Raasakka’s Fishheart fishway

The hydraulic Fishheart fishway in Raasakka on the Iijoki River supports Pohjolan Voima's efforts to promote biodiversity. The restoration of migratory fish and hydropower production can be reconciled.

Fishheart will be in use in Raasakka from 2023 to 2025. Valuable research data will be obtained on its functionality, as the Finnish innovation Fishheart is now being used for the first time at the lowest power plant on a river flowing into the sea, where, for example, salmon can ascend directly from the sea. This research data will help develop various migratory fish solutions and their compatibility in the future.

The Fisheart fishway will be removed from the river for the winter.

Fishheart fish counter statistics for the year 2024.

Diagram shows the total number of fish in the Fishheart during June – September.

Fishheart fishway in operation at Raasakka power plant

The goal of the broad-based cooperation is to develop the natural cycle of migratory fish through:

An assisted natural cycle of migratory fish has already been created in the Iijoki river as a result of the cooperation. The lowermost power plant at Raasakka has a Fishheart fishway that boosts upstream migration, and the uppermost power plant at Haapakoski has Finland’s first downstream migration route for migratory fish fry. With their help, fish and fry can be transported past power plants.
By researching and developing the impacts, it is possible to obtain valuable research data and more information to be used when building the next bypass routes.
The development of the migratory fish population is supported by the planting of eggs and juveniles, as well as transfers past the power plants.
In Raasakka, there are several options for upstream migration. As part of the overall project, we are gaining experience with the functionality of the Fishheart fishway in Raasakka. n addition, the possibilities of using an old riverbed as a migration route and breeding area for migratory fish are being developed and modelled in cooperation with other parties at Raasakka.
The ultimate solutions are being discussed with stakeholders.

Operating principle of the Fishheart fishway

Flow guides fish to Fishheart
The attraction flow of Fishheart guides fish to the mouth of Fishheart. The location of Fishheart near the power plant can be changed and optimized based on observations and experiences.

Artificial intelligence identifies fish
Intelligent equipment with cameras identifies the fish that have swum into Fishheart. Real-time data is collected on the number and species of fish.

Fish move over the dam
In Fishheart, fish move hydraulically through the pipeline over the dam to the upper reservoir without injury. Some are transferred to a container and further to the upper part of Haapakoski to continue their migration.