Spatial Analysis of the Water Harvesting Potential of Permeable Pavements in Australia

An increase in impermeable surface areas with urban development contributes to the rapid and large amount of surface runoff during rainfall. This often requires higher capacity stormwater collection systems, which can cause stress on the existing drainage system and this subsequently contributes to urban flooding. However, urban runoff can be reduced and managed for flood control and converted into a useful resource by harvesting and reusing the water. This can be achieved by switching from impermeable to permeable pavements. However, the amount of stormwater that can be harvested in a permeable pavement system depends on many factors, including rainfall, the water reuse demand and the materials used. This research aims to assess the requirements for permeable pavement design across Australia to balance demand, runoff reduction and construction requirements. A design approach employing the hydrological effects of the infiltration system was adopted for the analysis, along with a spatial analysis for a probabilistic prediction. A relationship was also established to predict a probable design thickness of pavement for various parameters. The research showed that in most Australian cities, for a 120 mm permeable pavement thickness, 40–80% of rainfall-runoff could be harvested, meeting about 10–15% of domestic water demand. The approach developed in this study can be useful for screening the potential of permeable pavements for water harvesting and for predicting spatially where a circular economic approach can be more efficient.