Research Seminar: Jessie Straub

A research seminar from UNC Marine Sciences graduate student, Jessie Straub. Presented by the UNC-CH Department of Marine Sciences and UNC’s Institute of Marine Sciences (IMS). The main location of this event will be in seminar room 222 at IMS in Morehead City, NC. The seminar will be streamed live to room G201 on the ground floor of Murray Hall on UNC-CH campus in Chapel Hill, NC. This event will be held on Monday, October 1st at 12:20pm.

Seminar Title: Evaluating the potential for coastal dune erosion during storms

Abstract: Coastal communities commonly expend resources on the conservation and restoration of dunes because they provide natural protection from storm waves and flooding. Dune morphology is dynamic, constantly changing in shape, width, and height due to changes in winds, waves, and water levels. Identifying coastal areas that are vulnerable to dune erosion is increasingly important as coastal population and development continue to increase, beaches narrow, and the exposure of coastal communities and infrastructure to ocean flooding increases. Information necessary to predict dune erosion includes data on coastal waves, water levels, and foreshore beach slope. Accurate wave and water level data is difficult to obtain away from buoys, and beach surveys are commonly outdated and might not reflect current conditions. Here, we present preliminary results of predicted dune erosion based on: wave runup equations from Stockdon et al. (2006); hindcasted nearshore water levels and waves from the coupled ADCIRC+SWAN (ADvanced CIRCulation + Simulating WAves Nearshore) model; and contemporary beach topography data derived from UAS (Unoccupied Aircraft Systems) imagery and terrestrial laser scanning. Water-level loggers and cameras were installed at the toe of the dune at Core Banks (high-energy site), Shackleford Banks (cape influenced site), and Onslow Beach (low-energy site) to verify model results by recording inundation levels and dune erosion events. Preliminary results for events that occurred shortly after shoreline morphology was surveyed, indicate model predictions from Core and Shackleford Banks are in reasonable agreement with observed wave runup and dune erosion. However, due to rapidly-changing dune elevation and beach slope, future work will examine the accuracy of dune erosion prediction as the time between topographic surveys increases. In addition, the wave runup model will be applied to Onslow Beach, parameterized over the 2012-2014 period and compared to observed dune erosion events. This research provides insights into the challenges associated with predicting dune erosion and ultimately incorporating dune erosion as part of a coastal forecasting system.