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Is pumping more sand onto NC beaches causing deadly currents?

Is beach nourishment making the NC coast more dangerous?

North Carolina’s preferred way to fight coastal erosion might be leading to greater risk of rip-current drownings and shorebreak injuries. A group of scientists think the possibility deserves much more serious investigation.
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North Carolina’s preferred way to fight coastal erosion might be leading to greater risk of rip-current drownings and shorebreak injuries. A group of scientists think the possibility deserves much more serious investigation.

Every four years, Wrightsville Beach is born again.

By dredge and bulldozer, eroded patches are covered with sand. Skinny parts are made wide. By the end of a beach nourishment project, emergency vehicles can pass on the dry sand without trouble, even at high tide.

“I guess we’ve all come to expect it, not for just tourism, but also for protection of property and public safety,” said Wrightsville Beach Mayor Bill Blair.

But a growing number of scientists and coastal engineers worry that there’s a serious downside: Unnaturally altered beaches could pose an elevated risk of injury to the very tourists that sand replenishment was meant to attract.

They are particularly concerned about spinal injuries due to waves breaking hard on steeper, rebuilt beaches and drownings from rip currents.

So far this summer, 10 people have drowned in rip currents off the North Carolina coast, more than the average in recent years, according to data kept by the National Weather Service. Four of those drownings took place at recently nourished beaches.

Data from the United States Lifesaving Association show sharp jumps in rip-current rescues the summer after some North Carolina nourishment projects, including four at Wrightsville Beach, according to a review by The News & Observer.

But without taking into account a whole bevy of other factors, including precipitation, storm swell and wave height, there’s no way to prove a meaningful connection.

“The problem with that is you have a conflation of the hazard with the people,” said Greg Dusek, a senior scientist at the National Oceanic and Atmospheric Administration, commonly known as NOAA. For example, “if the water’s too cold, then people aren’t going in, then it looks like you have no hazard,” he said.

However, Dusek, a leader in rip-current research, is still convinced that the anecdotal information available about the potential risks to beachgoers from nourishment warrants scientific examination. “I think it’s totally a valid research question,” he said.

Beach nourishment has been going on since the 1920s.

So why hasn’t science already answered the question?

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Beach erosion near a line of ocean-front houses in Southern Shores, N.C.. Dare County

‘No correlation’

It’s notoriously difficult to measure rip currents — strong flows of water that start close to the beach and move into deeper water, typically associated with a hole in an offshore sandbar. Sometimes rip currents show up day after day. Other times they quickly disappear.

Political incentives have also worked against scientists. Beach nourishment has emerged as a kind of holy grail of coastal erosion control, preferred over “hard stabilization” measures such as erecting sea walls and “strategic retreat,” which involves moving or demolishing buildings too close to the water. So research funding has been scarce.

Up until recently, scientists were focused on understanding rip currents in general — how they flow and the conditions surrounding them. So the study of rip currents as a public safety hazard is young. The first efforts to predict them date only to the 1990s.

Using cameras to gather data could be a breakthrough. The images show where waves are breaking, which tells scientists where the sandbar is, and averaging a series of images can make rip currents visible.

Orrin Pilkey, perhaps North Carolina’s most famed beach expert, agrees that investigating the possible link between beach nourishment and rip currents is “a heck of a good idea.”

“It’s not just a rumor that nourished beaches may cause drowning,” said Pilkey, professor emeritus of geology at Duke University, founder of the Program for the Study of Developed Shorelines at Western Carolina University and a prolific author. His books include “The Corps and the Shore,” a 1989 review of the science, engineering and politics of beach nourishment.

Pilkey thinks the U.S. Army Corps of Engineers should pay for research on whether nourishment boosts public safety hazards. “They fund the majority of beach nourishment,” he said. “They should know about this.”

The Corps, however, isn’t convinced the research is needed.

“We’ve been doing this for more than 30 years, and there’s no correlation,” said Lisa Parker, spokeswoman for the Wilmington District. Parker said she could not provide evidence that there is no correlation because the Corps hasn’t been studying the question.

‘Money is tight’

To B. Chris Brewster, a U.S. Lifesaving Association official who has heard plentiful accounts from lifeguards linking beach nourishment and safety risks, the Corps’ stance is predictable.

