The Dynamics of Suspended Sediment in a Typical Alpine Alluvial River Reach: Insight From a Seasonal Survey

Autor: Sébastien Zanker, N. Bodereau, N. Valsangkar, Clément Misset, Alain Poirel, Cédric Legout, Laurent Borgniet, Alain Recking
Přispěvatelé: UNIVERSITE GRENOBLE ALPES CNRS IRD GRENOBLE INP UMR IGE FRA, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Erosion torrentielle neige et avalanches (UR ETGR (ETNA)), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), METEO FRANCE UMR CNRM GAME CEN GRENOBLE FRA, Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), EDF (EDF), Laboratoire des EcoSystèmes et des Sociétés en Montagne (UR LESSEM), IRSTEA, Electricite de France, Université Grenoble Alpes (UGA), EDF - Division Technique Générale (DTG), Communauté des universités et établissements de Grenoble Alpes (ComUE Grenoble Alpes), Direction technique 'Géotechnique' (LCPC/DTGEO), Laboratoire Central des Ponts et Chaussées (LCPC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Water Resources Research
Water Resources Research, American Geophysical Union, 2019, 55 (12), pp.10918-10934. ⟨10.1029/2019wr025222⟩
Water Resources Research, American Geophysical Union, 2019, 55 (12), pp.10918-10934. ⟨10.1029/2019WR025222⟩
ISSN: 0043-1397
1944-7973
DOI: 10.1029/2019wr025222⟩
Popis: International audience; The transport of suspended sediment is associated with important social, economic, and environmental issues. It is still unclear, however, how suspended sediments eroded on hillslopes are transferred downstream through the river system. In this study, we aimed to investigate this process by applying a sediment budget approach to a typical 3.5-km-long Alpine braided reach. Using high-frequency suspended load measurements combined with Monte Carlo simulations for uncertainty propagation, we observed a significant buffering behavior of the reach studied. Thirty-two of the 48 events observed during the 2-month campaign showed significant differences between upstream and downstream mass transported as suspension, despite the reach studied was short compared to the upstream drainage area (130 km(2)). These differences at the event scale varied widely within an envelope comprised between a net erosion equivalent to 74% of upstream suspended mass and a net deposition equivalent to 71%. Budgets were found to be controlled at a nearly instantaneous time scale by the liquid discharges and the suspended sediment concentrations in an opposite way: for low upstream concentrations, net erosion increased when the discharges increased, while above a certain concentration, net deposition increased when the concentrations increased. Moreover, coarse particles mobility in the reach (characterized via bedload transport measurements) appeared to have a strong influence on the availability of suspended particles as both quantities evolved concomitantly through time. These observations have important implications for our understanding and modeling of the transfer of suspended particles in gravel bedded streams.
Databáze: OpenAIRE
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