Hoover Dam History

Constructed by the Bureau of Reclamation in the depths of the Great Depression in the 1930s, Hoover Dam was the largest federal project of its time. Building the dam was hot, dirty and often dangerous work, but more than 20,000 men were happy to be working on the Hoover Dam, the biggest dam project in the world when it was completed. 

Decades after proposals were made to build a dam to control flooding and provide water for farms in Southern California and the Southwest, then-Secretary of Commerce Herbert Hoover served on a commission charged with finding an equitable way to divide the waters of the Colorado River among the seven basin states. The result of this commission’s deliberations – the Colorado River Compact of 1922 – finally cleared the way for the dam to be built. President Calvin Coolidge authorized the Boulder Canyon Project in 1928. The next year, as the new president, Hoover took an active part in settling engineering problems that moved the dam from Boulder Canyon to Black Canyon. The dam, referred to as Boulder Dam in the 1930s, was officially named Hoover Dam, a name that was restored by a resolution signed by President Truman in 1947. 

Six Companies, a consortium of six smaller contractors, won the construction bid. General Superintendent Frank Crowe devised lights for working at night so that 24-hour shifts were possible, as well as other construction innovations. 

The river first had to be diverted from the work site, and four diversion tunnels were cut into the canyon. High scalers worked on the canyon walls, removing loose rock to make sure the walls were smooth so the dam’s concrete would adhere. After a year, the river was routed through the tunnels, and the main work began. The dam was built in interlocking blocks, and concrete was poured in sections from four- and eight-cubic-yard buckets suspended from cables. 

Six Companies was allowed seven years to build the dam, beginning in 1931, but the dam was completed two years ahead of schedule, and President Franklin D. Roosevelt dedicated the dam on September 30, 1935. 

The need for a bypass bridge at Hoover Dam was identified in the 1960s. This section of U.S. Highway 93 connecting Nevada and Arizona is narrow and steep, rendering it unsafe for the amount of traffic on the road. A major commercial route connecting the two states as well as Utah, U.S. 93 is important to the economies of the region and the nation.

The bypass project was authorized in the 1980s, and public input was solicited in the 1990s. Nevada and Arizona government officials, American Indian tribes and State Historical Preservation Offices were consulted, with an environmental impact study released in 2001. The first phase of construction began a year later. The Mike O’Callaghan-Pat Tillman Memorial Bridge opened to all traffic on Tuesday night, October 19, 2010.

Officially called the Mike O’Callaghan-Pat Tillman Memorial Bridge, the bypass was named after two prominent community leaders from each state. Mike O’Callaghan was a well-known businessman and former governor of Nevada, and Pat Tillman was a professional football player with the Arizona Cardinals who joined the U.S. Army and lost his life in Afghanistan in 2004.

For details and photos of the bridge and its construction, visit “Hoover Dam Bypass US 93”: www.hooverdambypass.org.

*Thanks to the Bureau of Reclamation for factual clarification.