Date of Award

Spring 2013

Project Type

Thesis

Program or Major

Earth Sciences - Ocean M apping

Degree Name

Master of Science

First Advisor

Tom Lippman

Abstract

High-resolution seafloor topography and coincident mean currents were obtained in Hampton Harbor Inlet over a fortnightly tidal cycle. Nine multibeam echosounder surveys were conducted in the inlet navigation channel, and mean currents were measured throughout the inlet using an acoustic current profiler mounted on a movable personal watercraft. Maximum mean currents of 1.5 m/s were observed and coherent bedforms, ranging in size from sand dunes to mega-ripples, were present throughout the inlet navigation channel. Spatial variation in bottom roughness showed that mega-ripples evolved spatially and temporally over the study. A series of 8 sand dunes migrated steadily onshore, up to 8 m, during neap tides and steadily offshore, up to 15 m, during spring tides. The net movement of sand dunes over the study was offshore, indicating higher flows during spring tides that dominated net sediment transport. Higher shear stress estimates during spring tide validate observations of bedform migration.

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