What caused Shidawei in Lujiang, Anhui Province to burst its banks?

The most direct reason is the once-in-a-century rainy weather, and the high water level in Chaohu Lake continues to rise, which leads to the dike being soaked for a long time and eventually leading to the dike collapse.

First of all, Chaohu Lake suffered from long rainy weather, and the time span was too long. According to the situation in previous years, the rainy weather lasted less than a month, and the rainy weather lasted for 50 days, often encountering short-term heavy rainfall, which led to the continuous rise of water level. Secondly, this long-term heavy rainfall process is nationwide, and the whole Yangtze River basin has experienced it. From upstream to downstream, it was hit by heavy rain. The Yangtze River was flooded for the third time. Although the Three Gorges Dam has weakened the water level pressure in the upper reaches of the Yangtze River, Hubei in the middle reaches is also facing heavy rainfall, and the water level of the Yangtze River has reached an extremely high value, which leads to the high water level pressure in the Anhui section of the Yangtze River and the flood control situation of dikes is not optimistic. In this case, the only spillway in Chaohu Lake has failed. As the only outlet of Chaohu Lake, it is in name only, which is also the reason why the water level of Chaohu Lake is difficult to drop, because a large amount of flood backlog can not be discharged in time and effectively.

On the other hand, all the rivers around Chaohu Lake flow to Chaohu Lake, which also makes the water level of Chaohu Lake rise too fast under the influence of rainfall, which poses a great threat to the surrounding dikes. However, due to the geographical location and soil quality of the dike, Shidawei section collapsed under the strong pressure of high water level and finally burst its dike. On the one hand, due to the shortage of flood control personnel, the entire Chaohu Lake is in a state of wartime flood control, and it is difficult to fully implement the 24-hour patrol of the dam. Therefore, the failure to find the danger in time and effectively is also the main reason for the levee breach. Before the arrival of reinforcements from all over the country, the general flood control work is difficult to deal with. From the fact that the excavator was swept away by the flood, it can be seen that many factors caused the breach, such as high water level soaking and drilling, early water inrush and rapid flow, and insufficient personnel and equipment.