Coastal erosion in the United States costs roughly $500 million in property damage annually. Proposed solutions focused on building higher, thicker, wider protective structures—such as seawalls—are expensive and exacerbate erosion. Engineers developed a resilient system of “living breakwaters” with geosynthetics that effectively and sustainably reduces storm damage while enhancing plant and marine habitat in the waters surrounding Staten Island, N.Y. The project broke ground on Sept. 21, 2021.
Engineers create living breakwaters using the Tensar International Corp. Triton Marine Mattress System of strong, flexible geogrids filled with limestone. The company fabricated the mattresses to address geotechnical issues at the site, like irregular land contours, variable subgrades, continuous scour and generally harsh conditions.
“The uniformity, strength, ease of installation, stability and porosity of the Triton Marine Mattress System makes them a fit for this project,” says Steve Williams, industry manager, marine and ports, at Tensar. “The strength of the mattress system makes it ideal for use on a subgrade like the seabed around Staten Island. The mattresses address toe scour protection, differential settlement, bearing capacity and global stability of the structure.”
In addition to dampening wave energy, the living breakwaters serve—just like their nature-made counterparts—as habitat for oysters, lobsters and juvenile fish. Triton marine mattresses are key to successful oyster restoration, as their filling provides the substrate for oyster growth. Oyster spat (larvae) incubated in repurposed, disinfected oyster shells from New York restaurants, are transported to and placed on the structure. There, they attach and grow to maturity.
MARINE MATTRESSES FOR SHORELINE PROTECTION
State of New York
Tottenville Beach, Staten Island, N.Y.
Weeks Marine Inc.
WSP Global Inc.
Triton Marine Mattress System
Tensar International Corp.
TenCate Geosynthetics Americas