Improvement of revitalization measures for enhancing fish migration

Abstract This research focuses on the verification of a nature-like fish pass in the Myjava River to facilitate fish migration by imitating natural environments. Utilizing the HEC-RAS 2D model, three proposed design alternatives were simulated to evaluate and improve water velocities, depths, and flooded width that were evaluated as insufficient during measurements provided by the Water Research Institute in Bratislava, Slovakia during fish pass monitoring. The study found that while boulders effectively influenced minimum water depths, they can also affect water velocities. A milder slope combined with perturbation boulders is an effective solution. The research recommended mathematical modeling tools to assess design alternatives before implementation, minimizing the economic costs associated with trial-and-error methods.