Date of Award

Spring 2021

Project Type

Dissertation

Program or Major

Earth Sciences

Degree Name

Doctor of Philosophy

First Advisor

Thomas C Lippmann

Second Advisor

Thomas C Lippmann

Third Advisor

Jesse E McNinch

Abstract

This body of work examines the hydro- and morpho-dynamics of tidal inlets using a diverse array of research tools. A custom X-band radar system (RIOS) is designed and used to track the evolution of shoal features over the ebb-tidal delta at Oregon Inlet, NC. Analysis of the data reveals that alongshore shoal migration rates are closely correlated to wave driven alongshore sediment transport, and also that the cross-shore bedform migration rates are tightly correlated with a sub-tidal water level gradient though the inlet. A follow up experiment with in-situ sensors suggests that the sub-tidal gradient is set up by regional winds and that the resulting pressure gradient significantly alters the tidal inlet hydrodynamics, at times entirely reversing tidal flows. Finally, the geomorphic impact of wind driven currents, as well as waves and the insertion of a terminal groin, is tested through an idealized numerical modeling study of a synthetic inlet system. The addition of a sub-tidal water level gradient has substantial and cascading effects on the inlet system morphology, potentially suggesting that the traditional inlet classification system, based only on wave and tidal properties, should be modified to include wind influence.

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