For most state DOTs, summer is a time to catch up on maintenance backlogs, tackling roads and bridges that are due for makeovers, as well as those battered by whatever weather Mother Nature doled out over the winter.
On Hatteras Island, N.C., the North Carolina Department of Transportation’s focus this summer is more preventive in scope—protecting Route 12, the narrow barrier island’s only major roadway, from the onslaught of storms that typically bury the pavement in sand or, worse, scrape it away completely.
At a washout-prone “hot spot” just north of the village of Rodanthe, NCDOT plans to begin a beach nourishment project in July that will provide some measure of protection until the agency can move forward on a permanent bridge. The three-year project, developed with the National Park Service and U.S. Fish and Wildlife Service, will widen the existing oceanside border of Route 12—currently little more than a narrow dune reinforced with sandbags—by 100 yards over a distance of approximately two miles. The area has experienced severe erosion over the past decade, with many beachfront houses either relocated or given away to the surf.
As for the new bridge, NCDOT expects to select a preferred alternative this summer, and award a construction contract late this year or in early 2015.
At another hotspot in the Pea Island National Wildlife Refuge, a permanent solution is already under construction. A new 2.4-mile, $124.2 million structure will lift Route 12 as much as 32.8 feet above the gradually eroding shoreline where inlets have repeatedly opened and closed since before humans arrived on the island.
In addition to replacing a temporary steel structure erected following Hurricane Irene in 2011, the permanent bridge is designed to provide 15.8 ft of clearance above the mean high water level at its highest point.
NCDOT’s summer schedule also includes completing feasibility studies to address other Route 12 erosion hot spots on Hatteras Island, and nearby Ocracoke Island. Alternatives under study include beach nourishment, road relocation, bridges, or a combination of options.
Meanwhile, the keystone of Route 12’s ruggedization—replacing the half-century old Bonner Bridge over Oregon Inlet—remains stymied by federal lawsuits contending that NCDOT’s strategy does not adequately address environmental concerns in the Wildlife Refuge. With the case awaiting action in the 4th Circuit Court of Appeals, NCDOT conducts a variety of visual and sonar scans to keep tabs on the structure’s health.
Last fall, the bridge was closed for nearly two weeks due to excess scour around some of its support columns. The latest quarterly scan of the bridge’s deck, conducted on June 2, showed no significant movement.