The Three Gorges Reservoir will be the world s largest man made lake when impounded, and its impact

First, it will exacerbate the already acute contradiction in the reservoir area, which has more people and less land. When the normal water storage level of the Three Gorges Reservoir is 175 meters, 360,000 mu of cultivated land and orchard land will be submerged; In the resettlement areas, the relocation of cities, county seats, market towns, rural settlements, industrial and mining enterprises, and the rehabilitation of highways and other specialized projects will also occupy nearly 70,000 acres of cultivated land. If there are no appropriate and effective measures, we will only insist on leaning close to the nearest reservoir and only make efforts to expand the cultivated land, which will inevitably lead to large-scale deforestation and land reclamation, planting on steep slopes, causing new soil erosion, and further deteriorating the living environment.

In particular, after the state stipulated that land with slopes above 25 degrees must be returned to forests and grasslands, and slopes below 25 degrees must be transformed into terraces, the environmental capacity for rural resettlement in the Three Gorges reservoir area has been further reduced. How to do both to enable rural migrants"You can move out, you can stay stable, and you can gradually get rich"It is also necessary to properly protect the ecological environment of the reservoir area and promote the transformation of the ecological environment in the reservoir area into a virtuous cycle, which has become the first important task in eliminating the adverse impact of the Three Gorges Project on the ecological environment.

Second, it will further aggravate the water pollution in some sections of the Three Gorges Reservoir area. Before the completion of the Three Gorges Project, the water pollution in some sections of the reservoir area was already very serious, but because of the large flow and fast flow rate of the Yangtze River, the Yangtze River has a strong ability to purify itself, and the consequences are not serious. After the impoundment of the Three Gorges Reservoir, especially in winter, the amount of water coming from the upstream decreases, slowing down the flow rate of the water body in the reservoir, and reducing the ability to reoxygenate and diffuse.

Therefore, in accordance with the national laws and regulations on ecological and environmental protection, the industrial wastewater and solid waste in the Three Gorges Reservoir area must be treated within a time limit; Domestic sewage and garbage must also be brought under control within a time limit, and this has become the second important task of eliminating the adverse impact of the Three Gorges Project on the ecological environment.

Third, after the Three Gorges Reservoir is impounded, some unstable collapse bodies and landslides will slide into the Yangtze River, and some will threaten the safety of local people's lives and property.

Fourth, after the impoundment of the Three Gorges Reservoir, the close-up landscape of the canyon formed by the low mountains on the upper part of the Xiling Gorge and some tributaries will be affected to a certain extent. It will also submerge both above-ground and underground artifacts in the inundated area. Therefore, it is necessary to do a good job in the landscape protection and development planning of the Three Gorges Reservoir area, and conscientiously implement it; In accordance with the state's laws and regulations on the protection of cultural relics, the rescue protection and excavation of cultural relics on the ground and underground has become the fourth important task in eliminating the adverse impact of the Three Gorges Project on the ecological environment.

It's like a geography ......

Hello everyone and welcome to this issue. Speaking of reservoirs, everyone is certainly familiar with reservoirs, almost all cities are now building reservoirs in the surrounding areas to supply urban water, and some reservoirs are also local attractions. The most famous reservoir in China is, of course, the Three Gorges, which is one of the most representative super projects in China since modern times, and the Three Gorges Hydropower Station is also famous in the world, but the Three Gorges is not a good name in the world as a reservoir.

The world's largest reservoir is Africa's Kariba Reservoir, which is located on the border between Zambia and Zimbabwe in southern Africa, with a total area of about 5,580 square kilometers and a maximum storage capacity of 185 billion cubic meters. The area of the Three Gorges Reservoir is only 1,084 square kilometers, less than one-fifth of the Kabli Reservoir, and the storage capacity is pitifully small compared with the Kabari Reservoir, with a total storage capacity of less than 40 billion cubic meters, which is more than four times that of the Kabli Reservoir. The slow-bend shows the enormity of the Kabari Reservoir.

Just as the Three Gorges Reservoir was formed by intercepting water from the Yangtze River, the world's largest reservoir intercepts water from the Zambezi River, Africa's fourth-largest river. It was built in the fifties and sixties, but in 2013 it was upgraded again. It is worth mentioning that Zimbabwe, one of the countries to which the reservoir belongs, was able to borrow money from China at the time of this upgrade, and the expansion project was also contracted by China's hydropower group.

