LONG-TERM EVOLUTION OF OFFSHORE SANDBANK MORPHOLOGY. CASE STUDY: GREAT YARMOUTH SANDBANKS, U.K.

摘要

It is evident from the existing literature that additional investigations into the evolution of offshore sandbanks are needed. In this paper we presented an analysis of the model output and relationship between the flow statistics and the historical sandbank configurations based on this background. A two-dimensional hydrodynamic model has been set up to investigate the long-term evolution of offshore sandbanks. Tidal simulations were performed with a nested model covering the Southern North Sea and Great Yarmouth zone (east coast of the UK). Simulations were carried out for a period corresponding to several spring-neap cycles and were compared directly with field measurements. The time series of velocities at each grid point were used to determine time mean tidal velocities and vorticity. The time series were also used to determine Reynolds stresses eddy vorticity fluxes. The spatial patterns of these quantities are studied for two separate charts, relating to 1945 and 1954. The correlation between the evolution of the sandbanks and the residual and eddy flow statistics suggests that they could be a useful tool for coastal planners to develop an improved method of estimating long-term sandbanks changes.