Living shorelines shield habitats, homes
by Sydney Cromwell
Along Alabama’s coast, hardworking — but often overlooked — habitats are created where land and water meet.
Coastal marshes, seagrasses and reefs are home to species that support the state’s fishing and tourism industries. They reduce erosion and filter sediment and pollution from the water. And, research is increasingly showing that these ecosystems are one of the best defenses against storm damage and flooding, even more so than traditional bulkheads or seawalls.
Where these coastal habitats have been destroyed or damaged by development, “living shoreline” projects can enhance or completely recreate natural shore conditions.
Groups like the Nature Conservancy and the Mississippi-Alabama Sea Grant Consortium (MASGC) are trying to increase the number of living shorelines on properties along the Gulf Coast, for both their environmental and protective benefits.
Similar projects have also been funded as part of the 2012 RESTORE Act, which provided funding to Alabama for economic and environmental restoration after the Deepwater Horizon oil spill in 2010. The U.S. Army Corps of Engineers has even encouraged natural infrastructure design for the last ten years through its Engineering with Nature initiative.
Eric Sparks, the Sea Grant Consortium’s assistant director for outreach and coastal ecology specialist, said the hard part isn’t convincing people of the benefits of a living shoreline for their properties. It’s whether they even hear about living shorelines in the first place.
ALABAMA’S ‘HARDENED’ SHORES
Wherever there is moving wind or water, gradual erosion is happening. The shorelines of Alabama’s coast, lakes and rivers are in a constant state of long-term change.
Sparks said those slow shifts in sand and soil are inevitable, and can even be beneficial. He pointed to Dauphin Island, which has had peninsulas appear and disappear due to shoreline changes.
“Erosion is a natural process. A lot of the coast wouldn’t be here if it wasn’t for erosion from Birmingham,” which is carried down rivers and deposited in marshlands along the coast, Sparks said.
However, this gradual rate of erosion is amplified by development, dredging and the loss of coastal plants that reduce wave energy and hold soil in place. Hurricanes and severe storms also cause drastic shoreline changes, and these storms are becoming more intense due to climate change.
These factors have led to millions of dollars in property damage and loss due to erosion, as well as the disappearance of coastal marshes and intertidal habitats.
Bulkheads, seawalls, and similar artificial structures have been the typical remedy for erosion and property protection for many years to block waves from crashing in, especially during storms, and to block soil from flowing out.
A 2012 Geographical Survey of Alabama mapping project showed that 223 miles, or about 27%, of Alabama’s coastline was “hardened” or “armored” with bulkheads, sea walls, jetties and other structures. The highest rates of armored shorelines were in Bayou St. John (62%), Bayou La Batre (58.4%) and Arnica Bay (56%). Mobile Bay’s shoreline was about 38.6% hardened at the time of the study.
“You can’t fault anybody for this. That was just the way that people felt like they needed to protect their property from eroding away,” Sparks said.
Waterfront residents in Mobile Bay also perceive vertical structures like bulkheads as the most effective and durable form of shoreline protection, according to a research survey published in 2014. Those two factors, along with cost, were the top criteria for homeowners in choosing how to protect their properties.
However, Sparks said bulkheads aren’t as protective as people think. Every time a wave hits a bulkhead, its energy doesn’t disappear; the water is thrust both up into the air and down into the sea floor. That downward energy scours away soil and plant life, and it can weaken the bulkhead’s foundation.
“It actually erodes more in that water body than it would be if it had a higher proportion [of natural shorelines],” Sparks said, and it can lead to the entire loss of tidal habitats.
During hurricanes or other storms, the structures people expect to protect them can actually do more harm. These walls don’t do enough to slow down wave energy during a storm, particularly once the waves exceed the height of the bulkhead. If the bulkhead fails, it can send a huge rush of floodwaters onto coastal properties.
