Hoover Dam. USA
Hoover Dam (or Hoover Dam)-one of the highest dams on the planet, and one of the most powerful hydroelectric power plants in America.
It is located in the southwestern part of the country right on the Nevada-Arizona border, on the Colorado River where the border runs.
Hoover Dam on the map
- geographic coordinates 36.016065, -114.737411
- the distance from the U.s. capital Washington D.C. is about 3350 kilometers straight line
- to the nearest airport Boulder City about 14 km
- The nearest McCarran International Airport in the famous Las Vegas is 40 km to the west
- Hoover Dam is located at the outlet of Lake Mead, the largest man-made reservoir in the United States
The construction of the dam was necessary based on several factors. The Colorado River, with its erratic nature, periodically flooded large areas of agricultural land downstream. Building a dam had the potential to calm the violent temper of the river and stabilize its water level. In addition, it could serve as an impetus to the development of irrigated agriculture in the region.
The enormous reservoir created by the construction of the dam would be able to meet the water needs of virtually all of southern California. Finally, the dam’s hydroelectric plant, will serve to benefit the people living in the surrounding area.
Hoover Dam in numbers
- Height – 221.4 meters
- Length – 379 meters
- Height above sea level – 376 meters
- Width at the base – 200 meters
- Width at the top 14 meters
- Volume of the dam – 2 480 000 m 3
- Weighing more than 6,600,000 tons
- Spillway capacity – 11 000 cubic meters per second
- Type – arched-gravity, semi-circular in shape directed toward Lake Mead, which allows for more efficient distribution of water load. The water pressure at the bottom of the dam is about 220 tons per square meter
Such a grandiose construction required a lot of research and approvals. As early as the beginning of the 20th century (in 1902) there were searches for opportunities to build a small dam on the Colorado River. But little success was achieved.
Then, in 1922, it was decided to create a commission, which included representatives of all states interested in the equitable distribution of water resources on the river and the construction of the dam. The commission included Herbert Hoover (he was not president yet, but represented the federal government). On November 22, 1922, the commission signed the Colorado River Convention, which spelled out the relationship between the entities claiming the resources of the river.
But construction of the dam did not begin immediately. It was not until late 1928 that John Calvin Coolidge (the 30th President of the USA) signed a bill authorizing the construction. But the first financial contributions to the project came only in July 1930, when the 31st President of the United States was Herbert Hoover himself.
The process of building the Hoover Dam
According to the plan, construction was to begin in 1931 and be completed in 1938. However, the massive project was already commissioned in 1936 two years earlier.
At the time, such a structure was a challenge to the most advanced technology. The environmental conditions, with temperatures often reaching 50 o C, the need to change the Colorado River channel during construction, and a host of other inconveniences posed serious challenges to engineers and designers.
For example, it was not possible to simply pour concrete into a large formwork, as at ambient temperature the entire structure would cure for about 125 years! In addition, the process of “setting” and “hardening” of the concrete in such a large volume would inevitably lead to cracking and destruction.
Naturally, the developers were not satisfied with the concrete setting time or its output quality. A unique engineering solution was adopted – to assemble the entire gigantic reinforced concrete structure from separate blocks.
This solution, by the way, we already know from the structures in the ancient city of Sacsayhuaman in Peru. But, if in Sacsayhuaman the technology of fitting huge blocks is still unknown to science, in the Hoover Dam it is not a secret.
Roughly speaking, the whole dam was assembled almost like a children’s Lego set.
All the blocks were the same height, about one and a half meters. But the other dimensions varied depending on where the block was placed. The maximum size of the block was 18 m 2 (at the bottom of the dam) and the minimum was 7.6 m 2 (at the top). Within these blocks were 1-inch (about 2.5 cm) diameter steel pipes through which the ice water circulated. This allowed the concrete to set properly.
The result was a very high quality concrete block reinforced by pipes that also connected the blocks to each other. By the way, the total length of such pipes was 937 km! After the block had hardened, the pipes were filled with concrete and the next block was casted. Thus a single monolithic structure was created. In 1995, studies were conducted that proved that the concrete of the Hoover Dam was still gaining strength. And such a parameter as compressive strength is generally out of the standard range for commonly used concrete.
As you can imagine, the construction of such an enormous project required considerable manpower. And in the beginning there was almost nothing provided for their accommodation. The workers lived in the territory of temporary camps and in rather difficult conditions. As a result, on August 8, 1931, the builders went on strike, which was forcibly suppressed. It was not until the spring of 1932 that worker housing was rebuilt in the Boulder City township and the unrest ceased.
