The sea is rising, and so is the angst for coastal homeowners

Protection is needed against the wind and waves, but do sea walls and natural solutions really work?
A gray sea wall comprised of rock chunks lines the yard of a house in Bar Harbor.
A seawall on a bluff in Bar Harbor. Long lawns with large trees are one of the worst ways to manage erosion on a bluff, said Peter Slovinsky, a marine geologist with the Maine Geological Survey, but it’s often difficult to dissuade homeowners who prefer the views and the aesthetic. Photo by Kate Cough.

Before Walt Dunlap moved in 2011 to the shores of Maquoit Bay, just south of Brunswick, he did his homework. A licensed land surveyor, Dunlap knew the steep banks sloping down to the ocean were unstable and prone to erosion. The house stood just 30 feet from the top of the bank, and Dunlap, who left South Carolina to escape a rising sea, “just wanted to make sure that we had something that was not going to disappear overnight.”

Dunlap surveyed the Freeport property himself, using 1947 maps as a baseline. The top of the bank hadn’t moved, and while he knew erosion at the bottom was possible, the lower bank was camouflaged by dense foliage and vegetation, making it difficult to see just how much the soils were crumbling. The Dunlaps signed the papers, came up seasonally for a few years, then moved full time in 2015.

The more time they spent, the clearer it became: The bottom of the bank was slipping into the ocean. The shallow bay, exposed to the prevailing southwesterlies, was battered by increasingly intense winds and storms; waves gouged out the bank from below, while heavier and heavier rainfall pushed the soil down from above. 

“We didn’t appreciate that there might be a problem.”

The cycle of shoreline erosion is a natural process that has been going on as long as there has been land and sea: Bluffs and dunes crumble, feeding their soils and nutrients into the mudflats and marshes below. The shoreline shifts landward, stabilizes for a while, then wears away again.

“Erosion leads to stability leads to erosion leads to stability — the overall trend is this feature moving landward in response to sea level rise,” said Peter Slovinsky, a marine geologist with the Maine Geological Survey who has advised communities on how to deal with an encroaching ocean for more than a decade.

The problem arises when humans build barriers to that movement: homes, walls, ice cream shacks, boardwalks, hotels. Solid, immovable structures, like the seawalls and bulwarks scattered along the state’s bluffs and beaches, make the problem worse — waves hitting the wall reflect down and up, scouring out sand and soil at the base, and around the edges. As a result, water in places with walls is much deeper, and “because the water’s deeper, you can get much larger waves there,” said Slovinsky.

Two types of “gray” seawalls. The state is encouraging homeowners to implement greener solutions to protect their properties from the sea, such as native plantings and strategically placed rocks and logs. Photo by Kate Cough.

Walls, which have to end somewhere, also accelerate erosion around their edges. “Because this is now eroding, the property over here says I need a wall, then the next one, then the next one, then the next one,” said Slovinsky. “So it’s kind of a perpetual problem.”

Figures are hard to come by, but those who work along the coast say they’re seeing more and more homeowners armoring their properties against erosion with everything from native plants and strategically placed rocks to large granite walls and bulwarks.

When the Dunlaps noticed in 2015 they were losing the bottom of their bank, they immediately set about remedying the problem. The couple hired a landscaping company with experience in shoreline stabilization; the company ripped out the invasive vegetation that had grown up along the bank, and replaced it with 100 native plants and an engineered, porous fabric to help keep the soils in place. The Dunlaps own about 50 feet of shoreline; the plantings and permitting cost roughly $12,000, said Dunlap — money the couple was willing to spend as long as it helped keep the sea in the bay and not their living room.

Walt Dunlap hired a company to install engineered fabric and native plants to try and stop erosion at his property in Freeport. The fix is “working well,” said Dunlap, but requires some maintenance and isn’t preventing erosion at the bottom of the bluff. Courtesy photo.

What the Dunlaps did — planting native plants — is precisely the kind of fix the Maine Department of Environmental Protection would like to see coastal property owners implement against erosion. The plantings were part of a “living shoreline,” a system designed to shore up the bank while allowing some soil to fall away, feeding the wetlands or flats below, while not exacerbating the problem in the way walls or bulwarks do. 

Except, say engineers, living shorelines often don’t work — at least in Maine, with its strong winds and powerful tides.

“There’s not a lot of places that I see on the coast of Maine where the softer approaches work,” said Bill Walsh, founder of Walsh Engineering Associates, which designs solutions for homeowners to control erosion up and down the coast.

“We have too much wave energy and too much action on our shoreline,” Walsh continued. “I understand where the (Maine Department of Environmental Protection) is coming from, and that that’s where most people want to be environmentally, but I haven’t seen one that’s worked.”

The idea behind living shorelines is to mimic the natural environment, working with nature, not against it. Experts refer to shoreline stabilization techniques as “green” or “soft” — mostly plants and soils — or “gray,” the harder structures like walls and stone. What works in one spot may not work in another — designs depend on a long list of factors, from the prevailing winds and shape of the land beneath the ocean to whether the soil is clay, dirt or rock. 

Slovinsky points to projects farther south, in North Carolina and Maryland, where “softer” approaches — piling logs on a beach to trap sand, for instance — have been successful for decades. Maine is trying just that at Popham Beach, where a number of dunes were swept away during a December storm. It’s too soon to tell how lasting it will be, but the logs, which Slovinsky helped place, were already trapping sand less than a week later.

“There’s already some little ridges forming” from what was once a flat beach, said Slovinsky. 

