芝加哥雨型与城市灾害性降水的比较研究

Comparative study on Chicago rainstorm pattern and urban disastrous precipitation

目前城市洪涝研究中较多采用以芝加哥雨型为主的设计降水作为输入,该方法存在一定概化,实际防洪排涝应用和水文过程研究中需要进一步探索芝加哥雨型法表征灾害性降水存在的相关问题和缺陷。以郑州市城区2011~2018年发生的致灾降水事件为研究对象,总结了致灾降水的年内演变趋势;比较了芝加哥雨型设计降水与致灾降水峰值分布、强度等过程信息;基于雨洪模型(SWMM)分析了研究区不同成因的城市洪涝过程发生发展的差异,并与芝加哥雨型法输入的雨洪过程进行比照。结果表明:(1)郑州市城区年内致灾降水存在从雨强致灾发展为双致灾,再过渡到雨量致灾的趋势;(2)研究区2 a一遇芝加哥雨型洪涝过程与雨量致灾降水近似,5 a一遇及更高标准的芝加哥雨型具有双致灾降水的洪涝特征;(3)雨强致灾所致的洪涝过程积水历时短、程度小,雨量致灾洪涝过程持续时间长,双致灾洪涝过程兼具雨强、雨量致灾机理,影响范围更广。研究结果对城市内涝防治、海绵城市建设和地区防涝减灾具有一定意义和参考价值。

At present,design precipitation especially Chicago rainstorm pattern,has been widely used as the input in current urban flooding researches.Due to the generalization of this method,in the actual flood control applications and urban hydrological processes research,it is necessary to further explore the related problems and defects when using Chicago rainstorm pattern to characterize disastrous precipitation.Based on the flood-causing precipitation events that occurred in Zhengzhou City from 2011 to 2018,this paper summarized the annual evolution trend of flood-causing precipitation,and then compared the process information of Chicago rainstorm pattern design precipitation and actual flooding-causing precipitation in terms of peak distribution,intensity and so on.Based on the storm water management model(SWMM),emergence and development distinctions of actual urban flooding with different formation causes in the study area were analyzed,and they were compared with that of floods input by Chicago rainstorm pattern.Results indicated that:(1)During a year,the transition of flood-causing precipitation in Zhengzhou City urban area was from intensity-caused precipitation to dual-caused precipitation,and then to volume-caused precipitation.(2)The flooding process of 2-year Chicago rainstorm pattern in study area was similar to the volume-caused precipitation,while floods caused by 5-year and higher standard Chicago rainstorm pattern had the characteristics of dual-caused precipitation.(3)The flooding process of intensity-caused precipitation had short duration and incomprehensive impact,and that of volume-caused precipitation had long duration,while dual-caused precipitation had both above disaster-inducing mechanisms with more wide influnces.The research results have certain significance and important value for urban waterlogging control,sponge city construction and regional flood mitigation.