| In recent years,due to the increased impervious surface of urban development,rainwater quickly converges to the pipe network.In extreme weather,it will increase the hydraulic load of the rainwater pipe network and cause overflow,which will cause urban waterlogging.Urban waterlogging disasters not only affect traffic safety,destroy public property,but also threaten people’s lives and health,causing huge economic losses.At present,there are few research results on the application model for simulating urban waterlogging and waterlogging areas and the runoff change process of the drainage pipe network system,and the application is insufficient.Aiming at the increasingly prominent urban waterlogging problem,this paper selects Certain district of Handan City to establish SWMM(Storm Water Management Model)model.Based on the measured rainfall,the modified Morris screening method was used to analyze the sensitivity of the parameters.The runoff coefficient method was used to verify and verify the model parameters in the design storm scenario.Finally,the model was calibrated to simulate the surface of the study area under different rainfall periods Runoff,pipe section overload,node overflow,discharge outlet runoff change rules,analysis of waterlogging and waterlogging locations,waterlogging depth,and assessment of the current rainwater system drainage capacity.The main research results are as follows:1.The SWMM model of the study area was quickly established by using ArcGIS software and inp file editing functions.The model included a total of 224 subcatchments,249 nodes,and 250 pipe sections.2.Sensitive analysis of parameters based on the modified Morris screening method.The results show that the parameters with significant sensitivity are Destore-Imperv,Roughness,and N-Imperv,but the coefficients of variation of these parameters are small,so they can be considered as relatively stable parameters in the SWMM model.3.The runoff coefficient method was used to verify and calibrate the model parameters,and the coefficients of variation of the parameters under different recurrence periods were 3.73%,3.02%,5.54%,7.72%,and 10.33%.Parameters can be used for waterlogging simulation in the study area.4.With the increase of the recurrence period,the surface runoff gradually increases,the overload of the pipe section,the overflow of the nodes,and the range of the water accumulation area gradually increase.The overload and overflow time continue to prolong,the discharge caliber and the peak of the runoff gradually increase,and the flood peak appears.The time also gradually advanced.When the recurrence period is 0.5 years,1 year,2 years,3 years,5 years,and 10 years,the overload rate of the pipe section is 0%,18%,45.6%,67.2%,68%,69.6%,and the node overflows.The flow rates were 0%,10.4%,25.1%,35.15%,44.35%,and 52.72%.In the case of 1 year,2 years,3 years,5 years,and 10 years,the runoff at the discharge port 2 increased by69.16%,77.16%,81.99%,84.95%,89.45%,and the peak runoff was 0.5 compared with the case at 0.5 years.It is 1.10 times,1.12 times,1.16 times,1.19 times,and 1.22 times in the case of the annual event,and the Hongfeng moment is 4min,5min,6min,8min,and 10 min earlier than the 0.5 year event.5.ArcGIS software was used to spatially display the water accumulation position of the location,water accumulation range,water accumulation,and water accumulation depth of the study area,and select the node section map of a certain road section and the pipe map of the study area to display dynamically at different times.In terms of space,the study area has high imperviousness in the northwest and high rainwater flow in the southeast.Therefore,rainwater partitions 1 and 3 are prone to accumulate water,and partition 2 is better.The node and pipe network dynamic graphs show that the number of pipe sections overloaded and node overflows increase after the peak rainfall,and as the duration of rainfall increases,the pipe sections in lower terrain will be overloaded and node overflows will continue for some time. |
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