The beach strand at the north end of Figure Eight Island extends several yards beyond the first row of houses, but thousands of sandbags remain clustered around a little less than 20 homes, a reminder of the severe erosion that threatened development in the early 2000s.
For years, the waves crept closer and closer to the houses, eventually breaking over the sandbags during each high tide, said David Kellam, Figure Eight Island homeowners association administrator. Some visible, some buried beneath the new mounds of sand, Kellam views the sandbags as a 2,200-foot seawall, a temporary solution.
“Sandbags sink. They move up and down the beach. They break. They rupture. We want to eliminate the need for sandbags. A terminal groin is a viable option,” Kellam said.
The homeowners association hopes to replace the sandbags with a more lasting alternative: a terminal groin, one of four allowed in the state.
A pressing problem?
The homeowners association has pursued a long-term shoreline management plan for the north end of the island since 2006, Kellam said. A 2011 state law provided a path forward to construct a limited number of groins, which were previously illegal in North Carolina, opening the doors for Figure Eight Island to actively seek necessary approvals to construct a terminal groin to curb the impacts of cyclical erosion.
The proposed 1,500-foot groin, a low-lying rock structure built perpendicular to the shoreline, would hold sand on the northern end of the island that would otherwise drift immediately north into Rich Inlet, Kellam said, without causing serious repercussions to the surrounding area.
N.C. Coastal Federation Coastal Advocate Mike Giles disagrees. The federation has opposed the groin since it was first proposed based on a number of concerns about the impact to the nearby shoreline, endangered piping plovers and red knots that rely on the dynamic environment around inlets to feed and nest, and Figure Eight homeowners who will shoulder all costs to build — and, if necessary, mitigate consequences of — the project.
Today, Giles said that opposition is primarily motivated by a lack of need for erosion control mechanisms.
“If you go there now, there is no need for anything to be done. Mother Nature has taken care of the problem,” Giles said.
Kellam agreed a sense of urgency is temporarily suspended since the inlet channel shifted a couple of years ago, allowing sand to stick on the north end of the island. The problem will return, he said, because the channel moves back and forth within its bed roughly every 15 years. A spell of erosion similar to the one observed in the early 2000s threatened property owners in the mid to late 1980s, Kellam said.
“Sooner or later, all of this sand is going to erode away naturally, just like it has every 15 years,” Kellam said.
Robbing Peter to pay Paul?
Giles also wondered what costs, both financial and environmental, a groin might mitigate.
“When you put a structure like this on a dynamic North Carolina oceanfront beach, you rob Peter to pay Paul. You stop sand from its natural movement, so you’re robbing a sand source for somewhere else,” Giles said.
The groin was only proposed after years of research, Kellam said, to ensure it would not create other problems further down the coast.
“This is our backyard. We want to protect it as much as anybody,” Kellam said. “We live and play here. . . . If there was an error, if there was a bad mistake, it would fall mainly upon us and we would have to suffer the consequences of it. That’s why we did the research. That’s why we did the professional modeling by computer databases, over and over again. I want to be sure that we’re doing the right thing.”
Spencer Rogers, construction and erosion specialist for N.C. Sea Grant, said concerns about down-drift erosion caused by groins are warranted, but effects depend on the location and design of the structure.
“In the middle of any particular island, groins are generally not a good idea because you may solve one person’s erosion problem, but create a worse condition for somebody else. That’s what you worry about with a sand trap,” Rogers said. “There’s lots of sand moving back and forth along the beach. The question is, who’s going to benefit and who’s going to lose? In the middle of the island, it’s a pretty clear choice.”
Well-designed groins built on the tip of an island are less likely to present problems, Rogers said, because they are positioned at the end of the sand transport system.
“Just because it’s not a good idea in the middle of the island doesn’t mean it’s not a good idea for these terminal structures,” Rogers said.
Later this spring, the U.S. Army Corps of Engineers is expected to release a supplement to a 2012 draft report that outlined all possible solutions to Figure Eight Island’s erosion concerns. The supplement will detail a shorter groin, positioned further north than the one originally proposed in 2012, as another possible solution.
The supplemented report will be subject to a 45-day public comment period.