Assessment Of Urban Rainstorm Waterlogging Based On Drainage Model And GIS Fuzzy Evaluation

Recently,with the increasing urbanization effect,the rainstorm has often become the focus topic.The government is gradually increasing the investment of the prevention and control system,but the construction effect is not optimistic.Serious torrential rains have a huge impact on personal safety and social economy.Therefore,it is necessary to conduct a risk assessment of urban rainstorm waterlogging disasters so that government departments can make risk decisions based on the results of risk assessment.Through the analysis of risk theory,the fuzzy comprehensive evaluation model of rainstorm waterlogging is established.Yifeng,as a specific research case,the DS drainage model is used to simulate its flooding situation in the 50a rainstorm.Finally,the simulation results are imported into Arcgis to complete the process of fuzzy comprehensive evaluation.In general,the main points are as follows.(1)Based on the theory of disaster risk,the three components of the risk in heavy rains are discussed.In this study,the advantages and disadvantages of traditional risk assessment methods are discussed,and the problems existing in the current risk assessment of storms are pointed out.In this study,"index system method,drainage model method and GIS method"are well combined to complete risk assessment.(2)The fuzzy set,risk fuzzy set and fuzzy comprehensive evaluation are organically combined as a complete theory.The three risk elements are used as the criterion layer.The submerged depth,submerged area,submergence time,ground elevation,ground slope,impermeability,building density and POI density are used as indicator layers.Based on the above multi-layer structure,the fuzzy comprehensive evaluation model of urban storms is constructed.(3)The"1D-2D"coupled drainage model,as is validated in this study area,is used to output the hazard factor data in the assessment model.The smaller rainstorms of 0.5a~5a are used to check the running status of the pipe network and nodes,and the submerged depth,submerged area,submergence time of the study area are obtained by the heavy rainfall simulations of 10a~100a.(4)The grid calculator tool in Arcgis is used to implement the matrix solution process of the fuzzy comprehensive evaluation model.The grid and the catchment unit are used as the evaluation unit to carry out the superposition operation of the grid layer,and finally the risk distribution map of the rainstorm in the research area at 50a is obtained.The results showed that the risk areas of"very low,low,medium,high and extremely high"in the study area are 1.42km~2?0.14km~2?0.09km~2?0.08km~2?0.84km~2 respectively.