Parameters influencing the regeneration of a green roofs retention capacity via evapotranspiration

JOURNAL OF HYDROLOGY

卷:523

Article

Poe, Simon¹  Stovin, Virginia¹  Berretta, Christian² 

[1] Univ Sheffield, Dept Civil & Struct Engn, Mappin St, Sheffield S1 3JD, S Yorkshire, England

[2] Univ Leeds, Sch Civil Engn, Leeds LS2 9JT, W Yorkshire, England

关键词: Evapotranspiration;    Green roofs;    Stormwater management;    SuDS;    Retention;   

DOI  :  10.1016/j.jhydrol.2015.02.002

来源: Elsevier

【 摘 要 】

The extent to which the finite hydrological capacity of a green roof is available for retention of a storm event largely determines the scale of its contribution as a Sustainable Drainage System (SuDS). Evapotranspiration (ET) regenerates the retention capacity at a rate that is variably influenced by climate, vegetation treatment, soil and residual moisture content. Experimental studies have been undertaken to monitor the drying cycle behaviour of 9 different extensive green roof configurations with 80 mm substrate depth. A climate-controlled chamber at the University of Sheffield replicated typical UK spring and summer diurnal cycles. The mass of each microcosm, initially at field capacity, was continuously recorded, with changes inferred to be moisture loss/gain (or ET/dew). The ranges of cumulative ET following a 28 day dry weather period (ADWP) were 0.6-1.0 mm/day in spring and 0.7-1.25 mm/day in summer. These ranges reflect the influence of configuration on ET. Cumulative ET was highest from substrates with the greatest storage capacity. Significant differences in ET existed between vegetated and non-vegetated configurations. Initially, seasonal mean ET was affected by climate. Losses were 2.0 mm/day in spring and 3.4 mm/day in summer. However, moisture availability constrained ET, which fell to 1.4 mm/day then 1.0 mm/day (with an ADWP of 7 and 14 days) in spring; compared to 1.0 mm/day and 0.5 mm/day in summer. A modelling approach, which factors Potential Evapotranspiration (PET) according to stored moisture content, predicts daily ET with very good accuracy (PBIAS = 2.0% [spring]; -0.8% [summer]). (C) 2015 Elsevier B.V. All rights reserved.

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