Charleston preservationists batten down the hatches to protect the city's historic resources from rising waters 

Treading water

click to enlarge flooding_magnum.jpg

Ruta Smith

History lives in the Holy City. It breathes in the centuries-old churches that canvas downtown. It stands in vibrant communities like Cainhoy. The past is part of Charleston's modern identity, thanks in no small part to tourism and historic preservation projects from downtown to the outer reaches of West Ashley.

But if history is alive in 2019, it's not immune to the problems of the modern world. Because of Charleston's location on the coast, the city is regularly reminded that sea level rise is occurring at a distressing rate. Preservationists say that consistent flooding is the biggest threat climate change presents to the city's history.

click to enlarge Kristopher King, executive director of the Preservation Society, advocates for smarter growth - RUTA SMITH
  • Ruta Smith
  • Kristopher King, executive director of the Preservation Society, advocates for smarter growth

"If you weigh the number of historically cultural resources at risk, it's pretty eye-opening," says Kristopher King, executive director of the Preservation Society of Charleston.

"In Charleston, a lot of our built environment is historic," says Erin Minnigan, the group's director of historic preservation. "[There's] something that feels really important about saving. Over these several years, seeing increased storm events, increased flooding events, the city and the preservation community recognized the need to address this for homeowners."

Just like most flooding woes in the city, there are a number of possible solutions, and some could protect the city's historic resources. But can they stack up against continued sea level rise in the long-run?

Why We Flood

Flood damage may not be apparent from the curbside view of historic structures, but high waters regularly affect the internal components of these buildings. "It usually entails damage to wiring, mechanical ductwork, HVAC systems, and interior finishes," says Winslow Hastie, Historic Charleston Foundation's president and CEO. "Repeated flooding from storm surges has horrible impacts to landscaping and plants due to the salt content of the water."

As dramatic and presumptuous as it sounds, it was only a matter of time before Charleston's location and sea level rise caught up.

"It's no wonder, looking at historic maps, why our city floods," says Minnigan. "So much of our city is built on in-filled creeks and marshes."

"There are places that were built on, and I don't care whether they were built in the 1980s or the 1880s, [but] they never should have been built on," says King, pointing to segments of downtown, West Ashley, and Johns Island as examples.

Many portions of the area that flood used to be marshland until they were filled in to make way for development, which continues today.

click to enlarge Alfred O. Halsey compiled a map in 1949 showing, among many things, that era’s high tide encroachment (in deep blue) on the Charleston peninsula - COURTESY HISTORIC CHARLESTON FOUNDATION
  • Courtesy Historic Charleston Foundation
  • Alfred O. Halsey compiled a map in 1949 showing, among many things, that era’s high tide encroachment (in deep blue) on the Charleston peninsula

"We know the areas that flood: the fill areas, the areas that aren't historic high ground, a lot on the western side of the peninsula, but there's certainly low areas," says Hastie. "Water Street is called 'Water Street' because it used to be a creek. Market Street used to be Daniel's Creek, and it floods."

"There's this famous map that we've all known about in our circles, but now it's used all the time because it shows where all the fill areas [are]," he continues. "It shows the old extent of the city with the natural marshes and all of that, and then it shows the boundaries of the current peninsula. It's pretty dramatic. I think you could argue at least a third of the peninsula, if not more, is fill."

Fortunately, Charleston's oldest structures were largely built on high ground, meaning some of them are less likely to flood. "We are lucky to live in a wonderful coastal community that has historically always flooded," says Leah Farrell, the Preservation Society's director of advocacy and public affairs. "We've understood water, we've understood where to grow. This phenomenon of 'fill and build' is newer. It's not sustainable."

Construction on filled-in areas resulted in a FEMA-granted buyout of nine homes and 32 condos that were prone to flooding in the Church Creek area of the Shadowmoss Plantation subdivision. Demolition of these West Ashley homes commenced on May 1, 2019.

Hastie believes that it will become more common if the city continues on its current track.

Flooding is a byzantine and well-trodden problem for the Holy City, and one that, at least recently, has received a large part of the local government's attention.

