Hoover Dam: Facts And Figures
All hail the engineering accomplishment that is Hoover Dam! This giant concrete structure, which provides electricity and drinking water throughout the Southwest, is still a testament to man’s ability to construct colossal projects in the middle of nowhere. Today, Hoover Dam is a National Historic Landmark and it’s still listed as one of America’s Seven Modern Civil Engineering Wonders. Here’s some more history that is sure to make you utter, “What a dam wonder!”

By The Numbers
· Hoover Dam is 726.4 feet tall—that’s from the bottom of its foundation up to its crest. The towers on the walls at its crest rise another 40 feet. When Hoover Dam was built, it was the tallest dam in the world and today it remains “the tallest concrete arch dam in the U.S.”
· Hoover Dam is 1,244 feet long across its crest and 660 feet long across its base.
· To build Hoover Dam, more than 5.5 million cubic yards of earth had to be dug up to make way for diversion tunnels for the Colorado River, its foundation, a power plant, cofferdams and spillways.
· Hoover Dam is estimated to weigh more than 6.6 million tons.
· Hoover Dam is made of concrete—more than 3.25 million cubic yards of it! This amount of concrete could pave a standard highway that’s 16 feet wide all the way from San Francisco to New York City.
· Speaking of concrete, more than 5 million barrels of cement mix were required to build Hoover Dam. Interestingly, up until then, the Bureau of Reclamation had only used 5.86 million barrels in its 27-year construction history.
· Hoover Dam was built in blocks. They ranged in length/width from 25 feet square at its downstream face to 60 feet square at its upstream face. The concrete that was poured into each block (i.e., its depth) was limited to five feet —as that took 72 hours to cool.
· In order to cool the concrete (which in normal circumstances would have taken 100 years), engineers dissipated the heat by imbedding 582 miles of steel pipe through the blocks and circulating ice water. They’d built an ammonia refrigeration plant in order to chill the water—one that was so powerful it was capable of producing a 1,000-pound ice block daily.
· Along with concrete, the U.S. government had a big shopping list to fill for Hoover Dam. The materials it needed included 45 million pounds of reinforcement steel, 21.67 million pounds of gates and valves, 88 million pounds of plate steel and outlet pipes, 840 miles of other pipes and fittings, 18 million pounds of structural steel and 5.3 million pounds of miscellaneous metal.
· There were 21,000 men employed in the construction of Hoover Dam. An average of 3,500 men were on site daily. The average monthly payroll was $500,000.
· Before construction could begin on Hoover Dam, a city had to be built to house all the employees and government officials. That’s Boulder City! It is situated eight miles west of the dam site.
· Additional pre-construction work for Hoover Dam included building a 22-foot-wide highway from Boulder City to the dam site and laying 32.7 miles of railroad tracks from the main line of the Union Pacific in Las Vegas to Boulder City and the dam site. A 222-mile-long power transmission line from San Bernardino, Calif., also had to be put in place to supply energy for everything.
· It cost $49 million to build Hoover Dam—that’s a relatively low figure in today’s world!
· Hoover Dam has a power capacity of 1,345 megawatts, which comes from 17 hydroelectric generating units. It supplies electricity to the states of Arizona, California and Nevada.
· Hoover Dam created Lake Mead, the largest reservoir in the U.S. with a surface area of 247 square miles. The dam can store up to 9.2 trillion gallons of water from the Colorado River (nearly two years of its flow), if necessary.
· The maximum water pressure at the base of Hoover Dam is 45,000 pounds per square foot.
· Each year, about 20,000 cars and trucks drive across Hoover Dam between Nevada and Arizona.
· Over 100,000 people visit Hoover Dam Tour annually. They either drive (it’s about 45 minutes from the Las Vegas Strip) or take one of best helicopter tours provide by Maverick Helicopters to see this amazing wonder from above.

By The History
· In 1928 the seven states through which the Colorado River runs signed the Boulder Canyon Project Act to define how much water each state could rightfully claim. This agreement paved the way for Hoover Dam to be built—along with the Imperial Dam (near Yuma, Ariz.) and the All-American Canal.
· Hoover Dam was originally to be built in Boulder Canyon, which is located 10 miles away from its current location. The site was moved after an engineering reassessment determined the dam could capture more water in Black Canyon.
· Hoover Dam was built during the Great Depression. Men hoping for employment began drifting in to Las Vegas from all around the country as early as 1929, well before construction began. They even brought their wives and children. Since these families had nothing and work was not immediately available, their living conditions were impoverished and most settled in an infamous shantytown called Ragtown, which was located on the floor of Black Canyon next to the Colorado River.
· When it came time to submit construction bids to build Hoover Dam, six firms formed a group called Six Company, Inc. to put together a competitive proposal. They became the lowest bidder at $48,890,955 and were awarded the contract. During construction, Six Company was offered bonuses and received threats of fines for each day they overran the construction schedule. In they end, they finished two years ahead of that schedule!
· One of the most dangerous jobs at Hoover Dam was that of the high scaler. Men with this position had to climb down Black Canyon’s walls by rope and set blasts to remove weakened rocks from the cliffs, where the ends of Hoover Dam would join. High scalers were paid more for their bravery—they made 75¢ per hour versus 50¢ per hour, which was what the other construction positions paid.
· The first concrete for Hoover Dam was poured on June 6, 1933, and the last concrete was poured on May 29, 1935. An average of 160,000 cubic yards of concrete were poured per month.
· The contractors and engineers were originally allowed seven years beginning on April 20, 1931 to build Hoover Dam, along with the power plant and related structures. When the concrete placement was completed early, this led to all the construction being completed by March 1, 1936—in just under five years.
· On September 30, 1935, President Franklin Delano Roosevelt came and gave the dedication speech in which he called Hoover Dam “a great feat of mankind.”
· Hoover Dam has undergone a couple of name changes over the years. In 1931, a congressional act was passed that followed the tradition of naming dams for sitting presidents. Thus, it was originally called Hoover Dam after President Herbert Hoover. However, when President Roosevelt took office in 1932, his interior secretary announced that it should instead be known as Boulder Dam. In 1947, the name was changed back to Hoover Dam to honor President Hoover, who had always been an avid supporter of the project.
· Currently, Hoover Dam serves as a crossing for U.S. Highway 93, but this will change in 2010 when the Mike O'Callaghan-Pat Tillman Memorial Bridge is completed as part of the larger Hoover Dam Bypass Project. The new bridge will be located just downstream of the dam. It will be the first concrete-steel composite arch bridge built in the U.S., and visitors will be able to park and walk across it for spectacular views of Hoover Dam.
With Maverick Helicopter tours you have a wonderful view of the famous
Hoover Dam as you fly over on your Grand Canyon adventure.