Ben Slimane A. auteur aut IRD Raclot Damien auteur aut IRD Evrard O. auteur aut IRD Sanaa M. auteur aut IRD Lefevre I. auteur aut IRD Le Bissonnais Y. auteur aut IRD text journalArticle eng text/pdf born digital access Reservoir siltation because of water erosion is an important environmental issue in Mediterranean countries where storage of clear surface water is crucial for their economic and agricultural development. The high density of gully systems observed in Mediterranean regions raises the question of their contribution to reservoir siltation. In this context, this study quantified the absolute and relative contributions of rill/interrill and gully/channel erosion in sediment accumulation at the outlet of small Tunisian catchments (0·1-10 km2) during the last 15 years (1995-2010). To this end, a fingerprinting method based on measurements of caesium-137 and total organic carbon combined with long-term field monitoring of catchment sediment yield was applied to five catchments in order to cover the diversity of environmental conditions found along the Tunisian Ridge and in the Cape Bon region. Results showed the very large variability of erosion processes among the selected catchments, with rill/interrill erosion contributions to sediment accumulated in outlet reservoirs ranging from 20 to 80%. Overall, rill/interrill erosion was the dominant process controlling reservoir siltation in three catchments whereas gully/channel erosion dominated in the other two catchments. We identified the presence of marly gypsum substrates and the proportion of catchment surface covered by soil management/conservation measures as the main drivers of erosion process variability at the catchment scale. These results provided a sound basis to propose guidelines for erosion mitigation in these Mediterranean environments and suggested to apply models simulating both rill/interrill and gully/channel erosion in catchments of the region. specialized TUNISIE MEDITERRANEE 062 068 27 3 785–797 2016 1099-145X https://www.documentation.ird.fr/hor/fdi:010066399 1099-145X [F B010066399] https://www.documentation.ird.fr/hor/fdi:010066399 https://www.documentation.ird.fr/intranet/publi/depot/2016-04-08/010066399.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2016-02-23 2020-05-21 fdi:010066399 fre