'Living' shorelines help guard Long Island coast against ravages of storms

An unusual kind of shoreline is taking root where failed bulkheads once lined Patchogue’s Shorefront Park off the Great South Bay.

Shallow basins crowded with milkweed and blooming goldenrod capture stormwater running down from upland, capturing sediment and pollutants before the water drains into the bay. Beyond the basins is a strip of salt marsh, sparse now but expected to thicken over the next year, providing habitat to birds and a natural shock absorber for waves in a severe storm.

Protecting it all, within what is known as a living shoreline, is a low sill of massive stones, parallel to the shoreline and partially submerged in the water, providing a first line of defense against waves and a home for marine life in its crannies.

Shorefront, designed by VHB Engineering and finished in September, is one of the newest and biggest projects executing a strategy that has been used for decades to stabilize shorelines along the Chesapeake Bay, the Gulf states, Australia and Europe. 

Living shorelines use natural elements alone or in combination with structural components. They are built to control erosion but also to provide some of the benefits of a natural shoreline. They are costly and require expert design. But, according to the National Oceanic and Atmospheric Administration, they are more resilient against storms than bulkheads, which can create seaward erosion and prevent marsh migration, a survival response to sea level rise.

Shoreline projects ongoing on Long Island

There are at least 12 such shoreline projects in New York, state environmental officials say. Besides Patchogue, they include public projects in Riverhead, Baldwin, Southold, the Shinnecock Nation and Westchester County. East Hampton officials plan at least two in Montauk. A shoreline built to protect eight properties on Dune Road in Westhampton Beach is likely the first private project on Long Island, according to its designer. Another private project, still in permitting, will protect 12 nearby properties. 

More may be on the way: A law signed in September by Gov. Kathy Hochul requires the state Department of Environmental Conservation to adopt policies and regulations to establish the approach as the “preferred alternative” for stabilizing tidal shorelines.

State Sen. Shelley Mayer (D-Westchester), who sponsored the bill, said it was a response to constituent demand after severe storms like Sandy and Hurricane Ida displaced hundreds of people in her district. “In the communities I represent along the Sound, there’s such a strong sense that we need to do everything we can to deal with flooding,” she said.

Patchogue's “looks great — people come down here all the time to walk their dogs, ride bicycles — and more importantly, this will provide protection against storms like Sandy and major rainstorms,” village Mayor Paul Pontieri said.

Superstorm Sandy’s flooding damaged nearby houses, but the area was vulnerable even to lesser events. Heavy rains near Christmas last year failed to drain and turned to ice, cutting off a nearby restaurant, Lombardi’s on the Bay, before workers chipped access paths, Pontieri said. The project cost roughly $5 million and included extensive upland work, including elevating a grassy swath of the park by several feet to improve flood resistance.   

VHB tried to reproduce the variety and abundance of a natural shoreline by planting 57,041 plugs of sea grass and seven varieties and 5,810 shrubs and other plants in the basins, said project manager Carlos Vargas. “Even during construction, we saw a lot more shore birds moving in. We saw schools of small fish in high tide. In the little creek I saw a blue crab … In September, I saw an American eel.”

Marshes a natural storm barrier

Much of Long Island's natural shoreline was once wetland marsh. But between 1974 and 2008, according to the DEC, Long Island estuaries lost 2,758 acres of marsh area on their shores, a 13.1% decrease attributed to factors including sea level rise, erosion, invasive species.

The benefits of a marsh — whether naturally occurring or planted — are considerable. According to NOAA, one square mile of salt marsh secures the carbon equivalent of 76,000 gallons of gas annually, sequestering carbon dioxide that would otherwise help warm the climate. A 15-foot strip of marsh absorbs up to half of incoming wave energy. Marshes also trap sediment, rising along with sea level, and the grasses that make up a marsh are remarkably adaptive. 

Grass that grows 3 feet high on Long Island’s South Shore grows to 7 feet on Long Island Sound to match higher tides. “As long as you have a stable environment with wetlands, it will grow vertically,” said Aram Terchunian, a coastal geologist whose Westhampton Beach firm, First Coastal, worked on Suffolk County’s Indian Island Park project in Riverhead and on the private Westhampton Beach projects. 

Marsh, and the rocky sills featured in many living shorelines, are far more biologically productive than a sand beach, or one armored by a sea wall or bulkhead, Terchunian said. Marsh houses mollusks and insects, which attract birds. Rocks provide hiding places for juvenile fish and more surface area for algae and mollusks to encrust. “It’s a food web,” Terchunian said. 

Mollusks like oysters and mussels also clean the water as they feed. The Cedar Beach Creek project in Southold, a collaboration between Peconic Estuary Partnership, local government and Cornell Cooperative Extension, was built as a demonstration and uses the hardy ribbed mussel — common to Long Island waters but rarely eaten — to fertilize and toughen the salt marsh where it grows, said Barry Udelson, an aquaculture specialist, formerly with Cornell and now at New York Sea Grant.

At Indian Island, a $2 million living shoreline project now weeks away from completion was prompted in part by the erosion that in the early 2000s uncovered an American Indian burial ground. 

The funneling action of Great Peconic Bay during Nor’Easters and wave energy generated over the long fetch of open water across Flanders Bay caused erosion that averaged 3 feet a year and reached as much as 20 feet in some storms. 

