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.
Today we translate them into a great national possession. Today marks the official completion and dedication of Boulder Dam. This is an engineering victory of the first order—another great achievement of American resourcefulness, American skill and determination. That is why I have the right once more to congratulate you who have built Boulder Dam and on behalf of the Nation to say to you, "Well done. During the s, the big dam on the Colorado was usually called the "Boulder Canyon Project" or sometimes "Boulder Dam.
Why do you think he used the old name in his speech? In , Congress unanimously changed the name back to "Hoover Dam. What three groups did Roosevelt credit with the building of the dam? Which group's contributions do you think he valued the most? What makes you think so? Do you agree, based on what you know so far? The President identified benefits the new dam had already provided. What were they? Whom did they benefit?
Roosevelt strongly defended the work relief projects for which his administration was famous. What arguments did he use? Do you think he made a good case? If you were reading or listening to Roosevelt's speech in , would you think that Hoover Dam was one of his New Deal work relief projects?
Was it? This image shows three views of the dam. The left side shows what a visitor looking upstream at the dam would actually see.
The cut-away view on the right side shows features that would not be visible from the surface. Although not shown in the illustration, all of the features shown in the cut-away are duplicated on the other side of the dam. The cross section in the upper right hand corner is a side view. Look carefully at the cut-away view. Can you trace the course the water follows from the reservoir through the power plants and outlet works and then back into the river?
How does that change if the level of the reservoir is getting too high? How many of the features mentioned in Reading 2 can you find in this image? Is the image or the reading more useful in helping you understand Hoover Dam? Reclamation engineers prepared hundreds of drawings for the construction company—all much more detailed than this simplified illustration.
Why do you think the detailed drawings were necessary? How do you think the engineers decided where to locate the features shown here? Look at the drawing in the upper right hand corner. Why do you think the dam had to be so thick at the bottom? Find the penstocks that carry the water from the intake towers to the horseshoe-shaped powerhouse at the foot of the dam. One of the definitions of "penstock" is a pipe or conduit that carries water from a reservoir to electrical generating equipment.
The Boulder Canyon Project Act said that the cost of building Hoover Dam had to be repaid by selling electricity and that contracts for all the electricity had to be signed before construction began.
Why do you think that was required? When the contracts were signed, almost two thirds of the electricity went to Southern California. Why do you think that might have been the case? Boulder City Museum and Historical Association; photographer unknown. How many men can you count in Photo 1? Why do you think so many people came to this remote and hostile location looking for work? What were conditions like in America in ?
Refer to your textbook if necessary. Describe the setting in these images. The average high temperature in this area in August is degrees. Summer temperatures in the canyon can easily reach degrees. The area is also prone to cloudbursts, high winds, and sudden floods. What do you think working here would be like? Do you think you would have come here looking for a job? Many of the men seeking work brought their families with them.
Why do you think they did that? Work on the dam began sooner than originally planned. Housing for workers in the new town of Boulder City wasn't ready when these photos were taken. Families created a temporary community called "Ragtown. Describe the shelter shown in Photo 2. Do you think this would have been adequate?
The shelter seems to be located next to the river. Do you think that would have been a safe place to live? Reread Lesson No. In addition to drilling holes for dynamite, the scalers also knocked unstable rock loose by hand. Why was this work necessary? What safety equipment can you find in this picture?
How much protection do you think it offered against rock falling down from above? Look at the upper right hand corner of the image. This shows the floor of the canyon, hundreds of feet below.
Do you think the safety equipment would have kept the men from falling? How many high scalers can you find in this photo? Other historic photos show dense rows of men working close together on the canyon walls. How safe do you think this would have been? Many newspapers and magazines featured descriptions and images of the "high scalers. Do you think you would have wanted to do work like this? The jumbos backed up to the working faces in the tunnels so that men using all the drills could work at the same time and higher on the wall without the need for scaffolds.
The men filled the holes they had drilled with dynamite and then the jumbos drove away. After the dynamite was detonated, the rock dislodged by the explosion was taken out of the tunnel.
Eventually they removed 1. Look carefully at this image. Look for the drills they look a little like machine guns. How many of them can you count? Why do you think Six Companies developed this process? How do you think they might have done this work without the jumbos? Why do you think Six Companies was so anxious to get this part of the project done quickly? Refer to Reading 2 if necessary. Internal combustion engines produce carbon monoxide.
State laws prohibited using them in enclosed spaces like tunnels for health and safety reasons, but Six Companies used the jumbos anyway. What kind of danger does carbon monoxide present? Why do you think Six Companies disregarded the state law? What other hazards do you think the men working on the jumbos might have faced?
