5 innovative water sensitive urban design initiatives

Water sensitive urban design (WSUD) mimics the natural water cycle by reusing stormwater in smart urban planning. It’s more than a buzzword — it’s a philosophy that is creating more liveable, resilient cities. 

During a recent Australian Water Association webinar, GHD Manager – Water Infrastructure Tim Anderson outlined the concept of WSUD.

“I think the movement behind water sensitive cities is a recognition that despite having a world-class water and wastewater system, we can do better to reduce our impact on the natural environment,” he said.

“The CRC for Water Sensitive Cities states that the vision of a water sensitive city has emerged as an aspirational concept, where water is managed in a way that meets a city's water needs while also supporting a city’s urban liveability, sustainability, productivity and resilience.

“Whether that be impacts on liveability like dry sports fields during the drought or rubbish floating in your favourite urban waterway, or more significant issues like flooding, over extraction and over use of resources, the water sensitive cities vision offers a toolkit to help us address some of these challenges.”

Here are five initiatives doing just that.

Paving the way for a smarter future

After the millennium drought, Brisbane City Council implemented its WaterSmart Strategy, aiming to minimise the impacts of urbanisation on the natural water cycle.

“An important part of WSUD is applying best practice stormwater management, which helps to maintain, protect and improve the health of our waterways,” the WaterSmart website states. 

“Left unmanaged, urban stormwater can pollute waterways, cause erosion, sedimentation and increase flooding.”

The city has promoted adoption of WSUD measures including stormwater harvesting, rainwater tanks and permeable pavements to improve water use efficiency. 

One project in Ipswich’s Queens Park sought to harvest water into the root systems of struggling poinciana trees and stop erosion of the public footpath. Porous PermaMulch overlaid on porous permeable paving allowed air and water to flow through the material to the soil below at a rate of over 1000 L/square metre/minute. 

“The water is now easily and quickly absorbed into the ground, watering the trees as opposed to running down the path to the storm water drain, taking debris with it,” according to the project website.

https://youtu.be/AUeknNgmIv4

Keeping an eye on stormwater

Stormwater runoff, and the litter, bacteria and sediments it picks up along the way can significantly damage waterways and the ecosystems that rely on them.

Tasmania’s Derwent Estuary Program put together a suite of initiatives to improve the quality of 13 major rivulets and over 270 pipes discharging stormwater to the estuary. 

These include:

• Developing and implementing soil and water management guidelines for building and construction sites.
• Securing grant funding and supporting construction of stormwater treatment systems, including passive treatment wetlands at Windermere Bay and Whitewater Creek.
• Developing a range of stormwater resources for local government and developers, including technical guidelines for Water Sensitive Urban Design.
• Monitoring and modelling stormwater quality to track changes in pollutant levels over time.

A simple recycling solution

Melbourne’s Edinburgh Gardens will save 20 ML of drinking water each year by capturing and distributing urban stormwater run-off to irrigate the parkland.

The water saved through the project, which was co-funded by City West Water and Yarra City Council, will meet most of the park’s irrigation needs by expanding on the existing stormwater harvesting scheme through installing a 1 ML below-ground storage tank and upgrading the existing pipelines and pumping infrastructure.

Yarra City Council Mayor Misha Coleman said local residents would benefit from keeping the green space as healthy as ever with a water sensitive urban design.

“The upgrades will also help us mitigate downstream flooding in the Fitzroy area, will reduce water pollution, and will contribute to Yarra’s ambitious water reduction targets,” she said.

Using stormwater to fight the heat

A world-first heat mitigation trial conducted by SA Water and Adelaide Airport found that using recycled stormwater to irrigate vegetative cover could lead to an air temperature reduction of over 3°C on hot days, when compared with non irrigated areas.

The project applied recycled water from SA Water’s nearby reuse scheme to four hectares of Lucerne 600 m south of the airport’s runway twice a week at night.

Temperature reduction is significant for airports, where flights can be grounded if the surface temperature gets too high.

SA Water’s Manager of Environmental Opportunities Greg Ingleton, who came up with the scheme, said the utility had shown the idea to airports in hot climates around the world, such as Abu Dhabi.

“By supporting green infrastructure and the intelligent use of water, we can cool urban areas and reduce the impact of heatwaves and climate change,” he said.

Legislative approach

In 2019, Victoria enshrined an Australian-first integrated water management framework into its planning provisions for almost all forms of urban development. 

The framework aims for “consistent and strategic collaboration within the water sector”, including water providers, local governments and catchment management authorities involved in land use planning. 

Strategies outlined by the government include focusing on infrastructure for drainage of water and wastewater, filtering of sediment and waste from stormwater prior to discharge from a site, and the integration of water into the landscape to facilitate cooling, local habitat improvements and provision of attractive and enjoyable spaces for the community to use.

Meredith Dobbie, a landscape architect and research fellow at Monash University, said that it was the first time that issues of thermal cooling, habitat diversity and amenity had been addressed in stormwater management. 

“Integrated water management is one way of increasing a city’s resilience to the effects of climate change and ensuring the ongoing survival of green spaces,” she said.