what is the natural cause of the yangtze river floods?

You know, Yangtze River has many tributaries. During the rainy season, the tributaries bring much water to the Yangtze River. Because the middle and lower parts of the Yangtze River are flat, the floods run randomly so that many areas are attacked.

However, Three Gorges Dam has been built. One of its functions is to prevent the floods. After the dam is put into use, the floods seldom appear.