Research On Evaluation And Simulation Of Rainwater Control And Utilization Effect In Building Community Based On SWMM

In recent years,the rapid development of China’s urban construction,the use of a large number of impervious ground water,resulting in the gradual reduction of groundwater supply,in the increasingly strained water resources today,resulting in unnecessary waste.At the same time,impervious ground greatly improves the speed of rainwater confluence,resulting in the characteristics of "early flood peak,large runoff and high peak" in the city during rainfall.In addition,the infrastructure is not perfect,resulting in the dilemma of "looking at the sea" in the city,which seriously affects the normal operation of the city.Impervious ground is prone to accumulate pollutants,which are collected into the receiving water body through runoff,causing non-point source pollution and seriously endangering the urban water environment.Low-impact development adopts source control management,simulates natural hydrological conditions by means of infiltration,detention and filtration,and does not affect the hydrological characteristics of the development area,so as to achieve the goal of reducing runoff,reducing runoff pollution load and protecting the receiving water body.This article through to J urban conditions,weather conditions,topography,geology hydrology,drainage pipe network and urban flood control information collection analysis and the measured rainfall and rainwater runoff pollution situation in J city,studies the characteristics of the rainwater pipe network and the urban flood control and stormwater runoff pollutants scour law,showed that COD,SS,TN,TP has a good correlation between four kinds of pollutants,the correlation coefficient between 0.82 ~ 0.98.At the same time,taking a certain building community S community in J city as an example,the water quality and water quantity monitoring are combined with the model simulation to optimize the hydro-hydraulic and water quality parameters of the model and test the applicability of the analysis model,and the research regional model is established.Based on the discharge volume at the outlet of the research area and monitoring data of pollutant SS,the established SWMM model was calibrated and verified.The model simulation value and the monitored NSE were both greater than 0.5,and the simulation effect was good,which could reflect the runoff and pollutant change process during rainfall in the research area.According to the rate after the model of low impact development facilities,water depth and different return period,under the condition of rainfall simulation study area low impact development mode of rainwater control effect,show that with the increase of rainfall return period,within the study area is low impact development measures to the control effect of runoff amount and SS output load gradually reduce,in the case of sinking depth of 200 mm,reduced by 6.18% and 7.08%,respectively,in the case of sinking depth of 300 mm,reduced by 4.51% and 5.83%,respectively,provide theoretical support for building drainage system of the low impact development.