"We are working on many fronts to address flooding and it includes new perimeter protection, like the reinforcement in elevation of the Low Battery," says Jacob Lindsey, the city's planning, preservation, and sustainability director. "We're also working on helping individual homeowners flood proof their homes by elevating them out of flood waters. Third, we're looking at new and innovative stormwater drainage techniques."

click to enlarge One plan currently on the table is to raise the Low Battery Seawall in order to combat - the estimated 2.5 feet of sea-level rise over the coming decades - CHARLESTON CIVIC DESIGN CENTER
  • Charleston Civic Design Center
  • One plan currently on the table is to raise the Low Battery Seawall in order to combat the estimated 2.5 feet of sea-level rise over the coming decades

The City of Charleston and the Historic Charleston Foundation also teamed up to bring the Dutch Dialogues to Charleston, starting in January 2019. The Dutch Dialogues is a program designed to spotlight the Dutch methodology for managing water and flood infrastructure.

So far, the Dutch Dialogues Charleston team has spent the year collecting information, listening to resident comments, and studying four key areas of the city —Johns Island, Lockwood corridor, Vardells and Newmarket Creek drainage basin, and Church Creek basin — each representing a unique development pattern.

The final report and recommendations from the Dutch Dialogues team will be presented on Sept. 26.

Stormwater's effects on other communities have given preservationists more cause for concern.

The 2016 flash flood that struck Ellicott City, Maryland's historic district, serves as a visible warning of water's power when concentrated. Even though the town is about 10 miles from the nearest river, water built, causing devastating results to historic structures. In addition to two lives lost, "four or five" buildings were completely destroyed and 20-30 buildings had significant damage in the historic Main Street district, according to The Baltimore Sun.

Ellicott City's downtown area dates back to 1772. In May, it was announced that Howard County, where the town resides, will spend $140 million to mitigate the flooding caused by stormwater. But, the plan will only lower the amount of water coming in, not halt it.

"It's a cautionary tale for Charleston," Farrell says, believing Ellicott City is a valuable example for the Lowcountry.

click to enlarge Many downtown Charleston homeowners are choosing to elevate the structures to avoid the flood waters - RUTA SMITH
  • Ruta Smith
  • Many downtown Charleston homeowners are choosing to elevate the structures to avoid the flood waters

Staying Dry

One of the difficulties with preventing a flood from entering an historic site, and one reason why preservationists are particular about how they flood-proof, is that some permanent methods to protect a building will alter the factors that make it worth saving in the first place.

In the preservation world, there are two schools of thought when it comes to flood-proofing a historic resource: dry floodproofing (keeping the water out), and wet floodproofing (letting the water flow through without damaging).

Dry floodproofing is the most observable method, and has been a technique used by residents during most storm events. This includes traditional sandbags, inflatable barriers, and hard walls designed to halt the flow of water.

While keeping the water outside of a historic area is the most instinctive reaction, dry floodproofing requires adequate warning time to implement and frequent maintenance, leading some to suggest more innovative approaches, often through wet floodproofing.

"Wet floodproofing a structure consists of modifying the uninhabited portions (such as a crawlspace or an unfinished basement) to allow floodwaters to enter and exit," according to FEMA. Openings are put into a home that water flows through, sometimes filling a basin underneath the house. But, even this method isn't perfect.

If flood waters reach the interior of the structure, extensive cleanup will be required, periodic maintenance is sometimes necessary, and wet floodproofing does not minimize potential damage from high-velocity floods and waves.

Preservationists in Newport, R.I. are advocating for more wet flood-proofing designs to combat rising sea levels and floodwaters in their historic community.

"Architects, planners, and engineers are devising novel approaches, such as allowing water to flow through threatened structures; turning basements into cisterns; installing building-size flotation systems; or re-plumbing entire neighborhoods to direct storm water and high tides out of the way," a New York Times story on the area said on July 8.

click to enlarge RUTA SMITH
  • Ruta Smith

In Charleston, preservationists are pushing for elevating historic structures that are prone to flooding, a move that surprises even advocates.

"If you had asked me five years ago if we would support people jacking up their houses, I would have laughed," Hastie says. "Charleston's pretty conservative when it comes to preservation, and the relationship of a building to the street and to its neighbors are really important. You start jacking houses up and it disrupts that pattern and that historic character of the area. But, we have to be responsive to the changing factors that we're facing and it doesn't do a historic property any good to repeatedly flood."

