设计暴雨雨型对城市内涝影响数值模拟

Numerical simulation of design storm pattern effects on urban flood inundation

为分析设计暴雨雨型对城市内涝的影响,应用耦合了水文和水动力过程的数值模型,以陕西省西咸新区为研究区域,对不同重现期及峰值比例设计暴雨条件下的内涝过程进行模拟,并对内涝积水总量、不同积水深度内涝面积等量值进行对比分析。结果表明:设计暴雨重现期短于20年时,峰值比例较小的设计暴雨内涝积水总量较大,而重现期长于20年时,规律相反;除2年一遇设计暴雨外,峰值比例较大的设计暴雨致涝总面积较大,但其中影响严重的Ⅳ级致涝面积较小;设计暴雨峰值比例越小,重现期越长,积水总量峰值时刻相对于暴雨峰值时刻的迟滞时间越长。揭示了暴雨雨型与内涝积水程度的量化规律,对更合理地开展城市雨洪管理工作具有指导意义。

Aiming to investigate the influence of design storm pattern on urban flood inundation, this work applies a numerical model to simulate the hydrological and hydrodynamic processes and analyze urban flood inundation patterns in Xi＇an New Area, Shaanxi Province, China. Design hyetographs with different position coefficients for the storm peak and return period are considered. By comparing the simulation results in terms of water depth and inundation ex- tent, it is found that the lower position coefficients of storm peak with the return period less than 20 a may cause more total inundation, but opposite conclusion may be drawn for the storms with the return period greater than 20 a. Apart from the return period of 2 a, the storms with a higher position coefficient of storm peak will result in more total inun- dation, but the more serious IV-level inundation is reduced. With a lower position coefficient of storm peak and longer return period, the lag between the times to the peak inundation and to the storm peak becomes bigger. This work dem- onstrates quantitatively the effects of design storm pattern on urban flood inundation. The research may help make more informed decisions on urban flood management.