Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, PA, 15261, USA.
Department of Geology and Environmental Science, University of Pittsburgh, Pittsburgh, PA, 15261, USA.
J Environ Manage. 2024 Nov;370:122831. doi: 10.1016/j.jenvman.2024.122831. Epub 2024 Oct 15.
Green roof systems (GRs) are effective tools for urban stormwater management. However, there is limited documentation of the long-term hydrological performance of GRs to support decision-making. This study evaluated long-term field monitoring records (7 years) from a 12-year-old GR, situated in a Moist Subtropical Mid-Latitude Climate, to analyze seasonality in and evolution of hydrological performance. The monitoring system was built within a pan lysimeter buried under substrate layers matching the surrounding GR. The monitoring results highlight the efficacy of this GR in long-term stormwater runoff control. The GR can retain 87% of the annual precipitation and return 54% of the precipitation to the atmosphere through evapotranspiration (ET) and sustain long-term event-based mean runoff volume reductions, peak flow reductions, and flow delays of 82%, 93%, and 4.3 h, respectively. The initial moisture content prior to events was highly correlated with hydrological performance, with a seasonal mean Spearman correlation coefficient of 0.47, suggesting the potential of enhancing ET from the GR to improve performance. Substrate water holding capacity increased over time, but no obvious changes in water retention performance were observed. These monitoring results from the aging GR demonstrate the effectiveness of GR systems for long-term stormwater management.
绿色屋顶系统（GRs）是城市雨水管理的有效工具。然而，对于支持决策的 GR 长期水文性能，目前的文献记录有限。本研究评估了位于湿润亚热带中纬度气候区的一个 12 岁 GR 的长期现场监测记录（7 年），以分析水文性能的季节性和演变。监测系统建在一个埋在与周围 GR 匹配的基质层下的整层测渗仪内。监测结果突出了这种 GR 在长期雨水径流控制中的有效性。GR 可以保留 87%的年降水量，通过蒸散（ET）将 54%的降水量返回大气，并维持长期基于事件的平均径流量减少、峰值流量减少和流量延迟分别为 82%、93%和 4.3 小时。事件前的初始含水量与水文性能高度相关，季节性平均斯皮尔曼相关系数为 0.47，这表明可以提高 GR 的蒸散能力来提高性能。随着时间的推移，基质的持水能力增加，但没有观察到保水性能的明显变化。老化 GR 的这些监测结果表明，GR 系统对于长期雨水管理是有效的。
