Sediment Flushing after Dredging in Tidal Bays

A one-dimensional dispersion model for tidal flushing of suspended material has been formulated. It is suggested that this model can be used to predict the escape of suspended material from an astuarine dredging area out into the adjacent waters. The dispersion model includes a sedimentation function to reproduce the effect of resedimentation. Calibration of the model was carried out in a restoration area by means of in-situ tracer tests and salinity measurements to establish the dispersive properties of the water body. The settling characteristics of the upper sediment layer were established by sedimentation analysis of bottom samples from the dredging area, divided into an organic (polluted) top layer and the underlying inorganic sediment.