Dynamic risk of urban flooding/waterlogging with attention to spatial heterogeneity of the underlying surface

Frequent urban flooding/waterlogging is a major challenge to society and economics． Accurate estimation of flood risk is important to improve urban flood control and drainage capacity, in the downtown area of Jincheng city in Shanxi province． A SWICA model was developed in this work to simulate flooding/waterlogging． A risk assessment framework was proposed from multi-source data, both subjective and objective comprehensive weighting were used, to analyze the dynamic flood risk of various rainfalls with different return periods． The volume of water in the pipeline network was close to capacity with the return period of 20 years, the drainage capacity of the pipeline network system was insufficient when the return period of rainfall was greater than 20 years． With increased rainfall return period, risk areas in downtown was found to gradually increase, mostly concentrated in areas along roads, intersections of street and the area with dense development． In southeastern downtown area, flooding/waterlogging risk increased significantly from 1 to 5 years of return periods． The area with high risk increased significantly with increased return period, by 224.614 hm² from 1 to 100 years of return period． Under the same return period of rainfall, the area with high and higher risk mostly concentrated in the central downtown area with dense development． With high vegetation coverage and relatively high elevation, the northeastern downtown area was with low risk．