Welcome to Hoover Dam Tour

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Welcome to Hoover Dam

Tour stop audio transcript

Hoover Dam, once known as Boulder Dam, is a concrete arch-gravity dam in the Black Canyon of the Colorado River, on the border between the U.S. states of Nevada and Arizona. It was constructed between 1931 and 1936 during the Great Depression and was dedicated on September 30, 1935, by President Franklin D. Roosevelt. Its construction was the result of a massive effort involving thousands of workers, and cost over one hundred lives. The dam was controversially named after President Herbert Hoover. For more information visit http://www.usbr.gov/lc/hooverdam/

Penstock Towers

Tour stop audio transcript

Before water from Lake Mead reaches the turbines, it enters the intake towers and then four gradually narrowing penstocks which funnel the water down towards the powerhouse. The intakes provide a maximum hydraulic head (water pressure) of 590 ft (180 m) as the water reaches a speed of about 85 mph (140 km/h). The entire flow of the Colorado River passes through the turbines. The spillways and outlet works (jet-flow gates) are rarely used.[2] The jet-flow gates, located in concrete structures 180 feet (55 m) above the river, and also at the outlets of the inner diversion tunnels at river level, may be used to divert water around the dam in emergency or flood conditions, but have never done so, and in practice are only used to drain water from the penstocks for maintenance. Following an uprating project from 1986 to 1993, the total gross power rating for the plant, including two 2.4 megawatt Pelton turbine-generators that power Hoover Dam's own operations is a maximum capacity of 2080 megawatts. The annual generation of Hoover Dam varies. The maximum net generation was 10.348 TWh in 1984, and the minimum since 1940 was 2.648 TWh in 1956. The average has been about 4.2 TWh/year. To lower the minimum power pool elevation from 1,050 feet (320 m) to 950 feet (290 m), five wide-head turbines, designed to work efficiently with less flow, will be online by 2017.

Spillways

Dam Interior

Tour stop audio transcript

There are 17 main turbines in the Hoover Power plant -- nine on the Arizona wing and eight on the Nevada wing. The original turbines were replaced through an uprating program between 1986 and 1993. The plant has a nameplate capacity of about 2,080 megawatts. This includes the two station-service units (small generating units that provide power for plant operations), which are rated at 2.4 megawatts each. With the main units having a combined rated capacity of 2,991,000 horsepower, and two station-service units rated at 3,500 horsepower each, the plant has a rated capacity of 2,998,000 horsepower.

Visitor Center

Tour stop audio transcript

The complex, built of rose-colored concrete with tinted glass paneling, copper roofing and brass Art Deco railings, was intended to keep tourists off the crowded interstate highway that crosses the top of the dam. The visitor center gallery houses numerous audio, visual and interactive exhibits, including a full-scale model of the huge buckets used to move concrete for Hoover Dam construction, a walk-though model of generator, and a detailed diorama of the dam. Also featured are interactive exhibits that allow you to test your skill at managing power generation, conserving energy, and other skills.

Memorial Bridge

Tour stop audio transcript

The Mike O'Callaghan–Pat Tillman Memorial Bridge is an arch bridge in the United States that spans the Colorado River between the states of Arizona and Nevada. The bridge is located within the Lake Mead National Recreation Area approximately 30 miles (48 km) southeast of Las Vegas, and carries U.S. Route 93 over the Colorado River. Opened in 2010, it was the key component of the Hoover Dam Bypass project, which rerouted US 93 from its previous routing along the top of Hoover Dam and removed several hairpin turns and blind curves from the route. It is jointly named for Mike O'Callaghan, Governor of Nevada from 1971–1979, and Pat Tillman, an American football player who left his career with the Arizona Cardinals to enlist in the United States Army and was later killed in Afghanistan by friendly fire.

Oskar J.W. Hansen & Celestial Chart

Tour stop audio transcript

One of the highlights for many of the people who visit Hoover Dam each year is the artwork they find. While most people are impressed by these works, they often ask the question, "What do they mean?" Much of the sculpture is the work of Norwegian-born, naturalized American Oskar J.W. Hansen. Mr. Hansen fielded many questions about his work while it was being installed at the dam. In response to those questions, he later wrote about his interpretation of his sculptures. Hoover Dam, said Hansen, represented for him the building genius of America, "a monument to collective genius exerting itself in community efforts around a common need or ideal." He compared the dam to such works as the great pyramids of Egypt, and said that, when viewing these man-made structures, the viewer often asks of their builders, "What manner of men were these?"

Cafe and High Scaler

Tour stop audio transcript

This larger-than life sculpture of a man scaling a rock wall represents a "high scaler." In the 1930s, fearless, eager-to-please-in-a-down-economy dam workers would dangle hundreds of feet in the air, armed with jackhammers to jar loose rocks and dynamite to blast away at the canyon walls. Lots of men died in this occupation and others in creating the immense structure that turns Lake Mead into electricity. The bronze figure was created in the 1990s by sculptor Steven Liguori, in conjunction with a group of concessionaires who operate the businesses on government property around the landmark. The statue was based on a photo of one of the last of the high scalers then alive -- Joe Kine.

Lake Mead

Tour stop audio transcript

Lake Mead, when full, is the largest reservoir in the United States in terms of maximum water capacity. It is on the Colorado River about 24 mi (39 km) from the Las Vegas Strip southeast of the city of Las Vegas, Nevada, in the states of Nevada and Arizona. Formed by the Hoover Dam, Lake Mead is 112 miles (180 km) long when the lake is full, has 759 miles (1,221 km) of shoreline, is 532 feet (162 m) at greatest depth, with a surface elevation of 1,221.4 feet (372.3 m) above sea level, and has 247 square miles (640 km2) of surface, and when filled to available capacity, 26.12 million acre feet (32.22 km3) of water. However, the lake has not reached full capacity since 1983 due to a combination of drought and increased water demand. Owing to current low water level, Lake Sakakawea holds claim over Lake Mead in terms of America's largest reservoir by total area and water in reserve. The reservoir serves water to the states of Arizona, Nevada and California, providing sustenance to nearly 20 million people and large areas of farmland.

Boulder City

Tour stop audio transcript

The land upon which Boulder City was founded was a harsh, desert environment. Its sole reason for existence was the need to house workers contracted to build the Hoover Dam on the Colorado River (known commonly as Boulder Dam from 1933 to 1947, when it was officially renamed Hoover Dam by a joint resolution of Congress). Men hoping for work on the dam project had begun settling along the river in tents soon after the precise site for the dam had been chosen by the Bureau of Reclamation in 1930. Their ramshackle edifices were collectively known as "Ragtown". The sheer scale of the dam and duration of the project required the Bureau of Reclamation to consider the construction of a semi-permanent town rather than a temporary arrangement. Boulder City was exceptionally rare as an example of a town fully planned under government supervision.