How long can we continue to live on the coast? Depends on how much we want to spend and the amount of damage we want to cause.
By MEREDITH HAAS/ecoRI News contributor
Rhode Island is the second-most densely populated state, and its 420 miles of coastline are crowded with homes and businesses, residents and tourists. The increasing rate of erosion and sea-level rise, and the effects of coastal storms and flooding, are making the state’s coastal landscape ever smaller.
For those who think that engineering solutions will hold back the sea, Robert Fairbanks, a Rhode Island-based engineer who designs and builds hard structures to protect coastal properties, has some bad news.
“Everything is temporary,” he said. Fairbanks explained that when built correctly, barriers such as seawalls, revetments or even dunes can protect an area for an extended period of time, but not indefinitely. “It’s always an educational process explaining to a homeowner who just spent a million dollars and now thinks they’re completely protected forever. I explain to them, that’s not the way Mother Nature works.”
While hurricanes and storms such as Sandy can move sand from one place to another — Sandy alone stripped some 1,600 tons of sand away from Narragansett Town Beach and dumped about 18,000 tons onto Atlantic Avenue in Westerly — ultimately, the state is losing land over time. Despite seawall construction, beach renourishment and other measures, Rhode Island’s coastline has lost nearly 300 feet of beach in just 50 years.
This has been felt most acutely along the more exposed southern shoreline in communities from Point Judith to Westerly. Matunuck, Misquamicut and South Kingstown Town Beach have lost about 400 feet of beach combined in the past 40 years.
Narragansett’s seawall — a mile-long, steel sheet-pile seawall capped with concrete — has protected downtown Narragansett since 1933, and Newport’s Cliff Walk has endured since the end of the 19th century. Though they have weathered many storms, they were both damaged heavily by Sandy, and required millions of dollars in repairs.
Efforts are underway to restore these existing structures and others, as well as to rebuild beaches, an undertaking funded in part by the $61.4 million Rhode Island received from federal disaster relief programs to help the state recover from Sandy’s October 2012 visit. And many residents and businesses are demanding the right to build new seawalls despite strict permitting regulations that largely prohibit them in many areas.
These efforts illustrate the challenges in educating people about the risks of coastal living. Dan Goulet, engineer at the Coastal Resources Management Council (CRMC), the state agency responsible for protecting coastal resources, likened the issue to the failed bank bailouts in 2008, and said that coastal communities need long-term solutions that will require a different way of thinking for how people live on the coast instead of continually investing in infrastructure that doesn’t work.
“It’s risky to live on the coast and people don’t get it,” he said, talking about the many oceanfront properties owned by seasonal residents. “They come in the summer and it’s wonderful, but they don’t see when the ocean is lapping at their property.”
Rhode Island is one of the few states with a near-ban on construction of new hard shoreline protection structures despite the strong push to build. With the exception of pre-exisiting structures, this ban is primarily along Rhode Island’s southern shore in waters classified by CRMC as a Type 1, which abut natural, undisturbed shorelines. The south shore is also exposed to high wave energy, flooding and erosion.
CRMC officials say that new construction is banned for all Type 1 waters to protect natural-habitat sand because such structures interfere with the natural transportation of sediment and accelerate erosion. Pre-existing structures can be maintained but aren’t permitted to expand.
“We’re very concerned about sediment supply and have a limited supply on the south coast,” said Grover Fugate, CRMC’s executive director. “Seawalls block the supply, and that has downstream impacts on beaches. You can have a wall or a beach, but you can’t have both.”
Relentless wave energy
Seawalls are vertical structures made of concrete or timber, and are driven into the ground to deflect oncoming waves. This deflected wave force, however, has to go somewhere and is generally pushed back out. This accelerates erosion in front of the wall, or to the sides, causing scouring to the outside edges and damaging adjacent properties, and ultimately eroding behind the wall and rendering it useless. Revetments are engineered rock walls, but they follow the natural slope of the beach to break up wave energy and minimize erosion impacts. However, they can still pose scouring problems, and any beach in front of them will be eroded away.
