Risk Assessment Of Urban Waterloggoing In Qingyang From The Perspective Of Sponge City

In recent years,the accelerated urbanization process in China has triggered dramatic changes in the urban water cycle process.This has resulted in a rise in heavy rainfall,watershed yield,and sink flow coefficients,increasing the risk of urban flooding.Consequently,the urban flooding problem in China has become more severe.This thesis selects Qingyang as the research area.Based on the collection and analysis of previous research data,it sorts out and summarizes the causes of urban water accumulation in Qingyang,and clarifies the impact of different factors on water accumulation and the resulting rainwater pollution;Then,based on needs,a field survey was conducted in the study area,and combined with existing basic data to obtain basic model data.After that,a model was established using InfoWorks ICM to simulate regional waterlogging.On this basis,the established prediction model is parametrized,validated,and simulated using multiple precipitation data information to comprehensively evaluate the flood disaster risk predicted by the model,and combined with other relevant technologies to simulate the flood disaster after the sponge fault transformation,thereby quantitatively evaluating its contribution to the prevention and control of flood disasters.The main work of this paper is as follows:(1)Utilizing InfoWorks ICM model software,we can construct and enhance the drainage model for the study area of Qingyang based on the sponge city concept.The model ’ s parameters are rated and calibrated using observed rainfall data to create a more reliable drainage model.(2)Set different simulation schemes based on the precipitation of different repetition periods.Based on this,the model was used to compare and analyze the situation of node overflow,ponding depth,and water pollution under various modes.The study found that with the extension of the repetition time,the urban rainstorm spread and accumulated significantly.The accumulation phenomenon is influenced by factors such as rain intensity and precipitation,and the precipitation within each field has a significant impact on the diffusion and accumulation phenomenon.The main factors causing the occurrence of waterlogging disasters in the urban area of Qingyang are: the drainage pipe network of the urban water supply system has a relatively small water carrying capacity,the topography of the ponding area is relatively low,and the water permeability is relatively large.(3)By utilizing the scenario simulation methodology,we were able to evaluate the risk of urban flooding,and subsequently produce a flood hazard risk map.The risk of flood disaster occurrence in the study area of Qingyang was analyzed using this approach,and it was observed that there was an increase in flood risk with the extension of reproduction time.In addition,high-risk areas tended to expand outward.The study area was predominantly classified as medium-risk,with the low-risk areas being widely dispersed,primarily along the main roads.(4)Analyze the problems of internal flooding and its associated disasters from various aspects such as water safety,water environment,water ecology and water resources,analyze research methods about the urban waterlogging risk,integrate and construct the hydraulic and water quality model of Qingyang,including: current situation model,large sponge planning model,and typical plot small sponge design model.The model is used to evaluate the current situation,planning,and design plans,including:annual total SS removal rate,drainage network capacity,flooding risk level,total annual runoff control rate,flooding remediation plan comparison,etc.And apply these findings to the assessment of urban waterlogging risk in Qingyang.(5)By incorporating sponge measures in the constructed urban waterlogging risk model,a model for sponge reduction and control was developed.According to the simulation results,these sponge measures can effectively control overflow,waterlogging,and pollution situations in the watershed.Furthermore,data indicates that sponge retrofitting can effectively manage the risk of flooding and significantly reduce the likelihood of low recurrence periods.Additionally,the reduction and control effect was found to be higher in the old city compared to the new city.These results demonstrate the effectiveness of sponge retrofitting in controlling the urban waterlogging risk in Qingyang city.