Experimental Stormwater Parking Lot
In October 2009, EPA finished upgrading a major parking lot at its Region 2 laboratory in Edison, New Jersey, with low impact development (LID) features including three types of permeable surfaces. EPA plans to use this effort as a demonstration project to study the effects of the paving materials on stormwater runoff.
The Region 2 laboratory needed a 110-vehicle-capacity parking lot to provide safe and secure parking. The project began as a building and facilities improvement project under the Office of Administration and Resources Management (OARM). EPA’s Office of Research and Development (ORD) recognized the project as an opportunity for research and contributed funding that helped to install research instrumentation to evaluate the potential of permeable surfaces to lessen the effects of peak stormwater runoff on receiving streams, including stream bank erosion and negative effects on aquatic plant and animal life. ORD is evaluating permeable surfaces as part of a long-term research project examining multiple stormwater management practices.
The parking lot has two main goals:
- Reduce stormwater runoff by reducing impervious surfaces.
- Use the site to study the effects of three different types of permeable surfaces.
The overall objective of the project is to demonstrate and document the performance and capabilities of three permeable pavement systems—porous asphalt, porous concrete, and interlocking concrete paver blocks—at the same site. The parking lot will be monitored for hydrologic performance (the ability to accept, store, and infiltrate stormwater), water quality performance, urban heat island mitigation, maintenance effects, and parking behavior.
Design and Construction
The project removed existing concrete from the nearly 300,000-square-foot parking area and graded the surface, reusing the crushed concrete as a sub-base material. The project installed three types of permeable pavement surfaces in the parking lot, including 28 parking spaces made of interlocking concrete paver blocks, 41 parking spaces made of porous concrete, and 28 parking spaces of porous asphalt. Thirteen conventional asphalt spaces were also installed to serve as an experimental control.
The project also installed underdrains below each type of paving surface, allowing for testing of each material’s performance in achieving ground water recharge and pollutant removal. The parking lot collects a portion of the infiltrating stormwater below the surface, where it is piped to below-grade tanks for collection, measurement, sampling, and testing. Stormwater runoff from the conventional asphalt spaces drains into a six-cell rain garden where ORD intends to research rain garden sizing.
ORD intends to continue this research for up to a decade to help determine the effectiveness, durability, and maintainability of each surface type and the overall effectiveness of permeable pavements.
Light emitting diode (LED) fixtures were incorporated into the parking lot site lighting. LED fixtures consume less than half the power of traditional metal halide fixtures but provide similar lighting levels and require less maintenance and replacement.
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Edison’s parking lot was also upgraded with a rain garden.