Towards a More Perfect Union: Integrating Hard and Soft Armoring Techniques in the Panhandle

Coastal communities throughout the Apalachee Region are all too familiar with chronic erosion along the shorelines. Summer and winter storms bring high winds and raise water levels; chronic erosion is a daily occurrence with the ebb and flow of the tide. Year after year, Franklin County’s shoreline experiences these conditions, causing portions of coastal Highway 98 to suffer.

Highway 98 is the main artery and the only evacuation route for many residents of the surrounding  communities, tying Franklin County together, covering Apalachicola, Eastpoint, Carrabelle, and St Teresa. It acts as the only thoroughfare for some residents. For decades, various traditional approaches to coastal protection including hard armoring techniques ranging from wooden and concrete seawalls and bulkheads, to rip rap and roadway foundations of articulated concrete have been implemented. Until recently, these efforts have been standard approaches to mitigate against coastal erosion that often preempt existing and potential habitat from forming and migrating – seawalls and riprap effectively draw a line in the sand for coastal geomorphological and ecological functions. Looking to implement a different approach, the Apalachee Regional Planning Council (ARPC) partnered with WSP USA to explore a method involving design and implementation of a living shoreline project, one that sought to breach the gap between hard armoring and “soft” solutions such as installing vegetation along shorelines. This is the basis for Franklin-98.

Franklin-98 is a nature-based solution that involves establishing a nearshore reef and marsh ecosystem, bolstering the general productivity and health of the nearshore ecosystem while capturing, or attenuating wave energy in Apalachee Bay before it has a chance to reach shore. The nearshore hardbottom reefs, constructed out of limestone sourced from Florida, have been observed providing home to this past year’s oyster set. Once a primary driver of the local economy that accounted for 90% of the total Florida oyster yield, the fishery has since collapsed, with laws put in place to prevent wild harvest through 2026. It is important to note that the F-98 project is not primarily an oyster restoration project, and separate from FWCs much larger restoration efforts, though the project has seen oyster recruitment on the reefs. Additionally, the project is located in a “no harvest” zone.

The installation of nearshore reefs helps to attenuate wave energy in a novel way, unique from other linear formations that direct wave energy on the sides, potentially leading to scouring on the sides of the engineered structure. Taking inspiration from natural oyster formation, our reefs are irregularly shaped, and the length and depth of the structures slows the waves before reaching shore. The effects on energy reduction are profound and are visible, even on an average day. The reefs will not prevent all erosion or provide the same type of wave attenuation as seawalls and riprap. They are much lower in elevation, protruding only a few feet out of the water, and totally submerged on the highest tides.

The reefs are installed in shallow water, less than six feet. Materials are positioned in the water using excavators from barges in deeper areas, and directly from land when working in and around the intertidal zone, carefully, as to not disturb any of the submerged aquatic vegetation (SAV) that may be present in the area, and to ensure proper layout of the reefs. The SAV are field verified and mapped ahead of placement to avoid any accidents. Some of the workers from the project are oystermen, leveraging their experience to help construct the reefs. Construction work is being performed by North Florida Construction, a local contractor operating in Franklin County.

Spartina alterniflora, or smooth chordgrass, is the dominant species that is being used to establish our fringing marsh. With the reefs in place, the wave climate becomes favorable for marsh species. The saltmarsh helps to trap suspended sediments in the water column and aids in growing the shoreline. The GulfCorps of the Forgotten Coast, an AmeriCorps program based out of Franklin County, is the contractor responsible for the planting portion of the restoration process. GulfCorps crews partner with federal, state, county and municipal agencies as well as local nonprofits to implement restoration and conservation projects throughout the Florida Panhandle. The GulfCorps team has been busy harvesting, transporting, and propagating the marsh grass. The grass comes from a Duke Energy donor site in Crystal River.

The combination of the marsh and reefs will benefit the local ecology through providing enhanced habitat that has been preempted by seawall in many locations along the project area. The enhancements will also help to offset erosion and catch sediment, increasing shoreline resiliency by providing physical enhancements that can lower wave energy before they make landfall. Project design considerations included twenty-seven public outreach events, as well as data collection and analysis methodology. Franklin-98 Living Shoreline has been designed to withstand at least Category 3 wave energy and has performed well to-date since being initially installed in fall of 2023. Sea level rise was also taken into consideration when designing the marsh and reefs; both are anticipated to “grow” with the projected amount of sea level rise in our project area.

The project is already showing promising signs of early success, withstanding Hurricane Helene, that made landfall about 40 miles away. Helene peaked as a Category 4 storm and brought with it a high storm surge. The surge would leave a wrack line close to the roadway, well above our project area, which would have been under several feet of water. As the waters receded, the project was likely able to help settle the sediments that came with the storm and even accrete sediments in some places. Additional monitoring of data is needed to quantify the project’s resiliency impacts.