'Living Shoreline' Proposed: Man-made Marsh Would Protect Eroding $3.9M Property

By: Tim Wood

Topics: Erosion

A man-made marsh system is being proposed to protect this Chatham Harbor coastal bank from erosion. TIM WOOD PHOTO

CHATHAM – After the state refused to allow them to build a revetment to protect their $3.9 million home, a Shore Road couple is proposing an innovative shoreline stabilization project that could serve as a state-wide model.

Lisa and James McGonigle are seeking permission from the conservation commission to install a “living shoreline” at the base of the coastal bank at 498 Shore Rd. The project involves the creation of a 140-foot-long man-made marsh, anchored by eight- to 12-inch cobblestone, to stabilize the beach, with a row of fiber rolls above to hold the bank in place.

While this form of shoreline stabilization is used extensively in the Mid Atlantic states, it is relatively new for Massachusetts and could provide erosion protection for homes, like the McGonigles', that were built after 1978. Under the state Wetlands Protection Act – and the town's local wetlands bylaw – coastal engineering structures such as rock revetments cannot be used to protect homes built after that date. A rock revetment to protect the McGonigles' coastal bank was previously denied.

The key to the proposal, said Director of Natural Resources Dr. Robert Duncanson, is that state and town officials have agreed that under the state and local wetlands laws, it isn't a coastal engineering structure.

“It's somewhat novel, but it really does not meet the true definition of a coastal erosion structure,” he told the conservation commission earlier this month.

With erosion of the coastal bank continuing this past winter, the McGonigles find themselves “between a rock and a hard place, no pun intended,” said their attorney, Sarah Turano-Flores. They believe the living shoreline proposal is their best hope for erosion protection. The project has been in the works for six months, and the owners are “beyond hopeful that this is going to succeed,” she told the commission.

“We strongly feel this is the next best option” to a rock revetment, she said.

A 108-foot rock revetment was approved by the conservation commission in September 2014, but the decision was appealed by a group of 10 residents and by the state DEP, which eventually overturned the local approval. After several appeals, DEP Commissioner Martin Suuberg upheld the denial in 2017, citing the fact that the McGonigle home was built in 1986 and that the coastal bank was a significant source of sediment for nearby beaches. The McGonigles' appeal of that decision is currently pending in Barnstable Superior Court.

State Department of Environmental Protection spokesman Ed Coletta said the agency had offered feedback on the living shoreline plan and agreed it did not constitute a coastal engineering structure. He declined to comment further due to the pending litigation.

Members of the conservation commission were receptive to the living shoreline proposal.

“This is a very interesting application,” said member DeeDee Holt, one of the 10 residents who filed the initial appeal against the rock revetment. While chairman Michael Tompsett concurred, member Joseph Scarlatelli was skeptical that the combination of fiber rolls and man-made marsh would provide the sought-after erosion protection. Previous fiber rolls at the location did not work, he noted.

“I just see this as another fiber roll array that mother nature is going to make very short work of when one of those real violent storms comes whipping into Chatham,” he said. He supported the original revetment proposal and said even a smaller, four-foot revetment such as the one that exists south of the McGonigle property would provide better protection. It may be time to reconsider the rule that prohibit coastal engineering structures to protect homes built after 1978, he said.

That may be so, replied Tompsett, but “there's nobody in this room that can make that change.”

Town staff also had concerns about the proposal. Shellfish Constable Renee Gagne expressed concern in a letter to the commission that should the structure fail, the cobble could disperse into nearby resource areas and interfere with the natural movement of sediment. Coastal Resource Director Ted Keon said he was concerned about the survivability of the proposal given the beating area can take during northeast storms.

“This portion of Chatham Harbor is dynamic with relatively high energy during storm events, and it may be difficult to establish a viable and sustainable high marsh buffer along this coastal bank,” he wrote in a letter to the commission. Strict monitoring and maintenance will be necessary if the proposal is approved, he said, and he recommended that should the project fail or be deemed unsuccessful that it be completely removed.

Regular monitoring and replenishment of sand is part of the proposal, said Turano-Flores. Duncanson said the structure will be inspected after coastal storms. The commission is likely to impose a condition along the lines of what Keon suggested, said Tompsett.

Seth Wilkinson of Wilkinson Ecological Design, which developed the proposal, said it provides two layers of erosion protection for the bank, with the marsh stabilizing the beach elevation and the fiber rolls protecting the upper bank against higher tides and storms. He noted that there is marsh just north of the McGonigle property, and there was degraded salt marsh there when they purchased the property in 2001.

The goal of the project is really to create a layer of peat that can anchor the beach, Wilkinson said. In nature, that can take years, even decades; by using the cobble to anchor a mix of compost, coir fiber and sand, planted with beach grass, salt marsh hay, seaside goldenrod, spike grass and switch grass, they hope to speed up the process.

“It's sort of a placeholder to play that key role that the dead plant roots have in normal peat before you have had the plants growing long enough for the roots to die,” he explained. Similar projects have been done elsewhere, including in Stage Harbor, but the difference here is the cobble stones.

“I can't stand here and say 100 percent this is going to be successful, but I do think unquestionably we'll improve the site, we'll learn about the site, and we may have to come back in” and make adjustments, Wilkinson said. “Because it's not your typical project.” He assured the commission that the project will be closely monitored.

“Creating a salt marsh where one didn't exist before is probably more difficult than a restoration project, so I think it requires extra monitoring and vigilance to make sure that everything is done to help it survive,” he said.

The commission has drafted an order of conditions and a final vote on the project was on the agenda for this Wednesday's meeting, but Tompsett said that may be moved to the commission's next meeting on June 6.