Sustainable Stormwater Management
Have you wondered why new housing sub-divisions have water features such as lakes in them? Examples from around Brisbane include Springfield Lakes, Northlakes and Forest Lake. The lakes are generally part of a network of landscape features built throughout the new suburbs to manage stormwater runoff. While the lakes have many values and uses, among these is the prevention and treatment of stormwater pollution beyond the development site in downstream waterways.
Water-sensitive urban design (WSUD)
The creation of artificial lakes and wetlands in new urban developments is part of a new design concept referred to as ‘water-sensitive urban design' (WSUD).
The traditional approach to urban stormwater management has been to collect runoff and channel it within closed underground pipes and discharge the channelled water into natural receiving waterways with little, if any, treatment prior to discharge.
The basic aim of WSUD is to protect and enhance our natural waterways in urban catchments by reducing pollution in stormwater runoff. Additionally, recycling the water within our properties is seen as ecologically responsible and hopefully a cost-effective use of a scarce resource.
Water-Sensitive Urban Design re-defines water management and conservation in a practical way. Designing new housing and other developments to incorporate WSUD is about ensuring that water, as a resource, is used as efficiently as possible. So instead of simply removing water from a site without treatment, and creating water quality and quantity problems downstream, water should be stored, reused and treated at every possible opportunity. This helps to create more sustainable developments.
Landscape elements of WSUD, which feature in many new developments include:
- Grass swales (drains)
- Bio-retention drains
- Treatment wetlands (artificially constructed)
- On-site storage systems (above and below ground storage tanks)
- Porous or permeable paving in car parks
The different elements of water-sensitive urban design are usually integrated throughout the development area (often more than one allotment or a new suburb) in a combination known as a 'treatment train'. This involves constructing stormwater treatment devices at locations where the stormwater is collected, channelled and discharged. The selection of treatment options should be based on the removal of pollutants from the surrounding land. Pollutants may include sediment, hydrocarbons, organic materials, heavy metals, pesticides or nutrients (from fertilisers).
WSUD can be implemented in individual properties or across larger sub-divided land.
Whilst WSUD is not yet practiced widely in Queensland, the Upper Parramatta River Catchment Trust in New South Wales has worked with a local land developer to demonstrate WSUD principles at work. One particular project has successfully installed WSUD components in a house lot within a housing display village in western Sydney.
The current challenge in Queensland is for Councils to work with developers, researchers and the State Government to implement WSUD and sustainable stormwater management as a core feature of all new developments.
Healthy waterways has developed a webpage to assist industry and government to bring together knowledge, experiences and expertise to improve the adoption of water sensitive urban design in South East Queensland. For more information please visit Water by design.