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Article Dans Une Revue Journal of Coastal Research Année : 2014

Evolution of Corsican pocket beaches

Résumé

Pocket beaches are small beaches that are formed between headlands in coves on rocky shorelines. They can be composed of a mix of boulders, pebbles, sand and mud and therefore have the attributes of a combination of shoreline types. Their evolution depends on wave forcing and morphological characteristics, and the most commonly observed dynamics is the beach rotation due to prevailing wave direction. In this study, 44 pocket beaches of Corsica Island, in the Mediterranean were studied. The absence of significant tides and the generally weak coastal currents restrict significant beach morphology changes to most important storm events but the variability of coastal evolution suggests the role of other factors. To assess these evolution parameters, the morphological characteristics of the beaches as well as the historical evolution of the shoreline were studied. This analysis, based on aerial photos and DGPS surveys, allowed highlighting the behavior of beaches over historical (1948-2012) period. For the historic scale, 15 beaches are considered to be in erosion, 16 are stable, the others show shoreline progression. The historic analysis, through several periods of time, shows that beaches are in perpetual movement. Moreover, some periods are particularly erosive (i.e. 1996 to 2002) for a number of beaches. Several parameters must be considered to explain the beach behavior changes as: beach orientation, closure, geology, hydro-climatic regime, grain size and length. The wave backward modeling ANEMOC was used to analyze wave characteristics and the occurrence and direction of the most important storm events. The entire dataset was used to obtain a conceptual model describing the most important factors involved in the contrasted observed coastal evolution: symmetric or asymmetric beach rotation, homogeneous retreat or progradation and rapid shoreline movements due to the presence of beach-cast Posidonia Oceanica seagrass litter.
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Dates et versions

hal-00925014 , version 1 (31-01-2014)

Identifiants

Citer

Yann Balouin, Rémi Belon, Anne Merour, Camille Riotte. Evolution of Corsican pocket beaches. Journal of Coastal Research, 2014, Journal of Coastal Research - Special Issue 66, 66, pp.96-101. ⟨10.2112/SI70-017.1⟩. ⟨hal-00925014⟩

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