There are state parks in North Carolina, he said, where for decades old Christmas trees have been piled along the shore to trap sand – a design Maine is considering at Willard Beach in South Portland, which also saw extensive erosion this winter. “It’s very, very effective in areas where you get a lot of wind-blown sand,” said Slovinsky. 

While there’s “always a chance another storm is going to come this winter and wipe these all out,” said Slovinsky, seawalls made of concrete or stone may not fare much better. “Just go down to Wells after the December storm. There are blown-out seawalls all over the place.” 

The plantings on the Dunlaps’ property worked well in stabilizing the bank for a few years. But the bottom of the bank continued to erode and in 2019, the couple hired a contractor to design something more substantial, with rocks at the bottom, to help stem the flow of soil to the bay.

“The estimate was $35,000,” said Dunlap, “and that’s a few years old now.” The DEP also suggested that the couple may need core samples taken to further determine how the bank was eroding. “At that point we decided this is not going anywhere,” said Dunlap. “Not with the amount of time, trouble and money it’s going to cost.”

Even if they fixed their portion of the bank, it was just a 50-foot stretch in 1,000 feet of unstable shoreline, Dunlap reasoned, which meant they’d need to work with property owners around them to come up with a more lasting fix. “We were too intimidated by the process going forward to do anything more substantial.”

The process can be complicated, especially for property owners looking to put something in where before there was nothing. While those who already have seawalls are allowed to rebuild them through a simple permit-by-rule process, the state generally prohibits constructing new seawalls on sandy beaches, and discourages them on coastal bluffs, which make up 48% of Maine’s coastline.

Slovinsky would like the rules around bluffs to be tightened and more explicit to further encourage more natural solutions, in part to save the state’s tidal wetlands, which are at risk of drowning as walls are built that cut off their supply of sediment. 

The state’s regulations are geared toward protecting the intertidal zone, said Slovinsky. “What these standards don’t take into account is that the marsh or mudflat needs erosion of that bluff to sustain itself. If you cut off the sediment supply, the resource we’re protecting is going to go away anyway.” 

The state does have standards that say homeowners can’t have an “unreasonable impact” on the supply of sediment to an adjacent wetland. 

“But what’s really unreasonable?” Slovinsky asked. “Think about it in context of an eroding cove that’s got wetlands and mudflats in it. One house in that cove puts a wall in — that’s not really unreasonable. Two houses, three houses, four houses, five houses, six houses — next thing you know the whole cove is armored and the supply of sediment to that resource we’re trying to protect is cut off.”

A wall under construction on a bluff in Bar Harbor. Photo by Kate Cough.

The state can’t easily pull out figures for how many permits have been issued for seawall repair or construction over the years — they’re lumped in with permits for other activities in the shoreland zone, like replacing a patio or a house, said David Madore, a spokesman for the Department of Environmental Protection, in an email. But engineers and others who work on the coast said they’re seeing more and more homeowners armor their shorelines against a rising ocean and increasingly violent storms.

“The price point has gone up, but the ability of the new homeowners to invest in it has also gone up,” said BJ Grindle, owner of Maine Coast Marine, who estimated he’s seen his call volume double in recent years. 

Shoreline protection isn’t cheap: Grindle charges $8,000 for permitting alone, and estimates that it costs between $2,000 to $3,000 per lineal foot of shoreline, depending on the project. Contractors work only in the fall and winter, when the ground is frozen, to minimize damage to the shore, and often have to barge in materials from the sea if there’s no way to get them over land. 

Projects can easily run into the tens or even hundreds of thousands of dollars, particularly if they’re on islands or out-of-the way peninsulas. Wind and weather complicate an already difficult job — Grindle, who has one barge, was stuck in Bar Harbor for six weeks this winter because the winds were too high for him to leave. The job is “grueling on a lot of levels,” said Grindle. “Long hours, very remote, and very uncomfortable — it’s brutal, it’s cold, it’s windy, it’s wet all the time.”

While many Maine coastal homeowners can bear the cost of repeatedly tinkering with a design, others who inherited property and that’s “the only thing they have,” said Walsh. So writing a check for tens of thousands of dollars for a fix that may only last a few years and will require maintenance is a hard sell.

“It’s really hard for me to say, ‘We’re going to design this for you and you’re going to spend tens of thousands of dollars on it, and I’m not sure if it’s going to last a year,’” said Walsh. 

“It’s a bit of a predicament. We’ve created this situation, and I realize people want it to be different. I understand maybe from the standpoint of (the Department) looking at a sand dune and saying, ‘this should be natural.’” He paused. “We passed the natural point a long time ago.”

Walsh’s company recently designed a living shoreline for a Freeport homeowner to stabilize the slope in front of her house. He returned to the property last month and the system they designed — engineered fabrics and plantings, which cost between $40,000 to $50,000 — was gone.

“She told me: ‘I need a solution that isn’t going to wash away.’”

 

Kate Cough covers the environment for The Maine Monitor. Reach her by email with story ideas: kate@themainemonitor.org

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Kate Cough

Kate Cough is editor of The Maine Monitor. Before that, she served as enterprise editor for the Monitor while also covering energy and the environment and writing the weekly Climate Monitor newsletter. Before joining the Monitor, Kate was a beat reporter for The Ellsworth American and digital media strategist for The Ellsworth American and Mount Desert Islander. Kate graduated with honors from Columbia University Graduate School of Journalism and Magna Cum Laude from Bryn Mawr College.
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