Baseflow control on sediment flux connectivity: Insights from a nested catchment study in Central Mexico
Por:
Duvert C., Gratiot N., Anguiano-Valencia R., Némery J., Mendoza M.E., Carlón-Allende T., Prat C., Esteves M.
Publicada:
1 oct 2011
Categoría:
Earth-Surface Processes
Resumen:
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 12km2) and two downstream stations (390-630km2). 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. © 2011 Elsevier B.V.
Filiaciones:
Duvert C.:
IRD/Université Grenoble 1/CNRS, Laboratoire d'étude des Transferts en Hydrologie et Environnement UMR 5564, Grenoble, France
Gratiot N.:
IRD/Université Grenoble 1/CNRS, Laboratoire d'étude des Transferts en Hydrologie et Environnement UMR 5564, Grenoble, France
Anguiano-Valencia R.:
Facultad de Ingeniería Civil, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mexico
Némery J.:
G-INP/Université Grenoble 1, Laboratoire d'étude des Transferts en Hydrologie et Environnement UMR 5564, Grenoble, France
Mendoza M.E.:
Univ Nacl Autonoma Mexico, CIGA, Morelia, Michoacan, Mexico
Carlón-Allende T.:
Univ Nacl Autonoma Mexico, CIGA, Morelia, Michoacan, Mexico
Prat C.:
IRD/Université Grenoble 1/CNRS, Laboratoire d'étude des Transferts en Hydrologie et Environnement UMR 5564, Grenoble, France
Esteves M.:
IRD/Université Grenoble 1/CNRS, Laboratoire d'étude des Transferts en Hydrologie et Environnement UMR 5564, Grenoble, France
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