Throughout the construction, gambling and the sale of alcohol were prohibited in the city. Boulder City is the only city in Nevada where gambling is still banned.
To change the course of the river and take water away from the work site, four tunnels (two on each side of the river) with a diameter of just over 17 meters each and a total length of about five kilometers were drilled into the mountains. The walls of the tunnels were poured with concrete 90 cm thick. Therefore, the effective diameter was reduced to 15 meters. At the end of the construction of the dam, these tunnels were not encased. So they are still in operation, which in turn gives the dam stability and reduces the load.
The energy of the water found its use in the hydroelectric power plant. On October 26, 1936, the power plant gave the first electricity. Today, the total capacity of the 17 generators is 2080 MW.
If you open all the spillways of the dam, the energy of the falling water is about 25,000,000 horsepower.
Tragedies at Hoover Dam
Unfortunately, throughout the surveying, research, and construction work, fatalities were not uncommon. A total of 112 people died during the work, according to official records.
The sad statistic was discovered on December 20, 1922 by surveyor JG Tierney (original JG Tierney). He drowned while searching for a dam site in Black Canyon, where the Colorado River flowed.
Then there were accidents and several suicides. But there is something else interesting. Officially, the last death recorded during construction is dated December 20, 1935, which is exactly 13 years after the first tragedy. But that’s not all. The last dead man’s name was Patrick Tierney. He was the son of the same surveyor who tore off the deadly account.
There is a memorial in honor of all those who died in the construction of the dam, with an inscription that reads, “They died so that the deserts might bloom.”
Despite the tragedies and difficulties associated with the construction of the dam, the facility was completed ahead of schedule and in compliance with all technical regulations.
It is noteworthy that from 1933 until 1947 the dam was called “Boulder Dam” because it was originally planned to be built in Boulder Canyon. The name was retained even when construction of the dam began in Black Canyon.
During the groundbreaking ceremony, it was suggested that the project be named “Hoover Dam” in honor of the then president. There is indeed a tradition in the U.S. of naming a major dam after the president in office at the time of its construction. And in February 1931 Congress officially approved the name.
The adventures with the name did not stop there. In 1932, Franklin Roosevelt was elected president. His administration decided to rename the dam back to Boulder Dam. Although no official decision was made, Hoover’s name disappeared from all documents, both official and from tourist brochures.
In 1947, two years after Roosevelt’s death, a bill was introduced in the Senate to return the name of Herbert Hoover to the dam. It was approved by the Senate and signed by the president. And now the whole world knows this landmark of the United States as the “Hoover Dam”.
The upper part of the dam is a bridge that connects the banks of the Colorado River. After the tragedy of September 11, 2001 access across the dam was restricted, and in 2010 a redundant bridge was built half a kilometer away from the dam, which significantly reduced the load on the dam and increased its safety. Such a colossal structure invariably attracts tourists, so you can take a tour here and learn a lot of interesting things.
The dark secrets of the Hoover Dam or the massive construction of the Great Depression
My apologies to all subscribers, but I have not been able to begin another travel series that includes wintertime trips to the Hoover Dam, the Grand Canyon, and Sedona. Why winter? Probably because most travelers choose the spring-summer time when the temperature often reaches +40C or more, plus the crowds don’t allow you to enjoy the beauty in peace and quiet And the photos of the Canyon with snow on the slopes are quite unusual, in contrast to the red-hot rock in the summertime.
So let’s start at the beginning – a trip to the Hoover Dam – one of the largest and most famous hydraulic structure in the U.S., the object of interest of numerous tourists from around the world, the subject of numerous science fiction movies and so on.
The road to the dam is an hour southeast of the “city of all sins,” Las Vegas, and as the steep walls rise, it slowly prepares tourists for the view. To get there in time for the main influx of tourists, I left town at about 8 a.m., so the roads were practically empty and offered great views of the surrounding mountains and an orphaned hotel attached to them.
Not far from the dam, which by the way was still hidden by the canyon slopes, the road diverges into two: one leading to the dam itself, the other to the O’Callaghan-Tillman Bridge, built only by 2010, to unload the highway, which previously ran through the dam itself and was a real “bottle-neck”. Also one of the reasons was the compulsory inspection of cars before entering the dam in order to avoid the transportation of explosives, which further reduced the capacity.
