Impacs Of Sponge-city Construction On Drainage System And Corresponding Design Methods In Chongqing

Recent years,the ‘sponge-city'(low impact development)construction has been adopted as a common patter for urban development and construction in China.Since its Yuelai New Urban Area being approved as state-level pilot area in 2015,Chongqing has been making a lot of efforts in promtoting sponge city development and practices.Application of sponge city measures and practices will have significant impacts on stormwater and wastewater collection system(sewerage system)in terms of runoff coefficient,time of concentration on land surface,and so on.Chongqing is a typical mountainous city with unique drainage characteristics,and how and what new sponge city measures and practices will have impacts on tradictional drainage design methods and pattern is worthy of study.Based on previous research outcomes on technology model of sponge city construction in Chongiqng main urban area,this paper is to make survey and analysis on present situation and problems of drainage system,traditional design methods and some sponge city design cases in Chongqing main urban area,find the impacts effects of sponge city on traditional drainage design methods,and propose the corresponding design.The main findings are as follows:(1)In combination with construction technology mode in Chongqing city,analysis in the sponge construction under the effect of separated drainage system ?The construction of chongqing sponge change the position and distance of road gully,sponge measures have the impact of regulation and storage on the stormwater runoff,and reduce the rainwater pipe diameter.Set the separated drainage system of catchpit,sponge measures can decrease the early rain intercepting and intercepting pollution load,decrease Sewage pipe diameter and the water and pollution load of sewage plant.(2)The influence of Chongqing sponge city construction on the new closure system,under the control of the same flow rate,the reduction of interception ratio and the reduction of influent of sewage treatment plant can reduce the pipe diameter and reduce the impact of sewage treatment plant operation.For built intercepting system,can reduce the CSO flow and volume in storage pool,the sponge measures can reduce the pollution load of the rain water,and it can also reduce the pollution load and.(3)Based on analyses on some parts of Yue Lai Xin Cheng of Chongqing,the existing land use,the existing situation and the sponge measures,this paper calculates the pipe diameter and the reservoir of the sponge city under the construction and the traditional mode.Finally the rainstorm management model SWMM software was used to simulate the traditional construction mode and the runoff condition under the sponge.The results show that the sponge measures controlled by the source can effectively reduce the peak flow rate,reduce the size of the pipe network,alleviate the urban waterlogging disaster.