Seasonal Effects and the Impact of Beach Morphology on the Variability of Water Line Positions

The daily maximum landward position of the waterline at the sandy beach of Noordwijk, the Netherlands is measured with an Argus video system over 2001 and 2002, and used to compute exceendence lines for different time periods. The maximum landward position is related to the high-tide level and wave induced water level elevations, like storm surge levels and wave set-up levels. Seasonal variations of positions are clearly observed, with the maximum landward positions and the largest cross-shore spreading of the exceedence lines in the fall and winter season. The spatial variations over a 600 m stretch along the shore are small and mainly influenced by the intertidal barred beach morphology under low-energetic wave conditions.