Author(s): Florent Grattepanche; Guillaume Gomit; Damien Calluaud; Dominique Courret; Pierre Sagnes

Linked Author(s): Guillaume Gomit, Damien Calluaud

Keywords: Sediment transport; Spawning habitat; Laboratory experiments; Unsteady flow; Sediment remobilization; Ecohydraulics

Abstract: The construction of large dams has been demonstrated to disrupt the continuity of river sediments, resulting in a loss of gravel that is essential for the lithophilic spawning fishes, in particular salmonids. Sediment replenishment operations are implemented to restore suitable habitats, but their sustainability remains uncertain due to flow unsteadiness associated with dam management and natural floods. The prediction of the fate of these artificial sediment inputs is challenging due to the absence of unsteady-state sediment transport laws that govern such processes. In order to enhance comprehension of these dynamics, a laboratory-scale model reproducing the hydrodynamic and sedimentary conditions downstream of the Hautefage dam (Corrèze, France) was developed. The model is based on Froude and Shields similarity to investigate the influence of flood hydrographs on sediment remobilization and transport. Using advanced optical measurements, experimental investigations have revealed that the transient acceleration of flow during the rising limb of floods can result in substantial spikes of bed shear stress and sediment flux.

DOI: https://doi.org/10.64697/iahr.proc.ise2026.abs.225

Year: 2026