-Press Release - 22 Jan 05

On the Ball: An Evolutionary Step in Environmentally Sensitive Canal Design.

Western Australia has successfully commenced Australia’s first canal habitat enhancement program, pushing the boundaries of canal design.

Canal estates in coastal areas rank among the most controversial of modern developments. Our historic disregard for ‘smelly coastal swamps’ and their valuable role in nature has led to their replacement with ‘more useful’ canal dwellings. We build and we learn - and now realise the error of our ways. Tighter regulations and better engineering now mean more environmentally thoughtful canals.

We have recently reached significant milestones in the evolution of canal estate design with the inclusion of environmentally sensitive features. The purpose built migratory wader bird roosts at Bribie Island’s (Qld) Pacific Harbour and the award winning preservation of wetlands at Mariners Cove (WA) are two good examples. We are now thinking outside the square and including the very natural qualities that attract many to the coast.

Yet we are still focused above the waterline and overlooking what lies beneath, which in the natural environment is intrinsically connected to what lies above. The next step in the evolution of the canal estate is to replace the impressive collection of straight, smooth walls and bottoms of canals with an environment that encourages a diversity of marine life. And if we retain natural wetlands or include purpose built natural areas, we need to remember that efforts may be wasted if adjacent aquatic habitat is inadequate to support the transfer of productivity.

There are three key methods of adding complexity and varied habitat: changing canal wall configuration, using alternative wall materials, and adding specifically designed concrete reef modules.

Two canal estates in the Peel region of WA have chosen the latter and are deploying concrete artificial reef modules known as ‘Reef Balls’ in their canals. Reef Balls are a patented hollow dome shaped module with numerous holes and complex surface texture, specifically designed to support marine life.

Their addition to the base of canal walls or under jetties adds significantly greater useable width and shelter that marine life can utilise to live and breed. They can also provide the added benefit of helping attenuate boat wash which can be magnified within canals.

Over 500,000 Reef Balls have now been deployed around the world but never before within Australian canals. The modules are being produced from imported moulds by not-for-profit group, Peel Region Fish Stocking & Management Association with funding provided by Port Bouvard Ltd, Cedar Woods Properties Ltd and Peel Development Commission. Volunteers underwent training in Reef Ball manufacture and deployment and have successfully deployed 40 modules in the canal estate. The group will monitor the effectiveness of the modules and expand the program in the future.

This is the beginning of a new era in canal design. With just a little extra thought and very few extra dollars, canals can become diverse communities and productive ecosystems that support local fisheries and increase recreational and financial value for residents. Into the future coastal engineering may include environmentally sensitive design of coastal structures, such as rock breakwaters, canal walls and bridge pilings, as a natural evolution in our understanding of the way in which the built environment interacts with the natural environment.

For more information contact: David Lennon, environmental consultant and Australian Reef Ball contractor, gmidavid@tpg.com.au

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Photo: key members of the Peel Region Fish Stocking & Management Assoc. with one of the Reef Balls being placed under a jetty to enhance diversity of habitat in Mariners Cove canals, WA.

Photo: Reef Ball being lowered by crane into corner of Port Bouvard canal, WA

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