Coastal Hazards Infrastructure Vulnerability Assessment Completed by Western Carolina

In February 2020, Western Carolina University’s Program for the Study of Developed Shorelines completed a Coastal Hazards Infrastructure Vulnerability Assessment for the Town of Duck, North Carolina. This assessment evaluated individual buildings and roads, allowing the Town to compare the vulnerability of individual assets to develop more detailed adaptation plans and strategies. The assessment focused on roads and a subset of commercial, professional, retail, and publicly-owned buildings in and around Duck Village. Most of the buildings evaluated are concentrated along Duck Road (N.C. Highway 12) in close proximity to the Currituck Sound. In total, 65 buildings and 308 road segments (almost 32 miles) were included in the vulnerability assessment.

Vulnerability is generally defined as the extent to which a resource is susceptible to harm from hazards or climate change impacts. For infrastructure (assets), vulnerability is most often calculated as a combination of exposure and sensitivity. Exposure refers to the extent or degree to which climate change or a natural hazard is likely to affect an asset, and sensitivity refers to how it will fare when exposed to a hazard/impact. The coastal hazards evaluated in the assessment include flooding, storm surge, sea-level rise, and erosion. The assessment found that, compared to many barrier island communities, Duck has relatively low overall vulnerability due to its unique sheltered coastal setting and significant interior elevation. Although Duck has these beneficial factors, it still has significant exposure to certain coastal hazards: primarily coastal erosion on the oceanfront and flooding on the soundside. Winter nor’easters can also significantly subject this part of the coast to erosion, flooding, and waves over multiple days.

The study concluded that the vulnerability of existing structures in Duck can be reduced through two primary adaptation measures: elevation and/or relocation. While these adaptation actions may not always be practical, they are the most efficient ways to decrease the vulnerability and increase the resiliency of existing infrastructure. These adaptation options can be considered following storms when funds may become available for resilience actions. To increase the resilience of any future development in Duck, the safest bet is to place new infrastructure in areas that have minimal exposure to hazards. When that is not possible, adopting higher standards for building elevation and construction can lead to more sustainable infrastructure over the long term.