Mordecai Island Projects Continue to Help Curb Erosion, Keep Land Thriving

Aug 31, 2016
File Photo by: Ryan Morrill Mordecai Island

Mordecai Island, a mile-long marsh situated along the Barnegat Bay shoreline at the south end of Long Beach Island near Beach Haven, has undergone more transformations during the past year than it has in decades. The alterations, led by the Mordecai Land Trust, have been conducted to help curtail the erosion of the island, which has dwindled over the years from 67 to less than 45 acres. The nonprofit group is dedicated to maintaining the land as a natural home for breeding and migratory types of native birds and fish as well as well as for shielding nearby Beach Haven from flooding.

“People don’t realize that those little marsh islands out there are really important,” said Linda Colgan, president of the trust.

For example, she said, the homes in front of Mordecai did not have as much damage as the other LBI houses impacted by Superstorm Sandy.

“It acted like a giant sponge and sort of sucked up the wave accretion that was hitting it. So it just softened the effect of that storm,” she explained.

Last fall, post-Sandy supplemental funds enabled the U.S. Army Corps of Engineers to contract Barnegat Bay Dredging Co. of Harvey Cedars for the relocation of nearly 30,000 cubic yards of bottom material, composed of 80 percent sand, from the New Jersey Intracoastal Waterway to a cut between the central point of the island and its northern tip. Colgan first stood on the new land in December.

“You feel like you’re in a whole different world out there; it was just wild,” she said. “It’s this beautiful, little beach, and all these birds were dropping their crab shells and walking along. I couldn’t believe it was open water just a month before that. It’s amazing. The island isn’t even that big, and it makes such an impact.”

Although a turbidity curtain was established on the eastern edge to secure the placed fill and a gently sloping beach was added to help absorb wave energy, filling in the cut wouldn’t be enough to keep it from eroding.

“You need something that’s pretty strong because it’s a harsh environment out there,” Colgan explained. “You can’t have something that’s going to just float along the surface.”

To add structure and strength to the region, salt marsh grasses found in the vicinity needed to be established. In late May, saltmarsh cordgrass was planted in the area with the lowest elevation, which normally gets covered during high tides, and salt meadow hay and saltgrass were planted in the area with the next lowest elevation. Fencing was also added to deter geese, which can destroy a newly planted spot in just hours.

The location with the greatest elevation and the least exposure to salt water was expected to be planted with coastal shrubs, but it was left untouched when officials found it to be a key nesting area for many shore birds.

“The plantings looks great,” said Colgan. “They were looking a little skinny at the beginning of summer, and now they’ve really taken hold. So it’s really turning into a nice marshland in that area.”

At the other end of the island, salt marsh grasses are starting to colonize where geotubes installed in 2010 have been gradually accumulating sand.

“We’re actually making land out there, so we’re making some new Mordecai. It’s great,” Colgan stated.

ReClam the Bay has added 25-pound bags of clam shells to various locations in the area to help support the growth of oyster bars and, in time, the rib mussels that fasten to them. Mussels, which help prevent erosion, grow naturally in the island’s intertidal zone, Colgan noted. The objective of the project is to determine the viability of constructing a man-nature-made reef system to help protect against erosion as well as to make the island an enticing environment for various saltwater organisms.

“We want to build a natural reef because they’ll be there forever and they build on themselves, almost like a coral reef in the Caribbean, to protect the island,” Colgan stated. “It’s the first time we’ve done it on Mordecai Island. So if it works here, it’ll be something for other islands to try. It’ll be a whole new living shoreline approach.”

The trust is also working to restore diamondback terrapin nesting sites on the island. This summer, Kathy Lacey of the Terrapin Nesting Project transferred many nests to the area that were found to have little hatching success on LBI due to human activity and predation. Cages to protect the relocated nests were set up to keep out predators.

The trust’s projects are ongoing and are, in many ways, experimental, Colgan said. Time and regular observation will tell how triumphant the efforts really are.

We’re like a little experiment because everything that we do has not been done before,” she stated. “It’s all about keeping the ecological system intact in Barnegat Bay because we feel like everything we do on Mordecai impacts everything in the bay itself.”

— Kelley Anne Essinger

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