Entrance to the fishway at HPP Altheim

At the hydropower plant Altheim in Germany different measures for improving the habitat availability in the fish pass are currently being implemented.

Fish passes as migration pathways and fish habitat

The hydropower plant Altheim has a 3.6 km long nature-like fish pass. Fish use the fish pass for upstream migration, enabling them to overcome the seven meter height difference from the downstream to the upstream section of the river. The fish pass not only functions as a migration pathway, but can also offer valuable habitats for different fish species and life stages.

Overview of the fish pass at HPP Altheim
Carrying out structural improvements in the fish pass

As part of the FIThydro work, Uniper is placing diverse structural elements such as ravines, deadwood and gravel areas in the nature-like fish pass. “The structures will help to improve the habitat availability by varying flow velocities, providing spawning grounds and juvenile habitats as well as protection from flood events and from predators,” explains Cornelia Felber from Uniper.

Over the next months, the structures will be monitored and evaluated according to their impact on the ecological improvement and their maintenance needs. These findings will help to maximize the ecological benefits of fish passes while also taking the interests of operators and residents into account.

New habitats are created by adding gravel to specific sections of the fish pass and strones are inserted into the stream to create flow variations.

You can find more information and pictures on the field work in Altheim on the Altheim Test Case site.

Lea Berg (TUM)
Picture rights: Uniper