Retrofitting impervious pavement with materials designed to infiltrate stormwater is a viable green infrastructure solution for stormwater management. The use of permeable pavers in parking lots and driveways is well established as an effective way to reduce runoff and provide stormwater detention and pollutant control benefits. Some municipalities now recognize that municipal roadways can be designed to handle vehicular traffic and also function as a stormwater control measure. Greater acceptance of permeable pavers for roadway applications by design professionals is due in part to research completed by the University of California Pavement Research Center in 2014. This research validated design assumptions based on accelerated load testing to determine the effective shear capacity of each layer within the open graded aggregate pavement system in various saturated conditions.
Parts of Atlanta Georgia have struggled with flooding problems in recent years due to stormwater runoff from highly impervious areas of downtown Atlanta into downstream neighborhoods. Heavy rains have sent runoff and raw sewage from combined sewer overflows into homes and backyards forcing the city to address these reoccurring flooding events. In 2016, Atlanta retrofitted over four miles of roadways with permeable pavers to reduce flooding and flow to the antiquated combined sewer system. The aggregate reservoirs beneath the road surface provide over four million gallons of water storage capacity. Southeast Atlanta is currently home to the largest permeable interlocking concrete pavement retrofit project in North America. This presentation will review how Atlanta converted impervious roadways to PICP and the lessons learned related to utilities, roadway slopes, inspection, and maintenance.