Characterization of the sediment properties, equilibrium suspension in the water column, and exchanges with the bed

Assessing the physical properties of sediments in suspension or deposited remains a difficult task due to the high temporal and spatial variability of the sediment origin, the flow regimes and extremely wide GSD observed both in the suspension and in the gravel bed. Moreover, the propensity of fine particles to flocculate biases all analyses made a posteriori on samples since the turbulence level is very different from the river environment (Droppo et al., 2015). In order to characterize the main parameters used in numerical models, often based on theoretical framework and empirical parameters, there is a strong need to improve our knowledge of the processes occurring at the local scale (particularly acting at the river bed interface), i.e. to better evaluate deposition and erosion terms classically implemented in numerical models but also infiltration and resuspension capabilities.

This workpackage is divided into 3 main subtasks:

1.1. In situ measurements of deposition and erosion parameters

1.2. Fine sediment fluxes

1.3. Exchange with the coarse matrix and 1DV modelling