The influence of structural factors on stormwater runoff retention of extensive green roofs: new evidence from scale-based models and real experiments

Liu, Wen and Feng, Qi and Chen, Weiping and Wei, Wei and Deo, Ravinesh C. (2019) The influence of structural factors on stormwater runoff retention of extensive green roofs: new evidence from scale-based models and real experiments. Journal of Hydrology, 569. pp. 230-238. ISSN 0022-1694


Green roofs, in contrast to conventional roofs, retain significant stormwater, and are considerably appealing for urban regions to help mitigate flooding events and addressing serious environmental impacts of excessive or uncontrolled runoff. In designing a green roof, a careful selection of substrate material/depths, vegetation or slopes, or its optimal combination, is imperative but this issue remains underexplored by practicing hydrologists. Scale-based models of extensive green roofs were purposely designed and simulated rainfall experiments were conducted to comprehensively quantify runoff retention performance of extensive green roofs, to precisely determine the contribution of structural factors to stormwater retention. The results indicated that green roofs can effectively retain stormwater and delay the start of the runoff. To aver with this finding, influential contribution of four structural factors are ordered as follows: substrate material > substrate depth > slope > vegetation. This finding denotes that substrate material and its depth are major contributors to a green roof’s stormwater retention capability. Statistical tests conducted on runoff retention showed the substrate materials and vegetation types had statistically significant effects, no statistically significant difference in runoff retention abilities among the three substrate depth treatments and the slope gradients considered. Given the same conditions, the study ascertains that runoff retention of low intensity events is likely to be relatively higher, while that of the heavy events is lower than its counterparts. The antecedent moisture contents of the substrate have a significant negative influence on the runoff retention and the time to the runoff.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: This study was supported by Chinese Academy of Sciences grant to Dr Ravinesh C Deo. Permanent restricted access to Published version, in accordance with the copyright policy of the publisher.
Faculty/School / Institute/Centre: Current - Institute for Life Sciences and the Environment
Date Deposited: 19 Dec 2018 02:11
Last Modified: 13 Jun 2019 04:54
Uncontrolled Keywords: green roof; runoff retention; scale model; simulated rainfall; structural factors; substrate
Fields of Research : 09 Engineering > 0905 Civil Engineering > 090509 Water Resources Engineering
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970105 Expanding Knowledge in the Environmental Sciences
Identification Number or DOI: 10.1016/j.jhydrol.2018.11.066

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