Funding body

Austrian Research Promotion Agency (FFG)

Project coordinator

• Prof. Dr.-Ing. habil. Markus Aufleger
  Department of Hydraulic Engineering, University of Innsbruck (UIBK)

Project partner

• Institute of Hydrobiology and Water Management (IHG), University of Natural Resources and Life Sciences, Vienna

• Albatros Engineering GmbH, Herzogsdorf

• IUS Weibel & Ness GmbH

Employees (AB Wasserbau, UIBK)

• Prof. Dr.-Ing. habil. Markus Aufleger

• DI Ruben Tutzer

• DI Dr Barbara Brinkmeier

Project duration

• 03/2017 - 05/2019

Project description

Hydropower is a sustainable form of energy generation, but it can have negative ecological consequences. In this context, the possible loss of the longitudinal continuum or the continuity of the watercourses and the harmless passability of hydropower plants upstream and downstream should be mentioned in particular. The realisation of downstream, harmless fish passability at large hydropower plants is particularly difficult, as there are hardly any efficient solutions available to date. This problem prompted the Department of Hydraulic Engineering at the University of Innsbruck to develop the cable rake and subsequently to fundamentally develop the cable rake into an electric cable rake as a new, innovative fish protection concept.

The electric rope rake is a hybrid system that combines a mechanical barrier (rope rake) with a behavioural barrier (electric field). This integral concept achieves a controlled deterrent effect at the electric cable rake and at the same time the fish are guided towards the bypass by the orientation of the electric cable rake. The steel cables, which form the mechanical component of the hybrid system, serve as the anode and cathode around which the localised electric field is formed. The electrical voltage on the cables is in the low-voltage range and can be varied according to requirements.

The development of an electrified rope rake has the potential to

• to form the electric field required for scouring locally on the electric rope rake and thus achieve a controlled scouring reaction with a guiding effect by directing the rope rake towards the bypass,
• to create a previously impossible homogeneity of the scouring effect over the entire guiding plane,
• to significantly increase the clear distance between the horizontally tensioned ropes compared to a non-electrified rope screen with an unrestricted fish protection effect (i.e. considerable operational advantages, lower support forces, lower investment costs) and
• to create a very effective and cost-effective fish protection system that can be used in small, medium and large hydropower plants.

The effectiveness of the hybrid barrier in terms of fish protection and fish guidance is to be investigated using ethohydraulic tests at the test facility of the University of Natural Resources and Life Sciences in Lunz am See for various potamodromous fish species. The behaviour of the fish on the electric cable rake and differences between the species will also be determined using intensive video evaluations.

The aim of the project is to develop a cost-effective, widely applicable and highly efficient fish protection system and to answer important technical and behavioural questions. The possibilities as well as the limitations of the electric cable rake as a fish protection concept for ecologically adapted hydropower utilisation are to be clearly demonstrated.