Above: Photo from the Central Park sales building.
Yesterday I attended a forum on the use of green walls and roofs in Sydney. The forum was part of the Sydney Design series and put on by the Powerhouse Museum and City of Sydney Council. This was an examination of the issues associated with city living, the need for sustainability to be considered in city design, and the solutions offered by green roofs and walls. The presenters were Sacha Coles, a director at landscape architecture firm ASPECT Studios, professor Stuart White, Director of the Institute for Sustainable Futures, and Lucy Sharman, Senior Project Officer Green Roofs and Walls, City of Sydney. I will attempt to do justice to their ideas.
What is a green roof?
Structurally a green roof consists of waterproofing, a membrane, soil and plants. To be considered as a "green roof" over 30% of the surface must be covered in vegetation.
What is a green wall?
The definition of a green wall is less restrictive. It can be something being grown up a wall (such as a vine), planter boxes next to a wall with plants reaching up and along the wall, or a vertical forest installation such as the work of Patrick Blanc.
Urbanisation and sustainability
An increasing proportion of people live in the world's cities. Initially we can see this as exacerbating the world's environmental problems with issues of housing demands, increased pressure on food supply from the farmland on the periphery of the city, photochemical smog, loss of open space, storm water pollution, and a raft of other problems. However, we need to think of cities as centres of sustainability. The increased density associated with city living can actually mean that cities can provide viable sustainability solutions. Increased densities result in decreased car dependency, easier transport solutions, less need to lay new roads, electrical lines and water (unlike new developments in new suburban areas on the outskirts of cities) . Architectural innovations such as green walls and roofs can provide cities with the ability to improve their capacity to feed themselves, filter their water and waste, and moderate temperatures associated with the urban heat island effect. Globally some cities are already making a grey to green transition. These include Chicago, Basel, London, Stuttgart.
How can governments encourage GRW?
Some cities around the world have begun introducing incentive program's to encourage GRW. These include:
- fee reductions
- reduced storm water & levee fees
- density bonuses
- education programs
- technical support and advice
- mandatory legislation
In Sydney there are still some barriers to widespread use of GRW. It is still quite poorly understood, there are technical issues and cost barriers, and industry is not quick to embrace it.
In the City of Sydney currently:
27 green walls
53 green roofs in Sydney
At least one DA each week which incorporates a green wall or roof.
Documents from the City of Sydney Council that support sustainability and Green roof and walls developments.
- Sydney 2030
- Greening Sydney Plan 2012
- Green Roofs and Walls Strategy
Check out other upcoming events at PowerHouse Museum as part of Sydney Design 2013.
Relevance to the classroom
So how can this information be integrated into the classroom? After all, this blog is supposed to be about teaching. If you are using Sydney as your large city case study in Year 12 Geography Urban Places, this fits in perfectly. I'm considering looking at Central Park specifically and how this development gives us some hope of the improved sustainability of development in the city. I will also tie it in with a number of other examples of development around the city. My previous blog about the Inner West Light Rail extension fits in well with this topic too. Click for lessons on Sustainability in Sydney for Yr 12.
There is scope to look at cities and sustainability in the broad sense in Year 11 Geography when you are examining the Population topic and looking at social, economic and environmental impacts of population growth. This also ties in with some of the presentations at the Australian Geography Teachers Association Conference in January from Professor Peter Newman about the transformation of Cheonggyecheon River in Seoul and Singapore as a biophyllic city.
You could also tie this in with Year 10 Geography Australia's Future as part of a broader discussion on sustainable development in Australia.
Why not create a vertical garden in your classroom or somewhere in your school? Flower Power currently sell a frame and planters to create your own vertical garden. It is only about 1m by 1m and will cost about $300 to set up but it would be a great way to attract some attention to your faculty or even your school depending on the scale. You may even be able to access a grant from your local council.
Deputy Principal at a Sydney high school. Coordinating author of the new Geoactive book series.
Student resource sites: