The root cause of flood disasters in the eastern plains of China are as follows:

1.In terms of climate, the eastern monsoon area is mostly tropical, subtropical or temperate monsoon climate, with rain and heat in the same period, and heavy precipitation.

2.In terms of terrain, the terrain is low and flat (depression), which is not conducive to flood discharge; on rivers, landslides, debris flows, river bends, riverbeds are blocked, and small longitudinal slope.

3.The eastern monsoon area is dominated by farming operations, and paddy fields are fragmented by the dense water network. The man-made causes of flood disasters are: vegetation destruction, lake reclamation, wetland reclamation, river sand excavation, dam destruction, unreasonable urban planning, etc.