Further analysis of wave overtopping effect on the nearshore hydrodynamics and morphodynamics reveals that wave overtopping has significant impacts on the nearshore circulation, sediment transport and the resulting morphological changes within such a complex breakwater scheme under the storm and macro-tide conditions. The model results were compared with laboratory data and field measurements, showing a good agreement on both hydrodynamics and morphological changes. The model was then applied to a study site at Sea Palling, Norfolk, UK, where 9 shore-parallel segmented breakwaters including 4 surface-piercing and 5 low-crested breakwaters are present, for the storm conditions in Nov 2006. The hydrodynamic aspects of the model were validated against a series of laboratory conditions. This paper describes the implementation of a wave overtopping module into an existing depth-averaged coastal morphological mode: COAST2D and model applications to investigate the effect of wave overtopping on the hydrodynamics and morphodynamics around a group of shore-parallel breakwaters. Wave overtopping nearshore coastal structures, such as shore-parallel breakwaters, can significantly alter the current circulation and sediment transport patterns around the structures, which in turn affects the formation of tombolos and salients in the nearshore area. Preliminary hydraulic design of the breakwaters was undertaken prior to further study by physical modelling. ![]() Numerical modelling results show an amplification of waveheights due to the combined shoaling and focusing effects of nearshore bathymetry for certain sectors of wave approach, including the direction of the highest deep-water waves, while for other directions exacerbated dispersion results in further reduction of the refracted waveheights. A detailed extremal analysis was performed on hindcast wave results verified against buoy and satellite data, investigating the goodness of fit for a large number of candidate long-term probability distributions. The present case study serves the two-fold objective of firstly addressing the less documented design context of single layer armoured breakwaters nearby a curved step-like bathymetric feature, while secondly striving for accurate design wave boundary conditions after numerical modelling of wave transformations on a fine spatial grid near the step-like feature to account for the localized effects on the design waveheights.
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