A 2014 survey after Hurricane Irene hit North Carolina found that 76% of bulkheads on the Outer Banks had been damaged during the storm, but marshes and natural shorelines had no damage due to erosion and plant life had recovered within a year.
Bulkheads can also cause problems as water recedes after a hurricane or heavy rain, Sparks said. The same solid structure that stops waves coming in also prevents water from flowing back out once it’s past the bulkhead.
“That water kind of piles up behind the bulkhead,” Sparks said. He has seen trapped water create more flooding, sinkholes and damaged bulkheads that were only braced for water flow from one direction.
Another North Carolina study in 2017 found that 97% of property owners with bulkheads had ever had “costs associated with property damage from hurricanes,” compared to 75% of property owners with some form of natural shoreline. Also, 61% of bulkhead owners reported yearly maintenance costs, while only 25% of natural shoreline owners reported the same.
RECREATING MOTHER NATURE
Where manmade structures fail, the marshes, reefs and other habitats native to the Gulf Coast have already adapted to survive in the face of wind and waves.
Coastal plants and offshore coral and oyster reefs all play a role in slowing waves down and reducing their energy. The gradual slope of a natural shoreline also causes waves to break without scouring soil, unlike the hard vertical barrier of a bulkhead.
“They just kind of go with the flow when the storms roll in. They hold everything together without taking too much of a beating, and then after the storm they’re still standing,” said Nigel Temple, who created the coastal restoration company Alabama Living Shorelines in 2019.
A study presented at the 2014 Conference on Coastal Engineering found that replenishing beaches and restoring wetlands, oyster reefs, and barrier islands in the Gulf Coast would have positive return on investment in protecting properties from storm damage. In particular, it predicted that $2 billion of wetland restoration could prevent an estimated $18.2 billion in property losses by 2030.
Sparks said MASGC has been monitoring its completed living shoreline projects during this year’s hurricane season, through a storm assessment project with the National Oceanic and Atmospheric Administration (NOAA).
“Not a single one of those shorelines had damage to them,” he said.
Aside from their significant property protections, marshes and intertidal habitats boost local fishery and tourism industries by supporting oyster, shrimp, crab and fish populations, said Judy Haner, the Nature Conservancy’s marine and freshwater programs director for Alabama. Many Gulf fish species grow up in marshes and seagrasses, which provide protection from larger predators.
“The little critters that live on the reefs are the things that feed the crabs,” she said. “… They’re the unsung heroes of the reef.”
These ecosystems also filter sediment and pollutants out of the water and trap carbon.
“It’s an extremely valuable piece of habitat that improves water quality a lot,” Sparks said.
The term “living shoreline” encompasses many different techniques, Sparks said. It can be as simple as covering a shoreline in native plant species, or a property may need its shoreline rebuilt, stabilized and protected through breakwaters made of stone, oyster reefs or concrete.
While concrete is not a natural material, Sparks said it can be used to shield the newly created living shoreline from damage by boat wakes or higher wave energy.
“The marsh wasn’t built to withstand a lot of that in certain areas,” he said.
Concrete can also be used to create artificial reefs or “oyster castles,” encouraging aquatic species to colonize the structures. The Gulf used to have expansive oyster reefs, Sparks said, but they have been impacted by water quality and harvesting.
Living shorelines are also more flexible than bulkheads, Sparks said, so they can continue to function even as natural erosion shifts the shoreline or as sea levels rise.
“You’ve got something that’s sustainable,” he said.
While the benefits of living shorelines have been known for years, Haner said it has been a learning process to find the most effective ways to create them. The Nature Conservancy started out with small, experimental shoreline and reef projects to see which techniques protected the coastline and encouraged fish and oyster populations. They’ve been able to share that knowledge with other groups working on coastal resilience around the world.
“We want the money and the research to build on that knowledge and not make the same mistakes over again like a hamster wheel,” she said.
One such learning experience, for instance, was finding out that bagged oyster shells, while commonly used as breakwaters, can’t stand up to high wave energy and will break down. Now, Haner said, they only use bagged shells in low-energy areas or when protected by stone or concrete structures.