“The Army Corps of Engineers is to a pretty significant extent in the business of beach renourishment,” he said. “The bottom line is if you’re the one making the sausages, you’re not necessarily interested in a huge amount of study of what’s inside of them.”

The Corps’ shore protection budget is tens of millions of dollars a year. Scientists say a study would cost far less, but no specific estimates were available.

The attorney for the Corps district that includes North Carolina, Justin McCorkle, said he didn’t think anyone had raised the issue in the state. “We wouldn’t have looked into it unless somebody had alerted us that it was a problem,” he said.

U.S. Rep. Walter Jones, a Republican who has represented Eastern North Carolina since 1995, said he wasn’t aware of the issue either.

“I’ve been to many, many meetings with local officials on the coast and the Army Corps, and this is the first time I’ve ever heard of the thought that beach nourishment could be a problem with rip tides or currents,” he said.

Jones followed up with an Army Corps scientist, who told Jones that he hadn’t seen any research on the subject and that the issue wasn’t being discussed among his peers.

After that conversation, Jones told The News & Observer that he thought scientists working in academia should take the lead. “Money is very, very tight for the Corps,” Jones said. “The Corps is not prepared to move on this study.”

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Bulldozers move sand as part of a beach nourishment project in Southern Shores, N.C.. Dare County

Scientists split

A group of Florida scientists led by John Fletemeyer has been trying to get the Corps’ attention and, ideally, a slice of the agency’s research budget.

Fletemeyer is longtime lifeguard and researcher who founded Florida’s Aquatic Law and Safety Institute. He said he was recently named president of the International Drowning Prevention Coalition and plans to make investigating the influence of beach nourishment on public safety a priority.

In a letter to the editor in January’s edition of the Journal of Coastal Research, Fletemeyer and three colleagues laid out their case. They cited legal arguments and statistical evidence from Maryland, New Jersey and Florida.

Fletemeyer’s co-authors include Brian Haus, an ocean sciences professor at the University of Miami who is an expert in nearshore waves and currents; and John Hearin, a NASA contractor and surfer with a doctorate degree in ocean engineering.

“The idea that the character of the beach would alter the nearshore currents is not at all controversial,” Haus said. “It should not be a surprise to anyone. The question is whether it does it in a significant way.”

Other coastal scientists are skeptical that the need has been proven. Spencer Rogers, a coastal construction and erosion specialist at North Carolina Sea Grant, is among them.

“The beach shape is going to be different, and that’s going to affect rip currents,” he said. But he doubts that difference is necessarily worse.

Stephen Leatherman, director of the Laboratory for Coastal Research at Florida International University, also has doubts.

He said that the Florida researchers’ paper didn’t adequately establish a physical relationship between rip currents and beach nourishment. The tie between shorebreak injuries and nourishment, however, Leatherman buys.

“The sand tends to be coarser in almost every case,” said Leatherman, a Charlotte native who grew up visiting the Outer Banks. “The coarser the material, the steeper the beach. That’s a well-founded principle. It’s been proven over and over. I would expect nourished beaches to have more shorebreaks.”

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An aerial view of Southern Shores on the Outer Banks of North Carolina. Dare County

Bigger threats?

Other scientists think the question simply isn’t pressing enough. Sea level rise is a far bigger coastal problem.

“The beach must move with sea level — but the houses and roads all act as a fixed bulkhead preventing the beach and shoreface from moving — resulting in the narrowing and steepening of the beach and shoreface — which means that more wave energy comes ashore on steep, narrow beaches and increases the resulting currents,” Stanley Riggs, a coastal and marine geologist at East Carolina University, wrote in an email.

“It is like rearranging the chairs on the Titanic. There’s a much bigger problem here that needs to be dealt with.”

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But for Bill Blair, the mayor of Wrightsville Beach, that metaphorical Titanic is his home.

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Bill Blair, mayor of Wrightsville Beach

He spent the bulk of four years collecting approvals and securing funding for the town’s last nourishment project, which wrapped up in March. The final bill — $11 million, split between the federal, state and local governments, Blair said — didn’t seem too high when he looked at what could be lost.

The project reinforced about a mile of beach. But to locals, it meant more than that: the future of their community, their homes and businesses.

Blair is already at work on the logistics of the next project, scheduled four years from now.

Brosseau 919-829-4627; @carlibrosseau
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