Abstract
In the past, swales have been shown to be very effective in treating urban stormwater runoff. The sediment removal processes of swales, in particular, have been shown to be consistent and reliable compared to the removal of other stormwater pollutants. Permeable pavements have also been shown to be very effective stormwater treatment devices that can significantly reduce surface runoff and improve the quality of stormwater runoff in urban areas, as well as providing stormwater attenuation functions. However, the potential problems with sediment clogging and consequent maintenance requirements have been identified as the main barriers to more widespread adoption of permeable pavements in urban developments. A current study at the University of the Sunshine Coast is investigating the effectiveness of using grass swales as pre-treatment devices for permeable pavements in order to reduce clogging effects and prolong the effective lifespan of these systems. This paper presents the initial experimental results of water quality improvements achieved at three different swales on the Sunshine Coast. Field testing undertaken on the three different swales verified the sediment removal performance was consistent with previous study results. This study also demonstrated that swales of short treatment lengths (up to about 10m) can reduce concentrations of total suspended solids (TSS) by up to 75%. The results of this study suggest that using short swales to pre-treat urban stormwater runoff before it enters permeable pavement systems could significantly reduce clogging of permeable pavement systems. This could significantly extend the effective life of permeable pavements as well as considerably reduce ongoing maintenance costs.