Permeable Pavement 101

Permeable pavement is one of the most popular best management practices (BMPs) in the Colonial SWCD service area with landowners who are considering applying for the Virginia Conservation Assistance Program (VCAP). Although it is generally one of the more expensive practices to install, if a landowner is eligible for VCAP they could receive up to $20,000 to offset the expense, depending on the size of their project area.

Permeable pavement is a BMP designed to capture stormwater runoff as it falls or flows onto the practice surface. There are several different types of permeable pavement, but interlocking grid pavers are the most common for residential uses. These systems look like a traditional brick paver system from the surface, but when they are installed there’s actually up to one foot of gravel underneath the pavers, which serves as a reservoir for captured stormwater. By capturing this water and preventing continued flow across the surface, the practice helps to prevent erosion and flooding. In between each paver is a small void, generally filled with very small stones, and runoff flowing or falling onto the surface infiltrates into the reservoir through those spaces. The diagram below shows a typical permeable pavement cross section, including the stone reservoir and infiltration spaces between the pavers.

Diagram showing how permeable pavement is constructed, with several layers of gravel that is placed beneath the permeable pavers themselves. — Photograph courtesy of the City of Santa Barbara Sustainability and Resilience

Permeable pavement is most often used to replace existing impervious driveways, walkways, and patios, although in the appropriate conditions permeable pavement can be installed in vegetated areas to capture runoff from a downspout or adjacent impervious surface. To learn more about permeable pavement or to determine if your property is eligible for a permeable pavement VCAP application, please feel free to reach out to me or my colleague Emma Rich.