Research On The Construction Of Urban Multi-objective Stormwater Storage System Based On Waterlogging Risk

With the process of urbanization in China,great changes have taken place in the use of urban land.Coupled with the frequent occurrence of extreme rainfall events caused by global warming,the increasing frequency of rain flooding has become an important problem affecting the development of Chinese cities.According to the analysis of the research status of stormwater storage and waterlogging risk in China,in recent years,the sponge city construction advocated by China has alleviated the urban stormwater problem to a certain extent from the watershed scale to the urban micro-scale.However,less consideration has been given to the stormwater control measures at the urban mesoscale.Moreover,in the face of extreme rainfall,sponge city system is fundamentally unable to solve the urban waterlogging problem with high risk.At the same time,the traditional waterlogging risk only considers the single danger,and there is little research on the economic loss caused by the city,and it is difficult to apply the result of risk assessment to the urban planning practice.Therefore,this paper starts from the urban area scale and identifies the key areas of waterlogging control based on the risk-loss waterlogging risk assessment.Combined with the urban storage space,the multi-objective optimization model is used to try to explore the construction method of the urban stormwater storage system with the combination of grey and green.This article selects the changsha wangcheng slope area as the study area,the study of the geographical hydrology,drainage system and construction of land investigation and data analysis,and based on the hydrological models for 20 years rainfall flood simulation scenario rain,according to the simulation results combined with different land use types and loss rate of inner land unit economic loss,the loss of waterlogging risk-the risk matrix to waterlogging risk assessment.By analyzing the storage space of the research area,the multi-objective optimization model is established,and the optimal solution of grey storage design is obtained by the optimization algorithm.Then by comparing the waterlogging risk and the space position of the storage after the gray optimization,the design layout of the green storage was obtained to solve the remaining waterlogging.Finally,the urban stormwater regulation and storage are graded by mesoscale and micro-scale,and the gray-green coupling regulation and storage system planning is formed.It is found that two kinds of waterlogging problems caused by the overflow ofdrainage pipe network and urban impervious surface runoff are found through the evaluation of waterlogging risk through scenario simulation.The risk and loss degree of waterlogging in the coupled land can better reflect the characteristics of waterlogging in the land space,and the functional properties of different land and the different asset properties of similar land have a certain impact on the risk of waterlogging.Through the multi-objective optimization model,the specific construction location and volume scale of the storage tank are obtained,and the design scheme can solve the 60-80% waterlogging problem,which is an important way to solve the overflow of the drainage system.Optimized found near unsolved waterlogging is partly a result of the overflow lack meets the storage space of the storage pool to given water,one part is produced by urban surface runoff together to low-lying water,so the grey to regulate the optimized waterlogging risk combined with the corresponding storage space,green storage control,can better solve the problem of the waterlogging.From the perspective of urban planning,the capacity of urban regulation and storage is fully explored,and a stormwater regulation and storage system for flood risk is constructed.The focus of this paper is to explore the optimization method of urban stormwater regulation and storage,to understand the danger and economic loss characteristics of stormwater flooding in cities,so as to adjust the spatial layout of the planning of stormwater regulation and storage,make full use of the space of urban regulation and storage,carry out accurate control of urban waterlogging,and promote the sustainable development of cities.