Porous Pavement

Porous Pavement systems are excavated areas filled with gravel and paved over with a porous concrete or asphalt mix. Porous pavements are implemented in places where the surface has to provide a firm support for vehicle traffic, such as streets and parking lots.

Normally, all rainfall will immediately pass through the pavement into the gravel storage layer below where it can infiltrate at natural rates into the native soil.

The figure below shows a porous pavement structure, which has the following components:

• Surface
• Pavement material
• Soil (optional)
• Storage
• Drain (optional)

 

Figure: Porous Pavement structure layers

Essentially, the hydraulic functionality of porous pavements is similar to that of the bioretention cells, except that the soil layer (and vegetation) is replaced by some porous asphalt or concrete.

Some types of porous pavements may be subject to clogging by fine sediment particles, which reduces their infiltration capacity.