Risk Assessment Of Urban Storm And Waterlogging Disasters At Different Spatial Scales In Shenzhen

Against the background of global warming and the current urbanization process,the frequency,intensity and disaster losses of urban rainstorm waterlogging disasters in China presents the increasing trend year by year.Risk assessment of urban stormwater flooding is one of the important non-engineering measures to prevent disasters and reduce disaster risks and losses.Carrying out rainstorm waterlogging disaster risk assessment can provide a theoretical basis for flood risk management and a scientific basis for disaster prevention and mitigation strategies for emergency departments.Therefore,based on the risk assessment theory of urban rainstorm and waterlogging,this paper takes Shenzhen region as the empirical study area to carry out urban rainstorm waterlogging risk analysis and evaluation from different spatial scales.The main research results are as follows:(1)Based on the analysis of the concept and model of disaster risk,the assessment framework and process of urban rainstorm and waterlogging disaster risk are proposed.This paper analyzes and integrates the different urban rainstorm waterlogging risk assessment methods,and puts forward the conclusion that for research areas with different spatial scales,appropriate assessment methods should be selected for rainstorm waterlogging risk assessment.(2)Using Shenzhen as a large-scale empirical research area,a risk assessment index system for rainstorm and waterlogging disasters in Shenzhen city was constructed,and a fuzzy comprehensive evaluation method was used to evaluate the risk of flooding disaster in Shenzhen.The results of the study show that the high-risk areas of Shenzhen are mainly distributed in the western part of Bao'an District,Futian District,Luohu District,Longgang District and part of Dapeng New District.Risk-leading factors vary in different regions.(3)Taking Shenzhen Minzhi district as a small-scale empirical study area,a risk assessment method based on scenario simulation was selected.Collected the drainage system and geographical information of the Minzhi district,constructed a one-dimensional and twodimensional coupled urban rainwater model for the study area.Selecting two actual rainfall data and the Infoworks ICM model to verify the model,the verification results show that the model has good accuracy and reliability.(4)Analyzing the waterlogging situation in Minzhi district based on urban rainfall and flood model simulation result,a waterlogging risk assessment index system in the Minzhi district was constructed.A risk assessment of rainstorm and waterlogging disaster in the Minzhi district was conducted based on the hierarchical analysis method and Arc GIS.The risk assessment results indicate that the urban waterlogging disaster risk is mainly affected by the inundation,with the high-risk areas are mainly distributed in the gentler,more populated and more economically developed downstream areas.(5)In order to overcome the limitation of insufficient disaster sample data in urban center area,the indoor property inundation depth-loss rate curve of Shenzhen residents was fitted by the synthetic curve method.The total inundation loss of indoor properties in the study area was calculated to be 11.6 million yuan under the 100-year rainstorm recurrence period,providing technical support for the future urban inundation risk assessment.