Research On Adaptability Of Sponge City Construction Technology Based On SWMM Model

Over the past three years,with the country's attention to urban waterlogging and water environment problems,a series of policies on urban waterlogging management and environmental protection and management,such as sponge city construction,have been introduced.Sponge city construction pilot cities from north to south,from east to west,pilot cities of hydrological basic conditions are not the same,such as rainfall conditions,soil permeability,groundwater level,resulting in urban construction after the effect is not ideal.Therefore,this paper mainly chooses the SWMM model developed by the US Environmental Protection Agency and the general situation of Shenzhen city planning and construction and the hydrological foundation to study the adaptability of Shenzhen sponge city construction.Based on the analysis of the functional types and influencing factors of sponge technology,this paper analyzes the topography,groundwater level,soil permeability,urban surface,urban non-point source pollution and rainfall in Shenzhen,and selects the single rainwater garden.Pavement and green roof measures as the object of study.The model of SWMM model was established in Shenzhen Meiyu Area as the research area.The actual rainfall of the study area was introduced into the model,and the effects of rainwater runoff on the runoff and the effect of sponge control were simulated.Through research,we get the following works:(1)The runoff coefficient of the study area increases with the increase of the terrain slope.The total runoff and runoff peak in the untapped state,both in the Keifei & Chu rain and the measured rainfall,are higher than those in the conventional development Which is small and has a large change in runoff flow rate in the normal open state.(2)The total runoff and runoff peak of undeveloped state increase with the increase of the reproduction period.The peak value of the runoff is mainly due to the strong soil permeability in the undeveloped state and the natural litter and plant The retention and retention of rainwater;(3)The effect of reproducibility on the runoff of pollutants is small,and the pollutant runoff is mainly affected by the rainfall intensity.The larger the initial rainfall intensity is,the stronger the scouring ability is,and the larger the pollutant concentration is.(4)The total runoff and runoff peak produced in the non-uniform rain form are more than 2 times higher than that produced under the uniform rain condition.Therefore,the uniform rain type is not suitable as the rain design in the engineering practice,but the typical rainfall type should be adopted.The total amount of pollutants SS,COD,TN and TP produced by uniform rain is less than the total amount of contaminants produced by nonuniform rain.(5)measured in 2 years and 10 years under the conditions of rainfall,rain water garden,pavement and green roof runoff reduction effect is very obvious,the proportion of runoff reduction of more than 30%,while the rain garden in 10 years The effect of controlling rainwater runoff under the rainfall condition is more obvious;(6)The total effect of SS,COD,TN and TP in rainwater garden,pavement and green roof is obvious.Meiao12 and Meiao18 catchment area,rainwater garden,pavement pavement,Green roof three measures on the pollutants SS,COD reduction percentage were 50% or more and 30% or more;...