西咸新区降雨空间非一致性对内涝过程影响模拟研究

Effects of rainfall spatial inconsistency on flood inundation processes in the Xixian New Area

为分析降雨空间分布非一致性对城市内涝的影响,应用耦合了水文和水动力过程的数值模型,以陕西省西咸新区海绵城市部分核心试点区为研究区域,对不同重现期设计暴雨及离差系数Cv条件下的内涝过程进行模拟,并对内涝积水总量峰值、重度内涝积水总量峰值及其与均匀降雨情况下的内涝积水削减进行对比分析。结果表明:相比于空间均匀降雨,各重现期下空间分布不均匀的内涝积水量均会减少。各重现期下,Cv值越大,即降雨越不均匀,相比于均匀情况内涝积水削减量越大。当Cv值为0.07、0.11、0.15及0.2时,积水总量削减率分别为1.94%~2.05%,3.00%~3.17%,4.08%~4.23%,4.86%~5.15%。重度内涝情况下,同一Cv值,相比于均匀情况内涝积水削减量随设计降雨重现期变长而增多,当Cv=0.07、Cv=0.11、Cv=0.15、Cv=0.20时,削减率的范围分别为2.00%~2.51%、2.60%~3.82%、3.66%~4.98%、3.80%~5.83%。研究结果揭示了降雨空间分布非一致性对内涝的影响规律,为城市内涝防治工作提供了理论依据。

The effects of rainfall spatial inconsistency on urban flood inundation was investigated in this study with a numerical model under the conditions of designed rainstorm and uneven coefficient Cvfrom different return periods for the Xixian New Area,Shaanxi Province,China.Total volumes of peak waterlogging,volumes of severe peak waterlogging and their reduction rates under uniform rainfall were compared and analyzed.It is found that the waterlogging volumes under uneven spatial distribution decreases in each return periods in comparison with the spatial uniform rainfall..The waterlogging reduction magnitudes under uneven rainfall increases as the Cvvalue increases for every return period.,For example,when the Cvvalues are 0.07,0.11,0.15 and0.2,the reduction rates are 2.05%~1.94%,3.00%~3.02%,4.23%~4.08%,4.86%~5.10%,respectively.In the case of severe waterlogging,in comparison with spatial uniform rainfall with same Cv values,the longer the return period,the higher the reduction amount of waterlogging increases.For example,when the Cv value are 0.07,0.11,0.15 and 0.2,the reduction rates are 2.00%to2.51%,2.60%to 3.82%,3.66%to 4.98%,and 3.80%to 5.83%,respectively.The simulation demonstrates the effects of rainfall spatial inconsistency on urban flood inundation and provides a theoretical basis for urban flood management.