The bridge itself is a good half-kilometer long, with one side in the state of Nevada and the other in Arizona. In fact, you can travel through time on it on foot or by car, since these states are located in different time zones. If you decide to walk on it, be prepared for the strongest winds – take care of your shirts, hats, panama hats, and goggles.
It took five years to build (plus two years of preparation for the main construction phase and slope clearance), required 60,000 tons of concrete and 8,000 tons of steel, and is now the first composite arch-and-iron bridge and the second tallest in the States.
Two lanes of traffic in each direction (instead of the two oncoming lanes on the causeway) and no “stop-and-go” corners ensure good capacity.
It is from the bridge that you have a wonderful view of the dam and, blended into the surrounding slopes, the main museum building, parking lot, and other associated structure. At the base of the dam you can see the generator station buildings, emergency spillways, and various technical tunnels for access and maintenance.
In front of the museum building is a cast-in-metal figure of the bridge builder. In the earliest part of construction, they rappelled down from 250 meters, clearing the slopes, clearing loose rocks and subsequent blasting to reach the hard rock of the canyon walls. To at least protect themselves from the frequent rock falls, the workers invented to dip their hats in tar, soak them in the sun to dry, and repeat the process several times until they were stiff enough. This is how the prototype of the standard construction helmet was invented, which is now a mandatory piece of equipment in any construction job.
At the time of the beginning of construction in the country was raging Great Depression, so the hourly wage of 50 cents to $ 1.25 attracted many – people began to flock to the site of the future dam in search of work, the first year living in tents, until a small town was built near Boulder City with adequate infrastructure. The site itself employed just over 3,500 people a day (5,000 at peak) and just over 21,000 in all at the site itself, although the project did employ many factories and steel mills in neighboring states. And a lot of farmers afterward.
Interestingly, workers were strictly selected on the basis of race, as outlined in the contract between the government and the contractor, the “Big Six” companies, and this was an echo of the politics of the day: the vast majority were white, war veterans, blacks and Mexicans not exceeding a small quota and employed in the hardest and most unskilled jobs. And a special order prohibited the employment of Chinese and any Asians, apparently the government estimated the scale of their settlement when building and rebuilding San Francisco after the 1906 fire, when the local Chinese diaspora became one of the largest in the United States.
The building itself is best viewed while walking along the dam. According to the guide – at first they wanted to make all the buildings just as concrete buildings, not different in color from the dam itself, but then they decided that it was not appropriate for such a large and famous dam to be a gray mouse, so they invited an architect who perfectly blended the buildings into the surrounding rocks and worked on the style of the upper part of the dam. The result was an entire ensemble in the then popular Art Deco style. As it turned out – they did not go wrong, as evidenced by the flow of tourists.
If you have time not only to walk/drive around the dam, but also to visit the museum and the tour – I highly recommend it, for $30 (plus $10 for parking) it’s worth it. They show you a short film from the 30’s about the construction of the dam, walk you through the museum, the generator room, the grim corridors in the body of the dam itself and the surrounding cliffs.
After going through airport-like security, which I had to go through twice (I forgot to leave my Benchmade 581 in the car a hard childhood in the 90’s ) and watching a movie before the tour, the tour guide and I went down to the level of the bypass water lines in the body of the dam. After cramming the whole group into the elevator, the elephant counted us by our heads, reported this figure to the post and we went down a couple of hundred meters, and then through a corridor cut through the rocks we went to the first point of our tour – the bypass pipeline, which serves to deliver water to the turbines and the emergency discharge of water when the reservoir is full. It had been used twice for dumping: in 1941 for the test and in 1983 when the reservoir was overfilled.
15 meters in diameter and connected by 3-inch rivets, they extend out to either side of the observation hall. Unlike many other dams, where they are in the body of the dam, these spillways “bypass” the dam so as not to disturb its strength, because in fact, it transmits all the water pressure to the walls of the gorge… it does not need extra holes
There are a lot of hypotheses, ranging from building the dam on the “bones of the workers” to a hidden secret laboratory in the bowels of the dam from “Transformers”. Official statistics state that the first recorded death was the fall from the cliff of geologist J. G. Tierney, who was looking for a place for the dam (he crashed and drowned), and 111 more people after him, with the list closed by his son Patrick, who died 13 years after his father… that’s the family curse. If confirmations to the first it is possible to find in many official sources, so about the second (secret laboratory) our guide has convinced us. The truth he murmured in a whisper that perhaps he had no appropriate clearance and he was certainly not a young blonde with the appearance of a model.
