BRUNSWICK — Two Brunswick sites have been selected as test locations for a five year, $1.5 million, New England-wide living shoreline study exploring the impact of using natural materials such as oyster shells and fallen trees to mitigate the impacts of erosion in coastal bluffs and protecting Maine’s dynamic coastal ecosystems. 

According to the Maine Geological Survey, a living shoreline is a relatively broad term that encompasses a range of shoreline stabilization techniques, in which the shoreline has a footprint made up mostly of native material, incorporates vegetation or other living “soft” elements and reduces erosion while providing habitat value and enhancing coastal resilience. 

Historically, Maine’s experience with living shorelines has been related to stream restoration activities, though there has been some work along the coast with dune restoration, construction and beach nourishment using dredged materials. 

But Maine’s sandy coast actually only accounts for about 2% of the state’s shoreline, and while Maine is often thought of as a rocky coast, more than 40% is erodible bluffs and mudflats, according to Peter Slovinsky, a marine geologist with the Maine Geological Survey.

These bluffs have seen increased development in recent years, and to help prevent against erosion, more and more have been stabilized by “traditional shoreline engineering methods” (known as armoring) such as installing a retaining wall or riprap— a process where tons of earth are removed and replaced by piles of boulders.

The process may protect property, but according to the Maine Geological Survey, “it can exacerbate erosion on neighboring properties, and over time, can result in loss of protected resources such as marshes and mudflats due to storms and sea-level rise.” 

According to Slovinsky, it is relatively simple to get a Department of Environmental Protection permit to put down riprap above the highest water line.

“The traditional thinking is, that’s wonderful (because) you’re not negatively impacting the resource balance,” Slovinsky said, “but a lot of (mudflats and fringe wetlands) derive their sediments from the erosion of the coastal bluffs… When you armor, you’re cutting off the supply of sediment from the uplands to the wetlands… You end up pinching out the resources we’re trying to protect.” 

What is harder to get, is support for living shorelines, Slovinsky said, which are not as popular in Maine and the rest of New England, due to the long ice season. 

This is what Maine Geological Survey, the Town of Brunswick, The Nature Conservancy, Brunswick Topsham Land Trust, Maine Coast Heritage Trust, Casco Bay Estuary Partnership and Maine Coastal Program and others are trying to change through this new pilot, a New-England wide effort funded by a 2017 $1 million Regional Resilience Grant from the National Oceanic and Atmospheric Administration and $500,000 matching from The Nature Conservancy. 

The concept is basically that “low-cost, beneficial reuse of naturally occurring materials can be used to slow down erosion at coastal marshes and bluffs,” Slovinsky said, and officials will use oyster shells (about 35 cubic yards worth) and tees to test their hypothesis. Maine has selected three sites to test these methods, two of which are in Brunswick. 

Wharton Point and Maquoit Bay Conservation Lands were selected in part because of their accessibility, visibility to the public, educational opportunities, and influence of tides, waves and ice, but also because geographically, they represented larger parts of Casco Bay. 

At Wharton Point, organizers and volunteers will put half of the oyster shells in customized coconut-fiber bags and half in Tensar Georeef synthetic baskets, below the highest annual tide. The two materials will later be compared by how the materials held up in Maine’s harsh climate and how efficient they were in slowing bank erosion. 

At Maquoit Bay Conservation Lands, the demonstration will be very similar, but with the addition of “tree runners,” which use tall tree trunks to provide a ramp for ice to ride up and over the installation during the winter months, according to the project description. 

At the third site, on Yarmouth’s Lanes Island, crews will regrade a “highly unstable” eroding bluff to a more stable slope. Some trees, which are currently about to fall over, will be removed, cut and arranged into a step-like terraced crib structure, according to the geological survey. Root wads from the trees and sediment from regrading will be used to fill the terraces, and each will later be planted with salt-tolerant vegetation. This project will require more heavy equipment, like a barge and a backhoe.

Construction and installation at all three sites is expected to begin in late April or early May and the sites will be monitored for five years. The data will then go into a regional database being built with the other New England states. 

Slovinsky said Brunswick has a “colored history as it relates to armoring,” he said. Most notably, in 2016, Robert and Nancy King had the trees along more than 600 feet of waterfront cut as part of a shoreline stabilization project on their property on Miller Point in Brunswick. The shoreline was then lined with riprap.

Many residents were upset that no local review for the clear-cutting was required under the local ordinance. Town Attorney Stephen Langsdorf later found that although that was true, Brunswick’s regulations were out of compliance with state law. 

Since then, town officials developed an ordinance to bring the town back into compliance. The issue, though, according to Slovinsky, “got the town interested in armoring and coastal erosion (and) making sure (all) of our shorelines don’t get armored.” 

“Miller Point was a big catalyst for this project,” said Jared Woolston, town planner. 

Right now, there is relatively little movement on the project. Oyster shell is currently being “seasoned” in town, meaning that the used shells are being kept outside, in the sun as much as possible, for at least six months to rid them of any bacteria, disease or contamination before putting them in the water. The oyster shells were donated by the University of New Hampshire.

In the spring, Slovinsky and the town will gather volunteers, ideally commercial harvesters, high school and college students, to help fill the approximately 350 oyster bags so the living shoreline can be installed. 

Admittedly, the oyster reefs won’t work in all locations and where they do, they will require more maintenance than riprap or a retaining wall might, but nobody will be “putting down a hard boundary in the middle of this dynamic environment.” 

“Nobody has tested this stuff in Maine yet. There are no guarantees, but we’re really excited about testing it,” Slovinsky said. If it doesn’t work, it would certainly, “be a bummer,” he said, “but we would know we have to go back to the drawing board.” 

The work complements Maine’s current efforts to combat climate change, he said. As sea levels rise and storms increase, “we’re not going to be able to armor our way out of this problem,” he said, “so it fits into the larger context.”

Woolston agreed. It is exciting that two of the three sites are in Brunswick, he said, but if the work is successful, it could have larger implications for Maine and the rest of the region. 

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