Across Australia, councils are investing significant time and resources toward improving green infrastructure in their municipality.
As the Australian market for green infrastructure is young and the industry is relatively juvenile, it is not always easy to see where councils can achieve the greatest effect in this area. Lessons learned in other countries can be invaluable, but at the same time, not all of these pertain to our market and industry. It is important to be selective in applying lessons from other countries and to adapt those lessons to the specific conditions of the Australian industry.
We know there are six key ways in which local government can foster and support the development of effective green infrastructure on an urban scale. What are some additional actions that councils can take, both to communicate support for green infrastructure in their municipality, and facilitate the broader development of the Australian industry?
The single most effective action any council can take to catalyse more green infrastructure on privately-owned buildings is for the Planning Department to state clearly and accessibly whether they have specific planning requirements for green infrastructure.
It is important that this information is both clear and accessible to the public, as this saves much time for architects and developers, and helps to avoid unnecessary confusion and uncertainty.
Where councils do not have specific requirements, a clear, accessible statement to this effect would also save much time for architects and developers, and would allay concerns that lead them to omit green infrastructure simply on account of uncertainty.
Incentives can be a powerful means of stimulating the uptake of green infrastructure, including local and international examples where local government has used this strategy to good effect. However, while many such incentives focus on providing short-term financial support for the construction of green infrastructure, there is also a significant opportunity for local government to use incentives to facilitate the longer term transformation of the property industry.
Instead of creating incentives for developers to include green infrastructure in their developments, local government should require developers to design commercial high rise buildings that are 'green infrastructure-ready.' Such an approach would go a long way toward reducing the high retrofit costs of structural engineering that are often associated with green infrastructure. This would also steer the development of the property industry so that more buildings are equipped to support the projected expansion of green infrastructure.
There are a number of ways in which local government could support the development of commercial high rise buildings that are green infrastructure ready. Some examples include:
- For green walls and vertical gardens, requirements might include that a minimum percentage of all walls within 15 metres of the ground are designed with sufficient strength to support the addition of vegetation. Note that the weight of green walls varies significantly according to the system and horticultural design. Green facades can be accommodated in Australia for as low a weight loading capacity as 20 kilograms per square metre. The weight loading capacity required for a green wall system, in which plants are planted into the wall, is likely to evolve as the industry innovates. At present, a weight loading capacity of 80 kilograms per square metre is, roughly speaking, the entry requirement in Australian conditions. Meanwhile, 190 kilograms per square metre enables a greater range of vegetated options currently on the market.
- For green roofs, new developments might require that a minimum percentage of roof space within a set height (for example, four to 15 levels) be designed with sufficient strength to support the addition of new storeys or the development of a rooftop garden. As with green walls, the weight of rooftop gardens varies considerably according to design and purpose. At present, a minimum weight loading capacity of 80 kilograms per square metre is required to support green roof systems in Australia.
- In addition, to be “green roof ready” developers should install 1.2-metre balustrades during the building construction phase, when the associated costs of installation are comparatively low. This saves significant costs later should building owners or tenants wish to install green infrastructure after the building is complete.
- For both forms of green infrastructure, consideration should be given to access and maintenance, both during the retrofit stage, and for ongoing use and management. Access points and maintenance elevators should therefore be of a suitable size to enable the transport of construction and waste materials to and from the area.
One of the advantages of encouraging commercial high rise buildings to be 'green infrastructure ready' is that it will not only support the expanded application of green infrastructure in the future, and reduce the cost of installation, but it will also improve the overall value of buildings, and the ability of developers to attract tenants.
For many local governments, the development of such planning incentives is a long term project. For councils wishing to take some quick action, we recommend focusing on actions relating to planning, as these will have immediate impact. For ambitious councils ready to do more, we recommend some additional valuable actions below.
Set concrete council targets for the area of green infrastructure to be created in each of your target building types (public sector buildings and private sector buildings) as well as for the percentage of that area to be native species.
Take a strategic approach to creating standards
Focus first on creating an environment in which green infrastructure flourishes, then work on developing stand alone standards for green infrastructure. Standards can stifle innovation and this would be unfortunate at the current young stage of the growth of the industry in Australia.
There is a great opportunity right now for councils, planners, and industry stakeholders to work together, and direct the growth and quality of the Australian green infrastructure industry.
Co-written with Pip Hildebrand