By Peter Lew, RA, MACS
Pervious concrete is a good “paving” choice for parking lots, especially during the summer months. The textured surface created by the aggregate produces less glare from standing water, better traction for vehicles (less potential for hydroplaning as it does not hold water), less ponding, and less spray. Pervious concrete also reduces heat island effects allowing the concrete to cool down after the sun goes down on hot summer nights.
Pervious paving is the combination of a design/material/installation technique that creates a paved surface which allows for the natural percolation of water (and air) down into the sub-soil. Pervious paving comes in a number of forms: permeable grass/gravel pavement systems, pervious concrete, porous asphalt, and porous brick or stone.
Structurally, pervious paving systems are made of concrete,
asphalt, stone, brick, grass, or gravel. The design, installation technique, and combination of materials are determined by the nature of the type of use they are needed for.
The US-EPA has listed “pervious paving” as a “best management practice” technique for land use development.
There are a number of compelling environmental & financial reasons to incorporate pervious paving into your site designs:
- Pervious paving is a valuable storm water management tool. Impervious pavement (i.e. traditional parking lots) collects vehicular fluids, solid waste, etc. and prevents them from washing into water sources. Pervious paving traps particles like these and allow microorganisms/bacteria that feed on hydrocarbons located within the material who will break them down.
- Pervious paving has potential LEED credits:
- Controls storm water runoff & prevents pollution (SS-6.1, SS-6.2)
- Reduces heat island effects (SS-7.1)
- Use of recycled content (MR-4)
- Use of local and regional materials (MR-5)
- Water use (WW-1.3)
- Innovation and design (ID-1)
- Pervious paving systems help protect landscaping by allowing air and water to filter into the plant root systems while still providing usable paved areas.
- EPA storm water regulations require the reduction of overall run-off and a reduction in pollution levels. Pervious paving helps achieve both those goals by lowering peak water flow thru drains and minimizing flooding while increasing the aquifer recharge.
- Pervious paving areas reduce the need for large detention ponds required for storm water thereby increasing the area available for development. Reduced storm water piping/structures.
- Irrigation system needs can be reduced because there will be more ground water available
- Reduced runoff decreases containment system costs
- Decreased storm water input fees
- Potential lower life cycle costs & more local materials cost