Permeable Pavements

Permeable pavement structures allow rainwater to infiltrate through the pavement surface as well as underlying layers to ultimately reach the subgrade soil. If the subgrade has adequate permeability, then the water can further infiltrate into the soil and reach the ground water. Otherwise, a drainage system may be installed to divert the water accumulated in the structure to a different location.

Traditional pavement structures are designed to prevent water from entering the pavement and drain any water from inside the structure to the sides and away from the structure and the subgrade soil. In a structure designed to be impermeable, any accumulation of water will lead to premature failure. Therefore, permeable surfaces must be supported by permeable structures which are specifically designed to function when water infiltrates the structure. Permeable structures will normally be thicker to give water a place to be stored and will use materials with good drainage properties and less sensitive to changes in moisture. To ensure infiltration of water into the subgrade, it is not uncommon to leave the subgrade soil uncompacted and instead use a very thick base/subbase section to provide structural support for the surface layer.

Why use this stragegy?

In general, benefits of permeable pavements include recharge of the ground water reserves; less consumed energy and natural resources; low-impact infrastructure and cost-effective method for stormwater mitigation by eliminating the use of drainage structures.

How to use it?

Consider using pervious concrete or porous asphalt on a specially designed permeable pavement structure. Permeable structures are best suited for parking lots or low traffic roads.

Where to learn more and who to contact?

Environmental Protection Agency cool pavement compendium which includes information on permeable pavement:

American Society of Civil Engineers Permeable Pavements Manual:

National Ready Mix Concrete Association:

  • Pervious Pavement web site includes design guidelines

National Asphalt Pavement Association:

  • Porous Asphalt web page includes links to design guidelines