Application Research Of Rainwater System Modeling Based On SWMM Platform

Water is the lifeline of the development of a city and even a country.In recent years,after a rainstorm in summer,the phenomenon of "inland watching the sea" can be seen everywhere,therefore,the media and the public generally turn their attention to the municipal pipe network,.Even though the government invested a lot of financial resources in the underground pipe network reconstruction,repair,widening and so on,the effect was not obvious,and the phenomenon of "road rowing" still existed.Nowadays,the water logging problem is not just a problem of the layout of the underground pipe network,it is related to the ecological problems of a city development process and to the ecological problems in the process of urban development.As for the city as a complex ecosystem,the proposition of "sponge city" is undoubtedly a milestone for the construction of ecological balance in China.SWMM is a rainfall runoff storm management model based on water power,and can simulate water quality.For some common LID measures,SWMM can also run successfully.The key to the accuracy of the model is the rate of parameters.In this paper,the rainfall in QD city is measured with the SWMM model as the background,and then the parameter rate is determined.Preliminary analysis of the local sensitivity of hydrological water quality was carried out by perturbation analysis method in the SWMM model.The analysis results show that the SWMM model under QD rainfall,hydrological and hydraulic N-imperv of maximum peak flow model sensitivity,followed by Des-perv;water quality to the accumulation of COD as a standard,the most sensitive to the COD concentration was road Max buildup,followed by road rate constant..After the completion of the SWMM model,the network overload phenomenon is compared between the present model and the conventional development model under different recurrence periods p=1a?3a?5a?10a,the results show that the conventional model is 0%,20%,25% and 20% higher than the overload point of the present model,and the conventional model is increased by 0%,20%,28.6% and 37.5%.,respectively,compared with the present model.In order to solve the network overload problem,research on the regional model were performed to optimize the network,switching shunt,add reservoir,change the pipe shape(optimization design using IRREGULAR module in SWMM drainage pipeline section)measures,4 measures can effectively control for network overload.For the water quality of regional rainfall,LID measures are added to the SWMM model,which are: filter belt,seepage channel and green roof.Among them,the decrease of runoff is most significant,and the control effect of green roof on pollutant is the best.In order to ensure the low impact development of LID measures and the combination of the economic benefits of the rain pipe network,the PSO particle swarm optimization algorithm is used to optimize the combination,and finally get the optimal results of the LID measures of low impact development in the study area.Study on the content of domestic small and medium-sized city especially provides new technical support to flood drainage in QD City,for the construction of the city with sponge a force.