Using Permeable Eco-paving to Achieve Improved Water Quality for Urban Pavements

This paper describes the planning, design and construction of a permeable pavement as a practical demonstration of the benefits of eco-paving in Australian environmental management. The paper addresses the use of permeable pavements as part of a Water Sensitive Urban Design that allows infiltration of stormwater, reduction of pollutants and slow reticulation of the stormwater to an ecologically sensitive water system. Management of the quantity and quality of urban stormwater run-off is a major concern for government authorities. The increase in impervious surfaces associated with urbanisation of catchments results in an increase in the volumes of stormwater runoff that must be handled by the stormwater drainage systems and a consequent increase in the ability of the stormwater runoff to transport pollutants from the catchment surface to the downstream receiving waters. These pollutants include those from vehicle exhausts, brakes and tyres, community activities, and atmospheric deposition. Where the stormwater system drains to ecologically sensitive zones, such as beaches, lakes or creeks, communities demand that the quality of the stormwater discharged into these water bodies must not lead to their degradation. This paper describes how, in a seaside suburb of Sydney, Australia, Manly Council assisted by the Urban Stormwater Initiative of the Commonwealth Department of Environment and Heritage, Environment Australia, has replaced an old impervious asphalt roadway with a Uni-Ecoloc concrete segmental permeable pavement system as part of a stormwater project using the concepts of Water Sensitive Urban Design. Issues covered include the structural design of the pavement to carry traffic and the hydraulic design of the pavement to allow the capture of the storm events, control of water quality at the source, reduction of the volume of storm water reaching drainage system, permeable pavers to ensure traffic flow/frequency is satisfied. Factors influencing the choice of paver and pavement materials are discussed and the construction procedures are described including in-situ assessments of basecourse permeability. The project is now in service and is being monitored on a long-term basis. However, the paper presents preliminary assessments of the impacts and utility of the project.