Hoover Dam

Hoover Dam is famous for many different reasons. It is one of the industrial wonders of the world, a triumph of engineering. It transformed the American southwest by generating power and providing water in times of drought. It created Lake Mead, which provides 110 miles of water recreation. Finally, Hoover Dam provided a needed economic boost to the Las Vegas area during the darkest times of the Great Depression.

The Colorado River acts as the border between Arizona and Nevada, and the dam sits on the Colorado, just east of the town of Boulder City, Nevada, about 30 miles southeast of Las Vegas. Hoover Dam receives around 10 million tourists each year who marvel at the enormous size of the massive, concrete structure, that holds back 28,5 million acre-feet of water. Hoover Dam is the fifth busiest National Park in the United States. A visitors’ center and gift shop on the Nevada side of the dam provides tours of the inner workings of the dam and power plant.

The natural setting of the dam is the Black Canyon of the Colorado River. The dam rises 726 feet from the canyon floor and spans 1,244 feet across at the top. It is 45 feet thick at the top and 660 feet thick at the bottom.

The dam is named after Herbert Hoover, who pushed for its construction in the 1920’s when he was Secretary of Commerce under Warren G. Harding. Construction began when he was President of the United States. Long before construction began, the project had been called the Boulder Dam after the nearby Boulder Canyon, which was thought to be a pref-erable site. The name “Boulder Dam” remained even after the site was moved, and continued as the official name until Congress acted to honor the President. Hoover Dam was the creature of a special commission, formed in 1922 by the federal government and the water consuming states of the southwest. Hoover, who represented the federal government on the commission, was able to organize a water sharing agreement among the different western states. This arrangement, called the “Colorado River Compact” or “Hoover Compromise,” is still in effect today. It was the political breakthrough that permitted a cooperative effort on the Colorado River. Congress passed legislation approving the project in 1928, and appropriated funds for it in 1930. Construction began in 1931, providing lots of jobs to the otherwise idle workforce of Clark County and Las Vegas, Nevada. Many workers migrated to the job site, as unemployment was so high elsewhere in the country.

The Colorado River had rushed through the Black Canyon and Boulder Canyon, to continue into Mexico and empty into the Sea of Cortez. Today, the Colorado trickles to nothing well short of the Mexican border.
Frank Crowe, who personally developed many of the innovations needed to build the dam, became president of Six Companies, Inc., a joint venture of some of the nation’s largest construction contractors, who together erected and installed the structure. Six Companies was also the designated contractor to build Boulder City, a town to be located by the job site for all the workers. Six Companies, Inc. forbade gambling, prostitution and alcohol in the town. Today Boulder City is the only place in Nevada where gambling is not legal. In 1969, the city permitted alcohol to be sold and served. The contractors also persuaded the City of Las Vegas to outlaw prostitution, and in 1931 the red light district was closed down.
Construction was complete in 1935, almost two years earlier than planned.

The construction of the dam required first the construction of “cofferdams” to permit the construction of diversion tunnels (56 feet in diameter, lined with 3 feet of concrete), which allowed the waters of the river to pass and leave the construction site dry. Three miles of such tunnels were built on both sides of the river. Excavation to bed rock led to the removal of 1.5 million cubic yards of material. Concrete had to be poured in sections, as a single pour would have caused incredible heat, cracking and crumbling, and a 125-year curing period. Each interlocking pour was about 6 inches deep. Pipes with river water and refrigeration coils were used in each form to cool the concrete as it cured. It is said the concrete is still in the process of curing to this day. The concrete used in the dam would have been enough to make a two-lane highway from New York City to San Francisco Bay.

The generators produce as much as 2,000 megawatts of power. Most of this heads west to the Los Angeles area, more than 250 miles away. The spillways have been used only twice: once for testing and once in 1983 when immense snow runoff flooded the Colorado. Otherwise, all of the water passes through the channels to the turbines of the generators, hitting them at speeds of around 85 miles per hour.

At the end of the project, Architect Gordon B. Kaufman was contracted to spice up the external appearance of the Hoover Dam. He used an Art Deco style popular in the 1930’s to adorn turrets, clock towers and the functional buildings. During non-daylight savings times of the year there is a one hour time difference between the Arizona side and the Nevada side.

The Bureau of Reclamation of the U.S. Department of the Interior is the operator of the facility. It is now a National Historic Landmark.

Lake Mead is named after Elwood Mead, who managed the construction of Hoover Dam.