ABSTRACT
Fish passes along river Meuse between French border and the city of Namur in Belgium need to be modernized. The existing fish passes have too low attraction discharge and too small pools for large migratory fishes. Additionally, their entrance needs to be moved as a consequence of implanting new hydropower plants. Due to space constraints, the new fish passes need to be rebuilt in the existing fish pass gutter. This results in a quite complex hydraulic design. A vertical slot fish pass is located in the downstream part of the existing gutter. A pressurized duct provides an additional discharge for fish attractiveness at the pass entrance. Due to this complexity, the fish pass was investigated through both numerical and physical modeling. A physical model at scale 1:5 of the whole pass helped to investigate the flow details and to optimize geometries. Numerical modeling focused on the free surface flow in the pass pools.
