Most of the water is used in the Lower Colorado Basin. If you had to decide how much of the river's water each state could have, what factors might you consider? If the states did not agree with what you recommended, who do you think should have the right to make a final decision? The river crosses the border into Mexico. How would you decide how much water Mexico could claim?
Who could make that decision? How many dams can you find on the Colorado River? Hoover Dam was the first of those on the map. Why do you think there are so many now? Before the building of Hoover Dam, the Colorado River was dangerous and unreliable. Melting snow in the mountains caused damaging floods during the late spring and early summer.
Unpredictable flash floods could occur in any season. In , the Colorado River flooded rich, irrigated farmland in the Imperial Valley in southern California.
It caused enormous damage and permanently flooded thousands of acres. Reclamation engineers began to study the Colorado River soon after passage of the Reclamation Act in They were looking for places to build dams to store the water from the annual spring runoff, releasing it gradually during the summer for irrigation.
By the early s, most people thought that building a big dam on the lower Colorado was the best way to store water to irrigate the low-lying valleys of Arizona and southern California and to protect them from floods. By this time, too, developers in Los Angeles and other rapidly growing cities in Southern California had added their powerful support for the project.
They saw the dam as a potential source of water and hydroelectric power for homes, businesses, and factories. In , the seven states of the Colorado River Basin met to decide how to divide the waters of the river. Herbert Hoover, at that time the secretary of commerce for Republican President Calvin Coolidge, led the discussions. Most of the states were afraid California was going to get more than its fair share of the water.
Ultimately, they managed to agree on a document, called the Colorado River Compact. The compact also committed the U. Some states were not happy about the compact; Arizona did not ratify it until It did permit planning for the dam to proceed, however. Also in , congressional representatives from California introduced a bill to authorize Reclamation to build the big dam on the lower Colorado. By this time, they were among the most knowledgeable and experienced dam builders in the world, but even they had never done anything this big.
Hoover Dam would be the highest dam in the world, far taller than anything they had built so far. The lake it created would be the largest in the world. The proposed dam would be so tall and the pressure of the water it held back so great that many people were worried. Others wondered whether the expected benefits would be enough to justify the enormous cost.
Despite these questions, planning and design went forward. Six Companies was a group of some of the largest construction companies in the country. They joined specifically for this project. The contract divided the work between Six Companies and Reclamation. Reclamation engineers designed the dam and created the hundreds of detailed plans and specifications that the contractors would follow. If the work was consistent with the plans, they approved it for payment.
They hired and housed the workers. They transported supplies to the dam site. They were responsible for keeping the project on schedule and within budget. The plan was for construction to start in the fall of , in the depths of the Great Depression, which had begun with the stock market crash of Herbert Hoover, now president, wanted to start work on the dam earlier, probably as a way to ease high unemployment.
Work actually began during the summer and continued around the clock until the dam was completed in , two years ahead of schedule. By this time, Franklin D. Roosevelt, a Democrat, had been elected president. The huge dam on the Colorado captured the imagination of journalists, authors, and filmmakers.
The New Deal was famous for using public works projects to put Americans back to work. In the early 21st century, almost a million visitors a year still come to see the great dam on the Colorado River. Hoover Dam is 1, feet long at the top. It is feet high from the lowest point of the foundation to the crest.
The dam is feet thick at the base and tapers to 45 feet thick at the top. Its reservoir was the largest artificial lake in the world for decades and is still the largest in the United States. Questions for Reading 1 1. Why did many people think something needed to be done to control the Colorado River?
What sort of problems did the river create? What benefits would controlling it provide and to whom? Why were congressional representatives from the state of California the leading supporters of a big dam on the Colorado? Why do you think President Coolidge's secretary of commerce led the discussions leading up to the Colorado River Compact?
What role might the federal government be able to play in making decisions like this? An acre-foot is the volume of water that would cover one acre one foot deep. Why do you think they used a measure like that, rather than something like gallons? How many gallons of water are in an acre-foot?
How much would that weigh? What were some of the concerns people had about its construction? How did Reclamation and Six Companies divide the work on the dam? Department of the Interior, ; and Donald C. The guide included the instructions excerpted below: 15 Minute Course in Engineering Full? In fact there are still quite a few nice canyons along the Colorado River. You can take one of them—no one will miss it—maybe. And you will need to build some roads and erect a power line.
At Boulder Dam they had to get the electricity from Los Angeles to build the dam which now sends electricity back to Los Angeles. Sand and gravel—get quite a bit of this to mix with the cement; enough to make 4,, cubic yards of concrete. Pipe for ice water— miles of it will do. Plate steel for making pipes—88 million pounds—when you get into pipe 30 feet in diameter, you have to make your own. Structural steel, nuts, bolts—and other stuff like that—18 million pounds.
Assorted steam shovels, etc. Make them each 56 feet in diameter, then line them with three feet of concrete. When you finish you will have 3 miles of tunnel 50 feet in diameter. At the other end of the tunnels build another cofferdam to keep the water from backing up, pump the puddles out from between, and there you have it—a dry spot in the river, with the stream running right around it, through the tunnels.
Lower several hundred men from the top on ropes and let them drill the cliffs full of holes. Stuff the holes with dynamite, and blast it away. Repeat as necessary. Better do that right now. Build a platform so spectators can watch, and dig down about feet from the river bed to bed rock, removing all loose material as you go. You are now ready to install the main portion of the dam. Concrete has a nasty habit of cracking. The lime in cement causes it to get hot when it is mixed with water.
Obviously you must not allow this to happen when you are building a dam. If cracks were to appear in your dam it might cause severe criticism from people living below the dam—or from their heirs. It would take years for all that concrete in the dam to cool under normal conditions. To hurry it up, string two or three miles of water pipe around through each five-foot layer of concrete as you pour it.
