PhD Dissertation Defense: Carter Smith

The PhD Dissertation Defense of Carter Smith will be presented by the University of North Carolina at Chapel Hill Department of Marine Sciences and Institute of Marine Sciences. The main location of this event will be in room 222 of UNC’s Institute of Marine Sciences in Morehead City, NC. The defense will be streamed live to conference room 3204 on the 3rd floor of Murray Hall on UNC main-campus in Chapel Hill, NC. This event will be held on Friday, February 22nd at 9:00 am.

Title: The socioeconomic and ecological effects of shoreline hardening with implications for nature-based coastal protection

Abstract: Widespread shoreline hardening, or the placement of hard engineered structures along coastlines for the purposes of reducing erosion and protecting infrastructure, has been shown to have adverse effects on coastal ecosystems. In order to enhance coastal sustainability and resilience, scientists have recently advocated for the incorporation of natural habitat elements into shoreline protection schemes (i.e. living shorelines). The overall objective for this dissertation was to take an interdisciplinary look at the socioeconomic and ecological effects of shoreline hardening, in order to design living shoreline alternatives that meet homeowner needs. First, we sought to understand which factors influence how waterfront property owners select shoreline stabilization approaches (Ch. 1). We found that homeowners were more concerned with structure cost, effectiveness, and durability, than ecological impact, and that they perceived vertical walls to be their best shoreline stabilization option. To test this assumption, we conducted a field survey of hardened shorelines, natural shorelines, and living shorelines before and after Hurricane Matthew (Ch. 2). This study demonstrated that living shorelines were just as resistant to landward erosion as hardened shorelines, but they did not require any repair after the storm and also maintained coastal saltmarsh over time. Nevertheless, this study did not investigate damages to upland infrastructure, and thus we conduced a follow-up survey that investigated the best predictors of shoreline and home damage during Hurricane Matthew (Ch. 3). This survey revealed that a higher percentage of homeowners with bulkheads versus natural shorelines reported home damage during the hurricane, likely because homes with bulkheads were on average twice as close to the shoreline as homes with natural shorelines. Finally, we used a Dual-Frequency Identification Sonar to investigate fish use and structural affinity along natural, bulkhead, and living shorelines (Ch. 4) and we found limited differences in fish detections among shoreline types. Overall, this dissertation demonstrates that homeowner-identified priorities of effectiveness, durability, and low cost are not being met by hardened shorelines in North Carolina and that living shorelines have the potential to meet homeowner needs while maintaining valuable ecosystems and enhancing coastal resilience.