Duvert C. auteur aut IRD Gratiot Nicolas auteur aut IRD Anguiano-Valencia R. auteur aut IRD Nemery J. auteur aut IRD Mendoza M.E. auteur aut IRD Carlon-Allende T. auteur aut IRD Prat Christian auteur aut IRD Esteves Michel auteur aut IRD text journalArticle eng text/pdf born digital access In order to assess the extent of sediment connectivity between uplands and lowlands and to quantify the processes of in-channel deposition and remobilization, measurements of suspended sediment fluxes were conducted in a nested rural catchment of the Mexican Volcanic Belt. Data were collected over one year at three upland sites (3 to 12 km(2)) and two downstream stations (390-630 km(2)). Our results show that a structural discontinuity in the catchment (i.e. abrupt slope decrease at the junction between piedmonts and the alluvial plain from 2 to 10% to <0.1%) could be compensated by functional continuity during floods. Direct conveyance of fine sediment to the outlet occurred when a high stream transport capacity was reached. Erosion of the streambed was observed on various occasions and accounted for up to 50% of the flux leaving the catchment during one event. Conversely, temporary in-channel storage was apparent on other occasions, amounting to up to 52% of the flux recorded upstream during one storm. These two distinct behaviours were approximately equally distributed along the rainy season and strongly driven by the extent of coupling between surface and subsurface water. This work indeed highlights the role of baseflow spatial variations in determining the extent of lowland sediment conveyance. Riverbed erosional processes occurred when large differences in pre-event baseflow values (i.e. at least a twofold longitudinal increase) were observed between the 5-km distant lowland stations. Our findings outline the importance of systematically taking into consideration the baseflow parameter in research focusing on fine sediment transport across scales. specialized Deposition Erosion Longitudinal decoupling Mesoscale catchment Suspended sediment yield Tropical rain regime 062 87 1 129-140 2011 0341-8162 https://www.documentation.ird.fr/hor/fdi:010053732 10.1016/j.catena.2011.05.021 0341-8162 [F B010053732] https://www.documentation.ird.fr/hor/fdi:010053732 https://www.documentation.ird.fr/intranet/publi/2011/08/010053732.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2011-09-01 2017-08-23 fdi:010053732 fre