Simulation Of Low Impact Development And Pipe Network Optimization Based On SWMM

With the rapid development of urbanization,the influence of urban rain and flood has aroused widespread concern in the multidisciplinary field.The simulation and management technology of urban rain and flood has entered a new stage of development,and faces many challenges and opportunities.The main research contents include:(1)Based on SWMM,the urban stormwater flood model in the study area has been established,and the hydrological effect of urbanization has been quantitatively assessed.According to the simulation results,the runoff of 50 years and a heavy rain is 4.7 times as high as the natural state,and the runoff of 0.5 years of rain is 11.8 times as high as that of natural state.This indicates that urbanization will lead to an increase in runoff compared with natural conditions,and urbanization is more sensitive to rainfall events with a smaller recurrence period.(2)Aiming at the high frequency design of rainfall,this paper simulated and analyzed the hydrological effect of 6 kinds of LID measures,designed the LID optimization layout of the study area,and finally selected the "rainwater garden + permeable paving" combination of LID measures,which were all excellent in all the control indexes,as the optimal layout method.(3)In view of the low frequency design of rainfall,combined with the above LID measures,the optimization scheme of the pipeline network under the low frequency design rainfall is put forward,which can improve the abuses of the low drainage capacity of the original city pipe network while giving full play to the "seepage,the storage,the net and the use" of the low impact development measures.On the basis of the depth of node water accumulation,the time of overloading of nodes and the overloading time of the pipe section,the bottleneck of the pipe section and the node is identified,and the pipe network transformation scheme to change the height of the bottleneck node and to increase the pipe diameter of the bottleneck is proposed,and the simulation results prove that the optimization scheme is feasible.