Altenwörth gets Lower Austria's longest fish bypass

At a citizens' information event in the municipality of Kirchberg am Wagram, VERBUND officially presented the fish bypass and old course project to interested local residents for the first time. "It was important to us to personally inform our neighbours about the project at first hand," says project manager Hannes Einfalt. The natural bypass stream on the left bank of the Danube will be 12.5 kilometres in length. The excavated materials will be used in the area of the old river course. The bank will be made more fish-friendly with gravel fills. At the same time, flat areas allow bathing guests more convenient access to the water and improve the water quality. "We are taking this unique opportunity to create the broadest benefit possible with our project," says Hannes Einfalt. Costs are estimated at 7.5 million euros. In total, the work will involve the movement of 575,000 cubic metres of gravel and fine sediment. As the work is taking place on the floodplain and no lorries of excavated material leave the project area, the impact of traffic on the settlement area will remain minimal.

The project connects the Wachau with the storage areas of Greifenstein and Melk with their tributaries and with the Traisen. Austria's largest land restoration project at the mouth of the Traisen was only completed in 2016.

Constructed Wetland: Biotope for water cleaning

An artificial biotope is being constructed on the left bank of the old course. The idea behind this "constructed wetland" is that the water should clean itself. The excess quantity of nutrients is filtered out and reduced. This is intended to reduce the growth of algae to a natural level. A model for the water quality of the old course at the Danube power plant Greifenstein.

Natural bypass stream based on proven models

Experiences with the fish bypasses at Greifenstein and Ottensheim-Wilhering confirm the concept of a natural river for bypassing the power plant. The gentile incline and alternation of shallow and deep water zones, enriched with structures made from dead wood, forms an attractive habit for fish and other aquatic lifeforms. The nature world of the nearby floodplain forest conquers the fish bypass in no time at all, as investigations in Greifenstein and Ottensheim prove. There, after just three months in operation, 41 out of 50 species of Danube fish and large fish (catfish) up to a length of 1.65 metres have been spotted and thousands of fish counted.  

More information on the project: www.verbund.com/altenwoerth