Pervious pavement systems provide stormwater management. Water drains through the pavement to a cleansing layer of gravel. The gravel or stone acts as a natural filter, clearing the water of pollutants. The EPA Storm Water Phase II regulations provide programs and practices to help control the number of contaminants in our waterways. Traditional concrete and asphalt hardscapes collect oil, anti-freeze, and other automobile fluids that can be washed into streams, lakes, and oceans when it rains.
These contaminants are trapped within the permeable system and at the location of any geotextile fabric separating the pavement from the subbase or subgrade support. Hydrocarbons, such as oils, are a food source for many naturally occurring bacteria and fungi. The microorganisms feed on the oil and biodegrade it into simpler chemical components that are released into the atmosphere. Close to 99 percent of oils introduced into pervious pavements are trapped and biodegraded.
Permeable paving prevents flooding by keeping the rainwater on the property instead of rushing into our street. When it rains, permeable paving allows stormwater to seep into the void spaces in the subsurfaces where water can flow slowly or be reused on the property.