Assessment of the Attractiveness and Passage Efficiency of Different Fish Passage Solutions at a Hydropower Plant by Combining Fine Scale 2D-Telemetry and Hydraulic Numerical Modelling

• Published in: Environments
• Main Authors: Séverine Renardy, Utashi D. Ciraane, Jean-Philippe Benitez, Arnaud Dierckx, Justine Gelder, Ana T. Silva, Pierre Archambeau, Benjamin Dewals, Michel Pirotton, Sébastien Erpicum, Michaël Ovidio
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2023
• Subjects: nature-like fishway; Archimedes screw; etho-hydraulics; hydrodynamic modelling; behaviour; Environmental technology. Sanitary engineering; TD1-1066; Weir; Atlantic salmon; Salmo salar
• Online Access: https://doi.org/10.3390/environments10070107; https://doaj.org/article/b4017b89a7054df19ac2a79dd1897a1c

Mitigation measures for downstream-migrating Atlantic salmon smolts ( Salmo salar L.) are commonly insufficiently attractive to enable safe entrance and passage with no delay. Combining 2D telemetry with hydrodynamic modelling has been shown to be a good tool to better understand the influence of hydrodynamic factors on the migration route choice of fishes. In this study, we investigated the smolt downstream migration at a hydropower plant in Belgium that offers five migration routes, including two Archimedes screws and one nature-like fishway. At the hydropower plant, the Archimedes screws were the most used migration routes, due to higher discharges and more important water depths at their entrance. The weir and the canal intake were less used by the smolts. The nature-like fishway turned out to be less used, with 23% of the smolts. Its associated crossing time was significantly longer, probably due to shallow water depths and high flow velocities. The nature-like fishway had the potential to become a good migration route for salmon smolts after improvements to increase attractiveness and passage efficiency. Moreover, the Archimedes screws were not detrimental to the smolts and did not cause any significant delays to the crossing time.