The Application Research Of The XP-SWMM On The Rain And Flooding Simulation And Waterlogging Prevention In A City

Recently, with the rapidly increasing of the extremely rainstorms and continually deepening of city construction degree, use only experience formula to design the drainage system can't meet the demand of the outdoor plumbing code(2014 version). Setting up Water Management Model appropriately to assess the waterlogging in the research area can avoid eyeless drainage system design relied on experience.This essay chose the business software named XP-SWMM which is based on the classic SWMM to model a block in DY city,and used rate parameter set and stability test to define the undetermined parameters of this model : depression storage capacity impervious area is 2 mm, depression storage capacity permeable zone is 6.5 mm,Manning's impervious area is 0.0015, depression storage capacity permeable zone is 0.0375, Houghton formula decay constant is 2.5.We used XP-SWMM to simulate the rainfall runoff process under different storm return period and analyzed the risk of the block under different storm return period by using one and two dimensional functional module.It turned out that when the research area is under the P=1a~2a rainfall scene, it won't produce waterlogging point, when it is under the P=3a rainfall scene, there will be 14 waterlogging points, the most serious point of waterlogging flooding depth up to 1.750 m, when it is under the P=5a rainfall scene,there will be more than 1/2 node produce waterlogging phenomenon.We found out the bottleneck of status drainage network of the research area by simulation results analysis and set up the effective measures of waterlogging prevention including area pipe network transformation, setting rainwater storage tanks at the beginning and the intermediate network and LID pattern pavement permeable improve performance, etc. But the part pipe network transformation didn't have good effect on waterlogging mitigation. The regulating effect of setting rainwater storage tanks at the end of the network is not ideal compared to setting it at the beginning in the serious waterlogging research area.Though the trend of the simulation results of XP-SWMM's one-D and tow-D is consistent, the quantity of simulating waterlogging point may exist some deviation. During one-D simulation, it paid more attention on the ability to exclude the rainfall and rainout of the drainage system, it can find out the hydraulic parameters like network node, pipeline flow and velocity of flow intuitively. And two-D simulation provide a more intuitive way to find out the waterlogging region, waterlogging range, waterlogging formation and flood trend.