Urban Waterlogging Simulation And Optimization Based On MIKE URBAN

In view of the frequent urban waterlogging problems in China,this paper takes an old town in Tianxin District of Changsha City as an example,collect the topographic data of the area and the geophysical map of the current pipeline network,built the urban pipe network model by Mike Urban software,simulate the current pipe network model under rainfall conditions of different return periods and analyze the drainage capacity and the overflow of the current pipe network in this area.In addition,based on the current pipe network system in this area,three optimization schemes of waterlogging prevention and control are designed,and the effects and economic benefits of the three schemes are compared and analyzed.The main research conclusions are as follows:(1)In this paper,Mike Urban software was used to establish the current pipe network model,and the hydraulic parameters of the pipe network model were calibrated by runoff coefficient comparison method.The errors met the requirements,which proved that the accuracy of this model establishment met the requirements and had certain reliability,which could be used for subsequent studies.(2)In this paper,the status quo of pipeline network under different return period for hydraulic simulation,with the increase of return period,node and pipeline have gradually increase in the number of overflow,under the condition of the return period of 2 years of rain,the node the overflow ratio is 17.29%,flow capacity is 16408 m3,the return period of 50 years rainfall condition,the node overflow ratio reached 43.61%,flow capacity increased to 78243 m3.Through the analysis of the drainage capacity of the current pipeline network,the length of the pipeline with a design return period less than 2 years is 19,588.3m,accounting for 67.25%,indicating that the drainage capacity of the current pipeline network in the study area is low and fails to meet the standard of once-in-50-year waterlogging prevention.(3)In view of the overflow situation in the study area under the rainfall condition of 50 a return period,three different waterlogging prevention and control schemes are set up,namely LID facility scheme,storage pool scheme and the combined scheme of LID facility and storage pool.Compared with the simulation results,it is concluded that the control effect of the storage pool scheme is the best,and the peak flow of the outlet is significantly reduced.In terms of the control effect of regional overflow,the reduction rate of overflow flow of LID scheme is 38.13%,and the reduction rate of overflow flow of both the storage pool scheme and the combined scheme are more than 90%,showing significant reduction effect.In terms of investment cost,the LID scheme invests 284.467 million yuan,the storage pool scheme has the lowest investment of 218.92 million yuan,and the combined scheme has the highest investment of 413.167 million yuan.To sum up,the storage pool scheme is the preferred solution to the waterlogging problem in the short term.The combined scheme combines LID facilities and the storage pond,which not only solves the waterlogging problem,but also brings various environmental and social benefits.Although the investment is relatively high,the combined scheme is the best one in the long run.