Author(s): Ly Voyde; Elizabeth Fassman; Robyn Simcock
Linked Author(s):
Keywords: Living roof; Eco-roof; Green roof; Hydrology; Runoff reduction; Stormwater mitigation
Abstract: Living roof technology is emerging as a low impact development method for stormwater management suitable for retrofit in densely developed urban centres. This paper presents results of field monitoring of a 235 m 2 extensive living roof suitable for retrofit installation in Auckland, New Zealand (NZ), to quantify the extent of stormwater control. Comparison in stormwater control is made between living roofs with three different substrate types at two different depths in a side-by-side comparison. No statistically significant differences in runoff response were found between the three substrate types tested. There was no statistically significant additional stormwater benefit found when increasing plot depth from 50-70mm. The overall cumulative retention efficiency of the Uo A living roof was 71.6%over the period of 23 October 2008 to 22 October 2009, where 1137.2 mm of rainfall was received. On an individual event basis, the living roof retained a median of 83.6%of rainfall received, with a median peak flow reduction per event of 93.2%. Living roof response cannot be linked to one factor alone; multiple parameters such as rain depth, rain intensity, climatic variables and antecedent dry days all play a role in influencing hydrologic response.
Year: 2010