Breaching in a wave-dominated barrier spit: The trabucador bar (north-eastern spanish coast) |
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| Authors: | Agustín Snchez-Arcilla Jos A Jimnez |
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| Institution: | Agustín Sánchez-Arcilla,José A. Jiménez |
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| Abstract: | The Trabucador Bar is a barrier coast linking the main lobe of the Ebro Delta with its southern spit. This coastal stretch, which may be considered as a microtidal transgressive barrier, is the most vulnerable area of the deltaic coast to storm-induced geomorphologic changes. During the second week of October 1990 a severe storm affected the Ebro Delta causing serious erosion, in which the Trabucador Bar was one of the most damaged zones. A breach 800 m long and with a maximum depth of 0·4 m below the mean water level was created. During the breaching process approximately 70 000 m3 of sand were removed from the subaerial barrier in a few hours. Three factors are normally responsible for the loss of sediment, longshore transport gradient, offshore transport and overwash processes, most of the eroded sediment (60 000 m3) was transported towards the inner bay due to overwash processes. The post-storm recovery of the zone was slow and far from complete, as the breach remained a conduit for onshore sediment transport under a regime of breaking and reforming waves. An artificial dune was subsequently constructed to close the breach and thus allow beachface recovery. |
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| Keywords: | Overwash processes Barrier coasts Breaching Storm effects Coastal erosion Ebro Delta |
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