Preparation for construction of the fish bypass at the Abwinden-Asten power plant
As part of the LIFE+ Network Danube project, it will become possible for fish to avoid the Abwinden-Asten power plant with the construction of Austria’s longest fish bypass.
The Danube power plant Abwinden-Asten is the third hydropower plant on the Danube in Austria to become barrier-free. Initial construction preparations, such as clearing activities in the floodplain forest, will start in 2019. The natural bypass stream will be constructed in the municipality of Luftenberg to the south of the Danube. In the future, fish will have more than five kilometres of new habitat and the opportunity to bypass the power plant. In total, about five hectares of new river habitats will be created. Investment in the measures amounts to around €7 million. The work is scheduled to run until early 2020.
VERBUND, Austria’s biggest power company, is starting on preparations for the construction of the fish bypass at the Danube power plant Abwinden-Asten in 2019. The first clearing activities in the floodplain forest will start in mid-January 2019. Earthworks for the bypass stream will also start during the winter. The fish bypass will be completed in spring 2020.
Natural bypass stream
The natural bypass stream on the right bank of the Danube will be 5.3 kilometres in length. The intake structure, which is also the fish bypass exit point, is located in the Abwinden-Asten reservoir at current km 2,122.3 slightly upstream of the Ausee, while the fish bypass flows back into the Danube 700 metres below the VERBUND power plant Abwinden-Asten at current km 2,118.9.
The Mitterwasser is also benefiting from the project, as measures are also being implemented in the area of the power plant access road.
Project leader David Oberlerchner says, “The channel will have a natural design. Valuable habitats and reproduction sites for fish will be created on the gravelly banks. The water flow rate for the fish bypass is a minimum of 2 m³/s and rises to up to 9 m³/s. By comparison, the Ipfbach has an average water flow rate of 0.9 m³/s.”
The project will combine the storage areas of Wallsee-Mitterkirchen and Abwinden-Asten and their tributaries such as the Traun.
Project data of the Abwinden-Asten fish bypass
Capacity 4,000 l/s, up to 9,000 l/s at higher Danube flow rates
Length approx. 5.3 km
Height difference 10.7 m (at low water)
Gradient 2 per thousand
Planning EZB TB Eberstaller & TB Zauner, DonauConsult
Fish bypass 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 a few 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.
LIFE+ project “Network Danube”
The entire Life+ “Network Danube” project is financed by six financing partners (EU, Federal Ministry of Sustainability and Tourism, provincial governments of Upper Austria and Lower Austria, Regional Fishing Associations of Upper Austria and Lower Austria). The objective is to improve the fish fauna of four Natura 2000 areas and of tributary systems.
More about the project: www.life-netzwerk-donau.at