A Physical and Hydraulic Model of a Technical Fish Pass

The paper describes research focused on the design of a technical vertical slot fish pass. Based on measurements of the depths and velocities conducted on a hydraulic model of a fish pass at the Water Research Institute Laboratory in Bratislava, a 2D model was developed using River2D software. The study specifically targeted the barbel and bream fish zones, which have the most stringent criteria for depth and velocity. The simulation model developed demonstrated a strong predictive capability, with the Mean Square Error root ranging from 0.147 to 0.177, and the Mean Absolute Error ranging from 0.125 to 0.155, depending on the fish zone. A comparison of the results obtained (the velocity field and depths) indicates that the 2D model is a reliable tool for future modifications of this type of fish pass, whether for adjustments in its geometry or subsidizing discharges into the fish pass. Additionally, the visualization of the simulated velocity field, which is a critical factor for upstream migration, can aid in identifying migration routes.