Wind, Wave, and Engineering Effects on Tidal Inlet Morphodynamics

TitleWind, Wave, and Engineering Effects on Tidal Inlet Morphodynamics
Publication TypeThesis
AuthorsHumberston, J
Degree and ProgramDoctor of Philosophy
Number of Pages146
Date PublishedMay 4
UniversityUniversity of New Hampshire
LocationDurham, NH

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.