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News Building the case for green infrastructure


Urban sustainability has emerged as one of the defining challenges of the 21st century. One of the many questions it poses is how can the infrastructure of a city be sustained, particularly in the face of population growth, climate change and increasing consumption of non-renewable resources.


Much of the focus within the urban sustainability debate has been around built or 'grey' infrastructure such as housing, transportation systems and utility services. However, the sustainability of 'green' infrastructure within our cities is equally as important in maintaining our quality of life.


Green infrastructure was a term coined in the US in 1999, but it has its roots in US planning and conservation efforts over 150 years ago. It was originally conceived as an interconnected network of parks, waterways and green spaces that support native wildlife, maintain natural ecological processes and contribute to people's quality of life.


A green infrastructure approach is now seen as a means of countering some of the adverse environmental impacts of urban development and reconnecting people to the natural environment. More recently, green infrastructure is being applied to urban stormwater management.


Over the last two decades, both the public and private sector in Australia have pursued a green infrastructure approach in all but name, to meet environmental objectives. This has involved protecting and rehabilitating existing natural assets such as creeks, wetlands and bushland reserves, as well as pursuing water sensitive urban design (WSUD) in both greenfield and urban retrofit situations.


Yet hundreds of millions of dollars more will need to be allocated for the construction and maintenance of green infrastructure if we are to see any improvement in environmental indicators, including improved water quality, reduced flood risk, reduced potable water consumption, restored waterways and increased biodiversity and amenity.


Although the planning and management of infrastructure assets is becoming increasingly sophisticated, it is only relatively recently that green infrastructure has been considered as important as traditional built infrastructure. Asset managers are now starting to contemplate the long-term investment required in green infrastructure, and to adopt a more strategic approach for planning, construction, maintenance and renewal of such assets.


For instance, the Sydney Metropolitan Catchment Management Authority (SMCMA), through the Botany Bay Water Quality Improvement Program, has undertaken an extensive analysis of the investment required to implement green infrastructure in the catchments to improve the ecological health of the Georges River, Cooks River and Botany Bay. It has a positive message of how green infrastructure can be applied at a variety of scales within the public and private domain to achieve multiple social and environmental benefits.


We're also seeing a new integrated planning and reporting framework under which many local councils, particularly in western Sydney and the Hunter region, are updating their asset management systems to incorporate green infrastructure. Challenges are arising, however, around how traditional asset management philosophies can be applied to infrastructure that serves multiple purposes (such as a raingarden) or appreciates in value over time (such as a street tree).


This work also highlights the issue that, as with built infrastructure, existing funding sources may not be sufficient for the implementation, maintenance and renewal of natural assets. Disparities in the level of infrastructure investment between greenfield developments and urban retrofit situations also raises serious questions around environmental justice or 'green equity'.


This work reveals the need for improved integration between stormwater engineers, asset managers, environmental professionals and finance officers.


Although it may be widely accepted that having a clean, green environment is essential for quality of life, little work has been done to place a monetary value on the social, environmental and economic benefits of green infrastructure. As such, the business case for investing in and maintaining green infrastructure has not been developed to the same level of detail as for built infrastructure.


This lack of detail is now being addressed by Monash University as part of the Cities as Water Supply Catchments national research program. Drawing from the field of environmental economics, this research is attempting to show how the benefits of green infrastructure – better water quality, improved microclimate, reduced potable water consumption and more – can be quantified and used within typical economic assessments such as benefit cost analyses. This will be invaluable in helping promote green infrastructure to our political leaders and the wider community.


Unlike for built assets, there have been few forums at which to discuss the emerging issues around green infrastructure. In recognition of this, the NSW Stormwater Industry Association in partnership with Total Earth Care, is offering a seminar on the topic of green infrastructure and natural asset management next Tuesday (November 8) in Parramatta. Contact Peta Freeman at GEMS Event Management on (02) 9744 5252 or This e-mail address is being protected from spambots. You need JavaScript enabled to view it .