It's hard to see Huang Heqing after 1000 years. Why did the Yellow River clean up 10 times during the 26 years of Song Huizong's rule?

We call the Yellow River the Mother River, because it has nurtured a large number of people nearby, but the Yellow River has a very bad temper, that is, it often floods, and once it floods, it will endanger the people near the Yellow River and cause great disasters to the people every time. Therefore, many people hope that the Yellow River will not be flooded, and emperors of all dynasties have invested a lot of money, manpower and material resources to control the Yellow River. Another feature of the Yellow River is that it is very turbid, but during the reign of Song Huizong, a very, very strange phenomenon appeared, that is, during the 26 years of Song Huizong's rule, the Yellow River was cleaned up 10 times. It is so strange because there is a proverb that Huang Heqing is hard to see in a thousand years. What is the reason?

First of all, let's understand why the Yellow River turns yellow, mainly because it passes through the Shaanxi Plain when it flows down from the Qinghai-Tibet Plateau. However, there are a lot of loose soil in the Shaanxi Plain, which will be taken away after the water flows, so it will become very turbid when it flows down in Shaanxi. Therefore, people at that time made the Yellow River clear or turbid, adding another layer of meaning, that is, if the Yellow River becomes clear, it represents the emperor at that time and the society is harmonious.

Then why did the Yellow River pass 10 times in 26 years and become a poor Song Huizong with a low historical evaluation? One of the reasons was the climate problem at that time. First of all, during the Song Huizong period, there was a very serious drought in the upper reaches of the Yellow River, and it happened many times. As a result, there is little water on the surface and the water flow is greatly reduced, so there is less sediment brought downstream, so the water will be clearer than before. The second reason is that during the Song Huizong period, there were some big floods in the Yellow River area. After these floods, the direction of the Yellow River changed and there was no mud drought.