How coconuts protect the Jersey Shore and other eroding shorelines
NEPTUNE, NJ (AP) — Coastal communities around the world are adding a tropical touch to shoreline protection, courtesy of the humble coconut.
From the sands of the Jersey Shore to the islands of Indonesia, strands of coconut husk, also known as coir, are incorporated into coastal protection projects.
The coir material is often used in combination with other measures and is seen as 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 instead of hard barriers of wood, steel or concrete.
One such project is being installed along a stretch of eroded riverbank in Neptune, New Jersey, about a mile from the ocean on Shark River. Using a mix of a federal grant and local funds, the American Littoral Society, a coastal protection group, is advancing the $1.3 million project that has already contributed significantly to what was previously a severely eroded shoreline in an area that was ravaged by Superstorm Sandy in 2012.
“We always try to reduce wave energy while shielding the shoreline, and whenever we can we like to use nature-based solutions,” said Tim Dillingham, the group’s executive director. “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 shells and spun into mats or logs, often held together with nets. In developing areas, discarded or torn fishing nets can be processed.
Its flexibility allows it to be shaped and shaped as needed on uneven sections of shoreline, held in place by wooden posts.
The coconut-based material biodegrades over time. But before it happens, it is sometimes pre-seeded with riparian plants and grasses, or those plants are placed in holes that can be punched into the coconut blocks.
The logs hold the plants in place as they take root and grow, eventually breaking off and leaving the established plants and sediment around them to stabilize the shoreline.
Coconut based materials are used all over the world for erosion control projects.
One is in Boston, where Julia Hopkins, an assistant professor at Northeastern University, uses coconut fiber, wood chips and other material to make floating mats to slow down the force of waves and encourage aquatic vegetation growth. A pilot project has four such mats in waterways around Boston. Hopkins envisions a network of hundreds or even thousands of mats linked together to protect larger areas.
She is satisfied with what she has seen so far.
“Coconut fiber is organic material, it’s relatively cheap and it gets thrown away,” she said. “It’s basically recycling something that would be thrown away.”
Two projects in East Providence, Rhode Island, used coconut blocks in 2020, and 2,400 feet (731 meters) of shoreline in New York’s Jamaica Bay that was eroded during Superstorm Sandy was stabilized in 2021 by a project that also included coconut trees.
Cape Cod, Massachusetts, did a similar project last year, and the Delaware Department of Natural Resources and Environmental Control is offering money to help landowners, homeowners associations and others build living banks made of materials that may contain coconut fiber.
A project in Austin, Texas has stabilized part of Lake Austin’s shoreline; monitoring from 2009 to 2014 showed reduced erosion and the healthy growth of native plants on the waterfront.
Indonesia is the world’s largest coconut producer, producing more than 17 million tons by 2021. Scientists from Bandung Institute of Technology’s Oceanography Program used coconut husk material to help build a seawall in 2018 in the Karangjaladri village of Pangandaran Regency.
Residents of Diogue Island in Senegal use wooden structures and coconut palms and sticks to reclaim eroded areas of the beach.
However, it doesn’t always work.
In 2016, the Felix Neck Wildlife Refuge in Edgartown, Massachusetts, on Martha’s Vineyard installed it near the Sengekontacket Pond, where a salt marsh had eroded several feet in previous years. While it helped reduce erosion for a while, the chaff didn’t last long because of the strong wave action.
“It has blown out several times,” said Suzan Bellincampi, the shelter’s director. “We had it for a few years and we decided not to install it again.
“The project was really interesting in terms of what we wanted to do and how we adapted it,” she said. “It’s not for every site; it must be site specific. It works in some places; it doesn’t work everywhere.”
Similarly, coconut fiber batts 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 Montreal’s Nuns Island, uses coconut mats to control the growth of invasive reeds along the shoreline.
At the New Jersey location a few miles south of the musical hotbed of Asbury Park, supplied sand has mixed with sediment from the tides to create a beach noticeably wider than what used to be.
“Under your feet are now hibernating violin crabs,” said Captain Al Modjeski, a restoration specialist with the Littoral Society. “They will be excited about this new habitat.”
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