Evapotranspiration performance of green roof system using different types of local vegetation

Kasmin, Hartini and Baharuddin, Sitinurr Hidayu and Abd Aziz, Ahmad Afdhal and Sharif, Nur Durrah (2017) Evapotranspiration performance of green roof system using different types of local vegetation. In: Water and Environmetal Issues. Penerbit UTHM, pp. 90-106. ISBN 9789672110545

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Abstract

Green roof is a technology of incorporation plants with build environment. Green roof or vegetated roof is a roof which is partially or completely covered with vegetation and soil or growing medium. Evapotranspiration (ET) is one of a key parameter that influences the stormwater retention capacity, and thus the hydrological performance of green roofs. This paper investigates on how the moisture content in extensive green roofs varies during dry periods due to evapotranspiration performance for a proposed green roof system using different types of vegetation. The ET experiments were done in 2014, 2015 and 2016, separately using three types of vegetation; Wedelia Tilobata, Portulaca sp, and Arachis Pintoi. However, due to limited supply, Arachis Pintoi was substituted into Japanese Grass in 2016. In each experiment, four different test beds were used; three test beds for three vegetation and the other one was used as a control with substrate layer only. The weight of test beds were measured and recorded daily. Changed in weight mass represents the water loss by ET for vegetated roofs and evaporation (E) for the non-vegetated roof. It was observed that from three series of ET experiments; after 5 days, Wedilia Tilobata test bed has shown better water reduction than Portulaca sp. However, the percentage of reduction quite varies between experiment in 2014 and 2015 although the temperature quite similar between 28˚C and 32˚C. This may due to the system of drainage constructed for the green roof setup, the density of the root and vegetation growth and the influence of other climatic condition such as wind and radiation of the surrounding. The performance of Arachis Pintoi also quite varies between these experiments, however, the performance of water reduction for Arachis Pintoi seems better than Portulaca sp within the similar temperature; but the water losses of Japanese Grass test bed in 2016 displayed the lowest between these other three vegetation. Still, when compared to the non-vegetated roof, all four vegetation exhibited higher water loss, but Japanese Grass test bed start to lose more than the non-vegetated after ten days of dry days, or else it seems simulating the non-vegetated performance. It can be concluded that the understanding on how the rate of evapotranspiration will differ between different types of drought tolerance vegetation to local weather, would greatly benefit in developing a more effective green roof structure.

Item Type:Book Section
Uncontrolled Keywords:Green roof; evaporation; evapotranspiration; urban stormwater
Subjects:T Technology > TH Building construction > TH845-895 Architectural engineering. Structural engineering of buildings
Divisions:Faculty of Civil and Environmental Engineering > Department of Water and Environmental Engineering
ID Code:10566
Deposited By:Mr. Mohammad Shaifulrip Ithnin
Deposited On:11 Feb 2019 08:51
Last Modified:11 Feb 2019 08:51

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