Photo 2:

An example of porous concrete.

Permeable pavements allow stormwater runoff to filter through surface voids into an underlying stone reservoir where it is temporarily stored and/or infiltrated. The most commonly used permeable pavement surfaces are pervious concrete, porous asphalt and permeable interlocking pavers. Permeable pavements have been used for commercial and residential sites to replace traditionally impervious surfaces. These include roads, parking lots, driveways, sidewalks, plazas and patios. While the designs vary, all permeable pavements have a similar structure, consisting of a surface pavement layer, an underlying stone aggregate reservoir layer, optional underdrains and geotextile over uncompacted soil subgrade. Figure X.1 illustrates the three most commonly used systems; pervious concrete, porous asphalt and permeable interlocking concrete pavement.

The reservoir thickness is determined by structural and hydrologic design analyses. From a hydrologic perspective, permeable pavement is typically designed to manage rainfall landing on the pavement surface area. It may accept runoff contributed by adjacent impervious areas such as driving lanes or rooftops. However, sediment control from adjacent impervious or vegetated contributing areas is required to avoid clogging of the permeable pavement surface.

The individual articles comprising this section on permeable pavement may be viewed as a single article.


Photo 3:

An example of permeable interlocking pavement