Description   Mechanisms   Applications   Specifications   Plans   Water Quality   Maintenance   Resources   Back

US Environmental Protection Agency, 2005.

Description

Pavement constructed from materials that allow the infiltration of water. A permeable surface formed to allow water penetration reduces runoff and increases filtration. Additional surface area is not required.

Mechanisms

Reduces runoff by allowing precipitation to infiltrate through porous pavement instead of running off into drainage ditches and storm sewers. The porous material offers minimal filtration of the water, but designs that use vegetation result in more substantial treatment. Subsurface soil under the porous pavement may also trap and treat pollutants depending on its characteristics and the depth to groundwater.

US Environmental Protection Agency, 2002.

Applications

• Reduces runoff contamination from parking lots, light traffic roadways, and other impervious surfaces.
• Well suited for infrequent event parking.
• Not for use in high traffic areas or heavy vehicles.
• Not recommended for steep slopes.
• Regular maintenance required to maintain porosity.
• Not for use with impermeable soils, underlying soil critical for site selection to avoid pounding and runoff.
• Not for use in highly polluted runoff areas, no dilution results from isolated high concentration releases.
• Not for use in areas with high wind erosion buildup.
• Limited use in locations requiring snow removal and those that use salt and sand deicing procedures.

Detailed Specifications

Design Values*:
• Drainage time through entire system 12-72 hours.
• Soil permeability 0.5-3 inches per hour.
• Volume 6-month 24-hour rainstorm event.
• Slopes less than 5%.
• Minimum depth of 4 feet to bedrock or high water table.
• Minimum of 100 feet from well water supplies.
• Pavement surface area less than 15 acres.
• Minimum setback from buildings or structures:
• 10 feet down gradient.
• 100 feet up gradient.
• Filter aggregate of 1.5-3 inch diameter stone.
• Depth of filter aggregate is variable, dependent upon porous pavement type.
• Install filter fabric.
• For more information visit:
  US EPA Porous Pavement Storm Water Technology Fact Sheet,
  US EPA Porous Pavement Post-Construction Storm Water Management in New Development & Redevelopment.

*Note: Local governments may use different design values than those listed above, be sure to comply with any applicable laws and regulations.

Plans

Modified from MWCOG, 1987 (Cited in United States Environmental Protection Agency. Storm Water Technology Fact Sheet Porous Pavement, 1999).

Water Quality

• 82-95% sediment removal.
• 65% total phosphorus removal.
• 80-85% total nitrogen removal.
• 98-99% metal removal.
• High removal rates for zinc, lead, and chemical oxygen demand.

(The capacity to remove some pollutants will become exhausted with time.)

• For more information visit:
  US EPA Porous Pavement Storm Water Technology Fact Sheet,
  US EPA Porous Pavement Post-Construction Storm Water Management in New Development & Redevelopment.

Maintenance

• Vacuum sweeping to maintain porosity multiple times per year.
• High pressure hosing after each vacuum sweeping.
• Remove large debris and sediment buildups monthly.
• Repair damaged section annually.
• Annual inspection after a rainfall for clogging.
• Mow and seed adjacent bare areas as needed.

Resources

The Michigan Department of Transportation. April 1998. Highway Stormwater Runoff Study. pp. 30-31.

Metropolitan Washington Council of Governments. 1987. Controlling Urban Runoff: A Practical Manual for Planning and Designing Urban BMPs.

United States Environmental Protection Agency. August 15, 2002. Porous Pavement. Post-Construction Storm Water Management in New Development & Redevelopment.
http://cfpub.epa.gov/npdes/stormwater/menuofbmps/index.cfm (January 2006).

United States Environmental Protection Agency. June 30, 2005. EPA Headquarters Low Impact Development Program.
http://www.epa.gov/greeningepa/stormwater/hq_lid.htm (February 2006).

United States Environmental Protection Agency. September 1999. Porous Pavement. Storm Water Technology Fact Sheet. EPA 832-F-99-023.
http://www.epa.gov/npdes/pubs/porouspa.pdf (January 2006).

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