Hydroelectric power is a kind of energy which is generated by the conversion of the power of falling water through the turbines in a dam. In order to get a strong falling water to push the turbines, water has to be raise to a high level, thus, a reservoir and a dam are need to achieve this purpose. When mentioning hydroelectricity, the first few terms come to us might be clean, green, and renewable energy. It seems to be a popular belief that hydroelectricity is a kind of perfect energy resource that has no impact on the environment and human beings, but in contrast to your belief, hydroelectricity is more harmful than you think to us. First, Hydroelectric power causes damage to environment. One of the reason if that the constructions of hydroelectric stations cause a loss of land. Hydropower is generated through the force of falling water, damming a stream or river to make a reservoir is the main method to raise its water level. The raising of water level means a large area of land will be flooded, which could include forests, agricultural land, and wildlife habitats. These lands which are around the river are often fertile soil, which are precious resource for the local farmers. A report from Brian Handwerk (2006) point out that, the largest hydropower plant in China whose reservoir is 410 mile long, flooded over 244 square miles, which is almost twice the size of Seattle city. Comparing to other types of power station, none of them will occupy such a large area of land as hydropower does. Power stations like nuclear stations or thermal power station can be relocated in case of cities expansion or in any other situations, and the land can be used again, but for hydropower, it seems to be impossible. Hydroelectric power also affects the wildlife in the aquatic ecosystem. The direct impact is contributed to the turbine in the dam. The dam cuts the river into two parts—upstream and downstream, and the tunnel in which the turbines are installed is the only way connects the two parts of the river. Wildlife like fish will be hit or killed by the turbines when swimming through the tunnel. The indirect factor is that the rising water level in the upstream of the river will bring down the temperate of the water. As a consequence, underwater plants and fish which rely on specific water temperate will failed to adapt to the change and result in dying out. According to a report, the population of the fish species which including three endemic ancient fish, Chinese sturgeon, River sturgeon, and Chinese paddlefish encountered a significant decline after the construction of the Gezhou dam in China (Xie, 2003).
Another negative factor that affects the environment is that hydroelectric power causes air pollution. In popular belief, hydropower is a kind of green energy and has no air pollution, but this is not the case. Contrarily, hydroelectric reservoirs products significant amount of greenhouse gas which will finally lead to global warming and climate changes. The reason is that the rising of water level floods a huge area of vegetation. Trees and plants which are flooded by water will die, rot and then decompose, throughout this process, greenhouse gases such as carbon dioxide and methane will be released to the atmosphere.
Beside the environment damage, the construction of hydroelectric stations has great impact on local residents. A huge among of people has to be displaced during the constructions of hydroelectric dams. As the water level rises, people who live around the dam will have to forever leave their homes which they have lived for many generations. More importantly, these immigrants, most of whom earned their livings by specific skills like fishing or tour guide in their homeland, might fail to continue their career and have to learn other skills to support their families. Worse, they might be jobless and become refugee, and these kinds of harm will last for a long period or even generations....
References: Handwerk, B. (2006). China 's Three Gorges Dam, by the Numbers. Retrieved from http://news.nationalgeographic.com/news/2006/06/060609-gorges-dam.html
Xie, P. (2003). Three gorges dam: Risk to ancient fish. Science, 302(5648), 1149-51; author reply 1149-51. Retrieved from http://search.proquest.com/docview/213586368?accountid=1230
Wines, M. (2011). The Three Gorges Dam faces problems involving pollution. Retrieved from http://www.nytimes.com/2011/05/20/world/asia/20gorges.html
Yardley, J. (2007). Chinese Dam Projects Criticized for Their Human Costs. Retrieved from http://www.nytimes.com/2007/11/19/world/asia/19dam.html?pagewanted=all
Lafrniere, S. (2009). Possible Link Between Dam and China Quake
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