Protecting groundwater with oil-retaining pervious pavements: historical perspectives, limitations and recent developments

Pervious pavements are important systems used for source control in Sustainable Drainage Systems (SuDS), which allow water to infiltrate into hard surfaces and then slowly release it either to a drainage outlet or into the ground. They also remove low levels of pollution from the water by filtration and also by biodegradation of hydrocarbons, which are adsorbed to materials within the construction. Following a historical overview of research in this area, this paper describes an experiment that demonstrates the importance of the choice of geotextile in the retention of day-to-day emissions of oil from parked vehicles and the development and initial trials of an oil interceptor system, which has been incorporated within pervious surface construction. The results indicated that in the early years of the life of a pervious pavement the choice of geotextile has a vitally important impact on its oil-retaining role but that, after several years of silting, the choice may become less important. The results also demonstrated that modified direct infiltration pervious pavement systems, constructed on site from traditional materials and geomembrane, can effectively contain very large hydrocarbon spills.