green roofs for a wide brown land - the university of melbourne
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Green Roofs for A Wide Brown Land - the University of MelbourneTRANSCRIPT
Green roofs for a wide brown land?-Research required to develop a successful Australian industry
Nicholas S.G. Williams, John P Rayner and Kirsten J Raynor
Department of Resource Management and GeographyGraduate School of Land and Environment
The University of Melbourne
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
Green Roofs are SexyIn recent months there have been media stories in:• The Age• Sydney Morning Herald• Daily Telegraph• Horticulture Australia• Gardening Australia• Radio 2SER• Radio National: By Design• Moreland Leader• Queensland Property and Lifestyle magazine • Business Week
Highrise horticulture ... the rooftop garden at M Central in Pyrmont.Photo: Lee Besford SMH
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
Most Australian examples are intensive green roofs
Private home Sydney. Photo: Gardening Australia
Converted car park, Sydney. Photo: Gardening Australia
30 cm + substrate depth
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
Marine Discovery Centre, Queenscliff,
Most Australian examples are intensive green roofs
Crown CasinoMelbourne
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
• relatively nutrient rich, deep substrate (> 30 cm)
• allows for establishment of greater range of plants: trees, shrubs and conventional lawns.
• require high level of maintenance, regular irrigation and applications of fertiliser
• weight can be considerable requiring substantial reinforcement of an existing roof or extra building structural support
• Therefore $$$$ and difficult to retrofit
Intensive Green Roofs
Freshwater Place, Melbourne (Photo: Fytogreen)
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
• Shallow, low-nutrient light substrates 2-15 cm deep
• low maintenance, usually no irrigation or fertilisation (may be required initially)
• Potentially provide greater biodiversity benefits than intensive roofs, - ‘Ecoroofs’
• planted with, or colonised by, mosses, succulents, some wild flowers and grasses
• Few (None?) in Australia
Very Few Extensive Green Roofs
Semi-extensive green roof on CH2 building, Melbourne
Substrate 20-29 cm deep
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
Extensive vs Intensive
In North America, most of industry growth is for extensive or semi intensive green roofs
• Overall 30 % industry growth in 2007 • Number of extensive green roofs
increased by 40% in 2007• Number of intensive green roofs
decreased by 247% in 2007
Green Roof Industry Survey 2007
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
Why are there no extensive green roofs in Australia?
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
• A major barrier is the lack scientific data available to evaluate their applicability to Australian conditions.
Why are there no extensive green roofs in Australia?
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
• A major barrier is the lack scientific data available to evaluate their applicability to Australian conditions.
• Relying on northern hemisphere experience and technology is problematic due to significant differences in rainfall, temperature, available substrates and vegetation.
Why are there no extensive green roofs in Australia?
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
• A major barrier is the lack scientific data available to evaluate their applicability to Australian conditions.
• Relying on northern hemisphere experience and technology is problematic due to significant differences in rainfall, temperature, available substrates and vegetation.
• This may introduce unacceptable levels of risk and unnecessary expense to projects
Why are there no extensive green roofs in Australia?
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
• A major barrier is the lack scientific data available to evaluate their applicability to Australian conditions.
• Relying on northern hemisphere experience and technology is problematic due to significant differences in rainfall, temperature, available substrates and vegetation.
• This may introduce unacceptable levels of risk and unnecessary expense to projects
• Basic research is needed to objectively evaluate the performance, cost and environmental benefits of green roofs in Australia
Why are there no extensive green roofs in Australia?
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008 http://www.greenroofmaps.com/
Indicative World distribution of Green roofs
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
http://ag.arizona.edu/~lmilich/pe.html
The Australian Climate is different
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
International Green Roof Research
• Europe: 30-40 years• Nth America: 15-20 years• United Kingdom: 10-12 years• New Zealand: 3-4 yearsMany universities have independent green roof
research and testing facilities– University of Sheffield http://www.thegreenroofcentre.co.uk/index.html
– Michigan State http://www.hrt.msu.edu/greenroof/
– BCIT http://commons.bcit.ca/greenroof/
– North Carolina State http://www.bae.ncsu.edu/greenroofs/– Penn State http://hortweb.cas.psu.edu/research/greenroofcenter/
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
• Europe: 30-40 years• Nth America: 15-20 years• United Kingdom: 10-12 years• New Zealand: 3-4 yearsMany universities have independent green roof
research and testing facilities– University of Sheffield http://www.thegreenroofcentre.co.uk/index.html
– Michigan State http://www.hrt.msu.edu/greenroof/
– BCIT http://commons.bcit.ca/greenroof/
– North Carolina State http://www.bae.ncsu.edu/greenroofs/– Penn State http://hortweb.cas.psu.edu/research/greenroofcenter/
International Green Roof Research
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
University Research Facilities
• Replicated green roof modules or experimental plots
• Monitored for runoff quantity and quality, plant performance, energy use
• Funded by green roof component suppliers, government or companies wanting to build a green roof
• Establishing facilities at University of Melbourne, Burnley Campus
Penn State University
Oregon State University
University of Sheffield
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
Key Questions – Substrates
• Northern hemisphere substrates are well established but transport costs and materials differences necessitate that local substrates be developed.
