Study On The Runoff Control Technology Of Impervious Surface In Green Building And Community

With the impact of human activities and the rapid development of urbanization, thecontradiction between supply and demand of water resources has become increasinglyprominent; the water pressure on the environment also increases. In recent years, a largenumber of urban green were replaced by impervious surfaces, causing the increase offlood peak flow. This caused great pressure on the drainage system, and caused thedeterioration of ecological environment, flood disaster, the decline of groundwater level.Low impact development is a source control management measure, which simulatesnatural hydrological condition through infiltration, filtration, evaporation and otherways. Low impact development makes hydrological characteristic unchanged, realizingrunoff decrease, pollution load reduction and protecting receiving water.Based on low impact development concepts, taking built-up areas in Shenzhen as acase study and different impervious surface rainwater as study objects, the paper usedrain test device for impervious surface hydraulic connection splitting to study rainwaterpurification in different combined condition. The main conclusions were as follows:â‘ The combined condition of road and roof rainwater could delay the runoffgeneration time of18-34minutes and runoff peak time of11-32minutes, which reducedrunoff volume of60.18%~65.07%. The runoff peak in combined treatment was0.61-0.99times of road rainwater and0.60-0.67times of roof rainwater. The pollutantconcentration of influent rainwater in road and roof gradually decayed with rainfallduration. The pollutant concentration of overflow rainwater in road and combinationpresented jagged fluctuation with rainfall duration.â‘¡The combined condition of square and roof rainwater could delay the runoffgeneration time of33-43minutes and runoff peak time of12-45minutes, which reducedrunoff volume of40.31%~87.92%. The runoff peak in combined treatment was0.44-1.09times of square rainwater and0.33-1.05times of roof rainwater. The pollutantconcentration of influent rainwater in square and roof gradually decayed with rainfallduration. The pollutant concentration of overflow rainwater in square and combinationpresented jagged fluctuation with rainfall duration.â‘¢By analysis of the effluent quality of overflow and osmotic, the device in twoconditions had certain removal effect on various pollutants. However, the removal ratehad a lager fluctuation. Without considering osmotic water, the device could cut various pollutants.The paper also studied storage and purification effect of the device. The resultsshowed that the device can receive0.80-1.02times impervious surface runoff of its ownarea in the return period of0.25years. With the increase of storage height or osmoticcoefficient, the device could receive more impervious area. In different return period,the device always could cut runoff pollution; however, the device would have a lowerdisposal during the increasing of return period.The study results can enrich research-based information of low impactdevelopment technology. It will offer technological support for low impact developmenttechnology and provide theoretical basis for city rain water utilization engineeringdesign.