Restoration of Infiltration Capacity of Permeable Pavers

Abstract

The restoration of the infiltration capacity of permeable pavers is covered and the hypothesis that permeable paver infiltration capacities decrease with age and increased traffic use is tested. The possibility of street-weeping/vacuuming the surface to maintain infiltration capacities of permeable pavers is also investigated. Permeable pavers allow water to easily infiltrate into the subsurface layers, thus reducing the volume of runoff reaching receiving waters. As permeable paver installations age and are heavily used, the infiltration capacity decreases due to clogging of the external drainage cell (EDC) with fines (silt and clay), organic matter and extractable solvents from automobiles (primarily oil and grease). An eight-year old installation of two permeable pavements in a parking lot at the University of Guelph was studied. Infiltration rates were tested before and after material was extracted from the EDC's and a particle size and constituent analysis was done on the soil. The extracted material was tested for a number of different organic and chemical constituents such as heavy metals, nutrients and organic matter. Preliminary results of the study indicate that the infiltration capacity decreases with increasing average daily traffic counts, and as the amount of organic matter and fine matter within the EDC material increases. Furthermore, the tests indicate that the infiltration capacity can be significantly improved by removing 10–20 mm (0.394–0.788 inches) of EDC material, a removal depth that can be achieved by using modern street sweeping equipment.