Green roofs for stormwater retention and flowrate attenuation

Seminar by Denis M. O’Caroll, ARC Future Fellow and Associate Professor, School of Civil and Environmental Engineering, Water Research Laboratory, Connected Waters Initiative, UNSW Sydney.

Talk Abstract: Green roofs have been used for centuries to insulate buildings and beautify urban environments. European countries, especially Germany, have adopted green roofs use in modern buildings, helping raise awareness of their many potential benefits. Green roofs have been shown to: effectively reduce and filter stormwater thereby decreasing the burden on urban sewer systems; provide insulation and lower roof surface temperature leading to a decrease in building energy load; extend the life of a roof by decreasing the temperature fluctuations which cause roof damage; and to improve air quality by decreasing CO2 levels. Green roofs are becoming popular in North America as they are effective tools for managing stormwater runoff in urban areas. However, the implementation of green roofs in North American urban environments remains underused, in part due to a lack of climate appropriate green roof design guidelines.  A greater understanding of how green roofs perform with respect to fundamental stormwater management processes, such as stormwater retention and peak flow attenuation, is required. This study investigated the impact that differing climates have on the retention performance of three green roofs in three distinct Canadian climates (i.e., London, Calgary, and Halifax). Data were collected over 2.5 growing seasons.  The impact of climate on stormwater retention will be discussed in addition to the extent to which green roofs attenuate stormwater peak flow. 

About Dr. O'Caroll

Dr. O’Carroll is an Associate Professor in Civil and Environmental Engineering at UNSW Australia. He completed his BASc at the University of Ottawa, his MS at Clarkson University and his Ph.D. at the University of Michigan. Upon completion of his Ph.D. Dr. O’Carroll completed one postdoctoral fellowship at the University of Michigan and was awarded a NSERC postdoctoral award to complete a postdoctoral fellowship at the University of Toronto. He is an Associate Editor for Water Resources Research, the Vadose Zone Journal and the Journal of Contaminant Hydrology. He has ongoing research projects developing nanometals for contaminated site remediation, investigating the environmental fate and ecotoxicity of nanoparticles released from commercial products, improving the understanding of the fate of nonaqueous phase liquids in the subsurface and developing climate change mitigation measures in urban areas.

This talk was based on a paper by the same title authored by: Denis M. O’Carroll, Andrew W. Sims, Clare E. Robinson, Charles C. Smart, James A. Voogt, Geoffrey J. Haye, Jeremey T. Lundholm and Brandon Powers.