This is the case in Matunuck, where a 200-foot-long steel sheet-pile seawall was approved to protect a portion of Matunuck Beach Road. This proposed structure would be an exception, to protect public health and safety, since the road is the only access to 250 homes, and protects the water supply for 1,600 homes. The total estimated cost of this project is $1.38 million, which would be funded by the state Department of Transportation.
“I’m working with South Kingstown to protect Matunuck Beach Road, because that area has eroded right to the edge of the road,” Fairbanks said. “We’ve (designed) to limit erosion at the wall by not only using a steel sheet-pile structure buried about eight feet, but also burying stone up against it so if we do lose the sand on top, the stone will be exposed. This will help stop the erosion so it won’t continue to dig the hole deeper and deeper. When the storm is over you can go back in and replace the sand, to recreate the area.”
There was opposition to the town’s original plan, which called for the wall to extend the length of the entire road. Janet Freedman, coastal geologist at CRMC, said construction will not go past the existing revetment at the Matunuck Trailer Association property on Matunuck Beach Road so as not to compromise local businesses and homes beyond. This construction, however, comes at the expense of keeping a beach in favor of protecting the road.
Not only can seawalls accelerate erosion, they can also harm the structures they are intended to protect when they aren’t built adequately to withstand wave forces and instead create harmful debris. The Andrea Hotel, a landmark in Misquamicut for nearly a century, which ultimately had to be torn down and rebuilt because of flooding damage, also suffered structural damage from seawall debris during Sandy.
“The stones were not the correct size and were like flying torpedoes,” said Michelle Carnevale, Rhode Island Sea Grant and Coastal Resources Center extension specialist, who is working with Fugate on the Rhode Island Shoreline Change Special Area Management Plan (Beach SAMP) — a management plan being developed to help coastal communities and homeowners adapt to sea-level rise, flooding and erosion.
She noted that part of the problem was that the wall was under-designed because it predated CRMC regulations. The damage that was done during Sandy to the Andrea Hotel shows that an undersize seawall can do as much, or more damage, as no seawall at all, Fugate said.
Fairbanks believes there’s a stigma against seawalls, and other hard structures, as a result of poor siting and construction.
“This is where seawalls have gotten a black eye,” he said. “People have gone in places and built things with out taking into account what effect their structure was going to have on the adjacent property.”
Fairbanks said that when built correctly, hard structures can be effective. Each structure must be designed and built to withstand the wave energy expected at its location. Structures need to withstand up to tens of thousands of pounds of force from a breaking wave during a storm. Many such structures are sloped with an uneven surface designed to reduce wave-energy impact.
“I have to understand how big the waves are during storms in order to be able to know what type of structure to use, and what it should look like height, width, material, slope,” said Fairbanks, explaining that he designs for the so-called 100-year storm, or the storm with a 1 percent chance of happening in any given year, utilizing floodplain maps and studies as recommended by the Army Corps of Engineers.
The larger the waves anticipated at a given site, the more expensive the structure. “A 27 percent increase in wave height doubles the amount of force, and that’s all cost,” Fairbanks said.
Even designing seawalls to withstand a 100-year storm may not provide the protection the name implies. First, new climate research suggests that such storms may now have a 5 percent or 10 percent chance of happening in any given year. Second, the coastal zone, subject to wave action, is determined on federal floodplain maps according to a set of variables that, for Rhode Island, don’t adequately represent true flooding risk, according to Fairbanks, Fugate, and Freedman. Part of the problem is that these new maps fail to incorporate flood marks from storms such as Sandy.
“We know they’re not accurate because we know we’ve flooded more than what they have mapped. There’s physical evidence,” Freedman said. “We know the Sandy waves were higher than the max wave they modeled for this area.”
The new maps, according to Jessica Stimson, floodplain mapping coordinator for the Rhode Island Emergency Management Agency, incorporate the past 20 years of data. Work on the maps began in 2009, and was completed prior to Sandy.
