Pertinence et pérennité de la restauration de chenaux latéraux : modèles issus de 15 ans de suivi sur le Rhône

Abstract : Numerous projects of side channel restoration have been implemented during the last decades to improve the ecological functioning of highly regulated rivers. Feedbacks regarding the hydromorphological adjustment of restored channels are rare or not shared. Nevertheless, such information is crucial to improve the design of restoration measures and to assess their sustainability. In this paper, we report an overview of results derived from the monitoring of 18 restored side channels conducted over more than 15 years in the Rhône River. Firstly, hydromorphological adjustments of restored channels (bed material grain size longitudinal patterns, dynamics of fine sediment accumulation) are described. Then, an assessment of the potential persistence of channels as aquatic habitats is conducted using trend models. Our results suggest that side channel restoration can be a relevant and sustainable measure in the context of the Rhone River. We also demonstrate that grain size conditions and fine sediment accumulation rates can be successfully predicted using simple metrics reflecting the hydrodynamic functioning of side channels, that managers can target or modify: the frequency and magnitude (i.e. maximum shear stress) of upstream overflow events and the maximum intensity of backflow events (i.e. maximum backflow capacity). These empirical relationships are important operational tools for guiding future project design in the Rhone River and potentially elsewhere. They can be used to predict the effects and the sustainability of side channel restoration. They may reduce the uncertainty about the potential hydromorphological adjustments of side channels after restoration, and contribute to optimize the balance between local ecological gains and restoration costs.
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Journal articles
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https://hal.archives-ouvertes.fr/hal-02042601
Contributor : Jérémie Riquier <>
Submitted on : Wednesday, February 20, 2019 - 2:49:38 PM
Last modification on : Wednesday, August 14, 2019 - 11:39:33 AM

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Jérémie Riquier, Hervé Piégay, Nicolas Lamouroux, Lise Vaudor. Pertinence et pérennité de la restauration de chenaux latéraux : modèles issus de 15 ans de suivi sur le Rhône. La Houille Blanche - Revue internationale de l'eau, EDP Sciences, 2019, p. 101-108. ⟨10.1051/lhb/2019020⟩. ⟨hal-02042601⟩

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