The vegetated substrate of green roofs may undergo various chemical and physical changes with time. Minidisk infiltrometer (MDI) tests were conducted to assess the short-term variations of the near-saturated hydraulic conductivity, K0, in the extensive green roof test plot established at the University of Palermo. Sampling was repeated four times: before planting (Age 0) and then after four months (Age 1), seven months (Age 2) and ten months (Age 3). A total of 144 infiltration tests were conducted at two pressure heads, h0 = −3 cm and h0 = −0.5 cm and infiltration data analysed by the Zhang (Soil Science Society of America Journal 61(4):1024–1030, 1997) model. Both K-3 and K-0.5 underwent temporal variations resulting in final values that were higher by a factor of 3.0 and 1.4, respectively, than the initial ones. Compaction and washing off of fine particles explained the observed trend in K0 as the lower part of the growing media enriched in fine particles and resulted in higher bulk density than the upper one. The results showed that the hydraulic properties of the growing substrate were subjected to short term modifications that may influence the hydrological performance of the green roof.

Evaluation of Green Roof Ageing Effects on Substrate Hydraulic Characteristics

Alagna V.;Bagarello V.;
2020

Abstract

The vegetated substrate of green roofs may undergo various chemical and physical changes with time. Minidisk infiltrometer (MDI) tests were conducted to assess the short-term variations of the near-saturated hydraulic conductivity, K0, in the extensive green roof test plot established at the University of Palermo. Sampling was repeated four times: before planting (Age 0) and then after four months (Age 1), seven months (Age 2) and ten months (Age 3). A total of 144 infiltration tests were conducted at two pressure heads, h0 = −3 cm and h0 = −0.5 cm and infiltration data analysed by the Zhang (Soil Science Society of America Journal 61(4):1024–1030, 1997) model. Both K-3 and K-0.5 underwent temporal variations resulting in final values that were higher by a factor of 3.0 and 1.4, respectively, than the initial ones. Compaction and washing off of fine particles explained the observed trend in K0 as the lower part of the growing media enriched in fine particles and resulted in higher bulk density than the upper one. The results showed that the hydraulic properties of the growing substrate were subjected to short term modifications that may influence the hydrological performance of the green roof.
Lecture Notes in Civil Engineering
89
97
Alagna V.; Bagarello V.; Concialdi P.; Giordano G.; Iovino M.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/764540
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