Stories of devastation in South Nags Head and Rodanthe or the breach Hurricane Isabel created on Hatteras Island can oversimplify the issues of Outer Banks erosion, according to Billy Edge, a civil engineering professor and head of the Sustainable Engineering in Coastal Environments program for the UNC Coastal Studies Institute.

“The Banks are not all eroding,” Edge said.

The real issue is the dynamic nature of the shoreline, which grows or shrinks changeably.

“[The shoreline] changes daily, monthly, seasonally, with storms and in the long-term,” Margery Overton, a civil engineering professor, said.

Erin Lineberger, a sophomore in natural resources, said trying to establish a community in such an environment is what makes the shoreline change such an issue.

“The erosion of the Banks is not our fault,” Lineberger said. “The problem is that we built on that. Building on the Banks is not sustainable.”

In a high energy system like the Outer Banks, waves refract, reflect and diffract, and currents remove the sand. Alongshore currents carry it down the coast, while cross-shore currents take it back out to sea. That sand is not being replaced.

“If any [sand] goes down towards Miami, there are no rivers bringing sand back to the Banks anymore,” Edge said.

This sand exodus is accelerated and made more dangerous by the large storms which often sweep through the area, taking ocean-side sand landward, according to Edge.

Under these conditions, legislators and locals have worked to find coping mechanisms.

“North Carolina is one of a handful that bans the use of shoreline stabilization structures,” Overton said. “That limits your options on how to deal with shoreline erosion.”

Shoreline stabilization structures encompass an array of constructions. These include off-shore breakwaters, where rocks off the coast force waves to break and expend their energy before reaching the shore. Revetments — energy-absorbing structures on the slope of the shore — are also an option, as well as perched sills — a structure underneath the water line which acts almost like a shelf, holding the sand up at a higher and less eroded level.

Other beaches have used jetties and terminal groins with some success; these structures work like speed bumps for the sand. Each extends perpendicular to the beach and collects sand before the alongshore current rushes it off to Florida. But the sand budget is still a problem.

“If we put something in, we affect sand on either side,” Edge said, meaning jetties amass sand on one side but allow it to erode on the other side disproportionally.

This solution could hurt tourism as much as erosion, according to Lineberger.

“We lose that commercial aspect through erosion,” Lineberger said, and added that terminal groins can be eyesores. “People aren’t going to like that. It won’t preserve the natural integrity, and it’s not as original or nice a place to go. That’s what people love about the Banks — they’re kind of wild.”

“The only things people are allowed to use are sandbags,” Edge said. “If a house is threatened but not 50 percent damaged, you are allowed to put sandbags out until the beach recovers.”

The ban on structures came about as part of the defense of the environmental integrity of the Banks, something that means a lot to inhabitants and vacationers.

“Our banks are unique in their geomorphology,” Overton said. At the time of the ban, she described the legislators felt the Banks, “needed to be preserved in as natural a state as possible while allowing for development.”

The real trouble is finding a balance between the unrelenting push to develop and a piece of land that refuses to stay permanent.

“Barrier islands are, in their natural form, shifting islands,” Lineberger said. “Allowing them to shift is first priority to me. We humans can work around that.”

The biggest contention is construction on the coast, where yearly subtractions can accumulate into a big enough loss to remove a house.

“They use erosion rates to create setbacks for coast construction,” Overton said.  “That’s where any of the science of engineering techniques for understanding rate of change plays out in the public sector and impacts an individual who’s developing on the coast.”

The kinds of solutions that will bring balance to development will come from a combination of individual and public policy decisions, according to Overton.

“There are a lot of people in discussion on [what to do next],” Overton said. “It’s not simply the engineer, the personal property owner or one person in a state agency. It’s a policy decision on how to use that [scientific data] to manage development.”

Current policy takes the calculated annual rate of erosion, multiplies it by 30 and uses that distance as a marker for where developers can begin to build. But even this policy does not contain all the nuances of shoreline fluctuation.

“Most shorelines do not march back at a consistent rate. It has to do with sediment supply. It has to do with storms, human manipulation or construction,” Overton said. “There is a lot of variability in shoreline data, and we see more today given the advances in geospacial techniques and remote sensing, than we could have seen 30 years ago.”

In reality, the translation of the data is as complex as accumulating the figures.

“The issue is not our ability to describe a process as a scientist or an engineer,” Overton said. “Sometimes the issue is the need to balance multiple constituencies and points of view. How can you introduce the variability of shoreline position into policy?”

In particular, the power struggle between property rights and public domain issues can be a stalemate. Introducing further restrictions is difficult, particularly when a previously purchased lot becomes undevelopable under new laws, according to Overton.

However, for the average property owner the gradual effects of the erosion are not the greatest concern. Storms, like Hurricane Earl, produce the most devastating effects.

“Many of us thought [Earl] was going to be a very significant event,” Overton said. “It turned out that it downgraded fairly quickly.”

Still, for a community like the Banks, come high or low water, they are prepared.

“I think that they do see storms as part of their way of life,” Overton said. “People have lived out there for a long time, and there’s a sense of resilience in those communities. They know there are some things they’re not going to prevent.”

Most homeowners, whether on the mainland or the Banks, realize their homes are not permanent.

“The houses aren’t going to last 200 or 300 years. Your wood and screen door and toaster aren’t going to last that long,” Edge said. “[All the houses] will go away some time.”

Ultimately, sea level rise and gradual erosion may come into play in the future of policy.

“Earlier this year, the Division of Coastal Management adopted a one-meter rise in water level by 2100 as a planning number for the coast of North Carolina,” Overton said. “A one-meter rise would be a lot. There are some places that aren’t more than a couple of meters high.”

Lineberger predicts realizations like this will mean a lot more in the future.

“We’ve been taking a kind of hands-off approach, but it’s getting to the point where we can’t,” she said. “Short of hardened structures, the beach will move. 50 years is where you’re going to see the big effects.”

Edge hopes carefully-planned engineering solutions may be the key to keeping the Banks habitable.

“We have to plan and design so that we will have a sustainable environment, sustaining as much of the natural environment as we can while protecting the livelihood and enjoyment of those people [who live and vacation there],” Edge said.

Edge’s “Long-term Ocean Energy Program” incorporates a structure a couple of miles offshore, which would extract energy from the ocean and connect it to the electrical grid.

“If we can design these so they’re out in front of the Nags Head area,” Edge said, “we can generate electricity and reduce waves before they get to shore.”