北京地区绿色屋顶的径流特征研究

Runoff Characters of Green Roof in Beijing

国内外运用绿色屋顶作为截留雨水的措施得到广泛实践。依托北京市园林科学研究院覆土实验站,基于绿色屋顶观测试验结果,初步定量研究了北京城市气候下简单式和花园式两种绿色屋顶对屋面径流的影响。结果表明:对照屋顶、简单式绿色屋顶和花园式绿色屋顶的平均雨水滞留率分别为15.1%、64.7%和78.5%。两种绿色屋顶在小雨条件下雨水滞留率差异不显著,在中到大雨条件下二者差异显著。降雨强度对花园式绿色屋顶径流过程影响较小,花园式绿色屋顶对大雨的滞留效果更明显。花园式绿色屋顶对总氮和氨氮的控制效果比简单式绿色屋顶好,但二者都表现为磷的释放。花园式绿色屋顶的污染负荷削减率高于简单式绿色屋顶,简单式绿色屋顶增加了硝氮和总磷的污染负荷。研究为北京海绵城市建设中绿色屋顶的设计和建造提供理论依据与技术支持。

The use of green roofs as a measure to intercept rainwater has been widely practiced at home and abroad.Relying on the Soil Covering Experimental Station of the Beijing Academy of Landscape Architecture,and based on the results of the green roof observation and experiment,a preliminary quantitative study of the effects of simple and garden green roofs on roof runoff under the urban climate of Beijing was carried out.The results showed that the average rain retention rates of the control roof,simple and garden-style green roofs were 15.1%,64.7%and 78.5%,respectively.There was no significant difference in rain retention rate between the two green roofs under light rain conditions,but significant difference between them under moderate to heavy rain conditions.Rainfall intensity had little effect on the runoff process of garden green roofs,and garden green roofs had more obvious retention effects on heavy rain.Garden green roofs had better control effects on TN and NH_(3)-N than simple green roofs,but both were manifested by the release of phosphorus.Garden green roofs could reduce the pollution load of COD,SS,TN and NH_(3)-N in rainfall runoff more than simple green roofs,while simple green roofs increase the pollution load of NO_(3)-N and TP.This research will provide theoretical basis and technical support for the design and construction of green roofs in the Spongy City of Beijing.