Study On Urban Waterlogging Risk Assessment And Sponge Measures Reduction Control Effect

With the continuous advance of urbanization,the urban hydrological environment has undergone great changes,and the situation of waterlogging management are facing new challenges.In recent years,non-engineering and engineering measures have been combined to play an important role together in the field of urban waterlogging control.The waterlogging research method based on scenario simulation is also increasingly favored by researchers.This paper takes Cangshan District of Fuzhou City as the research object,systematically studies and summarizes the key issues and relevant experiences in the process of building urban waterlogging model,and establishes the urban comprehensive drainage model of Cangshan District.The main research achievements are as follows:(1)Based on quality inspection and generalized pipeline network data and hydrology,topography and other basic data,the urban waterlogging model of Cangshan District was constructed using ICM,and the parameters of the model were calibrated and verified using four measured rainfalls.The influence of the model structure on the model results is explored.The results show that the larger the grid,the greater the error,and more precise gridding of the waterlogged areas alone can effectively improve the simulation accuracy;the lower the land use accuracy,the lower the runoff;The lower accuracy of elevation model will result in increased water depth simulation results but have less impact on the results of node overflow and pipeline overload results.After the pipe network is generalized,the total overflow volume under the first-level generalization increases and the main pipe network overflow volume decreases.The amount of overflow in the main pipeline network under the second-level of generalization increased.(2)Using the rainstorm intensity formula of Fuzhou City and the Chicago rain pattern,nine kinds of rainfall scenarios with different return periods were designed,and the node overflow and pipeline operation status and surface submergence of the main pipeline network in Cangshan District under different rainfall return periods were simulated.The simulation results show that the flooded area,flooding nodes,and the number of pipelineoverloads all increase continuously as the rainfall return period increases.The analysis of the drainage capacity of key areas shows that the main problems in the current drainage situation are: Poor drainage due to low terrain,and fewer trunk pipelines in some areas cause the service area to be too large which result in increased drainage pressure.(3)The flood depth&duration method and the modified HR threshold method were used to evaluate the waterlogging risk in Cangshan District.Based on the domestic mature construction damage curve combined with the actual situation of Fuzhou city to assess the unit area and total disaster loss.The results show that with the increase of rainfall return period,the waterlogging risk and losses continue to increase.The reduction and control effects of single and combined sponge measures were studied,and suggestions for the arrangement of sponge measures were proposed.