Field survey of permeable pavement surface infiltration rates

The surface infiltration rates of 40 permeable pavement sites were tested in North Carolina, Maryland, Virginia, and Delaware. Two surface infiltration tests (pre- and postmaintenance) were performed on 15 concrete grid paver lots filled with sand. Maintenance was simulated by removing the top layer of residual material (13 - 19 mm). Simulated maintenance significantly (P < 0.007) improved the surface infiltration rate. The median site surface infiltration rate increased from 4.9 cm/h for existing conditions to 8.6 cm/h after simulated maintenance. Fourteen permeable interlocking concrete pavers (PICP) and eleven porous concrete (PC) sites were also tested. PICP and PC sites built in close proximity to disturbed soil areas had surface infiltration rates significantly (p < 0.0014 and p < 0.0074, respectively) less than stable landscape sites. Median PICP surface infiltration rates of each condition were 80 cm/h and 2,000 cm/h, respectively. Median PC surface infiltration rates with and without fines were 13 cm/h and 4,000 cm/h, respectively. This study showed that: (1) the location of permeable pavements; and (2) maintenance of permeable pavements were critical to maintaining high surface infiltration rates.