2004 Volume 48 Pages 775-780
In the Tone River Estuary, turbidity maximum (TM) is formed in the reach of 5km below the estuary barrage. The TM region is covered by fine sediment having the mean diameter of 10μm. The sediment repeats resuspension and deposition following the variation of flow field. Time variation of SS distribution in vertical showed almost the same tendency at many points in the TM region. This fact means that the measurement and analysis in one-dimension in vertical can be applied to investigate the sediment behavior in the region. Sediment pick-up rate obtained from the one-dimensional analysis on the budget of suspended sediment was found to have a high linear correlation with the shear velocity obtained by the log-low fitting for measured velocity profile. The critical shear velocity for resuspension was shown to be a small value of 1.8×10-3m/s, which was the same order as the value of ‘non-cohesive’ sediment. It would be caused by the surface bed sediment having a high water content due to the repeating motion of resuspension and deposition.
