Engineering News-Record: Shoring up for rising sea levels

December 16, 2020

From atop the gantries being used to erect the Rodanthe Bridge in North Carolina’s Pamlico Sound, a worker can look across the sands of windswept Hatteras Island and see Atlantic Ocean waves pounding the shoreline next to the two-lane State Route 12, the sole road connecting a chain of tourism-dependent villages to the mainland. The view is a reminder of why the North Carolina Dept. of Transportation is spending $145 million to build the 2.4-mile-long elevated road.

The bridge will bypass an area of Route 12 called the S Curves, which in 2011 required a $3-million emergency repair effort to fill and cover a temporary inlet created by Hurricane Irene, and a $20-million U.S. Army Corps of Engineers-funded beach nourishment project the following year. NCDOT monitoring data shows the S Curves’ oceanfront is being eaten away at a rate of 11 ft to 12 ft per year. Forecasts for 2060 indicate that even under low-erosion scenarios, other sections of the 12.5-mile corridor will be similarly vulnerable to encroachment.

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“You can’t just pick up a road and move it,” says Annie Bennett, a senior associate with the Washington, D.C.-based Georgetown Climate Center. “It points to the importance of planning and integrated decision-making.” Even with that, Bennett adds, the process can be complicated and fraught with political pushback, as localities and governing agencies wrestle with issues such as land use and acquisition, public safety and environmental mitigation. Efforts to achieve consensus on infrastructure relocation have been aided in recent years by improvements in data collection that narrow global-scale climate trends down to specific, close-to-home impacts. “It’s a matter of making the case in a way that resonates locally, and gets the conversations started,” Bennett says.

Read the full article by Jim Parsons in Engineering News-Record