老城区海绵改造降雨致涝及污染物输移过程数值模拟——以西安市小寨老城区为例

Numerical Simulation of Rainfall-induced Flooding and Pollutant Transport in Sponge Reconstruction of Old City——Taking Xiaozhai Old Town as an example

以西安市小寨老城区为例,采用二维城市雨洪模型模拟分析海绵改造前后不同降雨重现期下的降雨致涝和污染物输移过程。结果表明:改造后小寨老城区2年一遇降雨条件下未出现明显积水;20年一遇降雨条件下由改造前15处积水减少为改造后5处积水;50年一遇设计降雨条件下由改造前29处减少到改造后13处积水。对比小寨老城区海绵改造前后积水水量,2、20、50 a重现期下积水水量峰值分别削减62.04%、37.13%、32.43%;污染物扩散面积和降雨重现期相关,50年一遇降雨重现期下污染物扩散面积最大。

Taking the Old Town of Xiaozhai in Xi'an as an example,a two-dimensional urban rain and flood model was used to simulate and analyze the process of rain-induced waterlogging and pollutant transport under different rainfall return periods before and after sponge reconstruction.The results show that after the reconstruction,there is no obvious accumulation of water in the old town of Xiaozhai under the condition of rainfall with return period of once every 2 years.Under the condition of rainfall with return period of once every 20 years,the number of water accumulation sites was reduced from 15 before the reconstruction to 5 after the reconstruction.Under the condition of rainfall with return period of once every 50 years,the number of water accumulation sites decreases from 29 before reconstruction to 13 after reconstruction.Comparing the accumulation of water before and after the sponge transformation in Xiaozhai old city,the peak accumulation of water under rainfall with the return period of 2 years,20 years,and 50 years was reduced by 62.04%,37.13%,and 32.43%respectively;The diffusion area of pollutants is related to the rainfall return period,and the diffusion area of pollutants is the largest under rainfall with return period of 50 years.