50 Fun Facts About Hoover Dam

Hoover Dam was built in which gorge of the Colorado River?

The site was originally expected to be Boulder Canyon, 20 miles upstream, and the project kept the 'Boulder Canyon Project' name even after engineers moved it.

The dam straddles the border between Nevada and which other state?

The state line runs across the crest, and each side has its own clock face on the intake towers.

The dam is roughly 30 miles southeast of which major city?

The city lobbied hard to be the construction headquarters and even shut its speakeasies when the Interior Secretary visited, but lost out to a purpose-built town.

Which president formally dedicated the dam on September 30, 1935?

The ceremony was moved up three hours the morning of the event because a reserved radio slot turned out to be 2 p.m. Eastern, not Pacific.

What was the dam's official name between 1933 and 1947?

The three-cent stamp issued for the 1935 dedication carried the alternative name rather than the one used today.

How tall is the dam from foundation rock to the roadway on its crest?

The towers and ornaments on the parapet add another 40 feet above the crest.

What structural type of dam is Hoover?

It is thick at the bottom and thin at the top, with a convex face that pushes the water's force into the canyon walls.

Roughly how many tourists visit the dam each year?

Nearly a million of them take the paid Bureau of Reclamation tours; the rest see it from the crest and the visitor center.

In the 2007 film Transformers, what does the dam secretly house?

The Decepticons attack the dam during the film to retrieve their frozen leader.

In which 2015 disaster film does a massive earthquake collapse the dam?

The 1978 Superman film also destroyed it on screen, that time after a nuclear bomb triggered the San Andreas Fault.

Which Griswold family comedy features Clark springing a leak inside the dam's walkways?

The 1997 film had the family visit the dam on a side trip from the Strip.

Which town was built specifically to house the dam's construction workers?

Gambling has been banned there since it was founded, making it one of only two places in Nevada where you cannot legally gamble.

Lake Mead holds which US record?

At full pool it stretches 112 miles, reaches 532 feet deep, and holds over 28 million acre-feet of water.

Which consortium won the contract to build the dam in 1931?

Its bid of $48,890,955 came within $24,000 of the government's confidential estimate.

Who was the general construction superintendent who ran the job for the contractor?

He earned two patents for the giant concrete buckets used on the job and went on to build Shasta Dam in California.

What were the workers called who dangled from ropes to blast loose rock off the canyon walls?

They became a tourist attraction in their own right, and one was nicknamed the 'Human Pendulum' for swinging co-workers across the canyon.

Which piece of safety gear did workers improvise at the dam by dipping cloth caps in tar?

Men struck hard enough to break their jaws walked away without skull injuries, so the contractor ordered thousands of them.

Had the dam been poured as one continuous mass, how long did engineers calculate the concrete would take to cool?

Instead it was poured as interlocking blocks threaded with cooling pipes carrying ice water from an on-site refrigeration plant.

How much 1-inch steel cooling pipe was embedded in the concrete?

The refrigeration plant that chilled the water could produce 1,000 tons of ice a day.

According to the Bureau of Reclamation, how many workers are buried inside the dam's concrete?

Each bucket raised the level in a form by only about an inch, and crews of 'puddlers' worked every pour, so a body could not have gone unnoticed.

What is the Bureau of Reclamation's official count of construction fatalities?

Broader tallies reach 112 by counting a 1922 surveying drowning and other deaths outside the site.

Which Interior Secretary ordered in 1933 that the dam stop carrying Hoover's name?

At the 1935 dedication he pointedly used the rival name five times in thirty seconds, and he still opposed the later restoration as a private citizen.

In what year did Congress unanimously restore the name Hoover Dam?

By then many Americans used both names interchangeably and mapmakers were split over which to print.

Which president signed the 1928 act that authorized the dam?

The act appropriated $165 million and also covered the downstream Imperial Dam and All-American Canal.

Which architect gave the dam its streamlined Art Deco look after the first plans were called too plain?

The Bureau's original design had a Gothic-inspired balustrade and eagle statues before he was brought in.

What are the two 30-foot bronze statues at the dedication plaza called?

