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Case Studies  > Jordan Cove Watershed, Waterford, Connecticut
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Rather than being paved, the center of the culdesac in Glen Brook Green subdivision provides a bioswale to absorb runoff and overflow from the permeable pavement.
Runoff and pollution monitoring of permeable interlocking concrete pavements (PICPs) has demonstrated their benefits in the U.S. EPA funded Jordan Cove Urban Watershed National Monitoring Project. Driveways and a municipal street were paved in this low-impact, environmentally sensitive residential development. This watershed that drains to an estuary in Long Island Sound is participating in a 10-year monitoring project of runoff from a traditional subdivision, a single-family home development built with conventional pavements and stormwater management system, and a low-impact development built with runoff and pollutant-reducing BMPs. These include grass swales, bio-retention areas, and PICP.

The U.S. EPA Section 319 National Monitoring Program supports the monitoring project conducted by the University of Connecticut. Built in 2001, the Glen Brook Green subdivision within the watershed features over 15,000 sf (1,400 m2) of PICPs in a street and residential driveways that recharge the local aquifer, slow runoff velocities, oxidizes and filters some pollutants, filters suspended solids and cools water before it enters the estuary.

Maintenance includes periodic sweeping and vacuuming with the same equipment used on other streets. An annual inspection ensures no ponding and aggregate is replaced in the pavement openings as needed. The 2003 annual report of the multi-year monitoring project demonstrates the effectiveness of PICPs in reducing runoff and pollutants (1). Runoff quantity and quality from asphalt, PICPs (with a dense-graded base) and crushed stone driveways entering single family homes were studied for 12 months in 2002 and 2003. A plan of the neighborhood and driveway types is shown below.

Besides lower infiltration rates than asphalt, PICPs demonstrated lower concentrations of pollutants in runoff and similar concentrations to that from driveways with crushed stone. Table 1 shows the average infiltration rates from the surfaces in 2002 and 2003. Table 2 shows the average weekly concentration of pollutants in stormwater runoff for various pollutants. Concentrations are statistically signifi- cantly lower for all pollutants from PICP compared to asphalt. Pollutant levels in PICPs are similar to that from the driveways with crushed stone.

Typical cross-section:
3 1/8 in. (80 mm) thick permeable pavers
8 to 10 in. (200 to 250 mm) dense-graded base

Subgrade: Sandy gravel

Project Team
Developer: Lombardi Inside/Out L.L.C. Waterford, CT
Project Manager: Aqua Solutions East Hartford, CT
Engineering: D.W. Gerrick Engineering, Waterford, CT
Landscape Architect: John Alexopoulus University of Connecticut
Water Quality Monitoring: Dr. John Clausen University of Connecticut