A 3-DIMENSIONAL FINITE-DIFFERENCE MODEL FOR COMPUTATION OF NEAR-FIELD AND FAR-FIELD TRANSPORT OF SUSPENDED MATTER NEAR A RIVER MOUTH

A three-dimensional model for the dispersion of suspended sediment after a point release of dredged material in a stratified area of the coastal sea is described. To obtain good near-bottom resolution a vertical coordinate transformation is applied. A finite difference method, which is non-negative and accurate for concentration clouds smaller than the grid mesh size, is used for the computation of the dispersion of fine sediment. The model is applied to a part of the Dutch coastal zone. Transport paths of suspended sediment are computed, revealing a strong residual eddy north of Hoek van Holland, the main outlet of Rhine river water.