The section of the Island’s seawall that takes the most pounding from the often stormy waters of New York harbor was originally a retaining wall, built as a boundary for the Lexington Avenue tunnel debris landfill that doubled the size of the Island. Now rounding out its first century, it’s about to get a economically and ecologically minded facelift.
Rehabilitation of the entire seawall, all 2.2 miles of it, is an essential element of the two-year phase of capital improvements that begin in the Spring – developing the park area, bringing in potable water, stabilizing historic houses and more.
Most of the wall needs repointing at least, and some of it needs replacement. There are also dozens of redundant “outfall” holes to be filled. These are holes in the seawall that drain accumulated water, mostly rain, into the harbor. They also cause problems in reverse, letting harbor water flow in, which is why they’re going to be filled.
And then there’s the ‘facelift’ installation of riprap along the western edge of the Island south of Division Road and the historic district, and all the way down and around the southern curve. Riprap means rocks, lots of them. Their function is to break the force of incoming waves, rather than letting each new wave score a direct hit. Also, riprap costs less than building a wall.
Lest anyone be tempted to climb out on the rocks, forget it. The guard rail that girds the full length of the Island’s perimeter will be there to deter adventurers. Wave action generated by a long stretch of open water makes this western edge particularly unsafe.
But the wide surface area provided by the jumbled rocks, and crevices in-between, make it ideal for all sorts of harbor creatures, from algae to mollusks to the fish they attract. The Harbor School has expressed interest in seeding the riprap with oysters and other marine species. The school already maintains a small oyster breeding project near the National Monument dock on Buttermilk Channel. Of course the whole project, including the restoration, is subject to state and federal approval.
Design for the complete seawall project is not yet final, and the official R.F.P. – the request for proposals by prospective contractors – will be issued in the spring.