Erosion and deposition processes are usually described using empirical formulations developed under steady uniform flow conditions that are not well adapted to fast transient flows. Consequently, significant variations exist among the predictions of the morphological evolution in rivers.
Based on laboratory experiment, we investigate the flow behaviour and the development of the velocity profile to better characterise the bed shear stress responsible for erosion and deposition processes. Digital imagery techniques such as PIV are used, allowing for a detailed measurement of the velocities, both in the water and in the moving sediment layers.