Permeable pavers have been a key addition to a different kind of park: the North Shore Public Access Park on the Kill Van Kull, a tidal strait between Staten Island, NY, and Bayonne, NJ.
This waterfront park will transform a former industrial marina into a graceful passive-use park for local residents.
“It definitely was an underutilized piece of open space that needed to be developed as a waterfront park,” says Alex Berryman, RLA, principal landscape architect at The RBA Group, an engineering and landscape architecture firm in Manhattan, who oversaw most of the landscape design.
“The intent was to provide public waterfront access, a place where people could take in the sights of the Bayonne Bridge in the distance while watching the huge container ships glide by on the Kill Van Kull. It’s one of the few areas in the northern part of Staten Island where people can get close to the water.”
Two refurbished channel markers stand at the entrance to the 2.65-acre waterfront park. The park includes a flat recreational lawn, native vegetation, an ADA-accessible perimeter path paved with asphalt and concrete, and two parking lots paved with concrete Unilock Eco-Priora pavers. The edge of the park is fenced off with a semi-transparent grill panel fence to prevent visitors from accessing the abandoned docks and shoreline.
One of the parking lots holds eight cars. The second, a 12-car lot with a turnaround, is on the park grounds and can be gated off and used as a plaza to host public events. The RBA team chose permeable pavers for both parking lots to minimize the impervious surfaces and to mitigate excess runoff. The project complies with the state stormwater requirements, Berryman says.
“The reason we used the Unilock Eco-Priora is because they’re designed for plazas as well as to take the weight of vehicles. The narrow [three-eighths of an inch] gap between them is compatible with pedestrian use, so the surface is very smooth for pedestrians to walk on.”
The funding for the park comes from the Port Authority of New York and New Jersey, through the Trust for Public Land (TPL), a nonprofit dedicated to land conservation. The land itself is owned by the New York City Department of Parks, which will maintain the park once construction is complete. The TPL hired The RBA Group to perform both the design and the engineering of the project.
The entire project began in the fall of 2012 and was completed in September 2013.
The RBA team designed the site grading to maintain the existing stormwater surface runoff patterns to the Kill Van Kull, which avoided the need for costly subsurface drainage systems, Berryman says. They also mitigated the effect of the park’s asphalt and concrete paths without adding drainage pipe by designing the aggregate in the parking lots to be at least 14 inches deep.
“The aggregate layer provides space for water storage as well as spreads out the point load,” Berryman says. The paver systems in the two parking lots will be able to store approximately 6,300 cubic feet of runoff.
The general contractor, Fredante Construction Corp. of Cold Spring Harbor, NY, did a very good job installing the paver system, says Sean O’Leary, vice president with Unilock New York Inc.
Crews placed a geotextile drainage mat at the bottom of the excavation to strengthen the sub-base and improve the bearing capacity.
Above that, they placed an 8-inch layer of No. 2 stone, a 4-inch layer of No. 57 stone, then a 1.5- to 2-inch layer of No. 89 stone. They compacted each layer.
They laid a total of 14,000 square feet of the Unilock Eco-Priora permeable pavers with a Series 3000 (exposed aggregate) finish and put No. 8 or No. 9 stone between the pavers.
For maintenance, O’Leary says that sweeping the parking lots twice a year, once after the leaves have fallen and once in the spring, will lift up the particles on top of the pavers and the joints.
“The advantage of this system is if there’s a small amount of localized clogging, runoff is still going to flow through the adjacent and surrounding joints. We see a lot of permeable paver installations with little to no maintenance, and they’re still performing very well. If clogging worsens, you can wait and remove the top half-inch or inch of chip stone and replace the clogged stone with new material. Even with little maintenance, you can still have a new permeable system by replacing the joint stone without ever having to take the pavers out.”