Comprehensive Evaluation Method Of Sponge City Based On The Storm Water Mode

For the past few years,large-scale urbanization has led to the rapid increase of impermeable surface area which changed the natural hydrologic circulation and resulted in serious floods disaster and runoff pollution.The traditional measures of rainstorm management can no longer meet the needs of new urban development strategy.However,Sponge city,as a new generation of concept of urban rainstorm management based on the idea behind low impact development,has been attracting more and more attention.The paper attempts to use the storm water model to simulate the running effect of sponge city.According to the guiding principle of sponge city construction,the factors that affect the construction of sponge city include water environment,water security,water ecology,water resources and economic benefit.Therefore,based on the comprehensive analysis of the influencing factors of the running effect of sponge City,the paper determines the hierarchy structure chart of the index.By using the analytic hierarchy process,the normalization method and the weighted sum method,the environmental benefits,economic benefits,social benefits and comprehensive benefits of various sponge facilities construction projects are quantitatively identified.A quantitative evaluation method of sponge city running effect is constructed after that.Finally,we can use the above evaluation method of sponge city to carry on the evaluation of the community sponge reconstruction project and the expressway sponge reconstruction project.The purpose is to verify the generality of"project design and evaluation method",and to select the best project.For the Guangxi Sports Center sponge reconstruction project,through the calculation we set up five sets of projects.Through the linear normalization and weighted summation method to obtain the comprehensive benefit of each project,we know that the comprehensive benefit of each project are 0.2583,0.2489,0.2521,0.2649and 0.2522,respectively.It is obvious that the fourth project which includes the rain garden 11253 m~2,grass ditch 4800 m~2,sunken green area 15000 m~2,permeable pavement 1200 m~2 and storage tank 3600 m~3 has the highest comprehensive benefit and the environmental benefit and economic benefit are the largest,so the forth project can be used as the best project.For the expressway sponge reconstruction project,through the calculation we set up four sets of projects.Through the linear normalization and weighted summation method to obtain the comprehensive benefit of each project,we know that the comprehensive benefit of each project are 0.2912,0.3002,0.3020 and 0.2947,respectively.Obviously,the comprehensive benefit of the third project which includes the rain garden 11253 m~2,grass ditch 4800 m~2,sunken green area 15000 m~2,permeable pavement 1200 m~2 and storage tank 3600 m~3 is the highest,and the environmental benefit and social benefit of the third project is higher than those of other projects,so the third project is selected as the best solution.The paper hopes to establish a quantitative sponge city evaluation method,which can better guide the sponge city construction plan comparison and sponge city performance evaluation.