Hindcast Petten and Westerschelde with SWAN 40.20 : period correction SWAN 40.20

The SWAN model version 40.20 has been used to hindcast 5 storms near the Petten Sea Defence and 3 storms in the Westerschelde. Two hindcast methods have been used; a relatively simple standard method and an advanced method in which a better description of boundary condiitions has been used. The results indicate that for both areas the initial under-prediction of the significant wave height is changed into an over-prediction of equal magnitude in the advanced method. For the mean wave period the initial under-prediction is reduced. The scatter in the results remain large. Since the prediction errors ar still rather erratic, generic correction factors need to be derived based on an error analysis of the responsible physical conditions and processes at various locations.