Water Quality and Hydraulic Properties of the Permeable Friction Course

The objective of this study is to document the water quality benefits and the hydraulic properties of PFC. Stormwater runoff from a four-lane divided highway in Austin, Texas, USA was monitored at the edge of pavement at two sites before and after the installation of a PFC. Observed concentrations of total suspended solids and pollutants associated with particulate material were much lower in the runoff from the PFC than that derived from the conventional asphalt surface. Significant concentration reductions were observed for total suspended solids, total lead, total copper, and total zinc. The reduction in TSS concentration is about 90 percent and the average discharge concentration is less than 10 mg/L. Concentrations of dissolved constituents were not significantly different at either site. These results are generally consistent with findings of research conducted in Europe. Results of this study indicate that PFC performs as well as many types of structural controls for reducing the pollutants in highway runoff. Consequently, this material that has historically been used primarily for safety benefits should also be considered where reduction in pollutant discharge is desired. This material incorporates runoff treatment within the pavement itself, which facilitates its use in retrofit situations where additional right-of-way may not be available for stormwater treatment.