A living shoreline being constructed in the Florida Panhandle's Apalachicola Bay is protecting a critical local highway, while fostering marsh areas and oyster habitat that’s seen years of decline.
The Apalachicola Bay Living Shoreline/Franklin 98 project, sponsored by the Tallahassee-based Apalachee Regional Planning Council, is a $15.75-million project aiming to bolster the resilience of six miles of Florida Highway 98 between Eastpoint and Yent Bayou, a designated Hurricane Evacuation Route that has consistently seen damage—and required costly repairs—following storm events.
Nearshore reefs under construction will help attenuate wave energy to create a calmer environment on the landward side, create nearshore habitat for oysters and other marine species, and build intertidal marsh habitats that stabilize the shoreline by capturing sediment.
The 2,000-ft-long Phase 1 was recently completed, with two more construction phases to go to complete the total six miles of reef area. Josh Adams, environmental planning manager with the Apalachee Regional Planning Council, says the project has about one more year of construction. Officials are already looking for more potential sites in the bay.
The project includes a total of 20 acres of engineered oyster reefs and 30 acres of salt marshes through intertidal marsh construction, according to project engineer WSP.
The project won’t halt the effects of storm surge from hurricanes or other large storms, says Will Mather, environmental scientist and associate consultant with WSP’s Tallahassee office, but instead addresses the everyday, constant erosion that has slowly chipped away at the highway.
Many of the workers on the project are locals who have experience repairing the highway with seawalls and other traditional infrastructure, Mather notes.
“We want to use green infrastructure, something that grows on its own and doesn’t require a lot of maintenance,” he says. “As the oysters will live and die, they’ll adjust to sea level rise, and the same with the marsh; it’ll grow where it’s most preferable for the plant.”
It’s already having a positive effect on the highway’s resiliency, as seen with Hurricane Helene in September. “While the road didn’t fail or anything like that, a lot of sediment was ripped away from the shoulders,” Mather says. “But we did see that in the areas behind our living shoreline project sites, there was less erosion. In fact, there was accretion.”
He explains that the reef breaks up the wave energy, and then the water filters through the marsh area, which lets the sediment drop out of the water.
“[We saw] how much sediment we captured and prevented from being pulled into the bay, versus areas that were directly next door to our project sites that had the entire shoulder wrecked away,” he says.
The structures capture sediment and provide shelter for oysters, since they are placed at optimal elevation for them. At high tide, the structures will be underwater, as designed. The reefs have already seen oyster growth. That’s big news for Apalachicola Bay, where oyster populations dropped low enough for the Florida Fish and Wildlife Conservation Commission to suspend the harvesting of wild oysters in 2020. The ban will be lifted on Dec. 31, 2025.
“Hundreds of millions of oysters will be coming off of these reefs to help supplement the stuff on the coast and also the deeper water oyster reefs,” Mather says, adding that as they grow, the oysters essentially turn whatever they’re growing on into a solid structure, further enhancing wave attenuation. “They’re kind of like a natural cement as they start to grow in all the cracks and lock all the rocks together.”
Excavators are used to place the reef materials at low tide. Photo courtesy WSP
Adams, with the Apalachee Regional Planning Council, says the project began with a feasibility study in 2018 that included GIS models of roughly 30 variables. The study analyzed areas with marsh, areas without marsh, which areas were close to channels and docking areas the project needed to avoid and more, “just to get an idea that if we had the funding available, what sites would be top priorities.”
That resulted in a top-10 ranking of sites, with the highest-ranking locations of shoreline along Franklin 98.
“[Franklin 98] was an area that was extremely vulnerable because of the highway, the schools, there’s a lot of critical infrastructure right off of that 12-mile stretch,” Mather says. “So we had the data to confirm yes, this area is very vulnerable.”
A series of workshops followed, engaging the public and agencies like the Florida Fish and Wildlife Conservation Commission, researchers from Florida State University, the National Fish and Wildlife Foundation (NFWF) and other experts.
Permits for the main project took about 18 months to secure from the Army Corps of Engineers and Florida Dept. of Environmental Protection, a process delayed by about six months due to the pandemic, Adams says.
The council was able to secure funding for the project via a $7.4-million grant from the NFWF’s Emergency Coastal Resilience Fund in 2020, with money allocated by Congress and the National Oceanic and Atmospheric Agency following hurricanes Michael and Florence. Those funds were matched by around $8.3 million from the Gulf Environmental Benefit Fund, also administered by NFWF, from a total of more than $2.5 billion resulting from BP and Transocean plea agreements after the 2010 Deepwater Horizon explosion and oil spill.
“What was really great about being able to leverage those against one another, we had the ability to continue doing meetings as final designs progressed,” Adams says. “Every few months we took that to the public, asked them what they thought, maintained the steering committee, bounced ideas off them.”
WSP engineering teams spent a lot of time modeling the placement of reefs, Mather says, taking into account up to Category 3 hurricanes. Mapping via GIS and GPS had Mather out in the water with a headlamp at 2 a.m. finding seagrass beds. Their locations ultimately dictated the “amoebic” shape of the structures, as permits required a certain distance of the structures from the seagrass beds.
Early on, Adams says, the team began experimenting with materials that would comprise the near-shore, hard-bottom reefs. The team received a permit to conduct a study with different materials in place for 18 months, including both traditional materials like lime rock, oyster shells and granite and engineered materials like jute fabric-coated in Portland cement.
Currently, recycled concrete from other county projects is being used on the project, Mather says.
Placing the materials at low tide via excavator required dancing around weather, tides, traffic conditions and more, he adds, with the team accessing the site from shore as opposed to barges or other approaches from the water.
Logistics on the project included ensuring crews could maximize work windows during low tide, before 2-3 ft of water comes in with the tide. After closing the highway, materials were brought in via truck and ferried out to the reef sites via skid steers before being finally placed with excavators. An average of 70 tons per day are placed, constituting four or five reefs. Swamp mats are also used to ensure equipment doesn't sink into the soft ground.
With permitting in place and positive feedback rolling in, Mather and Adams say the crew is ready to extend the project once more funding becomes available.
