What drives the uptake of WSUD?
At the State level in NSW there is no clear legislative mandate requiring specific and measurable stormwater objectives for urban development. Councils do however have a role to assess development and provide stormwater approvals under the EP&A Act and Local Government Act.
In the absence of State mandates and guidance, an understanding of locally meaningful drivers for WSUD are vital. Here are a just a few possible examples of local drivers for WSUD from our region.
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Driver: The benefits of healthy local waterway "assets" are recognised and understood.
Great Lakes Council understands that the Lakes system underpins the local economy and quality of life. The importance of the Lake's health was highlighted in the early 90s, when poor water quality shut down the local oyster industry, and reduced the level of seafood sold accross NSW.
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Driver: Evidence that the community (residents, businesses, primary industry) value and care about local waterway health.
Lake Macquarie City Council regularly conducts phone surveys of
residents to explore and document the community’s attitudes and behaviours around the management of the Lake. In 2009 81% of respondents indicated that, in general, they are concerned about environmental and sustainability issues affecting the Lake.
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Urban development increases the relative area of impervious surfaces in a catchment. Roads and carparks can account for 50% of land in urban areas2. This change significantly modifies the hydrology of urban areas. Less runoff infiltrates into the the ground. Instead, greater volumes of runoff flow at higher velocities across hard surfaces, collecting pollutants before draining into our waterways. This is a diffuse pollution problem. To better focus efforts it can help to identify priority waterways. These may be protected by law; have high environmental, social and/or economic values; or have a reasonable chance of recovery if catchment practices improve.
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Driver: The impacts that urbanisation is having or will have on the health of valued waterways is understood.
Great Lakes Shire Council has undertaken significant scientific modelling to understand and predict how the lake's ecology is impacted by what happens in the rural and residential catchments upstream. This modelling identified the amount of nutrients and sediment pollution that is likely to impact on waterway health.
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Driver: Priority waterways for protection are identified, and how their health can be influenced by upstream catchments is reasonably well understood.
Porters Creek Wetland, in Wyong Shire, is a State Significant (or 'SEPP 14') wetland. Council is setting objectives for urban development in catchments upstream of Porters Creek to reduce the negative impacts of development - by encouraging drainage systems that mimic the wetland's natural wetting and drying cycles. |
About 80% of Australians now live on a narrow coastal strip of land that is becoming increasingly urbanised. On average over all the seasons, these coastal urban areas are actually net exporters of water.1 Integrated Water Cycle Management seeks to 'drought proof' our suburbs and towns by employing a range of options for water supply - such as roofwater, harvested stormwater and wastewater recycling, treatment and reuse.
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Driver: Water Shortages, drought and the need for Climate Change 'resilience'.
During the 2006 drought a ban was placed on using potable water in swimming pools and outdoors on the NSW Central Coast. Wyong and Gosford Councils and their water authority have since 'drought proofed' a large number of public facilities. A number of these projects have linked the objective of protecting natural wetlands from 'overwatering' - by harvesting the stormwater upstream of these wetlands and reusing it on playing fields. The Mingara Sport and Recreation Club - left - is an example of one facility that practices water efficiency, roofwater and stormater harvesting, as well as onsite recycling. |
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Driver: The sum total of WSUD benefits are perceived to "stack up" against the 
costs.
A 'business case' analysed the costs and benefits of WSUD approaches to meet Queensland's proposed development targets for urban water. Prepared by the Water by Design team, SEQ. Find out more about this study.
Such studies identify the tangible and intangible costs and benefits of WSUD - that are experienced by public or private parties.
WSUD Benefits commonly cited in literature and studies 3 include:
- Avoided waterway rehabilitation costs.
- Prolonged 'useful life' of stormwater conveyance assets. Stormwater drains are less clogged with gross pollutants and sediment. Natural creeks in better condition to handle major storm flows without eroding -posing a risk to infrastructure, property and safety.
- Increased land value, locality 'branding' and marketability.
- Improved amenity for example, urban areas take better advantage of waterway corridors; 'greener' streets and reduced 'urban heat island' effects.
- Improved active and passive recreation, health and lifestyle, and social wellbeing through improved open spaces.
- Biodiversity and ecological benefits.
- Improved sustainability of primary industries, tourism and other businesses that rely on health waterways.
WSUD Costs across the lifecycle can include:
- Land aquisition costs for stormwater measures, reduced road reserve (if stormwater treatment measures result in restricted car park or footpath space).
- Device design, construction and establishment.
- Ongoing maintenance.
- Impact on nearby residents who may be affected by mosquitos if stormwater systems are not properaly designed, constructed nor maintained; or from temporary ponding during wet weather.
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REFERENCES:
1: Australian Government (2006), Australian State Of the Environment Report (National),
2: Environment Australia (2002), Introduction to Urban Stormwater Management in Australia
3: Taylor, A.C. (2005) Stormwater BMP Cost-Size Relationships, CRC for Catchment Hydrology, Monash
University.