Bondì C, Concialdi P, Iovino M, Bagarello V
Dipartimento di Scienze Agrarie Alimentari e Forestali, Università degli Studi di Palermo, Italy.
Centro Interdipartimentale di Ricerca "MIGRARE. Mobilità, differenze, dialogo, diritti", Università degli Studi di Palermo, Italy.
Heliyon. 2023 Jun 2;9(6):e16829. doi: 10.1016/j.heliyon.2023.e16829. eCollection 2023 Jun.
Green roof detention capacity is related to the steady-state infiltration rate, , of the growing medium. With the aim to investigate short- and long-term modifications of the detention capacity of an extensive Mediterranean green roof, three mini-disk infiltrometer (MDI) measurement campaigns were conducted at construction, after one season and after five years of operation. A laboratory experiment was designed to separately measure in the upper and the lower part of the substrate profile. During the first operating season, field increased by a factor of 2.4 and 1.9 for near-saturated (applied pressure head, = -30 mm) and quasi-saturated conditions ( = -5 mm), respectively. Similar rainfall height did not induce significant modifications in the upper layer of the laboratory columns, even if contribution of small pores to water infiltration tended to increase. Differently, significantly decreased by a factor of 3.4-5.3 in the lower layer. After the simulated rainfall, the upper layer was less packed (mean bulk density, ρ = 1.083 kg m) and the lower layer was more packed (ρ = 1.218 kg m) as compared with the initial density (ρ = 1.131 kg m) and the lower part enriched in small particles. Short-term modifications in the experimental plot were thus attributed to fine particles washing-off and bulk density decrease in the upper layer, yielding an overall more conductive porous medium. After five years of green roof operation, field did not further increase thus showing that the washing/clogging mechanism was complete after one season or it was masked by counteracting processes, like root development and hydrophobicity.
绿色屋顶的滞蓄能力与生长介质的稳态入渗率有关。为了研究地中海式粗放型绿色屋顶滞蓄能力的短期和长期变化，在建造时、运行一个季节后以及运行五年后，进行了三次小型圆盘入渗仪（MDI）测量活动。设计了一项实验室实验，以分别测量基质剖面上下部分的入渗率。在第一个运行季节，近饱和（施加压力水头，h = -30毫米）和准饱和条件（h = -5毫米）下的田间入渗率分别增加了2.4倍和1.9倍。即使小孔对水分入渗的贡献趋于增加，相似的降雨高度也未引起实验室柱上层的显著变化。不同的是，下层的入渗率显著下降了3.4至5.3倍。模拟降雨后，与初始密度（ρ = 1.131千克/立方米）相比，上层的压实程度较低（平均容重，ρ = 1.083千克/立方米），下层的压实程度较高（ρ = 1.218千克/立方米），且下层富含小颗粒。因此，实验区的短期变化归因于上层细颗粒的冲刷和容重的降低，从而产生了总体上更具传导性的多孔介质。绿色屋顶运行五年后，田间入渗率没有进一步增加，这表明冲刷/堵塞机制在一个季节后就已完成，或者被诸如根系发育和疏水性等抵消过程所掩盖。
