to the canyon activities, furnish cheap construction power, and provide livable quarters for the workers in the desert climate, it was necessary to build railroads and highways, a long electrical transmission line, and the construction camp of Boulder City.

Standard gauge tracks were laid by the Union Pacific Railroad from its main line to Boulder City, lengthened by the Bureau of Reclamation to the top of the damsite and later extended by Six Companies, Inc., to the bottom of Black Canyon and to all its plants, completing the 52 miles of line that serves the project. At the peak of construction, 300 cars of materials were carried by rail to the dam and appurtenant works every 24 hours.

Paved roads lead from U. S. Highway 91 at Las Vegas to Boulder City, 23 miles to the southeast, and thence to the top and bottom of Black Canyon. Visitors to the project in 1934 numbered 266,435, and nearly 40,000 in February, 1915.

A transmission line, 222 miles in length and operated at 88,000 volts, brings electrical energy from San Bernardino, California, to a substation near the top of the Nevada dam abutment, where it is distributed to Boulder City and construction features at 2,300 volts. The government and contractor used more than 4,000,000 K.W.H. of electricity each month, costing in excess of $45,000.00.

Government Administration Building

Government Residences

The construction camp of Boulder City has been laid out at a location seven miles from Black Canyon and 2,000 feet in elevation above the river channel, where the climatic and soil conditions are the most desirable in the vicinity of the damsite. The governmental section of the town is built in a permanent manner, as it will be used to accommodate those employed at the dam, power house and reservoir after they are completed. All land in and near Boulder City is government owned and the contractors, permittees for business enterprises, and non-government residents lease the ground on which their buildings are located. The area is under strict supervision and regulations are enforced by a body of Federal Rangers.

The population has been as great as 6,000 persons, of whom 40 per cent of the men were unmarried. The large dormitories of Six Companies, Inc., were air cooled and heated, and accommodated 172 men, each in a single room. The mess hall, operated by Anderson Brothers Supply Company, has seating facilities for 1,300 men and has served during seven times a day, a total of nearly 6,000 meals. Each single man was charged $1.60 a day for meals, room, and transportation to and from the canyon. Married men rented houses from the contractor at rates varying from $15.00 to $50.00 for two to six-room houses unfurnished, and could buy their food and other supplies locally. The government and contractors employed as many as 5,250 men at one time, the gross monthly payroll exceeding $750,000.00.

One of the Mess Halls

Dormitory (left); 150-Man Transport (right)

The water supply for the town is procured from the Colorado River. Starting from the intake pumps, carrying an average content of 6,000 parts per million of silt and 350 parts per million of hardness the water passes through a desilting plant, and is pumped 1,800 feet in elevation through a six-mile pipe line to a modern filtration plant. Here it is softened by the addition, principally, of soda ash and hydrated lime, is filtered through sand beds and then chlorinated before being lifted an additional 200 feet to a 2,000,000-gallon distribution tank on the hill north of the town. The per capita consumption is approximately 190 gallons per day during the summer months and 130 for the year.

Cableways Nos. 5 and 6

Skip Load of Men (left); Load of Concrete (right)