Study On The Effect Of Rain-flood Controlbased On SWMM LID Measures

In recent years,with China’s rapid economic development and urbanization ofthe city vigorously promote,the impact of human activities on the natural environment is more and more big,a lot of the original nature of pervious surface by building,square,parking lot and other impervious surface replaced the original rainfall runoff confluence-flow process is changed,a lot of rain unable to penetrate into the ground leads to the increase of surface runoff,causing waterlogging disasters.In order to reduce and alleviate the urban waterlogging caused by rainfall and runoff,people began to change the traditional development mode and adopt a more natural development mode.Therefore,the state put forward the requirement of building an eco-friendly society.With the deepening of research,the Low Impact Development(LID)measures have gradually entered the line of sight.More and more areas combine the LID measures with the urban reconstruction and new construction in order to achieve the purpose of building an eco friendly society.This paper takes City Industrial Park in Yunnan Province as a sample,using SWMM model,control effect analysis and comparison of 3 kinds of LID measures on flood in different rainfall scenarios,and sensitivity analysis to select sensitive parameters by changing the parameter sensitive analog control effect in the case of different underlying surface under the analysis and comparison of green roofs,and sunken pavement permeability the green of the 3 LID measures on flood,in order to provide theoretical basis for selection of city LID measures.The simulation results show that:(1)The results show that,when the rainfall is small,the reduction rate of the total surface runoff and the flood peak flow rate is the largest in the lower concave green space.When the rainfall is large,the reduction rate of the total surface runoff and the flood peak flow rate of the LID is not ideal.And the lower concave green space has the best effect on the delay of the peak time.(2)When the rainfall increases,the reduction rate of the total surface runoff is the largest in the lower concave green space,and the cutting rate of the permeable paving for the Duan Hongfeng flow is the largest.And the reduction rate of the total surface runoff and the flood peak flow of the 3 LID measures will increase with theincrease of rainfall duration.And the effect of percolation on the delay of flood peak time is best.(3)When the location coefficient of rainfall peak changes,the total reduction rate of surface runoff,the reduction rate of peak discharge and the delay effect on peak flood time will not change.In this case,the effect of permeable pavement on the peak discharge of pipe section,the reduction rate of peak discharge of pipe section and the delay effect of pipeline peak flood time are all better than those of the other two measures.(4)Using modified Morris to select sensitive parameters and changing the sensitive parameter values to simulate different underlying surfaces,repeat the above steps and get the same conclusion.Therefore,it is generalized to judge the above conclusion.(5)Through the cost-benefit analysis,it is concluded that the cost and benefit of No.101 is the highest,but more funds should be invested if we want to achieve better control effect.