Seminar: UNC Wilmington

Sustainability of Barrier Island Protection Policies under Changing Climates

This project will address methods to adapt beach and dune nourishment to improve resilience in a changing climate. As storms become more powerful and seas continue to rise, major erosion events will occur more frequently. However, coastal communities do not yet understand how to evaluate their increasing vulnerabilities and adapt their long-term planning. In this project, we will identify the climate patterns that most often trigger the need to nourish, the variability of the time interval between such nourishments, and the economic costs and sediment volumes necessary to maintain this coastal protection policy into the 21st century.

A stochastic climate emulator will first be developed to simulate 1000s of realizations of chronological climate patterns (forced by satellite and GCM products) to create future storm events coupled with sea level rise scenarios. A library of high fidelity, open source, hydrodynamic and morphodynamic simulations (ADCIRC+SWAN and XBeach) will then be used to develop a surrogate model to predict erosion and flooding for each future realization. Triggers like beach width, dune height, and community preferences will be used to identify how often communities will need to re-nourish, contingent on future climate and sea level rise scenario.

JC Dietrich, DL Anderson. “Sustainability of Barrier Island Protection Policies under Changing Climates.” U.S. Coastal Research Program, 2019 Academic Research Opportunities, 2019/10/18 to 2021/10/17, $226,624 (Dietrich: $226,624).

News: Connecting Erosion to Flooding

2019/09/26 – NC Sea Grant Coastwatch
XBeach Model Predicts Storm Impacts on Beaches and Dunes

Alireza Gharagozlou (below) is a doctoral student in the Department of Civil, Construction, and Environmental Engineering at NC State University. He studies how to connect predictions of beach and dune erosion to community-wide flooding and serves with Casey Dietrich on NC State’s Coastal & Computational Hydraulics Team. North Carolina Sea Grant has supported their work.

Alireza surveying the beach profile near Hatteras, NC, with RTK-GPS after Hurricane Florence.

2019/04/26 – NC Sea Grant Coastwatch Currents
Model Predicts Storm Impacts on Beaches and Dunes

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During storms, strong waves and currents can erode beaches and dunes and create low-lying areas vulnerable to flooding. We use field surveys and a computer model called XBeach to predict this erosion, as well as to understand its interactions with storm-driven flooding of larger regions.

Computer models allow us to see how the storm surge and waves impact the beach over time, and which locations are vulnerable to large-scale damage. Good predictions of such storm impacts help emergency managers take better-informed measures to protect coastal areas. Understanding vulnerabilities also instructs highway access design and residential area planning.

We used the XBeach computer model on more than 30 kilometers of Hatteras Island between Avon and Rodanthe to explore how to connect erosion predictions to larger areas. Could XBeach cover more of the island, yet still provide good erosion predictions at beach and dune scales? And how could we connect erosion predictions to other models for storm surge and flooding?

Presentation: ASCE NC Fall Conference