Haner said they also learned that dredging sediment to add to newly created marshes will give them “a head start” to develop much more quickly.
The Nature Conservancy of Alabama has created living shorelines for about six miles of coastline so far, plus they have worked with partner groups for another seven miles, Haner said. The nonprofit also uses grant funds to continue monitoring these sites to see how they hold up several years after completion.
Aligning coastal restoration with the needs and goals of residents is also critical to the effectiveness of living shoreline creation.
The Nature Conservancy’s recent Lightning Point project in Bayou La Batre, Haner said, was a success story in marrying living shoreline techniques with community feedback. The project was a partnership between the Nature Conservancy, the city of Bayou La Batre, Mobile County, the state Department of Conservation and Natural Resources and the National Fish and Wildlife Foundation.
“We see people out fishing on the reefs every time they go out [to monitor Lightning Point], which we love,” Haner said.
Along with creating 40 acres of native coastal habitats and 1.5 miles of breakwaters, the project also included two jetties, so boats could continue to use the channel, as well as walking paths, a gazebo, and a lookout point for residents.
“That will link the environment with communities and economies. That is the sweet spot,” Haner said.
ONE PROPERTY AT A TIME
Haner said the majority of Alabama’s coastline is privately owned, so small projects by individual homeowners are key to creating a cumulative difference in shoreline protection and habitats.
MASGC holds homeowner workshops and does individual consultations to encourage exactly that.
While there are some properties where a living shoreline isn’t feasible — mainly due to high wave energy, steep elevation or the house being too close to the water — Sparks said many properties they visit can support some form of living shoreline.
“The ideal scenario is to catch someone when they’ve purchased a lot,” he said, so they can consider a living shoreline before a bulkhead has been installed.
The homeowner workshops are usually focused on one section of the coast at a time. The hardest part is getting residents to attend, Sparks said.
When property owners see the benefits of living shorelines to their own homes and the local environment, Sparks said they’re usually interested. But, they don’t always know how to take the next step, particularly in finding a contractor.
“Ninety-five percent of them will only tell you that you can put a bulkhead in there because that’s all they know how to do,” Sparks said.
The MASGC also holds contractor workshops in response to this gap, walking builders through the permitting and installation process. Sparks said the Sea Grant Consortium created a contractor certification course in Mississippi in February 2020, and they’re considering the same program for Alabama. Contractors who get the certification would maintain it as long as they complete at least one living shoreline project each year.
Temple, who worked with Sparks and attended homeowner workshops while a graduate student at Mississippi State University, did part of his dissertation work on stakeholder and community engagement for projects like living shorelines. The feedback from homeowners about the lack of contractors led him to create Alabama Living Shorelines.
Temple said he wanted to use his previous construction experience and keep project costs low to get more homeowner participation. He has created living shorelines on properties along Dog River, Fish River and Ono Island.
“As long as they’re doing that over doing a bulkhead, that’s my ultimate goal,” said Temple, who now works for WSP consulting firm and is currently constructing an oyster reef and marsh in Apalachicola Bay, Florida.
Living shorelines can cost many thousands to install, depending on shore conditions and the amount of wave protection needed. However, they are generally less expensive than installation of bulkheads and seawalls.
Along with the contractor “bottleneck,” Haner said the installation expenses are another barrier that needs to be removed. She said cities should consider cost-sharing programs for private living shoreline projects “because it’s a benefit to the greater good of the economy to not have shorelines washing away.”
The U.S. Army Corps of Engineers’ current regulations on living and armored shorelines, adopted in 2011, say that the permit for bulkheads and other hardened shoreline protection will only be approved “where it is demonstrated to the satisfaction of the Corps that there are no feasible non-structural alternatives available including, but not limited to, preservation and restoration of wetlands, submerged grassbeds, shoreline restoration and/or nourishment.”