Still, she said that after Sandy, federal contractors did survey the coastline and felt the data collected didn’t indicate a need to re-delineate the maps.
Fairbanks said he doesn’t trust the maps, and that their accuracy, or lack of it, has huge implications for the effectiveness of engineered structures if they aren’t built to withstand actual conditions. Freedman said this could also hurt homeowners who believe they are outside the flood zone and yet may find their properties flooded during a major storm.
Even when an adequate seawall, or other structure is built, the initial construction expenses are only the beginning — maintenance accounts for a huge part of the overall cost, Fairbanks said. Structures will need repairs from the normal wear and tear of the ocean, as well as damages from storms, and dunes will need to be restored and replanted. Many state beaches have maintenance funds incorporated into their budgets, and dole out hundreds of thousands of dollars each year, but not all homeowners have the resources to maintain private shoreline protection over time.
Old timber and stone groins first installed in Buttonwoods, Warwick, in 1962, for example, weren’t properly maintained and ultimately accelerated erosion in the area, according to Fairbanks.
Public access can't be denied
The potential damages to the shoreline aren’t the only reason CRMC places strict regulations on construction of new hard structures. Those structures can also block public access to the shoreline, which begins at the high-tide mark.
“One thing about shoreline structures is that you lose public access,” Freedman said. “As that beach moves, you protect your house, but the public loses that right of access to the shore, and why should we?”
Property that’s been eroded can’t be reclaimed and there is no compensation for homeowners. This means as the water rises, it’s taking what used to be private land and turning it into public trust shoreline.
“The dry is becoming wet, and public property is becoming bigger, encroaching on private property,” said Susan Farady, former director of the Marine Affairs Institute at Roger Williams University. “The big issue here is private versus public rights.”
Farady said the dilemma about building structures involves how to weigh the right to protect private property against the public trust to access resources, and also determining who is responsible for the damages incurred to the surrounding properties resulting from a structure. This is one of the many issues the Beach SAMP will address.
“We base our management and property interests on a set of conditions that we’ve assumed are going to be relatively stable, which we know is clearly not the case,” Farady said. “Water is going to do what water is going to do. The issue isn’t the ocean. It’s our responses and abilities to manage our own actions.”
Current management of coastal resources inRhode Island is framed around balancing all interests along the coast but not at the expense of public access.
“We try to take emotion out of it and be pragmatic to balance it for everybody because you’ve got fishermen, people that just want to walk down the beach, the health of the beach itself, and nobody likes to be told to let (their homes) fall in the ocean. That’s tough,” CRMC’s Goulet said.
Many residents in Matunuck are indeed struggling with their limited options, and have petitioned for the shoreline there to be reclassified as manmade in order to allow hard structures. They also have requested that the existing stone revetment be extended, or that the approved seawall be moved seaward to protect waterfront properties. Although these requests have been denied in order to preserve the coastal environment and public access to the shoreline, there are still options remaining, including soft solutions such as planting vegetation and/or non-permanent structures, and installing coir logs that are biodegradable erosion-prevention logs made from coconut fiber to aid in the stabilization and revegetation of hillsides, banks and shorelines prone to erosion.
These methods, however, may not always be effective in such exposed areas, Fairbanks said.
“There’s a general thought that we can go to soft solutions,” he said, claiming that in high-energy areas like Matunuck the beach isn’t wide enough to disperse the energy coming from the ocean. “We just don’t have that kind of width here.”
For coastal headlands in Misquamicut and Matunuck, CRMC has approved non-permanent experimental erosion control measures, such as marine mattresses that are rock-filled containers intended to slow or abate erosion without the damages inflicted by seawalls.
While some of these methods have been effective in other areas around the country, it’s unclear how they will fare on Rhode Island’s coast.
As the results of the experimental measures being undertaken in Matunuck and Miquamicut become more apparent, more options for property owners may become viable. Nevertheless, both coastal engineers and resource managers say that all measures are just buying time.
The question is, how much?
This story was originally published in the spring/summer 2014 edition of the Rhode Island Sea Grant publication 41º North.