The Suomunjoki, a nine-kilometre river in the Koitajoki watershed, has undergone a significant restoration project led by the Snowchange Cooperative. Meandering through the old growth forests of Patvinsuo National Park, Suomunjoki has long been considered a diamond of the Koitere Lake Basin because of its natural beauty. Unfortunately, dams constructed in the early twentieth century have altered the natural flow of the river and blocked the migration of several fish species. This is the first time that a civil society organisation has undertaken a restoration project on public lands in Finland, marking a significant milestone for the country.
Based on oral histories, place names and archaeological data, the very first inhabitants of Suomujoki were the Indigenous Sámi peoples. By the 1500s the Karelians and Eastern Finnish wilderness communities used the lake as a seasonal fishery and hunting area. While this 9-kilometer-long river has remained relatively intact, in the latter part of 1900s a dam was constructed to enable timber to float downstream to Lake Koitere from Lake Suomu, preventing fish such as common dace, grayling and brown trout from migrating to their spawning grounds.
Photo: Snowchange.
After lengthy discussions between Parks & Wildlife Finland and Snowchange Cooperative – the organisation implementing the Koitajoki project in Eastern Finland – an agreement was signed in Autumn 2023 to enable a civil society organisation to restore public lands inside a national park. “This is a first for Finland” says Tero Mustonen, President and Founder of Snowchange Cooperative. “The dam at Suomunjoki had been a target of several priority lists in the region to be addressed, but no action had been taken before.”
In Autumn 2023, a small brown trout population was also discovered in the river. “Brown trout in the Koitajoki basin are extremely endangered,” says Mustonen. “It is important that we restore and protect the habitats for these fish, and in particular remove blockages which prevent their migration to their spawning grounds.”
Restoration work on the river began in December 2023, with 14 square meters of rocks installed to “bury” the wall of the timber floating dam to enable connectivity. Later in the year hydrological restoration of the stream downstream from the dam was carried out. “We reinstalled all of the large boulders and rocks in the stream, and also added gravel to rebuild the salmonid spawning beds,” Mustonen explains. This work helped to restore approximately 12 spawning areas, and additional work was carried out to provide habitat for juvenile fish in side streams.
The restoration work was completed in July with support from the River Guardians of Koitajoki. This included creating habitats for fish and insects and adding deadwood for ecological productivity. “Working together with local helpers and operators the former dam environment was brought to its final form – the first ever such operation in Finland in a national park by an NGO,” says Mustonen.
For the first time in 50 years, the surviving grayling and trout populations have access upstream and downstream in the Suomunjoki, with common dace, crayfish and other species also benefitting from the restoration work. “Before the 1950s, the Koitajoki region was famous for its trout, land-locked Atlantic Salmon and grayling populations,” says Mustonen. “Rapid build-up of hydropower cut the migratory pathways of many of these salmonids. In the subsequent years when the Finnish wilderness areas were utilised for a large-scale forestry activity the hydrological and aquatic habitats suffered further.”
Timber floating cleared rapids and spawning areas, altered hydrological conditions and peatlands were replaced with tree plantations. Lake Koitere has also been heavily regulated by the Pamilo hydropower plant. “This eliminated the natural hydrological cycle of the lake,” Mustonen explains. “From the 1990s, the lake where the Suomunjoki trout could go to feed was stocked with large amounts of pikeperch, increasing predation on the lake. Thus, the small population of trout that has survived in Suomunjoki is exceptionally important for genetic and ecological preservation.”
Photo: Snowchange.
In June 2024 Thomas Miller, one of the artists in residence at the the Koitajoki project, visited the site and filmed the restoration work taking place. His film, which will be screened at the Festival of Northern Fishing Traditions this September, will include reflections on his experience in the Koitajoki landscape.
To find out more about the Koitajoki Watershed project, visit their project page.
