生物滞留池的产流规律模拟研究

根据生物滞留池降雨径流观测试验数据,应用HYDRUS-1D对生物滞留池在24h不同降雨频率和不同填料层的产流规律进行模拟分析。结果表明,率定和验证后的HYDRUS-1D可用于模拟生物滞留池的产流过程;在1年一遇(P=100%)到百年一遇(P=1%)的不同频率下,传统填料的生物滞留池通过下渗的排水量占入流总量的百分比从90.7%下降到25.8%,而添加大粒径颗粒填料从88.9%下降到64.7%,说明添加大粒径填料能够显著增加下渗量,并减少溢流和积水时间,但是从延缓产流时间和洪峰削减效果(不发生溢流)方面,传统填料要优于添加大粒径颗粒的填料。

Study on Runoff of Bioretention by Model Simulation

To investigate the runoff of bioretention, a rainfall-runoff relationship experiment was conducted. HYDRUS-1D model was applied to simulate the runoff generation processes with different designed precipitation frequency and filter media. The simulated runoff process and ponding duration were in good consistence with the measured data. The results show that the model is able to capture the runoff processes reasonably well of bioretention after parameter calibrated and model validation. With designed precipitation frequency changed from P=100% to P=1% as the rainfall depth from 48.1mm to 423.4mm in 24 hours, the infiltration depth to total flow changed from 90.7% to 25.8% for bioretention with traditional filter media, while it changed from 88.9% to 64.7% for bioretention with large particle filter media. The simulated results indicate that the infiltration capability of bioretention with large particle filter media is better than with traditional filter media, and reducing the amount of outflow and ponding time obviously. However, the delay period with traditional filter media is longer than with large particle filter media. Also the peak flow reduction of the bioretention with traditional filter media is larger than large particle filter media before over flood occurrence.