Folly Beach using marsh mapping in 2023 sea level rise adaptation plan

FOLLY BEACH, S.C. (WCSC) - The City of Folly Beach is using new marshfront data to update its 2023 Sea Level Rise Adaptation Plan.

The barrier island floods more and more every year due to sea level rise. That’s why the city hired a local coastal geologist to map the marsh and see how it plays into the landscape.

Elko Coastal Consulting President Nicole Elko and those working with her spent the summer of 2022 surveying and mapping what’s called the critical line of the marsh. They took satellite measurements every 20 feet to the elevation of where the marsh ends and where the upland ecosystem begins.

“In our survey of the critical line, we found that the critical line sits at an elevation of about eight feet relative to our tidal datum. So, if you’re out here on Folly, we talk about six-foot tides, we talk about eight-foot tides-- that’s normally your king tide. It’s that one that’s starting to come up over the marsh, perhaps cause some flooding on the island,” Elko explains.

This information can be used to map sea level rise and understand how the landscape will change in coming years. For the city, they will use the information to adjust irrigation, assess the seawall and plan infrastructure to grow with the changing environment.

“The guidance tells us that events that we’re seeing now are going to happen 10 times more often by 2050. So, in less than 30 years. We are going to be seeing these inundating king tides which are happening once a month now happen 10 times a month. So it’s going to have a significant impact on all coastal property as well as the way the city is managing the infrastructure here on the island,” Elko says.

For people who live on the island, like Kristen Phillips Kappel and her daughter Drayton, the natural wonders are what drew them to Folly.

“I like when we walk down the beach and find like different kinds of animals like one time we found this really weird thing and we looked it up. It was called like, an onion...a sea onion,” Drayton says.

The mother daughter duo believe cataloguing, protecting, and growing with nature is essential to Folly’s community.

“It’s absolutely enhanced our life to be able to have this beauty of nature around us and kind of live in synchronicity with it. We take a lot of walks and we probably have our best talks when we’re walking,” Kristen says.

Elko says while the State and Army Corps of Engineers along with hired coastal geologists have surveyed the beaches and replenished that land for year, there hasn’t been the same focus on the marsh. Yet, the marsh also has a significant impact across barrier islands.

“The marshes are the nursery grounds for all of the fish that end up in the ocean as well as oysters, crabs, etc. It’s very important resource for us to maintain with sea level rise with climate change over the next five to 10 years. We’re already seeing some more routine flooding on the island. So, the ocean is kind of crossing that critical line boundary more often than it has in the past,” Elko says.

Elko will present her findings to Folly Beach City Council at Tuesday’s regular meeting. Her advice to the city is to collect new data every three years on the marsh.

You can read her report in the agenda on pages 3-18.

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