Clara Armaroli

Title: MICORE: DUNE EROSION AND OVERWASH MODEL VALIDATION WITH DATA FROM NINE EUROPEAN FIELD SITES

In this paper we present the first results of beach profile hindcasting with XBeach using recently measured coastal data acquired under storm conditions at eight European sites, including a comparison to model results obtained with off-the- shelf models. The results show consistently that the XBeach has skill in predicting the coastal profile, albeit that in most cases the erosion around the mean water line is overpredicted and the depositions at the lower beach face are overpredicted. The causes for this model effect are under active investigation but not resolved yet. Likely candidates are the modeling of onshore (asymmetry) transports which reduces the offshore transports due to undertow (currents) or the modeling of sediment motion in the swash zone.

SEDIMENT TRANSPORT PATTERN AND COASTAL EVOLUTION AT LIDO DI DANTE BEACH, ADRIATIC SEA

Inter-disciplinary medium term monitoring of a small coastal cell of the Northern Adriatic, Lido di Dante Beach, was undertaken starting from 2001. In association with the EU-CoastView Project, coastal state indicators were developed and surveyed. This paper presents the observations done during 3 years of surveys: beach morphodynamics, intertidal bars, dune morphology and vegetation, overwash observation and risk. Results evidence two areas with different dynamics: the Southern part of the beach is dependent on the Bevano River by-pass processes and all indicators are positive (stable vegetation, large beach) while the Northern part is very narrow, eroding (10m/year) and the dune is easily overwashed. This atypical behavior is though to be due to the groin that disturbs the protective function of the nearshore bar system.

BAR CHANGES DUE TO STORM EVENTS USING ARGUS: LIDO DI DANTE, ITALY

In this study sand bars were analyzed using remote sensing techniques. An Argus system was installed at Lido di Dante, a small village near Ravenna, in northern Italy. The study period is between April 2003 and May 2004. Timex video images were used to analyze bar dynamics. Pixel luminosity intensity was sampled along 15 cross-shore profiles, 50m spaced. The system was perturbed by a storm event occurred in December 2003. Before this event the bars were undulated with 2 wide crescents, after the event the crescents became 5. Before and after this event the system was stable and it maintained a constant configuration. A preliminary conceptual model is presented: the system is self-organized, by redistribution of sand within a delimited longshore area, even under low energy conditions. When an energetic event occurs, the system changes, but it recovers its stable configuration within a short time (6 days).