Variant proposal of the fish passage using technical and close to nature approach

Abstract

Passing barriers on streams is nowadays an important activity for the protection and restoration of water ecosystems, and one of the goals of the European Union in the field of water habitat protection, that means barriers on waterways should be made suitable for the migration of aquatic fauna. The design and hydraulic parameters of these structures are fundamental in their design process, determining the effectiveness of fish passes in facilitating safe and efficient fish migration. These parameters should consider the specific needs and behaviours of the target fish species. It should provide suitable water depths, velocities, and facilitate fish movement upstream or downstream. The choice between technical fish passes, such as slot pass, and nature-like ones, such as rock ramps, is crucial. The selection of the right type also depends on various factors including the topography, hydrology and the species of fish being targeted. However, it is easier to achieve the parameters by technical fish pass. The proposed fish pass and its parameters were simulated by 1D mathematical model HEC-RAS. It was very difficult to design and fulfil all parameters according to the legislation. For more accurate results is recommended use of 2D or 3D models, or physical models.