Outer Banks beach erosion gets a fresh look

As one bad storm after another chews away at Outer Banks beaches, the prospect of loosening the state's ban on hardened erosion-control structures is becoming more appealing here.

The rock wall on the southeast side of Oregon Inlet, built to protect the Herbert C. Bonner Bridge, is one of five sites that the state is studying to determine the feasibility and advisability of using terminal groins to stem sand loss along North Carolina's coastline.

Terminal groins are low-slung barriers of steel or rock that are designed to trap sand in near-shore currents, and allow excess sand to pass over them. Typically, they're at the ends of islands or by inlets.

Since construction of the 3,152-foot Oregon Inlet groin in 1989, the beach in front of the historic Oregon Inlet Life-Saving Station and near the bridge has widened, possibly saving both structures from destruction. That's an observation not lost on barrier island residents and officials looking for ways to keep sand on eroding beaches and out of clogged navigational channels.

"There's a whole bunch of us down there in South Nags Head, and we just kind of wonder why a terminal groin at the north end of Oregon Inlet wouldn't also solve the problem of Oregon Inlet filling up," said John Ratzenberger, a Nags Head resident, at a public hearing last week in Kill Devil Hills.

"From a citizen's point of view, that sounds like the perfect test case."

Part of what the groin study will consider are findings in a separate long-term analysis by North Carolina State University coastal scientists of the Oregon Inlet groin's impact on the nearby road and shoreline. It will also look at the degree that sand replenishment on the beach south of the groin has mitigated any potential erosion.

The state Division of Coastal Management is holding public hearings throughout the state to get input on the study, which was mandated this year by the General Assembly. The state Coastal Resources Commission is overseeing the study and will present its report by April 1.

Since 2002, state law has banned most use of hardened structures on shorelines because they can cause increased erosion on surrounding beaches. Under the law, groins are allowed only to protect certain bridges, historic sites and significant navigation channels.

Prior to 2002, a similar coastal rule restricting use of terminal groins had been in place since the 1980s, but the structures could be permitted with a variance.

Jan DeBlieu, Cape Hatteras coastkeeper for the North Carolina Coastal Federation, said during the public comment period that the structures cause downdrift erosion, creating problems further down the coast.

"The best way to control a barrier island is to allow it to be natural and open," she said.

Engineers with the Raleigh firm Moffatt & Nichol have been contracted by the commission to conduct the study. The state Science Panel on Coastal Hazards is reviewing methodology, including an analysis of the effectiveness and potential environmental and economic impacts of terminal groins.

James Gregson, director of the Division of Coastal Management, said there has been increasing pressure from coastal communities to have "more tools in the toolbox" to address beach erosion.

But he acknowledged that the state's coastal managers are "a little worried" about softening the state's decades-long stance against hardened structures on the coast.

"The concern," he said, "is that this will open the door to other things, such as seawalls and revetments."

Catherine Kozak, (252) 441-1711, cate.kozak@pilotonline.com