Morphodynamics of intertidal bar morphology on a macrotidal beach under low-energy wave conditions, North Lincolnshire, England

The morphological changes of multiple intertidal bars (ridges) on a macrotidal beach were examined under low-energy wave conditions during a spring-to-spring tidal cycle. The morphological response was coupled to the tidal water level variations and related residence times for swash processes and surf (breaking waves and: bores) over the cross-shore profile. Spring tides induced a large spatial variation in water lines and small residence times for distinct processes. Neap tides narrowed the intertidal area and increased the time for certain processes to work on the sediment at one location. The observed morphological changes could be coupled to the stagnation of processes at. a certain bar crest position. The action of surf (breaking waves and bores) played the major role in the onshore migration of the intertidal bars and the simultaneous erosion of the seaward flank. Swash action, responsible for the generation and migration of intertidal, bars in microtidal settings, was not the, dominant, process in, causing the observed morphological changes. Intertidal ridges on macrotidal beaches cannot be considered swash bars, as suggested by most previous investigations into these morphological features. (C) 2002 Elsevier Science B.V. All rights reserved.