A Method for Urban Flood Risk Assessment and Zoning Considering Road Environments and Terrain

Floods have been severely threatening social development worldwide. The occurrence of floods has multiple factors, and the flood risk considering road environments needs comprehensive analysis from meteorology, underlying surface, and urban road network. Thus, this study proposes an integrated method and constructs a road risk zoning model (RRZM). In the RRZM, submerged depth was obtained by the Soil Conservation Service (SCS) model, and the degree of road importance was obtained by the analytical hierarchy process (AHP) method. These two parts were used to characterize road vulnerability. Then the flood risk grade was evaluated based on the optimized artificial neural network (ANN). Finally, the results of flood risk assessment were obtained by road vulnerability and flood risk grade. The RRZM was applied to the Chang-Zhu-Tan Urban Agglomeration (CZTUA), China. The results showed that the spatial distributions of flood risk and the extent of road damage varied remarkably in different cities. Changsha was the most sensitive city to floods in the CZTUA. The flood risk zones were classified into six levels, and the vulnerable road sections identified from the risk zones at level 6 in the maps carried more traffic volume than others. By comparing with existing methods, it was found that the RRZM effectively reflected the spatial characteristics of flood risk considering road environments. It provides a new perspective for urban flood risk assessment and disaster response decision-making.