通过模拟降雨强度5080 mm的降雨实验,研究了3种常用基质(商业基质、火山岩基质和田园土基质)绿色屋面的径流滞留率和径流水质的特点.结果表明:商业基质的径流滞留率最高,达到48.6%,火山岩基质和田园土基质的滞留率分别为33.6%和30.4%;随着降雨历时的延长,3种基质屋面径流中各水质参数浓度呈现出逐渐降低的趋势,但是,随着降雨强度的加大,商业基质径流中TN浓度和COD呈现出逐渐升高的趋势,而火山岩和田园土基质径流水质参数未呈现出明显变化;田园土基质屋面径流EC、TN、COD、TP和TSS的浓度均值高达3973.54、36.96、503.67、2.64和92.02 mg·L(-1),显著高于商业基质屋面和火山岩基质屋面;商业基质屋面能够有效地中和模拟降雨的pH,且径流中EC、TP和TSS浓度与火山岩基质屋面径流无明显差异.但是,这2种基质屋面径流中TN和COD的浓度(商业基质:17.47 mg·L(-1)和87.99 mg·L(-1),火山岩基质:10.95 mg·L(-1)和157.85 mg·L(-1))均超出国家地表水环境质量V类标准;通过综合分析3种屋面基质径流滞留率和径流水质,认为商业基质是我国北方地区较为适宜的绿色屋面基质.研究结果可为绿色屋面的科学构建和城市暴雨径流管理提供科学依据,并为我国海绵城市的建设提供重要的理论依据.
Based on simulated rainfall events( Rainfall intensity is 50 80 mm),we analyzed that the characteristics of the runoff water quality and retention capacity of three kinds substrate( commercial substrate,volcanic substrate and garden soil substrate) of the modular green roof. The results show that the runoff retention ratio of the commercial substrate is the highest,reaching 48.6%. The runoff retention ratio of the volcanic substrate and garden soil substrate are 33.6% and 30.4%,respectively. The concentration of all water quality parameters in the three substrates runoff shows the declining trend with the extension of rainfall time.However,the concentrations of TN and COD of the commercial substrate runoff show the trend of gradual increased with the increase of rainfall intensity. By comparing the rainfall runoff water quality among the three kinds of substrate,we found that the mean concentration of EC,TN,COD,TP and TSS of the roof of garden soil substrate were 3973.54、36.96、503.67、2.64 and 92.02 mg·L(-1),and were significantly higher thanthe roof of commercial substrate and volcanic substrate. The commercial substrate could neutralize the pH of the experiment water and the concentration of the EC、TP and TSS showed no difference between the roof of commercial substrate and volcanic substrate. The concentration of TN and COD of the commercial substrate( 17.47 and 87.99 mg·L(-1)) and volcanic substrate(10.95 and 157.85 mg·L(-1)) runoff were exceed the Class Ⅴ level of surface water. Basing on analyzing the runoff water quality and the retention capacity of the three kinds roof substrate,the commercial substrate is more suitable for green roof substrate in north China. The results would provide the scientific basis for designing and applying the green roof,managing and controlling the urban storm runoff,and then to offer the data support for constructing the sponge city in China.