Is the Three Gorges Dam destructive to river life?

When analyzing the environmental impact of the Three Gorges Project, China Academy of Sciences pointed out that the most destructive aspects of the project are large-scale migration and large-scale land flooding. Resettlement has always been a headache in the process of dam construction in China, especially in Sanmenxia, Xin 'anjiang and Danjiangkou reservoirs, where the number of immigrants exceeds 300,000 each time. However, the scale of migration caused by the Three Gorges Project is unprecedented. The dam project will inundate parts of 65,438+09 counties, including parts of Fuling and Wanxian with a history and culture of more than 65,438+0000 years, and parts of Chongqing. The total immigrant population exceeds 6,543.8+0,000, and may be nearly 6,543.8+0.9 million. In this migration, urban residents account for a considerable proportion, which makes the resettlement work of the Three Gorges Project more difficult and more expensive than before. Due to the lack of suitable places to accommodate such a large immigrant population, the immigration work has become more difficult. Due to the large population in China, suitable land has been reclaimed and occupied, and most of the population will be placed in the barren highlands in the upper reaches of the reservoir. In recent years, there has been an overpopulation. Resettlement of more than 6,543,800 people's production and life is undoubtedly equivalent to rebuilding a society and will definitely disrupt the original economic structure. Production order, work order and social order will lead to a long-term decline in productivity and slow economic development. Moreover, due to historical and traffic reasons, domestic industries are concentrated in cities and market towns along the Yangtze River. So the Three Gorges Project flooded many factories and caused great losses. Although the flooded factories can be relocated, the suspension of production will disrupt the original cooperative system and cause great losses to economic development. The most important thing is the loss of humanities in ancient towns along the Yangtze River, and the intangible cultural heritage such as ancient tunes and songs has lost the soil for development, making people in other places feel strange, especially those dialects and local operas.

In addition, for agriculture, the above-mentioned 14000h square meters of fertile land will sink to the bottom of the water, resulting in serious loss of land resources. As predicted in the planning of this huge project, it will have a great impact on the ecological environment. The fish resources in the Yangtze River are rich and fragile. Due to the dynamics of the river, the changes in the temperature and chemical composition of the river, and the changes in the natural living environment and food sources that meet the living characteristics of these fish, the species and quantity of fish may be affected, and the number of some species may drop sharply because they cannot adapt to the new environment.

In particular, the project will seriously affect the fish living in the middle reaches of the Yangtze River, which is the main habitat of thousands of rare fish unique to China, among which only the Chinese sturgeon and baiji living in the middle and lower reaches of the Yangtze River are more concerned. The completion of Gezhouba may have seriously affected the breeding of Chinese sturgeon, and the number of baiji has dropped to only a few hundred. In addition, another wild species worthy of attention is the endangered Siberian crane, whose wintering habitat is in the middle and lower reaches of the Yangtze River, which will undoubtedly be affected by the dam.

Sediment in the river will bring a series of complicated consequences. The Yangtze River is one of the rivers with the largest sediment volume in the world, taking away 5000-10 billion tons of sediment every year. Although it is difficult to predict the sediment velocity in the reservoir, experts generally believe that the sediment carried by the river will be intercepted by the dam every year. If this hypothesis holds, the sediment carried by the Yangtze River will fill the reservoir in 100 years. Sediment deposition in the reservoir will affect the downstream. For thousands of years, these sediments have been regarded as a source of nutrition for farmland and fisheries in the Yangtze River Delta. Opponents of the Three Gorges Project warn that the velocity of sediment near the reservoir tail will increase, which will seriously affect the navigation in the upper reaches of the dry season, and the sediment at the reservoir tail will raise the river bank. The problem is that it is impossible to accurately predict the sedimentation rate of reservoir sediment. This situation may make the economic benefits much lower than expected. Even with reliable records of sediment and deposition speed, it is difficult to predict the velocity and position of sediment deposition.

Taking multi-purpose reservoirs in India as an example, Murti, a water conservancy expert, said: "The annual sediment deposition rate of most reservoirs is 145% to 875% of the calculation speed during construction." Leopold pointed out: "Worldwide, the Three Gorges Dam was built without full verification. There are about 330 large reservoirs in China, of which 230 have serious sediment problems, resulting in a decrease in total storage capacity 14%. Due to insufficient analysis and design defects, some of these reservoirs have reduced their water storage by 50% in less than 65,438+00 years. "

The Three Gorges Project will also produce many other influencing factors, and the reservoir is located in an area prone to waterborne infectious diseases, such as schistosomiasis. A large amount of water in the reservoir will reduce the water flow downstream of the dam. Opponents of the project are also worried about the reliability of the interlocking doors in the dam square for ships coming and going. Once one of the five closely connected gates goes wrong, the navigation of the Yangtze River will be interrupted. Gezhouba's shiplock elevator has similar problems, but there is only one gate, which is technically much simpler than the shiplock design of the Three Gorges Project. The original free-flowing river will become a slow-flowing reservoir, and people are worried that flooded farmland and residential areas will release toxic substances and pollutants. The reservoir's control of water flow will increase the possibility of seawater invading Shanghai's underground aquifer, thus affecting Shanghai's water supply. In the final analysis, the impact of the Three Gorges Dam is unpredictable in advance. Once the dam is completed, its impact will last for decades or even centuries.

As can be seen from the case of the Three Gorges Project, every water conservancy project will inevitably produce many harmful aspects while it is being built. In particular, large-scale water conservancy projects, immigration problems, sediment problems, as well as the destruction of the ecological environment and the reduction of economic benefits are even more worrying. We build water conservancy projects to make human beings live on this "water" ball better, but it may still be harmful if we don't do detailed design and thinking. If a project is really put into construction and implementation, we must minimize the disadvantages it brings to us, so that people can benefit from it and not suffer from it. . Water conservancy project is not a single aspect, it involves all aspects of society, so the joint efforts of the whole society are an important way to succeed in water conservancy project.

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New research on climate change shows that the world is warming, and climate warming will increase the crimson rain in the mid-latitude areas. By then, the precipitation in the Yellow River Basin in China will increase, and whether the Yangtze River Basin can also maintain the water supply in the basin. After global warming, the increase of mid-latitude precipitation is uncertain, and the global environment deteriorates, making droughts and floods frequent and intensified. Perhaps North China is not short of water, or it may be even more short of water.

The main disadvantages of the Three Gorges Project are the threat of war, inducing earthquakes and destroying the environment and biosphere.