In the early 20th century, the U.S. Bureau of Reclamation designed a massive dam dividing the Colorado River at the border of Arizona and Nevada to fully supply water resources in the Southwestern United States. During construction, workers faced many challenges. To level and clear the canyon walls, construction workers had to work at a height of 250 meters. In 1935, at the time of completion, Hoover Dam was the largest dam in the world, becoming a national historic landmark as well as a popular tourist destination.
The idea of building a giant dam was first voiced in 1922. Arthur Powell Davis, director of the U.S. Bureau of Reclamation, proposed to Congress a plan to build a dam in Black Canyon, located on the border of Arizona and Nevada. According to Davis’s plan, the dam could not only control water flows, provide water to many cities, but also generate hydroelectric power, the profits from the sale of which would cover the cost of building the dam.
To approve the project, called Boulder Canyon, a group of 8 people was assembled, seven representatives of the states that make up the Colorado River basin, as well as a representative of the federal government – Secretary of Commerce Herbert Hoover. The six state representatives (Colorado, Wyoming, Utah, New Mexico, Arizona, and Nevada) were concerned about the distribution of Colorado River water among the states and that the water would go to California first. This controversy continued until the end of Calvin Coolidge’s presidency.
The bill to build the dam was signed into law in December 1928. At the same time, Secretary of the Interior Ray Wilbur announced that the plat would be named after the new President of the United States, Herbert Hoover.
Construction of the Hoover Dam began during the Great Depression. Construction workers, hoping to get a job, camped out in the desert near Las Vegas. The lucky ones who got jobs settled in Boulder City, a small community built specifically to house the dam’s builders and engineers. Interestingly, Boulder City is still the only city in the state of Nevada where gambling is prohibited.
To prepare the site for the construction of the dam, it was necessary to divert the waters of the Colorado River. To carry out such an operation, the builders had to drill four derivation tunnels with a dimeter of 17 meters. To meet the tight deadline, the workers, suffocating from hydrogen oxide and dust, drilled relentlessly through solid rock. As a consequence, many workers were disabled and some died.
The second phase of dam construction, was the clearing of waste rock from the canyon walls. The construction workers, whose job it was to locate and remove the weak rock from the cliff, were secured by straps at 250 meters high. Wielding 20-kilogram jackhammers, the construction workers knocked down the top ball of rock to reach the rock’s hard parts. This dangerous work took many lives.
Interesting Fact: The construction of the Hoover Dam was the first construction site in which construction workers, as a means of protection, used helmets.
About 600,000 tons of cement, 3.5 million cubic meters of fill and 20,000 tons of rebar were used to build the 221-meter dam. These materials would have been enough to build a road from New York to San Francisco. To make concrete, concrete plants were built near the dam site. More than 21,000 laborers participated in the construction of the dam. The maximum number of construction workers working at the same time was 5,251. A total of 96 people died during the construction of the Hoover Dam.
The construction of the dam was completed 2 years ahead of schedule. On September 30, 1935, the opening ceremony of the Hoover Dam took place, 20,000 people witnessed the symbolic ribbon cutting by Franklin D. Roosevelt.
Thanks to the Hoover Dam, the Colorado River became the main source of water for cities such as Los Angeles, Las Vegas, and Phoenix. The 17 turbines generate enough electricity to power 1,300,000 homes.
In 1985, Hoover Dam was listed as a National Historic Landmark, and in 1994 it became one of the Seven American Wonders of Engineering. About 7 million tourists come to see the structure each year, while Lake Mead, the largest man-made reservoir in the world created by the construction of the Hoover Dam, is a popular vacation destination for 10 million tourists a year.