Why did Yu's father fail to build a dam to stop water?

In ancient times, the Yellow River, as the birthplace of Chinese civilization, had an incomparable position with other rivers. However, due to the harsh natural conditions and low productivity during the slave society, it is impossible to completely eradicate the Yellow River flood. The main cause of the flood is the influence of the natural environment (precipitation is concentrated in heavy rain, the terrain is rugged and complex, and the three-level geographical ladder falls greatly). Damming to stop water is of course a method, but it can't be used in fast-flowing rivers (the productivity of slave society is low, and the dam is not tofu residue, but it is not as good as the Three Gorges), so Dayu's father will fail. But it is feasible for Dayu to combine embankment construction with river dredging. Damming is used to stop the gentle water flow, and dredging the river course is used to dredge the river course with large drop and high speed, which is beneficial to the diversion of the river. Therefore, it is successful.