Before
Hoover Dam
After
By- Balaji.T.K, CE02B011
CONTENTS
No Description Page no
1. Hoover dam –an Introduction 1
2. Requirements posed by structural design 2
3. Requirements posed by other details 6
4. Type of Concrete 7
5. Guidelines for Mix design 9
6. Fabrication and Installation 10
7. Formwork 11
8. Cooling of concrete 12
9. Temperature control of Mass Concrete 12
10. Quality Assurance 13
11. Bibliography 14
Hoover Dam- an Introduction!
It still stands tall as an engineering marvel high above the Colorado River between Arizona and Nevada. Hoover Dam attracts over 7 million visitors from around the new world every year feeding vast tourism into the Las Vegas Nevada and Arizona economy.
The building of Hoover Dam took the brilliance of over 200 engineers to pull-off what many deemed as almost impossible. And it was the fortitude of over 7,000 dam workers that endured amazingly harsh conditions and extreme dangers to complete Hoover Dam almost two years ahead of schedule
The Mission of the Dam:
1. Flooding along the Colorado River as it made its way to the Gulf of California had to be controlled.
2. The water-flow had to be harnessed to provide much needed water to the fertile, yet arid agricultural areas of California and Arizona.
3. Hydroelectric energy was to satisfy the requirements of millions and millions of people in adjacent regions.
Some Statistics About the dimensions of the dam:
Hoover Dam is 726 feet tall and 1,244 feet long. At its base, Hoover Dam is 660 feet thick which is 60 feet longer than two football fields laid end-to-end. Combined with its top thickness of 45 feet, there is enough concrete (4.5 million cubic yards) in Hoover Dam to build a two-lane highway from Seattle Washington to Miami Florida. Or imagine a four-foot wide sidewalk around Earth at its equator.
A scenic by-product of Hoover Dam is the gigantic reservoir of Lake Mead, a stunningly beautiful water recreation wonderland. This boating, sailing, fishing and house-boating paradise attracts over 10 million visitors a year. Lake Mead covers 550 miles of majestic shoreline and 247 square miles of area which is twice the size of Rhode Island. Its capacity of 1 1/4 trillion cubic feet of water would cover the entire state of Pennsylvania one foot deep.
Requirements for concrete posed by Structural design:
The Hoover Dam is an arch dam. Arch dams transmit most of the horizontal thrust of the water stored behind them to the abutments by arch action and hence thinner cross sections are sufficient (compared to the massive cross-sections of the gravity dams). Narrow V-shaped canyons(just like the Black canyon where the Hoover dam was constructed) will be suited for locating arch dams since they can withstand the thrust produced by the arch section.
John Adams Dam was built on another Genesee River tributary to form a recreational pond affecting 43.78 miles of river (Fish, n.d.). There is a small, unnamed barrier affecting 3.16 miles of Genesee River tributary in the center of the park. I assume that it had been used during the building of walkways or roads in the park; however, there is no documentation on the dam’s purpose.
Wuerthner, George. North Idaho's Lake Country. Helena, MT: American & World Geographic Pub., 1995. Print.
In December 1936 the United States Department of the Interior authorized the Lower Colorado River Authority to construct a low dam at the site of an old crossing on the river known as Marshall Ford. Marshall Ford Dam was completed in 1941 through the collaboration of the United States Bureau of Reclamation (USBR) and the Lower Colorado River Authority (LCRA) of Texas. The original purpose of the dam was to prevent floods from devastating Austin, TX. The capital city had substandard heavy damage from previous floods since its establishment in 1846. Soon bureaucrats came together to create the Colorado River Project, wanting to create a series of dams along the Colorado River to create hydroelectric power and serve to control floods and droughts. With Buchanan dam well under way with a total of six planned Marshall Ford was the only dam designed primarily for flood control and the only dam in which USBR oversaw construction. With money scarce there was debate over the final height dam and it reservoir capacity. This issue resolves itself with the flood of 1938. Once completed Marshall Ford Dam would flood 65 miles of the Colorado to form Lake Travis, creating the largest of the seven reservoirs known as the Highland Lakes.
The Bureau of Reclamation’s article, “Hoover Dam: What is Biggest?” (2012), announced the largest dam is 984 feet tall while the largest hydropower dam produces 90 billion kilo-watts of energy per year (¶ 3-4).
The one feature common to the Hoover Dam, The Mississippi river and the three gorges dam is that they all tried to control nature’s swings, specifically in the form of flooding. Before the Hoover dam was built, the Colorado river “used to flood spectacularly…but after 1900 the Colorado provoked a vehement response” (Pg 177). The response was simple, but large. The U.S. built several large dams, including the Hoover dam, on the Colorado to decrease its flooding and increase power and irrigation. Unfortunately, just as human control of the Colorado’s flooding increased, its organisms and habitats were detrimentally influenced, and the water became more and more salinated.
