Three Gorges Dam : good or not ?

The Three Gorges Dam is one of the greatest engineering project that the world has ever seen. It is 2.3km long , 184m high, and took 12 years to complete. Its 34 generators will produce 22,500 MW of electricity. This is praiseworthy as a source or clean, renewable energy.

The dam will also help control the flow of the Yangtze, which is known to overflow dramatically at regular intervals causing terrible floods that have killed sometimes hundreds of thousands of people. In periods of droughts, the reservoir will provide water to farms downstream.

But the dam is not just an engineering marvel, a green economic powerhouse, and a way to save millions of lives over time. Its main criticism is that it will create a giant lake that will need the relocalization of many people and the destruction of some old towns and villages and of some of the biodiversity upstream.

But is it really that bad ? I can't see what's the problem with asking some people to move house when it can save many lives. The environment issue isn't even one as it will prevent natural catastrophes by controlling the mighty river's flow. It will reduces pollution and green house gases. Overall I think it is a commendable and unavoidable project. Anybody care to disagree ?

I am in favour of the dam. It's not just a whim of the current Chinese government to show the world what their engineers can do. The project originated with Sun Yat-sen in 1919, was taken over by the Nationalist government of Chiang Kai-shek, then again by the Communists under Mao and his successors.

I have seen a documentary that depicted the project in a negative light, emphasising only the fact that a few peasants would be expropriated and ancient villages would end up under water. That's trivial, in my opinion. The dam is so much more than that. I agree with everything written above. If there is one river in the world that needed a dam it is the Yangtze.

What's so mind-boggling is that the Three Gorges Dam will produce 10% of China's electricity ! Each turbine will have the production capacity of 20 nuclear plants ! And that's all eco-friendly renewable energy.

Then, the river Han downstream of the dam will be diverted northward towards Beijing to cope with the seasonal drought in summer and the advance of the dessert.

Economically, high-tonnage ships will be able to travel all the way up to Chongqing in Sichuan, China's most populous city, now nearing 35 million inhabitants.

The sedimentation problem should not be overlooked. It's not just sediments but also big rocks that are transported by the river. They could block the dam and damage the turbines. If sediments fill up the dam the cost of dredging will be important.

If sediment cannot flo freely along the river, the waters will cause erosion in lieu of fertilizing the plains.

Finally, the ecological issue is serious. There is so much pollution flowing down the Yangtze that the lake created by the dam will quickly become a cesspit devoid of life. How are the Chinese planning to clean up the industrial waste in the new lake ?

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Originally Posted by Gyabuchaa

The sedimentation problem should not be overlooked. It's not just sediments but also big rocks that are transported by the river. They could block the dam and damage the turbines. If sediments fill up the dam the cost of dredging will be important.
If sediment cannot flo freely along the river, the waters will cause erosion in lieu of fertilizing the plains.

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The sediments needed to fertilize the land or prevent erosion will come from the hundreds of tributaries downstream of the dam. Sediments can be evacuated by opening the gates once in a while. Big rocks and so on can be stopped with wire netting, then evacuated too. It's not easy, but the dam will produce 10% of the country's electricity in clean energy. It's worth the effort.

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Originally Posted by Gyabuchaa

Finally, the ecological issue is serious. There is so much pollution flowing down the Yangtze that the lake created by the dam will quickly become a cesspit devoid of life. How are the Chinese planning to clean up the industrial waste in the new lake ?

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Pollution will be created by factories anyway. It won't cause more environmental damage if it stagnates in the lake than if it is allowed to go all the way to the sea. Its just a matter of where the pollution goes, not a matter of quantity. I don't think it is preferable to let heavy chemicals pollute the China Sea, which feeds hundreds of millions of people in China, Korea and Japan and is already overpolluted. The dam might be an opportunity to install water treatment plants - something you cannot do in the sea.

It's hypocritical (or just logically mistaken) to say that the Three Gorges Dam will create more pollution when it facts it will replace lots of highly polluting coal and gas power plants for 100% clean and renewable energy. The pollution in the river is an entirely different problem, which should be solved by asking factories not to discharge toxic waste in the river but send them for recycling instead. You can't blame the dam if factories don't do their job.