Variations in Sediment Strength along the Tidal Inlet Channel near Pea Island, NC

The sound-side shoreline of Pea Island located on the Outer Banks, NC, has been eroding over the last two decades. As part of the pilot During Nearshore Event Experiment (DUNEX) carried out in October 2019, sediment strength, grain size, and currents were measured in a tidal inlet flood channel in the back-barrier zone of Pea Island using a portable free fall penetrometer, grab samples, and an acoustic Doppler current profiler. Results indicate a general trend of a decrease in the surficial (upper 10 cm) sediment strength toward the shoreline (from 130 to 75 kPa) and from downstream to upstream (from 150 to 70 kPa). The cross-shore directed trend can be explained by sediment fining toward the shoreline with a lowest median grain size of 22 mu m. Variations in sediment strength were related to current velocities and local sediment transport processes; thus, the results contribute to a better understanding of the erosional processes of the sediments.

Automated summary

The sound-side shoreline of Pea Island in North Carolina has been eroding over the past two decades, with a pilot study in October 2019 showing a general trend of decreasing sediment strength towards the shoreline and from downstream to upstream in a tidal inlet flood channel. Variations in sediment strength were found to be related to current velocities and local sediment transport processes, contributing to a better understanding of erosional processes.