Flooding in Charleston, South Carolina after Hurricane Matthew in October 2016.

Flooding in Charleston, South Carolina after Hurricane Matthew in October 2016. USCG / Petty Officer 3rd Class Alexandria Preston

Fortress Charleston: Will Walling Off the City Hold Back the Waters?

Officials in Charleston, South Carolina have endorsed a $2 billion plan to wall off the historic downtown from rising seas and surging storms. It is the latest in a growing number of extravagantly expensive seawalls and barriers being proposed to defend U.S. coastal cities.

For millions of visitors each year, Charleston, South Carolina is a reminder of a bygone era, showcasing antebellum mansions, arty row houses, historic African-American churches, and sprawling views of the harbor from a Civil War-era promenade.

What those visitors don’t see is that Charleston is drowning in slow motion and soon will face an existential threat to its survival from rising seas and bigger, more powerful storms — this, even as development continues nearly unchecked.

The city is limned by its harbor and three rivers. It leaks at every bend and curve, filling streets, pooling on critical evacuation routes, disrupting business, and rushing into homes in storms. Those million-dollar antebellum mansions tucked behind the Low Battery have flooded three times since 2015, resulting in millions in damage. Homes in nearby neighborhoods, such as James Island, store sandbags under their car ports. Built atop spongy marsh and old tidal creeks filled with sawdust, they flood repeatedly, including last month when a storm pushed nearly a foot of water into some homes.

“It’s a nightmare,” says Ana Zimmerman, who moved her family to higher ground after her James Island home flooded twice — once in 2015 in a 1,000-year rainstorm and again in Hurricane Irma in 2017.

Charleston officials are preparing to rewrite the city’s master plan to deal with chronic flooding all across the 112-square-mile city and may end a controversial practice allowing developers to “fill and build” on old creek beds. In mid-April, they endorsed an even more dramatic plan by the U.S. Army Corps of Engineers to wall-off the historic downtown with an 8-mile-long seawall that would cost nearly $2 billion.

A $2-billion plan to protect historic Charleston involves building an 8-mile-long seawall, pump stations, and a barrier to stop storm waves.

A $2-billion plan to protect historic Charleston involves building an 8-mile-long seawall, pump stations, and a barrier to stop storm waves. U.S. Army Corps of Engineers

“If you even want to have the opportunity to prosper for another 350 years, even another 100 years, I believe you have got to look at the reality of doing something like this,” Mayor John Tecklenburg told the Charleston Post and Courier.

The proposed barricade is just one of a growing number of extravagantly expensive seawalls, surge gates, levees, and other barriers the nation’s engineers have proposed to defend Charleston and other U.S. coastal cities in an era of rising seas and climate-fueled floods and storms. No doubt some will be slowed by the COVID-19 economic meltdown. But for now, most are moving ahead.

  • In Miami, the Army Corps is studying a 13-foot-high flood wall along the densely developed shoreline from North Miami to Brickell. The idea is to protect 2.8 million people and over $300 billion in property in an area that often floods at high tide. Most of the estimated $8 billion price tag would be covered by federal taxpayers. The plan also includes buying or elevating hundreds of properties.
  • In Galveston, Texas, the Corps has proposed placing a massive Dutch-style surge gate in front of the Houston Ship Channel to keep a wall of water from swamping dozens of oil refineries and storage facilities. The plan — known as the Coastal Spine — includes a levee ringing the back side of Galveston Island, which was inundated in 2008 in Hurricane Ike; restored marsh along the nearby Bolivar Peninsula; and dramatically wider beaches with towering sand berms. The estimated cost has ballooned from $2 billion to $37 billion. A related proposal calls for a 27-mile levee and floodwall along the upper Texas coast, near Port Arthur and its oil facilities. That would cost about $2 billion.
  • In New Jersey, the Corps last year published a preliminary plan to protect billions of dollars of property lining the state’s bays. Tens of thousands of houses along Barnegat Bay and the back sides of several barrier islands were inundated in 2012 in Hurricane Sandy. The storm caused about $35 billion in damage statewide and led to a fourfold increase in federal flood payouts. The Corps’ plan looks at a mix of surge gates, barriers, levees, restored wetlands, and home buyouts and elevations. Cost estimates range from several billion dollars up to $15 billion.
  • In New York, the Corps proposed building a huge seawall across Lower Manhattan to block storm surge in hurricanes like Sandy, which pushed a 13-foot wall of water onto Wall Street. The cost would be enormous — somewhere between $62 billion and $119 billion, with the wall extending for five miles from Sandy Hook, New Jersey, to Breezy Point, in the city borough of Queens. Last winter, the project was quietly placed on hold after President Trump ridiculed it as “foolish” and advised New Yorkers to “get mops and buckets ready.”
The debate over these barriers is sometimes heated and points to the difficult and costly choices facing coastal communities.

