Journal cover Journal topic
Climate of the Past An interactive open-access journal of the European Geosciences Union
Clim. Past, 13, 711-727, 2017
https://doi.org/10.5194/cp-13-711-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
19 Jun 2017
Extreme flood event reconstruction spanning the last century in the El Bibane Lagoon (southeastern Tunisia): a multi-proxy approach
Aida Affouri1,2, Laurent Dezileau2, and Nejib Kallel1 1Laboratoire Georessources, Matériaux, Environnements et changements globaux, LR13ES23 (GEOGLOB), Faculté des Sciences de Sfax, Université de Sfax, BP1171, Sfax 3000, Tunisia
2Geosciences Montpellier, CNRS/INSU, UMR5243, Université Montpellier, Montpellier, France
Abstract. Climate models project that rising atmospheric carbon dioxide concentrations will increase the frequency and the severity of some extreme weather events. The flood events represent a major risk for populations and infrastructures settled on coastal lowlands. Recent studies of lagoon sediments have enhanced our knowledge on extreme hydrological events such as palaeo-storms and on their relation with climate change over the last millennium. However, few studies have been undertaken to reconstruct past flood events from lagoon sediments. Here, the past flood activity was investigated using a multi-proxy approach combining sedimentological and geochemical analysis of surfaces sediments from a southeastern Tunisian catchment in order to trace the origin of sediment deposits in the El Bibane Lagoon. Three sediment sources were identified: marine, fluvial and aeolian. When applying this multi-proxy approach on core BL12-10, recovered from the El Bibane Lagoon, we can see that finer material, a high content of the clay and silt, and a high content of the elemental ratios (Fe ∕ Ca and Ti ∕ Ca) characterise the sedimentological signature of the palaeo-flood levels identified in the lagoonal sequence. For the last century, which is the period covered by the BL12-10 short core, three palaeo-flood events were identified. The age of these flood events have been determined by 210Pb and 137Cs chronology and give ages of AD 1995 ± 6, 1970 ± 9 and 1945 ± 9. These results show a good temporal correlation with historical flood events recorded in southern Tunisia in the last century (AD 1932, 1969, 1979 and 1995). Our finding suggests that reconstruction of the history of the hydrological extreme events during the upper Holocene is possible in this location through the use of the sedimentary archives.

Citation: Affouri, A., Dezileau, L., and Kallel, N.: Extreme flood event reconstruction spanning the last century in the El Bibane Lagoon (southeastern Tunisia): a multi-proxy approach, Clim. Past, 13, 711-727, https://doi.org/10.5194/cp-13-711-2017, 2017.
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Short summary
The past flood activity was investigated using a sedimentological and geochemical analysis of surfaces sediments from a southeastern Tunisian catchment in order to trace the origin of sediments deposit in the El Bibane Lagoon. Aeolian, fluvial and marine source. This multi-proxy analysis on the BL12-10 core shows that finer material, a high content of clay and silt, and a high content of the elemental ratios Fe / Ca and Ti / Ca characterise the sedimentological signature of palaeo-flood levels.
The past flood activity was investigated using a sedimentological and geochemical analysis of...
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