双基质层绿化屋面的雨水水文水质特征分析

绿化屋面作为低冲击开发的常用措施之一，能有效削减暴雨径流、延缓产流时间，从而缓减城市市政管网的压力。但绿色屋面暴雨径流的水质特征依然存在很多不确定性。在天津市气候条件下，通过搭建不同厚度的“双基质层”绿化屋面小试实验装置开展人工降雨实验，着重研究分析了不同降雨条件下，绿化屋面的产流过程以及绿化屋面暴雨径流中污染物的平均出水浓度与吸附基质层厚度、降雨强度的关系。结果表明，产流阶段的产流速度与降雨总量无关，只与降雨强度有关，径流累积量与降雨强度无关，与填料层厚度和降雨总量有关；污染物径流平均浓度与吸附基质层厚度、降雨强度有关；绿色屋顶能够有效降低雨水的COD和浊度，且对酸雨有较好的中和作用。

Analysis of characteristics of hydrology and rainwater quality of the dual-substrate-layer green roof

A green roof serves as an important technical component of low-impact development (LID). From the perspective of water management, green roofs play an important role in easing the demand on the municipal pipe network, because of their ability to retain and detain storm water. However, the water quality of rain runoff is subject to considerable uncertainty. The present study analyzed the effluent process, the relationship between event mean concentrations (EMC) of pollutants and adsorption substrate thickness, and rainfall intensity. Four pilot-scale green roof trays with artificial rainfall devices were constructed on a normal roof in the Tianjin area. The findings clearly demonstrate that the velocity of effluent was not relevant to total rainfall volume in the effluent production stage, but was only determined by rainfall intensity; the volume of accumulative runoff was relevant to substrate depth and total volume of rainfall; the EMC of pollutants was correlated with the absorption substrate depth and rainfall intensity; and green roofs effectively reduced COD and turbidity value, and neutralized acid rain to stabilize the pH of the runoff.