The Hoover Dam is a concrete arch-gravity dam in the Black Canyon of theColorado River, on the border betweenthe US states of Arizona and Nevada. Itwas built between 1931 and 1936 and wasopened on September 30, 1935, byPresident Franklin D. Roosevelt.The dam was named afterPresident Herbert Hoover; noteveryone was happy about this.According to: http://en.wikipedia.org/wiki/Hoover_Dam
The main reason Hoover Dam was built was to control flooding by the Coloradoriver.The Colorado river was a huge problem. It had been flowing South-west towardsthe pacific ocean making great canyons. Melted snow from the mountains eachspring made the Colorado river a huge raging pile of water, flooding small valleysand ruining farm lands, cities, etc. In 1905 the Colorado river cut through itsbanks below the Mexican border and for two whole years pored unchecked intothe Salton sea. When the floods each spring ended, the river dried into a trickle.Crops withered and died. All living things suffered. Some gave up and went elsewhere, others stayed to fight.Arthur Paul Davis, first reclamation director and chief engineer understood theirproblem. He spent years traveling up and down the river studying. Build a highdam and a deep canyon up stream to control the river he recommended. In 1918Davis reported his findings and proposals to Congress. Congress responded in1928 to build a dam to control the Colorado river and the all American canalsystem to deliver water to farm lands on the lower river. In 1930 presidentHerbert Hoover signed the appropriation bill to begin construction. Men andmachines started building in 1931 and finished in 1936. According to : http://www.youtube.com/watch?v=dXv9V7qsjNI
The Hoover Dam caused much damage. For example, many plants in thefloodplain were threatened because they could not reach the new depth of the groundwater table. Bighorn sheep, coyote, desert tortoise, ground squirrel, ringtail cats and the golden eagles’ existence are threatened because of the Hoover dam. They live in a delicate place that depends on specialized plant lives to survive. These plants are getting destroyed because of the effects of the Hoover dam and these animals take the consequences. There is also a big amount of pollution caused by all the automobile traffic. Many fish species have been affected by the Hoover dam. Mostly by the water temperature. The Hoover dam turbines lower the water temperature, which resulted in the immediate extinction of several species.According to:http://www.slideshare.net/Lengkengs/hoover-dam-and-the-negative-effects-on-environment-4204612
According to the U.S. Department of the Interiors Bureau of Reclamation, the Hoover Dam took five years to complete. Constructionbegan on the dam in 1931 and ended in 1936. The dam wascompleted two years ahead of schedule.
1. At its base, Hoover Dam is as thick (660 ft.) as two footballs fields measuredend-to-end.2. As many as 20,000 vehicles a day drive across the 45 ft. wide top of the dambetween Nevada and Arizona.3. There is enough concrete in Hoover Dam to build a 2 lane road fromSeattle, Washington to Miami, Florida or a 1.5 meter wide sidewalk around theEarth at the Equator.4. Each of the 10 meter wide water pipes can carry enough water to fill 900bath tubs in 1 second, or 960,000 cans of drink in 1 second.If you drink water from the tap at Disneyland, Anaheim or Sea World in SanDiego -- that water is coming from the Colorado River and Lake Mead, 300miles away.5. Every state in the USA furnished supplies and materials for the constructionof the dam.6. Between 1931 and 1936 when the dam was built, 96 men were killed inindustrial accidents. None were buried in the concrete.7. The mascot dog and favorite pet of all the construction workers during thebuilding of the dam was buried at Hoover Dam. The grave is near the HooverDam Tour Center and can be visited. According to: http://www.usbr.gov/lc/hooverdam/educate/kidfacts.html