绿色屋顶径流减控效果的监测分析

Monitoring and Evaluation of Green Roof Runoff Reduction Effect

基于3年的连续试验监测与数据分析,揭示绿色屋顶的产流规律,定量识别实际运行过程中绿色屋顶的径流减控效果。结果表明,绿色屋顶的年径流总量控制率为77%,在174场降雨中,绿色屋顶发生产流的有33场,产流多发生在大雨及大雨以上等级降雨中;随着降雨量的增加,绿色屋顶的径流系数逐渐增加,对于暴雨和特大暴雨,绿色屋顶的径流系数分别为0. 35和0. 44;绿色屋顶的场次径流总量控制率普遍在50%以上,且随着降雨总量的增加而逐渐减少,两者呈幂函数关系;绿色屋顶同样具有较好的洪峰流量削减效果,洪峰流量削减率与场次径流总量控制率存在较高的一致性,两者的相关系数为0. 95;绿色屋顶的初损过程对降雨的滞蓄起到重要作用,典型场次的初损占比(初损量与降雨控制总量的比例)最高可达90%,且随降雨总量的增加而减少,两者呈对数函数关系。初损过程对应的年径流总量控制率约为51%,大致相当于10 mm的设计降雨量,即绿色屋顶具有10 mm的调蓄容积。

Based on three years of continuous experimental monitoring data,the runoff generation pattern of green roofs was revealed,and the runoff reduction effect of green roof during actual operation was quantitatively identified. The results showed that the volume capture ratio of annual rainfall of green roof was 77%. Among the 174 rainfall events,the runoff was generated by the green roof only in 33 rainfall events,which mostly occurred in heavy rain and above. As the increase of the total rainfall volume,the runoff coefficient of the green roof gradually increased. For torrential rain and extra torrential rain,the runoff coefficients of the green roof were 0. 35 and 0. 44,respectively. The volume capture ratio of rainfall of the green roof was generally above 50%. With the increase of the total rainfall volume,the volume capture ratio of rainfall was gradually reduced,and there was a power function relationship between them. The green roof also had a good effect on flow peak reduction,which had a high correlation with the volume capture ratio of annual rainfall,and the correlation coefficient was 0. 95. The initial loss process of green roof played an important role in the delay and storage of rainfall. The proportion of initial loss (the ratio of the initial loss to the volume capture of rainfall) of typical events was up to 90%,and it decreased with the increase of the total rainfall volume,showing a logarithmic function relationship.The volume capture ratio of annual rainfall contributed by the initial loss process was about 51%,which was roughly equivalent to 10 mm of design rainfall,indicating the green roof had a storage volume of 10 mm.