Estudo experimental do escoamento em um sistema de transposição de peixes do tipo ranhura vertical

Abstract

The Brazilian energy matrix is predominated by the production of hydroelectric energy, a source that causes modifications in the river’s natural flow leading to obstruction of fish migration. In order to mitigate these impacts, it is proposed to construct a mechanism of fish transposition (STP), which consists of a hydraulic structure allowing the animal to overcome the obstacle to migration by means of energy dissipation. In Brazil, the enormous diversity of fish species requires complex systems, which reduce selectivity, such as vertical slot type fishways. The main goal in this study was to evaluate the characteristics of the flow for a vertical slot fishway. For this purpose, a reduced model was build with a view to determine hydraulic parameters and later correlation with a 1:40 scale prototype. Tests related to depth, velocity and flow visualization were performed for inclinations of 1.5% and 3.0%. The obtained results were then compared to the ichthyofauna data available. It was noticed that for the suggested configuration, the fish would have difficulties to transpose the system, since the structure dissipated too much energy and the flow velocities were superior to those deemed acceptable for the studied physiology. Thus, it was possible to evaluate the importance of previously analyzing structure’s configuration before actual construction, so that hydraulic parameters are adequate for the fish that will use the system, not rendering it inefficient.