The Study Of Spony City Construction Technology Based On Uwater Drainage

The new urbanization is people-oriented,pay attention to the harmonious development of people and city,but in the process of rapid urbanization,the human production and consumption capacity greater than the degradation function of city,so it have a certain impact on the environment,causing serious problems,such as city waterlogging,city heat island,black smelly water,shortage of water resources etc..Sponge city construction model can reduce the initial rainfall runoff pollution,will retain the rain,and achieve the water cycle,thereby significantly reducing the surface runoff,so as to solve the problems facing the current urbanization.The study area located in the Yubei District of Liangjiang New District,it’s an area of 1.47 square kilometers.Construct the model of study area based on the the Uwater Drainage software.In order to get the goal of "the total runoff control rate reached 80%,the annual runoff pollution removal rate of more than 50%",we use low impact development technology,comparative analysis of the proportion of different LID layout plans,determine the optimal plan.After using the basic data to construct model of the current study area,under the 25.5mm design rainfall corresponding to 80% annual runoff,the drainage outlet total drainage volume was 13625m3,TSS,COD,TN,TP were 136.266 kg,79.034 kg,2.044 kg,and 0.095 kg.In order to determine the parameters of the LID in the combined LID scheme,three measures,namely the biological detention facility,the permeable pavement and the green roof,were simulated and analyzed respectively.The bioretention facilities,the permeable pavements and the green roofs in 2%,4%,6%,8%,10% of the area of layout ratio,relative to the status quo,the surface runoff peak reduction rate were 6.07%~96.40%,7.19%~64.27%,3.82%~40.90%;the total emissions reduction rate were 28.63%,~97.26%,31.77%~91.95%,12.62%~58.06%;pollutant reduction rate(in terms of TSS)were 28.71%,~97.35%,31.79%~92.15%,12.60%~58.33%。.For a single LID measure after the comparative analysis,the bioretention facilities,permeable pavement,green roofs all have certain control effect on runoff,and in the layout of a certain area ratio,all delayed the time of runoff peak.Under the condition of the same area ratio,the bioretention facilities integrated effect of runoff control was more significant than that of permeable pavement and green roof.Although the bioretention facilities significantly on runoff control effect,but from the results,when the area ratio increased,the control effect on runoff have no significantly increased,so a large-scale layout is not suitable,but the set scale of permeable pavement and green roof are more flexible.Considering the actual site,and from the total amount of annual runoff control rate,annual runoff pollution removal rate and economic perspective,two LID layout plans were analyzed and compared.Plan 1(bioretention facilities,permeable pavement,green roofs were accounted for 0.37,0.42,0.21),total annual runoff control rate reached 80%,the annual runoff pollution removal rate is 64.65%,the total investment cost of 71 million 222 thousand yuan.Plan 2(bioretention facilities,permeable pavement,green roofs were accounted for 0.23,0.34,0.43),total annual runoff control rate reached 80%,the annual runoff pollution removal rate is 63.25%,the total investment cost of 82 million 63 thousand and 200 yuan.Under the premise of satisfying the control target,the total investment cost of plan 1 is lower,so plan 1 is the best choice for the sponge city construction in the study area.