The Kuusinkijoki dam removal project, one of Finland's most significant efforts to restore free-flowing river kilometres, aims to protect the endangered native brown trout population.
The Kuusinkijoki dam removal project is set to become one of the most significant dam removal efforts in Finland, offering the most extensive restoration of free-flowing river kilometres in the country. This initiative aims to protect the endangered native brown trout population, renowned for its exceptionally large specimens, which has long attracted fishermen to the River Kuusinkijoki. Scientists believe that removing the dam is the only viable solution to preserve this unique trout population, as it will reopen upstream habitats and eliminate the disruptive hydropeaking problem currently impacting the trout’s spawning success downstream.
| Project status | Completed |
|---|---|
| Project type | Dam removal: demolition |
| Country | Finland |
| River | Kuusinkijoki Piilijoki (Kuusinki River) |
| Removal date | Early 2025 |
| Km to be opened | 412 km |
| Focal species | Salmon, whitefish and others |
| Organisation | Kuusinkijoki kuntoon ry |
| Project website | Kuusinkijoki.fi |
The removal of the dam at the original Piilijoki stretch will restore uninterrupted fish migration routes, allowing smolt to migrate downstream in the spring and adult trout to move upstream in late summer when water levels are low. This project also includes halting the operations of a large hydroelectric power plant, which will end the hydropeaking that has been detrimental to fish reproduction and overall riverine biodiversity downstream. By redirecting all water to the natural Piilijoki arm, the river’s ecological health is expected to improve significantly, benefiting various species and restoring the river’s natural dynamics.
The primary goal of the Kuusinkijoki dam removal is to restore the river’s ecological status from good to excellent by reopening the Piilijoki habitat, which has been dry for a century. The project will open up over 400 km upstream and create a 1.4 km long white water rapid with an 11-meter height drop, providing critical habitat for riverine species, including a vital spawning ground for the brown trout. While no significant negative effects have been identified, the water permit process will address any concerns that may arise, ensuring the project’s success in restoring the river’s natural environment.
The Kuusinkijoki kuntoon ry (Free Kuusinki Association) has successfully delivered the Opening Piilijoki project to restore the natural flow of the Piilijoki River. Supported by an Open Rivers Programme grant, the project’s central achievement is the removal of man-made barriers, including the decommissioning of the Myllykoski hydropower plant and the reopening of the old Piilijoki river basin. A new natural river channel has been established, creating vital spawning grounds for fish, including the critically endangered Kuusinkijoki brown trout.
Submerging weirs have been constructed to maintain upstream water levels while still allowing the free passage of aquatic species. The restoration work has already improved biodiversity, strengthened local ecosystems, and created better habitats for riverine plants and wildlife. These actions contribute to the long-term recovery of unique, river-specific brown trout populations within the Kuusinkijoki River basin.
Beyond its ecological gains, the project also supports nature tourism, enhancing both the environmental and economic value of the area. The Opening Piilijoki initiative demonstrates how community-led conservation can deliver tangible improvements to freshwater biodiversity and habitat restoration.
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