How large is 1 cubic yard? Measure your classroom and figure out how many cubic yards it could hold. How many of your classrooms would it take to hold 1. What do you think is going on in this image? Where is the river? Look at Illustration 1. Does that help you figure out where the river went? How many steam shovels can you count?
Based on the size of the people in the image, how big do you think these shovels were? The shovels had to remove about feet of soil and loose rock before they could get down to solid rock. Why do you think it was so important to do that before starting work on the dam structure itself?
By , the date of this photo, Six Companies had built a lookout on the top of the canyon for tourists coming to the site. Why do you think visitors would drive so far to watch the dam under construction? Why do you think the construction company was willing to spend the money to build the lookout? By studying "The Greatest Dam in the World": Building Hoover Dam, students have learned why Hoover Dam was a triumph for the engineers of the Bureau of Reclamation, for the construction company that built it, and for the thousands of men who worked to complete it.
Their demands included ice water, flush toilets, and that the Six Companies follow mining laws since they were blasting through bedrock and digging diversion tunnels at the time.
Despite all these challenges, employment at the dam was a sought-after gig. Some men and their families moved up towards Nevada in hoping to reserve employment. The dam was built right in the middle of the Great Depression so the idea of long-term employment — no matter how dangerous — was appealing.
Entire families lived in makeshift homes and quickly-build towns in the middle of nowhere. Boulder City, Nevada was constructed to house all the contractors working the job and their families. Despite what the stories say, no bodies were buried within the concrete of the dam.
Officially, 96 people died during construction. Struck by, drowning, falling debris, blasting and other construction-related deaths are included in this number. The Hoover Dam is an iconic piece of American history and its landscape.
The name of the Hoover Dam changed a few times during its first few decades. There are miles of cooling pipe in the am to control the temperature of the concrete and prevalent cracks.
Over 2,, square meters of concrete were used to build the dam — enough concrete to build a two-lane highway from San Francisco to New York City. Today, the future of the Hoover Dam remains bright. As water shortages and droughts threaten the production of the dam, using the dam as a type of super-battery could help keep the dam relevant as times change.
The Hoover Dam was a game-changing construction project that still stands as a beacon of innovation and infrastructure design.
Equipment Rentals. How It's Built. Building the Hoover Dam. Why Was the Hoover Dam Built? Planning the Dam Plans for the dam took over 30 years of research, lobbying, organization and design. Construction of the Hoover Dam After surveying and choosing Black Canyon as the spot to build the dam, explosives were used to blast away the sides of the canyon for construction. DirtStories is all about the people and companies who build the construction industry.
Get in touch with the personal side of construction. In the early 20th century, the U. Bureau of Reclamation devised plans for a massive dam on the Arizona-Nevada border to tame the Colorado River and provide water and hydroelectric power for the developing Southwest. Construction within the strict timeframe proved an immense challenge, as the crew bored into carbon monoxide-choked tunnels and dangled from heights of feet to clear canyon walls.
The largest dam in the world at the time of its completion in , this National Historic Landmark stores enough water in Lake Mead to irrigate 2 million acres and serves as a popular tourist destination. At the turn of the 20th century, farmers sought to divert the Colorado River to budding Southwestern communities via a series of canals.
When the Colorado broke through the canals in , creating the inland Salton Sea, the job of controlling the raging river fell to the U. Bureau of Reclamation. Bureau director Arthur Powell Davis in outlined a plan before Congress for a multipurpose dam in Black Canyon, located on the Arizona- Nevada border. Named the Boulder Canyon project, after the original proposed site, the dam would not only control flooding and irrigation, it would generate and sell hydroelectric power to recoup its costs.
Secretary of Commerce Herbert Hoover brokered the Colorado River Compact to divide the water proportionally among the seven states, but the legal wrangling continued until outgoing President Calvin Coolidge authorized the Boulder Canyon Project in December As the Great Depression unfolded, hopeful laborers descended on Las Vegas and set up camp in the surrounding desert for the chance to work on the project.
Those who were hired eventually moved to Boulder City, a community specifically built six miles from the work site to house its employees. Meanwhile, the U. The first difficult step of construction involved blasting the canyon walls to create four diversion tunnels for the water. Facing strict time deadlines, workers toiled in degree tunnels choked with carbon monoxide and dust, conditions that prompted a six-day strike in August The second step of involved the clearing of the walls that would contain the dam.
Suspended from heights of up to feet above the canyon floor, high scalers wielded pound jackhammers and metal poles to knock loose material, a treacherous task that resulted in casualties from falling workers, equipment and rocks. Meanwhile, the dried riverbed allowed for construction to begin on the powerplant, four intake towers and the dam itself.
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