Optimizations Of Flood Preventions And Drainage Plan Study Based On Sponge City Construction

Recently years,Most cities have occurred flood disaster in China,which included some merge cities such as Beijing and Nanjing.Flood disaster could submerge roads and roofs,as a result it brings the great negative effect to traffic condition and life of urban residents.the rapid development of urbanization leads to relatively high impervious rate in cities,while the design standard of urban rainwater drainage system is relatively low,causing the rainstorm waterlogging when the urban pluvial flooding hits the city.The paper focus on the solution of urban pluvial flooding and reestablishes the urban rainwater drainage system by utilizing the concept of sponge city,the low impact development(LID)is also utilized to increase the rain runoff infiltration,store rainwater resources,reduce storm water runoff,mitigate flood and waterlog disaster.The main works of the paper are:(1)Research on the way of urban storm water management in the world is analyzed by using the present situation to study the management problems.the paper is formed in four aspects,which are traditional storm water management system,city water system,urban green space system and construction area.The present situation of all aspects is analyzed.The research shows that urban storm water management should pay attention to the combination of infrastructures of “gray” and “green”.Green infrastructure reduces the rain runoff flow by trapping,infiltrating and purifying and then gray infrastructure drains rainwater to city water system rapidly,which solves the urban flooding effectively.(2)Content development and technology roadmap of low impact development(LID)in urban rainwater system are probed.By referring to document literature and case studying,the paper concludes that low impact development(LID)is applicable to city rain water program.Flood control and drainage should follow the principles of ecology environment and city water system designs taking low impact development(LID)in account.By researching the concept,advantage and applicable situation of low impact development(LID)single measures,the paper concludes that: green roofs,permeable pavement,biological stranded measures,sunken greenbelt,infiltration ponds,pits,wet ponds,rainwater wetland,dry grass swale are applicable to city Flood control and drainage but those measures should also be related to others organically according to the actual site conditions.(3)Taking the flood control and drainage of Panji as examples,the paper puts forward the urban rainwater utilization planning of Panji according to the actual situationand related principles.Taking the fact that the land use plannings of Panji are mainly the residential lands into consideration,the paper designs the low impact development(LID)system of 1#,2# residential buildings combing with the actual situation.The paper also designs the system of multi-stage ponds and ecological river regulation according to the city water system.The appropriate pipe-diameters are calculated by the parameters such as the runoff coefficient and the rainstorm flow and the pipes are laid along road with the help of the traditional urban storm sewer system.Finally,the paper forms a flood control and drainage system by combing “gray”with”green”organically.The research on the control rate of runoff volume shows that when the return period is 1 year,the rate is 53.5%.Furthermore,by accounting the pipe diameters of some pipes,the paper finds out that the pipes’ diameters are less than those of the traditional pipes,which means it can lower the costs of the networks.