The negative aspects of Glen Canyon Dam greatly exceed the positive aspects. The dam’s hydroelectric power supply is only three percent of the total power used by the six states that are served by the facility. There is a surplus of power on the Colorado Plateau and with more and more power-plants being created in the western hemisphere, Glen Canyon Dam’s power is not needed (Living Rivers: What about the hydroelectric loss). Although the ‘lake’ contains twenty seven million acre feet of water, one and a half million acre feet of water are lost yearly due to evaporation and seepage into the sandstone banks surrounding the ‘lake’ (Living Rivers: What about the water supply?). The loss of that much “water represents millions, even billions of dollars” (Farmer 183). If the government were to employ more water efficient irrigation practices, as much as five million acre feet of water per year could be saved.
The South Fork Dam collapsed and unleashed 20 million tons of water from its reservoir. A wall of water, reaching up to 70 feet high, swept 14 miles down the Little Conemaugh River Valley, carrying away steel mills, houses, livestock and people. At 4:07 p.m., the floodwaters rushed into the industrial city of Johnstown, crushing houses and downtown businesses in a whirlpool that lasted 10 minutes. (New York Times, 1889).
20 dams have been built, many of them by the U.S. Bureau of Reclamation, along the River and the tributaries. The Hoover Dam, which holds back at the Black Canyon to form the reservoir Lake Mead, one of the largest artificial lakes in the world. The Glen Canyon D... ... middle of paper ... ... nts for profit along the river's course can hardly complain when a river flows where it's supposed to go.
Over the years Glen Canyon Dam has been the spark for hundreds of debates, rallies, and protests. These debates have been going on for almost forty years now. The fact is that the dam created a huge lake when it was built, this is what bothers environmentalists. This lake is called Lake Powell and thousands of people depend on its tourists for income. The lake also filled up a canyon called Glen Canyon, some people say it was the most beautiful place on earth. The anti-dam side of the debate has its basis in the fact that Lake Powell is currently covering Glen Canyon. It was very remote so few people got to witness its splendor. This is probably the reason the dam was built in the first place, ignorance.
As the empire expanded, there was a need for more farmland, but there was not always a water source available. The Incas grew corn, cotton and squash. Garciasco de la Vega, speaking about the farming in the Incan Empire, said, “The engineers showed great cleverness and skill in supplying water for the crops since only scattered sections of the land could grow corn” (Document 4). Their success with irrigation helped them expand their empire. Without it, it would be more difficult for them to subsist in a growing empire.
This statement ensures the reader that the dam was built “for the people” doing this without stating any facts that prove the statement. This statement also does not state why the U.S. government built Glen Canyon dam.
Americans today tend to believe that the Colorado River drought has been a recent occurrence, although drought relief strategies have been implemented since early 1997. To summarize, in the book The Colorado River Basin Drought Planning and Organizations, Colorado is named as the original state to acquire a drought relief plan. For instance, various assume water levels are diminutive in the Colorado and blame is due to the previous ten years of drought throughout the United States. Although it is true that water levels are at a record low, initial plans in the early 1920’s to introduce manufactured structures into the water basin is the original reason Colorado’s water system began to be compromised. It follows, then the supplementary natural
The Colorado River is formed by small streams created by a huge amount of snowmelt from the Rocky Mountains. The ecology and flow of the river varies highly by region. The river is divided into two different regions, the Upper Basin and the Lower Basin. Beginning in the early 1900s, western states began to build dams in the Colorado river, diverting the water flow to fast growing cities like Los Angeles, San Diego, and Phoenix. The river now services over 30 million in the southwestern parts of the United States and Mexico (Patrick 1). Diverting the water of the nation’s seventh-longest river may be seen has a great accomplishment, however to others this is a great crime against nature. Over the past couple years the river has been running significantly low, since a drought has come up the southwest. At the lakes edge, “bathtub rings”, lines in the rock walls, can be seen showing the decrease in water level. It is recorded in some areas of the river that the water has lowered 130 feet since 2000. Some water resource officials say those areas will never be filled back to normal. The surrounding states must adjust to living with less water or further actions need to be taken to save the river’s water. There has been some talk about adding water to the river to replenish the river but nothing has hap...
One of the largest geographic physical structures in the United States is the Colorado River. Human activity and its interaction with this great river have an interesting history. The resources provided by the river have been used by humans, and caused conflict for human populations as well. One of these conflicts is water distribution, and the effects drought conditions have played in this distribution throughout the southwestern region. Major cities such as Las Vegas, Los Angeles, San Diego, and other communities in the southwest depend on the river. It provides water for over 20 million people, irrigation for 2 million acres of land, four thousand megawatts of hydroelectric energy, and over twenty million annual visitors for recreation purposes. Also, once in Mexico, the river provides water to irrigate half a million acres of farmland, and municipal and industrial water for 2 million people living in this delta region. The river distributes its flow from lakes and canals along its journey as well. Due to climate change, human demand, natural forces like evaporation and human-induced climate change this water supply is in conflict. Also, a recent change that began in March of 2014 will bring a temporary water surge to the delta of the Colorado River for the first time in many years to help restore this region, and it’s possible it could reach the Sea of Cortez once again.
The Three Gorges Dam on the Yangtze River will probably be finished by 2009 and will be the largest hydroelectric dam in the world.