IN-SITU AGGREGATE SIZE AND SETTLING VELOCITY IN THE OOSTERSCHELDE TIDAL BASIN (THE NETHERLANDS)

Suspended aggregate size and settling velocity at sediment concentrati ons <10 mg.dm-3 were determined in situ from aggregates sampled by a d iver and from observations by a submersible video camera in September and November 1991. Aggregate size and settling velocity were up to 150 0 mum and 1 cm.s-1, respectively. Aggregate size, settling velocity an d density were highest during flood and high-water slack, which points to flocculation and settling during flood and high-water slack, and n o resuspension by the ebb current. This agrees with the observed landw ard transport of fine-grained sediment inside the basin.