Considering an arbitrary cross shore profile along the Dutch coast a marine zone and an aeolian

The coastal system consists of a sub-aqueous and a sub-aerial zone which can be separated by a border. At this border sediment exchange takes place from one zone to the other. This paper hypothesizes that conditions and therefore sediment exchange at this border are dependent on active profile characteristics. To analyze morphological developments due to combined marine and aeolian processes data acquired at a measurement site located along the southwest Holland coast is exploited. Based on the monthly morphological profile measurements the border between the marine and aeolian zone is determined. It is found that during accretive conditions the vertical location of this border, and with that the conditions near the border, is dependent not on the foreshore slope of the surf/swash zone as expected but on the slope of the entire active profile.