建筑尺度屋顶绿化与雨水收集集成系统的雨洪调控效应评价

Evaluation of Stormwater Regulation Effect on Integrated System of Green Roof and Rainwater Collection System on Building Scale

屋顶绿化与雨水收集集成系统是海绵城市建设雨洪调控的“黄金组合”。以南京市金陵小学行政楼为例,基于多年观测数据,分析了屋顶绿化的雨洪调控效应,即采用决策树分类算法揭示了影响其雨洪调控效应的主要因子,进而基于SWMM模型分析了不同降雨事件下6种屋顶绿化与雨水收集集成系统组合方案的雨洪调控效应。研究结果表明,屋顶绿化可有效减少地表径流、降低峰值流量、推迟产流与峰现时间,具备较强的雨洪调控能力,但在强降雨事件下其调控能力会大幅降低;影响屋顶绿化雨洪调控能力的主要影响因子为降雨量、降雨重现期和降雨强度;屋顶绿化与雨水收集集成系统能很好地协同应对较强降雨事件产生的地表径流,且雨水收集系统的容积越大所发挥的调控效应亦越大。该结果可为海绵城市的规划建设与政策制定提供决策参考。

The integrated system of green roof and rainwater collection is the "golden combination" of stormwater regulation in sponge city construction. This study takes the administrative building of Jinling Primary School in Nanjing as the study area. Based on multi-year observed data, this paper analyzed the stormwater regulation effects of Green Roof and its main impact factors by decision tree algorithm. Furthermore, six combined schemes were conducted in SWMM model under different kind of rain events to assess the effect of "golden combination". The results show that green roof can reduce both surface runoff and peak flow efficiently and postpone runoff generation and peak time, but its regulation capacity will significantly decrease under heavy rainfall events. The main impact factors of green roof stormwater regulation effect are the total rainfall depth and rainfall intensity and retain period. The "golden combination" can reduce surface runoff synergistically under heavy rainfall events. As the collection volume increases, the regulation effect will increase as well. The results of this study can provide decision-making reference for planning and policy making for sponge city.