Gravel Pavers Meet Requirements for Permeability, Storm Water Retention
Hurricane Sandy devastated the Atlantic Coast in 2012, causing significant damage to coastal communities in many Mid-Atlantic states. During the hurricane, wind and water surges breached barrier islands and coastal protection, causing unprecedented flooding that destroyed businesses, homes, trees, power lines and pavements.
A luxury car dealership in Brooklyn, N.Y., lost a protective bulkhead and land, sustaining significant damage to its asphalt vehicle parking area from the storm’s flooding. Total pavement reconstruction was necessary for fleet parking.
However, stringent new regulations put in place after Hurricane Sandy for flood-prone areas eliminated a completely asphalted surface as an option. New pavements were required to be designed so that all sheet flow was captured on site utilizing storm water detention systems.
New York Presto Geosystems representative Bill Ragen of Ragen Associates presented Presto Geosystems’ GeoPave aggregate pavers to the dealership’s project engineer and contractor.
Because rigorous everyday traffic was anticipated, the GeoPave pavers with aggregate infill were specified to provide a long-term porous surface over approximately half of the 2.5-acre parking lot; the remaining area was to be paved with asphalt.
Regulatory Approvals
The project superintendent and the general contractor visited a similar site where GeoPave pavement had been in use for four years with no maintenance. With both the owner and contractor convinced that the system was the right solution for this site, the project superintendent worked to obtain the necessary regulatory approvals. The system met all regulatory requirements and was approved by the New York State Department of Environmental Conservation.
Storm Water Infiltration & Retention
A deep base of 18 in. of varying-sized aggregate was designed under the GeoPave pavers for maximum storm water storage. The bottom layer consisted of 12 in. of ¾-in. aggregate, followed by a middle layer of 4 in. of ½-in., and the top 2 in. was a leveling layer of finer grain stone. Infill in the GeoPave units consisted of 0.375- to 0.5-in. aggregate with minimal fine content.
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GeoPave pavers confine open-graded aggregate, delivering high rates of infiltration to minimize storm water runoff. Water flows through the pavement layer into the storm water retention base layer for storage and ultimately natural percolation. The system’s molded mesh bottom keeps aggregate from moving, even under high vehicle traffic, and offers a stiff resistance to loading stresses.