Construction Equipment Guide: On the southern tip of Staten Island, New York City's latest project to address climate change is now slowly rising from the sea.
In September, the Governor's Office of Storm Recovery announced that crews had started work on the Living Breakwaters, a series of eight enormous rock piles that are being installed off the coast of Staten Island's Tottenville neighborhood.
When the $107 million project is complete in 2024, it will stretch along a mile of shoreline, blunting the impacts of waves, erosion, storm surges and sea level rise — while also providing an important habitat for marine species.
The news website Gothamist reported that from a 250-ft.-long barge moored in the shallows of Raritan Bay, workers are slowly and methodically placing more than 1,100 stone-filled mattresses into the water, creating a foundation for the first two breakwaters. Each 22-ft.-long marine mattress, held together by a geosynthetic mesh and weighing about 7 tons, is gently lowered into the bay by an equilibrium crane and guided into place by underwater divers.
"They get installed in kind of a jigsaw puzzle, [or] Tetris formation, where they are all side-by-side, up against each other," explained Kevin Robinson, project manager of Weeks Marine, the Cranford, N.J.-based construction and dredging contractor performing the work.
"That provides scour protection and a structural foundation for the stone, so it doesn't settle into the bay and collapse over time."
The New York landscape architecture studio SCAPE designed Living Breakwaters after winning funds from the Rebuild by Design competition, an initiative created by the U.S. Department of Housing and Urban Development in the aftermath of Hurricane Sandy. SCAPE also is coordinating the entire construction process.
The breakwaters under construction will include hundreds of specially designed concrete features that mimic tide pools and marine habitats, Gothamist reported. The four largest of the structures also will create reef ridges extending into the bay, providing shelter for fish and other marine life, including an oyster colony installed by the Billion Oyster Project, an initiative dedicated to restoring those habitats to New York Harbor.
The last step in the breakwaters project will be a beach replenishment, spreading 21,000 tons of newly dredged sand across the Tottenville shoreline.
Tottenville's coastal area is in dire need of protection as it has become badly eroded over the last few decades, and waves now crash just a few feet away from the lawns of waterfront homes.
The neighborhood was inundated by the hurricane's storm surge, which destroyed homes, cars and businesses.
After Sandy crashed along the coast in 2012, a barrier of sand filled TrapBags was installed. Since then, however, hundreds have split open, emptying their contents back onto the ocean. Where this barrier ends, homes are protected by little more than loose piles of rubble.
"There were a number of houses that were just obliterated [by the hurricane]. The first line of houses was the wave break," said Pippa Brashear, the planning principal at SCAPE, and project manager for the Living Breakwaters. "The aim here is to take that offshore. The breakwaters are designed to be high enough, but also strong enough, that those big waves are breaking out there on the breakwaters, and not reaching shore."
Beginning in January, the breakwaters will start to emerge from the water, she told Gothamist, as workers place larger stones onto the completed mattress layers. These materials are being quarried in Johnstown, N.Y., where each stone is inspected by the construction team's geologist, before being floated down the Hudson River in barges.
When construction is finished, the top 7.5 ft. of the largest breakwaters will be visible at mean tide. Navigational lights will be placed on top to prevent accidents with boats and jet skis. Read more>>