Q: What are the environmental benefits of permeable pavement?
Paul S., Indianapolis
A: One of the biggest benefits of permeable pavement systems — which work like a sponge to soak water through pavement and into the ground — is their ability to prevent chemicals and debris from entering storm drains and eventually, lakes, rivers and oceans.
Rain instead percolates through stone- or soil-filled joints between pavers or through pores in expanses of pavement and into an underground gravel base that filters gasoline, car oil and other contaminants from the water.
Because more precipitation soaks into the ground, rather than running down the nearest storm drain, permeable pavement reduces flash flooding and erosion. It also helps replenish the water table and limit how much water is needed for landscaping.
In addition, permeable systems reduce the need for subsurface drains, piping and sewers that local governments build to accommodate runoff.
Permeable pavement works for just about any hardscape project, including walkways, patios and driveways. These systems function ideally in areas that flood frequently or provide poor drainage. Permeable pavement is popular in the Pacific Northwest, in rainy cities such as Seattle and Portland, Ore.
There are two main types of permeable paving:
• Pavers, which come in all shapes, sizes and designs, from small bricks to large stones.
• Porous pavement, which looks similar to cottage cheese and can be made from concrete or asphalt.
If properly constructed, permeable pavement can last for 20 or more years. These systems require little maintenance, often only periodic removal of debris from joints or holes with a small wet-dry vacuum.
Permeable systems can cost two to four times more than a regular paving project, but may also save you the cost of an erosion solution. Pavers can range from $12 to $16 each, installed. A permeable driveway can cost $5,000 or more. Some local governments offer tax breaks to property owners who install these pavement systems.
Because a permeable system requires proper installation and moving lots of dirt, it may be best to hire a professional. The Interlocking Concrete Pavement Institute offers certification for permeable pavement service providers.