Fish protection and inflow at hydropower plants with low head

Protection of downstream migrating fish at hydropower plants has gained importance in recent years. To meet the ecological requirements of the European Water Framework Directive, the safe downstream passage has to be ensured by providing an adequate migration corridor for fish in case new hydropower plants are constructed as well as existing hydropower plants are refurbished. However, for an accurate evaluation of fish protection systems, the requisite hydraulic background is still missing. Addressing this gap, these fundamentals were investigated in the research project presented in this article utilizing both numerical modelling and physical scale model tests and evaluated regarding the fish behaviour and the effects on the efficiency of the turbines. Moreover, the impact of the turbine passage on fish at hydropower plants with low head were examined with state-of-the-art methods. The information gained in this study provides the knowledge to derive recommendations for a more efficient and sustainable expansion of hydropower in the future.