Urban Storm System Construction And Efficiency Evaluation Based On Sponge City Concept

Under the traditional construction mode,the urban rainwater system is mainly composed of simple facilities such as rainwater outlets,pipe channels and pumping stations.The main task of the rainwater system is to quickly discharge rainwater to prevent flooding in the city.The shortcoming is that it does not consider flooding problems in downstream receiving water bodies and areas along the pipe line,nor does it consider the purification and utilization of rainwater.The construction of the sponge city puts forward new requirements for the traditional rainwater system,and it is necessary to consider the infiltration,retention,collection,purification,utilization and discharge of rainwater.Due to the short time for China to promote the construction of sponge city,there are few research reports on the construction mode of urban rainwater system under the current construction mode of sponge city.Therefore,this paper first studies the potential of sponge function expansion in traditional rainwater systems.Then,based on the sponge technology that can be applied based on the expansion potential,propose a sponge urban rainwater system construction model.Finally,the effectiveness evaluation was carried out using SWMM(Storm Water Management Model).main tasks as follows:This paper studies the potential of sponge function expansion for traditional rainwater systems.The unit of the traditional rainwater system that can expand the sponge function was studied.The external influence conditions of spon ge function expansion were studied in Shenzhen.The results are as follows: In addition to rainwater discharge,the gully can also increase rainfall infiltration and retention function;inspection wells can increase rainfall infiltration,retention,and storage functions;pump stations can increase rainwater retention and collection in addition to rainwater discharge.Function;the discharge port can increase the function of rainwater purification.Shenzhen water removal capacity needs to be improved,to meet the conditions of rainwater infiltration,retention,utilization and discharge.This paper has carried out technical research on the sponge potential of traditional rainwater systems.Analyze the problems and solutions to achieve the sponge function,The results are as follows: the permeable area and the infiltration rate affect the rainwater infiltration,the roughness and slope of the catchment surface affect the rainwater retention,the storage capacity affects the rainwater harvesting,the purification link and the purification capacity affect the rainwater purification,the water volume and water quality affect the rainwater utilization,and the discharge Capacity and quantity of water affect storm water emissions.The sponge potential can be achieved by the traditional rainwater system’s own excavation and external environment matching.A sponge urban rainwater system construction model consisting of environmentally-friendly rainwater nozzles,permeable water pipes,permeable inspection wells,storage tanks,and discharge ports with garbage isolation nets was proposed.Based on the above research results,the G area of Shenzhen City was taken as the research object,and the SWMM model of the traditional rainwater system,the sponge transformation and sponge modification combined with sponge urban rainwater system in the study area was established to evaluate the efficiency of the rainwater system.The results show that: Sponge City can reduce the discharge of rainwater pipe network,Delay the occurrence of flood peaks,reduce the flood peak flow,reduce the amount of surface erosion pollutants(Based on the indicator of SS),and improve the overflow of pipe network nodes.These abilities decrease as the return period of rainfall increases.The combinati on of the sponge modification and the sponge urban rainwater system is superior to the sponge modification alone.