What impact does the Three Gorges Project have on hydrology in the upper reaches of the Yangtze River?

Advantages and disadvantages of the Three Gorges Project

Because of migration and relocation, the plants in the Three Gorges reservoir area are on the verge of extinction. No one knows whether the pickled mustard tuber in Puling will be called pickled mustard tuber in the future, but because of soil erosion, the flowing river water has become stagnant water. How to prevent white pollution from environmental protection in reservoir area. Where did the flood flood reach during the flood season?

There is a saying that the Three Gorges Project will contribute to the sustainable development of the economy and will not increase greenhouse gas emissions, because it is not thermal power generation.

If you want to make huge profits, you must pay a huge price. The damage caused by the dam is also quite serious: more than 6,543,800 people have to move, and the fertile riverside land will be submerged; Rare and endangered species may be threatened with extinction; Some important historical sites will be submerged, some of which can even be traced back to more than 2,000 years ago.

Other impacts include: irreversible changes in hydrological characteristics of thousands of kilometers of rivers, destruction of fisheries and aquaculture, complex changes in downstream flood areas, and the possibility of increasing rather than reducing certain floods.

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 inundation. 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 1 10,000, and may be close to10.9 million. In this part of the immigrant population, urban residents account for a considerable proportion. Therefore, the resettlement work of the Three Gorges Project is more difficult and costly than before. Due to the lack of suitable places to resettle so many immigrants, the resettlement 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 upstream of the reservoir, which have been overpopulated in recent years. Resettlement 1 ten thousand people's production and life is undoubtedly equivalent to rebuilding a society. The original economic structure will be disrupted, and the 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 there are many factories flooded by the Three Gorges Project, and the losses are also great. Although the flooded factory can be relocated, the original system of mutual cooperation and coordination will be disrupted due to the suspension of production, which will cause great losses to economic development.

The most important thing is the lack of humanity in the ancient towns along the Yangtze River. Intangible cultural heritages such as ancient tunes and songs have lost the soil on which to develop, and are unfamiliar in other places, especially those dialects and local operas, which can no longer be developed and passed down.

In addition, for agriculture, the aforementioned 14000h square meters of fertile land will sink into 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 Yangtze River is rich in fish resources, but it is easy to be destroyed. 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 conform to the living characteristics of these fish, it is possible to affect the species and food sources of fish.

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 Siberian crane, which is its wintering habitat in the middle and lower reaches of the Yangtze River and 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, which takes away 50 ~ 10 billion tons of sediment every year. Although it is difficult to predict the velocity of sediment in reservoirs, experts generally believe that under normal circumstances, the sediment carried by rivers will be intercepted by dams every year. If this hypothesis holds, after 100 years, the sediment carried by the Yangtze River will fill the reservoir. Sediment deposition in the reservoir will have an impact on the downstream. For thousands of years, the Yangtze River Delta has been using this sediment as a nutrient source for farmland and fisheries. Opponents of the Three Gorges Project warn that the velocity of sediment near the reservoir tail will increase, which will seriously affect the navigation of the upper reaches in the dry season. Sediment at the end of the reservoir will also raise the river bank. The problem is that it is impossible to accurately predict the sediment deposition rate of the reservoir. This situation may make the economic benefits much lower than expected. Even if there is a reliable record of the deposition rate, it is difficult to predict the deposition rate and location.

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 construction of the Three Gorges Dam has not been fully verified. There are about 330 large reservoirs in China, of which 230 have serious sediment problems, resulting in a decrease of 6,545 in total storage capacity.

There are many other factors that will affect the Three Gorges Project. The area where the reservoir is located is also 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 of square ships passing through the dam. Once one of the five closely connected gates fails, the navigation of the Yangtze River will be interrupted. Similar problems have occurred in Gezhouba's shiplock elevator. But it has only one gate, which is technically much simpler than the lock design of the Three Gorges Project. A 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 intrusion in 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, ecological environment damage and reduced economic benefits are even more worrying. We build water conservancy projects to make human beings live better on this "water" ball, but if there is no effective and meticulous design and thinking, the harm may be even greater. 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.