MODELING SEDIMENT FLUXES IN ESTUARINE WATERS USING A CURVILINEAR COORDINATE GRID SYSTEM

A boundary-fitted finite-difference numerical model, capable of predicting two-dimensional depth-integrated tidal flows, has been refined and extended to include sediment transport processes. The sediment fluxes have been considered as the sum of both suspended and bed load fluxes. The highly accurate ULTIMATE QUICKEST scheme has been used to represent the advective terms in solving the advective-diffusion equation for suspended sediment transport. Considerable effort has also been directed towards the development of an appropriate source-sink term to represent the erosion and deposition of the bed material which does not depend upon the vertical distribution profile calibrated at the site. The model has been applied to simulate tidal flows and sediment fluxes in the Humber Estuary in the U.K. The predicted velocities and water elevations have compared favourably with measured data, thereby leading to the potential for accurately predicting sediment concentration distributions. Comparisons between the numerical model predictions of sediment fluxes and field data were also made at three sites along the estuary where field data existed. Overall the quality of these comparisons was encouraging, particularly since no tuning was necessary. (C) 1995 Academic Press Limited