“We tried for years placing sand and it would wash away,” Suffolk County Parks Commissioner Jason Smagin said. “We were looking for a permanent fix.”

Twenty-five years ago, even 10 years ago, “We would have bulkheaded this,” said Nick Gibbons, chief environmental analyst for county parks. “The science hadn’t evolved to look at new ways of solving problems.”

A bulkhead would likely have meant continued scouring and no salt marsh, and its engineering is difficult to modify. By contrast, a living shoreline can be modified, up to a point, simply by adding rocks to the rock sill.

Suffolk’s project was minutely engineered at a massive scale. For months, 16 trucks a day hauled in a total of 11,040 cubic yards of sand, 3,200 tons of granite and 27,050 plugs of sea grass. Then, said Steven Vecchia, from Woodbury-based D & B Engineers and Architects, which worked on the job, the sand was graded into a bluff and held fast by a layer of jute mesh topped by the sea grass, whose spreading roots will maintain the bluff’s shape. A machine operator placed rocks in two sizes — smaller ones from 100 to 300 pounds and larger ones from 800 to 1,200 pounds — in interlocking fashion to build the rock sill solid enough to withstand decades of wave and tide action. 

“The guy who does this is like an artist” using a GPS-controlled backhoe bucket instead of a brush, Vecchia said. “He’s sitting there, puzzling it out.”

Breaks in the wall, similar to those at Patchogue, let sediment-bearing water flow in. The rocks capture the sediment as the water flows out.

In one of the first texts to lay out the principals of living shoreline strategies, “Shoreline Management in Chesapeake Bay” (1999, Virginia Institute of Marine Science), C.S. Hardaway Jr. and R.J. Byrne describe a changing shoreline that might be familiar to Long Islanders: increasingly developed, denuded of fringe marshes that once provided protection and in many places in retreat because of sea level rise and wave action. Ironically, shoreline armoring by bulkhead and other methods, popularized both there and here in the middle of the last century contributed to that retreat, they write, closing off the supply of sand from protected areas and sometimes accelerating loss from neighboring unarmored areas.

When waves hit an armored shoreline, “That structure is bouncing energy in both directions,” said Alison Branco, climate adaptation director for the Nature Conservancy in New York. “You end up with this kind of arms race” as residents, unwilling to lose increasingly valuable waterfront land, join their neighbors in armoring. 

Appetite for armoring increased in the 2000s, especially after Sandy, she said, when permits “ramped way up and there were so many people with so much damage.” 

Challenges, costs of living shorelines

Some experts interviewed for this story said living shorelines cost more per square foot than shoreline hardening, but according to NOAA, living shorelines tend to cost less , with installation costs ranging from less than $1,000 to $5,000 per linear foot. Maintenance typically costs less than $100 per linear foot annually. 

Living shorelines might appear to offer a promising alternative, but even advocates say there are challenges. "Everything is site-specific,” said Hardaway, who consulted on the Patchogue project. "The more open water, the more wave energy you have, the more rocks you have to use.” Joyce Novak, executive director of the Peconic Estuary Partnership, said several projects on Long Island, including one at Widow’s Hole in Greenport, failed because they didn't anticipate wave energy. 

“There’s a huge lack of knowledge” about living shorelines, she said, along with flat-out fear from many homeowners who lived through Sandy. “Everybody remembers that like it was yesterday,” making some unwilling to put their trust in a solution with little local history. 

Several advocates said they hoped the September law would speed up permitting times that, in Patchogue’s case, stretched to years. That process can involve a bewildering array of agencies including the Army Corps of Engineers, New York State Department of State, New York State Office of General Services and the DEC. In an email, DEC spokeswoman Samantha Rosen said that design and approval for a natural shoreline “requires greater attention to natural details such as light, wave energy, tide heights, etc., than a standard bulkhead would."

Some are deeply skeptical. In Baldwin, Bonnie and Richard Weinstein said construction of a living shoreline in Baldwin Park across the canal from their Bertha Drive house had destroyed trees and habitat for hawks and other birds, and that after removal of bulkheading, so much earth slumped into the canal it was unnavigable except at high tide. Karen Montalbano, government liaison for the Baldwin Civic Association, called execution of the project “troubling” and said her organization was disturbed that park access was still restricted. Bids for the project were awarded in 2021.

In an email, Casey Sammon, a Hempstead Town spokesman, said the town involved itself in what was originally a Governor’s Office of Storm Recovery project after the project manager said it could not complete the job within its $3.1 million budget. The town has been waiting six months for a DEC permit to reinstall some of the bulkheading, he said. While 30 trees were removed during construction, 110 new ones were planted. Some “weren’t able to establish themselves” due to flooding from a storm last December, he said. 

Against a backdrop of sea level rise, there is also a question of usable life. NOAA’s intermediate low scenarios project sea level rise of close to 2½ feet by the end of the century in Port Jefferson and Montauk. The high scenario is for more than 6½ feet in those locations. 

“Seventy-five thousand homes will be in chronic flooding by the end of the century,” said Branco. “A living shoreline wouldn’t mean those people can stay in their homes. It can buy you a little more time, but eventually the water will come up so high, it doesn’t matter what’s on the shoreline — the whole property will go under water.”