Given the need to re-establish the river continuum, which has been disrupted on numerous watercourses by the construction of water management structures, proper planning and implementation of river restoration works are vital to conserving biodiversity in river and riparian environments. As part of this project, we examined the MABA-type fish pass, a technical passage with vertical slots that has proven effective in the past. In the first phase of the research, we assessed the suitability of the TELEMAC-2D software tool by simulating the operation of a comparable fish pass at the Arto–Blanca hydroelectric power station and comparing the numerical model results with available measurements. To this end, we developed a depth-averaged two-dimensional hydraulic model of the structure in question. In the second phase, we applied the same approach to the hydraulic analysis of the conceptual design of the MABA‑type AOP. We investigated the influence of various physical and numerical parameters on the flow's hydraulic characteristics and assessed the design's suitability against the prescribed criteria. The results confirmed findings from existing studies that varying the roughness coefficient at the bed has no significant effect on hydraulic parameters. Conversely, the choice of computational grid has a significant influence on the position of the main flow, the simulation of weaker eddy zones, maximum velocities and the rate of dissipation of turbulent kinetic energy. Reducing the flow rate and the longitudinal slope also reduces flow velocities and dissipation within the chambers, whilst a moderate narrowing of the chambers is reflected primarily in a change in the flow pattern. The results of the hydraulic analysis confirm the suitability of the TELEMAC-2D model for analysing flow conditions in a AOP with vertical slots. However, for final validation and optimisation of the design, a comparison with measurements on a physical model or prototype is still required. The results presented also provide an important starting point for the further design and optimisation of the AOP under consideration.
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