Managing Stormwater Runoff The Power of Permeable Pavement

Managing Stormwater Runoff: The Power of Permeable Pavement

Among the various negative impacts of land development is stormwater runoff due to impervious paved surfaces. This runoff can lead to a host of problems including water pollution, flooding, stream bank erosion, decreased recharge of groundwater, and ponding on roadways.

One highly effective solution for managing runoff is permeable pavement. These systems allow stormwater to percolate through to an aggregate sublayer where it can infiltrate into the subsoil or discharge via an underdrain. Commonly used permeable pavements include porous asphalt, pervious concrete, and permeable interlocking concrete pavers (PICP). Porous asphalt and pervious concrete are similar to standard asphalt and concrete but with fine aggregates omitted from the mixture; PICP blocks are usually made from solid concrete. Starting from the bottom, a typical system consists of an uncompacted subgrade, a filter fabric that prevents migration of fine particles from the subgrade, a storage bed of clean, uniformly graded crushed stone, a ground-stabilizing choker course, and a porous surface layer.

Permeable pavement reduces stormwater runoff by allowing water to slowly release into the ground over a large area while filtering out pollutants and recharging groundwater. Roadways benefit from improved wet-weather traction and visibility, reduced noise, and reduced surface ponding. By cooling stormwater gradually, permeable pavement helps mitigate urban heat island effects and reduces temperature impacts on local waters. Because permeable pavement retains heat, it resists frost, promotes the melting of snow and ice, and reduces the need for deicing. Finally, the need for stormwater management systems like detention basins and retention ponds is reduced, which is particularly cost-effective in areas where land values are high.

There are a number of disadvantages, design limitations, and maintenance considerations that must be factored in when considering permeable pavement. Due to the potential for groundwater contamination, it should not be used in areas with high pollutant concentrations or where sediment loading is anticipated. Costs are estimated at about one-third higher than conventional impermeable systems, but this is largely offset by a reduced need for stormwater management infrastructure and winter maintenance.

Finelli Consulting Engineers, a Division of UTRS, can assist clients with all their permeable pavement design needs. For more information, contact us at 908-835-9500 or FCE@finellicon.com. New Jersey Stormwater Best Management Practices for Pervious Paving Systems can be found here.