After the formation of the Three Gorges Reservoir, what impact will it have on underground rivers?

Just a few days ago, it was formed in the upper reaches of the Yangtze River. No.5 flood of the Yangtze River in 2020? It has reached the high water level of 167.65 meters, which is the biggest flood peak encountered by the Three Gorges Reservoir since its completion in 2003, and it passed through the Three Gorges Reservoir normally a few days ago.

After China entered the flood season this year, although many places suffered from floods once every 50 years or even once every 100 years, the Three Gorges Dam project did play a huge role in flood control, which is also the greatest value and significance of the water conservancy project that we spent 17 years building. So, what impact does the formation of the Three Gorges Reservoir have on the underground river? How great will the impact be?

It has been several years since the Three Gorges Reservoir was built, and the flood peak record has been refreshed again and again. However, there is still some controversy about it, but the focus of some people's discussion has shifted from the initial immigration problem to the ecological problem. For example, what impact has the Three Gorges Reservoir had on the underground rivers in these areas?

In fact, in order to analyze the impact of water conservancy projects, we only need to find out what kind of topographical features underground rivers are common. If there are underground rivers under the reservoir, how will the impact on them change with time?

First of all, we should know that the construction sites of the Three Gorges Reservoir mainly involve 2 1 county and city, all in Chongqing and Hubei, and the underground river is a kind of underground karst landform. These rivers below the surface are essentially groundwater in karst areas.

Karst areas may exist in most parts of Yunnan, Guangxi and Guizhou provinces, and parts of Hunan, Guangdong and Hubei in South China. In other words, there is a high probability that there is no such underground river in Chongqing, but there may be karst areas in some parts of Hubei.

One of the most typical characteristics of underground rivers is that there is only an exit without an entrance. For example, the underground river system in Desu, Guangxi, and the underground river in Liulangdong, Yunnan are particularly famous representatives of underground rivers, with the maximum underflow of 390 cubic meters per second, and the latter can also reach 74 cubic meters.

The formation of such an underground river requires not only high temperature and rainy climate conditions, but also limestone areas. In fact, underground rivers often coexist with underground caves, and some caves can even reach the width of 100 meters and the height of tens of meters, which is why some underground rivers can be wide enough to row in them.

I believe many people have visited the underground karst landscape, and underground rivers and caves are the main components of this landscape. These underground structures can form such a special landscape, in fact, because these rock masses are soluble, and the places where various structural planes intersect are more likely to form caves for everyone to see. The movement rhythm of groundwater will also accelerate with the increase of caves, that is to say, in the process of forming underground karst landforms, the changes of groundwater and caves are synchronous.

Although it is mentioned at the beginning that there may be underground rivers in some parts of Hubei, the construction site of the Three Gorges Reservoir involves some parts of Hubei. However, before the construction of the Three Gorges Reservoir, after strict geological investigation and research, such a huge water conservancy project that takes 17 years cannot be decided by patting the head. From the construction process of the Three Gorges Dam water conservancy project, we can feel that it is indeed a great and arduous project:

Anyone who knows more about the history of the Three Gorges Project should know that as early as 19 18, Dr. Sun Yat-sen put forward the initial idea of building the Three Gorges Reservoir, but the time has come when 1992 "Resolution on Building the Three Gorges Project on the Yangtze River" was officially passed.

Construction preparation started on 1993, construction started on February 1994, river closure was completed on 1997, the Three Gorges Dam was completed in 2006, the water depth of the first experimental reservoir reached172.8m in 2008, and the completion acceptance was completed in 2009.

Up to now, the Three Gorges Dam has been in operation for many years, and nothing special has happened. Although there is no special data to find out how many underground rivers there are under the Three Gorges Reservoir, I believe these factors were carefully analyzed by experts who did geological survey in those years. But at least I think that since the Three Gorges Reservoir is located in these areas, it is unlikely that there will be too many underground rivers or even no such landforms at all.

After all, the main landform of the Three Gorges reservoir area is actually granite, not limestone. Granite is characterized by compactness, hardness and good weather resistance. Even in these places with subtropical monsoon climate, the probability of forming an underground river is very small, but if it is destroyed, it can only be integrated with the reservoir itself.