The History of the Hoover Dam

History Hoover Dam

When looking at the history of the Hoover Dam, one must admire the incredible planning that went into its creation. The foresight of the project’s engineers and overseers to create a massive construction project that has stood the test of time is truly remarkable.

The need for the Hoover Dam stems from the vast history of the Colorado River and its unpredictable flood patterns. The development of the American Southwest also played a key and important role in the push for a method to control the river.

Throughout history the Colorado River ebbed and flowed, bringing water from high up in the Rocky Mountains and distributing it amongst its basin across seven US states and Mexico. While the river brought a reliable source of water along its pathway, it was also prone to devastating floods that could wipe out all in its path.

As the United States began development of the American Southwest, in particular southern California, the Colorado River was seen as a potential source of irrigation water. This water could be used to spur agricultural development and encourage more investment and population growth in the region.

As usage and demand of the Colorado River water increased, it was obvious that an agreement to share the water between states was needed. The seven affected states came together in 1922 to form the Colorado River Compact outlining the details of water distribution. Mexico’s water rights were addressed in a later agreement.

With the outline in place a large dam was needed to store and distribute this water more effectively. The end result would be the creation of the Hoover Dam.

Colorado River Water Sharing Agreements

Before work could begin on the Hoover Dam, a water sharing agreement was needed between the states along the Colorado River basin. The demand for this essential water source in the dry, arid American Southwest was extremely high, and each state wanted to secure its fair share.

At the time prior rulings from the United States government and judicial authority stated that the Colorado River water should be distributed to the areas that needed it most for development. Essentially, this meant the states that were most populated and developed for agriculture would get priority for water rights.

Southern California was by far the most populous and developed among the seven states and was growing quickly. Thus, even though it contributed the least water runoff to the river, it could demand the most water at the expense of slower-growing states.

With this backdrop, the seven states met in 1922 to come to a formal agreement over water rights and allocations. Then-Secretary of Commerce Herbert Hoover presided over the negotiations.

Hoover Dam Colorado River Water Level Sharing Agreement chart

On November 24, 1922, six of the seven states signed what is now known as the Colorado River Compact (Arizona did not sign until 1944). The compact divided the Colorado River basin into two distinct areas: the Upper and Lower Basins.

Wyoming, Colorado, Utah, and New Mexico formed the Upper Basin while California, Arizona, and Nevada formed the Lower Basin. Each basin was apportioned 7.5 MAF (million acre feet) of water each year.

This total does not include the water rights of Native Americans that were guaranteed by the treaty. In addition, in 1944 the US and Mexico agreed to Mexico’s rights of 1.5 MAF annually.

The History of the Hoover Dam

The history of the Hoover Dam began as far back as 1922 with the signing of the Colorado River Compact. With the water allocations appropriately determined, planning of a massive dam to control flood waters and provide hydroelectric power could commence.

The early vision for the Hoover Dam was at a location called Boulder Canyon. After further review and geological studies, the site was ruled out for various reasons. The location for the massive dam was moved some 20 miles downstream to a more ideal site called Black Canyon. 

Some of the world’s best structural engineers came together to design an arch-gravity dam which was to become the largest dam in the world at the time.

In 1928 Congress approved $165M for the so-called “Boulder Canyon Project,” which consisted of the massive dam at Black Canyon and other dams and canals to harness the Colorado. It’s important to note that the name of the dam and project continued to be “Boulder” despite the construction site moving to Black Canyon.

Colorado River Basin agreement Hoover Dam
Map of the Colorado River Basin via

The dam was awarded to a joint venture called “Six Companies.” The name came from the fact that six separate engineering companies combined efforts to deliver the best quality bid for the project. At $49M, it was also the lowest of the bids received.

Before construction could commence there were some important roadblocks that needed to be tackled. Firstly, there needed to be a place to house the thousands or workers required for the project. As Black Canyon was in the middle of the desert, an entire city was built (Boulder City) to house the workers and their families.

In addition, railroad lines and highways were constructed to allow the fast transport of materials to the dam location. Power transmission lines were needed to supply energy for the construction as well.

Finally, in 1931 the Hoover Dam finally broke ground and began work. By 1936 the engineering marvel was completed, two years ahead of schedule.

Hoover Dam or Boulder Dam?

The modern day’s largest dam in the western hemisphere has not come without controversy.

Herbert Hoover was instrumental in allowing the Boulder Canyon project to flourish and gain traction. As Secretary of Commerce from 1921-1928, Hoover helped the relevant states negotiate the Colorado River Compact and publicly backed the project.

Hoover assumed the presidency in 1929, just after the project was approved through Congress. At that point it was still referred to as the “Boulder Dam” despite the construction site moving to Black Canyon.

In a September 1930 speech at the groundbreaking of the railroad from Las Vegas to the dam site, the new Secretary of the Interior Ray Wilbur declared that the Boulder Dam should now be called the Hoover Dam. It was a bold declaration that was politically charged.

The Black Canyon and future site of Hoover Dam – image via

The United States was in the middle of the Great Depression at the time, and many blamed Hoover for the crisis. Nevertheless, “Hoover Dam” was the title used in all official congressional documents.

When Hoover was voted out of office the incoming Roosevelt administration did everything in their power to remove Hoover’s association with the project. In 1933 Roosevelt’s Secretary of the Interior Harold Ickes announced that the Hoover Dam should revert back to being called the Boulder Dam.

It would remain as the Boulder Dam until 1947 when President Harry Truman would break with his party line and approved a congressional resolution to officially rename the completed dam the “Hoover Dam.”

The constant changing of the official name of the dam proved to be a nightmare for merchants in nearby Boulder City selling merchandise to the thousands of tourists.

Hoover Dam Water Level

In the creation of the Hoover Dam the engineers had to create one of the largest man-made lakes called Lake Mead. In recent years the water levels at the Hoover Dam and Lake Mead have fallen far below historical norms.

As of September 2022, the water levels were at about 1,045 feet. This is down from about 1,210 feet at the beginning of 2000.

The rapid fall in water levels is due to one of the longest droughts on record that is threatening to dry up the mighty Colorado. It also has threatened the Colorado River Compact as the river has failed to live up to original expectations in terms of water yields.

Lake Mead water level
Lake Mead at critically low levels via LOC

The original Colorado River Compact and subsequent Mexico agreement assumed the river would yield at least 16.5 MAF of water each year. This turned out to be an incredibly high estimate as recent years have yielded much lower amounts.

States have had to improve water conservation efforts to account for the lower inflows of water. In 2019 the seven states and Mexico agreed to several drought contingency plans around reduced water consumption should water levels at Lake Mead and other dams fall below critical thresholds.

At Lake Mead these thresholds include measures to be taken when or if water levels fall below certain levels. They further the water levels drop, the more drastic water conservation actions must be taken to maintain the supply from drying up.

It remains to be seen whether the seven states and Mexico can be savvy enough in their water conservation methods to maintain the water supply at Lake Mead and the Hoover Dam through the current severe droughts as a result of a changing climate.


To learn more about US history, check out this timeline of the history of the United States.

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