The 'short bridge' to oblivion

January 1, 2010 

An alternative must be found to replace the aging Bonner Bridge over Oregon Inlet that provides the sole road connection between Hatteras Island and the North Carolina mainland, and soon. But state leaders are sticking their heads in the sand as they cling to a plan for a short replacement bridge to a precarious section of highway through the narrow and unstable north end of Hatteras Island.

The science is clear: Between storm events, global climate change, sea-level rise and the general instability of this type of barrier island, the short bridge replacement plan cannot work.

The proposed bridge and highway run through Pea Island National Wildlife Refuge, which occupies the north end of Hatteras Island (also called Pea Island, as it was once a separate island). Building a short replacement bridge to the northern tip of Pea Island requires the long-term maintenance of N.C. 12 through the refuge to connect the bridge to the eight villages on Hatteras and Ocracoke islands. Yet Pea Island is becoming increasingly incapable of supporting that road, and residents of the villages will inevitably be left isolated, without access to either the new Oregon Inlet bridge or the mainland.

The half-billion-dollar bridge will ultimately become a pier into the ocean, unreachable and unusable by the very people it was meant to serve.

Pea Island Refuge typifies a simple barrier island system, meaning that it is a low, narrow, sand-poor and more dynamic island than other higher and wider, sand-rich, complex barrier islands such as those at Avon, Buxton Woods and Ocracoke. With rising sea levels, Pea Island is migrating westward as storms and tides open inlets through the island and overwash deposits sand over the island.

However, these natural processes are impeded by ongoing efforts to protect the current, extremely precarious transportation corridor. For instance, sand that would naturally overwash the island, building island elevation and shallow back-barrier shoals to the west, is used instead to construct and maintain dune ridges to protect the existing road on ever-steeper beaches. The terminal groin installed to stop the erosion at the north end of Pea Island and prevent the bridge from becoming detached from the island is now, however, causing additional erosion of the eastern side of Pea Island.

The result of these processes is a net narrowing of Pea Island, making the transportation route more, rather than less, precarious. Construction and maintenance of the dune ridges to protect the highway cause the beach to narrow and steepen and prevent island overwash. This in turn prevents increases in island elevation and width, which are critical for island maintenance in a rising sea level. This makes the refuge less suitable for barrier island wildlife habitat, its primary mission, and also increasingly jeopardizes its ability to support the coastal highway.

As the island narrows, the ocean shoreline continues to recede westward at approximately 13 feet per year, with some sections receding even quicker. At its narrowest points, the refuge is already less than several hundred yards wide, and the highway is precariously close to the ocean for most of the length of the refuge. The surf continues to chew away at the road and, with time, new inlets will form, separating the planned bridge from the villages it was built to serve - long before the end of the bridge's useful life.

Indeed, in mid-November a nor'easter washed approximately 800 feet of N.C. 12 into the ocean and left more of it submerged under sand and water, stranding island residents for days.

If North Carolina truly cares about the well-being of residents and visitors on Hatteras and Ocracoke Islands, it will devote resources to designing and funding a safe, reliable transportation route to connect those islands to the mainland. The route, at a minimum, should function even during storms like the recent nor'easter and should not be rendered obsolete as natural processes change the character of Pea Island.

Several alternatives are far more sensible. A longer bridge connecting to the more stable part of the island would be preferable to the current short bridge plan. A system of modern, high-speed ferries and water taxies could serve high volumes of passengers even in fairly shallow waters and is another sensible solution.

The San Juan Islands, Channel Islands National Park and Cumberland Island National Seashore are examples of popular tourist destinations reached by ferry. Likewise, Ocracoke and Bald Head islands, Cape Lookout National Seashore and Hammocks Beach State Park have all been connected to the mainland only by ferry boats for their entire histories, and yet remain among the most popular tourist destinations on the North Carolina coast.

Stanley R. Riggs is distinguished research professor in the Department of Geological Sciences at East Carolina University. Julie Youngman is senior attorney at the Southern Environmental Law Center.

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