A living shoreline being built in the Florida Panhandle’s Apalachicola Bay is protecting a critical local road while boosting wetlands and oyster habitat that have seen years of decline.
The Apalachicola Bay Living Shoreline/Franklin 98 Projectsponsored by the Tallahassee-based Apalachee Regional Planning Council, is a $15.75 million project aimed at strengthening six miles of Florida Highway 98 between Eastpoint and Yent Bayou , a designated hurricane evacuation route that has been consistently damaged and required costly. repairs: after storms.
The nearshore reefs under construction will help attenuate wave energy to create a calmer landward environment, create nearshore habitats for oysters and other marine species, and build stabilizing intertidal marsh habitats the coastline capturing sediments.
The 2,000-foot-long Phase 1 was recently completed, with two more construction phases to complete the six total miles of reef area. Josh Adams, environmental planning manager for the Apalachee Regional Planning Council, says the project is about a year away from construction. Officials are already looking at more potential sites in the bay.
The project includes a total of 20 hectares of engineered oyster reefs and 30 hectares of salt marshes through intertidal marsh construction, according to project engineer WSP.
The project won’t stop the effects of storm surge from hurricanes or other large storms, says Will Mather, an environmental scientist and associate consultant at WSP’s Tallahassee office, but instead addresses the daily, ongoing erosion that has washed away slowly on the freeway.
Many of the project workers are locals who have experience repairing the highway with levees 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 will adapt to rising sea levels, and the same goes for the marsh; it will grow where it is most preferable for the plant.”
It is already having a positive effect on highway resilience, as seen with Hurricane Helene in September. “Even though the road didn’t fail or anything like that, a lot of sediment was ripped off the shoulders,” Mather says. “But we did see that in the areas behind our shoreline project sites, there was less erosion. In fact, there was accretion.”
He explains that the reef breaks up the energy of the waves, and then the water seeps through the marsh area, which drops the sediments from the water.
“[We saw] how much sediment we captured and prevented from being washed into the bay, compared to the areas that were directly adjacent to our project sites that had the entire shoulder destroyed,” he says.
The structures capture sediment and provide refuge for the oysters, as they are placed at an optimal height for them. At high tide, the structures will be underwater, as designed. The reefs have already seen oysters grow. That’s big news for Apalachicola Bay, where oyster populations dropped enough that the Florida Fish and Wildlife Conservation Commission suspended wild oyster harvesting in 2020. The ban s will rise on December 31, 2025.
“Hundreds of millions of oysters will come out of these reefs to help supplement things on the coast and deeper water oyster reefs as well,” says Mather, adding that as they grow, the oysters become essentially what they grow in. a solid structure, further improving wave attenuation. “They are like a natural cement in that they start growing in all the cracks and seal all the rocks together.”
Excavators are used to place reef materials at low tide. Photo courtesy WSP
Adams, with Apalachee Regional Planning Council, says the project began with a feasibility study in 2018 that included GIS models of approximately 30 variables. The study looked at areas with marshland, areas without marshland, which areas were close to canals and coupling areas that the project had to avoid and more, “just to get an idea that if we had the funding available, which places would be the main priorities.”
This resulted in a ranking of places in the top 10, with the highest coastal locations along Franklin 98.
“[Franklin 98] it was an area that was extremely vulnerable because of the freeway, the schools, there’s a lot of critical infrastructure right next to that 12-mile stretch,” says Mather. “So we had the data to confirm that yes, that area is very vulnerable.”
A series of workshops followed, involving the public and agencies such as the Florida Fish and Wildlife Conservation Commission, Florida State University researchers, the National Fish and Wildlife Foundation (NFWF) and other experts.
Adams says permits for the main project took about 18 months to obtain from the Army Corps of Engineers and the Florida Department of Environmental Protection, a process that was delayed by about six months due to the pandemic
The council was able to secure funding for the project through a $7.4 million grant from the NFWF Emergency Coastal Resilience Fund in 2020, with money appropriated by Congress and the National Oceanic and Atmospheric Agency after Hurricanes Michael and Florence. These funds were matched by about $8.3 million from the Gulf Environmental Benefit Fund, also administered by NFWF, out of a total of more than $2.5 billion resulting from the BP and Transocean settlement agreements following the explosion and the 2010 Deepwater Horizon oil spill.
“What was really great about being able to leverage each other, we had the ability to continue to have meetings as the final designs progressed,” says Adams. “Every few months we took this to the public, asked them what they thought, kept the steering committee, bounced ideas off them.”
WSP engineering teams spent a lot of time modeling reef placement, Mather says, with Category 3 hurricanes in mind. Mapping using GIS and GPS got Mather on the water with a lighthouse at 2 in the morning, finding sea grass. Ultimately, their locations dictated the “amoebic” shape of the structures, as permits required a certain distance from the structures on the seagrass beds.
At first, Adams says, the team began experimenting with materials comprising nearshore and hard-bottom reefs. The team received permission to carry out a study with different materials over 18 months, including traditional materials such as limestone, oyster shells and granite, and engineered materials such as jute coated with Portland cement.
Currently, recycled concrete from other county projects is used in the project, Mather says.
Placing the materials at low tide by excavator required dancing around weather, tides, traffic conditions and more, he adds, with the team accessing the site from shore rather than barges or other approaches from the water.
Project logistics included making sure crews could maximize work windows during low tide, before 2-3 feet of water at high tide. After the highway was closed, the materials were trucked in and transported to the reef sites by mini-carts before finally being placed by excavators. An average of 70 tons are placed daily, which constitute four or five reefs. Bog mats are also used to ensure that the equipment does not sink into the soft ground.
With permits in place and positive feedback, Mather and Adams say the crew is ready to expand the project once more funding becomes available.
