What is it?
Pervious pavement is a hardscape surface that allows water to pass directly through the surface and infiltrate into the ground. Pervious pavement materials can include poured asphalt, concrete, and interlocking concrete pavers installed over a supporting base of crushed stone that helps to store and infiltrate stormwater. Pervious pavements can offer a simple means of integrating green infrastructure if your development footprint is tightly constrained. The key difference between conventional and pervious surfaces is:
- Poured pavements – the smallest stones are left out of the mixture during manufacturing, allowing water to infiltrate through the vacant spaces.
- Interlocking pavers – the joints are filled with sandy material that also allows water to infiltrate.
When is it used?
Pervious pavement can be used effectively in hardscape areas designed for foot and bicycle traffic (such as sidewalks and greenways) as well as alleys, parking stalls, and basketball courts. It should not be used for areas of heavy car or truck traffic, or where nearby industrial, agricultural, or landscape operations may lead to heavy sediment or organic material accumulation that could clog the system.
What are some key considerations?
- Construction should not take place during rain or snow, when the subsoil is frozen, or when there is significant accumulation of sediment or debris. These conditions can permanently clog the pervious pavement.
- Snow and ice, especially from areas treated with sand, should not be stockpiled on a pervious pavement system.
Myth: Pervious pavement doesn’t work in cold weather climate.
Fact: Pervious pavement is not negatively affected by freezing; this pavement remains porous and does not become clogged from frozen runoff. Furthermore, pervious paving requires less deicing throughout the winter season, and is more resistant to frost heave than standard pavement, thus reducing maintenance costs and salt use.