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Permeable Pavements. Shingle Creek Watershed Management Commission May 31, 2011. Outline. Purpose of presentation Types of pavements and applications Benefits Design considerations Maintenance considerations Example projects Questions. Types of Permeable Pavements. Porous Asphalt
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Permeable Pavements Shingle Creek Watershed Management Commission May 31, 2011
Outline • Purpose of presentation • Types of pavements and applications • Benefits • Design considerations • Maintenance considerations • Example projects • Questions
Types of Permeable Pavements • Porous Asphalt • Pervious Concrete • Pervious Pavers Permeable pavement has pores or openings that allow water to pass through the surface and stone base material and infiltrate into the underlying soils.
Porous Asphalt Pervious Pavers Pervious Concrete
John Barten, second from right, riding on pervious pavement in Medina around 1905.
Project Applications • Streets • Parking lots • Sidewalks and paths • Driveways • Patios • Playgrounds
Potential Benefits • Reduces the rate and quantity of stormwater runoff • Reduces stress on the sewer system • Recharges groundwater • Filters out silt, pollutants, and debris • Maintains natural drainage paths • Reduces standing water nuisance
Potential Benefits • Reduces stormwater infrastructure needs (pipes, ponds, catch basins) • Offers good alternative to conventional stormwater mitigation • Better erosion control • Reduces ice buildup and need for salting during the winter • Provides better traction
Design Considerations • Soils • Depth to groundwater • Traffic loading • Slopes • Blowing dust and debris
Design Considerations • Unique site features • Agency stormwater regulations • Frost penetration
Permeable Pavement Limitations Use of permeable pavement is not recommended in the following cases: • Industrial “brownfield sites or sites with contaminated soils • Where site layouts direct clogging sediment on the pavement surface • Sites with excessively steep grades
Maintenance Considerations • Protect pavement from silt and sediment during and after construction • Vacuum sweep at least twice a year • Do not seal coat • Do not sand • Use caution when snowplowing • Post signs advising maintenance crews
Maintenance Considerations • Perform periodic inspections; look for clogging, raveling, cracking, and wear • Other???
Paired Intersection Study, Robbinsdale, MN Porous asphalt test section - Abbott/41st , 2009
Cost • Test section = 150 feet long, 27 feet wide • Traditional pavement, contract unit prices = $14,125 =$32/SY • Porous pavement • Site 1 = $42,670 • Site 2 = $32,200 • “Upcost” = $35-50/SY
Residential Street Paving Project, Shoreview, MN Lake Owasso Asphalt replaced with pervious concrete, 2009
Water Infiltration Demohttp://www.youtube.com/watch?v=j_z0xRPbExY
Pervious Concrete Cost Comparison Common Excavation – 11,000CY($6.00/CY) = $ 66,000* Fabric – 11,000SY($1.00/SY) = $ 11,000 1-1/2” Crushed Rock – 5000CY($52.00/CY) = $260,000* 7” Pervious Concrete – 8470SY($46.50/SY) = $394,000 Total Cost for Pervious Concrete System = $731,000 Per SY Cost for Pervious Concrete System = $ 86.30** *Average depth beneath concrete = 1.75-feet Estimated Bituminous Road Cost = $257,000 Estimated Underground Infiltration Cost = $417,500 Total Est Cost – Bit Road & Infiltration = $674,000 Per SY Est Cost – Bit Road & Infiltration = $ 79.60** **8.5% Increased Cost for Pervious Concrete
Wolner Field Parking Lot, Mound, MN Before After Asphalt replaced with pervious concrete and draintile, 2007
Mound Transit Center, Mound, MN Installed pervious pavers, 2007
Little Six Casino, Prior Lake, MN Porous asphalt pavement in parking lot, 2009
Brainerd Area Porous asphalt parking lot, 2006