8 Colossal Facts about Hoover Dam

Constructed nearly 90 years ago the magnificent Hoover Dam still stands strong and serves the Southwest with power production, flood control, and irrigation

The Hoover Dam can be called both a monument and a marvel reaching a staggering 60 stories toward the sky and at one time reigning as the world’s largest dam. This symbol of American engineering ingenuity—initially constructed to control the Colorado River’s floodwaters—attracts more than 7 million visitors each year to the Arizona-Nevada border to catch a glimpse of the dam’s massive curved wall and its waters below. Read on for six facts about the Hoover Dam from its original name to its dramatic World War II history.

Hoover Dam with shadow of Mike O’Callaghan-Pat Tillman Memorial Bridge © Rex Vogel, all rights reserved

1. Flood damage was a major reason for the Hoover Dam’s construction

The Colorado River helped carve out the American West and Southwest flowing for 1,450 miles and providing water to seven states: Colorado, New Mexico, Utah, Wyoming, Arizona, California, and Nevada. However, thanks to snowmelt from the Rocky Mountains the river was also prone to flooding. One such example of this flooding occurred between 1905 and 1907 when the Colorado River broke through its banks and flooded 100,000 acres of farmland in Southern California.

This was around the same time that the Bureau of Reclamation started planning for a dam in the Boulder Canyon region on the Colorado River. Plans were set in motion but flood control was not the only thing they had to think about. Water supply was another main reason for building the Hoover Dam.

Lastly, the Hoover Dam was built for power. Although this was not as vital as preventing flooding or providing irrigation it is a function of the dam that continues to this day.

Hoover Dam with shadow of Mike O’Callaghan-Pat Tillman Memorial Bridge © Rex Vogel, all rights reserved

2. Building the dam meant first building an entire city

Constructing a large-scale dam meant hiring a massive workforce: By the end of the project, the employee roster swelled to 21,000 people. An average day had 3,500 workers reporting to the construction site though that number rose during busy periods like in June 1934 when as many as 5,218 men reported to the jobsite per day. Bringing in that many workers and their families meant the federal government had to have a plan—which is how the town of Boulder City, Nevada came to exist.

In December 1928, President Calvin Coolidge authorized the creation of Boulder City on federal land specifically to house workers. Construction of the town’s buildings began in 1931. Families were housed in cottages while single men slept in dormitories and meals were provided in a jumbo-sized mess hall that served 6,000 meals per day. Boulder City was also equipped with a state-of-the-art hospital to handle jobsite accidents, a fire department, a train station, and a movie theater.

Hoover Dam with shadow of Mike O’Callaghan-Pat Tillman Memorial Bridge © Rex Vogel, all rights reserved

3. Constructing Hoover Dam required massive amounts of concrete

Building a structure as large as the Hoover Dam requires massive amounts of construction materials. The dam reaches 726 feet tall, a whopping 171 feet taller than the Washington Monument and the dam’s base is as thick as two football fields are long. Reaching those dimensions required engineers and builders to use a substantial amount of concrete—so much that the sheer volume (4.5 million cubic yards) could be used to pave a cross-country road starting in San Francisco and ending in New York City.

Ultimately, the dam had a $49 million price tag—about $882 million today—with an additional $71 million for its power plant and generators. However, the dam’s construction costs were fully repaid with interest by 1987 thanks to the sale of the electrical power it generated and continues to generate.

Hoover Dam with shadow of Mike O’Callaghan-Pat Tillman Memorial Bridge © Rex Vogel, all rights reserved

4. Hoover Dam originally had a different name

Hoover Dam gets its name from President Herbert Hoover though it nearly had a different one thanks to the influence of the Great Depression. Before becoming the 31st President in 1929, Hoover was a successful mining engineer and businessman familiar with the Colorado River; as secretary of commerce he had proposed damming the river to prevent flooding and to provide water for Southern California. Once underway, the dam which was overseen by Hoover during his presidency was called the Boulder Canyon Project. However, in September 1930, Secretary of the Interior Ray Lyman Wilbur announced at a ceremony marking the start of construction that the dam’s name would be changed to honor Hoover’s role in its development.

