PLASTIC GRID
INSIDE THE FLOODPLAIN | OUTSIDE THE FLOODPLAIN

What Is It?

Cost: $1.50-$5.75 per sq ft
Applications: Low speed vehicular traffic (e.g. parking lots, driveways, alleys, access roads), trails, pathways, bike paths. Can be used in retrofits or new construction.
Service Life: 10-20+ years

Plastic grids are an alternative pavement, consisting of a durable interlocking plastic grid filled with gravel or earth, or seeded with grass. The grid is very porous, allowing for high rates of infiltration (up to 3 ft/hr), and the modular plastic cells can reduce erosion and wear on gravel and grass pathways. Due to the flexibility of the grid components, plastic grids can be used on sites with uneven terrain, though maximum slope ranges from 6-12% due to traction limitations.

Regular maintenance is typically low. Vegetated grids will need to be mowed and may need irrigation and occasional reseeding, while non-vegetated grids may need to be refilled with gravel or crushed rock. Vacuuming may be necessary to maintain high permeability. Plastic grids can be easily added onto existing paving, though care should be taken to ensure that high volumes of runoff are not directly routed from adjacent impervious areas onto the grid, as sediment can quickly clog the void spaces. Plastic grids are often made from recycled materials. Load bearing capacities range from 24,000 lb/sq ft. to 823,680 lbs/sq ft.

Benefits

  • Enhances groundwater infiltration while reducing stormwater runoff volume, rate, and pollutants. Additional drainage facilities are not required.
  • Vegetated grids can lower urban air temperatures when moist due to evaporative cooling.
  • Quick installation time.
  • Reduces occurrence of black ice/freezing puddles in cold climates; requires fewer applied deicers.
  • Stabilizes grass/aggregate for driving and heavy foot traffic.
  • Grass contributes to carbon sequestration.

Drawbacks

  • Pollutants and deicing salts can infiltrate groundwater. Should not be installed in areas where hazardous material spills are possible.
  • Poorly placed grids can become clogged due to excess runoff from impervious areas.
  • Load bearing strength and durability generally lower than permeable pavers/asphalt/concrete. Aggregate is unstable.
  • Snow removal is difficult.
  • Unusable at high speeds.
  • Vegetated pavers require regular maintenance and may require additional irrigation during daytime.
  • Grass is easily damaged by pollution/heavy use.

Regulatory Impacts and Requirements

A summary of potential regulatory touchpoints follows below:
Plastic-Grid

Financing Options, Incentives, And Rebates

Additional Resources

PROJECT EXAMPLES

SAMPLE OF SUPPLIERS

SOURCES

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