LIFE Blue Belt: Fish pass documents submitted for Aschach

In mid-May 2026, VERBUND Hydro Power submitted official submission documents to the responsible authorities to set up a fish pass at the Aschach Danube power plant. Construction will start following approval, which is expected in 2027. For the first time, this project will make the Upper Austrian Danube fully passable to fish from its border with Bavaria.

"With the fish pass in Aschach, we are filling a last major void on the Upper Austrian Danube and creating consistent migration routes for numerous fish species," explains Christian Freiler, head of the Upper Danube plant groups at VERBUND.

Project overview

The European Union’s LIFE Blue Belt Danube Inn project is creating a bypass channel in the vicinity of the power plant in Aschach that will have to be technically constructed to a large extent due to limited space. Once completed, continuity for migrating fish species will be restored for another section of the Danube, and a contribution will be made to strengthen biodiversity in the Danube-Inn River corridor.

VERBUND Project Manager Hannes Einbild commented: "The combination of the vertical slot fishway, fish ladder and near-natural bypass stream makes it possible to overcome the extraordinary water level efficiently and in a manner appropriate for the fish. A particular challenge was the large amount of compensation water of up to 8 m3/s required during planning, as it was almost impossible to adapt the flow in the fish pass to the needs of the fish."

The fish pass has a total length of around 1.8 kilometres and consists of vertical slot fishways with a length of around 765 metres, a rectangular channel of around 450 metres, an asymmetric fish ladder of around 285 metres, and a semi-natural bypass of around 303 metres. This makes it possible for a run-of-river power plant to overcome the very high impounding depth of 15 metres as effectively as possible.

Ecological importance

Thanks to the corridor effect of the LIFE Blue Belt, free fish migration will again connect important spawning and nursery habitats along the Danube. This will also improve living conditions for gravel- and flow-loving species.

About LIFE Blue Belt Danube Inn

The planned LIFE project aims to link valuable Inn River and Danube habitats and improve habitat conditions within the Natura 2000 sites. The benefits of LIFE Blue Belt Danube Inn for the Inn River and Danube ecology range from combining existing habitats to creating new habitats: LIFE Blue Belt Danube Inn