Dominant processes and sediment mobility on a sandy tidal flat: Martens Plate, German Wadden Sea

Abstract

Monitoring of bedforms and depth of sediment mobility on Martens Plate in the German Wadden Sea shows that waves are more important processes than tides on a back-barrier intertidal environment subjected to tidal ranges of 3m. The tidal flat surface is wave-dominated and produces only wave or combined-flow ripples. The depth of sediment disturbance in this area is generally less than 3 cm. At the tidal channel margins, small ebb-oriented dunes are dominant. They exhibit a depth of sediment disturbance of up to 20 cm and migrate less than one wave length during a single tidal cycle. The areal extent of wave-dominated sedimentation is several times that of tide-dominated processes. Overall depth of disturbance is approximately equal to bedform height regardless of dominant processes or geomorphic location.