Hoover Dam. The Hoover Dam in the USA: the history of construction, description, photo

The Hoover Dam is a hydroelectric structure and a hydroelectric power plant in the United States. It is built in the lower reaches of the Colorado River. The height of the dam is 221 m. It is in the Black Canyon, near the states of Nevada and Arizona. It was named in honor of the country's 31st president, Herbert Hoover, who played an important role in its construction. The construction of the dam occurred in 1931-1936.

The Hoover Dam is under the control of the US Department of the Interior Bureau of Land Reclamation. It is one of the most famous attractions of Las Vegas.

Prehistory

Before the erection of the dam, Colorado (the river) often showed its violent temper. During the melting of snow in the mountains, it often flooded the farmland of farmers that were downstream. Designers believed that dam construction would help smooth fluctuations in river levels. In addition, it was expected that this reservoir will push the development of irrigated agriculture and become a source of water supply in many areas of Southern California.

One of the main obstacles to the implementation of this project were the doubts of representatives of states that were in the Colorado basin. The river, or rather its water resources, should have been fairly distributed among consumers. There were thoughts that California, with all its influence and finances, would lay claim to the bulk of the water reserves of this reservoir.

Because of this, a commission was established, which included one representative from each state concerned, as well as a representative from the federal government. The result of its activities was the signed Convention of the Colorado River. In it, ways of allocating water resources were fixed. This opened the way to the erection of the dam.

Construction of a hydraulic structure of this scale required the attraction of substantial funds from the state budget. The bill on financing was approved by the White House and the US Senate not at once. In 1928, Calvin Coolidge signed a bill, giving the go-ahead for the implementation of this project. The first allocations for the construction were made only after 2 years. The then president was Herbert Hoover.

The plan provided for the construction of a dam in Boulder (Canyon of the Colorado River). And although it was finally decided to build it in the Black Canyon, this project became known as the Boulder Canyon Project.

Building

For the construction of dams in a row was entrusted to several companies. Among them: Six Companies, Inc., Morrison-Knudsen Company; Utah Construction Company; Pacific Bridge Company; Henry J. Kaiser & WA Bechtel Company; MacDonald & Kahn Ltd., JF Shea Company.

Workers

Thousands of workers took part in the construction (in 1934 the maximum number was 5251 people). Under the terms of the contract, the hiring of Chinese workers was not permitted, and the total number of black mercenaries did not exceed 30, while they were employed in the most underpaid work. It was assumed that near the dam for the builders will be built a small town, but the schedule was redesigned in favor of increasing the number of jobs and speeding up the process (to reduce unemployment, which was the result of the Great Depression). Because of this, by the time the first mercenaries arrived, the city was not yet ready, and the dam builders spent the first summer in the camps.

Dangerous working conditions and delayed delivery of housing led to a strike, which took place in 1931. At the same time, the workers were dispersed with the use of force (the police used batons and weapons). However, the pace of construction of the town was decided to accelerate, and in the spring of the following year people moved to already permanent dwellings. For the period of construction in Boulder City, gambling, prostitution, and the sale of alcoholic beverages were prohibited. The last ban here remained until 1969. Gambling same business is not allowed to this day, which makes Boulder City the only city in the state of Nevada, which operates a similar ban.

Working conditions

Hoover Dam, the photo of which is presented in this article, was built under difficult conditions. Some of the work was carried out in tunnels, where workers suffered from carbon monoxide, which here was in abundance (some builders therefore died or became disabled). The employer then stated that deaths were a consequence of the transferred pneumonia, and he was not responsible. At the same time, the construction of this dam was the first construction site on which workers were given protective helmets.

During the erection of the dam (dam), a total of 96 people died. The very first of these was the topographer J. Tierney, who drowned at the end of 1922 in Colorado, choosing the best place for construction. Ironically, the last victim of the dam was Patrick Tierney, his son, who died 30 years later, falling from the spillway tower.

Preliminary work

The construction of the dam dam was scheduled on the border between Arizona and Nevada in a narrow canyon. To divert water away from the point of construction, 4 tunnels were created. It is worth noting that their total length was 4.9 km. In 1931 the construction of the tunnels began. Their finish was made of concrete, the thickness of which was 0.9 m, due to which the useful diameter of the water lines reached 15.2 m.

Tunnels after the completion of the construction were partially blocked by "plugs" of concrete and in some places used to discharge excess water. The fact that the spillway does not occur through the body of the dam itself, but through tunnels that are located in the rocks, gives stability to the entire structure.

Erection of dam-caissons

To prevent possible flooding, as well as insulation of the construction site, two caisson dams were built. The upper dam began to be erected in 1932, although at that time the outlying tunnels were not completed.

To ensure the safety of work before the construction began, various measures were taken to clean the walls of the canyon from rocks and freely lying stones: they were first undermined by dynamite, and then dropped off.

