The Hoover Dam Story
On December 21, 1928, President Calvin Coolidge signed the Boulder Canyon Project Act for “…controlling the floods, improving navigation and regulating the flow of the Colorado River, providing for storage and for the delivery of the stored waters thereof for reclamation of public lands and other beneficial uses exclusively within the United States, and for the generation of electrical energy…”

The act sought to dam the Colorado River and distribute its water for use in Arizona, California, Colorado, Nevada, New Mexico, Utah, and Wyoming.
Considered a wonder of civil engineering, the concrete arch-gravity Hoover Dam was constructed in Black Canyon on the Colorado River, on the Arizona-Nevada border. Often referred to as Boulder Dam, the site was officially named after Herbert Hoover in 1947. Previously a mining engineer, Hoover was actively engaged in the dam’s development and the distribution of its water rights.

In 1869, Civil War veteran Major John Wesley Powell was the first person on record to travel the length of the Colorado River. As head of the U.S. Geographical and Geological Survey of the Rocky Mountain region, Powell was also one of the first to describe the Southwest’s geography in his work Report on the Lands of the Arid Region of the United States.
In 1900, William E. Smythe envisioned an irrigated desert in The Conquest of Arid America. This publication generated much popular support for the Newlands Reclamation Act signed in 1902 by President Theodore Roosevelt whose Progressive-era conservation policy linked democratic opportunity to control of natural resources.
When flooding from the Colorado River wiped out nascent farming and irrigation efforts in major portions of the Imperial and Yuma valleys between 1905 and 1916, the die was cast favoring technological control of the river.
Construction centered first on diverting the Colorado through four fifty-foot diameter tunnels, two on each side of the river, driven through the canyon walls—one of the toughest aspects of the project. After constructing housing for both government and contractor employees, a highway from Boulder to the dam site, railroad lines to the dam site, and a power transmission line to supply energy for construction, the dam’s first concrete was poured in June 1933. Two years later, in February 1935, the dam started impounding water into Lake Mead; the last concrete was poured in May that year. All features were completed by March 1, 1936. When President Franklin D. Roosevelt dedicated the dam on September 30, 1935, he said:
…I have the right once more to congratulate you who have builded [sic] Boulder Dam [Hoover Dam], and on behalf of the nation, to say to you: “Well done.”

Learn More
- Search the pictorial collections on the terms construction and dam for related images. See, for example, photographs by FSA/OWI photographer Russell Lee showing the construction of Shasta Dam.
- Historic American Buildings Survey/Historic American Engineering Record/Historic American Landscapes Survey includes several photographs of the Hoover Dam.
- Search the pictorial collections on Hoover Dam or Boulder Dam for dozens of images of construction of the dam.
- The Evolution of the Conservation Movement, 1850-1920 documents the formation and cultural foundations of the effort to conserve and protect America’s natural heritage. Search, for example, on terms such as John Wesley Powell, William Smythe, Theodore Roosevelt, and reclamation to learn more. Also see the related special presentation Documentary Chronology of Selected Events in the Development of the American Conservation Movement, 1847-1920.
- Search on the term reclamation in Theodore Roosevelt: His Life and Times on Film to see film of Roosevelt Dam, another major irrigation project which developed out of Roosevelt’s commitment to the reclamation of desert land.
- Listen to “Personal Greetings from Harry Hansen to Pat and Bogue Ford,” a letter forming part of the field materials documenting the construction of the Deadwood Dam in Idaho and the Boulder Dam in Nevada in California Gold: Northern California Folk Music from the Thirties Collected by Sidney Robertson Cowell. Use the Keyword Search for words in the title.