Patterns of Bedform Migration and Mean Tidal Currents in Hampton Harbor Inlet, New Hampshire, USA

TitlePatterns of Bedform Migration and Mean Tidal Currents in Hampton Harbor Inlet, New Hampshire, USA
Publication TypeThesis
Year2013
AuthorsMcKenna, Lindsay
Degree and ProgramMaster of Science, Earth Sciences: Ocean Mapping
Number of Pages117
Date Published05/2013
UniversityUniversity of New Hampshire
LocationDurham, NH

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.