Three-Dimensional Analysis of Flow Velocities through a Large Pool Fish Pass in the Trzebuńka Stream ^†

This paper presents the hydrodynamic parameter values of a large pool fish pass joined with block ramps in the Trzebuńka stream. The aim of this work is to evaluate the large pool fish pass patency in terms of fish and to answer the question of whether fish migration upstream is possible. The assessment of hydrodynamic parameters was carried out on the basis of water flow velocity measurements using a flow tracker device and by calculating the following parameters: Water depth, shear stresses, and Froude’s and Reynold’s numbers. Velocity measurements were carried out in 23–30 hydrometric points which were determined in each of the pools. A survey was done using the Topcon GTS-226 (Topcon Corporation, Tokyo, Japan) total station. The data were processed in order to obtain the results of hydrodynamic parameters prevailing in flowing water. The graphs were prepared using the Grapher 11 software, showing the distribution of individual hydrodynamic parameters for fish pass chambers and overflows in the fish passage. We concluded that the fish pass in Stróża was designed and constructed correctly. However, from a technical point of view, some deficiencies could be found.