Application of New Bioretention Technologies to a Regional Scale Bioretention Basin in Brisbane

Bioretention systems are a relatively new technology in stormwater treatment and hence there is limited data available to define the performance of bioretention systems, particularly in Australia. While the application of bioretention systems has become common place, few are designed to allow for performance testing and long term monitoring. This paper discusses the application of a 2865m{2} bioretention basin in Brisbane designed to treat stormwater runoff from an 87ha residential catchment but also specifically designed to allow testing and monitoring of new bioretention technology. The system has been designed with three hydraulically separate filtration cells, each with a slightly different sub-surface drainage configuration and vegetation specification. One of the cells incorporates a continuously submerged anaerobic zone to test the benefit for nitrate removal via microbial denitrification. This new technology in nitrate removal is based on research from the University of Maryland and was developed to improve the nitrate removal performance of bioretention systems. Structural elements have been incorporated into the design to allow for ongoing water quality monitoring. The design of dual function bioretention systems that are fully functional as stormwater treatment systems but also include structural elements to allow testing and monitoring will provide opportunities for learning and the advancement of bioretention technology.