The water storage capacity of a green roof generates several benefits for the building contermi-nous environment. The hydrologic performance is conventionally expressed by the runoff coeffi-cient, according to international standards and guidelines. The runoff coefficient is a dimension-less number and defines the water retention performance in a long period. At the scale of single rain events, characterized by varying intensity and duration, the reaction of the green roof is scarcely investigated. The purpose of this study is to highlight how an extensive green roof – hav-ing a supposed minimum water performance, compared to intensive ones – responses to real and repetitive rain events, simulated in a rain chamber with controlled rain and runoff data. The ex-periment provides, through cumulative curves graphs, the behaviour of the green roof sample during 4 rainy days. The simulated rain events are based on a statistical study (summarized in the paper) on 25 years of rain data for a specific location in North-Italy characterized by an av-erage rain/year of 1,100 mm. The results prove the active response of the substrate, although thin and mineral, and so quit draining, in terms of water retention and detention during intense rain events. The study raises questions about how to better express the water performance of green roofs.

Hydrologic Performance of an Extensive Green Roof under Intense Rain Events: Results from a Rain-Chamber Simulation

Giacomello, Elena
;
Gaspari, Jacopo
2021-01-01

Abstract

The water storage capacity of a green roof generates several benefits for the building contermi-nous environment. The hydrologic performance is conventionally expressed by the runoff coeffi-cient, according to international standards and guidelines. The runoff coefficient is a dimension-less number and defines the water retention performance in a long period. At the scale of single rain events, characterized by varying intensity and duration, the reaction of the green roof is scarcely investigated. The purpose of this study is to highlight how an extensive green roof – hav-ing a supposed minimum water performance, compared to intensive ones – responses to real and repetitive rain events, simulated in a rain chamber with controlled rain and runoff data. The ex-periment provides, through cumulative curves graphs, the behaviour of the green roof sample during 4 rainy days. The simulated rain events are based on a statistical study (summarized in the paper) on 25 years of rain data for a specific location in North-Italy characterized by an av-erage rain/year of 1,100 mm. The results prove the active response of the substrate, although thin and mineral, and so quit draining, in terms of water retention and detention during intense rain events. The study raises questions about how to better express the water performance of green roofs.
2021
Inglese
13
6
3078 article number
23
Internazionale
https://www.mdpi.com/2071-1050/13/6/3078
Esperti anonimi
green roof; sustainably built environment; rain chamber; water management; water retention; water detention; intense rain event; runoff coefficient; rain peak; peak discharge; cumulative curve; soil sealing; NBS-nature based solutions
no
open
1. Contributo su Rivista::1.1 Articolo su Rivista
info:eu-repo/semantics/article
262
Giacomello, Elena; Gaspari, Jacopo
2
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11578/301829
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