Runoff and vegetation stress of green roofs under different climate change scenarios

Vanuytrecht, Eline; Mechelen, Carmen Van; Meerbeek, Koenraad Van; Willems, Patrick; Hermy, Martin; Raes, Dirk

doi:10.1016/j.landurbplan.2013.11.001

Cited by 76 publications

(37 citation statements)

References 39 publications

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“…However, know-how in terms of green roof installation is, in some cases, inadequate to deal with the contrasting environmental conditions that prevail in the Mediterranean region. Research on green roofs currently focuses on cold climates, and may not take into account prolonged periods of drought, extreme temperatures or heavy precipitation, the future climatic conditions due to global changes [3,[13][14][15]. In the Mediterranean context, such severe conditions impose severe restrictions on plant growth and on plant survival [16].…”

Section: Introductionmentioning

confidence: 99%

Substrate Composition and Depth Affect Soil Moisture Behavior and Plant-Soil Relationship on Mediterranean Extensive Green Roofs

Chenot

Gaget

Moinardeau

et al. 2017

Water

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Abstract:The Mediterranean basin is extremely vulnerable to climate change, and one of the areas most impacted by human water demand. Yet the green roofs increasingly created both for aesthetic reasons and to limit pollution and urban runoff are themselves very water-demanding. Successful green roof installation depends on the establishment of the vegetation, and the substrate is the key element: it conserves water, and provides the nutrients and physical support indispensable for plant growth. Since typical Mediterranean plant communities require no maintenance, this study seeks to develop techniques for creating maintenance-and watering-free horizontal green roofs for public or private buildings in a Mediterranean context. The innovative aspect of this study lies in creating two soil mixes, fine elements (clay and silt) and coarse elements (pebbles of all sizes), in two different thicknesses, to assess vegetation development. Monitoring of substrate moisture was carried out and coupled with local rainfall measurements during summer and autumn. As expected, substrate moisture is mainly influenced by substrate depth (the deeper, the moister) and composition (the finer the particles (clays and silts), the higher the moisture content). Vegetation cover impacts moisture to a lesser extent but is itself affected by the composition and depth of the substrates. These results are subsequently discussed with relation to the issue of sustainable green roofs in Mediterranean climates. Considering applications of our results, for an optimal colonization of a Mediterranean vegetation, a substrate thickness of 15 cm composed mainly of fine elements (75% clay-silt and 25% pebble-sand) would be recommended in green roofs.

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Section: Introductionmentioning

confidence: 99%

Substrate Composition and Depth Affect Soil Moisture Behavior and Plant-Soil Relationship on Mediterranean Extensive Green Roofs

Chenot

Gaget

Moinardeau

et al. 2017

Water

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“…For example, simple hydrological models such as the one proposed by Stovin et al (2013) can perform long-term, continuous simulations to estimate runoff and evaluate drought risks. Vanuytrecht et al (2014) developed a model based on water balance at daily scales. An analytical, probabilistic model for evaluating the long-term hydrologic performance of extensive green roofs was proposed by Zhang and Guo (2013).…”

Section: Introductionmentioning

confidence: 99%

Saturation-excess and infiltration-excess runoff on green roofs

Yang

Sun

et al. 2015

Ecological Engineering

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“…A key aim of our study was to determine whether it would be possible to model the retention performance of alternative substrates in the absence of runoff data, recognising that such data may not be available in practice. Adjusting standard laboratory-based measures of WHC or PAW to minimise the over-estimation of retention would be a useful starting point to improve existing models that assume maximum storage equal to the WHC or PAW of the substrate [50]. We are not suggesting that green roof water balance models should change the fundamental assumption that runoff will only occur once substrate storage capacity is reached.…”

Section: Relationship Between Substrate Water Storage and Rainfall Rementioning

confidence: 99%

Laboratory Tests of Substrate Physical Properties May Not Represent the Retention Capacity of Green Roof Substrates In Situ

Szota

Fletcher

Desbois

et al. 2017

Water

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Green roofs can be used to reduce the volume of polluted stormwater that is generated by cities. Modelling rainfall retention is critical, but green roof water balance models often rely on the physical properties of substrates. In these models, substrate water holding capacity (WHC) determines the depth of water which can be stored before runoff is generated; whereas, the permanent wilting point (PWP) limits evapotranspiration. The WHC and PWP, as well as plant available water (PAW; where PAW = WHC − PWP), as determined from laboratory tests, may not truly reflect how substrates perform on green roofs. We therefore ran a simulated rainfall experiment on green roof modules to (i) compare the rainfall retention of vegetated and non-vegetated substrates with different WHC and PAW, and (ii) relate retention to substrate storage capacity, as calculated from laboratory measures of WHC and PAW. We found that the PAW of a substrate is a better indicator of evapotranspiration and retention when compared with WHC. However, we also found that substrates always retained less water than their calculated storage capacity would suggest, most likely being due to their high permeability. Our results indicate that using laboratory-derived measures of WHC and PAW in green roof models may be over-estimating both evapotranspiration and rainfall retention.

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Runoff and vegetation stress of green roofs under different climate change scenarios

Cited by 76 publications

References 39 publications

Substrate Composition and Depth Affect Soil Moisture Behavior and Plant-Soil Relationship on Mediterranean Extensive Green Roofs

Substrate Composition and Depth Affect Soil Moisture Behavior and Plant-Soil Relationship on Mediterranean Extensive Green Roofs

Saturation-excess and infiltration-excess runoff on green roofs

Laboratory Tests of Substrate Physical Properties May Not Represent the Retention Capacity of Green Roof Substrates In Situ

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