Kokkasaari, Salmonid habitat restoration on the River Vuoksi

Located in the River Vuoksi, Kokkasaari is a small islet formed as a result of the dredging of rocks. Environmental restoration by shaping and lowering the islet aims at improving the area as an underwater breeding and living habitat for fish.


The Kokkasaari salmonid habitat restoration work, a joint project of the City of Imatra, the ELY Centre for Southeast Finland, and Fortum, got under way in June 2020. The work started with establishing a temporary service road and removing trees from the small islet, to provide access for the work equipment.

Next, spawning gravel was transferred to the work site and then the dismantling of Kokkasaari islet began. The islet consisting mostly of dredged rocks was lowered to enable water to flow over it. Extra rocks were moved in front of the islet and to the main channel side, and spawning gravel was spread between the rocks. The restoration project was completed in September 2020.

Smooth and tangible collaboration

The City of Imatra was responsible for the practical work of the restoration project, and the ELY Centre for Southeast Finland was monitoring the realisation of the project. The project was funded by Fortum and the ELY Centre for Southwest Finland.

”The aim of the Kokkasaari restoration work is to increase the habitat area suitable for the different stages of the salmonid life cycle. The cooperation has once again gone really well. The shared goal and working together will produce tangible measures and results on the River Vuoksi,” says Tomi Menna, Fishing Master, City of Imatra.

Fortum, the City of Imatra, and the ELY Centre for Southeast Finland have been carrying out fish habitat restorations at River Vuoksi since 2013. Previous works have taken place in the stretch between the Tainionkoski power plant and the City of Imatra, and off Mellonlahti bay, about one kilometre from Kokkasaari.