Construction continued through the Great Depression but Hoover’s presidency did not. President Franklin D. Roosevelt entered the Oval Office and in 1933 his pick for secretary of the interior decided to backtrack on the name due to personal animosity and public anger over Hoover’s handling of the Great Depression, once again calling it the Boulder Dam. Both names were used interchangeably until April 1947 when President Harry S. Truman approved the final name: Hoover Dam.

Hoover Dam with shadow of Mike O’Callaghan-Pat Tillman Memorial Bridge © Rex Vogel, all rights reserved

5. Hoover Dam was heavily guarded during World War II

In the lead-up to World War II, the federal government became increasingly worried that the Hoover Dam would be a target of sabotage from Axis forces knocking out its ability to provide electricity and water. In 1939, public officials discussed shielding the dam by closing its power plant to the public while also heavily restricting and scrutinizing employees who entered.

In November of that year, the State Department received word from the U.S. Embassy in Mexico that German agents had plotted to bomb the dam hoping to knock out its high-voltage power lines and slow aviation manufacturing in nearby Los Angeles. A massive effort to protect the dam was soon underway including the addition of floodlights, installation of nets that could snag approaching boats, and increased patrols on Lake Mead which was closed to the public. However, the government’s move to protect the dam remained classified with public officials claiming rumors of foreign sabotage were “ridiculous” and unfounded. The incident was kept under wraps until 2001 when historians uncovered unsealed documents at the National Archives.

Lake Mead © Rex Vogel, all rights reserved

6. Lake Mead is the country’s largest reservoir

Dams rely on reservoirs (man-made lakes) that store water. As Hoover Dam is one of the largest dams in the world it makes sense that its reservoir would be massive and it is; Lake Mead is the largest reservoir in the U.S. and one of the largest in the world. The expansive lake is multipurpose; it provides drinking water for nearly 25 million people and its 550 miles of shoreline have been used by outdoor enthusiasts since it became the country’s first national recreation area managed by the National Park Service in 1964.

Mike O’Callaghan-Pat Tillman Memorial Bridge © Rex Vogel, all rights reserved

7. Hoover Dam can be admired from the bridge

While there are more than enough things to see and enjoy at Hoover Dam, visitors can also marvel at and even walk across the Mike O’Callaghan-Pat Tillman Memorial Bridge. As the world’s tallest concrete arch bridge, it is the first concrete-steel arch composite bridge in the United States and towers 880 feet over Hoover Dam.

The 1,905-foot-long man made bridge connects both Nevada and Arizona roadways so it’s fitting that it’s named the Mike O’Callaghan-Pat Tillman Memorial Bridge as it honors a hero from each state. With 30,000 cubic yards of concrete and 16 million pounds of steel, the massive engineered wonder is the widest of its kind in the Western Hemisphere. Visitors who aren’t afraid of heights can even walk across the bridge for some great photo opportunities of Hoover Dam and Black Canyon below.

Hoover Dam as seen from Mike O’Callaghan-Pat Tillman Memorial Bridge © Rex Vogel, all rights reserved

8. Visitors can tour Hoover Dam

A Hoover Dam tour is a fun and interactive way to see and learn what Hoover Dam is all about. Tours are guided and allow visitors to explore lesser-known parts of the dam and lasts longer than the Powerplant Tour.

The Hoover Dam Tour includes a one-hour guided tour of the powerplant and passageways within the dam itself while the Powerplant Tour is a 30-minute tour of the powerplant only. Both tours include admission to the Visitor Center.

Hoover Dam tours cost $30 per person. Hoover Dam Powerplant Tours cost $15 for adults, $12 for seniors and those ages 4 to 16. Military members pay $12 for admission or free if in uniform. Children under 4 are also admitted for free. Parking costs $10.

If you’re short on time or budget, skip the Hoover Dam tour and walk across the Top of the Dam for free. Visitors will enjoy sweeping vistas of the bridge and surrounding geographic features along with vertigo-inducing views looking straight down the dam.

Worth Pondering…

This is our history—from the Transcontinental Railroad to the Hoover Dam, to the dredging of our ports and building of our most historic bridges—our American ancestors prioritized growth and investment in our nation’s infrastructure.

—Cory Booker