Skip to main content
Select Source:

Hoover Dam

Hoover Dam

In 1928, the U.S. Congress authorized the Boulder Canyon Project, later known as Hoover Dam. The project's success helped usher several decades of major water projects funded by the U.S. government.

Hoover Dam is located on the border between Arizona and Nevada. It is within Black Canyon on the Colorado River, near Las Vegas. The construction of Hoover Dam began in 1931. When completed in 1936, the dam was a major engineering achievement at a height of 221 meters (726 feet) and crest-width of 379 meters (1,244 feet).

The reservoir that formed behind the dam is Lake Mead, one of the world's largest artificially created bodies of water. It covers an area of 603 square kilometers (233 square miles), and its shoreline measures 885 kilometers (550 miles). The hydroelectric generators of Hoover Damcapable of supplying nearly 1.5 million kilowatts of powerprovide electricity to Arizona, southern California, and Nevada.

Construction and Benefits

Before the construction could start, the Colorado River had to be diverted through tunnels. These tunnels would allow the water to bypass the site of the dam foundation, and later would contain the electric plant generators. Building tunnels directly through the canyon rock walls required huge amounts of dynamite in order to remove rock, and enormous support structures to maintain the passageways. Once the first two tunnels where in place, cofferdams were built to divert the Colorado River. This accomplishment signaled that the actual dam construction could begin.

Base Surface.

Because of its importance in the overall integrity of the dam, the foundation was a major factor in building a structure that would be assured not to fail. This necessitated the removal of the mud and muck at the river bottom. Workers with the assistance of power shovels excavated over 382,300 cubic meters (500,000 cubic yards) of these deposits in order to reach bedrock , sometimes over 12 meters (40 feet) below. At the same time, workers called "high scalers" blasted the walls to create a smooth joining surface for the dam.

Pouring Concrete.

On June 6, 1933, the pouring of concrete began at the dam's base. Two-hundred-thirty blocks of concrete, totaling a volume of 2.49 million cubic meters (3.25 million cubic yards), were used to complete the base on May 29, 1935. This pouring process was necessary to allow the concrete to properly dry. It was stated that enough concrete was used to pave a 4.9-meter (16-foot) wide highway from San Francisco to New York City. The filling of Lake Mead now began.

Why Build?

The main reason for building Hoover Dam was to supply the electrical power necessary to transport 4.4 million acre-feetover a quarter of the Colorado River's average annual flowto California. Soon, the dam also would supply water to Las Vegas, whose revenue would be used to finance more water projects. Hoover Dam also allowed waterworks along the lower Colorado to be safely constructed and maintained as they operated upstream on a (now) tamely flowing river.

Benefits and Impacts.

Because of Hoover Dam, the Colorado River was controlled for the first time in history. Farmers received a dependable supply of water in Nevada, Arizona, and California. Numerous cities such as Los Angeles, San Diego, and Phoenix were given an inexpensive source of electricity, permitting population growth and industrial development. Hoover Dam also provided for flood control and irrigation . Even prior to its completion however, concerns were expressed over the potential impacts of Hoover Dam on aquatic systems.

Research performed in the ensuing years shows that significant changes have occurred to the chemical, physical, and biological processes of associated ecosystems , including declines in species of fish. Hoover Dam dramatically altered the hydrologic regime of the Colorado River, for example. Prior to the 1930s, it carried approximately 125 million tons of suspended sediment to its delta at the head of the Gulf of California. At present, the Colorado River does not discharge either sediment or water to the gulf.

see also Bureau of Reclamation, U.S.; Colorado River Basin; Dams; Economic Development; Fish and Wildlife Issues; Hydroelectric Power; Instream Water Issues; Reservoirs, Multipurpose.

William Arthur Atkins

Bibliography

Stevens, Joseph E. Hoover Dam: An American Adventure. Norman, OK: University of Oklahoma Press, 1988.

Internet Resources

Hoover Dam: An Engineering Wonder of the World. <http://www.sunsetcities.com/hoover-dam.html>.

Hoover DamNational Historic Landmark. Bureau of Reclamation, U.S. Department of the Interior. <http://www.hooverdam.usbr.gov/>.

Simonds, William Joe. "The Boulder Canyon Project: Hoover Dam." Bureau of Reclamation History Program. Bureau of Reclamation, U.S. Department of the Interior. <http://www.usbr.gov/history/hoover.htm>.

HOOVER OR BOULDER?

Construction of the concrete arch-gravity type dam began as part of the Boulder Canyon project. Originally named after President Herbert Hoover, the dam was later called Boulder Dam, but in 1947 its initial name was restored.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"Hoover Dam." Water:Science and Issues. . Encyclopedia.com. 22 Aug. 2017 <http://www.encyclopedia.com>.

"Hoover Dam." Water:Science and Issues. . Encyclopedia.com. (August 22, 2017). http://www.encyclopedia.com/science/news-wires-white-papers-and-books/hoover-dam

"Hoover Dam." Water:Science and Issues. . Retrieved August 22, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/news-wires-white-papers-and-books/hoover-dam

Hoover Dam

HOOVER DAM

HOOVER DAM. Located in the Black Canyon on the Colorado River, Hoover Damlies about thirty miles southeast of Las Vegas, Nevada. The federal government built it for flood control, navigation, irrigation, water storage, and power generation. Farmers in the region experienced disastrous Colorado River floods before the dam was constructed.

