Proposed storm wall has Army Corps weighing cultural, aesthetic impacts of rising seas 

Building a Wall

click to enlarge Charleston's flooding often inhibits mobility

US Dept. of Agriculture

Charleston's flooding often inhibits mobility

The U.S. Army Corps of Engineers has released the overview of its Charleston Peninsula Study, giving an early look at what they believe can stop flooding in the city's culturally rich downtown area. The plans were met with skepticism from some, partially because of the proposed storm surge wall's placement leaving significant areas, such as Magnolia Cemetery, unprotected. Experts from various environmental studies have also shown some apprehension toward the plan, but stay hopeful that modifications can be made over the next 12 months.

The Army Corps' three-year study, approved in 2018, is in its preliminary phases and will be complete next year. The study overview released last week provides insight into the full plan. In its current iteration, the Army Corps calls for a storm surge wall that runs parallel to the peninsula's shore, storm surge gates that will close during low tide, and wave attenuators off the coast to reflect inbound waves back into the harbor.

As noted by other media outlets, the storm surge wall will not protect the South Carolina Aquarium or the site of the future International African American Museum. Structures in that area "are elevated higher than elevation 12 [feet]," says Wes Wilson, an Army Corps project controls program manager. "Our storm surge wall cannot reduce the risk of damages of places that are higher than our current elevated wall."

The Army Corps website notes that areas outside of the wall are on higher elevations. Some topographic maps will dispute this claim, but the city's sea level rise viewer seems to suggest that those particular areas will mostly be spared as the ocean rises another three inches. By the year 2100, sea level is likely to rise 12 inches above what it was a century earlier, climate change experts say.

The storm surge wall would protect against a storm like Hurricane Hugo, says Scott Harris, a College of Charleston geology professor who specializes in the coastal plain. But things get tricky when sea level rise is taken into account. "It's what's happening in 50 years, what's happening in 100 years," he says. "I hate to say, but the economy is really driven on a 5-30 year [plan]. We have to get out of that."

click to enlarge CITY PAPER/U.S. ARMY CORPS OF ENGINEERS
  • City Paper/U.S. Army Corps of Engineers

While the plan tries to shield the peninsula from the next 50 years of flooding, Harris suggests that people should look beyond that. "We could be looking at a foot and a half or three feet. That becomes real. That becomes real ugly," he says. The Army Corps of Engineers' plan says the storm wall can be made taller in the future.

In the past, some flooding experts have shown worry about flood barriers, believing they will push water to other areas that do not usually flood. Harris is skeptical that the Corps' plan will cause this, claiming that it wouldn't make a noticeable difference. "That volume of water is basically irrelevant," he says. "If we take this entire peninsula project, and we look at the volume of water that's there, how the storm surge comes in, the impacts are going to be nil to minimal."

The Army Corps' plan is not yet complete or approved. Over the course of the next year, the group will examine potential adverse effects to communities surrounding the peninsula. If analysis indicates heavy negative impacts, planning will begin for appropriate mitigation to counteract the effects.

Deborah Bidwell, a College of Charleston biology professor and biomimicry expert, encourages careful analysis of how the storm wall will interact with storm surges. "It could definitely reflect waves in other areas and they'll need to be careful about studying the impacts of wave energy coming off of that barrier," she says.

Historic Charleston Foundation, one of the organizations to spearhead flooding and resiliency study the Dutch Dialogues, hasn't made an official stance on the Corps' project. But, the group's president Winslow Hastie believes the city might have to accept the plan to survive increased flooding events. Although he says there are potentially negative impacts, Hastie trusts it's worthy of the city's attention.

"We shouldn't start out from a negative place approaching this," he says. "We've got to really think hard about how this feature will intersect with our historic district and the internationally significant historic resources in downtown Charleston."

The Charleston Peninsula Study is federally funded, utilizing $3 million from Emergency Supplement Funding to develop long-term solutions to storm problems. The Army Corps of Engineers is asking for community input through June 19. Ultimately, the plan will need congressional approval to be built. Bidwell calls for an inclusive comment period, allowing people of all socio-economic backgrounds and races to voice their opinions. "They need to invite all stakeholders into the conversation," she says.

According to Wilson, there will be another opportunity for public engagement in early 2021. "We want to ensure that we get proper feedback from the public," he says. "We'll have a better idea of what kind of non-structural measures we'll be doing."

Several of Harris' critiques of the plan speak to the potential impact on the city's aesthetics and access to water. "You need the humaneness of the architectural people and the people who live in town," he says, advocating for a merge between the current plan and the recommendations found in the Dutch Dialogues. "I imagine we'll do that, but these are the things that are missing."

Wilson says visuals will be taken into account as the project moves forward. "We're not at the design phase at the moment," he says. "We are going to work closely with the City of Charleston to determine those aesthetic features, as well as the recreational opportunities."

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