Bed-level Change Over Individual Swash Cycles On Sand and Gravel Beaches

This paper describes two large field campaigns designed to obtain the most comprehensive dataset to date of morphodynamic change in the swash zone and the associated hydrodynamic processes. Experiments were undertaken at a sand and gravel beach to provide complimentary data from contrasting beach types. An initial analysis of the data revealed that relatively large bed-level changes (1 – 2 cm) were observed to occur in response to individual swash events. Indeed, itwas found that the net morphological changes over a 2-hour section of data were not caused by the gradual accumulation of small bed-level changes, but in fact the morphological response was dominated by a small number of large events which had the same order of magnitude as the overall bed-level change during the entire time-series