Wakerley Bioretention System
The Wakerley Bioretention System is an innovative application of both new and existing bioretention technology to treat urban stormwater runoff. Brisbane City Council commissioned AECOM Design + Planning (formerly Ecological Engineering), with the assistance of Verge Landscape Architects and FMG Consulting (civil engineers) to undertake the conceptual and detailed design of a constructed stormwater treatment system to manage the stormwater quality generated from new urban residential areas (87ha catchment) in Wakerley. AECOM’s Design + Planning conceptualised a novel bioretention system design that responded to the space limitations of the site (due to the adjacent protected remnant vegetation community) and the stormwater treatment targets.
Stormwater is pre-treated in a sedimentation pond and is then treated in the bioretention system through contact with dense vegetation, extended detention and filtration through the filter media. Larger stormwater flows are diverted around the system in a high-flow bypass channel to protect the bioretention system.
The landscape of the system compliments the surrounding vegetation communities and adds value by vegetating previously cleared land. The design also allows for passive recreation by way of a viewing ‘platform’ and extension of the regional bike path. This integrates the project site with the adjacent residential development and with the wider natural landscape.
- Design, construction and establishment timeframe 2005-2007
- Tilley Road, Wakerley (Brisbane, QLD)
- Total project capital cost for the Wakerley Bioretention System including the surrounding revegetation and landscaping works is in the vicinity of $1.35 million with approximately $567 000 attributed to Landscape works and $777 000 to civil works.
- City Design, Brisbane City Council
- Brisbane City Council
- Ecological Engineering (now AECOM), Verge Landscape Architects, FMG / Koukourou Engineering
- Brisbane City Works
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To design and construct a regional vegetated stormwater treatment system to treat runoff from new urban residential areas.
To incorporate opportunities for learning and the advancement of bioretention technology through the incorporation of saturated zones, and the ability to monitor the water quality of inflows and outflows. - A key challenge for large bioretention system such as this is achieving even flow distribution across the system surface. The Wakerley bioretention system accepts flows from a 78 ha urban residential catchment, which resulted in a total treatment surface area of 2865 m². To ensure the even distribution of flows over the bioretention treatment surface (filter media), the bioretention system was configured as three hydraulically separate cells.
- Close collaboration between the multidisciplinary project team ensured the stormwater treatment train integrated with the surrounding natural environment and the landscape character of the adjacent residential development while also providing opportunities for passive recreation and community education.
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In addition to providing treatment of urban stormwater runoff, the bioretention system is designed as a research facility to provide opportunities for learning and the advancement of bioretention technology. Some examples of this are:
• Different vegetation species and planting mixes of species were planted in the 3 separate cells to test their success within bioretention.
• One of the cells incorporates a saturated zone to test the benefit for nitrate removal via microbial denitrification.
• Infrastructure has been included in the within the bioretention systems to allow comprehensive monitoring of the system.
