College of Civil Engineering and Architecture, Guangxi University, Nanning 530004, PR China.
College of Civil Engineering and Architecture, Guangxi University, Nanning 530004, PR China; Hualan Design & Consulting Group, Nanning, 530004, PR China.
J Environ Manage. 2021 Sep 1;293:112952. doi: 10.1016/j.jenvman.2021.112952. Epub 2021 Jun 5.
Bioretention has been widely used in China for the purpose of sponge city construction. In subtropical climate areas, the performance of bioretention cell under condition of low infiltration underlying soil and heavy storms is still poorly understood. This study aimed to assess the effects of low infiltration underlying soil and precipitation characteristics on the hydraulic performance of a bioretention cell using the Storm Water Management Model (SWMM). The hydraulic performance of a bioretention cell were investigated under a Typical year rainfall event (P (total precipitation) = 1299.2 mm) and seven heavy storms (i.e., P range from 53.1 mm to 287.3 mm), at different S (seepage rates of the underlying soil) (i.e., range from 2.5 mm/h to 15 mm/h). Then, sensitivity of the optimal design to the different design parameters, including the hydraulic conductivity of soil medium layer and the berm height of surface layer, was examined. The results show that the increase in S was effective in increasing the AR (annual runoff volume reduction) and R (runoff volume reduction), while little effective in increasing P (peak flow reduction). Moreover, the AR could meet the designed goal of 70% when the S was more than 7.5 mm/h. For R, the key variable of precipitation characteristic changes from P to P (maximum precipitation in 4 h) as S increases, while P remains as the key variable for P all the time. The sensitivity studies demonstrate that the hydraulic conductivity is more effective in increasing P than the berm height. For the bioretention cell under condition of low infiltration underlying soil and heavy storms, in order to simultaneously achieve expected reduction goal of both peak flow and runoff volume, and make the best comprehensive performance of bioretention cell, it requires not only a maintenance action to increase the hydraulic conductivity of soil medium layer, but also a drain pipe to be added in the storage layer, and meanwhile other LID practices should be combined.
生物滞留技术在中国被广泛应用于海绵城市建设。在亚热带气候地区，对于低渗透性下层土壤和暴雨条件下生物滞留池的性能仍了解甚少。本研究旨在利用雨水管理模型（SWMM）评估低渗透性下层土壤和降水特征对生物滞留池水力性能的影响。在典型年降雨量事件（P（总降雨量）= 1299.2mm）和 7 次暴雨（即 P 范围为 53.1mm 至 287.3mm）下，研究了不同 S（下层土壤渗透速率）（即 2.5mm/h 至 15mm/h）条件下生物滞留池的水力性能。然后，考察了不同设计参数（包括土壤介质层的水力传导率和表层堤岸高度）对最优设计的敏感性。结果表明，S 的增加有效提高了 AR（年径流量减少量）和 R（径流量减少量），但对 P（峰值流量减少量）的影响不大。此外，当 S 大于 7.5mm/h 时，AR 可满足 70%的设计目标。对于 R，随着 S 的增加，降水特征的关键变量从 P 变为 P（4 小时内最大降雨量），而 P 一直是 P 的关键变量。敏感性研究表明，水力传导率比堤岸高度更有效地提高 P。对于低渗透性下层土壤和暴雨条件下的生物滞留池，为了同时实现预期的峰值流量和径流量减少目标，并使生物滞留池的综合性能达到最佳，不仅需要采取维护措施来提高土壤介质层的水力传导率，还需要在储存层中添加排水管，同时还应结合其他低影响开发实践。
