Combining suspended sediment monitoring and fingerprinting to determine the spatial origin of fine sediment in a mountainous river catchment - Archive ouverte HAL Access content directly
Journal Articles Earth Surface Processes and Landforms Year : 2011

Combining suspended sediment monitoring and fingerprinting to determine the spatial origin of fine sediment in a mountainous river catchment

(1, 2) , (3, 4) , (1, 2) , (1, 2) , (3) , (3) , (1, 2) , (5) , (1, 2) , (3)
1
2
3
4
5

Abstract

An excess of fine sediment (grain size <2 mm) supply to rivers leads to reservoir siltation, water contamination and operational problems for hydroelectric power plants in many catchments of the world, such as in the French Alps. These problems are exacerbated in mountainous environments characterized by large sediment exports during very short periods. This study combined river flow records, sediment geochemistry and associated radionuclide concentrations as input properties to a Monte Carlo mixing model to quantify the contribution of different geologic sources to river sediment. Overall, between 2007 and 2009, erosion rates reached 249 ± 75 t km−2 yr−1 at the outlet of the Bléone catchment, but this mean value masked important spatial variations of erosion intensity within the catchment (85-5000 t km−2 yr−1). Quantifying the contribution of different potential sources to river sediment required the application of sediment fingerprinting using a Monte Carlo mixing model. This model allowed the specific contributions of different geological sub-types (i.e. black marls, marly limestones, conglomerates and Quaternary deposits) to be determined. Even though they generate locally very high erosion rates, black marls supplied only a minor fraction (5-20%) of the fine sediment collected on the riverbed in the vicinity of the 907 km2 catchment outlet. The bulk of sediment was provided by Quaternary deposits (21-66%), conglomerates (3-44%) and limestones (9-27%). Even though bioengineering works conducted currently to stabilize gullies in black marl terrains are undoubtedly useful to limit sediment supply to the Bléone river, erosion generated by other substrate sources dominated between 2007 and 2009 in this catchment.
Fichier principal
Vignette du fichier
Evrard_ESPL_2010_post-print.pdf (2.39 Mo) Télécharger le fichier
Origin : Files produced by the author(s)
Loading...

Dates and versions

insu-00648337 , version 1 (18-05-2020)

Identifiers

Cite

O. Evrard, O. Navratil, S. Ayrault, M. Ahmadi, J. Némery, et al.. Combining suspended sediment monitoring and fingerprinting to determine the spatial origin of fine sediment in a mountainous river catchment. Earth Surface Processes and Landforms, 2011, 36 (8), pp.1072-1089. ⟨10.1002/esp.2133⟩. ⟨insu-00648337⟩
291 View
122 Download

Altmetric

Share

Gmail Facebook Twitter LinkedIn More