In our impression, the construction of the reservoir means the destruction of the original local landform and ecological environment, and it is likely to mean the extinction of animals and plants, because of this, China's Three Gorges has always had a mixed reputation. But when the Kabari reservoir is built, it will at least benefit the local aquatic life. Today, the reservoir is one of the most important fishing areas in both countries, with more than 60 species of fish, as well as protected animals such as Nile crocodiles, hippos and elephants, making the Kabari reservoir considered the most vibrant ecological lake.

In addition to the development of the local fishing and tourism industries, the Kabari Reservoir also has drawbacks that cannot be ignored. According to relevant data, since the construction of the reservoir, the frequency of ** in the nearby area has increased greatly, only more than 20 ** above level 5, and small earthquakes below level 5 have never stopped. For Zambia and Zimbabwe, there is a price to be paid for enjoying the resources and economic benefits of the reservoirs.

In the long run, it is difficult to say whether this super-large reservoir is beneficial or harmful, but do you have any thoughts on this?

In a watershed, precipitation from the atmosphere flows from small rivers (part of the precipitation is absorbed by soil plants) from the mountain slopes to large rivers, tributaries, main streams, and finally into the sea, and the evaporated water from the sea surface is sent to the land to form rainfall, which is a complete water cycle. The whole river is a complete system of various materials and energy circulation, and the upstream and downstream, especially the upstream, have a great effect on the downstream. For example, soil from the middle and upper reaches of the river is carried to the estuary and deposited into alluvial plains and delta ecosystems, which are usually agricultural areas, but sediment problems in rivers can also affect water quality, and if soil erosion is severe, it will lead to the destruction of the soil layer (the soil layer is very thin, and the soil takes a long time to form, geological time), which can exacerbate various environmental problems.

In addition, water has energy, and the development of rivers is also a dynamic process, and the shape of rivers will change, and over time it will tend to a certain equilibrium.

Building a dam on a natural river is artificially cutting off the relationship between upstream and downstream. Dams over 15 meters are usually called dams, and there are about 50,000 dams larger than 15 meters in the world, which hold about 15 years of annual freshwater runoff.

Generally speaking, the impact of the dam on the natural ecological environment of the river basin:

The storage of water in reservoirs will reduce and alter downstream water supply systems, reduce downstream biodiversity, reduce fishery harvests, and reduce irrigated agricultural income. Changing the water supply also includes the transformation of the original seasonal natural water supply into an artificial water storage and release system.

The reservoir intercepts sediment and also intercepts the nutrients that are transported downstream. At the same time, the downstream river water will become clear, and the erosion force of clean water is greater than that of turbid water, which will increase the erosion of downstream river channels.

Fish migration is blocked.

The large amount of water stored in the reservoir can change the water temperature, affect the water quality, and also affect the aquatic life downstream.

The impoundment of water in reservoirs will produce greenhouse gases, and large water bodies may also cause ** and so on.

In addition, it is very important to note that although various assessments and calculations are made before the dam is built, human beings do not fully understand the river, and no matter how detailed the calculations are, the various changes in the river after the dam are completed, and in many cases the severity of the problem is underestimated. Sanmenxia is a good (very bad) example of this, where the sediment problem has greatly shortened the life of the dam, and the economic cost alone outweighs the cost.

Also, there is a conflict between the benefits of the dam. The simplest example, power generation and drought prevention, in order to generate electricity, for economic benefits, you need high dams and high water levels, but to prevent drought and irrigate, you need to release water. The discussion of the water level in Sanmenxia at the time also included how much more area would be flooded to achieve the predetermined power generation efficiency, and the serious impact on a tributary if the water level was raised.

Therefore, there are many competing interests between departments and districts and counties.

In addition, the dam will increase the cost of maintenance as it ages, as well as deal with a variety of problems that were not foreseen in the past.

Building dams is expensive and takes a long time, and the cost-benefit analysis of hydropower deserves careful analysis.

"Big project, big status, big job", the climate of the Chinese land "** air conditioning" has been destroyed, what to do Answer: It's cool!