How are the water velocity and depth used by young Atlantic salmons to cross a hydropower plant?

In this study, we investigate two main components of the river discharge : the velocity and the water depth to understand their use by smolts at hydroelectric facilities. Six releases of 6 smolts each were monitored using 2D radio telemetry and the flow characteristics they encountered were numerically modelled in 2D. The comparison of the water velocities and the water depths (water columns) used by the smolts with the availability of these 2 variables in the flow shows that: smolts prefer high velocities and they mainly use the most available water depth while avoiding extreme values (lowest and highest depths). These results pave the way for an in-depth exploration of these two variables on the downstream migration routes equipping hydropower facilities.