• Unlike the green roof industry in North America and Europe, the few Australian proprietary products available have not been independently tested.
• May need to develop different mixes for different locations based on availability and cost
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
Key Questions – Substrates
• What substrates are available?• How do various substrate materials and
mixes perform under Australian roof conditions?– Temperatures can be as high as 90 C
• What depth of substrates are required for plants in the Australian climate?
• What are the lifecycle costs (sustainability) of substrate components
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
Key Questions - Plants• In temperate Northern hemisphere sedum
species are typically planted on extensive green roofs. – Collapse and die in extended periods of hot
weather– may not be suitable for Mediterranean or sub-
tropical climates in Australia’s major cities• Very little is known about the suitability of
Australian plants for green roofs. • Overseas interest in potential of drought
adapted Australian species.
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
Key Questions - Plants• Are there native plants that will survive on
extensive green roofs in Australian climates• Or do they require supplementary irrigation? • What is the minimum depth of substrate
required for survival?• What is the performance of Australian plants
relative to species used in the Northern Hemisphere?
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
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Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
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Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
More likely to be a Brown Roof?
Brenneisen S. 2006. Space for Urban Wildlife: Designing Green Roofs as Habitats in Switzerland. Urban Habitats 4: 27-36.
Kangaroo and Wallaby grasses with everlastings
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
• What are the stormwater volume and peak flow reductions in Australian climate conditions?
• How does this vary with substrate depth and planting palette?
• How do various substrates affect water runoff quality– Some mixes / components may leach N
• Can we use grey water on green roofs?
Key Questions - Water
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
• What is the potential impact on building energy performance
• Can green roofs cool the urban landscape?– providing 50 % green roof cover in New York
would lead to an average 0.1-0.8°C reduction in surface temperatures.
– for every 1°C reduction 495 million kWh saved– Will only work if irrigated- can’t use potable H2O
• What are the full environmental costs and benefits of different types of green roofs over their lifecycle?
Key Questions – Energy and lifecycle
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
Green Roof Research @The University of Melbourne
• Established a 20m2 experimental extensive green roof at the Burnley Campus
Using it to:1. Select plants that will survive and look good
in Australian climatic conditions2. Develop a locally produced light weight
substrate3. Investigate the effect of the green roof on
building energy budgets
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
• Investigating the drought tolerance of selected succulents, grasses and herbs
• Evaluating the properties of substrate components and mixes
• Determining the effect of recycled water on green roof substrates
Green Roof Research @The University of Melbourne
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008 Source:Zinco Planning Guide, 6th edition
• Green Roof system donated by ZinCo
• Used the FloraDrain40 system
• 125 mm of substrate
Green Roof Research @The University of Melbourne
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
125 mm
• Green Roof system was donated by ZinCo
• Used the FloraDrain40 system
• 125 mm of substrate 40 mm
Source:Zinco Planning Guide, 6th edition
Green Roof Research @The University of Melbourne
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
Root resistant water proofing
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
Fitting eaves to frame
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
Rolling out protection layer
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
Adding drainage layer
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
• Adding substrate and initial planting mid July
• Need to finalise plant selection• 10 individuals of 32 species• 20 cm plant spacing• Upright succulents, herbs
spreading succulents and grasses in separate quadrants
• Irrigation to establish only
Green Roof Research @The University of Melbourne
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
• Attractive• High tolerance to light• High ‘drought’ tolerance• Robust and moderate to high vigour• Easily maintained• Tolerate seasonal water logging?• Possum proof? • Available
Plant Selection Criteria
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
Habitat Templates
Gibber Chenopod ShrublandsImage: Rob Jung
Alpine rocky slopes
Native grasslands. Photo Georgia Garrard
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
Potential Plant Species
Lomandra multiflora subsp. dura
Wallaby Grasses(Austrodanthonia sp)
Rounded Noon Flower(Disphyma crassifolium)
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
Enchylaenatomentosa
Potential Plant Species
Sedum mexicanumRhodanthe floribunda
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
Pigface (Carpobrotusrossii)
Blue Chalk Sticks(Kleinia mandraliscae)
Dianellarevoluta Phormium
‘Thumbelina’
Potential Plant Species
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
Pigface (Carpobrotusrossii)
Blue Chalk Sticks(Kleinia mandraliscae)
Dianellarevoluta Phormium
‘Thumbelina’
Potential Plant Species
XX
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Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008 Semi-intensive green roof @ CH2. Media 20-29 cm deep
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
CH2 East Core Roof – February 2008
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
Conclusions
• Extensive green roofs have great potential as a climate change adaptation strategy– Less expensive– More easily retrofitted
• Few extensive green roofs in Australia• Many candidate native plant species• Need research for Australian conditions
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
Conclusions
• Extensive green roofs have great potential as a climate change adaptation strategy– Less expensive– More easily retrofitted
• Few extensive green roofs in Australia• Many candidate native plant species• Need research for Australian conditions• Hopefully our work we can help fill this
information gap
Dr Nick Williams, Melbourne School of Land & Environment Green Roofs Australia Brisbane June 2008
Acknowledgements
• John and Kirsten• Funding provided by The University of
Melbourne-CSIRO Collaborative grant scheme
• Materials provided by ZinCO• Peter May• Ross Payne