FEMA describes several techniques to lift a house: For most frame, masonry veneer, and masonry houses, the foundation is separated from the rest of the structure, raised by hydraulic jacks, and held by temporary supports, while a taller foundation is installed.

click to enlarge Elevating a home more than three feet requires BAR approval and can cost as much as $400,000 - RUTA SMITH
  • Ruta Smith
  • Elevating a home more than three feet requires BAR approval and can cost as much as $400,000

It may have been unorthodox at one time, but raising historic buildings has become such a popular idea that the City of Charleston has provided guidelines for residents considering their options.

click to enlarge RUTA SMITH
  • Ruta Smith

"It's a best practices guide created with our Board of Architectural Review that shows homeowners how they can lift their buildings up, get them out of harm's way, but still preserve the historic integrity of the building, the streetscape, and the neighborhood," says Lindsey.

Residents are encouraged to consider the streetscape around them, site design, foundation design, and architectural/preservation aspects before applying. Elevating a home more than three feet requires approval from the Board of Architectural Review.

"A lot of those elevations are occurring on the lower western part of the peninsula," says Minnigan.

While it may work for historic homes, elevating structures does have limited applications, beyond the hefty price tag, which can run up to $400,000, according to King.

"Big monumental buildings like churches in the historic district need to be dry flood proofed. You can't elevate them," Lindsey states. "They have to be retrofitted or built in such a way that they keep the water out and that's a different technique than elevating."

In addition, other historic resources like graveyards and historic communities simply can't be lifted out of harm's way.

King stated that elevating buildings is a good plan for the present, but showed apprehension towards current long-term strategies.

"I think the elevated buildings is the right step for downtown," King said, "but I think there needs to be short-, mid-, and long-term discussions about what we want the city to be, what we want it to look like, how we want it to function in 50 years, because if we continue the same approach we've had for the last 40 years, the west side of the peninsula is going to be in big trouble."

The Year 2219

Is Charleston sustainable? Sure, it could be considered a melodramatic question, but it's also one that coastal communities should ask themselves.

According to the National Oceanic and Atmospheric Administration, the sea level outside of Charleston has increased by 3.26 millimeters per year with a margin of error of 0.19 millimeters, since 1901. This equates to a 1.07-foot increase over the last 100 years.

In 2018, the Proceedings of the National Academy of Sciences reported that sea level rise is not continuing at a steady rate; it's accelerating around the world.

"Just look at the projections," Hastie responded when asked if Charleston could be sustained another 200 years. "It's real hard for me to say. I'm from here, I grew up here, I've made it my life's work to protect this place and make sure it grows responsibly."

"But, I think we're going to be looking at a retreat after a certain period of time," he adds. "I mean, that's just where we're headed and that's a global situation."

click to enlarge Historic Charleston Foundation president and CEO Winslow Hastie was integral to the City of Charleston’s Dutch Dialogues - RUTA SMITH
  • Ruta Smith
  • Historic Charleston Foundation president and CEO Winslow Hastie was integral to the City of Charleston’s Dutch Dialogues

The Preservation Society took a pragmatic, but optimistic view on the same question. "We need to fortify, we need to harden the edge, we also need to soften the edge by creating natural infrastructure, we need to be able to get the water out, we have to protect the houses, we have to build better," King describes. "It gets overwhelming, but these are all things that are very, very doable.

Of course, this comes with the caveat from both parties that, even if sustained, the city will not look the same.

"One of the things that we've heard from talking with other communities, particularly international folks, you also are going to have to be prepared to abandon certain areas," King says.

No one interviewed would say what communities would be abandoned first, but the City of Charleston's Sea Level Rise Viewer clearly shows the southwestern and northeastern parts of the peninsula turning blue if sea levels increase by another three feet.

All of this comes before considering storm surge from hurricanes and flooding on a rainy day.

So where does that leave many of Charleston's historic resources? On a peninsula surrounded by rising waters.

It's a dire, but not hopeless, situation. Smarter development practices, like restoring natural landscapes and using growth as a mechanism to mitigate flooding, can have powerful effects, according to the Preservation Society. And the city's Dutch Dialogues will reveal their recommendations to lessen water problems around Charleston in the coming months.

But everything needs to happen at once, and it needs to happen now. The ocean's not getting any smaller, after all.


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