郑州“7·20”极端降雨的城市内涝模拟及风险评估

Urban Waterlogging Simulation and Risk Assessment of″7·20″Extreme Rainfall in Zhengzhou

为科学认识和有效评估极端降雨对城市内涝风险的影响,构建了基于InfoWorks ICM的郑州市金水区老城区内涝模型,以郑州“7•20”极端降雨为例,评估了城市管道排水能力,模拟分析了城市内涝淹没情况,改进了英国基于行人安全的内涝风险评估公式中的部分参数。结果表明:郑州市金水区老城区58.54%的排水管道不能满足郑州市城市规划管理技术规定;在郑州“7•20”极端降雨中,排水能力较低的管道首先被充满,地面积水来时快、退时缓,最大满管率高达98.69%,发生时刻为当日18:00前后;由改进后的内涝风险等级评估方法计算可知,郑州市金水区老城区高风险以上区域占70.43%。该方法更适用于极端降雨下内涝风险等级的评估,可为城市极端降雨防控提供一定的技术参考。

In order to scientifically understand and effectively assess the impact of extreme rainfall on urban flooding risk,a comprehensive drainage model of the old city of Jinshui District in Zhengzhou City is constructed based on InfoWorks ICM.The drainage capacity of the pipeline is evaluated and the waterlogging inundation situation is simulated and analyzed under the″7•20″Extreme Rainfall in Zhengzhou.Some parameters of waterlogging risk assessment formula based on pedestrian safety in Britain are improved.The results show that:41.46%of the pipelines in the study area can meet the technical regulations of Zhengzhou City Planning and Management.During the extreme rainfall of″7•20″,the pipes with low drainage capacity were filled first,and the water on the ground was fast when it came and slow when it receded.The maximum rate of full pipes was as high as 98.69%,which occurred around 18:00 on the same day.From the calculation of the improved flooding risk level assessment method,it can be seen that the area above high risk in the study area accounts for 70.43%.The method is more applicable to the assessment of flooding risk level under extreme rainfall,which can provide some technical reference for urban extreme rainfall prevention and control.