北京市生物滞留池径流调控效益研究

Runoff control performance of a field scale bioretention cell in Beijing

生物滞留池是海绵城市建设的重要措施之一,具有径流调控和生态修复等功能。然而,在北方城市,有关生物滞留池径流调控效益的研究仍相对匮乏。研究基于2020至2022年雨季(5至9月)对位于北京市西郊的生物滞留池50场降雨径流过程监测数据,定量分析了生物滞留池径流调控效益变化特征及其主控因素。结果表明:生物滞留池具有良好的径流调控效益,场降雨径流削减率(R_(V))、峰值削减率(R_(p))和峰值延迟时间比(R_(d))分别为43.27%~99.89%,43.71%~99.27%和1.01~45.50。根据开发前、后径流系数比,将R_(V)和R_(p)的调控目标均设为67%,根据开发前、后汇流时间比,将R_(d)的调控目标设为6,生物滞留池R_(V)、R_(p)和R_(d)超过调控目标的概率分别为86%、90%和18%。R_(V)与降雨量、平均降雨强度和降雨历时呈显著负相关(P<0.05),R_(p)和R_(d)均与降雨量和降雨历时呈显著负相关(P<0.05)。研究结果可望为北方城市生物滞留池的水文设计和径流调控效益评估提供数据支撑与科学参考。

Bioretention cells are one of the important measures for the sponge city construction,with their functions of stormwater regulation and ecosystem restoration.However,there is still a lack of understanding about the runoff control performance of bioretention cells in northern cities.In this study,rainfall-runoff processes of 50 rainfall events of a bioretention cell located in the western suburb of Beijing were obtained by continuously monitoring during rainy season(from May to September)from 2020 to 2022,and the change characteristics of runoff control performance of the bioretention cell was quantitively evaluated.Furthermore,the main factors that affecting runoff control performance of the bioretention cell were analyzed.The results showed that:The bioretention cell had good runoff control performance,with runoff reduction ratio(R_(v)),peak reduction ratio(R_(p)),and peak delay ratio(R_(d))ranging from 43.27%to 99.89%,43.71%to 99.27%,and 1.01 to 45.50,respectively.The Rv and R,control targets were set at 67%according to the ratio of runoff coefficients pre-development and post-development,and the Ra control target was set at 6 according to the ratio of time of runoff concentration pre-development and postdevelopment.The probabilities of the R_(v),R_(p),and R_(d) exceeding the control targets were 86%,90%,and 18%,respectively.The R_(v) was negatively correlated with rainfall amount,average rainfall intensity and rainfall duration(P<0.05).R_(p) and R_(a) were both negatively correlated with rainfall amount and rainfall duration(P<0.05).These results provide data and scientific references for hydrologic design and runoff control performance evaluation of bioretention cells in northern cities.