To keep floodwaters out, Charleston is designing a sea wall

CHARLESTON, S.C. — For Belvin Olasov, growing up in the Low Country bred an inherent connection to water. Daily life has meant soaking in the good, while preparing for the bad.

“It’s a part of life that when it rains, sometimes not even that heavily, you now have an obstacle course to get around downtown, and if you fail, you lose your car,” he said.

According to Norman Levine with the Low Country Hazards Center, the issue is only worsening. In the past 100 years, Charleston’s seen the ocean rise 13 inches around the peninsula. By 2050, Levine said that’s likely to rise another foot, bringing high tide and storm surges one foot closer to life and property as well.

“At some point, a number of these properties will actually become inundated,” he said. “A third of all properties have ten feet or less or elevation.”

A dramatic proposal

In response to the threat, the US Army Corps of Engineers embarked on the Charleston Peninsula Coastal Storm Risk Management Study in 2018 and ultimately, they came up a recommended plan to build a 12-foot storm surge wall around most of the peninsula. The height is based on the devastation Hurricane Hugo caused with its 12-foot surge.

At this point, the project is still in its early stages. Wes Wilson, the project manager, said the Corps is gathering public input before coming up with a final design, but the recommendation includes a physical barrier between the water and all the low-lying portions of the peninsula as well as a series of pump stations. Preliminary estimates have the cost of the project around $1.3B.

“You look at the costs you’re going to save versus the cost it’s going to take to implement the project, the federal government has a significant interest in investing in the city,” Wilson said.

USACE plans to have the final design approved by 2026 and construction complete by 2032.

More than a wall

Understandably, the idea of a concrete storm wall around the beautiful, historic city of Charleston has prompted more than a few concerns. That’s why Dale Morris, the city’s chief resiliency officer, said a giant concrete structure cutting the city off from its water is out of the question. He said the point is to make the top of water-facing barrier 12ft above sea level, but that doesn’t necessarily mean the wall itself is 12 feet tall.

“People say, ‘a sea wall.’ We already have a beautiful sea wall at the bottom of the peninsula it’s called the low battery,” he said.

The low battery is a raised concrete structure that runs along the peninsula’s southern coast, but it’s also a walking path, a fishing pier and a place where locals and tourists alike gather to take in the sights of the water.

“It’s beautiful,” he said. “It’s multifunctional. That is what we would like this project to be around the peninsula.”

Keith Bowers, an environmental architect with Biohabitats, proposed another possibility. With his Imagine the Wall vision, he sees green infrastructure like habitat restoration and native grasses and breakwaters playing a big role alongside “gray infrastructure” like a battery wall.

“We want to have both views and access to the water, that’s what Charleston is all about,” he said. “If you had a wall, there’s a way to make a wall more conducive for a habitat.”

Not only would green infrastructure help limit the environmental impact to Charleston’s marshes, but Bowers believes it would be much more attractive to those who live and visit the shoreline. Given the importance of that shoreline to the city’s tourism industry, he believes it would be a worthwhile investment even if green infrastructure would raise the cost of the project.

“A lot of the living infrastructure that I’m talking about is looked at more as an add on or a co-benefit and that’s not necessarily calculated in the core part of the project,” he said.

Wilson said nature-based solutions are part of the plan so far, but the design needs to put the city’s safety and responsible spending first.

“Right now we’re assuming oyster castles in front of the wall that can basically act as essentially a wave attenuator to knock down the water before it hits the wall,” he said. “Engineering with nature and these nature-based solution offer a limited risk reduction to coastal storm surge. You can’t plant just 5000 palm trees along the perimeter and expect to stop storm surge.”

Who is left unprotected?

So far, the recommended plan is limited to the peninsula, but most of Charleston’s population lives across the Ashley River or further north in the “neck” communities and they’re not immune to flooding issues either.

“James Island is seeing a lot of flooding,” Olasov said. “A lot of our beaches are experiencing erosion.”

Wilson said it’s the number one concern he’s heard so far.

“More than half of public comments are worried about impacts to surrounding communities,” he said.

Wilson said most of those communities were not included in the peninsula study because the average elevation is higher than 12ft., and therefore storm surge and tidal flooding are less of a concern. In fact, he said there are breaks in the wall plan in places where the peninsula itself is above 12ft.

Additionally, he said studies showed adding the wall around the peninsula did not significantly push the water elsewhere due to size of wall against the sheer volume of water in the system.

“There would be little to no impacts,” he said. “Less than half an inch in a few areas.”

A future for our coasts

Charleston is not the only community looking at sea wall. Norfolk, New York and Houston are all considering their own version of a sea wall to fight the growing threat of sea level rise and climate change.

Wilson said engineers across the coast are in near constant discussion about the challenges they’re facing, what seems to be working and what isn’t but ultimately, he hopes Charleston can be a leader.

“We want people to come to us in 25 years and say, ‘Charleston, how did you do that?’”

For Olasov, calling Charleston home means facing the reality that the city will look different in just a few decades. He said it’s why he helped found Charleston’s Climate Coalition, to focus on what can be saved and how.

“We have to both simultaneously be resilient, accounting for the climate crisis and we have to be mitigating our emissions because if we don’t show leadership, we in one of the most vulnerable areas, who will?” he said.

At the end of the day, he said he wouldn’t live here if he didn’t believe Charleston had a future.

“It’s going to take a lot of effort,” Olasov said. “But I think that there’s a path forward where we treasure what’s unique about this place and account for the climate crisis.”

(WATCH BELOW: Charleston is sinking while the sea is rising)

Charleston is sinking while the sea is rising

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