Date of Award

5-2022

Document Type

Thesis

Degree Name

M.S.

Department

Civil, Coastal, and Environmental Engineering

Committee Chair

Bret Webb, Ph.D.

Abstract

Infragravity (IG) waves are responsible for large volumes of sediment transport in the nearshore environment and therefore have a large influence on morphological changes to barrier islands, especially during extreme event scenarios. While IG waves have been studied at length in the nearshore, less research has been dedicated to their behavior and contributions to morphological change of barrier islands during extreme event overwash and inundation. Continuous measurements of water pressures were collected along two cross-shore transects on Dauphin Island, AL during Hurricane Nate (2017). Using small-amplitude wave theory, instantaneous water elevations were estimated from these pressures. In this study, these elevations are filtered to separate waves into their IG and surface gravity wave components, and their changes across the transects are observed and reported. IG wave energy is found to comprise a majority of the total wave energy, and its relationship to water depth and morphological change is analyzed. As a general observation, IG wave energy increases with water depth until a certain point where the energy starts to decrease, likely due to a breakdown of IG wave generation mechanisms, while inundation continues to its peak depth. It is found that locations that experienced high IG wave energy experienced high cross-shore sediment transport during the storm.

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