Measure of Flood and Waterlogging in the Coastal Lowlands

China's coastal lowlands are easily endangered by flood and waterlogging because of the low and flat relief, the concentrated precipitation during the aestival period, and much more water coming from the upper and middle parts of rivers. Taking the coastal lowlands of Jiangsu province as an example, this paper creates a measure model to describe the inundation strength, and furthermore to analyze the significance of disaster mitigation.