Analysis Of Urban Waterlogging Resilience Based On MIKE Model And Research On Optimization Of Waterlogging Prevention Measures

In recent years,with the rapid development of our country’s economy and the acceleration of urbanization,urban waterlogging disasters have become more frequent and more severe.The threat of waterlogging disasters to the safety of people’s lives and property has become more and more serious.The resilience analysis of urban waterlogging helps to understand the formation process and recovery ability of waterlogging disasters in essence,and provides scientific guidance for disaster prevention and mitigation and post-disaster recovery work of relevant departments.Based on the MIKE FLOOD model,this paper simulates the pipe network load and the inundation of surface water in Chaoyang New Town of Nanchang City under different rainfall periods,analyzes the resilience of the submergence of the study area,and studies the influencing factors of waterlogging resilience.Finally,according to the network load,stagnant water and waterlogging resilience value,it compares the waterlogging prevention and control effects of different schemes,the research results have important reference value for the construction of waterlogging prevention measures in the study area.The main results of this research are as follows:(1)This paper analyzes the pipe network load and water accumulation in the study area under rainfall in different return periods.The paper designs five return periods of rainfall,including 1a,3a,5a,10 a and 20 a,and selects 10 typical sub-catchments to analyze the rainfall and runoff conditions of the sub-catchments under different return periods.It can be seen that the comprehensive runoff coefficient and area Larger,the larger the total runoff and peak flow of the sub-catchment area.The number of overflow nodes and the proportion of overloaded pipelines in the study area increase with the increase of the rainfall return period.The proportions of overflow nodes and overloaded pipelines during the 1a rainfall return period are 9.59% and 17.16% respectively.It can be considered that the drainage capacity of the study area basically meets the standard of the 1a design return period.The analysis of the water accumulation in the study area shows that the lower the rainfall return period,the fewer the number of water accumulation grids,and the smaller the average water depth of the water accumulation area.(2)This paper analyzes the waterlogging resilience of the study area under different return periods of rainfall.Count the number of waterlogging grids in the simulation period,obtain the corresponding number of grids in the study area according to the set underlying surface inundation threshold,calculate the drainage system performance of the study area,and then perform elastic analysis of urban waterlogging.The results show that the smaller the rain return period,the smaller the maximum impact on system performance and the earlier the recovery time.The resilience analysis of waterlogging in the study area shows that the smaller the rainfall return period,the greater the minimum and final value of the waterlogging resilience value,and the smaller the total loss of system performance.Therefore,the better the ability to recover from waterlogging disasters,and the greater the return period of waterlogging.The change of the final value of the system resilience in the study area is more sensitive when it rains.(3)This paper studies the impact of the impervious rate of the underlying surface and the location of rain peaks on the resilience of urban waterlogging.The research results show that under three different scenarios of impervious coefficients of the underlying surface,the waterlogging resilience value decreases as the impervious coefficient of the underlying surface increases.The greater the impervious coefficient of the underlying surface,the greater the impact on the drainage system of the study area The greater the maximum impact of performance,the earlier the time to reach the maximum impact.However,the difference in waterlogging resilience under different rain peak position scenarios is very small.The more the rain peak position is,the lower the lowest value of waterlogging resilience,and the moment of maximum loss of system performance is reached earlier.(4)Based on the overflow node,the proportion of overloaded pipelines,the surface water accumulation and the waterlogging resilience value,the waterlogging prevention and control effects of four different gray-green schemes are compared.The results show that: Option 4(storm detention tank + green roof + sunken green belt + permeable pavement)with the most combination of measures has the best effect,while Option 1(storm detention tank + green roof)has a slightly weaker flood prevention effect than Option 4,Option 3(storm detention tank + permeable pavement)and Option 2(storm detention tank + sunken green belt)have similar effects.