Construction of a concrete dam

At the base of the dam, the first concrete was poured in 1933. For its production, the nearest deposits of nonmetallic materials were discovered. In addition, specially for this purpose, concrete plants were built.

Since works of this magnitude have never been produced before (it should be noted here that no dams in the world could match the scope of this construction), several technical solutions used in the process were truly unique. For example, one of the problems was the cooling of concrete. Due to this, instead of a continuous monolith, the Hoover Dam was built as a series of interconnected columns in the form of trapezoids. This allowed the excessive heat that was released during the solidification of the mixture to dissipate.

Engineers realized that if the Hoover Dam was to be built as a monolith, then 125 years would be required to cool the concrete to the required temperature. Due to this, cracks could appear, and in the future it would entail the destruction of the dam. In addition, each form to accelerate the cooling of the concrete layers contained a cooling system of metal inch pipes, where the cooled river water came in. It must be said that the curing of concrete is still incomplete today.

Power station

The creation of a pit for a hydroelectric power station was carried out together with the digging of the pit, which was intended for the foundation of the dam. The necessary excavation work was completed in 1933, in the same year, the first concrete was poured into the building of the power plant.

The first electricity generators of the station were produced in 1936. After 25 years, during the modernization of this station, other additional generators were launched. At the present moment, seventeen generators are produced here, with a maximum capacity of 2,074 MW.

The role of the power station today

The power plant plays a very important role in maintaining a balance of energy consumption in the western United States. The power consumption depends on the adjustment of the load to each of the generators, which is regulated by a distribution station located in Phoenix. Interestingly, prior to 1991, a system with manual control was used; In the future computerization of this system was carried out.

Architecture

The original project assumed a very simple architectural solution for the building of a hydroelectric power station and a dam. It was assumed that the dam on the outside would be an ordinary wall, framed on top by a balustrade, created in the Gothic style. While the building of the power plant did not have to be different from a simple factory workshop.

By many contemporaries, the proposed project was criticized for its excessive simplicity, which, in their opinion, did not correspond to the epoch-making nature of the Hoover Dam. As a result, the Los Angeles architect Gordon Kaufman was invited to rework the project. He managed to rework the project, having executed the exterior of these structures in the Art Deco style. As a result, the upper part of the dam was decorated with turrets, which "grew up" directly from the dam. In addition, he placed the watch on the spillway towers. Some of them demonstrate Mountain Time, and the second - Pacific North American time.

The name of the dam

Originally, the Hoover Dam had to be erected in the Boulder Canyon, hence, in official documents it was called the "Boulder Dam". At the official opening of this construction, Ray Wilbur, US Secretary of the Interior announced that the structure will be named after US President Hoover. With this statement, Wilbur continued the tradition of assigning the names of presidents to the largest dams in the United States. The US Congress approved this official name in 1931.

A year later, Hoover lost the election to Franklin Delano Roosevelt, a candidate from the Democrats. After Roosevelt took office, the US administration suggested changing the dam's name to the "Boulder Dam". On this occasion, the official decision was not taken, but of all the tourist guides and official documents of those years, the name of Hoover disappeared.

Two years after the death of Roosevelt, Jack Anderson, a California congressman, introduced a project to return the building to the name of Hoover. The corresponding bill was signed by the president, and from that moment the dam is named "Hoover Dam".

Transport value

On the dam until 2010, there was a highway 93, which ran in the meridional direction and connected the Mexican border with the state of Arizona. The part of the highway that was adjacent to the dam, the volume of the transport and the highway that passed was inconsistent. The road has in each direction only one strip, and its descending serpentine to the dam includes several narrow and steep turns, places with very poor visibility. In addition, the road is prone to frequent landslides.

It should be noted that after the 2001 terrorist attack, traffic was restricted through this dam. Some types of cars before passage are subject to mandatory inspection to prevent the transport of explosives, the rest are inspected only periodically.

In 2010, near the Hoover Dam, Mike O'Callaghan's bridge was opened. It significantly increased the capacity of this highway.

Influence on nature

The formation of the Mead reservoir and the construction of this dam had a significant impact on the Colorado River, its water regime, and especially on its ecosystem. Many dams are so damaging. During the 6 years of construction of the dam and the filling of the reservoir, the delta water practically did not reach.

The construction stopped frequent floods, which differed the canyon of the Colorado River. But this posed a direct threat to a number of species of plants and animals that have already adapted to regular flooding. The erection of the dam downstream reduced the fish population. At the present moment, 4 species of fish are threatened with complete extinction.

Even today, on the terrain near the Mead reservoir, you can see a trace from the upper water level, which was reached in 1983. This was due to the unusually large amount of precipitation that fell as a result of the El Niño effect in the western United States.

The image of this dam was used in various works of art. For example, the dam was mentioned in the book "One-storied America" by Ilf and Petrov, in the films "Universal Soldier" and "Transformers", as well as in the animated film "Beavis and Butthead."