Eroding SC beaches spark plan for new-fangled seawall

March 3, 2014 

An experimental plastic seawall that is supposed to help stop beach erosion by trapping sand.


— A walk along the seashore at the Isle of Palms reveals an experimental contraption some call the answer to South Carolina’s long-standing struggle with beach erosion.

It’s a flexible, plastic fence intended to protect hotels, dunes and seaside cottages from angry waves – but without causing the beach erosion associated with concrete or wooden seawalls.

Developed by a Charleston County resident with help from an engineering professor at The Citadel, the plastic wall idea gained enthusiastic support last week in Columbia from state lawmakers who want to allow the devices anywhere erosion is a threat to buildings.

The Senate Agriculture and Natural Resources Committee voted unanimously Thursday to allow the walls on South Carolina beaches as part of several changes to the state’s 1988 beach management law.

Not everyone is thrilled with the plan. State regulators and the S.C. Coastal Conservation League say the plastic wall system, known as a “wave dissipation device,” needs more study. One nationally renowned geologist called the device a “snake oil” gadget that is little more than a seawall that will worsen beach erosion and block public access to the shore.

But Palmetto State politicians are sky high about the invention.

“We have an opportunity here for a real breakthrough in South Carolina,” state Sen. Danny Verdin, R-Laurens, said during last week’s meeting in Columbia.

Sen. Paul Campbell, R-Berkeley, said “this new technology is really exciting; it will change what ... we can do along the coast.”

Sen. Chip Campsen, R-Charleston, said Lowcountry businessman Deron Nettles approached him last summer about the system that Nettles and Citadel professor Tim Mays had developed. Campsen later worked with the state Department of Health and Environmental Control to have a wall installed on a stretch of the Isle of Palms as an experiment, to see how it fared.

It didn’t take long to realize the system worked, said Campsen, a self-described “surfing buddy” of the lawyer representing Nettles and Mays. Campsen championed the plan to legalize the plastic walls at last week’s agriculture committee meeting.

“It’s a very innovative system; I applaud his creativity,” Campsen said, noting that Nettles “put a lot of capital at risk to try to provide a solution.”

Nettles declined to give an exact figure but said his expenditures topped $100,000.

In Columbia to pitch his idea to senators, Nettles said the device isn’t a seawall. Posts are driven into the beach and plastic slats are run between them to protect buildings and dunes. When the ocean hits the walls, the plastic slats bend and open slightly, allowing some water and sand to wash through.

That’s important because other types of oceanside walls are not flexible. Waves that hit concrete or wooden seawalls bounce off the walls, dig out the beach in front of them and wash sand away. Thus, the beach erodes more quickly.

Nettles’ system allows just enough water and sand to get through to prevent beach erosion, boosters said.

Campsen, who closely follows beach issues, said an appealing feature of the wave dissipation system is that it can be put up quickly when high seas threaten – and taken down quickly when the threat subsides. He said the walls appear to be as effective as unsightly sand bags, which take more effort to install and remove.

During loggerhead sea turtle nesting season, when a clear path between sand dunes and the ocean is needed, slats in the walls can be removed to help the rare reptiles as they crawl between the ocean and land, system backers said.

Legislation before the Senate focuses on allowing the walls as temporary methods to protect buildings during storms and high tides, in much the same way sand bags now are used. But it isn’t clear whether a wave dissipation device could stay up permanently, much like a seawall.

Wave dissipation systems apparently are not legal in South Carolina, which has a 26-year-old prohibition against new oceanfront bulkheads and seawalls. Both the Senate and the House, as well as Gov. Nikki Haley, would have to sign off on the plan before the method could be used in any way other than as an experiment, wave dissipation supporters said.

The Legislature banned new seawalls in 1988 after a series of unusually high tides washed away pools and decks in the Myrtle Beach area in 1987. The concern was that the walls had eroded Grand Strand beaches, bringing more dangerous waves closer to the buildings they were supposed to protect.

Since the 1988 beach act, the state has relied heavily on artificially widening the seashore through taxpayer-funded renourishment projects at resort beaches, many of which continue to erode. The sand eventually washes away, but temporarily holds off the effect of rising sea levels. Now, with state and federal dollars harder to get for renourishment, the seawall issue has begun to resurface. One senator last year sought to lift the state’s ban on seawalls to help a Folly Beach property owner protect his home.

So far, The Citadel’s Mays said the 6-foot-high, 88-foot-long wall at the Isle of Palms has performed well in shielding property from the ocean. Mays and Nettles said they’ve seen no erosion caused by the wall, up or down the beach, or right in front of the structure. The wall also has helped the beach build up behind it, Mays said.

Erected late last year, the wall sits in front of a condominium complex in the Wild Dunes area, a section of the Isle of Palms with a history of eroding beaches that threaten buildings.

“As of Jan. 15, we had enough evidence to go forward,” Mays said, referring to preliminary results of the wall’s effectiveness.

Despite the enthusiasm for Nettles’ plan, state regulators said they’d like to see other walls tested before giving wholesale approval to the system.

One concern by DHEC director Catherine Templeton is “locking in a particular technology,” agency lobbyist Jonathan Yarborough told lawmakers.

DHEC wants the wall’s developers “to put this particular type of structure in another location to see if there are similar effects,” Yarborough said.

Anne Peterson Hutto, a legislative specialist with the Coastal Conservation League, said “we don’t know all the potential effects” the system could have on other beach property.

Duke University coastal geologist Orrin Pilkey said he doubts more study will make a difference. If the device is blocking sand, it is interfering with the natural movement of the beach, he said. And if the device is too large, it could limit public access to the beach, he said.

“Basically, this is a seawall,” Pilkey said. “It will cause the loss of beach and it is not going to help property behind it. I just can’t believe that in this day and age this kind of device would be on the market. It ain’t gonna work. I’d stake my reputation on it.”

“I call these kinds of things snake oil devices.”

Questions also surfaced about whether trying to legalize wave dissipation systems would jeopardize a bill intended to prevent development from encroaching farther onto the beach. The wave system was attached to a bill that would prevent a state building restriction line from moving seaward after renourishment projects.

Pilkey, an author known nationally for his hard line against development on eroding beaches, said he hopes the wave dissipation system plan doesn’t slow down the building restriction bill.

He said the wave dissipation device purports to solve a problem that can’t be solved: protecting seaside buildings with walls without hurting the beach.

“If you could do all that, fantastic,” he said. “But it is absolutely not possible.”

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