What is the difference between impervious and permeable surfaces?
Impervious surfaces in landscape, are solid areas such as; driveways, patios, and walkways, which do not allow water to penetrate. The more impervious surfaces on a site, the more run-off there is. The consequence of run-off is an increased speed of water flow, which cannot be absorbed into the ground as readily, which increases erosion and dumps an excessive amount of pollutants into storm drains, streams or oceans.
The preference would be a permeable or porous surface – an area designed to allow water to slow down and penetrate or settle into the ground. Permeable surfaces aid in the reduction of pollutants and reduce erosion. We suggest using natural stone wherever possible, along with permeable joints and open areas with soft-scape, to assist in overall water run-off management. Monarch Stone International offers a wide variety of natural stone and cobblestone options for this purpose.
The American Society of Landscape Architects has more information on this critical issue and referrals to a professional landscape architect in your area.