In 1909, Sofieholm’s hydroelectric power station, located at Nianån’s outlet in the Bothnian Sea, was built to secure the electricity supply to a textile factory. At that time, the plant was important for the electrification and industrialization of the village.

Today, on the other hand, electricity production is of less importance, both from a national and local perspective. Therefore, in 2017, the Municipality of Hudiksvall chose to buy the power plant for 800,000 Euro and remove it (300,000). The financiers of the project were: Hudiksvall Municipality, Swedish Environmental Protection Agency, Swedish Agency for Marine and Water Management and the Swedish Anglers Association.

The 2 m high dam that led water in a 250 m long tube to the powerplant was removed and the water was reintroduced to its natural stretch. In connection with the power plant being shut down, a reservoir dam located 20 km higher up in the system could also be removed and replaced with a level holding threshold.

After more than 100 years of access to only 80 m of the river, the work has opened up 90 km of stream water habitat for fish including tributaries and recreated the natural flow regime in the water system. 

The purpose of the project was to restore previously damaged water biotopes and to promote the biological diversity of the water system. Furthermore, the municipality considers that the work has created an attractive and sustainable living environment that contributes to rural development. 

The site of the old dam will be protected from future exploitation by establishing a nature reserve. 

Target species: 

Brown trout (Salmo trutta) 

Pearl mussel (Margaritifera margaritifera) 

Lamprey (Lampetra fluviatilis)

European eel (Anguilla anguilla)

Post removal

The project team have been monitoring the following:

-Fish ((migration with up- and downstream traps, telemetry and pit-tags) community composition with electrofishing)

-Benthic fauna

– Flow regimes

– Habitat mapping

-Holistic evaluations (Stable isotopes and system metabolism)

The results are not yet evaluated but we have seen that the fish are back and were moving past the former dam the first fall.

Thank you Johan Andreasson for providing the information on this case study along with the photographs. 

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