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Recently there is some criticism about the environmental problems caused by the Three Gorges Dam, the biggest dam in the world, and the biggest building project since the Great Wall of China, which started 2500 years ago. Even one of my friends wrote a blog entry, in which he describes the project as a complete flop and predicts that the project will be blasted, due to severe environmental problems the project will cause.
Being no water expert, I cannot give answers to such questions as how severe damages the project has caused to the environment? Therefore, rather than answering these questions, this article only provides some food for thought.
What environmental problems are there? I googled and baidued (Baidu a very powerful Chinese search engine) news about environmental problems about the Three Gorges Dam, and got quite a few entries. The environment-related problems are summarized as follows:
1. Water pollution in the reservoir of the dam. The reason might be that the water flows slower than before in the upper reaches and its dilution function weakens. Another cause might be the relocation of the former reservoir residents.
As far as I know, the government has allocated 4 billion Yuan to deal with the pollution in the reservoir of the dam. And the annual power generated by the dam will replace 50 million tons of coal, reduce the emission of carbon dioxide by 100 million tons every year.
2. Silt. Silts will pile up before the dam and cause floods upstream of the dam.
It is possible. The silt problem was said to have been basically resolved as early as in 2003. I once watched an episode in Discovery and learnt that silt is a very serious problem in large dams. Does it work? I guess time will tell. I do not say I am not confident about it. I always believe there is a way out.
3. Earthquakes. According to Discovery, the dam might trigger earthquakes because of its weight pressing down the earth's crust.
It is said that the building of every large dam might trigger an earthquake. According to the authorities, minor tremors might be possible, but large ones are impossible. The biggest earthquake is expected to be below 3.5 magnitude, while the Three Gorges Dam can survive 7 magnitude earthquakes.
My friend has asked me to accompany him to the dam next year and I have accepted. Contact me if any of you guys are also interested in it.