Brisbane City Council has demonstrated that raingardens (bioretention systems) can be implemented on a range of scales through the installation of raingardens at Wakerley, Bridgeman Downs, McDowall and Willawong.
The Wakerley raingarden on Tilley Road is currently the largest bioretention system in Australia.
This bioretention system accepts flows from an 87 hectare urban residential catchment and has a total filter area of 3000 square metres. It can treat one cubic metre of stormwater each second.
The bioretention process is also at work on a smaller scale in the residential areas of McDowall and Bridgeman Downs. Traffic calming devices in these areas have been retrofitted to double as bioretention systems, which capture stormwater runoff from the road. Treated stormwater then drains directly into nearby stormwater gullies and into local waterways.
Raingardens in the home
Raingardens can also be replicated at home and be as big or small as your backyard and budget allows.
Bardon resident Anne Simi built a raingarden in her backyard to treat the overflow from her rainwater tank before it flows into a nearby creek.
Water runs from our roof into our tank and any overflow will now run into our raingarden, Anne said.
The raingarden will slow the water down and decrease erosion, as well as depositing less polluted water into the local waterway.
The raingarden was a weekend task for the Simis' family, who took around six hours to build the 1.6 square metre structure from the ground up.
Once we had the supplies it was simply a matter of following a number of simple steps to put it all together, she said.
The tools we needed were a level, circular saw and a drill, and it cost around $200 for the materials such as sleepers, soil, gravel and plumbing supplies. It was easy and fun to build and every little bit helps to improve the health of our local waterways and Moreton Bay.
There are two demonstration raingardens at Downfall Creek Environmental Centre and at the Boondall Wetlands Environmental Centre (pictured above).