Beach erosion sets off battle at Debordieu

The beach was dry and wide when Mary Risher Osteen’s family built a house at this high-end resort 30 years ago.

Now, waves routinely smack a seawall and the ocean often covers the beach in front of the family home. Hours before high tide this week, children walked in shin-deep water because the seashore has eroded so badly.

“The water used to be way out there, and it has just moved in,” Osteen said Tuesday, pointing beyond the breakers along Debordieu’s south end. “No one would have built out into the water like this.’’

Beach erosion is a major worry for many property owners at Debordieu, an exclusive gated community of more than 1,000 homes between Pawleys Island and Georgetown. But the community’s latest plan to address the problem — up for a hearing this morning — has launched a growing storm of scientific concern.

Not more than two miles from Debordieu is North Inlet, one of the nation’s cleanest tidal estuaries and a centerpiece of the University of South Carolina’s Baruch Marine Field Laboratory. North Inlet is so unspoiled that scientists say it is vital to the study of marine life in a pollution-free environment.

Since 1969, researchers have completed more than 650 studies associated with the Baruch lab, and today are actively engaged in some 70 research projects. The area is significant enough that North Inlet is one of just 27 national estuarine research reserves in the country.

So anything done at nearby Debordieu is of note to the Baruch Foundation, a non-profit organization that owns and protects the property for research by USC, Clemson and other universities.

In this case, Debordieu wants to build three sand-trapping devices in the ocean as part of an extensive beach restoration proposal. The sand-trapping devices, known as groins, are proposed to make the new beach renourishment project last longer at Debordieu and protect seaside homes valued at millions of dollars.

But while groins trap sand and help hold the beach in place above them, areas of the beach below groins — in this case, the Baruch property— often erode at faster rates, because they are starved for sand.

That worries the Baruch Foundation and environmental groups that have joined in a legal challenge against Debordieu’s beach restoration plan.

They are expected to tell the Department of Health and Environmental Control board this morning that the unspoiled beaches at North Inlet will erode more rapidly if the three groins are built. The DHEC board must decide whether to overrule a staff decision to allow the groins.

“We believe that the damage to the beachfront property to the south of the permitted project will be substantial,’’ according to a March 13 letter to DHEC from Brett D. Moore, whose coastal engineering company is helping the Baruch Foundation.

No one knows for sure how the groins could affect the North Inlet research area.

But groins and jetties on other parts of the Palmetto State’s coast have at times had impacts on beaches below them. Much of the erosion at Folly Beach, for instance, is blamed on jetties that keep Charleston Harbor open. In this case, the Debordieu groins will extend perpendicular to the beach about 300 feet offshore on the extreme south end of Debordieu’s oceanfront.

If erosion eats away at the North Inlet beach downstream and changes sand patterns, it could affect bird habitat, disrupt nesting areas for sea turtles and threaten salt marshes, critics say.

“The proposed groins would harm the sensitive and ecologically fragile North Inlet. and have adverse impacts on the research being conducted,’’ according to a permit appeal by the S.C. Environmental Law Project.

Jim Morris, director of USC’s Baruch Institute, said losing sand at the North Inlet research area could hurt the ability of inlet salt marshes to maintain elevation as sea level rises. Sand is vital to the foundation of marshes, but without it, marshes can disappear. Salt marshes are important to the growth of baby crabs, fish and other young marine life.

Even the slightest impacts from development — in this case groins — could affect long-term research at North Inlet because the water is so clean. That’s a concern because the Baruch laboratory has gained plenty of national acclaim for its work over the years. One such project examined toxic algae in the late 1990s, when scientists across the country were trying to understand how algae were killing fish.

Overall, USC has for decades carefully monitored water quality and studied fish in the unspoiled inlet. If enough erosion occurs on North Inlet’s beach, for instance, it could cause fish to move away from certain areas that have been studied for years. In turn, the same fish would not be in those areas to compare to previous study periods.

The area on the Baruch property of most concern is a stretch of beach just below Debordieu that contains towering sand dunes and maritime forest. It extends for about two miles below the last house. At one point in the past, it was separated from Debordieu by an inlet that has since filled in naturally.

On a boat trip through North Inlet this week, USC researcher Erik Smith pointed out the dunes and dazzling white sand that ring the shoreline below Debordieu. Along the narrow strip of beach, aqua-colored water sparkled in the midday sun, as fish jumped and birds dove to gobble them up. Not far away, dolphins surfaced.

“It’s as pretty as you will see in this part of the country,’’ Smith said.

Ellison Smith, a lawyer for the Debordieu property owners, said he’s not worried about the groin project affecting North Inlet and the Baruch Foundation property. Past environmental disputes over dredging work at Debordieu haven’t hurt water quality on the Baruch property, he said.

Smith, who is not related to Erik Smith, said property owners on Debordieu’s south end need help, particularly those whose houses are behind the seawall that also protects Mary Osteen’s family beach home. About a dozen homes are on the beachfront behind the seawall, records show.

Beach erosion is nothing new in South Carolina, but it’s more significant at Debordieu’s lower end than at many other beaches. On parts of Debordieu, the erosion rate has reached about 13 feet annually in recent years. The average erosion rate for South Carolina is 1 to 3 feet per year, Ellison Smith said.

“Without the groins and renourishment, there’s no question about what will ultimately happen,’’ Ellison Smith said.” The seawall will fail. And all of the lots behind that seawall will start slumping off into the damned ocean.’’

Debordieu homeowners could drop the plan for groins and just renourish the beach, which would mollify the concerns of environmentalists. But that would force them to renourish the beach more often at greater expense, project boosters say. The groins are expected to make the beach renourishment project last eight to nine years, rather than five to six years. The project would start next year, records show.

That will help save money for property owners, some of whom are paying $72,000 apiece for the renourishment and groin project, which Ellison Smith said may cost $10 million to $12 million overall.

Osteen said the last thing anyone at Debordieu wants is to hurt the Baruch property. Many people in her community support scientific research by USC scientists and others, she said. She often takes walks down the beach from Debordieu to North Inlet.

“The research that goes on in North Inlet is excellent and wonderful and I’m all about protecting our wildlife,’’ she said Tuesday. “But I also understand there are houses here. And people enjoy this beach on a regular basis.’’