Fish ahoy

We at Hydroconnect take the concerns and questions of fishermen and environmental protectionists seriously. Therefore, we welcome an active dialogue in the interest of an environmentally friendly, sustainable solution for humanity, energy and the environment.

Questions and answers concerning fish migration and the environment.

Each location is planned separately, and the machine size is defined according to financial and ecological criteria. Drum diameters of up to four metres are possible. Hence, this system provides up to ca. 2 metres of space (in both directions) for the predominant fish species. The screw diameter is oriented in any case around the predominant fish in the waters in order to comply with the EU Water Framework Directive (WFD 2000/60/EC).
Yes, of course. All research programmes and monitoring studies were accompanied by the Institute for Hydrobiology and Water Management (HG) at the University of Natural Resources in Vienna (BOKU). 100% freedom from injury was confirmed by BOKU in numerous studies.
Through an additional EU patent, the specially shaped double screw in the fish entry, the adapted speed of the system as well as the shape of the shell as a gap-free drum guarantee that the hydrodynamic screw with double rotating cylinders will provide 100% freedom from injury for all water life. This was confirmed by studies conducted by the University of Natural Resources in Vienna (BOKU).
No, the hydrodynamic screw with double rotating cylinders is for the passage of the strongest and weakest swimming species of fish at all stages of life. For more details, go to “Studies“.
Not only the headrace water outflow from the ascent screw but also, and above all, the central luring current that is generated by the special shape and placement of the blades in the entry area (“double screw”) serve as a guiding current.
Fish swim actively against the current into the screw and are transported gently to the headwater. For outward migration, fish and microorganisms simply swim (drift) downstream with the headrace water. At many (large) locations, an additional luring current can make it easier to find.
No. The lower screw area is designed and patented so that it creates a luring current for fish and water life. That way the fish find the way via the fish ladder without being forced to do so.
There is a current leading to the screw in the bottom area of the entry, which is very well suited for fish and pentos that are weakened from swimming. (Also see Technology)
Each individual fish is released into a calm zone close to the bank by means of a “fish discharge chute” (discharge of the ascended fish with a marginal slope) over the dam, protection and coarse screen. The fish continue their migration after an orientation phase.
No. It is now possible for fish to pass transverse structures voluntarily, stress-free and injury-free and to move effortlessly upstream or downstream. The natural ecological balance ensures that the fish population remains constant or rather that the populations recover again if fish can reach their spawning grounds, winter habitats and other important habitats at any time. Therefore the river life is once again autonomous and hence the biodiversity is promoted.
Even in floods, fish are not simply swept away, rather the population normalises again after a short amount of time. Fish that are swept away in a flood can return to their original locations at any time. That way the population can recover again quickly.
More than 4000 hydropower plants in Austria’s rivers have no, or non-functioning fish bypasses. Altogether, according to the ministry, there are 33,000 migration obstacles in Austria alone due to transverse structures. They must be made passable in accordance with the EU Water Framework Directive in the interest of providing environmental protection for fish. Some of these locations have energy production potential, which can be converted into valuable electricity with the HYDROCONNECT system.