Measures to Improve Fish Passage Through a Turbine

Abstract

This chapter focuses on the topic of measures to improve the fish passage through a turbine. Based on applications at the bulb units of the FIThydro Testcases of Guma, Bannwil and Obernach cost efficient and simple to apply measures are analysed. In the following two methods are presented. Applying a numerical analysis of the downstream fish passage typical physical stressor variables as strike, shear and barotrauma can be identified and correlated to the biological impact on the fish. In the FIThydro project, Voith applied the method to a wide range of operating conditions to derive fish-passage hill-charts. These allow a judgment of the physical impact on fish, dependent on the operating condition of the turbine. The studies at the Obernach lab performed by the team of the Technical University of Munich, show another method to improve fish survival rates by influencing fish pathways through the turbine. These promising results can be used for the Induced Drift Application (IDA), which are described in detail.