UC makes breakthrough in green-planted roof research
October 21, 2013
The University of Canterbury (UC) has discovered green-planted roofs do not need to be irrigated in winter or summer to
thrive.
UC natural resources engineering researchers Dr Aisling O'Sullivan and Dr Tonny de Vries are investigating the benefits
of green roofs for the New Zealand built-environment.
``A team of two undergraduate honours civil engineering students have found the green roof engineered substrates hold
water for longer, which helps keep the plants alive in drier conditions.
``We can confirm our green roofs are living so well 18 months after being planted and without ever having been
irrigated. This coming summer will be exciting as it will be the second year of a summer without irrigation to test the
systems further.
``The team have completed some mathematical modelling using the green roofs to estimate the savings that can be gained
in stormwater management from green roofs as a source control technology.
``We expect to unearth some positive results. Our detailed monitoring of 18 months of systems grown in Christchurch has
enabled the effect of green roofs on water quantity and quality to be understood throughout a range of climatic
conditions,’’ Dr O’Sullivan says.
The green-roofs have recently received the UC sustainability gold prize judged by a panel of external parties.
The judges commented that her group's research (including the green roofs) have left a formidable legacy both on and off
campus. The award recognised outstanding research and leadership with a particular focus on Okeover Stream, a special
treasure flowing through the campus’s ecological corridor.
More than 200 civil and natural resources engineering students use the stream in their class work each year. Secondary
school students have visited the stream and Dr O’Sullivan’s group has received significant Christchurch City Council
funding to develop a research park approach to test storm water solutions to provide data for new storm water consents.
``Christchurch’s rebuilding plans strongly encourage low impact designs, including green roof systems, and UC has
established a green roofed building with different types of plants on campus and different soil depths to help guide new
designs for Christchurch,’’ Dr O’Sullivan says.
Engineered green roofs are becoming common in New Zealand as they offer multiple benefits including stormwater control.
They have been installed on Waitakere’s Civic Building in Auckland, at the Remarkables Primary School in Queenstown, the
NZI Centre in Auckland, Pipitea Plaza in Wellington and many other sites in New Zealand. Dr O'Sullivan's systems at UC
are a first for Canterbury.
The roofs reduce energy consumption and improve local air quality by trapping air particles and smog and are most
important for storm water management by reducing peak flow rates and volumes of stormwater.
Photo, from left to right: Dr Aisling O’Sullivan, Dr Daniel Wicke and Dr Tom Cochrane (below) with their real-time water
quality monitoring system at UC.
ENDS