GRAVITATION WATER VORTEX POWER PLANTS
Even back in 2006 and 2011 we could show by a dense screen fish barrier upstream, at our gravitation water vortex power plant (GWVPP) in Obergrafendorf in Lower Austria, that fish can go upstream through the hydropower plant. Fish of the Pielach River like Danube salmon, trout, aitel, grayling and bullhead could be stopped at the dense screen fish barrier.
In summer 2013 fish experts made a study with marked fish at our GWVPP in Obergrafendorf. The migration test was made with 60 various small, medium and large fish, like Danube salmon, aitel, trout and grayling, which were caught by electrical fishing at the Pielach River. Then all these fish were put into the bounded tail water of the GWVPP. Within 6 days around 30% of the fish had migrated upstream of the GWVPP.
Most of the fish upstream of the Zotlöterer-turbine was caught through electrical fishing.
And it was noticeable that only a few fish were caught at the professionally installed fish trap.
Then fish were documented by length, weight and with several photos.
Several fish like a Danube salmon, smaller and larger exemplars of brown trout, chube and grayling were documented.
When complete, the study showed also that fish move downstream through the GWVPP, because some of the fish that went upstream through the Zotlöterer-turbine could not be caught successfully, so these fish went dazed by the unsuccessful electrical fishing downstream thtrough the GWVPP. Then these dazed escapees (see the chube photo beside) were documented after being caught at the dense screen fish barrier downstream of the GWVPP. So the fish monitoring shows that several fish can migrate upstream and downstream a GWVPP.
A third study with a sensor fish, which passing through our GWVPP gives very low values
for fluctuation of water pressure,
and for rotation movement.
All these values are very low as you can see in the diagrams and so injury or a disorientation of fish during a migration through a GWVPP could be excluded. The rectangular marked area in the diagrams show the period of time when the sensor fish pass the rotation tank and the Zotlöterer-turbine at 5,5s on the time line.
All three studies with local fish, with marked and introduced fish and with the data of the sensor fish, give a high level of migration for different types and sizes of fish through a GWVPP. With GWVPP-technology injury of fish by enormous pressure, by fast running turbine blades and by a fine screen system, is only a relic of conventional hydro power plants.
Additional Information about fish migration through a GWVPP you will find at ecology.