NEPTUNE, NJ (AP) — Coastal communities around the world are adding a tropical flair to shoreline protection, thanks to the humble coconut.
From the sands of the Jersey Shore to the islands of Indonesia, strands of coconuts, known as coir, are incorporated into shoreline protection projects.
Often used in conjunction with other measures, coconut shell material is considered a cost effective, readily available and sustainable option. This is especially true in developing countries. But the material is also popular in wealthy countries, where it is seen as an important part of so-called “living coastlines” that use natural elements rather than hard barriers of wood, steel or concrete.
One such project is being installed along an eroded section of shoreline in Neptune, New Jersey, about a mile from the ocean on the Shark River. Using a combination of federal grants and local funds, the American Littoral Society, a coastal conservation group, is carrying out the $1.3 million project that has already significantly added to what was once a badly eroded shoreline in a area that was hit by Superstorm Sandy in 2012.
“We always try to reduce wave energy while protecting the shoreline, and whenever we can we like to use nature-based solutions,” said Tim Dillingham, the group’s chief executive. “This material is readily available, especially in developing countries, and it is relatively inexpensive compared to harder materials.”
Coir is made from the stringy fibers of coconut husks and woven into mats or logs, often held together by netting. In developing areas, abandoned or torn fishing nets can be incorporated.
Its flexibility allows it to be molded and contoured as needed on uneven areas of shore, held in place by wooden stakes.
The coconut material biodegrades over time, by design. But before that, it is sometimes pre-seeded with riparian plants and grasses, or these plants are placed in holes that can be drilled in the coco logs.
Logs hold plants in place as they take root and grow, eventually decaying and leaving established plants and the sediment around them in place to stabilize the shoreline.
Coconut materials are used worldwide for erosion control projects.
One is in Boston, where Julia Hopkins, an assistant professor at Northeastern University, uses coconut fibers, wood chips and other materials to create floating mats to dampen the force waves and encourage the growth of aquatic vegetation. A pilot project has four of these mats in the waterways around Boston. Hopkins envisions a network of hundreds or even thousands of interconnected mats to protect larger areas.
She is happy with what she has seen so far.
“Coir is an organic material, it’s relatively cheap, and it’s a waste product,” she said. “It’s actually recycling something that was going to be thrown away.”
Two projects in East Providence, Rhode Island, used coconut logs in 2020, and 2,400 feet (731 meters) of shoreline in Jamaica Bay in New York that was eroded during Superstorm Sandy was stabilized in 2021 by a project that also included coconut logs.
Cape Cod, Massachusetts, completed a similar project last year, and the Delaware Department of Natural Resources and Environmental Control is providing funding to help landowners, homeowners associations and others install living shorelines made of materials which may include coconut fibers.
A project in Austin, Texas stabilized part of Lake Austin’s shoreline; monitoring from 2009 to 2014 showed decreased erosion and healthy growth of native plants at the water’s edge.
Indonesia is the largest producer of coconuts in the world, with more than 17 million metric tons in 2021. Scientists from the Bandung Institute of Technology’s Oceanographic Program used coconut shell material to helping build a dyke in Karangjaladri village of Pangandaran Regency in 2018.
Residents of Diogue Island in Senegal use wooden structures and coconut leaves and sticks to salvage eroded sections of beach.
It doesn’t always work, however.
In 2016, the Felix Neck Wildlife Refuge in Edgartown, Massachusetts, on Martha’s Vineyard installed it at Sengekontacket Pond, where a salt marsh had eroded several feet in previous years. Although it helped reduce erosion for a while, the wraps didn’t last long due to the heavy wave action.
“It was blown several times,” said Suzan Bellincampi, director of the sanctuary. “We had it in place for a few years and decided not to reinstall it.
“The project was really interesting in terms of what we wanted to do and how we adapted it,” she said. “It’s not for all sites; it must be site-specific. It works in some places; it doesn’t work everywhere.
Similarly, coir mats and logs were recently used on Chapel Island in Nova Scotia, Canada, but were damaged by bad weather.
Another Canadian site, Lac des Battures, a lake on Nuns’ Island in Montreal, uses coconut mats to control the growth of invasive reeds along the shoreline.
At the New Jersey site, a few miles south of the music hotspot of Asbury Park, sand trucked in has joined with tidal sediments to create a beach significantly wider than previously existed.
“Beneath your feet right now are hibernating fiddler crabs,” said Captain Al Modjeski, restoration specialist at the Littoral Society. “They will be excited about this new habitat.”
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