Analysis swan hindcast tidal inlet of Ameland : storms of 17 December 2005 and 9 February 2006

An analysis has been made of the results of the SWAN hindcast study for the tidal inlet of Ameland performed by Royal Haskoning. Ten events in the storms of 17 December 2005 and 9 February 2006 have been hindcasted. An analysis was made to the origin of differences between observations and model results. This is achieved by analyzing the convergence behaviour of the simulations, and by analysing the differences between measurements and model predictions using the frequency spectra, the variation along rays, statistical analysis of integral parameters and a source term analysis. In addition, the effect of currents on the wave conditions has been assessed. The results indicate that SWAN generally under-predicts the period measures. The performance of SWAN becomes worse in southward direction. Long period North Sea waves do not seem penetrate into the Waddensea through the main channel. Instead they are found more to the west on the shallows. In the tidal inlet the processes of surf breaking and triad interactions are dominant. Further into the Waddensea, the wave conditions are mainly determined by local effects. The inclusion of currents slightly improves the performance of SWAN.