From your ice plant, run ice cold brine through the pipes. This will cause the mass to cool and shrink quickly. Your dam will be sealed tighter than a drum—and wedged between the canyon walls.
Drill holes connecting them with two of the tunnels constructed in Lesson 4. Plug the upper end of the tunnels to cut off water from the lake. At flood time, if the lake rises high enough to reach the spillways, it can be turned out through these original tunnels.
Erect a power house below the dam. Now drill holes through the cliffs from towers to power plant. Connect them with pipes. As you make each section of pipe, X-ray it for defects. This completes our engineering course. Questions for Reading 2 1. This guide contains many large numbers. Can you think of ways to translate those numbers into comparisons with more familiar things, so that it would be easier to get a sense of how big the project was? The diversion tunnels were among the longest in the world when they were built.
Six Companies thought that building them was the most critical part of the project. Why do you think both Reclamation and Six Companies thought the diversion tunnels were so important? Do you agree?
Explain your answer. Why was it important to speed up the cooling process? How long would it take for the concrete in the dam to cool by itself?
The pipes are still there, buried in the concrete. The spillways at Hoover Dam are only used when the water in the reservoir is so high that it would otherwise overflow the top of the dam. Why do you think the engineers thought they had to keep this from happening? In Lesson 1, the guide suggests, possibly not quite seriously, that you could take any canyon on the Colorado you wanted—"no one will miss it, maybe.
What might people "miss" about these canyons if they were filled with water? Do you think anybody today would suggest that no one might notice if you flooded one of them? Why or why not? Augustin, , pages Used by permission. In addition to the 10, people who braved o heat to hear the speech in person, it was broadcast to a radio audience of millions of people. This morning I came, I saw and I was conquered, as everyone would be who sees for the first time this great feat of mankind.
We are here to celebrate the completion of the greatest dam in the world, rising feet above the bedrock of the river and altering the geography of a whole region; we are here to see the creation of the largest artificial lake in the world— miles long, holding enough water, for example, to cover the State of Connecticut to a depth of ten feet; and we are here to see nearing completion a power house which will contain the largest generators yet installed in this country.
All these dimensions are superlative. They represent and embody the accumulated engineering knowledge and experience of centuries; and when we behold them it is fitting that we pay tribute to the genius of their designers. We recognize also the energy, resourcefulness and zeal of the builders, who, under the greatest physical obstacles, have pushed this work forward to completion two years in advance of the contract requirements.
But especially, we express our gratitude to the thousands of workers who gave brain and brawn to this great work of construction. We know that, as an unregulated river, the Colorado added little of value to the region this dam serves. When in flood the river was a threatening torrent. In the dry months of the year it shrank to a trickling stream.
The gates of these great diversion tunnels were closed here at Boulder Dam last February. In June a great flood came down the river. It came roaring down the canyons of the Colorado, through Grand Canyon, Iceberg and Boulder Canyons, but it was caught and safely held behind Boulder Dam. Across the desert and mountains to the west and south run great electric transmission lines by which factory motors, street and household lights and irrigation pumps will be operated in Southern Arizona and California.
The price of Boulder Dam during the depression years provided [work] for 4, men, most of them heads of families, and many thousands more were enabled to earn a livelihood through manufacture of materials and machinery. And this picture is true on different scales in regard to the thousands of projects undertaken by the Federal Government, by the States and by the counties and municipalities in recent years.
Throughout our national history we have had a great program of public improvements, and in these past two years all that we have done has been to accelerate that program. We know, too, that the reason for this speeding up was the need of giving relief to several million men and women whose earning capacity had been destroyed by the complexities and lack of thought of the economic system of the past generation.
In a little over two years this great national work has accomplished much. We have helped mankind by the works themselves and, at the same time, we have created the necessary purchasing power to throw in the clutch to start the wheels of what we call private industry.
Such expenditures on all of these works, great and small, flow out to many beneficiaries; they revive other and more remote industries and businesses. Labor makes wealth. The use of materials makes wealth. To employ workers and materials when private employment has failed is to translate into great national possessions the energy that otherwise would be wasted.
Boulder Dam is a splendid symbol of that principle. The mighty waters of the Colorado were running unused to the sea. Topping out at feet above the Canyon floor and stretching 1, feet across Black Canyon, the Hoover Dam was the tallest dam in the world when it opened in the s. It took 6. Without this cooling system, the Dam would still be cooling and solidifying today.
The equivalent of about , gallons of water. Take a Lake Mead Cruise and see it for yourself. Fantastic photo opportunities are almost as abundant as concrete at the Hoover Dam. Here are some of the most popular:. Work started in April That summer, Southern Nevada sweltered through record-breaking temperatures for months. By June, just two short months into construction, the average daily temperature was reaching a high of degrees Fahrenheit. The workers in the deepest parts of the tunnels worked in temperatures between to degrees Fahrenheit during the summer months!
Understandably, many of the workers suffered heatstroke on multiple occasions. Las Vegas, also known today as Sin City, wanted to be the place where the Hoover Dam project established its headquarters. In , Las Vegas was not the glittering metropolis we know today, but it still had a reputation for being a wild west party town that could pose a debaucherous distraction for those employed to build the dam. When the U. He shut down several brothels and speakeasies in an effort to lend the city an air of class.
Today, the dam is a thriving tourist destination on top of being a functioning power plant. It offers stunning views and fascinating insight, and each year nearly 7 million people visit the dam to snap selfies and experience its grandeur.
And the best part? Hoover Dam is just a short ride from the glitz and glamour of Las Vegas. Contact Gray Line today to learn more about our Hoover Dam tours. Gray Line Las Vegas uses cookies to improve your site experience. Learn more. Close Search in Top Menu What are you looking for?
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