The benefits of porous paving are numerous. An article by Environmental Building News concisely reviews the basics – in particular the use of natural stone pavers installed with permeable joints.

Porous paving (also referred to as permeable or pervious) allows rainwater to infiltrate into the ground. Some porous pavement types are engineered to allow infiltration while also withstanding regular vehicle use. 

Several types are listed by EBN including:

  • Porous concrete
  • Porous asphalt
  • Plastic geocell unit pavers
  • Loose aggregate 
  • Unit Pavers (concrete, brick, STONE)

Of the mentioned categories, unit pavers – natural stone pavers, can be installed with joints filled with uniform aggregate to allow drainage. Monarch Stone International supplies natural stone pavers, both reclaimed/salvaged antique Historic European Cobblestone®  and new-quarried stone, both of which are the most attractive and durable of paving material. The project in the photo is antique granite cobblestone (4″ wide x 7″ long) set on a permeable base with porous joints.

Porous pavement depends on a subsurface that can absorb water. This system of multiple layers, which is usually deeper and more carefully engineered than the average roadbed, supports loading and provides reservoir capacity for stormwater. By stopping stormwater from pooling and flowing away, porous paving can help recharge underlying aquifers and reduces peak flows and flooding. That means that streams flow more consistently and at cooler temperatures, contributing to healthy ecosystems. Stormwater pollutants are broken down in the soil instead of being carried to surface waters.

Porous paving also contributes to healthy trees along streets and in parking lots. Those trees, along with turf planted in unit pavers, reduce the urban heat island effect. Porous paving is quieter than conventional paving and safer for drivers and pedestrians because less water pools on its surface. It can cost more than conventional paving on a unit basis, but projects can realize big cost savings and permitting benefits by reducing stormwater infrastructure such as retention ponds.

We firmly agree with Environmental Building News that working with experienced designers and contractors is key, along with proper maintenance is also essential to keeping porous pavement functioning.