Climate, costs could bring more beach structures like temporary walls
Seas keep rising. So does the cost of beach renourishment. More and more, Lowcountry communities will be forced to choose between buying more time or buying more sand.
And that means that structures like removable walls might soon be as commonplace as the ubiquitous umbrellas on the beaches.
Seas rose more than a foot from 1926 to 2006, according to the National Oceanic and Atmospheric Administration. Experts expect them to rise at least another foot in the next 50 years, and measurements now indicate that the rate is accelerating. Each inch pushes storm surge and flood tides higher, exacerbating severe erosion already taking place across the developed, vulnerable, low-lying barrier islands of the South Carolina coast.
Over the next 20 years, more sea walls of some sort will be called for, more renourishment demanded because of storms, flood tides and erosion. Every spot protected might well mean the one next door would erode more quickly.
"A lot of people don't want to recognize the level is rising, but it is. Are the coasts at risk? Of course they are," said Richard Berg, Illinois State Geological Survey chief scientist.
Meanwhile, the beach communities around Charleston already sink millions of dollars per year into renourishment projects, while property owners fight or defy state rules denying walls to protect their homes.
The 2008 Wild Dunes renourishment cost $10 million. A Folly Beach project now underway is estimated to cost nearly $30 million.
ISLE OF PALMS - The pipe wall standing between the Seascape Villas condominiums and the crashing waves doesn't look like the future; it looks like Legos.
But it just might become part of the new face of Lowcountry beaches.
The 88-foot long "wave dissipation system" is a study project erected by carpenter Deron Nettles under the auspices of The Citadel. The idea is to break up the storm waves that cause the worst beach erosion, but allow water and fine sand to pass back and forth between the pipes, simulating the flow on an unobstructed beach.
Seascape is the second in a line of condominium complexes on the volatile, eroding east tip of Isle of Palms, where Dewees Inlet rakes and re-rakes the beachscape. Before a 2008 renourishment, erosion undermined condominiums there, tore apart the signature 18th hole on the oceanfront golf course and led to a fiasco of washed-away sandbags.
Today, the golf hole and the Ocean Club condos between the hole and Seascape again are packed behind walls of sand bags, while erosion managers wait for an offshore sandbar to attach to the beach. The wall is what Seascape has going for it.
The beauty of this assembly of reinforced plastic and composite parts is that, like Legos, it can be built to size, installed along the dunes as needed - when a hurricane, a Nor'easter, or even just an astronomical high tide is on the way. Then it can be removed and the beach left as beach.
Unlike other types sea walls, or even sand bags, the pipe wall doesn't stop the sand flow, so ideally it won't exacerbate erosion on either end. That's just one of the things the study is trying to determine.
There are just a few little problems. First, the wall as it stands technically isn't legal. State law prohibits sea walls in most cases. The wall is allowed until Jan. 15 as a study, and only because The Citadel is involved.
And the wall is just the latest in a long line of "trip wall" ideas to protect beaches from erosion, a list that includes stuff like concrete discs and artificial seaweed, some of which just haven't worked very well.
"Any kind of semi-permeable shore protection has a limited use at best. At the end of the day, what you really need is more sand on the beach," said Tim Kana, of Coastal Science and Engineering, who is overseeing management of the Wild Dunes erosion.
In other words, Nettles, 44, has some convincing to do - and so far he has done that.
This idea was born two years ago, literally as a line in the sand in front of his parents' beachfront Sullivan's Island home. Nettles surveyed the erosion there, sat down and began sketching a fix, as carpenters are wont to do.
He took his idea to Tim Mays, a professor at The Citadel, who specializes in coastal engineering. Mays has seen this sort of stuff before, but this one caught his eye.
"The potential is amazing," Mays said. It's a solution that balances ecological, property and aesthetic concerns, while "the huge amount of wave energy coming in, it kills on the spot."
Mays isn't the only convert. Richard Berg, Illinois State Geological Survey chief scientist, studies erosion and protection along Lake Michigan. He also has a home at Wild Dunes. He came across the wall recently while walking on the beach and began watching it perform day to day.
"I've always been a little reluctant of 'magic pills' to solve long-term issues," Berg said, and it's too soon in the study to draw any conclusions. "But he might be on to something."
The state will be tougher to sway, but it's budging.
"As currently built and configured, the wave dissipation system could not be permitted," said Dan Burger, coastal service division director for S.C. Department of Health and Environmental Control. But DHEC will review the research, he said.
Nettles realizes that the system isn't a total fix, he said, but it is a tool to protect properties and maybe delay the need for expensive renourishments.
He has gone at this full bore. He formed SI Systems and has patents pending for the gear. He is paying The Citadel for Mays to oversee the research.
"They say 90 percent of people who come with (patent) ideas don't follow through on them," he said. "I don't want to be one of them. I'm going to give it a shot."
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Tim Mays, associate professor of civil engineering at The Citadel, explains Tuesday why the wave dissipation system being studied on the beach at Wild Dunes’ Seascape Villas is better than a solid wall at slowing erosion.×
The new wave dissipation system placed on the beach in front of the Seascape Villas on Isle of Palms allows water to flow through it, thus dissipating erosive forces in front of the structure, according to designer Deron Nettles.×
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