Stormwater treatment using permeable pavements

Permeable pavements are generally used in water-sensitive urban design as a component of a treatment train and as a source control measure for reducing stormwater flows and pollutant loads. In Australia, permeable pavement systems are an emerging technology and consequently there are few installations more than 10 years old. The performance of permeable pavements in terms of treatment of urban stormwater runoff from a number of typical, but different urban catchments is discussed. Water quality monitoring was carried out in the field to quantify the improvement that permeable pavement systems can make to runoff quality at a car park located at North Haven in Adelaide, South Australia, that utilise both conventional and permeable pavement systems. Extensive laboratory analysis using stormwater collected from four sites was carried out to assess the effectiveness of permeable pavement systems for reducing pollutant discharges. In general, the permeable pavement systems were found to improve stormwater quality when tested at a 5% significance level. The results show that, on average, permeable pavements were able to reduce nutrient concentrations (total nitrogen and total phosphorus), heavy metals (zinc, lead, copper, cadmium and nickel) and total suspended solids. The reductions in pollutant concentrations can be mainly attributed to mechanical filtration by various components of the permeable pavement system.