Nearshore Flow Dynamics Over Shore‐Oblique Bathymetric Features During Storm Wave Conditions

Abstract

Shore‐oblique bathymetric features occur around the world and have been statistically correlated with enhanced shoreline retreat on sandy beaches. However, the physical mechanisms that explain a causal relationship are not well understood. In this study, radar remote sensing observations and results from a phase‐resolved numerical model explore how complex morphology alters nearshore hydrodynamics. Observations at selected times during high‐energy storm events as well as a suite of idealized simulations indicate that shore‐oblique features induce strong spatial variations in the water surface elevation, wave breaking patterns, and mean current pathways. Re‐emergent offshore flows and longshore current accelerations occur near the shoreward apex of the oblique nearshore features. The results suggest that complex bathymetric morphology exerts a powerful control on nearshore hydrodynamics and increases the potential for enhanced cross‐shore and alongshore sediment transport.