Each was cast in a single continuous pour and then slid into place on blocks of ice to protect the polished bronze.

What does the terrazzo star map at the base of the plaza's flagpole monument record?

It was laid out so precisely that future astronomers could work out the exact date even if written records were lost.

Where did the four-lane Hoover Dam Bypass bridge, opened in October 2010, cross the river?

Through traffic across the crest ended when it opened; visitors can still drive over to the parking lots on the far side.

The bypass bridge is co-named for which NFL player killed in Afghanistan in 2004?

The other honoree, Mike O'Callaghan, was Nevada's governor from 1971 to 1979.

Lake Mead is named for Elwood Mead, who held what job?

He held the post from 1924 to 1936, spanning the planning and construction of the entire Boulder Canyon Project.

What causes the white 'bathtub ring' visible around Lake Mead when the water is low?

The lake has not been full since 1983, and hit its lowest level since first filling in the summer of 2022.

Why do the clock faces on the two intake towers agree for more than half the year?

The two states are in different time zones, so the clocks disagree only in winter.

Before he was president, Hoover chaired the 1922 negotiations that produced which water agreement?

He was Secretary of Commerce at the time; the compact divided the river among seven basin states and was signed on November 24, 1922.

Which honor did the dam receive in 1985?

It had already made the National Register of Historic Places in 1981 and been named a National Historic Civil Engineering Landmark in 1984.

How many main turbine-generators does the powerplant have?

The original plan called for 16 large units, but two smaller ones replaced a single big one on one side of the river.

On what date was the first concrete poured into the dam?

That was 18 months ahead of schedule; the last of it went in on May 29, 1935.

What was the maximum daily workforce recorded on the dam?

About 21,000 men worked on the project overall, with an average of 3,500 on any given day.

What was the nickname of the squatters' camp on the riverbank where families waited for dam jobs?

Its official name was Williamsville; the summer of 1931 there averaged nearly 120 degrees and killed 16 people from heat.

Which company built the first Francis turbine-generators that went online at the dam in 1936?

The final generator was not placed in service until 1961.

How many times have the dam's huge spillway tunnels actually carried water?

Both uses, a 1941 test and the 1983 floods, left cavitation damage in the tunnel linings that had to be repaired.

What did the Bureau of Reclamation secretly spend nine years doing after Lake Mead began to leak?

The original grouting had left 58 of 393 holes incompletely filled because crews were rushing to beat the concrete pour.

Which submerged Nevada town, drowned by Lake Mead in 1938, has resurfaced as the water level fell?

Its ruins are reachable by dirt road and hiking trail thanks to the lake's low water.

Which sculptor created the dam's dedication plaza, its bas-reliefs and its memorial plaque?

Norwegian-born, he wanted the work to express 'the enormous power of trained physical strength'.

Which Interior Secretary first named it Hoover Dam at the 1930 railway ceremony?

He cited a tradition of naming dams after presidents, though none had ever been honored while still in office.

Which Denver artist designed the Native American-inspired floor and wall motifs inside the dam?

He also devised the color-coding for pipes and machinery that was adopted across all Bureau of Reclamation projects.

Whose fall from an intake tower in 1935 closed the fatality list, exactly 13 years after his father died at the site?

His father, surveyor J.G. Tierney, drowned in a flash flood on December 20, 1922, one of the very first names on the list.

Which lower Colorado dam suffered concrete deterioration from alkali-silica reaction that Hoover avoided?

Cores taken in 1995 showed Hoover's concrete was still slowly gaining strength six decades on.

How many diversion tunnels were driven through the canyon walls to move the river aside?

Two ran on the Nevada side and two on the Arizona side, each 56 feet across and totalling more than three miles in length.

When the dam was handed to the federal government in March 1936, how far ahead of schedule was it?

That was despite brutal summer heat and untested techniques, since nothing on that scale in concrete had been built before.

How much concrete went into the dam itself before pouring stopped in May 1935?

Another 1,110,000 cubic yards went into the power plant and other works, and each bucket only deepened a form by about an inch.