Next, we are led into the generator room on the Nevada side. How do you tell? Easy: there are 17 generators on the dam, 8 on the Nevada side and 9 on the Arizona side, which are located in a room about 120 meters long and as high as 90. Or you can tell by the windows in the room itself where the sun is looking in. Almost like we learned at school: where the moss grows – that side is north.
The view from the tourist bridge is spectacular: The rows of Francis-type vertical hydraulic turbines were installed between 1936 and 1961, so they are not identical. All together they produce just over 2 Gigawatts. There were only 3 turbines operating in the wing at the time of this photo, which can be identified visually by the orange light burning on the hood, plus through the armored inspection window to see the rotor spinning inside.
As the tour guide said: the main reason, after all, was not the generation of power, but the collection of floodwaters and the agro-technical importance of the dam itself, where the water is divided among the three states, as legislated in a special document. Although in terms of percentage the energy is also shared: the city itself at the dam gets 1.8% + the rest of Nevada 23.5%, Arizona 19%, and the rest goes to California respectively.
When one of the Japanese tourists, careful to pronounce the words, asked the tour guide how long he thought the construction would take in modern times (the original project started in 1928, construction itself went from 1931 to 1935 and the launch occurred in 1936), he thought for a few seconds, grinned and ranted: “From 15 to 25 years. Given that all the calculations and construction could be squeezed into 3-4 years. Looking up at the surprised eyes of the person who asked, he said, verbatim: “And how many years do you think all the approvals would have taken for a construction of this type, which affects the eco-systems of several states? And what money would have been spent on countless commissions and approvals, and on paying lawyers? Yes the “greenies” and the likes of Greenpeace would be racking their brains about preserving unique species in the area, flooding the land nearby, and the like? People and the government used to be more pragmatic: it is necessary to preserve water for irrigated agriculture – so it is necessary, generation of additional electricity – we will build it, creation of jobs now and in the future – only for it. If for this some turtle or a bird will have to leave its burrow and move ten kilometers – so it is so, on the other hand, hunger and unemployment of tens of thousands of fellow citizens are in the balance.
We were also led in a roundabout way to one of the technical vents which emerges midway up the dam. The view of the other generator wing, the slopes of the Black Canyon, and the tamed Colorado River through the protective louvers is not bad either, but it’s more for the “I’ve been here” ticker.
The corridors in the dam itself are tiled from floor to ceiling even at the time of construction, it’s interesting to realize that it was done many years before your parents were born, nothing particularly chipped / crumbled… and still drives fans of tiling everything to ecstasy
But the technical tunnels that run from the base of the dam to the emergency exits upstairs – tile spared, they do not take tourists there anyway But there is a drain for condensation, and most importantly – the gate, which in the case of a fall on the stairs will not let the fractured and breathless carcass to the bottom, and stop alive in a dozen meters.
It is said that young and hot station workers try to climb it “from and through” for a while as an argument. “To the madness of the brave we sing the glory,” as the old Rahim used to say.
As an appetizer, we were (once again counted by our heads) taken up to the dam itself and let out into the fresh air. On any given day of the week, there are hundreds of tourists strolling around the dam, rolling convertibles, couples and singles snapping selfies and all around.
There are even some protruding pockets at the very edge of the dam for a better view of the dam and the suicides . Sadly, from the time the dam was built until the opening of the O’Callaghan-Tillman Bridge in 2010 – about 35 people jumped off it, but then decided the bridge was still more reliable: much higher and farther to fly. Pardon the black humor, but it doesn’t compare to the popularity of the Golden Gate Bridge, where the “death toll” is estimated at 1600+ officially registered deaths. Every country has its own infamous sites.
After passing the causeway, you can take the serpentine up a few turns to the gift store, which offers a view of the causeway itself. For comparison, I’m attaching a historic photo from the Library of Congress that shows the base of the dam not yet submerged. Unfortunately it was pretty overcast, so it was a little gloomy, but it was probably better than taking the pictures in the searing summer midday sun.
After that I drove over the causeway into Nevada and back to Vegas, looking at the traffic jam for miles around with tourists who were just waking up from a busy afternoon and partying, and praising themselves for getting up and driving in the morning.
For those who were able to read to the end and want to see archival photos of the dam construction – you can visit this page on an interesting resource TEOTI.