郑州市“7.20”暴雨与10年一遇设计暴雨条件下的积水特性对比分析

Analysis of Waterlogging Characteristics of“7.20”Rainstorm and Greater Designed Rainstorm in Zhengzhou

为进一步区分极端罕见暴雨与一般大暴雨对城市内涝影响的不同,采用SWMM雨洪模型,分析郑州市金水区“7.20”暴雨与10年一遇设计暴雨情境下的城市暴雨内涝积水特性变化。结果表明,郑州市金水区排水除涝标准较低,仅能抵抗1.5年一遇暴雨内涝风险;郑州市“7.20”暴雨和10年一遇设计暴雨均能引起城市内涝,且“7.20”暴雨内涝积水严重程度均远高于10年一遇设计暴雨内涝积水严重程度;与10年一遇设计暴雨相比,“7.20”暴雨情境下管段超载程度、排水能力及管网流量均达到上限,内涝积水点数量及积水范围增大,且主要集中于东南部,积水峰值时间相对于暴雨峰现时间推迟了1 h;受连接管段数量和坡度的影响,各排放口的径流量特性有所差异,各排放口洪峰时间比其雨峰平均推迟了1.4 h。研究成果可为城市雨洪应急管理提供参考。

In order to further distinguish extreme rainstorms from the influence of general heavy rains on urban waterlogging,SWMM model was used to analyze the waterlogging characteristics of“7.20”rainstorm and the designed rainstorm of 10 a return period in the Jinshui District of Zhengzhou city.The results show that the drainage standards of the Jinshui District is lower and only resist the rainstorm of 1.5 a return period.“7.20”rainstorm and designed rainstorm of 10 a return period are both induced in waterlogging,and also the waterlogging risk of“7.20”rainstorm is greater than rainstorm of 10 a return period.Compared with rainstorm of 10 a return period,the drainage overloading,capacity and flows are all reached the upper limit,and the number and range of waterlogging points are increased,which are mainly concentrated in the southeast of the district.Moreover,the waterlogging remaining time is closely with the rainstorm peak.Due to the effect of the number and slope of the connecting pipes,the discharge characteristics of outlets are different,and the flood peak is delayed by 1.4 h on average.Research results can provide guidance for urban rainfall flood emergency management.