Mesoscale temporal changes to foredunes at Inch Spit, south-west Ireland

The history of foredune development and loss is examined on a decadal-scale basis at Inch Spit at the head of Dingle Bay. Inch currently has a foreland area (2 km(2)) with four low foredune ridges fronting the southern section (2.5 km) of the barrier. Analysis of maps (1842 & 1898) airphotographs (1949, 1967 gr. 1973) and field surveys (1993/94) of the shoreline has supported an interpretation of two to three possible sequences of sudden erosion of the foredunes and subsequent redeposition and reworking of foredunes over periods of 30 to 50 years. The erosion and deposition of the foredunes have been analysed in terms of variation in the following; human activity, sea-level, storm activity and longterm (annual to decadal) atmospheric forcing changes, but none of these factors individually account for foredune changes. It is argued on circumstantial evidence that the role of extreme storms and associated surge is the most probable key to understanding sudden foredune disappearance. Wave refraction modelling of extreme events has helped to specify the principal control on foredune loss. The result of specific microscale triggers (days) leading to mesoscale changes (decadal) is examined.