Field and Modeling Studies of Nearshore Morphology

Field and modeling studies of nearshore morphology aims to understand and predict sediment-transport mechanisms and their morphologic expression in the coastal marine environment, with particular emphasis on surf zone evolution. Principal goals are to effectively and economically predict bathymetric and sedimentologic evolution over a variety of time and length scales, to understand the degree of coupling between the scales, and to determine the level of uncertainty in predicting bathymetric evolution. Primary field focus was to study effects of insufficient sediment supply on nearshore morphology, such as that common to coastal North Carolina. ARO and CHL supported development of a LARC-mounted interferometric sidescan bathymetry system. The system simultaneously provides high-resolution. swath bathymetry and sidescan sonar images of the seafloor. Repeated surveys at the Field Research Facility at Duck, NC reveal outcropping muddy substrates associated with anomalous nearshore bar behavior in an otherwise sandy beach selling. Aerial photographs spanning a twenty-year period show persistent, recurring differences in bar morphology between the study site and adjacent areas. Video imagery also shows that the nearby shoreline has a much higher variance in erosion and accretion than the surrounding shoreline.