Dams: Past, Present, and Future

Dams: Past, Present, and Future Paras Patel

The Hoover Dam is located on the borders of Nevada and Arizona, on the Colorado River. Construction on the Hoover Dam began in 1931 and was completed in 1935. Hoover Dam

The dam was built due to the cycles of drought and flood that had prevented agricultural growth in the southwest. The dam would also provide hydroelectric power and water supplies so that surrounding cities would be able to flourish. Hoover Dam

Hoover Dam • What type of ecosystem do you expect to be present around the Hoover Dam? • How do you think the ecosystem has changed since the dam was built?

The benefits of building this dam include water supplies for major cities and agriculture, as well as hydroelectric power for surrounding areas. This dam also put a stop to the drought and flood cycle that had been occurring for such a long period of time. The costs of building this dam, along with other dams on the Colorado river, include a decline in fish in the river and changes to the surrounding ecosystem. Hoover Dam

Some steps have been taken to try and reduce the steady decline of fish inhabiting the river. Fish ladders have been built at dams so the fish can still go upstream to spawn. Bypass tunnels have been made for fish traveling back downstream. Hoover Dam

Hoover Dam • Do you think it was a good idea to build this dam? Think about the costs and the benefits, and the effects each of them has had. • Should the dam be torn down or should it be left alone?

The Edwards Dam is located on the Kennebec River in Augusta, Maine. The dam was completed in 1837. Edwards Dam

There was much protest and controversy when this dam was proposed. The area where the dam was to be built was populated with fish that swam upriver to spawn. Many fisheries were located up and down the river. A fish ladder was created when the dam was built but it washed away and was never replaced. What would happen to the fish if a dam was built in the river? Remember that fish need to swim upstream to spawn. Edwards Dam

The Edwards Dam was built despite all of the protest and controversy. It powered seven sawmills, a gristmill (a mill for grinding grain) and a machine shop. The Edwards Dam was not initially designed to generate electricity. The first electric generators were installed in 1913. Edwards Dam

There were some benefits when the dam was initially built, such as providing mechanical power for the mills, and generating a small amount of electricity. In more recent years the dam was only used for the small amount of hydroelectric power it produced. Edwards Dam

The lack of habitat, and the lack of a fish ladder, led to a total decimation of the fish population in the river. The dam was also breached (broken through) several times, which cost the dam company a lot of money to fix. The costs of building this dam included a loss of habitat for nine species of migratory fish. These fish had been coming from the ocean to spawn in the Kennebec River for thousands of years. Edwards Dam

Edwards Dam • Think about the costs and the benefits that the dam had. Was it a good idea to build this dam? • Weigh the costs and the benefits. Do you think this dam should be torn down or left alone?

The Edwards Dam was the first dam to be demolished by the government, because the costs heavily outweighed the benefits. It was removed in 1999. Before After Edwards Dam

The Three Gorges Dam is currently being built on the Yangtze River in China. Three Gorges Dam Licensed under the GNU Free Documentation License. • The dam will be completed in 2009.

Three Gorges Dam • This dam is going to be the largest hydroelectric dam ever built. • It is going to produce a capacity of around 18.2 million kilowatts of power; this tops the largest dam right now by 40 percent. Picture by Thomas R. Danford, West Virginia Northern Community College

The idea for this dam was first proposed in 1919. Planning for the construction of this dam began in 1954. One of the purposes of this dam is to supply power to much of central China and its growing economy. Another purpose of this dam is to relieve the cycles of heavy flooding. A flood in 1954 killed 30,000 people and left one million people homeless. Three Gorges Dam

Three Gorges Dam This is the Three Gorges Dam, in the process of being built, on July 20, 2000

Three Gorges Dam • The benefits of this dam include generating enough power to keep pace with China’s economic growth and minimizing the danger of flooding. It will also reduce fossil fuel emissions so that there is less stress on the atmospheric environment.

The costs ofbuilding this dam include moving and resettling more than 1.1 million people, increased risk of landslides and earthquakes, and damage to the natural habitats in and around the river. Besides the many fish species that will be at risk, the Yangtze Dolphin, the Chinese Sturgeon, the Chinese Tiger, the Chinese Alligator, the Siberian Crane, and the Giant Panda will also be affected by the building of this dam. Three Gorges Dam

Three Gorges Dam • Think about the costs and the benefits, and the effects each of them will have. Do you think it’s a good idea to build this dam? • What effects do you think the dam is going to have on the surrounding environment?

Three Gorges Dam • When the dam is built what steps can be taken to alleviate some of the problems the dam will cause?

Work in some areas of the dam has been suspended, because the lack of proper approval by China’s State Environmental Protection Administration (SEPA). The SEPA claims that there was a lack of proper environmental impact checks at the underground power station under review China has also suspended 30 other large –scale projects in an effort to improve their environmental credentials. As of February the Three Gorges Project Corp is refusing to stop work on some of the questionable sites despite government orders, they will most likely be fined for these actions Update: Three Gorges Dam

Dams: Past, Present, and Future