Porous asphalt material allow water runoff to pass through the porous material into a stone base, then into the soil below, recharging the groundwater supply.
There are several observed benefits from using this type of material that, with proper installation and maintenance, can allow for infiltration of up to 80% of annual runoff water volume.
For one, the porous material acts as a filter for the contaminants from the water runoff prior to its discharge, it reduces peak stormwater velocity as well as volume, which could alleviate some of the problems associated with downstream floodings.
Porous blacktop materials are, according to the Pennsylvania Department of Environmental Protection, usable in all types of sites, from residential to commercial and industrial sites.
Depending on the regional stormwater retention guidelines, porous material on the pavement may allow for land use in places that otherwise would potentially not meet the minimum requirements.
Due to the nature of the material installing porous blacktop may also require less curbing and storm sewers in the project area.
Finally, the porous material may also prove to provide improved traction in icy conditions than what you'd expect from traditional blacktop.
Some of the best places to learn about the usage of porous blacktop include:
- store.hotmix.org/index.php?productID=179 (Porous Asphalt Pavements for Stormwater Management booklet)
From Porous Asphalt page to Asphalt Guide index