Evaluation Of Urban Waterlogging Resilience At Different Spatial Scales In Haikou City

In recent years,natural disasters occur frequently in cities,and waterlogging disaster has become one of the biggest threats facing cities.In the face of increasingly severe urban waterlogging disasters,improving urban resilience is a new way to achieve future urban development.Based on the review of the relevant literature on urban resilience and waterlogging disaster risk,and the theory of urban resilience and disasters,this paper proposes the process decomposition of urban resilience from the perspective of "pressure-state-response",which penetrate the whole process of "predisaster-in-disaster-post-disaster" of waterlogging disasters.Taking Haikou City as the research object and combining it with cloud model theory,the urban waterlogging resilience of Haikou City was analyzed and evaluated from the perspective of different spatial scales.According to different stages of urban waterlogging,corresponding optimization measures are proposed,and the research results are as follows:(1)Sorting out and summarizing relevant theories and methods of existing urban resilience and waterlogging simulation models,screening numerous domestic and foreign resilience assessment methods,and selecting a combination of various methods to carry out assessment of waterlogging resilience in the study area from the city and area scale.An urban-scale waterlogging resilience evaluation system was constructed based on the game theory combination weighting method,and the grade distribution of waterlogging resilience in Haikou City was evaluated by combining the cloud model comprehensive evaluation method.The results show that the overall resilience of Haikou city in 2015 and 2020 is at a medium level,with a slight decline trend over time,down by 2.35%,and the state resilience shows a sharp decline trend,down by 13.15%.(2)Longkungou Area was taken as a regional-scale research area,and the urban waterlogging resilience was evaluated by using scenario simulation method.SWMM and PCSWMM were selected to construct a simulation model of urban waterlogging in the study area.The model has high reliability after calibration verification.Five rainfall scenarios with recurrence periods were selected for simulation calculation,and the results showed that the pipe network load and node overflow ratio reached83% and 64% respectively under the once-in-50-year rainfall scenario.(3)To simulate the inundation of waterlogging in Longkungou area under the design rainfall scenario of once in 50 years,and establish an evaluation index system of waterlogging resilience at the regional scale.The evaluation results show that the main indexes of waterlogging resilience level in the study area are inundation depth and inundation duration.The areas with low toughness are concentrated in the flat terrain of the lower reaches of Longkungou and Daokegou,while the areas with high resilience are distributed in the southern part of the area away from the river.(4)Strategies for improving waterlogging resilience at different scales in cities are put forward.On the basis of the resilience assessment results,optimization measures are proposed for the resilience,recovery and adaptability of cities facing waterlogging disasters,so as to alleviate the losses caused by waterlogging and further improve the overall resilience of cities.