Urban Flooding Risk Assessment Based on Numerical Simulation of Sub-catchment Area: A Case Study From Chengdu, China

Abstract

Urbanization and climate change usually result in frequent urban flooding. Since the floods cannot be avoided, the scenario simulation combined with risk analysis is an effective way to assess the disaster level and reduce direct damage loss when facing the emergency management problems. Different from the whole city dimension, the paper proposed a sub-catchment multi-index hesitant fuzzy evaluation model for the community planning level, and takes Jinjiang District of Chengdu city as the research object. Firstly, based on the PSR (Pressure-State-Response) model, the risk assessment system has been established in three aspects, including the current situation of urban drainage, the basic geographic information, and the social influence. Secondly, A total of 14 evaluation indexes were selected, among which the pressure index came from the calculation results of ArcGIS and EPASWMM5 model such as runoff coefficient, maximum water depth, etc. Thirdly, the expert hesitate fuzzy evaluation method was used to obtain the weight of 14 indexes of each sub-catchment. Finally, the 224 evaluation results were compared, and the urban flooding disaster risk map has been drawn. It is mainly concluded that 160 medium-higher risk areas were mainly concentrated in high built-up area in study area. Furthermore, the evaluation model is very useful as a decision-making tool for mitigation of the flood hazard and its associated risk.