Nearshore placement of a sand dredged mound

Abstract

As a part of the Dredging Operations and Environmental Research (DOER) Program, movable-bed physical model experiments were performed at the U.S. Army Engineer Research and Development Centre's (ERDC), Large-scale Sediment Transport Facility (LSTF) to investigate the fate and evaluate the benefits of nearshore-placed dredged material. The resulting bathymetry was measured with detailed surveys, the migration of the mound was quantified and comprehensive observations of hydrodynamics were obtained. The potential suitability of dredged material placement in the nearshore/surf zone was demonstrated after 10 h of oblique wave attacks. It has been shown that, as the mound was located at the edge of the surf zone, very likely wave breaking induced horizontal circulation may be dominant. A downdrift accretion of the submerged beach was observed, which is due to the transport of part of the sediment suspended by breakers at the mound and captured by the longshore currents. The experiments provided useful validation data for numerical morphological models.