Powdermill Nature Reserve

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Water-permeable Parking Lot 


Parking lots can be huge environmental hazards. Water from rain and snow can mix with gasoline, floatable debris, and other harmful liquids that lie on parking areas. This contaminated water drains into streams, causing erosion problems and harming aquatic life. Storm water runoff not only affects the stream it runs into, it has an effect on the entire watershed. This problem was avoided at Powdermill with the installation of a water permeable parking lot and driveway. Rather than running off of the parking lot and into the stream, water flows down into the ground and recharges the groundwater.

The method used to construct the green parking area was simple. Trained loggers from the Sustainable Forestry Initiative of Pennsylvania cleared the designated land area by cutting down marked trees and removing the stumps. The ground was then leveled and a geotextile separation layer was installed to help keep the natural ground in place. Layers of topsoil, gravel, and sand were placed on top of the separation layer for support. Next, Geoblock Porous Pavement units were arranged in rows to cover the entire parking lot. These plastic units make the parking lot permeable by allowing water to pass through them and infiltrate the natural ground. A mixture of sand and topsoil were added on top of the units and grass seed was planted. The result is a parking lot that is both aesthetically pleasing and environmentally friendly.

The Finished Product