Sandbanks for coastal protection: implications of sea-level rise. Part 2: current and morphological modelling

The finite-element shallow-water solver TELEMAC-2D is applied to tidal flows in a region off the coast of East Anglia, UK, as shown in Part 1, for a period of 216 hours in year 2000. Boundary conditions for surface elevation and depth-averaged velocity are p rovided by the UK continental shelf model CS3 of the Proudman Oceanographic Laboratory, which uses a grid with about 11 km in the longitudinal and 18 km in the latitudinal directions. Digitised bathymetry from Admiralty charts was provided by METOC Ltd. under license. There is good prediction of tidal level measurement at Lowestoft provided by the British Oceanographic Data Centre. The sediment transport module SISYPHE is used to model morphodynamic change, assuming zero sediment flux gradient at the outer boundaries. Results showed a small net increase in sediment volume in the region, but importantly showed local regions of marked accretion on certain sandbanks, notably Scroby bank, mainly due to suspended sediment transport. The effect of Coriolis forcing is investigated. The aim of this Part is: to describe the methodology, including data management; deduce, as far as possible, the significant physical phenomena; determine qualitative effects; and discuss modelling limitations.