| In recent years,the frequent occurrence of rainstorms and floods has caused huge losses to social and economic production.Frequent urban floods have brought severe challenges to the steady construction and healthy development of a harmonious society.In order to cope with the changing climate environment and reduce the impact of flood disasters,this paper takes Zhengzhou City as an example,relying on the "Research on the Theory and Method of Urban Flood Disaster Prediction and Early Warning Based on Big Data"(51739009)National Natural Science Key Fund Project,using the trend mutation test.The spatial and temporal distribution characteristics of rainfall and the characteristics of rainfall patterns in the central urban area of Zhengzhou were analyzed by the method and spatial interpolation method.A set of cost-benefit comprehensive evaluation system of waterlogging disaster prevention and control measures was constructed with regret decision theory.The research results are of great significance for in-depth understanding of the response law of urban waterlogging and rainfall patterns,and the comprehensive evaluation method of urban waterlogging disaster prevention and control measures.The main research results are as follows:(1)Analysis of the temporal and spatial evolution of rainfall: Statistics on the rainfall data of meteorological stations and rainfall stations in the central urban area of Zhengzhou are carried out,and the Mann-Kenda trend test method is used to analyze the trend mutation of the rainfall evolution laws,and it is found that the annual rainfall of meteorological stations and rainfall stations The changes all showed different degrees of growth trends and there were sudden changes in 1978,1990 and 2007.Based on the kriging interpolation method and the inverse distance weight method,the spatial distribution of rainfall is explored,and it is found that the inverse distance weight method is more suitable for the study of the spatial distribution of rainfall in this area.There is relatively little precipitation in the northwest.(2)Analysis of rainfall pattern characteristics: Rain pattern differences can be divided into differences in the number of rain peaks and the location of rain peaks.According to the different number of rain peaks,the common rainfall types in the central urban area of Zhengzhou are counted,and the results show that the rainfall in this area is mostly unimodal,followed by bimodal rainfall.There is a certain difference in the rain peak location coefficient in each rainfall process.Based on the measured rainfall data and the waterlogging inundation data of the web crawler,the gray correlation method is used to find that the rain peak location coefficient is highly correlated with urban waterlogging.(3)Analysis of the response of urban waterlogging to rain patterns: For the selected southern part of Jinshui District as a local study area,the designed rainfall process was given in combination with the characteristics of rain patterns,and an urban waterlogging coupling model was established based on MIKE software,and the waterlogging scenarios were deduced from Quantitative analysis of the response law of rain pattern and waterlogging was carried out in three aspects: total inundation,inundation spatial distribution and inundation depth.The results show that among the three types of rain,the inundation caused by the double-peak rainfall is the most serious;for the single-peak rainfall,when the rainfall return period is less than 20 a,the higher the rainfall peak is,the more serious the inundation is.The more serious,when the rainfall return period is higher than 20 a,the more serious the inundation is caused by the further back of the rain peak.The peak inundation area caused by the three types of rainfall all increased with the increase of the return period,and the increasing trend was gradually slow.Most of the submerged depths caused by bimodal rainfall are higher than those caused by unimodal rainfall,and there are certain differences in the distribution of submerged depths of the two unimodal rainfalls according to different return periods.(4)Evaluation of urban waterlogging disaster prevention and control measures:Comprehensively considering the hydrological effects of rainwater management measures,combined with the whole life cycle cost method,the analytic hierarchy process and the regret decision theory,a comprehensive cost-benefit evaluation system was constructed.The results show that different rainwater management measures have different prevention and control effects on urban waterlogging disasters,and the combined measures have stronger runoff control effects than single measures.The combination of sunken green space + permeable pavement +green roof shows the best runoff control ability,and the highest runoff control rate can reach 61.97%.Through the visual analysis of urban waterlogging risk,it can be seen that the implementation of rainwater management measures can alleviate the risk of urban waterlogging,and the maximum reduction rate of overflow nodes is72.15%,but these measures are still not enough to completely eliminate the risk of waterlogging.Comprehensive evaluation of the performance of different stormwater management measures in terms of hydrological effect,economy,environment and operation,the combined measure of sunken green space + permeable pavement +green roof has a comprehensive regret value of 0.21,the lowest regret value,and is determined to be a sponge city The most cost-effective solution in construction. |
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