Herbert Hoover first proposed a dam for the Colorado River when he became secretary of commerce in 1921. At the time his plan involved a dam in Boulder Canyon. After he became president, Hoover proposed an "upper" and a "lower" basin, a compromise that made a dam possible by dividing the water among the states affected


by the river and its tributaries. Arizona, California, Colorado, Nevada, New Mexico, Utah, and Wyoming entered the Colorado River Compact in 1922, and in 1928 Congress authorized the construction of Boulder Dam, which later became the Hoover Dam.

During the Great Depression the government contractor, Six Companies, six formerly independent companies that had merged to get the job, constructed the dam, the highest concrete arch dam in the United States. Lake Mead, the reservoir the dam impounds, is one of the largest human-made lakes in the world, with an area of 247 square miles. The dam itself is 726.4 feet from the foundation rock on the roadway to the crest, with towers and ornaments extending another 40 feet above the crest. It weighs more than 6.6 million tons. With 17 turbines, the power facility has a nameplate capacity of 2.074 million kilowatts.

Of the thousands of people who worked on the dam between 1930 and 1936, ninety-six workers died from accidents directly relating to the building of the dam and dozens more from related ailments. Before the dam could even be started, Boulder City had to be built to house the workers, and miles of highways and railroads from the dam site to Boulder City and from there to Las Vegas had to be constructed. In the first step of building the dam, men attached to ropes were hoisted over the edge of the canyon, where they scraped loose rock from the canyon walls by hand. Four tunnels diverted the flow of the river, and a ton of dynamite was required to dig fourteen feet. The dam itself was made up of columns filled slowly with concrete. To cool the chemical heat released by the concrete, ice water ran through the equivalent of 582 miles of one-inch diameter pipes embedded in the concrete. After the columns were filled and cooled, grout was poured between them to make the structure monolithic.

The Hoover Dam was seen as a triumph of humans over nature. It was the first human-made structure to exceed the masonry mass of the Great Pyramid of Giza. By the twenty-first century the dam was regarded ambivalently, sustaining environmentalists' criticism that it in fact damaged or destroyed an ecosystem.

BIBLIOGRAPHY

Carothers, Steven W., and Bryan T. Brown. The Colorado River through Grand Canyon: Natural History and Human Change. Tucson: University of Arizona Press, 1991.

Dunar, Andrew J., and Dennis McBride. Building Hoover Dam: An Oral History of the Great Depression. New York: Twayne, 1993.

Stevens, Joseph E. Hoover Dam: An American Adventure. Norman: University of Oklahoma Press, 1988.

RuthKaplan

See alsoConservation ; Hydroelectric Power .

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"Hoover Dam." Dictionary of American History. . Encyclopedia.com. 22 Aug. 2017 <http://www.encyclopedia.com>.

"Hoover Dam." Dictionary of American History. . Encyclopedia.com. (August 22, 2017). http://www.encyclopedia.com/history/dictionaries-thesauruses-pictures-and-press-releases/hoover-dam

"Hoover Dam." Dictionary of American History. . Retrieved August 22, 2017 from Encyclopedia.com: http://www.encyclopedia.com/history/dictionaries-thesauruses-pictures-and-press-releases/hoover-dam

Hoover Dam

Hoover Dam, 726 ft (221 m) high and 1,244 ft (379 m) long, on the Colorado River between Nev. and Ariz.; one of the world's largest dams. Built between 1931 and 1936 by the U.S. Bureau of Reclamation, the dam is named for President Herbert Hoover; from 1933 to 1947 it was known as Boulder Dam. A key unit on the Colorado, the dam is a major supplier of hydroelectric power and provides for flood control, river regulation, and improved navigation. Hoover Dam impounds Lake Mead, the largest reservoir in the United States; water is used to irrigate more than 650,000 acres (263,000 hectares) in S California and Arizona, and c.400,000 acres (162,000 hectares) in Mexico. The nearby O'Callaghan-Tillman Memorial Bridge (2010), with the longest concrete arch, 1,079 ft (329 m), in the United States, crosses the river below the dam. Hoover Dam is part of Lake Mead National Recreation Area (see National Parks and Monuments, table). Boulder City, Nev., was built to house workers on the project.

See J. E. Stevens, Hoover Dam (1988).

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"Hoover Dam." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. 22 Aug. 2017 <http://www.encyclopedia.com>.

"Hoover Dam." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (August 22, 2017). http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/hoover-dam

"Hoover Dam." The Columbia Encyclopedia, 6th ed.. . Retrieved August 22, 2017 from Encyclopedia.com: http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/hoover-dam

Hoover Dam

Hoover Dam One of the world's largest dams, on the Colorado River between Arizona and Nevada, USA. Opened in 1935, its waters irrigate land in s California, Arizona, and Mexico. Height: 221m (726ft). Length: 379m (1244ft).

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"Hoover Dam." World Encyclopedia. . Encyclopedia.com. 22 Aug. 2017 <http://www.encyclopedia.com>.

"Hoover Dam." World Encyclopedia. . Encyclopedia.com. (August 22, 2017). http://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/hoover-dam

"Hoover Dam." World Encyclopedia. . Retrieved August 22, 2017 from Encyclopedia.com: http://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/hoover-dam