Intertidal bars are naturally occurring morphological features along the waterline of sandy beaches. Present quantitative knowledge on intertidal bar behavior is limited, due to the scarcity of data resources and the limitations of traditional survey techniques. To investigate and quantify the cross-shore morphologic behavior of intertidal bars, hourly terrestrial laser scans of Kijkduin beach (The Netherlands) are used and a conceptual evolution intertidal bar model is constructed. In a six-week period in January and February 2017, a pronounced intertidal bar formed at Kijkduin beach and migrated onshore during mild wave conditions and eroded again during storm conditions. The observed maximum shoreward migration was 30 m horizontally with a maximum growth of about 1 m in the vertical direction. Onshore sediment transport fluxes peaked around 2 m³ per m width per day. In the conceptual model proposed here, run-up and overwash processes are dominant for shoreward growth and migration of the bar and submersion processes are responsible for bar destruction.

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The intertidal zone is an important coastal zone linking the shore with the sea and it acts as an interface between the marine and aeolian zone facilitating the transfer of sand underwater and the beach. It is an extreme environment where water, sediment, wind and ecology constantly interact with each other under continuously changing conditions which impede the acquirement of reliable measurements. The utilization of a permanent laser scanner within the CoastScan project has provided the opportunity to monitor the beach hourly for a six month period resulting in a detailed image of the height variations of the intertidal zone. The analysis of the data shows the development of multiple bars in the intertidal area which can partly be coupled to external meteorological and hydrodynamic conditions.@en