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project introduction

CASE STUDY # 1

Water Sensitive Urban Design (WSUD) Demonstration Precinct

location: Sunshine Coast Regional Council

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Water has become an increasingly precious resource in Australia's urban areas. When we build cities and towns we significantly alter natural hydrological cycles and ecological processes.  Water is imported from our water supply catchments and discharged through the sewerage system back into our rivers and oceans. 

Water Sensitive Urban Design (WSUD) has been around since the early 1990s, and seeks to restore natural hydrological cycles within urban and suburban developments.  The main aim of WSUD is to reduce the amount of run-off, sediments and nutrients entering our river systems.  It also makes water available in the landscape for plants and wildlife.

It’s not only towns like Canberra that have been feeling the water pinch.  In coastal Queensland, is increasing development pressure accompanied by ongoing drought, mean that smarter water management has become essential.  The Sunshine Coast Regional Council, has developed a WSUD demonstration site: the Cotton Tree WSUD Precinct.  The site is within walking distance of the Maroochy River which spills nearby into the Pacific Ocean. 

Maroochy River like many of Australia’s rivers has been in decline.  Much of the river degradation is due to increased stormwater run-off from surrounding developments. 

The Cotton Tree site has two main components – a new car park of 100 bays demonstrating a range of swale and pavement types and an existing public library retrofitted to harvest rainwater.  The project has a number of measurable benefits - it educates the development and construction industry as well as council staff by showcasing new products and construction techniques; it demonstrates a range of swale types which can be applied in different settings; and it contributes to improving the health of local waterways. 

At the Maroochydore library three different styles of tanks (conventional rounded tanks plus a slimline plastic tank) were installed and connected to downpipes.  Slimline tanks show its possible that almost any residence can fit in some sort of rainwater harvesting on restricted or narrow sites. The water rainwater is used to supply water for cisterns in the nearby public toilets and in an administration building. 

Overflow from the rainwater tanks and nearby paving is directed into a rain garden detention basin.  It’s been planted with locally occurring native plants like rushes and palms which can cope with fluctuations in water supply.  This garden creates an attractive leafy setting for the library building whilst requiring no mains irrigation.  The rain garden also performs an important hydrologic function by slowing down the water flow and removing sediments and nutrients, which would otherwise find their way quickly into the Maroochy River.  In heavy rainfall events (every 1 in 2 years) excess water is directed to the stormwater drain so surrounding infrastructure is not flooded. 

The once uninspiring gravel car park was converted into a model of wsud.  The council design team have been involved in the concept, design and implementation of the project.  This cradle to grave process has ensured that both the car park and the library retrofit represented good value for money and the environmental requirements were not compromised.  

Five different types of permeable pavement products have been trialled within the precinct: including Boral Hydrapave, Hanson Eco Monarch pavers, Hanson Grass pavers, Permapave Permeable Pavers and Atlantis Drainage Cells.  Products will be monitored to assess their ongoing performance.  A range of swales types were introduced including rock infiltration, vegetated bio-retention, vegetated infiltration, grass and pebble mulch bio-retention.

In keeping with the environmental spirit of the project, care was taken to select landscape materials, wherever possible with minimum embodied energy.  Bollards are made of recycled plastic, or recycled timber, quarried boulders and gravel were used over local river products, mulch was sourced from recycled green waste and the Atlantis drainage cells are made from recycled polypropolyne.

The concept of WSUD has been embraced by the ACT government. 

In 2006, the ACT Planning and Land Authority produced the draft Water Sensitive Urban Design: guidelines for sustainable development in Canberra.  The aims of the guidelines were multiple: to reduce the reliance on mains water, to optimise opportunities for water reuse and reduce stormwater runoff and associate pollutants to pre-development levels.  The draft would have required new dwellings to demonstrate a 40% reduction in the amount of water used on the site. 

The relatively simple and inexpensive water harvesting retrofit of the Maroochydore Library serves as a model for Canberra’s existing public buildings.  Public libraries and schools could easily adopt these measures, helping reduce the overall water use of these facilities and reducing their impact on local catchments.

Similarly, retrofitting residential dwellings is possible.  Ian and Helen Lawrence have managed to reduce their reliance on town water in their Higgins garden by around 90% by applying a range of WSUD principles.  Using rainwater tanks, a simple grey water system, permeable paving, swales, a pond and appropriately selected plants they have created a garden that puts less pressure on the local catchment. 

So while we have some good built public examples of WSUD in Canberra they tend to be isolated and their intent is only clear to those in-the-know.  Designed by landscape architect, Jamie Dawson of Envirolinks is the O’Connor wetland and the landscape treatment at the Innovation Centre, University of Canberra; improvements at the Holt Shopping Centre by Landscape Architects, Harris Hobbs; Norgrove Park by the landscape architecture practice, Red Box and a number of other examples within greenfields developments. 

What we lack is a demonstration site which displays the whole box and dice.  The site should be accompanied by interpretive signage explaining the values of WSUD and could be used by school groups as part of environmental education. 

The proposed urban development of Eastlake, touted as a model for the best Australia has to offer in terms of sustainable design, is an ideal place to locate a demonstration site.  Nearby is Norgrove Park, designed to reduce and filter run-off from the Kingston Foreshore Development.  Over a short period the vegetation has grown incredibly quickly to create anaesthetically pleasing parkland with strong ecological credentials. 

It is essential that water is handled well at the proposed Eastlake in order to protect the iconic Lake Burley Griffin and the nearby significant Jerrabomberra wetlands. 


 

WSUD WSUD.org - Resources and examples, including sustainable water challenge projects and ither WSUD case studies in NSW and Australia.
South East Queensland:
Water by design

WSUD Key Principles

Melbourne Water

WSUD Case Studies

Melbourne Water

WSUD planning and policy

 

WSUD Guidelines
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