Barrier island evolution in relation to sea-level changes: the example of the Grado Lagoon (northern Adriatic Sea, Italy)

Air-photographs, maps and repeated field surveys dated from 1882-1990 were used to define the evolutionary patterns of the new coastal barrier of Grado Lagoon between Porto Buso and Grado. The shoreline retreat model ("generalized Bruun Rule") was tested. This model can be used as a first approximation in prediction of shoreline movement following the sea-level rise, and considering the general prevalence of the transverse movement in this specific area. The results achieved allowed the authors to modify the Bruun-based model for prediction, in specific cases, of the alongshore sediment movement. Differences between the model and observed values in several cases are rather high and are interpreted as a result of tidal movements and alongshore sediment transport.