The debate over these and other barriers is sometimes heated and points to the difficult and costly choices confronting taxpayers, political leaders, and coastal communities as diverse as Boston, Tampa, Norfolk, Wilmington (North Carolina), and Charleston. Even as the risks become better known, many coastal communities are continuing to grow — in some cases, dramatically. The challenges of managing that growth pit development and profits against the steady, seemingly inevitable encroachment of water — with development winning in most cases.

“Welcome to America,” says Robert S. Young, director of the Program for the Study of Developed Shorelines at Western Carolina University. “In America, we have yet to come to terms with the fact that climate change tells us there are some places where growth is no longer possible. In a way, we need to come up with a new definition of what success means beyond simple growth.”

Young contends a seawall won’t stop flooding in Charleston and may give homeowners a false sense of security. For those and other reasons, he calls it “a big wall of distraction.”

University of Miami geologist Harold R. Wanless takes an even sharper view of the Corps’ seawalls, saying they are “very arrogant and poorly thought through.”

He is especially critical of the Miami seawall, which is designed to stop hurricane storm surge, not rising sea levels. The city is built on top of porous limestone, he notes, which allows water to seep up from underneath, flooding the streets during full moons and King Tides, so-called nuisance flooding. “The wall won’t do anything to stop that,” he says.

With sea level rise accelerating, Miami is drowning in place, Wanless adds. But “Miamians seem to have this horrible concept of permanence of place, even though Miami has only been around a hundred years.”

Researchers generally agree that sea levels are likely to rise by at least 3 feet by the end of the century. But Wanless believes warming oceans, ice melt in Greenland and Antarctica, and other factors will result in two to three times those estimates — a view some other scientists share. That will amplify the risks at a time when wetter, more intense storms are causing unprecedented damage along the East and Gulf Coasts — nearly $1 trillion worth in the last four decades. Damage from hurricanes tops that caused by wildfires, earthquakes, and tornadoes combined, federal data show. Coastal storms also account for three-quarters of all payouts by the National Flood Insurance Program, which is $20 billion in debt from hurricanes and other storms over the last two decades.

A flooded street in downtown Charleston after an intense rainstorm in October 2015.

A flooded street in downtown Charleston after an intense rainstorm in October 2015. AP Photo/Chuck Burton

Risk aside, Americans keep flocking to the coast, and builders keep accommodating them. Charleston has added thousands of new houses in recent decades, city data show, including on Johns Island, a low-lying barrier about 10 miles from downtown. Part of the island belongs to Charleston. Officials have been criticized for allowing developers to fill old creek beds and build into the sides of sand dunes, creating swales and exacerbating flooding. With an elevation of only six feet in places, new houses are also exposed to storm surge.

“The city is talking about building a wall around the city while they ignore the kind of abuses going on out here on Johns Island,” says Phillip Dustan, a biology professor at the College of Charleston and a longtime resident of Johns Island. “We just continue to have this old antiquated view that developers know best, and just let them roll. Now, we have all of these people living in low-lying areas.”

Charleston’s mayor and town council are aware that they need to do more to address flooding, says Dale Morris, a researcher and co-author of a recent study of the city’s flood issues. The report was funded by the city and critical of development trends on Johns Island and other neighborhoods vulnerable to flooding. It recommended the city prevent builders from filling creek beds for new houses. Morris noted that many building permits were issued under old land use regulations that he says need to be revised. “Hopefully, they will be able to do a better job linking land use to future development when they write the new comprehensive plan in the next year,” he said.

The Charleston mayor’s office did not respond to a request for an interview.

The seawall will only protect the downtown, which accounts for just 25 percent of Charleston’s population of 136,000.

The study Morris co-authored — known as the Dutch Dialogues for incorporating many ideas from the Netherlands about living with water — included suggestions for raising roads, elevating houses, and leaving areas in parts of Charleston undeveloped to store water in future storms. The study also suggested that some form of “perimeter” defense may be needed to save the historic downtown but did not explicitly endorse a seawall.

The question is whether a wall will keep out the water. The Army Corps’ plan calls for an 8-mile-long barrier that can be elevated to 12 feet, with a series of pumps to remove water near the walls. But it is intended to stop storm surge in a hurricane, not sea level rise, and doesn’t include any of the recommendations from the Dutch Dialogues. At least some water will continue to leak from beneath the peninsula, flooding roads and neighborhoods. And the rampart will only protect downtown, which accounts for just 25 percent of Charleston’s population of 136,000, most of whom live on James Island and other neighborhoods.

“Charleston isn’t perfect,” Morris said, “but from what I can see it is far ahead of most of the other cities on the East Coast in trying to deal with flooding.”

And that points to a problem, says Ana Zimmerman, the James Island resident who is an immunologist and a vocal flood activist. If Charleston is the model, then coastal communities have a long way to go before they are truly resilient.

Zimmerman has been battling with city officials over flood issues for several years, and in 2018 documented problems on James Island in a 17-page letter to city and federal officials. She is still waiting for a response, she said. “The way I look at it, the Dutch Dialogues was a photo opportunity for the mayor,” she said. “We’re continuing with more building on a peninsula that’s sinking.”