绿化屋顶的产流规律及雨水滞蓄效果模拟研究

Study on Runoff and Rainwater Retention Capacity of Green Roof by Experiment and Model Simulation

建筑物屋顶作为城市的"第五面",是城市立体化绿化的重要方面。通过屋顶绿化植被和土壤层的蓄滞作用,可在一定程度上延缓产流时间,减少城市径流,并改善局地微气候条件。开展了绿化屋顶的人工降雨径流观测实验,通过对降雨、径流的观测分析了绿化屋顶的雨水滞蓄效果。建立了描述绿化屋顶降雨产流过程的一维入渗模型HYDRUS-1D,利用实验数据进行了模型的率定和验证;并应用模型模拟分析了降雨频率、土层厚度和土壤类型等因素对绿化屋顶雨水滞蓄效果的影响。实验和模拟结果表明,绿化屋顶具有较好的雨水滞蓄效果,10cm土层厚度的绿化屋顶在不同降雨条件下的蓄滞量可达到16.1～21.6mm;随着土层厚度的增加,蓄滞效果更明显;就雨水蓄滞效果而言,壤土比砂土和粉粘土更适合于绿化屋顶。本研究成果可为城市屋顶绿化的推广应用提供参考。

As ＂the fifth facade＂ of city,the building roof is an important aspect for the cubist urban afforesting and greening.The rainwater retention and storage capacity of vegetation and soil layer on green roofs,to some extent,can reduce the urban stormwater runoff,delay the runoff generation,and improve the microclimate condition as well.In this study,an artificial raining experiment was carried out on green roof to analyze its rainwater storage capacity by measuring the rainfall and runoff.Then,a HYDRUS-1D model was established based on the greened roof structure.After model calibration and validation,it was used to simulate and analyze the influences of some key factors,including the rainfall,soil depth and soil characteristics.According to the experimental and calculated results,the green roof has good rainwater retention and storage capacity.For the green roofs with 10cm soil layer in this study,it varies from 16.1mm to 21.6mm according to different rainfall frequency.The capacity has an increase trend with the increase of soil depth.For the water storage effectiveness,loam is more suitable for roof greening than sandy soil and silt clay.These results can supply helpful information for the widespread implementation of green roofs in urban area.