Behaviour of fish in the sphere of the water inlet at the pumped storage hydropower plant Geesthacht

In order to assess the hazard for fish fauna of the river Elbe caused by the impacts of the pumped storage hydropower plant in Geesthacht, the behaviour of fishes in the near field of the water intake was analysed using a Dual Frequency Identification Sonar (Didson). Due to the recording it became apparent that fishes exceeding a length of 20 cm took refuge in case the pump-turbines where started and steered clear from the water intake and screens during operation. However fishes less than 20 cm did not stand the chance to escape and where pulled in by the current caused by the pump-turbines. Indeed while operated with short hydraulic circuits, fishes less than 20 cm avoided the area of water intake, resulting in a smaller risk of damage to the population.