Sediment transport predictions for the English Channel, using numerical models

Output from an hydrodynamic numerical model (Salomon & Breton 1991a, b) has been combined with various empirical formulae to derive sediment transport rates and directions. The predictions are compared with radioactive sand tracer experiments, demonstrating the applicability of Gadd et al.’s (1978) expression. The derived bedload transport pattern for the area is consistent with sedimentological and geomorphological evidence, but provides improved resolution.A ‘bedload parting zone’ is identified for the central English Channel; this is well defined for sand movement, but seabed material present over this area (gravel) is not predicted to move significantly. The area is ‘non-erosive’, over which fine-grained sediments are being transported. A bedload convergence is located to the southwest of the Dover Strait, not in the Strait itself as proposed previously. A transport pathway, bypassing the convergence, along the French coastline (which is supported by radioactive tracer experiments) could be responsible for sand transfer from the English Channel to the southern North Sea