Urban Runoff Mitigation by a Permeable Pavement System over Impermeable Soils

Abstract

The respective runoff from a 200 -m2 permeable pavement test site and an adjacent 850 -m2 conventional asphalt road catchment in Auckland, New Zealand, was monitored concurrently between 2006 and 2008. Despite installation over relatively impermeable subgrade soils, and on an atypically high slope (6.0–7.4%) and active roadway, the overall hydrologic performance of the permeable pavement was exceptional. Measured discharge from the permeable pavement underdrain demonstrated peak flow (81 storms) comparable to or below modeled predevelopment conditions for most storms, regardless of antecedent conditions, including a 10-year, 24-h annual recurrence interval event. For large events (5% exceedance), underdrain discharge volume was comparable to predevelopment conditions, but it was substantially less than asphalt runoff for all events up to approximately 70% exceedance. The distributions of peak flow and volume were statistically different between the asphalt catchment runoff and the permeable pavement under...