In situ aggregate size and settling velocity in the Oosterschelde tidal basin (The Netherlands)

Abstract

Suspended aggregate size and settling velocity at sediment concentrations < 10 mg·dm −3 were determined in situ from aggregates sampled by a diver and from observations by a submersible video camera in September and November 1991. Aggregate size and settling velocity were up to 1500 μm and 1 cm·s −1, respectively. Aggregate size, settling velocity and density were highest during flood and high-water slack, which points to flocculation and settling during flood and high-water slack, and no resuspension by the ebb current. This agrees with the observed landward transport of fine-grained sediment inside the basin.