How Finland is protecting its waters and restoring nature
- Restauration de la nature
Finland, famously known as the "Land of a Thousand Lakes," actually boasts over 160,000 lakes that form a breathtaking landscape of blue waters, lush forests, and diverse ecosystems. At the heart of Finnish surface water management lies a deep national commitment to preserving these waters—keeping them clean and thriving for both biodiversity and human enjoyment.
These recent projects illustrate Finland's proactive approach to protecting its national treasure.
Freeing rivers and reviving fish populations
Töllinkoski rapids in Lohja, Finland, flows freely again, thanks to a recently completed restoration project.
The Töllinkoski dam was in poor condition and its maintenance had become difficult. The removal of the dam has allowed the river to flow naturally, restoring habitats for endangered migratory fish.
The Töllinkoski dam in Lohja had started to deteriorate, and its maintenance had become difficult. Removing the dam and restoring the rapids turned the Pusulanjoki, Nummenjoki, Lake Lohjanjärvi, and Lake Hiidenvesi into one connected route for migrating fish.
Lauri Harilainen, a water resources engineer and co-founder of Watec Consulting Oy, has dedicated his career to protecting Finland's waters. He is particularly pleased when old dams, that form migration barriers for fish and aquatic life, are removed, and underwater cameras show migratory fish returning to their traditional spawning grounds.
In the planning of dam removal, Lauri maps watersheds and examines the longitudinal cross-sections of dams. The size of the upstream watershed is especially important. In addition, the slope of the flowing waters is significant, as different fish species tolerate varying gradients when migrating upstream.
"Scalgo Live dramatically streamlined our work, allowing us to focus on planning and communication with local stakeholders".
Lauri Harilainen, Watec Consulting Oy
The profile tool immediately shows how steep the dam is and how much the downstream slope needs to be adjusted so fish can reach their spawning areas.
"We use Scalgo Live to define the watershed, land use, and lake coverage, after which we can perform more detailed calculations," he explains.
Harilainen highlights the importance of Scalgo Live in projects like Töllinkoski dam removal.
"Previously, obtaining the necessary data required extensive manual work. Scalgo Live dramatically streamlined our work, allowing us to focus on planning and communication with local stakeholders."
The Töllinkoski restoration project was completed at the end of 2024. Now the freely flowing rapids of the Pusulanjoki provide the river’s strong trout population with a clear path to their breeding grounds.
Flood protection with two-stage channels
In Perniö, Southwest Finland, frequent flooding posed a challenge. Pekka Parkkila, a water management expert at the ELY Centre, the regional authority, managed the implementation of a two-stage river channel designed to mitigate flooding.
"With Scalgo Live, you can easily see where flood-prone areas are. I believe that if we surveyed Scalgo Live users here at the ELY Centre, the watershed delineation tool would be the most used and praised feature".
Pekka Parkkila, ELY Centre
The two-stage channel is far from ordinary. Its floodplains are exceptionally wide, in some places up to 10 meters across. Uniquely, this channel runs directly through the entire town center, stretching a full two kilometers in length. Typically, two-stage channels are planned in rural areas and designed for much smaller streams.
The construction phase of the two-stage channel in the urban area of Perniö.
The channel was constructed during dry weather to minimize sediment runoff, which could have had devastating effects on the river’s freshwater mussels.
Challenges did arise during the project. The riverbanks consist of erosion-prone clay, and in some areas landslides occurred during heavy rains.
"The erosion damage aligned with flow paths in Scalgo Live. This allowed us to anticipate the erosion-prone spots. The necessary areas were then reinforced with geotextile and gravel during excavation," explains Pekka.
Scalgo Live was used in advance to find the optimal locations where the riverbank needed erosion protection.
Pekka sees Scalgo Live as an unbeatable tool for quickly getting an overview of a project.
"With Scalgo Live, you can easily see where flood-prone areas are. I believe that if we surveyed Scalgo Live users here at the ELY Centre, the watershed delineation tool would be the most used and praised feature."
Comprehensive catchment-based planning
Tiina Kontio from SKVSY, a local lake trust in Eastern Finland, highlights the value of comprehensive catchment-based planning . Such plans consider entire watersheds, identifying strategic areas for interventions that improve water quality, reduce nutrient runoff, and enhance ecological stability.
The condition of Lake Sääksjärvi had already raised concerns among the locals. A preliminary study confirmed these concerns: nutrient load from agriculture was the main issue, leading to a deterioration of the lake's ecological status.
A site visit was conducted to identify a suitable location for a wetland.
"In Scalgo Live, I tested what would happen if I built a dam at a specific depression—what area would the water cover. The tool also made it easy to check if a nearby forest could be excluded from the wetland by building an embankment around it".
Tiina Kontio, SKVSY
Nutrient runoff needed to be reduced—for example, through soil management. The plan also proposed several water interventions aimed at improving water quality by retaining nutrients and suspended solids.
"For Sääksjärvi, we designed wetlands, water retention in ditches, two-stage channels, sequences of bottom dams, and sedimentation basins," says Tiina.
Kontio explored potential locations for wetlands through site visits and by analysing depressions in Scalgo Live. The platform made it possible to filter suitable locations in advance.
A suitable site for a wetland established through damming was found using Scalgo Live.
"In Scalgo Live, I tested what would happen if I built a dam at a specific depression—what area would the water cover. The tool also made it easy to check if a nearby forest could be excluded from the wetland by building an embankment around it," she explains.
Tiina believes that it is often easier to negotiate water protection with land owners than many other types of nature conservation projects. She has learned that every Finn holds a special connection to a particular body of water.
"Landowners and those living near lakes tend to have a very strong relationship with the water. That’s a great advantage when designing water protection measures."
