Permeable Pavements

Shingle Creek Watershed Management CommissionMay 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.

Pervious Pavers

Porous Asphalt

Pervious Concrete

Pervious Pavement Hydrology

Porous HMA (or Dense HMA with Piping)

John Barten, second from right, riding on pervious pavement in Medina around 1905.

Water Storage in Pervious Concrete System

Porous Asphalt Section

Pervious Concrete Paver

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???

Ongoing Maintenance -Vacuum Sweeping

Sweepings

Maintenance Warning Signs

Paired Intersection Study, Robbinsdale, MN

Porous asphalt test section - Abbott/41st , 2009

Porous Subgrade Preparation

Porous Asphalt Placement

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

Shoreview Water Infiltration Demo

Pervious Concrete Cost ComparisonCommon Excavation – 11,000CY($6.00/CY) = $

66,000*Fabric – 11,000SY($1.00/SY) = $ 11,0001-1/2” Crushed Rock – 5000CY($52.00/CY) = $260,000*7” Pervious Concrete – 8470SY($46.50/SY) =

$394,000Total Cost for Pervious Concrete System =

$731,000Per SY Cost for Pervious Concrete System = $

86.30** *Average depth beneath concrete = 1.75-feet

Estimated Bituminous Road Cost = $257,000Estimated Underground Infiltration Cost = $417,500Total Est Cost – Bit Road & Infiltration = $674,000Per 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

Pavement Cost Comparison

Mound Transit Center, Mound, MN

Installed pervious pavers, 2007

Subgrade preparation

Little Six Casino, Prior Lake, MN

Porous asphalt pavement in parking lot, 2009

Brainerd Area

Porous asphalt parking lot, 2006

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• You've done it a thousand times.

• It comes naturally to you.

• You know what you're doing, its what you've been trained to do your whole life.

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