Hydrologic Comparison of Four Types of Permeable Pavement and Standard Asphalt in Eastern North Carolina

TLDR

A permeable pavement parking lot in eastern North Carolina was monitored from June 2006 to July 2007, comparing four permeable pavement types (pervious concrete, two permeable interlocking concrete pavements with 12.9 % and 8.5 % open surface area, and concrete grid pavers filled with sand) to standard asphalt; the site had poorly drained soils, a crushed stone base, and a perforated underdrain, and performance differences were linked to base storage volume and sand‑filled media. All permeable pavements markedly reduced surface runoff volumes and peak flow rates versus asphalt (p < 0.01); among them, CGP yielded the highest runoff, but PICP1 and CGP had the lowest total outflow, lowest peak flows, and longest time to peak, indicating that permeable pavements performed similarly yet were substantially different from asphalt.

Abstract

A permeable pavement parking lot in eastern North Carolina consisting of four types of permeable pavement and standard asphalt was monitored from June 2006 to July 2007 for hydrologic differences in pavement surface runoff volumes, total outflow volumes, peak flow rates, and time to peak. The four permeable sections were pervious concrete (PC), two types of permeable interlocking concrete pavement (PICP) with small-sized aggregate in the joints and having 12.9% (PICP1) and 8.5% (PICP2) open surface area, and concrete grid pavers (CGP) filled with sand. The site was located in poorly drained soils, and all permeable sections were underlain by a crushed stone base layer with a perforated underdrain. All permeable pavements significantly reduced surface runoff volumes and peak flow rates from those of asphalt (p<0.01). Of the permeable pavements, CGP generated the greatest surface runoff volumes (p<0.01). The PICP1 and CGP cells generated significantly lower total outflow volumes than all other sections evaluated (p<0.01), and had the lowest peak flows and the longest time to peak. The response of the PICP1 cell was likely due to an increased base storage volume resulting from an elevated pipe underdrain whereas the CGP cell response was attributed to water retention in the sand fill layer. Overall, different permeable pavement sections performed similarly, but were substantially different from asphalt. Subtle differences in the performance of CGP were primarily due to the characteristics of the sand filled media compared to small aggregate typically used in PC and PICP joints and bedding.