Temple said he has seen that regulation used more frequently in recent years. He believes “minds and hearts are changing” along the Gulf Coast about the value of natural shores over hardened infrastructure.
“I think more and more people are becoming open to the idea of living shorelines. Actually, I would say more and more people are generally in favor of doing living shorelines,” he said.
Little Lagoon in Gulf Shores is an example of a community that has seen the value of embracing natural infrastructure, including living shorelines.
Dennis Hatfield, the president of the Little Lagoon Preservation Society, has lived on the north shore of Little Lagoon for 20-plus years and first visited the community, where his grandmother also lived, in 1957.
“I learned to fish and I caught my first fish in Little Lagoon,” he said.
The portion of Little Lagoon in the Bon Secour National Wildlife Refuge is “basically pristine,” Hatfield said, but the majority of the lagoon is developed.
“The edge habitat has been hardened or destroyed,” he said.
Still an avid fisherman, Hatfield said the lagoon’s populations of shrimp, crabs, flounder, speckled trout and other species have declined due to habitat loss. Without plants to pull nutrients out of the water, Hatfield said algae blooms have fed on those nutrients and caused hypoxia, or oxygen depletion, in the lagoon.
The Preservation Society was originally created due to residents’ unhappiness over state maintenance of a tidal inlet into the lagoon, which was creating problems with water circulation and pollution. Since then, Hatfield said the group has expanded its goals to encompass other preservation efforts.
“We have really focused on trying to reach out and educate people on actions which hurt the lagoon, and how we can remediate some of the problems that have been identified in the lagoon,” he said.
Hatfield, whose career background is in coastal sedimentary geology, said he has been familiar with the benefits of coastal habitats and the damage of hardened shorelines since he moved to Little Lagoon. But when he heard about the Sea Grant Consortium’s living shoreline work in 2017, he reached out to Sparks to give a presentation to the Preservation Society.
“It just made sense that we should push living shorelines,” he said.
Hatfield said the community response was good, and he “received quite a few phone calls from people that want to do living shoreline restoration.” About a dozen homeowners have expressed interest in a living shoreline project on their property, he said.
Sparks said MASGC also did a planting project last summer in the southwestern area of Little Lagoon, and another one is planned with the U.S. Fish and Wildlife Service this year.
Aside from living shorelines, Hatfield said some Little Lagoon residents have oyster gardens to filter and improve water quality of the bay. The oysters are not rated for consumption, but Hatfield said the mollusks are moved to Mobile Bay once they reach adulthood, in order to supplement depleted oyster colonies in the bay.
Hatfield said he didn’t initially expect residents to be enthused about oyster gardening, especially since they couldn’t put the results of their work on the dining table.
“Boy, was I wrong. The people that live in the lagoon recognize the importance of filter feeders like oysters to keep the environment healthy,” he said.
With the help of the city of Gulf Shores, Little Lagoon has been awarded a grant of nearly $6 million from the Alabama Gulf Recovery Council. That grant includes funding for about 1,000 feet of living shorelines; support for shellfish, seagrass and wetland restoration; improvements to the lagoon’s canals; conversion of septic systems to sanitary sewers; and ecological research and monitoring.
Hatfield said he hopes to see the first grant-funded living shoreline project, at Mo’s Landing, get started this summer. Large-scale oyster gardening, as part of the grant’s shellfish restoration funds, probably won’t start until 2022, he said.
“We’re hoping within a couple years to be growing millions of oysters in the lagoon,” he said.
Hatfield hopes those initial living shoreline projects will generate momentum.
“We’d like to convert it all [from hardened to natural shoreline], really. That’s probably not practical. I think if we had 20 or 30 projects, we’d make a dent in the hardened shorelines in the lagoon,” he said.
The Mississippi-Alabama Sea Grant Consortium website has resources
for contractors and homeowners about living shorelines,
including permitting regulations for Alabama, Florida and Mississippi.