Simulation Evaluation On Rainwater Control Measures Of Sponge Community Based On SWMM Model

The paper selects a community in Haidian District,Beijing as the research object.By constructing a SWMM model and setting LID measures,the model simulates the reduction of runoff,nodes and several common pollutants in the area before and after the LID measures are built in the community to select from Determine the optimal storm flood measures plan to provide reference for the development of LID measures in the community.During the research process,the nodes,pipelines,catchment area and other related parameters of the study area were collected through investigation and data collection,and the drainage system and catchment area of the community were generalized using the SWMM model.The study area is generalized into 129 subcatchments,24 nodes,24 pipe sections and 1 discharge outlet.Through the Chicago rain pattern generator,combined with the Beijing rainstorm intensity formula,the design rainfall data with four return periods of P=3,P=5,P=10,and P=20 years are calculated.At the same time,based on the actual situation of the community,three schemes were set up.After comparing the above three LID measures from four aspects: hydrological effect,pipe network effect,water quality effect,and cost-effectiveness,the most suitable LID measure plan was selected for deployment in urban communities.After simulation,the second recommended option is the optimal one.The specific measures are 2,533 m2 rain garden,2,310 m2 permeable paving,and 4882 m2 green roof.Combined with the model simulation,after implementing the LID measures of the second plan,the effect of the area in terms of water volume and water quality,the research results show that in terms of water volume reduction,compared with the LID measures before the construction,the flood reduction rates after construction are: P =3,39.6%,P=5,37.4%,P=10,35.9%,and P=20,35%.In terms of hydraulic power,compared with before the construction of the LID measures,the overload reduction rate of the rainwater pipe network after the construction is 100% when P=3,80% when P=5,50% when P=10,and P=20.In terms of water quality control,four common pollutants,SS,COD,TN,and TP,are used as the research objects.The total removal rate of various pollutants and the single pollutant removal rate before and after LID measures under different rainfall return periods Comparing the concentration process line of the discharge outlet,it is found that the second scheme in this paper can effectively reduce the total amount of pollutants.The construction cost of this scheme is 3.2 million yuan,and the annual maintenance cost is 400,000 yuan.The thesis simulates and evaluates the effect of different LID measures in the construction of the community on the reduction of rainfall runoff and pollutants.The research results have a guiding role in the development of rainwater utilization in urban communities,prevention and control of urban waterlogging,and have important reference significance for the construction of sponge cities in my country.