How seawalls protect houses and hotels at the expense of the public beach

Uneasy about the work occurring on the beach near her home, a Hilton Head Island property owner sued her neighbors in 2019, challenging construction of a seawall they say was badly needed.

The 449-foot-long seawall was supposed to protect five homes from the rising ocean.

But Karen Wells feared that it would make erosion of the public beach worse. And in reflecting seawater away from the five properties, the wall could send a rush of water onto nearby land, including hers, Wells and her attorneys said.

"The concern was always about the potential for long-term damage – not just for us but everyone in the community,'' Wells said.

Wells' lawsuit, which was later settled and dismissed, highlights the worries many people have about seawalls on the public beach.

Seawalls, typically vertical structures that run parallel to the shore, prevent beaches from moving naturally inland as sea levels rise and storms occur. When that happens, pounding waves dig out the beach, causing much needed sand to wash into the ocean.

The dry sand beach can disappear at high tide, leaving only water for the public to slog through. The erosion associated with a seawall can create a steep drop from upland property to the beach at low tide.

In Tybee Island, Ga., just south of Hilton Head Island, people at one point had to climb down ladders to reach the beach, coastal researcher Clark Alexander said.

"Other than protecting an individual's upland property, there is no reason for a seawall,'' said Alexander, who directs the Skidaway Institute of Oceanography, a University of Georgia division in Savannah.

In addition to causing a lack of dry sand beach for people to walk on, seawalls can hurt wildlife. One of the biggest impacts is on sea turtles. The walls block turtles from nesting on parts of the seashore. That can cause them to lay eggs in places that threaten chances young turtles will hatch or survive, if they hatch.

Despite those problems, property owners battling rising seas are increasingly seeking exemptions or changes in state law allowing them to build new seawalls or rebuild old ones.

One landowner at the Isle of Palms is in a legal fight with state regulators over a new seawall on the beach. In recent years, landowners along the beaches at Debordieu, Litchfield and Garden City, all just south of Myrtle Beach, have also run afoul of state regulators over seawall and sandbag installations.

Scientists say the answer to swelling seas isn't more seawalls.

Tim Kana, who founded Coastal Science and Engineering in Columbia, said seawalls are a particular problem when beaches are not routinely renourished with extra sand.

Pumping sand on the beach widens it out and keeps the surf from hitting the walls. But renourishment projects are temporary solutions, and if follow up projects are not done, the ocean will again hit the seawall as erosion continues, Kana said.

Kana, whose company designs renourishment projects, said seawalls can be a problem for neighbors because the rushing water will run around the end of the walls, wash away adjacent dunes and threaten the neighbors' land. Large sandbags can have similar effects, he and others said.

All told, anywhere from 13 percent to 19 percent of the state's developed shoreline contains seawalls, revetments and bulkheads, depending on what sections of coast are included, studies show. Revetments are basically piles of rocks. A bulkhead is a type of seawall.

Statewide, about 17 miles of beaches in South Carolina are fortified by seawalls and similar structures, according to research Kana did in the 1980s. Kana said the findings in the report generally hold true because the state has banned new seawalls since 1988.

State data appear to verify that. The S.C. Department of Environmental Services says about 18 miles of developed coast have seawalls and other types of erosion control devices.

Most seawalls in South Carolina were built from the 1950s to early 1980s, and some were rediscovered only recently.

"Storms that have impacted the state over the past several years have uncovered some historic structures that were not previously documented,'' according to an email from the Environmental Services agency's Laura Renwick.

Seawalls in Myrtle Beach, Hilton Head Island

Seawalls are most prevalent on the Grand Strand, according to Kana's research. The area has an estimated 8.6 miles of seawalls and similar devices, such as revetments and bulkheads. The Charleston area has about 5.7 miles of seawalls and similar structures, mostly in Folly Beach, while the Hilton Head Island area has slightly more than 4 miles, according to Kana's research.

Nationally, anywhere from 12 to 30 percent of shorelines contained seawalls, bulkheads or other devices used to "armor'' upland property, or protect it from the water, according to a 2018 study by a team of researchers from universities in Georgia, Virginia and California. The walls they examined protected land in both marshes and on beaches.

The 2018 study found that, generally, seawalls and similar structures hurt the surrounding environment. Some 71 percent of the time, seawalls and structures like them were considered to have "significantly negative'' impacts, the study said.

Kana said a seawall or sandbag should be used only to temporarily protect coastal property. For the most part, seawalls should not be made permanent or they should be covered up with sand to prevent the exposure to the water, he said.

"I'm glad we have banned new seawalls, but there are occasions where an emergency sandbag or seawall structure is worth it to buy some time,'' Kana said.

Kana estimated that, today, most of the seawalls that existed when new ones were banned are buried in sand because local governments have continued to renourish beaches.

In Wells' case at Hilton Head Island, the town began renourishing the beach after her neighbors built the seawall, diminishing the threat because the extra sand is keeping waves from hitting the wall, she said.

But there could be a day when sand washes away and water will smack the seawall, she said.

"I would expect, at some point, if we have a significant enough storm event, that the seawall will be exposed,'' she said.

Rob Young, a noted coastal geologist from Western Carolina University, said it is becoming increasingly difficult to keep seawalls covered in sand through renourishment projects because they are expensive and offshore sand deposits aren't always easy to locate.

"It's hard to say what we're going to run out of first: money or sand,'' he said. "But the idea that we'll be doing nourishment everywhere 50 years from now – I don't think so.''

The bottom line is that coastal property is in jeopardy and there is no long-term solution to rising seas and more intense storms for property owners on the immediate beachfront, he said. The only long-term solution is to develop new structures farther away from the beach, experts say.

South Carolina's beach management law, criticized by some legislators as too tough on oceanfront property owners, is clear in its assessment of seawalls. The law says, not only are they bad for the beach, but they can mislead property owners into thinking their seaside homes are safe.

"The use of armoring in the form of hard erosion control devices such as seawalls, bulkheads, and rip-rap to protect erosion-threatened structures adjacent to the beach has not proven effective,'' the state's 1988 beach law says.

"These armoring devices have given a false sense of security to beachfront property owners. In reality, these hard structures, in many instances, have increased the vulnerability of beachfront property to damage from wind and waves while contributing to the deterioration and loss of the dry sand beach which is so important to the tourism industry.''