Evaluation of Various Types of Permeable Pavements with Respect to Water Quality Improvement and Flood Control

In many U.S. states, different permeable pavement types are considered to have the same capabilities in reducing runoff, and they are not credited with improving water quality. To test various permeable pavement designs, a parking lot consisting of four different types of permeable pavements and standard asphalt was constructed in Kinston, NC. The permeable pavement sections consist of pervious concrete (PC), permeable interlocking concrete pavers (PICP) with 8.5 % void space, PICP with 12.9 % void space, and concrete grid pavers (CGP), each covering a 1200 sq. ft. area with a 10 in. gravel storage layer. The purpose of this study is to evaluate and compare the effects of each pavement type on water quality and runoff reduction. Site analyses on every rainfall event began in March, 2006, and will continue through March, 2007. Preliminary results indicate significant (p<0.05) peak flow and volume reductions from all permeable pavements. Additionally, there has been little to no runoff observed from any of the pervious sections. Pollutant removal performance by the pavements has widely varied. As a result of this study, it is expected that the state of North Carolina will make a judgment on how much pollutant removal credit permeable pavement types should receive. Also, this study may be used to determine whether or not stormwater credit should vary based on pavement type.