1. Channel response to sediment replenishment in a large gravel‐bed river: The case of the <scp>Saint‐Sauveur</scp> dam in the <scp>Buëch River</scp> ( <scp>Southern Alps</scp> , <scp>France</scp> )
- Author
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Guillaume Brousse, Guillaume Fantino, Gabriel Melun, Laurent Borgniet, Jean-René Malavoi, Frédéric Liébault, Remi Loire, Mélanie Bertrand, Gilles Arnaud-Fassetta, Pôle de recherche pour l'organisation et la diffusion de l'information géographique (PRODIG (UMR_8586 / UMR_D_215 / UM_115)), Université Paris 1 Panthéon-Sorbonne (UP1)-Institut de Recherche pour le Développement (IRD)-AgroParisTech-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Erosion torrentielle neige et avalanches (UR ETGR (ETNA)), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Agence Française pour la Biodiversité (AFB), EDF (EDF), GEOPEKA LYON 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), Laboratoire des EcoSystèmes et des Sociétés en Montagne (UR LESSEM), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Division Production Ingéniérie Hydraulique (EDF DPIH), GEOPEKA, Agence francaise pour la biodiversite, Electricite de France, and INTERREG Alpine Space HyMoCARES
- Subjects
sediment replenishment ,restoration ,010504 meteorology & atmospheric sciences ,0207 environmental engineering ,02 engineering and technology ,01 natural sciences ,braided river ,Environmental Chemistry ,River management ,[SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology ,020701 environmental engineering ,0105 earth and related environmental sciences ,General Environmental Science ,Water Science and Technology ,Hydrology ,geography ,geography.geographical_feature_category ,RIVIERE EN TRESSE ,Sediment ,SAINT ,6. Clean water ,[SDE]Environmental Sciences ,dam impact ,river management ,Geology ,Channel (geography) - Abstract
International audience; The Saint-Sauveur dam was built in 1992 in the middle section of the Buech River. Downstream of the dam, a channel incision by several meters was observed. A gravel replenishment operation was planned in order to restore the active channel. An equivalent of two times the mean annual bedload-transport capacity (43,500 m(3)) was replenished downstream of the dam in September 2016. The aim of this paper is to quantify morphological change associated with sediment remobilization in order to evaluate the efficiency of the restoration works. The monitoring was based on a combination of (a) change detection using sequential high-resolution digital elevation models (from airborne LiDAR data), (b) bedload tracing using active ultrahigh-frequency radio-frequency identification technology, and (c) complementary field surveys of channel grain-size distribution and morphology for bedload-transport computation. Field monitoring allows us to capture a net aggradation along a 2-km reach after the first post-replenishment flood. A sediment balance analysis was performed to back-calculate bedload supply coming from the sluicing operation during the flood. Although the sediment replenishment operation clearly had a positive impact on the morphological conditions of the starved river reach, the effective bedload supply from artificial berms (22,650 m(3)) was insufficient to initiate substantial channel shifting along the restored reach and a subsequent amplification of the sediment recharge. The combination of high-resolution topographic resurveys and sediment tracing was successful to evaluate the downstream propagation of sediment replenishment effects.
- Published
- 2019
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